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Publications dans les journaux scientifiques dans le domaine de l'ingénierie : 02-2018 trié par par titre, page: 5
» Efficient Decoupling Capacitor Placement Based on Driving Point Impedance
Résumé:
With rapidly increasing switching speeds and surge current requirements, placement of local decoupling capacitors is becoming critically important in high-speed low-power designs. In this paper, utilizing the driving-point impedance (viewed from the device pin) as a metric, a new method is presented for the placement of decoupling capacitors in parallel-plate power ground pairs of high-speed circuits. In the proposed approach, instead of using the traditional trial-and-error method to identify an appropriate placement distance, the process is formulated in the form of a transcendental function. The resulting function is solved using Newton–Raphson (N-R) iterations to give a direct solution for the distance. Also, an analytical representation based on Hankel functions for the driving point impedance and its derivatives is developed to speed up the N-R iterations. The proposed method is validated by comparing the results with the full-wave electromagnetic simulations.
Auteurs: Ihsan Erdin;Ramachandra Achar;
Apparue dans: IEEE Transactions on Microwave Theory and Techniques
Date publication: 02.-2018, volume: 66, issue:2, pages: 669 - 677
Editeur: IEEE
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» Efficient Distributed All-Pairs Algorithms: Management Using Optimal Cyclic Quorums
Résumé:
All Pairs problems occur in many research fields. The all-pairs problem requires all data elements to be paired with all other data elements. With the advent of new data intensive big data applications and increase in data size, methods to reduce memory foot print and distribute to work equally across compute nodes are needed. In this paper, we propose cyclic quorum sets for all-pairs algorithm computations to reduce memory foot print. We show that the cyclic quorum sets have a unique all-pairs property that allows for minimal data replication. The cyclic quorums set based computing requires only $N/sqrt{P}$ size memory, up to 50 percent smaller than the dual $N/sqrt{P}$ array implementations proposed earlier, and significantly smaller than solutions requiring all data in each node. Computation can be distributed efficiently and more importantly and are communication-less after initial data distribution, which is a huge advantage in minimizing computation time. Scaling from 16 to 512 cores (1 to 32 compute nodes), our application experiments on a real dataset demonstrated scalability with greater than 150x (super-linear) speedup with less than 1/4th the memory usage per node in our experiments.
Auteurs: Cory James Kleinheksel;Arun K. Somani;
Apparue dans: IEEE Transactions on Parallel and Distributed Systems
Date publication: 02.-2018, volume: 29, issue:2, pages: 391 - 404
Editeur: IEEE
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» Efficient Modeling and Analysis of the Multiple Air Hole Effect in Substrate-Integrated Waveguide
Résumé:
A wide spectrum of potential applications using substrate-integrated waveguide (SIW) technologies in conjunction with air hole regions is introduced, and an efficient analysis method to cope with the multiple air hole effect in the SIW is proposed where we present the generalized wave equation satisfying the boundary and phase matching conditions to solve the multiple air interface problem, which provides highly accurate dispersion characteristics over the whole frequency band. The proposed approach is compared with a commercial software and verified by measurement results from the fabricated samples using Taconic/RF30-7H substrate, and is confirmed to give excellent agreement. Hence, the proposed method is effective for optimum design of SIW circuits for the purpose of low-loss and broadband applications.
Auteurs: Jin-Yang Kim;Dong-Wan Chun;Hai-Young Lee;
Apparue dans: IEEE Microwave and Wireless Components Letters
Date publication: 02.-2018, volume: 28, issue:2, pages: 93 - 95
Editeur: IEEE
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» Efficient Receive Antenna Selection for Pre-Coding Aided Spatial Modulation
Résumé:
Developed from the recently emerged pre-coding aided spatial modulation (PSM) concept, a class of efficient receives antenna selection (ERAS) techniques are devised. Aiming at approaching the optimal RAS performance in context of the PAM system, we derive the upper bound performance of RAS-PAM in two different ways, by utilizing the condition number and eigenvalue and Wishart distribution feature for the channel matrix. Our performance results demonstrate that the proposed ERAS techniques are capable of effectively improving the transmission performance in comparison with conventional RAS-PSM systems.
Auteurs: Peibo Wen;Xu He;Yue Xiao;Ping Yang;Rong Shi;Ke Deng;
Apparue dans: IEEE Communications Letters
Date publication: 02.-2018, volume: 22, issue:2, pages: 416 - 419
Editeur: IEEE
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» Efficient Recommendation of Aggregate Data Visualizations
Résumé:
Data visualization is a common and effective technique for data exploration. However, for complex data, it is infeasible for an analyst to manually generate and browse all possible visualizations for insights. This observation motivated the need for automated solutions that can effectively recommend such visualizations. The main idea underlying those solutions is to evaluate the utility of all possible visualizations and then recommend the top-k visualizations. This process incurs high data processing cost, that is further aggravated by the presence of numerical dimensional attributes. To address that challenge, we propose novel view recommendation schemes, which incorporate a hybrid multi-objective utility function that captures the impact of numerical dimension attributes. Our first scheme, Multi-Objective View Recommendation for Data Exploration (MuVE), adopts an incremental evaluation of our multi-objective utility function, which allows pruning of a large number of low-utility views and avoids unnecessary objective evaluations. Our second scheme, upper MuVE (uMuVE), further improves the pruning power by setting the upper bounds on the utility of views and allowing interleaved processing of views, at the expense of increased memory usage. Finally, our third scheme, Memory-aware uMuVE (MuMuVE), provides pruning power close to that of uMuVE, while keeping memory usage within a pre-specified limit.
Auteurs: Humaira Ehsan;Mohamed A. Sharaf;Panos K. Chrysanthis;
Apparue dans: IEEE Transactions on Knowledge and Data Engineering
Date publication: 02.-2018, volume: 30, issue:2, pages: 263 - 277
Editeur: IEEE
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» Efficient Wideband Computation of Electromagnetic Scattering by Finite Periodic Structures Combining ASED Basis Function With Frequency-Independent Reaction
Résumé:
An efficient wideband electromagnetic scattering analysis method for finite periodic structures by combining the accurate subentire-domain (ASED) basis function with the frequency-independent reaction (FIR) is presented. The ASED basis function is suitable for analyzing finite periodic structures with less unknowns than the conventional method of moments (MoM). Its efficiency is very high. However, it is a single-frequency technique and is still time-consuming for frequency sweep. The FIR can accelerate the frequency sweep, in which the exponential of the Green function is expanded in Taylor series. The impedance element is formulated as the sum of the series, where each term is the product of the geometry-dependent element and the phase factor. Recomputation of the former one is unnecessary during frequency sweep. Thus, it is very efficient. To test the accuracy of the proposed algorithm, several examples are implemented. Numerical results show that the results obtained using the proposed method agree well with those computed using the ASED basis function and conventional MoM. The efficiency of the proposed technique is also validated.
Auteurs: Ping Du;Gang Zheng;Cheng Wang;Wei Jie Fu;
Apparue dans: IEEE Antennas and Wireless Propagation Letters
Date publication: 02.-2018, volume: 17, issue:2, pages: 234 - 237
Editeur: IEEE
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» ElasticCore: A Dynamic Heterogeneous Platform With Joint Core and Voltage/Frequency Scaling
Résumé:
Heterogeneous architectures have emerged as a promising solution to address the dark silicon challenge by providing customized cores for each running application. To harness the power of heterogeneity, a critical challenge is simultaneously fine-tuning several parameters at the application, architecture, system, as well as circuit levels for heterogeneous architectures that improve the energy-efficiency envelope. To address this challenge, an ElasticCore platform is described where core resources along with the operating voltage and frequency settings are scaled to match the application behavior at run-time. A quantile linear regression model for power and performance prediction is used to guide the adaptation of the core resources, along with the operating voltage and frequency, to improve the energy efficiency. In addition, the dynamically scalable partitions of the ElasticCore are powered with multiple on-chip voltage regulators with high-power conversion efficiency that are able to realize fast dynamic voltage/frequency scaling. The results indicate that ElasticCore predicts application power and performance behavior with a small error at run-time across all studied benchmarks and achieves, on average close to 93% energy efficiency, as compared to an architecture with the Oracle power and performance predictor.
Auteurs: Mohammad Khavari Tavana;Mohammad Hossein Hajkazemi;Divya Pathak;Ioannis Savidis;Houman Homayoun;
Apparue dans: IEEE Transactions on Very Large Scale Integration Systems
Date publication: 02.-2018, volume: 26, issue:2, pages: 249 - 261
Editeur: IEEE
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» Electrically Small, Low-Profile, Huygens Circularly Polarized Antenna
Résumé:
The design, simulation studies, and experimental verification of an electrically small, low-profile, broadside-radiating Huygens circularly polarized (HCP) antenna are reported. To realize its unique circular polarization cardioid-shaped radiation characteristics in a compact structure, two pairs of the metamaterial-inspired near-field resonant parasitic elements, the Egyptian axe dipole (EAD) and the capacitively loaded loop (CLL), are integrated into a crossed-dipole configuration. The EAD (CLL) elements act as the orthogonal electric dipole (magnetic dipole) radiators. Balanced broadside-radiated electric and magnetic field amplitudes with the requisite 90° phase difference between them are realized by exciting these two pairs of electric and magnetic dipoles with a specially designed, unbalanced crossed-dipole structure. The electrically small (ka = 0.73) design operates at 1575 MHz. It is low profile $0.04lambda _{mathbf {0}}$ , and its entire volume is only $0.0018lambda _{mathbf {0}}^{mathbf {3}}$ . A prototype of this optimized HCP antenna system was fabricated, assembled, and tested. The measured results are in good agreement with their simulated values. They demonstrate that the prototype HCP antenna resonates at 1584 MHz with a 0.6 dB axial ratio, and produces the predicted Huygens cardioid-shaped radiation patterns. The measured peak realized LHCP gain was 2.7 dBic, and the associated front-to-back ratio was 17.7 dB.
Auteurs: Wei Lin;Richard W. Ziolkowski;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 02.-2018, volume: 66, issue:2, pages: 636 - 643
Editeur: IEEE
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» Electrifying Water Buses: A Case Study on Diesel-to-Electric Conversion in Venice
Résumé:
This study presents the conversion of a diesel-based watercraft for public transportation in Venice, Italy, to an electric propulsion technology, with a view to wide future adoption of electrical transportation. It takes into account energy-storage systems, electrical machines, and drives and examines them in light of economic, environmental, and social issues. Some alternative solutions based on hybrid diesel-electric and full-electric (FE ) powertrains are compared in terms of weight, cost, and payback times. The comparison shows that a hybrid diesel-engine lithium (Li) battery (LB) is the best option for an easy first implementation, even when considering the existing infrastructure.
Auteurs: Massimo Guarnieri;Mattia Morandin;Antonio Ferrari;Pierpaolo Campostrini;Silverio Bolognani;
Apparue dans: IEEE Industry Applications Magazine
Date publication: 02.-2018, volume: 24, issue:1, pages: 71 - 83
Editeur: IEEE
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» Electron Acceleration and Diffusion in the Gyrophase Space by Low-Frequency Electromagnetic Waves
Résumé:
Charged particle acceleration is a fundamental issue in many fields ranging from particle physics to spacecraft propulsion. In this paper, the interaction between electromagnetic waves and relativistic electrons is numerically studied. The effect of the initial gyrophase in a dipole magnetic field on electron acceleration by wave–particle interaction is found in a test particle code with various wave amplitudes. It is indicated that the initial gyrophase of the electrons plays a crucial role in the acceleration process.
Auteurs: Hua Huang;Xiao-Tian Gao;Xiao-Gang Wang;Zhi-Bin Wang;
Apparue dans: IEEE Transactions on Plasma Science
Date publication: 02.-2018, volume: 46, issue:2, pages: 225 - 229
Editeur: IEEE
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» Electronic Interface for a Gas Sensor System Based on 32 MHz QCMs: Design and Calibration
Résumé:
This paper describes the design and development of a system of gas sensors based on quartz crystal microbalances (QCMs) to be used for the measurement of gas, vapors, and their mixtures. This system’s architecture manages an array composed of eight QCMs with a resonance frequency of about 32 MHz. Custom oscillator circuits were designed and built to drive the QCMs. A data acquisition stage was developed to collect the output frequencies of the QCMs array and to visualize and store the data. The QCMs have been functionalized with eight different types of anthocyanins, using two different techniques. Three of the QCMs composing the array have been tested, and their performance is compared to a previous array based on 20-MHz QCMs. One of the QCMs, covered via drop casting, when tested in a calibration experiment, shown an improved performance consisting in a ratio of 4.92 between 32- and 20-MHz sensitivities. This number confirmed the ratio of 5.76 theoretically calculated using Sauerbrey’s law. The other two QCMs tested were covered via spray casting, giving resolution of tens of ppb, comparable with the previous release.
Auteurs: Giorgio Pennazza;Marco Santonico;Alessandro Zompanti;Simone Grasso;Arnaldo D’Amico;
Apparue dans: IEEE Sensors Journal
Date publication: 02.-2018, volume: 18, issue:4, pages: 1419 - 1426
Editeur: IEEE
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» Electronically Tunable Fully Integrated Fractional-Order Resonator
Résumé:
A fully integrated implementation of a parallel fractional-order resonator that employs together a fractional-order capacitor and a fractional-order inductor is proposed in this brief. The design utilizes current-controlled operational transconductance amplifiers as building blocks, designed, and fabricated in AMS ${0.35{-}mu {mathrm{ m}}}$ CMOS process and based on a second-order approximation of a fractional-order differentiator/integrator magnitude optimized in the range 10 Hz–700 Hz. An attractive benefit of the proposed scheme is its electronic tuning capability.
Auteurs: Georgia Tsirimokou;Costas Psychalinos;Ahmed S. Elwakil;Khaled N. Salama;
Apparue dans: IEEE Transactions on Circuits and Systems II: Express Briefs
Date publication: 02.-2018, volume: 65, issue:2, pages: 166 - 170
Editeur: IEEE
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» Elevating Learner Achievement Using Formative Electronic Lab Assessments in the Engineering Laboratory: A Viable Alternative to Weekly Lab Reports
Résumé:
A laboratory pedagogy interweaving weekly student portfolios with onsite formative electronic laboratory assessments (ELAs) is developed and assessed within the laboratory component of a required core course of the electrical and computer engineering (ECE) undergraduate curriculum. The approach acts to promote student outcomes, and neutralize academic integrity violations, while refocusing instructor and teaching assistant roles toward high-gain instructional activities, such as personalized student tutoring. A mixed-method study evaluated the learning effectiveness and student satisfaction using biweekly ELAs versus traditional laboratory reports in a large-enrollment ( ${N}=68$ ) undergraduate computer engineering laboratory course. The results of the evaluation indicate statistically significant effects on both learning outcomes and student satisfaction from the use of formative assessments in laboratory delivery, which were corroborated by the instructor’s reflections. Students in the ELA with tutoring enabled delivery cohort performed better on the post-test and were more satisfied with the laboratory assessment design and assistance received in laboratory than those in the control cohort. The findings offer a promising alternative for ECE and engineering laboratory instruction that fosters gains in practical skills and content mastery.
Auteurs: Baiyun Chen;Ronald F. DeMara;Soheil Salehi;Richard Hartshorne;
Apparue dans: IEEE Transactions on Education
Date publication: 02.-2018, volume: 61, issue:1, pages: 1 - 10
Editeur: IEEE
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» Empirical Model for Electrical Activation of Aluminum- and Boron-Implanted Silicon Carbide
Résumé:
Accurate modeling of the electrical properties of impurities in semiconductors is essential for the mandatory support of the development of novel semiconductor devices by means of simulations. An appropriate modeling approach to determine the activation rate of dopants in silicon carbide is currently not available, which limits the predictability of process simulations. To remedy this fact, we propose an empirical model for the electrical activation of aluminum and boron impurities in silicon carbide for various annealing temperatures and total doping concentrations. The differences of the two acceptor-type dopants are discussed according to the model predictions and the activation ratios for various processing parameters are presented. The model was implemented into Silvaco’s simulation platform Victory Process and evaluated with respect to published experimental findings.
Auteurs: Vito Šimonka;Andreas Hössinger;Josef Weinbub;Siegfried Selberherr;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 02.-2018, volume: 65, issue:2, pages: 674 - 679
Editeur: IEEE
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» Employing DC Transmission in Long Distance AC Motor Drives: Analysis of the Copper Economy and Power Losses Reduction in Mining Facilities
Résumé:
High-frequency problems related to pulse-width modulation motor drive systems with long cables are widely discussed in the literature and very harmful to the system components, resulting in motor insulation failures, bearing damage, and electromagnetic interference, among others. As a solution, in a previous work, an alternative system configuration was proposed in which the rectifier and the inverter are separated through a long dc cable, the inverter being located at the motor terminals. Thus, besides the mitigation of all these problems, the proposed topology also features the additional benefit of reducing the cable power losses and the amount of copper required for the power transmission. In this context, this paper evaluates the copper economy obtained through this alternative drive configuration and presents a case study involving real motor drive systems situated in mining plants, whose actual cost of the cables is compared with that of the alternative configuration.
Auteurs: Vinicius Cardoso de Paula;Hélder de Paula;
Apparue dans: IEEE Transactions on Industry Applications
Date publication: 02.-2018, volume: 54, issue:1, pages: 841 - 847
Editeur: IEEE
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» Enabling a Nationwide Radio Frequency Inventory Using the Spectrum Observatory
Résumé:
Knowledge about active radio transmitters is critical for multiple applications: spectrum regulators can use this information to assign spectrum, licensees can identify spectrum usage patterns and provision their future needs, and dynamic spectrum access applications can efficiently pick operating frequency. To achieve these goals, we need a system that continuously senses and characterizes the radio spectrum. Current measurement systems, however, do not scale over time, frequency and space and cannot perform transmitter detection. We address these challenges with the Spectrum Observatory, an end-to-end system for spectrum measurement and characterization. This paper details the design and integration of the Spectrum Observatory, and describes and evaluates the first unsupervised method for detailed characterization of arbitrary transmitters called TxMiner. We evaluate TxMiner on real-world spectrum measurements collected by the Spectrum Observatory between 30 MHz and 6 GHz and show that it identifies transmitters robustly. Furthermore, we demonstrate the Spectrum Observatory’s capabilities to map the number of active transmitters and their frequency and temporal characteristics, to detect rogue transmitters, and identify opportunities for dynamic spectrum access.
Auteurs: Mariya Zhivkova Zheleva;Ranveer Chandra;Aakanksha Chowdhery;Paul Garnett;Anoop Gupta;Ashish Kapoor;Matt Valerio;
Apparue dans: IEEE Transactions on Mobile Computing
Date publication: 02.-2018, volume: 17, issue:2, pages: 362 - 375
Editeur: IEEE
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» Endocardial Energy Harvesting by Electromagnetic Induction
Résumé:
Objective: cardiac pacemakers require regular medical follow-ups to ensure proper functioning. However, device replacements due to battery depletion are common and account for ∼25% of all implantation procedures. Furthermore, conventional pacemakers require pacemaker leads which are prone to fractures, dislocations or isolation defects. The ensuing surgical interventions increase risks for the patients and costs that need to be avoided. Methods: in this study, we present a method to harvest energy from endocardial heart motions. We developed a novel generator, which converts the heart's mechanical into electrical energy by electromagnetic induction. A mathematical model has been introduced to identify design parameters strongly related to the energy conversion efficiency of heart motions and fit the geometrical constraints for a miniaturized transcatheter deployable device. The implemented final design was tested on the bench and in vivo. Results : the mathematical model proved an accurate method to estimate the harvested energy. For three previously recorded heart motions, the model predicted a mean output power of 14.5, 41.9, and 16.9 μW. During an animal experiment, the implanted device harvested a mean output power of 0.78 and 1.7 μW at a heart rate of 84 and 160 bpm, respectively. Conclusion: harvesting kinetic energy from endocardial motions seems feasible. Implanted at an energetically favorable location, such systems might become a welcome alternative to extend the lifetime of cardiac implantable electronic device. Significance: the presented endocardial energy harvesting concept has the potential to turn pacemakers into battery- and leadless systems and thereby eliminate two major drawbacks of contemporary systems.
Auteurs: Adrian Zurbuchen;Andreas Haeberlin;Lukas Bereuter;Alois Pfenniger;Simon Bosshard;Micha Kernen;Paul Philipp Heinisch;Juerg Fuhrer;Rolf Vogel;
Apparue dans: IEEE Transactions on Biomedical Engineering
Date publication: 02.-2018, volume: 65, issue:2, pages: 424 - 430
Editeur: IEEE
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» Ends and Means
Résumé:
Even the smallest coding mistake can cause huge problems when it slips by testing. Finding it can be difficult, and retesting the fixed system can be expensive, but this certainly isn't true for every type of problem. A defect found and fixed during coding is a fairly routine occurrence and not costlier than a defect found and fixed during design. Quite the opposite is usually true.
Auteurs: Gerard J. Holzmann;
Apparue dans: IEEE Software
Date publication: 02.-2018, volume: 35, issue:1, pages: 14 - 17
Editeur: IEEE
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» Energy Consumption Enhancement of Reverse-Biased Silicon-Based Mach–Zehnder Modulators Using Corrugated Slow Light Waveguides
Résumé:
The energy efficiency of silicon modulators can be enhanced by increasing the doping level. As an alternative solution, slow light modulators based on corrugated waveguides can also be used for improving the energy efficiency. Using numerical and analytical tools, we show that for the same level of energy consumption reduction, the loss coefficient and the loss-modulation efficiency for the slow-light modulators are smaller than those for the modulators with an increased doping level. It is shown that the slow light structures with medium slow down factors (specifically slowdown factors of less than 6) can be reasonable candidates for enhancing the modulator's energy efficiency. For example, an energy consumption of less than 100 fJ/bit can be achieved at a slow-down factor of 6, using a doping level of 5 × 1017 cm-3 for acceptors and 1 × 1018 cm-3 for donors.
