###### Accueil » Publications dans le domaines des technologies » 10-2017
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 Publications dans les journaux scientifiques dans le domaine de l'ingénierie : 10-2017 trié par par titre, page: 2
» An Analytical Approach to Detect Generator Loss of Excitation Based on Internal Voltage Calculation
 Résumé:The excitation system of a synchronous generator has a major role in proper operation and control of the generator. Loss of excitation (LOE) may cause harmful effects on the both generator and power system. This paper presents a new approach to detect LOE based on calculating the synchronous generator internal voltage. This parameter is considerably sensitive to LOE and can be used as a straightforward index to discriminate LOE events from system disturbances more quickly and robustly than the conventional indices. A novel and practical technique with minimum computational burden is presented to calculate the generator internal voltage. To evaluate the proposed algorithm, LOE events in a multimachine test system are investigated. In addition, the proposed approach is experimentally evaluated on a 10 kVA synchronous generator. Performed studies demonstrate that the proposed strategy not only noticeably decreases the LOE relay operation time, but also desensitizes its maloperation to system disturbances. Auteurs: Moein Abedini;Majid Sanaye-Pasand;Mahdi Davarpanah; Apparue dans: IEEE Transactions on Power Delivery Date publication: 10.-2017, volume: 32, issue:5, pages: 2329 - 2338 Editeur: IEEE Document complet vers site de l'éditeur
» An Analytical Solution to Optimal Stator Current Design for PMSM Torque Ripple Minimization With Minimal Machine Losses
 Résumé:This paper investigates torque ripple minimization for permanent-magnet synchronous machines (PMSM), and proposes a novel analytical solution of optimal stator current design for torque ripple minimization. The proposed design is theoretically proven to be able to minimize the torque ripple with minimal machine losses. Moreover, the optimal stator current is computed from analytical expression, which is computationally efficient. Therefore, the proposed approach is applicable for torque ripple minimization under both transient state and steady state. However, existing approaches usually employ optimization algorithm to optimize the stator current, which is computationally complex and involves iterative computation, so their applicability is limited under transient state, because the optimal stator current must be adaptively updated with respect to operating conditions. Moreover, magnetic saturation is considered in the proposed approach by employing a novel linear model to model the relation between the inductance and the stator current under maximum torque per ampere (MTPA) control. In this way, the proposed analytical solution does not involve inductance, and thus, the influence of magnetic saturation can be effectively reduced. The proposed approach is validated on a laboratory PMSM drive system under both transient state and steady state. Auteurs: Guodong Feng;Chunyan Lai;Narayan C. Kar; Apparue dans: IEEE Transactions on Industrial Electronics Date publication: 10.-2017, volume: 64, issue:10, pages: 7655 - 7665 Editeur: IEEE Document complet vers site de l'éditeur
» An Annotation Agnostic Algorithm for Detecting Nascent RNA Transcripts in GRO-Seq
 Résumé:We present a fast and simple algorithm to detect nascent RNA transcription in global nuclear run-on sequencing (GRO-seq). GRO-seq is a relatively new protocol that captures nascent transcripts from actively engaged polymerase, providing a direct read-out on bona fide transcription. Most traditional assays, such as RNA-seq, measure steady state RNA levels which are affected by transcription, post-transcriptional processing, and RNA stability. GRO-seq data, however, presents unique analysis challenges that are only beginning to be addressed. Here, we describe a new algorithm, Fast Read Stitcher (FStitch), that takes advantage of two popular machine-learning techniques, hidden Markov models and logistic regression, to classify which regions of the genome are transcribed. Given a small user-defined training set, our algorithm is accurate, robust to varying read depth, annotation agnostic, and fast. Analysis of GRO-seq data without a priori need for annotation uncovers surprising new insights into several aspects of the transcription process. Auteurs: Joseph G. Azofeifa;Mary A. Allen;Manuel E. Lladser;Robin D. Dowell; Apparue dans: IEEE/ACM Transactions on Computational Biology and Bioinformatics Date publication: 10.-2017, volume: 14, issue:5, pages: 1070 - 1081 Editeur: IEEE Document complet vers site de l'éditeur
» An Annulus-Sector Segmented Primary Mirror
 Résumé:Ultrahigh resolution optical imaging with large aperture is increasingly desired in space-based remote sensing and imaging system, but it is usually limited by volume and mass constraints of launch vehicle due to size and weight of the imaging system. In this paper, an annulus-sector segment primary mirror is presented, which is in high obscuration with circularity symmetrical annulus-sector around. The different structure types of the annulus-sector segment aperture are discussed, while two important parameters, width–diameter ratio and the subaperture angle are also studied. An annulus-sector optical lens is processed to verify the image performance. Experimental results show that modulation transfer function of annulus-sector segment optical system can be up to 0.23(50 lp/mm), which approaches the optical resolution of full aperture optical system with smaller size and lighter weight. Auteurs: X. X. Wei;X. J. Wan;B. Yang; Apparue dans: IEEE Photonics Journal Date publication: 10.-2017, volume: 9, issue:5, pages: 1 - 9 Editeur: IEEE Document complet vers site de l'éditeur
» An Approach for Building Efficient and Accurate Social Recommender Systems Using Individual Relationship Networks
 Résumé:Social recommender system, using social relation networks as additional input to improve the accuracy of traditional recommender systems, has become an important research topic. However, most existing methods utilize the entire user relationship network with no consideration to its huge size, sparsity, imbalance, and noise issues. This may degrade the efficiency and accuracy of social recommender systems. This study proposes a new approach to manage the complexity of adding social relation networks to recommender systems. Our method first generates an individual relationship network (IRN) for each user and item by developing a novel fitting algorithm of relationship networks to control the relationship propagation and contracting. We then fuse matrix factorization with social regularization and the neighborhood model using IRN's to generate recommendations. Our approach is quite general, and can also be applied to the item-item relationship network by switching the roles of users and items. Experiments on four datasets with different sizes, sparsity levels, and relationship types show that our approach can improve predictive accuracy and gain a better scalability compared with state-of-the-art social recommendation methods. Auteurs: Surong Yan;Kwei-Jay Lin;Xiaolin Zheng;Wenyu Zhang;Xiaoqing Feng; Apparue dans: IEEE Transactions on Knowledge and Data Engineering Date publication: 10.-2017, volume: 29, issue:10, pages: 2086 - 2099 Editeur: IEEE Document complet vers site de l'éditeur
» An E-Mode p-Channel GaN MOSHFET for a CMOS Compatible PMIC
 Résumé:The operation principle of a low power E-mode p-channel GaN MOSHFET is explained via TCAD simulations. The challenges of achieving negative threshold voltage with the scaling of gate length are addressed by adjusting the mole fraction of an AlGaN cap layer beneath the gate. An inverter consisting of the proposed p-channel GaN MOSHFET with a gate length of $0.25~\mu \text{m}$ shows promise of a CMOS compatible power management IC in the megahertz range. Auteurs: Ashwani Kumar;Maria Merlyne De Souza; Apparue dans: IEEE Electron Device Letters Date publication: 10.-2017, volume: 38, issue:10, pages: 1449 - 1452 Editeur: IEEE Document complet vers site de l'éditeur
» An Efficient Algorithm for Optimally Reshaping the TP Model Transformation
 Résumé:The tensor product (TP) model transformation is an emerging technique for the ongoing system analysis and design works of recent years, where its integration with the linear matrix inequalities (LMIs)-based methods can be powerful solution. However, one of the main issues is encountered that the performance of the LMI conditions depends heavily on the tightness of the TP models. This brief proposes an efficient TP model reshaping algorithm toward tightening TP models. A novel index is introduced to quantize the tightness of TP models such that an optimal reshaping can be realized. Besides, a random search following a recursive reshaping strategy is developed, which intensively enhances the efficiency of the reshaping process. The efficiency and effectiveness of the algorithm are demonstrated via a series of numerical simulations. Auteurs: Xiangdong Liu;Yin Yu;Zhen Li;Herbert H. C. Iu;Tyrone Fernando; Apparue dans: IEEE Transactions on Circuits and Systems II: Express Briefs Date publication: 10.-2017, volume: 64, issue:10, pages: 1187 - 1191 Editeur: IEEE Document complet vers site de l'éditeur
» An Efficient and Stable 2-D/3-D Hybrid Discontinuous Galerkin Time-Domain Analysis With Adaptive Criterion for Arbitrarily Shaped Antipads in Dispersive Parallel-Plate Pair
 Résumé:A hybrid 2-D and 3-D discontinuous Garlerkin time-domain (DGTD) method is proposed for transient analysis of multiple arbitrarily shaped antipads in a dispersive parallel-plate pair. In the proposed hybrid method, the domains where only the zeroth-order parallel-plate mode exists are modeled by the 2-D DGTD, and the remaining domains are modeled by the 3-D DGTD. Each element is independent with others, thus easily parallelizable. Because higher order modes will propagate in the parallel-plate pair, the spatial domain decomposition should be time-dependent. For domain decomposition criterion at time step $\text {t}_{\text {n}}$ , the electromagnetic field distribution at the previous time step $\text {t}_{\text {n-1}}$ is analyzed to identify the zeroth-order parallel mode domain. Compared with the classical static distance criterion, this new adaptive criterion makes the approximation error under control, thus enhancing the stability. The accuracy and flexibility of the hybrid method have been validated by comparison with commercial software. Its enhancement of efficiency and stability is also demonstrated. Auteurs: Wending Mai;Jun Hu;Ping Li;Huapeng Zhao; Apparue dans: IEEE Transactions on Microwave Theory and Techniques Date publication: 10.-2017, volume: 65, issue:10, pages: 3671 - 3681 Editeur: IEEE Document complet vers site de l'éditeur
» An Efficient Buck/Buck-Boost Reconfigurable LED Driver Employing SIN2 Reference
 Résumé:An efficient buck/buck-boost reconfigurable LED driver based on peak current control is introduced. The driver supports pulse-width modulation (PWM) and pulse-frequency modulation (PFM) operations. The use of a combination of rectified sin and sin2 functions in the reference is introduced for the purpose of improving the power factor (PF) and total harmonic distortion (THD) of buck and buck-boost converters. The optimal reference waveform shape for buck and buck/boost modes can be set externally. The design ensures that the peak of the inductor current maintains a constant level that is invariant for different ac line voltages. The LED driver has been implemented in a 130-nm CMOS process. PF and THD are improved when the proposed reference is employed, and the peak PF and lowest THD values are 0.995/0.983/0.996 and 7.8/6.2/3.5% for the buck (PWM), buck (PFM), and buck-boost (PFM) cases, respectively. The corresponding peak efficiency for the three cases is 88/92/91%, respectively. Auteurs: Kunhee Cho;Ranjit Gharpurey; Apparue dans: IEEE Journal of Solid-State Circuits Date publication: 10.-2017, volume: 52, issue:10, pages: 2758 - 2768 Editeur: IEEE Document complet vers site de l'éditeur
» An Efficient Contrast Enhancement Method for Remote Sensing Images
 Résumé:Remote sensing images often suffer low contrast. Although many contrast enhancement methods have been proposed in recent literature, the efficiency and robustness of remote sensing image contrast enhancement is still a challenge. In this letter, a novel self-adaptive histogram compacting transform-based contrast enhancement method for remote sensing images is presented to meet with the requirements of automation, robustness, and efficiency in applications. First, the histogram of an input image is optimized into compact and continuous status with the constraints of the merging cost, the moderate global brightness, and the entropy contribution of gray levels. Then, a local remapping algorithm is proposed to catch more details during the course of gray extending with the linear stretch. Finally, a dual-gamma transform is proposed to enhance the contrast in both bright and black areas. Experimental and comparison results demonstrate that the proposed method yields better results than the state-of-the-art methods and maintains robustness in different cases. It provides an effective approach for remote sensing image automatic contrast enhancement. Auteurs: Jiahang Liu;Chenghu Zhou;Peng Chen;Chaomeng Kang; Apparue dans: IEEE Geoscience and Remote Sensing Letters Date publication: 10.-2017, volume: 14, issue:10, pages: 1715 - 1719 Editeur: IEEE Document complet vers site de l'éditeur
» An Efficient Hierarchical Banking Structure for Algorithmic Multiported Memory on FPGA
 Résumé:Algorithmic multiported memory supports concurrent accesses by cooperating block RAMs (BRAMs) with algorithmic operations, and demonstrates the better performance per resource usage on FPGA when compared with register-based designs. However, the current approaches still use significant amount of FPGA resources and pose great design challenges when increasing the access ports. This paper proposes HB-NTX with a resource efficient hierarchical banking structure for nontable-based multi-ported memory design on FPGA. The regular design style enables a systematic flow to scale both read and write ports. When compared with the previous approaches, HB-NTX can reduce 62.03% BRAMs when composing a 2R4W memory with 32K depth. This paper further extends the HB-NTX to alleviate the complexity of the table-based memory designs. When compared with the previous table-based TBLVT approach, the proposed design for a 2R4W memory with 8K depth attains the cost reduction of 39.9%, 14.3%, and 15.6%, for registers, lookup tables, and BRAMs, respectively. Auteurs: Bo-Cheng Charles Lai;Kun-Hua Huang; Apparue dans: IEEE Transactions on Very Large Scale Integration Systems Date publication: 10.-2017, volume: 25, issue:10, pages: 2776 - 2788 Editeur: IEEE Document complet vers site de l'éditeur
» An Efficient Load Balancing of Gateways Using Improved Shuffled Frog Leaping Algorithm and Novel Fitness Function for WSNs
 Résumé:Energy consumption is one of the important factors in wireless sensor networks (WSNs) design. As energy is a limited resource, energy consumption problem in WSNs has become a fast growing problem, and there is a need of efficient and robust algorithms for load balancing in WSNs. This energy is needed for sensor nodes operations. In order to maximize the network lifetime, energy consumption should be optimized. In cluster-based WSNs, cluster heads or gateways perform activities, such as data collection from its member nodes, data aggregation, and data exchange with the base station. Hence, load balancing of gateways in WSNs is one of the crucial and challenging tasks to maximize network lifetime. In order to address this problem, in this paper, shuffled frog leaping algorithm (SFLA) is improved by suitably modifying the frog’s population generation and off-spring generation phases in SFLA and by introducing a transfer phase. A novel fitness function is also designed to evaluate the quality of the solutions produced by the improved SFLA. We performed extensive simulations of the proposed load balancing algorithm in terms of various performance parameters. The experimental results are encouraging and demonstrated the efficiency of the proposed algorithm. Auteurs: Damodar Reddy Edla;Amruta Lipare;Ramalingaswamy Cheruku;Venkatanareshbabu Kuppili; Apparue dans: IEEE Sensors Journal Date publication: 10.-2017, volume: 17, issue:20, pages: 6724 - 6733 Editeur: IEEE Document complet vers site de l'éditeur
» An Efficient Polyphase Filter-Based Resampling Method for Unifying the PRFs in SAR Data
 Résumé:Variable higher pulse repetition frequencies (PRFs) are increasingly being used to meet the stricter requirements and complexities of current airborne and spaceborne synthetic aperture radar (SAR) systems associated with higher resolution and wider area products. POLYPHASE, the proposed resampling scheme, downsamples and unifies variable PRFs within a single look complex SAR acquisition and across a repeat pass sequence of acquisitions down to an effective lower PRF. A sparsity condition of the received SAR data ensures that the uniformly resampled data approximate the spectral properties of a decimated densely sampled version of the received SAR data. While experiments conducted with both synthetically generated and real airborne SAR data show that POLYPHASE retains comparable performance with the state-of-the-art best linear unbiased interpolation scheme in image quality, a polyphase filter-based implementation of POLYPHASE offers significant computational savings for arbitrary (not necessarily periodic) input PRF variations, thus allowing fully on-board, in-place, and real-time implementation. Auteurs: Yoangel Torres;Kamal Premaratne;Falk Amelung;Shimon Wdowinski; Apparue dans: IEEE Transactions on Geoscience and Remote Sensing Date publication: 10.-2017, volume: 55, issue:10, pages: 5741 - 5754 Editeur: IEEE Document complet vers site de l'éditeur
» An Efficient Privacy-Preserving Outsourced Computation over Public Data
 Résumé:In this paper, we propose a new efficient privacy-preserving outsourced computation framework over public data, called EPOC. EPOC allows a user to outsource the computation of a function over multi-dimensional public data to the cloud while protecting the privacy of the function and its output. Specifically, we introduce three types of EPOC in order to tradeoff different levels of privacy protection and performance. We present a new cryptosystem called Switchable Homomorphic Encryption with Partially Decryption (SHED) as the core cryptographic primitive for EPOC. We introduce two coding techniques, called message pre-coding technique and message extending and coding technique respectively, for messages encrypted under a composite order group. Furthermore, we propose a Secure Exponent Calculation Protocol with Public Base (SEPB), which serves as the core sub-protocol in EPOC. Detailed security analysis shows that the proposed EPOC achieves the goal of outsourcing computation of a private function over public data without privacy leakage to unauthorized parties. In addition, performance evaluations via extensive simulations demonstrate that EPOC is efficient in both computation and communications. Auteurs: Ximeng Liu;Baodong Qin;Robert H. Deng;Yingjiu Li; Apparue dans: IEEE Transactions on Services Computing Date publication: 10.-2017, volume: 10, issue:5, pages: 756 - 770 Editeur: IEEE Document complet vers site de l'éditeur
» An Efficient Procedure for Bilayer-Expurgated LDPC Codes Design in Cooperative Relay Channels
 Résumé:This letter proposes a fast optimization procedure to design bilayer-expurgated low density parity check codes in the relay channel. The code optimization problem aims to maximize the code rate while guaranteeing the convergence of the density evolution relations in upper and lower layer codes. The original problem is linear programming. Nevertheless, it suffers from high computational complexity, as it is semi-infinite programming (SIP) in a 2-D continuous interval. To efficiently solve it, we first approximate the density evolutions by polynomials. Then, leveraging optimization problems over the solution of sum of square multivariate polynomials the problem is transformed to semi-definite programming (SDP), where the global solution can be found efficiently using available SDP solvers. Our simulation shows that our approach results in significantly lower computational complexity with respect to the well-known method of quantization for solving the SIP problem, while both achieve the same performance. Auteurs: Sajad Mehrizi;Sara Khosravi;Mahmoud Ahmadian; Apparue dans: IEEE Communications Letters Date publication: 10.-2017, volume: 21, issue:10, pages: 2114 - 2117 Editeur: IEEE Document complet vers site de l'éditeur
» An Eigen-Binding Site Based Method for the Analysis of Anti-EGFR Drug Resistance in Lung Cancer Treatment
 Résumé:We explore the drug resistance mechanism in non-small cell lung cancer treatment by characterizing the drug-binding site of a protein mutant based on local surface and energy features. These features are transformed to an eigen-binding site space and used for drug resistance level prediction and analysis. Auteurs: Lichun Ma;Debby D. Wang;Bin Zou;Hong Yan; Apparue dans: IEEE/ACM Transactions on Computational Biology and Bioinformatics Date publication: 10.-2017, volume: 14, issue:5, pages: 1187 - 1194 Editeur: IEEE Document complet vers site de l'éditeur
» An End-Member-Based Two-Source Approach for Estimating Land Surface Evapotranspiration From Remote Sensing Data
 Résumé:Evapotranspiration (ET) is one of the key variables in the water and energy exchange between land surface and atmosphere. This paper develops an end-member-based two-source approach for estimating land surface ET (i.e., the ESVEP model) from remote sensing data, considering the differing responses of soil water content at the upper surface layer to soil evaporation and at the deeper root zone layer to vegetation transpiration. The ESVEP model first diverges the soil-vegetation system net radiation into soil and vegetation components by considering the transmission of direct and diffuse shortwave radiation separately from the transmission of longwave radiation through the canopy, then calculates the four dry/wet soil/vegetation end-members with the diverged soil and vegetation net radiations, and last separates soil evaporation from vegetation transpiration based on the two-phase ET dynamics and the four end-member temperatures. The model can overall produce reasonably good surface energy fluxes and is no more sensitive to meteorology, vegetation, and remote sensing inputs than other two-source energy balance models and surface temperature versus vegetation index ( $T_{R}$ –VI) trapezoid models. A reasonable agreement could be found with a small bias of ±8 W/ $\text{m}^{2}$ and a root-mean-square error within 60 W/ $\text{m}^{2}$ (comparable to accuracies published in other studies) when both model-estimated sensible heat flux and latent heat flux from MODIS remote sensing data are validated with ground-based large aperture scintillometer measurements. Auteurs: Ronglin Tang;Zhao-Liang Li; Apparue dans: IEEE Transactions on Geoscience and Remote Sensing Date publication: 10.-2017, volume: 55, issue:10, pages: 5818 - 5832 Editeur: IEEE Document complet vers site de l'éditeur
» An Enhanced Access Reservation Protocol With a Partial Preamble Transmission Mechanism in NB-IoT Systems
 Résumé:We propose an enhanced access reservation protocol (ARP) with a partial preamble transmission mechanism for the narrow band Internet of Things (NB-IoT) systems. The proposed ARP can enhance the ARP performance by mitigating the occurrence of preamble collisions, while being compatible with the conventional NB-IoT ARP. We provide an analytical model that captures the performance of the proposed ARP in terms of false alarm, misdetection, and collision probabilities. Moreover, we investigate a tradeoff between the misdetection and the collision probabilities, and optimize the proposed ARP according to the system loads. The results show that the proposed ARP outperforms the conventional NB-IoT ARP, in particular, at heavier system loads. Auteurs: Taehoon Kim;Dong Min Kim;Nuno Pratas;Petar Popovski;Dan Keun Sung; Apparue dans: IEEE Communications Letters Date publication: 10.-2017, volume: 21, issue:10, pages: 2270 - 2273 Editeur: IEEE Document complet vers site de l'éditeur
» An Equivalent Circuit Model for Nested Split-Ring Resonators
 Résumé:In this paper, an equivalent circuit model for nested split-ring resonators (NSRRs) is proposed. NSRRs are an emerging class of split ring resonators, preferred in a range of areas from sensing in biomedical or civil engineering applications to antenna design, due to their more compact size and enhanced sensitivity/resolution characteristics over the conventional SRRs. In the proposed model, the NSRR structure is treated as a combination of basic elements, i.e., strips and gaps, and the electromagnetic characteristics of the whole geometry are expressed in terms of capacitances and inductances of each of these elements. The outputs of the model are compared with those obtained via full-wave simulations using the package programs as well as measurements. The variation of NSRR resonance frequency ( $f_{\text {res}}$ ) with all important design parameters is also compared with full-wave simulations. In all comparisons, the results demonstrate agreement, showing that the proposed model can correctly explain the electromagnetics of the NSRR structure and that it provides an intuitive way for a better and easier analysis and a preliminary design of normally complex structures. Auteurs: Burak Ozbey;Ayhan Altintas;Hilmi Volkan Demir;Vakur B. Ertürk; Apparue dans: IEEE Transactions on Microwave Theory and Techniques Date publication: 10.-2017, volume: 65, issue:10, pages: 3733 - 3743 Editeur: IEEE Document complet vers site de l'éditeur
» An Experimental Investigation into the Impact of Vehicular Traffic on Interpersonal Wearable-to-Wearable Communications Channels
