Electrical and Electronics Engineering publications abstract of: 01-2017 sorted by title, page: 4

» Closed-Form Jones Matrix of Dual-Polarized Inverted-Vee Dipole Antennas Over Lossy Ground
Abstract:
This paper presents a closed-form expression for the Jones matrix of a dual-polarized inverted-vee dipole antenna based on the Lorentz reciprocity theorem and the basic rules of electromagnetic refraction. The expression is used to determine the intrinsic cross-polarization ratio (IXR) as a function of droop angle, position of the source in the sky, antenna height, frequency, and reflection coefficient of the underlying ground. The expression is verified using full-wave simulations with a method-of-moments solver, showing very good agreement. It explains the increase in the IXR when the antenna is placed over a perfect electric ground plane. This result is used to explain the polarization properties of the Square Kilometre Array Log-periodic Antenna. Through the LOw-Frequency ARray Low-Band Antenna (LOFAR-LBA), the importance of the size of the ground plane is explained. Finally, design consideration for high polarization purity antennas is discussed.
Autors: Rene A. C. Baelemans;Adrian T. Sutinjo;Peter J. Hall;A. Bart Smolders;Michel J. Arts;Eloy de Lera Acedo;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Jan 2017, volume: 65, issue:1, pages: 26 - 35
Publisher: IEEE
 
» Closed-Form Orthogonal Ramanujan Integer Basis
Abstract:
In this letter, a closed-form orthogonal Ramanujan integer basis is proposed and obtained by performing Gram–Schmidt process from the Ramanujan sum and its circular shift. It has a surprisingly simple and sparse form, which is better than the original complete Ramanujan basis. The relationship between the original basis and proposed basis is also clearly illustrated. Therefore, the original basis can be replaced easily.
Autors: Soo-Chang Pei;Kuo-Wei Chang;
Appeared in: IEEE Signal Processing Letters
Publication date: Jan 2017, volume: 24, issue:1, pages: 1 - 1
Publisher: IEEE
 
» Cloud Attenuation Statistics Prediction From Ka-Band to Optical Frequencies: Integrated Liquid Water Content Field Synthesizer
Abstract:
The impact of cloud impairments on satellite links is increasing with the employment of higher frequency bands. In this paper, a model for predicting cloud attenuation statistics for satellite communication systems operating from -band to optical range is presented. The cloud attenuation must be accurately quantified for the reliable design of satellite communication systems. A stochastic dynamic model for the generation of integrated liquid water content (ILWC) fields is proposed. The model is based on the stochastic differential equations and incorporates the spatial and temporal behavior of ILWC. Classifying the cloud types based on the cloud vertical extent and using the microphysical properties of clouds, the well-known Mie scattering theory and the global statistics for ILWC by International Telecommunications Union–Radio (ITU-R), a unified space-time model for the prediction of induced attenuation due to clouds for frequencies above -band up to optical range is presented. The proposed model is tested in terms of first order statistics, compared first with ITU-R P.840-6 model and then with data obtained in the literature, showing encouraging results. Moreover, the probability of cloud occurrence for optical satellite single and site diversity system is calculated. Finally, the limitations and the applicability of the proposed model are discussed.
Autors: Nikolaos K. Lyras;Charilaos I. Kourogiorgas;Athanasios D. Panagopoulos;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Jan 2017, volume: 65, issue:1, pages: 319 - 328
Publisher: IEEE
 
» Clustering-Based Spectrum Sharing Strategy for Cognitive Radio Networks
Abstract:
In this paper, we propose a clustering-based resource allocation (RA) scheme for the multiuser orthogonal frequency division multiplexing (OFDM)-based cognitive radio network, where we aim to maximize the sum capacity of the secondary users (SUs) subject to practical constraints in wireless environment. Our general RA optimization task leads to a challenging mixed integer programming problem that is computationally intractable. We first introduce a simple and efficient clustering method to divide all the SUs into multiple groups based on their mutual interference degrees, where the SUs in different groups can share the same OFDM subchannels to improve spectrum utilization efficiency, while the SUs with heavy mutual interference cluster together in the same group and employ different subchannels to alleviate their mutual interference. Then we develop efficient radio RA algorithms to maximize the sum rate of the SUs in each cluster. A user-oriented subchannel assignment method is presented to remove the awkward integer constraints of the formulated RA problem, followed by a fast power distribution algorithm that can work out optimal solutions with an approximate linear complexity. Simulation results indicate that our proposed RA scheme can improve the throughput of the SUs significantly as compared with other methods. Moreover, our proposed RA algorithms converge stably and quickly.
Autors: Jingyi Dai;Shaowei Wang;
Appeared in: IEEE Journal on Selected Areas in Communications
Publication date: Jan 2017, volume: 35, issue:1, pages: 228 - 237
Publisher: IEEE
 
» Clutter Rank Estimation for Reduce-Dimension Space-Time Adaptive Processing MIMO Radar
Abstract:
Estimation of clutter rank in the reduce-dimension (RD) domain has great importance for RD space-time adaptive processing (STAP) algorithms. In this letter, clutter rank estimation rules of RD STAP algorithms for multiple input multiple output (MIMO) radar with different parameters are developed. The accuracy of the proposed rules is verified and the way to design RD MIMO STAP processor under the guidance of the proposed rules is presented.
Autors: Weike Feng;Yongshun Zhang;Xingyu He;
Appeared in: IEEE Sensors Journal
Publication date: Jan 2017, volume: 17, issue:2, pages: 238 - 239
Publisher: IEEE
 
» CMOS Integrated Remote Antenna Unit for Fiber-Fed Distributed MIMO Systems
Abstract:
A fully integrated remote antenna unit (RAU) intended for fiber-fed distributed multiple-input multiple-output systems is presented. The circuit is designed for narrowband (60 MHz) time-division duplex systems, where an IF over fiber approach is chosen to facilitate the use of low-cost optical components and integrated photodetectors. A novel antenna switch control scheme is introduced, which enables the use of an integrated antenna switch instead of a bulky off chip circulator. The reference frequency signal is distributed in the fiber together with user data and used by a phase-locked-loop-based frequency synthesizer to generate the local oscillator signal inside the RAU, hence synchronizing all RAUs of the distributed antenna system. At an operating frequency of 2.1 GHz, the measured optical-to-electrical conversion gain of the downlink is 71.7 dB, the error vector magnitude is 3.2%, and the adjacent channel leakage ratio is 39.2 dBc at an output power of +3 dBm for a 16-quadrature amplitude modulation (16-QAM) long-term evolution downlink signal. The uplink has a gain of 32.5 dB, a noise figure of 3.5 dB, and an in-band third-order intercept point of −12 dBm. Implemented in a standard 65-nm CMOS process, the complete RAU occupies just 2 mm2 of die area and consumes 146 mW during downlink signal transmission and 122 mW during uplink signal reception.
Autors: Waqas Ahmad;Mohammed Abdulaziz;Anders Nejdel;Markus Törmänen;Henrik Sjöland;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Jan 2017, volume: 65, issue:1, pages: 173 - 186
Publisher: IEEE
 
» Co-Primary Spectrum Sharing for Inter-Operator Device-to-Device Communication
Abstract:
The business potential of device-to-device (D2D) communication including public safety and vehicular communications will be realized only if direct communication between devices subscribed to different mobile operators (OPs) is supported. One possible way to implement inter-operator D2D communication may use the licensed spectrum of the OPs, i.e., OPs agree to share spectrum in a co-primary manner, and inter-operator D2D communication is allocated over spectral resources contributed from both parties. In this paper, we consider a spectrum sharing scenario, where a number of OPs construct a spectrum pool dedicated to support inter-operator D2D communication. OPs negotiate in the form of a non-cooperative game about how much spectrum each OP contributes to the spectrum pool. OPs submit proposals to each other in parallel until a consensus is reached. When every OP has a concave utility function on the box-constrained region, we identify the conditions guaranteeing the existence of a unique equilibrium point. We show that the iterative algorithm based on the OP’s best response might not converge to the equilibrium point due to myopically overreacting to the response of the other OPs, while the Jacobi-play strategy update algorithm can converge with an appropriate selection of update parameter. Using the Jacobi-play update algorithm, we illustrate that asymmetric OPs contribute an unequal amount of resources to the spectrum pool; however, all participating OPs may experience significant performance gains compared with the scheme without spectrum sharing.
Autors: Byungjin Cho;Konstantinos Koufos;Riku Jäntti;Seong-Lyun Kim;
Appeared in: IEEE Journal on Selected Areas in Communications
Publication date: Jan 2017, volume: 35, issue:1, pages: 91 - 105
Publisher: IEEE
 
» CO2/CO concentration ratio: A complementary method for determining the degree of polymerization of power transformer paper insulation
Abstract:
Since power transformers are valuable components of power networks, reliable determination of the remaining lifetime of a transformer is very important for power utilities. Power transformers consist of oil, a core, wire, and paper (cellulose), and their performance and remaining useful lifetime depend on the state of the oil-impregnated paper. Changing the oil over the lifetime of a transformer is possible, but it is not possible to change the insulation paper. Thus, the end of the paper lifetime will also be the end of the transformer lifetime (typically more than 40 years). The health condition of an in-service power transformer can be assessed by chemical and electrical tests of the oil and the paper [1].
Autors: Ashkan Teymouri;Behrooz Vahidi;
Appeared in: IEEE Electrical Insulation Magazine
Publication date: Jan 2017, volume: 33, issue:1, pages: 24 - 30
Publisher: IEEE
 
» Codebook Design for Millimeter-Wave Channel Estimation With Hybrid Precoding Structure
Abstract:
In this paper, we study hierarchical codebook design for channel estimation in millimeter-wave (mmWave) communications with a hybrid precoding structure. Due to the limited saturation power of the mmWave power amplifier, we consider the per-antenna power constraint (PAPC). We first propose a metric, termed generalized detection probability (GDP), to evaluate the quality of an arbitrary codeword. This metric not only enables an optimization approach for mmWave codebook design, but also can be used to compare the performance of two different codewords/codebooks. To the best of our knowledge, GDP is the first such metric, particularly for mmWave codebook design. We then propose a heuristic approach to design a hierarchical codebook exploiting beam widening with the multi-RF-chain sub-array (BMW-MS) technique. To obtain crucial parameters of BMW-MS, we provide two solutions, namely, a low-complexity search (LCS) solution to optimize the GDP metric and a closed-form (CF) solution to pursue a flat beam pattern. Performance comparisons show that BMW-MS/LCS and BMW-MS/CF achieve very close performances, and they outperform the existing alternatives under the PAPC.
Autors: Zhenyu Xiao;Pengfei Xia;Xiang-Gen Xia;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Jan 2017, volume: 16, issue:1, pages: 141 - 153
Publisher: IEEE
 
» Coil Excited Pseudo Direct Drive Electrical Machines
Abstract:
A pseudo direct drive (PDD) equipped with a coil-excited high-speed (HS) rotor is presented. An analytical model which predicts the flux density in the air spaces and the permanent magnets (PMs) of the PDD is presented, and it is shown that good agreement exists between the analytical and finite-element predictions. Furthermore, the model is employed to investigate the effects of the key design parameters on the performance of a coil-excited PDD for a 10-MW wind turbine application, and an optimized design is proposed. It is shown that shear stress in excess of 100 kPa can be achieved, and that compared with a PM-excited PDD, a reduction in PM mass can be realized. It is also shown that the efficiency over the operating range of the wind turbine can be maximized by adopting an appropriate control strategy of the HS rotor excitation currents.
Autors: A. Penzkofer;G. Cooke;M. Odavic;K. Atallah;
Appeared in: IEEE Transactions on Magnetics
Publication date: Jan 2017, volume: 53, issue:1, pages: 1 - 11
Publisher: IEEE
 
» Collaborative Smartphone Sensing Using Overlapping Coalition Formation Games
Abstract:
With the rapid growth of sensor technology, smartphone sensing has become an effective approach to improve the quality of smartphone applications. However, due to time-varying wireless channels and lack of incentives for the users to participate, the quality and quantity of the data uploaded by the smartphone users are not always satisfying. In this paper, we consider a smartphone sensing system in which a platform publicizes multiple tasks, and the smartphone users choose a set of tasks to participate in. In the traditional non-cooperative approach with incentives, each smartphone user gets rewards from the platform as an independent individual and the limit of the wireless channel resources is often omitted. To tackle this problem, we introduce a novel cooperative approach with an overlapping coalition formation game (OCF-game) model, in which the smartphone users can cooperate with each other to form the overlapping coalitions for different sensing tasks. We also utilize a centralized case to describe the upper bound of the system sensing performance. Simulation results show that the cooperative approach achieves a better performance than the non-cooperative one in various situations.
Autors: Boya Di;Tianyu Wang;Lingyang Song;Zhu Han;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: Jan 2017, volume: 16, issue:1, pages: 30 - 43
Publisher: IEEE
 