Auteurs: Reza Hosseini;Levon Mirzoyan;Kambiz Jamshidi;
Apparue dans: IEEE Photonics Journal
Date publication: 02.-2018, volume: 10, issue:1, pages: 1 - 7
Editeur: IEEE
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» Energy Efficiency in Cache-Enabled Small Cell Networks With Adaptive User Clustering
Résumé:
Using a network of cache enabled small cells, traffic during peak hours can be reduced by proactively fetching the content that is most likely to be requested. In this paper, we aim to explore the impact of proactive caching on an important metric for future generation networks, namely, energy efficiency (EE). We argue that, exploiting the spatial repartitions of users in addition to the correlation in their content popularity profiles, can result in considerable improvement of the achievable EE. In this paper, the optimization of EE is decoupled into two related subproblems. The first one addresses the issue of content popularity modeling. While most existing works assume similar popularity profiles for all users, we consider an alternative framework in which, users are clustered according to their popularity profiles. In order to showcase the utility of the proposed clustering, we use a statistical model selection criterion, namely, Akaike information criterion. Using stochastic geometry, we derive a closed-form expression of the achievable EE and we find the optimal active small cell density vector that maximizes it. The second subproblem investigates the impact of exploiting the spatial repartitions of users. After considering a snapshot of the network, we formulate a combinatorial problem that optimizes content placement in order to minimize the transmission power. Numerical results show that the clustering scheme considerably improves the cache hit probability and consequently the EE, compared with an unclustered approach. Simulations also show that the small base station allocation algorithm improves the energy efficiency and hit probability.
Auteurs: Salah Eddine Hajri;Mohamad Assaad;
Apparue dans: IEEE Transactions on Wireless Communications
Date publication: 02.-2018, volume: 17, issue:2, pages: 955 - 968
Editeur: IEEE
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» Energy-Efficient and Distributed Network Management Cost Minimization in Opportunistic Wireless Body Area Networks
Résumé:
Mobility induced by limb/body movements in Wireless Body Area Networks (WBANs) significantly affects the link-quality of intra-BAN and inter-BAN communication units, which, in turn, affects the Quality-of-Service (QoS) of each WBAN, in terms of reliability, efficient data transmission and network throughput guarantees. Further, the variation in link-quality between WBANs and Access Points (APs) makes the WBAN-equipped patients more resource-constrained in nature, which also increases the data dissemination delay. Therefore, to minimize the data dissemination delay of the network, WBANs send patients’ physiological data to local servers using the proposed opportunistic transient connectivity establishment algorithm. Additionally, limb/body movements induce dynamic changes to the on-body network topology, which, in turn, increases the network management cost and decreases the life-time of the sensor nodes periodically. Also, mutual and cross technology interference among coexisting WBANs and other radio technologies increases the energy consumption rate of the sensor nodes and also the energy management cost. To address the problem of increased network management cost and data dissemination delay, we propose a network management cost minimization framework to optimize the network throughput and QoS of each WBAN. The proposed framework attempts to minimize the dynamic connectivity, interference management, and data dissemination costs for opportunistic WBAN. We have, theoretically, analyzed the performance of the proposed framework to provide reliable data transmission in opportunistic WBANs. Simulation results show significant improvement in the network performance compared to the existing solutions.
Auteurs: Amit Samanta;Sudip Misra;
Apparue dans: IEEE Transactions on Mobile Computing
Date publication: 02.-2018, volume: 17, issue:2, pages: 376 - 389
Editeur: IEEE
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» Energy-Efficient Sensor Data Collection Approach for Industrial Process Monitoring
Résumé:
The use of wireless sensor network for industrial applications has attracted much attention from both academic and industrial sectors. It enables a continuous monitoring, controlling, and analyzing of the industrial processes, and contributes significantly to finding the best performance of operations. Sensors are typically deployed to gather data from the industrial environment and to transmit it periodically to the end user. Since the sensors are resource constrained, effective energy management should include new data collection techniques for an efficient utilization of the sensors. In this paper, we propose adaptive data collection mechanisms that allow each sensor node to adjust its sampling rate to the variation of its environment, while at the same time optimizing its energy consumption. We provide and compare three different data collection techniques. The first one uses the analysis of data variances via statistical tests to adapt the sampling rate, whereas the second one is based on the set-similarity functions, and the third one on the distance functions. Both simulation and real experimentations on telosB motes were performed in order to evaluate the performance of our techniques. The obtained results proved that our proposed adaptive data collection methods can reduce the number of acquired samples up to 80% with respect to a traditional fixed-rate technique. Furthermore, our experimental results showed significant energy savings and high accurate data collection compared to existing approaches.
Auteurs: Hassan Harb;Abdallah Makhoul;
Apparue dans: IEEE Transactions on Industrial Informatics
Date publication: 02.-2018, volume: 14, issue:2, pages: 661 - 672
Editeur: IEEE
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» Engineering the Structural Nonlinearity Using Multimodal-Shaped Springs in MEMS
Résumé:
The purpose of this paper is to introduce a novel technique to engineer in a precise way the structural nonlinearity in MEMS springs. To perform the adjustment of structural nonlinearity, the idea of using a sine-shaped beam following the combination of the natural bending modes of a straight one is explored to create a multimodal-shaped spring. The basic analytical model of multimodal beam bending is introduced and validated with finite element modeling. Proposed multimodal springs are fabricated by deep reactive ion etching on silicon on insulator wafer and their force-displacement characteristics are extracted using a force probe, with the resulting curves being close to the ones predicted by the theoretical calculations. The presented spring allows the engineering of structural nonlinearity by varying the amplitudes of the different modes used as initial shape. Thus, a straightforward method to create any type of structural nonlinearity starting from fully bistable up to the linear case, without the need to combine springs of several types, reducing the complexity of the targeted systems and their footprint. The proposed methodology was used to successfully design a suspension spring that exhibits flat force-displacement region with the aim to increase the bandwidth of vibrational energy harvesters. [2017-0250]
Auteurs: Bogdan Vysotskyi;Fabien Parrain;Denis Aubry;Philippe Gaucher;Xavier Le Roux;Elie Lefeuvre;
Apparue dans: Journal of Microelectromechanical Systems
Date publication: 02.-2018, volume: 27, issue:1, pages: 40 - 46
Editeur: IEEE
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» Enhance In-Hand Dexterous Micromanipulation by Exploiting Adhesion Forces
Résumé:
Micromanipulation plays a key role in the development of complex and assembled microsystems. However, current micromanipulation solutions are often limited to small rotation amplitudes and to simple shaped objects (such as cubes). Our approach consists of developing in-hand micromanipulation techniques using dexterous microhands to manipulate arbitrary shaped objects and to perform large rotations. This paper focuses on the trajectory generation of a dexterous microhand to achieve automated repositioning by taking advantage of adhesion forces. The results on the generated trajectories show that adhesion forces can be exploited to enhance the manipulation possibilities. Moreover, experiments show that planed rotations are performed at more than $text{95}%$ using an open-loop control. Dexterous micromanipulation is a promising way to perform complex manipulation tasks in microscale.
Auteurs: Jean-Antoine Seon;Redwan Dahmouche;Michaël Gauthier;
Apparue dans: IEEE Transactions on Robotics
Date publication: 02.-2018, volume: 34, issue:1, pages: 113 - 125
Editeur: IEEE
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» Enhanced Electrical Performance and Negative Bias Illumination Stability of Solution-Processed InZnO Thin-Film Transistor by Boron Addition
Résumé:
In this paper, boron-doped indium–zinc–oxide (InZnO) thin-film transistors (BIZO TFTs) were fabricated by solution process. The electrical performance and stability under the negative bias illumination stress (NBIS) have been greatly improved by B doping. The BIZO TFT with 5 mol.% B doping ratio shows a superior electrical performance with a field-effect mobility of 10.15 cm2/ $textsf {V},cdot , textsf {s}$ , a threshold voltage of 3.29 V, a subthreshold swing of 0.35 V/decade, and an ON/OFF ratio of 108. Furthermore, the 5 mol.% BIZO TFT shows only a −1.59 V shift of the threshold voltage, compared with a large negative shift of −4.24 V for pure IZO TFTs. The enhancement of electrical performance and stability under NBIS is due to the reduction of oxygen vacancies, which are suppressed by B doping. The density of states is calculated to further validate the improved electrical performance and NBIS stability of BIZO TFTs.
Auteurs: De-Yao Zhong;Jun Li;Cheng-Yu Zhao;Chuan-Xin Huang;Jiang-Hua Zhang;Xi-Feng Li;Xue-Yin Jiang;Zhi-Lin Zhang;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 02.-2018, volume: 65, issue:2, pages: 520 - 525
Editeur: IEEE
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» Enhanced Hydrated Lime—A Simple Solution for Acid Gas Compliance
Résumé:
The U.S. landscape of environmental regulations is complex and continues to evolve requiring more stringent acid gas emission limits than ever. Current regulations include acid gas emission requirements via the Portland Cement National Emission Standard for Hazardous Air Pollutants, consent decrees, and revised operating permits, where operational modifications are made requiring additional acid gas removal. As a result of the need to comply with these increasingly stringent acid gas emission limits, there is a growing desire for a relatively simple solution. Dry sorbent injection (DSI) technology offers a low capital cost solution with a relatively small equipment footprint, low power consumption, and ease of retrofit to a majority of existing facilities. As DSI technology has matured, the systems have become more reliable and advancements in calcium based sorbents have provided new compliance solutions that were not available in past years. The optimization of the physical properties of enhanced hydrated lime products has demonstrated upward of 90% sulfur dioxide and 95+% hydrochloric acid reduction with the DSI technology over a range of applications, and has been consistently successful achieving cement plant's acid gas removal needs to meet their regulatory requirements.
Auteurs: Gerald Hunt;Johan J. Heiszwolf;Melissa Sewell;
Apparue dans: IEEE Transactions on Industry Applications
Date publication: 02.-2018, volume: 54, issue:1, pages: 796 - 807
Editeur: IEEE
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» Enhanced Model and Real-Time Simulation Architecture for Modular Multilevel Converter
Résumé:
This paper presents i) an equivalent model of the half-bridge modular multilevel converter (HB-MMC) which is suitable for real-time applications, ii) a hybrid central-processing unit/field-programmable gate array (CPU/FPGA)-based architecture for real-time simulation of electromagnetic transients of systems which include HB-MMC, and iii) a novel arrangement for sorting results referred to as the “sub-module (SM) rank list”, which tackles the bottleneck for parallel implementation of the MMC arm model solver on the FPGA. The Adam–Bashforth (AB) method is used for numerical integration of the HB-SM capacitor model. The second-order AB method provides a constant admittance matrix of the HB-MMC and, thus, reduces computational burden while offering the same accuracy as that of the widely used Trapezoidal method. The CPU/FPGA-based architecture is optimized to obtain maximum parallelism of the HB-MMC model implementation, adopting a standard, single-precision, floating-point computational engine. The proposed sorting arrangement is independent of the utilized sorting algorithm and its application to the odd–even bubble sorting scheme is presented in this paper. The proposed architecture offers a simulation time-step of 825 ns while including the sorting module as the SM capacitor voltage-balancing control unit. This enables accurate analysis of MMC controls based on either software-in-the-loop or hardware-in-the-loop approaches. Performance and accuracy of the MMC model and the hybrid CPU/FPGA-based architecture are evaluated based on a set of case studies on a 401-level HB-MMC-based HVDC station and verified based on offline simulation results in the PSCAD/EMTDC environment.
Auteurs: Mojtaba Ashourloo;Ramin Mirzahosseini;Reza Iravani;
Apparue dans: IEEE Transactions on Power Delivery
Date publication: 02.-2018, volume: 33, issue:1, pages: 466 - 476
Editeur: IEEE
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» Enhancement of a Continuous Liquid Level Sensor Based on a Macro-Bend Polymer Optical Fiber Coupler
Résumé:
An approach to improve the side-coupling ratio of the macro-bend polymer optical fiber (POF) coupler is proposed in this paper. Two naked POFs are twisted and twined around a cylinder to achieve continuous liquid level sensing. Through filling the gap between the two twisted POFs with UV optical cement, both the sensitivity and the measurement range are increased substantially. The reversibility is also improved since the gap is eliminated, and little liquid can exist in the structure with the liquid level decreasing. The design turns out to be a good method to enhance the performance, and could also be applied in the displacement or stress sensing field.
Auteurs: Yingzi Zhang;Yulong Hou;Yanjun Zhang;Yanjun Hu;Liang Zhang;Xiaolong Gao;Huixin Zhang;Wenyi Liu;
Apparue dans: IEEE Photonics Journal
Date publication: 02.-2018, volume: 10, issue:1, pages: 1 - 6
Editeur: IEEE
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» Enhancement of Intercellular Electrical Synchronization by Conductive Materials in Cardiac Tissue Engineering
Résumé:
Objective: cardiac tissue regeneration for the treatment of cardiovascular diseases has been of great research interest. Under the hypothesis that electrical synchronization of cardiac cells can be aided by conductive materials, electrically conductive scaffolds have been frequently used to improve cardiac tissue regeneration. However, theoretical analysis is presently absent in examining the underlying mechanism and rationally guiding the design of these conductive scaffolds. Methods: here, equivalent-circuit models are proposed, in which two adjacent groups of cardiomyocytes are grown either on a bulk conductive substrate or around conductive nanostructures. When one group of cells leads with action potentials, the membrane depolarization of the following group is investigated. Results: this study reveals that membrane depolarization of the following group is most sensitive to seal resistance to the substrate while surface roughness and conductivity of the material have less influence. In addition, it is found that a multiple-cell group is easier to be depolarized by its adjacent beating cardiomyocytes. For nanostructure-bridged cardiac cells, substantial depolarization occurs only with a seal resistance larger than 1013 Ω/sqr, which is contradictory to many reported estimations. Conclusion: this work theoretically confirms the positive role of conductive scaffolds and nanostructures in aiding electrical synchronization of cardiac cells and reveals that its performance mainly relies on the cell-device interface. Significance: this work provides a theoretical basis for the rational design of electroactive scaffolds for enhanced cardiac tissue engineering.
Auteurs: Yu Wu;Liang Guo;
Apparue dans: IEEE Transactions on Biomedical Engineering
Date publication: 02.-2018, volume: 65, issue:2, pages: 264 - 272
Editeur: IEEE
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» Enhancing Selectivity in Big Data
Résumé:
Today’s companies collect immense amounts of personal data and enable wide access to it within the company. This exposes the data to external hackers and privacy-transgressing employees. This study shows that, for a wide and important class of workloads, only a fraction of the data is needed to approach state-of-the-art accuracy. We propose selective data systems that are designed to pinpoint the data that is valuable for a company’s current and evolving workloads. These systems limit data exposure by setting aside the data that is not truly valuable.
Auteurs: Mathias Lecuyer;Riley Spahn;Roxana Geambasu;Tzu-Kuo Huang;Siddhartha Sen;
Apparue dans: IEEE Security & Privacy
Date publication: 02.-2018, volume: 16, issue:1, pages: 34 - 42
Editeur: IEEE
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» Enhancing the Student Learning Experience in Software Engineering Project Courses
Résumé:
Carrying out real-world software projects in their academic studies helps students to understand what they will face in industry, and to experience first-hand the challenges involved when working collaboratively. Most of the instructional strategies used to help students take advantage of these activities focus on supporting agile programming, which is appropriate for capstone courses. This is not always recommended in initial software engineering project courses, however, where novice developers run projects in teams while simultaneously taking other courses. To enhance the learning and teamwork experience in this latter instructional scenario, this paper proposes a formative monitoring method, reflexive weekly monitoring (RWM), for use in project courses that involve disciplined software processes and loosely coupled work. RWM uses self-reflection and collaborative learning practices to help students be aware of their individual and team performance. RWM was applied in a case study over nine consecutive semesters. The results obtained indicate that RWM was effective in enhancing the learning experience in the instructional scenario studied. While students in the monitored teams were more effective and coordinated, and experienced a higher sense of team belonging and satisfaction, little evidence was found of them being more productive than students working in non-monitored teams.
Auteurs: Maíra Marques;Sergio F. Ochoa;María Cecilia Bastarrica;Francisco J. Gutierrez;
Apparue dans: IEEE Transactions on Education
Date publication: 02.-2018, volume: 61, issue:1, pages: 63 - 73
Editeur: IEEE
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» Ensemble of ESA/AATSR Aerosol Optical Depth Products Based on the Likelihood Estimate Method With Uncertainties
Résumé:
Within the European Space Agency Climate Change Initiative (CCI) project Aerosol_cci, there are three aerosol optical depth (AOD) data sets of Advanced Along-Track Scanning Radiometer (AATSR) data. These are obtained using the ATSR-2/ATSR dual-view aerosol retrieval algorithm (ADV) by the Finnish Meteorological Institute, the Oxford-Rutherford Appleton Laboratory (RAL) Retrieval of Aerosol and Cloud (ORAC) algorithm by the University of Oxford/RAL, and the Swansea algorithm (SU) by the University of Swansea. The three AOD data sets vary widely. Each has unique characteristics: the spatial coverage of ORAC is greater, but the accuracy of ADV and SU is higher, so none is significantly better than the others, and each has shortcomings that limit the scope of its application. To address this, we propose a method for converging these three products to create a single data set with higher spatial coverage and better accuracy. The fusion algorithm consists of three parts: the first part is to remove the systematic errors; the second part is to calculate the uncertainty and fusion of data sets using the maximum likelihood estimate method; and the third part is to mask outliers with a threshold of 0.12. The ensemble AOD results show that the spatial coverage of fused data set after mask is 148%, 13%, and 181% higher than those of ADV, ORAC, and SU, respectively, and the root-mean-square error, mean absolute error, mean bias error, and relative mean bias are superior to those of the three original data sets. Thus, the accuracy and spatial coverage of the fused AOD data set masked with a threshold of 0.12 are improved compared to the original data set. Finally, we discuss the selection of mask thresholds.
Auteurs: Yanqing Xie;Yong Xue;Yahui Che;Jie Guang;Linlu Mei;Dave Voorhis;Cheng Fan;Lu She;Hui Xu;
Apparue dans: IEEE Transactions on Geoscience and Remote Sensing
Date publication: 02.-2018, volume: 56, issue:2, pages: 997 - 1007
Editeur: IEEE
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» Equivalent Circuit of the Neuro-Electronic Junction for Signal Recordings From Planar and Engulfed Micro-Nano-Electrodes
Résumé:
In the latest years, several attempts to develop extracellular microtransducers to record electrophysiological activity of excitable cells have been done. In particular, many efforts have been oriented to increase the coupling conditions, and, thus, improving the quality of the recorded signal. Gold mushroom-shaped microelectrodes (GMμE) are an example of nano-devices to achieve those requirements. In this study, we developed an equivalent electrical circuit of the neuron–microelectrode system interface to simulate signal recordings from both planar and engulfed micro-nano-electrodes. To this purpose, models of the neuron, planar, gold planar microelectrode, and GMμE, neuro-electronic junction (microelectrode–electrolyte interface, cleft effect, and protein-glycocalyx electric double layer) are presented. Then, neuronal electrical activity is simulated by Hspice software, and analyzed as a function of the most sensitive biophysical models parameters, such as the neuron–microelectrode cleft width, spreading and seal resistances, ion-channel densities, double-layer properties, and microelectrode geometries. Results are referenced to the experimentally recorded electrophysiological neuronal signals reported in the literature.
Auteurs: Giuseppe Massobrio;Sergio Martinoia;Paolo Massobrio;
Apparue dans: IEEE Transactions on Biomedical Circuits and Systems
Date publication: 02.-2018, volume: 12, issue:1, pages: 3 - 12
Editeur: IEEE
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» Ergodic Rate of Millimeter Wave Ad Hoc Networks
Résumé:
In this paper, we use a stochastic geometry approach to quantify the ergodic rate of each user in an outdoor mm-wave ad hoc network. For a variety of use cases, it is reasonable to assume users will be clustered around a central point (e.g., WiFi hotspot or clusterhead) rather than uniformly distributed. Our results indicate that, in contrast to sub-6-GHz networks, clustered mm-wave ad hoc networks tolerate the increased interference because directional antenna arrays reduce the interference. For certain antenna array configurations and user densities, uncoordinated users within a cluster outperform TDMA. Additionally, we derive a scaling law for uniform mm-wave ad hoc networks and propose a heuristic scaling for clustered networks. The per user ergodic rate remains constant if mm-wave antenna arrays scale sub-linearly with the number of users for uniform networks or linearly in clustered networks as users are added to the cluster. Last, we compute expressions that quantify the loss in ergodic rate per user when alignment error occurs at the receiver and transmitter. Our results show that even relatively small errors in alignment can lead to significant ergodic rate reduction.
Auteurs: Andrew Thornburg;Robert W. Heath;
Apparue dans: IEEE Transactions on Wireless Communications
Date publication: 02.-2018, volume: 17, issue:2, pages: 914 - 926
Editeur: IEEE
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» Estimating the specific heat capacity and heating of electronic sensors and devices
Résumé:
Most sensors have three functional parts: the sensor part, signal conditioning part and interface part (Fig. 1). The sensor part senses the physical phenomena and transforms it typically into electric form. The signal condition part amplifies, linearizes and scales the electric signal. The interface part can be a simple mechanical connector, (field) bus adapter or in a wireless sensor, a radio module. Signal conditioning and interface parts are in most cases implemented by electronics.
Auteurs: Ilkka Korhonen;Jero Ahola;
Apparue dans: IEEE Instrumentation & Measurement Magazine
Date publication: 02.-2018, volume: 21, issue:1, pages: 54 - 62
Editeur: IEEE
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» Evaluation of DC Collector-Grid Configurations for Large Photovoltaic Parks
Résumé:
This paper presents a detailed comparison between the conventional ac collector-grid configuration and two proposed dc collector-grid configurations for large photovoltaic (PV) parks. One complete year of measured weather data at two different locations, one very sunny and the other with relatively less sun, is used for the evaluation. An already validated PV performance model is used to estimate the expected energy yield of the PV park for the given environmental and connection conditions. Loss mechanisms in different grid components in the three configurations are discussed based on the developed models. These components include the inverters, transformers, cables, and dc–dc converters. A comparison of the total losses in these components helps to identify the configuration that has the potential to operate at higher efficiency and, hence, generate maximum revenue. The economic viability metrics are calculated and a sensitivity analysis is carried out using the Monte Carlo method with a $pm mathbf { 5}{%}$ uncertainty in the considered cost and energy yield parameters.
