Electrical and Electronics Engineering publications abstract of: 11-2017 sorted by title, page: 4

» BOOST: Base Station on-off Switching Strategy for Green Massive MIMO HetNets
Abstract:
We investigate the problem of base station (BS) on-off switching, user association, and power control in a heterogeneous network (HetNet) with massive multiple input multiple output (MIMO), aiming to turn off under-utilized BS’s and maximize the system energy efficiency. With a mixed integer programming problem formulation, we first develop a centralized scheme to derive the near optimal BS on-off switching, which is an iterative framework with proven convergence. We further propose two distributed schemes based on game theory, with a bidding game between users and BS’s, and a pricing game between wireless service provider and users. Both games are proven to achieve a Nash Equilibrium. Simulation studies demonstrate the efficacy of the proposed schemes.
Autors: Mingjie Feng;Shiwen Mao;Tao Jiang;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Nov 2017, volume: 16, issue:11, pages: 7319 - 7332
Publisher: IEEE
 
» Bounds on Variance for Unimodal Distributions
Abstract:
We show a direct relationship between the variance and the differential entropy for subclasses of symmetric and asymmetric unimodal distributions by providing an upper bound on variance in terms of entropy power. Combining this bound with the well-known entropy power lower bound on variance, we prove that the variance of the appropriate subclasses of unimodal distributions can be bounded below and above by the scaled entropy power. As the differential entropy decreases, the variance is sandwiched between two exponentially decreasing functions in the differential entropy. This establishes that for the subclasses of unimodal distributions, the differential entropy can be used as a surrogate for concentration of the distribution.
Autors: Hye Won Chung;Brian M. Sadler;Alfred O. Hero;
Appeared in: IEEE Transactions on Information Theory
Publication date: Nov 2017, volume: 63, issue:11, pages: 6936 - 6949
Publisher: IEEE
 
» Branch-Line Couplers With Arbitrary Coupling Value Through the Electrical Length Variation With Fixed Line Impedances
Abstract:
A new method is presented to obtain arbitrary coupling levels of the branch-line couplers through the simple modification of the 3-dB coupler. It is shown that the coupling of the conventional 3-dB branch-line coupler can be adjusted to arbitrary values by varying the electrical length of the branches without changing the impedances. A very wide range of coupling values can easily be obtained using the same line impedances as the conventional 3-dB couplers based on the proposed method.
Autors: Jaegook Lee;Jongchul Lee;Myun-Joo Park;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Nov 2017, volume: 27, issue:11, pages: 968 - 970
Publisher: IEEE
 
» Breakdown Enhancement and Current Collapse Suppression by High-Resistivity GaN Cap Layer in Normally-Off AlGaN/GaN HEMTs
Abstract:
In this letter, a device structure of high-resistivity-cap-layer HEMT (HRCL-HEMT) is developed for normally-off p-GaN gate HEMT toward high breakdown voltage and low current collapse. It demonstrates that the breakdown capability and current collapse of the device were effectively improved due to the introduction of a thick HR-GaN cap layer. The fabricated HRCL-HEMT exhibits a high breakdown voltage of 1020 V at /mm with the substrate grounded. Meanwhile, the dynamic is only 2.4 times the static after off-state stress of 1000 V with the substrate grounded (the OFF to ON switching time interval is set to ).
Autors: Ronghui Hao;Weiyi Li;Kai Fu;Guohao Yu;Liang Song;Jie Yuan;Junshuai Li;Xuguang Deng;Xiaodong Zhang;Qi Zhou;Yaming Fan;Wenhua Shi;Yong Cai;Xinping Zhang;Baoshun Zhang;
Appeared in: IEEE Electron Device Letters
Publication date: Nov 2017, volume: 38, issue:11, pages: 1567 - 1570
Publisher: IEEE
 
