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Publications dans les journaux scientifiques dans le domaine de l'ingénierie : 02-2018 trié par par titre, page: 3
» Blind Channel Estimation and Symbol Detection for Multi-Cell Massive MIMO Systems by Expectation Propagation
Résumé:
Massive MIMO systems exploit the favorable propagation condition of the radio channel, whereby the vector-valued channels between the base station (BS) and the terminals become mutually orthogonal. This property is used in a recently-proposed channel estimation method for multi-cell massive MIMO systems based on the eigenvalue decomposition (EVD) of the correlation matrix of the received vectors. In this paper, we present a blind channel estimation and symbol detection scheme for multi-cell massive MIMO systems based on expectation propagation (EP). The proposed algorithm is initialized with the channel estimation result from the EVD-based method. It is shown that in our EP formulation, channel estimation and symbol detection are “decoupled” in that EP iterations for channel estimation can be performed without the knowledge of the specific transmitted symbols. Therefore, channel estimation can be performed first followed by symbol detection. In particular, a liner symbol detection scheme such as zero-forcing (ZF) or minimum mean-squared error (MMSE) algorithm may be employed. Simulation results show that after a few iterations, the EP-based algorithm significantly improves the performance of the EVD-based method in both channel estimation and symbol error rate. Comparisons are also made with the results from a recently proposed blind detection scheme and it is shown that the proposed algorithm has better performance.
Auteurs: Kamran Ghavami;Mort Naraghi-Pour;
Apparue dans: IEEE Transactions on Wireless Communications
Date publication: 02.-2018, volume: 17, issue:2, pages: 943 - 954
Editeur: IEEE
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» Blind Demixing and Deconvolution at Near-Optimal Rate
Résumé:
We consider simultaneous blind deconvolution of $r$ source signals from their noisy superposition, a problem also referred to blind demixing and deconvolution. This signal processing problem occurs in the context of the Internet of Things where a massive number of sensors sporadically communicate only short messages over unknown channels. We show that robust recovery of message and channel vectors can be achieved via convex optimization when random linear encoding using i.i.d. complex Gaussian matrices is used at the devices and the number of required measurements at the receiver scales with the degrees of freedom of the overall estimation problem. Since the scaling is linear in $r$ our result significantly improves over recent works.
Auteurs: Peter Jung;Felix Krahmer;Dominik Stöger;
Apparue dans: IEEE Transactions on Information Theory
Date publication: 02.-2018, volume: 64, issue:2, pages: 704 - 727
Editeur: IEEE
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» Blinding Guidance Against Missiles Sharing Bearings-Only Measurements
Résumé:
A novel “blind and evade” guidance concept for an aerial target, which is exposed to a threat of two homing missiles, is presented. Each missile is assumed to measure solely its own line-of-sight (LOS) angle and share it with the other missile. Such information sharing enables the missiles to form a triangular measuring baseline relative to the target and to improve their estimation accuracy. However, if the separation angle between the two LOS vectors is small enough, the observability of such double-LOS measuring approach becomes weak. Motivated by this observation, the idea of the proposed concept is to bring the missiles on the same LOS with the target, i.e., blinding them, and then perform an appropriately timed target evasive maneuver. The target's guidance law is derived under the assumption of perfect information and formulated as an optimal control problem. Simulation results demonstrate the potential of the proposed defense concept.
Auteurs: Robert Fonod;Tal Shima;
Apparue dans: IEEE Transactions on Aerospace and Electronic Systems
Date publication: 02.-2018, volume: 54, issue:1, pages: 205 - 216
Editeur: IEEE
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» Block-Stream as a Service: A More Secure, Nimble, and Dynamically Balanced Cloud Service Model for Ambient Computing
Résumé:
Cloud computing has become mainstream in the last few years. Diverse services based on IaaS, PaaS, SaaS, and app store models have been widely available to millions of users worldwide. At the same time, transparent computing (TC) has also gained strong interest in China. With the rapid development of IoT, increasing IoT devices will be deployed to provide information services for end users. As we are heading into the era of ambient computing, where end users are immersed in seamless computing devices and services, the boundary between cloud and devices is getting blurry, and more devices and services need to be securely managed. The existing service models that are defined for user-cloud interaction should be extended to serve more diverse and lightweight devices with nimble and fluid services. With this evolution trend, it is paramount for both cloud service providers and IoT service operators to manage the security and integrity of these services. In this article, we propose a new cloud service model, named block-stream as a service (BaaS), based on our previous study on TC. BaaS is nimbler than SaaS and has better security management than an app store. It is expected that this new cloud service model has great potential to support the vision of ambient computing and securely manage diverse applications on lightweight IoT devices.
Auteurs: Jackson He;Yaoxue Zhang;Ju Lu;Ming Wu;Fujin Huang;
Apparue dans: IEEE Network
Date publication: 02.-2018, volume: 32, issue:1, pages: 126 - 132
Editeur: IEEE
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» Book Reviews [7 Reviews]
Résumé:
The following books are reviewed: Extreme-Temperature and Harsh-Environment Electronics by V. K. Khanna; Advances in Magnetic Materials—Processing, Properties, and Performance by S. Zhang and D. Zhao; Self-Healing Materials by G. Wypych; Renewable Energy Integration, 2nd Edition by L. E. Jones; High-Power Converters and AC Drives, 2nd Edition by B. Wu and M. Narimani; Power System SCADA and Smart Grids by M. S. Thomas and J. D. McDonald; Energy Storage by G. M. Crawley.
Auteurs: John J. Shea;
Apparue dans: IEEE Electrical Insulation Magazine
Date publication: 02.-2018, volume: 34, issue:1, pages: 64 - 67
Editeur: IEEE
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» Boost-Phase Trajectory Inference From Space-Borne LOS Measurements With a Sieve Method
Résumé:
Boost-phase trajectory inference is one of the major objectives of the space-borne missile early-warning system. Traditional methods can be classified as either profile-based or profile-free methods. The profile-based methods are accurate but inadaptable to the types of missiles, whereas the profile-free methods are adaptable but inaccurate. To integrate the strengths of the profile-based and profile-free methods, a multimodel trajectory inference approach is proposed. First, a general net acceleration model (GNAM) containing only type-free prior information is constructed by the method of sieves. Then, a new kind of net acceleration profile is proposed by incorporating type-dependent prior information into the GNAM. After that, the multimodel approach is proposed following the Bayesian framework. Simulations indicate that the approach is accurate in estimation and capable for type identification.
Auteurs: Taihe Yi;Bing Liu;Zhengming Wang;Zhen Shen;Dongyun Yi;
Apparue dans: IEEE Transactions on Aerospace and Electronic Systems
Date publication: 02.-2018, volume: 54, issue:1, pages: 339 - 352
Editeur: IEEE
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» Boosted Random Ferns for Object Detection
Résumé:
In this paper we introduce the Boosted Random Ferns (BRFs) to rapidly build discriminative classifiers for learning and detecting object categories. At the core of our approach we use standard random ferns, but we introduce four main innovations that let us bring ferns from an instance to a category level, and still retain efficiency. First, we define binary features on the histogram of oriented gradients-domain (as opposed to intensity-), allowing for a better representation of intra-class variability. Second, both the positions where ferns are evaluated within the sliding window, and the location of the binary features for each fern are not chosen completely at random, but instead we use a boosting strategy to pick the most discriminative combination of them. This is further enhanced by our third contribution, that is to adapt the boosting strategy to enable sharing of binary features among different ferns, yielding high recognition rates at a low computational cost. And finally, we show that training can be performed online, for sequentially arriving images. Overall, the resulting classifier can be very efficiently trained, densely evaluated for all image locations in about 0.1 seconds, and provides detection rates similar to competing approaches that require expensive and significantly slower processing times. We demonstrate the effectiveness of our approach by thorough experimentation in publicly available datasets in which we compare against state-of-the-art, and for tasks of both 2D detection and 3D multi-view estimation.
Auteurs: Michael Villamizar;Juan Andrade-Cetto;Alberto Sanfeliu;Francesc Moreno-Noguer;
Apparue dans: IEEE Transactions on Pattern Analysis and Machine Intelligence
Date publication: 02.-2018, volume: 40, issue:2, pages: 272 - 288
Editeur: IEEE
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» Bootstrapping and Resetting CMOS Starter for Thermoelectric and Photovoltaic Chargers
Résumé:
Sustaining microsensors for years is challenging because tiny batteries exhaust quickly, and recharging or replacing thousands of networked nodes is impracticable. Harnessing heat or light energy helps, but only when available. And even then, tiny generators output less than 300 mV, which is not enough to operate microelectronics well. This brief presents a 0.18- $mu$ m CMOS starter that charges a temporary 1.8-V supply quickly and reliably from slow- or fast-rising photovoltaic and thermoelectric sources. For this, a jump starter helps an LC tank oscillate to a level that allows a discharge path to output power. A resetter then continually resets the circuit until the system senses the temporary supply is ready. This way, with 1.8 V, a charging system can then charge a battery quickly before the onset of another harvesting drought. The starter does not require off-chip components because it borrows the switched inductor that the charging system already uses to charge the battery. A prototype of the starter proposed charges 120 pF to 1.8 V in 15–59 $mu$ s with 1.5%–7% efficiency from a 180 $Omega$ , 220–250-mV source.
Auteurs: Andrés A. Blanco;Gabriel A. Rincón-Mora;
Apparue dans: IEEE Transactions on Circuits and Systems II: Express Briefs
Date publication: 02.-2018, volume: 65, issue:2, pages: 156 - 160
Editeur: IEEE
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» Boundary Estimation of Imaged Object in Microwave Medical Imaging Using Antenna Resonant Frequency Shift
Résumé:
The performance of microwave imaging systems can be significantly improved by incorporating boundaries of the imaged object as a priori information. While it might be possible to manually measure that boundary in a controlled laboratory environment, this cannot be achieved in the clinical environment due to the impracticality of such a measurement in addition to the effect of the natural subject’s movement. In this paper, a method for boundary identification at the same time of imaging and using the same data captured for imaging is presented. The method is based on the relation between the imaging antennas’ resonant frequency and the location of the imaged object. The imaging antennas’ resonant frequency shifts when that antenna faces an imaging object, which is effectively a lossy dielectric in biomedical application, and that shift depends on the distance between the antenna and the object. The proposed technique is quite fast in scanning, computation, and image creation as it does not need additional devices for accurate boundary estimation. The method is tested via simulations and human trials using a torso imaging system. The collected data across the band 0.75–1.75 GHz using a 12-element antenna array, which is extended to 24 virtual elements, enclosing the human torso are processed to successfully estimate the torso boundary in a more accurate way than other methods. The included results in imaging a lung cancer case indicate that the accurate detection of the torso boundary improves microwave images.
Auteurs: Ali Zamani;S. Ahdi Rezaeieh;Konstanty S. Bialkowski;Amin M. Abbosh;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 02.-2018, volume: 66, issue:2, pages: 927 - 936
Editeur: IEEE
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» Bounds and Constructions for Optimal $(n, {3, 4, 5}, Lambda _a, 1, Q)$ -OOCs
Résumé:
Let $W={w_{1}, ldots , w_{r}}$ be a set of positive integers, $lambda _{c}$ a positive integer, $Lambda _{a}=(lambda _{a}^{(1)}, ldots lambda _{a}^{(r)})$ an $r$ -tuple of positive integers, and $Q=(q_{1}, ldots q_{r})$ an $r$ -tuple of positive rational numbers whose sum is 1. In 1996, Yang introduced variable-weight optical orthogonal code, $(n, W, Lambda _{a}, lambda _{c}, Q)$ -OOC, for multimedia optical CDMA systems with multiple quality of service (QoS) requirements. Some work had been done on the constructions of optimal $(n, W, Lambda _{a}, 1, Q)$ -OOCs with unequal auto-correlation constraints for $W={3, 4}$ and {3, 5}, while little is known on optimal $(n, W, Lambda _{a}, 1, Q)$ -OOCs for $|W|geq 3$ . In this paper, we focus our main attentions on $(n, {3, 4, 5}, Lambda _{a}, 1, Q)$ -OOCs with $Lambda _{a}in {(2, 1, 1), (2, 1, 2), (2, 2, 1), (2, 2, 2)}$ . Tight upper bounds on the maximum code size of $(n, {3, 4, 5}, Lambda _{- }, 1, Q)$ -OOCs are obtained, and infinite classes of optimal $(n, {3, 4, 5}, Lambda _{a}, 1, Q)$ -OOCs are constructed.
Auteurs: Huangsheng Yu;Shujuan Dang;Dianhua Wu;
Apparue dans: IEEE Transactions on Information Theory
Date publication: 02.-2018, volume: 64, issue:2, pages: 1361 - 1367
Editeur: IEEE
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» Brain MR Image Restoration Using an Automatic Trilateral Filter With GPU-Based Acceleration
Résumé:
Objective: Noise reduction in brain magnetic resonance (MR) images has been a challenging and demanding task. This study develops a new trilateral filter that aims to achieve robust and efficient image restoration. Methods: Extended from the bilateral filter, the proposed algorithm contains one additional intensity similarity funct-ion, which compensates for the unique characteristics of noise in brain MR images. An entropy function adaptive to intensity variations is introduced to regulate the contributions of the weighting components. To hasten the computation, parallel computing based on the graphics processing unit (GPU) strategy is explored with emphasis on memory allocations and thread distributions. To automate the filtration, image texture feature analysis associated with machine learning is investigated. Among the 98 candidate features, the sequential forward floating selection scheme is employed to acquire the optimal texture features for regularization. Subsequently, a two-stage classifier that consists of support vector machines and artificial neural networks is established to predict the filter parameters for automation. Results: A speedup gain of 757 was reached to process an entire MR image volume of 256 × 256 × 256 pixels, which completed within 0.5 s. Automatic restoration results revealed high accuracy with an ensemble average relative error of 0.53 ± 0.85% in terms of the peak signal-to-noise ratio. Conclusion: This self-regulating trilateral filter outperformed many state-of-the-art noise reduction methods both qualitatively and quantitatively. Significance: We believe that this new image restoration algorithm is of potential in many brain MR image processing applications that require expedition and automation.
Auteurs: Herng-Hua Chang;Cheng-Yuan Li;Audrey Haihong Gallogly;
Apparue dans: IEEE Transactions on Biomedical Engineering
Date publication: 02.-2018, volume: 65, issue:2, pages: 400 - 413
Editeur: IEEE
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» Bridged-T Coil for Miniature Dual-Band Branch-Line Coupler and Power Divider Designs
Résumé:
In this paper, a new design method for bridged-T coil (BTC) is proposed such that it can be made equivalent to two different transmission line sections at two different frequencies. In this way, on-chip dual-band branch-line coupler and dual-band power divider designs with very compact circuit sizes can be made possible through the use of BTCs. Specifically, the proposed 2.45/5.8-GHz dual-band branch-line coupler realized using the integrated passive device (IPD) process features a compact circuit size of only $2.8~text {mm} times 1.4$ mm while the proposed 2.4/5.5-GHz dual-band power divider in IPD exhibits a very small circuit size of only $1.8~text {mm} times 1.7$ mm. To the best of our knowledge, the proposed dual-band branch-line coupler is the smallest one ever reported while the circuit size of the proposed dual-band power divider is comparable to the smallest in the literature.
Auteurs: Wei-Ting Fang;En-Wei Chang;Yo-Shen Lin;
Apparue dans: IEEE Transactions on Microwave Theory and Techniques
Date publication: 02.-2018, volume: 66, issue:2, pages: 889 - 901
Editeur: IEEE
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» Bridging the Gap: Dialogue Between Engineers & Social Scientists [From the Editor]
Résumé:
This unique issue seeks to bridge the gap between engineers & social scientists and encourage dialogue between electric power professionals and social scientists who provide key insights into our customer base. Our guest editors compiled five well-written articles that challenge the usual way most electrical power system professionals think about our industry. As summarized in the "Guest Editorial," the issue identifies key behavioral factors that must be considered by engineers and ways that we should respond to customer concerns. Papers from the issue are briefly summarized.
Auteurs: Michael Henderson;
Apparue dans: IEEE Power and Energy Magazine
Date publication: 02.-2018, volume: 16, issue:1, pages: 4 - 6
Editeur: IEEE
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» Broadband Cloaking Obtained Using HOBBIES Optimization [EM Progammer's Notebook]
Résumé:
In this article, we describe the notion of a cloak achieved by employing the usual composite dielectrics surrounding a metal cube, a concept that was first presented by Hwang and Chin [1]. Here, we use an optimization procedure to improve on their results and obtain a three-dimensional composite dielectric structure that can achieve a better broadband match than that of [1]. The two structures of interest are an empty metallic waveguide and a metal cube placed inside the same waveguide but surrounded by different-sized dielectric slabs so that the effect of the metal cube in the transmitted fields inside the waveguide will not be much different from the fields that would exist in an empty waveguide. The dimensions and properties of the simple dielectrics making up the different slabs inside the waveguide are optimized using an electromagnetic simulator called Higher Order Basis Based Integral Equation Solver (HOBBIES) [2] so that the waveguide will appear empty by looking at the nature of the transmitted fields from the waveguide loaded with a metallic cube but surrounded by some dielectrics.
Auteurs: Hongsik Moon;Tapan K. Sarkar;Magdalena Salazar Palma;
Apparue dans: IEEE Antennas and Propagation Magazine
Date publication: 02.-2018, volume: 60, issue:1, pages: 112 - 117
Editeur: IEEE
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» Broadband Continuous-Mode Doherty Power Amplifiers With Noninfinity Peaking Impedance
Résumé:
In this paper, a broadband continuous-mode Doherty power amplifier (CM-DPA) is realized taking advantage of the noninfinity output impedances of peaking stage. Specifically, the carrier PA of the designed DPA operates in a continuous class-J mode when the peaking PA is in the OFF-state, where the output impedance of the peaking PA has some influences on the carrier PA. When the peaking transistor is in the OFF-state, the load impedance variation of the carrier transistor versus noninfinity peaking impedance is presented in this contribution. The proposed method surmounts the back-off drain efficiency deterioration of DPAs at two side working bands through elaborately processing the noninfinity peaking impedance. This paper also presents a method to derive the required OFF-state output impedance of the peaking stage by the carrier PA in a symmetrical broadband DPA. A broadband CM-DPA working over 1.6–2.7 GHz (bandwidth of 51%) is designed and fabricated for interpreting our theories. The simulated load trajectory of the carrier transistor is in line with the design space of continuous class-J mode. Under continuous wave excitation, experimental results show the drain efficiencies of 46.5%–63.5% at 6-dB output back-off power levels and 56%–75.3% at peaking power levels. The maximum output power of this DPA is 43.8–45.2 dBm with a gain of 9.4–11.5 dB across the whole working band. Furthermore, a 20-MHz LTE modulated signal with a peak-to-average power ratio of 7.4 dB is also applied to the fabricated CM-DPA at 2.2 GHz. At an average output power of 37.5 dBm, measurement results show the adjacent channel power ratios of −30.2 and −50.1 dBc before and after digital predistortion, respectively.
Auteurs: Weimin Shi;Songbai He;Xiaoyu Zhu;Bin Song;Zhitao Zhu;Gideon Naah;Min Zhang;
Apparue dans: IEEE Transactions on Microwave Theory and Techniques
Date publication: 02.-2018, volume: 66, issue:2, pages: 1034 - 1046
Editeur: IEEE
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» Broadband High-Energy All-Fiber Laser at 1.6 $mu$ m
Résumé:
A broadband high-energy all-fiber laser at 1.6- $mu text{m}$ window with erbium-doped fiber mode locked by nonlinear polarization rotation technology is demonstrated. The direct output optical spectrum centered at 1.6 $mu text{m}$ has a bandwidth of 52.4 nm. The fiber laser delivers a pulse energy of 3.9 nJ with 9.3-MHz repetition rate at 220-mW 976-nm pump power. Based on it, a wavelength-tunable optical source with a wavelength tuning range from 1.6 to 1.8 $mu text{m}$ is demonstrated through soliton self-frequency shift. To satisfy much longer wavelength demands in some special application scenario, e.g., deep brain imaging with multi-photon microscopy, a chirped pulse amplifier was constructed to boost the pulse energy to 14 nJ, and the wavelength can be tuned from 1.6 to 1.94 $mu text{m}$ with those amplified pulses. These fiber sources at the $L$ -band and a longer wavelength can explore a wider scope in deep biotissue imaging area for lower water absorption.
Auteurs: Jiqiang Kang;Cihang Kong;Pingping Feng;Xiaoming Wei;Zhi-Chao Luo;Edmund Y. Lam;Kenneth K. Y. Wong;
Apparue dans: IEEE Photonics Technology Letters
Date publication: 02.-2018, volume: 30, issue:4, pages: 311 - 314
Editeur: IEEE
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» Broadband IF-Over-Fiber Transmission With Parallel IM/PM Transmitter Overcoming Dispersion-Induced RF Power Fading for High-Capacity Mobile Fronthaul Links
Résumé:
We demonstrate a broadband and long-distance intermediate frequency-over-fiber (IFoF) transmission scheme employing a transmitter composed of parallel intensity/phase (IM/PM) modulators with appropriate bandwidth allocations to IM and PM. Due to the proposed scheme, we can eliminate all the null frequencies caused by dispersion-induced RF power fading, which, in turn, enables us to significantly increase the available bandwidth. In addition, our system does not require any synchronization between IM and PM, which reduces complexity compared to conventional parallel transmitter architecture. We successfully transmitted 20 $times$ 360 MHz filtered orthogonal-frequency-division-multiplexed signals corresponding to a common public radio interface equivalent data rate of 524.28 Gbps over a 30- and 40-km single-mode fiber satisfying the 8% threshold for the error-vector magnitude values for all the subcarriers. These results show that our proposed IFoF transmission scheme is scalable to long-distance mobile fronthaul links for 5G and beyond.