Auteurs: Hafiz Abu Bakar Siddique;Rik W. De Doncker;
Apparue dans: IEEE Transactions on Power Delivery
Date publication: 02.-2018, volume: 33, issue:1, pages: 311 - 320
Editeur: IEEE
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» Evaluation of Local Error Estimators for the RWG-Based EFIE
Résumé:
Several error estimators suitable for use with the adaptive refinement solution of the electric field integral equation (EFIE) are investigated. The estimators are evaluated using a series of test problems for which correlation coefficients and scatter plots are computed. In addition, two new discontinuity estimators are introduced based on the combination of the charge discontinuity with the current or current discontinuity. The evaluations show that simple discontinuity estimators are as accurate for adaptive refinement as the EFIE residual estimator, and are far more computationally efficient.
Auteurs: Sang Kyu Kim;Andrew F. Peterson;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 02.-2018, volume: 66, issue:2, pages: 819 - 826
Editeur: IEEE
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» Evaluation of Parallel Level Sets and Bowsher’s Method as Segmentation-Free Anatomical Priors for Time-of-Flight PET Reconstruction
Résumé:
In this article, we evaluate Parallel Level Sets (PLS) and Bowsher’s method as segmentation-free anatomical priors for regularized brain positron emission tomography (PET) reconstruction. We derive the proximity operators for two PLS priors and use the EM-TV algorithm in combination with the first order primal-dual algorithm by Chambolle and Pock to solve the non-smooth optimization problem for PET reconstruction with PLS regularization. In addition, we compare the performance of two PLS versions against the symmetric and asymmetric Bowsher priors with quadratic and relative difference penalty function. For this aim, we first evaluate reconstructions of 30 noise realizations of simulated PET data derived from a real hybrid positron emission tomography/magnetic resonance imaging (PET/MR) acquisition in terms of regional bias and noise. Second, we evaluate reconstructions of a real brain PET/MR data set acquired on a GE Signa time-of-flight PET/MR in a similar way. The reconstructions of simulated and real 3D PET/MR data show that all priors were superior to post-smoothed maximum likelihood expectation maximization with ordered subsets (OSEM) in terms of bias-noise characteristics in different regions of interest where the PET uptake follows anatomical boundaries. Our implementation of the asymmetric Bowsher prior showed slightly superior performance compared with the two versions of PLS and the symmetric Bowsher prior. At very high regularization weights, all investigated anatomical priors suffer from the transfer of non-shared gradients.
Auteurs: Georg Schramm;Martin Holler;Ahmadreza Rezaei;Kathleen Vunckx;Florian Knoll;Kristian Bredies;Fernando Boada;Johan Nuyts;
Apparue dans: IEEE Transactions on Medical Imaging
Date publication: 02.-2018, volume: 37, issue:2, pages: 590 - 603
Editeur: IEEE
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» Evaluation of the Potential of Dipole Field Navigation for the Targeted Delivery of Therapeutic Agents in a Human Vascular Network
Résumé:
Magnetically guided agents in the vascular network are expected to enable the targeted delivery of therapeutics to localized regions while avoiding their systemic circulation. Due to the small size of the medically applicable superparamagnetic microscale agents required to reach the smaller arteries, high magnetic fields and gradients are required to reach saturation magnetization and generate sufficient directional forces, respectively, for their effective navigation in the vascular environment. Currently, the only method that provides both a high field and high magnetic gradient strengths in deep tissues at the human scale is known as dipole field navigation (DFN). This method relies on the controlled distortion of the field inside a magnetic resonance imaging scanner by precisely positioning ferromagnetic cores around the patient. This paper builds on previous works that have experimentally demonstrated the feasibility of the method and proposed optimization algorithms for placing the cores. The maximum gradient strengths that can be generated for single and multibifurcation vascular routes are investigated while considering the major constraints on core positions (limited space in the scanner, magnetic interactions). Using disc cores, which were previously shown particularly effective for the DFN, results show that gradient strengths exceeding 400 mT/m (a tenfold increase with respect to typical gradients generated by clinical MRI scanners) can be achieved at 10 cm inside the patient, but decrease as the complexity of the vascular route increases. The potential of the method is evaluated for targeting regions of a vascular model of a human liver, segmented from clinical data, with encouraging results showing strengths up to 150 mT/m for generating gradients at three consecutive bifurcations within 20° of average gradient direction error.
Auteurs: Maxime Latulippe;Sylvain Martel;
Apparue dans: IEEE Transactions on Magnetics
Date publication: 02.-2018, volume: 54, issue:2, pages: 1 - 12
Editeur: IEEE
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» Evaluation of the Role of Deep Trap State Using Analytical Model in the Program/Erase Cycling of NAND Flash Memory and Its Process Dependence
Résumé:
A method to analyze the kinetics of the charge accumulation in the tunnel oxide by the nand flash memory program and erase (P/E) cycling is proposed. Both electron trapping and detrapping processes are required to be considered owing to the oxide high electric field during P/E cycles. Consequently, the electron trapping in the deep trap state is concluded, whose trap energy ( $text{E}_{text {trap}}$ ) is more than 3.5 eV. Furthermore, the as-grown trap state density ( ${text{N}}_{e}$ ), the trapping capture cross section ( $sigma $ ), and the number of trapped positive charges can also be extracted to explain the tunneling current modulation and the $text{V}_{text {T}}$ shift by oxide-trapped charges under the P/E stress. The trapped electrons are mainly distributed in the center of tunnel oxide, and the distributed area extends as the P/E bias increases. In addition, the dependence of oxidation process is also shown. Both thermal dry and plasma oxidation have almost the same value of $sigma $ ( $sim {4} times {10}^{ {-17}}$ cm2). However, 30% reduction of ${text{N}}_{e}$ is shown in plasma oxidation ( $sim {1.25} times {10}^{ {19}}$ cm−3) when compared with thermal dry oxidation ( $sim {1.88} times {10}^{ {19}}$ cm−3).
Auteurs: Bo-Jun Yang;Yu-Ting Wu;Yung-Yueh Chiu;Tse-Mien Kuo;Jung-Ho Chang;Pin-Yao Wang;Riichiro Shirota;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 02.-2018, volume: 65, issue:2, pages: 499 - 506
Editeur: IEEE
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» Evaluations of a Class of Integrals That Arise in Wave Scattering Problems by Using the Taylor Product Theorem
Résumé:
Taylor product theorem is applied to the evaluation of a class of integrals that arise in high-frequency wave scattering problems. We expand a term $1/(t^{2}+1)$ under the integral into exponentiated powers of $t$ that are suitable for term-by-term integrations. We utilize the expansion in an example and make accuracy and speed analysis.
Auteurs: Ali Uzer;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 02.-2018, volume: 66, issue:2, pages: 1031 - 1034
Editeur: IEEE
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» Event-Based Model Predictive Tracking Control of Nonholonomic Systems With Coupled Input Constraint and Bounded Disturbances
Résumé:
This paper studies the event-based model predictive control (EMPC) for tracking of nonholonomic mobile robot with coupled input constraint and bounded disturbances. First, an event-triggering mechanism is presented by designing a threshold for the error between the actual trajectory and the predicted one, aiming at reducing the computational load. Second, a model predictive control strategy is developed based on the event-triggering mechanism. Recursive feasibility is guaranteed by designing a robust terminal region and the proper parameters. We show that the tracking system is practically stable and also provides a convergence region for the tracking error. The convergence region indicates that the tracking performance is negatively related to the minimal interevent time as well as the bound of the disturbances. Finally, simulation results show that the computation load is significantly reduced and illustrate the efficiency of our proposed strategy.
Auteurs: Zhongqi Sun;Li Dai;Yuanqing Xia;Kun Liu;
Apparue dans: IEEE Transactions on Automatic Control
Date publication: 02.-2018, volume: 63, issue:2, pages: 608 - 615
Editeur: IEEE
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» Event-Triggered Protocol for the Consensus of Multi-Agent Systems With State-Dependent Nonlinear Coupling
Résumé:
This paper proposes an event-triggered protocol to achieve consensus in multi-agent system, in which neighboring agents are coupled via a nonlinear function with local passivity. It is mathematically proved that the proposed protocol guarantees average consensus in the system, excluding the existence of Zeno phenomenon. As a practical application, the scheme is applied to achieve synchronization in the Kuramoto oscillator network. Phase agreement is obtained for oscillators with identical natural frequency. For oscillators with non-identical natural frequencies, their phases are confined in a bounded range and their frequencies reach an average of their natural frequencies. To further demonstrate the generality of the scheme, another multi-agent system with coupling based on exponential and tangent functions is also presented. All the simulation results verify the condition of consensus and confirm the effectiveness of the scheme.
Auteurs: Qiang Jia;Wallace K. S. Tang;
Apparue dans: IEEE Transactions on Circuits and Systems I: Regular Papers
Date publication: 02.-2018, volume: 65, issue:2, pages: 723 - 732
Editeur: IEEE
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» Evidence of Variabilities in EEG Dynamics During Motor Imagery-Based Multiclass Brain–Computer Interface
Résumé:
Inter-subject and inter-session variabilities pose a significant challenge in electroencephalogram (EEG)-based brain–computer interface (BCI) systems. Furthermore, high dimensional EEG montages introduce huge computational burden due to excessive number of channels involved. Two experimental, i.e., inter-session and inter-subject, variabilities of EEG dynamics during motor imagery (MI) tasks are investigated in this paper. In particular, the effect on the performance of the BCIs due to day-to-day variability in EEG dynamics during the alterations in cognitive stages is explored. In addition, the inter-subject BCIs feasibility between cortically synchronized and desynchronized subject pairs on pairwise performance associativity is further examined. Moreover, the consequences of integrating spatial brain dynamics of varying the number of channels - from specific regions of the brain - are also discussed in case of both the contexts. The proposed approach is validated on real BCI data set containing EEG data from four classes of MI tasks, i.e., left/right hand, both feet, and tongue, subjected prior to a preprocessing of three different spatial filtering techniques. Experimental results have shown that a maximum classification accuracy of around 58% was achieved for the inter-subject experimental case, whereas a 31% deviation was noticed in the classification accuracies across two sessions during the inter-session experimental case. In conclusion, BCIs, without the subject-and session-specific calibration and with lesser number of channels employed, play a vital role while promoting a generic and efficient framework for plug and play use.
Auteurs: Simanto Saha;Khawza Iftekhar Uddin Ahmed;Raqibul Mostafa;Leontios Hadjileontiadis;Ahsan Khandoker;
Apparue dans: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Date publication: 02.-2018, volume: 26, issue:2, pages: 371 - 382
Editeur: IEEE
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» Evolution of Global Product Development Networks: An Exploratory Study
Résumé:
Global Product Development (GPD) networks have evolved to satisfy the unique requirements essential to the successful adoption of corporate outsourcing and offshoring during development processes. Having reviewed the relevant literature associated with GPD, this paper seeks to contribute to the understanding of organizational considerations taken by GPD networks during their transitional processes. A retrospective case study analysis was conducted with 17 Italian companies classified into six GPD configurations (named the “Chess matrix”). Each classification was based on both developmental localization (local versus global) and product development process fragmentation; development activities are either entirely performed within the same development lab, eventually with the contribution of support/adaptive units, or they are split among development units. Using this classification system, an evolutionary model was adopted to illustrate the dynamic paths companies follow when transitioning toward new GPD configurations. With this framework and categorization process, it was deduced that three main variables drove each of the 17 companies: 1) market needs; 2) market extension; and 3) internal needs. These variables were determined based on the GPD approach each company adopted in pursuit of a stable profitable configuration that was achieved by either deliberately remaining in a certain configuration or by employing an evolutionary GPD development configuration. In recognizing that there is not a singularly optimal stable configuration, it is essential to recognize and identify the individual drivers being pursued by each enterprise when implementing specific configurations. Further research will be devoted to more extensively elaborate the paths within a larger sample of companies to identify unrevealed paths and drivers that move companies in their product development globalization efforts.
Auteurs: Margherita Pero;Monica Rossi;Sergio Terzi;
Apparue dans: IEEE Transactions on Engineering Management
Date publication: 02.-2018, volume: 65, issue:1, pages: 34 - 45
Editeur: IEEE
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» Evolutionary Stability of Reputation-Based Incentive Mechanisms in P2P Systems
Résumé:
Free riding is a severe problem in P2P systems. Although many incentive mechanisms based on reputation have been proposed to mitigate problem of free riding, reputation management fails to evolve as an evolutionary stable strategy (ESS) due to cost involved in keeping track of reputation. We prove that a system setting with one time entry fee, imposed on new comers and distributed among the peers that calculate reputation, makes reputation-based resource allocation an ESS. Then, we simulate the system model using evolutionary dynamics for its performance evaluation.
Auteurs: Antriksh Goswami;Gopal Sharan Parashari;Ruchir Gupta;
Apparue dans: IEEE Communications Letters
Date publication: 02.-2018, volume: 22, issue:2, pages: 268 - 271
Editeur: IEEE
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» Exact Bit Error Rate Analysis for Color Shift Keying Modulation
Résumé:
In this letter, we present a new method to derive the exact analytical expression for the bit error rate (BER) of the color shift keying (CSK) modulation scheme over additive white Gaussian noise channel. We first exploit the coplanarity of CSK symbols, and build up a 2-D graphically symmetric space to simplify the BER analysis in the 3-D space of the signal transmitted via the red, green, and blue light beams. Thanks to the graphical symmetry of the symbols in the 2-D space, the symbol transition probabilities can be evaluated with less complexity. Then, with the aid of decision region partitioning, the exact symbol transition probabilities can be calculated. At last, the exact BER can be obtained by the weighted sum of all the symbol transition probabilities with the corresponding Hamming distances. Simulations are performed, and the results demonstrate that our presented BER analysis achieves more exact performance evaluation in both high and low signal-to-noise ratio regimes than the counterparts in other papers.
Auteurs: Jian Tang;Lin Zhang;Zhiqiang Wu;
Apparue dans: IEEE Communications Letters
Date publication: 02.-2018, volume: 22, issue:2, pages: 284 - 287
Editeur: IEEE
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» Exact Calculation of Noise Maps and ${g}$ -Factor in GRAPPA Using a ${k}$ -Space Analysis
Résumé:
Characterization of the noise distribution in magnetic resonance images has multiple applications, including quality assurance and protocol optimization. Noise characterization is particularly important in the presence of parallel imaging acceleration with multi-coil acquisitions, where the noise distribution can contain severe spatial heterogeneities. If the parallel imaging reconstruction is a linear process, an accurate noise analysis can be carried out by taking into account the correlations between all the samples involved. However, for ${k}$ -space-based techniques such as generalized autocalibrating partially parallel acquisition (GRAPPA), the exact analysis has been considered computationally prohibitive due to the very large size of the noise covariance matrices required to characterize the noise propagation from ${k}$ -space to image space. Previously proposed methods avoid this computational burden by formulating the GRAPPA reconstruction as a pixel-wise linear operation performed in the image space. However, these methods are not exact in the presence of non-uniform sampling of ${k}$ -space (e.g., containing a calibration region). For this reason, in this paper, we develop an accurate characterization of the noise distribution for self-calibrated parallel imaging in the presence of arbitrary Cartesian sampling patterns. By exploiting the symmetries and separability in the noise propagation process, the proposed method is computationally efficient and does not require large matrices. Under the assumption of a fixed reconstruction kernel, this method provides the precise distribution of the noise variance for each coil’s image. These coil-by-coil noise maps are subsequently combined according to the coil combination approach- used in image reconstruction, and therefore can be applied with both complex coil combination and root-sum-of-squares approaches. In this paper, we present the proposed noise characterization method and compare it to previous techniques using Monte Carlo simulations as well as phantom acquisitions.
Auteurs: Iñaki Rabanillo;Santiago Aja-Fernández;Carlos Alberola-López;Diego Hernando;
Apparue dans: IEEE Transactions on Medical Imaging
Date publication: 02.-2018, volume: 37, issue:2, pages: 480 - 490
Editeur: IEEE
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» Examining the Impact of a Crude Oil Spill on the Permittivity Profile and Normalized Radar Cross Section of Young Sea Ice
Résumé:
An oil-in-sea ice mesocosm experiment was conducted at the University of Manitoba Sea-Ice Environmental Research Facility from January to March 2016 in which geophysical and electromagnetic parameters of the ice were measured, and general observations about the oil-contaminated ice were made. From the experimental measurements, the presence of crude oil appears to affect the temperature and bulk salinity profiles as well as the normalized radar cross section (NRCS) of the contaminated young sea ice. The measured temperature and bulk salinity profiles of the ice, as well as the crude oil distribution within the ice, were used to model the permittivity profile of the oil-contaminated ice by adapting two mixture models commonly used to describe sea ice to account for the presence of oil. Permittivity modeling results were used to simulate the NRCS of the oil-contaminated sea ice in an effort to determine the accuracy of the models. In addition, the application of X-ray microtomography in modeling the dielectric profile of oil-contaminated sea ice was examined. The sensitivity of the permittivity models for oil-contaminated sea ice to changes in temperature, frequency, and oil volume fraction was also examined.
Auteurs: Thomas D. Neusitzer;Nariman Firoozy;Tyler M. Tiede;Durell S. Desmond;Marcos J. L. Lemes;Gary A. Stern;Søren Rysgaard;Puyan Mojabi;David G. Barber;
Apparue dans: IEEE Transactions on Geoscience and Remote Sensing
Date publication: 02.-2018, volume: 56, issue:2, pages: 921 - 936
Editeur: IEEE
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» Exclusion of Linear Acceleration Signal in the MEMS Thermal Gyroscope
Résumé:
This letter identifies the source of linear acceleration signal in the microelectromechanical systems (MEMS) thermal gyroscope and provides a real-time solution to exclude it. The main culprit of the undesired acceleration signal is found to be lack of rotational symmetry due to Manhattan sensor topology. A higher level of symmetry is obtained by constructing a hybrid gyroscope using two individual devices operating in tandem but 180° out-of-phase. A precision rotary stage is used to test the duo. The experiments confirmed that higher symmetry is promising in excluding the acceleration signal. Compared with a single device, the hybrid gyroscope demonstrated 16-fold reduction in the acceleration signal and 5-fold improved acceleration to rotation sensitivities. [2017-0171]
Auteurs: Jamal Bahari;Carlo Menon;
Apparue dans: Journal of Microelectromechanical Systems
Date publication: 02.-2018, volume: 27, issue:1, pages: 19 - 21
Editeur: IEEE
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» Expanding-Window BATS Code for Scalable Video Multicasting Over Erasure Networks
Résumé:
In this paper we consider scalable video multicasting over erasure networks with heterogeneous video quality requirements. With random linear network coding (RLNC) applied at the intermediate nodes the information received by the destinations is determined by the associated channel rank distributions based on which we obtain the optimal achievable code rate at the source node. We show that although a concatenation of priority encoded transmission (PET) with RLNC achieves the optimal code rate it incurs prohibitive high coding complexity. On the other hand batched sparse (BATS) code has been recently proposed for unicast networks which has low coding complexity with near-optimal overhead. However the existing BATS code design cannot be applied for multicast networks with heterogeneous channel rank distributions at different destinations. To this end we propose a novel expanding window BATS (EW-BATS) code where the input symbols are grouped into overlapped windows according to their importance levels. The more important symbols are encoded with lower rate and hence they can be decoded by more destinations while the less important symbols are encoded with higher rate and are only decoded by the destinations with high throughput for video quality enhancement. Based on asymptotical performance analysis we formulate the linear optimization problems to jointly optimize the degree distributions for each window and the window selection probabilities. Simulation results show that the proposed EW-BATS code satisfies the decoding requirements with much lower transmission overhead compared with separate BATS code where the degree distributions are separately optimized for each destination.
Auteurs: Xiaoli Xu;Yong Zeng;Yong Liang Guan;Lei Yuan;
Apparue dans: IEEE Transactions on Multimedia
Date publication: 02.-2018, volume: 20, issue:2, pages: 271 - 281
Editeur: IEEE
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» Experience With Online Partial-Discharge Measurement in High-Voltage Inverter-Fed Motors
Résumé:
Partial-discharge (PD) testing has long been an important tool for assessing the condition of the high-voltage insulation in motor and generator stator windings. In the past several years, many motors have been powered from inverters, which facilitate variable-speed motor operation. The most common drive used today is the voltage-source pulse-width modulation (VS-PWM) type. VS-PWM drives rated up to 13.8 kV are becoming more common in natural gas processing plants, as well as in other petrochemical facilities. Such drives generate high-voltage impulses in the kilovolt range with rise times in the submicrosecond range. These impulses are a form of severe electrical interference that can make difficult the online detection of PD (with magnitudes 1000 times smaller) due to the overlapping frequency content in PD and in the impulses. Thus, PD detection on medium-voltage VS-PWM systems has been a challenge in spite of the serious stator winding insulation aging that such drives may cause to these motors. This paper discusses the stator winding failure mechanisms that produce PD, including the insulation problems that VS-PWM drives can accelerate. A research project that lasted several years is reviewed. This project culminated in a prototype online PD monitoring system suitable for motors fed by VS-PWM drives.
Auteurs: Greg C. Stone;Howard G. Sedding;Connor Chan;
Apparue dans: IEEE Transactions on Industry Applications
Date publication: 02.-2018, volume: 54, issue:1, pages: 866 - 872
Editeur: IEEE
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» Experiment for Radiation From Horizontal Loop Located on the Earth’s Surface
Résumé:
This paper develops a “ground-airborne” model for a horizontal large loop, proposes a novel noise cancellation technique, and conducts an experiment for verification. In the experiment, large horizontal loop located on the earth’s surface is employed as a source antenna to generate extremely low frequency magnetic fields. Using a potassium optically pumped magnetometer GSMP-35A suspended below the helicopter, the fields are recorded on three survey planes at different heights. Comparing the theoretical solution with experiments, the magnetic field envelopes are in good agreement with the theoretical solution and validity of the noise cancellation procedure is verified.