» Broadband Oscillator-Free THz Pulse Generation and Radiation Based on Direct Digital-to-Impulse Architecture
Abstract:
Broadband 0.03–1.1 THz signal generation and radiation are demonstrated based on an oscillator-free direct digital-to-impulse architecture with a 1.9-ps full width at half maximum and 130-GHz 3-dB bandwidth (BW) (200-GHz 10-dB BW) centered at 160 GHz. The radiated pulse achieves a peak pulse effective isotropic-radiated power of 19.2 dBm and peak pulse-radiated power of 2.6 mW. An ON/OFF impulse-shaping technique is introduced and implemented to suppress undesired ringing and to increase dc-to-radiated efficiency. The frequency-comb spectrum of the radiated pulse train with 5.2-GHz repetition rate is measured up to 1.1 THz. At a distance of 4 cm, the measured received SNR at 1 and 1.1 THz is 28 and 22 dB, respectively. A 1.1-THz tone is measured with a 10-dB spectral width of 2 Hz, demonstrating an extremely narrow spectral line width (two parts per trillion). Time-domain picosecond pulses are characterized using a custom femtosecond-laser-based terahertz time-domain spectroscopy system. Coherent spatial combining from two widely spaced chips is demonstrated. It is shown that the starting time of the radiated pulses is locked to the edge of the input digital trigger with a timing jitter of 270 fs. The chip is fabricated in a 130-nm SiGe BiCMOS process technology.
Autors: M. Mahdi Assefzadeh;Aydin Babakhani;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Nov 2017, volume: 52, issue:11, pages: 2905 - 2919
Publisher: IEEE
 
» Broadband Permeability Spectra of Flake-Shaped Ferromagnetic Particle Composites
Abstract:
Broadband permeability spectra of aligned ferromagnetic flakes embedded in a nonmagnetic polymer matrix have been measured using an APC-7 coaxial line within the frequency range 10 MHz–18 GHz. These spectra reveal two well-defined resonance lines. The low-frequency one (sub-GHz range) has previously been attributed to the fundamental vortex translation mode in a multidomain magnetic structure, whereas the high-frequency resonance (beyond 1 GHz) is assigned to the natural spin resonance. A two-level analytical model combining a spin dynamics description including these two contributions at the flake scale and a Maxwell–Garnett mixing rule at the composite scale has been developed and reproduces very satisfactorily the experimental spectra in terms of resonance frequencies, resonance linewidths, and resonance mode amplitudes.
Autors: Z. Raolison;Q. Clément;A.-L. Adenot-Engelvin;N. Malléjac;C. Lefevre;G. Pourroy;F. Boust;N. Vukadinovic;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Bubble Entropy: An Entropy Almost Free of Parameters
Abstract:
Objective: A critical point in any definition of entropy is the selection of the parameters employed to obtain an estimate in practice. We propose a new definition of entropy aiming to reduce the significance of this selection. Methods: We call the new definition Bubble Entropy. Bubble Entropy is based on permutation entropy, where the vectors in the embedding space are ranked. We use the bubble sort algorithm for the ordering procedure and count instead the number of swaps performed for each vector. Doing so, we create a more coarse-grained distribution and then compute the entropy of this distribution. Results: Experimental results with both real and synthetic HRV signals showed that bubble entropy presents remarkable stability and exhibits increased descriptive and discriminating power compared to all other definitions, including the most popular ones. Conclusion: The definition proposed is almost free of parameters. The most common ones are the scale factor r and the embedding dimension m . In our definition, the scale factor is totally eliminated and the importance of m is significantly reduced. The proposed method presents increased stability and discriminating power. Significance: After the extensive use of some entropy measures in physiological signals, typical values for their parameters have been suggested, or at least, widely used. However, the parameters are still there, application and dataset dependent, influencing the computed value and affecting the descriptive power. Reducing their significance or eliminating them alleviates the problem, decoupling the method from the data and the application, and eliminating subjective factors.
Autors: George Manis;Md Aktaruzzaman;Roberto Sassi;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Nov 2017, volume: 64, issue:11, pages: 2711 - 2718
Publisher: IEEE
 