Auteurs: Shota Ishimura;Byung Gon Kim;Kazuki Tanaka;Kosuke Nishimura;Hoon Kim;Yun C. Chung;Masatoshi Suzuki;
Apparue dans: IEEE Photonics Journal
Date publication: 02.-2018, volume: 10, issue:1, pages: 1 - 9
Editeur: IEEE
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» Broadband Photonic Microwave Signal Processor With Frequency Up/Down Conversion and Phase Shifting Capability
Résumé:
A new dual-function photonic microwave signal processing structure that has the ability to realize both frequency up/down conversion and RF/IF phase shifting, is presented. In the proposed signal processor, a dual-polarization dual-parallel Mach Zehnder modulator (DP-DPMZM) is used to generate an orthogonally polarized single RF/IF signal and local oscillator (LO) modulation sideband without an optical carrier. The optical phase difference between the two sidebands can be controlled by controlling a DC voltage applied to a LiNbO3 electro-optic phase modulator that is connected after the DP-DPMZM. Beating between the two sidebands at a photodetector generates an RF/IF signal with a phase equal to the optical phase difference between the IF/RF signal and LO sidebands. The dual-function photonic microwave signal processor has a wide bandwidth and does not require a precise control of the laser wavelength. Experimental results demonstrate that a flat >-3 dB down/up conversion efficiency is achieved for an RF signal from 3.5 to 26.5 GHz and for an IF signal from 0.5 to 3 GHz, and a full 360° continuous phase shift of the output IF/RF signal.
Auteurs: Tao Li;Erwin Hoi Wing Chan;Xudong Wang;Xinhuan Feng;Bai-Ou Guan;Jianping Yao;
Apparue dans: IEEE Photonics Journal
Date publication: 02.-2018, volume: 10, issue:1, pages: 1 - 12
Editeur: IEEE
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» BTI Analysis Tool—Modeling of NBTI DC, AC Stress and Recovery Time Kinetics, Nitrogen Impact, and EOL Estimation
Résumé:
A comprehensive modeling framework is presented to predict the time kinetics of negative bias temperature instability stress and recovery during and after dc and ac stresses and also during mixed dc–ac stress. The model uses uncorrelated contributions from the generation of interface and bulk traps and hole trapping in preexisting bulk traps. Ultrafast measured data at different stresses and recovery biases, temperature, duty cycle and frequency, as well as arbitrary time segments with dynamically varying voltage, frequency, and activity are predicted. The role of nitrogen in the gate insulator is explained. End-of-life degradation is determined under dc and ac use conditions.
Auteurs: Narendra Parihar;Nilesh Goel;Subhadeep Mukhopadhyay;Souvik Mahapatra;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 02.-2018, volume: 65, issue:2, pages: 392 - 403
Editeur: IEEE
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» Build a nixie-S style clock without the fuss
Résumé:
STANLEY KUBRICK'S 1968 SCIENCE FICTION FILM 2001: A Space Odyssey still stands up pretty well. But there's a telling anachronism in the scene where scientists visit a monolith that's been uncovered on the moon. On their lunar shuttle's control panel, there are numerical indicator lights clearly made with cold-cathode displays, also known as Nixie tubes. This technology was in vogue during the mid-1950s but fell out of favor in the 1970s. Nixie tubes still enjoy a following among enthusiasts of retro technology. I've sometimes been tempted to build a Nixie-tube clock, but the difficulties and expense always put me off. It's hard even to purchase Nixie tubes at this point—especially larger ones-and they require high-voltage driver circuits, which are inherently dangerous. So I was delighted when I stumbled on something designed to mimic the appearance of Nixie tubes without the complications-something its designer calls a "Lixie display."
Auteurs: David Schneider;
Apparue dans: IEEE Spectrum
Date publication: 02.-2018, volume: 55, issue:2, pages: 19 - 20
Editeur: IEEE
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» Cache-Enabled Physical Layer Security for Video Streaming in Backhaul-Limited Cellular Networks
Résumé:
In this paper, we propose a novel wireless caching scheme to enhance the physical layer security of video streaming in cellular networks with limited backhaul capacity. By proactively sharing video data across a subset of base stations (BSs) through both caching and backhaul loading, secure cooperative joint transmission of several BSs can be dynamically enabled in accordance with the cache status, the channel conditions, and the backhaul capacity. Assuming imperfect channel state information (CSI) at the transmitters, we formulate a two-stage non-convex mixed-integer robust optimization problem for minimizing the total transmit power while providing the quality of service and guaranteeing communication secrecy during video delivery, where the caching and the cooperative transmission policy are optimized in an offline video caching stage and an online video delivery stage, respectively. Although the formulated optimization problem turns out to be NP-hard, low-complexity polynomial-time algorithms, whose solutions are globally optimal under certain conditions, are proposed for cache training and video delivery control. Caching is shown to be beneficial as it reduces the data sharing overhead imposed on the capacity-constrained backhaul links, introduces additional secure degrees of freedom, and enables a power-efficient communication system design. Simulation results confirm that the proposed caching scheme achieves simultaneously a low secrecy outage probability and a high power efficiency. Furthermore, due to the proposed robust optimization, the performance loss caused by imperfect CSI knowledge can be significantly reduced when the cache capacity becomes large.
Auteurs: Lin Xiang;Derrick Wing Kwan Ng;Robert Schober;Vincent W. S. Wong;
Apparue dans: IEEE Transactions on Wireless Communications
Date publication: 02.-2018, volume: 17, issue:2, pages: 736 - 751
Editeur: IEEE
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» Caching Meets Millimeter Wave Communications for Enhanced Mobility Management in 5G Networks
Résumé:
One of the most promising approaches to overcoming the uncertainty of millimeter wave (mm-wave) communications is to deploy dual-mode small base stations (SBSs) that integrate both mm-wave and microwave ( $mu text{W}$ ) frequencies. In this paper, a novel approach to analyzing and managing mobility in joint mmwave– $mu text{W}$ networks is proposed. The proposed approach leverages device-level caching along with the capabilities of dual-mode SBSs to minimize handover failures and reduce inter-frequency measurement energy consumption. First, fundamental results on the caching capabilities are derived for the proposed dual-mode network scenario. Second, the impact of caching on the number of handovers (HOs), energy consumption, and the average handover failure (HOF) is analyzed. Then, the proposed cache-enabled mobility management problem is formulated as a dynamic matching game between mobile user equipments (MUEs) and SBSs. The goal of this game is to find a distributed HO mechanism that, under network constraints on HOFs and limited cache sizes, allows each MUE to choose between: 1) executing an HO to a target SBS; 2) being connected to the macrocell base station; or 3) perform a transparent HO by using the cached content. To solve this dynamic matching problem, a novel algorithm is proposed and its convergence to a two-sided dynamically stable HO policy for MUEs and target SBSs is proved. Numerical results corroborate the analytical derivations and show that the proposed solution will significantly reduce both the HOF and energy consumption of MUEs, resulting in an enhanced mobility management for heterogeneous wireless networks with mm-wave capabilities.
Auteurs: Omid Semiari;Walid Saad;Mehdi Bennis;Behrouz Maham;
Apparue dans: IEEE Transactions on Wireless Communications
Date publication: 02.-2018, volume: 17, issue:2, pages: 779 - 793
Editeur: IEEE
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» Calculating the Expected Time to Eradicate HIV-1 Using a Markov Chain
Résumé:
In this study, the expected time required to eradicate HIV-1 completely was found as the conditional absorbing time in a finite state space continuous-time Markov chain model. The Markov chain has two absorbing states: one corresponds to HIV eradication and another representing the possible disaster. This method allowed us to calculate the expected eradication time by solving systems of linear equations. To overcome the challenge of huge dimension of the problem, we applied a novel stop and resume technique. This technique also helped to stop the numerical computation whenever we wanted and continue later from that point until the final result was obtained. Our numerical study showed the dependence of the expected eradication time of HIV on the half-life of the latently infected cells and there agreed with the previous studies. The study predicted that when the half-life of the latent cells varied from 4.6 to 60 months, it took a mean 4.97 to 31.04 years with a corresponding standard deviation of 0.64 to 3.99 years to eradicate the latent cell reservoir. It also revealed the crucial dependence of eradication time on the initial number of latently infected cells.
Auteurs: Narayanan C. Viswanath;
Apparue dans: IEEE/ACM Transactions on Computational Biology and Bioinformatics
Date publication: 02.-2018, volume: 15, issue:1, pages: 60 - 67
Editeur: IEEE
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» Calibration Algorithm for Cross-Track Infrared Sounder Full Spectral Resolution Measurements
Résumé:
The cross-track infrared sounder has been operated in the full spectral resolution (FSR) mode since December 4, 2014. To provide the FSR radiance spectra with a spectral resolution of 0.625 cm−1 for all the three bands, a new calibration algorithm has been developed and implemented for operational uses. The algorithm is an improvement over the previous algorithm that had been operationally used until March 2017. Major changes include the calibration equation, self-apodization correction and resampling matrices, and calibration filter. Compared to the previous algorithm, the improvement reduces the calibration inconsistencies among the nine fields of view and between the forward and reverse interferometer sweep directions by up to 0.5 K, and the differences between observed and simulated spectra by up to 0.4 K.
Auteurs: Yong Han;Yong Chen;
Apparue dans: IEEE Transactions on Geoscience and Remote Sensing
Date publication: 02.-2018, volume: 56, issue:2, pages: 1008 - 1016
Editeur: IEEE
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» Calling Inspector Gadget [Microwave Surfing]
Résumé:
Unless you were away earlier this year on an intergalactic mission, you probably picked up the heavy media buzz around the claim [1] made by an “important government source”: There was an article this week that talked about how you can surveil someone through their phones, through their . . . certainly through their television sets, any number of different ways. And microwaves that turn into cameras, et cetera. So we know that that is just a fact of modern life. So: is it really a fact of modern life that microwaves can spy on you? It depends on the meaning of microwaves. According to the Merriam-Webster Online Dictionary [2], the word means either “a comparatively short electromagnetic wave; especially: one between about one millimeter and one meter in wavelength” or a “microwave oven.”
Auteurs: Rajeev Bansal;
Apparue dans: IEEE Microwave Magazine
Date publication: 02.-2018, volume: 19, issue:1, pages: 12 - 130
Editeur: IEEE
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» Capacity Optimization for Resource Pooling in Virtualized Data Centers with Composable Systems
Résumé:
Recent research trends exhibit a growing imbalance between the demands of tenants’ software applications and the provisioning of hardware resources. Misalignment of demand and supply gradually hinders workloads from being efficiently mapped to fixed-sized server nodes in traditional data centers. The incurred resource holes not only lower infrastructure utilization but also cripple the capability of a data center for hosting large-sized workloads. This deficiency motivates the development of a new rack-wide architecture referred to as the composable system . The composable system transforms traditional server racks of static capacity into a dynamic compute platform. Specifically, this novel architecture aims to link up all compute components that are traditionally distributed on traditional server boards, such as central processing unit (CPU), random access memory (RAM), storage devices, and other application-specific processors. By doing so, a logically giant compute platform is created and this platform is more resistant against the variety of workload demands by breaking the resource boundaries among traditional server boards. In this paper, we introduce the concepts of this reconfigurable architecture and design a framework of the composable system for cloud data centers. We then develop mathematical models to describe the resource usage patterns on this platform and enumerate some types of workloads that commonly appear in data centers. From the simulations, we show that the composable system sustains nearly up to 1.6 times stronger workload intensity than that of traditional systems and it is insensitive to the distribution of workload demands. This demonstrates that this composable system is indeed an effective solution to support cloud data center services.
Auteurs: An-Dee Lin;Chung-Sheng Li;Wanjiun Liao;Hubertus Franke;
Apparue dans: IEEE Transactions on Parallel and Distributed Systems
Date publication: 02.-2018, volume: 29, issue:2, pages: 324 - 337
Editeur: IEEE
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» Car Detection in Aerial Images of Dense Urban Areas
Résumé:
With the ever-increasing demand in the analysis and understanding of aerial images in order to remotely recognize targets, this paper introduces a robust system for the detection and localization of cars in images captured by air vehicles and satellites. The system adopts a sliding-window approach. It compromises a window-evaluation and a window-classification subsystems. The performance of the proposed framework was evaluated on the Vaihingen dataset. Results demonstrate its superiority to the state of the art.
Auteurs: Mohamed ElMikaty;Tania Stathaki;
Apparue dans: IEEE Transactions on Aerospace and Electronic Systems
Date publication: 02.-2018, volume: 54, issue:1, pages: 51 - 63
Editeur: IEEE
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» Carrier Mobility Enhancement by Applying Back-Gate Bias in Ge-on-Insulator MOSFETs
Résumé:
In this letter, we comprehensively study the carriers’ mobility and the effect of back-gate bias ( ${V} _{textsf {bg}}$ ) in Ge-on-insulator (GeOI) MOSFETs with various working modes, including accumulation mode (AM) nMOSFET, inversion mode (IM) nMOSFET, AM pMOSFET, and IM pMOSFET. The results show that the AM nMOSFETs and pMOSFETs have higher drain currents and carriers’ mobility. The electron mobility increases under positive ${V} _{textsf {bg}}$ and decreases under negative ${V} _{textsf {bg}}$ . While the hole mobility has the opposite ${V} _{textsf {bg}}$ dependence. The carriers’ mobility of AM MOSFETs is proved to benefit more from ${V} _{textsf {bg}}$ due to the increase of carriers’ densities. The peak mobility enhancements of more than 100% for holes and 35% for electrons are achieved in GeOI MOSFETs by applying ${V} _{textsf {bg}}$ .
Auteurs: Wangran Wu;Heng Wu;Jingyun Zhang;Mengwei Si;Yi Zhao;Peide D. Ye;
Apparue dans: IEEE Electron Device Letters
Date publication: 02.-2018, volume: 39, issue:2, pages: 176 - 179
Editeur: IEEE
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» Causality Countermeasures for Anomaly Detection in Cyber-Physical Systems
Résumé:
The problem of attack detection in cyber-physical systems is considered in this paper. Transfer-entropy-based causality countermeasures are introduced for both sensor measurements and innovation sequences, which can be evaluated in a data-driven fashion without relying on a model of the underlying dynamic system. The relationships between the countermeasures and the system parameters as well as the noise statistics are investigated, based on which conditions that guarantee the time convergence of the countermeasures are obtained. The effectiveness of the transfer entropy countermeasures in attack detection is evaluated via theoretical analysis, numerical demonstrations, as well as comparative simulations with classical $boldsymbol {chi ^2}$ detectors. Four types of attacks are considered: denial-of-service, replay, innovation-based deception, and data injection attacks. Abnormal behavior of the transfer entropy can be observed after the occurrence of each of these attacks.
Auteurs: Dawei Shi;Ziyang Guo;Karl Henrik Johansson;Ling Shi;
Apparue dans: IEEE Transactions on Automatic Control
Date publication: 02.-2018, volume: 63, issue:2, pages: 386 - 401
Editeur: IEEE
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» CCL: Cross-modal Correlation Learning With Multigrained Fusion by Hierarchical Network
Résumé:
Cross-modal retrieval has become a highlighted research topic for retrieval across multimedia data such as image and text. A two-stage learning framework is widely adopted by most existing methods based on deep neural network (DNN): The first learning stage is to generate separate representation for each modality and the second learning stage is to get the cross-modal common representation. However the existing methods have three limitations: 1) In the first learning stage they only model intramodality correlation but ignore intermodality correlation with rich complementary context. 2) In the second learning stage they only adopt shallow networks with single-loss regularization but ignore the intrinsic relevance of intramodality and intermodality correlation. 3) Only original instances are considered while the complementary fine-grained clues provided by their patches are ignored. For addressing the above problems this paper proposes a cross-modal correlation learning (CCL) approach with multigrained fusion by hierarchical network and the contributions are as follows: 1) In the first learning stage CCL exploits multilevel association with joint optimization to preserve the complementary context from intramodality and intermodality correlation simultaneously. 2) In the second learning stage a multitask learning strategy is designed to adaptively balance the intramodality semantic category constraints and intermodality pairwise similarity constraints. 3) CCL adopts multigrained modeling which fuses the coarse-grained instances and fine-grained patches to make cross-modal correlation more precise. Comparing with 13 state-of-the-art methods on 6 widely-used cross-modal datasets the experimental results show our CCL approach achieves the best performance.
Auteurs: Yuxin Peng;Jinwei Qi;Xin Huang;Yuxin Yuan;
Apparue dans: IEEE Transactions on Multimedia
Date publication: 02.-2018, volume: 20, issue:2, pages: 405 - 420
Editeur: IEEE
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» Ceramics for the Future: Advanced Millimeter-Wave Multilayer Multichip Module Integration and Packaging
Résumé:
The advantages of higher-frequency operation, such as wider bandwidth and finer spatial and temporal resolution, have led to increased interest in the use of millimeter-waves (mmWs) in both commercial and military applications-covering, in particular, areas ranging from high-speed wireless communication (including wireless local area networking, wireless gigabit communication, sensor networks, and fifth-generation systems) to space science to security [1]-[5]. For biological and health applications, mmW imaging offers a superior, safer, and lower-cost alternative to conventional techniques [6], [7].
Auteurs: Kamal K. Samanta;
Apparue dans: IEEE Microwave Magazine
Date publication: 02.-2018, volume: 19, issue:1, pages: 22 - 35
Editeur: IEEE
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» Certificateless Searchable Public Key Encryption Scheme for Industrial Internet of Things
Résumé:
With the widespread adoption of Internet of Things and cloud computing in different industry sectors, an increasing number of individuals or organizations are outsourcing their Industrial Internet of Things (IIoT) data in the cloud server to achieve cost saving and collaboration (e.g., data sharing). However, in this environment, preserving the privacy of data remains a key challenge and inhibiting factor to an even wider adoption of IIoT in the cloud environment. To mitigate these issues, in this paper, we design a new secure channel-free certificateless searchable public key encryption with multiple keywords scheme for IIoT deployment. We then demonstrate the security of the scheme in the random oracle model against two types of adversaries, where one adversary is given the power to choose a random public key instead of any user's public key and another adversary is allowed to learn the system master key. In the presence of these types of adversaries, we evaluate the performance of the proposed scheme and demonstrate that it achieves (computational) efficiency with low communication cost.
Auteurs: Mimi Ma;Debiao He;Neeraj Kumar;Kim-Kwang Raymond Choo;Jianhua Chen;
Apparue dans: IEEE Transactions on Industrial Informatics
Date publication: 02.-2018, volume: 14, issue:2, pages: 759 - 767
Editeur: IEEE
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» Changes Impacting Our Publications [From the Editor's Desk]
Résumé:
Discusses the IEEE PSPB rules regarding the republication of papers in IEEE Xplore and assesses its impact on IAS publications.
Auteurs: Lanny Floyd;
Apparue dans: IEEE Industry Applications Magazine
Date publication: 02.-2018, volume: 24, issue:1, pages: 3 - 5
Editeur: IEEE
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» Changing Household Energy Usage: The Downsides of Incentives and How to Overcome Them
Résumé:
To combat climate change, the Intergovernmental Panel for Climate Change (IPCC) calculated that greenhouse gas emissions in the energy domain should be reduced by 90%, compared to 2010 emissions, between the years 2040 and 2070. In Europe, residential households consume about a quarter of total energy used (excluding the energy that is embodied in products). To contribute to the carbon emission reduction targets set by the IPCC , households need to reduce their fossilenergy use.
Auteurs: Ellen van der Werff;John Thogersen;Wandi Bruine de Bruin;
Apparue dans: IEEE Power and Energy Magazine
Date publication: 02.-2018, volume: 16, issue:1, pages: 42 - 48
Editeur: IEEE
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» Changing the Electrical Safety Culture
Résumé:
This paper examines what it takes to improve the electrical safety culture in an organization. First, the components of a culture are examined and how any culture comes to be the norm is reviewed. Second, examples are given on how culture has already changed significantly by contrasting past and present work practices in electrical safety. Third, suggestions for concrete ways to make future improvements in electrical safety cultures are provided. A fundamental argument in this paper is that culture represents the sum total of what is commonly acceptable without examination. The culture is also driven by everyday observation and experience. In order to change the culture, there must be a redefinition of what is acceptable, followed by visible changes that everyone can experience and observe. Management owns the resulting culture, whether good or bad, because it sets standards for what behaviors are tolerable and acceptable. Therefore, the future of electrical safety will depend on how well management understands the risk and consequences of electrical work, and their responsibility in shaping and owning electrical safety policies and practices. Key elements addressed in this paper include management ownership of the electrical safety culture, busting the myth of “overcompliance,” integrating cultural drivers into an overall electrical safety program, and addressing the more difficult aspects of human performance in a fair manner.