» Collective First-Person Vision for Automatic Gaze Analysis in Multiparty Conversations
Abstract:
This paper targets small- to medium-sized-group face-to-face conversations where each person wears a dual-view camera, consisting of inward- and outward-looking cameras, and presents an almost fully automatic but accurate ofline gaze analysis framework that does not require users to perform any calibration steps. Our collective first-person vision framework, where captured audio–visual signals are gathered and processed in a centralized system, jointly undertakes the fundamental functions required for group gaze analysis, including speaker detection, face tracking, and gaze tracking. Of particular note is our self-calibration of gaze trackers by exploiting a general conversation rule, namely that listeners are likely to look at the speaker. From the rough conversational prior knowledge, our system visualizes fine-grained participants’ gaze behavior as a gazee-centered heat map, which quantitatively reveals what parts of the gazee's body the participant looked at and for how long while the gazer was speaking or listening. An experiment using conversations amounting to a total of 140 min, each lasting an average of 8.7 min and engaged in by 37 participants in groups of three to six, achieves a mean absolute error of 2.8 in gaze tracking. A statistical test reveals neither a group size effect nor a conversation type effect. Our method achieves F-scores of over 0.89 and 0.87 in gazee and eye contact recognition, respectively, in comparison with human annotation.
Autors: Shiro Kumano;Kazuhiro Otsuka;Ryo Ishii;Junji Yamato;
Appeared in: IEEE Transactions on Multimedia
Publication date: Jan 2017, volume: 19, issue:1, pages: 107 - 122
Publisher: IEEE
 
» Color-Based Segmentation of Sky/Cloud Images From Ground-Based Cameras
Abstract:
Sky/cloud images captured by ground-based cameras (a.k.a. whole sky imagers) are increasingly used nowadays because of their applications in a number of fields, including climate modeling, weather prediction, renewable energy generation, and satellite communications. Due to the wide variety of cloud types and lighting conditions in such images, accurate and robust segmentation of clouds is challenging. In this paper, we present a supervised segmentation framework for ground-based sky/cloud images based on a systematic analysis of different color spaces and components, using partial least-squares regression. Unlike other state-of-the-art methods, our proposed approach is entirely learning based and does not require any manually defined parameters. In addition, we release the Singapore whole Sky imaging segmentation database, a large database of annotated sky/cloud images, to the research community.
Autors: Soumyabrata Dev;Yee Hui Lee;Stefan Winkler;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Jan 2017, volume: 10, issue:1, pages: 231 - 242
Publisher: IEEE
 
» Combining High Hole Concentration in p-GaN and High Mobility in u-GaN for High p-Type Conductivity in a p-GaN/u-GaN Alternating-Layer Nanostructure
Abstract:
p-GaN/u-GaN alternating-layer nanostructures are grown with molecular beam epitaxy to show a low p-type resistivity level of -cm. The obtained low resistivity is due to the high hole mobility in the u-GaN layers, which serve as effective transport channels of holes diffused from the neighboring p-GaN layers. The Mg doping in a thin p-GaN layer can lead to a high Mg-doping concentration for supplying holes to the neighboring u-GaN layers. Simulations based on a 1-D drift diffusion charge control model and the Brooks–Herring theory of ionized impurity scattering are undertaken to first obtain the depth-dependent distributions of hole concentration, mobility, and, hence, resistivity. Then, weighted averaging processes are used for evaluating the effective hole concentration, mobility, and resistivity of a p-GaN/u-GaN alternating-layer nanostructure to give consistent results with the measured data.
Autors: Hao-Tsung Chen;Chia-Ying Su;Charng-Gan Tu;Yu-Feng Yao;Chun-Han Lin;Yuh-Renn Wu;Yean-Woei Kiang;Chih-Chung C. C. Yang;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Jan 2017, volume: 64, issue:1, pages: 115 - 120
Publisher: IEEE
 
» Commencement of operation of the world's largest storage battery facility [News from Japan]
Abstract:
Natural electric power resources such as solar cells and wind power have been more widely used in recent years. However, the output from such power resources very often fluctuates, depending on various natural conditions. Consequently, we need technologies that can store electric energy in order to realize stable operation of power grids incorporating natural power resources. Pumped hydropower is one such technology, but it has become difficult to find suitable places to build new pumped hydropower stations.
Autors: Y. Ohki;
Appeared in: IEEE Electrical Insulation Magazine
Publication date: Jan 2017, volume: 33, issue:1, pages: 59 - 61
Publisher: IEEE
 
» Comments on “Compact Dual-Band Branch-Line Coupler With Dual Transmission Lines”
Abstract:
The synthesis and design method for the dual-band, dual transmission line branch-line coupler in [1] involves equivalent circuit transformations that are single-banded in nature and not suitable for the dual-band operations. The proposed equivalent dual transmission line transform has been applied only in the middle of the dual-band operation frequencies and its validity has not been confirmed at the two band frequencies. As the result, the proposed circuit equivalence can be quite poor and the coupler design in [1] based on it can be quite erroneous at the dual-band operation frequencies.
Autors: Myun-Joo Park;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Jan 2017, volume: 27, issue:1, pages: 103 - 104
Publisher: IEEE
 
» Compact Balanced Dual-Band Bandpass Filter Based on Modified Coupled-Embedded Resonators
Abstract:
A new compact balanced dual-band bandpass filter based on coupled-embedded resonators with modified ground plane is presented in this work. Common-mode is rejected within the two differential passbands by symmetrically introducing four coupled U-shaped defected ground structures below the resonators. Common-mode rejection is significantly improved when compared with the standard (solid ground plane) filter with similar geometry thanks to the introduction of four extra transmission zeros. Due to the symmetry, the differential mode is not significantly affected by the presence of the U-shaped resonators. Circuit-model data, full-wave simulations and measurements are provided to verify the benefits of the proposed dual-band filter.
Autors: Fulya Bagci;Armando Fernández-Prieto;Aintzane Lujambio;Jesús Martel;Joaquín Bernal;Francisco Medina;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Jan 2017, volume: 27, issue:1, pages: 31 - 33
Publisher: IEEE
 
» Compact Spectrometer Based on a Frosted Glass
Abstract:
We demonstrate a spectrometer based on multiple interference and scattering in an ordinary frosted glass featuring random structures. The probe signal disperses through the frosted glass generating wavelength-dependent speckle patterns, which are detected by a charge coupled device chip and used to reconstruct the input spectrum after calibration. We consider an underdetermined system of linear equations as a model for signal spectrum estimation. Smoothing regularization algorithm is designed for solving the system of equations. Experimental results show that the reconstruction range of the spectrometer at least includes the entire visible band and some part of the ultraviolet band. In comparison with conventional miniature spectrometers, the frosted glass spectrometer consequently has the merits of static measurement, low cost, small size, high throughput, and wide spectral range, which may find applications in a wide range of applications.
Autors: T. Yang;X. L. Huang;H. P. Ho;C. Xu;Y. Y. Zhu;M. D. Yi;X. H. Zhou;X. A. Li;W. Huang;
Appeared in: IEEE Photonics Technology Letters
Publication date: Jan 2017, volume: 29, issue:2, pages: 217 - 220
Publisher: IEEE
 
» Compact Tunable Balanced Bandpass Filter With Novel Multi-Mode Resonator
Abstract:
A novel multi-mode resonator is presented to design compact tunable balanced bandpass filters (BPFs). From the theoretical analysis, the common-mode (CM) resonant frequencies are different from that of the differential-mode (DM) response, so the CM suppression can be achieved without adding any extra lumped elements. For the DM response, the modal frequencies of odd and even modes can be adjusted simultaneously by varying the varactors. This helps to design the DM response with tunable passband center frequency. Moreover, the even-mode resonant frequency can be tuned independently, leading to controllable passband bandwidth of the DM. To verify the design method, a compact tunable balanced BPF is developed, fabricated and measured. Good agreement can be attained between the measurement and simulation.
Autors: Shi-Xuan Zhang;Zhi-Han Chen;Qing-Xin Chu;Senior Member;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Jan 2017, volume: 27, issue:1, pages: 43 - 45
Publisher: IEEE
 
» Compact Wideband and Low-Profile Antenna Mountable on Large Metallic Surfaces
Abstract:
This paper proposes a compact wideband and low-profile antenna mountable on large metallic surfaces. Six rows of coupled microstrip resonators with different lengths are printed on a Teflon block. The lengths of the microstrip resonators in different rows are gradually reduced along the endfire direction. The first four rows of resonators provide four resonances at different frequencies for bandwidth enhancement. The last two rows of resonators are used as two directors to suppress sidelobe levels at high frequencies. A trapezoidal launcher is applied to serve as a reflector and provide one resonance at the lowest frequency. A trapezoid-shaped capacitive-feed strip is utilized and also printed on the Teflon block to globally optimize the wideband impedance matching. The proposed antenna covers a relative bandwidth of 109% for VSWR < 2 with a height of and a volume of only ( being the free-space wavelength at the lowest operating frequency). Within the operating band, the realized gain is better than 6.5 dBi and the radiation efficiency is higher than 95%.
Autors: Shuai Zhang;Gert Frølund Pedersen;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Jan 2017, volume: 65, issue:1, pages: 6 - 16
Publisher: IEEE
 
» Comparing Theoretical and Experimental Results in Gen2 RFID Throughput
Abstract:
Radio frequency identification (RFID) technology, based on wireless communication between a reader and tags, is the most popular technology for indoor item identification and tracking. Among competing RFID technologies, Gen2 has emerged as the most popular one, due to the best price/performance ratio. In order to communicate with multiple tags, Gen2 RFID systems use dynamic frame slotted ALOHA (DFSA) as a medium access control (MAC) mechanism. To maximize DFSA throughput simple calculations show that the number of tags should equal the DFSA frame size. However, the number of tags in an environment is usually unknown and has to be estimated. So far, significant effort has been invested in estimating the correct number of tags. However, to the best of our knowledge, no one has explored the estimator performance in a real RFID measuring scenario. In this paper, we evaluate the throughput of a real RFID system by using the Software Defined Radio (SDR) technology. Our results show that phenomena related to radio waves propagation and reception have a significantly bigger influence on Gen2 RFID throughput than traditional approaches take into account.
Autors: Petar Šolić;Josip Maras;Joško Radić;Zoran Blažević;
Appeared in: IEEE Transactions on Automation Science and Engineering
Publication date: Jan 2017, volume: 14, issue:1, pages: 349 - 357
Publisher: IEEE
 
» Comparison of SOI Versus Bulk FinFET Technologies for 6T-SRAM Voltage Scaling at the 7-/8-nm Node
Abstract:
The electrostatic benefit of using a silicon-on-insulator (SOI) wafer substrate versus a bulk-silicon wafer substrate with optimized supersteep retrograde (SSR) doping for a low-power 7-/8-nm FinFET technology is investigated via 3-D device simulations and a fitted compact model to estimate the manufacturing yield of six-transistor SRAM cells. SOI FinFET technology is projected to provide only slight improvement in performance and minimum cell operating voltage as compared with SSR FinFET technology.
Autors: Xi Zhang;Daniel Connelly;Hideki Takeuchi;Marek Hytha;Robert J. Mears;Tsu-Jae King Liu;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Jan 2017, volume: 64, issue:1, pages: 329 - 332
Publisher: IEEE
 
» Comparison of TFETs and CMOS Using Optimal Design Points for Power–Speed Tradeoffs
Abstract:
Tunnel transistors are one of the most attractive steep subthreshold slope devices currently being investigated as a means of overcoming the power density and energy inefficiency limitations of CMOS technology. In this paper, the evaluation and the comparison of the performance of distinct fan-in logic gates, using a set of widely accepted power–speed metrics, are addressed for five projected tunnel transistor (TFET) technologies and four mosfet and FinFET transistors. The impact of logic depth, switching activity, and minimum supply voltage has been also included in our analysis. Provided results suggest that benefits in terms of a certain metric, in which a higher weight is placed on power or delay, are strongly determined by the selected device. Particularly, the suitability of two of the explored TFET technologies to improve CMOS performance for different metrics is pointed out. A circuit level benchmark is evaluated to validate our analysis.
Autors: Juan Núñez;María J. Avedillo;
Appeared in: IEEE Transactions on Nanotechnology
Publication date: Jan 2017, volume: 16, issue:1, pages: 83 - 89
Publisher: IEEE
 
» Comparison of Two Magnetic Saturation Models of Induction Machines and Experimental Validation
Abstract:
This paper develops a systematic comparison of two nonlinear models of induction machines in magnetic saturation using stator and rotor currents as state variables. One of the models accounts for dynamic cross-saturation effects, whereas the other neglects them. Analytic derivations yield an explicit description of the difference between the models showing that differences can only be observed through transient responses in the saturated region. To refine the comparison, and exclude conditions in the linear magnetic region, the dynamics of self-excited induction generators around stable operating points is analyzed. Unexpected and interesting features of the models are revealed through their linearization in the reference frame aligned with the stator voltage vector, followed by computation of the transfer functions from perturbations to state deviations. The analysis predicts a slower exponential convergence of the simplified model compared to the full model, despite very close responses in the initial period. The comparison is validated via thorough experiments and simulations. This paper provides experimental evidence of the higher accuracy of the full model for transients deep into the saturated region. For realistic operating conditions, the difference is found to be rather small, and often comparable to the steady-state error caused by inaccuracies in the parameters.
Autors: Oleh Kiselychnyk;Marc Bodson;Jihong Wang;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Jan 2017, volume: 64, issue:1, pages: 81 - 90
Publisher: IEEE
 