 Résumé:In this paper, we have investigated the effects of vehicular traffic on interpersonal wearable-to-wearable (W2W) communications channels in an urban environment at 2.45 GHz. In particular, we have studied the perturbations in the received signal caused by different types of vehicles as they passed through a channel between two persons who maintained various relative orientations while positioned at the opposite sides of a road. As the channel underwent different fading mechanisms depending on whether the vehicle was approaching, transitioning (i.e., intersecting the direct signal path), or receding from the persons, the overall disturbance was appropriately segmented depending on the journey stage. The results have shown that relative body orientation was a significant factor when considering the impact that a vehicle can have on a W2W link. When both persons faced the oncoming traffic, the link was particularly susceptible to significant fading events with variations in the received signal power from the unperturbed state as great as 44.1 dB observed to occur. For all of the journey stages, irrespective of the relative orientation of the persons, the logarithmically transformed long-term fading process was found to be multimodal and well described by a Gaussian mixture model. During the transitioning phase, shadowing caused by the passing automobile obstructing the line-of-sight signal path was found to be the main contributor to the signal fading. However, probably the most remarkable result of the channel characterization work conducted in this paper was the severity of the short-term fading often observed. Such was the intensity of the measured envelope fluctuation in many of the scenarios, we have been able to utilize the recently proposed $\kappa -\mu$ extreme distribution with great success and in the process, provide a further important empirical validation of this new fading model.- Moreover, we have used the resistor-average distance, which is derived from the Kullback–Leibler distance to show the improved fit that the $\kappa -\mu$ extreme distribution offers compared with the $\kappa -\mu$ distribution when used to model the W2W channel in this fading environment. Auteurs: Michael G. Doone;Simon L. Cotton;Claude Oestges; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 10.-2017, volume: 65, issue:10, pages: 5418 - 5430 Editeur: IEEE Document complet vers site de l'éditeur
» An Exploratory Study of Word-Scale Graphics in Data-Rich Text Documents
 Résumé:We contribute an investigation of the design and function of word-scale graphics and visualizations embedded in text documents. Word-scale graphics include both data-driven representations such as word-scale visualizations and sparklines, and non-data-driven visual marks. Their design, function, and use has so far received little research attention. We present the results of an open ended exploratory study with nine graphic designers. The study resulted in a rich collection of different types of graphics, data provenance, and relationships between text, graphics, and data. Based on this corpus, we present a systematic overview of word-scale graphic designs, and examine how designers used them. We also discuss the designers’ goals in creating their graphics, and characterize how they used word-scale graphics to visualize data, add emphasis, and create alternative narratives. Building on these examples, we discuss implications for the design of authoring tools for word-scale graphics and visualizations, and explore how new authoring environments could make it easier for designers to integrate them into documents. Auteurs: Pascal Goffin;Jeremy Boy;Wesley Willett;Petra Isenberg; Apparue dans: IEEE Transactions on Visualization and Computer Graphics Date publication: 10.-2017, volume: 23, issue:10, pages: 2275 - 2287 Editeur: IEEE Document complet vers site de l'éditeur
» An FSS Structure Based on Parallel LC Resonators for Multiband Applications
 Résumé:An frequency selective surface (FSS) structure based on parallel LC resonators is proposed to achieve multiband bandpass filtering responses. The parallel LC resonator, implemented by a via-connected metallic line and a parallel-plate capacitor (PPC), serves as the basic element for intentionally constructing FSS unit cell, which exhibits a single-band bandpass filtering response. As a result, the proposed FSS structure can provide a multiband performance by introducing multiple VCMLs and PPCs with different resonance frequencies. Because of the compact resonator resulting from a PPC, the proposed FSSs feature miniaturized unit cell size inherently, for example, the single-band FSS element is as compact as 4.8% of the operating wavelength. Moreover, this kind of FSS structure is also beneficial for independent control of the frequency performance under different polarizations, efficient optimal design of desired resonance frequencies, and easy realization of multiband response with wideband ratio range (e.g., 1.13 to 3.32 for the dual-band FSS). Equivalent circuits of these FSSs are established for explaining the resonating mechanisms and precisely modeling the frequency performances. Finally, prototypes of the dual- and tri-band FSSs are fabricated and measured. The measured results exhibit stable filtering performance under different polarizations and incidence angles (up to 60°). Auteurs: Peng-Chao Zhao;Zhi-Yuan Zong;Wen Wu;Bo Li;Da-Gang Fang; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 10.-2017, volume: 65, issue:10, pages: 5257 - 5266 Editeur: IEEE Document complet vers site de l'éditeur
» An hp-adaptive discretization algorithm for signed distance field generation
 Résumé:In this paper we present an $hp$-adaptive algorithm to generate discrete higher-order polynomial Signed Distance Fields (SDFs) on axis-aligned hexahedral grids from manifold polygonal input meshes. Using an orthonormal polynomial basis, we efficiently fit the polynomials to the underlying signed distance function on each cell. The proposed error-driven construction algorithm is globally adaptive and iteratively refines the SDFs using either spatial subdivision ($h$-refinement) following an octree scheme or by cell-wise adaption of the polynomial approximation's degree ($p$-refinement). We further introduce a novel decision criterion based on an error-estimator in order to decide whether to apply $p$- or $h$-refinement. We demonstrate that our method is able to construct more accurate SDFs at significantly lower memory consumption compared to previous approaches. While the cell-wise polynomial approximation will result in highly accurate SDFs, it can not be guaranteed that the piecewise approximation is continuous over cell interfaces. Therefore, we propose an optimization-based post-processing step in order to weakly enforce continuity. Finally, we apply our generated SDFs as colli- ion detector to the physically-based simulation of geometrically highly complex solid objects in order to demonstrate the practical relevance and applicability of our method. Auteurs: Dan Koschier;Crispin Deul;Magnus Brand;Jan Bender; Apparue dans: IEEE Transactions on Visualization and Computer Graphics Date publication: 10.-2017, volume: 23, issue:10, pages: 2208 - 2221 Editeur: IEEE Document complet vers site de l'éditeur
» An Identity-Based Data Aggregation Protocol for the Smart Grid
 Résumé:The smart grid significantly improves the reliability, efficiency, security, and sustainability of electricity services. It plays an important role in modern energy infrastructure. A drawback of this new technique, however, is that the fine-grained metering data may leak private customer information. Thus, various public-key based data aggregation protocols for privacy protection have been proposed. However, the National Institute of Standards and Technology has recommended not using public-key based cryptography in the smart grid, since maintaining the public-key infrastructure is a heavy cost. In this paper, we propose an identity-based data aggregation protocol for the smart grid, which cannot only prevent unauthorized reading and fine-grained analyzing but can also protect against unintentional errors and maliciously altered messages. The basic building block of our protocol is an identity-based encryption and signature scheme in which an identity-based encryption scheme is combined with an identity-based signature scheme. They share the same private/public parameters, which greatly reduces the complexity of the protocol in the smart grid. Security analysis demonstrates the effectiveness of our protocol in the context of six typical attacks against the smart grid. A prototype implementation based on the Intel Edison platform shows that our protocol is efficient enough for physically constrained smart grid operators, such as smart meters. Auteurs: Zhiwei Wang; Apparue dans: IEEE Transactions on Industrial Informatics Date publication: 10.-2017, volume: 13, issue:5, pages: 2428 - 2435 Editeur: IEEE Document complet vers site de l'éditeur
» An Implementation of Hybrid Control Strategy for Distributed Generation System Interface Using Xilinx System Generator
 Résumé:This paper presents an analytical study and hardware-in-loop (HIL) cosimulation design of a grid-connected inverter system with a combinational robust observer-based modified repetitive current controller. In this study, main attention is paid to improve power quality and tracking performance of a distributed generation (DG) interfacing system under various perturbations. The inherent delay in convergence of conventional repetitive controller (RC) is reduced by introducing a low pass filter in delay line and this configuration is named as modified RC (MRC). By adding an observer with MRC, system states can be reconstructed, which improve the system dynamic response. Robust stability and convergence criterion are derived in terms of linear matrix inequality using combined Lyapunov function and singular value decomposition technique, which determine the suitable parameters of feedback control and state observer gains. By utilizing these gains, the switching signals are generated to operate the DG interfacing inverter effectively. The performance of proposed controller is compared with traditional proportional integral, proportional resonant, and MRC under both normal and fault conditions. Finally, HIL cosimulation is performed by realizing the power circuit in MATLAB/Simulink as a simulation model and a control structure using Xilinx system generator platform as burnt in hardware Virtex-6 field programmable gate array (FPGA) ML605 evaluation kit. Auteurs: Smitha Joyce Pinto;Gayadhar Panda;Rangababu Peesapati; Apparue dans: IEEE Transactions on Industrial Informatics Date publication: 10.-2017, volume: 13, issue:5, pages: 2735 - 2745 Editeur: IEEE Document complet vers site de l'éditeur
» An Improved 6-D Pose Detection Method Based on Opposing-Magnet Pair System and Constraint Multiple Magnets Tracking Algorithm
 Résumé:Magnetic tracking method is mainly based on sensing of the magnetic field generated by the magnetic source. Usually a small permanent magnet is used as the magnetic source, and magnetic dipole model is used to estimate the magnetic field. The disadvantage of this approach is that only 5-D pose information can be estimated, but the spin rotation with respect to the direction of magnetic moment cannot be detected. In our previous work, we proposed a novel 6-D (3-D position and 3-D orientation) pose detection method, which was based on an opposing-magnet pair system. The disadvantage is that different rotational parameters may lead to the same pose result due to the symmetric structure of object magnets. In order to solve this problem, we propose an improved 6-D pose detection method in this paper, which is based on a novel constraint multiple magnets tracking algorithm. Two magnets of different sizes with opposite magnetic directions have been combined together to serve as the tracking target. By applying the constraint multi-magnet tracking algorithm, 5-D pose of each magnet can be obtained. Therefore, we can estimate the missing spin rotational information according to the relative movement between these two magnets. Experimental results verified the feasibility of the proposed method. The average position error is 2.3 mm and the orientation error is 4.36°, when the volume ratio between these two magnets is 1:1.5. Auteurs: Shuang Song;Xiaoxiao Qiu;Wei Liu;Max Q.-H. Meng; Apparue dans: IEEE Sensors Journal Date publication: 10.-2017, volume: 17, issue:20, pages: 6752 - 6759 Editeur: IEEE Document complet vers site de l'éditeur
» An Improved Arc Flash Energy Calculation Method and Its Application
 Résumé:In this paper, we describe an improved algorithm for arc flash calculations. This method can be used in any software that performs arc flash calculations to determine the incident energy, arc flash boundaries, and other related parameters for arc flash risk assessment purposes. The method provides a more sophisticated and precise way of calculating short circuit contributions to the fault location. To illustrate the effectiveness of the method, a typical renewable power plant (wind energy) with common types of protection is analyzed. The arc flash risk assessment results are compared in both the conventional way and the presented method. The new approach is called the Integrated Method. This method is an accurate way of modelling the short circuit contribution of the devices, which can potentially change the total short circuit current at the fault location. This Integrated Method considers the decay of the contributing machines and the devices where currents are interrupted due to a protection device. It also accounts for the current decays over time. Auteurs: Afshin Majd;Robert Luo; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 5062 - 5067 Editeur: IEEE Document complet vers site de l'éditeur
» An Improved Delayed Signal Cancellation PLL for Fast Grid Synchronization Under Distorted and Unbalanced Grid Condition
 Résumé:Cascasded delayed signal cancellation (DSC) phase-locked loop (PLL) technique has been attractive for grid synchronization under nonideal grid voltage due to its good harmonics filtering capability. However, it has to face the challenge of slow dynamic response. In this paper, an improved DSC-PLL that features high filtering capability, fast dynamic response and simple structure is presented. This PLL employs only one DSC block and one moving average filter (MAF) block to eliminate all even-order and odd-order harmonics while a second-order phase lead compensator and q-axis feedforward path are introduced to increase the PLL bandwidth. The effect of the phase lead compensator on PLL dynamic performance is analyzed. The feedforward path works only when grid voltage frequency or phase jumps and will not affect the steady state behaviors. Therefore, the PLL can improve the phase estimation accuracy and dynamic speed at the same time even under highly distorted and unbalanced grid voltage. Moreover, linear Lagrange interpolation method is adopted to reduce the discretized errors in the digital implementation of the PLL. The effectiveness of the proposed method is validated by both simulation and experimental results. The comparison results with the existing cascaded DSC-PLL and standard MAF-PLL are also presented. Auteurs: Qicheng Huang;Kaushik Rajashekara; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 4985 - 4997 Editeur: IEEE Document complet vers site de l'éditeur
» An Improved Zero-Current-Switching Single-Phase Transformerless PV H6 Inverter With Switching Loss-Free
 Résumé:In this paper, a switching loss-free (SLF) concept for the first six-switches H-bridge inverter (H6-I) topology is proposed. SLF means that its switches are able to operate with soft turn-on and turn-off transitions. In order to implement the SLF goal, a new resonance-trajectory is proposed. Compared with the zero-current-transition H6-I (ZCT-H6-I) topology published in previous literature, the proposed resonance-trajectory can precisely compensate for losses of resonant tanks every switching period. With this intention, an implementing circuit is structured based on the H6-I topology, and its detailed operation principle and performance characteristics are analyzed. As a result, all active switches of the new circuit are switched under zero-current turn-on and zero-current turn-off conditions. Also, the reverse recovery problem of freewheeling diodes is alleviated owing to the zero-current turn-off property of diodes. The SLF target is realized in theory. Finally, experimental results from a 1 kW prototype at 50 kHz switching frequency are provided to verify the effectiveness of the proposed SLF concept in practice. Specifically, the conversion efficiency of the new circuit is over 95% in a wide load range, and there is roughly a 1.5% efficiency improvement compared with the hard-switching H6-I topology. Auteurs: Hua F. Xiao;Li Zhang;Yanqing Li; Apparue dans: IEEE Transactions on Industrial Electronics Date publication: 10.-2017, volume: 64, issue:10, pages: 7896 - 7905 Editeur: IEEE Document complet vers site de l'éditeur
» An Incremental Learning of Concept Drifts Using Evolving Type-2 Recurrent Fuzzy Neural Networks
 Résumé:The age of online data stream and dynamic environments results in the increasing demand of advanced machine learning techniques to deal with concept drifts in large data streams. Evolving fuzzy systems (EFS) are one of recent initiatives from the fuzzy system community to resolve the issue. Existing EFSs are not robust against data uncertainty, temporal system dynamics, and the absence of system order, because a vast majority of EFSs are designed in the type-1 feedforward network architecture. This paper aims to solve the issue of data uncertainty, temporal behavior, and the absence of system order by developing a novel evolving recurrent fuzzy neural network, called evolving type-2 recurrent fuzzy neural network (eT2RFNN). eT2RFNN is constructed in a new recurrent network architecture, featuring double recurrent layers. The new recurrent network architecture evolves a generalized interval type-2 fuzzy rule, where the rule premise is built upon the interval type-2 multivariate Gaussian function, whereas the rule consequent is crafted by the nonlinear wavelet function. The eT2RFNN adopts a holistic concept of evolving systems, where the fuzzy rule can be automatically generated, pruned, merged, and recalled in the single-pass learning mode. eT2RFNN is capable of coping with the problem of high dimensionality because it is equipped with online feature selection technology. The efficacy of eT2RFNN was experimentally validated using artificial and real-world data streams and compared with prominent learning algorithms. eT2RFNN produced more reliable predictive accuracy, while retaining lower complexity than its counterparts. Auteurs: Mahardhika Pratama;Jie Lu;Edwin Lughofer;Guangquan Zhang;Meng Joo Er; Apparue dans: IEEE Transactions on Fuzzy Systems Date publication: 10.-2017, volume: 25, issue:5, pages: 1175 - 1192 Editeur: IEEE Document complet vers site de l'éditeur
» An Inductive and Capacitive Integrated Coupler and Its LCL Compensation Circuit Design for Wireless Power Transfer
 Résumé:This paper proposes a novel coupler structure for wireless power transfer, which takes advantage of both magnetic and electric fields. The coupler contains four metal structures, two each at the primary and secondary sides, which are capacitively coupled. Each structure consists of long strips of metal sheet to increase its self-inductance, which is then inductively coupled with the other three structures. The structures are vertically arranged and the outer structures are larger than the inner ones to maintain the capacitive couplings. An external LCL compensation network is proposed to resonate with the coupler. The resonance provides conduction currents flowing through each plate to establish magnetic fields and displacement currents flowing between different plates corresponding to electric fields. A 100-W output power prototype is designed and implemented to operate at 1.0 MHz, and it achieves 73.6% efficiency from dc source to dc load across an air-gap distance of 18 mm. The contribution of this paper is to propose a concept to transfer power using magnetic and electric fields simultaneously. Auteurs: Fei Lu;Hua Zhang;Heath Hofmann;Chunting Chris Mi; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 4903 - 4913 Editeur: IEEE Document complet vers site de l'éditeur
» An Inductorless Bias-Flip Rectifier for Piezoelectric Energy Harvesting
 Résumé:Piezoelectric vibration energy harvesters have drawn much interest for powering self-sustained electronic devices. Furthermore, the continuous push toward miniaturization and higher levels of integration continues to form key drivers for autonomous sensor systems being developed as parts of the emerging Internet of Things (IoT) paradigm. The synchronized switch harvesting (SSH) on inductor and synchronous electrical charge extraction are two of the most efficient interface circuits for piezoelectric energy harvesters; however, inductors are indispensable components in these interfaces. The required inductor values can be up to 10 mH to achieve high efficiencies, which significantly increase overall system volume, counter to the requirement for miniaturized self-power systems for IoT. An inductorless bias-flip rectifier is proposed in this paper to perform residual charge inversion using capacitors instead of inductors. The voltage flip efficiency goes up to 80% while eight switched capacitors are employed. The proposed SSH on capacitors circuit is designed and fabricated in a 0.35- $\mu \text{m}$ CMOS process. The performance is experimentally measured and it shows a 9.7 $\times$ performance improvement compared with a full-bridge rectifier for the case of a 2.5-V open-circuit zero-peak voltage amplitude generated by the piezoelectric harvester. This performance improvement is higher than most of the reported state-of-the-art inductor-based interface circuits, while the proposed circuit has a significantly smaller overall volume enabling system miniaturization. Auteurs: Sijun Du;Ashwin A. Seshia; Apparue dans: IEEE Journal of Solid-State Circuits Date publication: 10.-2017, volume: 52, issue:10, pages: 2746 - 2757 Editeur: IEEE Document complet vers site de l'éditeur
» An Inertial-Aided Homography-Based Visual Servo Control Approach for (Almost) Fully Actuated Autonomous Underwater Vehicles
 Résumé:A nonlinear inertial-aided image-based visual servo control approach for the stabilization of (almost) fully actuated autonomous underwater vehicles (AUVs) is proposed. It makes use of the homography matrix between two images of a planar scene as feedback information while the system dynamics are exploited in a cascade manner in a control design: An outer-loop control defines a reference setpoint based on the homography matrix and an inner-loop control ensures the stabilization of the setpoint by assigning the thrust and torque controls. Unlike conventional solutions that only consider the system kinematics, the proposed control scheme is novel in considering the full system dynamics (incorporating all degrees of freedom, nonlinearities, and couplings, as well as interactions with the surrounding fluid) and in not requiring information of the relative depth and normal vector of the observed scene. Augmented with integral corrections, the proposed controller is robust with respect to model uncertainties and disturbances. The almost global asymptotic stability of the closed-loop system is demonstrated, which is the largest domain of attraction one can achieve by means of continuous feedback control. Simulation results illustrating these properties on a realistic AUV model subjected to a sea current are presented and finally experimental results on a real AUV are reported. Auteurs: Szymon Krupínski;Guillaume Allibert;Minh-Duc Hua;Tarek Hamel; Apparue dans: IEEE Transactions on Robotics Date publication: 10.-2017, volume: 33, issue:5, pages: 1041 - 1060 Editeur: IEEE Document complet vers site de l'éditeur
» An Information Theory-Based Scheme for Efficient Classification of Remote Sensing Data
 Résumé:Information theory has recently become an interesting topic in earth observation data management and analysis, since it can provide important information on hidden interactions and correlations among the considered data records. Although several methods have been proposed and implemented to efficiently extract a proper set of features and deliver accurate image investigation, classification, and segmentation, these architectures show drawbacks when the data sets are characterized by complex interactions among the samples. In this paper, a new approach based on information theory for automatic pattern recognition is introduced for accurate classification of remotely sensed data. Experimental results carried out on real data sets show the validity of the proposed approach. Auteurs: Andrea Marinoni;Gianni Cristian Iannelli;Paolo Gamba; Apparue dans: IEEE Transactions on Geoscience and Remote Sensing Date publication: 10.-2017, volume: 55, issue:10, pages: 5864 - 5876 Editeur: IEEE Document complet vers site de l'éditeur
» An Input–Output Framework for Submanifold Stabilization
 Résumé:We study submanifold stabilization problems from an input–output perspective, where plant and controller are relations on their sets of input–output signals. In contrast to the classical input–output approaches, we consider signals whose integral $p$-fold distance to a submanifold is finite. For feedback interconnections of relations on such signals, we develop a framework to show that the distance of the output of the plant to the desired submanifold remains bounded. Within this framework, we present a small-gain theorem, a feedback theorem for conic relations, and a feedback theorem for passive relations. We connect our findings to multiplier theory and present applications to synchronization and pattern generation. Auteurs: Jan Maximilian Montenbruck;Murat Arcak;Frank Allgöwer; Apparue dans: IEEE Transactions on Automatic Control Date publication: 10.-2017, volume: 62, issue:10, pages: 5170 - 5184 Editeur: IEEE Document complet vers site de l'éditeur
» An Interactive Fuzzy Physical Programming for Solving Multiobjective Skip Entry Problem
 Résumé:The multicriteria trajectory planning for space manoeuvre vehicle (SMV) is recognized as a challenging problem. Because of the nonlinearity and uncertainty in the dynamic model and even the objectives, it is hard for decision makers to balance all of the preference indices without violating strict path and box constraints. In this paper, to provide the designer an effective method and solve the trajectory hopping problem, an interactive fuzzy physical programming algorithm is introduced. A new multiobjective SMV optimal control problem is formulated and parameterized using an adaptive technique. By using the density function, the oscillations of the trajectory can be captured effectively. In addition, an interactive decision-making strategy is applied to modify the current designer's preferences during optimization process. Two realistic decision-making scenarios are conducted by using the proposed algorithm; Simulation results indicated that without driving objective functions out of the tolerable region, the proposed approach can have better performance in terms of the satisfactory degree compared with other approaches like traditional weighted-sum method, goal programming and fuzzy goal programming. Also, the results can satisfy the current preferences given by the decision makers. Therefore, the method is potentially feasible for solving multicriteria SMV trajectory planning problems. Auteurs: Runqi Chai;Al Savvaris;Antonios Tsourdos;Yuanqing Xia; Apparue dans: IEEE Transactions on Aerospace and Electronic Systems Date publication: 10.-2017, volume: 53, issue:5, pages: 2385 - 2398 Editeur: IEEE Document complet vers site de l'éditeur