Auteurs: Xiaodong Qu;Feng Zhang;Guangyou Fang;
Apparue dans: IEEE Sensors Journal
Date publication: 02.-2018, volume: 18, issue:4, pages: 1628 - 1635
Editeur: IEEE
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» Experimental and Numerical Demonstration on the Gain and Power Saturation of Yb-Doped Double-Clad Fiber Amplifiers in Multiwavelength CW and Ultrafast Pulsed Operation
Résumé:
Experimental studies on gain and saturation of a Yb-doped double-cladding fiber amplifier accompanied with and interpreted by rigorous numerical simulations are presented. The saturation power, the value, and the spectral asymmetry of the output signal are experimentally characterized in both pulsed and continuous wave (CW) operation, and then, verified and interpreted numerically. Power conversion efficiency and quantum conversion efficiency of the amplifier are measured to be up to 55% and 58%, respectively. It is the first time, to the best of our knowledge, to demonstrate a numerical model for the pulsed operation based on the interaction of vector coupled nonlinear Schrodinger equations and the rate equations of the Yb-doped double-clad fiber taking into account all high-order dispersion parameters and the variation of gain coefficient during pulse propagation. A good agreement between numerical and experimental results is observed providing interpretations to the results. The numerical models and the experimental demonstrations provide guidance for the design and analysis of Yb-doped double-cladding fiber amplifiers both in pulsed and CW operation.
Auteurs: Mohamed A. Abdelalim;Hussein E. Kotb;Ebin Joseph;Ahmed M. Othman;Hanan Anis;
Apparue dans: IEEE Photonics Journal
Date publication: 02.-2018, volume: 10, issue:1, pages: 1 - 12
Editeur: IEEE
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» Experimental Characterization of the Inline-Screw-Feeding Vacuum-Arc-Thruster Operation
Résumé:
A CubeSat-class micropropulsion system is being developed at the Aerospace Plasma Laboratory, Technion-Israel Institute of Technology, called the inline-screw-feeding vacuum-arc thruster (ISF-VAT). The ISF-VAT couples a conventional VAT triggerless ignition geometry with an active feeding system that mechanically drives the cathode propellant in a periodic helical motion. The thruster performance is found to be highly regular for at least 700 000 pulses, $approx 12$ h of continuous operation, with good pulse to pulse repeatability. The measured average thrust-to-power ratio is $approx 3~mu text{N}$ /W. Observations of the cathode and insulator erosion patterns show that while the cathode electrode geometry is maintained by the feeding system, the ceramic insulator is also being consumed. The maximum insulator erosion rate was determined to be $approx 1$ /7 of the cathode consumption rate. The thruster lifetime is, therefore, determined by the length of the insulator.
Auteurs: Igal Kronhaus;Matteo Laterza;Alexander R. Linossier;
Apparue dans: IEEE Transactions on Plasma Science
Date publication: 02.-2018, volume: 46, issue:2, pages: 283 - 288
Editeur: IEEE
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» Experimental Time Evolution Study of the HfO2-Based IMPLY Gate Operation
Résumé:
In the last years, memristor devices have been proposed as key elements to develop a new paradigm to implement logic gates. In particular, the memristor-based material implication (IMPLY) gate has been presented as a potential powerful basis for logic applications. In the literature, the IMPLY operation has been widely simulated, but most of the efforts have been just focused on accomplishing its truth table, only considering the initial and final states of the gate. However, a complete understanding of the time evolution between states is still missing and barely reported yet. In this paper, the time evolution of the memristors involved in an IMPLY gate are studied in detail for every case of the gate. Furthermore, the impact on IMPLY gate operation of the internal resistor connected in series with the memristors of the IMPLY gate is included.
Auteurs: Marcos Maestro-Izquierdo;Javier Martin-Martinez;Albert Crespo Yepes;Manel Escudero;Rosana Rodríguez;Montserrat Nafría;Xavier Aymerich;Antonio Rubio;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 02.-2018, volume: 65, issue:2, pages: 404 - 410
Editeur: IEEE
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» Experimental Validation of Dual H-Bridge Current Flow Controllers for Meshed HVdc Grids
Résumé:
The current-carrying capability of dc lines is limited by their thermal and electric stress limits. Thus, the line current must be maintained within the permissible operational region to protect the lines from damage. In a dense dc grid, control over each line current cannot be achieved without including additional control devices. In this paper, a dual H-bridge current flow controller (2B-CFC) is used to manage the dc grid line power flow by providing dc voltage compensation in series with dc lines. A centralized hierarchical control system is proposed to coordinate the operation between multiple CFCs. A novel voltage-sharing control scheme is demonstrated. It is shown that such a scheme reduces the workload on a single CFC by sharing the required control voltage between multiple CFCs, and, in addition, can be used to avoid control conflicts among active CFCs during communication failure. An experimental platform consisting of a three-terminal dc grid and small-scale 2B-CFC prototypes has been developed to validate the concepts. For completeness, the CFC performance has been analyzed for overload conditions and when no communication exists. Small-scale dc circuit breakers have been developed to study the CFC performance under a pole-to-pole fault.
Auteurs: Senthooran Balasubramaniam;Carlos E. Ugalde-Loo;Jun Liang;Tibin Joseph;Rose King;Andrzej Adamczyk;
Apparue dans: IEEE Transactions on Power Delivery
Date publication: 02.-2018, volume: 33, issue:1, pages: 381 - 392
Editeur: IEEE
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» Explicit Edge Inconsistency Evaluation Model for Color-Guided Depth Map Enhancement
Résumé:
Color-guided depth enhancement is used to refine depth maps according to the assumption that the depth edges and the color edges at the corresponding locations are consistent. In methods on such low-level vision tasks, the Markov random field (MRF), including its variants, is one of the major approaches that have dominated this area for several years. However, the assumption above is not always true. To tackle the problem, the state-of-the-art solutions are to adjust the weighting coefficient inside the smoothness term of the MRF model. These methods lack an explicit evaluation model to quantitatively measure the inconsistency between the depth edge map and the color edge map, so they cannot adaptively control the efforts of the guidance from the color image for depth enhancement, leading to various defects such as texture-copy artifacts and blurring depth edges. In this paper, we propose a quantitative measurement on such inconsistency and explicitly embed it into the smoothness term. The proposed method demonstrates promising experimental results compared with the benchmark and state-of-the-art methods on the Middlebury ToF-Mark, and NYU data sets.
Auteurs: Yifan Zuo;Qiang Wu;Jian Zhang;Ping An;
Apparue dans: IEEE Transactions on Circuits and Systems for Video Technology
Date publication: 02.-2018, volume: 28, issue:2, pages: 439 - 453
Editeur: IEEE
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» Exploiting Elastic Energy Storage for “Blind” Cyclic Manipulation: Modeling, Stability Analysis, Control, and Experiments for Dribbling
Résumé:
For creating robots that are capable of human-like performance in terms of speed, energetic properties, and robustness, intrinsic compliance is a promising design element. In this paper, we investigate the principle effects of elastic energy storage and release for basketball dribbling in terms of open-loop cycle stability. We base the analysis, which is performed for the 1-degree-of-freedom (DoF) case, on error propagation, peak power performance during hand contact, and robustness with respect to varying hand stiffness. As the ball can only be controlled during contact, an intrinsically elastic hand extends the contact time and improves the energetic characteristics of the process. To back up our basic insights, we extend the 1-DoF controller to 6-DoFs and show how passive compliance can be exploited for a 6-DoF cyclic ball dribbling task with a 7-DoF articulated Cartesian impedance controlled robot. As a human is able to dribble blindly, we decided to focus on the case of contact force sensing only, i.e., no visual information is necessary in our approach. We show via simulation and experiment that it is possible to achieve a stable dynamic cycle based on the 1-DoF analysis for the primary vertical axis together with control strategies for the secondary translations and rotations of the task. The scheme allows also the continuous tracking of a desired dribbling height and horizontal position. The approach is also used to hypothesize about human dribbling and is validated with captured data.
Auteurs: Sami Haddadin;Kai Krieger;Alin Albu-Schäffer;Torsten Lilge;
Apparue dans: IEEE Transactions on Robotics
Date publication: 02.-2018, volume: 34, issue:1, pages: 91 - 112
Editeur: IEEE
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» Exploiting Feature and Class Relationships in Video Categorization with Regularized Deep Neural Networks
Résumé:
In this paper, we study the challenging problem of categorizing videos according to high-level semantics such as the existence of a particular human action or a complex event. Although extensive efforts have been devoted in recent years, most existing works combined multiple video features using simple fusion strategies and neglected the utilization of inter-class semantic relationships. This paper proposes a novel unified framework that jointly exploits the feature relationships and the class relationships for improved categorization performance. Specifically, these two types of relationships are estimated and utilized by imposing regularizations in the learning process of a deep neural network (DNN). Through arming the DNN with better capability of harnessing both the feature and the class relationships, the proposed regularized DNN (rDNN) is more suitable for modeling video semantics. We show that rDNN produces better performance over several state-of-the-art approaches. Competitive results are reported on the well-known Hollywood2 and Columbia Consumer Video benchmarks. In addition, to stimulate future research on large scale video categorization, we collect and release a new benchmark dataset, called FCVID, which contains 91,223 Internet videos and 239 manually annotated categories.
Auteurs: Yu-Gang Jiang;Zuxuan Wu;Jun Wang;Xiangyang Xue;Shih-Fu Chang;
Apparue dans: IEEE Transactions on Pattern Analysis and Machine Intelligence
Date publication: 02.-2018, volume: 40, issue:2, pages: 352 - 364
Editeur: IEEE
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» Exploring 3-D Printing for New Applications: Novel Inkjet- and 3-D-Printed Millimeter-Wave Components, Interconnects, and Systems
Résumé:
This article outlines a number of inkjet-/three-dimensional (3-D)-printed prototypes of RF and millimeter-wave (mmW) components, interconnects, and systems. We pay special attention to the major challenges related to applying current multidimensional printing technologies to the fabrication of flexible multichip modules (MCMs) and high-performance mmW components.
Auteurs: Ryan Bahr;Bijan Tehrani;Manos M. Tentzeris;
Apparue dans: IEEE Microwave Magazine
Date publication: 02.-2018, volume: 19, issue:1, pages: 57 - 66
Editeur: IEEE
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» Exploring Hybrid STT-MTJ/CMOS Energy Solution in Near-/Sub-Threshold Regime for IoT Applications
Résumé:
Emerging memories have been developed to achieve energy efficiency target in the Internet of Things era. Spin transfer torque magnetic tunnel junction (STT-MTJ)-based nonvolatile (NV) memory has demonstrated attractive performance because of zero standby power, reduced switching power, infinite endurance, and high density. Meanwhile, hybrid STT-MTJ/CMOS integration is a promising solution to overcome the bottleneck of dynamic and leakage power dissipation. In this paper, ultralow power methodologies are developed at device and circuit level in 28 nm fully depleted silicon on insulator CMOS technology. Supply voltage scaling, near-/sub-threshold ( $V_{t}$ ) operation, and back-bias adjustment are demonstrated, showing 81% dynamic power reduction under 0.6 V near- $V_{t}$ sensing operation, with the tradeoff of 6.2% increased sensing error rate. Through the case study on STT-MTJ-based NV flip-flops (NV-FFs), up to 76% dynamic and 79% leakage power saving can be realized in ultra-low power NV-FF implementation.
Auteurs: Hao Cai;You Wang;Lirida Alves de Barros Naviner;Jun Yang;Weisheng Zhao;
Apparue dans: IEEE Transactions on Magnetics
Date publication: 02.-2018, volume: 54, issue:2, pages: 1 - 9
Editeur: IEEE
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» Exploring the Tuning Range of Channel Filters for Satellite Applications Using Electromagnetic-Based Computer Aided Design Tools
Résumé:
The objective of this paper is to use electromagnetic-based computer-aided design (CAD) tools to investigate the maximum tuning range of channel filters, typically used in satellite payloads. Both circular and rectangular waveguide technologies are investigated. The results of the investigation show that single-mode rectangular waveguide implementations offer substantially wider tuning range, as opposed to classical dual-mode circular waveguide implementations. In addition to simulations, measurements are also presented indicating very good agreement with theory, thereby fully validating the CAD procedure.
Auteurs: Javier Ossorio;Joaquin Vague;Vicente E. Boria;Marco Guglielmi;
Apparue dans: IEEE Transactions on Microwave Theory and Techniques
Date publication: 02.-2018, volume: 66, issue:2, pages: 717 - 725
Editeur: IEEE
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» Exploring Triangle-Free Dense Structures
Résumé:
Triadic closure is ubiquitous in social networks, which refers to the property among three individuals, A, B, and C, such that if there exist strong ties between A-B and A-C, then there must be a strong or weak tie between B-C. Related to triadic closure, the number of triangles has been extensively studied since it can be effectively used as a metric to analyze the structure and function of a network. In this paper, from a different viewpoint, we study triangle-free dense structures which have received little attention. We focus on $K_{3,3}$ where there are two subsets of three vertices, a vertex in a subset has an edge connected to every vertex in another subset while it does not have an edge to any other vertex in the same subset. Such $K_{n,n}$ in general implies a philosophy contradiction: (a) Any two individuals are friends if they have no common friends, and (b) Any two individuals are not friends if they have common friends. However, we find such induced $K_{3,3}$ does exist frequently, and they do not disappear over time over a real academic collaboration network. In addition, in the real datasets tested, nearly all edges appearing in $K_{3,3}$ appear in some triangles. We analyze the expected numbers of induced $K_{3,3}$ and triangles ( $Delta$ ) in four representative random graph models, namely, Erdős-Rényi random graph model, Watts-Strogatz small-world model, Barabási-Albert preferential attachment model, and configuration model, and give an algorithm to enumerate all distinct $K_{3,3}$ in an undirected social network. We conduct extensive experiments on both real and synthetic datasets to confirm our findings. As an application, such $K_{3,3}$ found helps to find new stars collaborated by well-known figures who themselves do not collaborate.
Auteurs: Can Lu;Jeffrey Xu Yu;Hao Wei;
Apparue dans: IEEE Transactions on Knowledge and Data Engineering
Date publication: 02.-2018, volume: 30, issue:2, pages: 278 - 291
Editeur: IEEE
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» Explosion Protection of a Motor Integrated With a Compressor Using a Purging and Pressurization Technique With a Flammable Gas Above the UFL
Résumé:
This paper describes construction and test methods developed for a high-speed induction motor integrated with a compressor using the explosion protection technique of purged and pressurized by flammable gas, which is maintained above the upper flammable limit (UFL) after purging the system of air. The National Electrical Code [NEC or national fire protection agency (NFPA) 70 [1]] permits motors to be submerged in a flammable gas or vapor that is at a pressure greater than atmospheric pressure, and that is flammable only when mixed with air as the explosion protection means. Purging and pressurizing of electrical equipment with air or inert gas to the requirements of NFPA 496 [2] is widely known, but those requirements do not apply to a motor designed to be immersed in a flammable fluid. Specific requirements were developed for a high-speed induction motor–compressor supplied by a variable frequency power supply. This motor is directly connected to a natural gas or hydrocarbon mixture compressor, and the system is purged and pressurized with flammable gas that is maintained above the UFL and pressurized above atmospheric pressure. Though the NEC [1] has permitted this protection concept for many years, a set of construction and testing requirements needed to be developed and published for certification purposes. These types of motors have been operating safely in Europe and in North America for many years with a similar concept for the protection technique. This paper will discuss using the flammable gas above the UFL protection technique, and the development of the construction and testing requirements for it.
Auteurs: Bharat Mistry;Donald W. Ankele;Roberto Baldocci;Emilie Ourion;
Apparue dans: IEEE Transactions on Industry Applications
Date publication: 02.-2018, volume: 54, issue:1, pages: 883 - 888
Editeur: IEEE
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» Exponential Pointwise Stabilization of Semilinear Parabolic Distributed Parameter Systems via the Takagi–Sugeno Fuzzy PDE Model
Résumé:
This paper deals with the problem of exponential stabilization for nonlinear parabolic distributed parameter systems using the Takagi–Sugeno (T–S) fuzzy partial differential equation (PDE) model, where a finite number of actuators are active only at some specified points of the spatial domain (these actuators are referred to as pointwise actuators). Three cases of state feedback are respectively considered in this study as follows: full state feedback, piecewise state feedback, and collocated pointwise state feedback. It is initially assumed that a T–S fuzzy PDE model obtained via the sector nonlinearity approach is employed to accurately represent the semilinear parabolic PDE system. Based on the obtained T–S fuzzy PDE model, Lyapunov-based design methodologies of fuzzy feedback control laws are subsequently derived for the above three state feedback cases by using the vector-valued Wirtinger's inequality to guarantee locally exponential pointwise stabilization of the semilinear PDE system, and presented in terms of standard linear matrix inequalities (LMIs). Moreover, the favorable property offered by sharing all the same premises in the T–S fuzzy PDE models and fuzzy controllers is not applicable for the case of collocated pointwise state feedback. A parameterized LMI is introduced for this case to enhance the stabilization ability of the fuzzy controller. Finally, the merit and effectiveness of the proposed design methods are demonstrated by numerical simulation results of two examples.
Auteurs: Jun-Wei Wang;Huai-Ning Wu;
Apparue dans: IEEE Transactions on Fuzzy Systems
Date publication: 02.-2018, volume: 26, issue:1, pages: 155 - 173
Editeur: IEEE
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» Expression-Invariant Age Estimation Using Structured Learning
Résumé:
In this paper, we investigate and exploit the influence of facial expressions on automatic age estimation. Different from existing approaches, our method jointly learns the age and expression by introducing a new graphical model with a latent layer between the age/expression labels and the features. This layer aims to learn the relationship between the age and expression and captures the face changes which induce the aging and expression appearance, and thus obtaining expression-invariant age estimation. Conducted on three age-expression datasets (FACES [1] , Lifespan [2] and NEMO [3] ), our experiments illustrate the improvement in performance when the age is jointly learnt with expression in comparison to expression-independent age estimation. The age estimation error is reduced by 14.43, 37.75 and 9.30 percent for the FACES, Lifespan and NEMO datasets respectively. The results obtained by our graphical model, without prior-knowledge of the expressions of the tested faces, are better than the best reported ones for all datasets. The flexibility of the proposed model to include more cues is explored by incorporating gender together with age and expression. The results show performance improvements for all cues.
Auteurs: Zhongyu Lou;Fares Alnajar;Jose M. Alvarez;Ninghang Hu;Theo Gevers;
Apparue dans: IEEE Transactions on Pattern Analysis and Machine Intelligence
Date publication: 02.-2018, volume: 40, issue:2, pages: 365 - 375
Editeur: IEEE
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» Extended Random Walker for Shadow Detection in Very High Resolution Remote Sensing Images
Résumé:
The existence of shadows in very high resolution satellite images obstructs image interpretation and the following applications, such as target detection and recognition. Traditional shadow detection methods consider only the pixel-level properties, such as color and intensity of image pixels, and thus, may produce errors around object boundaries. To overcome this problem, a novel shadow detection algorithm based on extended random walker (ERW) is proposed by jointly integrating both shadow property and spatial correlations among adjacent pixels. First, a set of training samples is automatically generated via an improved Otsu-based thresholding method. Then, the support vector machine is applied to obtain an initial detection map, which categorizes all the pixels in the scene into shadow and nonshadow. Finally, the initial detection map is refined with the ERW model, which can simultaneously characterize the shadow property and spatial information in satellite images to further improve shadow detection accuracy. Experiments performed on five real remote sensing images demonstrate the superiority of the proposed method over several state-of-the-art methods in terms of detection accuracy.
Auteurs: Xudong Kang;Yufan Huang;Shutao Li;Hui Lin;Jon Atli Benediktsson;
Apparue dans: IEEE Transactions on Geoscience and Remote Sensing
Date publication: 02.-2018, volume: 56, issue:2, pages: 867 - 876
Editeur: IEEE
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» Extending 3-bit Burst Error-Correction Codes With Quadruple Adjacent Error Correction
Résumé:
The use of error-correction codes (ECCs) with advanced correction capability is a common system-level strategy to harden the memory against multiple bit upsets (MBUs). Therefore, the construction of ECCs with advanced error correction and low redundancy has become an important problem, especially for adjacent ECCs. Existing codes for mitigating MBUs mainly focus on the correction of up to 3-bit burst errors. As the technology scales and cell interval distance decrease, the number of affected bits can easily extend to more than 3 bit. The previous methods are therefore not enough to satisfy the reliability requirement of the applications in harsh environments. In this paper, a technique to extend 3-bit burst error-correction (BEC) codes with quadruple adjacent error correction (QAEC) is presented. First, the design rules are specified and then a searching algorithm is developed to find the codes that comply with those rules. The ${H}$ matrices of the 3-bit BEC with QAEC obtained are presented. They do not require additional parity check bits compared with a 3-bit BEC code. By applying the new algorithm to previous 3-bit BEC codes, the performance of 3-bit BEC is also remarkably improved. The encoding and decoding procedure of the proposed codes is illustrated with an example. Then, the encoders and decoders are implemented using a 65-nm library and the results show that our codes have moderate total area and delay overhead to achieve the correction ability extension.
Auteurs: Jiaqiang Li;Pedro Reviriego;Liyi Xiao;Costas Argyrides;Jie Li;
Apparue dans: IEEE Transactions on Very Large Scale Integration Systems
Date publication: 02.-2018, volume: 26, issue:2, pages: 221 - 229
Editeur: IEEE
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» Extension of NVNA Baseband Measurement for PA Characterization Under Complex Modulation
Résumé:
We investigated the measurement techniques of the nonlinear vector network analyzer (NVNA) test bench, to fully characterize the nonlinear behavior of radio frequency (RF) power amplifiers (PAs) driven by complex modulated signals. In order to extend the baseband measurements, two kinds of NVNA phase reference approaches are developed as alternative solutions, so that the baseband phase measurements can be achieved with those of modulated components at multiharmonic RF bands. In the first approach, a modulated baseband signal is combined with another modulated RF one to become the desired NVNA phase reference. While as an alternative solution, the second phase reference design is based on a “stepped” multisine, which is stepped through the baseband and each harmonic following the NVNA swept measurements, to achieve stable phase measurements. To validate these proposed NVNA test bench designs, an RF PA, driven by a large-signal long-term evolution-like multisine, was tested and compared with digital real-time oscilloscope measurements.