» Complex Correntropy: Probabilistic Interpretation and Application to Complex-Valued Data
Abstract:
Recent studies have demonstrated that correntropy is an efficient tool for analyzing higher order statistical moments in non-Gaussian noise environments. Although correntropy has been used with complex data, no theoretical study was pursued to elucidate its properties, nor how to best use it for optimization. By using a probabilistic interpretation, this work presents a novel similarity measure between two complex random variables, which is defined as complex correntropy. A new recursive solution for the maximum complex correntropy criterion is introduced based on a fixed-point solution. This technique is applied to a system identification, and the results demonstrate prominent advantages when compared against three other algorithms: the complex least mean square, complex recursive least squares, and least absolute deviation. By the aforementioned probabilistic interpretation, correntropy can now be applied to solve several problems involving complex data in a more straightforward way.
Autors: João P. F. Guimarães;Aluisio I. R. Fontes;Joilson B. A. Rego;Allan de M. Martins;José C. Príncipe;
Appeared in: IEEE Signal Processing Letters
Publication date: Jan 2017, volume: 24, issue:1, pages: 42 - 45
Publisher: IEEE
 
» Complex-Frequency Shifted PMLs for Maxwell’s Equations With Hyperbolic Divergence Cleaning and Their Application in Particle-in-Cell Codes
Abstract:
The simulation of unbounded domains inevitably requires an artificial truncation of the computational domain and spurious reflections resulting from this procedure are a common problem. In this paper, a perfectly matched layer formulation for Maxwell’s equations in purely hyperbolic form is presented. The model is applied to standard wave attenuation problems and particle-in-cell simulations of electron beam devices.
Autors: Stephen M. Copplestone;Philip Ortwein;Claus-Dieter Munz;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Jan 2017, volume: 45, issue:1, pages: 2 - 14
Publisher: IEEE
 
» Compound Radar Approach for Breast Imaging
Abstract:
Multistatic radar apertures record scattering at a number of receivers when the target is illuminated by a single transmitter, providing more scattering information than its monostatic counterpart per transmission angle. This paper considers the well-known problem of detecting tumor targets within breast phantoms using multistatic radar. To accurately image potentially cancerous targets size within the breast, a significant number of multistatic channels are required in order to adequately calibrate-out unwanted skin reflections, increase the immunity to clutter, and increase the dynamic range of a breast radar imaging system. However, increasing the density of antennas within a physical array is inevitably limited by the geometry of the antenna elements designed to operate with biological tissues at microwave frequencies. A novel compound imaging approach is presented to overcome these physical constraints and improve the imaging capabilities of a multistatic radar imaging modality for breast scanning applications. The number of transmit-receive (TX-RX) paths available for imaging are increased by performing a number of breast scans with varying array positions. A skin calibration method is presented to reduce the influence of skin reflections from each channel. Calibrated signals are applied to receive a beamforming method, compounding the data from each scan to produce a microwave radar breast profile. The proposed imaging method is evaluated with experimental data obtained from constructed phantoms of varying complexity, skin contour asymmetries, and challenging tumor positions and sizes. For each imaging scenario outlined in this study, the proposed compound imaging technique improves skin calibration, clearly detects small targets, and substantially reduces the level of undesirable clutter within the profile.
Autors: Dallan Byrne;Mantalena Sarafianou;Ian J. Craddock;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Jan 2017, volume: 64, issue:1, pages: 40 - 51
Publisher: IEEE
 
» Comprehensive Protection Strategy for an Islanded Microgrid Using Intelligent Relays
Abstract:
In this paper, a comprehensive protection strategy is proposed for insuring dependable and secure operation of an islanded microgrid system. This is implemented using microprocessor-based relays to prevent unnecessary loss of critical loads and distributed generators (DGs). Several improvements are proposed to clear the way for plug-and-play of DGs. Furthermore, recommendations are presented to tackle the elusive high-impedance fault problem, commonly encountered in distribution systems. An optimal directional overcurrent bus protection is also presented. Several case studies and analyses are carried out to demonstrate the proposed protection strategy. Results from simulation using MATLAB/Simulink are also shown.
Autors: Kexing Lai;Mahesh S. Illindala;Mohammed A. Haj-ahmed;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Jan 2017, volume: 53, issue:1, pages: 47 - 55
Publisher: IEEE
 
» Compressed Sensing for Efficient Encoding of Dense 3D Meshes Using Model-Based Bayesian Learning
Abstract:
With the growing demand for easy and reliable generation of 3D models representing real-world or synthetic objects, new schemes for acquisition, storage, and transmission of 3D meshes are required. In principle, 3D meshes consist of vertex positions and vertex connectivity. Vertex position encoders are much more resource demanding than connectivity encoders, stressing the need for novel geometry compression schemes. The design of an accurate and efficient geometry compression system can be achieved by increasing the compression ratio without affecting the visual quality of the object and minimizing the computational complexity. In this paper, we present novel compression/reconstruction schemes that enable aggressive compression ratios, without significantly reducing the visual quality. The encoding is performed by simply executing additions/subtractions. The benefits of the proposed method become more apparent as the density of the meshes increases, while it provides a flexible framework to trade efficiency for reconstruction quality. We derive a novel Bayesian learning algorithm that models the most significant graph Fourier transform coefficients of each submesh, as a multivariate Gaussian distribution. Then we evaluate iteratively the distribution parameters using the expectation-maximization approach. To improve the performance of the proposed approach in highly under determined problems, we exploit the local smoothness of the partitioned surfaces. Extensive evaluation studies, carried out using a large collection of different 3D models, show that the proposed schemes, as compared to the state-of-the-art approaches, achieve competitive compression ratios, offering at the same time significantly lower encoding complexity.
Autors: Aris S. Lalos;Iason Nikolas;Evangelos Vlachos;Konstantinos Moustakas;
Appeared in: IEEE Transactions on Multimedia
Publication date: Jan 2017, volume: 19, issue:1, pages: 41 - 53
Publisher: IEEE
 
» Compressive Privacy: From Information/Estimation Theory to Machine Learning [Lecture Notes]
Abstract:
Most of our daily activities are now moving online in the big data era, with more than 25 billion devices already connected to the Internet, to possibly over a trillion in a decade. However, big data also bears a connotation of “big brother” when personal information (such as sales transactions) is being ubiquitously collected, stored, and circulated around the Internet, often without the data owner's knowledge. Consequently, a new paradigm known as online privacy or Internet privacy is becoming a major concern regarding the privacy of personal and sensitive data.
Autors: S.Y. Kung;
Appeared in: IEEE Signal Processing Magazine
Publication date: Jan 2017, volume: 34, issue:1, pages: 94 - 112
Publisher: IEEE
 
» Compressive Sensing-Based Beamforming for Millimeter-Wave OFDM Systems
Abstract:
In this paper, we address codebook-based beamforming for multi-antenna orthogonal frequency division multiplexing (OFDM) systems operating in 60-GHz millimeter-wave band. Given a pre-specified codebook, the task of the beamforming process is to identify the best transmit and receive beam vectors to maximize the spectral efficiency. By properly modeling the multipath structure in 60-GHz channels, we transform the above task into the estimation of several sparse signal vectors. Furthermore, we tailor compressive sensing (CS) technology to efficiently estimate such sparse signals, wherein the CS measurement matrix is specifically designed by minimizing the inner products between different columns of the CS effective dictionary. As a result, CS-based iterative and non-iterative beamforming schemes are proposed. Due to the ability to judiciously exploit multipath sparsity inherent in 60-GHz channels, the proposed schemes significantly outperform the existing counterparts in terms of training overhead and success probability, which is confirmed by theoretical analysis and extensive simulations.
Autors: Xiantao Cheng;Mengyao Wang;Shaoqian Li;
Appeared in: IEEE Transactions on Communications
Publication date: Jan 2017, volume: 65, issue:1, pages: 371 - 386
Publisher: IEEE
 
» Compressive Sensing-Based Pilot Design for Sparse Channel Estimation in OFDM Systems
Abstract:
We consider the deterministic pilot design problem for sparse channel estimation in an Orthogonal Frequency Division Multiplexing (OFDM) system. Our design is based on minimizing the coherence measure of the Fourier submatrix associated with the pilot subcarriers. This is done by optimizing over both pilot locations and pilot powers. As finding such global minimizer is a combinatorial problem, we resort to a greedy pilot allocation method. The resulting method achieves a suboptimal solution in a sequential manner and with reasonable computational complexity. Simulation results demonstrate that the proposed scheme performs similar to the existing methods with significantly lower computational complexity.
Autors: Roozbeh Mohammadian;Arash Amini;Babak Hossein Khalaj;
Appeared in: IEEE Communications Letters
Publication date: Jan 2017, volume: 21, issue:1, pages: 4 - 7
Publisher: IEEE
 
» Compressive Video Sensing: Algorithms, architectures, and applications
Abstract:
The design of conventional sensors is based primarily on the Shannon?Nyquist sampling theorem, which states that a signal of bandwidth W Hz is fully determined by its discrete time samples provided the sampling rate exceeds 2 W samples per second. For discrete time signals, the Shannon?Nyquist theorem has a very simple interpretation: the number of data samples must be at least as large as the dimensionality of the signal being sampled and recovered. This important result enables signal processing in the discrete time domain without any loss of information. However, in an increasing number of applications, the Shannon-Nyquist sampling theorem dictates an unnecessary and often prohibitively high sampling rate (see “What Is the Nyquist Rate of a Video Signal?”). As a motivating example, the high resolution of the image sensor hardware in modern cameras reflects the large amount of data sensed to capture an image. A 10-megapixel camera, in effect, takes 10 million measurements of the scene. Yet, almost immediately after acquisition, redundancies in the image are exploited to compress the acquired data significantly, often at compression ratios of 100:1 for visualization and even higher for detection and classification tasks. This example suggests immense wastage in the overall design of conventional cameras.
Autors: Richard G. Baraniuk;Thomas Goldstein;Aswin C. Sankaranarayanan;Christoph Studer;Ashok Veeraraghavan;Michael B. Wakin;
Appeared in: IEEE Signal Processing Magazine
Publication date: Jan 2017, volume: 34, issue:1, pages: 52 - 66
Publisher: IEEE
 
» Computationally Efficient Weighted Binary Decision Codes for Gas Identification With Array of Gas Sensors
Abstract:
Motivated by biological olfactory coding principles, rank-code-based classifiers have recently been proposed to facilitate integration of hardware-friendly gas identification platforms with an array of gas sensors. These classifiers operate on a simple principle of generating rank-codes by ranking the gas sensors’ features instead of treating them as a multi-dimensional vector as in computation-intensive state-of-the-art gas classifiers. However, the performance of the rank-code-based classifiers is limited when distinguishing information about all the target gases is not found in the ranks of the gas sensors’ features, but in their values. In this paper, we introduce a computationally efficient alternative solution to overcome this limitation. In this solution, an original multi-gas classification problem is decomposed into pairwise classifiers, and the gas is then predicted with the weighted binary decision codes in each of these classifiers, where each element of the code is generated by exploiting features individually. The weighted binary decision codes are formed by first using the nearest centroid approach, which exploits the mean value of each gas sensor’s feature to generate binary decision codes, and then, a simple approach is used to assign a weight to each element of the code, depending upon its capability to discriminate the gases in each pairwise classifier. The added advantage of this classification approach is that two computationally efficient metrics are introduced to access the classifiers’ applicability to the given data set and certainty about the prediction of any test sample. A classification performance of 97.87% is achieved with this approach on an extensive data set of ten gases experimentally obtained with Figaro series gas sensors, and this is increased to 100% by rejecting 3.37% of samples for which certai- ty about their predictions is below a 25% confidence level.
Autors: Muhammad Hassan;Muhammad Umar;Amine Bermak;
Appeared in: IEEE Sensors Journal
Publication date: Jan 2017, volume: 17, issue:2, pages: 487 - 497
Publisher: IEEE
 
» Computer's 50th Anniversary
Abstract:
With maturity comes reflection and enlightenment. In this golden anniversary year, Computer celebrates not only its impressive past, but also the promise of its future.
Autors: Sumi Helal;
Appeared in: Computer
Publication date: Jan 2017, volume: 50, issue:1, pages: 14 - 18
Publisher: IEEE
 
» Computer, Drive My Car!
Abstract:
Autonomous vehicles will lead to a safer, cleaner world.
Autors: Shaoshan Liu;James Peng;Jean-Luc Gaudiot;
Appeared in: Computer
Publication date: Jan 2017, volume: 50, issue:1, pages: 8 - 8
Publisher: IEEE
 
» Computer, January 1967 and 1992
Abstract:
A summary of articles published in Computer 50 and 25 years ago.
Autors: Erich Neuhold;
Appeared in: Computer
Publication date: Jan 2017, volume: 50, issue:1, pages: 10 - 11
Publisher: IEEE
 
» Computing a Guaranteed Approximation of the Zone Explored by a Robot
Abstract:
This technical note deals with the guaranteed characterization of the part of the space that has been explored by a robot. The main difficulty of the problem is to take into account the uncertainty associated with the trajectory and the fact that the dimension of the visible space at time may be smaller than that of the workspace. An example involving an experiment made with an actual underwater robot is presented in order to illustrate the efficiency of the approach.
Autors: Benoît Desrochers;Luc Jaulin;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Jan 2017, volume: 62, issue:1, pages: 425 - 430
Publisher: IEEE
 