» Buffer-Aided Relay Selection for Cooperative Relay Networks With Certain Information Rates and Delay Bounds
Abstract:
In this paper, we propose a relay selection scheme for cooperative buffer-aided relay networks with specific information rates and delay bounds. The proposed scheme differs from most of the well-known schemes in the literature that assume the source is saturated with data and/or without delay constraints. The proposed scheme is designed to encompass the delay-sensitive applications that are subject to delay limits and have certain rates. The proposed scheme exploits the channel state information, buffer state information, and delay state information to minimize the outage probability and achieve higher throughput. To achieve that, it uses these information to compromise between the selections of relays for reception and transmission. The proposed scheme is analyzed in the independent and identically distributed and independent and nonidentically distributed Rayleigh fading channels. The analysis is in terms of outage probability, packet dropping probability of the source node, packet dropping probability of the entire system, and throughput. For systems with high delay constraints, simulation results show that the proposed scheme offers lower packet dropping probability and higher throughput as compared to the renowned relay selection schemes.
Autors: Ali Ahmed Mohamed Siddig;Mohd Fadzli Mohd Salleh;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Nov 2017, volume: 66, issue:11, pages: 10499 - 10514
Publisher: IEEE
 
» Buffer-Layer Dependence of Interface Magnetic Anisotropy in Co2Fe0.4Mn0.6Si Heusler Alloy Ultrathin Films
Abstract:
Buffer-layer dependences of dead-layer thickness, saturation magnetization (, and interface magnetic anisotropy ( were systematically investigated for Co2Fe0.4Mn0.6Si (CFMS) Heusler alloy ultrathin films with Pd, Ru, and Cr buffer layers. Perpendicular magnetization was only achieved in 0.6 and 0.8 nm-thick CFMS ultrathin films deposited on Pd buffer layer and annealed at 400 °C. At the optimum annealing temperature of 400 °C, of 1.2 erg/cm2 was obtained for the Pd buffer layer, which was 3–6 times larger than those for Ru and Cr buffer layers. The difference in probably originates from the interdiffusion and different crystallized compounds at the interface between Pd (Ru, Cr) and CFMS layers.
Autors: Mingling Sun;Takahide Kubota;Yoshiaki Kawato;Shigeki Takahashi;Arata Tsukamoto;Yoshiaki Sonobe;Koki Takanashi;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Building a New World (On Top of Our Legs) [Editorial]
Abstract:
Autors: Cristian Quintero;
Appeared in: IEEE Potentials
Publication date: Nov 2017, volume: 36, issue:6, pages: 3 - 3
Publisher: IEEE
 
» Building NVRAM-Aware Swapping Through Code Migration in Mobile Devices
Abstract:
Mobile applications are becoming increasingly feature-rich and powerful, but also dependent on large main memories, which consume a large portion of system energy, especially for devices equipped with 4/6 GB DRAM. Swapping inactive DRAM pages to byte-addressable, non-volatile memory (NVRAM) is a promising solution to this problem. However, most NVRAMs have limited write endurance and the current victim pages selecting algorithm does not aware it. Therefore, to make it practical, the design of an NVRAM based swapping system must also consider endurance. In this paper, we target at prolonging the lifetime of NVRAM based swap area in mobile devices by reducing the write activities to NVRAM based swap area. Different from traditional wisdom, such as wear leveling and hot/cold data identification, we propose to build a system called nCode, which exploits the fact that code pages are easy to identify, read-only, and therefore a perfect candidate for swapping. Utilizing NVRAM’s byte-addressability, we support execute-in-place (XIP) of the code pages in the swap area, without copying them back to DRAM based main memory. Experimental results based on the Google Nexus 5 smartphone show that nCode can effectively prolong the lifetime of NVRAM under various workloads.
Autors: Kan Zhong;Duo Liu;Lingbo Long;Jinting Ren;Yang Li;Edwin Hsing-Mean Sha;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Nov 2017, volume: 28, issue:11, pages: 3089 - 3099
Publisher: IEEE
 