Auteurs: Yichi Zhang;Xiaotao Guo;Zhao He;David A. Humphreys;Lifeng Wang;Wei Zhao;Zilong Zhang;
Apparue dans: IEEE Transactions on Microwave Theory and Techniques
Date publication: 02.-2018, volume: 66, issue:2, pages: 1131 - 1141
Editeur: IEEE
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» Extracting and Defining Flexibility of Residential Electrical Vehicle Charging Loads
Résumé:
The popularization of electric vehicles raises concerns about their negative impact on the electrical grid. Extracting electric vehicle charging load patterns is a key factor that allows smart grid operators to make intelligent and informed decisions about conserving energy and promoting the stability of the electrical grid. This paper presents an unsupervised algorithm to extract electric vehicle charging load patterns nonintrusively from the smart meter data. Furthermore, a method to define flexibility for the collective electric vehicle charging demand by analyzing the time-variable patterns of the aggregated electric vehicle charging behaviors is presented. Validation results on real residential loads have shown that the proposed approach is a promising solution to extract electric vehicle charging loads and that the approach can effectively mitigate the interference of other appliances that have similar load behaviors as electric vehicles. Furthermore, a case study on real residential data to analyze electric vehicle charging trends and quantify the flexibility achievable from the aggregated electric vehicle load in different time periods is presented.
Auteurs: Amr A. Munshi;Yasser Abdel-Rady I. Mohamed;
Apparue dans: IEEE Transactions on Industrial Informatics
Date publication: 02.-2018, volume: 14, issue:2, pages: 448 - 461
Editeur: IEEE
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» F-DES: Fast and Deep Event Summarization
Résumé:
In the multimedia era a large volume of video data can be recorded during a certain period of time by multiple cameras. Such a rapid growth of video data requires both effective and efficient multiview video summarization techniques. The users can quickly browse and comprehend a large amount of audiovisual data. It is very difficult in real-time to manage and access the huge amount of video-content-handling issues of interview dependencies significant variations in illumination and presence of many unimportant frames with low activity. In this paper we propose a local-alignment-based FASTA approach to summarize the events in multiview videos as a solution of the aforementioned problems. A deep learning framework is used to extract the features to resolve the problem of variations in illumination and to remove fine texture details and detect the objects in a frame. Interview dependencies among multiple views of video are then captured via the FASTA algorithm through local alignment. Finally object tracking is applied to extract the frames with low activity. Subjective as well as objective evaluations clearly indicate the effectiveness of the proposed approach. Experiments show that the proposed summarization method successfully reduces the video content while keeping momentous information in the form of events. A computing analysis of the system also shows that it meets the requirement of real-time applications.
Auteurs: Krishan Kumar;Deepti D. Shrimankar;
Apparue dans: IEEE Transactions on Multimedia
Date publication: 02.-2018, volume: 20, issue:2, pages: 323 - 334
Editeur: IEEE
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» Face-Centered Anisotropic Surface Impedance Boundary Conditions in FDTD
Résumé:
Thin-sheet models are essential to allow shielding effectiveness of composite enclosures and vehicles to be modeled. Thin dispersive sheets are often modeled using surface-impedance models in finite-difference time-domain (FDTD) codes in order to deal efficiently with the multiscale nature of the overall structure. Such boundary conditions must be applied to collocated tangential electric and magnetic fields on either side of the surface; this is usually done on the edges of the FDTD mesh cells at the electric field sampling points. However, these edge-based schemes are difficult to implement accurately on stair-cased surfaces. Here, we present a novel face-centered approach to the collocation of the fields for the application of the boundary condition. This approach naturally deals with the ambiguities in the surface normal that arise at the edges on stair-cased surfaces, allowing a simpler implementation. The accuracy of the new scheme is compared to edge-based and conformal approaches using both planar sheet and spherical shell canonical test cases. Staircasing effects are quantified and the new face-centered scheme is shown have up to 3-dB lower error than the edge-based approach in the cases considered, without the complexity and computational cost of conformal techniques.
Auteurs: Ian D. Flintoft;Samuel A. Bourke;John F. Dawson;Jesus Alvarez;Miguel Ruiz Cabello;Martin P. Robinson;Salvador G. Garcia;
Apparue dans: IEEE Transactions on Microwave Theory and Techniques
Date publication: 02.-2018, volume: 66, issue:2, pages: 643 - 650
Editeur: IEEE
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» Facile Room Temperature Routes to Improve Performance of IGZO Thin-Film Transistors by an Ultrathin Al2O3 Passivation Layer
Résumé:
Although oxide thin-film transistors (TFTs) have drawn great interests in flexible displays, a key obstacle is the requirement of high-temperature annealing to realized mobility>10 cm $^{2}/text {V}cdot text {s}$ . In this paper, a fully room-temperature strategy, involving the deposition of ~10 nm In–Ga–Zn–O (IGZO) channel layer and ~4 nm Al2O3 passivation layer, is introduced. The as-prepared flexible TFT on polymide substrate exhibits a saturation mobility of 15.3 cm $^{2}/text {V}cdot text {s}$ , $V_{{text {th}}}$ of 3.08 V, and on/off current ratio of $2.3times 10^{{text {7}}}$ . Thickness-dependent analysis indicates that the interface between Al2O3 and IGZO is composed of negative O-rich layer, which impel the energy band bending inside the IGZO layers and release of electrons from traps. This paper opens up a route to achieve fully room-temperature fabrication of high-performance flexible TFT.
Auteurs: Honglong Ning;Yong Zeng;Zeke Zheng;Hongke Zhang;Zhiqiang Fang;Rihui Yao;Shiben Hu;Xiaoqing Li;Junbiao Peng;Weiguang Xie;Xubing Lu;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 02.-2018, volume: 65, issue:2, pages: 537 - 541
Editeur: IEEE
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» Factor Graph-Based Equalization for Two-Way Relaying With General Multi-Carrier Transmissions
Résumé:
Multi-carrier transmission schemes with general non-orthogonal waveforms provide a flexible time-frequency resource allocation and are bandwidth efficient. However, the interference inherently introduced by the non-orthogonal waveforms always requires a higher order equalizer at the receiver. Depending on the localization properties of the applied waveform, the structure and the complexity of this equalizer is adapted to consider channel influences, like carrier frequency and timing offsets. Especially for two-phase two-way relaying channels (TWRCs), where two users simultaneously transmit data on the same resources, a robust transmission scheme in presence of practical constraints such as asynchronicity is of utmost importance. This paper focuses on the utilization of general multi-carrier transmission schemes applied to TWRCs and the utilization of factor graph-based equalizers (FGEs) at the relay in order to mitigate the impacts of the physical channels, offsets, and the non-orthogonal waveforms. In combination with the subsequent physical-layer network coding detection/decoding scheme, this combination allows for a flexible design of the waveforms and the FGE to meet the complexity-performance trade-off at the relay. As demonstrated by numerical evaluation results, the proposed multi-carrier scheme with well-localized waveforms utilizing FGEs outperforms orthogonal frequency division multiplexing in TWRC for a wide range of practical impacts.
Auteurs: Matthias Woltering;Dirk Wübben;Armin Dekorsy;
Apparue dans: IEEE Transactions on Wireless Communications
Date publication: 02.-2018, volume: 17, issue:2, pages: 1212 - 1225
Editeur: IEEE
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» Fair Resource Allocation for Data-Intensive Computing in the Cloud
Résumé:
To address the computing challenge of ‘big data’, a number of data-intensive computing frameworks (e.g., MapReduce, Dryad, Storm and Spark) have emerged and become popular. YARN is a de facto resource management platform that enables these frameworks running together in a shared system. However, we observe that, in cloud computing environment, the fair resource allocation policy implemented in YARN is not suitable because of its memoryless resource allocation fashion leading to violations of a number of good properties in shared computing systems. This paper attempts to address these problems for YARN. Both single-level and hierarchical resource allocations are considered. For single-level resource allocation, we propose a novel fair resource allocation mechanism called Long-Term Resource Fairness (LTRF) for such computing. For hierarchical resource allocation, we propose Hierarchical Long-Term Resource Fairness (H-LTRF) by extending LTRF. We show that both LTRF and H-LTRF can address these fairness problems of current resource allocation policy and are thus suitable for cloud computing. Finally, we have developed LTYARN by implementing LTRF and H-LTRF in YARN, and our experiments show that it leads to a better resource fairness than existing fair schedulers of YARN.
Auteurs: Shanjiang Tang;Bu-Sung Lee;Bingsheng He;
Apparue dans: IEEE Transactions on Services Computing
Date publication: 02.-2018, volume: 11, issue:1, pages: 20 - 33
Editeur: IEEE
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» Fall Detection Using Deep Learning in Range-Doppler Radars
Résumé:
In this paper, we propose an approach that uses deep learning to detect a human fall. The proposed approach automatically captures the intricate properties of the radar returns. In order to minimize false alarms, we fuse information from both the time-frequency and range domains. Experimental data is used to demonstrate the superiority of the deep learning based approach in comparison with the principal component analysis method and those methods incorporating predefined physically interpreted features.
Auteurs: Branka Jokanović;Moeness Amin;
Apparue dans: IEEE Transactions on Aerospace and Electronic Systems
Date publication: 02.-2018, volume: 54, issue:1, pages: 180 - 189
Editeur: IEEE
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» Far-Field Sub-Wavelength Imaging of Two-Dimensional Extended Target Aided By Compact Planar Resonant Structures
Résumé:
Two kinds of compact planar electrical resonant structures (PERSs) are proposed as the solution to realize far-field sub-wavelength imaging of extended target. The proposed structures have their advantages in low profile, compact size, and electrical coupling property. The conversion between evanescent and propagation waves of the two structures enables the sub-wavelength information to be carried to far-field. The first PERS consists of periodically distributed spiral resonators. With the help of background Green's function, sub-wavelength images of two-dimensional extended target with the resolutions of λ/11 from simulation and λ/7 from experiment are reconstructed in the far-field by multiple signal classification imaging method. The second PERS similarly consists of spiral resonators, which operate at different frequencies. Image of an extended target with a resolution of λ/17 from experiment is reconstructed from the spectra received in the far-field, without the use of the background Green's function. Both simulations and experiments are performed to validate the proposed structures. The sub-wavelength imaging results show that the proposed PERSs can be widely applied in new super-resolution imaging systems.
Auteurs: Qiang Gao;Xiao-Hua Wang;Bing-Zhong Wang;
Apparue dans: IEEE Photonics Journal
Date publication: 02.-2018, volume: 10, issue:1, pages: 1 - 11
Editeur: IEEE
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» Faraday Rotation Correction for SMAP and Soil Moisture Retrieval
Résumé:
Faraday rotation can be significant at L-band and needs to be considered in remote sensing from space using the spectrum window at 1.413 GHz protected for passive observations. This is especially so for a conical scanner such as SMAP because the variation of the rotation angle with position around the scan is of the same order of magnitude as the change with geographic position as the sensor travels in its orbit around the globe. Furthermore, the angle retrieved in situ by the radiometer is particularly noisy over land raising additional issues for remote sensing of soil moisture. Research is reported here assessing the magnitude of the problem and suggesting an approach for treating Faraday rotation in the context of remote sensing of soil moisture with a conical scanner like SMAP.
Auteurs: David M. Le Vine;Saji Abraham;
Apparue dans: IEEE Transactions on Geoscience and Remote Sensing
Date publication: 02.-2018, volume: 56, issue:2, pages: 655 - 668
Editeur: IEEE
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» Fast Analysis of Time Interval Error in Current-Mode Drivers
Résumé:
An efficient approach for modeling of time interval error (TIE) due to noise in power delivery networks (PDNs), for current-mode (CM) driver circuits, is presented. Semianalytical expressions relating the PDN noise and TIE are developed based on midpoint delays of the rising and falling edges of the differential signal. The validating examples with CM driver circuits designed in various technologies comparing both the proposed and conventional approaches demonstrate a significant speedup using the proposed approach.
Auteurs: Jai Narayan Tripathi;Ramachandra Achar;Rakesh Malik;
Apparue dans: IEEE Transactions on Very Large Scale Integration Systems
Date publication: 02.-2018, volume: 26, issue:2, pages: 367 - 377
Editeur: IEEE
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» Fast Decoding of Expander Codes
Résumé:
Expander codes are Tanner codes defined on sparse graphs that have good expansion properties. Sipser and Spielman (1996) showed that there is a linear-time decoding algorithm for expander codes when the vertex expansion is at least 3/4 and the number of errors corrected is a constant fraction of the code length. Later, Feldman et al. (2007) gave a decoding algorithm that allows the expansion to be 2/3 + 1/(3c), where $c$ is the left degree of the underlying bipartite graph, at the expense of polynomial-time decoding complexity. Recently, Viderman (2013) further improved the expansion parameter to $2/3 - 1/(6c)$ , and the decoding algorithm runs in linear time. These results are for expander codes whose inner codes are parity-check codes. By using stronger inner codes, Chilappagari et al. (2010) showed that there is a linear-time decoding algorithm for every vertex expansion greater than 1/2. In this paper, it is shown that for every vertex expansion, there is a linear-time decoding algorithm for expander codes (using inner codes with minimum distance depending on the vertex expansion), and that the number of errors corrected is a constant fraction of the code length.
Auteurs: Michael Dowling;Shuhong Gao;
Apparue dans: IEEE Transactions on Information Theory
Date publication: 02.-2018, volume: 64, issue:2, pages: 972 - 978
Editeur: IEEE
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» Fast Discrimination of Transformer Magnetizing Current From Internal Faults: An Extended Kalman Filter-Based Approach
Résumé:
Differential protection is the most common type of protection in power transformers. However, inrush current due to transformer energization may appear as fault current to the protective relay, causing a false trip of the transformer. Therefore, discrimination of the transformer inrush current from internal faults is necessary to improve the security of the protection scheme. In this paper, a new method for discrimination of the transformer inrush current from an internal fault current is proposed. First, the nonlinear state-space model of a real single-phase transformer is derived, which incorporates the nonlinear phenomena of hysteresis and magnetic saturation. Based on the derived model, an Extended Kalman Filter (EKF) is used for estimation of the primary winding current. A residual signal is defined as the difference between the measured and estimated currents. When a healthy transformer is energized, the EKF perfectly estimates the primary winding current and, hence, the residual signal is almost zero. However, when the transformer is faulty, the EKF cannot effectively estimate the current due to the existing large model mismatches. Consequently, a large residual signal is created. The superiorities of the proposed algorithm are demonstrated using different experimental scenarios.
Auteurs: Farshid Naseri;Zahra Kazemi;Mohammad Mehdi Arefi;Ebrahim Farjah;
Apparue dans: IEEE Transactions on Power Delivery
Date publication: 02.-2018, volume: 33, issue:1, pages: 110 - 118
Editeur: IEEE
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» Fast Randomized Singular Value Thresholding for Low-Rank Optimization
Résumé:
Rank minimization can be converted into tractable surrogate problems, such as Nuclear Norm Minimization (NNM) and Weighted NNM (WNNM). The problems related to NNM, or WNNM, can be solved iteratively by applying a closed-form proximal operator, called Singular Value Thresholding (SVT), or Weighted SVT, but they suffer from high computational cost of Singular Value Decomposition (SVD) at each iteration. We propose a fast and accurate approximation method for SVT, that we call fast randomized SVT (FRSVT), with which we avoid direct computation of SVD. The key idea is to extract an approximate basis for the range of the matrix from its compressed matrix. Given the basis, we compute partial singular values of the original matrix from the small factored matrix. In addition, by developping a range propagation method, our method further speeds up the extraction of approximate basis at each iteration. Our theoretical analysis shows the relationship between the approximation bound of SVD and its effect to NNM via SVT. Along with the analysis, our empirical results quantitatively and qualitatively show that our approximation rarely harms the convergence of the host algorithms. We assess the efficiency and accuracy of the proposed method on various computer vision problems, e.g., subspace clustering, weather artifact removal, and simultaneous multi-image alignment and rectification.
Auteurs: Tae-Hyun Oh;Yasuyuki Matsushita;Yu-Wing Tai;In So Kweon;
Apparue dans: IEEE Transactions on Pattern Analysis and Machine Intelligence
Date publication: 02.-2018, volume: 40, issue:2, pages: 376 - 391
Editeur: IEEE
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» Fast Scheduling of Robot Teams Performing Tasks With Temporospatial Constraints
Résumé:
The application of robotics to traditionally manual manufacturing processes requires careful coordination between human and robotic agents in order to support safe and efficient coordinated work. Tasks must be allocated to agents and sequenced according to temporal and spatial constraints. Also, systems must be capable of responding on-the-fly to disturbances and people working in close physical proximity to robots. In this paper, we present a centralized algorithm, named “Tercio,” that handles tightly intercoupled temporal and spatial constraints. Our key innovation is a fast, satisficing multi-agent task sequencer inspired by real-time processor scheduling techniques and adapted to leverage a hierarchical problem structure. We use this sequencer in conjunction with a mixed-integer linear program solver and empirically demonstrate the ability to generate near-optimal schedules for real-world problems an order of magnitude larger than those reported in prior art. Finally, we demonstrate the use of our algorithm in a multirobot hardware testbed.
Auteurs: Matthew C. Gombolay;Ronald J. Wilcox;Julie A. Shah;
Apparue dans: IEEE Transactions on Robotics
Date publication: 02.-2018, volume: 34, issue:1, pages: 220 - 239
Editeur: IEEE
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» Fast Smoke Detection for Video Surveillance Using CUDA
Résumé:
Smoke detection is a key component of disaster and accident detection. Despite the wide variety of smoke detection methods and sensors that have been proposed, none has been able to maintain a high frame rate while improving detection performance. In this paper, a smoke detection method for surveillance cameras is presented that relies on shape features of smoke regions as well as color information. The method takes advantage of the use of a stationary camera by using a background subtraction method to detect changes in the scene. The color of the smoke is used to assess the probability that pixels in the scene belong to a smoke region. Due to the variable density of the smoke, not all pixels of the actual smoke area appear in the foreground mask. These separate pixels are united by morphological operations and connected-component labeling methods. The existence of a smoke region is confirmed by analyzing the roughness of its boundary. The final step of the algorithm is to check the density of edge pixels within a region. Comparison of objects in the current and previous frames is conducted to distinguish fluid smoke regions from rigid moving objects. Some parts of the algorithm were boosted by means of parallel processing using compute unified device architecture graphics processing unit, thereby enabling fast processing of both low-resolution and high-definition videos. The algorithm was tested on multiple video sequences and demonstrated appropriate processing time for a realistic range of frame sizes.
Auteurs: Alexander Filonenko;Danilo Cáceres Hernández;Kang-Hyun Jo;
Apparue dans: IEEE Transactions on Industrial Informatics
Date publication: 02.-2018, volume: 14, issue:2, pages: 725 - 733
Editeur: IEEE
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» Fast Spatial Resolution Analysis of Quadratic Penalized Least-Squares Image Reconstruction With Separate Real and Imaginary Roughness Penalty: Application to fMRI
Résumé:
Penalized least-squares iterative image reconstruction algorithms used for spatial resolution-limited imaging, such as functional magnetic resonance imaging (fMRI), commonly use a quadratic roughness penalty to regularize the reconstructed images. When used for complex-valued images, the conventional roughness penalty regularizes the real and imaginary parts equally. However, these imaging methods sometimes benefit from separate penalties for each part. The spatial smoothness from the roughness penalty on the reconstructed image is dictated by the regularization parameter(s). One method to set the parameter to a desired smoothness level is to evaluate the full width at half maximum of the reconstruction method’s local impulse response. Previous work has shown that when using the conventional quadratic roughness penalty, one can approximate the local impulse response using an FFT-based calculation. However, that acceleration method cannot be applied directly for separate real and imaginary regularization. This paper proposes a fast and stable calculation for this case that also uses FFT-based calculations to approximate the local impulse responses of the real and imaginary parts. This approach is demonstrated with a quadratic image reconstruction of fMRI data that uses separate roughness penalties for the real and imaginary parts.
Auteurs: Valur T. Olafsson;Douglas C. Noll;Jeffrey A. Fessler;
Apparue dans: IEEE Transactions on Medical Imaging
Date publication: 02.-2018, volume: 37, issue:2, pages: 604 - 614
Editeur: IEEE
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» Fast Supervised Discrete Hashing
Résumé:
Learning-based hashing algorithms are “hot topics” because they can greatly increase the scale at which existing methods operate. In this paper, we propose a new learning-based hashing method called “fast supervised discrete hashing” (FSDH) based on “supervised discrete hashing” (SDH). Regressing the training examples (or hash code) to the corresponding class labels is widely used in ordinary least squares regression. Rather than adopting this method, FSDH uses a very simple yet effective regression of the class labels of training examples to the corresponding hash code to accelerate the algorithm. To the best of our knowledge, this strategy has not previously been used for hashing. Traditional SDH decomposes the optimization into three sub-problems, with the most critical sub-problem - discrete optimization for binary hash codes - solved using iterative discrete cyclic coordinate descent (DCC), which is time-consuming. However, FSDH has a closed-form solution and only requires a single rather than iterative hash code-solving step, which is highly efficient. Furthermore, FSDH is usually faster than SDH for solving the projection matrix for least squares regression, making FSDH generally faster than SDH. For example, our results show that FSDH is about 12-times faster than SDH when the number of hashing bits is 128 on the CIFAR-10 data base, and FSDH is about 151-times faster than FastHash when the number of hashing bits is 64 on the MNIST data-base. Our experimental results show that FSDH is not only fast, but also outperforms other comparative methods.
Auteurs: Jie Gui;Tongliang Liu;Zhenan Sun;Dacheng Tao;Tieniu Tan;
Apparue dans: IEEE Transactions on Pattern Analysis and Machine Intelligence
Date publication: 02.-2018, volume: 40, issue:2, pages: 490 - 496
Editeur: IEEE
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» Faster-Than-Nyquist Precoded CAP Modulation Visible Light Communication System Based on Nonlinear Weighted Look-Up Table Predistortion
Résumé:
In this paper, we have experimentally demonstrated faster-than-Nyquist carrierless amplitude and phase modulation quadrature phase-shift keying visible light communication system over 1.5-m free space transmission. Weighted look-up table is used to mitigate nonlinear impairment caused by amplifiers and electro-optical components. At the receiver side, recursive least square is employed to improve the decision precision. By combining these techniques, a data rate of 1.01 Gb/s is experimentally achieved with a bit error rate less than 7% forward error correction limit of $3.8 times 10^{- 3}$ . To the best of our knowledge, this is the first time that weighted look-up table is proposed and used in visible light communication system.