» Computing Maximum Cardinality Matchings in Parallel on Bipartite Graphs via Tree-Grafting
Abstract:
It is difficult to obtain high performance when computing matchings on parallel processors because matching algorithms explicitly or implicitly search for paths in the graph, and when these paths become long, there is little concurrency. In spite of this limitation, we present a new algorithm and its shared-memory parallelization that achieves good performance and scalability in computing maximum cardinality matchings in bipartite graphs. Our algorithm searches for augmenting paths via specialized breadth-first searches (BFS) from multiple source vertices, hence creating more parallelism than single source algorithms. Algorithms that employ multiple-source searches cannot discard a search tree once no augmenting path is discovered from the tree, unlike algorithms that rely on single-source searches. We describe a novel tree-grafting method that eliminates most of the redundant edge traversals resulting from this property of multiple-source searches. We also employ the recent direction-optimizing BFS algorithm as a subroutine to discover augmenting paths faster. Our algorithm compares favorably with the current best algorithms in terms of the number of edges traversed, the average augmenting path length, and the number of iterations. We provide a proof of correctness for our algorithm. Our NUMA-aware implementation is scalable to 80 threads of an Intel multiprocessor and to 240 threads on an Intel Knights Corner coprocessor. On average, our parallel algorithm runs an order of magnitude faster than the fastest algorithms available. The performance improvement is more significant on graphs with small matching number.
Autors: Ariful Azad;Aydın Buluç;Alex Pothen;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Jan 2017, volume: 28, issue:1, pages: 44 - 59
Publisher: IEEE
 
» Computing Semantic Similarity of Concepts in Knowledge Graphs
Abstract:
This paper presents a method for measuring the semantic similarity between concepts in Knowledge Graphs (KGs) such as WordNet and DBpedia. Previous work on semantic similarity methods have focused on either the structure of the semantic network between concepts (e.g., path length and depth), or only on the Information Content (IC) of concepts. We propose a semantic similarity method, namely wpath, to combine these two approaches, using IC to weight the shortest path length between concepts. Conventional corpus-based IC is computed from the distributions of concepts over textual corpus, which is required to prepare a domain corpus containing annotated concepts and has high computational cost. As instances are already extracted from textual corpus and annotated by concepts in KGs, graph-based IC is proposed to compute IC based on the distributions of concepts over instances. Through experiments performed on well known word similarity datasets, we show that the wpath semantic similarity method has produced a statistically significant improvement over other semantic similarity methods. Moreover, in a real category classification evaluation, the wpath method has shown the best performance in terms of accuracy and F score.
Autors: Ganggao Zhu;Carlos A. Iglesias;
Appeared in: IEEE Transactions on Knowledge and Data Engineering
Publication date: Jan 2017, volume: 29, issue:1, pages: 72 - 85
Publisher: IEEE
 
» ConceFT for Time-Varying Heart Rate Variability Analysis as a Measure of Noxious Stimulation During General Anesthesia
Abstract:
Objective: Heart rate variability (HRV) offers a noninvasive way to peek into the physiological status of the human body. When this physiological status is dynamic, traditional HRV indices calculated from power spectrum do not resolve the dynamic situation due to the issue of nonstationarity. Clinical anesthesia is a typically dynamic situation that calls for time-varying HRV analysis. Concentration of frequency and time (ConceFT) is a nonlinear time–frequency (TF) analysis generalizing the multitaper technique and the synchrosqueezing transform. The result is a sharp TF representation capturing the dynamics inside HRV. Companion indices of the commonly applied HRV indices, including time-varying low-frequency power (tvLF), time-varying high-frequency power, and time-varying low-high ratio, are considered as measures of noxious stimulation. Methods: To evaluate the feasibility of the proposed indices, we apply these indices to study two different types of noxious stimulation, the endotracheal intubation and surgical skin incision, under general anesthesia. The performance was compared with traditional HRV indices, the heart rate reading, and indices from electroencephalography. Results: The results indicate that the tvLF index performs best and outperforms not only the traditional HRV index, but also the commonly used heart rate reading. Conclusion: With the help of ConceFT, the proposed HRV indices are potential to provide a better quantification of the dynamic change of the autonomic nerve system. Significance: Our proposed scheme of time-varying HRV analysis could contribute to the clinical assessment of analgesia under general anesthesia.
Autors: Yu-Ting Lin;Hau-Tieng Wu;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Jan 2017, volume: 64, issue:1, pages: 145 - 154
Publisher: IEEE
 
» Condition Assessment of Electrical Apparatus With EMI Diagnostics
Abstract:
This paper describes the theory, development history, and application of electromagnetic interference diagnostics for the condition assessment of high-voltage apparatus such as motors, generators, transformers, switchgear, and bus. Data are collected while equipment remains in service. Examples of common problems identified at power facilities, upstream off shore production rigs as well as downstream, plastics, chemical, and central utility facilities are provided. How data are collected, analyzed, and presented is discussed.
Autors: James E. Timperley;José M. Vallejo;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Jan 2017, volume: 53, issue:1, pages: 693 - 699
Publisher: IEEE
 
» Conductivity Invariance Phenomenon of Eddy Current NDT: Investigation, Verification, and Application
Abstract:
Both the electrical conductivity and the magnetic permeability of a measured sample have significant impact on the detected signal in eddy current nondestructive testing. Therefore, the problem of obtaining accurate measurement for the electrical conductivity or magnetic permeability has been of great interest to design and manufacturing engineers. In this paper, the conductivity invariance phenomenon (CIP) is investigated and utilized to detect the magnetic permeability of metals. First, the CIP is introduced and its sensitivity factors are investigated using a finite-element method. An experimental platform is set up based on which the CIP is verified. Finally, a magnetic permeability measurement device is proposed, which separates the coupling impact of the sample’s electrical conductivity and magnetic permeability. The work reported in this paper provides an effective approach to accurately estimate the magnetic permeability of metals without the influence of its conductivity.
Autors: Yating Yu;Yu Zou;Mohamed Al Hosani;Guiyun Tian;
Appeared in: IEEE Transactions on Magnetics
Publication date: Jan 2017, volume: 53, issue:1, pages: 1 - 7
Publisher: IEEE
 
» Cone Beam X-ray Luminescence Computed Tomography Based on Bayesian Method
Abstract:
X-ray luminescence computed tomography (XLCT), which aims to achieve molecular and functional imaging by X-rays, has recently been proposed as a new imaging modality. Combining the principles of X-ray excitation of luminescence-based probes and optical signal detection, XLCT naturally fuses functional and anatomical images and provides complementary information for a wide range of applications in biomedical research. In order to improve the data acquisition efficiency of previously developed narrow-beam XLCT, a cone beam XLCT (CB-XLCT) mode is adopted here to take advantage of the useful geometric features of cone beam excitation. Practically, a major hurdle in using cone beam X-ray for XLCT is that the inverse problem here is seriously ill-conditioned, hindering us to achieve good image quality. In this paper, we propose a novel Bayesian method to tackle the bottleneck in CB-XLCT reconstruction. The method utilizes a local regularization strategy based on Gaussian Markov random field to mitigate the ill-conditioness of CB-XLCT. An alternating optimization scheme is then used to automatically calculate all the unknown hyperparameters while an iterative coordinate descent algorithm is adopted to reconstruct the image with a voxel-based closed-form solution. Results of numerical simulations and mouse experiments show that the self-adaptive Bayesian method significantly improves the CB-XLCT image quality as compared with conventional methods.
Autors: Guanglei Zhang;Fei Liu;Jie Liu;Jianwen Luo;Yaoqin Xie;Jing Bai;Lei Xing;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Jan 2017, volume: 36, issue:1, pages: 225 - 235
Publisher: IEEE
 
» Conference Report/IEEE OnlineGreenComm 2016
Abstract:
Autors: Josip Lorincz;Michela Meo;Emad Alsusa;Marco Ruffini;Paolo Monti;Andres Garcia Saavedra;Chin Keong Ho;
Appeared in: IEEE Communications Magazine
Publication date: Jan 2017, volume: 55, issue:1, pages: 6 - 7
Publisher: IEEE
 
» Configurable Microwave Filter for Signal Processing Based on Arrays of Bistable Magnetic Nanowires
Abstract:
Using arrays of bistable magnetic nanowires, we show that their microwave absorption properties can be reversibly configured using low magnetic field cycling by virtue of the double ferromagnetic resonance absorption spectra. These characteristics lead to a single bifunction microwave filter that can be configured to work as a bandstop or a bandpass filter, making these materials very attractive for compact multifunction planar microwave devices. The bifunction microwave properties of these systems are successfully predicted using a mean field model for their magnetic configuration-dependent effective permeability.
Autors: Rossana Ramírez-Villegas;Isabelle Huynen;Luc Piraux;Armando Encinas;Joaquin De La Torre Medina;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Jan 2017, volume: 65, issue:1, pages: 72 - 77
Publisher: IEEE
 
» Consequences of Landsat Image Strata Classification Errors on Bias and Variance of Inventory Estimates: A Forest Inventory Case Study
Abstract:
Use of remotely sensed (e.g., Landsat) imagery for developing sampling frame strata for large-scale inventories of natural resources has potential for increasing sampling efficiency and lowering cost by reducing required sample sizes. Sampling frame errors are inherent with the use of this technology, either from user misclassification or due to flawed technology. Knowledge of these sampling frame errors is important, as they inflate the variance of inventory estimates, particularly poststratified estimates. Forest inventory estimates from the Mississippi Institute for Forest Inventory (MIFI) were utilized to study the extent to which Geographic Information System classification errors (sampling frame errors) affect forest volume and area mean and variance estimates. MIFI's high sampling intensity provided a unique opportunity to quantify the magnitude that different levels of misclassification ultimately have on mean and variance estimates. A variance calculator was developed to assess the impact of various levels of misclassification on least and most variable summary estimates of cubic meter volume percent and total area. The standard error estimates for mean and total volume decreased when plots were reallocated to their correct strata. The increased efficiency obtained from correcting misclassifications illustrates that the loss in precision due to misclassifying inventory strata is consequential. Knowledge and correction of these errors provides a natural-resource-based professional or investor using land classification/inventory data the best minimum risk information possible. A complete set of variance estimators for poststratified means and total area estimates with sampling frame errors are presented and compared to estimators without sampling frame errors.
Autors: Michael K. Crosby;Thomas G. Matney;Emily B. Schultz;David L. Evans;Donald L. Grebner;H. Alexis Londo;John C. Rodgers;Curtis A. Collins;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Jan 2017, volume: 10, issue:1, pages: 243 - 251
Publisher: IEEE
 
» Consideration of the Effect of Barrier Height on the Variation of Specific Contact Resistance With Temperature
Abstract:
Temperature variation during semiconductor device operation can be significant and how this affects contact resistance is investigated. This paper reports improvements to analytical modeling for determining specific contact resistance (SCR) by including the effect of temperature. A technique for extracting the value of SCR using technology computer-aided design (TCAD) modeling is also demonstrated. SCR results obtained for analytical and TCAD models for metal-to-silicon contacts are compared and this shows the significance of temperature in the analytical model. Small changes in electron affinity and, hence, barrier height due to changes in temperature must be considered in order to obtain reliable analytical expressions for SCR.
Autors: Hiep N. Tran;Tuan A. Bui;Aaron M. Collins;Anthony S. Holland;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Jan 2017, volume: 64, issue:1, pages: 325 - 328
Publisher: IEEE
 
» Consistency of the Two Component Composite Modeling Framework for NBTI in Large and Small Area p-MOSFETs
Abstract:
Consistency of the recently proposed deterministic composite modeling framework for Negative Bias Temperature Instability (NBTI) in large area devices is verified for stochastic NBTI in small area devices. The framework has two independent and uncoupled components, interface trap generation (), and hole trapping in pre-existing defects (). The time evolution of mean threshold voltage shift (), from multiple ultra-fast measurements in small area devices under diverse stress and recovery conditions, is predicted by the deterministic composite framework. It is shown that although the physical mechanism of NBTI remains the same as the device area is scaled, there can be significant differences in the relative and contribution to between large and small area devices, which can alter the overall model parameters. A stochastic simulation framework, fully consistent with the deterministic framework, is developed, which is shown to predict experimentally measured mean time evolution of in small area devices.
Autors: Ankush Chaudhary;Beryl Fernandez;Narendra Parihar;Souvik Mahapatra;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Jan 2017, volume: 64, issue:1, pages: 256 - 263
Publisher: IEEE
 