» Built-in-Self-Calibration for I/Q Imbalance in Wideband Millimeter-Wave Gigabit Transmitters
Abstract:
This paper addresses the estimation and compensation of I/Q imbalance, one of the most prominent impairments found in wideband zero-intermediate frequency transceivers (TRxs). The I/Q imbalance encountered in this kind of TRx comprises not only frequency-selective gain and phase imbalance but also delay imbalance. Unless appropriate compensation is applied, the I/Q imbalance significantly degrades the performance of a communication system. This paper presents a novel compensation technique for transmitter I/Q imbalance based on built-in-self-calibration, a low cost and robust compensation technique that enables manufacturing as well as in-field calibration with low computational complexity. The method’s performance is evaluated in a TRx with 64-quadratic-amplitude modulation and 2 GHz of bandwidth implemented with real hardware. The measurements show that the proposed technique achieves an image rejection ratio greater than 35 dB in the entire 2 GHz bandwidth and an error vector magnitude lower than 3%.
Autors: Ainhoa Rezola;Juan F. Sevillano;Iñaki Gurutzeaga;David del Rio;Roc Berenguer;Igone Vélez;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Nov 2017, volume: 65, issue:11, pages: 4758 - 4769
Publisher: IEEE
 
» Cache Placement in Fog-RANs: From Centralized to Distributed Algorithms
Abstract:
To deal with the rapid growth of high-speed and/or ultra-low latency data traffic for massive mobile users, fog radio access networks (Fog-RANs) have emerged as a promising architecture for next-generation wireless networks. In Fog-RANs, the edge nodes and user terminals possess storage, computation and communication functionalities to various degrees, which provide high flexibility for network operation, i.e., from fully centralized to fully distributed operation. In this paper, we study the cache placement problem in Fog-RANs, by taking into account flexible physical-layer transmission schemes and diverse content preferences of different users. We develop both centralized and distributed transmission aware cache placement strategies to minimize users’ average download delay subject to the storage capacity constraints. In the centralized mode, the cache placement problem is transformed into a matroid constrained submodular maximization problem, and an approximation algorithm is proposed to find a solution within a constant factor to the optimum. In the distributed mode, a belief propagation-based distributed algorithm is proposed to provide a suboptimal solution, with iterative updates at each BS based on locally collected information. Simulation results show that by exploiting caching and cooperation gains, the proposed transmission aware caching algorithms can greatly reduce the users’ average download delay.
Autors: Juan Liu;Bo Bai;Jun Zhang;Khaled B. Letaief;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Nov 2017, volume: 16, issue:11, pages: 7039 - 7051
Publisher: IEEE
 
» Calculating All Minimal Transition-Based Sensor Activation Policies for the Purpose of Supervisory Control
Abstract:
Consider the problem of designing a supervisory control in which the supervisor has control not merely over the inputs (or actuators), but can also choose to turn sensors on or off. In this context, the supervisor can flexibly adjust the set of activated sensors to reduce sensor utilization without compromising the correctness of control decisions. Building upon existing methods for computing a transition-based minimal sensor activation policy, algorithms are presented in this technical note for computing all minimal transition-based sensor activation policies. This result is then extended for minimizing the numerical sensor activation cost for systems modeled by stochastic automata.
Autors: Weilin Wang;Chaohui Gong;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Nov 2017, volume: 62, issue:11, pages: 5894 - 5901
Publisher: IEEE
 
