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Publications dans les journaux scientifiques dans le domaine de l'ingénierie : 10-2017 trié par par titre, page: 3
» 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
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» 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
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» 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
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» 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
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» 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
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» 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
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» 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
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» 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
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» Beam-Domain Full-Duplex Massive MIMO: Realizing Co-time Co-frequency Uplink and Downlink Transmission in the Cellular System
Résumé:
Co-time co-frequency uplink and downlink (CCUD) transmission was considered challenging in the cellular system due to the strong self-interference (SI) between the transmitter and receiver of base station (BS). In this paper, by investigating the beam-domain representation of channels based on the basis expansion model, we propose a beam-domain full-duplex (BDFD) massive multiple-input multiple-output (MIMO) scheme to make the CCUD transmission possible. The key idea of the BDFD scheme lies in intelligently scheduling the uplink and downlink user equipment (UE) based on the beam-domain distributions of their associated channels to mitigate SI and enhance transmission efficiency. We show that the BDFD scheme achieves significant savings in uplink/downlink training resource and achieves uplink and downlink sum capacities simultaneously as the number of BS antennas approaches infinity. The superiority of the BDFD scheme over the traditional time-division duplex (TDD)/frequency-division duplex (FDD) massive MIMO is evaluated through simulation for the macrocell environment. The results show that the spectral efficiency gain can even exceed 2 $\times$ in the specific scenarios, since the BDFD scheme utilizes the time-frequency resource more efficiently in both the training and data transmission phases.
Auteurs: Xiaochen Xia;Kui Xu;Dongmei Zhang;Youyun Xu;Yurong Wang;
Apparue dans: IEEE Transactions on Vehicular Technology
Date publication: 10.-2017, volume: 66, issue:10, pages: 8845 - 8862
Editeur: IEEE
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» Beamforming in Traffic-Aware Two-Way Relay Systems With Channel Estimation Error and Feedback Delay
Résumé:
This paper presents a comprehensive performance analysis of a multi-antenna-based traffic-aware two-way relay system with unavoidable imperfections in channel state information (CSI) under Nakagami-m fading. Herein, we employ transmit/receive beamforming at source nodes and analog network coding (ANC) at the relay node in the presence of CSI imperfections due to channel estimation errors (CEE) and feedback delay. With such a practical setup, we first deduce the pertinent instantaneous end-to-end signal-to-noise ratios (SNRs) after performing partial self-interference cancellation. Then, by imposing asymmetric traffic requirements in two opposite directions, we conduct an accurate analysis of overall outage probability (OOP) of the considered system. We further derive a tight lower bound on OOP that has a simple and compact closed-form representation. Moreover, based on the asymptotic OOP expression at high SNR, we examine the achievable diversity order of the system. In addition, we acquire an upper bound expression of ergodic sum-rate (ESR) and simplify it further in useful compact form for high SNR regime. Besides, we investigate the optimization problems of relay position to minimize the OOP and to maximize the ESR. Numerical and simulation results validate our theoretical analysis and highlight the impact of CEE and feedback delay under various traffic patterns on the overall system performance.
Auteurs: Devendra Singh Gurjar;Prabhat Kumar Upadhyay;Daniel Benevides da Costa;Rafael Timóteo de Sousa;
Apparue dans: IEEE Transactions on Vehicular Technology
Date publication: 10.-2017, volume: 66, issue:10, pages: 8807 - 8820
Editeur: IEEE
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» 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
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» Behavior Recognition Based on Wi-Fi CSI: Part 1
Résumé:
The articles in this special feature provides address behavior recognition based on Wi-Fi channel state estimation (CSI). Human behavior recognition is the core technology that enables a wide variety of human-machine systems and applications (e.g., healthcare, smart homes, and fitness tracking). Traditional approaches mainly use cameras, radars, or wearable sensors. However, all these approaches have certain disadvantages. Examines both the benefits and drawbacks of these technologies and reports on new areas of development for the future.
Auteurs: Bin Guo;Yingying Jennifer Chen;Nic Lane;Yunxin Liu;Zhiwen Yu;
Apparue dans: IEEE Communications Magazine
Date publication: 10.-2017, volume: 55, issue:10, pages: 90 - 90
Editeur: IEEE
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» 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
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» 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
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» 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
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» 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
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» 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
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» 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
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» 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
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» 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
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» 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
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» 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
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» Biomechanical Design of a Novel Flexible Exoskeleton for Lower Extremities
Résumé:
This paper presents a novel wearable walking assistance device for the elderly to provide physical gait assistance. The wearable device, to be worn invisibly underneath clothes, not only fits tightly to the wearer's lower body, but also comfortably transmits assistive torque to the wearer's hip/knee joint. To overcome deficiencies in the usability of conventional wearable walking assistance devices, two novel features are proposed: 1) a unique flexible support frame that withstands vertical loads while maintaining the natural curvature of the wearer's lower body; and 2) a kinematically similar anthropomorphic joint that minimizes the unintended resistance force during the wearer's usual motions. The developed wearable walking assistance device based on these features was verified by simulations and experiments whose results are described.
Auteurs: Younbaek Lee;Yong-Jae Kim;Jongwon Lee;Minhyung Lee;Byungjune Choi;Jeonghun Kim;Young Jin Park;Jungyun Choi;
Apparue dans: IEEE/ASME Transactions on Mechatronics
Date publication: 10.-2017, volume: 22, issue:5, pages: 2058 - 2069
Editeur: IEEE
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» 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
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» 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
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» 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
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» Block Distributed Compressive Sensing-Based Doubly Selective Channel Estimation and Pilot Design for Large-Scale MIMO Systems
Résumé:
The doubly selective (DS) channel estimation in the large-scale multiple-input multiple-output (MIMO) systems is a challenging problem due to the large number of the channel coefficients to be estimated, which requires unaffordable and prohibitive pilot overhead. In this paper, first we conduct the analysis about the common sparsity of the basis expansion model (BEM) coefficients among all the BEM orders and all the transmit–receive antenna pairs. Then, a novel pilot pattern is proposed, which inserts the guard pilots to deal with the intercarrier interference under the superimposed pilot pattern. Moreover, by exploiting the common sparsity of the BEM coefficients among different BEM orders and different antennas, we propose a block distributed compressive sensing-based DS channel estimator for the large-scale MIMO systems. Its structured sparsity leads to the reduction of the pilot overhead under the premise of guaranteeing the accuracy of the estimation. Furthermore, taking consideration of the block structure, a pilot design algorithm referred to as block discrete stochastic optimization is proposed. It optimizes the pilot positions by reducing the coherence among different blocks of the measurement matrix. Besides, a linear smoothing method is extended to large-scale MIMO systems to improve the accuracy of the estimation. Simulation results verify the performance gains of our proposed estimator and the pilot design algorithm compared with the existing schemes.
Auteurs: Bo Gong;Lin Gui;Qibo Qin;Xiang Ren;Wen Chen;
Apparue dans: IEEE Transactions on Vehicular Technology
Date publication: 10.-2017, volume: 66, issue:10, pages: 9149 - 9161
Editeur: IEEE
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» Block Sparse Bayesian Learning-Based NB-IoT Interference Elimination in LTE-Advanced Systems
Résumé:
Narrowband Internet-of-Things (NB-IoT) is one of the emerging 5G technologies, but might introduce narrowband interference (NBI) to existing broadband systems, such as long-term evolution advanced (LTE-A) systems. Thus, the mitigation of the NB-IoT interference to LTE-A is an important issue for the harmonic coexistence and compatibility between 4G and 5G. In this paper, a newly emerged sparse approximation technique, block sparse Bayesian learning (BSBL), is utilized to estimate the NB-IoT interference in LTE-A systems. The block sparse representation of the NBI is constituted through the proposed temporal differential measuring approach, and the BSBL theory is utilized to recover the practical block sparse NBI. A BSBL-based method, partition estimated BSBL, is proposed. With the aid of the estimated block partition beforehand, the Bayesian parameters are obtained to yield the NBI estimation. The intra-block correlation (IBC) is considered to facilitate the recovery. Moreover, exploiting the inherent structure of the identical IBC matrix, another method of informative BSBL is proposed to further improve the accuracy, which does not require prior estimation of the block partition. Reported simulation results demonstrate that the proposed methods are effective in canceling the NB-IoT interference in LTE-A systems, and significantly outperform other conventional methods.
Auteurs: Sicong Liu;Fang Yang;Jian Song;Zhu Han;
Apparue dans: IEEE Transactions on Communications
Date publication: 10.-2017, volume: 65, issue:10, pages: 4559 - 4571
Editeur: IEEE
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» 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
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» 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
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» 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
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» 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
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» 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
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» Boundary Vibration Control of Variable Length Crane Systems in Two-Dimensional Space With Output Constraints
Résumé:
A variable length crane system under the external disturbances and constraints is studied in the two-dimensional space. The dynamical analysis of the cable system considers the variable length, variable tension, variable speed, and the coupled vibrations of the cable in longitudinal-transverse directions. Considering output constraint problems, boundary control algorithms with output signal barriers are designed and acted on the boundary of the cable to reduce the coupled vibrations of the flexible crane cable, and to ensure the stability of the system in theory. Effectiveness and performance of the proposed control schemes are depicted via several simulation examples.
Auteurs: Xiuyu He;Wei He;Jing Shi;Changyin Sun;
Apparue dans: IEEE/ASME Transactions on Mechatronics
Date publication: 10.-2017, volume: 22, issue:5, pages: 1952 - 1962
Editeur: IEEE
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» 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
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» 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
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» 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
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» 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
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» 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
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» 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
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» Broadband Tunable Add/Drop Filters Based on Dielectric Double-Disk Microcavities
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
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» 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
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» 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
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» 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
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» 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
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» 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
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» 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
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» 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
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» Cancelling out Skull-Induced Aberrations: Analysis of Acoustic Metamaterials Using Neural Networks
Résumé:
During investigations on the use of acoustic metamaterials for the correction of skull-induced aberrations on the ultrasonic beam for neurological applications, inconsistencies in the results reported in the literature have been found. Stemming from these discrepancies, an analytical model is introduced in this study in an attempt to model the behavior of the metamaterial by using the Method of the Reciprocal Theorem. Its inefficacy in explaining the observed phenomenon is proved and, consequently, an engineering solution is proposed that allows for the mathematical modelling of the observed discrepancies with a precision of approximately 90% by means of a new Neural Network architecture called Convolutional Modelling Network.
Auteurs: Carlos Cueto;Basil Mohammed Al Hadithi;
Apparue dans: IEEE Latin America Transactions
Date publication: 10.-2017, volume: 15, issue:10, pages: 1948 - 1959
Editeur: IEEE
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» 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
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» Capability-Based Security Enforcement in Named Data Networking
Résumé:
Named data networking (NDN) enhances traditional IP networking by supporting in-network content caching for better bandwidth usage and location-independent data accesses for multi-path forwarding. However, NDN also brings new security challenges. For example, an adversary can arbitrarily inject packets to NDN to poison content cache, or access content packets without any restrictions. We propose capability-based security enforcement architecture (CSEA), a capability-based security enforcement architecture that enables data authenticity in NDN in a distributed manner. CSEA leverages capabilities to specify the access rights of forwarded packets. It allows NDN routers to verify the authenticity of forwarded packets, and throttles flooding-based DoS attacks from unsolicited packets. We further develop a lightweight one-time signature scheme for CSEA to ensure the timeliness of packets and support efficient verification. We prototype CSEA on the open-source CCNx platform, and evaluate CSEA via testbed and Planetlab experiments. Our experimental results show that CSEA only incurs around 4% of additional delays in retrieving data packets.
Auteurs: Qi Li;Patrick P. C. Lee;Peng Zhang;Purui Su;Liang He;Kui Ren;
Apparue dans: IEEE/ACM Transactions on Networking
Date publication: 10.-2017, volume: 25, issue:5, pages: 2719 - 2730
Editeur: IEEE
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» 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
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» 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
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» 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
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» 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
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» 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
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» 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
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» 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
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» Carrier Frequency Offset Estimation in Uplink OFDMA Systems: An Approach Relying on Sparse Recovery
Résumé:
This paper proposes a novel blind carrier frequency offset (CFO) estimator, namely the sparse recovery assisted CFO (SR-CFO) estimator, for the uplink orthogonal frequency-division multiple access (OFDMA) systems. By exploiting the sparsity embedded in the OFDMA data, the CFO estimation is formulated as an optimization problem of sparse recovery with high-resolution. Meanwhile, in order to enhance the estimation accuracy of CFOs, background noise and sampling errors are mitigated by exploiting the structure of the noise covariances matrix in the transformed observation data, and the asymptotic distribution of the sampling errors. Furthermore, we propose an approach for deriving the regularization parameter used by the SR-CFO estimator, so as to control the tradeoff between the data fitting error and the sparsity of solution. The performance of the proposed SR-CFO estimator along with other four existing estimators is investigated and compared. Numerical results show that the proposed SR-CFO estimator is superior to the state-of-the-art estimators in terms of the estimation reliability.
Auteurs: Min Huang;Lei Huang;Chongtao Guo;Peichang Zhang;Jihong Zhang;Lie-Liang Yang;
Apparue dans: IEEE Transactions on Vehicular Technology
Date publication: 10.-2017, volume: 66, issue:10, pages: 9592 - 9597
Editeur: IEEE
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» 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
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» 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
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» 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
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» 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
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» 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
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» Challenge Your Limits [Pathways]
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
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» Challenges in User Modeling and Personalization
Résumé:
Personalization has a long history, dating back to the “master-apprentice” approach of individual tutoring that sought to pass on knowledge and skills from one generation to the next. Through user modeling and adaptation, we try to capture the tutor’s human intelligence and turn it into artificial intelligence. Over the last decades, this research has evolved from an expert-driven approach toward a data-driven approach. This evolution comes with an interesting challenge: How can we continue to understand what an automated tutor is doing when the process of collecting and interpreting data about users is fully automated and the adaptation and recommendation decisions are “deduced” from individual users’ behavior as well as the behavior of all users combined? This article discusses the challenges of scrutability, repeatability, and meta-adaptation (aka adaptation of the adaptation), important research issues for the coming years.
Auteurs: Paul De Bra;
Apparue dans: IEEE Intelligent Systems
Date publication: 10.-2017, volume: 32, issue:5, pages: 76 - 80
Editeur: IEEE
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» Challenges of Sentiment Analysis for Dynamic Events
Résumé:
Efforts to assess people’s sentiments on Twitter have suggested that Twitter could be a valuable resource for studying political sentiment and that it reflects the offline political landscape. Many opinion mining systems and tools provide users with people’s attitudes toward products, people, or topics and their attributes/aspects. However, although it may appear simple, using sentiment analysis to predict election results is difficult, since it is empirically challenging to train a successful model to conduct sentiment analysis on tweet streams for a dynamic event such as an election. This article highlights some of the challenges related to sentiment analysis encountered during monitoring of the presidential election using Kno.e.sis’s Twitris system.