Auteurs: Daryld Ray Crow;Danny P. Liggett;Mark A. Scott;
Apparue dans: IEEE Transactions on Industry Applications
Date publication: 02.-2018, volume: 54, issue:1, pages: 808 - 814
Editeur: IEEE
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» Channel Capacity of Wavelength Division Multiplexing-Based Brillouin Optical Time Domain Sensors
Résumé:
We propose and demonstrate a novel WDM-based Brillouin optical time domain analysis (BOTDA) sensor using Brillouin loss configuration, and theoretically analyze channel capacity of WDM-based brillouin optical time domain reflectometry (BOTDR) and BOTDA sensors by considering the fiber dispersion and nonlinear effects in sensing fibers. A three-wavelength WDM-based BOTDA senor is experimentally validated in the distributed temperature measurement of a 23-km-long standard telecom fiber (SMF-28), demonstrating an electrical signal-to-noise ratio enhancement of 9.2 dB. The numerical calculation results of the channel capacity of WDM-based Brillouin optical time domain sensors show that, when compared with the conventional single-wavelength BOTDR and BOTDA sensors, 11-wavelength BOTDR and BOTDA sensor using large effective area fiber can respectively achieve 8.4 and 20.8 dB signal-noise-ratio improvement (SNRI), and 7-wavelength BOTDR and BOTDA sensor using SMF-28 can respectively achieve 7.2 B and 16.9 dB SNRI without evident spatial resolution degradation and nonlinear impairment.
Auteurs: Zelin Zhang;Yuangang Lu;Yunqin Zhao;
Apparue dans: IEEE Photonics Journal
Date publication: 02.-2018, volume: 10, issue:1, pages: 1 - 15
Editeur: IEEE
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» Channel Estimation for mmWave MIMO With Transmitter Hardware Impairments
Résumé:
This letter considers the problem of channel estimation for millimeter wave (mmWave) multiple-input multiple-output systems under a transmitter impairments model. Specifically, taking the transmitter hardware impairments into account, the performance of conventional pilots-based channel estimation scheme will be degraded due to the destroyed training pilots. By exploiting the sparsity of mmWave channel in the angular domain, a new channel estimation algorithm based on the Bayesian compressive sensing (BCS) and least square estimation (LSE) is proposed. First, the expectation maximization algorithm is presented to solve the BCS problem, and the refined measurement matrix and the support of the channel vector are obtained. Next, the channel gain coefficients are estimated by using the LSE. Simulation results show that the proposed algorithm can achieve better performance compared with the conventional BCS and orthogonal matching pursuit algorithm.
Auteurs: Yue Wu;Yuantao Gu;Zhaocheng Wang;
Apparue dans: IEEE Communications Letters
Date publication: 02.-2018, volume: 22, issue:2, pages: 320 - 323
Editeur: IEEE
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» Chaotic Constellation Mapping for Physical-Layer Data Encryption in OFDM-PON
Résumé:
A physical-layer encryption scheme is proposed and experimentally demonstrated in orthogonal frequency division multiplexing passive optical network (OFDM-PON). In the proposed multifold encryption scheme, quadratic-amplitude modulation (QAM) symbols are scrambled and distributed onto the complex plane independently. The dynamic parameters of constellation shifting are generated by a 3-D hyper digital chaos, in which a key space of ~10162 is created to enhance the security level of OFDM data encryption during transmission. An encrypted data transmission of 9.4-Gb/s, 16-QAM optical OFDM signals is successfully demonstrated over 20-km standard single-mode fiber.
Auteurs: Amber Sultan;Xuelin Yang;Adnan A. E. Hajomer;Weisheng Hu;
Apparue dans: IEEE Photonics Technology Letters
Date publication: 02.-2018, volume: 30, issue:4, pages: 339 - 342
Editeur: IEEE
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» Characteristic Impedance Control for Branch-Line Coupler Design
Résumé:
This letter presents a new approach to control impedance for branch-line coupler (BLC) design. With the proposed method, the highest impedance of the two-section BLC can be set to a realistic value (below $100~Omega$ ), so that it can be implemented with ordinary planar technology. The measured results are compared with the simulated results to validate the proposed theory and design approach.
Auteurs: Qiuyi Wu;Yimin Yang;Ying Wang;Xiaowei Shi;Ming Yu;
Apparue dans: IEEE Microwave and Wireless Components Letters
Date publication: 02.-2018, volume: 28, issue:2, pages: 123 - 125
Editeur: IEEE
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» Characteristic Mode Assisted Placement of Antennas for the Isolation Enhancement
Résumé:
In this letter, the isolation between onboard antennas is investigated using characteristic mode analysis, which provides an intuitive insight for the antenna placement on large platforms. An analytical expression of the relationship between the platform modal excitation coefficient and the platform modal charge is derived under the condition of a coaxial feeding mechanism. It is revealed that the deployment position that leads to a maximum isolation is indicated by the platform modal charge. Based on this finding, a simple and efficient method for antenna placement on aircraft-like platforms is developed to enhance the isolation. Two examples with vertically polarized blade antennas are presented, in which two or three blade antennas can be deployed on the platforms. Both the numerical and experimental results show that the isolation is increased remarkably by the proposed method.
Auteurs: Donglin Su;Zhao Yang;Qi Wu;
Apparue dans: IEEE Antennas and Wireless Propagation Letters
Date publication: 02.-2018, volume: 17, issue:2, pages: 251 - 254
Editeur: IEEE
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» Characteristics and Performances of a 100-W Hall Thruster for Microspacecraft
Résumé:
In this paper, we examine the characteristics of the ISCT100 thruster, a miniature xenon-fueled 100-W permanent magnet Hall thruster (HT) suited for microspacecraft propulsion. The impact of the thruster design upon discharge behavior, ion beam properties, and performances is examined as for two discharge channel geometries as well as two values of the magnetic field strength. Thrust, specific impulse, and efficiency obtained between 50 and 200 W are compared with the ones of other low-power HTs.
Auteurs: Stéphane Mazouffre;Lou Grimaud;
Apparue dans: IEEE Transactions on Plasma Science
Date publication: 02.-2018, volume: 46, issue:2, pages: 330 - 337
Editeur: IEEE
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» Characteristics of Large Antennas with Radomes [Antenna Applications Corner]
Résumé:
Radomes for large ground antennas used in satellite communications have been analyzed extensively in the past, but little work related to the practical evaluation of radio-frequency (RF) performance has been reported. This article summarizes the results of observations conducted on three different kinds of antennas with radomes operating at the X and Ka frequencies.
Auteurs: Roland William Schwerdtfeger;
Apparue dans: IEEE Antennas and Propagation Magazine
Date publication: 02.-2018, volume: 60, issue:1, pages: 94 - 103
Editeur: IEEE
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» Characteristics of Recessed-Gate TFETs With Line Tunneling
Résumé:
In this paper, we propose a recessed-gate tunneling field-effect transistor (TFET) to improve the on current of TFETs by increasing the tunnel area with line tunneling. We investigate the effects of the recessed-body thickness and the doping level on the device performance. For optimal device structures, our proposed n-TFET reaches $1.44 times 10^{-6}$ A/ $mu text{m}$ of on current and $3.22 times 10^{9}$ ON/ OFF current ratio. A minimum subthreshold swing SS $_{{textsf {min}}} = 28.3$ mV/dec and an average swing SS $_{{textsf {avg}}} = 59.8$ mV/dec over seven orders of drain current are achieved. In addition, complementary TFET inverters show good noise margins of $textsf {NM}_{H} = 65$ mV (38.5 % $V_{{textsf {DD}}}$ ) and NM $_{L} = 77$ mV (32.5 % $V_{{textsf {DD}}}$ ) and also a high voltage gain even at $V_{{textsf {DD}}} = 0.2$ V.
Auteurs: Jyi-Tsong Lin;Tzu-Chi Wang;Wei-Han Lee;Chih-Ting Yeh;Stefan Glass;Qing-Tai Zhao;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 02.-2018, volume: 65, issue:2, pages: 769 - 775
Editeur: IEEE
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» Characterization and Modeling of Tissue Thermal Conductivity During an Electrosurgical Joining Process
Résumé:
Electrosurgical vessel joining is commonly performed in surgical procedures to maintain hemostasis. This process requires elevated temperature to denature the tissue and while compression is applied, the tissue can be joined together. The elevated temperature can cause thermal damages to the surrounding tissues. In order to minimize these damages, it is critical to understand how the tissue properties change and how that affects the thermal spread. The purpose of this study is to investigate the changes of tissue thermal conductivity and how the changes correlate to thermal dose during the joining process. We propose a hybrid method combining experimental measurement with inverse heat transfer analysis to determine thermal conductivity of thin tissue sample. Porcine aorta arterial tissues were used to investigate tissue thermal conductivity with variable thermal dose. Different joining times were used to create different amounts of thermal dose. A 36% decrease in tissue thermal conductivity was found when the thermal dose reaches the threshold for second-degree burn. When thermal dose is beyond the threshold of third-degree burn, the tissue thermal conductivity does not decrease significantly. A regression model was also developed and can be used to predict tissue thermal conductivity based on the thermal dose.
Auteurs: Che-Hao Yang;Wei Li;Roland K. Chen;
Apparue dans: IEEE Transactions on Biomedical Engineering
Date publication: 02.-2018, volume: 65, issue:2, pages: 365 - 370
Editeur: IEEE
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» Characterization of a Terbium-Activated Gadolinium Oxysulfide Plastic Optical Fiber Sensor in Photons and Protons
Résumé:
A characterization study was carried out to determine if a novel, millimeter sized Terbium-activated Gadolinium Oxysulfide optical fibre detector has potential for future use in proton dosimetry. Preliminary studies employed a Theratronics Theratron 780C Cobalt-60 unit and were used to determine nominal dose response, field size response and Čerenkov contributions in 1.25-MeV gamma radiation. More extensive testing was done using 74 MeV-protons produced in the TRIUMF 500-MeV cyclotron facility examining raw Bragg peak, spread out Bragg peak, dose response, and Čerenkov signal. The detector was low-cost and easily assembled; it showed excellent sensitivity, signal to noise ratio, and reproducibility. Quenching at high linear energy transfer was severe. Additional investigations are needed to further explore Čerenkov-only depth-dose curves, signal detection at the extreme distal end of the Bragg peak, and possible sensitivity to neutrons.
Auteurs: Crystal Penner;Cornelia Hoehr;Sinead O’Keeffe;Peter Woulfe;Cheryl Duzenli;
Apparue dans: IEEE Sensors Journal
Date publication: 02.-2018, volume: 18, issue:4, pages: 1513 - 1519
Editeur: IEEE
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» Characterization of Intermodulation Distortion in Reconfigurable Liquid Metal Antennas
Résumé:
The intermodulation distortion produced by passive and tunable liquid metal (LM) antennas is investigated. Four kinds of monopoles, including a passive copper monopole, a varactor-tuned copper monopole, a passive LM monopole, and a tunable LM monopole using electrochemically controlled capillarity (ECC), are compared for their linearity and power-handling capabilities. Linearity is assessed using a two-tone distortion test, in which two fundamental tones close in frequency result in third-order intermodulation tones at frequencies above and below the original tones separated by the frequency difference. The passive LM monopole has comparable linearity to the passive copper monopole, while the linearity of the ECC-tuned LM monopole is at least 40 dB better than that of the active varactor monopole. The reconfigurable LM antenna also handles higher power (31 dBm) before failure than does the active varactor-tuned antenna (24 dBm).
Auteurs: Meng Wang;Ian M. Kilgore;Michael B. Steer;Jacob J. Adams;
Apparue dans: IEEE Antennas and Wireless Propagation Letters
Date publication: 02.-2018, volume: 17, issue:2, pages: 279 - 282
Editeur: IEEE
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» Characterizations of Enhancement-Mode Double Heterostructure GaN HEMTs With Gate Field Plates
Résumé:
With the purpose to increase the threshold voltage of the enhancement mode GaN high-electron mobility transistors, we fabricated devices with gate field plates on the p-GaN/AlGaN/GaN/AlGaN double heterostructures. We observed an existence of a subthreshold region from the current–voltage transfer curves. The threshold voltage of the device extracted based on linear extrapolation method is much higher than that of a typical device without a gate field plate. We investigated electrical properties based on carrier distributions with the influence of gate electric field at different channel regions.
Auteurs: Chun-Hsun Lee;Wei-Ren Lin;Yu-Hsuan Lee;Jian-jang Huang;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 02.-2018, volume: 65, issue:2, pages: 488 - 492
Editeur: IEEE
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» Characterizing Antennas in the Time and Frequency Domains [Education Corner]
Résumé:
The antenna definitions standard [1] currently has no terms that describe antenna performance in the time domain, possibly due to the complexity of the equations. However, if the antenna equations are expressed using quantities related to the square root of power, then simple expressions are obtained that are valid in both the frequency and time domains. This leads to a number of new terms that should be considered for inclusion in the next revision of the standard. Doing so would provide a common language for discussing antenna performance in the time domain. It would also add phase information to common frequency-domain terms, such as antenna gain and radar cross section.
Auteurs: Everett G. Farr;
Apparue dans: IEEE Antennas and Propagation Magazine
Date publication: 02.-2018, volume: 60, issue:1, pages: 106 - 110
Editeur: IEEE
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» Characterizing Engineering Learners’ Preferences for Active and Passive Learning Methods
Résumé:
This paper studies electrical engineering learners’ preferences for learning methods with various degrees of activity. Less active learning methods such as homework and peer reviews are investigated, as well as a newly introduced very active (constructive) learning method called “slectures,” and some others. The results suggest that graduate students’ perception of the usefulness of the activity increases with its level of activity. For undergraduate students, an increased perception of the usefulness of the activity was observed for lightly active but structured learning methods. Group-based analysis focusing on two types of learners, defined as “instructor-dependent” and “instructor-independent” according to their perception of the usefulness of the classroom lectures, was also performed. The results suggest that instructor-independent learners may benefit more from active learning methods than instructor-dependent learners. For example, instructor-independent undergraduate learners were found to perceive the homework assignment as being more useful than the lectures. Such a preference was not seen in the average group data. In fact, no learning method was found to be perceived as more useful than the lectures, on average. Thus this paper illustrates the pertinence of group-based data analysis.
Auteurs: Alejandra J. Magana;Camilo Vieira;Mireille Boutin;
Apparue dans: IEEE Transactions on Education
Date publication: 02.-2018, volume: 61, issue:1, pages: 46 - 54
Editeur: IEEE
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» Characterizing Privacy Risks of Mobile Apps with Sensitivity Analysis
Résumé:
Given the emerging concerns over app privacy-related risks, major app distribution providers (e.g., Microsoft) have been exploring approaches to help end users to make informed decision before installation. This is different from existing approaches of simply trusting users to make the right decision. We build on the direction of risk rating as the way to communicate app-specific privacy risks to end users. To this end, we propose to use sensitivity analysis to infer whether an app requests sensitive on-device resources/data that are not required for its expected functionality. Our system, Privet, addresses challenges in efficiently achieving test coverage and automated privacy risk assessment. Finally, we evaluate Privet with 1,000 Android apps released in the wild.
Auteurs: Li Lyna Zhang;Chieh-Jan Mike Liang;Zhao Lucis Li;Yunxin Liu;Feng Zhao;Enhong Chen;
Apparue dans: IEEE Transactions on Mobile Computing
Date publication: 02.-2018, volume: 17, issue:2, pages: 279 - 292
Editeur: IEEE
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» Charging Behavior of Users Utilizing Battery Electric Vehicles and Extended Range Electric Vehicles Within the Scope of a Field Test
Résumé:
Electric vehicles (EVs) and their application raise new questions and demands. Accordingly, the charging process of EVs is a novelty in everyday life when using such vehicles. This paper presents results of user charging behavior within a field test. In the field test, 500 people with above average yearly mileage took part in integrating the vehicles into their everyday lives. For the results of this paper, the charging behavior of 200 test people is taken into account. The differences in user behavior between battery electric vehicles (BEVs) and extended range electric vehicles (EREVs) are discussed. The results indicate that there are various opportunities for grid services based on EVs, as the vehicles are connected or parked close to a charging station the majority of the time. Moreover, the results also show deviating user behavior for the BEVs and EREVs.
Auteurs: Philip Karl-Heinz Dost;Philipp Spichartz;Constantinos Sourkounis;
Apparue dans: IEEE Transactions on Industry Applications
Date publication: 02.-2018, volume: 54, issue:1, pages: 580 - 590
Editeur: IEEE
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» Chessboard AMC Surface Based on Quasi-Fractal Structure for Wideband RCS Reduction
Résumé:
A chessboard artificial magnetic conductor surface based on the quasi-fractal structure is proposed for wideband radar cross-section (RCS) reduction. The chessboard configuration is formed by two different cells with 180° ± 37° phase difference over more than 90% frequency bandwidth. The quasi-fractal structure is utilized to achieve the wideband and compact characteristics. Monostatic and bistatic RCS of the proposed chessboard surface are analyzed, and the results are compared with those of equal-sized perfect electric conductor ground plane. Because the scattered fields of the chessboard surface are redirected toward four quadrants, a remarkable RCS reduction of 10 dB can be realized from 5.4 to 14.2 GHz. Measured results of the fabricated prototype satisfactorily agree with the simulated ones.
Auteurs: Jingjing Xue;Wen Jiang;Shuxi Gong;
Apparue dans: IEEE Antennas and Wireless Propagation Letters
Date publication: 02.-2018, volume: 17, issue:2, pages: 201 - 204
Editeur: IEEE
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» CHIMERA: A Field-Programmable Mixed-Signal IC With Time-Domain Configurable Analog Blocks
Résumé:
This paper presents a field-programmable mixed-signal IC named CHIMERA, for low-cost and rapid prototyping of mixed-signal systems. The proposed IC implements field-programmable analog functions with time-domain configurable analog blocks (TCABs). A single TCAB can be programmed to various analog circuits, including a time-to-digital converter, digitally-controlled oscillator, digitally-controlled delay cell, digital pulse-width modulator, and phase interpolator. The TCABs convey and process analog information using the frequency, pulse width, delay, or phase of digital pulses or pulse sequences, rather than using analog voltage or current signals for reduced susceptibility to attenuation and noise. The overall CHIMERA chip also includes arrays of configurable logic blocks (CLBs) and programmable arithmetic logic units (ALUs) for programmable digital functions. By programming the functionality of the TCAB, CLB, and ALU arrays and configuring the interconnects, the chip can implement various mixed-signal systems. A prototype IC fabricated with 65-nm CMOS technology demonstrates the versatile programmability of CHIMERA by being successfully operated as a 1-GHz phase-locked loop with a 12.3-psrms integrated jitter, as a 50-MS/s analog-to-digital converter with a 32.5-dB SNDR, and as a 1.2-to-0.7 V DC–DC converter with 95.5% efficiency.
Auteurs: Yunju Choi;Yoontaek Lee;Seung-Heon Baek;Sung-Joon Lee;Jaeha Kim;
Apparue dans: IEEE Journal of Solid-State Circuits
Date publication: 02.-2018, volume: 53, issue:2, pages: 431 - 444
Editeur: IEEE
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» Chromatic Dispersion, Nonlinear Parameter, and Modulation Format Monitoring Based on Godard's Error for Coherent Optical Transmission Systems
Résumé:
This paper considers Godard's error as signal quality metric to monitor chromatic dispersion (CD), nonlinear parameter, and modulation format in the DSP module of the coherent receivers. We first review a CD monitoring based on Godard's error that can be able to accurately monitor arbitrarily large dispersion values in uncompensated transmission links in combination with frequency domain equalizer, then extend the previous nonlinear parameter monitoring method based on Godard's error by blindly obtaining the optimized value γξp to significantly improve the adaptive capability, and present a simple and effective modulation format monitoring based on Godard's error. Meanwhile, the effectiveness has been experimentally verified in 128-Gb/s PDM-QPSK, 192-Gb/s PDM-8QAM, and 256-Gb/s PDM-16QAM systems.
Auteurs: Lin Jiang;Lianshan Yan;Anlin Yi;Yan Pan;Ming Hao;Wei Pan;Bin Luo;Yves Jaouën;
Apparue dans: IEEE Photonics Journal
Date publication: 02.-2018, volume: 10, issue:1, pages: 1 - 12
Editeur: IEEE
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» Circuit Model Extraction of Parallel-Connected Dual-Passband Coupled-Resonator Filters
Résumé:
In this paper, an analytical coupling matrix extraction scheme is proposed for parallel-connected dual-passband coupled-resonator filters for the first time. Model-based vector fitting technique is adopted to fit the measured responses of the dual-passband filter (DPBF) with a set of rational functions, from which a transversal coupling matrix can be constructed. A novel coupling matrix transformation strategy is developed to transform the transversal coupling matrix to the one corresponding to the topology of a parallel-connected DPBF. A practical filter is used as a test example to demonstrate the extraction procedure. In diagnosing the coupling matrix of the test filter, two kinds of ambiguity problems are discussed in detail and are solved by a perturbation technique. This paper provides a general theoretic framework for computer-aided tuning of a parallel-connected dual-passband or multiple-passband filter.
Auteurs: Ping Zhao;Ke-Li Wu;
Apparue dans: IEEE Transactions on Microwave Theory and Techniques
Date publication: 02.-2018, volume: 66, issue:2, pages: 822 - 830
Editeur: IEEE
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» Circularly Polarized Antenna With Reconfigurable Broadside and Conical Beams Facilitated by a Mode Switchable Feed Network
Résumé:
A pattern-reconfigurable slot-augmented patch antenna is reported that radiates circularly polarized (CP) fields and is switchable between a broadside and a conical radiating mode. Two novel design strategies were adopted to realize these advantageous performance characteristics. First, a mode switchable feed network which includes a set of eight L-probes was developed that facilitates the proper excitation of either the patch’s TM11 or TM21 mode and yields symmetric radiation patterns. Second, their operating bands were made to overlap by augmenting this patch with an annular slot. Consequently, the radiation pattern is easily switched between the broadside and the conical modes within the overlapping operational bandwidths. A prototype was fabricated and tested. The measured results are in good agreement with their simulated values, verifying the design concepts. The measured operating bandwidth, 7.8% from 2.45 to 2.65 GHz, was determined from the overlap of the impedance and axial ratio bandwidths for both modes. The measured realized gain values are stable for both radiating states within this operational bandwidth, the broadside (conical) peak value being 8.5 dBic (5.8 dBic). The CP pattern reconfigurability of this antenna with its favorable performance characteristics makes it an ideal candidate for many RFID and satellite communication applications.