Auteurs: Shangyu Liang;Zihao Jiang;Liang Qiao;Xingyu Lu;Nan Chi;
Apparue dans: IEEE Photonics Journal
Date publication: 02.-2018, volume: 10, issue:1, pages: 1 - 9
Editeur: IEEE
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» Father of Fuzzy Logic [Editor's Remarks]
Résumé:
Presents the introductory editorial for this issue of the publication.
Auteurs: Hisao Ishibuchi;
Apparue dans: IEEE Computational Intelligence Magazine
Date publication: 02.-2018, volume: 13, issue:1, pages: 2 - 2
Editeur: IEEE
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» Fault Detection Filtering for Nonhomogeneous Markovian Jump Systems via a Fuzzy Approach
Résumé:
This paper investigates the problem of the fault detection filter design for nonhomogeneous Markovian jump systems by a Takagi–Sugeno fuzzy approach. Attention is focused on the construction of a fault detection filter to ensure the estimation error dynamic stochastically stable, and the prescribed performance requirement can be satisfied. The designed fuzzy model-based fault detection filter can guarantee the sensitivity of the residual signal to faults and the robustness of the external disturbances. By using the cone complementarity linearization algorithm, the existence conditions for the design of fault detection filters are provided. Meanwhile, the error between the residual signal and the fault signal is made as small as possible. Finally, a practical application is given to illustrate the effectiveness of the proposed technique.
Auteurs: Fanbiao Li;Peng Shi;Cheng-Chew Lim;Ligang Wu;
Apparue dans: IEEE Transactions on Fuzzy Systems
Date publication: 02.-2018, volume: 26, issue:1, pages: 131 - 141
Editeur: IEEE
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» Fault Diagnosis and Fault-Tolerant Control Operation of Nonisolated DC–DC Converters
Résumé:
This paper proposes a fault diagnosis and identification method for nonisolated dc–dc converters. The method can detect the fault, and identify the faulty switch and the switch fault type in less than one switching cycle. The main idea is to apply the derivative of the inductor current based on the modulation of the particular dc–dc converter to provide a predictive current emulator model. The measured inductor current and its corresponding predicted current are used to diagnose the switch fault. The method, implemented in a digital signal processor, is robust to common converter asymmetry such as load variations, input disturbances, etc. The proposed fault diagnosis method has been analyzed, tested, and validated for a boost converter.
Auteurs: Elham Pazouki;Yilmaz Sozer;J. Alexis De Abreu-Garcia;
Apparue dans: IEEE Transactions on Industry Applications
Date publication: 02.-2018, volume: 54, issue:1, pages: 310 - 320
Editeur: IEEE
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» Fault Investigations on Die-Cast Copper Rotors
Résumé:
It has been known for a long time that replacement of aluminum by copper, which has an advantage in high conductivity, can be an economic solution for various applications including electric vehicle in the development of energy efficient motors. In comparison to aluminum, copper die-casting is difficult to perform due to its high density, viscosity, and melting point. Owing to these reasons, the copper die-cast rotors evince several manufacturing problems. The objective of this work is to identify the various defects in the manufacturing of copper die-cast rotor, and identify the lamination coating condition that sustains copper die-cast pressure and temperature. It evaluates the effectiveness of lamination coating on limiting the eddy current loss and the recoating process to improve in case the eddy current loss is in excess due to copper die-casting.
Auteurs: Soby T. Varghese;Bhim Singh;K. R. Rajagopal;
Apparue dans: IEEE Transactions on Industry Applications
Date publication: 02.-2018, volume: 54, issue:1, pages: 184 - 194
Editeur: IEEE
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» Fault-Tolerant Direct Torque Control of Five-Phase FTFSCW-IPM Motor Based on Analogous Three-Phase SVPWM for Electric Vehicle Applications
Résumé:
High reliability is important in motor driving system for electric vehicle applications. In this paper, a fault-tolerant direct torque control for a five-phase fault-tolerant fractional-slot concentrated-winding interior-permanent-magnet (FTFSCW-IPM) motor under the open-circuit condition of a single phase is proposed, in which an analogous three-phase space vector pulse width modulation (SVPWM) control strategy is adopted. The DTC system for the five-phase PM motor based on healthy SVPWM has several advantages of improved currents and low torque and flux ripples. To achieve the fault-tolerant operation of the SVPWM-DTC system, an analogous three-phase SVPWM strategy is proposed. The proposed SVPWM fault-tolerant control scheme is achieved by the division of six sectors and the reconfiguration of six equal nonzero voltage vectors, which is quickly computed and easily realized. In addition, based on a 2-kW FTFSCW-IPM motor prototype, the good performances of the proposed fault-tolerant drive are validated by both simulations and experiments, in which the average torque and low torque ripple during fault can be maintained. Finally, the dynamic performances under healthy and fault-tolerant conditions are measured. The results show that the proposed analogous three-phase SVPWM control can offer good dynamic performance, which is comparable to the healthy SVPWM.
Auteurs: Li Zhang;Ying Fan;Ronghua Cui;Robert D. Lorenz;Ming Cheng;
Apparue dans: IEEE Transactions on Vehicular Technology
Date publication: 02.-2018, volume: 67, issue:2, pages: 910 - 919
Editeur: IEEE
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» Faultprog: Testing the Accuracy of Binary-Level Software Fault Injection
Résumé:
Off-The-Shelf (OTS) software components are the cornerstone of modern systems, including safety-critical ones. However, the dependability of OTS components is uncertain due to the lack of source code, design artifacts and test cases, since only their binary code is supplied. Fault injection in components’ binary code is a solution to understand the risks posed by buggy OTS components. In this paper, we consider the problem of the accurate mutation of binary code for fault injection purposes. Fault injection emulates bugs in high-level programming constructs (assignments, expressions, function calls, ...) by mutating their translation in binary code. However, the semantic gap between the source code and its binary translation often leads to inaccurate mutations. We propose Faultprog, a systematic approach for testing the accuracy of binary mutation tools. Faultprog automatically generates synthetic programs using a stochastic grammar, and mutates both their binary code with the tool under test, and their source code as reference for comparisons. Moreover, we present a case study on a commercial binary mutation tool, where Faultprog was adopted to identify code patterns and compiler optimizations that affect its mutation accuracy.
Auteurs: Domenico Cotroneo;Anna Lanzaro;Roberto Natella;
Apparue dans: IEEE Transactions on Dependable and Secure Computing
Date publication: 02.-2018, volume: 15, issue:1, pages: 40 - 53
Editeur: IEEE
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» FDA-MIMO Radar Range–Angle Estimation: CRLB, MSE, and Resolution Analysis
Résumé:
Multiple-input multiple-output (MIMO) radar enjoys the advantage of increased degrees-of-freedom and spatial diversity gain, but it cannot effectively resolves the targets closely spaced in the same angle cell (but different range cells). Frequency diverse array (FDA)-MIMO radar can handle this problem by exploiting its range-dependent beampattern. FDA-MIMO radar was, thus, suggested for range–angle estimation of targets. Nevertheless, it is necessary to provide theoretical performance analysis for such a relatively new radar technique. Since multiple signal classification (MUSIC) algorithm is widely adopted in most of the FDA-MIMO literature, this paper derives the Cramér–Rao lower bound and mean square error expressions in MUSIC-based range–angle estimation algorithms for a general FDA-MIMO radar. Furthermore, the corresponding range and angle resolution thresholds in target detection and localization are also derived. Numerical results verify that the FDA-MIMO indeed outperforms conventional MIMO radar in both range–angle estimation and resolution threshold performance.
Auteurs: Jie Xiong;Wen-Qin Wang;Kuandong Gao;
Apparue dans: IEEE Transactions on Aerospace and Electronic Systems
Date publication: 02.-2018, volume: 54, issue:1, pages: 284 - 294
Editeur: IEEE
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» February 1878: The first phonograph
Résumé:
WHEN THOMAS EDISON DIED IN 1931, at 84, he held nearly 1,100 patents in the United States and more than 2,300 patents worldwide. By far the most famous one was his patent for the lightbulb, but he came up neither with the idea of an evacuated glass container nor with the use of an incandescing filament. More fundamental was Edison's conception, entirely de novo, of the complete system of electricity generation, transmission, and conversion, which he put into operation first in London and in lower Manhattan in 1882.
Auteurs: Vaclav Smil;
Apparue dans: IEEE Spectrum
Date publication: 02.-2018, volume: 55, issue:2, pages: 24 - 24
Editeur: IEEE
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» FEDERAL: A Framework for Distance-Aware Privacy-Preserving Record Linkage
Résumé:
In privacy-preserving record linkage, a number of data custodians encode their records and submit them to a trusted third-party who is responsible for identifying those records that refer to the same real-world entity. In this paper, we propose FEDERAL, a novel record linkage framework that implements methods for anonymizing both string and numerical data values, which are typically present in data records. These methods rely on a strong theoretical foundation for rigorously specifying the dimensionality of the anonymization space, into which the original values are embedded, to provide accuracy and privacy guarantees under various models of privacy attacks. A key component of the applied embedding process is the threshold that is required by the distance computations, which we prove can be formally specified to guarantee accurate results. We evaluate our framework using three real-world data sets with varying characteristics. Our experimental findings show that FEDERAL offers a complete and effective solution for accurately identifying matching anonymized record pairs (with recall rates constantly above 93 percent) in large-scale privacy-preserving record linkage tasks.
Auteurs: Dimitrios Karapiperis;Aris Gkoulalas-Divanis;Vassilios S. Verykios;
Apparue dans: IEEE Transactions on Knowledge and Data Engineering
Date publication: 02.-2018, volume: 30, issue:2, pages: 292 - 304
Editeur: IEEE
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» Feedforward FFT Hardware Architectures Based on Rotator Allocation
Résumé:
In this paper, we present new feedforward FFT hardware architectures based on rotator allocation. The rotator allocation approach consists in distributing the rotations of the FFT in such a way that the number of edges in the FFT that need rotators and the complexity of the rotators are reduced. Radix-2 and radix-2k feedforward architectures based on rotator allocation are presented in this paper. Experimental results show that the proposed architectures reduce the hardware cost significantly with respect to previous FFT architectures.
Auteurs: Mario Garrido;Shen-Jui Huang;Sau-Gee Chen;
Apparue dans: IEEE Transactions on Circuits and Systems I: Regular Papers
Date publication: 02.-2018, volume: 65, issue:2, pages: 581 - 592
Editeur: IEEE
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» Femtosecond Laser Microfabricated Optofluidic Grating Refractometer
Résumé:
A novel femtosecond laser microfabricated optofluidic grating is proposed and demonstrated in this letter, which realizes the measurement of refractive index of liquid. The diffraction grating is fabricated with an epoxy-based negative photoresist (SU-8) on glass substrate by femtosecond laser-induced two-photon polymerization and bonded with a polydimethylsiloxane microchannel, for which the transmission spectrum can be modulated by changing the refractive index of the liquid flowing in the microchannel. Experimental observation on the shift of the transmission peak wavelength indicates that the sensitivity of the diffraction grating is higher for a lower-order mode or a thicker grating, i.e., blue-shifted peak wavelength with a magnitude of $3.586times 10^{3},,mu text{m}$ per refractive index unit for the second-order mode of the grating with a thickness of 3.60 $mu text{m}$ .
Auteurs: Daiying Zhang;Liqiu Men;Qiying Chen;
Apparue dans: IEEE Photonics Technology Letters
Date publication: 02.-2018, volume: 30, issue:4, pages: 395 - 398
Editeur: IEEE
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» Femtosecond Optical Kerr Gate With Double Gate Pulses
Résumé:
We proposed an improved femtosecond optical Kerr gate with double gate pulses (DOKG) using a femtosecond laser, in which an ultrashort switching time can be realized even when a relatively slow response optical Kerr medium of carbon disulfide was used. The results showed that when the time delay and the light intensity ratio of the two pump pulses were adjusted to be about 140 fs and 1:0.9, the switching time and the maximum transmission efficiency of the DOKG could be optimized to be about 130 fs and 37%. The DOKG is convenient to be built and offers a good choice for applications based on ultrafast optical switch.
Auteurs: Wenjiang Tan;Jun Ma;Yipeng Zheng;Junyi Tong;
Apparue dans: IEEE Photonics Technology Letters
Date publication: 02.-2018, volume: 30, issue:3, pages: 266 - 269
Editeur: IEEE
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» Fiber In-Line Fabry-Perot Interferometer With Offset Splicing for Strain Measurement With Enhanced Sensitivity
Résumé:
We demonstrate a Fabry–Perot interferometer with inner air-cavity for ultrasensitive strain measurement. The device is fabricated by fusion splicing of two sections of etched multimode fiber with offset. By selecting the appropriate value of the offset, the strain sensitivity can be greatly increased. In the case of introducing two-dimensional offset, the strain sensitivity can be increased by more than 4.5 pm/μϵ when compared with that without offset. The device is simple in fabrication, robust in structure, economic in cost, and convenient in operation, and has high potential in many strain sensing applications.
Auteurs: Ye Liu;D. N. Wang;
Apparue dans: IEEE Photonics Journal
Date publication: 02.-2018, volume: 10, issue:1, pages: 1 - 8
Editeur: IEEE
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» Fiber In-Line Michelson Interferometer Based on Inclined Narrow Slit Crossing the Fiber Core
Résumé:
We demonstrate a new type of optical fiber in-line Michelson interferometer, in which an inclined narrow slit inside the single mode fiber, fabricated by femtosecond laser, plays the role of a beam splitter. The inclined narrow slit splits the incident light beam into two parts; one is introduced to the cladding-air interface and reflected back and the other is still guided in the fiber core and reflected at the fiber end. The two reflected beams recombine at the edge of inclined narrow slit and form a Michelson interferometer. Such a device is ultra-compact in size, robust in mechanical strength, and simple in fabrication, and can be used in refractive index and temperature sensing. Moreover, the device has good high temperature sustainability up to 1000 °C.
Auteurs: Ye Liu;D. N. Wang;
Apparue dans: IEEE Photonics Technology Letters
Date publication: 02.-2018, volume: 30, issue:3, pages: 293 - 296
Editeur: IEEE
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» Fiber-Optic Biosensor to Detect pH and Glucose
Résumé:
In this paper, we propose fast, highly sensitive, and wide-dynamic-range fiber-optic probe-type biosensors to detect pH and glucose. The operation principle of the proposed biosensors is based on the Fabry–Perot interferometry technique. Three pH-sensitive dyes (methyl orange, methyl red, and thymol blue) and three solvatochromic dyes (Nile red, rhodamine-B, and 4-amino-N-methylphthalimide) were individually mixed with polymers to obtain five pH- and three glucose-sensitive sensing membranes. These membranes were subsequently deposited on eight gold nanoparticles coated on fiber-optic probes to obtain five pH and three glucose fiber-optic probe sensors. To ascertain the effectiveness of the sensors, various concentrations of pH buffer solutions and glucose solutions were tested. The proposed fiber-optic pH and glucose probe sensors showed sensitivities of 1.95 nm/pH and 3.25 nm/mM, respectively, with high-sensing stability with the relative standard deviation about 2.5%. The proposed sensors offer a linear sensing ability over wide ranges of pH (2–12) and glucose ( $1~mu text{M}$ –1 M) with an R2 value of approximately 0.996. The response and recovery times of the proposed sensors were approximately 8 and 9 s, respectively. Finally in this paper, we compared the performance of the proposed fiber-optic probe sensors with that of other pH and glucose sensors and determined that the proposed sensors achieve better sensing performance.
Auteurs: Md. Rajibur Rahaman Khan;Apurva Vinodrao Watekar;Shin-Won Kang;
Apparue dans: IEEE Sensors Journal
Date publication: 02.-2018, volume: 18, issue:4, pages: 1528 - 1538
Editeur: IEEE
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» Fifth-Order T-Type Passive Resonant Tanks Tailored for Constant Current Resonant Converters
Résumé:
Fifth-order T-type resonant converter (RC) topologies for constant current applications are introduced in this paper. Immittance property in passive resonant tanks (PRTs) of the RCs is the key feature for realizing this purpose. In comparison with the lower order PRTs, the fifth-order topologies have more inherent current robustness against load variation, less sensitivity to the parameters variation and current gain tuning ability. At first, resonant networks qualifying the PRT conditions are specified with their topological superiorities description. Without loss of generality, 28 immittance PRTs (IPRTs) are detected as possible candidates that can be used as a voltage source to current source converter. In addition, their immittance operating conditions are analyzed mathematically. For prototyping, a topology has been selected and designed using a method based on minimization of the IPRT elements size. Moreover, closed-form expressions of the output current and voltage/current stresses on the reactive elements are derived and verified for selecting the elements value. The designed prototype is a 150-W constant current RC with tight load regulation ability. Experimental results show that the ZVS operation with low reactive power on the switches as well as minimum losses on the rectifier diodes are achieved in a wide range of load variations.
Auteurs: Alireza Khoshsaadat;Javad Shokrollahi Moghani;
Apparue dans: IEEE Transactions on Circuits and Systems I: Regular Papers
Date publication: 02.-2018, volume: 65, issue:2, pages: 842 - 853
Editeur: IEEE
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» Filter Bank Regularized Common Spatial Pattern Ensemble for Small Sample Motor Imagery Classification
Résumé:
For the last few years, many feature extraction methods have been proposed based on biological signals. Among these, the brain signals have the advantage that they can be obtained, even by people with peripheral nervous system damage. Motor imagery electroencephalograms (EEG) are inexpensive to measure, offer a high temporal resolution, and are intuitive. Therefore, these have received a significant amount of attention in various fields, including signal processing, cognitive science, and medicine. The common spatial pattern (CSP) algorithm is a useful method for feature extraction from motor imagery EEG. However, performance degradation occurs in a small-sample setting (SSS), because the CSP depends on sample-based covariance. Since the active frequency range is different for each subject, it is also inconvenient to set the frequency range to be different every time. In this paper, we propose the feature extraction method based on a filter bank to solve these problems. The proposed method consists of five steps. First, motor imagery EEG is divided by a using filter bank. Second, the regularized CSP (R-CSP) is applied to the divided EEG. Third, we select the features according to mutual information based on the individual feature algorithm. Fourth, parameter sets are selected for the ensemble. Finally, we classify using ensemble based on features. The brain–computer interface competition III data set IVa is used to evaluate the performance of the proposed method. The proposed method improves the mean classification accuracy by 12.34%, 11.57%, 9%, 4.95%, and 4.47% compared with CSP, SR-CSP, R-CSP, filter bank CSP (FBCSP), and SR-FBCSP. Compared with the filter bank R-CSP ( $beta $ , $gamma $ ), which is a parame- er selection version of the proposed method, the classification accuracy is improved by 3.49%. In particular, the proposed method shows a large improvement in performance in the SSS.
Auteurs: Sang-Hoon Park;David Lee;Sang-Goog Lee;
Apparue dans: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Date publication: 02.-2018, volume: 26, issue:2, pages: 498 - 505
Editeur: IEEE
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» Filter Design with Adaptation to Time-Delay Parameters for Genetic Regulatory Networks
Résumé:
In existing works, the filters designed for delayed genetic regulatory networks (GRNs) contain time delay. If the time delay is unknown, the filters do not work in practical applications. In order to overcome the shortcoming in such existing works, this paper studies the filter design problem of GRNs with unknown constant time delay, and a novel adaptive filter is introduced, in which all unknown network parameters and the unknown time delay can be estimated online. By Lyapunove approach, it is shown that the estimating errors asymptotically converge to the origin. Finally, simulation results are presented to illustrate the effectiveness of the new method proposed in this paper.
Auteurs: Hongmei Jiao;Michael Shi;Qikun Shen;Junwu Zhu;Peng Shi;
Apparue dans: IEEE/ACM Transactions on Computational Biology and Bioinformatics
Date publication: 02.-2018, volume: 15, issue:1, pages: 323 - 329
Editeur: IEEE
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» Fine-Grained Object Recognition and Zero-Shot Learning in Remote Sensing Imagery
Résumé:
Fine-grained object recognition that aims to identify the type of an object among a large number of subcategories is an emerging application with the increasing resolution that exposes new details in image data. Traditional fully supervised algorithms fail to handle this problem where there is low between-class variance and high within-class variance for the classes of interest with small sample sizes. We study an even more extreme scenario named zero-shot learning (ZSL) in which no training example exists for some of the classes. ZSL aims to build a recognition model for new unseen categories by relating them to seen classes that were previously learned. We establish this relation by learning a compatibility function between image features extracted via a convolutional neural network and auxiliary information that describes the semantics of the classes of interest by using training samples from the seen classes. Then, we show how knowledge transfer can be performed for the unseen classes by maximizing this function during inference. We introduce a new data set that contains 40 different types of street trees in 1-ft spatial resolution aerial data, and evaluate the performance of this model with manually annotated attributes, a natural language model, and a scientific taxonomy as auxiliary information. The experiments show that the proposed model achieves 14.3% recognition accuracy for the classes with no training examples, which is significantly better than a random guess accuracy of 6.3% for 16 test classes, and three other ZSL algorithms.
Auteurs: Gencer Sumbul;Ramazan Gokberk Cinbis;Selim Aksoy;
Apparue dans: IEEE Transactions on Geoscience and Remote Sensing
Date publication: 02.-2018, volume: 56, issue:2, pages: 770 - 779
Editeur: IEEE
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» Fine-Grained Scheduling in Cloud Gaming on Heterogeneous CPU-GPU Clusters
Résumé:
Cloud gaming is a promising approach to provide high-quality gaming services to mobile devices. However, existing cloud gaming systems fail to fully exploit hardware resources due to coarse-grained resource scheduling based on virtual machine migration. In this article, we propose a novel cloud gaming design, referred to as FGCG, with fine-grained scheduling to maximize resource utilization on a heterogeneous CPU-GPU cluster. Specifically, we decompose game workloads into small and independent render tasks that can be freely dispatched to different machines. Trace-driven simulation results show that FGCG can significantly improve resource utilization compared to existing cloud gaming systems.