Auteurs: Monireh Ebrahimi;Amir Hossein Yazdavar;Amit Sheth;
Apparue dans: IEEE Intelligent Systems
Date publication: 10.-2017, volume: 32, issue:5, pages: 70 - 75
Editeur: IEEE
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» 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
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» 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
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» 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
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» 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
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» Channel Equalization and Phase Noise Compensation Free DAPSK-OFDM Transmission for Coherent PON System
Résumé:
Channel equalization and phase noise compensation are required in coherent optical orthogonal frequency-division multiplexing (CO-OFDM) transmission systems for reliable performance. In general, redundant data such as training symbols and pilot tones are necessary for channel and phase noise estimation in quadrature amplitude modulation (QAM) based CO-OFDM systems, which reduces the spectral efficiency of the system. Especially, in the coherent passive optical network (PON), the redundancy increases as the number of subscribers increases. In this letter, we propose a differential amplitude shift keying (DAPSK)-based CO-OFDM transmission for PON system, which does not require channel equalization and phase noise compensation processes. The proposed DAPSK-based CO-OFDM transmission was experimentally demonstrated, and the performance according to receiver launched power and the number of subcarriers was compared with QAM-based CO-OFDM.
Auteurs: Kyoung-Hak Mun;Sang-Min Jung;Soo-Min Kang;Sang-Kook Han;
Apparue dans: IEEE Photonics Journal
Date publication: 10.-2017, volume: 9, issue:5, pages: 1 - 9
Editeur: IEEE
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» Channel Estimation for Multicell Multiuser Massive MIMO Uplink Over Rician Fading Channels
Résumé:
Pilot contamination (PC) is a major problem in massive multiple-input multiple-output (MIMO) systems. This paper proposes a novel channel estimation scheme for such a system in Rician fading channels. First, the possible angle of arrivals (AOAs) of users served by a base station (BS) are derived by exploiting the channel statistical information, assuming a traditional pilot structure, where the pilots for the same-cell users are orthogonal but are identical for the same-indexed users from different cells. Although, with this pilot structure, the channel state information (CSI) derived contains CSI from other-cell users caused by PC, the line-of-sight (LOS) component of the desired user is PC-free when the number of antennas equipped at the BS is large. Then, based on the AOAs and the contaminated CSI, the LOS component of each user served by a BS is estimated, and data are detected by using the derived LOS components. Finally, the decoded data are used to update the CSI estimate via an iterative process. The achievable spectral efficiency of the proposed scheme is analyzed in detail, and simulation results are presented to compare the performance of the proposed scheme with that of three existing schemes.
Auteurs: Liang Wu;Zaichen Zhang;Jian Dang;Jiangzhou Wang;Huaping Liu;Yongpeng Wu;
Apparue dans: IEEE Transactions on Vehicular Technology
Date publication: 10.-2017, volume: 66, issue:10, pages: 8872 - 8882
Editeur: IEEE
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» Channel Estimation for Optical-OFDM-Based Multiuser MISO Visible Light Communication
Résumé:
A least squares-based channel estimation algorithm is proposed for optical orthogonal frequency division multiplexing-based multiuser multiple input single output visible light communications. The pilot sequence and pilot tones are optimized to derive the minimum-mean-square error of the channel estimation. Each user estimates the channel independently, and sends the estimates of the channels to the transmitter. Based on the estimated channels, zero-forcing precoding is applied at the transmitter to achieve the spatial multiplexing gain. The simulated performances of channel estimation and data detection are provided.
Auteurs: Liang Wu;Julian Cheng;Zaichen Zhang;Jian Dang;Huaping Liu;
Apparue dans: IEEE Photonics Technology Letters
Date publication: 10.-2017, volume: 29, issue:20, pages: 1727 - 1730
Editeur: IEEE
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» Channel Selection for Secondary Users in Decentralized Network of Unknown Size
Résumé:
In this letter, the challenge of optimal channel selection among the non-cooperative and unknown number of secondary (i.e., unlicensed) users (SUs) in the decentralized network is addressed. The proposed scheme consists of two phases: estimation and ranking (ER) phase and high throughput (HT) phase. In the ER phase, each SU chooses the channel randomly. Based on the sensing and collision outcomes, the proposed mathematical expression allows the SUs to independently estimate the channel ranking and the number of active SUs, $U$ . In the HT phase, the SUs follow collision-free hopping to exploit top $U$ channels. An upper bound on the time required for the SU orthogonalization in the HT phase, loss in throughput, and number of channel switchings are derived. Theoretical analysis and simulation results validate the superiority of the proposed scheme over existing state-of-the-art schemes.
Auteurs: Rohit Kumar;Sumit J. Darak;Ankit Yadav;Ajay K. Sharma;Rajiv K. Tripathi;
Apparue dans: IEEE Communications Letters
Date publication: 10.-2017, volume: 21, issue:10, pages: 2186 - 2189
Editeur: IEEE
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» Characteristics of Doped n+ GaAs Thermopile-Based RF MEMS Power Sensors for MMIC Applications
Résumé:
This letter presents characteristics of thermopile-based radio frequency microelectromechanical system (RF MEMS) power sensors with different doped n+ GaAs concentrations, in order to improve sensitivity and signal-noise ratio (SNR). These sensors employ the conversion principle of RF power-heat-electricity, where two materials of AuGeNi/Au and n+ GaAs are designed to constitute two arms of the thermopile. The effects of four doping concentrations of n+ GaAs on the sensitivity and SNR of the power sensors are investigated. The RF MEMS power sensors are fabricated by a GaAs monolithic microwave integrated circuit (MMIC)-compatible process. Experiments show that these power sensors produce return losses of less than −28.3 dB up to 20 GHz. For the doped n+ GaAs concentrations of $2.4\times 10^{{18}}$ , $8.5\times 10^{{17}}$ , $3.2\times 10^{{17}}$ , and $1.9\times 10^{{17}}$ cm−3, measured sensitivities are about 84.10, 101.04, 209.82, and $395.52~\mu \text{V}$ /mW at 1 GHz and about 45.87, 54.11, 104.15, and $212.53~\mu \text{V}$ /mW at 20 GHz, respectively, while the resulting SNR are about $4.27\times 10^{{6}}$ , $3.08 \times 10^{{6}}$ , $3.91\times 10^{{6}}$ , and $5.70\times 10^{{6}}~\text{W}^{{-1}}$ at 1 GHz and about $2.33\times 10^{{6}}, 1.65\times 10^{{6}}$ , $1.94\times 10^{{6}}$ , and $3.06\times 10^{{6}}~\text{W}^{{-1}}$ at 20 GHz, respectively. With the decrease of doping concentration, the sensitivity increases but the SNR decreases first and then increases.
Auteurs: Zhiqiang Zhang;Xiaoping Liao;
Apparue dans: IEEE Electron Device Letters
Date publication: 10.-2017, volume: 38, issue:10, pages: 1473 - 1476
Editeur: IEEE
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» Characteristics of Electromagnetic Disturbance for Intelligent Component Due to Switching Operations via a 1100 kV AC GIS Test Circuit
Résumé:
Switching operation of the disconnector in gas-insulated switchgear (GIS) results in very fast transient overvoltage in GIS pipes. In a smart substation, this process induces disturbance voltage on the port of the intelligent component fixed on GIS pipes or placed in the local cabinet nearby, which then may lead to the failure of the equipment. The experimental results of the port disturbance voltage during the switching operation via a 1100 kV test circuit are first reported in this paper. The test arrangement, including both 70 opening operations and 70 closing operations, had been performed. The influences of different grounding schemes of cable shield on port disturbance had been investigated. Three different cases of the terminal load had also been considered: open circuit, short circuit, and 50 Ω. Over 100 000 micro-pulses had been extracted from the disturbance voltage waveforms. The waveform characteristics including peak voltage, rise-time, oscillation frequency, and decaying had been obtained by statistical analysis of these micro-pulses. Furthermore, the differences between measured waveforms and the IEC 61000-4-18 immunity test standard waveform had been discussed.
Auteurs: Heng-Tian Wu;Xiang Cui;Xiao-Fan Liu;Chong-Qing Jiao;Rong Hu;Wei-Jiang Chen;Lei Wang;
Apparue dans: IEEE Transactions on Power Delivery
Date publication: 10.-2017, volume: 32, issue:5, pages: 2228 - 2237
Editeur: IEEE
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» Characteristics Optimization of the Resonant Detector for Mössbauer Spectroscopy Using Resonance 57Fe
Résumé:
This paper considers the converter materials having different mean thickness, isomeric chemical shift, and various cationic surroundings of the iron atoms in the converter matrix for resonance detectors. The influence of the converter material parameters on the characteristics of the Mössbauer spectra taken by the resonance detector has been estimated. The value of resonance absorption, experimental linewidth, and the measurement time of the Mössbauer spectra has been calculated taking into account the material converter parameters. It has been found that beryllium ferrocyanide with efficient thickness equal to 2 is the most appropriate converter for emission experiments, and potassium-magnesium ferrocyanide with effective thickness equal to 4 proves to be optimal for transmission Mössbauer experiments.
Auteurs: Dmitry Alekseevich Sarychev;Nokolay Mikhailovich Novikovskiy;Viacheslav Vladimirovich Stashenko;Vladimir Vasilievich Kitaev;Dmitry Nikolaevich Sivokon;Aleksander Andreevich Spivakov;
Apparue dans: IEEE Transactions on Nuclear Science
Date publication: 10.-2017, volume: 64, issue:10, pages: 2729 - 2732
Editeur: IEEE
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» Characterization and Evaluation of the State-of-the-Art 3.3-kV 400-A SiC MOSFETs
Résumé:
Since their introduction, the SiC-based semiconductors have been of special interest to the field of power electronics, enabling increase in system efficiency, maximum operating temperature, and power density. In higher voltage range, these semiconductors are at early stage of development and yet are not commercialized. This paper investigates state-of-the-art noncommercialized 3.3-kV 400-A full-SiC MOSFETs where for the first time such MOSFETs are thoroughly characterized and their performance is evaluated and compared against similar rating Si counterparts. Extensive static and dynamic characterizations are done with emphasize on enabling conduction and switching loss calculation in any target application. I-V curves for MOSFET and Shottky-barrier diode (SBD), RDSon, C-V curves and threshold voltages are addressed by measurement at different temperatures. Moreover, the SiC MOSFETs are tested in chopper circuit with an inductive load for measurement of switching losses. This is done at 2-kV bus voltage from 50 up to 400 A load current. Finally, simulations are done in MATLAB/Simulink to evaluate the performance of 3.3-kV 400-A modules in medium-voltage high-power industrial drive application. The case study shows advantages of the 3.3-kV SiC MOSFET technology over 3.3-kV Si IGBTs and 1.7-kV SiC MOSFETs from efficiency, installed die area and power density points of view.
Auteurs: Alinaghi Marzoughi;Jun Wang;Rolando Burgos;Dushan Boroyevich;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 10.-2017, volume: 64, issue:10, pages: 8247 - 8257
Editeur: IEEE
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» Characterization of $\gamma $ -Ray Cross Talk in Cherenkov-Based Detectors for Active Interrogation Imaging Applications
Résumé:
In imaging arrays, the sensors are typically packed as tightly as possible to maximize spatial resolution, which leads to detector-to-detector scatter, or cross talk, adding to image noise and hindering contrast. In this paper, we compare custom-made quartz-based Cherenkov detectors with an inherent energy threshold to low-energy photons to standard sodium iodide detectors, which are typically used for x-ray detection due to their efficiency and spectroscopic capabilities. In particular, we evaluate pulse pileup and cross talk effects in high-flux applications. The quartz detectors, while having reduced intrinsic efficiency, outperform the sodium iodide with regards to pileup and cross talk. Simulation further shows that even at a 4 mm edge-to-edge separation, cross talk contributes less than 2% of the total signal in Cherenkov detectors.
Auteurs: Joseph Harms;Paul B. Rose;Anna Erickson;
Apparue dans: IEEE Sensors Journal
Date publication: 10.-2017, volume: 17, issue:20, pages: 6707 - 6715
Editeur: IEEE
Document complet vers site de l'éditeur
 
» Characterization of $\gamma $ -Ray Cross Talk in Cherenkov-Based Detectors for Active Interrogation Imaging Applications
Résumé:
In imaging arrays, the sensors are typically packed as tightly as possible to maximize spatial resolution, which leads to detector-to-detector scatter, or cross talk, adding to image noise and hindering contrast. In this paper, we compare custom-made quartz-based Cherenkov detectors with an inherent energy threshold to low-energy photons to standard sodium iodide detectors, which are typically used for x-ray detection due to their efficiency and spectroscopic capabilities. In particular, we evaluate pulse pileup and cross talk effects in high-flux applications. The quartz detectors, while having reduced intrinsic efficiency, outperform the sodium iodide with regards to pileup and cross talk. Simulation further shows that even at a 4 mm edge-to-edge separation, cross talk contributes less than 2% of the total signal in Cherenkov detectors.
Auteurs: Joseph Harms;Paul B. Rose;Anna Erickson;
Apparue dans: IEEE Sensors Journal
Date publication: 10.-2017, volume: 17, issue:20, pages: 6707 - 6715
Editeur: IEEE
Document complet vers site de l'éditeur
 
» Characterization of $\gamma $ -Ray Cross Talk in Cherenkov-Based Detectors for Active Interrogation Imaging Applications
Résumé:
In imaging arrays, the sensors are typically packed as tightly as possible to maximize spatial resolution, which leads to detector-to-detector scatter, or cross talk, adding to image noise and hindering contrast. In this paper, we compare custom-made quartz-based Cherenkov detectors with an inherent energy threshold to low-energy photons to standard sodium iodide detectors, which are typically used for x-ray detection due to their efficiency and spectroscopic capabilities. In particular, we evaluate pulse pileup and cross talk effects in high-flux applications. The quartz detectors, while having reduced intrinsic efficiency, outperform the sodium iodide with regards to pileup and cross talk. Simulation further shows that even at a 4 mm edge-to-edge separation, cross talk contributes less than 2% of the total signal in Cherenkov detectors.