Auteurs: Wei Lin;Hang Wong;Richard W. Ziolkowski;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 02.-2018, volume: 66, issue:2, pages: 996 - 1001
Editeur: IEEE
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» Circulating Current Suppression in Modular Multilevel Converters With Even-Harmonic Repetitive Control
Résumé:
Due to voltage mismatch between phase legs and the dc bus in modular multilevel converters (MMCs), the differential current in MMCs is inherently subjected to circulating even-order harmonics. Repetitive control based active harmonic suppression methods can be adopted to eliminate such harmonics. Nevertheless, conventional repetitive controllers have a relatively slow dynamic response, because all the sampled errors in the past one cycle have to be stored, which causes a response delay for one fundamental period. This paper proposes an improved repetitive control scheme that exclusively copes with even-order harmonics based on the circulating current characteristics of MMC systems. The design details of the even harmonic repetitive control scheme according to the harmonics characteristics are provided. The proposed even-harmonic repetitive control scheme requires halved data memory to store error samplings and the delay introduced by the repetitive controller is also reduced. According to the frequency domain analysis, the even-harmonic repetitive control features faster convergence rate, greater low-frequency gains, higher crossover frequency, and higher tolerance against system frequency deviation, while possessing the same even-order harmonics suppression capability and stability as conventional ones. Simulation and experimental results are presented to show the steady-state harmonics suppression capability, dynamic response, and disturbance tolerance of the proposed even-harmonic repetitive control scheme.
Auteurs: Shunfeng Yang;Peng Wang;Yi Tang;Michael Zagrodnik;Xiaolei Hu;King Jet Tseng;
Apparue dans: IEEE Transactions on Industry Applications
Date publication: 02.-2018, volume: 54, issue:1, pages: 298 - 309
Editeur: IEEE
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» CIS Publication Spotlight [Publication Spotlight]
Résumé:
Presents reviews of recent articles from select IEEE publications.
Auteurs: Haibo He;Jon Garibaldi;Kay Chen Tan;Graham Kendall;Yaochu Jin;Yew Soon Ong;
Apparue dans: IEEE Computational Intelligence Magazine
Date publication: 02.-2018, volume: 13, issue:1, pages: 25 - 27
Editeur: IEEE
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» Cladding Light Stripper of High Average Stripped Power Density With High Attenuation of 39 dB and Low Temperature Rise
Résumé:
We demonstrate a 150-mm long cladding light stripper for kW-level operation with high attenuation and low temperature rising. The first 100 mm of the device was designed based on theoretical simulation to achieve uniform extraction of the high-power scattered cladding light and it was constructed by self-developed experimental device for continuous gradient chemical etching. While in the last 50 mm, we reduced the cladding diameter from 400 to 65 μm and then roughed the surface to extract the residual low NA cladding light more efficiently. The power handling capability of this design was tested up to 1.01 kW for an hour stably without causing any damage. The cladding light stripper achieved a high attenuation of 39 dB and a low temperature elevation of 0.05 °C/ input-Watt under the condition of air cooling. The maximum temperature on the surface of the device was only 78.5 °C with an average stripped power density of 7.156 × 106 W/m2. To the best of our knowledge, the cladding light stripper reported here has the highest average stripped power density and attenuation coefficient without compromising temperature performance. This cladding light stripper is well suitable for application in multikilowatts class fiber lasers.
Auteurs: Shuzhen Zou;Han Chen;Jingyuan Zhang;Haijuan Yu;Zhiyan Zhang;Jing Sun;Xuechun Lin;
Apparue dans: IEEE Photonics Journal
Date publication: 02.-2018, volume: 10, issue:1, pages: 1 - 10
Editeur: IEEE
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» Clarifying Trust in Social Internet of Things
Résumé:
A social approach can be exploited for the Internet of Things (IoT) to manage a large number of connected objects. These objects operate as autonomous agents to request and provide information and services to users. Establishing trustworthy relationships among the objects greatly improves the effectiveness of node interaction in the social IoT and helps nodes overcome perceptions of uncertainty and risk. However, there are limitations in the existing trust models. In this paper, a comprehensive model of trust is proposed that is tailored to the social IoT. The model includes ingredients such as trustor, trustee, goal, trustworthiness evaluation, decision, action, result, and context. Building on this trust model, we clarify the concepts of trust in the social IoT in five aspects such as: 1) mutuality of trustor and trustee; 2) inferential transfer of trust; 3) transitivity of trust; 4) trustworthiness update; and 5) trustworthiness affected by dynamic environment. With network connectivities that are from real-world social networks, a series of simulations are conducted to evaluate the performance of the social IoT operated with the proposed trust model. An experimental IoT network is used to further validate the proposed trust model.
Auteurs: Zhiting Lin;Liang Dong;
Apparue dans: IEEE Transactions on Knowledge and Data Engineering
Date publication: 02.-2018, volume: 30, issue:2, pages: 234 - 248
Editeur: IEEE
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» Classification and Discrimination Among Winding Mechanical Defects, Internal and External Electrical Faults, and Inrush Current of Transformer
Résumé:
In this paper, the mechanical faults of transformers including the winding radial deformation and axial displacement on 1.6 MVA transformer winding are investigated. Then, by estimating the parameters of the detailed model of this transformer winding in MATLAB software and changing these parameters in a manner that is proportional to the mechanical defects in electro-magnetic transients program software, the sampled differential current of the transformer is extracted for each disturbance. Next, the internal and external electrical faults and inrush current of the transformer are simulated. Afterwards, these signals are analyzed using maximal overlap discrete wavelet transform with Daubechies4 wavelet function, and their features are extracted. These extracted features are considered for training the classifiers of Decision Tree and artificial neural network. According to the simulation results, the proposed procedure is capable of classifying and discriminating among winding mechanical defects, internal and external electrical faults, and inrush current with a good accuracy that is the main novelty of this paper in comparison to other published works, which are limited to classifying only some of the mentioned faults.
Auteurs: Sajad Bagheri;Zahra Moravej;Gevork B. Gharehpetian;
Apparue dans: IEEE Transactions on Industrial Informatics
Date publication: 02.-2018, volume: 14, issue:2, pages: 484 - 493
Editeur: IEEE
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» Classification of Hyperspectral Imagery Using a New Fully Convolutional Neural Network
Résumé:
With success of convolutional neural networks (CNNs) in computer vision, the CNN has attracted great attention in hyperspectral classification. Many deep learning-based algorithms have been focused on deep feature extraction for classification improvement. In this letter, a novel deep learning framework for hyperspectral classification based on a fully CNN is proposed. Through convolution, deconvolution, and pooling layers, the deep features of hyperspectral data are enhanced. After feature enhancement, the optimized extreme learning machine (ELM) is utilized for classification. The proposed framework outperforms the existing CNN and other traditional classification algorithms by including deconvolution layers and an optimized ELM. Experimental results demonstrate that it can achieve outstanding hyperspectral classification performance.
Auteurs: Jiaojiao Li;Xi Zhao;Yunsong Li;Qian Du;Bobo Xi;Jing Hu;
Apparue dans: IEEE Geoscience and Remote Sensing Letters
Date publication: 02.-2018, volume: 15, issue:2, pages: 292 - 296
Editeur: IEEE
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» Classification of State Trajectories in Gene Regulatory Networks
Résumé:
Gene-expression-based phenotype classification is used for disease diagnosis and prognosis relating to treatment strategies. The present paper considers classification based on sequential measurements of multiple genes using gene regulatory network (GRN) modeling. There are two networks, original and mutated, and observations consist of trajectories of network states. The problem is to classify an observation trajectory as coming from either the original or mutated network. GRNs are modeled via probabilistic Boolean networks, which incorporate stochasticity at both the gene and network levels. Mutation affects the regulatory logic. Classification is based upon observing a trajectory of states of some given length. We characterize the Bayes classifier and find the Bayes error for a general PBN and the special case of a single Boolean network affected by random perturbations (BNp). The Bayes error is related to network sensitivity, meaning the extent of alteration in the steady-state distribution of the original network owing to mutation. Using standard methods to calculate steady-state distributions is cumbersome and sometimes impossible, so we provide an efficient algorithm and approximations. Extensive simulations are performed to study the effects of various factors, including approximation accuracy. We apply the classification procedure to a p53 BNp and a mammalian cell cycle PBN.
Auteurs: Alireza Karbalayghareh;Ulisses Braga-Neto;Jianping Hua;Edward Russell Dougherty;
Apparue dans: IEEE/ACM Transactions on Computational Biology and Bioinformatics
Date publication: 02.-2018, volume: 15, issue:1, pages: 68 - 82
Editeur: IEEE
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» Clean and Green India: Is Solar Energy the Answer?
Résumé:
Approximately 78% of the world's electricity demand is fulfilled by fossil-fuelbased power plants. Electricity generated from such power plants is costly and often leads to environmental pollution and subsequent health hazards. For example, pollutants from coal combustion cause a variety of respiratory ailments and impact cardiovascular health and the nervous system.
Auteurs: Abhinav Aggarwal;Aman Singhal;Sumit J. Darak;
Apparue dans: IEEE Potentials
Date publication: 02.-2018, volume: 37, issue:1, pages: 40 - 46
Editeur: IEEE
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» Closed-Form Design of Variable Fractional-Delay FIR Filters With Low or Middle Cutoff Frequencies
Résumé:
This paper aims to design variable fractional-delay (VFD) finite-impulse response (FIR) filters with controllable cutoff frequencies. Different with the existing designs, a particular ladder-shaped curve is selected as the desired transfer characteristic of the proposed design. Due to the fact that this particular transfer curve can be well approximated by the convolution windowed spectrum interpolation-based filter, the analytic formula of this filter can be further combined with the cubic spline interpolation and Taylor series expansion, thereby deriving a fast configuration procedure for all tap coefficients in the Farrow structure. Meanwhile, both the fractional delay and the cutoff frequency can be flexibly adjusted by this procedure. By means of theoretical analysis or numerical simulation, we proved that the proposed method is not only suitable to design those VFD FIR filters with low or middle cutoff frequencies, but also concurrently possesses high flexibility in performance adjustment and low complexity in coefficient configuration. Therefore, it is an appropriate supplement of the closed-form WLS design.
Auteurs: Xiangdong Huang;Bo Zhang;Haohua Qin;Wenxing An;
Apparue dans: IEEE Transactions on Circuits and Systems I: Regular Papers
Date publication: 02.-2018, volume: 65, issue:2, pages: 628 - 637
Editeur: IEEE
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» Closed-Loop Continuous Hand Control via Chronic Recording of Regenerative Peripheral Nerve Interfaces
Résumé:
Loss of the upper limb imposes a devastating interruption to everyday life. Full restoration of natural arm control requires the ability to simultaneously control multiple degrees of freedom of the prosthetic arm and maintain that control over an extended period of time. Current clinically available myoelectric prostheses do not provide simultaneous control or consistency for transradial amputees. To address this issue, we have implemented a standard Kalman filter for continuous hand control using intramuscular electromyography (EMG) from both regenerative peripheral nerve interfaces (RPNI) and an intact muscle within non-human primates. Seven RPNIs and one intact muscle were implanted with indwelling bipolar intramuscular electrodes in two rhesus macaques. Following recuperations, function-specific EMG signals were recorded and then fed through the Kalman filter during a hand-movement behavioral task to continuously predict the monkey’s finger position. We were able to reconstruct continuous finger movement offline with an average correlation of $rho = 0.87$ and a root mean squared error (RMSE) of 0.12 between actual and predicted position from two macaques. This finger movement prediction was also performed in real time to enable closed-loop neural control of a virtual hand. Compared with physical hand control, neural control performance was slightly slower but maintained an average target hit success rate of 96.70%. Recalibration longevity measurements maintained consistent average correlation over time but had a significant change in RMSE ( $p <0.05$ ). Additionally, extracted single units varied in amplitude by a factor of +18.65% and −25.85% compared with its mean. This is the first demonst- ation of chronic indwelling electrodes being used for continuous position control via the Kalman filter. Combining these analyses with our novel peripheral nerve interface, we believe that this demonstrates an important step in providing patients with more naturalistic control of their prosthetic limbs.
Auteurs: Philip P. Vu;Zachary T. Irwin;Autumn J. Bullard;Shoshana W. Ambani;Ian C. Sando;Melanie G. Urbanchek;Paul S. Cederna;Cynthia A. Chestek;
Apparue dans: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Date publication: 02.-2018, volume: 26, issue:2, pages: 515 - 526
Editeur: IEEE
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» Cloud Computing-Based Non-Invasive Glucose Monitoring for Diabetic Care
Résumé:
Near infrared photoacoustic spectroscopy is utilized for the development of a continuous non-invasive glucose monitoring system for diabetics. A portable embedded system for taking photoacoustic measurements on tissues to estimate glucose concentration is implemented using field programmable gate array (FPGA). The back-end architecture for high-speed data acquisition and de-noising of photoacoustic measurements operates at 274.823 MHz on a Xilinx Virtex-II Pro FPGA. The glucose measurement technique is verified in vitro on glucose solutions and in vivo on tissues, with photoacoustic signal amplitude varying linearly with sample glucose concentration. A kernel-based regression algorithm using multiple features of the photoacoustic signal is used to estimate glucose concentration from photoacoustic measurements. The calibration algorithm provides a superior performance over previous efforts with a mean absolute relative difference of 8.84% and Clarke Error Grid distribution of 92.86% and 7.14% over Zones A and B of the grid. A cloud computing platform for automated monitoring of blood glucose levels is proposed to enable individuals with diabetes to connect with doctors and caretakers. The developed system is connected to the cloud service using a mobile device, which facilitates implementation of computationally intensive calibration tasks and the storage and analysis of measurement data for treatment and monitoring.
Auteurs: Praful P. Pai;Pradyut K. Sanki;Sudeep K. Sahoo;Arijit De;Sourangshu Bhattacharya;Swapna Banerjee;
Apparue dans: IEEE Transactions on Circuits and Systems I: Regular Papers
Date publication: 02.-2018, volume: 65, issue:2, pages: 663 - 676
Editeur: IEEE
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» Cluster Consensus in Networks of Agents With Weighted Cooperative–Competitive Interactions
Résumé:
This brief concerns a general cooperative–competitive network with weighted interactions, based on which the cluster consensus problem is addressed. A directed network with the weighted cooperative–competitive interactions is classified into three categories: 1) interactively balanced; 2) sub-balanced; and 3) unbalanced digraphs. In interactively balanced or sub-balanced networks, cluster consensus can be achieved, while in interactively unbalanced networks, cluster consensus can be reached in need of additional control inputs exerted on specific pinned agents. Simulations are finally presented to verify the theoretical results.
Auteurs: Jingyuan Zhan;Xiang Li;
Apparue dans: IEEE Transactions on Circuits and Systems II: Express Briefs
Date publication: 02.-2018, volume: 65, issue:2, pages: 241 - 245
Editeur: IEEE
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» Cluster-Based Content Distribution Integrating LTE and IEEE 802.11p with Fuzzy Logic and Q-Learning
Résumé:
There is an increasing demand for distributing a large amount of content to vehicles on the road. However, the cellular network is not sufficient due to its limited bandwidth in a dense vehicle environment. In recent years, vehicular ad hoc networks (VANETs) have been attracting great interests for improving communications between vehicles using infrastructure-less wireless technologies. In this paper, we discuss integrating LTE (Long Term Evolution) with IEEE 802.11p for the content distribution in VANETs. We propose a two-level clustering approach where cluster head nodes in the first level try to reduce the MAC layer contentions for vehicle-tovehicle (V2V) communications, and cluster head nodes in the second level are responsible for providing a gateway functionality between V2V and LTE. A fuzzy logic-based algorithm is employed in the first-level clustering, and a Q-learning algorithm is used in the second-level clustering to tune the number of gateway nodes. We conduct extensive simulations to evaluate the performance of the proposed protocol under various network conditions. Simulation results show that the proposed protocol can achieve 23% throughput improvement in highdensity scenarios compared to the existing approaches.
Auteurs: Celimuge Wu;Tsutomu Yoshinaga;Xianfu Chen;Lin Zhang;Yusheng Ji;
Apparue dans: IEEE Computational Intelligence Magazine
Date publication: 02.-2018, volume: 13, issue:1, pages: 41 - 50
Editeur: IEEE
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» Cluster-Seeking James–Stein Estimators
Résumé:
This paper considers the problem of estimating a high-dimensional vector of parameters ${theta } in mathbb {R}^{n}$ from a noisy observation. The noise vector is independent identically distributed Gaussian with known variance. For a squared-error loss function, the James–Stein (JS) estimator is known to dominate the simple maximum-likelihood (ML) estimator when the dimension $n$ exceeds two. The JS-estimator shrinks the observed vector toward the origin, and the risk reduction over the ML-estimator is greatest for ${theta }$ that lie close to the origin. JS-estimators can be generalized to shrink the data toward any target subspace. Such estimators also dominate the ML-estimator, but the risk reduction is significant only when ${theta }$ lies close to the subspace. This leads to the question: in the absence of prior information about ${theta }$ , how do we design estimators that give significant risk reduction over the ML-estimator for a wide range of ${theta }$ ? In this paper, we propose shrinkage estimators that attempt to infer the structure of ${theta }$ from the observed data in order to construct a good attracting subspace. In particular, the components of the observed vector are separated into clusters, and the elements in each cluster shrunk toward a common attractor. The number of clusters and the attractor for each cluster are determined from the observed vector. We provide concentration results for the squared-error loss and c- nvergence results for the risk of the proposed estimators. The results show that the estimators give significant risk reduction over the ML-estimator for a wide range of ${theta }$ , particularly for large $n$ . Simulation results are provided to support the theoretical claims.
Auteurs: K. Pavan Srinath;Ramji Venkataramanan;
Apparue dans: IEEE Transactions on Information Theory
Date publication: 02.-2018, volume: 64, issue:2, pages: 853 - 874
Editeur: IEEE
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» Clustering Millions of Faces by Identity
Résumé:
Given a large collection of unlabeled face images, we address the problem of clustering faces into an unknown number of identities. This problem is of interest in social media, law enforcement, and other applications, where the number of faces can be of the order of hundreds of million, while the number of identities (clusters) can range from a few thousand to millions. To address the challenges of run-time complexity and cluster quality, we present an approximate Rank-Order clustering algorithm that performs better than popular clustering algorithms (k-Means and Spectral). Our experiments include clustering up to 123 million face images into over 10 million clusters. Clustering results are analyzed in terms of external (known face labels) and internal (unknown face labels) quality measures, and run-time. Our algorithm achieves an F-measure of 0.87 on the LFW benchmark (13 K faces of 5,749 individuals), which drops to 0.27 on the largest dataset considered (13 K faces in LFW + 123M distractor images). Additionally, we show that frames in the YouTube benchmark can be clustered with an F-measure of 0.71. An internal per-cluster quality measure is developed to rank individual clusters for manual exploration of high quality clusters that are compact and isolated.
Auteurs: Charles Otto;Dayong Wang;Anil K. Jain;
Apparue dans: IEEE Transactions on Pattern Analysis and Machine Intelligence
Date publication: 02.-2018, volume: 40, issue:2, pages: 289 - 303
Editeur: IEEE
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» Clustering the Dominant Defective Patterns in Semiconductor Wafer Maps
Résumé:
Identifying defect patterns on wafers is crucial for understanding the root causes and for attributing such patterns to specific steps in the fabrication process. We propose in this paper a system called Dominant Defective Patterns Finder (DDPfinder) that clusters the patterns of defective chips on wafers based on their spatial dependence across wafer maps. Such clustering enables the identification of the dominant defect patterns. DDPfinder clusters chip defects based on how dominant are their spatial patterns across all wafer maps. A chip defect is considered dominant, if: 1) it has a systematic defect pattern arising from a specific assignable cause and 2) it displays spatial dependence across a larger number of wafer maps when compared with other defects. The spatial dependence of a chip defect is determined based on the contiguity ratio of the defect pattern across wafer maps. DDPfinder uses the dominant chip defects to serve as seeds for clustering the patterns of defective chips. This clustering procedure allows process engineers to prioritize their investigation of chip defects based on the dominance status of their clusters. It allows them to pay more attention to the ongoing manufacturing processes that caused the dominant defects. We evaluated the quality and performance of DDPfinder by comparing it experimentally with eight existing clustering models. Results showed marked improvement.
Auteurs: Kamal Taha;Khaled Salah;Paul D. Yoo;
Apparue dans: IEEE Transactions on Semiconductor Manufacturing
Date publication: 02.-2018, volume: 31, issue:1, pages: 156 - 165
Editeur: IEEE
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» CNN-Based Joint Clustering and Representation Learning with Feature Drift Compensation for Large-Scale Image Data
Résumé:
Given a large unlabeled set of images how to efficiently and effectively group them into clusters based on extracted visual representations remains a challenging problem. To address this problem we propose a convolutional neural network (CNN) to jointly solve clustering and representation learning in an iterative manner. In the proposed method given an input image set we first randomly pick k samples and extract their features as initial cluster centroids using the proposed CNN with an initial model pretrained from the ImageNet dataset. Mini-batch k-means is then performed to assign cluster labels to individual input samples for a mini-batch of images randomly sampled from the input image set until all images are processed. Subsequently the proposed CNN simultaneously updates the parameters of the proposed CNN and the centroids of image clusters iteratively based on stochastic gradient descent. We also propose a feature drift compensation scheme to mitigate the drift error caused by feature mismatch in representation learning. Experimental results demonstrate the proposed method outperforms start-of-the-art clustering schemes in terms of accuracy and storage complexity on large-scale image sets containing millions of images.