» Constant Envelope Precoding by Interference Exploitation in Phase Shift Keying-Modulated Multiuser Transmission
Abstract:
We introduce a new approach to constant-envelope precoding (CEP) based on an interference-driven optimization region for generic phase-shift-keying modulations in the multi-user (MU) multiple-input-multiple-output downlink. While conventional precoding approaches aim to minimize the multi-user interference (MUI) with a total sum-power constraint at the transmitter, in the proposed scheme we consider MUI as a source of additional energy to increase the signal-to-interference-and-noise-ratio at the receiver. In our studies, we focus on two different CEP approaches: a first technique, where the power at each antenna is fixed to a specific value, and a two-step approach, where we first relax the power constraints to be lower than a defined parameter and then enforce CEP transmission. The algorithms are studied in terms of computational costs, with a detailed comparison between the proposed approach and the classical interference suppression schemes from the literature. Moreover, we analytically derive a robust optimization region to counteract the effects of channel-state estimation errors. The presented schemes are evaluated in terms of achievable symbol error rate in a perfect and imperfect channel-state information scenario for different modulation orders. Our results show that the proposed techniques further extend the benefits of classical CEP by judiciously relaxing the optimization region.
Autors: Pierluigi Vito Amadori;Christos Masouros;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Jan 2017, volume: 16, issue:1, pages: 538 - 550
Publisher: IEEE
 
» Constellation Collaborated Nonlinear Orthogonal Space–Time Block Codes With Fast Maximum-Likelihood Detection
Abstract:
In this paper, constellation collaborated nonlinear orthogonal space–time block codes (OSTBCs) for wireless communication systems are considered. Using the recently developed unique factorization of signals, several uniquely factorable constellation pairs (UFCPs) generated from cross quadrature amplitude modulation (QAM) constellations are chosen for transmission through all the transmitter antennas, with one random symbol acting as a coordinator to control all the symbols embedded in each coding matrix. The coding gains of collaborated orthogonal codes are calculated, and some optimal constellation pairs with maximum coding gains are presented, including orthogonal codes with different antennas and UFCPs with different groups. Despite the fact that the proposed code is nonlinear, a fast maximum likelihood (ML) decoding algorithm is developed, and its complexity is analyzed in detail. By comparing the decoding complexity of conventional Alamouti code, the ML algorithm, and the fast ML decoding algorithm of collaborative Alamouti code, it can be observed that the complexity of fast ML algorithm is still linear in terms of the square root of the cardinality of the cross QAM constellations with no performance loss. Computer simulations are performed to verify the performance of collaborative OSTBCs and the fast ML Algorithm under different conditions, and the results demonstrate that the average error rate of the collaborative nonlinear orthogonal codes outperforms that of the conventional OSTBCs.
Autors: Yi-Jun Zhu;Wen-Ya Wang;Jian-Kang Zhang;Yan-Yu Zhang;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jan 2017, volume: 66, issue:1, pages: 513 - 528
Publisher: IEEE
 
» Construction of a Generalized DFT Codebook Using Channel-Adaptive Parameters
Abstract:
Discrete Fourier transform (DFT)-based codebooks are known to work efficiently for spatially correlated channels produced by uniform linear arrays. Although the long-term codebooks are selected to suit to channel correlation characteristics, such selections may not be optimal for the given channel of the target user equipment (UE), due to the specific structure and constraints of the codebook in use. In this letter, we propose a generalized DFT-based codebook structure employing variable parameters to provide enhanced resolution of codevectors and adjustable spacing among them. The proposal includes the Release 10 codebook of LTE-advanced as a special case, with added flexibility via parameter configurations. When tested over the 3GPP spatial channel model, the new codebook exhibits significant gains over existing ones, outperforming the LTE-advanced codebook in entire UE locations within the sector.
Autors: Junyeub Suh;Changhyeon Kim;Wonjin Sung;Jaewoo So;Seo Weon Heo;
Appeared in: IEEE Communications Letters
Publication date: Jan 2017, volume: 21, issue:1, pages: 196 - 199
Publisher: IEEE
 
» Construction of Synergistic Potential Functions on SO(3) With Application to Velocity-Free Hybrid Attitude Stabilization
Abstract:
We propose a systematic and comprehensive procedure for the construction of synergistic potential functions, which are instrumental in hybrid control design on . A new map, via angular warping on , is introduced to generate a central family of potential functions allowing an explicit determination of the critical points and the synergistic gap. Some optimization results on the synergistic gap are also provided. The proposed synergistic potential functions are used for the design of a global velocity-free hybrid attitude stabilization scheme relying solely on inertial vector measurements.
Autors: Soulaimane Berkane;Abdelhamid Tayebi;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Jan 2017, volume: 62, issue:1, pages: 495 - 501
Publisher: IEEE
 
» Contactless Characterization of Coplanar Stripline Discontinuities by RCS Measurement
Abstract:
This paper presents a contactless approach to characterize coplanar stripline discontinuities based on a radar cross section measurement method. With this approach, the values of the equivalent lumped element models are determined for two discontinuities often encountered in practice: open circuit and short circuit. The discontinuities are incorporated into two different very simple resonators. But contrarily to what is usually done, here the resonators are considered as radar resonant targets and are illuminated by a plane wave. The incremental electrical length due to the discontinuities causes a shift of the resonance frequency, which is used for the extraction of the parameters. The values obtained from full-wave simulations are compared to measurements and to other data available from previous studies.
Autors: Olivier Rance;Romain Siragusa;Pierre Lemaître-Auger;Etienne Perret;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Jan 2017, volume: 65, issue:1, pages: 251 - 257
Publisher: IEEE
 
» Content Addressable Memory—Early Predict and Terminate Precharge of Match-Line
Abstract:
A novel content addressable memory (CAM) architecture with a simple but very effective precharge controller is presented. CAM is a hardware search mechanism that precharges all its match lines (MLs) during the precharge phase, and a search is performed during the evaluate phase. With unique words stored in a CAM, all the MLs except the one, which matches with the search word have to be discharged for every search cycle. The MLs that mismatch will anyway drain the charge during the evaluation phase, here, those mismatching MLs are predicted early during the precharge phase to terminate the full precharging of such lines. This promises CAM with reduced power as well as improved search speed.
Autors: Mohammed Zackriya V;Harish M. Kittur;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Jan 2017, volume: 25, issue:1, pages: 385 - 387
Publisher: IEEE
 
» Content placement with maximum number of end-to-content paths in K-node (edge) content connected optical datacenter networks
Abstract:
To design survival datacenter networks, the concept of content connectivity, which is defined as the reachability of content from any point of a network after disaster failures, was recently proposed. To quantitatively measure content connectivity, we propose a novel concept of k-node (edge) content connectivity and apply it to optical datacenter networks. Furthermore, a novel disaster-resilient k-node (edge) content connected optical datacenter network (KC-ODN) is proposed in this paper. Design of the KC-ODN is divided into two sub-problems: content placement and independent end-to-content paths calculation. We consider flexible content placement (FCP), in which the content is replicated and maintained in multiple datacenters, rather than fixed content placement (FICP), in which the content is replicated and maintained in only one fixed datacenter, to realize KC-ODN. The integer linear program (ILP) model and heuristic algorithms are developed to achieve KC-ODN. Numerical results show that the method of FCP has lower wavelength consumption than the method of FICP. It is easier to realize high-level k-node (edge) content connectivity in a network with higher connectivity. Compared with the ILP method, heuristic algorithms are more scalable for large-scale optical datacenter networks.
Autors: Xin Li;Shan Yin;Xinbo Wang;Yu Zhou;Yongli Zhao;Shanguo Huang;Jie Zhang;
Appeared in: IEEE/OSA Journal of Optical Communications and Networking
Publication date: Jan 2017, volume: 9, issue:1, pages: 53 - 66
Publisher: IEEE
 
» Contrast Enhanced Subsurface Fingerprint Detection Using High-Speed Optical Coherence Tomography
Abstract:
Spectral-domain optical coherence tomography (SD-OCT) has been demonstrated to be a viable tool in forensic science for fingerprint detection, yet it still suffers from certain practical issues, e.g., the limited scanning speed and low image contrast. In this letter, we report a high-speed SD-OCT together with an image contrast enhancement mechanism for reliable subsurface fingerprint detection. The constructed SD-OCT system achieves a scanning rate up to 60k A-lines/s, and thus, both 3D volumetric images, reaching up to 20 mm mm mm, and en face internal fingerprint furrow pattern images could be obtained. Based upon the analyses of the papillary layer anatomical structures, the contrast enhancement technique not only suppresses image artifacts, but also is effective in detecting fingerprint spoofing. Experiments on healthy subjects have also been conducted to verify the system imaging capability and the effectiveness of the contrast-enhancement technique.
Autors: Xiaojun Yu;Qiaozhou Xiong;Yuemei Luo;Nanshuo Wang;Lulu Wang;Hong Liang Tey;Linbo Liu;
Appeared in: IEEE Photonics Technology Letters
Publication date: Jan 2017, volume: 29, issue:1, pages: 70 - 73
Publisher: IEEE
 
» Control and Modulation Techniques Applied to converters with impedances networks for traction systems
Abstract:
the development of different topologies of power converters with impedance networks have opened up new lines of research, its application in different areas such as transmission systems, high voltage, photovoltaic systems, these have yielded systems with high performance and efficiency, but in recent years its application in research and development of traction systems for electric vehicles have increased, these topologies can be bidirectional and replace the DC-DC booster used in conventional systems. But its implementation is necessary to know the different modulation techniques and control that can be used to reach more eficentes traction system and to consolidate these topologies. This article describes the different modulation and control techniques that can be applied to converter topologies with bidirectional impedance networks for applications in tracction systems for electric vehicle.
Autors: Efren Fernandez;Alejandro Paredes;Vicent Sala;Luis Romeral;
Appeared in: IEEE Latin America Transactions
Publication date: Jan 2017, volume: 15, issue:1, pages: 21 - 30
Publisher: IEEE
 
» Control for Itô Stochastic Systems With Input Delay
Abstract:
This paper examines the long-standing problem of linear quadratic regulation and stabilization for Itô stochastic systems with input delay. This problem remains a primary challenge because the separation principle does not hold for Itô stochastic systems. This paper presents a complete solution to the problem: 1) The (sufficient and necessary) solvability condition of the optimal control and the analytical controller are given based on the modified Riccati differential equation defined herein. 2) The sufficient and necessary stabilization condition in mean square sense is explored. We show that the Itô stochastic system with input delay is stabilized if and only if the modified algebraic Riccati equation developed in this paper has a unique positive-definite solution. The essential obstacle encountered in this paper concerns a Delayed Forward-Backward Stochastic Differential Equation (D-FBSDE), which is mathematical challenging.
Autors: Huanshui Zhang;Juanjuan Xu;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Jan 2017, volume: 62, issue:1, pages: 350 - 365
Publisher: IEEE
 
» Control of a Hybrid AC/DC Microgrid Involving Energy Storage and Pulsed Loads
Abstract:
This paper presents a real-time coordinated control of the hybrid ac/dc microgrids involving energy storage and pulsed loads. Grid-isolated hybrid microgrid applications require special considerations due to the intermittent generation, online energy storage control, and pulsed loads. In this study, we introduce a comprehensive frequency and voltage control scheme for a hybrid ac/dc microgrid consisting of a synchronous generator, solar generation emulator, and bidirectional (ac/dc and dc/dc) converters. A bidirectional controlled ac/dc converter with an active and reactive power decoupling technique is used to link the ac bus with the dc bus, while regulating the system voltage and frequency. A dc/dc boost converter with a maximum power point tracking function is implemented to maximize the intermittent energy generation from solar generators. Current-controlled bidirectional dc/dc converters are applied to connect each lithium-ion battery bank to the dc bus. Lithium-ion battery banks act as energy storage devices that serve to increase the system resiliency by absorbing or injecting power. Experimental results are presented for verification of the introduced hybrid ac/dc power flow control scheme.
Autors: Tan Ma;Mehmet Hazar Cintuglu;Osama A. Mohammed;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Jan 2017, volume: 53, issue:1, pages: 567 - 575
Publisher: IEEE
 
» Control of an Electric Machine Integrated With the Trans-Rotary Magnetic Gear in a Motor Drive Train
Abstract:
This paper studies the dynamic performance of an electric machine integrated with the transrotary magnetic gear (MITROMAG) in a motoring mode of operation. MITROMAG is formed by mechanically coupling a rotary electric machine to the rotor of a trans-rotary magnetic gear (TROMAG). TROMAG is a magnetic device that, through magnetic fields, converts a low-torque, high-speed rotation of its rotor to a high-force, low-speed linear motion of its translator, and vice versa. In a motoring mode of operation, the rotor of the TROMAG is driven by a rotary electric motor, and as a result, its translator drives a reciprocating load. A nonlinear dynamic model is developed for the TROMAG. Oscillation tests are presented as examples of how the model can be used to predict the dynamic behavior of the device. The model is then linearized to derive system transfer functions and study the dynamic response of the MITROMAG to speed commands. Experimental results confirm the analysis.
Autors: Siavash Pakdelian;Morteza Moosavi;Hussain A. Hussain;Hamid A. Toliyat;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Jan 2017, volume: 53, issue:1, pages: 106 - 114
Publisher: IEEE
 