Auteurs: Joseph Harms;Paul B. Rose;Anna Erickson;
Apparue dans: IEEE Sensors Journal
Date publication: 10.-2017, volume: 17, issue:20, pages: 6707 - 6715
Editeur: IEEE
Document complet vers site de l'éditeur
 
» Characterization of CMOS-MEMS Resonant Pressure Sensors
Résumé:
Comprehensive characterization results of CMOS-microelectromechanical systems resonant pressure sensor are presented. We have extensively evaluated the key performance parameters of our device in terms of quality factor ( $Q$ ) variations under variable conditions of temperature and pressure, characterized by Knudsen number ( $K_{n}$ ). The fundamental frequency of the reported device is 104.3 kHz. Over the full-scale pressure range of 0.1 to 100 kPa and a temperature range of −10 °C to 85 °C, $Q$ from 450 to 62.6 have been obtained. Besides, static variations of the device capacitance have been measured and analyzed with temperature to evaluate the spring softening and the pull-in effects. A nonlinearity analysis has been performed to assess the device stability. Furthermore, a statistical mismatch analysis has been carried out to determine the deviation of resonance with etching time and ascertain maximum device yield. With our in-house back-end of line metal-layer release, this sensor can be monolithically embedded in the same substrate as standard CMOS integrated circuits, resulting in a significant cost and area reduction.
Auteurs: Saoni Banerji;Daniel Fernández;Jordi Madrenas;
Apparue dans: IEEE Sensors Journal
Date publication: 10.-2017, volume: 17, issue:20, pages: 6653 - 6661
Editeur: IEEE
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» Characterization of GigaRad Total Ionizing Dose and Annealing Effects on 28-nm Bulk MOSFETs
Résumé:
This paper investigates the radiation tolerance of 28-nm bulk ${n}$ and ${p}$ MOSFETs up to 1 Grad of total ionizing dose (TID). The radiation effects on this commercial 28-nm bulk CMOS process demonstrate a strong geometry dependence as a result of the complex interplay of oxide and interface charge trapping relevant to the gate-related dielectrics and the shallow trench isolation. The narrowest/longest channel devices have the most serious performance degradation. In addition, ${n}$ MOSFETs present a limited on-current variation and a significant off-current increase, while ${p}$ MOSFETs show a negligible off-current change and a substantial on-current degradation. The postirradiation annealing annihilates or neutralizes oxide trapped positive charges and tends to partly recover the degraded device performance. To quantify the effects of TID and postirradiation annealing, parameters including the threshold voltage, the free carrier mobility, the subthreshold swing, and the drain-induced barrier lowering are extracted.
Auteurs: Chun-Min Zhang;Farzan Jazaeri;Alessandro Pezzotta;Claudio Bruschini;Giulio Borghello;Federico Faccio;Serena Mattiazzo;Andrea Baschirotto;Christian Enz;
Apparue dans: IEEE Transactions on Nuclear Science
Date publication: 10.-2017, volume: 64, issue:10, pages: 2639 - 2647
Editeur: IEEE
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» Characterization of Seafloor Roughness to Support Modeling of Midfrequency Reverberation
Résumé:
A seafloor laser scanner was deployed in the Gulf of Mexico during the 2013 Target and Reverberation Experiment (TREX13). This system collected digital elevation maps at 14 locations along the main reverberation track, and these measurements provide roughness power spectra for modeling seafloor acoustic scattering. The spectra were divided into two regimes according to the mid and high-frequency acoustic measurements made during the experiment. For the wave numbers corresponding to the midfrequency regime (2–4 kHz), the spectra could be approximated using the mean spectral exponent derived from the all of the spectra. With this spectral exponent, the best fit spectral strengths were found to be negatively correlated to the backscatter levels measured at 400 kHz using a multibeam echosounder (MBES). While the scattering mechanisms at 400 kHz are not influenced by the roughness at these low wave numbers, this correlation may be indirectly related to the bioturbation and the spatial variation of the shell content. A more pronounced correlation was found for the high wave numbers, where again a single spectral exponent could be used to a good approximation. In this case, the spectral strengths were also linearly related to the MBES backscattering level but with a positive correlation. For these wave numbers, the roughness is largely influenced by the shell content, which is also the dominant scattering mechanism at 400 kHz. The correlations between the roughness and the MBES measurements provide a means to approximate the seafloor roughness parameters in both wave number regimes throughout the experiment site. For the low wave number spectrum, an alternative approach is also proposed, which uses the spectral parameters for the mean spectrum to approximate the roughness throughout the TREX13 site.
Auteurs: Brian T. Hefner;
Apparue dans: IEEE Journal of Oceanic Engineering
Date publication: 10.-2017, volume: 42, issue:4, pages: 1110 - 1124
Editeur: IEEE
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» Characterization of the CVD Graphene Monolayer as an Active Element of a One-Port Microwave Device
Résumé:
The one-port configuration of a microwave device is the simplest architecture for graphene ultrafast (photo-)resistors, (photo-)diodes, sensors, and photodetectors. Here, this configuration is realized by a segment of coplanar waveguide (CPW) loaded with a CVD graphene monolayer shorted to the ground. The magnitude and phase of the reflection coefficient ( ${S}_{11}$ parameter) measured in the $0.1~\div ~26$ GHz frequency range are presented for undisturbed structures as well as for structures illuminated by white light and electrostatically polarized with the backgate. A simple and robust de-embedding procedure based on the signal flow graph and allowing for a simultaneous extraction of the parameters characterizing the CPW segment and the graphene monolayer is proposed. The graphene impedance at microwave frequencies is in good agreement with the value of dc sheet resistance obtained from van der Pauw measurements. The back-gate voltage modulation is an efficient way to modulate both the dc sheet resistance and the impedance. In particular, the Dirac point can be achieved both at microwave frequencies and at dc. An equivalent circuit model consists of only the resistance and capacitance connected in parallel, because of good quality ohmic contacts and a negligible inductance as a result of low-current flow in high-resistance graphene samples.
Auteurs: Jarosław Judek;Mariusz Zdrojek;Jan Sobieski;Aleksandra Przewłoka;Jerzy K. Piotrowski;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 10.-2017, volume: 64, issue:10, pages: 4340 - 4345
Editeur: IEEE
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» Characterization of Y-Bias Ferrite Materials for Tunable Antenna Applications Using a Partially Filled Rectangular Waveguide
Résumé:
A methodology for measuring the constitutive parameters of a ferrite material is presented. This method can be used to assist the prediction of the properties of tunable antennas that use ferrite material as a substrate or tuning component. A nontraditional characterization method is required due to the general unavailability of samples of a sufficient size to fill the entire cross sections of waveguides appropriate for lower frequencies where gyromagnetic properties are most pronounced, and the difficulty of predicting or approximating the applied bias magnetic field. The proposed method overcomes the limitation of sample size by requiring only partial filling of a rectangular waveguide. It overcomes a lack of knowledge of the bias field by including the field as an unknown to be determined by the extraction process. The required theoretical reflection and transmission coefficients of the partially filled waveguide are determined using a mode-matching technique. A nonlinear least squares method is employed to extract the gyromagnetic material parameters and the bias field using optimization algorithms in MATLAB. The extracted parameters of a representative commercial ferrite obtained from multiple experimental configurations are compared with the values provided by the sample manufacturer to demonstrate the feasibility of this technique.
Auteurs: Junyan Tang;Amin Tayebi;Benjamin Crowgey;Edward J. Rothwell;Balasubramaniam Shanker;Leo C. Kempel;Michael J. Havrilla;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 10.-2017, volume: 65, issue:10, pages: 5279 - 5288
Editeur: IEEE
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» Characterizing Transmission Loss Variability During the Target and Reverberation Experiment 2013
Résumé:
A significant driver of uncertainty in sonar performance is the variability in underwater acoustical propagation caused by environmental fluctuations and uncertainty in the position of sources, targets, and receivers. A set of echo-repeat experiments was conducted during the Target and Reverberation Experiment 2013 (TREX13), a sea trial that took place in April to May 2013 in the Gulf of Mexico near Panama City, FL, USA. The variability in measured transmission loss (TL) was characterized using two different methods: Variability with respect to a mean observed TL, and variability with respect to modeled TL. Both one-way and quasi-reciprocal two-way TL measurements at 2250 and 7500 Hz were analyzed to characterize the variability at timescales ranging from less than one second to several days, with the results indicating that the acoustic propagation fluctuates stochastically on all these time scales. The results of statistical tests suggest that the TL variability can be treated as Gaussian fluctuations about a central TL obtained from an acoustic propagation model, with standard deviations of 5 dB over timescales up to one day, or 10 dB over timescales from one to six days.
Auteurs: Cristina D. S. Tollefsen;Sean P. Pecknold;
Apparue dans: IEEE Journal of Oceanic Engineering
Date publication: 10.-2017, volume: 42, issue:4, pages: 1135 - 1145
Editeur: IEEE
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» Charge-Controlled Oscillators and Their Application in Frequency Synthesis
Résumé:
A tunable oscillator, whose frequency is a function of the total charge in the oscillating nodes, is introduced in this brief. Three variants of charge-controlled oscillators (QCOs) that oscillate around 3.6 GHz are presented. The figure-of-merits (FoMs) of these oscillators, obtained from simulation, are 169, 172, and 178 dB, respectively. The measured FoM of the third QCO is 179 dB. We also show that the use of a QCO in a frequency synthesizer eliminates the requirement of an explicit loop filter. Furthermore, an example of an all-digital phase-locked loop based on a QCO is shown.
Auteurs: Roohie Kaushik;Shouri Chatterjee;G. S. Visweswaran;
Apparue dans: IEEE Transactions on Circuits and Systems II: Express Briefs
Date publication: 10.-2017, volume: 64, issue:10, pages: 1127 - 1131
Editeur: IEEE
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» Chip Averaging Chaotic ON–OFF Keying: A New Non-Coherent Modulation for Ultra Wide Band Direct Chaotic Communication
Résumé:
This letter proposes a new adaptive threshold modulation scheme, called chip averaging chaotic ON–OFF keying (CA-COOK). This new scheme is applied to non-coherent modulations in ultra-wideband direct chaotic communication. Mainly, the proposed method deals with the “estimation problem” caused by the bit energy variation of the chaotic carrier signal. This is completed by adopting the Cell Averaging Constant False Alarm Rate paradigm used in radar, and each bit period is divided into several chips, where one of those chips is bearing the information. Bit-error-rate performance in additive-white-Gaussian-noise, two-path Rayleigh, and IEEE802.15.4a office NLOS channel models, is analyzed and compared with well-known and challenging chaos-based communication systems. Simulation results show the effectiveness of the proposed CA-COOK.
Auteurs: Ammar Mesloub;Arezki Boukhelifa;Omar Merad;Said Saddoudi;Arezki Younsi;Mustapha Djeddou;
Apparue dans: IEEE Communications Letters
Date publication: 10.-2017, volume: 21, issue:10, pages: 2166 - 2169
Editeur: IEEE
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» Chip-Scale Near-Field Resonant Power Transfer via Elastic Waves
Résumé:
This paper reports on the proof-of-concept demonstration of an approach for the synthesis of a through package charging and authenticating communication link enabled by GHz-range aluminum nitride (AlN) piezoelectric transducers. The acoustic link is formed by two thickness-mode acoustic transducers placed on the two sides of a packaging substrate. The link leverages the enhancement of energy transfer that occurs at resonance; 1- $\mu \text{m}$ -thick (2.7 GHz) and 6- $\mu \text{m}$ -thick (500 MHz) AlN acoustic links are demonstrated showing substantial enhancement of power transfer efficiencies (PTE) when using thicker AlN substrates. PTEs of −8 dB at 2.7 GHz and −2 dB at 500 MHz are measured for transducers’ size of $1\times 100\times 100~\mu \text{m}^{3}$ and $6\times 100\times 100~\mu \text{m}^{3}$ through 700- and 500- $\mu \text{m}$ -thick silicon substrates, respectively. The experimental values are in very close agreement with the analytical model of the acoustic link. The potential misalignment between the two transducers is the main limitation of this approach. To overcome this challenge, acoustic phased arrays are devised to enable steering of the transmitted beam. Preliminary results on the steering capability demonstrate about 8 dB of improvement in PTE via a two-element array when dealing with a 100- $\mu \text{m}$ misalignment. This paper is the first step toward the development of next-generation high-efficiency and micro-scale power transfer - nits that could energize chips through packages. [2017-0010]
Auteurs: Emad Mehdizadeh;Gianluca Piazza;
Apparue dans: Journal of Microelectromechanical Systems
Date publication: 10.-2017, volume: 26, issue:5, pages: 1155 - 1164
Editeur: IEEE
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» Ciphertext-Only Attack on Phase-Shifting Interferometery-Based Encryption
Résumé:
The phase-shifting interferometry-based (PSI-based) encryption is one of most typical optical encryption systems. In this paper, we demonstrate a new approach to ciphertext-only attack (COA) on PSI-based encryption, revealing that there is serious security risk in PSI-based encryption. With the proposed COA approach, an opponent can crack the ciphertexts directly without use of the keys of the system. This demonstration, as far as our best knowledge, shows the PSI technique is vulnerable to COA for the first time. A series of attack results are shown to demonstrate the feasibility and robustness of the attack method. Our study reveals a critical security issue that should be taken in to account when designing an optical information security system.
Auteurs: Tuo Li;Zongcheng Miao;Yishi Shi;
Apparue dans: IEEE Photonics Journal
Date publication: 10.-2017, volume: 9, issue:5, pages: 1 - 8
Editeur: IEEE
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» Classification and Analysis of Communication Protection Policy Anomalies
Résumé:
This paper presents a classification of the anomalies that can appear when designing or implementing communication protection policies. Together with the already known intra- and inter-policy anomaly types, we introduce a novel category, the inter-technology anomalies, related to security controls implementing different technologies, both within the same network node and among different network nodes. Through an empirical assessment, we prove the practical significance of detecting this new anomaly class. Furthermore, this paper introduces a formal model, based on first-order logic rules that analyses the network topology and the security controls at each node to identify the detected anomalies and suggest the strategies to resolve them. This formal model has manageable computational complexity and its implementation has shown excellent performance and good scalability.
Auteurs: Fulvio Valenza;Cataldo Basile;Daniele Canavese;Antonio Lioy;
Apparue dans: IEEE/ACM Transactions on Networking
Date publication: 10.-2017, volume: 25, issue:5, pages: 2601 - 2614
Editeur: IEEE
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» Classification of Protein Structure Classes on Flexible Neutral Tree
Résumé:
Accurate classification on protein structural is playing an important role in Bioinformatics. An increase in evidence demonstrates that a variety of classification methods have been employed in such a field. In this research, the features of amino acids composition, secondary structure's feature, and correlation coefficient of amino acid dimers and amino acid triplets have been used. Flexible neutral tree (FNT), a particular tree structure neutral network, has been employed as the classification model in the protein structures’ classification framework. Considering different feature groups owing diverse roles in the model, impact factors of different groups have been put forward in this research. In order to evaluate different impact factors, Impact Factors Scaling (IFS) algorithm, which aim at reducing redundant information of the selected features in some degree, have been put forward. To examine the performance of such framework, the 640, 1189, and ASTRAL datasets are employed as the low-homology protein structure benchmark datasets. Experimental results demonstrate that the performance of the proposed method is better than the other methods in the low-homology protein tertiary structures.