Auteurs: Wei Zhang;Xiaofei Liao;Peng Li;Hai Jin;Li Lin;Bing Bing Zhou;
Apparue dans: IEEE Network
Date publication: 02.-2018, volume: 32, issue:1, pages: 172 - 178
Editeur: IEEE
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» Finite Size Effects in Highly Scaled Ruthenium Interconnects
Résumé:
Ru has been considered a candidate to replace Cu-based interconnects in VLSI circuits. Here, a methodology is proposed to predict the resistivity of (Ru) interconnects. First, the dependence of the Ru thin film resistivity on the film thickness is modeled by the semiclassical Mayadas-Shatzkes (MS) approach. The fitting parameters thus obtained are then used as input in a modified MS model for nanowires to calculate wire resistivities. Predicted experimental resistivities agreed within about 10%. The results further indicate that grain boundary scattering was the dominant scattering mechanism in scaled Ru interconnects.
Auteurs: Shibesh Dutta;Kristof Moors;Michiel Vandemaele;Christoph Adelmann;
Apparue dans: IEEE Electron Device Letters
Date publication: 02.-2018, volume: 39, issue:2, pages: 268 - 271
Editeur: IEEE
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» Finite-Difference Relaxation for Parallel Computation of Ionized Field of HVDC Lines
Résumé:
Ionized field calculations for high-voltage direct current (HVDC) transmission line is a computationally demanding problem, which can benefit from the application of massively parallel high-performance compute architectures. The finite element method (FEM) commonly employed to solve this problem is both memory and execution time intensive. In this paper, a finite-difference relaxation (FDR) method is proposed to solve a unipolar and a bipolar ionized field problem in an HVDC line. The novel FDR method has several advantages over FEM. First, the scheme is suitable for massively parallel computation and runs much faster: Compared with the commercial FEM software Comsol Multiphysics, the speed-up is more than 14 times in CPU parallelization and 35 times in graphics processor parallel implementation, while providing high accuracy. Moreover, the set of equations in FDR need not be assembled; instead, it is solved by a relaxation scheme and requires much less memory than FEM. Additionally, differentiated grid size with interpolation techniques is proposed to improve the flexibility of FDR for problem domain containing irregular geometries or disproportional sizes.
Auteurs: Peng Liu;Venkata Dinavahi;
Apparue dans: IEEE Transactions on Power Delivery
Date publication: 02.-2018, volume: 33, issue:1, pages: 119 - 129
Editeur: IEEE
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» Fisherposes for Human Action Recognition Using Kinect Sensor Data
Résumé:
This paper proposes a new method for view-invariant action recognition that utilizes the temporal position of skeletal joints obtained by Kinect sensor. In this method, the actions are represented as sequences of several pre-defined poses. After pre-processing, which includes skeleton alignment and scaling, the appropriate feature vectors are obtained for recognizing and discriminating the pose of every frame by the proposed Fisherposes method. The proposed regularized Mahalanobis distance metric is used in order to recognize both the involuntary and highly made-up actions at the same time. Hidden Markov model (HMM) is then used to classify the action related to an input sequence of poses. For taking into account the motion in the actions which are not separable by solely their temporal poses, histograms of trajectories are also proposed. The proposed action recognition method is capable of recognizing both the voluntary and involuntary actions, as well as pose-based and trajectory-based ones with a high accuracy rate. The effectiveness of the proposed method is experimented on three publicly available data sets, TST fall detection, UTKinect, and UCFKinect data sets.
Auteurs: Benyamin Ghojogh;Hoda Mohammadzade;Mozhgan Mokari;
Apparue dans: IEEE Sensors Journal
Date publication: 02.-2018, volume: 18, issue:4, pages: 1612 - 1627
Editeur: IEEE
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» Fixed-Time Consensus Tracking for Multiagent Systems With High-Order Integrator Dynamics
Résumé:
This paper addresses the fixed-time leader–follower consensus problem for high-order integrator multiagent systems subject to matched external disturbances. A new cascade control structure, based on a fixed-time distributed observer, is developed to achieve the fixed-time consensus tracking control. A simulation example is included to show the efficacy and the performance of the proposed control structure with respect to different initial conditions.
Auteurs: Zongyu Zuo;Bailing Tian;Michael Defoort;Zhengtao Ding;
Apparue dans: IEEE Transactions on Automatic Control
Date publication: 02.-2018, volume: 63, issue:2, pages: 563 - 570
Editeur: IEEE
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» Flat-Panel See-Through Three-Dimensional Display Based on Integral Imaging Using a Transparent Polarized Point Light Source Array
Résumé:
This study proposes a technique to implement see-through three-dimensional (3-D) display based on point light source integral imaging. This display consists of an edge-lit light guide plate, a polarizer array, and a transparent liquid crystal display (LCD) panel without rear polarizer. The combination of the light guide plate and the polarizer array act as a transparent polarized point light source array (PLSA), and reconstructs the 3-D image with the elemental image array loaded on the LCD panel. The background rays passing through the gaps in the polarized PLSA carry the object information and implement see-through property. The experimental system is constructed based on 1-D integral imaging to verify the proposed method. The see-through and superposition capabilities of the proposed method are demonstrated.
Auteurs: Zi Wang;Piao Dai;Guoqiang Lv;Qibin Feng;
Apparue dans: IEEE Photonics Journal
Date publication: 02.-2018, volume: 10, issue:1, pages: 1 - 7
Editeur: IEEE
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» Flexible Baseband-Unit Aggregation Enabled by Reconfigurable Multi-IF Over WDM Fronthaul
Résumé:
In cloud-radio access network, baseband-unit (BBU) aggregation schemes have been intensively discussed to improve the efficiency of resources in light traffic times. Also, driven by the emerging optical fronthaul, traffic migration is introduced in optical fronthaul to help realize BBU aggregation, based on which traffic exchange within BBU pool can be reduced, thus decreasing corresponding processing latency and energy consumption. However, these traffic migration schemes are operated in a time-division multiplexing way and are not suitable for multi-IF over wavelength-division multiplexing (WDM) fronthaul. In this paper, we propose a reconfigurable multi-IF over WDM fronthaul to support BBU aggregation. Based on IF traffic migration and optical path reconfiguration, traffic of multiple cell sites can be routed to one BBU to achieve BBU aggregation. Proof-of-concept experiments are demonstrated to verify the feasibility of the proposed architecture. For 4G+ deployment as specified in 3GPP protocol, 100-MHz orthogonal frequency-division multiplexing signal with 64 quadratic-amplitude modulation format after transmission shows that 3.5% error vector magnitude can be achieved.
Auteurs: Haiyun Xin;Hao He;Kuo Zhang;Syed Baqar Hussain;Weisheng Hu;
Apparue dans: IEEE Photonics Journal
Date publication: 02.-2018, volume: 10, issue:1, pages: 1 - 10
Editeur: IEEE
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» Flexible Pressure Sensor With High Sensitivity and Low Hysteresis Based on a Hierarchically Microstructured Electrode
Résumé:
Flexible pressure sensors are crucial for E-skins to enable tactile sensing capabilities. However, flexible pressure sensors often exhibit high hysteretic response caused by internal and external mechanical dissipations in flexible materials. The hysteresis gives rise to reliability issues, especially in the presence of dynamic stress. In this letter, we report a flexible capacitive pressure sensor design with hierarchically microstructured electrodes to obtain both high sensitivity and low hysteresis. The sparsely spaced large pyramid microstructure improves the sensitivity, whereas the small pyramid reduces the hysteresis caused by interfacial adhesion. The optimized sensor shows excellent performances in terms of high sensitivity (~3.73 kPa−1), ultralow detection limits (0.1 Pa), significantly reduced hysteresis (~4.42%), and enhanced sensing capability for pluses, which demonstrates its potential for advanced electronic skins.
Auteurs: Wen Cheng;Jun Wang;Zhong Ma;Ke Yan;Yunmu Wang;Huiting Wang;Sheng Li;Yun Li;Lijia Pan;Yi Shi;
Apparue dans: IEEE Electron Device Letters
Date publication: 02.-2018, volume: 39, issue:2, pages: 288 - 291
Editeur: IEEE
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» Flow-Based Compromise Detection: Lessons Learned
Résumé:
Although the aggregated nature of exported flow data provides many advantages in terms of privacy and scalability, flow data may contain artifacts that impair data analysis. In this article, we investigate the differences between flow data analysis in theory and practice—that is, in lab environments and production networks.
Auteurs: Rick Hofstede;Aiko Pras;Anna Sperotto;Gabi Dreo Rodosek;
Apparue dans: IEEE Security & Privacy
Date publication: 02.-2018, volume: 16, issue:1, pages: 82 - 89
Editeur: IEEE
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» Focused Ultrasound Steering for Harmonic Motion Imaging
Résumé:
Harmonic motion imaging (HMI) is a radiation-force-based ultrasound elasticity imaging technique, which is designed for both tissue relative stiffness imaging and reliable high-intensity focused ultrasound treatment monitoring. The objective of this letter is to develop and demonstrate the feasibility of 2-D focused ultrasound (FUS) beam steering for HMI using a 93-element, FUS phased array. HMI with steered FUS beam was acquired in tissue-mimicking phantoms. The HMI displacement was imaged within the steering range of ±1.7 mm laterally and ±2 mm axially. Using the steered FUS beam, HMI can be used to image a larger tissue volume with higher efficiency and without requiring mechanical movement of the transducer.
Auteurs: Yang Han;Thomas Payen;Shutao Wang;Elisa Konofagou;
Apparue dans: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Date publication: 02.-2018, volume: 65, issue:2, pages: 292 - 294
Editeur: IEEE
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» Four-Way Chained Quasi-Planar Slotted-HMSIW Power Divider
Résumé:
A four-way chained quasi-planar slotted power divider, using half-mode substrate-integrated waveguide technology, is presented in this letter. Based on the equivalent-circuit model, slotted capacitive coupling model has been achieved. In order to verify the validity of the design method, a four-way power divider operating at X-band is designed, fabricated and measured. The simulation and measured results with good agreement are presented. The measured insertion loss (in the frequency range of 9.05–9.55 GHz) is less than 1.4 dB, and the return loss is better than 17.5 dB. The measured isolations between the output ports are greater than 12 dB at the entire design band.
Auteurs: Kaijun Song;Song Guo;Yong Fan;
Apparue dans: IEEE Microwave and Wireless Components Letters
Date publication: 02.-2018, volume: 28, issue:2, pages: 117 - 119
Editeur: IEEE
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» Fourier Collocation Approach With Mesh Refinement Method for Simulating Transit-Time Ultrasonic Flowmeters Under Multiphase Flow Conditions
Résumé:
A numerical model for transit-time ultrasonic flowmeters operating under multiphase flow conditions previously presented by us is extended by mesh refinement and grid point redistribution. The method solves modified first-order stress-velocity equations of elastodynamics with additional terms to account for the effect of the background flow. Spatial derivatives are calculated by a Fourier collocation scheme allowing the use of the fast Fourier transform, while the time integration is realized by the explicit third-order Runge–Kutta finite-difference scheme. The method is compared against analytical solutions and experimental measurements to verify the benefit of using mapped grids. Additionally, a study of clamp-on and in-line ultrasonic flowmeters operating under multiphase flow conditions is carried out.
Auteurs: Matej Simurda;Lars Duggen;Nils T. Basse;Benny Lassen;
Apparue dans: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Date publication: 02.-2018, volume: 65, issue:2, pages: 244 - 257
Editeur: IEEE
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» Fourier-Based Shape Servoing: A New Feedback Method to Actively Deform Soft Objects into Desired 2-D Image Contours
Résumé:
This paper addresses the design of a vision-based method to automatically deform soft objects into desired two-dimensional shapes with robot manipulators. The method presents an innovative feedback representation of the object's shape (based on a truncated Fourier series) and effectively exploits it to guide the soft object manipulation task. A new model calibration scheme that iteratively approximates a local deformation model from vision and motion sensory feedback is derived; this estimation method allows us to manipulate objects with unknown deformation properties. Pseudocode algorithms are presented to facilitate the implementation of the controller. Numerical simulations and experiments are reported to validate this new approach.
Auteurs: David Navarro-Alarcon;Yun-Hui Liu;
Apparue dans: IEEE Transactions on Robotics
Date publication: 02.-2018, volume: 34, issue:1, pages: 272 - 279
Editeur: IEEE
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» FOV Expansion of Bioinspired Multiband Polarimetric Imagers With Convolutional Neural Networks
Résumé:
Spectral and polarimetric contents of the light reflected from an object contain useful information on material type and surface characteristics of the object. Jointly exploiting spatial, spectral, and polarimetric information helps detect camouflage targets. Motivated by the vision mechanism of some known aquatic insects, we construct a bioinspired multiband polarimetric imaging system using a camera array, which simultaneously captures multiple images of different spectral bands and polarimetric angles. But the disparity between the fixed positions of each component camera leads to the loss of information in the boundary region and a reduction in the field of view (FOV). In order to overcome the limits, this paper presents a deep learning method for FOV expansion, incorporating the gradient prior of the image into a nine-dimensional convolutional neural network's framework to learn end-to-end mapping between the incomplete images and the FOV-expanded images. With FOV expansion, the proposed model recovers significant missing information. For the problem of insufficient training data, we construct the training dataset and propose the corresponding training methods to achieve good convergence of the network. We also provide some experimental results to validate its state-of-the-art performance of FOV expansion.
Auteurs: Yongqiang Zhao;Miaomiao Wang;Guang Yang;Jonathan Cheung-Wai Chan;
Apparue dans: IEEE Photonics Journal
Date publication: 02.-2018, volume: 10, issue:1, pages: 1 - 14
Editeur: IEEE
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» Fractal-Shaped Metamaterial Absorbers for Multireflections Mitigation in the UHF Band
Résumé:
A Minkowski fractal geometry is proposed in this letter as miniaturized absorber cell suitable for multipath phenomena mitigation within the European RFID UHF band. The proposed structure is analyzed through the combined use of an equivalent transmission line model and method-of-moments-based full-wave simulations. Very high miniaturization capabilities (about 50% with respect to standard configurations) are demonstrated for an 868 MHz absorber unit cell, characterized by an absorptivity more than 99%, a good angular stability, and a very thin substrate (≤λ0/100). The proposed configuration is appealing for designing compact absorbers useful for multipath reduction in wireless systems operating on restricted indoor environments.
Auteurs: Francesca Venneri;Sandra Costanzo;Giuseppe Di Massa;
Apparue dans: IEEE Antennas and Wireless Propagation Letters
Date publication: 02.-2018, volume: 17, issue:2, pages: 255 - 258
Editeur: IEEE
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» Fraction of Insertion of the Channel Fin as Performance Booster in Strain-Engineered p-FinFET Devices With Insulator-on-Silicon Substrate
Résumé:
The combined impact of process- and substrate-induced stress has been analytically modeled for a rectangular fin inserted into an insulator-on-silicon (IOS) substrate. Stress estimation and profiling are performed for different fractional insertion of the fin into the IOS substrate and the induced stress values are observed to saturate for ≥1/3 of the fin insertion. Therefore, a one-third of inserted Si fin is used to estimate the induced stress by following a standard FinFET process flow. Uniaxial compressive stress as high as 4.6 GPa has been obtained, and it has also been observed that the hole mobility can be enhanced to a significantly high value by judiciously choosing the gate dielectrics and fractional insertion of the fin. Thereby, the design of symmetric CMOS by using such mobility-enhanced p-FinFET is possible. Moreover, the current–voltage characteristics of such strain-engineered p-FinFETs exhibit improved drain-induced barrier lowering and subthreshold swing and ~45% enhancement of drain current.
Auteurs: Sulagna Chatterjee;Sanatan Chattopadhyay;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 02.-2018, volume: 65, issue:2, pages: 411 - 418
Editeur: IEEE
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» Freedom of Encryption
Résumé:
Legislation surrounding digital privacy has seen quite an upheaval in recent years. The introduction of the General Data Protection Regulation (GDPR) in the EU, and new resolutions within the United Nations Human Rights Council (UNHRC) have recognized the urgency to include recommendations on the use of encryption to protect the digital identities of citizens. In this work, we meander through the main events in history which have shaped the legislative landscape that encompasses the use of encryption, paying particular attention to recent (post-Snowden) developments.
Auteurs: Aisling Connolly;
Apparue dans: IEEE Security & Privacy
Date publication: 02.-2018, volume: 16, issue:1, pages: 102 - 103
Editeur: IEEE
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» Frequency Control of Island VSC-HVDC Links Operating in Parallel With AC Interconnectors and Onsite Generation
Résumé:
The main scope of this paper is to propose a suitable frequency control scheme for high-voltage dc-links (HVDC) based on voltage source converters (VSCs), operating in island systems with on-site conventional generation and external ac interconnectors. The proposed droop-type and inertia emulator is built upon the power synchronization control (PSC) concept, where grid synchronization is achieved without the need of a dedicated synchronization unit. The dynamics of the proposed PSC-based scheme are assessed both in frequency and time domain, utilizing a realistic study-case system, which corresponds to the current planning for the interconnection of Crete to the Greek mainland system, involving ac and dc interconnectors operating in parallel with conventional local thermal units. To demonstrate the benefits offered by the proposed controller in the context of frequency response, a detailed average value model is developed for the VSC-HVDC link in MATLAB/Simulink, where severe contingencies are simulated, such as the sudden loss of the external ac interconnector or local generation, leading from mainland grid-connected to islanded operation.
Auteurs: Sotirios I. Nanou;Stavros A. Papathanassiou;
Apparue dans: IEEE Transactions on Power Delivery
Date publication: 02.-2018, volume: 33, issue:1, pages: 447 - 454
Editeur: IEEE
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» Frequency Domain Analysis and Optimal Design of Isolated Bidirectional Series Resonant Converter
Résumé:
This paper presents an optimal design approach for a dual-active-bridge series resonant converter (DABSRC) based on frequency domain analysis. The proposed design technique ensures efficient performance of DABSRC over a wide range of voltage gain and load variations. The operating principle of the converter is detailed to illustrate both zero voltage switching (ZVS) and zero current switching operations during bidirectional power transfer. Modeling the current-dependent power loss components as an equivalent series resistance, the converter is analyzed in frequency domain to derive amplitude and phase of the state variables accurately. Performing the power loss analysis in a normalized form, the characteristic equations for bidirectional power transfer, tank current, converter efficiency, and ZVS criteria are derived. Using these characteristics, the design of DABSRC is formulated as an efficiency optimization problem. Particle swarm optimization technique is adopted to determine the optimal tank parameters and transformer turns-ratio. Converter performance is evaluated on a 120-W lab-prototype, and peak efficiency of 95.2% and California energy commission efficiency of 92.1% are achieved. Close agreement among analytical predictions, numerical simulation, and experimental results validate the proposed design technique.
Auteurs: Utsab Kundu;Bhavit Pant;Supratik Sikder;Ashok Kumar;Parthasarathi Sensarma;
Apparue dans: IEEE Transactions on Industry Applications
Date publication: 02.-2018, volume: 54, issue:1, pages: 356 - 366
Editeur: IEEE
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» Frequency Noise Characterization of a 25-GHz Diode-Pumped Mode-Locked Laser With Indirect Carrier-Envelope Offset Noise Assessment
Résumé:
We present a detailed frequency noise characterization of an ultrafast diode-pumped solid-state laser operating at 25-GHz repetition rate. The laser is based on the gain material Er:Yb:glass and operates at a wavelength of 1.55 μm. Using a beating measurement with an ultralow-noise continuous-wave laser in combination with a dedicated electrical scheme, we measured the frequency noise properties of an optical mode of the 25-GHz laser, of its repetition rate and indirectly of its carrier-envelope offset (CEO) signal without detecting the CEO frequency by the standard approach of nonlinear interferometry. We observed a strong anticorrelation between the frequency noise of the indirect CEO signal and of the repetition rate in our laser, leading to optical modes with a linewidth below 300 kHz in the free-running laser (at 100-ms integration time), much narrower than the individual contributions of the carrier envelope offset and repetition rate. We explain this behavior by the presence of a fixed point located close to the optical carrier in the laser spectrum for the dominant noise source.
Auteurs: Pierre Brochard;Valentin Johannes Wittwer;Sławomir Bilicki;Bojan Resan;Kurt John Weingarten;Stéphane Schilt;Thomas Südmeyer;
Apparue dans: IEEE Photonics Journal
Date publication: 02.-2018, volume: 10, issue:1, pages: 1 - 10
Editeur: IEEE
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» Frequency- and Bandwidth-Tunable Bandstop Filter Containing Variable Coupling Between Transmission Line and Resonator
Résumé:
This paper presents a frequency- and bandwidth-tunable bandstop filter using substrate-integrated wave- guide (SIW) resonators. For designing such a filter, this paper also presents a tunable coupling structure between a microstrip line and an SIW resonator for obtaining the bandwidth tuning capability. The coupling structure has two coupling slots between the microstrip line and the resonator, and the phase shift between the two slots determines the overall external coupling value of the resonator. This external coupling value can be controlled by making use of a phase shifter, which in turn makes it possible to adjust the bandwidth of a bandstop filter. A thorough mathematical analysis is shown using the equivalent circuit model of the presented coupling structure, and it has been verified by measuring an SIW resonator containing the presented structure. The presented tunable coupling structure has also been applied to a design of bandstop filter that can be tuned from 2.8 to 3.4 GHz. The measured results at 3.1 GHz show that the bandwidth can be tuned from 0 (all-pass) to 96 MHz reaching the attenuation level of 44 dB.
Auteurs: Seong-Wook Jeong;Juseop Lee;
Apparue dans: IEEE Transactions on Microwave Theory and Techniques
Date publication: 02.-2018, volume: 66, issue:2, pages: 943 - 953
Editeur: IEEE
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» Frequency-Dependent Multiconductor Transmission Line Model With Collocated Voltage and Current Propagation
Résumé:
This paper reviews the classical multiconductor transmission line (MTL) equations and proposes additional constraints on these equations. A fundamental physical constraint is that the voltage and current waves must be collocated and travel together with the same propagation function. Based on this condition, the Revised Multiconductor Transmission Line (RMTL) equations are proposed. As opposed to the classical MTL equations that require complex frequency-dependent transformation matrices for their diagonalization, the RMTL equations can be diagonalized very accurately using a single real constant transformation matrix. A new Frequency-Dependent Line Model (FDLM) is proposed based on the RMTL equations. FDLM is compared with the two most accepted frequency-dependent line models in the Electromagnetic Transients Program (EMTP): The JMARTI model (fdLine) that uses a constant transformation matrix as an approximation, and the phase-coordinates Universal Line Model (ULM) that fits the frequency dependence of the transformation matrices. These time-domain models are compared with a reference frequency-domain solution for a double-circuit vertical line.