» An Introduction to Goodness of Fit for PMU Parameter Estimation
 Résumé:It is posited that the process of measuring the various parameters that characterize a signal is equivalent to a fitting problem in mathematics. The equation being fit is a model based on the “physics” of the signal. The Fourier transform or rms calculations in a phasor measurement unit (PMU) furnish the values of the coefficients. Regardless of exactly how the measurement is made, a metric we define and call the goodness of fit allows the measuring system to comment on the match between the signal it is observing and the model. The metric is based on the residuals, the differences between the signal itself and the value calculated from the result of measurement. Results from real-word PMUs and real-world signals illustrate that the equation of the PMU is well solved during steady conditions. We examine the effect of a fault in the transmission system on the goodness-of-fit metric for a PMU. We also apply the metric to results from a microPMU in the distribution system. Auteurs: Artis Riepnieks;Harold Kirkham; Apparue dans: IEEE Transactions on Power Delivery Date publication: 10.-2017, volume: 32, issue:5, pages: 2238 - 2245 Editeur: IEEE Document complet vers site de l'éditeur
» An Investigation of Discharge Characteristics of an Electrothermal Pulsed Plasma Thruster
 Résumé:The capillary-based pulsed plasma thruster (PPT) has high-energy transfer efficiency, which provides potential to improve traditional PPT performance. In this paper, the discharge characteristics of a capillary-based PPT have been investigated. First, the typical process of voltage and current waveform is recognized. It is featured with a fast voltage drop (~25 ns) and a consequent damped sine wave oscillation discharge. Then based on the circuit analysis, the equivalent plasma resistance has been calculated. The current waveform is well fit with a linearly increasing resistance model. The influence of charging voltage has also been studied. The deposited energy increases while the transfer efficiency decreases with the increasing applied voltage. The cavity dimension has effects on the equivalent circuit parameters. The results show that longer cavity and smaller diameter lead to more deposited energy and higher transfer efficiency. The influence of voltage and capillary dimension on the mass shot characteristic has been discussed. Finally, the estimated impulse bit has been calculated and the impulse bit characteristics have been discussed. These results can contribute to the further optimization of PPT. Auteurs: Yanan Wang;Weidong Ding;Le Cheng;Jiaqi Yan;Zhichuang Li;Jiachen Wang;Yongsheng Wang; Apparue dans: IEEE Transactions on Plasma Science Date publication: 10.-2017, volume: 45, issue:10, pages: 2715 - 2724 Editeur: IEEE Document complet vers site de l'éditeur
» An LC-Compensated Electric Field Repeater for Long-Distance Capacitive Power Transfer
 Résumé:This paper proposes an LC-compensated electric field repeater to extend the transfer distance of a capacitive power transfer (CPT) system. The repeater contains two metal plates connected with an external capacitor and an external inductor. The plates are used to generate electric fields to transfer power. The external inductor and capacitor are used to resonate with the plates in order to increase the voltage levels. The repeater is placed between a transmitter and a receiver, which also contains metal plates compensated by an LC network. The repeater can increase the transfer distance of the CPT system without significantly influencing the system power and efficiency. In this paper, the capacitive coupler structure and dimensions are designed and simulated using Maxwell software. Considering all the capacitive coupling between plates, an equivalent circuit model is derived. The fundamental harmonics approximation method is used to analyze the working principle of the circuit. A 150 W input power CPT system is designed as an example to validate the proposed repeater structure and compensation circuit topology. The system can achieve an efficiency of 66.9% from dc source to dc load, when the transfer distance is 360 mm and the repeater is placed between the transmitter and the receiver. Auteurs: Hua Zhang;Fei Lu;Heath Hofmann;Weiguo Liu;Chunting Chris Mi; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 4914 - 4922 Editeur: IEEE Document complet vers site de l'éditeur
» An Online Monitoring System for Oil Immersed Power Transformer Based on SnO2 GC Detector With a New Quantification Approach
 Résumé:In this paper, an online monitoring system based on a SnO2 gas chromatographic detector for power transformer condition assessment is developed. For a quantitative analysis of feature gases dissolved in transformer oil, a mathematical model derived from the chemistry and semiconductor theory is proposed. On the basis of this, gas chromatography measurement module along with electronic controlling and data sampling system is designed and integrated. A series of repeatability test and quantitative analysis has been performed; the repeatability performance is excellent for given concentrations; the measurement accuracy based on the proposed mathematical model for the feature gases shows good suitability. Furthermore, the transformer diagnosis is performed for identifying fault types. The experimental and practical application results demonstrate the effectiveness of this system. Auteurs: Jingmin Fan;Feng Wang;Qiuqin Sun;Feng Bin;Huisheng Ye;Yuhan Liu; Apparue dans: IEEE Sensors Journal Date publication: 10.-2017, volume: 17, issue:20, pages: 6662 - 6671 Editeur: IEEE Document complet vers site de l'éditeur
» An Online Scalable Approach to Unified Multirobot Cooperative Localization and Object Tracking
 Résumé:In this paper, we present a unified approach for multi-robot cooperative simultaneous localization and object tracking based on particle filters. Our approach is scalable with respect to the number of robots in the team. We introduce a method that reduces, from an exponential to a linear growth, the space and computation time requirements with respect to the number of robots in order to maintain a given level of accuracy in the full-state estimation. Our method requires no increase in the number of particles with respect to the number of robots. However, in our method, each particle represents a full-state hypothesis, leading to the linear dependency on the number of robots of both space and time complexity. The derivation of the algorithm implementing our approach from a standard particle filter algorithm and its complexity analysis are presented. Through an extensive set of simulation experiments on a large number of randomized datasets, we demonstrate the correctness and efficacy of our approach. Through real robot experiments on a standardized open dataset of a team of four soccer-playing robots tracking a ball, we evaluate our method's estimation accuracy with respect to the ground truth values. Through comparisons with other methods based on 1) nonlinear least squares minimization and 2) joint extended Kalman filter, we further highlight our method's advantages. Finally, we also present a robustness test for our approach by evaluating it under scenarios of communication and vision failure in teammate robots. Auteurs: Aamir Ahmad;Guilherme Lawless;Pedro Lima; Apparue dans: IEEE Transactions on Robotics Date publication: 10.-2017, volume: 33, issue:5, pages: 1184 - 1199 Editeur: IEEE Document complet vers site de l'éditeur
» An Ultralow Power Time-Domain Temperature Sensor With Time-Domain Delta–Sigma TDC
 Résumé:Without using bipolar transistors, serially connected inverter cells generate clock delay according to temperature. The delay is compared with a reference clock to estimate the temperature. The proposed time-to-digital converter (TDC) structure is using a time-domain delta–sigma $(\Delta\Sigma)$ modulator. This type of TDC with $\Delta\Sigma$ modulator can achieve higher resolution by increasing the oversampling ratio, with the advantages of low area and low power consumption. To increase the accuracy by producing true temperature-independent time delay, an external reference clock is utilized, instead of temperature-independent inverter cells, for robust operations. The measured temperature sensors demonstrated a minimum power consumption of 480 nW and a resolution under 0.1 °C. The $3\sigma$ error of the sensor is ±0.99 °C over −20 °C–80 °C temperature range from ten-sample measurement results. The chip area is 0.089 mm2 using a Dongbu 0.18-$\mu\mbox{m}$ CMOS process. The conversion rate is 1.25 samples/s. Auteurs: Wonjong Song;Junan Lee;Nayeon Cho;Jinwook Burm; Apparue dans: IEEE Transactions on Circuits and Systems II: Express Briefs Date publication: 10.-2017, volume: 64, issue:10, pages: 1117 - 1121 Editeur: IEEE Document complet vers site de l'éditeur
» An Ultrawideband Conformal Capsule Antenna With Stable Impedance Matching
 Résumé:An ultrawideband conformal capsule slot antenna, which has a simple configuration and a stable impedance matching characteristic, is described in this paper. In the past, wideband outer-wall antennas have been proposed for capsule-type applications. However, this paper shows that the outer wall is not a good choice for placing capsule antennas, since such a choice exhibits a high specific absorption ratio, low gain, and low efficiency. Instead, the antenna proposed in this paper is conformal to the inner wall of a capsule shell, and it provides a wide impedance bandwidth ranging from 1.64 to 5.95 GHz (113.6%). Furthermore, the impedance matching remains stable even with a change in the operating environment. Since in a typical application scenario a capsule will move through the digestive system, and thus experience varying environments, a wide bandwidth and stable performance are both very desirable attributes of the antenna, whose design is discussed in this paper. Moreover, the proposed antenna continues to maintain a stable impedance match even when a battery is added inside the capsule, or when there is a change in the battery size and/or its position. Given these advantages, we argue that slot antennas are well suited for incorporation into capsule antennas for the present application. Auteurs: Zengdi Bao;Yong-Xin Guo;Raj Mittra; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 10.-2017, volume: 65, issue:10, pages: 5086 - 5094 Editeur: IEEE Document complet vers site de l'éditeur
» Analog Coded SoftCast: A Network Slice Design for Multimedia Broadcast/Multicast
 Résumé:This paper presents a network slice design for ultra high definition (UHD) video broadcast/multicast to achieve higher network efficiency and improved quality of experience (QoE). The proposed network slice design consists of a rateless source compression scheme and an analog-coded SoftCast scheme. The rateless Spinal code is adopted to compress the video source at content server and the compressed source is transmitted from content server across wireless core network to the base station. An a priori information-assisted Spinal decoder is designed to utilize the sparsity of bit planes for compression. In the analog-coded SoftCast scheme, we design a new chaotic function-based analog code with negligible power penalty for the generalized Gaussian-distributed source in SoftCast because the existing chaotic functions designed for uniformly distributed sources suffer from serious power penalty in SoftCast. We also design a maximum a posteriori probability decoding algorithm for the proposed analog code in order to exploit the statistics of video source as a priori information to improve the performance. The experimental results show that the proposed rateless code-based compression scheme achieves efficient compression and approaches the bound of binary erasure channel. In particular, the 1/2 analog-coded SoftCast has almost 2 dB gain over conventional SoftCast with two repetitions, and the 1/3 analog-coded SoftCast has almost 3 dB gain over conventional SoftCast with three repetitions. The system simulations for the broadcast system show higher network capacity and improved QoE in the proposed UHD slice, because the reconstructed video quality of each user is commensurate with its channel condition. Auteurs: Bin Tan;Jun Wu;Ying Li;Hao Cui;Wei Yu;Chang Wen Chen; Apparue dans: IEEE Transactions on Multimedia Date publication: 10.-2017, volume: 19, issue:10, pages: 2293 - 2306 Editeur: IEEE Document complet vers site de l'éditeur
» Analysis and Design of Bang-Bang PD-Based Phase Noise Filter
 Résumé:In this paper, we present a bang-bang phase detector (BBPD) and a delay-line frequency discriminator-based phase noise filter (PNF). With a larger phase detection gain, the BBPD-based PNF enhances the sensitivity by suppressing the charge pump noise. A time-amplifier and a five times voting machine are introduced together with the sense-amplifier-flip-flop to minimize the BBPD noise to make its effects negligible in the PNF sensitivity. At 1-MHz offset, the PNF demonstrates 15-dB phase noise suppression with −120.2-dBc/Hz sensitivity. Its phase noise suppression offset frequency is from 100 kHz to 8 MHz with 10–10.1-GHz input frequency range. The circuit is fabricated in a 65-nm CMOS technology, and dissipates 98-mW power. Auteurs: Tongning Hu;Shilei Hao;Qun Jane Gu; Apparue dans: IEEE Transactions on Circuits and Systems I: Regular Papers Date publication: 10.-2017, volume: 64, issue:10, pages: 2703 - 2713 Editeur: IEEE Document complet vers site de l'éditeur
» Analysis and Design of Closed-Loop Control of Electrolytic Capacitor-Less Six-Pulse DC Link Three-Phase Inverter
 Résumé:Three-phase inverters in uninterrupted power supply, electric vehicles, and hybrid electric vehicles use an intermediate dc-link electrolytic capacitor, which has reliability issues and is one prominent cause of inverter failure and limited life. The large volume of an electrolytic capacitor increases the size and cost of the system. Recent research on electrolytic capacitorless inverters using six-pulse modulation technique along with high-frequency power conversion has attempted to address this issue. However, closed-loop operation and control has some issues due to capacitorless dc-link. In this paper, closed-loop operation, design, and implementation of an electrolytic capacitorless inverter is presented. A proof-of-concept 1-kW hardware prototype has been built and tested in a laboratory under different loading conditions. In total, 98% rated efficiency of the inverter is obtained with total harmonic distortion within 2%. Transient results during start-up and load change are smooth, demonstrating safe operation of the inverter. Auteurs: Anirban Ghoshal;Xuewei Pan;Akshay K Rathore; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 4957 - 4964 Editeur: IEEE Document complet vers site de l'éditeur
» Analysis and Design of the Ladder Resonant Switched-Capacitor Converters for Regulated Output Voltage Applications
 Résumé:The traditional Ladder switched-capacitor converters have the issues of hard-switching operation and poor line regulation capability. By adding a resonant inductor and substituting a bulky capacitor bank with a small resonant capacitor, its resonant configuration can be obtained and the aforementioned issues could be solved. In addition, by operating the Ladder resonant switched-capacitor converters (RSCs) above the resonance, the optimized operation region is found and some transformational changes can be obtained: the transistors can be operated with zero voltage switching turn-on and diodes are zero current switching turned on/off; the line regulation range is increased significantly for regulated output voltage applications; the instability issue of transition between discontinuous current mode and continuous current mode can be avoided with closed loop; and the voltage/current stress of the resonant tank is reduced. Extensive analysis above and below the resonance is presented to reveal the converter operation modes, voltage-gain curves, output characteristics, and voltage/current stress of the resonant tank. A 3X Ladder RSC prototype for an electronic fuel injection application with maximum output voltage 150 V, maximum power 140 W and peak efficiency 97.6% was designed to be operating in the optimized operation region. The analysis is verified by experimental results. Auteurs: Shouxiang Li;Kang Xiangli;Yifei Zheng;Keyue Ma Smedley; Apparue dans: IEEE Transactions on Industrial Electronics Date publication: 10.-2017, volume: 64, issue:10, pages: 7769 - 7779 Editeur: IEEE Document complet vers site de l'éditeur
» Analysis of a Direct Antenna Modulation Transmitter for Wideband OOK With a Narrowband Antenna
 Résumé:The characteristics of a narrowband antenna transmitting a broadband on–off-keyed signal using direct antenna modulation (DAM) are studied. The DAM technique has previously been proposed to generate a broadband signal using a rapidly time-varying antenna, but the signals produced using this technique and its limitations are not well understood. In this paper, we quantitatively compare the performance of a DAM transmitter to a conventional time-invariant transmit antenna. We show that the fall time of an RF pulse produced with the DAM configuration is measurably shorter than with the conventional system; however, the pulse rise time using both systems is identical. The performance of each system is then analyzed in terms of the bit error rate over a simple point-to-point link using analytical models, numerical simulation, and measurement. DAM reduces the intersymbol interference (ISI) by reducing the discharging time; however, the overall performance remains similar to the conventional system because of their similar charging times. While the DAM configuration does radiate a qualitatively broader spectrum as observed in previous studies, this does not translate into quantitative improvement in the characteristics of a transmitted data signal. Auteurs: Shruti Srivastava;Jacob J. Adams; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 10.-2017, volume: 65, issue:10, pages: 4971 - 4979 Editeur: IEEE Document complet vers site de l'éditeur
» Analysis of Distribution Using Graphical Goodness of Fit for Airborne SAR Sea-Clutter Data
 Résumé:For radar target detection, the clutter distribution model needs to be identified first. The goodness of fit (GoF) between the original data and the assumed distribution can be used to choose the proper distribution model. Generally, the GoF is obtained using data histogram and theoretical distribution curve, and then the distribution model is judged via GoF. However, when the sample number is small, the histogram is rough and fluctuating, affecting the analysis of GoF. For the small sample, the graphical characteristic is obtained with the sample data to choose the most fitting distribution to the data in this paper. The graphical characteristic is acquired by a simpler process, that is, the original data are directly set as the test statistics, avoiding computing and sorting of other statistics. In this paper, the real airborne circular synthetic aperture radar data under different scan angles are analyzed using the GoF corresponding to histogram and graphical GoF, respectively. The results show that when the sea-clutter data histogram is close to two distributions, a more fitting distribution model may not be obtained by traditional GoF, but can be acquired by graphical representation. In addition, the sea data with different sight angles have different match properties. It is seen that the sea data are closer to the Rayleigh distribution in side-looking mode than that in big squint-angle mode, while the Weibull distribution and K distribution show equal fitting performance to sea clutter under variant radar sight angles. Auteurs: Zhihui Xin;Guisheng Liao;Zhiwei Yang;Yuhong Zhang;Hongxing Dang; Apparue dans: IEEE Transactions on Geoscience and Remote Sensing Date publication: 10.-2017, volume: 55, issue:10, pages: 5719 - 5728 Editeur: IEEE Document complet vers site de l'éditeur
» Analysis of Leakage Loss in Silicon Photonics with Finite Gain Compensation
 Résumé:Silicon waveguides fabricated on silicon-on-insulator wafers are leaky in nature. This fact puts a lower bound on the insulator thickness in silicon photonic structures as integrated with compact electronic devices. We examine this constraint from the angle of finite gain compensation for leakage loss using III-V semiconductor gain media bonded to passive silicon waveguides. With a reasonable magnitude of available gain, we find that an insulator layer thinner than 320 nm could support the fundamental quasi-transverse-electric mode of silicon waveguides with a core thickness around 170 nm. This may enable the integration of photonic devices with compact electronic counterparts for radio-frequency and analog applications. Furthermore. size reductions to the level of partially depleted electronic devices might be possible if the leakage loss need not be fully compensated, or the gain limit could be raised Auteurs: Po-Jui Chiang;Tien-Tsorng Shih; Apparue dans: IEEE Photonics Journal Date publication: 10.-2017, volume: 9, issue:5, pages: 1 - 10 Editeur: IEEE Document complet vers site de l'éditeur
» Analysis of Path-Length Effects in Multiloop Cross-Eye Jamming
 Résumé:The effect of path-length differences on multiloop retrodirective cross-eye jammers is evaluated. It is shown that such jammers may act as beacons, and the conditions under which this occurs are investigated for two-loop jammers. The sensitivity of the two-loop cross-eye gain to path-length differences is also studied and is found to be small for small path-length differences, but to increase rapidly. The effect of the two-loop cross-eye jammer parameters on path-length effects is also considered. Auteurs: Warren Paul du Plessis; Apparue dans: IEEE Transactions on Aerospace and Electronic Systems Date publication: 10.-2017, volume: 53, issue:5, pages: 2266 - 2276 Editeur: IEEE Document complet vers site de l'éditeur
» Analysis of Performance Optimization for a Microwave Photonic Filter Based on Stimulated Brillouin Scattering
 Résumé:A single passband microwave photonic filter (MPF) based on stimulated Brillouin scattering (SBS) is analyzed and experimentally demonstrated. The proposed MPF can be tuned over a dramatically large frequency range, which overcomes the disadvantage in previously reported schemes based on SBS that the frequency tuning range is limited within two folds of the Brillouin frequency shift. The single passband MPF is obtained by enhancing the amplitude of the microwave passband generated by SBS gain while suppressing the amplitude of the microwave passband generated by SBS loss through optimizing the key parameters of the SBS process, including the pump power, the length of high nonlinear fiber, and the polarization states of the pump and signal waves. A theoretical model is established to describe the operation principle of the SBS-based MPF and illustrate the mechanism for the single passband, and an experiment is carried out to verify the theoretical analysis. In the experiment, the central frequency of the single passband MPF can be tuned from 0 to 40 GHz, which is only limited by the bandwidth of the adopted electro-optic modulator and photodetector. The main to secondary sidelobe ratio can reach 55 dB and the full width at half-maximum bandwidth is 16 MHz. The achieved MPF is specifically suitable for applications in ultrahigh selective filtering. Auteurs: Haitao Tang;Yuan Yu;Chi Zhang;Ziwei Wang;Lu Xu;Xinliang Zhang; Apparue dans: Journal of Lightwave Technology Date publication: 10.-2017, volume: 35, issue:20, pages: 4375 - 4383 Editeur: IEEE Document complet vers site de l'éditeur
» Analysis of PM Transverse-Flux Outer Rotor Machines With Different Configuration
 Résumé:This paper presents the electromagnetic analysis of two permanent magnet transverse-flux outer rotor machines with and without magnetic shunts. The research started with designing and analyzing a permanent magnet transverse-flux machine with an inner rotor, previously patented by J. Giearas in 2010. However, the results obtained from the prototype test differed significantly from the estimated results. Applying three-dimensional (3-D) finite element method (FEM), the main problem of the machine was detected. The problem was in high flux leakage that weakened magnetic flux density in the stator poles. Such observation led to designing two machines with outer rotor, with and without magnetic shunts. The role of the magnetic shunts is to minimize flux leakage in the stator in order to improve the performance of the machine. Electromechanical parameters of both outer rotor machines, with and without magnetic shunts, are compared in the paper. Three-D FEM results are supported by laboratory analysis of the machines’ prototypes. Experimental measurements proved that the machine with magnetic shunts demonstrated better performance as compared with the machine without magnetic shunts. Presence of the magnetic shunts in the machine resulted in reducing of flux leakage and cogging torque. Auteurs: Oleksandr Dobzhanskyi;Rupert Gouws;Ebrahim Amiri; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 4260 - 4268 Editeur: IEEE Document complet vers site de l'éditeur
» Analysis of Temperature Effects on Performance of Interior Permanent Magnet Machines for High Variable Temperature Applications
 Résumé:The purpose of this paper is to analyze and investigate the influence of temperature variation on the characteristics and performance of interior permanent magnet (IPM) machines. The impact of temperature variation on the materials of IPM machines is discussed to show the sources of performance variation. The flux linkages, torque output capability, and inductance variation as functions of the temperature are analyzed and discussed. This paper also shows the influence of temperature variation on key IPM machines performance including constant torque curves, voltage limit ellipses, maximum torque per ampere trajectories, and torque–speed curves. Experimental results of a traction IPM machine verified the analysis and theory. The results and trends shown in this paper set a foundation for developing control algorithm, which takes the temperature effects into consideration, especially in the applications where operating temperature varies significantly. Auteurs: Silong Li;Bulent Sarlioglu;Sinisa Jurkovic;Nitin R. Patel;Peter Savagian; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 4923 - 4933 Editeur: IEEE Document complet vers site de l'éditeur