Auteurs: Wenzheng Bao;Dong Wang;Yuehui Chen;
Apparue dans: IEEE/ACM Transactions on Computational Biology and Bioinformatics
Date publication: 10.-2017, volume: 14, issue:5, pages: 1122 - 1133
Editeur: IEEE
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» Classification of Schizophrenia Based on Individual Hierarchical Brain Networks Constructed From Structural MRI Images
Résumé:
With structural magnetic resonance imaging (MRI) images, conventional methods for the classification of schizophrenia (SCZ) and healthy control (HC) extract cortical thickness independently at different regions of interest (ROIs) without considering the correlation between these regions. In this paper, we proposed an improved method for the classification of SCZ and HC based on individual hierarchical brain networks constructed from structural MRI images. Our method involves constructing individual hierarchical networks where each node and each edge in these networks represents a ROI and the correlation between a pair of ROIs, respectively. We demonstrate that edge features make significant improvement in performance of SCZ/HC classification, when compared with only node features. Classification performance is further investigated by combining edge features with node features via a multiple kernel learning framework. The experimental results show that our proposed method achieves an accuracy of 88.72% and an area under the receiver operating characteristic (ROC) curve (AUC) of 0.9521 for SCZ/HC classification, which demonstrate that our proposed method is efficient and promising for clinical applications for the diagnosis of SCZ via structural MRI images. Therefore, this paper provides an alternative method for extracting high-order cortical thickness features from structural MRI images for classification of neurodegenerative diseases such as SCZ.
Auteurs: Jin Liu;Min Li;Yi Pan;Fang-Xiang Wu;Xiaogang Chen;Jianxin Wang;
Apparue dans: IEEE Transactions on NanoBioscience
Date publication: 10.-2017, volume: 16, issue:7, pages: 600 - 608
Editeur: IEEE
Document complet vers site de l'éditeur
 
» Closed-Form BER Expressions of QPSK Constellation for Uplink Non-Orthogonal Multiple Access
Résumé:
Non-orthogonal multiple access (NOMA) is an attractive multiple access technique to achieve the optimal system capacity region. A great deal of recent attention has been devoted to the study of the NOMA system capacity performance. However, the exact bit error rate (BER) expressions of NOMA systems have not been derived yet. We provide the exact closed-form BER expressions of the QPSK constellation for an uplink NOMA system over an additive white Gaussian noise channel. Finally, the validity of our derived BER expressions is verified through simulations.
Auteurs: Xiaolu Wang;Fabrice Labeau;Lin Mei;
Apparue dans: IEEE Communications Letters
Date publication: 10.-2017, volume: 21, issue:10, pages: 2242 - 2245
Editeur: IEEE
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» Closed-Form SER Expression for APSK Based on the Kite Structure
Résumé:
In communication systems, amplitude phase shift keying (APSK) arises as a potential solution to mitigate performance degradations due to channel non-linearities. Since it combines the characteristics of PSK and those of amplitude shift keying (ASK), APSK is also likely to be robust in systems influenced by phase noise. It is, therefore, solicited in cascaded systems involving visible light communications (VLC) as the second communication technology. This letter proposes the design of an APSK constellation, based on the kite structure, suitable for such cascaded systems. The constellation design is detailed and the symbol error probability is derived in closed-form. The bit error rate performance is compared with those of quadrature amplitude modulation (QAM) and PSK. Findings reveal that for $ 2\eta = 4$ ( $ \eta $ being the common number of symbols per ring), the proposed APSK scheme has similar performance with ${Q}$ PSK and 4QAM, and, for $2\eta > 8$ , the APSK scheme outperforms the corresponding PSK, making it a good candidate for cascaded VLC systems. Even though the proposed scheme is outperformed by QAM, it gains up to about 5 dB over the PSK for an error rate of $ 10^{-8} $ .
Auteurs: Alain Richard Ndjiongue;Hendrik C. Ferreira;Telex M. N. Ngatched;
Apparue dans: IEEE Communications Letters
Date publication: 10.-2017, volume: 21, issue:10, pages: 2182 - 2185
Editeur: IEEE
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» Closed-Loop Neurostimulators: A Survey and A Seizure-Predicting Design Example for Intractable Epilepsy Treatment
Résumé:
First, existing commercially available open-loop and closed-loop implantable neurostimulators are reviewed and compared in terms of their targeted application, physical size, system-level features, and performance as a medical device. Next, signal processing algorithms as the primary strength point of the closed-loop neurostimulators are reviewed, and various design and implementation requirements and trade-offs are discussed in details along with quantitative examples. The review results in a set of guidelines for algorithm selection and evaluation. Second, the implementation of an inductively-powered seizure-predicting microsystem for monitoring and treatment of intractable epilepsy is presented. The miniaturized system is comprised of two miniboards and a power receiver coil. The first board hosts a 24-channel neurostimulator system on chip [15] fabricated in a $0.13\;\mu \text{m}$ CMOS technology and performs neural recording, on-chip digital signal processing, and electrical stimulation. The second board communicates recorded brain signals as well as signal processing results wirelessly. The multilayer flexible coil receives inductively-transmitted power. The system is sized at 2 $\times$ 2 $\times$ 0.7 $\text{cm}^3$ and weighs 6 g. The approach is validated in the control of chronic seizures in vivo in freely moving rats.
Auteurs: Hossein Kassiri;Sana Tonekaboni;M. Tariqus Salam;Nima Soltani;Karim Abdelhalim;Jose Luis Perez Velazquez;Roman Genov;
Apparue dans: IEEE Transactions on Biomedical Circuits and Systems
Date publication: 10.-2017, volume: 11, issue:5, pages: 1026 - 1040
Editeur: IEEE
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» Cloud-Based Malware Detection Game for Mobile Devices with Offloading
Résumé:
As accurate malware detection on mobile devices requires fast process of a large number of application traces, cloud-based malware detection can utilize the data sharing and powerful computational resources of security servers to improve the detection performance. In this paper, we investigate the cloud-based malware detection game, in which mobile devices offload their application traces to security servers via base stations or access points in dynamic networks. We derive the Nash equilibrium (NE) of the static malware detection game and present the existence condition of the NE, showing how mobile devices share their application traces at the security server to improve the detection accuracy, and compete for the limited radio bandwidth, the computational and communication resources of the server. We design a malware detection scheme with Q-learning for a mobile device to derive the optimal offloading rate without knowing the trace generation and the radio bandwidth model of other mobile devices. The detection performance is further improved with the Dyna architecture, in which a mobile device learns from the hypothetical experience to increase its convergence rate. We also design a post-decision state learning-based scheme that utilizes the known radio channel model to accelerate the reinforcement learning process in the malware detection. Simulation results show that the proposed schemes improve the detection accuracy, reduce the detection delay, and increase the utility of a mobile device in the dynamic malware detection game, compared with the benchmark strategy.
Auteurs: Liang Xiao;Yanda Li;Xueli Huang;XiaoJiang Du;
Apparue dans: IEEE Transactions on Mobile Computing
Date publication: 10.-2017, volume: 16, issue:10, pages: 2742 - 2750
Editeur: IEEE
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» Cluster Synchronization of Coupled Genetic Regulatory Networks With Delays via Aperiodically Adaptive Intermittent Control
Résumé:
In this paper, we study the cluster synchronization of coupled genetic regulatory networks with time-varying delays via aperiodically adaptive intermittent control on some nodes. The network is intermittently coupled and the intra-cluster coupling strength is adaptively adjusted. The graph of the coupling topology of each cluster is only required to have a directed spanning tree. Two cases of delays are considered. In the first case, by using the switching Lyapunov-based function and Razumikhin-type technique, the cluster synchronization criterion is presented which indicates that the cluster synchronization is realized via the aperiodically adaptive intermittent control. The second case is investigated by using the switching Lyapunov functional. Both the cluster synchronization criteria are established by the Linear Matrix Inequalities (LMIs), the lower bound of the aperiodical time span, and the maximum uncontrolled ratio. It is shown that the results are applicable to both the situations that the upper bound of the delay is larger and smaller than the lower bound of the aperiodical coupling and control width. Numerical simulations are carried out to illustrate the theoretical results.
Auteurs: Zhi-Hong Guan;Dandan Yue;Bin Hu;Tao Li;Feng Liu;
Apparue dans: IEEE Transactions on NanoBioscience
Date publication: 10.-2017, volume: 16, issue:7, pages: 585 - 599
Editeur: IEEE
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» Cluster-Aware Virtual Machine Collaborative Migration in Media Cloud
Résumé:
Media cloud has become a promising paradigm for deploying large-scale streaming media applications at a reduced cost. Due to dynamic and diverse demands of users, media cloud presents two crucial characteristics: high resource consumption and dynamic traffic among media servers. Consequently, Virtual Machine (VM) migration in media cloud is highly required to suit varying resource requirements and the dynamic traffic patterns. Moreover, migration of such bandwidth-intensive media applications in media cloud needs cautious handling, especially for the internal traffic of Data Center Networks (DCN). However, existing media cloud resource management schemes or traffic-aware VM deployment approaches are insufficient for media cloud, ignoring the characteristics of either cloud infrastructure or media streaming requirements. In this paper, we propose a cluster-aware VM collaborative migration scheme for media cloud, tightly integrating clustering, placement, and dynamic migration process. The scheme employs a clustering algorithm and a placement algorithm to obtain ideal migration strategies for newly perceived media server clusters, and a migration algorithm to effectively accomplish the migration process of media servers. Evaluation results demonstrate that our scheme can effectively migrate virtual media servers in media cloud, while reducing the total internal traffic in DCN under the resource consumption constraints of media streaming applications.
Auteurs: Weizhan Zhang;Yuxuan Chen;Xiang Gao;Zhichao Mo;Qinghua Zheng;Zongqing Lu;
Apparue dans: IEEE Transactions on Parallel and Distributed Systems
Date publication: 10.-2017, volume: 28, issue:10, pages: 2808 - 2822
Editeur: IEEE
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» Clustered Voltage Balancing Mechanism and Its Control Strategy for Star-Connected Cascaded H-Bridge STATCOM
Résumé:
To explore the clustered voltage balancing mechanism of the star-connected cascaded H-Bridge (SCHB) STATCOM, this paper analyzes the relationship between the active power and the control variables-modulation reference voltages in a dq frame through positive and negative sequence component decomposition. The derived relationship in the dq frame reveals that the negative sequence modulation reference voltage is capable of redistributing the active power among three phases and also the SCHB STATCOM features the clustered voltage self-stabilizing without any additional clustered voltage balancing control. To eliminate the differences of three clustered voltages, a new clustered voltage balancing control is proposed by regulating negative sequence modulation reference voltage in the dq frame. Its balancing mechanism is analyzed in detail and a simple implementation is presented as well. The effectiveness of the proposed control is verified by experimental results on a 400 V/15 kvar SCHB STATCOM.
Auteurs: Daorong Lu;Jiangfeng Wang;Jianhui Yao;Sen Wang;Jianxin Zhu;Haibing Hu;Li Zhang;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 10.-2017, volume: 64, issue:10, pages: 7623 - 7633
Editeur: IEEE
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» CMOS Low Noise Amplifier Topology Using Compact Wu Folded Active Inductor
Résumé:
This work presents a topology proposal of a 0.35um CMOS cascode low noise amplifier using an active inductor. The inductance required to output of cascode pair is synthesized by an active inductor in Compact Wu Folded configuration. The LNA presents a gain of 12.04 dB with a noise figure of 4.78 dB at 1.8 GHz. The layout is presented occupying an active area of 0.165 mm2. The results are satisfactory, validating a compact design and demonstrating the technical feasibility of this topology in the band of interest.
Auteurs: Eduardo Vicente Valdes Cambero;Rodrigo Reina Munoz;Ivan Roberto Santana Casella;Alfeu Sguarezi Filho;Humberto Xavier de Araujo;Carlos Eduardo Capovilla;
Apparue dans: IEEE Latin America Transactions
Date publication: 10.-2017, volume: 15, issue:10, pages: 1827 - 1833
Editeur: IEEE
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» CMOS Ultralow Power Brain Signal Acquisition Front-Ends: Design and Human Testing
Résumé:
Two brain signal acquisition (BSA) front-ends incorporating two CMOS ultralow power, low-noise amplifier arrays and serializers operating in mosfet weak inversion region are presented. To boost the amplifier's gain for a given current budget, cross-coupled-pair active load topology is used in the first stages of these two amplifiers. These two BSA front-ends are fabricated in 130 and 180 nm CMOS processes, occupying 5.45 mm $^{2}$ and 0.352 mm $^{2}$ of die areas, respectively (excluding pad rings). The CMOS 130-nm amplifier array is comprised of 64 elements, where each amplifier element consumes 0.216 $\mu$ W from 0.4 V supply, has input-referred noise voltage (IRNoise) of 2.19 $\mu$V$_{\text{RMS}}$ corresponding to a power efficiency factor (PEF) of 11.7, and occupies 0.044 mm $^{2}$ of die area. The CMOS 180 nm amplifier array employs 4 elements, where each element consumes 0.69 $\mu$ W from 0.6 V supply with IRNoise of 2.3 $\mu$ V$_{\text{RMS}}$ (corresponding to a PEF of 31.3) and 0.051 mm$^{2}$ of die area. Noninvasive electroencephalographic and invasive electrocorticographic signals were recorded real time directly on able-bodied human subjects, showing feasibility of using these analog front-ends for futur- fully implantable BSA and brain– computer interface systems.