» Control-Layer Routing and Control-Pin Minimization for Flow-Based Microfluidic Biochips
Abstract:
Recent advances in flow-based microfluidic biochips have enabled the emergence of lab-on-a-chip devices for bimolecular recognition and point-of-care disease diagnostics. However, the adoption of flow-based biochips is hampered today by the lack of computer-aided design tools. Manual design procedures not only delay product development but they also inhibit the exploitation of the design complexity that is possible with current fabrication techniques. In this paper, we present the first practical problem formulation for automated control-layer design in flow-based microfluidic very large-scale integration (mVLSI) biochips and propose a systematic approach for solving this problem. Our goal is to find an efficient routing solution for control-layer design with a minimum number of control pins. The pressure-propagation delay, an intrinsic physical phenomenon in mVLSI biochips, is minimized in order to reduce the response time for valves, decrease the pattern set-up time, and synchronize valve actuation. Two fabricated flow-based devices and six synthetic benchmarks are used to evaluate the proposed optimization method. Compared with manual control-layer design and a baseline approach, the proposed approach leads to fewer control pins, better timing behavior, and shorter channel length in the control layer.
Autors: Kai Hu;Trung Anh Dinh;Tsung-Yi Ho;Krishnendu Chakrabarty;
Appeared in: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Publication date: Jan 2017, volume: 36, issue:1, pages: 55 - 68
Publisher: IEEE
 
» Conversion for the Better: A Broadband Highly Efficient Microwave Photonics Detector
Abstract:
Optical fibers have many advant ages over traditional electrical cables and interconnects when it comes to transmitting high-frequency signals. These advantages include lower loss, higher bandwidth, immunity to electromagnetic interference, and lower power consumption. It is due to these advantages that fiber optic links have found widespread use in applications such as radioover-fiber and antenna remoting, where coaxial cable loss increases prohibitively versus frequency.
Autors: Milad Alemohammad;Samuel Ng;Mark Foster;
Appeared in: IEEE Microwave Magazine
Publication date: Jan 2017, volume: 18, issue:1, pages: 58 - 62
Publisher: IEEE
 
» Converter Model for Representing Converter Interfaced Generation in Large Scale Grid Simulations
Abstract:
This paper addresses the positive sequence modeling of converter-based sources in commercial transient stability analysis software. A simple and computationally economical model of the converter has been developed while ensuring a reliable representation of the detailed converter behavior. This model has been implemented as a user defined model in commercial positive sequence software such as PSLF. The behavior of the proposed model in positive sequence has the same form as the behavior obtained from detailed point on wave simulation. Tests have been carried out on a three-generator nine-bus equivalent system and the 18,205 bus Western Electricity Coordinating Council system to assess the impact and performance of the converters. The behavior of these converter interfaced generation sources for various system contingencies has been investigated.
Autors: Deepak Ramasubramanian;Ziwei Yu;Rajapandian Ayyanar;Vijay Vittal;John Undrill;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jan 2017, volume: 32, issue:1, pages: 765 - 773
Publisher: IEEE
 
» Convex Relaxation for Optimal Distributed Control Problems
Abstract:
This paper is concerned with the optimal distributed control (ODC) problem for linear discrete-time deterministic and stochastic systems. The objective is to design a static distributed controller with a prespecified structure that is globally optimal with respect to a quadratic cost functional. It is shown that this NP-hard problem has a quadratic formulation, which can be relaxed to a semidefinite program (SDP). If the SDP relaxation has a rank-1 solution, a globally optimal distributed controller can be recovered from this solution. By utilizing the notion of treewidth, it is proved that the nonlinearity of the ODC problem appears in such a sparse way that an SDP relaxation of this problem has a matrix solution with rank at most 3. Since the proposed SDP relaxation is computationally expensive for a large-scale system, a computationally cheap SDP relaxation is also developed with the property that its objective function indirectly penalizes the rank of the SDP solution. Various techniques are proposed to approximate a low-rank SDP solution with a rank-1 matrix, leading to near globally optimal controllers together with a bound on the optimality degree of each controller. The above results are developed for both finite-horizon and infinite-horizon ODC problems. The SDP relaxations developed in this work are exact for the design of a centralized controller, hence serving as an alternative for solving Riccati equations. The efficacy of the proposed SDP relaxations is elucidated through a case study on the distributed frequency control of power systems.
Autors: Ghazal Fazelnia;Ramtin Madani;Abdulrahman Kalbat;Javad Lavaei;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Jan 2017, volume: 62, issue:1, pages: 206 - 221
Publisher: IEEE
 
» Convex Synthesis of Robust Controllers for Linear Systems With Polytopic Time-Varying Uncertainty
Abstract:
The design of robust controllers for linear systems with structured time-varying uncertainty is a fundamental problem in control systems. This problem is still open because the available methods for robust analysis lead to nonconvex optimization whenever design variables are present. This paper proposes a novel approach that overcomes this difficulty. Specifically, continuous-time linear systems with polytopic time-varying uncertainty are considered. The basic problem consists of designing a robust static output feedback controller ensuring robust asymptotical stability. A novel approach is proposed through the introduction of robust stabilizability functions (RSFs), i.e., functions able to establish whether a controller is robustly asymptotically stabilizing. In particular, RSFs based on homogeneous polynomial Lyapunov functions (HPLFs) are searched for. The proposed approach requires the solution of two convex optimization problems with constraints expressed as linear matrix inequalities (LMIs). For any size of the LMIs, the proposed approach provides a sufficient condition for the existence of a sought controller. Moreover, this condition is also necessary when the size of the LMIs is large enough. Several extensions of the proposed methodology are presented, which deal with the synthesis of controllers ensuring desired decay rate, fixed-order dynamic output controllers, and controllers with the minimum norm.
Autors: Graziano Chesi;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Jan 2017, volume: 62, issue:1, pages: 337 - 349
Publisher: IEEE
 
» Cooperative Cross-Layer Resource Allocation for Self-Healing in Interworking of WLAN and Femtocell Systems
Abstract:
We investigate resource allocation for self-healing in wireless local area network (WLAN) and femtocell interworking system to compensate abrupt network failure. To enable self-healing for the interworking system, we propose a cooperative cross-layer resource allocation scheme based on multiple medium access control layer and physical layer techniques of the two networks. The simulation results demonstrate that the proposed scheme can ensure the fairness between the utilizations of the downlink and the uplink in the WLANs, and improves the system utility while compensating the network failure.
Autors: Yuchen Zhou;Jian Chen;Yonghong Kuo;
Appeared in: IEEE Communications Letters
Publication date: Jan 2017, volume: 21, issue:1, pages: 136 - 139
Publisher: IEEE
 
» Cooperative Local Caching Under Heterogeneous File Preferences
Abstract:
Local caching is an effective scheme for leveraging the memory of the mobile terminal (MT) and short range communications to save the bandwidth usage and reduce the download delay in the cellular communication system. In particular, the MTs first cache in their local memories in off-peak hours and then exchange the requested files with each other in the vicinity during peak hours. However, prior works largely overlook MTs’ heterogeneity in file preferences and their selfish behaviors. In this paper, we practically categorize the MTs into different interest groups according to the MTs’ preferences. Each group of MTs aims to increase the probability of successful file discovery from the neighboring MTs (from the same or different groups). Hence, we define the groups’ utilities as the probability of successfully discovering the file in the neighboring MTs, which should be maximized by deciding the caching strategies of different groups. By modeling MTs’ mobilities as homogeneous Poisson point processes, we analytically characterize MTs’ utilities in the closed form. We first consider the fully cooperative case where a centralizer helps all groups to make caching decisions. We formulate the problem as a weighted-sum utility maximization problem, through which the maximum utility tradeoffs of different groups are characterized. Next, we study two benchmark cases under selfish caching, namely, partial and no cooperation, with and without inter-group file sharing, respectively. The optimal caching distributions for these two cases are derived. Finally, numerical examples are presented to compare the utilities under different cases and show the effectiveness of the fully cooperative local caching compared with the two benchmark cases.
Autors: Yinghao Guo;Lingjie Duan;Rui Zhang;
Appeared in: IEEE Transactions on Communications
Publication date: Jan 2017, volume: 65, issue:1, pages: 444 - 457
Publisher: IEEE
 
» Cooperative Sensing With Joint Energy and Correlation Detection in Cognitive Radio Networks
Abstract:
Cognitive radio networks (CRNs) are a promising solution to address the spectrum shortage issue. Spectrum sensing plays a key role to make such a scenario practical. In this letter, we propose a solution for the problem of spectrum sensing in CRNs aiming to increase the performance of the cooperative spectrum sensing. We design a cooperative spectrum sensing with detection based on two summary statistics, including energy and first-order correlation of the received samples of the signal. The probabilities of detection and false alarm are obtained as criteria for evaluating the performance of the CRNs. The performance evaluation is presented through simulations. The results show that the proposed method significantly improves the detection performance in cooperative spectrum sensing. It also highly decreases the probability of miss-detection in comparison with the traditional energy detection method.
Autors: Morteza Tavana;Ali Rahmati;Vahid Shah-Mansouri;Behrouz Maham;
Appeared in: IEEE Communications Letters
Publication date: Jan 2017, volume: 21, issue:1, pages: 132 - 135
Publisher: IEEE
 
» Cooperative Store–Carry–Forward Scheme for Intermittently Connected Vehicular Networks
Abstract:
Intermittently connected vehicular networks (ICVNs) consist of stationary roadside units (RSUs) deployed along the highway and mobile vehicles. ICVNs are generally infrastructure constrained with a long inter-RSU distance, leading to large dark areas and transmission outage. In this paper, we propose a novel cooperative store–carry–forward (CSCF) scheme to reduce the transmission outage time of vehicles in the dark areas. The CSCF scheme utilizes bidirectional vehicle streams and selects two vehicles in both directions to serve as relays successively for the target vehicle via inter-RSU cooperation. Compared with the existing schemes, simulation results demonstrate that the proposed CSCF scheme has a great advantage in reducing transmission outage time.
Autors: Yuanjie Wang;Yinsheng Liu;Jiayi Zhang;Haina Ye;Zhenhui Tan;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jan 2017, volume: 66, issue:1, pages: 777 - 784
Publisher: IEEE
 
» Coordinated Beamforming for Multi-Cell MIMO-NOMA
Abstract:
In this letter, two novel coordinated beamforming techniques are developed to enhance the performance of non-orthogonal multiple access combined with multiple-input multiple-output communication in the presence of inter-cell interference. The proposed schemes successfully deal with inter-cell interference, and increase the cell-edge users’ throughput, which in turn improves user fairness. In addition, they increase the number of served users, which makes them suitable for 5G networks where massive connectivity and higher spectral efficiency are required. Numerical results confirm the effectiveness of the proposed algorithms.
Autors: Wonjae Shin;Mojtaba Vaezi;Byungju Lee;David J. Love;Jungwoo Lee;H. Vincent Poor;
Appeared in: IEEE Communications Letters
Publication date: Jan 2017, volume: 21, issue:1, pages: 84 - 87
Publisher: IEEE
 
» Coordinated Path Planning for Fixed-Wing UAS Conducting Persistent Surveillance Missions
Abstract:
Algorithms for fixed-wing unmanned aerial systems (UAS) must integrate on-board sensor capabilities and vehicle maneuver constraints to reliably satisfy the objectives of persistent surveillance, path planning, and trajectory management. In many cases, the characteristic dimensions of sensor fields of view are comparable with the turning radius of the UAS platform. Consequently, when persistent, full area, time-critical coverage is required and the number of assets is limited, the complexity of path planning is increased, as the turn radius becomes comparable with or exceeds the sensor footprint. A technique is developed to integrate persistent surveillance mission requirements with sensor resolution and field-of-view to facilitate efficient path planning. Graph search techniques and spline-based methods are combined to develop computationally simple algorithms that converge to feasible paths with continuity. ( continuity in this context means the path, which is constructed from a concatenated series of curve segments, and its derivatives are continuous through two derivatives, but the magnitudes of second derivatives may differ at the boundaries, where these curve segments are joined to form the entire path. Curvature is continuous throughout.) Two example cases are provided. In the first, the turning radius is small in comparison with the sensor footprint, while in the second, the minimum turn radius is a critical parameter in the determination of a feasible path.
Autors: James Keller;Dinesh Thakur;Maxim Likhachev;Jean Gallier;Vijay Kumar;
Appeared in: IEEE Transactions on Automation Science and Engineering
Publication date: Jan 2017, volume: 14, issue:1, pages: 17 - 24
Publisher: IEEE
 
» Coordinated Regularized Zero-Forcing Precoding for Multicell MISO Systems With Limited Feedback
Abstract:
We investigate coordinated regularized zero-forcing (RZF) precoding for limited feedback multicell multiuser (MU) multiple-input–single-output (MISO) systems. We begin by deriving an approximation to the expected signal-to-interference-plus-noise (SINR) ratio for the proposed scheme with perfect channel direction information (CDI) at the base station (BS). We also derive an expected SINR approximation for limited feedback systems with random vector quantization (RVQ)-based codebook CDI at the BS. Using the expected interference result for the RVQ-based limited feedback CDI, we propose an adaptive feedback bit allocation strategy to minimize the expected interference by partitioning the total number of bits between the serving and out-of-cell interfering channels. Numerical results show that the proposed adaptive feedback bit allocation method offers a spectral efficiency gain over the existing coordinated zero-forcing (ZF) scheme.
Autors: Jawad Mirza;Peter J. Smith;Pawel A. Dmochowski;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jan 2017, volume: 66, issue:1, pages: 335 - 343
Publisher: IEEE
 