» Calculation of Critical Oscillation Modes for Large Delayed Cyber-Physical Power System Using Pseudo-Spectral Discretization of Solution Operator
Abstract:
In eigenanalysis of large delayed cyber-physical power system (DCPPS), power engineers are interested in critical electromechanical oscillation modes with damping ratios less than a specified threshold. To efficiently compute these modes, a method based on pseudo-spectral discretization of the solution operator of DCPPS (SOD-PS) is presented in this paper. First, the unique spectral mapping properties of solution operator are analyzed. The largest eigenvalues in moduli of the operator correspond to the ones of DCPPS with the largest real parts. Second, a rotation-and-multiplication preconditioning technique is presented to enhance the dispersion among eigenvalues of the solution operator's discretized matrix. Third, critical electromechanical oscillation modes of DCPPS with the least damping ratios are captured with priority and an accelerated convergence rate by the implicitly restarted Arnoldi algorithm. Subsequently, the small signal stability of DCPPS can be readily and reliably determined. In SOD-PS, the unique property of Kronecker product and the inherent sparsity in augmented system matrices are fully exploited to guarantee efficiency and scalability. The accuracy and efficiency of the presented method are intensively studied and thoroughly validated on the 16-generator 68-bus test system and a real-life large transmission grid.
Autors: Hua Ye;Qianying Mou;Yutian Liu;
Appeared in: IEEE Transactions on Power Systems
Publication date: Nov 2017, volume: 32, issue:6, pages: 4464 - 4476
Publisher: IEEE
 
» Capacity of Social-Aware Wireless Networks With Directional Antennas
Abstract:
The widespread of smart phones has brought new social-aware features to wireless networks. Users prefer to forward traffic to their social contacts in social-aware networks, which is highly different from the traditional uniform traffic pattern. To this end, we analyze a social-aware wireless network, which is modeled by the social contacts between nodes, and explore its impact on network throughput capacity. We present that it can refine social contacts, thus improving the network capacity. Moreover, directional antennas are applied to further enhance the capacity performance, which can reduce the interference brought by other simultaneous communications. We derive the throughput capacity for social-aware networks with single-beam and multi-beam directional antenna, respectively. For single-beam directional antenna, we prove that when wireless networks are dominated by traffics of short-distance social contact, the throughput capacity can be promoted from order of to . In addition, when the beamwidth is at order of , the throughput capacity is a constant. Thus, the wireless network is scalable. For multi-beam antennas, we prove that when sidelobe gain is at order of , where is main lobe gain, compared with the single-beam case, the network capacity can achieve the order of .
Autors: Zhida Qin;Xiaoying Gan;Jingchao Wang;Luoyi Fu;Xinbing Wang;
Appeared in: IEEE Transactions on Communications
Publication date: Nov 2017, volume: 65, issue:11, pages: 4831 - 4844
Publisher: IEEE
 
» Carrier Frequency and DOA Estimation of Sub-Nyquist Sampling Multi-Band Sensor Signals
Abstract:
With the increase of signal bandwidth demands in these applications, it is a technical challenge to achieve the required high Nyquist sampling rate. In this paper, a new sub-Nyquist sampling array architecture for the multi-band signal carrier frequency and DOA estimation based on a uniform linear array is proposed, which consists of a two-stage estimate algorithm and the corresponding parameter pairing approach. We first adopt a sub-Nyquist sampling structure, namely, a modulated wideband converter (MWC), to sample the received signal at the reference sensor, and then the signal is reconstructed and the carrier frequencies are estimated accordingly. Second, the sub-Nyquist sampling data of other sensors are similarly obtained by using one channel of the MWC, respectively. In doing so, conventional DOA estimation algorithms can be adopted for the multi-band signals and a linearly correlated steering vector can be easily resolved. Furthermore, an effective pairing approach is also developed to match the multi-band signals in the estimated DOAs. The effectiveness of all the proposed methods is verified by simulation results.
Autors: Can Cui;Wen Wu;Wen-Qin Wang;
Appeared in: IEEE Sensors Journal
Publication date: Nov 2017, volume: 17, issue:22, pages: 7470 - 7478
Publisher: IEEE
 