Auteurs: Alireza Karimi-Bidhendi;Omid Malekzadeh-Arasteh;Mao-Cheng Lee;Colin M. McCrimmon;Po T. Wang;Akshay Mahajan;Charles Yu Liu;Zoran Nenadic;An H. Do;Payam Heydari;
Apparue dans: IEEE Transactions on Biomedical Circuits and Systems
Date publication: 10.-2017, volume: 11, issue:5, pages: 1111 - 1122
Editeur: IEEE
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» Co-Design of Controller and Communication Topology for Vehicular Platooning
Résumé:
Small inter-vehicle distances can increase traffic throughput on highways. Human drivers are not able to drive safely under such conditions. To this aim, cooperative adaptive cruise control (CACC) systems have been developed, which require vehicles to communicate with each other through a wireless communication network. By communicating control-relevant information, the vehicles equipped with the CACC system are able to react more quickly to disturbances caused by preceding vehicles and, therefore, are able to maintain the desired (small) inter-vehicle distance while avoiding string instability. String stability relates to the propagation of the effect of disturbance on system states over the vehicle string. Commonly used approaches to design controllers yielding string stability, involve an iterative process requiring an a priori designed controller with a priori defined communication topology. The main contribution of this paper is to propose a synthesis strategy for both local controllers and the communication structure, while guaranteeing string stability for infinite-length vehicular strings. The obtained results are illustrated by model-based case studies.
Auteurs: Amir Firooznia;Jeroen Ploeg;Nathan van de Wouw;Hans Zwart;
Apparue dans: IEEE Transactions on Intelligent Transportation Systems
Date publication: 10.-2017, volume: 18, issue:10, pages: 2728 - 2739
Editeur: IEEE
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» Coastal Sea-Level Measurements Based on GNSS-R Phase Altimetry: A Case Study at the Onsala Space Observatory, Sweden
Résumé:
The characterization of global mean sea level is important to predict floods and to quantify water resources for human use and irrigation, especially in coastal regions. Recently, the application of global navigation satellite system reflectometry (GNSS-R) for water level monitoring has been successfully demonstrated. This paper focuses on the retrieval of sea surface height within a field experiment that was conducted at the Onsala Space Observatory (OSO) using the phase-based altimetry method. A continuous phase tracking algorithm, which relies on the GNSS amplitude and phase observations is proposed and works even under rough sea conditions at OSO’s coast. Factors impacting the phase-based altimetry model, i.e., atmospheric propagation effects of the GNSS signals and influence of the GNSS-R observation instrument, are discussed. The relationship between the yield of coherent GNSS-R compared to the overall recorded events and the wind speed is investigated in detail. Ground-based sea-level measurements from June 10 to July 3, 2015 demonstrate that altimetric information about the reflecting water surface can be obtained with a root mean square error of 4.37 cm with respect to a reference tide gauge (TG) data set. The sea surface changes, derived from our field experiment and the reference TG, are highly correlated with a correlation coefficient of 0.93. The altimetric information can be retrieved even when the sea surface is very rough, corresponding to wind speeds up to 13 m/s. Moreover, the use of inexpensive conventional GNSS antennas shows that the system is useful for future large-scale sea level monitoring applications including numerous low-cost coastal ground stations.
Auteurs: Wei Liu;Jamila Beckheinrich;Maximilian Semmling;Markus Ramatschi;Sibylle Vey;Jens Wickert;Thomas Hobiger;Rüdiger Haas;
Apparue dans: IEEE Transactions on Geoscience and Remote Sensing
Date publication: 10.-2017, volume: 55, issue:10, pages: 5625 - 5636
Editeur: IEEE
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» Code-Shifted Differential Chaos Shift Keying With Code Index Modulation for High Data Rate Transmission
Résumé:
In the general code-shifted differential chaos shift keying (GCS-DCSK) system, multiple bit-streams are simultaneously carried by CS-DCSK signal using Walsh codes. However, its data rate is limited by the available Walsh codes in the Walsh code matrix due to orthogonality constraint of GCS-DCSK signal. In this paper, we propose a new GCS-DCSK scheme with code index modulation (CIM-CS-DCSK), which can achieve higher spectrum efficiency using code index modulation to carry additional bits. In the proposed scheme, the reference chaotic signal is the same as that of GCS-DCSK, and the multiple information bearing signals are simultaneously modulated by the information symbols and the selected Walsh codes with specific indices, which are determined by an integer sequence mapped from information symbols via the natural numbers to $k$ -combinations mapping method. We derive bit error rate of the proposed scheme over the additive white Gaussian noise channel. The numerical results not only verify our analysis but also show the advantage of the proposed scheme over GCS-DCSK. Through analyzing and comparing the numbers of carried bits per transmitted symbol of CIM-CS-DCSK and GCS-DCSK, it is shown that the proposed scheme can obtain higher data rate than GCS-DCSK with the same resource constraints.
Auteurs: Weikai Xu;Tingting Huang;Lin Wang;
Apparue dans: IEEE Transactions on Communications
Date publication: 10.-2017, volume: 65, issue:10, pages: 4285 - 4294
Editeur: IEEE
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» Coding for Improved Throughput Performance in Network Switches
Résumé:
Network switches and routers need to serve packet writes and reads at rates that challenge the most advanced memory technologies. As a result, scaling the switching rates is commonly done by parallelizing the packet I/Os using multiple memory units. For improved read rates, packets can be coded upon write, thus giving more flexibility at read time to achieve higher utilization of the memory units. This paper presents a detailed study of coded network switches, and in particular, how to design them to maximize the throughput advantages over standard uncoded switches. Toward that objective, the paper contributes a variety of algorithmic and analytical tools to improve and evaluate the throughput performance. The most interesting finding of this paper is that the placement of packets in the switch memory is the key to both high performance and algorithmic efficiency. One particular placement policy we call “design placement” is shown to enjoy the best combination of throughput performance and implementation feasibility.
Auteurs: Rami Cohen;Yuval Cassuto;
Apparue dans: IEEE/ACM Transactions on Networking
Date publication: 10.-2017, volume: 25, issue:5, pages: 2802 - 2814
Editeur: IEEE
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» Coding for Interactive Communication Correcting Insertions and Deletions
Résumé:
We consider the question of interactive communication, in which two remote parties perform a computation, while their communication channel is (adversarially) noisy. We extend here the discussion into a more general and stronger class of noise, namely, we allow the channel to perform insertions and deletions of symbols. These types of errors may bring the parties “out of sync,” so that there is no consensus regarding the current round of the protocol. In this more general noise model, we obtain the first interactive coding scheme that has a constant rate and tolerates noise rates of up to $1/18- \varepsilon $ . To this end, we develop a novel primitive we name edit-distance tree code. The edit-distance tree code is carefully designed to replace the Hamming distance constraints in Schulman’s tree codes (IEEE Trans. Inf. Theory, 1996), with a stronger edit-distance requirement.
Auteurs: Mark Braverman;Ran Gelles;Jieming Mao;Rafail Ostrovsky;
Apparue dans: IEEE Transactions on Information Theory
Date publication: 10.-2017, volume: 63, issue:10, pages: 6256 - 6270
Editeur: IEEE
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» Coding for the Large-Alphabet Adversarial Channel
Résumé:
We consider the problem of encoding an i.i.d. source into a set of symbols or messages that may be altered by an adversary while en route to the decoder. We focus in particular on the regime in which the number of messages is fixed while the blocklength of the source and the size of each message tend to infinity. For this fixed-blocklength, “large alphabet” channel, we show that combining an optimal rate-distortion code with an optimal error-correction code yields an optimal overall code for Gaussian sources with quadratic distortion and binary uniform sources with Hamming distortion but that it can be suboptimal by an arbitrarily large factor in general. We also consider the scenario in which the distortion constraint that the decoder must satisfy depends on the number of errors that occur. We show that the problem can be reduced operationally to one with erasures instead of errors in two special cases: one involving lossless reproduction of functions of the source and one in which the encoder and decoder share common randomness.
Auteurs: Ebad Ahmed;Aaron B. Wagner;
Apparue dans: IEEE Transactions on Information Theory
Date publication: 10.-2017, volume: 63, issue:10, pages: 6347 - 6363
Editeur: IEEE
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» Coding, Multicast, and Cooperation for Cache- Enabled Heterogeneous Small Cell Networks
Résumé:
Caching at the wireless edge is a promising approach to dealing with massive content delivery in heterogeneous wireless networks, which have high demands on backhaul. In this paper, a typical cache-enabled small cell network under heterogeneous file and network settings is considered using maximum distance separable (MDS) codes for content restructuring. Unlike those in the literature considering online settings with the assumption of perfect user request information, we estimate the joint user requests using the file popularity information and aim to minimize the long-term average backhaul load for fetching content from external storage subject to the overall cache capacity constraint by optimizing the content placement in all the cells jointly. Both multicast-aware caching and cooperative caching schemes with optimal content placement are proposed. In order to combine the advantages of multicast content delivery and cooperative content sharing, a compound caching technique, which is referred to as multicast-aware cooperative caching, is then developed. For this technique, a greedy approach and a multicast-aware in-cluster cooperative approach are proposed for the small-scale networks and large-scale networks, respectively. Mathematical analysis and simulation results are presented to illustrate the advantages of MDS codes, multicast, and cooperation in terms of reducing the backhaul requirements for cache-enabled small cell networks.
Auteurs: Jialing Liao;Kai-Kit Wong;Yangyang Zhang;Zhongbin Zheng;Kun Yang;
Apparue dans: IEEE Transactions on Wireless Communications
Date publication: 10.-2017, volume: 16, issue:10, pages: 6838 - 6853
Editeur: IEEE
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» Coherence in Multielement-Phased Vertical-Cavity Surface-Emitting Laser Arrays Using Resonance Tuning
Résumé:
We show that optical coupling can be achieved reproducibly and with high yield by resonance tuning the elements of substrate-emitting and top-emitting vertical-cavity surface-emitting laser arrays. The resonance tuning is enabled by electrical isolation of the lasing elements in the array, which in this paper is done by post fabrication processing. Prior to electrical isolation, the laser arrays exhibit incoherent optical properties. Using resonance tuning, both in-phase and out-of-phase coherent modes are observed.
Auteurs: Bradley J. Thompson;Zihe Gao;Stewart T. M. Fryslie;Matthew T. Johnson;Dominic F. Siriani;Kent D. Choquette;
Apparue dans: IEEE Photonics Journal
Date publication: 10.-2017, volume: 9, issue:5, pages: 1 - 8
Editeur: IEEE
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» Coherent Summation of Radiation From Four-Channel Shock-Excited RF Source Operating at 4 GHz and a Repetition Rate of 1000 Hz
Résumé:
Testing results of a generator based on the parallel gyromagnetic nonlinear transmission lines with saturated ferrite are presented. Practically identical and stable RF-modulated high-voltage nanosecond pulses were shaped in each of the four channels. The pulse amplitude reaches −175 kV at a modulation depth of RF oscillations to 50% and an effective frequency ~4 GHz. Power in the packet operation mode with a 1-s packet duration at pulse repetition frequencies up to 1000 Hz (in packet) was supplied by a solid-state driver. The electric field strength achieved 250 kV/m at a distance of 3 m from antennas.
Auteurs: Marat R. Ul’maskulov;Sergei A. Shunailov;Konstantin A. Sharypov;Michael I. Yalandin;Valery G. Shpak;Maxim S. Pedos;Sergei N. Rukin;
Apparue dans: IEEE Transactions on Plasma Science
Date publication: 10.-2017, volume: 45, issue:10, pages: 2623 - 2628
Editeur: IEEE
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» Coiling Size Dependence of Group Delay Spread in Coupled Multicore Fibers Without Intentional Twisting
Résumé:
Coiling size dependence of group delay spread (GDS) in coupled multicore fibers (MCFs) without intentional twisting is investigated by using a coupled-wave theory. It is shown that the GDS does not simply decrease with increasing bending radius and the optimum coiling size to decrease GDS depends on a core-to-core distance of MCFs. It is also found that a coupled MCF with a trench-assisted profile is suitable for realizing lower GDS with higher spatial density compared with a coupled MCF with a step-index profile.
Auteurs: Kunimasa Saitoh;Takeshi Fujisawa;Takanori Sato;
Apparue dans: Journal of Lightwave Technology
Date publication: 10.-2017, volume: 35, issue:20, pages: 4559 - 4566
Editeur: IEEE
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» Collaborative Multi-Tier Caching in Heterogeneous Networks: Modeling, Analysis, and Design
Résumé:
To deal with the explosive growth in multimedia service requests in mobile networks, caching contents at the cells (base stations) is regarded as an effective emerging technique to reduce the duplicated transmissions of content downloads, while heterogeneous networks (HetNets) are regarded as an effective technique to increase the network capacity. Yet, the combination of content caching and HetNets for future networks (i.e., 5G) is still not well explored. In this paper, we propose an efficient collaborative multi-tier caching framework in Het-Nets. In particular, based on patterns of user requests, link capacities, heterogenous cache sizes, and the derived system topology, we focus on exploring the maximum capacity of the network infrastructure so as to offload the network traffic and support users’ content requests locally. Due to the NP-hardness of the complex multi-tier caching problem, we approximately decompose it into some subproblems that focus on the caching cooperation at different tiers by utilizing the derived system topology. Our proposed framework is low-complexity and distributed, and can be used for practical engineering implementation. Trace-based simulation results demonstrate the effectiveness of the proposed framework.
Auteurs: Xiuhua Li;Xiaofei Wang;Keqiu Li;Zhu Han;Victor C. M. Leung;
Apparue dans: IEEE Transactions on Wireless Communications
Date publication: 10.-2017, volume: 16, issue:10, pages: 6926 - 6939
Editeur: IEEE
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» Collaborators & Friends: The General Meeting Brings Us Together [Leader's Corner]
Résumé:
Presents highlights of the PES society 2017 General Meeting.
Auteurs: Jessica Bian;
Apparue dans: IEEE Power and Energy Magazine
Date publication: 10.-2017, volume: 15, issue:5, pages: 10 - 10
Editeur: IEEE
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» Collective Hyping Detection System for Identifying Online Spam Activities
Résumé:
Although existing antispam strategies detect traditional spam activities effectively, evolving spam schemes can successfully cheat conventional testing by buying the comments that are written by genuine users and sold by specific web markets. Such spam activities turn into a kind of advertising campaign among business owners to maintain their rank in top positions. This article proposes a new collaborative marketing hyping detection solution that aims to identify spam comments generated by the Spam Reviewer Cloud and detect products that adopt an evolving spam strategy for promotion. The authors propose an unsupervised learning model that combines heterogeneous product review networks in an attempt to discover collective hyping activities. Their experiments validate the existence of the collaborative marketing hyping activities on a real-life ecommerce platform and demonstrate that their model can effectively and accurately identify these advanced spam activities.