» Analytical Formulas for Artificial Dielectrics With Nonaligned Layers
 Résumé:In this paper, we present analytical models to describe artificial dielectric layers (ADLs), when a lateral shift between layers is present. The alternate lateral displacement between layers is an important parameter to engineer the desired effective electromagnetic properties of the equivalent homogeneous material realized with the ADLs. More specifically, the equivalent dielectric constants that can be realized by alternatively shifting the layers are higher compared with the aligned case. Closed-form expressions are derived for the equivalent layer reactance that includes the higher order interaction between shifted layers. The given analytical formulas can be used to derive an equivalent circuit model that describes the scattering parameters of a plane wave impinging on a slab composed by an arbitrary finite number of metal layers. To aid the design of artificial dielectric slabs, the effective permittivity and permeability tensors are also retrieved from the scattering parameters. Auteurs: Daniele Cavallo;Cantika Felita; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 10.-2017, volume: 65, issue:10, pages: 5303 - 5311 Editeur: IEEE Document complet vers site de l'éditeur
» Analytical Insights Into Parameter Estimation for Wiener Deconvolution
 Résumé:All real-time signals observed from various measurement systems require signal-processing techniques like the deconvolution, to compensate for the effect of transfer function of the systems. Wiener deconvolution is a widely used signal-processing technique for signal restoration. Often, if the power spectral density of signal and noise is unknown, the accuracy of the restored signal depends on an unknown filter parameter. In the literature, time-consuming, iterative, computational methods were reported to estimate the parameter. However, many of these methods give a range of optimum values instead of an unique value and often lead to either over-smoothing or under-smoothing. In this paper, novel analytical expressions are presented through which the unknown parameter can be estimated explicitly. The analytical results of this study are compared with the numerical methods, and they are found to be accurate and robust against numerical evaluation. Further, the results are demonstrated for signals obtained experimentally from the pulsed electroacoustic system and a network, in authors’ laboratory. Auteurs: Ashish Gupta;Chandupatla Chakradhar Reddy; Apparue dans: IEEE Transactions on Instrumentation and Measurement Date publication: 10.-2017, volume: 66, issue:10, pages: 2566 - 2575 Editeur: IEEE Document complet vers site de l'éditeur
» Analytical Modeling of Mutually Coupled Switched Reluctance Machines Under Saturation Based on Design Geometry
 Résumé:An analytical calculation of the winding flux linkages and torque is proposed for fully pitched mutual coupled switched reluctance motors to develop a machine model without using numerical methods. The proposed technique is not empirical and does not require any finite-element analysis (FEA). The design parameters and the material properties of the machine are the only inputs to the model, which can predict the winding flux linkages and torque at any phase currents and rotor positions. The model is applicable for the rotor positions where the stator and rotor poles overlap. Initial assumptions and then the step-by-step procedure for flux linkage, co-energy, and torque calculations are provided. The flux linkages and torque predicted through the proposed modeling technique are compared with the FEA results. Finally, experimental results of flux linkage and torque are provided to verify the accuracy of the proposed modeling technique. Auteurs: Wasi Uddin;Yilmaz Sozer; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 4431 - 4440 Editeur: IEEE Document complet vers site de l'éditeur
» Analyzing Graphene-Based Absorber by Using the WCS-FDTD Method
 Résumé:A weakly conditionally stable finite-difference time-domain (WCS-FDTD) method is used to simulate a graphene-based absorber. By using the auxiliary differential equation and Padé fitting method, both the interband and intraband conductivities of the graphene are incorporated into the WCS-FDTD method. The time step increment in the proposed method is not determined by the fine meshes in the graphene layer, so the computational efficiency of this method is greatly improved from that of the conventional FDTD method. By using the proposed WCS-FDTD method, a graphene-based absorber is simulated and analyzed. The numerical result shows that the graphene can achieve tunable absorption through controlling its chemical potential, and the interband conductivity of the graphene has important effects on the performance of the absorber. Auteurs: Juan Chen;Jianxing Li;Qing Huo Liu; Apparue dans: IEEE Transactions on Microwave Theory and Techniques Date publication: 10.-2017, volume: 65, issue:10, pages: 3689 - 3696 Editeur: IEEE Document complet vers site de l'éditeur
» Analyzing the Stability of Switched Systems Using Common Zeroing-Output Systems
 Résumé:This paper introduces the notion of common zeroing-output systems (CZOS) to analyze the stability of switched systems. The concept of CZOS allows one to verify weak zero-state detectability. It characterizes a common behavior of any individual subsystem when the output signal for each subsystem is “approaching” zero. Heuristically speaking, it removes the effect of switching behavior, and thus enables one to analyze stability properties in systems with complex switching signals. With the help of CZOS, the Krasovskii–LaSalle theorem can be extended to switched nonlinear time-varying systems with both arbitrary switching and more general restricted switching cases. For switched nonlinear time-invariant systems, the needed detectability condition is further simplified, leading to several new stability results. Particularly, when a switched linear time-invariant system is considered, it is possible to generate a recursive method, which combines a Krasovskii–LaSalle result and a nested Matrosov result, to find a CZOS if it exists. The power of the proposed CZOS is demonstrated by consensus problems in literature to obtain a stronger convergence result with weaker conditions. Auteurs: Ti-Chung Lee;Ying Tan;Iven Mareels; Apparue dans: IEEE Transactions on Automatic Control Date publication: 10.-2017, volume: 62, issue:10, pages: 5138 - 5153 Editeur: IEEE Document complet vers site de l'éditeur
» Angle Domain Hybrid Precoding and Channel Tracking for Millimeter Wave Massive MIMO Systems
 Résumé:The millimeter-wave (mm-wave) massive multiple-input multiple-output (MIMO) system has gained much attention for its considerable improvement in system throughput. However, the cost of complex hardware, e.g., radio frequency (RF) chains, hinders it from practical deployment. In this paper, we propose an angle domain hybrid precoding and channel tracking method by exploring the spatial features of the mm-wave massive MIMO channel. The number of the effective spatial beams, or equivalently the RF chains, is enormously decreased via the operation of spatial rotation. The users are then scheduled by the angle division multiple access scheme, which groups users according to their direction of arrivals (DOAs). Meanwhile, a channel tracking method is designed for the subsequent data transmission through a small number of pilot symbols. Specifically, the channel information is divided into the DOA information and the gain information, where the DOA information is tracked by a modified unscented Kalman filter and the gain information is estimated from beam training. Numerical results are provided to corroborate our studies. Auteurs: Jianwei Zhao;Feifei Gao;Weimin Jia;Shun Zhang;Shi Jin;Hai Lin; Apparue dans: IEEE Transactions on Wireless Communications Date publication: 10.-2017, volume: 16, issue:10, pages: 6868 - 6880 Editeur: IEEE Document complet vers site de l'éditeur
» Anisotropic Discrete Dual-Tree Wavelet Transform for Improved Classification of Trabecular Bone
 Résumé:This paper deals with a new anisotropic discrete dual-tree wavelet transform (ADDTWT) to characterize the anisotropy of bone texture. More specifically, we propose to extend the conventional discrete dual-tree wavelet transform (DDTWT) by using the anisotropic basis functions associated with the hyperbolic wavelet transform instead of isotropic spectrum supports. A texture classification framework is adopted to assess the performance of the proposed transform. The generalized Gaussian distribution is used to model the distribution of the sub-band coefficients. The estimated vector of parameters for each image is then used as input for the support vector machine classifier. Experiments were conducted on synthesized anisotropic fractional Brownian motion fields and on a real database composed of osteoporotic patients and control cases. Results show that the ADDTWT outperforms most of the competing anisotropic transforms with an area under curve rate of 93%. Auteurs: Hind Oulhaj;Mohammed Rziza;Aouatif Amine;Hechmi Toumi;Eric Lespessailles;Mohammed El Hassouni;Rachid Jennane; Apparue dans: IEEE Transactions on Medical Imaging Date publication: 10.-2017, volume: 36, issue:10, pages: 2077 - 2086 Editeur: IEEE Document complet vers site de l'éditeur
» Antenna Deembedding for mmWave Propagation Modeling and Field Measurement Validation at 73 GHz
 Résumé:In field measurements at millimeter-wave (mmWave) frequencies, the spatial propagation characteristics are usually obtained by using steerable high-gain horn antennas to compensate the large path loss. However, it is a challenging issue to deembed antenna patterns from the observed channel responses. This paper has two contributions. First, according to the steering-antenna sounding process, a spatial channel response model is designed, where the multipath propagation profile, antenna pattern, and channel response are spatially sampled and combined in a discrete convolutional form. Then, a low-complexity antenna deembedding algorithm, including two steps of deconvolutions, is proposed. Second, a field measurement campaign on the frequency-space mmWave channels in an office is presented to validate the method. The channels were sounded at 72.5 to 73.5 GHz using three horn antennas with different beam widths and gains. The omnidirectional angular channel responses (ACRs) were measured by rotating the receiver antenna. The observed and reconstructed ACRs are consistent, and the estimated antenna-free angular propagation profiles by using different horn antennas are also highly correlated, which validate the proposed antenna deembedding approach. Furthermore, the omnidirectional transfer functions in the mmWave band obtained using different horn antennas are compared, and the channel coherence bandwidth is analyzed based on the autocorrelation of the transfer functions. Auteurs: Ruonan Zhang;Yuliang Zhou;Xiaofeng Lu;Chang Cao;Qi Guo; Apparue dans: IEEE Transactions on Microwave Theory and Techniques Date publication: 10.-2017, volume: 65, issue:10, pages: 3648 - 3659 Editeur: IEEE Document complet vers site de l'éditeur
» Anti-Islanding Protection Relay for Medium Voltage Feeder With Multiple Distributed Generators
 Résumé:Large distributed generators (DGs) are usually connected to medium voltage (MV, typically up to 50 kV) feeders directly. Their anti-islanding protections mainly rely on transfer trips from upstream substations through communication media, which are expensive and time-consuming because of infrastructure. This paper presents a local anti-islanding protection relay (LPR) as an alternative for the traditional transfer trip in MV feeder applications. The basic idea of the proposed LPR is to short phase to neutral or phase to phase voltages by thyristors at the point of common coupling (PCC) of each DG when either of them is crossing zero; then both variations of the thyristor current and voltage harmonic distortion at the PCC are observed and measured, and they are able to indicate the operating mode of the DG unit in either grid-connected or islanding. Further, this approach is analyzed and discussed based on a single DG scenario and a complicated scenario with two DGs and one shunt capacitor bank. Finally, a lot of experiment results with different scenarios are obtained based on a scale-down testing platform, which has been built in our lab by using per-unit method from an actual MV feeder system. Auteurs: Hua F. Xiao;Zhijian Fang;Dewei Xu;Bala Venkatesh;Birendra Singh; Apparue dans: IEEE Transactions on Industrial Electronics Date publication: 10.-2017, volume: 64, issue:10, pages: 7874 - 7885 Editeur: IEEE Document complet vers site de l'éditeur
» Aperture Distributions for Maximum Endfire Directivity From a Continuous Line Source With a Uniform Phase Progression
 Résumé:An optimized aperture distribution is investigated to achieve the maximum endfire directivity for a continuous line source with a uniform phase progression. The optimization method has the advantages of simplicity and efficiency, in which the aperture distribution is expanded into a set of cosine functions and the optimization reduces to solving a constrained linear-least-squares problem. Based on the copious computed results from the optimization, an approximate closed-form expression is derived for the maximum directivity. The expression can serve as a bound for the endfire directivity for a line source with a uniform phase progression. It is found that the optimum directivity increases almost linearly with an increase of the normalized phase constant, but with a decrease in the radiated power. Nevertheless, the enhancement in the directivity is much higher than that in previously studied superdirectivity, under the same constraint in the ratio of reactive to radiated power. The current distribution does not oscillate widely as is does for superdirectivity, and is therefore more practical than for superdirectivity. Auteurs: Juhua Liu;David R. Jackson; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 10.-2017, volume: 65, issue:10, pages: 5123 - 5136 Editeur: IEEE Document complet vers site de l'éditeur
» Applicability of LED-Based Excitation Source for Defect Depth Resolved Frequency Modulated Thermal Wave Imaging
 Résumé:This paper proposes an energy efficient instrumentation set-up for pulse-compression thermal-wave imaging with a low-power LED excitation source. The set-up consists of three different subsystems that are synchronised in time. The individual systems consist of a LED modulation circuitry, reference signal measurement circuitry, and an IR camera trigger signal generation circuitry for frame capture. A separate reference acquisition circuitry is useful in quantifying defect depth resolution. This paper also proposes a nonuniform frame capture technique to reduce the memory allocation space of the recorded video. The technique is based on varying the sampling rate with a change in instantaneous frequency and is specifically useful for frequency modulated excitation signal. The proposed technique is implemented on a carbon fiber reinforced polymer test-piece. The variation of pulse compression parameters with different defect dimension is studied, and the results are verified with an electro-thermal simulator. Further, an objective comparison of pulse compression experiment for different experiment duration is presented. Auteurs: Deboshree Roy;Suneet Tuli; Apparue dans: IEEE Transactions on Instrumentation and Measurement Date publication: 10.-2017, volume: 66, issue:10, pages: 2658 - 2665 Editeur: IEEE Document complet vers site de l'éditeur
» Application of the Curvelet Transform for Clutter and Noise Removal in GPR Data
 Résumé:This paper presents a new method based on the curvelet transform to improve the readability of ground penetrating radar (GPR) data during localization works of buried pipes. The localization is achieved by the detection of hyperbolas in the GPR cross section, also called B-scan. However, GPR antenna collects abundant information from the ground, which can partially hide useful information, especially echoes from the pipes (i.e., hyperbolas). In order to highlight these echoes, it is important to reduce noise and to remove undesirable items such as the clutter and column artifacts. For this purpose, we propose to use the curvelet transform in a three processing step method: clutter, noise, and column artifact removal. Thanks to prior information on the distribution of the coefficients and on the orientation of the clutter and artifacts, we are able to reduce them in the B-scan. These steps can be used independently giving more flexibility to the operator. Moreover, the processing is fast to compute and requires only one easily tunable parameter. This is appropriate for a computation in real-time by nonexpert operators. Our method has been applied to real data acquired on a test area and under real conditions. We show the proposed method presents satisfying qualitative and quantitative results compared to other methods. Auteurs: Guillaume Terrasse;Jean-Marie Nicolas;Emmanuel Trouvé;Émeline Drouet; Apparue dans: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing Date publication: 10.-2017, volume: 10, issue:10, pages: 4280 - 4294 Editeur: IEEE Document complet vers site de l'éditeur
» Applying Transmission Line Theory to Study the Transmitting Turn-OFF Current in a Long Grounded Wire
 Résumé:A long grounded wire in the transient electromagnetic (TEM) surveys is usually considered by using the lumped parameter circuit model, which fails to explicate the early turn-OFF current with crucial importance for TEM surveys. In this paper, the transmission line model is introduced for the first time to explicate the early turn-OFF current in the long grounded wire considering the high frequency at early turn-OFF stage. The transmission line model suitable for the long grounded wire is constructed, then the calculation formulas of the distributed parameters and load impedance are analyzed, and the transfer function utilized to simulate the current at any position of the transmission line is also derived. The simulation is performed in the frequency domain with subsequent transformation into the time domain, and the simulation results are in good agreement with the experimental data. The early turn-OFF currents depending on the earth resistivity vary with the position in the long grounded wire. Therefore, the early time TEM response differs from that predicted by the classical theory of the TEM surveys. This proposed model can guide the realization of the minimum current turn-OFF duration, which will help to reduce the detection blind spot and this paper provides new ideas and prospects for early response data and current waveform data for interpretation in the geophysics detection. Auteurs: Zongyang Shi;Lihua Liu;Pan Xiao;Zhi Geng;Guangyou Fang; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 10.-2017, volume: 65, issue:10, pages: 5112 - 5122 Editeur: IEEE Document complet vers site de l'éditeur
» Approximate Mean Delay Analysis for a Signalized Intersection With Indisciplined Traffic
 Résumé:Mixed vehicular traffic comprising small cars and two-wheeled vehicles (called motorcycles in this paper) arrive at a lane of a signalized road intersection. The traffic does not follow lane-discipline, in that the arriving vehicles do not necessarily queue up one behind the other. The motorcycles are small enough to stand side-by-side with cars or other motorcycles, so as to fill up the width of the lane. With such queue joining behavior, the waiting vehicles form batches, comprising motorcycles, and at most one car. During the green signal period the vehicles in the head-of-the-line batch exit the intersection together. In this paper, assuming a Poisson point process model for vehicle arrivals, we have provided an approximate analysis of such a queueing system. Our approach is to use an assembly queue model for the batching process. The batches generated by the assembly queue enter an interrupted M/SemiMarkov/1 (or M/SM/1) queue. By analyzing the assembly queue we characterize the batch input process for the interrupted M/SM/1 queue. We then develop an extension of the Webster mean delay formula for obtaining the approximate mean delay in the interrupted M/SM/1 queue. Numerical results from the analysis are compared with simulation results. The analysis is shown to be accurate in predicting the increase in the system capacity due to the batching behavior. Auteurs: Samrat Mukhopadhyay;Pramod M. J.;Anurag Kumar; Apparue dans: IEEE Transactions on Intelligent Transportation Systems Date publication: 10.-2017, volume: 18, issue:10, pages: 2750 - 2762 Editeur: IEEE Document complet vers site de l'éditeur
» Arc Flash Visible Light Intensity as Viewed From Human Eyes
 Résumé:Human eye can be damaged by the intense light from an arc flash event. Though it is certain that high intensity visible light will be emitted during an arc flash event, there is limited research that provides quantitative light intensity estimation during different arcing incidents as viewed from human eyes. To provide better understanding of the light intensity during arc flash events, this paper proposes an arc flash light intensity estimation model based on approximately 1500 measurement data from arc flash tests using ambient light sensors, which are capable of measuring the light intensity of the arc flash as perceived by the human eyes. The proposed light intensity estimation model can be used to evaluate the potential impact of an arc flash on the human eyes. In addition, the autodarkening welding lens is used in the arc flash testing to explore its effectiveness in attenuating the light intensity and mitigating the exposure to the light hazard during an arc flash event. Auteurs: Shiuan-Hau Rau;Zhenyuan Zhang;Wei-Jen Lee;David A. Dini; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 5068 - 5077 Editeur: IEEE Document complet vers site de l'éditeur
» Architecture Design of a Memory Subsystem for Massive MIMO Baseband Processing
 Résumé:This brief presents an on-chip memory subsystem for massive multiple-input-multiple-output (MIMO) baseband processing at the base station. In massive MIMO systems, the required memory bandwidth and capacity are orders of magnitude higher than those used in conventional wireless systems, due to the large number of serving antennas. These are further combined with design targets on low access latency and flexibility in data organization and access modes. This brief applies and improves the concept of parallel memories to achieve the challenging design target with low hardware overhead. As a case study, a memory subsystem for 128-antenna and 16-user massive MIMO systems is evaluated using ST 28-nm technology. According to postlayout simulation results, the proposed memory subsystem provides 512-Gb/s throughput and offers 1-Mb capacity with a cost of 0.30 mm2. Auteurs: Yangxurui Liu;Liang Liu;Viktor Öwall; Apparue dans: IEEE Transactions on Very Large Scale Integration Systems Date publication: 10.-2017, volume: 25, issue:10, pages: 2976 - 2980 Editeur: IEEE Document complet vers site de l'éditeur
» ARCNET Never Received Enough Credit [History]
 Résumé:In the March 2017 issue of IEEE Industrial Electronics Magazine, the authors of "The Future of Industrial Communication" provided a comprehensive chart of industrial communication milestones ranging from the 1960s to the present [1]. But there was one glaring omission-the Attached Resource Computer Network (ARCNET). As a former chair of the ARCNET Trade Association (ATA), I feel obligated to defend ARCNET as the first local area network (LAN), which is still in use today [2]. It is a technology that impacted both the office and industrial automation industries. It is elegant, fast, robust-and it works! The technology was deemed by the press as "the Rodney Dangerfield of network computing," and its proponents were called fanatical [3]. Although ARCNET has failed to receive the recognition it deserves, it is a successful technology that has been used in applications never imagined by its creators. Auteurs: George Thomas; Apparue dans: IEEE Industry Applications Magazine Date publication: 10.-2017, volume: 23, issue:5, pages: 7 - 13 Editeur: IEEE Document complet vers site de l'éditeur
» Area/Energy-Efficient Gammatone Filters Based on Stochastic Computation
 Résumé:This paper introduces area/energy-efficient gammatone filters based on stochastic computation. The gammatone filter well expresses the performance of human auditory peripheral mechanism and has a potential of improving advanced speech communications systems, especially hearing assisting devices and noise robust speech-recognition systems. Using stochastic computation, a power-and-area hungry multiplier used in a digital filter is replaced by a simple logic gate, leading to area-efficient hardware. However, a straightforward implementation of the stochastic gammatone filter suffers from significantly low accuracy in computation, which results in a low dynamic range (a ratio of the maximum to minimum magnitude) due to a small value of a filter gain. To improve the computation accuracy, gain-balancing techniques are presented that represent the original gain as the product of multiple larger gains introduced at the second-order sections. In addition, dynamic scaling techniques are proposed that scales up small values only on stochastic domain in order to reduce the number of stochastic bits required while maintaining the computation accuracy. For performance comparisons, the proposed stochastic gammatone filters are designed and evaluated on taiwan semiconductor manufacturing company (TSMC) 65-nm CMOS technology. As a result, the proposed filter achieves an area reduction of 90.7% and an energy reduction of 91.8% in comparison with a fixed-point gammatone filter at the same sampling frequency and a comparable dynamic range. Auteurs: Naoya Onizawa;Shunsuke Koshita;Shuichi Sakamoto;Masahide Abe;Masayuki Kawamata;Takahiro Hanyu; Apparue dans: IEEE Transactions on Very Large Scale Integration Systems Date publication: 10.-2017, volume: 25, issue:10, pages: 2724 - 2735 Editeur: IEEE Document complet vers site de l'éditeur
» Assessment of the Influence of Losses on the Performance of the Electromagnetic Time Reversal Fault Location Method