» Cascaded Channel Model, Analysis, and Hybrid Decoding for Spin-Torque Transfer Magnetic Random Access Memory
Abstract:
Spin-torque transfer magnetic random access memory (STT-MRAM) is a promising non-volatile memory technology widely considered to replace dynamic random access memory (DRAM). However, there still exist critical technical challenges to be tackled. For example, process variation and thermal fluctuation may lead to both write errors and read errors, severely affecting the reliability of the memory array. In this paper, we first propose a novel cascaded channel model for STT-MRAM that facilitates fast error rate simulations and more importantly the theoretical design and analysis of memory sensing and channel coding schemes. We analyze the raw bit error rate and probabilities of dominant error events, and derive the maximum likelihood decision criterion and the log-likelihood ratio of the cascaded channel. Based on these works, we further propose a two-stage hybrid decoding algorithm for extended Hamming codes for STT-MRAM. Simulation results demonstrate the effectiveness of the proposed hybrid decoding algorithm for improving the reliability of STT-MRAM in the presence of both write errors and read errors and supporting its potential applications, such as replacing DRAM.
Autors: Kui Cai;Kees A. Schouhamer Immink;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 11
Publisher: IEEE
 
» Catheter Hydrophone Aberration Correction for Transcranial Histotripsy Treatment of Intracerebral Hemorrhage: Proof-of-Concept
Abstract:
Histotripsy is a minimally invasive ultrasound therapy that has shown rapid liquefaction of blood clots through human skullcaps in an in vitro intracerebral hemorrhage model. However, the efficiency of these treatments can be compromised if the skull-induced aberrations are uncorrected. We have developed a catheter hydrophone which can perform aberration correction (AC) and drain the liquefied clot following histotripsy treatment. Histotripsy pulses were delivered through an excised human skullcap using a 256-element, 500-kHz hemisphere array transducer with a 15-cm focal distance. A custom hydrophone was fabricated using a mm PZT-5h crystal interfaced to a coaxial cable and integrated into a drainage catheter. An AC algorithm was developed to correct the aberrations introduced between histotripsy pulses from each array element. An increase in focal pressure of up to 60% was achieved at the geometric focus and 27%–62% across a range of electronic steering locations. The sagittal and axial −6-dB beam widths decreased from 4.6 to 2.2 mm in the sagittal direction and 8 to 4.4 mm in the axial direction, compared to 1.5 and 3 mm in the absence of aberration. After performing AC, lesions with diameters ranging from 0.24 to 1.35 mm were generated using electronic steering over a mm grid in a tissue-mimicking phantom. An average volume of 4.07 ± 0.91 mL was liquefied and drained after using electronic steering to treat a 4.2-mL spherical volume in in vitro bovine clots through the skullcap.
Autors: Tyler Gerhardson;Jonathan R. Sukovich;Aditya S. Pandey;Timothy L. Hall;Charles A. Cain;Zhen Xu;
Appeared in: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Publication date: Nov 2017, volume: 64, issue:11, pages: 1684 - 1697
Publisher: IEEE
 
» Centralized Optimization for Dec-POMDPs Under the Expected Average Reward Criterion
Abstract:
In this paper, the decentralized partially observable Markov decision process (Dec-POMDP) systems with discrete state and action spaces are studied from a gradient point of view. Dec-POMDPs have recently emerged as a promising approach to optimizing multiagent decision making in the partially observable stochastic environment. However, the decentralized nature of the Dec-POMDP framework results in a lack of shared belief state, which makes the decision maker impossible to estimate the system state based on local information. In contrast to the belief-based policy, this paper focuses on optimizing the decentralized observation-based policy, which is easily to be applied and does not have the sharing problem. By analyzing the gradient of the objective function, we have developed a centralized stochastic gradient policy iteration algorithm to find the optimal policy on the basis of gradient estimates from a single sample path. This algorithm does not need any specific assumption and can be applied to most practical Dec-POMDP problems. One numerical example is provided to demonstrate the effectiveness of the algorithm.
Autors: Xiaofeng Jiang;Xiaodong Wang;Hongsheng Xi;Falin Liu;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Nov 2017, volume: 62, issue:11, pages: 6032 - 6038
Publisher: IEEE
 