Auteurs: Qinzhe Zhang;Jia Wu;Peng Zhang;Guodong Long;Chengqi Zhang;
Apparue dans: IEEE Intelligent Systems
Date publication: 10.-2017, volume: 32, issue:5, pages: 53 - 63
Editeur: IEEE
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» Colloidal CdSe Quantum Dots and PQT-12-Based Low-Temperature Self-Powered Hybrid Photodetector
Résumé:
In this letter, a novel dual junction self-powered hybrid photodetector is proposed using colloidal CdSe quantum dots (QDs) as an active layer (~50-nm thickness), and PQT-12 polymer as filter layer subsequently deposited on an ITO-coated glass substrate by the spin coating method. The colloidal CdSe QDs are deposited on the PQT-12 film at 80 °C, which is much smaller than the growth temperature (usually >300 °C) of the inorganic layer of other reported hybrid self-powered detectors. The Au metal dots are deposited on the CdSe QD layer for anode electrodes while the ITO acts as the cathode electrode of the device. Two asymmetric depletion widths formed at PQT-12/CdSe and Au/CdSe junctions at two sides of the active layer controls the operation of the proposed detector. The photodetector shows band-pass response over the visible spectrum with a sharp cutoff for higher wavelengths at ~610 nm. The maximum responsivity and detectivity of the self-powered photodetector are achieved to be ~3.3 mA/W and $5.4\times 10^{9}$ cmHz $^{1/2}\text{W}^{-1}$ , respectively, at a wavelength of ~420 nm under the optical power density of $\sim 130\mu \text{W}$ /cm2. The rise time and fall time of the device are found to be ~12.01 and ~15.32 ms, respectively.
Auteurs: Hemant Kumar;Yogesh Kumar;Gopal Rawat;Chandan Kumar;Bratindranath Mukherjee;Bhola N. Pal;Satyabrata Jit;
Apparue dans: IEEE Photonics Technology Letters
Date publication: 10.-2017, volume: 29, issue:20, pages: 1715 - 1718
Editeur: IEEE
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» Combination of SHE- and SHM-PWM Techniques for VSI DC-Link Current Harmonics Control in Railway Applications
Résumé:
The paper presents an innovative concept of applying a combination of well-known selective harmonic elimination (SHE) and selective harmonics mitigation (SHM) methods to shape a spectrum of catenary current harmonics, generated by a traction drive system equipped with a voltage source inverter. Application of this method allows for reducing distorting influence of a modern rolling stock supplied by a 3 kV dc catenary on the railway signaling, command, and control systems. The efficiency of the proposed method is independent of synchronization of a vehicle's inverters and of load balance of traction motors, which makes it more reliable than as it is proposed in the literature. Results of computer simulations were presented and compared with laboratory measurements. The obtained dc-link current spectrum using the proposed SHE/SHM method was compared with spectra received using synchronized and unsynchronized sinusoidal pulse-width modulations (SPWMs). Based on the conducted tests, it was shown that the proposed method of control, which was implemented in a laboratory drive system, is effective in reducing dc side current harmonics in a frequency range of 1300-3100 Hz, which is used by track circuits on railway lines, e.g., in Poland. The technique proposed by the authors allows taking into account any restrictions arising from the technical nature of low-frequency traction drives.
Auteurs: Marcin Steczek;Piotr Chudzik;Adam Szeląg;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 10.-2017, volume: 64, issue:10, pages: 7666 - 7678
Editeur: IEEE
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» Combined Pulse-Echo Ultrasound and Multispectral Optoacoustic Tomography With a Multi-Segment Detector Array
Résumé:
The high complementarity of ultrasonography and optoacoustic tomography has prompted the development of combined approaches that utilize the same transducer array for detecting both optoacoustic and pulse-echo ultrasound responses from tissues. Yet, due to the fundamentally different physical contrast and image formation mechanisms, the development of detection technology optimally suited for image acquisition in both modalities remains a major challenge. Herein, we introduce a multi-segment detector array approach incorporating array segments of linear and concave geometry to optimally support both ultrasound and optoacoustic image acquisition. The various image rendering strategies are tested and optimized in numerical simulations and calibrated tissue-mimicking phantom experiments. We subsequently demonstrate real-time hybrid optoacoustic ultrasound image acquisition in a healthy volunteer. The new approach enables the acquisition of high-quality anatomical data by both modalities complemented by functional information on blood oxygenation status provided by the multispectral optoacoustic tomography.
Auteurs: Elena Merčep;Xosé Luís Deán-Ben;Daniel Razansky;
Apparue dans: IEEE Transactions on Medical Imaging
Date publication: 10.-2017, volume: 36, issue:10, pages: 2129 - 2137
Editeur: IEEE
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» Combined Speed and Steering Control in High-Speed Autonomous Ground Vehicles for Obstacle Avoidance Using Model Predictive Control
Résumé:
This paper presents a model predictive control-based obstacle avoidance algorithm for autonomous ground vehicles at high speed in unstructured environments. The novelty of the algorithm is its capability to control the vehicle to avoid obstacles at high speed taking into account dynamical safety constraints through a simultaneous optimization of reference speed and steering angle without a priori knowledge about the environment and without a reference trajectory to follow. Previous work in this specific context optimized only the steering command. In this paper, obstacles are detected using a planar light detection and ranging sensor. A multi-phase optimal control problem is then formulated to simultaneously optimize the reference speed and steering angle within the detection range. Vehicle acceleration capability as a function of speed, as well as stability and handling concerns such as preventing wheel lift-off, are included as constraints in the optimization problem, whereas the cost function is formulated to navigate the vehicle as quickly as possible with smooth control commands. Simulation results show that the proposed algorithm is capable of safely exploiting the dynamic limits of the vehicle while navigating the vehicle through sensed obstacles of different sizes and numbers. It is also shown that the proposed variable speed formulation can significantly improve performance by allowing navigation of obstacle fields that would otherwise not be cleared with steering control alone.
Auteurs: Jiechao Liu;Paramsothy Jayakumar;Jeffrey L. Stein;Tulga Ersal;
Apparue dans: IEEE Transactions on Vehicular Technology
Date publication: 10.-2017, volume: 66, issue:10, pages: 8746 - 8763
Editeur: IEEE
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» Combining Software-Defined and Delay-Tolerant Approaches in Last-Mile Tactical Edge Networking
Résumé:
Network-centric warfare is a no-way-back trend in modern military operations. The application of this concept ranges from upper-level decision making echelons to troop guidance on the battlefield, and many studies have been carried out in this area. However, most of these are concerned with either the higher-level strategic networks, that is, the networks linking the higher echelons with abundant resources, satellite communications, or even a whole network infrastructure, or high-end TEN, representing resource-rich troops in the field, with military aircraft, battleships, or ground vehicles equipped with powerful wireless communication devices and (almost) unrestricted energy resources for communication. However, these studies fail to take into account the "last-mile TEN," which comprises resource constrained communication devices carried by troopers, equipping sensor nodes deployed in the field or small unmanned aerial vehicles. In an attempt to fill this gap in the studies on battlefield networking, this article seeks to combine software-defined and delay-tolerant approaches to support the diverse range of strict requirements for applications in the last-mile TEN.
Auteurs: Iulisloi Zacarias;Luciano P. Gaspary;Andersonn Kohl;Ricardo Q. A. Fernandes;Jorgito M. Stocchero;Edison P. de Freitas;
Apparue dans: IEEE Communications Magazine
Date publication: 10.-2017, volume: 55, issue:10, pages: 22 - 29
Editeur: IEEE
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» Command and Control for Multifunction Phased Array Radar
Résumé:
We discuss the challenge of managing the Multifunction Phased Array Radar (MPAR) timeline to satisfy the requirements of its multiple missions, with a particular focus on weather surveillance. This command and control (C2) function partitions the available scan time among these missions, exploits opportunities to service multiple missions simultaneously, and utilizes techniques for increasing scan rate where feasible. After reviewing the candidate MPAR architectures and relevant previous research, we describe a specific C2 framework that is consistent with a demonstrated active array architecture using overlapped subarrays to realize multiple, concurrent receive beams. Analysis of recently articulated requirements for near-airport and national-scale aircraft surveillance indicates that with this architecture, 40–60% of the MPAR scan timeline would be available for the high-fidelity weather observations currently provided by the Weather Service Radar (WSR-88D) network. We show that an appropriate use of subarray generated concurrent receive beams, in concert with previously documented, complementary techniques to increase the weather scan rate, could enable MPAR to perform full weather volume scans at a rate of 1 per minute. Published observing system simulation experiments, human-in-the-loop studies and radar-data assimilation experiments indicate that high-quality weather radar observations at this rate may significantly improve the lead time and reliability of severe weather warnings relative to current observation capabilities.
Auteurs: Mark E. Weber;John Y. N. Cho;Henry G. Thomas;
Apparue dans: IEEE Transactions on Geoscience and Remote Sensing
Date publication: 10.-2017, volume: 55, issue:10, pages: 5899 - 5912
Editeur: IEEE
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» Comments on “Tracking Control of Robotic Manipulators With Uncertain Kinematics and Dynamics”
Résumé:
This letter considers the paper entitled “Tracking Control of Robotic Manipulators With Uncertain Kinematics and Dynamics” by B. Xiao, S. Yin, and O. Kaynak [IEEE Trans. Ind. Electron., vol. 63, no. 10, pp. 6439–6449, Oct. 2016], where the authors meant to provide an effective control for finite-time tracking of robot manipulators with both kinematic and dynamic uncertainties. This letter points out several flaws leading to the ineffectiveness of the main result in the paper. A correction is proposed.
Auteurs: Yuxin Su;Chunhong Zheng;Paolo Mercorelli;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 10.-2017, volume: 64, issue:10, pages: 8187 - 8189
Editeur: IEEE
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» Comments on “Interference-Based Capacity Analysis of Vehicular Ad Hoc Networks”
Résumé:
A new effective interference-based capacity model was proposed for vehicular ad hoc network safety message broadcast scenario in M. Ni et al. (Commun. Lett., vol. 19, no. 4, pp. 621–624, Apr. 2015). This letter is a reconsideration and extension of the model in Ni et al.. First, we point out that the analysis in Ni et al. is incomplete and show a new derivation of the node transmission probability and the SIR distribution accounting for the impact of asynchronous timing of hidden terminals and all possible interference occurrence cases. Second, the analysis is extended to the derivation of other important quality of service metrics, such as packet reception probability, packet reception ratio, and transmission capacity. The proposed analysis is cross validated by MATLAB, PYTHON, and NS2 simulations.
Auteurs: Xiaomin Ma;Hualin Lu;Jing Zhao;Yanbin Wang;Jingyu Li;Minming Ni;
Apparue dans: IEEE Communications Letters
Date publication: 10.-2017, volume: 21, issue:10, pages: 2322 - 2325
Editeur: IEEE
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» Communication With Imperfectly Shared Randomness
Résumé:
Communication complexity investigates the amount of communication needed for two or more players to determine some joint function of their private inputs. For many interesting functions, the communication complexity can be much smaller than basic information theoretic measures associated with the players’ inputs such as the input length, the entropy, or even the conditional entropy. Communication complexity of many functions reduces further when the players share randomness. Classical works studied the communication complexity of functions when the interacting players share randomness perfectly, i.e., they get identical copies of randomness from a common source. This paper considers the variant of this question when the players share randomness imperfectly, i.e., when they get noisy copies of the randomness produced by some common source. Our main result shows that any function that can be computed by a $k$ -bit protocol in the perfect sharing model has a $2^{k}$ -bit protocol in the setting of imperfectly shared randomness and such an exponential growth is necessary. Our upper bound relies on ideas from locality sensitive hashing, while lower bounds rely on hypercontractivity and a new invariance principle tailored for communication protocols.
Auteurs: Clément L. Canonne;Venkatesan Guruswami;Raghu Meka;Madhu Sudan;
Apparue dans: IEEE Transactions on Information Theory
Date publication: 10.-2017, volume: 63, issue:10, pages: 6799 - 6818
Editeur: IEEE
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» Compact and High-Gain UHF/UWB RFID Reader Antenna
Résumé:
A linearly polarized, dual-port, and dual-band radio frequency identification reader antenna is designed to simultaneously operate at ultrahigh frequency (UHF) and ultra-wideband bands for positioning systems. A hybrid design using patch and slot structures within a shared radiating aperture is proposed and demonstrated to achieve a high gain and wideband operation with a limited profile. The size of the total antenna is 200 mm $\times200$ mm $\times10$ mm. The measured impedance bandwidth of the UHF antenna ranges from 0.890 to 0.907 GHz with a minimum antenna gain of 9 dBi. The measured impedance bandwidth of the ultra-wideband antenna can cover the frequency band from 3 to 4.99 GHz with a minimum antenna gain of 9 dBi. The antenna gains near two WLAN bands are less than −15 dBi at 2.45 GHz and −5 dBi at 5.8 GHz, respectively. The mutual coupling between the two ports is less than −30 dB over the two bands.
Auteurs: Jun Zhang;Zhongxiang Shen;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 10.-2017, volume: 65, issue:10, pages: 5002 - 5010
Editeur: IEEE
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» Compact and Low-Cost Optical Fiber Respiratory Monitoring Sensor Based on Intensity Interrogation
Résumé:
In this paper, a plastic optical fiber sensor for respiratory monitoring purposes is presented. The sensor was integrated into a small, robust, and flexible package to be attached directly on a wide variety of positions on the upper body to monitor the motion induced by breathing. The sensor's operating principle is based on the variation in the intensity of the optical coupling intensity ratio between an input and a set of aligned output optical fibers. The system is demonstrated to be able to track the time-varying breathing signal when the sensor is placed at four different positions of the torso (including diaphragmatic and upper costal). The accuracy of the device is confirmed by a simultaneous comparison of the results with a commercial respiratory monitoring device. Measurement of breathing rate on four different healthy subjects showed excellent agreement with the measurement from the commercial respiratory monitoring device. The proposed fiber optic respiration sensor provides the advantages of being relatively low cost, compact, and simple in construction compared to the conventional existing respiration sensors.
Auteurs: Wern Kam;Waleed Soliman Mohammed;Gabriel Leen;Mary O'Keeffe;Kieran O'Sullivan;Sinead O'Keeffe;Elfed Lewis;
Apparue dans: Journal of Lightwave Technology
Date publication: 10.-2017, volume: 35, issue:20, pages: 4567 - 4573
Editeur: IEEE
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» Compact Differential Wideband Bandpass Filters Based on Half-Wavelength Lines
Résumé:
A compact differential wideband bandpass filter is proposed based on three half-wavelength transmission lines. The main advantages of small size and simple configuration are achieved. The improved design with two cascaded quarter-wavelength coupled lines can further improve the bandwidth of common-mode (CM) suppression and frequency selectivity. Two prototypes centered at 1.8 GHz with the size of $0.07\lambda _{g}^{2}(\lambda _{g}$ is the guided wavelength at the center frequency $f_{0}$ ) and $0.056\lambda _{g}^{2}$ are designed, fabricated, and measured. The measured results of Design I (Design II) exhibit the minimum insertion loss of 0.27 dB (0.6 dB), 3-dB fractional bandwidth of 57.8% (52%), and the bandwidth of 20-dB CM suppression of $0.67 f_{0}~(4.1 f_{0})$ .