» Coordinated Scheduling for Interdependent Electric Power and Natural Gas Infrastructures
Abstract:
The extensive installation of gas-fired power plants in many parts of the world has led electric systems to depend heavily on reliable gas supplies. The use of gas-fired generators for peak load and reserve provision causes high intraday variability in withdrawals from high-pressure gas transmission systems. Such variability can lead to gas price fluctuations and supply disruptions that affect electric generator dispatch, electricity prices, and threaten the security of power systems and gas pipelines. These infrastructures function on vastly different spatio-temporal scales, which prevents current practices for separate operations and market clearing from being coordinated. In this paper, we apply new techniques for control of dynamic gas flows on pipeline networks to examine day-ahead scheduling of electric generator dispatch and gas compressor operation for different levels of integration, spanning from separate forecasting, and simulation to combined optimal control. We formulate multiple coordination scenarios and develop tractable physically accurate computational implementations. These scenarios are compared using an integrated model of test networks for power and gas systems with 24 nodes and 24 pipes, respectively, which are coupled through gas-fired generators. The analysis quantifies the economic efficiency and security benefits of gas–electric coordination and dynamic gas system operation.
Autors: Anatoly Zlotnik;Line Roald;Scott Backhaus;Michael Chertkov;Göran Andersson;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jan 2017, volume: 32, issue:1, pages: 600 - 610
Publisher: IEEE
 
» Corporate-Feed Slotted Waveguide Array Antenna in the 350-GHz Band by Silicon Process
Abstract:
A corporate-feed slotted waveguide array antenna with broadband characteristics in terms of gain and reflection in the 350-GHz band is proposed. To improve the etching accuracy of the thin laminated plates with the conventional diffusion bonding process, a new fabrication process has been developed, where the etching accuracy is lower than . In this process, the laminated plates are made with silicon wafers and etched by deep reactive ion etcher process. These are gold plated then bonded with the diffusion bonding process. The estimated effective conductivity of the gold plated wafer is S/m. The loss per unit length is 1.1 dB/cm. A element array antenna has been designed and fabricated in the 350-GHz band with the proposed process. The broadband characteristic in terms of the antenna gain is demonstrated for the first time by measurement in this frequency band. The 3-dB down gain bandwidth is 50.8 GHz in simulation and is 44.6 GHz in measurement.
Autors: Karim Tekkouk;Jiro Hirokawa;Kazuki Oogimoto;Tadao Nagatsuma;Hiroyuki Seto;Yoshiyuki Inoue;Mikiko Saito;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Jan 2017, volume: 65, issue:1, pages: 217 - 225
Publisher: IEEE
 
» Correction to “Scalable High-Performance Image Registration Framework by Unsupervised Deep Feature Representations Learning”
Abstract:
Presents corrections to the paper, "Scalable high performance image registration framework by unsupervised deep feature representations", (Wu, G. et al.), IEEE Trans. Biomed. Eng., vol. 63, no. 7, pp. 1505–1516, Jul. 2016.
Autors: Guorong Wu;Minjeong Kim;Qian Wang;Brent C. Munsell;Dinggang Shen;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Jan 2017, volume: 64, issue:1, pages: 250 - 250
Publisher: IEEE
 
» Correction to “Relative Observability of Discrete-Event Systems and Its Supremal Sublanguages”
Abstract:
In this note, we make a few corrections to our previous paper “Relative Observability of Discrete-Event Systems and Its Supremal Sublanguages.”
Autors: Kai Cai;Renyuan Zhang;W. M. Wonham;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Jan 2017, volume: 62, issue:1, pages: 511 - 511
Publisher: IEEE
 
» Corrections to “A Global High-Gain Finite-Time Observer”
Abstract:
This note fixes the proof of Theorem 2 in the above paper.
Autors: Tomas Ménard;Emmanuel Moulay;Wilfrid Perruquetti;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Jan 2017, volume: 62, issue:1, pages: 509 - 510
Publisher: IEEE
 
» Corrections to “AlGaN/GaN HEMTs With Damage-Free Neutral Beam Etched Gate Recess for High-Performance Millimeter-Wave Applications”
Abstract:
In the above paper [1], the first footnote should have included the following information.
Autors: Yen-Ku Lin;Shuichi Noda;Hsiao-Chieh Lo;Shih-Chien Liu;Chia-Hsun Wu;Yuen-Yee Wong;Quang Ho Luc;Po-Chun Chang;Heng-Tung Hsu;Seiji Samukawa;Edward Yi Chang;
Appeared in: IEEE Electron Device Letters
Publication date: Jan 2017, volume: 38, issue:1, pages: 149 - 149
Publisher: IEEE
 
» Cortical Source Localization and Signal Estimation Without Exact Knowledge of the Leadfield Matrix
Abstract:
This paper develops an iterative algorithm for cerebral activity localization and signal estimation when exact knowledge of the leadfield matrix is not available. The algorithm exploits a high resolution localization technique that can determine the number of sources and their locations. A beamformer is designed in order to estimate the dipole source amplitudes, and the EEG signal is reconstructed via a calibration matrix. The performance of the algorithm is quantified in terms of the localization error and the accuracy is validated by applying it to experimental data.
Autors: Rabiya Momin;Hasan Mir;Hasan Al-Nashash;
Appeared in: IEEE Sensors Journal
Publication date: Jan 2017, volume: 17, issue:2, pages: 450 - 458
Publisher: IEEE
 
» Cost Efficiency for Economical Mobile Data Traffic Management From Users’ Perspective
Abstract:
Explosive demand for wireless internet services has posed critical challenges for wireless networks due to their limited capacity. To tackle this hurdle, wireless Internet service providers (WISPs) take the smart data pricing to manage data traffic loads. Meanwhile, from the users’ perspective, it is also reasonable and desired to employ mobile data traffic management under the pricing policies of WISPs to improve the economic efficiency of data consumption. In this paper, we introduce a concept of cost efficiency (CE) for user’s mobile data management, defined as the ratio of user’s mobile data consumption benefits and its expense. We propose an integrated CE-based data traffic management scheme, including long-term data demand planning, short-term data traffic pre-scheduling, and real-time data traffic management. The real-time data traffic management algorithm is proposed to coordinate user’s data consumption to tailor to the pre-scheduled data traffic profile. Numerical results demonstrate the effectiveness of CE framework in indicating and motivating mobile user’s data consumption behavior. The proposed management scheme can effectively motivate the user to adjust its data consumption profile to obtain the optimal data consumption CE.
Autors: Jinghuan Ma;Lingyang Song;Yonghui Li;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Jan 2017, volume: 16, issue:1, pages: 362 - 375
Publisher: IEEE
 
» Cost Minimization Algorithms for Data Center Management
Abstract:
Due to the increasing usage of cloud computing applications, it is important to minimize energy cost consumed by a data center, and simultaneously, to improve quality of service via data center management. One promising approach is to switch some servers in a data center to the idle mode for saving energy while to keep a suitable number of servers in the active mode for providing timely service. In this paper, we design both online and offline algorithms for this problem. For the offline algorithm, we formulate data center management as a cost minimization problem by considering energy cost, delay cost (to measure service quality), and switching cost (to change servers’s active/idle mode). Then, we analyze certain properties of an optimal solution which lead to a dynamic programming based algorithm. Moreover, by revising the solution procedure, we successfully eliminate the recursive procedure and achieve an optimal offline algorithm with a polynomial complexity. For the online algorithm, We design it by considering the worst case scenario for future workload. In simulation, we show this online algorithm can always provide near-optimal solutions.
Autors: Lei Shi;Yi Shi;Xing Wei;Xu Ding;Zhenchun Wei;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Jan 2017, volume: 28, issue:1, pages: 60 - 71
Publisher: IEEE
 
» Cost-Reliability Tradeoff in Licensed and Unlicensed Spectra Interoperable Networks With Guaranteed User Data Rate Requirements
Abstract:
Unlicensed spectra access holds the promise of alleviating licensed spectra scarcity and providing super high-rate mobile data services, which has been viewed as one of the key technologies of fifth generation (5G) cellular networks. In this paper, we first design a framework for 5G licensed and unlicensed spectra interoperable networks based on the cloud radio access network technology and the control/data decoupled architecture. Then, we investigate network-level cost-reliability tradeoff from two aspects. First, we study a fundamental tradeoff between the cost and the reliability by minimizing cost for a given reliability level. Second, we define a quality of experience efficiency utility as the complementary measure to characterize the cost and the reliability, offering an inherent tradeoff between them. Moreover, an interference power estimation method is proposed to more accurately estimate channel states to guarantee resource allocation effectiveness. Finally, we conduct extensive simulation study and demonstrate the effectiveness of the interference power estimation method.
Autors: Hao Song;Xuming Fang;Cheng-Xiang Wang;
Appeared in: IEEE Journal on Selected Areas in Communications
Publication date: Jan 2017, volume: 35, issue:1, pages: 200 - 214
Publisher: IEEE
 
» Coupled Ridge Waveguide Substrate-Emitting DFB Quantum Cascade Laser Arrays
Abstract:
A coupled ridge waveguide substrate-emitting quantum cascade laser array operating at m was presented. Fifteen elements were integrated in parallel to get high peak power and improved beam quality. The device was operating at fundamental supermode with a single-lobed far-field pattern. A narrow divergence angle of 2.9° in the ridge-width direction and 0.36° in the cavity-length direction were obtained by carefullydesigning the coupled ridge waveguide structure.Single-mode emission was observed by employing a buried second-orderdistributed-feedback grating. The peak power of the device was more than 2 W in pulsed operation at room temperature. This letter showed great potential to enlarge the output power of the surface-emitting devices while maintaining good beam quality.
Autors: Chuan-Wei Liu;Jin-Chuan Zhang;Zhi-Wei Jia;Yue Zhao;Ning Zhuo;Shen-Qiang Zhai;Li-Jun Wang;Jun-Qi Liu;Shu-Man Liu;Feng-Qi Liu;Zhan-Guo Wang;
Appeared in: IEEE Photonics Technology Letters
Publication date: Jan 2017, volume: 29, issue:2, pages: 213 - 216
Publisher: IEEE
 
» Coupling-Shielded Inductor for High Isolation Between PA and LC-Based DCO
Abstract:
This letter presents a novel coupling-shielded inductor. The inductor has a magnetic coupling shield ring (CSR), designed with an Al pad metal. The CSR has an electromotive force-induced current, which flows in such a direction as to oppose the magnetic field from an aggressor. As a result, the proposed inductor can be protected from the attack of a power amplifier (PA) with a strong magnetic field. The inductor is applied in an -based digitally controlled oscillator (DCO) to verify the enhancement of isolation. It was fabricated by a 55-nm 1P6M CMOS process. Using the CSR, the isolation between the DCO and PA is increased by about 11 dB without degradation of the DCO performance. The DCO with CSR has a low phase noise of −114.5 dBc/Hz at 1 MHz with 0.74-mW power consumption.
Autors: Sang-Sun Yoo;Kang-Yoon Lee;Hyung-Joun Yoo;
Appeared in: IEEE Electron Device Letters
Publication date: Jan 2017, volume: 38, issue:1, pages: 24 - 27
Publisher: IEEE
 
» Coverage Analysis of Cloud Radio Networks With Finite Clustering
Abstract:
Cloud radio networks coordinate transmission among base stations (BSs) to reduce the interference effects, particularly for the cell-edge users. In this paper, we analyze the performance of a cloud network with static clustering where geographically close BSs form a cloud network of cooperating BSs. Due to finite cooperation, the interference in a practical cloud radio cannot be removed, and in this paper, the distance-based interference is taken into account in the analysis. In particular, we consider centralized zero forcing equalizer and dirty paper precoding for canceling the interference. Bounds are developed on the signal-to-interference ratio distribution and achievable rate with full and limited channel feedback from the cluster users. The adverse effect of finite clusters on the achievable rate is quantified. We show that the number of cooperating BSs is more crucial than the cluster area when full channel state information from the cluster is available for precoding. Also, we study the impact of limiting the channel state information on the achievable rate. We show that even with a practically feasible feedback of about five to six channel states from each user, significant gain in mean rate and cell edge rate compared with conventional cellular systems can be obtained.
Autors: Sreejith T. Veetil;Kiran Kuchi;Radha Krishna Ganti;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Jan 2017, volume: 16, issue:1, pages: 594 - 606
Publisher: IEEE
 
» Coverage Analysis of Packet Multi-Tier Networks With Asynchronous Slots
Abstract:
Using stochastic geometry, the downlink (DL) and uplink (UL) coverage probabilities are derived for co-channel packet multi-tier heterogeneous cellular networks (HCNs). The spatial locations of base stations (BSs) as well as user equipments (UEs) are modeled as independent spatial homogeneous Poisson point processes. The decoupled association is evaluated where the UE may connect to different BSs in the UL and DL transmissions. Unlike most of the existing works, the packet transmission slots are not synchronized, that is, the starting and ending points of the slots are not aligned. We investigate fundamental performance metrics of dynamic packet HCN for two traffic models, namely, the slotted-asynchronous and exponential-interarrival. Furthermore, tight lower bounds for the DL and UL coverage probabilities for two traffic models are obtained. The derived bounds are tight especially in high data rate regimes. The analysis provided herein enables us to determine the performance limits of packet-based HCNs with possible asynchronous time-slots. Simulation results are conducted to verify the analytical derivations. Furthermore, the performance comparison between pure synchronous and asynchronous packet-based systems is provided. The results confirm that the synchronous case outperforms the asynchronous one in terms of the UL and DL coverage probabilities at the cost of higher computational complexity.
Autors: Vahid Naghshin;Mark C. Reed;Neda Aboutorab;
Appeared in: IEEE Transactions on Communications
Publication date: Jan 2017, volume: 65, issue:1, pages: 200 - 215
Publisher: IEEE
 