Auteurs: Chih-Chung Hsu;Chia-Wen Lin;
Apparue dans: IEEE Transactions on Multimedia
Date publication: 02.-2018, volume: 20, issue:2, pages: 421 - 429
Editeur: IEEE
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» COAST: A Cooperative Storage Framework for Mobile Transparent Computing Using Device-to-Device Data Sharing
Résumé:
TC is a promising network computing paradigm that offers an efficient way to make lightweight terminals more powerful, convenient, and secure. TC's execution model separates data storage and application execution, letting terminals load applications from TC servers on demand via the Internet. With this approach, the network's performance significantly affects the TC applications' performance. To enhance TC applications' performance, existing research typically deploys many cache servers on the Internet. However, such caching techniques are not ideal in a mobile environment, where the wireless networks that mobile terminals use for Internet access are expensive and have limited bandwidth. To address this problem, we propose COAST, a cooperative storage framework for MTC. Based on a deviceto- device data-sharing technique, COAST enables a mobile terminal to fetch applications from nearby terminals without accessing the Internet. In this article, we introduce COAST's design, explore the opportunities and challenges of cooperative storage in MTC environments, and identify future research directions.
Auteurs: Jiahui Jin;Junzhou Luo;Yunhao Li;Runqun Xiong;
Apparue dans: IEEE Network
Date publication: 02.-2018, volume: 32, issue:1, pages: 133 - 139
Editeur: IEEE
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» Cobalt could untangle chips' wiring problems
Résumé:
Today's computer chips contain tens of kilometers of copper wiring, built up in 15 or so layers. As the semiconductor industry has shrunk the size of transistors, it has also had to make these interconnects thinner. Today, some wiring layers are so fine that electrical current can actually damage them. And chipmakers are running out of new ways to deal with this problem.
Auteurs: Katherine Bourzac;
Apparue dans: IEEE Spectrum
Date publication: 02.-2018, volume: 55, issue:2, pages: 12 - 13
Editeur: IEEE
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» Codesigned High-Efficiency Single-Layered Substrate Integrated Waveguide Filtering Antenna With a Controllable Radiation Null
Résumé:
This letter proposes a codesigned substrate integrated waveguide (SIW) filtering slot antenna with a controllable radiation null in gain response. The antenna is composed of a single-layered SIW cavity, four metalized posts, a transverse slot, and a vertical SMA connector. Four metalized posts are introduced to split the cavity into two TE 110-mode resonators. The transverse slot is utilized not only to generate radiation, but also to further split one TE110-mode resonator into two half-mode resonators. The bandpass filtering performance is achieved by the couplings between three resonators and the slot. One radiation null has been introduced for selectivity enhancement, and it will occur at the frequency where the slot is placed at about quarter-wavelength from the shorted wall of the cavity. So by changing the position of the slot, frequency of radiation null can be easily controlled, even from one side to another side of the passband. For demonstration, one antenna with a lower out-of-band radiation null and another one with an upper out-of-band radiation null have been designed, fabricated, and measured. Experimental results show that the antennas have the merits of high efficiency, high selectivity, and easily controllable radiation null.
Auteurs: Peng Kai Li;Chang Jiang You;Hong Fang Yu;Xiang Li;Yuan Wang Yang;Jian Hua Deng;
Apparue dans: IEEE Antennas and Wireless Propagation Letters
Date publication: 02.-2018, volume: 17, issue:2, pages: 295 - 298
Editeur: IEEE
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» Collaborative Mobile Edge Computation Offloading for IoT over Fiber-Wireless Networks
Résumé:
Mobile edge computing is envisioned to be a promising paradigm to address the conflict between computationally intensive IoT applications and resource-constrained lightweight mobile devices. However, most existing research on mobile edge computation offloading has only taken the resource allocation between the mobile devices and the MEC servers into consideration, ignoring the huge computation resources in the centralized cloud computing center. To make full use of the centralized cloud and distributed MEC resources, designing a collaborative computation offloading mechanism becomes particularly important. Note that current MEC hosted networks, which mostly adopt the networking technology integrating cellular and core networks, face new challenges of single networking mode, long latency, poor reliability, high congestion, and high energy consumption. Hybrid fiber-wireless networks integrating both low-latency fiber optic and flexible wireless technologies should be a promising solution. Toward this end, we provide in this article a generic fiber-wireless architecture with coexistence of centralized cloud and distributed MEC for IoT connectivity. The problem of cloud-MEC collaborative computation offloading is defined, and a game-theoretic collaborative computation offloading scheme is proposed as our solution. Numerical results corroborate that our proposed scheme can achieve high energy efficiency and scales well as the number of mobile devices increases.
Auteurs: Hongzhi Guo;Jiajia Liu;Huiling Qin;
Apparue dans: IEEE Network
Date publication: 02.-2018, volume: 32, issue:1, pages: 66 - 71
Editeur: IEEE
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» Combination of MIMO Antennas for Handheld Devices [Wireless Corner]
Résumé:
With the development of the fourth-generation (4G) and fifth-generation (5G) wireless systems and the high-data transmission rate requirements, multiple-input, multiple-output (MIMO) antennas are becoming necessary in mobile terminals. Handheld mobile devices support various service standards, such as Wi-Fi, LTE, Wi-Max, personal communications service, and digital cellular systems.
Auteurs: Kumud Ranjan Jha;Satish K. Sharma;
Apparue dans: IEEE Antennas and Propagation Magazine
Date publication: 02.-2018, volume: 60, issue:1, pages: 118 - 131
Editeur: IEEE
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» Combinatorics of Tandem Duplication Random Loss Mutations on Circular Genomes
Résumé:
The tandem duplication random loss operation (TDRL) is an important genome rearrangement operation in metazoan mitochondrial genomes. A TDRL consists of a duplication of a contiguous set of genes in tandem followed by a random loss of one copy of each duplicated gene. This paper presents an analysis of the combinatorics of TDRLs on circular genomes, e.g., the mitochondrial genome. In particular, results on TDRLs for circular genomes and their linear representatives are established. Moreover, the distance between gene orders with respect to linear TDRLs and circular TDRLs is studied. An analysis of the available animal mitochondrial gene orders shows the practical relevance of the theoretical results.
Auteurs: Tom Hartmann;An-Chiang Chu;Martin Middendorf;Matthias Bernt;
Apparue dans: IEEE/ACM Transactions on Computational Biology and Bioinformatics
Date publication: 02.-2018, volume: 15, issue:1, pages: 83 - 95
Editeur: IEEE
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» Combined Effects of Light Illumination and Various Bottom Gate Length on the Instability of Via-Contact-Type Amorphous InGaZnO Thin-Film Transistors
Résumé:
This paper utilizes electrical analyses and a study of physical mechanisms to investigate metal gate structure-dependent performance in amorphous InGaZnO (a-IGZO) thin-film transistors. The effects of different shielding areas between the IGZO layer and metal gate are investigated. In devices with shorter metal gate lengths, an abnormal rise in capacitance at the off-state in capacitance–voltage ( ${C}-{V}$ ) characteristic curves can be observed. This can be attributed to the stronger electric field induced by the edge of the metal gate under bias sweep when the metal gate length is shorter than the IGZO layer length. Light illumination measurements indicate a negative shift in threshold voltage and an increase in subthreshold-leakage current regardless of relative metal gate length. Moreover, negative threshold voltage shift becomes more severe with a more obvious hump in ${C}-{V}$ characteristic curves under back-light illumination of a shorter width device, a phenomenon which has been verified by simulation.
Auteurs: Chung-I Yang;Ting-Chang Chang;Po-Yung Liao;Bo-Wei Chen;Wu-Ching Chou;Guan-Fu Chen;Shin-Ping Huang;Yu-Zhe Zheng;Yu-Xuan Wang;Hsi-Wen Liu;Chien-Yu Lin;Yu-Shan Lin;Ying-Hsin Lu;Shengdong Zhang;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 02.-2018, volume: 65, issue:2, pages: 533 - 536
Editeur: IEEE
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» Combining Static and Dynamic Storage Management for Data Intensive Scientific Workflows
Résumé:
Workflow management systems are widely used to express and execute highly parallel applications. For data-intensive workflows, storage can be the constraining resource: The number of tasks running at once must be artificially limited to not overflow the space available in the filesystem. It is all too easy for a user to dispatch a workflow which consumes all available storage and disrupts all system users. To address these issues, we present a three-tiered approach to workflow storage management: (1) A static analysis algorithm which analyzes the storage needs of a workflow before execution, giving a realistic prediction of success or failure. (2) An online storage management algorithm which accounts for the storage needed by future tasks to avoid deadlock at runtime. (3) A task containment system which limits storage consumption of individual tasks, enabling the strong guarantees of the static analysis and dynamic management algorithms. We demonstrate the application of these techniques on three complex workflows.
Auteurs: Nicholas Hazekamp;Nathaniel Kremer-Herman;Benjamin Tovar;Haiyan Meng;Olivia Choudhury;Scott Emrich;Douglas Thain;
Apparue dans: IEEE Transactions on Parallel and Distributed Systems
Date publication: 02.-2018, volume: 29, issue:2, pages: 338 - 350
Editeur: IEEE
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» Common-Mode Overvoltage Mitigation in a Medium-Voltage Pump Motor Transformerless Drive in a Mining Plant
Résumé:
The mining process requires different types of pumps to transfer fluids from one point to another. In the majority of applications, those pumps are driven by variable speed motor drives in order to improve the energy efficiency of the overall system. Large pumps, ranging from hundreds of kW to a few MW, usually demand medium-voltage converters. Transformerless converters reduce the footprint required for the installation, but give rise to additional concerns related to the common-mode voltages applied to the system and motor. The absence of an isolation transformer along with the use of pulse-width modulated rectifiers are the root causes of this issue. This concern increases when long cables are needed to connect the converter to the motor. This paper presents an application where three-level neutral point clamped transformerless medium-voltage converters are applied to drive motor pumps in a mining plant. The passive filtering techniques used to address the common-mode voltage issues are analyzed through simulations. The proposed solutions are field tested with successful results.
Auteurs: Thiago Morais Parreiras;Brenno Marcus Pereira do Prado;Braz de J. Cardoso Filho;
Apparue dans: IEEE Transactions on Industry Applications
Date publication: 02.-2018, volume: 54, issue:1, pages: 848 - 857
Editeur: IEEE
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» Communication Is Key: How to Discuss Energy and Environmental Issues with Consumers
Résumé:
Scientists are now more certain than ever that humans are responsible for climate change through the combustion of fossil fuels. A recent Global Energy Assessment report, compiled by the International Institute for Applied Systems Analysis, indicates that, globally, domestic energy consumption accounts for about a quarter of global greenhouse gas emissions. A fundamental shift in energy consumption is needed, moving away from the use of fossil fuels to meet emission reduction targets.
Auteurs: Wokje Abrahamse;Sarah Darby;Katherine McComas;
Apparue dans: IEEE Power and Energy Magazine
Date publication: 02.-2018, volume: 16, issue:1, pages: 29 - 34
Editeur: IEEE
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» Communication Modeling for Differential Protection in IEC-61850-Based Substations
Résumé:
Today's power utilities, around the world, own multiple substations that are connected together to form a complex energy network. The functions within and between these substations are being automated according to globally accepted power utility automation standard IEC 61850. This automation results in efficient operation and enhanced protection of power network with the aid of the communication system. Implementing the protection schemes modeled using communication configurations of standardized information exchange will lead to digital power grid. Designing an IEC-61850-based protection scheme to take care of the faults outside the substations is a challenge, as the typical local-area-network-based generic-object-oriented substation events and sampled-value messages need to be transmitted over a wide-area network. This paper presents communication configuration for line current differential protection schemes applied between two automated substations. It presents the simulation results of communication configuration network between two substations. Its performance is evaluated using a network simulator tool. This study intends to guide the development of a robust protection scheme with IEC-61850-based communication configuration.
Auteurs: Ikbal Ali;S. M. Suhail Hussain;Ashok Tak;Taha Selim Ustun;
Apparue dans: IEEE Transactions on Industry Applications
Date publication: 02.-2018, volume: 54, issue:1, pages: 135 - 142
Editeur: IEEE
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» Compact Analytical Model to Extract Write Static Noise Margin (WSNM) for SRAM Cell at 45-nm and 65-nm Nodes
Résumé:
The operation of static random access memory (SRAM) in the subthreshold region reduces both leakage power and access energy. Subthreshold operation is one of the proficient techniques to accomplish low-power and high performance system on chip. But the challenge, in subthreshold SRAM design, is the SRAM stability. The sensitivity to process variations increases with technology scaling resulting in reduced stability. In this paper, SRAM write stability is analyzed in the subthreshold region. The semi-analytical model of write static noise margin (WSNM) for 6T SRAM (subthreshold region) has been given in this paper. The results obtained from the analytical model are verified through simulations in Cadence using GPDK 45-nm, UMC 65-nm, and UMC 130-nm technology files. The model is based on the subthreshold current equations of the transistor. Further, the write stability of the SRAM is analyzed with the varying supply voltage and the sizing ratios. The process corner analyses is also accomplished to verify the write stability of the SRAM cell using the model at the worst process corners. To the best of the author’s knowledge, this is the first model to analyze the WSNM based on the traditional butterfly static noise margin approach. It has been observed that the model is valid for all of the technology nodes, i.e., at 45 nm, 65 nm, as well as 130 nm. Also the model holds well for 8T and 10T SRAM configurations in addition to 6T SRAM cell.
Auteurs: Ruchi;Sudeb Dasgupta;
Apparue dans: IEEE Transactions on Semiconductor Manufacturing
Date publication: 02.-2018, volume: 31, issue:1, pages: 136 - 143
Editeur: IEEE
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» Compact and Wideband Millimeter-Wave Antenna-Coupled Detector
Résumé:
This paper presents a compact and wideband millimeter-wave antenna-coupled detector, with a Schottky diode directly integrated across the feeding terminals of a planar dipole. An integrated wideband dipole is proposed, as a radiator as well as a radio frequency choke. It contains a pair of folded strips for broadening the bandwidth and a pair of U-slot resonators for sidelobe reduction, both of which facilitate the compact design. To form unidirectional radiation with a low profile, a hybrid reactive impedance surface is presented, which can simultaneously enhance the gain and impedance bandwidths covering the full Ka-band. An equivalent circuit model is provided to illustrate the operating mechanism of this antenna-coupled detector, and the mounting effect caused by the diode is examined. A Ka-band prototype with dimensions of about $1.12lambda _{0}times 1.12lambda _{0}times 0.08lambda _{0}$ is fabricated and characterized, exhibiting a responsivity between 1500 and 3800 V/W over the full Ka-band. The proposed design has the advantages of broad bandwidth, low profile, small footprint, and mechanically stable structure. It can be fabricated using low-cost printed circuit technology, and can easily be configured into a planar 2-D array, making it suitable for low-cost sensing and imaging applications based on small unmanned aerial vehicles.
Auteurs: Jinchao Mou;Zhongxiang Shen;Dalu Guo;Xin Lv;
Apparue dans: IEEE Transactions on Microwave Theory and Techniques
Date publication: 02.-2018, volume: 66, issue:2, pages: 1058 - 1069
Editeur: IEEE
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» Compact and Wideband MMIC Phase Shifters Using Tunable Active Inductor-Loaded All-Pass Networks
Résumé:
To address the challenging needs of small size, wide bandwidth, and low-frequency applicability, a novel phase shifter implementation is introduced that utilizes tunable active differential inductors within all-pass networks. The inductor tuning is used to achieve phase shifts up to 180°. A switchable active balanced-to-unbalanced transition (balun) circuit is included in front of the all-pass network to complement its phase shift capability by another 180°. In addition, the all-pass network is followed by a variable-gain amplifier to correct for gain variations among the phase shifting states and act as an output buffer. Although active inductors have previously been used in the design of various components, to the best of our knowledge this is the first time that they have been used in an all-pass phase shifter. The approach is demonstrated with an on-chip design and implementation exhibiting wideband performance for S- and L-band applications by utilizing the 0.5- $mu text{m}$ TriQuint pHEMT GaAs monolithic microwave integrated circuits (MMIC) process. Specifically, the presented phase shifter $1 times 3.95~ text {mm}^{2}$ die area and operates within the 1.5–3-GHz band (i.e., 2:1 bandwidth) with 10-dB gain, less than 1.5-dB root-mean-square (rms) gain error and less than 9° rms phase error. Comparison with the state-of-the-art MMIC phase shifters operating in S- and L-bands demonstrates that the presented phase shifter exhibits a remarkable bandwidth performance from a very compact footprint with low-power consumption. Consequently, it presents an alternative for the implementation of wideband phase shifters where all-passive implementations will consume expensive die real estate.
Auteurs: David M. Zaiden;John E. Grandfield;Thomas M. Weller;Gokhan Mumcu;
Apparue dans: IEEE Transactions on Microwave Theory and Techniques
Date publication: 02.-2018, volume: 66, issue:2, pages: 1047 - 1057
Editeur: IEEE
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» Compact Deep UV System at 222.5 nm Based on Frequency Doubling of GaN Laser Diode Emission
Résumé:
Laser light sources emitting in the deep ultraviolet wavelength range between 210 and 230 nm are of great interest for spectroscopic applications. Here, a compact DUV diode laser system emitting at a wavelength of 222.5 nm is presented. The system is based on frequency doubling of the laser radiation from a micro-integrated GaN external cavity diode laser module ( $mu $ ECDL) emitting at 445 nm. The $mu $ ECDL has an optical pump power of 1.4 W with an emission bandwidth of 35 pm. Narrowband laser radiation in continouos wave operation with an output power of $160~mu text{W}$ at 222.5 nm is generated in a single-pass frequency doubling stage with a $beta $ -BaB2O4 crystal. The results are suitable to address applications such as spectroscopic investigations of biological samples. The presented concept of a compact and efficient deep ultraviolet laser light source enables the realization of portable systems for which a small footprint and a low power consumption is essential.
Auteurs: Norman Ruhnke;André Müller;Bernd Eppich;Martin Maiwald;Bernd Sumpf;Götz Erbert;Günther Tränkle;
Apparue dans: IEEE Photonics Technology Letters
Date publication: 02.-2018, volume: 30, issue:3, pages: 289 - 292
Editeur: IEEE
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» Compact Spintronic Muller C-Element With Near-Zero Standby Energy
Résumé:
The complementary roles of asynchronous architecture with nonvolatile spintronic devices are explored herein to realize a novel asynchronous logic element. By redesigning the Muller C-element to take advantage of spintronic device non-volatility and area efficiency, benefits such as reduced asynchronous handshaking area overhead, are achieved in addition to instant on/off capabilities for reduced static-power dissipation through power gating. We propose a novel eight transistor and one spintronic device Muller C-element design which is 20% faster and uses 68% of the power of previous non-volatile Muller C-element designs. This spintronic Muller C-element is demonstrated within a four-phase dual-rail asynchronous pipeline resulting in 48% fewer transistors in comparison with the previous designs. Additionally, bundled-data protocol overhead is shown to be reduced by using the spintronic Muller C-element proposed herein. Detailed analysis of the effects of driving transistor width and the tunneling magnetoresistance ratio on device performance characteristics is included.
Auteurs: Steven D. Pyle;Deliang Fan;Ronald F. Demara;
Apparue dans: IEEE Transactions on Magnetics
Date publication: 02.-2018, volume: 54, issue:2, pages: 1 - 7
Editeur: IEEE
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» Compact Unilateral Circularly Polarized Dielectric Resonator Antenna
Résumé:
A compact circularly polarized (CP) unidirectional dielectric resonator (DR) antenna (DRA) with lateral radiation is investigated for the first time. It requires two sets of CP far fields that have complementary patterns. The first set is obtained using the DR $text {TM}_{mathrm {01delta }}$ and ${text {TE}}_{mathrm {01delta +1}}$ mode. For the second set, the CP DR-loaded slot antenna is used, which is realized by a cutting cross-slot in the ground plane. To demonstrate the idea, a CP unidirectional DRA is designed at 2.4 GHz for wireless local area network applications. A prototype was fabricated and tested, and reasonable agreement between the measured and simulation results is obtained. It was measured that its overlapping impedance and axial ratio bandwidth is 4.9% (2.39–2.51 GHz), with a front-to-back ratio of 15.5 dB at 2.44 GHz.