Auteurs: Jun Qiang;Jin Shi;Qinghua Cao;Zhidan Shen;
Apparue dans: IEEE Microwave and Wireless Components Letters
Date publication: 10.-2017, volume: 27, issue:10, pages: 906 - 908
Editeur: IEEE
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» Compact On-Chip Bandpass Filter With Improved In-Band Flatness and Stopband Attenuation in 0.13- $\mu \text{m}$ (Bi)-CMOS Technology
Résumé:
In this letter, an on-chip miniaturized bandpass filter (BPF) is presented, which is based on a grounded center-tapped ring resonator (CTRR) with shunt capacitive loading. To analyze the principle of this design, a simple but effective equivalent circuit model is provided. Using this model, it is easy to show that the CTRR-based approach has a potential to generate two transmission poles within the passband. Compared with the conventional single-pole-based approach, this dual-pole design not only possesses a flexibility of controlling the passband width, but also has better flatness of insertion loss in the passband. In addition, this approach is able to significantly improve the stopband performance. To further demonstrate the feasibility of this approach in practice, the structure is implemented and fabricated in a commercial 0.13- $\mu \text{m}$ (Bi)-CMOS SiGe technology. The measured results show that the BPF has a center frequency at 33 GHz with a bandwidth of 42.4%. The minimum insertion loss is 2.6 dB, while the stopband rejection is maintained to be better than 20 dB beyond 58 GHz. The chip, excluding the pads, is very compact at only 0.03 mm2 ( $0.11\times0.28$ mm $^{{2}}{)}$ .
Auteurs: Yang Yang;Hang Liu;Zhang Ju Hou;Xi Zhu;Eryk Dutkiewicz;Quan Xue;
Apparue dans: IEEE Electron Device Letters
Date publication: 10.-2017, volume: 38, issue:10, pages: 1359 - 1362
Editeur: IEEE
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» Compact Polygonal Active-Mirror Laser With Composite Nd:YAG/YAG Gain Medium
Résumé:
A compact polygonal active-mirror (PAM) laser with composite Nd: YAG/YAG multithin-disk gain medium has been demonstrated with total internal reflection scheme. Five Nd:YAG thin disks with a neodymium concentration of 0.7 at.% and thickness of ∼0.2 mm were bonded to five different surfaces of a hexagonal YAG substrate. With no heat sink, output power of 1.03 W at 1064 nm and beam quality of M2 = 1.21 was obtained from a short-cavity oscillator based on the PAM architecture, under an absorption pump power of 2.30 W, with a slope efficiency and optical to optical efficiency of 55.8% and 44.8%, respectively.
Auteurs: Yanzhong Chen;Ye Lang;Lifen Liao;Zhongwei Fan;Jianguo He;Guangyan Guo;Weiran Lin;Yunfeng Ma;Hongbo Zhang;Jian Zhang;
Apparue dans: IEEE Photonics Journal
Date publication: 10.-2017, volume: 9, issue:5, pages: 1 - 8
Editeur: IEEE
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» Compact Wideband Dual Loop Coupler With High Power Handling Capability for Radar Applications
Résumé:
Couplers are widely used in microwave subsystems, especially for radar applications. They are used to extract a directive sample of the output signal of an RF source. Typically, a coupler consists of a main arm and a secondary arm connected via coupling section. For couplers used in radar applications, power handling is a limiting factor for designers. In addition, the coupling value must be kept a flat with a high directivity over the operating bandwidth of the coupler. In this letter, we provide designs for two compact loop couplers, operating in the frequency range of 1–2 GHz and 2–4 GHz. These designs have flat coupling of −60 dB and achieve matching below −22 dB.
Auteurs: Shoukry I. Shams;Mahmoud Elsaadany;Gada Saad;Ahmed A. Kishk;
Apparue dans: IEEE Microwave and Wireless Components Letters
Date publication: 10.-2017, volume: 27, issue:10, pages: 900 - 902
Editeur: IEEE
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» Compact, Frequency-Reconfigurable Filtenna With Sharply Defined Wideband and Continuously Tunable Narrowband States
Résumé:
A compact, frequency-reconfigurable filtenna with sharp out-of-band rejection in both its wideband and continuously tunable narrowband states is presented. It is intended for use in cognitive radio applications. The wideband state is the sensing state and operationally covers 2.35–4.98 GHz. The narrowband states are intended to cover communications within the 3.05–4.39 GHz range, which completely covers the Worldwide Interoperability for Microwave Access (WiMAX) band and the satellite communications C-band. A p-i-n diode is employed to switch between these wide and narrowband operational states. Two varactor diodes are used to shift the operational frequencies continuously among the narrowband states. The filtenna consists of a funnel-shaped monopole augmented with a reconfigurable filter; it has a compact electrical size: $0.235\lambda _{\textrm {L}} \times 0.392\lambda _{\textrm {L}}$ , where the wavelength $\lambda _{\textrm {L}}$ corresponds to the lower bound of its operational frequencies. The measured reflection coefficients, radiation patterns, and realized gains for both operational states are in good agreement with their simulated values.
Auteurs: Ming-Chun Tang;Zheng Wen;Hao Wang;Mei Li;Richard W. Ziolkowski;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 10.-2017, volume: 65, issue:10, pages: 5026 - 5034
Editeur: IEEE
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» Comparative Analysis on Conducted CM EMI Emission of Motor Drives: WBG Versus Si Devices
Résumé:
Silicon carbide (SiC) MOSFETs and gallium nitride (GaN) high-electron mobility transistors are perceived as future replacements for Si IGBTs and MOSFETs in medium- and low-voltage drives due to their low conduction and switching losses. However, it is widely believed that the already significant conducted common-mode (CM) electromagnetic interference (EMI) emission of motor drives will be further exacerbated by the high-speed switching operation of these new devices. Hence, this paper investigates and quantifies the increase in the conducted CM EMI emission of a pulse width modulation inverter-based motor drive when SiC and GaN devices are adopted. Through an analytical approach, the results reveal that the influence of dv/dt on the conducted CM emission is generally limited. On the other hand, the influence of switching frequency is more significant. Lab tests are also conducted to verify the analysis.
Auteurs: Di Han;Silong Li;Yujiang Wu;Wooyoung Choi;Bulent Sarlioglu;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 10.-2017, volume: 64, issue:10, pages: 8353 - 8363
Editeur: IEEE
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» Comparative Study of the Biological Responses to Conventional Pulse and High-Frequency Monopolar Pulse Bursts
Résumé:
Given its nonthermal property and other advantages, irreversible electroporation (IRE) has quickly translated into clinical applications. An increasing number of clinical cases using IRE have also revealed crucial issues. The uneven distribution of the electric field caused by the heterogeneity of biological tissues has not been completely and effectively addressed to date. The use of high-frequency monopolar pulse bursts (HFMPBs) is expected to solve this problem. The high-frequency content of the HFMPB is used to ensure the uniform distribution of the electric field in the tissue. A temperature increase similar to that of the conventional pulse method does not cause thermal damage and results in a killing effect similar to that of the conventional technique. Meanwhile, the subpulse has a pulse duration of 1– $100~\mu \text{s}$ , which remains unexplored and may induce new cell responses. This paper analyzes the HFMPB based on the frequency domain and infers that the cell death pathways under this pulse induce necrosis and other processes, such as apoptosis. The phosphatidylserine externalization rate had a peak value at a different inner frequency of HFMPB when the electric field was 1 kV/cm for melanoma cells. This new type of pulse is expected to solve the problem of the uneven distribution of the electric field without altering the cell killing effect. If this effect is also verified in tissue ablation, these new types of pulses will promote the clinical application of IRE.
Auteurs: Chenguo Yao;Yajun Zhao;Yan Mi;Shoulong Dong;Yanpeng Lv;Hongmei Liu;Xiaoyu Wang;Liling Tang;
Apparue dans: IEEE Transactions on Plasma Science
Date publication: 10.-2017, volume: 45, issue:10, pages: 2629 - 2638
Editeur: IEEE
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» Comparison of Elevation Change Detection Methods From ICESat Altimetry Over the Greenland Ice Sheet
Résumé:
Estimation of the surface elevation change of the Greenland Ice Sheet (GrIS) is essential for understanding its response to recent and future climate change. Laser measurements from the NASA’s Ice, Cloud, and land Elevation Satellite (ICESat) created altimetric surveys of GrIS surface elevations over the 2003–2009 operational period of the mission. This paper compares four change detection methods using Release 634 ICESat laser altimetry data: repeat tracks (RTs), crossovers (XOs), overlapping footprints (OFPs), and triangulated irregular networks (TINs). All four methods begin with a consistently edited data set and yield estimates of volumetric loss of ice from the GrIS ranging from −193 to −269 km3/yr. Using a uniform approach for quantifying uncertainties, we find that volume change rates at the drainage system scale from the four methods can be reconciled within 1- $\sigma $ uncertainties in just 5 of 19 drainage systems. Ice-sheet-wide volume change estimates from the four methods cannot be reconciled within 1- $\sigma $ uncertainties. Our volume change estimates lie within the range of previously published estimates, highlighting that the choice of method plays a dominant role in the scatter of volume change estimates. We find that for much of the GrIS, the OFP and TIN methods yield the lowest volume change uncertainties because of their superior spatial distribution of elevation change rate estimates. However, the RT and XO methods offer inherent advantages, and the future work to combine the elevation change detection methods to produce better estimates is warranted.
Auteurs: Denis Felikson;Timothy J. Urban;Brian C. Gunter;Nadège Pie;Hamish D. Pritchard;Robert Harpold;Bob E. Schutz;
Apparue dans: IEEE Transactions on Geoscience and Remote Sensing
Date publication: 10.-2017, volume: 55, issue:10, pages: 5494 - 5505
Editeur: IEEE
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» Comparison of Fabrication Techniques for Flexible UHF RFID Tag Antennas [Wireless Corner]
Résumé:
The astonishing boom of radio-frequency identification (RFID) technology is stimulating plenty of new RFID-based industrial applications. Consequently, in the very near future, an almost unlimited number of RFID tags could be embedded into manufactured goods of various shapes, assets, and machineries to enable their communication abilities. As a result, prototyping techniques of RFID tags on flexible substrates are becoming more crucial. In this article, four different techniques suitable for prototyping flexible tags are briefly explained and tested from many points of view: ease of use, processing time, cost, tag sensitivity, radiation pattern, impedance, and robustness of the realized prototype. Characterization methods and experimental setups are presented, and two tag layouts, one commercial and one appositely designed, are used to compare the different techniques.
Auteurs: Riccardo Colella;Almudena Rivadeneyra;Alberto J. Palma;Luciano Tarricone;Luis Fermin Capitan-Vallvey;Luca Catarinucci;Jose F. Salmeron;
Apparue dans: IEEE Antennas and Propagation Magazine
Date publication: 10.-2017, volume: 59, issue:5, pages: 159 - 168
Editeur: IEEE
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» Comparison of High-Speed Electrical Motors for a Turbo Circulator Application
Résumé:
This paper presents an analysis of three different electrical machine topologies for a turbo circulator application. The electrical machines are designed to operate with 6 kW output power at 120 000 r/min. This paper demonstrates the design aspects of one solid rotor squirrel cage induction motor and two permanent magnet synchronous machines. The machines are compared using electromagnetic, thermal, and mechanical analyses. The benefits and disadvantages of each topology under study are discussed. For other high-speed applications presented, a comparative approach helps in selecting the suitable electrical machine topology by analyzing the performance criteria discussed. The prototype construction of one of the topologies is analyzed.
Auteurs: Nikita Uzhegov;Jan Barta;Jiri Kurfürst;Cestmir Ondrusek;Juha Pyrhönen;
Apparue dans: IEEE Transactions on Industry Applications
Date publication: 10.-2017, volume: 53, issue:5, pages: 4308 - 4317
Editeur: IEEE
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» Comparison of Two-Individual Current Control and Vector Space Decomposition Control for Dual Three-Phase PMSM
Résumé:
The relationship between the two-individual current control and the vector space decomposition (VSD) control for a dual three-phase permanent magnet synchronous machine (PMSM) is investigated in this paper. It is found that the VSD control is more flexible in controlling the fundamental current in $\alpha \beta $ subplane and the fifth, seventh current harmonics in $z_{1}z_{2}$ subplane with different proportional and integral (PI) gains, while the two-individual current control is comparable with the VSD control in having the same PI gains in the $\alpha \beta $ and $z_{1}z_{2}$ subplanes. It is also found that the two-individual current control may have potential instability issues due to the mutual coupling between the two sets of three-phase windings. If the mutual coupling between the two sets is weak to some extent, then the two-individual current control could have the same dynamic performance as the VSD control without the stability issues. Experiments are conducted on a prototype dual three-phase PMSM to validate the theoretical analysis.
Auteurs: Yashan Hu;Z. Q. Zhu;Milijana Odavic;
Apparue dans: IEEE Transactions on Industry Applications
Date publication: 10.-2017, volume: 53, issue:5, pages: 4483 - 4492
Editeur: IEEE
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» Compete or Collaborate: Architectures for Collaborative DASH Video Over Future Networks
Résumé:
Dynamic adaptive streaming over HTTP (DASH) clients compete with each other over one or more bottleneck links in a network, which results in fluctuations in TCP throughput and QoE, QoE unfairness among clients, and underutilization of the network capacity. We propose centralized and distributed architectures for collaboration between network service provider (NSP), video service provider (VSP), and users (DASH clients) to provide NSP-managed or VSP-managed DASH services over software-defined networks (SDN) with quality-of-service (QoS) reserved network slices. We show that QoS reservation alone is not sufficient to overcome QoE fluctuations per client and unfairness between heterogeneous video clients, and clients also need to employ TCP receive-window adaptation knowing their fair-share bitrate. To this effect, we propose two collaborative streaming service models to inform clients about their fair-share bitrates. We first present an NSP-managed service model with centralized collaboration between the NSP, VSP, and the users, where a traffic engineering manager at the NSP assigns a fair-share bitrate to each DASH client. We then present a VSP-managed service model with centralized or distributed collaboration architectures, where in the former the VSP determines the fair-share bitrate for each client over a reserved network slice and in the latter a group of DASH clients sharing a reserved network slice collaborate among themselves. In the novel distributed collaboration framework, collaboration groups are identified by the VSP, and clients within a group share critical parameters with each other so that each client can estimate its fair-share bitrate. Experimental results demonstrate that collaboration rather than competition between clients not only helps them achieve a smooth goodput near their fair-share bitrate, but also improves the total goodput over the reserved slice.