 Résumé:Electromagnetic time reversal (EMTR) has been shown to be an efficient method for locating faults in ac and dc power grids. In the available literature, the back-propagation medium has been considered to have identical losses as the directtime medium. However, the telegrapher's equations describing the traveling wave propagation are time-reversal invariant if and only if inverted losses are considered in the back-propagation phase. This paper presents an analysis of the impact of losses on the performance of the EMTR-based fault location method for power networks. In this respect, three back-propagation models are proposed, analyzed, and compared. It is shown that a lossy back-propagation model, for which the wave equations are not rigorously time-reversal invariant, results in accurate fault locations. Finally, an EMTR fault location system based on the lossy back-propagation model and a fast electromagnetic transient simulation platform is developed and its performances validated. Auteurs: Reza Razzaghi;Gaspard Lugrin;Farhad Rachidi;Mario Paolone; Apparue dans: IEEE Transactions on Power Delivery Date publication: 10.-2017, volume: 32, issue:5, pages: 2303 - 2312 Editeur: IEEE Document complet vers site de l'éditeur
» Asynchronous Multirate Multisensor Data Fusion Over Unreliable Measurements With Correlated Noise
 Résumé:In this paper, the problem of optimal state estimation is studied for fusion of asynchronous multirate multiscale sensors with unreliable measurements and correlated noise. The noise of different sensors is cross-correlated and coupled with the system noise of the previous step and the same time step. The system is described at the highest sampling rate with different sensors observing a single target independently with multiple sampling rates. An optimal state estimation algorithm based on iterative estimation of the white noise estimator is presented, which makes full use of the observation information effectively, overcomes the packet loss, data fault, unreliable factors, and improves the precision and the robustness of the system state estimation. A numerical example is used to illustrate the effectiveness of the presented algorithm. Auteurs: Lu Jiang;Liping Yan;Yuanqing Xia;Qiao Guo;Mengyin Fu;Kunfeng Lu; Apparue dans: IEEE Transactions on Aerospace and Electronic Systems Date publication: 10.-2017, volume: 53, issue:5, pages: 2427 - 2437 Editeur: IEEE Document complet vers site de l'éditeur
» Asynchronous Physical-Layer Network Coding: Symbol Misalignment Estimation and Its Effect on Decoding
 Résumé:In asynchronous physical-layer network coding (APNC) systems, the symbols from multiple transmitters to a common receiver may be misaligned. Knowledge of the amount of symbol misalignment, hence its estimation, is important to PNC decoding. This paper addresses the problems of symbol-misalignment estimation and optimal PNC decoding given the misalignment estimate, assuming the APNC system uses the root-raised-cosine pulse to carry signals (RRC-APNC). Our contributions are as follows. First, we put forth an optimal symbol-misalignment estimator that makes use of double baud-rate samples. Second, we devise optimal RRC-APNC decoders in the presence of non-exact symbol-misalignment estimates. In particular, we show how to whiten the colored noise in the double baud-rate samples to simplify the design of optimal decoders. Third, we investigate the decoding performance of various estimation-and-decoding schemes for RRC-APNC. Extensive simulations show that: 1) our double baud-rate estimator yields substantially more accurate symbol-misalignment estimates than the baud-rate estimator does; the mean square error gains are up to 8 dB and 2) an overall estimation-and-decoding scheme in which both estimation and decoding are based on double baud-rate samples yields much better performance than other schemes. Compared with a scheme in which both estimation and decoding are based on baud-rate samples, the double baud-rate sampling scheme yields 4.5 dB gains on symbol error rate performance in an additive white Gaussian noise channel, and 2 dB gains on packet error rate performance in a Rayleigh fading channel. Auteurs: Yulin Shao;Soung Chang Liew;Lu Lu; Apparue dans: IEEE Transactions on Wireless Communications Date publication: 10.-2017, volume: 16, issue:10, pages: 6881 - 6894 Editeur: IEEE Document complet vers site de l'éditeur
» Audible Noise Characteristics of Filter Capacitors Used in HVDC Converter Stations
 Résumé:This paper presents a detailed investigation of audible noise characterization of filter capacitors by investigating the noise radiation characteristics and analyzing the effect of voltage frequency, phase angle, and magnitude on a single capacitor unit. First, the noise radiation for capacitor surfaces was characterized theoretically using finite rectangular plate model and experimentally measured in a semianechoic room. Second, voltage frequency impact on the noise distribution was investigated through simulation. The simulation results show that noise directivity increases with increasing frequency. The excitation frequency impact on the radiation ratio and the noise level was characterized through a sweep-frequency experiment. Our investigations show that the noise frequency response below 500 Hz is quite low, while from 500 to 2000 Hz, it is significant and increases slowly. Third, the impact of the voltage phase angle on the noise level was investigated. The results show a noise-level difference of 3.9 dB for different phase angles. Finally, we present the voltage magnitude impact on the noise level. Our theoretical analysis and experimental study show a linear relationship between the sound power level and the logarithm of the voltage magnitude with a slope of 40. Auteurs: Lingyu Zhu;Jinyu Li;Yuhang Shi;Habibur Rehman;Shengchang Ji; Apparue dans: IEEE Transactions on Power Delivery Date publication: 10.-2017, volume: 32, issue:5, pages: 2263 - 2271 Editeur: IEEE Document complet vers site de l'éditeur
» Augmented Reality Marker Hiding with Texture Deformation
 Résumé:Augmented reality (AR) marker hiding is a technique to visually remove AR markers in a real-time video stream. A conventional approach transforms a background image with a homography matrix calculated on the basis of a camera pose and overlays the transformed image on an AR marker region in a real-time frame, assuming that the AR marker is on a planar surface. However, this approach may cause discontinuities in textures around the boundary between the marker and its surrounding area when the planar surface assumption is not satisfied. This paper proposes a method for AR marker hiding without discontinuities around texture boundaries even under nonplanar background geometry without measuring it. For doing this, our method estimates the dense motion in the marker’s background by analyzing the motion of sparse feature points around it, together with a smooth motion assumption, and deforms the background image according to it. Our experiments demonstrate the effectiveness of the proposed method in various environments with different background geometries and textures. Auteurs: Norihiko Kawai;Tomokazu Sato;Yuta Nakashima;Naokazu Yokoya; Apparue dans: IEEE Transactions on Visualization and Computer Graphics Date publication: 10.-2017, volume: 23, issue:10, pages: 2288 - 2300 Editeur: IEEE Document complet vers site de l'éditeur
» Automated Classification of Breast Cancer Stroma Maturity From Histological Images
 Résumé:Objective: The tumor microenvironment plays a crucial role in regulating tumor progression by a number of different mechanisms, in particular, the remodeling of collagen fibers in tumor-associated stroma, which has been reported to be related to patient survival. The underlying motivation of this work is that remodeling of collagen fibers gives rise to observable patterns in hematoxylin and eosin (H&E) stained slides from clinical cases of invasive breast carcinoma that the pathologist can label as mature or immature stroma. The aim of this paper is to categorise and automatically classify stromal regions according to their maturity and show that this classification agrees with that of skilled observers, hence providing a repeatable and quantitative measure for prognostic studies. Methods: We use multiscale basic image features and local binary patterns, in combination with a random decision trees classifier for classification of breast cancer stroma regions-of-interest (ROI). Results: We present results from a cohort of 55 patients with analysis of 169 ROI. Our multiscale approach achieved a classification accuracy of 84%. Conclusion: This work demonstrates the ability of texture-based image analysis to differentiate breast cancer stroma maturity in clinically acquired H&E-stained slides at least as well as skilled observers. Auteurs: Sara Reis;Patrycja Gazinska;John H. Hipwell;Thomy Mertzanidou;Kalnisha Naidoo;Norman Williams;Sarah Pinder;David J. Hawkes; Apparue dans: IEEE Transactions on Biomedical Engineering Date publication: 10.-2017, volume: 64, issue:10, pages: 2344 - 2352 Editeur: IEEE Document complet vers site de l'éditeur
» Automated Detection of Ice and Open Water From Dual-Polarization RADARSAT-2 Images for Data Assimilation
 Résumé:In this paper, we present a new technique for automated detection of ice and open water from RADARSAT-2 ScanSAR dual-polarization HH-HV images. Probability of the presence of ice within 2.05 km $\times2.05$ km areas is modeled using a form of logistic regression as a function of the difference between the wind speeds estimated from synthetic aperture radar (SAR) data and those obtained from numerical weather prediction short-term forecasts, the spatial correlation between HH and HV backscatter signals, and the spatial standard deviation of the wind speed estimated from SAR. The resulting ice probability model was built based on thousands of SAR images and corresponding Canadian Ice Service (CIS) Image Analysis products covering all seasons and all Canadian and adjacent Arctic regions being monitored by CIS. Extensive verification of the proposed technique was conducted for an entire year (2013) against independent Image Analysis products and Interactive Multisensor Snow and Ice Mapping System ice extent products. Using a probability threshold of 0.95, 72.2% of the retrievals were classified as either ice or open water with an accuracy of 99.2% in the most clean verification scenario against Image Analysis pure ice and water data. The ability to obtain such a large number of retrievals with a very high accuracy makes it feasible to assimilate the resulting retrievals in an ice prediction system. Consequently, the developed ice/water retrieval technique will be implemented as a part of the data assimilation component of the operational Environment and Climate Change Canada Regional Ice-Ocean Prediction System. Auteurs: Alexander S. Komarov;Mark Buehner; Apparue dans: IEEE Transactions on Geoscience and Remote Sensing Date publication: 10.-2017, volume: 55, issue:10, pages: 5755 - 5769 Editeur: IEEE Document complet vers site de l'éditeur
» Automated Transportation of Biological Cells for Multiple Processing Steps in Cell Surgery
 Résumé:Most studies on automated cell transportation are single-task oriented. Results from these investigations hardly meet the increasing demand for emerging cell surgery operations that usually require a series of manipulation tasks with multiple processing steps. In this paper, automated cell transportation to accomplish a multistep process in cell surgery was investigated. A novel control system that can manipulate grouped cells to move into different task regions sequentially and continuously without interruption was developed based on a robot-aided optical tweezers manipulation system. A potential field-based controller was designed to achieve multistep processing control, where the new concepts of contractive coalition and switching region were incorporated into tweezers–cell coalition. The success of this controller lies in simultaneously controlling the positions of the optical tweezers, trapping multiple cells effectively, and avoiding collisions in a unified manner. Simulations and experiments of transferring a group of cells to a number of task regions were performed to demonstrate the effectiveness of the proposed approach. Note to Practitioners—This paper was motivated by the challenging problem of automated transportation of grouped cells to several predefined task regions in emerging cell surgery with multiple processing steps. Existing automated cell transportation studies are mainly single-task oriented, thereby making them inapplicable to cell surgery operations, because a series of sequential processing steps are usually involved in these operations. This paper provides a novel control strategy based on a robot-aided optical tweezers manipulation system to efficiently transport cells into different task regions sequentially without interruption. Unlike the previous cell transportation studies where the goal positions of single cells must be specified early, here only the desired task regions are i- entified in the controller implementation, making the proposed strategy a better fit for actual cell surgery practice. Auteurs: Hao Yang;Xiangpeng Li;Yunhui Liu;Dong Sun; Apparue dans: IEEE Transactions on Automation Science and Engineering Date publication: 10.-2017, volume: 14, issue:4, pages: 1712 - 1721 Editeur: IEEE Document complet vers site de l'éditeur
» Automatic and Fast PCM Generation for Occluded Object Detection in High-Resolution Remote Sensing Images
 Résumé:Partial configuration model (PCM) is an occluded object detection method in high-resolution remote sensing images (HR-RSIs) based on the deformable part-based model (DPM). However, it needs extra category predefinition, considerable part-level annotation, and repeated multimodel training. In this letter, an automatic and fast PCM generation method is proposed based on a novel part sharing mechanism. We propose to share parts from one trained DPM model (tDPM) among different models of partial configurations (PCs) to address the above problems. PCs are first designed according to part anchors of tDPM. The model is then generated through corresponding parts selection, root coverage cropping, and elements reweighing. This method avoids the need for manual category predefinition and part-level annotation, while largely reducing the computation of PCM training. Experimental results on three HR-RSI data sets show that the proposed method obtains a training speedup of $6.7\times$ and $2\times$ for each PC of airplane and ship categories, while achieving a comparable accuracy compared with PCM. Auteurs: Shaohua Qiu;Gongjian Wen;Zhipeng Deng;Yaxiang Fan;Bingwei Hui; Apparue dans: IEEE Geoscience and Remote Sensing Letters Date publication: 10.-2017, volume: 14, issue:10, pages: 1730 - 1734 Editeur: IEEE Document complet vers site de l'éditeur
» Automatic Identification of Weave Patterns of Checked and Colored Fabrics Using Optical Coherence Tomography
 Résumé:Identifying the weave pattern of fabrics can be done manually or automatically. Carrying out the weave recognition automatically will reduce the procedure time and error rates since automatic systems can perform successive measurements at high speeds and with great repeatability and quality. Woven fabric repeat identification systems that are automatic, usually work by employing complex algorithms and techniques. It is known that these automatic techniques struggle when trying to identify highly complex patterns, composing of a combination of different structures, figures, and colors. For example, image processing algorithms are known to make errors when dealing with checked and colored fabrics. In this paper, we apply the spectral domain optical coherence tomography imaging technique for identifying checked and colored woven fabric repeat automatically. This is achieved by employing an in-house written JAVA code that extracts the weave pattern from the tomography images. We show that automatic identification of weave pattern of checked and colored fabrics can be performed nondestructively by employing optical coherence tomography. Auteurs: Metin Sabuncu;Hakan Ozdemir;Mete U. Akdogan; Apparue dans: IEEE Photonics Journal Date publication: 10.-2017, volume: 9, issue:5, pages: 1 - 8 Editeur: IEEE Document complet vers site de l'éditeur
» Automatic MTPA Tracking in IPMSM Drives: Loop Dynamics, Design, and Auto-Tuning
 Résumé:Maximum Torque Per Ampere (MTPA) based on motor parameters is a common approach to achieve high efficiency and torque density in Interior Permanent Magnet Synchronous Machine Drives (IPMSMs). However, uncertainty (e.g., due to identification errors, magnetic saturation, or temperature variation) results in undesired deviation from the optimal operating trajectory. To solve this problem, MTPA tracking methods have been proposed, which exploit signal injection to search the minimum current point for a certain load torque in a closed-loop fashion. Closed-form design of the MTPA tracking loop dynamics has never been addressed in past literature and represents the main topic of this paper. A recent and efficient tracking method has been considered for the analysis and case study, i.e., [14]. Nonlinear small-signal gain of the loop can be calculated in closed form, leading to two valuable results. Dynamics can be programmed by optimal design of the tracking regulator, and online adaptation can be applied, making the designed MTPA tracking dynamics invariant with the operating point. A straightforward and effective solution is proposed for the regulator design, which allows us to obtain the desired bandwidth and first-order tracking response in the whole range of operation, being also suitable for auto-tuning and online adaptation. The method has been studied analytically and in simulation, also considering the influence of noise and parametric uncertainties. Finally the technique has been implemented on the hardware of a commercial industrial drive, proving the effectiveness of the proposal. The concepts described in this paper, design approach and adaptation strategy, analyzed here for the first time, are general and can be applied to any control scheme implementing closed-loop MTPA tracking. Auteurs: Nicola Bedetti;Sandro Calligaro;Christian Olsen;Roberto Petrella; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 4547 - 4558 Editeur: IEEE Document complet vers site de l'éditeur
» Automatic Nuclear Segmentation Using Multiscale Radial Line Scanning With Dynamic Programming
 Résumé:In the diagnosis of various cancers by analyzing histological images, automatic nuclear segmentation is an important step. However, nuclear segmentation is a difficult problem because of overlapping nuclei, inhomogeneous staining, and presence of noisy pixels and other tissue components. In this paper, we present an automatic technique for nuclear segmentation in skin histological images. The proposed technique first applies a bank of generalized Laplacian of Gaussian kernels to detect nuclear seeds. Based on the detected nuclear seeds, a multiscale radial line scanning method combined with dynamic programming is applied to extract a set of candidate nuclear boundaries. The gradient, intensity, and shape information are then integrated to determine the optimal boundary for each nucleus in the image. Nuclear overlap limitation is finally imposed based on a Dice coefficient measure such that the obtained nuclear contours do not severely intersect with each other. Experiments have been thoroughly performed on two datasets with H&E and Ki-67 stained images, which show that the proposed technique is superior to conventional schemes of nuclear segmentation. Auteurs: Hongming Xu;Cheng Lu;Richard Berendt;Naresh Jha;Mrinal Mandal; Apparue dans: IEEE Transactions on Biomedical Engineering Date publication: 10.-2017, volume: 64, issue:10, pages: 2475 - 2485 Editeur: IEEE Document complet vers site de l'éditeur
» Automatic Rich Map Semantics Identification Through Smartphone-Based Crowd-Sensing
 Résumé:Digital maps have become a part of our daily lives with a growing number of commercial and free map services. However, these services still have a huge potential for enhancement with rich semantic information to support a large class of mapping applications. In this paper, we present Map++, a system that leverages commodity off-the-shelf smartphones in a crowd-sensing approach to automatically enrich digital maps with different road semantics like tunnels, bumps, bridges, footbridges, crosswalks, road capacity, among others. Our analysis shows that the smartphones sensors, whether with a user riding a vehicle or walking, get affected by the different road features which can be mined to extend the features of both free and commercial mapping services. Map++ leverages these detected features and employs a probabilistic framework that can handle the heterogeneity and uncertainty in the crowd-sensed data to update the digital maps. We present the design and implementation of Map++ and evaluate it in four cities. Our evaluation shows that we can detect different map features accurately with 4 percent false positive and 8 percent false negative rates for in-vehicle traces, and 3 percent false positive and 4 percent false negative rates for pedestrian traces. Moreover, we show that Map++ has a small energy footprint on the cell-phones, highlighting its promise as a ubiquitous digital maps enriching service. Auteurs: Heba Aly;Anas Basalamah;Moustafa Youssef; Apparue dans: IEEE Transactions on Mobile Computing Date publication: 10.-2017, volume: 16, issue:10, pages: 2712 - 2725 Editeur: IEEE Document complet vers site de l'éditeur
» Automatically Enforcing Security SLAs in the Cloud
 Résumé:Dealing with the provisioning of cloud services granted by Security SLAs is a very challenging research topic. At the state of the art, the main related issues involve: (i) representing security features so that they are understandable by both customers and providers and measurable (by means of verifiable security-related Service Level Objectives (SLOs)), (ii) automating the provisioning of security mechanisms able to grant desired security features (by means of a security-driven resource allocation process), and (iii) continuously monitoring the services in order to verify the fulfillment of specified Security SLOs (by means of cloud security monitoring solutions). We propose to face the Security SLA life cycle management with a framework able to enrich cloud applications with security features. In this paper we (i) present a novel Security SLA model and (ii) illustrate a security-driven planning process that can be adopted to determine the (optimum) deployment of security-related software components. Such process takes into account both specific implementation constraints of the security components to be deployed and customers security requirements, and enables the automatic provisioning and configuration of all needed resources. In order to demonstrate the applicability of the approach, we present and discuss a practical application of the model on a real case study. Auteurs: Valentina Casola;Alessandra De Benedictis;Mădălina Eraşcu;Jolanda Modic;Massimiliano Rak; Apparue dans: IEEE Transactions on Services Computing Date publication: 10.-2017, volume: 10, issue:5, pages: 741 - 755 Editeur: IEEE Document complet vers site de l'éditeur
» Backstepping Design of Robust State Feedback Regulators for Linear $2 \times 2$ Hyperbolic Systems
 Résumé:This technical note deals with the robust output regulation problem for boundary controlled linear $2 \times 2$ hyperbolic systems. Thereby, the output to be controlled can be located at one of the boundaries or is a pointwise in-domain output. By utilizing the internal model principle, a state feedback regulator is determined for a finite-dimensional signal model describing the exogenous signals. This amounts to stabilizing a hyperbolic PDE-ODE cascade coupled at an intermediate point. For this, a systematic backstepping method is developed to determine the stabilizing state feedback controller. The solvability of the considered output regulation problem can easily be verified on the basis of the nominal plant transfer behaviour. For non-destabilizing model uncertainties the robustness of the achieved output regulation is verified. An uncertain hyperbolic system with an in-domain output illustrates the results of the technical note. Auteurs: Joachim Deutscher; Apparue dans: IEEE Transactions on Automatic Control Date publication: 10.-2017, volume: 62, issue:10, pages: 5240 - 5247 Editeur: IEEE Document complet vers site de l'éditeur
» Backstepping Fuzzy Adaptive Control for a Class of Quantized Nonlinear Systems
 Résumé:This paper proposes a new adaptive controller for a class of uncertain nonlinear systems with a quantized signal. Fuzzy logic systems are utilized to approximate nonlinear terms without imposing prior matching conditions required. A hysteretic type of quantizer is incorporated to reduce chattering. A new adaptive backstepping controller is designed to guarantee that the underlying uncertain nonlinear system is semiglobally uniformly ultimately bounded. Two numerical examples are presented to demonstrate the effectiveness and potential of the proposed techniques. Auteurs: Wenhui Liu;Cheng-Chew Lim;Peng Shi;Shengyuan Xu; Apparue dans: IEEE Transactions on Fuzzy Systems Date publication: 10.-2017, volume: 25, issue:5, pages: 1090 - 1101 Editeur: IEEE Document complet vers site de l'éditeur
» Bacterial Relay for Energy-Efficient Molecular Communications
 Résumé:In multi-cellular organisms, molecular signaling spans multiple distance scales and is essential to tissue structure and functionality. Molecular communications is increasingly researched and developed as a key subsystem in the Internet-of-Nano-Things paradigm. While short range microscopic diffusion communications is well understood, longer range channels can be inefficient and unreliable. Static and mobile relays have been proposed in both conventional wireless systems and molecular communication contexts. In this paper, our main contribution is to analyze the information delivery energy efficiency of bacteria mobile relays. We discover that these mobile relays offer superior energy efficiency compared with pure diffusion information transfer over long diffusion distances. This paper has widespread implications ranging from understanding biological processes to designing new efficient synthetic biology communication systems. Auteurs: Song Qiu;Werner Haselmayr;Bin Li;Chenglin Zhao;Weisi Guo; Apparue dans: IEEE Transactions on NanoBioscience Date publication: 10.-2017, volume: 16, issue:7, pages: 555 - 562 Editeur: IEEE Document complet vers site de l'éditeur