Auteurs: Lei Guo;Kwok Wa Leung;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 02.-2018, volume: 66, issue:2, pages: 668 - 674
Editeur: IEEE
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» Compact Wideband Balanced Bandpass Filters With Very Broad Common-Mode and Differential-Mode Stopbands
Résumé:
Compact balanced bandpass filters based on a combination of multisection mirrored stepped-impedance resonators and interdigital capacitors are presented in this paper. The considered filter topology is useful to achieve wide bandwidths for the differential mode, with broad stop bands for that mode, as well as very efficient common-mode suppression. By conveniently adjusting the transmission zeros for both operation modes, the differential- and common-mode stopbands can be extended up to significantly high frequencies. Filter size and this differential- and common-mode stopband performance are the main relevant characteristics of the proposed balanced filters. The potential of the approach is illustrated by the design of a prototype order-5 balanced bandpass filter, with central frequency $f_{0} = 1.8$ GHz, 48% fractional bandwidth (corresponding to 55.4% −3-dB bandwidth), and 0.04-dB ripple level. The filter is automatically synthesized by means of an aggressive space-mapping software tool, specifically developed, and two (pre- and post-) optimization algorithms, necessary to determine the transmission-zero frequencies. The designed filter is as small as $0.48lambda _{g} times 0.51lambda _{g}$ , where $lambda _{g}$ is the guided wavelength at the central filter frequency, and the differential-mode stopband extends up to at least 6.5 GHz with more than 22-dB rejection. The common-mode suppression is better than 28 dB from dc up to at least 6.5 GHz.
Auteurs: Marc Sans;Jordi Selga;Paris Vélez;Jordi Bonache;Ana Rodríguez;Vicente E. Boria;Ferran Martín;
Apparue dans: IEEE Transactions on Microwave Theory and Techniques
Date publication: 02.-2018, volume: 66, issue:2, pages: 737 - 750
Editeur: IEEE
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» Comparison Between a Thin Lens Antenna Made of Structured Dielectric Material and Conventional Lens Antennas, in Q-Band in a Compact Volume
Résumé:
In this letter, the performance of a diffractive gradient index lens antenna, constructed by using dielectric subwavelength structuration and manufactured by three-dimensional printing, is compared to the ones of conventional lens antennas in a small footprint configuration. It discusses the advantages and drawbacks of each configuration and compares the simulated and measured gain performances. It shows that structured lens antenna can achieve gain superior to conventional approaches, combined with a 1 dB bandwidth of 10.9%, thanks to the engineering of artificial gradient index. All these benefits are coming with a significant decrease in the antenna weight for the same footprint.
Auteurs: Alpha O. Diallo;Romain Czarny;Brigitte Loiseaux;Stéphane Holé;
Apparue dans: IEEE Antennas and Wireless Propagation Letters
Date publication: 02.-2018, volume: 17, issue:2, pages: 307 - 310
Editeur: IEEE
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» Comparison Between High-Holding-Voltage SCR and Stacked Low-Voltage Devices for ESD Protection in High-Voltage Applications
Résumé:
The modified silicon-controlled rectifier (SCR) fabricated in a 0.25- $mu text{m}$ high-voltage (HV) bipolar-CMOS-DMOS (BCD) technology has been proposed to seek for both effective electrostatic discharge (ESD) protection and latchup immunity. Experimental results show that one of the proposed SCRs has a high holding voltage of up to ~30 V in the 100-ns transmission line pulsing measurement results. However, through the experimental verification by using the transient latchup test, the holding voltage of such proposed device decreases to ~20 V. It is due to the increased bipolar junction transistor current gains of the SCR path induced by the Joule-heating effect in the long-term measurement. For 20-V circuit applications, the ESD robustness of the proposed SCR with a holding voltage of ~20 V is lower than that of stacked low-voltage p-type MOS in the previous studies. Developing special modification of such HV devices is inefficient to achieve both effective ESD protection and latchup-free design in this 0.25- $mu text{m}$ HV BCD technology.
Auteurs: Chia-Tsen Dai;Ming-Dou Ker;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 02.-2018, volume: 65, issue:2, pages: 798 - 802
Editeur: IEEE
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» Comparison With Nitride Interface Defects and Nanocrystals for Charge Trapping Layer Nanowire Gate-All-Around Nonvolatile Memory Performance
Résumé:
This paper demonstrates novel silicon–oxide–nitride–nitride–oxide–silicon (SONNOS) and silicon-oxide-nanocrystals-oxide-silicon (SOncOS) nonvolatile memory (NVM) that is based on nanowires gate-all-around (GAA) structure. SONNOS and SOncOS NVM exploit doubly stacked Si3N4 (NN) interface defects and silicon nanocrystals as charge trapping layers, respectively. Experimental results reveal that SONNOS NVM has superior memory characteristics than SOncOS NVM. With respect to memory reliability, the SONNOS NVM retains 86% memory window after 104 program/erase cycles, and the memory window retains 42% of the originally stored charge after ten years. Such doubly stacked Si3N4 layers provide additionally charge trapping sites in CTL, improving the memory performance of NVM. In the future, SONNOS GAA NVMs will be easily integrated in 3-D nand flash memory applications.
Auteurs: Yu-Ru Lin;Yi-Wei Chiang;Yu-Hsien Lin;Wei-Cheng Wang;Yung-Chun Wu;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 02.-2018, volume: 65, issue:2, pages: 493 - 498
Editeur: IEEE
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» Compensator-Free Mixed-Ripple Adaptive On-Time Controlled Boost Converter
Résumé:
A mixed-ripple adaptive on-time controlled boost converter is proposed. With the proposed control method, the compensator network is no longer required. Hence, the chip area and cost can be reduced, and a satisfied load regulation still can be achieved. Besides, a novel on-time generator is proposed to fix the switching frequency in continuous conduction mode (CCM). Moreover, a differential difference comparator is proposed to simplify the circuits and further reduce chip area. Furthermore, with the proposed control, the converter is capable of smoothly switching between discontinuous conduction mode and CCM, depending on the loading condition. The proposed boost converter was implemented by using a 0.18- $mu text{m}$ 1P6M mixed-signal process, and the chip area is 0.88 mm2. The input voltage may range from 0.8 to 1.4 V, the output voltage is set to 1.8 V, and the measured peak efficiency is 92.4%.
Auteurs: Chi-Hsiang Huang;Hung-Hsien Wu;Chia-Ling Wei;
Apparue dans: IEEE Journal of Solid-State Circuits
Date publication: 02.-2018, volume: 53, issue:2, pages: 596 - 604
Editeur: IEEE
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» Competitive Interplay of Production Decisions: Rivalry Between Established and Startup Firms
Résumé:
This paper's novelty is the modeling of competition in production quantity and product-launch timing, which has been silent regarding the impact of these interdependent decisions on firm survival. We rigorously address the competitive interplay between a startup and an established rival by developing a game-theoretic model that captures the startup's vulnerability to failure through maximizing its survival likelihood. We allow the established rival to behave strategically by anticipating the startup's timing and production decisions prior to making its own production decision. We propose that unless the market-entry investment is low, a survival-maximizing startup should wait to launch its product, and do so with a larger production output than the established rival, when delaying the product launch enables the startup to charge a high price. Insights on the established firm involve the benefit from behaving strategically, which is when competing with either a survival-maximizing or profit-maximizing startup. If the market-entry investment is large, comparing a survival-maximizing startup with a profit-maximizing startup suggests that the former produces at a larger scale than the latter when either startup competes with an established rival, which in turn is forced to reduce its production level.
Auteurs: Moren Lévesque;Xuan (Jen) Zhao;Junsong Bian;
Apparue dans: IEEE Transactions on Engineering Management
Date publication: 02.-2018, volume: 65, issue:1, pages: 85 - 98
Editeur: IEEE
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» Competitive Linearity for Envelope Tracking: Dual-Band Crest Factor Reduction and 2D-Vector-Switched Digital Predistortion
Résumé:
As wireless communication standards evolve to support ever-higher data rates, the required linearity and bandwidth must increase, which leads to higher energy consumption [1]. The problem of high energy consumption has become more serious due to the wide-spread adoption of orthogonal frequency-division multiplexing (OFDM), which is used in long-term evolution (LTE) and Wi-Fi applications [2]. The low energy efficiency of OFDM-based systems results from the statistical distribution of OFDM signals, combined with the efficiency characteristics of power amplifiers (PAs).
Auteurs: Harald Enzinger;Karl Freiberger;Christian Vogel;
Apparue dans: IEEE Microwave Magazine
Date publication: 02.-2018, volume: 19, issue:1, pages: 69 - 77
Editeur: IEEE
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» Complementary Aspect-Based Opinion Mining
Résumé:
Aspect-based opinion mining is finding elaborate opinions towards a subject such as a product or an event. With explosive growth of opinionated texts on the Web, mining aspect-level opinions has become a promising means for online public opinion analysis. In particular, the boom of various types of online media provides diverse yet complementary information, bringing unprecedented opportunities for cross media aspect-opinion mining. Along this line, we propose CAMEL, a novel topic model for complementary aspect-based opinion mining across asymmetric collections. CAMEL gains information complementarity by modeling both common and specific aspects across collections, while keeping all the corresponding opinions for contrastive study. An auto-labeling scheme called AME is also proposed to help discriminate between aspect and opinion words without elaborative human labeling, which is further enhanced by adding word embedding-based similarity as a new feature. Moreover, CAMEL-DP, a nonparametric alternative to CAMEL is also proposed based on coupled Dirichlet Processes. Extensive experiments on real-world multi-collection reviews data demonstrate the superiority of our methods to competitive baselines. This is particularly true when the information shared by different collections becomes seriously fragmented. Finally, a case study on the public event “2014 Shanghai Stampede” demonstrates the practical value of CAMEL for real-world applications.
Auteurs: Yuan Zuo;Junjie Wu;Hui Zhang;Deqing Wang;Ke Xu;
Apparue dans: IEEE Transactions on Knowledge and Data Engineering
Date publication: 02.-2018, volume: 30, issue:2, pages: 249 - 262
Editeur: IEEE
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» Complementary Coded Scrambling Multiple Access and Its Performance in Downlink MIMO Channels
Résumé:
In a traditional complementary coded CDMA (CC-CDMA) system, signals are spread using the direct sequence (DS) technique to suppress multipath interference (MI) and multiple access interference (MAI). However, DS spreading suffers from very poor bandwidth efficiency. This paper proposes a scrambling-based CC-CDMA system, namely complementary coded scrambling multiple access (CCSMA). A CCSMA system offers a unified platform to integrate CC-CDMA, multiple-input multiple-output (MIMO), and scrambling technique seamlessly. Utilizing complementary codes in scrambling modulation, a CCSMA system is able to suppress MI and MAI effectively. With the help of space domain scrambling, the CCSMA system offers much higher bandwidth efficiency than a CC DS-CDMA system. Bit error rate and system capacity are evaluated explicitly in this paper, verifying that CCSMA is a viable multiple access technique for providing high capacity in downlink MIMO channels.
Auteurs: Xiqing Liu;Hong-Ming Syu;Hsiao-Hwa Chen;Weixiao Meng;Meng Wei;
Apparue dans: IEEE Transactions on Wireless Communications
Date publication: 02.-2018, volume: 17, issue:2, pages: 835 - 847
Editeur: IEEE
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» Complementary Integrated Circuits Based on p-Type SnO and n-Type IGZO Thin-Film Transistors
Résumé:
Oxide semiconductors are highly attractive for the new-generation transparent/flexible electronics. In this letter, logic gates (inverter, NAND, and transmission gates) and three-stage ring oscillators based on n-type indium-gallium-zinc-oxide (IGZO) thin-film transistors (TFTs) and p-type tin monoxide (SnO) TFTs are presented. The IGZO TFTs show a mobility of 10.05 cm $^{textsf {2}}$ /( $textsf {V}cdot textsf {s}$ ) and a threshold voltage of 5.00 V. The SnO TFTs exhibit a mobility of 1.19 cm $^{textsf {2}}$ /( $textsf {V}cdot textsf {s}$ ) and a matched threshold voltage of −5.05 V. At a supply voltage of 10 V, the complementary inverters show an extremely high gain of 112 with a geometric aspect ratio of 5. The dynamic responses of the logic gates based on n-type IGZO and p-type SnO TFTs are also examined. The delay time of the inverter measured from dynamic response is 27.75 $mu text{s}$ at a supply voltage of 10 V. The inverter, NAND, and transmission gates all exhibit ideal rail-to-rail output voltage behavior. At a supply voltage of 20 V, the three-stage ring oscillators are able to operate at 32.87 kHz, and the stage delay is $5.07~mu text{s}$ .
Auteurs: Yunpeng Li;Jin Yang;Yiming Wang;Pengfei Ma;Yvzhuo Yuan;Jiawei Zhang;Zhaojun Lin;Li Zhou;Qian Xin;Aimin Song;
Apparue dans: IEEE Electron Device Letters
Date publication: 02.-2018, volume: 39, issue:2, pages: 208 - 211
Editeur: IEEE
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» Complete Targets Coverage in Wireless Sensor Networks With Energy Transfer
Résumé:
This letter considers energy harvesting sensor nodes monitoring multiple fixed targets. The goal is to monitor these targets for the longest time period. A key challenge, however, is that sensor nodes have varying energy harvesting rates, meaning that the coverage lifetime of targets is limited by sensor nodes with low energy. To this end, we consider energy sharing between sensor nodes. We model the problem as a mixed integer linear program (MILP). Advantageously, our MILP models non-linear energy conversion rates. We also outline a heuristic for large-scale networks. Our results show energy sharing and non-linear energy conversion rates prolong coverage lifetime. Finally, our heuristic achieves 90% of the optimal coverage lifetime.
Auteurs: Changlin Yang;Kwan-Wu Chin;Ying Liu;Junbao Zhang;Jizhao Liu;
Apparue dans: IEEE Communications Letters
Date publication: 02.-2018, volume: 22, issue:2, pages: 396 - 399
Editeur: IEEE
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» Complexity and Algorithms for Finding a Perfect Phylogeny from Mixed Tumor Samples
Résumé:
Hajirasouliha and Raphael (WABI 2014) proposed a model for deconvoluting mixed tumor samples measured from a collection of high-throughput sequencing reads. This is related to understanding tumor evolution and critical cancer mutations. In short, their formulation asks to split each row of a binary matrix so that the resulting matrix corresponds to a perfect phylogeny and has the minimum number of rows among all matrices with this property. In this paper, we disprove several claims about this problem, including an NP-hardness proof of it. However, we show that the problem is indeed NP-hard, by providing a different proof. We also prove NP-completeness of a variant of this problem proposed in the same paper. On the positive side, we propose an efficient (though not necessarily optimal) heuristic algorithm based on coloring co-comparability graphs, and a polynomial time algorithm for solving the problem optimally on matrix instances in which no column is contained in both columns of a pair of conflicting columns. Implementations of these algorithms are freely available at https://github.com/alexandrutomescu/MixedPerfectPhylogeny.
Auteurs: Ademir Hujdurović;Urša Kačar;Martin Milanič;Bernard Ries;Alexandru I. Tomescu;
Apparue dans: IEEE/ACM Transactions on Computational Biology and Bioinformatics
Date publication: 02.-2018, volume: 15, issue:1, pages: 96 - 108
Editeur: IEEE
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» Complexity of Energy Efficient Localization With the Aid of a Mobile Beacon
Résumé:
Localization is an essential service in wireless sensor networks. Trilateration is a commonly used solution to range-based localization for providing such services. It might be, however, impossible to localize the entire network at once using trilateration due to low connectivity on sparse deployments. In such scenarios, a mobile beacon with a known position is used to move among and locate the nodes with low connectivity to aid trilateration. Given a network graph, finding a minimum energy route traveled by the mobile beacon is a key problem in many real-world applications. We prove in this letter that this problem called mobile assisted trilateration based energy optimum localization is NP-hard. To the best of our knowledge, this is the first such result in an attempt to computationally classify this important problem. We also provide a compact integer linear programming formulation for the problem.
Auteurs: Hüseyin Akcan;Cem Evrendilek;
Apparue dans: IEEE Communications Letters
Date publication: 02.-2018, volume: 22, issue:2, pages: 392 - 395
Editeur: IEEE
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» Complexity of Verifying Nonblockingness in Modular Supervisory Control
Résumé:
Complexity analysis becomes a common task in supervisory control. However, many results of interest are spread across different topics. The aim of this paper is to bring several interesting results from complexity theory and to illustrate their relevance to supervisory control by proving new nontrivial results concerning nonblockingness in modular supervisory control of discrete event systems modeled by finite automata.
Auteurs: Tomáš Masopust;
Apparue dans: IEEE Transactions on Automatic Control
Date publication: 02.-2018, volume: 63, issue:2, pages: 602 - 607
Editeur: IEEE
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» Comprehensive electrical and thermal analysis of the stress grading system of a large hydro generator
Résumé:
In the slot portion of a generator core the installed stator bars are covered with a semi-conductive coating to prevent partial discharge (PD) activity between the main insulation surface and the grounded laminated sheets. Typically, this outer corona protection (OCP) layer ends a few centimeters outside the slot portion. To suppress PD-activity at the end of the OCP, a field grading is mandatory for machines with a rated voltage greater than approximately 6 kV. Figure 1 shows the effect of a stress grading layer on stator bars energized to high voltage. It suppresses potential creepage discharges at the OCP ends caused by field enhancement.
Auteurs: Christian Staubach;Thomas Hildinger;Axel Staubach;
Apparue dans: IEEE Electrical Insulation Magazine
Date publication: 02.-2018, volume: 34, issue:1, pages: 37 - 49
Editeur: IEEE
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» Comprehensive Fault Type Discrimination Concept for Bipolar Full-Bridge-Based MMC HVDC Systems with Dedicated Metallic Return
Résumé:
Bipolar HVDC transmission systems typically offer up to 50% transmission redundancy in case of single pole-to-ground line faults. Continuous operation during permanent multiconductor faults, however, is not permitted, emphasizing the need for accurate fault type discrimination in such applications. For bipolar schemes with a dedicated metallic return (DMR) conductor, discrimination of pole–ground faults and pole–DMR faults represents a challenging task due to their similar electrical characteristics. In this paper, several approaches to detect DMR fault involvement are identified and analyzed, comprising both noninvasive methods based on measurement data and invasive methods based on DC current control strategies of full-bridge VSC-MMC stations (Modular Multilevel Converter based on Voltage Source Converter technology). An exemplified point-to-point HVDC system is modeled in PSCAD/EMTDC and extensive simulation studies are carried out. Based on the obtained results, a comprehensive fault type discrimination concept for permanent line faults is developed, which can be incorporated into fault handling schemes. Thus, successful fault type discrimination can be performed for all relevant fault types, even under exceptional fault conditions.
Auteurs: Philipp Tünnerhoff;Philipp Ruffing;Armin Schnettler;
Apparue dans: IEEE Transactions on Power Delivery
Date publication: 02.-2018, volume: 33, issue:1, pages: 330 - 339
Editeur: IEEE
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» Compressed-Sensing Assisted Spatial Multiplexing Aided Spatial Modulation
Résumé:
Spatial-multiplexing aided spatial modulation (SMx-SM) is proposed, which intrinsically amalgamates the concept of vertical bell labs space-time (V-BLAST) and SM to attain a high transmission rate, despite its low number of radio frequency (RF) chains at the transmitter. Specifically, in the SMx-SM scheme, the transmit antennas are partitioned into groups and the SM technique is applied individually to each group. Furthermore, low-complexity threshold-aided compressive sensing-based and message passing-based detectors are derived for our SMx-SM system. Our simulation results show that the proposed SMx-SM system exhibits a better performance despite its lower complexity than the conventional generalized spatial modulation system. More importantly, the proposed SMx-SM system is capable of providing considerable performance gains over the V-BLAST system at the same number of RF chains and throughput. Finally, an upper bound is derived for the average bit error probability, which is confirmed by our simulation results.
Auteurs: Lixia Xiao;Yue Xiao;Chao Xu;Xia Lei;Ping Yang;Shaoqian Li;Lajos Hanzo;
Apparue dans: IEEE Transactions on Wireless Communications
Date publication: 02.-2018, volume: 17, issue:2, pages: 794 - 807
Editeur: IEEE
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» Compressive Representation for Device-Free Activity Recognition with Passive RFID Signal Strength
Résumé:
Understanding and recognizing human activities is a fundamental research topic for a wide range of important applications such as fall detection and remote health monitoring and intervention. Despite active research in human activity recognition over the past years, existing approaches based on computer vision or wearable sensor technologies present several significant issues such as privacy (e.g., using video camera to monitor the elderly at home) and practicality (e.g., not possible for an older person with dementia to remember wearing devices). In this paper, we present a low-cost, unobtrusive, and robust system that supports independent living of older people. The system interprets what a person is doing by deciphering signal fluctuations using radio-frequency identification (RFID) technology and machine learning algorithms. To deal with noisy, streaming, and unstable RFID signals, we develop a compressive sensing, dictionary-based approach that can learn a set of compact and informative dictionaries of activities using an unsupervised subspace decomposition. In particular, we devise a number of approaches to explore the properties of sparse coefficients of the learned dictionaries for fully utilizing the embodied discriminative information on the activity recognition task. Our approach achieves efficient and robust activity recognition via a more compact and robust representation of activities. Extensive experiments conducted in a real-life residential environment demonstrate that our proposed system offers a good overall performance and shows the promising practical potential to underpin the applications for the independent living of the elderly.