Auteurs: Kadir Tolga Bagci;Kemal Emrecan Sahin;A. Murat Tekalp;
Apparue dans: IEEE Transactions on Multimedia
Date publication: 10.-2017, volume: 19, issue:10, pages: 2152 - 2165
Editeur: IEEE
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» Complete Electrical Arc Hazard Classification System and Its Application
Résumé:
The standard for electrical safety in the workplace, National Fire Protection Association 70E, and relevant Occupational Safety and Health Act electrical safety standards evolved in the U.S. over the past 40 years to address the hazards of 60-Hz power that are faced primarily by electricians, linemen, and others performing facility and utility work. This leaves a substantial gap in the management of other types of electrical hazards including battery banks, dc power systems, capacitor banks, and solar power systems. Although many of these systems are fed by 50/60-Hz energy, we find substantial use of electrical energy, and the use of capacitors, inductors, batteries, solar, and radiofrequency (RF) power. The electrical hazards of these forms of electricity and their systems are different than for 50/60 Hz ac power. At the IEEE Electrical Safety Workshop in 2009, we presented a comprehensive approach to classifying the electrical shock hazards of all types of electricity, including various waveforms and various types of sources of electrical energy. That paper introduced a new comprehensive electrical shock hazard classification system that used a combination of voltage, shock current available, fault current available, power, energy, and waveform to classify all forms of electrical hazards with a focus on the shock hazard. That paper was based on research conducted over the past 100 years and on decades of experience. This paper continues the effort in understanding and managing all forms of injury from all forms of electricity with the introduction of a comprehensive approach to classifying all forms of injury from the electrical arc, including thermal, blast pressure, hearing, radiation, and shrapnel injury. The general term “arc” is divided into the arc, arc flash, and arc blast as a first subdivision of type of source of injury. Then, the parameters of voltage, short-circuit current, energy, waveform, gap distance, gap geom- try, enclosure geometry, and time are used to choose various approaches to analysis. Recent efforts to understand, model, and estimate injury for these types of systems are reviewed. Most of the focus to understand and predict injury for dc, capacitor, solar, and RF arc hazards has been only in the past 10 years. A comprehensive approach to analyzing all forms of injury from all forms of electrical arcs is presented.
Auteurs: Lloyd B. Gordon;Kyle D. Carr;Nicole Graham;
Apparue dans: IEEE Transactions on Industry Applications
Date publication: 10.-2017, volume: 53, issue:5, pages: 5078 - 5087
Editeur: IEEE
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» Completion Time Analysis of Wafer Lots in Single-Armed Cluster Tools With Parallel Processing Modules
Résumé:
We analyze the completion time of wafer lots in single-armed cluster tools with parallel processing modules (PMs) by considering the lot switching operation. To effectively assign wafer lots and dispatch overhead hoist transports (OHTs) to manufacturing tools, it is crucial to obtain the completion time of wafer lots. However, estimating the completion time is not straightforward, due to the concurrent processing of two consecutive wafer lots during lot switching operation, which often increases wafer sojourn times in PMs. In this paper, we derive closed-form expressions of the completion time of wafer lots in single-armed cluster tools with parallel PMs. We assume that the robot unloads wafers in the order of their loading sequence. We then experimentally show that the formulas derived can be used even when processing time variation exists or another robot task sequence, which is of first-in first-out (FIFO), is assumed.

Note to Practitioners—Due to the larger wafer size and circuit width reduction, cluster tools often perform the lot switching operation with each pair of consecutive wafer lots. In addition, since most tools are operated with parallel chambers, concurrent processing with two different wafer lots occurs frequently. Such transient periods in operating tools make it hard to estimate the completion time of wafer lots. In this paper, we derive closed-form expressions to obtain the completion time of wafer lots in single-armed cluster tools with parallel chambers. We further show that the formulas can be used with processing time variation or the FIFO rule. With the formulas, OHTs can be sent just-in-time to tools to load or unload wafer cassettes, and wafer lots can be assigned while minimizing the transient periods. In addition, the estimated completion time can be utilized in the planning and scheduling of wafer fabrication processes.

Auteurs: Jun-Ho Lee;Hyun-Jung Kim;
Apparue dans: IEEE Transactions on Automation Science and Engineering
Date publication: 10.-2017, volume: 14, issue:4, pages: 1622 - 1633
Editeur: IEEE
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» Complexity Reduction by Modified Scale-Space Construction in SIFT Generation Optimized for a Mobile GPU
Résumé:
Scale-invariant feature transform (SIFT) is one of the most widely used local features for computer vision in mobile devices. A mobile graphic processing unit (GPU) is often used to run computer-vision applications using SIFT features, but the performance in such a case is not powerful enough to generate SIFT features in real time. This paper proposes an efficient scheme to optimize the SIFT algorithm for a mobile GPU. It analyzes the conventional scale-space construction step in the SIFT generation, finding that reducing the size of the Gaussian filter and the scale-space image leads to a significant speedup with only a slight degradation of the quality of the features. Based on this observation, the SIFT algorithm is modified and implemented for real-time execution. Additional optimization techniques are employed for a further speedup by efficiently utilizing both the CPU and the GPU in a mobile processor. The proposed SIFT generation scheme achieves a processing speed of 28.30 frames/s for an image with a resolution of $1280 \times 720$ running on a Galaxy S5 LTE-A device, thereby gaining a speedup by the factors of 114.78 and 4.53 over CPU- and GPU-only implementations, respectively.
Auteurs: Chulhee Lee;Chae Eun Rhee;Hyuk-Jae Lee;
Apparue dans: IEEE Transactions on Circuits and Systems for Video Technology
Date publication: 10.-2017, volume: 27, issue:10, pages: 2246 - 2259
Editeur: IEEE
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» Complexity Reduction for the Optimization of Linear Precoders Over Random MIMO Channels
Résumé:
Precoder optimization with full channel state information for finite alphabet signals over multiple-input multiple-output random channels is investigated in this paper. The precoder is represented by a product of power allocation matrix and constellation-forming matrix. There was an optimal algorithm introduced in the literature to globally maximize the channel mutual information by iteratively optimizing these two matrices. However, the computational complexity of the optimal algorithm is painfully high, especially when it is used with the high-order modulation and the high-data stream number. In this paper, we propose a novel sub-optimal low-complexity precoding algorithm and compare it with the optimal one. The new algorithm proceeds in two steps. First, the constellation-forming matrix is fixed in order to maximize the minimum Euclidean distance between the received symbols, which ensures high channel mutual information. Then, given the constellation-forming matrix, an iterative algorithm searches for the power allocation matrix that maximizes the channel mutual information. Since optimizing only one matrix instead of two, the new algorithm not only achieves a lower computational complexity but also avoids the use of initial values, which must be carefully selected for each channel and signal-to-noise ratio for fast convergence. Another advantage of the new algorithm is that the resulting precoder has a fixed form of received constellation thanks to the fixed constellation-forming matrix. This allows us to optimize the symbol mapping on the received constellation. Simulation results show that the proposed low-complexity precoder achieves error-rate performance that is close to performance of the optimal one when the conventional mapping is used. In addition, the new precoder used with optimized mapping at received constellation shows significant error-rate performance improvement.
Auteurs: Nhat-Quang Nhan;Philippe Rostaing;Karine Amis;Ludovic Collin;Emanuel Radoi;
Apparue dans: IEEE Transactions on Communications
Date publication: 10.-2017, volume: 65, issue:10, pages: 4205 - 4217
Editeur: IEEE
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» Composability Verification of Multi-Service Workflows in a Policy-Driven Cloud Computing Environment
Résumé:
The emergence of cloud computing infrastructure and Semantic Web technologies has created unprecedented opportunities for composing large-scale business processes and workflow-based applications that span multiple organizational domains. A key challenge related to composition of such multi-organizational business processes and workflows is posed by the security and access control policies of the underlying organizational domains. In this paper, we propose a framework for verifying secure composability of distributed workflows in an autonomous multi-domain environment. The objective of workflow composability verification is to ensure that all the users or processes executing the designated workflow tasks conform to the time-dependent security policy specifications of all collaborating domains. A key aspect of such verification is to determine the time-dependent schedulability of distributed workflows, assumed to be invoked on a recurrent basis. We use a two-step approach for verifying secure workflow composability. In the first step, a distributed workflow is decomposed into domain-specific projected workflows and is verified for conformance with the respective domain's security and access control policy. In the second step, the cross-domain dependencies amongst the workflow tasks performed by different collaborating domains are verified.
Auteurs: Basit Shafiq;Sameera Ghayyur;Ammar Masood;Zahid Pervaiz;Abdulrahman Almutairi;Farrukh Khan;Arif Ghafoor;
Apparue dans: IEEE Transactions on Dependable and Secure Computing
Date publication: 10.-2017, volume: 14, issue:5, pages: 478 - 493
Editeur: IEEE
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» Compression-Based Compressed Sensing
Résumé:
Modern compression codes exploit signals’ complex structures to encode them very efficiently. On the other hand, compressed sensing algorithms recover “structured” signals from their under-determined set of linear measurements. Currently, there is a noticeable gap between the types of structures used in the area of compressed sensing and those employed by state-of-the-art compression codes. Recent results in the literature on deterministic signals aim at bridging this gap through devising compressed sensing decoders that employ compression codes. This paper focuses on structured stochastic processes and studies application of lossy compression codes to compressed sensing of such signals. The performance of the formerly proposed compressible signal pursuit (CSP) optimization is studied in this stochastic setting. It is proved that in the low-distortion regime, as the blocklength grows to infinity, the CSP optimization reliably and robustly recovers $n$ instances of a stationary process from its random linear measurements as long as $n$ is slightly more than $n$ times the rate-distortion dimension (RDD) of the source. It is also shown that under some regularity conditions, the RDD of a stationary process is equal to its information dimension. This connection establishes the optimality of CSP at least for memoryless stationary sources, which have known fundamental limits. Finally, it is shown that CSP combined by a family of universal variable-length fixed-distortion compression codes yields a family of universal compressed sensing recovery algorithms.
Auteurs: Farideh E. Rezagah;Shirin Jalali;Elza Erkip;H. Vincent Poor;
Apparue dans: IEEE Transactions on Information Theory
Date publication: 10.-2017, volume: 63, issue:10, pages: 6735 - 6752
Editeur: IEEE
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» Compressive Sensing as Applied to Inverse Problems for Imaging: Theory, Applications, Current Trends, and Open Challenges.
Résumé:
Compressive sensing (CS) is currently one the most active research fields in information engineering and science. The flexibility, robustness, accuracy, effectiveness, and sound theory behind such a paradigm have motivated a great interest in developing and applying CS to many domains, including inverse scattering. Unfortunately, electromagnetic imaging problems have some unique theoretical features that prevent a straightforward exploitation of CS tools. Therefore, suitable CS-based strategies must be considered in such a framework.
Auteurs: Giacomo Oliveri;Marco Salucci;Nicola Anselmi;Andrea Massa;
Apparue dans: IEEE Antennas and Propagation Magazine
Date publication: 10.-2017, volume: 59, issue:5, pages: 34 - 46
Editeur: IEEE
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» Compressive Sensing Techniques for mm-Wave Nondestructive Testing of Composite Panels
Résumé:
This paper presents imaging results from measurements of an industrially manufactured composite test panel, utilizing two introduced algorithms for data postprocessing. The system employs a planar near-field scanning setup for characterizing defects in composite panels in the 50–67-GHz band, and can be considered as a complementary diagnostic tool for nondestructive testing purposes. The introduced algorithms are based on the reconstruction of the illuminating source at the transmitter, enabling a separation of the sampled signal with respect to the location of its potential sources, the scatterers within the device under test or the transmitter. For the second algorithm, an $L_{1}$ -minimization problem formulation is introduced that enables compressive sensing techniques to be adapted for image retrieval. The algorithms are benchmarked against a more conventional imaging technique, based on the Fourier transform, and it is seen that the complete imaging system provides increased dynamic range, improved resolution, and reduced measurement time by removal of a reference measurement. Moreover, the system provides stable image quality over a range of frequencies.
Auteurs: Jakob Helander;Andreas Ericsson;Mats Gustafsson;Torleif Martin;Daniel Sjöberg;Christer Larsson;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 10.-2017, volume: 65, issue:10, pages: 5523 - 5531
Editeur: IEEE
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» Computable Delay Margins for Adaptive Systems With State Variables Accessible
Résumé:
Robust adaptive control of plants whose state variables are accessible in the presence of an input time delay is established in this paper. It is shown that a standard model reference adaptive controller modified with projection ensures global boundedness of the overall adaptive system for a range of nonzero delays. The upper bound of such delays, that is, the delay margin, is explicitly defined and can be computed a priori.
Auteurs: Heather S. Hussain;Yildiray Yildiz;Megumi Matsutani;Anuradha M. Annaswamy;Eugene Lavretsky;
Apparue dans: IEEE Transactions on Automatic Control
Date publication: 10.-2017, volume: 62, issue:10, pages: 5039 - 5054
Editeur: IEEE
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» Concealment of Chaos Time-Delay Signature Through Phase-Conjugate Feedback and Chaos Optical Injection
Résumé:
In this paper, we numerically demonstrate that the concealment of time-delay signature (TDS) can be readily achieved via the combined mechanism of phase-conjugate feedback (PCF) and chaotic optical injection. To show the potential advantages of the proposed scheme, its counterpart, i.e., a slave semiconductor laser (SSL) subjected to chaotic optical injection from a master semiconductor laser (MSL) with conventional optical feedback (COF) is studied in parallel. In particular, we consider a fair situation where the MSL in both PCF and COF shows a comparable peak value in the autocorrelation function computed from the intensity time series. Our simulations uncover that combining the mechanism of PCF and chaotic optical injection is beneficial for TDS concealment in the SSL. To better understand this, the effects of some control parameters including injection and feedback are comparably studied. The results further prove that, as the injection or feedback parameters are varied, the proposed PCF-system always exhibits weaker autocorrelation around the feedback delay value when compared to the COF-system. In the meantime, the former system allows for larger bandwidth and, thus, paves way for important applications to secure communication and random-number generation.
Auteurs: Penghua Mu;Wei Pan;Lianshan Yan;Bin Luo;Xihua Zou;
Apparue dans: IEEE Photonics Journal
Date publication: 10.-2017, volume: 9, issue:5, pages: 1 - 8
Editeur: IEEE
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