» Balanced Tri-Band Bandpass Filter Design Using Octo-Section Stepped-Impedance Ring Resonator With Open Stubs
 Résumé:A balanced tri-band bandpass filter (BPF) is proposed based on octo-section stepped-impedance ring resonator (SIRR). The relation and design graphs between the differential-mode (DM) and common-mode (CM) characteristics with different physical parameters are analyzed. It reveals that the proposed SIRR has more degrees of freedom in controlling DM and CM characteristics for tri-band design with excellent out-of-band performances and high CM suppression. Moreover, the SIRR is loaded by open stubs with different lengths to further improve the CM suppression. Finally, a balanced tri-band BPF prototype is fabricated and measured. Good agreement between simulated and experimental results verifies this design method. Auteurs: Haiwen Liu;Yi Song;Baoping Ren;Pin Wen;Xuehui Guan;Hexiu Xu; Apparue dans: IEEE Microwave and Wireless Components Letters Date publication: 10.-2017, volume: 27, issue:10, pages: 912 - 914 Editeur: IEEE Document complet vers site de l'éditeur
» Balancing of Peak Currents Between Paralleled SiC MOSFETs by Drive-Source Resistors and Coupled Power-Source Inductors
 Résumé:The peak currents between two paralleled SiC MOSFETs could differ significantly due to the mismatch in threshold voltages Vth. The method described herein employs passive compensation (drive-source resistors and coupled power-source inductors) to balance the peak currents using one gate driver, no sensors, and no feedback- without increasing total switching loss when equivalent gate-drive resistance (Rg + 0.5Rk) is kept constant. This solution works for both polarities of Vth mismatch and forces balancing from the first current peak. The extra voltage stress from this solution is mitigated by negative coupling. The passive components (resistance, self-inductance, and mutual inductance) are determined by an equation involving the magnitude of Vth mismatch, current rise time, and unbalance percentage. The influence of other parasitic inductances on current sharing is analyzed. The robustness of this passive balancing method is experimentally verified by a prototype with a significant amount of parasitic inductances. Test results show that the difference of peak currents can be reduced from 15% to 3% without changing the switching loss and voltage stress. Auteurs: Yincan Mao;Zichen Miao;Chi-Ming Wang;Khai D. T. Ngo; Apparue dans: IEEE Transactions on Industrial Electronics Date publication: 10.-2017, volume: 64, issue:10, pages: 8334 - 8343 Editeur: IEEE Document complet vers site de l'éditeur
» Bandwidth Management for Soft Real-Time Control Applications in Industrial Wireless Networks
 Résumé:Industrial distributed control systems would greatly benefit from the adoption of wireless communication technologies, if only guarantees could be provided on timing of time-critical data delivery over the ether. This paper presents solutions to handle single-hop deadline-constrained periodic traffic, which combine centralized transmission scheduling according to earliest deadline first (EDF) and automatic repeat request (ARQ). For each solution, an admission control test is provided, which guarantees a configurable number of retries to each data instance within its deadline, statically addressing both timeliness and reliability on a per-instance basis. Dynamic bandwidth management strategies are also introduced that use runtime information about unperformed guaranteed retries and reassign them, as extra retries, to failed instances whose deadline has not yet expired. Simulation results show that significant benefits can be obtained, in terms of both determinism and improved performance, by a careful static/dynamic management of the available communication resources. Auteurs: Lucia Seno;Gianluca Cena;Adriano Valenzano;Claudio Zunino; Apparue dans: IEEE Transactions on Industrial Informatics Date publication: 10.-2017, volume: 13, issue:5, pages: 2484 - 2495 Editeur: IEEE Document complet vers site de l'éditeur
» Bandwidth-efficient synchronization for fiber optic transmission: system performance measurements
 Résumé:By any measure, the various services and applications which are crucial to today's society rely on fast, efficient, and reliable information exchange. Nowadays, most of this information traffic is carried over long distances by optical fiber, which has intrinsic advantages such as wide transmission bandwidth and low attenuation. However, continuing traffic growth has imposed many challenges, especially for equipment manufacturers who have to develop optical transmission solutions to handle the demand for higher data rates without incurring increased capital and operational costs. A feasible approach to overcoming these challenges is to scale the channel capacity by employing orthogonal frequency division multiplexing (OFDM) super-channels. However, OFDM is sensitive to synchronization errors, which can result in complete failure of the receiver-based digital signal processing. Measurement results of various existing OFDM synchronization methods have highlighted inherent limitations with regards to poor system performance, which determines the quality-of-service level perceived by the end user, and complexity, which throws doubts as to their suitability for implementation in actual equipment. In this article, we provide a brief overview of optical transmission systems and some of their performance specifications. We then present a simple, robust, and bandwidth-efficient OFDM synchronization method and carry out measurements to validate the presented synchronization method with the aid of an experimental setup. Auteurs: Oluyemi Omomukuyo;Octavia A. Dobre;Ramachandran Venkatesan;Telex M. N. Ngatched; Apparue dans: IEEE Instrumentation & Measurement Magazine Date publication: 10.-2017, volume: 20, issue:5, pages: 39 - 45 Editeur: IEEE Document complet vers site de l'éditeur
» Barrier Height Variation in Ni-Based AlGaN/GaN Schottky Diodes
 Résumé:In this paper, we have investigated Ni-based AlGaN/GaN Schottky diodes comprising capping layers with silicon-technology-compatible metals such as TiN, TiW, TiWN, and combinations thereof. The observed change in Schottky barrier height of a Ni and Ni/TiW/TiWN/TiW contact can be explained by stress effects induced by the TiW/TiWN/TiW capping layer, rather than by chemical reactions at the metal–semiconductor interface. Secondary-ion mass spectroscopy and transmission electron microscopy techniques, for samples with and without a TiW/TiWN/TiW cap, have been used to show that no chemical reactions take place. In addition, electrical characterization of dedicated samples revealed that the barrier height of Ni/TiW/TiWN/TiW contacts increases after stepwise selective removal of the TiW/TiWN/TiW cap, thus demonstrating the impact of strain. Auteurs: Marcin Hajłasz;Johan J. T. M. Donkers;Saurabh Pandey;Fred Hurkx;Raymond J. E. Hueting;Dirk J. Gravesteijn; Apparue dans: IEEE Transactions on Electron Devices Date publication: 10.-2017, volume: 64, issue:10, pages: 4050 - 4056 Editeur: IEEE Document complet vers site de l'éditeur
» Bayesian Hyperspectral and Multispectral Image Fusions via Double Matrix Factorization
 Résumé:This paper focuses on fusing hyperspectral and multispectral images with an unknown arbitrary point spread function (PSF). Instead of obtaining the fused image based on the estimation of the PSF, a novel model is proposed without intervention of the PSF under Bayesian framework, in which the fused image is decomposed into double subspace-constrained matrix-factorization-based components and residuals. On the basis of the model, the fusion problem is cast as a minimum mean square error estimator of three factor matrices. Then, to approximate the posterior distribution of the unknowns efficiently, an estimation approach is developed based on variational Bayesian inference. Different from most previous works, the PSF is not required in the proposed model and is not pre-assumed to be spatially invariant. Hence, the proposed approach is not related to the estimation errors of the PSF and has potential computational benefits when extended to spatially variant imaging system. Moreover, model parameters in our approach are less dependent on the input data sets and most of them can be learned automatically without manual intervention. Exhaustive experiments on three data sets verify that our approach shows excellent performance and more robustness to the noise with acceptable computational complexity, compared with other state-of-the-art methods. Auteurs: Baihong Lin;Xiaoming Tao;Mai Xu;Linhao Dong;Jianhua Lu; Apparue dans: IEEE Transactions on Geoscience and Remote Sensing Date publication: 10.-2017, volume: 55, issue:10, pages: 5666 - 5678 Editeur: IEEE Document complet vers site de l'éditeur
» Bayesian Networks in Fault Diagnosis
 Résumé:Fault diagnosis is useful in helping technicians detect, isolate, and identify faults, and troubleshoot. Bayesian network (BN) is a probabilistic graphical model that effectively deals with various uncertainty problems. This model is increasingly utilized in fault diagnosis. This paper presents bibliographical review on use of BNs in fault diagnosis in the last decades with focus on engineering systems. This work also presents general procedure of fault diagnosis modeling with BNs; processes include BN structure modeling, BN parameter modeling, BN inference, fault identification, validation, and verification. The paper provides series of classification schemes for BNs for fault diagnosis, BNs combined with other techniques, and domain of fault diagnosis with BN. This study finally explores current gaps and challenges and several directions for future research. Auteurs: Baoping Cai;Lei Huang;Min Xie; Apparue dans: IEEE Transactions on Industrial Informatics Date publication: 10.-2017, volume: 13, issue:5, pages: 2227 - 2240 Editeur: IEEE Document complet vers site de l'éditeur
» Beam Diffraction Effects in the Backward Wave Regions of Viscoelastic Leaky Lamb Modes for Plate Transmission at Normal Incidence
 Résumé:Plane-wave theory for fluid-embedded isotropic plates is often used in ultrasonic guided-wave applications, and to estimate wall thickness, corrosion, or sound velocities in plates and pipes. In such structures, measured ultrasonic transmission through the solid material is affected by acoustic beam diffraction effects, and the results may deviate from plane-wave descriptions, which are insufficient to describe the complex effects that occur. When exciting a fluid-embedded steel plate with a pulsed ultrasonic beam at normal incidence, resonance frequency downshift, axial sound pressure level increase, and beam narrowing have been observed, for measured resonance peaks in the frequency regions of certain leaky Lamb mode branches of the plate. In the ranges of other leaky Lamb mode branches, the observed effects are different. Measurements, finite element, and angular spectrum modeling are used to indicate a close connection between these beam diffraction phenomena and the backward wave characteristics of certain leaky Lamb mode pairs, in the frequency and Poisson’s ratio regions around coincidence of two Lamb mode cutoff frequencies of similar symmetry. In particular, such observations made for the steel plate’s fundamental thickness-extensional (TE) mode appear to be caused by acoustic beam excitation of the backward wave regions of the $S_{-2}^{\mathrm{ vl}}$ and $S_{2}^{\mathrm{ vl}}$ leaky Lamb modes. Auteurs: Magne Aanes;Kjetil Daae Lohne;Per Lunde;Magne Vestrheim; Apparue dans: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control Date publication: 10.-2017, volume: 64, issue:10, pages: 1558 - 1572 Editeur: IEEE Document complet vers site de l'éditeur
» Beam Summation Theory for Waves in Fluctuating Media. Part I: The Beam Frame and the Beam-Domain Scattering Matrix
 Résumé:We present a novel beam summation (BS) formulation for tracking wavefields in fluctuating media. This formulation utilizes the ultrawideband phase-space BS method, which is structured upon a windowed Fourier transform (WFT) frame expansion of the sources and expresses the field as a discrete phase-space sum of beam propagators. This paper extends the frame concept, proving that this beam set constitutes a frame not only in the source domain, where it reduces to the conventional WFT, but everywhere in the propagation domain. This “beam frame” provides a self-consistent framework for tracking wavefields through scattering media in which the local interaction of the incident beams with the medium is expanded using the same set of beams. The resulting beam-to-beam (B2B) scattering coefficients depend on the local spectral properties of the medium. The overall B2B scattering matrix is therefore compact, coupling only beams that are adjacent in phase space, given the fluctuation properties. The new formulation expresses the entire scattering problem in terms of coefficients dynamics in the phase space. As demonstrated, the formulation is computationally efficient and captures all the relevant phenomenology. Part II extends this formulation for stochastic fields in random fluctuating medium characterized by the medium statistics. Auteurs: Matan Leibovich;Ehud Heyman; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 10.-2017, volume: 65, issue:10, pages: 5431 - 5442 Editeur: IEEE Document complet vers site de l'éditeur
» Beam–Wave Interaction From FEL to CARM and Associated Scaling Laws
 Résumé:The development of a microwave tube providing high output power (~1 MW) at a high frequency (~250 GHz) with high efficiency of the beam–wave power conversion is a challenging task. A great deal of theoretical and experimental efforts is directed toward such a goal. A promising powerful source of microwave radiation is the cyclotron autoresonance maser (CARM) oscillator. In this paper, we revisit the well-known physical models in a way, which is suitable for their implementation in the numerical tools for computer-aided design and optimization of a CARM operating at high frequency. The analysis developed by us is an attempt directed toward the realization of an adequate design tool for the development of CARM devices. Auteurs: Emanuele Di Palma;Giuseppe Dattoli;Elio Sabia;Svilen Sabchevski;Ivan Spassovsky; Apparue dans: IEEE Transactions on Electron Devices Date publication: 10.-2017, volume: 64, issue:10, pages: 4279 - 4286 Editeur: IEEE Document complet vers site de l'éditeur
» Behavior Based Human Authentication on Touch Screen Devices Using Gestures and Signatures
 Résumé:With the rich functionalities and enhanced computing capabilities available on mobile computing devices with touch screens, users not only store sensitive information (such as credit card numbers) but also use privacy sensitive applications (such as online banking) on these devices, which make them hot targets for hackers and thieves. To protect private information, such devices typically lock themselves after a few minutes of inactivity and prompt a password/PIN/pattern screen when reactivated. Passwords/ PINs/patterns based schemes are inherently vulnerable to shoulder surfing attacks and smudge attacks. In this paper, we propose BEAT, an authentication scheme for touch screen devices that authenticates users based on their behavior of performing certain actions on the touch screens. An action is either a gesture, which is a brief interaction of a user's fingers with the touch screen such as swipe rightwards, or a signature, which is the conventional unique handwritten depiction of one's name. Unlike existing authentication schemes for touch screen devices, which use what user inputs as the authentication secret, BEAT authenticates users mainly based on howthey input, using distinguishing features such as velocity, device acceleration, and stroke time. Even if attackers see what action a user performs, they cannot reproduce the behavior of the user doing those actions through shoulder surfing or smudge attacks. We implemented BEATon Samsung Focus smart phones and Samsung Slate tablets running Windows, collected 15,009 gesture samples and 10,054 signature samples, and conducted real-time experiments to evaluate its performance. Experimental results show that, with only 25 training samples, for gestures, BEATachieves an average equal error rate of 0.5 percent with three gestures and for signatures, it achieves an average equal error rate of 0.52 percent with single signature. Auteurs: Muhammad Shahzad;Alex X. Liu;Arjmand Samuel; Apparue dans: IEEE Transactions on Mobile Computing Date publication: 10.-2017, volume: 16, issue:10, pages: 2726 - 2741 Editeur: IEEE Document complet vers site de l'éditeur
» Benefiting From Kinematic Redundancy Alongside Mono- and Biarticular Parallel Compliances for Energy Efficiency in Cyclic Tasks
 Résumé:In this paper, we answer two interleaved questions. The first one is, having a redundant serial manipulator with a given cyclic task, how can we benefit simultaneously from both natural dynamics modification (NDM) and kinematic redundancy resolution to reduce the actuators’ torque? Here, the NDM is done by devising parallel nonlinear monoarticular compliances (MACs), which span one joint, and nonlinear biarticular compliances (BACs), which pass over two joints. We take advantage of kinematic redundancy to exploit the robot's natural dynamics. The second question is how do kinematic redundancy resolution and the NDM interact to minimize the cost? To answer these questions, we cast the problem of simultaneous modification and exploitation of natural dynamics into a constrained multiobjective optimization problem. We show that the set of optimal compliances has an analytical solution as a parametric function of joint trajectories. Accordingly, we study how the components of cost function affect the profile of optimal compliant elements. The proposed method is implemented on a simulated planar 3-DoF manipulator and a simulated nonplanar 4-DoF manipulator for three different tasks. The results shed light on how kinematic redundancy resolution influences efficiency of using MACs and BACs and, consequently, increases attainable gains from the NDM. Moreover, analysis of the results specifies the roles of mono- and BACs and especially explains the reason behind the particular importance of having BACs to reduce the actuation cost. Auteurs: Hamed Jalaly Bidgoly;Atoosa Parsa;Mohammad Javad Yazdanpanah;Majid Nili Ahmadabadi; Apparue dans: IEEE Transactions on Robotics Date publication: 10.-2017, volume: 33, issue:5, pages: 1088 - 1102 Editeur: IEEE Document complet vers site de l'éditeur
» Beyond Trace Ratio: Weighted Harmonic Mean of Trace Ratios for Multiclass Discriminant Analysis
 Résumé:Linear discriminant analysis (LDA) is one of the most important supervised linear dimensional reduction techniques which seeks to learn low-dimensional representation from the original high-dimensional feature space through a transformation matrix, while preserving the discriminative information via maximizing the between-class scatter matrix and minimizing the within class scatter matrix. However, the conventional LDA is formulated to maximize the arithmetic mean of trace ratios which suffers from the domination of the largest objectives and might deteriorate the recognition accuracy in practical applications with a large number of classes. In this paper, we propose a new criterion to maximize the weighted harmonic mean of trace ratios, which effectively avoid the domination problem while did not raise any difficulties in the formulation. An efficient algorithm is exploited to solve the proposed challenging problems with fast convergence, which might always find the globally optimal solution just using eigenvalue decomposition in each iteration. Finally, we conduct extensive experiments to illustrate the effectiveness and superiority of our method over both of synthetic datasets and real-life datasets for various tasks, including face recognition, human motion recognition and head pose recognition. The experimental results indicate that our algorithm consistently outperforms other compared methods on all of the datasets. Auteurs: Zhihui Li;Feiping Nie;Xiaojun Chang;Yi Yang; Apparue dans: IEEE Transactions on Knowledge and Data Engineering Date publication: 10.-2017, volume: 29, issue:10, pages: 2100 - 2110 Editeur: IEEE Document complet vers site de l'éditeur
» Biased Run-Length Coding of Bilevel Classification Label Maps of Hyperspectral Images
 Résumé:For efficient coding of bilevel sources with some dominant symbols often found in classification label maps of hyperspectral images, we proposed a novel biased run-length (BRL) coding method, which codes the most probable symbols separately from other symbols. To determine the conditions in which the BRL coding method would be effective, we conducted an analysis of the method using statistical models. We first analyzed the effect of 2-D blocking of pixels, which were assumed to have generalized Gaussian distributions. The analysis showed that the resulting symbol blocks tended to have lower entropies than the original source without symbol blocking. We then analyzed the BRL coding method applied on the sequence of block symbols characterized by a first-order Markov model. Information-theoretic analysis showed that the BRL coding method tended to generate codewords that have lower entropies than the conventional run-length coding method. Furthermore, numerical simulations on lossless compression of actual data showed improvement of the state of the art. Specifically, end-to-end implementation integrating symbol blocking, BRL, and Huffman coding achieved up to 4.3% higher compression than the JBIG2 standard method and up to 3.2% higher compression than the conventional run-length coding method on classification label maps of the widely used “Indian Pines” dataset. Auteurs: Amir Leon Liaghati;W. David Pan;Zhuocheng Jiang; Apparue dans: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing Date publication: 10.-2017, volume: 10, issue:10, pages: 4580 - 4588 Editeur: IEEE Document complet vers site de l'éditeur
» Bidirectional Polarized Reflectance Factors of Vegetation Covers: Influence on the BRF Models Results
 Résumé:In this paper, we performed multiangular measurements spanning a wide viewing range in a hemisphere space for three types of vegetation cover and analyzed the bidirectional reflectance factor (BRF) measurements based on basic physical reflectance mechanisms to ensure the accuracy of the data. The measurements and the results with the best fitted model parameters were evaluated to determine whether the BRF models produce vegetation cover reflectance factor values that are qualitatively the same as the measured values. These models effectively characterized the BRF of the vegetation cover at most of the selected wavelengths (565, 670, and 865 nm). However, for planophile vegetation cover with smooth leaves, the current BRF models did not produce accurate values in the selected visible wavelength range; the average relative difference was approximately 0.3 at 670 nm. Subsequently, we subtracted the specular reflectance factor (calculated using the bidirectional polarized reflectance factors) from the total BRF and compared these data with the modeled results. The difference between the measured and modeled BRFs was notably decreased when we separated the specular reflectance factor at 670 nm for the planophile vegetation cover with smooth leaves. Moreover, there was a different degree of improvement in the agreement between the measured and modeled results, which depended on the wavelength and the type of vegetation cover. These results indicated that the subtraction of the specular reflectance factor effectively improved the capability of the BRF models to calculate the diffuse portion of the BRF of the vegetation cover. Auteurs: Zhongqiu Sun;Di Wu;Yunfeng Lv;Yunsheng Zhao; Apparue dans: IEEE Transactions on Geoscience and Remote Sensing Date publication: 10.-2017, volume: 55, issue:10, pages: 5687 - 5701 Editeur: IEEE Document complet vers site de l'éditeur
» Big data at work: the practitioners' point of view
 Résumé:Big Data is one of the many hyper-hyped topics on which the Information Technology industry feeds itself. One can track its origins to visionary and provocative works such as the famous 2008 The End of Theory paper by Chris Anderson, in which the author argues that large enough amounts of data can effectively dilute and finally eliminate the conceptual difference between correlation and causation, favoring the former and rendering substantially useless the research of the latter [1]. More recently, less ambitious and more pragmatic approaches have been proposed, mostly elaborating on the 3-V model originally introduced by Gartner in 2012 [2]. According to this newer perspective, Big Data is about management of data involving combinations of Volumes, Velocity, and Variety that transcend the levels traditionally addressed by IT. A fourth V was later added, bringing in the additional important element of Veracity. Auteurs: Francesco Mari;Paolo Masini; Apparue dans: IEEE Instrumentation & Measurement Magazine Date publication: 10.-2017, volume: 20, issue:5, pages: 13 - 20 Editeur: IEEE Document complet vers site de l'éditeur
» Big data in I&M [Editorial]
 Résumé:Who could have imagined in the year 1950, when the first mainframes were introduced and data was stored on paper cards, that now we would each have our own personal computer with several gigabytes of memory storage? Auteurs: Wendy Van Moer; Apparue dans: IEEE Instrumentation & Measurement Magazine Date publication: 10.-2017, volume: 20, issue:5, pages: 2 - 2 Editeur: IEEE Document complet vers site de l'éditeur
» Big Data in Instrumentation and Measurement [Guest Editorial]
 Résumé:The recent rapid growth of information-gathering technologies—from health tracking sensors to smartphones and satellites—produce massive amounts of data from the real world. Similarly, a huge amount of data is steadily collected from the cyber world as a result of internet technologies. In such a context, the “Big Data” phenomenon is expected to have a dramatic impact on society. Indeed, evidence resulting from Big Data is going to support decisions that have the potential to solve big societal problems, boost billion dollar businesses or simply make our everyday lives easier. However, ensuring and understanding the quality of data is crucial to achieve these goals. On one hand, metrology— a science of information quality—is at the very heart of data science. On the other hand, data science could open a new era for measurement science. Auteurs: Dario Petri; Apparue dans: IEEE Instrumentation & Measurement Magazine Date publication: 10.-2017, volume: 20, issue:5, pages: 3 - 3 Editeur: IEEE Document complet vers site de l'éditeur
» Big data or big (privacy) problem?