Auteurs: Lina Yao;Quan Z. Sheng;Xue Li;Tao Gu;Mingkui Tan;Xianzhi Wang;Sen Wang;Wenjie Ruan;
Apparue dans: IEEE Transactions on Mobile Computing
Date publication: 02.-2018, volume: 17, issue:2, pages: 293 - 306
Editeur: IEEE
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» Computational Intelligence Techniques for Mobile Network Optimization [Guest Editorial]
Résumé:
Modern society has become increasingly reliant on mobile networks for their communication needs. Such networks are characterized by their dynamic, heterogeneous, complex, and data intensive nature, which makes them more amenable to automated mobile network optimization performed using “computational intelligence’’ (CI) techniques rather than traditional optimization approaches. CI techniques—which subsume multidisciplinary techniques from machine learning (ML), optimization theory, game theory, control theory, and meta-heuristics— have a rich history in terms of being deployed in networking. CI techniques are highly suited to the mobile networking architectures and the dynamic environments they characterize. Looking ahead, it looks likely that CI will play a leading role in upcoming 5th generation (5G) wireless mobile networks for developing optimized solutions for vexing problems—such as traffic scheduling and routing, capacity, coverage, and power optimization—in the face of stringent requirements and highly dynamic conditions. The importance of our proposed theme of mobile network optimization (MNO) motivated us to propose this special issue in the IEEE Computational Intelligence Magazine (CIM)—the premier IEEE magazine for professionals interested in CI techniques and their applications.
Auteurs: Junaid Qadir;Amir Hussain;Kok-Lim Alvin Yau;Muhammad Ali Imran;Adam Wolisz;
Apparue dans: IEEE Computational Intelligence Magazine
Date publication: 02.-2018, volume: 13, issue:1, pages: 28 - 28
Editeur: IEEE
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» Computationally Efficient Pitch and Roll Estimation Using a Unit Direction Vector
Résumé:
This paper introduces a new attitude estimation algorithm for pitch and roll angles. Pitch and roll angles are represented by a unit vector, and its estimation error is estimated in the Kalman filter. The main theoretical contribution is that the error covariance equations are simplified to scalar equations. Thus, the proposed algorithm is computationally efficient. The proposed algorithm is also applied to vertical movement estimation. Simulation and experiment results show the effectiveness of the proposed method.
Auteurs: Young Soo Suh;
Apparue dans: IEEE Transactions on Instrumentation and Measurement
Date publication: 02.-2018, volume: 67, issue:2, pages: 459 - 465
Editeur: IEEE
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» Computationally Efficient TDOA/FDOA Estimation for Unknown Communication Signals in Electronic Warfare Systems
Résumé:
The cross ambiguity function (CAF) has been commonly used to find time difference of arrival (TDOA) and frequency difference of arrival (FDOA). In most cases, direct computation of the CAF by using a conventional method such as fast Fourier transform is too computationally intensive. Thus, a two-stage approach consisting of a coarse mode to find rough TDOA/FDOA estimates and a fine mode for precise estimation was introduced. However, there has been no methodology for selecting an interpolation factor determined by the sampling frequency and target precision which significantly affects the computational complexity. In addition, even if the computational complexity can be reduced by using the optimal interpolation factor, the huge transmission data through the datalink between sensors and the central station still remains to be an obstacle for an electronic warfare (EW) system. In this respect, we derive an optimal interpolation factor and then propose a new two-stage TDOA/FDOA estimation algorithm using a resampling block to reduce the computational complexity and the data size simultaneously in EW systems. In the proposed method, the optimal interpolation factor can be used irrespective of the sampling frequency and the target precision. Simulation results show that the optimal interpolation factor efficiently reduces the computational burden without the loss of estimation performance.
Auteurs: Dong-Gyu Kim;Geun-Ho Park;Hyoung-Nam Kim;Jin-Oh Park;Young-Mi Park;Wook-Hyeon Shin;
Apparue dans: IEEE Transactions on Aerospace and Electronic Systems
Date publication: 02.-2018, volume: 54, issue:1, pages: 77 - 89
Editeur: IEEE
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» Computing by slide rule
Résumé:
When does your computer need a slide rule? When it is the UNIVAC II. This 1950s circular slide rule from Remington Rand was used by programmers to optimize how the mainframe executed instructions. The computer had a drum memory that was constantly rotating, and the most efficient program would position the drum so that the next instruction would begin executing wherever the current instruction finished. Instructions were thus scattered across the drum and not physically adjacent to one another. To minimize rotational delays, a programmer had to figure out each instruction’s execution time in order to queue up the next command, an approach called minimum latency programming. Though the slide rule wasn’t strictly necessary to make those calculations, it probably helped
Auteurs: Allison Marsh;
Apparue dans: IEEE Spectrum
Date publication: 02.-2018, volume: 55, issue:2, pages: 56 - 56
Editeur: IEEE
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» Concept of a Magnetically Enhanced Vacuum Arc Thruster With Controlled Distribution of Ion Flux
Résumé:
In this paper, we present a concept of a magnetically enhanced vacuum arc thruster with an additional coil to control and shape the spatial distribution of the outlet ion flux. We introduce several operation modes by considering the operation of the original thruster and drawing an analogy with the technological setups equipped with vacuum arc plasma sources. To discuss the effect of the additional magnetic field, a plasma optic model is applied. Important regularity is deduced from the comparative analysis of the microthruster and macrosetup plasmas: quasi-neutrality of the plasmas is the same (about $10^{-6}$ ), and the magnetic control is applied effectively when the plasma density n ( $text{m}^{-3}$ ) and a spatial extent a (m) of the domain occupied by the plasma are connected by the dependence na3 $=10^{-14}$ .
Auteurs: Oleg O. Baranov;Uroš Cvelbar;Kateryna Bazaka;
Apparue dans: IEEE Transactions on Plasma Science
Date publication: 02.-2018, volume: 46, issue:2, pages: 304 - 310
Editeur: IEEE
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» Conference Calendar [Conference Calendar]
Résumé:
Presents the CIS committee calendar of upcoming events and meetings.
Auteurs: Bernadette Bouchon-Meunier;
Apparue dans: IEEE Computational Intelligence Magazine
Date publication: 02.-2018, volume: 13, issue:1, pages: 62 - 62
Editeur: IEEE
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» Conference Report on 2017 IEEE International Conference on Computational Intelligence in Bioinformatics and Computational Biology (IEEE CIBCB 2017) [Conference Reports]
Résumé:
Presents information on the 2017 IEEE International Conference on Computational Intelligence .
Auteurs: Richard Allmendinger;
Apparue dans: IEEE Computational Intelligence Magazine
Date publication: 02.-2018, volume: 13, issue:1, pages: 23 - 24
Editeur: IEEE
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» Confluence: Speeding Up Iterative Distributed Operations by Key-Dependency-Aware Partitioning
Résumé:
A typical shuffle operation randomly partitions data on many computers, generating possibly a significant amount of network traffic which often dominates a job's completion time. This traffic is particularly pronounced in iterative distributed operations where each iteration invokes a shuffle operation. We observe that data of different iterations are related according to the transformation logic of distributed operations. If data generated by the current iteration are partitioned to the computers where they will be processed in the next iteration, unnecessary shuffle network traffic between the two iterations can be prevented. We model general iterative distributed operations as the transform-and-shuffle primitive and define a powerful notion named Confluence key dependency to precisely capture the data relations in the primitive. We further find that by binding key partitions between different iterations based on the Confluence key dependency, the shuffle network traffic can always be reduced by a predictable percentage. We implemented the Confluence system. Confluence provides a simple interface for programmers to express the Confluence key dependency, based on which Confluence automatically generates efficient key partitioning schemes. Evaluation results on diverse real-life applications show that Confluence greatly reduces the shuffle network traffic, resulting in as much as 23 percent job completion time reduction.
Auteurs: Feng Liang;Francis C. M. Lau;Heming Cui;Cho-Li Wang;
Apparue dans: IEEE Transactions on Parallel and Distributed Systems
Date publication: 02.-2018, volume: 29, issue:2, pages: 351 - 364
Editeur: IEEE
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» Conformal Beam-Steering Antenna Controlled by a Raspberry Pi for Sustained High-Throughput Applications
Résumé:
A complete autonomous system consisting of a beam-steerable hemispherical square-loop antenna (HSLA) controlled by a Raspberry Pi is presented for optimizing the throughput in a scattered and a poor signal-to-noise ratio environment. Four different indoor communication configurations at various distances were analyzed in the presence of interferences. In three configurations, HSLA performance was also compared to that of a standard monopole antenna link. It was found that HSLA can offer up to 1450% higher throughput and can withstand much higher interference levels before the system breaks. In terms of quality, this means sustaining compressed high-definition communications. In effect, it improves the system throughput for the test 2.4 GHz (802.11b/g/n) WiFi band. The uniqueness about the system is that it only uses single antenna for both sensing and communication. The algorithm works at application layer that controls the RF switch and antenna patterns at physical layer. Thus, the entire middle protocol layers are untouched. The system can easily be retrofitted to the existing nonadaptive communication systems.
Auteurs: Arpan Pal;Amit Mehta;Hasanga Goonesinghe;Dariush Mirshekar-Syahkal;Hisamatsu Nakano;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 02.-2018, volume: 66, issue:2, pages: 918 - 926
Editeur: IEEE
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» Consensus of Discrete-Time Linear Multiagent Systems With Communication, Input and Output Delays
Résumé:
This note addresses the output consensus problem of discrete-time heterogeneous linear multiagent systems with switching topology and time delays. Three types of time delays are considered: communication delays, input delays, and output delays. A distributed predictor-based controller is proposed and it is shown that the output consensus problem can be solved via the proposed controller. A key to the proof of our main results is the establishment of a new property of graphs, that is, uniform sequential connectivity and uniform quasi-strong connectivity are equivalent. A simulation example is provided to illustrate the effectiveness of our results.
Auteurs: Xiang Xu;Lu Liu;Gang Feng;
Apparue dans: IEEE Transactions on Automatic Control
Date publication: 02.-2018, volume: 63, issue:2, pages: 492 - 497
Editeur: IEEE
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» Consensus of Networked Euler–Lagrange Systems Under Time-Varying Sampled-Data Control
Résumé:
This paper is concerned with the consensus of multiple Euler–Lagrange systems with time-varying sampled-data control. Different from traditional sampled-data strategies, a time-varying sampled-data strategy is developed to realize the consensus of multiple Euler–lagrange systems, in which a function that can be distinct at different sampling instants is proposed to modulate the sampling interval. In addition, a new definition of average sampling interval, which is parallel to the average dwell time in switching control or average impulsive interval in impulsive control, is proposed to characterize the number of the updating of the sampling controller during some certain interval. The proposed average sampling interval makes our sampled-data strategy more suitable for a wide range of sampling signals. By utilizing the comparison principle, a sufficient criterion is obtained to guarantee the consensus of multiple Euler–Lagrange systems. The sufficient criterion is heavily dependent on the actual control duration time and the communication graph. Finally, a simulation example is presented to verify the applicability of the proposed results.
Auteurs: Wenbing Zhang;Yang Tang;Tingwen Huang;Athanasios V. Vasilakos;
Apparue dans: IEEE Transactions on Industrial Informatics
Date publication: 02.-2018, volume: 14, issue:2, pages: 535 - 544
Editeur: IEEE
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» Considering High-Performance Near-Field Reader Antennas: Comparisons of Proposed Antenna Layouts for Ultrahigh-Frequency Near-Field Radio-Frequency Identification
Résumé:
Radio-frequency identification (RFID) is being widely used in supply chain and logistics applications for wireless identification and the tracking and tracing of goods, with excellent performance for the long-range interrogation of tagged pallets and cases (up to 4-6 m, with passive tags). Item-level tagging (ILT) has also received much attention, especially in the pharmaceutical and retail industries. Low-frequency (125-134 KHz) and high-frequency (HF) (13.56 MHz) RFID systems have traditionally been used for ILT applications, where the radio-frequency (RF) power from the reader is delivered to the passive tags by inductive coupling. Recently, ultra-HF (UHF) (840-960 MHz) near-field (NF) RFID systems [1] have attracted increasing attention because of the merits of the much higher reading speed and capability to detect a larger number of tags (bulk reading). A UHF NF RFID system is a valuable solution to implement a reliable short-range wireless link (up to a few tens of centimeters) for ILT applications. Because the tags can be made smaller, RFID-based applications can be extended to extremely minuscule items (e.g., retail apparel, jewelry, drugs, rented apparel) as well as the successful implementation of RFID-based storage spaces, smart conveyor belts, and shopping carts.
Auteurs: Andrea Michel;Paolo Nepa;Xianming Qing;Zhi Ning Chen;
Apparue dans: IEEE Antennas and Propagation Magazine
Date publication: 02.-2018, volume: 60, issue:1, pages: 14 - 26
Editeur: IEEE
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» Consistency of Long-Term Subdural Electrocorticography in Humans
Résumé:
Objective: Subdural electrocorticography (ECoG) can provide a robust control signal for a brain–computer interface (BCI). However, the long-term recording properties of ECoG are poorly understood as most ECoG studies in the BCI field have only used signals recorded for less than 28 days. We assessed human ECoG recordings over durations of many months to investigate changes to recording quality that occur with long-term implantation. Methods: We examined changes in signal properties over time from 15 ambulatory humans who had continuous subdural ECoG monitoring for 184–766 days. Results: Individual electrodes demonstrated varying changes in frequency power characteristics over time within individual patients and between patients. Group level analyses demonstrated that there were only small changes in effective signal bandwidth and spectral band power across months. High-gamma signals could be recorded throughout the study, though there was a decline in signal power for some electrodes. Conclusion: ECoG-based BCI systems can robustly record high-frequency activity over multiple years, albeit with marked intersubject variability. Significance: Group level results demonstrated that ECoG is a promising modality for long-term BCI and neural prosthesis applications.
Auteurs: Ewan S. Nurse;Sam E. John;Dean R. Freestone;Thomas J. Oxley;Hoameng Ung;Samuel F. Berkovic;Terence J. O'Brien;Mark J. Cook;David B. Grayden;
Apparue dans: IEEE Transactions on Biomedical Engineering
Date publication: 02.-2018, volume: 65, issue:2, pages: 344 - 352
Editeur: IEEE
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» Consolidate IoT Edge Computing with Lightweight Virtualization
Résumé:
Lightweight virtualization (LV) technologies have refashioned the world of software development by introducing flexibility and new ways of managing and distributing software. Edge computing complements today's powerful centralized data centers with a large number of distributed nodes that provide virtualization close to the data source and end users. This emerging paradigm offers ubiquitous processing capabilities on a wide range of heterogeneous hardware characterized by different processing power and energy availability. The scope of this article is to present an in-depth analysis on the requirements of edge computing from the perspective of three selected use cases that are particularly interesting for harnessing the power of the Internet of Things. We discuss and compare the applicability of two LV technologies, containers and unikernels, as platforms for enabling the scalability, security, and manageability required by such pervasive applications that soon may be part of our everyday lives. To inspire further research, we identify open problems and highlight future directions to serve as a road map for both industry and academia.
Auteurs: Roberto Morabito;Vittorio Cozzolino;Aaron Yi Ding;Nicklas Beijar;Jorg Ott;
Apparue dans: IEEE Network
Date publication: 02.-2018, volume: 32, issue:1, pages: 102 - 111
Editeur: IEEE
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» Consumer Behavior: Why Engineers Need to Read About It [Guest Editorial]
Résumé:
Energy involves everybody. Current changes in energy and power systems, including the distributed production of renewables, an increasing need for flexibility of operations, and energy storage and transmission, affect consumers in one way or another. Changes often require the active participation and support of consumers, who may become prosumers. All the new systems and technologies developed by electrical engineers may influence consumer behavior and trigger positive or negative responses. Hence, it is important for electrical engineers to understand how their work may affect consumers, which behavior changes their solutions involve, and which consumer needs and preferences must be considered when developing new technology. This issue encourages a conversation among electrical engineers and social scientists and facilitates the integration of their different expertise.
Auteurs: Geertje Schuitema;Linda Steg;Mark O'Malley;
Apparue dans: IEEE Power and Energy Magazine
Date publication: 02.-2018, volume: 16, issue:1, pages: 14 - 18
Editeur: IEEE
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» Contactor Modeling Technology Based on an Artificial Neural Network
Résumé:
We propose a new contactor modeling method that incorporates the back propagation (BP) neural network to map the complex nonlinear electromechanical coupling relation of the contactor to build its model. First, the artificial neural network (ANN) model collects the actual operational data of the contactor, including the coil voltage, coil current and moving core displacement, and then uses the strong nonlinear fitting ability of the BP neural network to perform the model training. When the training is completed, the ANN model can output the precise displacement according to the input data of the coil voltage and the coil current. Through a simple training process, this method can complete the modeling of any electromagnetic contactor. This method avoids the need to solve the complex magnetic circuit equation of the contactor and thus provides a simple and universal method for calculating the displacement of the electromagnetic switch. The co-simulation system is used to model, train, and analyze the contactor ANN model. Finally, a relevant experiment is conducted to confirm the effectiveness of the ANN model.
Auteurs: Tang Longfei;Xu Zhihong;Bala Venkatesh;
Apparue dans: IEEE Transactions on Magnetics
Date publication: 02.-2018, volume: 54, issue:2, pages: 1 - 8
Editeur: IEEE
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» Context-Based Fractional Sample Refinement for HEVC Compliant Encoding
Résumé:
The H.265/MPEG-H High Efficiency Video Coding compliant encoding process faces the challenge of high computational complexity. Particularly, in the case of inter-picture prediction, most of the computational resources are allocated for the motion estimation (ME) process. In turn, ME and motion compensation enable improving coding efficiency by addressing the blocks of video frames as corresponding displacements from one or more reference blocks. These displacements do not necessarily have to be limited to integer sample positions, but may have an accuracy of half sample or quarter sample positions, which are identified during fractional sample refinement. In this paper, a context-based scheme for fractional sample refinement is proposed. The scheme takes the advantage of already obtained information in prior ME steps and provides significant flexibility in terms of parameterization. In this way, it adaptively achieves a desired tradeoff between computational complexity and coding efficiency. According to the experimental results obtained for an example algorithm utilizing the proposed framework, a significant decrease in the number of search points can be achieved. For instance, considering only 6 instead of 16 fractional sample positions results in a tradeoff of only 0.4% Bjøntegaard Delta-rate loss for high-definition video sequences compared with the conventional interpolation-and-search method.
Auteurs: Georg Maier;Benjamin Bross;Dan Grois;Detlev Marpe;Heiko Schwarz;Remco C. Veltkamp;Thomas Wiegand;
Apparue dans: IEEE Transactions on Circuits and Systems for Video Technology
Date publication: 02.-2018, volume: 28, issue:2, pages: 528 - 539
Editeur: IEEE
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» Continuous-Time Delta-Sigma Modulators With Time-Interleaved FIR Feedback
Résumé:
The use of a single-bit quantizer in a wideband CT $Delta Sigma text{M}$ is attractive, as the quantizer can be implemented in a power and area-efficient manner. Unfortunately, 1-bit CT $Delta Sigma $ Ms are plagued by a host of difficulties. Clock jitter and quantizer metastability are particularly problematic, and the higher loop filter linearity needed to process the full-scale feedback waveform results in increased power dissipation. The use of a finite impulse response (FIR) feedback DAC is a power efficient way of addressing the challenges above. However, even this technique runs into difficulties at multi-GHz clock rates. This paper introduces the idea of time-interleaved (TI) FIR feedback to enhance the performance of a conventional FIR DAC. A single-bit CT $Delta Sigma text{M}$ that uses a $2times $ TI-FIR DAC achieves 67.6/68.8/76 dB SNDR/SNR/DR in a 60 MHz bandwidth. Designed in a low leakage 65 nm CMOS process, the modulator operates at 6 GHz and occupies only 0.07 mm2. Its Walden Figure of Merit is 56.5 fJ/lvl.
Auteurs: Ankesh Jain;Shanthi Pavan;
Apparue dans: IEEE Transactions on Circuits and Systems I: Regular Papers
Date publication: 02.-2018, volume: 65, issue:2, pages: 434 - 443
Editeur: IEEE
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» Controllable Thermal-Frequency Tuning of a Terahertz Gyrotron
Résumé:
Gyrotron performance is sensitive to cavity structure parameters, and the cavity shape is temperature dependent due to thermal deformation induced by temperature rise from ohmic loss power on finite-conductivity cavity wall. Accordingly, this paper studies a frequency-tuning scheme for terahertz gyrotron by properly controlling the cavity thermal deformation. By combining gyrotron nonlinear theory and finite-element method software, controllable thermal-frequency-tuning capability of a continuous-wave 263-GHz gyrotron is systematically investigated, toward maintaining gyrotron operating under gyromonotron condition in frequency-tuning band, and achieving high efficiency in broadband frequency-tuning range. After studying cavity thermal distribution, structure deformation, and electron beam–wave interaction, an optimized cavity structure with transition sections on both ends is proposed. Simulation predicts that with the two-transition-section cavity, via additional thermal tuning, the continuous-frequency-tuning band is capable of reaching 1.75 GHz, which is 5 times of the initial bandwidth. Furthermore, using the thermal-frequency-tuning technology, impressive high efficiency above 17% is obtainable in the whole frequency-tuning range.
Auteurs: Li Luo;Chao-Hai Du;Xiang-Bo Qi;Zheng-Di Li;Shi Pan;Ming-Guang Huang;Pu-Kun Liu;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 02.-2018, volume: 65, issue:2, pages: 695 - 703
Editeur: IEEE
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» Convergence of Asynchronous Distributed Gradient Methods Over Stochastic Networks
Résumé:
We consider distributed optimization problems in which a number of agents are to seek the global optimum of a sum of cost functions through only local information sharing. In this paper, we are particularly interested in scenarios, where agents are operating asynchronously over stochastic networks subject to random failures. Most existing algorithms require coordinated and decaying stepsizes to ensure zero gap between the estimated value of each agent and the exact optimum, restricting it from asynchronous implementation and resulting in slower convergence results. To deal with this issue, we develop a new asynchronous distributed gradient method (AsynDGM) based on consensus theory. The proposed algorithm not only allows for asynchronous implementation in a completely distributed manner but also, most importantly, is able to seek the exact optimum even with constant stepsizes. We will show that the assumption of boundedness of gradients, which is widely used in the literature, can be dropped by instead imposing the standard Lipschitz continuity condition on gradients. Moreover, we derive an upper bound of stepsize within which the proposed AsynDGM can achieve a linear convergence rate for strongly convex functions with Lipschitz gradients. A canonical example of sensor fusion problems is provided to illustrate the effectiveness of the proposed algorithm.