Auteurs: José R. Martí;Arash Tavighi;
Apparue dans: IEEE Transactions on Power Delivery
Date publication: 02.-2018, volume: 33, issue:1, pages: 71 - 81
Editeur: IEEE
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» From Cell to Tissue Properties—Modeling Skin Electroporation With Pore and Local Transport Region Formation
Résumé:
Current models of tissue electroporation either describe tissue with its bulk properties or include cell level properties, but model only a few cells of simple shapes in low-volume fractions or are in two dimensions. We constructed a three-dimensional model of realistically shaped cells in realistic volume fractions. By using a ‘unit cell’ model, the equivalent dielectric properties of whole tissue could be calculated. We calculated the dielectric properties of electroporated skin. We modeled electroporation of single cells by pore formation on keratinocytes and on the papillary dermis which gave dielectric properties of the electroporated epidermis and papillary dermis. During skin electroporation, local transport regions are formed in the stratum corneum. We modeled local transport regions and increase in their radii or density which affected the dielectric properties of the stratum corneum. The final model of skin electroporation accurately describes measured electric current and voltage drop on the skin during electroporation with long low-voltage pulses. The model also accurately describes voltage drop on the skin during electroporation with short high-voltage pulses. However, our results indicate that during application of short high-voltage pulses additional processes may occur which increase the electric current. Our model connects the processes occurring at the level of cell membranes (pore formation), at the level of a skin layer (formation of local transport region in the stratum corneum) with the tissue (skin layers) and even level of organs (skin). Using a similar approach, electroporation of any tissue can be modeled, if the morphology of the tissue is known.
Auteurs: Janja Dermol-Černe;Damijan Miklavčič;
Apparue dans: IEEE Transactions on Biomedical Engineering
Date publication: 02.-2018, volume: 65, issue:2, pages: 458 - 468
Editeur: IEEE
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» From Microscopic to Macroscopic Description of Composite Thin Panels: A Road Map for Their Simulation in Time Domain
Résumé:
In this paper, we show a simulation strategy for composite dispersive thin-panels, starting from their microscopic characteristics and ending into a time-domain macroscopic model. In a first part, we revisit different semianalytic methods that may be used to obtain the S-parameter matrices. The validity of them is assessed with numerical simulations and experimental data. We also include some formulas that may be used to tailor the shielding effectiveness of panels in a design phase. In a second part, we present an extension to dispersive media of a subgridding hybrid implicit–explicit algorithm finite difference time domain (FDTD) devised by the authors to deal with that kind of materials. The method, here presented and applied to the FDTD method, is a robustly stable alternative to classical impedance boundary condition techniques. For this, a previous analytical procedure allowing to extract an equivalent effective media from S-parameters is presented, thus making this road map able to simulate any kind of dispersive thin layer. A numerical validation of the algorithm is finally shown by comparing with experimental data.
Auteurs: Luis Diaz Angulo;Miguel Ruiz Cabello;Jesus Alvarez;Amelia Rubio Bretones;Salvador G. García;
Apparue dans: IEEE Transactions on Microwave Theory and Techniques
Date publication: 02.-2018, volume: 66, issue:2, pages: 660 - 668
Editeur: IEEE
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» From Software-Defined to Human-Defined Networking: Challenges and Opportunities
Résumé:
The SDN paradigm is still in an early stage of development. Considering full automatization and effortless management as the main objective of these networks, we believe diverse challenges need to be tackled. For this purpose, this article reviews the SDN architecture from top to bottom, paying attention to components yet under standardization or that demand enhancement from a network operator's perspective. The main conclusion is that the SDN area requires a significant amount of research to reach its full potential, which we consider a huge opportunity to innovate toward a truly human-defined networking.
Auteurs: Elisa Rojas;
Apparue dans: IEEE Network
Date publication: 02.-2018, volume: 32, issue:1, pages: 179 - 185
Editeur: IEEE
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» From the Editor-in-Chief
Résumé:
Auteurs: M. Rice;
Apparue dans: IEEE Transactions on Aerospace and Electronic Systems
Date publication: 02.-2018, volume: 54, issue:1, pages: 1 - 1
Editeur: IEEE
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» From the editors' desk
Résumé:
Presents the introductory editorial for this issue of the publication.
Auteurs: Robert Fleming;
Apparue dans: IEEE Electrical Insulation Magazine
Date publication: 02.-2018, volume: 34, issue:1, pages: 5 - 6
Editeur: IEEE
Document complet vers site de l'éditeur
 
» From Voice of Evidence to Redirections
Résumé:
The Voice of Experience department is being relaunched as Redirections, which will focus on the surprises in software engineering.
Auteurs: Rafael Prikladnicki;Tim Menzies;
Apparue dans: IEEE Software
Date publication: 02.-2018, volume: 35, issue:1, pages: 11 - 13
Editeur: IEEE
Document complet vers site de l'éditeur
 
» Full Wavefield Analysis and Damage Imaging Through Compressive Sensing in Lamb Wave Inspections
Résumé:
One of the main challenges faced by the structural health monitoring community is acquiring and processing huge sets of acoustic wavefield data collected from sensors, such as scanning laser Doppler vibrometers or ultrasonic scanners. In fact, extracting information that allows the estimation of the damage condition of a structure can be a time-consuming process. This paper presents a damage detection and localization technique based on a compressive sensing algorithm, which significantly allows us to reduce the acquisition time without losing in detection accuracy. The proposed technique exploits the sparsity of the wavefield in different representation domains, such as those spanned by wave atoms, curvelets, and Fourier exponentials to recover the full wavefield and, at the same time, to infer the damage location, based on comparison between the wavefield reconstructions produced by the different representation domains. The procedure is applied to three different setups related to an aluminum plate with a notch, a glass fiber reinforced polymer plate with a notch, and a composite plate with a delamination. The results show that the technique can be applied in a variety of structural components to reduce acquisition time and achieve high performance in defect detection and localization by removing up to 80% of the Nyquist sampling grid.
Auteurs: Yasamin Keshmiri Esfandabadi;Luca De Marchi;Nicola Testoni;Alessandro Marzani;Guido Masetti;
Apparue dans: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Date publication: 02.-2018, volume: 65, issue:2, pages: 269 - 280
Editeur: IEEE
Document complet vers site de l'éditeur
 
» Full-Duplex Cognitive Radio With Asynchronous Energy-Efficient Sensing
Résumé:
Using a novel embedded Markov chain, we model and analyze a cognitive radio performing full-duplex spectrum sensing which is being carried out imperfectly—i.e., with errors—and asynchronously with primary traffic, from the perspective of energy efficiency. The effect of sensing frequency, which is varied by inserting sleeping periods between sensing processes is investigated, with focus on: 1) the energy efficiency of the device measured in terms of the number of successful transmissions under a limited battery budget; 2) the average throughput; and 3) the collision with the primary’s traffic. We show analytically that, given false-alarm and mis-detection probabilities, the device’s operation in lower-than-maximum sensing frequency may be more energy-efficient than that in maximum-frequency sensing case, while the radio is neither suffering throughput degradation nor disturbing the primary traffic seriously. We validate the deployment of such full-duplex cognitive radio (FDCR) along with the proposed sensing scheme for low-power short-range applications like wireless machine-to-machine communications and sensor networks, where the share of sensing power is comparable to that of transmission power. The merits of the proposed FDCR scheme are demonstrated through comparisons with a half-duplex cognitive radio scheme under different operating conditions and full-duplex self-interference cancellation factors.
Auteurs: Ali Bayat;Sonia Aïssa;
Apparue dans: IEEE Transactions on Wireless Communications
Date publication: 02.-2018, volume: 17, issue:2, pages: 1066 - 1080
Editeur: IEEE
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» Full-Reference Objective Quality Assessment of Tone-Mapped Images
Résumé:
In this paper we present a novel method for full-reference image quality assessment (IQA) of tone-mapped images displayed on standard low dynamic range (LDR) displays. Due to the dynamic range compression caused by the tone-mapping process a mixture of several artifacts and distortions may be produced in the tone-mapped images. This makes the quality assessment of the tone-mapped images very challenging. Due to the diversity of such artifacts and distortions we propose a “bag of features” (BOF) approach to tackle this problem. Specifically in the proposed method a number of different perceptually relevant quality-related features are first extracted from a given tone-mapped image and its reference HDR image. These features are designed such that they capture different aspects and attributes of the tone-mapped image such as its structural fidelity naturalness and overall brightness. A support vector regressor is then trained based on the extracted features and it is used for measuring the visual quality of a tone-mapped image. Our experimental results indicate that the proposed method achieves high accuracy as compared to several existing methods.
Auteurs: Hadi Hadizadeh;Ivan V. Bajić;
Apparue dans: IEEE Transactions on Multimedia
Date publication: 02.-2018, volume: 20, issue:2, pages: 392 - 404
Editeur: IEEE
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» Fully Distributed Hierarchical Control of Parallel Grid-Supporting Inverters in Islanded AC Microgrids
Résumé:
In this paper, a fully distributed hierarchical control strategy is proposed for operating networked grid-supporting inverters (GSIs) in islanded ac microgrids (MGs). The primary control level implements frequency and voltage control of an ac MG through a cascaded structure, consisting of a droop control loop, a virtual impedance control loop, a mixed ${H_2}/{H_infty }$-based voltage control loop, and a sliding-mode-control-based current loop. Compared to conventional proportional-plus-integral-based cascaded control, the proposed cascaded control does not require a precise model for the GSI system. The proposed secondary control level implements distributed-consensus-based economic automatic generation control and distributed automatic voltage control, which integrates the conventional secondary control and tertiary control into a single control level by bridging a gap between traditional secondary control and tertiary control. Simulation results demonstrate the effectiveness of the proposed hierarchical control strategy.
Auteurs: Zhongwen Li;Chuanzhi Zang;Peng Zeng;Haibin Yu;Shuhui Li;
Apparue dans: IEEE Transactions on Industrial Informatics
Date publication: 02.-2018, volume: 14, issue:2, pages: 679 - 690
Editeur: IEEE
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» Fully Polarimetric Bistatic Radar Calibration With Modified Dihedral Objects
Résumé:
We introduce the design of dihedral reflectors that are used to calibrate an instrumented, dual-linearly polarized, wide-bistatic compact radar range operating at 160 GHz. The polarization scattering matrix of this bistatic calibration object may be tailored to rotate the incident linear polarization state to a slant polarization state in a fashion that is similar to the 90° dihedral that is used for calibrating monostatic polarimeters. The bistatic calibration object that we describe here is capable of introducing this polarization rotation while simultaneously steering the mainlobe of its specular reflection to the receiver. As we demonstrate, this characteristic of the mainlobe-steered dihedral (MSD) object can be achieved over a wide range of bistatic angles. The MSD object possesses a variety of desirable qualities for the calibration of bistatic polarimeters, but they are particularly useful for those systems that do not possess the capability to rotate their feed arrangement (e.g., millimeter-/ submillimeter-wave waveguide-based systems). Through both computational and experimental results, we demonstrate the capability of the MSD object to calibrate and characterize the accuracy (better than 0.5 dB) and polarization purity (~50 dB) of a 160 GHz dual-linearly polarized, bistatic compact radar range at 15°, 45°, and 75° bistatic angles.
Auteurs: C. Beaudoin;T. Horgan;G. Demartinis;M. J. Coulombe;A. J. Gatesman;W. E. Nixon;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 02.-2018, volume: 66, issue:2, pages: 937 - 950
Editeur: IEEE
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» Fundamental Study of Hexadecane Removal by Atmospheric Microplasma
Résumé:
In recent years, the deterioration of indoor air quality (IAQ) became a big concern. Because indoors is the place where we spend most of our life, an IAQ is an important factor to be considered for comfortable and healthy living. In this study, we evaluated the products and decomposition process of hexadecane in small and large capacity spaces by using microplasma electrode. In the case of hexadecane removal, both small and large capacity microplasma process could reduce hexadecane by 83% and 89%, respectively. In the process, we found various hydrocarbons such as 1-hexene (C6H12), 1-heptene (C7H14), and 1-octene (C8H 16) as intermediate products. CO2 and N2O were also confirmed as final products of the microplasma treatment process.
Auteurs: Kazuo Shimizu;Yusuke Kurokawa;Marius Blajan;
Apparue dans: IEEE Transactions on Industry Applications
Date publication: 02.-2018, volume: 54, issue:1, pages: 599 - 604
Editeur: IEEE
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» FUNNEL: Assessing Software Changes in Web-Based Services
Résumé:
The detection of performance changes in software change roll-outs in Internet-based services is crucial for an operations team, because it allows timely roll-back of a software change when performance degrades unexpectedly. However, it is infeasible to manually investigate millions of performance measurements of many roll-outs. In this paper, we present an automated tool, FUNNEL, for rapid and robust impact assessment of software changes in large Internet-based services. FUNNEL automatically collects the related performance measurements for each software change. To detect significant performance behavior changes, FUNNEL adopts singular spectrum transform (SST) algorithm as the core algorithm, uses various techniques to improve its robustness and reduce its computational cost, and applies a difference-in-difference (DiD) method to differentiate the true causality from the random correlations between the performance change and the software change. Evaluation through historical data in real-word services shows that FUNNEL achieves accuracy of more than 99.7 percent. Compared with previous methods, FUNNEL’s detection delay is 38.02 to 64.99 percent shorter, and its computation speed is 4.59-7,098 times faster. In real deployment, FUNNEL achieves a 98.21 percent precision, high robustness, fast detection speed, and shows its capability in detecting unexpected behavior changes.
Auteurs: Shenglin Zhang;Ying Liu;Dan Pei;Yu Chen;Xianping Qu;Shimin Tao;Zhi Zang;Xiaowei Jing;Mei Feng;
Apparue dans: IEEE Transactions on Services Computing
Date publication: 02.-2018, volume: 11, issue:1, pages: 34 - 48
Editeur: IEEE
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» Further Progress in the Electrostatic Nucleation of Water Vapor
Résumé:
The planet's atmosphere holds a vast amount of water. Existing state-of-the-art “atmospheric water generation” systems mostly work by cooling the entire air flow below the dew point, which require significant amounts of energy per liter of water. As a result, the cost of this water is similar to that of imported bottled water in small single-use plastic containers. Therefore, there is an urgent need for any technology that generates usable water in an energy-efficient manner. It is known that the native dipole moment of water molecule results in the nucleation of liquid phase on carriers of electrical charge due to the suppressed evaporation. Nevertheless, the practical implementation of electrostatic water nucleation (EWN) is still in the stage of laboratory demonstrations. This work summarizes the theoretical background of the phenomenon and past experimental data, presents further experimental results and new data from practical implementation of EWN, and analyzes options for the further development.
Auteurs: Michael Reznikov;Matthew Salazar;Martin Page;Melixa Rivera-Sustache;
Apparue dans: IEEE Transactions on Industry Applications
Date publication: 02.-2018, volume: 54, issue:1, pages: 591 - 598
Editeur: IEEE
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» Fused Silica Micro Shell Resonator With T-Shape Masses for Gyroscopic Application
Résumé:
This paper presents a novel micro shell resonator (MSR) with T-shape masses based on fused silica using out-of-plane electrode structures. Eight circular-distributed T-shape masses are designed along the rim of resonator shell to improve transduction efficiency, including drive efficiency and detection efficiency. The dynamic parameters and transduction efficiency are calculated and optimized with finite element method, revealing 3.76 times improvement in drive efficiency, 4.65 times improvement in detection efficiency, and 17.81 times increase in mechanical sensitivity. In addition, it is feasible to trim the frequency by adding or removing mass on the T-shape masses. The key feature of the process is based on micro blow-torching process and whirling platform, which form the resonator structure with smooth roughness and good structure uniformity. Femtosecond laser ablation is used to release the T-shape masses for good symmetry and high processing quality. Then, metalized MSR with T-shape masses is assembled on a glass substrate. Electrostatic transduction is used to detect spatial deformation of resonators by out-of-plane electrodes, which reveals a frequency mismatch of 0.175% at 6904.4 Hz and 6916.5 Hz with quality factors of 20.39 k ( $tau =0.94$ s) and $Q = 36.94$ k ( $tau =1.7text{s}$ ). [2017-0086]
Auteurs: Dingbang Xiao;Wei Li;Zhanqiang Hou;Kun Lu;Yan Shi;Yulie Wu;Xuezhong Wu;
Apparue dans: Journal of Microelectromechanical Systems
Date publication: 02.-2018, volume: 27, issue:1, pages: 47 - 58
Editeur: IEEE
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» Gain Enhancement for Wideband CP ME-Dipole Antenna by Loading With Spiral Strip in Ku-Band
Résumé:
One novel single-feed single-layer wideband circularly polarized magnetoelectric dipole antenna with enhanced gain property is presented in this communication. By loading coplanar spiral with the radiating patch, the unidirectional radiation gain of the antenna is effectively improved while the impedance bandwidth and axial ratio (AR) bandwidth unaffected. Surface current distributions with/without the spiral are compared to reveal the antenna’s mechanism. The measurement shows that the left-hand circular polarized antenna features the impedance bandwidth from 11.4 to 18.5 GHz (or 52%), an AR bandwidth from 13.2 to 18 GHz (or 32%), and the maximum gain of 11.1 dBic at 16.9 GHz with 3 dB gain bandwidth from 12.5 to 18.6 GHz (or 36.1%). Owning to the low profile, broadband, and high gain, the proposed antenna is a capable candidate for satellite communication.
Auteurs: Wenquan Cao;Qianqian Wang;Zuping Qian;Shujie Shi;Jun Jin;Kang Ding;Bing Zhang;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 02.-2018, volume: 66, issue:2, pages: 962 - 966
Editeur: IEEE
Document complet vers site de l'éditeur
 
» Gain-Switched 2-μm Fiber Laser System Providing Kilowatt Peak-Power Mode-Locked Resembling Pulses and Its Application to Supercontinuum Generation in Fluoride Fibers
Résumé:
A fast gain-switched Tm-doped fiber laser and amplifier system providing stable 17-ns pulses with a 0.64-mJ energy and 35.6-kW peak power at 25 kHz is demonstrated. Then, self-starting mode-locked resembling pulses with duration of <200 ps, recorded within the gain-switched pulse envelope, were achieved in the same laser cavity. By amplifying the pulse train in a Tm-doped fiber amplifier, an average output power of 6.8 W at a ∼15-ns full width at half maximum gain-switch envelope and a ∼36.9-μJ subpulse with a peak power of up to 115.6 kW were demonstrated. To the best of our knowledge, this is the shortest gain-switched and mode-locked-like pulse as well as the highest peak-power that has been demonstrated in this type of laser system. A mid-infrared supercontinuum generation with a total output power of 2.45 W and a cutoff wavelength at 4.4 μm is also reported.
Auteurs: Pawel Grzes;Jacek Swiderski;
Apparue dans: IEEE Photonics Journal
Date publication: 02.-2018, volume: 10, issue:1, pages: 1 - 8
Editeur: IEEE
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» Gallager Bound for MIMO Channels: Large- $N$ Asymptotics
Résumé:
The use of multiple antenna arrays in transmission and reception has become an integral part of modern wireless communications. To quantify the performance of such systems, the evaluation of bounds on the error probability of realistic finite length codewords is important. In this paper, we analyze the standard Gallager error bound for both constraints of maximum average power and maximum instantaneous power. Applying techniques from random matrix theory, we obtain analytic expressions of the error exponent when the length of the codeword increases to infinity at a fixed ratio with the antenna array dimensions. Analyzing its behavior at rates close to the ergodic rate, we find that the Gallager error bound becomes asymptotically close to an upper error bound obtained recently by Hoydis et al. 2015. We also obtain an expression for the Gallager exponent in the case when the codelength spans several Rayleigh fading blocks, hence taking into account the situation when the channel varies during each transmission.
Auteurs: Apostolos Karadimitrakis;Aris L. Moustakas;Romain Couillet;
Apparue dans: IEEE Transactions on Wireless Communications
Date publication: 02.-2018, volume: 17, issue:2, pages: 1323 - 1330
Editeur: IEEE
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» Gamesman Problems [Gamesman Problems]
Résumé:
Various puzzles, games, humorous definitions, or mathematical that should engage the interest of readers.
Auteurs: Athanasios Kakarountas;
Apparue dans: IEEE Potentials
Date publication: 02.-2018, volume: 37, issue:1, pages: 48 - 48
Editeur: IEEE
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» Gamesman Solutions [Gamesman Solutions]
Résumé:
Various puzzles, games, humorous definitions, or mathematical that should engage the interest of readers.
Auteurs: Athanasios Kakarountas;
Apparue dans: IEEE Potentials
Date publication: 02.-2018, volume: 37, issue:1, pages: 5 - 6
Editeur: IEEE
Document complet vers site de l'éditeur
 
» GaN Nanowire MOSFET With Near-Ideal Subthreshold Slope
Résumé:
Wrap-around gate GaN nanowire MOSFETs using Al2O3 as gate oxide have been experimentally demonstrated. The fabricated devices exhibit a minimum subthreshold slope of 60 mV/dec, an average subthreshold slope of 68 mV/dec over three decades of drain current, drain-induced barrier lowering of 27 mV/V, an on-current of $42~mu text {A}/mu text{m}$ (normalized by nanowire circumference), on/off ratio over $10^{8}$ , an intrinsic transconductance of $27.8~mu text {S}/mu text{m}$ , for a switching efficiency figure of merit, ${Q}={g}_{m}$ /SS of $0.41~mu text{S}/mu text{m}$ -dec/mV. These performance metrics make GaN nanowire MOSFETs a promising candidate for emerging low-power applications, such as sensors and RF for the Internet of Things.
Auteurs: Wenjun Li;Matt D. Brubaker;Bryan T. Spann;Kris A. Bertness;Patrick Fay;
Apparue dans: IEEE Electron Device Letters
Date publication: 02.-2018, volume: 39, issue:2, pages: 184 - 187
Editeur: IEEE
Document complet vers site de l'éditeur
 


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    2010:   janvier     février     mars     avril     mai     juin     juillet     août     septembre     octobre     novembre     décembre    
    2009:   janvier     février     mars     avril     mai     juin     juillet     août     septembre     octobre     novembre     décembre