 Résumé:Nowadays, almost all of us transfer data (especially personal data) to someone or something (usually through web pages), and we do not precisely know how those data are managed. All of those data, considered altogether, represent what is generally called “Big Data.” Auteurs: Veronica Scotti; Apparue dans: IEEE Instrumentation & Measurement Magazine Date publication: 10.-2017, volume: 20, issue:5, pages: 23 - 26 Editeur: IEEE Document complet vers site de l'éditeur
» Binary Frequency Shift Keying for Continuous Waveform Radar
 Résumé:A new binary frequency-shift keying (BFSK) waveform is suggested for continuous wave radar. It provides ideal periodic autocorrelation (PAC) when processed by a matched filter, and perfect periodic cross-correlation (PCC) when processed by a mismatched filter. Ideal PAC implies a uniform sidelobe level, whose ratio to the PAC peak is equal to the inverse of the code length. Perfect PCC implies zero sidelobes. BFSK is relatively spectrum efficient. Design details and processing issues are discussed. Auteurs: Nadav Levanon;Itzik Izchak Cohen; Apparue dans: IEEE Transactions on Aerospace and Electronic Systems Date publication: 10.-2017, volume: 53, issue:5, pages: 2462 - 2468 Editeur: IEEE Document complet vers site de l'éditeur
» Bioinspired Control of Walking With Toe-Off, Heel-Strike, and Disturbance Rejection for a Biped Robot
 Résumé:Human-like features, like toe-off, heel-strike, and disturbance rejection, can enhance the performance of bipedal robots. However, the required control strategies for these motions influence each other, and few studies have considered them simultaneously. Humans can walk stably with toe-off and heel-strike even after experiencing disturbances. Thus, we can study human control strategies, and then, apply them to a bipedal robot. This paper proposes a bioinspired control method to realize stable walking with toe-off and heel-strike for a bipedal robot even after disturbances. First, we analyze human walking and obtain some control strategies. Then, we propose a pattern generator and a walking controller to mimic these strategies. The pattern generator can predefine the zero-moment-point to plan the center of mass trajectory and determine appropriate foot placement. The controller adjusts torso acceleration to make the support leg compliant with the external disturbances. The controller also achieves toe-off and heel-strike in cooperation with the pattern generator. Finally, the validity of the proposed method is confirmed through simulations and experiments. Auteurs: Xuechao Chen;Zhangguo Yu;Weimin Zhang;Yu Zheng;Qiang Huang;Aiguo Ming; Apparue dans: IEEE Transactions on Industrial Electronics Date publication: 10.-2017, volume: 64, issue:10, pages: 7962 - 7971 Editeur: IEEE Document complet vers site de l'éditeur
» Birefringence Variation Independent Fiber-Optic Current Sensor Using Real-Time SOP Measurement
 Résumé:We propose a birefringence variation independent fiber-optic current sensor based on polarization diversity and a real-time state of polarization measurement technique. We theoretically and experimentally demonstrate the compensation for the degradation of Faraday effect due to the variation in birefringence of the sensing fiber. In experiment, a maximally two times higher sensitivity was achieved compared with that of the conventional one. We investigated temperature dependence of proposed method and the observed maximal variation in sensitivity is as small as 6%. The proposed method exhibits good immunity to the random variation of birefringence and the real rotation angle due to the Faraday effect can be accurately detected. Auteurs: Yinping Liu;Lin Ma;Zuyuan He; Apparue dans: IEEE Photonics Journal Date publication: 10.-2017, volume: 9, issue:5, pages: 1 - 9 Editeur: IEEE Document complet vers site de l'éditeur
» Black-Box Phase Error Compensation for Digital Phase-Shifting Profilometry
 Résumé:Due to the nonlinear response of digital phase-shifting profilometry (PSP), phase errors are inevitable in the retrieved 3-D profiles and result in negative impacts on the measurement accuracy of the PSP system. A novel method is presented in this paper to reduce the impact. Instead of compensating phase errors in the retrieved 3-D profile, specific harmonics are superimposed upon the initial fringe pattern actively to adjust the amplitudes of the harmonics in the captured fringe image with the intention to suppress the phase error, and all nonlinear response of the PSP system can be compensated in theory. Furthermore, it does not consume additional time in the 3-D profile reconstruction process. Experimental results are shown to demonstrate the validity of the method. Auteurs: Wei Zhang;Liandong Yu;Weishi Li;Haojie Xia;Huaxia Deng;Jin Zhang; Apparue dans: IEEE Transactions on Instrumentation and Measurement Date publication: 10.-2017, volume: 66, issue:10, pages: 2755 - 2761 Editeur: IEEE Document complet vers site de l'éditeur
» Blind Quality Assessment of Fused WorldView-3 Images by Using the Combinations of Pansharpening and Hypersharpening Paradigms
 Résumé:WorldView 3 (WV-3) is the first commercially deployed super-spectral, very high-resolution (HR) satellite. However, the resolution of the short-wave infrared (SWIR) bands is much lower than that of the other bands. In this letter, we describe four different approaches, which are combinations of pansharpening and hypersharpening methods, to generate HR SWIR images. Since there are no ground truth HR SWIR images, we also propose a new picture quality predictor to assess hypersharpening performance, without the need for reference images. We describe extensive experiments using actual WV-3 images that demonstrate that some approaches can yield better performance than others, as measured by the proposed blind image quality assessment model of hypersharpened SWIR images. Auteurs: Chiman Kwan;Bence Budavari;Alan C. Bovik;Giovanni Marchisio; Apparue dans: IEEE Geoscience and Remote Sensing Letters Date publication: 10.-2017, volume: 14, issue:10, pages: 1835 - 1839 Editeur: IEEE Document complet vers site de l'éditeur
» Blockchain world - Do you need a blockchain? This chart will tell you if the technology can solve your problem
 Résumé:According to a study released this July by Juniper Research, more than half the world's largest companies are now researching blockchain technologies with the goal of integrating them into their products. Projects are already under way that will disrupt the management of health care records, property titles, supply chains, and even our online identities. But before we remount the entire digital ecosystem on blockchain technology, it would be wise to take stock of what makes the approach unique and what costs are associated with it. Blockchain technology is, in essence, a novel way to manage data. As such, it competes with the data-management systems we already have. Relational databases, which orient information in updatable tables of columns and rows, are the technical foundation of many services we use today. Decades of market exposure and well-funded research by companies like Oracle Corp. have expanded the functionality and hardened the security of relational databases. However, they suffer from one major constraint: They put the task of storing and updating entries in the hands of one or a few entities, whom you have to trust won't mess with the data or get hacked. Auteurs: Morgen E. Peck; Apparue dans: IEEE Spectrum Date publication: 10.-2017, volume: 54, issue:10, pages: 38 - 60 Editeur: IEEE Document complet vers site de l'éditeur
» Blockchain world - Feeding the blockchain beast if bitcoin ever does go mainstream, the electricity needed to sustain it will be enormous
 Résumé:Bitcoin "miners" are electromagnetic alchemists, effectively turning megawatt-hours of electricity into the world's fastest-growing currency. Their intensive computational activity cryptographically secures the virtual currency, approves transactions, and, in the process, creates new bitcoins for the miners, as payment. And it does another thing, too: It uses an absolutely stunning amount of power. The ever-expanding racks of processors used by miners already consume as much electricity as a small city. It's a problem that experts say is bad and getting worse. "The concern that people continue to debate is, where does this end?" says Michael Reed, head of blockchain technology for Intel. The Bitcoin leech sucking on the world's power grids has been held in check, so far, by rapid gains in the energy efficiency of mining hardware. But energy and blockchain analysts are worried about the possibility of a perfect storm: Those efficiency gains are slowing while bitcoin value is rising fast-and its potential transaction growth is immense. Auteurs: Peter Fairley; Apparue dans: IEEE Spectrum Date publication: 10.-2017, volume: 54, issue:10, pages: 36 - 59 Editeur: IEEE Document complet vers site de l'éditeur
» Blockchains: How they work and why they'll change the world
 Résumé:Bitcoin was hatched as an act of defiance. Unleashed in the wake of the Great Recession, the cryptocurrency was touted by its early champions as an antidote to the inequities and corruption of the traditional financial system. They cherished the belief that as this parallel currency took off, it would compete with and ultimately dismantle the institutions that had brought about the crisis. Bitcoin's unofficial catchphrase, "In cryptography we trust," left no doubt about who was to blame: It was the middlemen, the bankers, the "trusted" third parties who actually couldn't be trusted. These humans simply got in the way of other humans, skimming profits and complicating transactions. Auteurs: Morgen E. Peck; Apparue dans: IEEE Spectrum Date publication: 10.-2017, volume: 54, issue:10, pages: 26 - 35 Editeur: IEEE Document complet vers site de l'éditeur
» Book Reviews [7 Reviews]
 Résumé:The following books are reviewed: Computational Intelligence Applications in Smart Grids by A.F. Zobaa and A. Vaccaro; Tailoring of Nanocomposite Dielectrics by T. Tanaka and A.S. Vaughan; Smart Microgrids-Lessons from Campus Microgrid Design and Implementation by H. Farhangi; Principles and Applications of Ubiquitous Sensing by W. Dargie; Understanding Symmetrical Components for Power System Modeling by J.C. Das; Internet of Things and Data Analytics Handbook by H. Geng; Physics of Digital Photography by A. Rowlands Auteurs: John J. Shea; Apparue dans: IEEE Electrical Insulation Magazine Date publication: 10.-2017, volume: 33, issue:5, pages: 56 - 59 Editeur: IEEE Document complet vers site de l'éditeur
» Boosting the Accuracy of Multispectral Image Pansharpening by Learning a Deep Residual Network
 Résumé:In the field of multispectral (MS) and panchromatic image fusion (pansharpening), the impressive effectiveness of deep neural networks has recently been employed to overcome the drawbacks of the traditional linear models and boost the fusion accuracy. However, the existing methods are mainly based on simple and flat networks with relatively shallow architectures, which severely limits their performance. In this letter, the concept of residual learning is introduced to form a very deep convolutional neural network to make the full use of the high nonlinearity of the deep learning models. Through both quantitative and visual assessments on a large number of high-quality MS images from various sources, it is confirmed that the proposed model is superior to all the mainstream algorithms included in the comparison, and achieves the highest spatial–spectral unified accuracy. Auteurs: Yancong Wei;Qiangqiang Yuan;Huanfeng Shen;Liangpei Zhang; Apparue dans: IEEE Geoscience and Remote Sensing Letters Date publication: 10.-2017, volume: 14, issue:10, pages: 1795 - 1799 Editeur: IEEE Document complet vers site de l'éditeur
» BRAIN: A Low-Power Deep Search Engine for Autonomous Robots
 Résumé:Autonomous robots are actively studied for many unmanned applications, however, the heavy computational costs and limited battery capacity make it difficult to implement intelligent decision making in robots. In this article, the authors propose a low-power deep search engine (code-named “BRAIN”) for real-time path planning of intelligent autonomous robots. To achieve low power consumption while maintaining high performance, BRAIN adopts a multithreaded core architecture with a transposition table cache to detect and avoid duplicated searches between the processors at the deeper level of the search tree. In addition, dynamic voltage and frequency scaling is adopted to minimize power consumption without any loss of performance because the workload is gradually decreasing while approaching the target position. BRAIN achieves fast search speed (470,000 searches per second) and low energy consumption (79 nJ per search), and it is successfully applied to the robots for autonomous navigation without any collision in dynamic environments. Auteurs: Youchang Kim;Dongjoo Shin;Jinsu Lee;Hoi-Jun Yoo; Apparue dans: IEEE Micro Date publication: 10.-2017, volume: 37, issue:5, pages: 11 - 19 Editeur: IEEE Document complet vers site de l'éditeur
» Bridging the Gap Between OpenMP and Task-Based Runtime Systems for the Fast Multipole Method
 Résumé:With the advent of complex modern architectures, the low-level paradigms long considered sufficient to build High Performance Computing (HPC) numerical codes have met their limits. Achieving efficiency, ensuring portability, while preserving programming tractability on such hardware prompted the HPC community to design new, higher level paradigms while relying on runtime systems to maintain performance. However, the common weakness of these projects is to deeply tie applications to specific expert-only runtime system APIs. The OpenMP specification, which aims at providing common parallel programming means for shared-memory platforms, appears as a good candidate to address this issue thanks to the latest task-based constructs introduced in its revision 4.0. The goal of this paper is to assess the effectiveness and limits of this support for designing a high-performance numerical library, ScalFMM, implementing the fast multipole method (FMM) that we have deeply re-designed with respect to the most advanced features provided by OpenMP 4. We show that OpenMP 4 allows for significant performance improvements over previous OpenMP revisions on recent multicore processors and that extensions to the 4.0 standard allow for strongly improving the performance, bridging the gap with the very high performance that was so far reserved to expert-only runtime system APIs. Auteurs: Emmanuel Agullo;Olivier Aumage;Berenger Bramas;Olivier Coulaud;Samuel Pitoiset; Apparue dans: IEEE Transactions on Parallel and Distributed Systems Date publication: 10.-2017, volume: 28, issue:10, pages: 2794 - 2807 Editeur: IEEE Document complet vers site de l'éditeur
» Bridging the Gap Between Ultrapure Water and Reference Materials in Electrolytic Conductivity Measurements
 Résumé:This paper reports a closed-flow-loop electrolytic conductivity measurement system enabling calibration of conductivity sensors from the conductivity level of ultrapure water (UPW) at $5.5~\mu \text{S}$ /m up till the range of 10 to 140 mS/m, where stable certified reference materials (CRMs) for conductivity are available. The system is traceable to the SI unit system. A comparison made with another electrolytic conductivity measurement system, which is based on Jones-type conductivity cells designed to be used primarily for conductivities larger than ~10 mS/m, shows an agreement better than 0.1%. The most commonly used calibration method of conductivity sensors is based on CRMs and the extrapolation of the data to low conductivity values ( $< 1000~\mu \text{S}$ /m). In contrast, the present closed-flow-loop electrolytic conductivity measurement system is based on the measurements made at conductivity levels where the sensor is used; it is, therefore, a better alternative. Auteurs: Carsten Thirstrup;Alan Snedden;Hans D. Jensen; Apparue dans: IEEE Transactions on Instrumentation and Measurement Date publication: 10.-2017, volume: 66, issue:10, pages: 2745 - 2754 Editeur: IEEE Document complet vers site de l'éditeur
» Brillouin Backscattering Light Properties of Chaotic Laser Injecting Into an Optical Fiber
 Résumé:Laser diode-based optical chaos is attractive for the fundamental physics as well as practical tasks in such as secure communications, random number generation, and fiber sensing. The characteristics of Brillouin backscattering light generated by injecting a chaotic laser into a single mode fiber have been investigated experimentally. The Brillouin backscattering light still has the chaotic properties, and the position of the chaotic anti-Stokes frequency appears a dip, which has never been reported before. The power and linewidth variations of the Brillouin Stokes light and anti-Stokes light along with the input optical power also are analyzed. Particularly, we investigate the differences of Brillouin backscattering light between chaotic laser and narrow-linewidth laser, and analyze the interacted optical spectra when the chaotic laser and the narrow-linewidth laser inject into the 10 km single mode fiber simultaneously. With detailed analysis and experimental validation, we demonstrate that due to the chaotic self-similarity property, the chaotic laser at the location of anti-Stokes frequency transforms into the Stokes light in the stimulated Brillouin scattering process, which leads to the appearing of the dip. Auteurs: Mingjiang Zhang;Hui Liu;Jianzhong Zhang;Yi Liu;Ruixia Liu; Apparue dans: IEEE Photonics Journal Date publication: 10.-2017, volume: 9, issue:5, pages: 1 - 10 Editeur: IEEE Document complet vers site de l'éditeur
» Broadband Decoupling Network for Dual-Band Microstrip Patch Antennas
 Résumé:Microstrip antenna (MSA) has become one of the most popular techniques in the modern communication systems because of its potentials in diversities of operating band and polarization. With the development of highly compact circuits, the isolation between each terminal of a multi-input-multi-output (MIMO) system becomes more and more important to reach high system accuracy. Here, we propose an innovative approach of decoupling for a dual-band MSA, in which the isolation is achieved through two kinds of transmission lines based on the substrate integrated waveguide (SIW) and miniaturized spoof surface plasmon polariton (SSPP). Both SIW and SSPP transmission lines have been used in functional devices and could be considered as part of radio frequency front-end circuits. Using the proposed method, the isolation between two ports of MSA is achieved without occupying extra space. A prototype is fabricated on the basis of a triple-layer dual-band MSA, each port of which is connected to one of the novel transmission lines. Combining the perfectly high-pass SIW and low-pass SSPP, the proposed feeding network could provide broadband decoupling without influencing the property of the antenna. We show that the mutual coupling between two ports is decreased by almost 20 dB within a wide frequency band. Such a design could meet the needs in application of multiantenna or tunable system without further alteration in dimensions and has potential to play an important role in the future communication systems. Auteurs: Bai Cao Pan;Tie Jun Cui; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 10.-2017, volume: 65, issue:10, pages: 5595 - 5598 Editeur: IEEE Document complet vers site de l'éditeur
» Broadband Measurement Methodology for Specific Absorption Rates Above 300 MHz
 Résumé:Specific absorption rate (SAR) is an indicator of biological effects on human tissue caused by exposure to microwave radiation. An electric field probe scanning method has been traditionally used for SAR evaluation. However, since the electric field probe exhibits strong frequency dependence, it is difficult to evaluate SAR continuously in the broadband. In addition, preparing a physically different SAR measurement methodology from the electric field probe is an important task for validating measurement standards or regulations. Therefore, the authors developed a thermal SAR measurement method using optical fiber thermal sensors. In the present paper, we present a thermal SAR evaluation methodology that can be used in the broadband from 300 MHz to 6 GHz, which is frequently used by mobile devices. It was confirmed for the first time that SAR showed the peak with this continuous broadband measurement around 1.8 GHz. In addition, as a comparison measurement result with the electric field probe system and the proposed system, the mean value of each measured datum showed a deflection of approximately 10% to 20% in the whole frequency range. Auteurs: Yoshinobu Okano;Ryo Shimofusa;Mitsuki Anbai;Kaoru Someno; Apparue dans: IEEE Transactions on Instrumentation and Measurement Date publication: 10.-2017, volume: 66, issue:10, pages: 2693 - 2702 Editeur: IEEE Document complet vers site de l'éditeur
 Résumé:Herein, we present a spectrally tunable add/drop filter based on a dielectric double-disk microcavity. Numerical simulation shows that a whispering gallery mode of this filter has a very large wavelength tuning range of 103 nm for a 20 nm change of an air slot between the double disks. Based on this mechanism, broadband wavelength tuning and on/off switching are demonstrated in this paper. Under the resonance condition, drop power and through power at gap size of 10 nm were obtained as 0.87 and 0.0036, while the on/off ratios of the signal at the through port and the drop port were 35:1 and 105:1, respectively. Auteurs: Young Jin Lee;Da Eun Lee;Soon-Hong Kwon; Apparue dans: IEEE Photonics Journal Date publication: 10.-2017, volume: 9, issue:5, pages: 1 - 7 Editeur: IEEE Document complet vers site de l'éditeur
» Broadbeam Cross-Dipole Antenna for GPS Applications
 Résumé:A broadbeam cross-dipole antenna with improved low-elevation gain for global positioning system (GPS) applications is reported. The cross-dipole consists of two perpendicular dipoles, which are printed on two separate substrates that are vertically placed inside a cylindrical back cavity. Circularly polarized fields are generated by applying two quadrature signals with equal amplitude to the dipoles. To enhance the low-elevation gain, circular dipoles, curved ground planes, and corrugated back cavity are deployed in our design. A prototype operating in GPS L1 band (1.575 GHz) was designed with ANSYS HFSS, and measurement was done to verify the simulations. The reflection coefficient, axial ratio (AR), radiation pattern, antenna gain, and antenna efficiency are studied. It is found that the antenna has a wide 3 dB AR beamwidth of over 230° and a 3 dB gain beamwidth of 150°. The measured and simulated antenna gains at $\theta = 85^{\circ }$ are 0.11 and 0.68 dBic, respectively, which are higher than those of existing designs. Auteurs: Yu-Xiang Sun;Kwok Wa Leung;Kai Lu; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 10.-2017, volume: 65, issue:10, pages: 5605 - 5610 Editeur: IEEE Document complet vers site de l'éditeur
» Buried and Surface Mine Detection From Thermal Image Time Series
 Résumé:Millions of buried and surface landmines throughout the world will continue to kill and injure people for many decades. Reliable landmine detection systems, especially those that do not require that an operator enters a minefield, are demanded. In such systems, data are captured by sensors and processed with signal-processing techniques. In recent studies, ground-penetrating radars, ultrasound transducers, metal detectors, and infrared sensors have been used to capture data as individual images or image time series. Bare soil and mines have different thermal characteristics, and this difference can be observed on the soil surface with thermal sensors. Since this is a dynamic behavior driven by radiation from the sun and changes with temperature during the day, it can be observed better in thermal image time series. In the proposed method, a two-step approach is adopted: pixelwise classification followed by mine detection. In the first step, a specific spatial filter is applied on images and the filtered image series is classified pixelwise using supervised classification. In the second step, the classified pixels are combined after a smoothing operation to detect mines. The types of the detected mines can also be determined. The method is tested on real data to quantify its classification and detection performance. The results are quite promising. Among the classifiers tested in this paper, the quadratic discriminate function classifier produces the best results. Auteurs: Serkan Kaya;Ugur Murat Leloglu; Apparue dans: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing Date publication: 10.-2017, volume: 10, issue:10, pages: 4544 - 4552 Editeur: IEEE Document complet vers site de l'éditeur
» Caching Placement with Recommendation Systems for Cache-Enabled Mobile Social Networks
 Résumé:Caching popular contents at user devices and sharing the cached content among users is one promising solution to alleviate the heavy base station burden in mobile social networks. In this letter, we investigate social relationships and physical coupling among users, and, then, choose one important user (IU) as a helper to cache target contents and other users can get contents from IUs devices. In particular, because users tend to pay more attention to contents they interested in, a recommendation system with caching placement is proposed to maximize the offloading probability for mobile social networks. We then improve the system to combine three operations: pre-filtering, collaborative filtering algorithm, and latent factor algorithm. Finally, simulation results show the proposed recommendation system-based caching placement scheme achieves a great performance gain over existing approaches, and indicate that important user devices should cache files that recommended most to users. Auteurs: Yanfeng Wang;Mingyang Ding;Zhiyong Chen;Ling Luo; Apparue dans: IEEE Communications Letters Date publication: 10.-2017, volume: 21, issue:10, pages: 2266 - 2269 Editeur: IEEE Document complet vers site de l'éditeur
» Calculating the Phase Center of an Antenna: A Simple Experimental Method Based on Linear Near-Field Measurements. [Measurements Corner]
 Résumé:In this article, a simple experimental method based on linear near-field (NF) measurements for finding the real position of the phase center of an antenna is presented. To do that, measurements along both principal axes of the antenna are carried out. Then, each set of data is treated individually to determine the phase center for each principal plane. In this method, the measured phase is expressed in terms of the relative position to the axis as a quadratic expression, in which the independent term gives the perpendicular distance from the points of the measurement to the estimated phase center. Thus, this value is obtained by adjusting a second-order polynomial expression to the curve of the measured phase. The operational limits of the method are generally determined by the amplitude variation of the measured field. To establish these limits and verify their functionality, a series of simulations is carried out. Finally, the method is used to characterize some real antennas. Auteurs: Enrique G. Plaza;German Leon;Susana Loredo;Luis F. Herran; Apparue dans: IEEE Antennas and Propagation Magazine Date publication: 10.-2017, volume: 59, issue:5, pages: 130 - 175 Editeur: IEEE Document complet vers site de l'éditeur