Auteurs: Jinming Xu;Shanying Zhu;Yeng Chai Soh;Lihua Xie;
Apparue dans: IEEE Transactions on Automatic Control
Date publication: 02.-2018, volume: 63, issue:2, pages: 434 - 448
Editeur: IEEE
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» Converse Bounds on Modulation-Estimation Performance for the Gaussian Multiple-Access Channel
Résumé:
This paper focuses on the problem of separately modulating and jointly estimating two independent continuous-valued parameters sent over a Gaussian multiple-access channel (MAC) under the mean square error (MSE) criterion without bandwidth constraints. To this end, we first improve an existing lower bound on the MSE that is obtained using the parameter modulation-estimation techniques for the single-user additive white Gaussian noise (AWGN) channel. As for the main contribution of this paper, this improved modulation-estimation analysis is generalized to the model of the two-user Gaussian MAC. We present outer bounds to the achievable region in the plane of the MSE’s of the two user parameters, which provides a trade-off between the MSE’s, where we used zero-rate lower bounds on the error probability of Gaussian channels by Shannon and Polyanskiy et al. Numerical results showed that, the multi-user adaptation of the zero-rate lower bound by Polyanskiy et al. provides a tighter overall lower bound on the MSE pairs than the classical Shannon bound. In addition, we introduced upper bounds on the MSE exponents, namely, the exponential decay rates of these MSE’s in the asymptotic regime of long blocks that could make use of any bound on the error exponent of a single-user AWGN channel. The obtained results are numerically evaluated for three different bounds on the reliability function of the Gaussian channel. It is shown that the adaptation of the reliability function by Ashikhmin et al. to the MAC provides a significantly tighter characterization than Shannon’s sphere-packing bound and the divergence bound.
Auteurs: Ayşe Ünsal;Raymond Knopp;Neri Merhav;
Apparue dans: IEEE Transactions on Information Theory
Date publication: 02.-2018, volume: 64, issue:2, pages: 1217 - 1230
Editeur: IEEE
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» Conversion of 230 kV Switchyard to Gas-Insulated Substation in a Gas Plant
Résumé:
Frequent failures and increased maintenance in a 30-year old 230 kV air-insulated switchyard (AIS) of a large gas plant caused the existing installation to be unreliable to provide uninterrupted power supply to critical plant operations. The replacement parts from original equipment manufacturers became scarce and expensive. The maintenance activities in severe and extremely hot middle-east weather conditions were cumbersome and time-consuming. A planned plant expansion with considerable incremental load to the facility provided an opportunity for a review of the complete electrical system. After a thorough review, it was decided to convert the main outdoor AIS to an indoor gas-insulated switchgear (GIS) substation to support the existing and new facilities. However, a total loss of power to the continuous operation of this critical gas facility was unacceptable. The existing switchyard with an energized 230 kV open bus system had limited space to safely perform the demolition and construction activities for the new GIS. Detailed analysis of the installation options, construction techniques, safety requirements, and logistical methods was performed to eliminate potential for any total loss of power. The construction activity involved interfacing with two separate redundant power supply sources, with separate transmission line protection systems and equipment. The parties involved worked together in reaching an agreement on engineering, procurement, installation, testing, and commissioning activities that would successfully implement this transition without any loss of power to the gas production facilities.
Auteurs: Merwyn D'Souza;Saud Al-Shammari;Mghwar Safwa;
Apparue dans: IEEE Transactions on Industry Applications
Date publication: 02.-2018, volume: 54, issue:1, pages: 895 - 904
Editeur: IEEE
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» Convolutional Invasion and Expansion Networks for Tumor Growth Prediction
Résumé:
Tumor growth is associated with cell invasion and mass-effect, which are traditionally formulated by mathematical models, namely reaction-diffusion equations and biomechanics. Such models can be personalized based on clinical measurements to build the predictive models for tumor growth. In this paper, we investigate the possibility of using deep convolutional neural networks to directly represent and learn the cell invasion and mass-effect, and to predict the subsequent involvement regions of a tumor. The invasion network learns the cell invasion from information related to metabolic rate, cell density, and tumor boundary derived from multimodal imaging data. The expansion network models the mass-effect from the growing motion of tumor mass. We also study different architectures that fuse the invasion and expansion networks, in order to exploit the inherent correlations among them. Our network can easily be trained on population data and personalized to a target patient, unlike most previous mathematical modeling methods that fail to incorporate population data. Quantitative experiments on a pancreatic tumor data set show that the proposed method substantially outperforms a state-of-the-art mathematical model-based approach in both accuracy and efficiency, and that the information captured by each of the two subnetworks is complementary.
Auteurs: Ling Zhang;Le Lu;Ronald M. Summers;Electron Kebebew;Jianhua Yao;
Apparue dans: IEEE Transactions on Medical Imaging
Date publication: 02.-2018, volume: 37, issue:2, pages: 638 - 648
Editeur: IEEE
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» Convolutional Sparse Learning for Blind Deconvolution and Application on Impulsive Feature Detection
Résumé:
The mechanical structure or transmission path between fault source and sensor location always distorts the impulsive signatures of machine faults. It is thus an important task to estimate the desired impulsive feature and the influence of transmission path simultaneously from the noisy observation signals. Therefore, a convolutional sparse learning model (ConvSLM) is proposed to perform impulsive feature detection. The ConvSLM directly models the modulation process of the transmission path and is completely different from the indirect inverse filter design scheme as popular deconvolution techniques adopted. Meanwhile, to overcome the inherent drawbacks of the popular Kurtosis maximization strategy, the sparse structure of the impulsive feature is integrated into the objective function of the ConvSLM. Different from the recently developed two-stage solver, a new iterative algorithm with only one stage is also developed under a multiple-block nonconvex alternating direction method of multiplier framework to cope with the nonconvexity and nonsmoothness of the sparsity-regularized objective function, which not only reduces the algorithmic complexity but also has a convergence guarantee. Numerical experiments on synthetic data and test results corroborate the efficacy of the advocated approach. Compared with the state-of-the-art blind deconvolution techniques, the ConvSLM’s superiority is sufficiently verified through its application on the impulsive detection of the wind turbine gearbox gear.
Auteurs: Zhaohui Du;Xuefeng Chen;Han Zhang;
Apparue dans: IEEE Transactions on Instrumentation and Measurement
Date publication: 02.-2018, volume: 67, issue:2, pages: 338 - 349
Editeur: IEEE
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» Cooperative Low-Power Wideband Sensing Based on 1-bit Quantization
Résumé:
We propose a cooperative wideband sensing approach based on the fast Fourier transform-based 1-bit quantization sensing applied at the cognitive radio (CR) receiver. A hard combining approach is utilized to fuse the local binary decisions obtained from different CRs. The system parameters are optimized to maximize the aggregate throughput subjected to a constrained interference term. When compared with other methods, in addition to the significant saving in power and complexity, results indicate that the proposed method provides better performance even though an aggressive quantization has been applied.
Auteurs: Abdelmohsen Ali;Walaa Hamouda;
Apparue dans: IEEE Communications Letters
Date publication: 02.-2018, volume: 22, issue:2, pages: 368 - 371
Editeur: IEEE
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» Cooperative Output Regulation of Linear Multi-Agent Systems by Intermittent Communication: A Unified Framework of Time- and Event-Triggering Strategies
Résumé:
This paper addresses the cooperative output regulation problem of heterogeneous linear multi-agent systems with directed communication topologies, requiring only intermittent communication. First, we propose a unified framework of time- and event-triggering strategies. Then based on the unified triggering framework, a novel triggering mechanism utilizing the self-triggering strategy is developed. It is shown that with the proposed triggering mechanism, the cooperative output regulation problem can be solved by a distributed control law with only intermittent communication. It is further shown that with the unified framework of time- and event-triggering strategies for each agent, a positive minimum inter-event time can be explicitly given and Zeno behavior can be thus excluded. An example is finally provided to demonstrate the effectiveness of the proposed controller and the triggering mechanism.
Auteurs: Wenfeng Hu;Lu Liu;Gang Feng;
Apparue dans: IEEE Transactions on Automatic Control
Date publication: 02.-2018, volume: 63, issue:2, pages: 548 - 555
Editeur: IEEE
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» Cooperative Spectrum Sensing Under Ambient Malicious Interferences
Résumé:
The presence of malicious interferences in cognitive radio networks can severely degrade the performance of spectrum sensing. In this letter, we propose a cooperative spectrum sensing approach to tackle malicious interferences, where the local signal to interference plus noise power ratios at secondary users are transmitted to a fusion center for making decision. The theoretical performance of the proposed detector, in terms of false-alarm and detection probabilities, is analyzed, and simulation results are provided to validate the theoretical analyses and demonstrate the superior performance of the detector.
Auteurs: Mingyang Sun;Ming Jin;Qinghua Guo;Youming Li;
Apparue dans: IEEE Communications Letters
Date publication: 02.-2018, volume: 22, issue:2, pages: 432 - 435
Editeur: IEEE
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» Coplanar-Electrodes-Based Differential Structure for Piezoresistive Sensor Made of Carbon Nanotube Filled Silicone Rubber Composite
Résumé:
To develop the differential piezoresistive sensor made of carbon nanotube filled silicone rubber composite with concise configuration, a coplanar-electrodes-based differential structure is designed. The structure includes two composite films with high carbon nanotube content (12 vol.%) and two composite films with low carbon nanotube content (4 vol.%). All the electrodes for the four composite films are located in the same encapsulation layer (i.e., all the electrodes are located on the same side of the composite films), which can simplify the configuration of the sensor probe. The electrical resistance of the composite film with high/low carbon nanotube content decreases/increases with the increase of the compressive pressure and increases with the increase of the temperature. The two composite films with high carbon nanotube contents are placed on the two diagonal arms of an electrical bridge, and the other two composite films with low carbon nanotube contents are placed on the other two diagonal arms of the bridge. The experimental results verify the feasibility of using the coplanar-electrodes-based differential structure to reduce the output drift induced by the temperature and improve the sensitivity.
Auteurs: Luheng Wang;Fei Wu;Yalin Wang;
Apparue dans: IEEE Sensors Journal
Date publication: 02.-2018, volume: 18, issue:4, pages: 1403 - 1409
Editeur: IEEE
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» Corona Current Coupling in Bipolar HVDC and Hybrid HVAC/HVDC Overhead Lines
Résumé:
This paper investigates the corona generated ion-flow environment in bipolar HVdc and hybrid ac/dc transmission systems. The emphasis is on the dc ion current magnitude in the conductors. In dc conductors, this constitutes the corona power loss, while in ac conductors, this quantity is primarily of concern due to the risk of transformer saturation. Existing prediction methods are compared to full-scale test data from the literature and new laboratory measurements. It is shown that the bipolar HVdc and hybrid ac/dc ion-flow phenomena are similar in the sense that mutual space-charge-related surface field enhancements are a dominant factor in the determination of the total conductor ion currents. Furthermore, in a hybrid ac/dc environment, the existence of a net dc ion current stemming from the ac conductor is verified and explained. Limitations of existing prediction methods are demonstrated and recommendations for future work is given.
Auteurs: Martin Pfeiffer;Sören Hedtke;Christian M. Franck;
Apparue dans: IEEE Transactions on Power Delivery
Date publication: 02.-2018, volume: 33, issue:1, pages: 393 - 402
Editeur: IEEE
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» Corrections to “TOPSIS-Based Nonlinear-Programming Methodology for Multi-attribute Decision Making With Interval-Valued Intuitionistic Fuzzy Sets”
Résumé:
There are some mistakes in the computation results of the real example in the article by Li, “TOPSIS-based nonlinear-programming methodology for multi-attribute decision making with interval-valued intuitionistic fuzzy sets” [IEEE Trans. Fuzzy Syst., vol. 18, no. 2, pp. 299–311, 2010], and this article provides corrections to that paper.
Auteurs: Jia-Cai Liu;Deng-Feng Li;
Apparue dans: IEEE Transactions on Fuzzy Systems
Date publication: 02.-2018, volume: 26, issue:1, pages: 391 - 391
Editeur: IEEE
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» Corrections to “In Situ Oxide, GaN Interlayer-Based Vertical Trench MOSFET (OG-FET) on Bulk GaN Substrates’
Résumé:
In the above paper [1], the fifth author’s name was printed incorrectly. The correct name is Junqian Liu.
Auteurs: Chirag Gupta;Cory Lund;Silvia H. Chan;Anchal Agarwal;Junqian Liu;Yuuki Enatsu;Stacia Keller;Umesh K. Mishra;
Apparue dans: IEEE Electron Device Letters
Date publication: 02.-2018, volume: 39, issue:2, pages: 316 - 316
Editeur: IEEE
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» Corrections to “Compact Filtering Rat-Race Hybrid With Wide Stopband”
Résumé:
There are some typos in [1, eqs. (2), (3), (7), (10), (11), (15), (17), and (25)]. They should be corrected as follows:
Auteurs: Kai-Xu Wang;Xiu Yin Zhang;Shao Yong Zheng;Quan Xue;
Apparue dans: IEEE Transactions on Microwave Theory and Techniques
Date publication: 02.-2018, volume: 66, issue:2, pages: 1142 - 1143
Editeur: IEEE
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» Corrections to “Deep Recurrent Neural Networks for Hyperspectral Image Classification”
Résumé:
Here, we correct some errors caused by a programming bug (a data type error) in overall accuracies (OAs) reported in [1]. The corrected OAs are underlined and shown in bold in Tables IIII.
Auteurs: Lichao Mou;Pedram Ghamisi;Xiao Xiang Zhu;
Apparue dans: IEEE Transactions on Geoscience and Remote Sensing
Date publication: 02.-2018, volume: 56, issue:2, pages: 1214 - 1215
Editeur: IEEE
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» Corrections to “Gysel Power Divider With Arbitrary Power Ratios and Filtering Responses Using Coupling Structure”
Résumé:
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Auteurs: Kai-Xu Wang;Xiu Yin Zhang;Bin-Jie Hu;
Apparue dans: IEEE Transactions on Microwave Theory and Techniques
Date publication: 02.-2018, volume: 66, issue:2, pages: 1144 - 1144
Editeur: IEEE
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» Corrections to “Problematic Projection to the In-Sample Subspace for a Kernelized Anomaly Detector”
Résumé:
In the above paper [1], there are several errors, which we correct here.
Auteurs: James Theiler;Guen Grosklos;
Apparue dans: IEEE Geoscience and Remote Sensing Letters
Date publication: 02.-2018, volume: 15, issue:2, pages: 307 - 307
Editeur: IEEE
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» Corrections to “Segment-Oriented Depiction and Analysis for Hyperspectral Image Data”
Résumé:
In [1], information regarding the corresponding author is missing. The information is updated here. The updated footnote below shows that Xiaoyan Luo is the corresponding author for this paper.
Auteurs: Jihao Yin;Hui Qv;Xiaoyan Luo;Xiuping Jia;
Apparue dans: IEEE Transactions on Geoscience and Remote Sensing
Date publication: 02.-2018, volume: 56, issue:2, pages: 1213 - 1213
Editeur: IEEE
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» Corrections to “Toward Near-Ground Localization: Modeling and Applications for TOA Ranging Error”
Résumé:
The authors of [1] would like to make the following corrections.
Auteurs: Cheng Xu;Jie He;Xiaotong Zhang;Po-Hsuan Tseng;Shihong Duan;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 02.-2018, volume: 66, issue:2, pages: 1052 - 1052
Editeur: IEEE
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» Cost-Effective Gap Waveguide Technology Based on Glide-Symmetric Holey EBG Structures
Résumé:
We present a novel electromagnetic bandgap (EBG) structure, which can be used to manufacture low-cost waveguiding structures at high frequencies. The unit cell of the proposed EBG consists of glide-symmetric holes in parallel plate waveguide. Using this unit cell in groove gap waveguide technology has a number of advantages over pin-type EBG at high frequencies, such as acquiring higher accuracy because of larger periodicity as well as an easier and cheaper manufacturing process. The performance of the proposed waveguiding structure is demonstrated using both a straight and a double 90° bent lines through simulation and measurement.
Auteurs: Mahsa Ebrahimpouri;Eva Rajo-Iglesias;Zvonimir Sipus;Oscar Quevedo-Teruel;
Apparue dans: IEEE Transactions on Microwave Theory and Techniques
Date publication: 02.-2018, volume: 66, issue:2, pages: 927 - 934
Editeur: IEEE
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» CR-SDVN: A Cognitive Routing Protocol for Software-Defined Vehicular Networks
Résumé:
Due to the highly dynamic nature of cognitive vehicular networks, several sporadic links induce a long delay in the network. The selection of a stable route is therefore one of the key design factors to improve overall network stability, thereby reducing the end-to-end delay. Software-defined networking (SDN) is a novel approach that improves network intelligence. To this end, we propose a novel SDN-based routing protocol for cognitive vehicular networks that finds a stable route between source and destination. As this is a cognitive routing protocol, spectrum sensing is therefore the primary task of this algorithm to improve network stability by keeping primary user activity safe. We apply a belief propagation algorithm for channel selection. This is an SDN-based vehicular communications scheme where two nodes can only communicate when they have consensus about a common idle channel. The protocol has two phases: the registering phase and the route prediction phase. The SDN main controller (MC) is responsible for a global view of the network, whereas several local controllers (LCs) are responsible for localized global views of the network. This layering of controllers into two kinds (MC and LCs) improves the network performance in terms of end-to-end delay, high delivery ratio, and low overhead. We prove this in our simulation results by comparing our proposed scheme with two existing schemes (one with, and another without, SDN).
Auteurs: Huma Ghafoor;Insoo Koo;
Apparue dans: IEEE Sensors Journal
Date publication: 02.-2018, volume: 18, issue:4, pages: 1761 - 1772
Editeur: IEEE
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» Crack-Free Silicon-Nitride-on-Insulator Nonlinear Circuits for Continuum Generation in the ${C}$ -Band
Résumé:
We report on the fabrication and testing of silicon-nitride-on-insulator nonlinear photonic circuits for complementary metal–oxide–semiconductor (CMOS) compatible monolithic co-integration with silicon-based optoelectronics. In particular, a process has been developed to fabricate low-loss crack-free Si3N4 730-nm-thick films for Kerr-based nonlinear functions featuring full process compatibility with existing silicon photonics and front-end Si optoelectronics. Experimental evidence shows that 2.1-cm-long nanowires based on such crack-free silicon nitride films are capable of generating a frequency continuum spanning 1515–1575 nm via self-phase modulation. This work paves the way to time-stable power-efficient Kerr-based broadband sources featuring full process compatibility with Si photonic integrated circuits on CMOS lines.
Auteurs: Houssein El Dirani;Marco Casale;Sébastien Kerdiles;Carole Socquet-Clerc;Xavier Letartre;Christelle Monat;Corrado Sciancalepore;
Apparue dans: IEEE Photonics Technology Letters
Date publication: 02.-2018, volume: 30, issue:4, pages: 355 - 358
Editeur: IEEE
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» CRITIC-Based Node Importance Evaluation in Skeleton-Network Reconfiguration of Power Grids
Résumé:
Seven centrality indexes are first presented for identifying important nodes with topological features of a complex network and electrical characteristics of a power system considered. Then, a criteria importance through intercriteria correlation-based multi-index decision-making method, in which entropy and the Spearman’s rank correlation coefficient are integrated for reflecting the differences and correlations among multiple indexes, respectively, is presented to comprehensively identify the importance degrees of nodes in a given power grid. Finally, the proposed indexes and method are applied to actual Guangdong power system in China, and the results are compared with those attained by single-attribute and multi-attribute evaluation methods.
Auteurs: Zhenzhi Lin;Fushuan Wen;Huifang Wang;Guanqiang Lin;Tianwen Mo;Xiaojun Ye;
Apparue dans: IEEE Transactions on Circuits and Systems II: Express Briefs
Date publication: 02.-2018, volume: 65, issue:2, pages: 206 - 210
Editeur: IEEE
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» Critical Link Analysis for Urban Transportation Systems
Résumé:
A fundamental and important step for safety analysis for an urban transportation system is to find its critical links. However, most approaches in the current literature focused on highway or intercity transportation systems. The key characteristics of urban transportation systems were not considered and the concept of criticality of links was mixed up with the concept of vulnerability. This paper defines the criticality of links from two perspectives, i.e., the vulnerability and potential, based on which a novel methodology for identifying critical links in an urban transportation network is proposed. This novel methodology includes a ranking method and a novel mesoscopic model to examine the urban transportation network performance. The mesoscopic model is a novel cell transmission model, which grasps key characteristics of an urban transportation network, such as dynamic demand generated on links, different link lengths, and intersection flow assignment. The method is validated by a real world case from Hong Kong. The simulation results indicate that the ranking of critical links depends on particular scenarios, available resources, and both supply and demand of the system; furthermore, two paradoxes are discovered and discussed.
Auteurs: Yaoming Zhou;Junwei Wang;
Apparue dans: IEEE Transactions on Intelligent Transportation Systems
Date publication: 02.-2018, volume: 19, issue:2, pages: 402 - 415
Editeur: IEEE
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