» Cozying Up to Complexity [Reflections]
Abstract:
I enjoyed Samuel Arbesman’s first book, The Half-Life of Facts, which was a discussion of the exponential pace of change, as exemplified by Moore’s Law, among other things. When I saw the title of his new book, Overcomplicated, I assumed that it would be a warning that we technologists had gone too far in creating complex systems. It would advocate moving to simpler systems, just as a doctor might advise an overweight person to go on a diet. I was prepared to argue against such a conclusion, but as I discovered upon reading the book, Arbesman does not say that complexity is necessarily bad or that we should seek simplicity. Instead, he maintains that systems are now unknowably complex, that they will become even more so, and we should…just get over it.
Autors: Robert W. Lucky;
Appeared in: IEEE Spectrum
Publication date: Jan 2017, volume: 54, issue:1, pages: 24 - 24
Publisher: IEEE
 
» Cross-Device Wi-Fi Map Fusion with Gaussian Processes
Abstract:
We investigate the use of linear adaptation when fusing Wi-Fi maps built from spatially sparse received signal strength measurements obtained with multiple devices. First, we show that the residual of the linear regression between devices, usually unaccounted for in existing cross-device localization work, is an important indicator of device dissimilarity and a good predictor of localization performance. Through explicitly modeling the device dissimilarity, one can improve localization accuracy when fusing training sets from multiple devices by weighting each training set differently. Second, we use the Gaussian process (GP) sensor model to develop a regression algorithm which more reliably estimates the linear fit and device dissimilarity given only a few labeled samples from each new device. By accounting for device dissimilarities in map fusion and by using the proposed regression algorithm, localization performance can be greatly improved given just a few training samples from a new device. Also, when fusing multiple existing maps for a new device using regression misfit, performance is improved by 3.5 to 10 percent.
Autors: Hsiao-Chieh Yen;Chieh-Chih Wang;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: Jan 2017, volume: 16, issue:1, pages: 44 - 57
Publisher: IEEE
 
» Cross-Layer Routing and Scheduling for Onboard Processing Satellites with Phased Array Antenna
Abstract:
The advanced multibeam satellite equipped with phased array antenna and solid state power amplifiers can generate flexible beams, by managing interbeam interference to serve a very large number of users effectively over its coverage area. Onboard processing (OBP) functionality can enhance the flexibility of a large-scale antenna by speeding up computational processes and saving precious radio link spectrum. In this paper, we derive a cross-layer OBP design of switching/routing, beamforming, and user scheduling as taking advantage of fine spatial resolution capability of phased array antenna satellites. We evaluate tradeoff between OBP computational complexity and throughput performance, showing that the additional complexity of an increased number of switch ports and phased array antenna gain patterning is compensated by high throughput gain achieved by mitigating interference. Our analysis shows that throughput gain for the next generation satellite system can be as high as 40, compared with the conventional multiple beam antenna with travelling wave tube amplifiers, and that beamforming is critical for achieving high spectral efficiency in the crowded service area. We then investigate the impacts of onboard switching and phased array antenna beamforming to practical routing protocols, such as open short path first and routing information protocol.
Autors: Jihwan P. Choi;Seok-Ho Chang;Vincent W. S. Chan;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Jan 2017, volume: 16, issue:1, pages: 180 - 192
Publisher: IEEE
 
» CSI-Based Fingerprinting for Indoor Localization: A Deep Learning Approach
Abstract:
With the fast-growing demand of location-based services in indoor environments, indoor positioning based on fingerprinting has attracted significant interest due to its high accuracy. In this paper, we present a novel deep-learning-based indoor fingerprinting system using channel state information (CSI), which is termed DeepFi. Based on three hypotheses on CSI, the DeepFi system architecture includes an offline training phase and an online localization phase. In the offline training phase, deep learning is utilized to train all the weights of a deep network as fingerprints. Moreover, a greedy learning algorithm is used to train the weights layer by layer to reduce complexity. In the online localization phase, we use a probabilistic method based on the radial basis function to obtain the estimated location. Experimental results are presented to confirm that DeepFi can effectively reduce location error, compared with three existing methods in two representative indoor environments.
Autors: Xuyu Wang;Lingjun Gao;Shiwen Mao;Santosh Pandey;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jan 2017, volume: 66, issue:1, pages: 763 - 776
Publisher: IEEE
 
» Current Harmonics in Induction Machine With Closed-Slot Rotor
Abstract:
Usually an induction machine with closed slots on the rotor has lower harmonics in stator line currents than that with open slots. However, some induction machines with closed-rotor slots may suffer from local saturation in the rotor slot bridges, and thus, exhibit significant low-order time harmonics in the stator currents. Such phenomenon is revealed with theoretical analysis, and validated with both finite element analysis and experiments. This study is of reference value for the induction machine design so as to avoid the low-order current harmonics.
Autors: Gui-Yu Zhou;Jian-Xin Shen;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Jan 2017, volume: 53, issue:1, pages: 134 - 142
Publisher: IEEE
 
» Current Sensorless Equalization Strategy for a Single-Switch Voltage Equalizer Using Multistacked Buck–Boost Converters for Photovoltaic Modules Under Partial Shading
Abstract:
Differential power processing converters and voltage equalizers have been proposed and used for photovoltaic strings comprising multiple modules/substrings connected in series in order to preclude negative influences of partial shading. The single-switch voltage equalizer using multistacked buck–boost converters can significantly reduce the necessary switch count compared to that of conventional topologies, achieving simplified circuitry. However, multiple current sensors are necessary for this single-switch equalizer to effectively perform equalization. In this paper, a current sensorless equalization technique (ΔV-controlled equalization) is presented. The equalization strategy using the ΔV-controlled equalization is explained and discussed on the basis of comparison with current-controlled equalization strategies. Experimental equalization tests emulating partial-shading conditions were performed using the single-switch equalizer employing the ΔV -controlled equalization. Negative impacts of partial shading were successfully precluded, demonstrating the efficacy of the proposed ΔV-controlled equalization strategy.
Autors: Masatoshi Uno;Akio Kukita;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Jan 2017, volume: 53, issue:1, pages: 420 - 429
Publisher: IEEE
 
» Current-Based Measurement Technique for High Sensitivity Detection of Resistive Bridges With External Balancing Through Control Voltages
Abstract:
We present a novel approach based on differential measurements of dc currents with very high sensitivity suitable for the detection of very small variations of resistors in Wheatstone full-bridge configurations. External control voltages allow for the compensation of the bridge unbalancing avoiding the need of changing its elements so making the solution suitable for integrated sensor systems. The proposed current-based measurement technique has been implemented through three different circuits, in transimpedance configuration and without the use of any further amplification stage, employing only two active blocks that allow for a very high integration level. The main characteristics of these solutions, developed both in current-mode (CM) and voltage-mode (VM) approaches, have been preliminary evaluated through PSPICE simulations so validating the new approach. The results have demonstrated the capability of the presented circuits to reveal, with linear responses, relative variations of the bridge resistors lower than 10−6% with respect to their nominal values, providing detection sensitivities up to 150 V/% (i.e., /%) with the CM solutions and 1750 V/% in the case of the VM scheme. Moreover, experimental measurements have also been conducted by implementing the new technique on breadboard with discrete commercial components confirming the performances of the proposed approach. In this regard, a detection resolution of resistive variations as low as 0.00008%, corresponding to about , has been achieved in the measurement of only one resistor of the bridge with an improvement of the detection sensitivity of a factor 500 with respect to the standard basic resistive bridg .
Autors: Andrea De Marcellis;Càndid Reig;María-Dolores Cubells-Beltrán;
Appeared in: IEEE Sensors Journal
Publication date: Jan 2017, volume: 17, issue:2, pages: 404 - 411
Publisher: IEEE
 
» Current-Limiting Fuses: New NFPA 70-2017 Section 240.67, Arc Modeling, and an Assessment Based on the IEEE 1584-2002
Abstract:
When operating in current-limiting mode, current-limiting fuses can effectively mitigate the heat and pressure hazards associated with an arc event because they limit the current in the first one-quarter cycle and interrupt current flow in less than 8.3 ms. The effectiveness of current-limiting fuses is reinforced by their inclusion in NFPA 70E-2015: Note to Table 130.7(C)(15)(A)(b), Annex D.4.6, and Annex O.2.4(4). The incident energy levels associated with current-limiting fuses can be determined from the IEEE Standard 1584-2002, IEEE Guide for Performing Arc-Flash Hazard Calculations. IEEE 1584-2002 presents a method for directly determining incident energy without first determining arc current or arc duration. The fuse equations were derived from 600-V arc tests involving a range of current-limiting fuse sizes. These data are reviewed to assess the performance of current-limiting fuses in reducing arc energy in accordance with NFPA 70-2017 Section 240.67. The IEEE 1584-2002 equations are used to assess the performance of these fuses in comparison with an arc energy reduction maintenance switch and the combination of both technologies. The viability of predicting arc current and incident energy for installations involving current-limiting fuses and implementing NEC Section 240.67 using general arc models is discussed.
Autors: Tammy Gammon;Vincent Saporita;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Jan 2017, volume: 53, issue:1, pages: 608 - 614
Publisher: IEEE
 
» Curriculum Considerations for the Internet of Things
Abstract:
Before IoT innovations can be broadly realized, we must consider the educational needs of those who will develop the IoT products and services of the future. This article sets forth curriculum topics for institutions to use when creating and evaluating new IoT-inclusive curricula.
Autors: Jeffrey Voas;Philip Laplante;
Appeared in: Computer
Publication date: Jan 2017, volume: 50, issue:1, pages: 72 - 75
Publisher: IEEE
 
» Cyclic Statistic Estimators With Uncertain Cycle Frequencies
Abstract:
For almost-cyclostationary processes, sufficient conditions are derived, such that estimates of the second-order cyclic probabilistic functions with estimated cycle frequencies are mean-square consistent and asymptotically complex normal. Cyclic (conjugate) autocorrelation functions and cyclic (conjugate) spectra are considered. Under the derived conditions, asymptotically, as the data-record length approaches infinity, the estimates of cyclic statistics with estimated cycle frequencies have the same complex normal distribution as the case of exactly known cycle frequencies. The results are applied to the detection of a moving cyclostationary source in the presence of strong Doppler effect and for low values of SNR.
Autors: Antonio Napolitano;
Appeared in: IEEE Transactions on Information Theory
Publication date: Jan 2017, volume: 63, issue:1, pages: 649 - 675
Publisher: IEEE
 
» DAC-Less 32-GBd PDM-256-QAM Using Low-Power InP IQ Segmented MZM
Abstract:
We demonstrate DAC-less generation and transmission of 256-quadrature amplitude modulation signals at a symbol rate of 32 GBd using an indium phosphide segmented Mach–Zehnder modulator with 15 active sections and dedicated BiCMOS driver arrays. The linear quantization characteristic of the segmented modulator with 4-bit resolution allows the generation of spectrally efficient modulation formats without any transmitter side signal processing. The chip power consumption of 1.64 W translates into the record-low energy per bit of 6.4 pJ/b. Back-to-back performance is evaluated and two different low-density parity check codes enable error-free transmission over 80 and 120 km with a net data rate of 320 and 240 Gb/s, respectively.
Autors: A. Aimone;F. Frey;R. Elschner;I. Garcia Lopez;G. Fiol;P. Rito;M. Gruner;A. C. Ulusoy;D. Kissinger;J. K. Fischer;C. Schubert;M. Schell;
Appeared in: IEEE Photonics Technology Letters
Publication date: Jan 2017, volume: 29, issue:2, pages: 221 - 223
Publisher: IEEE
 
» Dark Channel Prior-Based Altitude Extraction Method for a Single Mountain Remote Sensing Image
Abstract:
The altitude information of single remote sensing image may aid in detecting natural disasters such as landslides or mud-rock flow. Accordingly, in this letter, an approach based on dark channel prior is proposed for the altitude extraction of single remote sensing image, and it also overcomes the effect of mountain shadow. We first detect the mountain shadows based on machine learning, and then adjust the brightness of each shadow with an adaptive adjustment parameter. Next, we estimate the altitude information based on dark channel prior, including atmospheric light calculation and soft matting. The experimental results with real mountain remote sensing images demonstrate that the proposed algorithm can obtain the accurate relative altitude information, which is effective for the extraction of the relative altitude of single mountain remote sensing image with shadows.
Autors: Tingting Sheng;Qiang Chen;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Jan 2017, volume: 14, issue:1, pages: 132 - 136
Publisher: IEEE
 
» Darkitecture: The Reality Skirted by Architecture
Abstract:
Just as physicists infer dark matter's presence on the basis of its gravitational effects on visible matter, we can conceptualize a "darkitecture" that outlines visible software architectures.
Autors: Balaji Prasad;
Appeared in: IEEE Software
Publication date: Jan 2017, volume: 34, issue:1, pages: 103 - 105
Publisher: IEEE
 

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