» Calculation of Touch Voltage Based on Physical Distribution of Earth Fault Current
 Résumé:In this paper, the finite-elements method was used to analyze the approximation being typically used in the international standards for the calculation of the touch voltage, appearing at earth faults in power networks. The calculations in this paper were performed on the series of earthing systems applied in practice and the results are compared with the results of the widely accepted approximate method from standards. The origin of discrepancy in the results is analyzed and evaluated. The outcome of this paper is the justification of the application of Thevenin's theorem and the development of the higher accuracy equations for the resistance between feet and remote earth in case of the application of high resistivity additional surface material. Auteurs: Stevan Stanisic;Zoran Radakovic; Apparue dans: IEEE Transactions on Power Delivery Date publication: 10.-2017, volume: 32, issue:5, pages: 2246 - 2254 Editeur: IEEE Document complet vers site de l'éditeur
» Calibration With a Monocone on a Ground Plane
 Résumé:Calibration with a monocone on a ground plane (CALMOPLA) is a tool for the calibration of low-sensitivity and ultrawideband (UWB) electric or magnetic field probes. It consists of a small conical monopole (D-dot), positioned in the center of a ground plane and emitting electromagnetic waves. Close to the reference plane, the radiated signals are quasi-spherical waves which can be described by well-known analytical expressions. The originality of the CALMOPLA calibration method consists in radiating at once spherical waves at UWB frequencies (from several tens of megahertz to several gigahertz) with a unique emitter, in free-field (377- $\Omega$ impedance), in delivering a signal amplitude usable for low-sensitivity sensor calibration, and this with reasonable geometrical dimensions. A vector network analyzer is sufficient to cover the frequency range of most of the sensors to be calibrated. Nevertheless, the use of a low-noise amplifier and a low-frequency power amplifier allows the measurement range to be extended to a very low-sensitivity sensor anywhere on CALMOPLA. Auteurs: Francois Bieth;Philippe Delmote; Apparue dans: IEEE Transactions on Plasma Science Date publication: 10.-2017, volume: 45, issue:10, pages: 2744 - 2747 Editeur: IEEE Document complet vers site de l'éditeur
» CAN With eXtensible In-Frame Reply: Protocol Definition and Prototype Implementation
 Résumé:Controller area network (CAN) has been the de facto standard in the automotive industry for the past two decades. Recently, CAN with flexible data-rate (CAN FD) has been standardized, which achieves noticeably higher throughput. Further improvements are still possible for CAN, by exploiting its peculiar physical layer to carry out distributed operations among network nodes, implemented as atomic transactions mapped on quasi-conventional frame exchanges. In this paper, a proposal is made for an extension to the CAN protocol, termed CAN with eXtensible in-frame Reply (CAN XR), which enables upper protocol layers to define new custom services devoted to, e.g., network management, application-specific functions, and high-efficiency data transfer. The key point is that CAN XR retains full backward compatibility with CAN, therefore, there is no need to change the protocol specification once again. Auteurs: Gianluca Cena;Ivan Cibrario Bertolotti;Tingting Hu;Adriano Valenzano; Apparue dans: IEEE Transactions on Industrial Informatics Date publication: 10.-2017, volume: 13, issue:5, pages: 2436 - 2446 Editeur: IEEE Document complet vers site de l'éditeur
» Cancer Subtype Discovery Based on Integrative Model of Multigenomic Data
 Résumé:One major goal of large-scale cancer omics study is to understand molecular mechanisms of cancer and find new biomedical targets. To deal with the high-dimensional multidimensional cancer omics data (DNA methylation, mRNA expression, etc.), which can be used to discover new insight on identifying cancer subtypes, clustering methods are usually used to find an effective low-dimensional subspace of the original data and then cluster cancer samples in the reduced subspace. However, due to data-type diversity and big data volume, few methods can integrate these data and map them into an effective low-dimensional subspace. In this paper, we develop a dimension-reduction and data-integration method for indentifying cancer subtypes, named Scluster. First, Scluster, respectively, projects the different original data into the principal subspaces by an adaptive sparse reduced-rank regression method. Then, a fused patient-by-patient network is obtained for these subgroups through a scaled exponential similarity kernel method. Finally, candidate cancer subtypes are identified using spectral clustering method. We demonstrate the efficiency of our Scluster method using three cancers by jointly analyzing mRNA expression, miRNA expression, and DNA methylation data. The evaluation results and analyses show that Scluster is effective for predicting survival and identifies novel cancer subtypes of large-scale multi-omics data. Auteurs: Shu-Guang Ge;Junfeng Xia;Wen Sha;Chun-Hou Zheng; Apparue dans: IEEE/ACM Transactions on Computational Biology and Bioinformatics Date publication: 10.-2017, volume: 14, issue:5, pages: 1115 - 1121 Editeur: IEEE Document complet vers site de l'éditeur
» Capacity and Expressiveness of Genomic Tandem Duplication
 Résumé:The majority of the human genome consists of repeated sequences. An important type of repeated sequences common in the human genome are tandem repeats, where identical copies appear next to each other. For example, in the sequence $AGTC\underline {TGTG}C$ , $TGTG$ is a tandem repeat, that may be generated from $AGTCTGC$ by a tandem duplication of length 2. In this paper, we investigate the possibility of generating a large number of sequences from a seed, i.e. a small initial string, by tandem duplications of bounded length. We study the capacity of such a system, a notion that quantifies the system’s generating power. Our results include exact capacity values for certain tandem duplication string systems. In addition, motivated by the role of DNA sequences in expressing proteins via RNA and the genetic code, we define the notion of the expressiveness of a tandem duplication system as the capability of expressing arbitrary substrings. We then completely characterize the expressiveness of tandem duplication systems for general alphabet sizes and duplication lengths. In particular, based on a celebrated result by Axel Thue from 1906, presenting a construction for ternary squarefree sequences, we show that for alphabets of size 4 or larger, bounded tandem duplication systems, regardless of the seed and the bound on duplication length, are not fully expressive, i.e. they cannot generate all strings even as substrings of other strings. Note that the alphabet of size 4 is of particular interest as it pertains to the genomic alphabet. Building on this result, we also show that these systems do not have full capacity. In general, our results illustrate that duplication len- ths play a more significant role than the seed in generating a large number of sequences for these systems. Auteurs: Siddharth Jain;Farzad Farnoud Hassanzadeh;Jehoshua Bruck; Apparue dans: IEEE Transactions on Information Theory Date publication: 10.-2017, volume: 63, issue:10, pages: 6129 - 6138 Editeur: IEEE Document complet vers site de l'éditeur
» Capacity Bounds for the $K$ -User Gaussian Interference Channel
 Résumé:The capacity region of the $K$ -user Gaussian interference channel (GIC) is a long-standing open problem and even capacity outer bounds are little known in general. A significant progress on degrees-of-freedom (DoF) analysis, a first-order capacity approximation, for the $K$ -user GIC has provided new important insights into the problem of interest in the high signal-to-noise ratio (SNR) limit. However, such capacity approximation has been observed to have some limitations in predicting the capacity at finite SNR. In this paper, we develop a new upper-bounding technique that utilizes a new type of genie signal and applies time sharing to genie signals at $K$ receivers. Based on this technique, we derive new upper bounds on the sum capacity of the three-user GIC with constant, complex channel coefficients and then generalize to the $K$ -user case to better understand sum-rate behavior at finite SNR. We also provide closed-form expressions of our upper bounds on the capacity of the $K$ -user symmetric GIC easily computable for any $K$ . From the perspectives of our results, some sum-rate behavior at finite SNR is in line with the insights given by the known DoF results, while some others are not. In particular, the well-known $K/2$ DoF achievable for almost all constant real channel coefficients turns out to be not embodied as a substantial performance gain over a certain range of the cross-channel coefficient in the $K$ -user symmetric real case especially for large $K$ . We further investigate the impact of phase offset between the direct-channel coefficient and the cross-channel coefficients on the sum-rate upper bound for the three-user complex GIC. As a consequence, we aim to provide new findings that could not be predicted by the prior works on DoF of GICs. Auteurs: Junyoung Nam; Apparue dans: IEEE Transactions on Information Theory Date publication: 10.-2017, volume: 63, issue:10, pages: 6416 - 6439 Editeur: IEEE Document complet vers site de l'éditeur
» Capacity Comparison Between MIMO-NOMA and MIMO-OMA With Multiple Users in a Cluster
 Résumé:In this paper, the performance of multiple-input multiple-output non-orthogonal multiple access (MIMO-NOMA) is investigated, when multiple users are grouped into a cluster. The superiority of MIMO-NOMA over MIMO-OMA in terms of both sum channel capacity and ergodic sum capacity is proved analytically. Furthermore, it is demonstrated that the more users are admitted to a cluster, the lower is the achieved sum rate, which illustrates the tradeoff between the sum rate and maximum number of admitted users. On this basis, a user admission scheme is proposed, which is optimal in terms of both sum rate and the number of admitted users when the signal-to-interference-plus-noise ratio thresholds of the users are equal. When these thresholds are different, the proposed scheme still achieves good performance in balancing both criteria. Moreover, under certain conditions, it maximizes the number of admitted users. In addition, the complexity of the proposed scheme is linear in the number of users per cluster. Simulation results verify the superiority of MIMO-NOMA over MIMO-OMA in terms of both sum rate and user fairness, as well as the effectiveness of the proposed user admission scheme. Auteurs: Ming Zeng;Animesh Yadav;Octavia A. Dobre;Georgios I. Tsiropoulos;H. Vincent Poor; Apparue dans: IEEE Journal on Selected Areas in Communications Date publication: 10.-2017, volume: 35, issue:10, pages: 2413 - 2424 Editeur: IEEE Document complet vers site de l'éditeur
» Capacity Statistics Evaluation for Next Generation Broadband MEO Satellite Systems
 Résumé:In this paper, the performance of a reference medium earth orbit (MEO) satellite constellation system operating at Ka-band and employing single links to ground is compared with next generation advanced systems in higher RF or optical bands employing multiple diversity links. The fill rate of existing MEO constellations offering broadband and trunking services in Ka-band is growing fast, rendering the search for additional spectrum of vital importance. Therefore, this paper reports on the results of a system study investigating the option of using Q/V-band, or even optical wavelengths, instead of Ka-band, to deliver substantially higher system capacity. The system study takes a holistic approach covering from atmospheric channel impairments to waveform optimization and system analysis for realistic assumptions. After proposing a sophisticated channel model to generate spatio-temporal time series of atmospheric attenuation, an optimization of the performance at physical layer is performed to derive the inputs necessary to the system analysis. Five different advanced high frequency RF and optical systems are compared in terms of outage capacity and availability for various locations of single ground stations, multiple ground stations (site diversity) and from multiple satellites (orbital diversity). For maximizing the realism of the comparison, similar on board satellite resources (mass, power) are assumed for all scenarios. Auteurs: Charilaos I. Kourogiorgas;Nikolaos Lyras;Athanasios D. Panagopoulos;Daniele Tarchi;Alessandro Vanelli-Coralli;Alessandro Ugolini;Giulio Colavolpe;Pantelis-Daniel Arapoglou; Apparue dans: IEEE Transactions on Aerospace and Electronic Systems Date publication: 10.-2017, volume: 53, issue:5, pages: 2344 - 2358 Editeur: IEEE Document complet vers site de l'éditeur
» Capless LDO Regulator Achieving −76 dB PSR and 96.3 fs FOM
 Résumé:The performance of switching devices such as display driver ICs is degraded by large power supply noise at switching frequencies from a few hundreds of kilohertz to a few megahertz. In order to minimize the power supply noise, a low-dropout (LDO) regulator with higher power supply rejection (PSR) is essential. In this brief, a capless LDO regulator with a negative capacitance circuit and voltage damper is proposed for enhancing PSR and figure of merit (FOM), respectively, in switching devices. The proposed LDO regulator is fabricated in a $0.18~\boldsymbol {\mu }\text{m}$ CMOS. Measurement results show that the proposed LDO regulator achieves −76 dB PSR at 1 MHz and 96.3 fs FOM with a total on-chip capacitance of as small as 12.7 pF. Auteurs: Seong Jin Yun;Jeong Seok Yun;Yong Sin Kim; Apparue dans: IEEE Transactions on Circuits and Systems II: Express Briefs Date publication: 10.-2017, volume: 64, issue:10, pages: 1147 - 1151 Editeur: IEEE Document complet vers site de l'éditeur
» Carbon Nanotube Nanocomposite Having Segregated Network Structure for Wearable Thermotherapy Application
 Résumé:Multiwalled nanotube (MWNT)/silicone composites having segregated MWNT network and micro-void structure were developed for wearable thermotherapy application. The nano-composites could be quickly fabricated from instant evaporation of aqueous medium during spray coating process. Fast electric heating behavior (4.8 °C/s) was demonstrated, in comparison with that (1.4 °C/s) of conventional silicone rubber composites having no void. Long-term stability was also verified with thermal aging and thermal cycling tests up to 100 h. Auteurs: Dongouk Kim;Sang-Eui Lee;Kunmo Chu;Sung-Hoon Park;Yoonchul Sohn; Apparue dans: IEEE Electron Device Letters Date publication: 10.-2017, volume: 38, issue:10, pages: 1489 - 1491 Editeur: IEEE Document complet vers site de l'éditeur
» Career Management: Ten Important Things to Keep in Mind
 Résumé:Your career can serve as an expression of who you are, what values you have, and what you seek to accomplish. Certainly compensation is a consideration. However, in my over 30 years as an engineer, manager, and executive in the electric utility industry, the most fulfilled, engaging, and passionate individuals I have met, regardless of "rank," have been those whose work was most closely aligned with their personal interests and beliefs. Auteurs: Christopher E. Root; Apparue dans: IEEE Potentials Date publication: 10.-2017, volume: 36, issue:5, pages: 13 - 16 Editeur: IEEE Document complet vers site de l'éditeur
» Carrier Recovery Schemes for Submillimeter Wave Wireless Transmission
 Résumé:By moving carrier frequencies to higher and higher frequency bands, larger bandwidths can be provided for data-hungry wireless applications. The submillimeter wave region is a promising candidate for future systems. In order to accommodate sophisticated modulation formats, coherent local oscillators in the transmitter (TX) and the receiver (RX) are needed for efficient operation. However, traditional methods of analog carrier recovery (e.g., narrowband filtering of the residual carrier and reamplification) fail at such high frequencies and for many modulation formats. Also, digital carrier recovery algorithms used in conjunction with free-running oscillators are too power hungry and hard to realize for high data rates above 10 Gb/s. In this paper, carrier recovery schemes based on the parallel transmission of a reference frequency together with the payload data suitable for high data rates in the submillimeter waveband are proposed. They are demonstrated at 300-GHz carrier frequency. The corresponding electronic circuits for the TX and the RX are designed, manufactured, and characterized. Auteurs: Niels Neumann;Martin Laabs;Torge B. Keuter;Dirk Plettemeier; Apparue dans: IEEE Transactions on Microwave Theory and Techniques Date publication: 10.-2017, volume: 65, issue:10, pages: 3633 - 3639 Editeur: IEEE Document complet vers site de l'éditeur
» Case Study of a Hybrid Optoelectronic Limiting Receiver
 Résumé:The systematic design analysis of a hybrid optoelectronic limiting receiver is presented. The limiting receiver was designed in the IBM 130-nm CMOS process and side-by-side wire bonded to a commercial high-speed InGaAs/InP PIN photodiode. The CMOS die and the optical die were chip-on-board (COB) mounted on the Printed Circuit Board. Partition between small signal in the linear region and large-signal in the limiting region is emphasized. The signal edges can get sharpened in the limiting region although the front-end circuit is bandwidth-limited. When tested with a PRBS-31 pattern, the prototype achieved a bit-error rate of $10^{-12}$ at the sensitivity level of −3.2-dBm Mach-Zehnder Modulator optical modulation amplitude at 4 Gb/s. Conclusions derived from this paper can provide insights to guide other optical limiting receiver design and testing at higher speeds. Auteurs: Kehan Zhu;Vishal Saxena; Apparue dans: IEEE Transactions on Circuits and Systems I: Regular Papers Date publication: 10.-2017, volume: 64, issue:10, pages: 2797 - 2805 Editeur: IEEE Document complet vers site de l'éditeur
» Case-Based Regression Models Defining the Relationships Between Moisture Content and Shortwave Infrared Reflectance of Beach Sands
 Résumé:To study the relationship between the short-wavelength infrared reflectance and the moisture content in the beach, we conducted a rigorous analysis using regression models under different parameter settings defined by band selection, average grain size, and sand mineralogy. The spectral reflectance data were collected by a hand-held spectrometer with 3–6 nm spectral resolution. The grain sizes measured from 0.15 to 0.92 mm, with an average of 0.75 mm. The mineral components were Quartz–Alkali Feldspar–Plagioclase and Calcite-Quartz-Alkali Feldspar-Plagioclase. We found the best spectral bands were located at 1400, 1900, and 2200 nm. The regression model on these selected bands yielded an R-squared over 0.74 and RMSE lower than 0.05. We expect this study to contribute toward understanding the spectral response of beach sand with regard to its moisture content more clearly as we also consider its mineral composition and grain size. Auteurs: Haein Shin;Jaehyung Yu;Yongsik Jeong;Lei Wang;Dong-Yoon Yang; Apparue dans: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing Date publication: 10.-2017, volume: 10, issue:10, pages: 4512 - 4521 Editeur: IEEE Document complet vers site de l'éditeur
» Cavity-Backed Proximity-Coupled Reconfigurable Microstrip Antenna With Agile Polarizations and Steerable Beams
 Résumé:A major challenge for a combined reconfigurable antenna is to realize both polarization switching and beam steering independently in a compact antenna structure. A cavity-backed proximity-coupled reconfigurable microstrip antenna proposed in this communication provides an efficient solution. Beam lead p-i-n diodes DSM8100–000 are employed as switching elements to achieve reconfiguration. Three different linear polarizations (0°, 45°, and 90°) are realized by switching the diodes on a proximity-coupled feed network. For each polarization state, the main beam can be steered to three directions by using a reconfigurable parasitic-element network. The parasitic-element network is printed on the same plane of the radiating patch, thereby making the antenna compact. This antenna has nine different working modes, and for all the working modes, the reflection coefficients are below −10 dB with the measured realized gains ranging from 7.2 to 8.1 dBi. Auteurs: Shu-Lin Chen;Pei-Yuan Qin;Can Ding;Y. Jay Guo; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 10.-2017, volume: 65, issue:10, pages: 5553 - 5558 Editeur: IEEE Document complet vers site de l'éditeur
» Celestial Signals: Are Low-Noise Amplifiers the Future for Millimeter-Wave Radio Astronomy Receivers?
 Résumé:In this article, we compare LNA and SIS mixer technologies, specifically addressing the frequency range of 75-110 GHz (designated the W-band), which is of relevance to ALMA and also for wider use. We briefly describe the principles of operation for each technology as well as typical instrumentation specifications such as device and system noise, bandwidth, and stability. Auteurs: David Cuadrado-Calle;Danielle George;Brian Ellison;Gary A. Fuller;Keiran Cleary; Apparue dans: IEEE Microwave Magazine Date publication: 10.-2017, volume: 18, issue:6, pages: 90 - 99 Editeur: IEEE Document complet vers site de l'éditeur
 Résumé:Discusses the importance of an education despite the challenges that people may face in order to achieve their career goals. Auteurs: David Eng; Apparue dans: IEEE Industry Applications Magazine Date publication: 10.-2017, volume: 23, issue:5, pages: 76 - 77 Editeur: IEEE Document complet vers site de l'éditeur
» Change Detection Based on Deep Siamese Convolutional Network for Optical Aerial Images
 Résumé:In this letter, we propose a novel supervised change detection method based on a deep siamese convolutional network for optical aerial images. We train a siamese convolutional network using the weighted contrastive loss. The novelty of the method is that the siamese network is learned to extract features directly from the image pairs. Compared with hand-crafted features used by the conventional change detection method, the extracted features are more abstract and robust. Furthermore, because of the advantage of the weighted contrastive loss function, the features have a unique property: the feature vectors of the changed pixel pair are far away from each other, while the ones of the unchanged pixel pair are close. Therefore, we use the distance of the feature vectors to detect changes between the image pair. Simple threshold segmentation on the distance map can even obtain good performance. For improvement, we use a $k$ -nearest neighbor approach to update the initial result. Experimental results show that the proposed method produces results comparable, even better, with the two state-of-the-art methods in terms of F-measure. Auteurs: Yang Zhan;Kun Fu;Menglong Yan;Xian Sun;Hongqi Wang;Xiaosong Qiu; Apparue dans: IEEE Geoscience and Remote Sensing Letters Date publication: 10.-2017, volume: 14, issue:10, pages: 1845 - 1849 Editeur: IEEE Document complet vers site de l'éditeur
» Channel Capacity Approach to Hyperspectral Band Subset Selection
 Résumé:This paper develops an information theoretical approach using channel capacity as a criterion for band subset selection (BSS). It formulates a BSS problem as a channel capacity problem by constructing a band channel with the original full band set as a channel input space, a selected band subset as a channel output space and the channel transition specified by band discrimination between original bands and selected bands. Then BSS is selected by Blahut's algorithm that iteratively finds a best possible input space that yields the maximal channel capacity. As a result, there is no need of band prioritization and interband decorrelation generally required by traditional band selection (BS). Two iterative algorithms are developed for finding an optimal BSS, sequential channel capacity BSS (SQ-CCBSS) and successive CCBSS (SC-CCBSS), both of which avoid an exhaustive search for all possible band subset combinations. Experimental results demonstrate that using CCBSS-selected band subsets produce quite different and interesting results from multiple bands selected by traditional single BS (SBS) based methods. Auteurs: Chein-I Chang;Li-Chien Lee;Bai Xue;Meiping Song;Jian Chen; Apparue dans: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing Date publication: 10.-2017, volume: 10, issue:10, pages: 4630 - 4644 Editeur: IEEE Document complet vers site de l'éditeur
» Channel Detection in Coded Communication
 Résumé:The problem of block-coded communication where in each block the channel law belongs to one of two disjoint sets is considered. The decoder is aimed to decode only messages that have undergone a channel from one of the sets, and thus has to detect the set which contains the underlying channel. The simplified case where each of the sets is a singleton is studied first. The decoding error, false alarm, and misdetection probabilities of a given code are defined, and the optimum detection/decoding rule in a generalized Neyman-Pearson sense is derived. Sub-optimal detection/decoding rules are also introduced which are simpler to implement. Then, various achievable bounds on the error exponents are derived, including the exact single-letter characterization of the random coding exponents for the optimal detector/decoder. The random coding analysis is then extended to general sets of channels, and an asymptotically optimal detector/decoder under a worst case formulation of the error probabilities is derived, as well as its random coding exponents. The case of a pair of binary symmetric channels is discussed in detail. Auteurs: Nir Weinberger;Neri Merhav; Apparue dans: IEEE Transactions on Information Theory Date publication: 10.-2017, volume: 63, issue:10, pages: 6364 - 6392 Editeur: IEEE Document complet vers site de l'éditeur
» Channel Equalization and Interference Analysis for Uplink Narrowband Internet of Things (NB-IoT)
 Résumé:We derive the uplink system model for In-band and Guard-band narrowband Internet of Things (NB-IoT). The results reveal that the actual channel frequency response (CFR) is not a simple Fourier transform of the channel impulse response, due to sampling rate mismatch between the NB-IoT user and long term evolution (LTE) base station. Consequently, a new channel equalization algorithm is proposed based on the derived effective CFR. In addition, the interference is derived analytically to facilitate the co-existence of NB-IoT and LTE signals. This letter provides an example and guidance to support network slicing and service multiplexing in the physical layer. Auteurs: Lei Zhang;Ayesha Ijaz;Pei Xiao;Rahim Tafazolli; Apparue dans: IEEE Communications Letters Date publication: 10.-2017, volume: 21, issue:10, pages: 2206 - 2209 Editeur: IEEE Document complet vers site de l'éditeur

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