» Ceramic Bearings for Electric Motors: Eliminating Damage with New Materials
Abstract:
Since the advent of variable frequency drive motors, standard rolling element bearings have been failing from electrical arcing because of stray electrical currents in the motors. This article will explore the damage mechanism in the bearings and introduce the use of ceramic rolling element bearings to eliminate this issue. Case histories will be provided.
Autors: James A. Oliver;Gustavo Guerrero;Josh Goldman;
Appeared in: IEEE Industry Applications Magazine
Publication date: Nov 2017, volume: 23, issue:6, pages: 14 - 20
Publisher: IEEE
 
» Challenges and Open Problems in Signal Processing: Panel Discussion Summary from ICASSP 2017 [Panel and Forum]
Abstract:
This column summarizes the panel on open problems in signal processing, which took place on 5 March 2017 at the International Conference on Acoustics, Speech, and Signal Processing (ICASSP) in New Orleans, Louisiana. The goal of the panel was to draw attention to some of the challenges and open problems in various areas of signal processing and generate discussion on future research areas that can be of major significance and impact in signal processing. Five leading experts representing diverse areas within signal processing made up the panel.
Autors: Yonina C. Eldar;Alfred O. Hero III;Li Deng;Jeff Fessler;Jelena Kovacevic;H. Vincent Poor;Steve Young;
Appeared in: IEEE Signal Processing Magazine
Publication date: Nov 2017, volume: 34, issue:6, pages: 8 - 23
Publisher: IEEE
 
» Chance-Constrained Economic Dispatch With Non-Gaussian Correlated Wind Power Uncertainty
Abstract:
Extending traditional deterministic economic dispatch to incorporate significant stochastic wind power is an important but challenging task in today's power system decision making. In this paper, this issue is formulated as a chance-constrained economic dispatch (CCED) problem. Usually, in the presence of non-Gaussian correlated random variables, both the objective function and constraints are difficult to handle. To address this issue, this paper provides a novel method dealing with non-Gaussian random variables. First, the Gaussian mixture model is adopted to represent the joint probability density function of power output for multiple wind farms. Then, analytical formulae are derived that can be used for fast computation of partial derivatives of the objective function and transformation of chance constraints into linear ones. Thereafter, the CCED can be solved as a deterministic linear convex optimization with a global optimal solution. The effectiveness and efficiency of the proposed methodology are validated via a case study with a modified IEEE 39-bus system.
Autors: Zhiwen Wang;Chen Shen;Feng Liu;Xiangyu Wu;Chen-Ching Liu;Feng Gao;
Appeared in: IEEE Transactions on Power Systems
Publication date: Nov 2017, volume: 32, issue:6, pages: 4880 - 4893
Publisher: IEEE
 
» Changes in the Editorial Board
Abstract:
After nine years (the maximum three consecutive terms) on the Editorial Board of the IEEE Transactions on Electron Devices (T-ED), Prof. David Esseni from the University of Udine, Prof. Jason Woo from the University of California at Los Angeles, and Prof. Ru Huang from Peking University have stepped down from their Editor positions in MOS Devices and Technology. I would like to express my sincere gratitude—and the gratitude of the Electron Device Society community at large—to David, Jason, and Ru for their commitment, dedication, and hard work during their term of service. Our very best wishes to them in their future endeavors.
Autors: Giovanni Ghione;Yogesh Singh Chauhan;Karol Kalna;Giovanni Verzellesi;Runsheng Wang;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Nov 2017, volume: 64, issue:11, pages: 4372 - 4373
Publisher: IEEE
 
» Channel Condition Aware Detection in Statistical Signal Transmission
Abstract:
Heterogeneous network (HetNet) plays an important role in the upcoming 5G communications. A HetNet in futuristic communications is envisaged to provide full access data services, such that users will always have the best service with their available radio resources. To realize a full access HetNet, statistical signal transmission (SST) can be an important enabling technique. SST exploits statistical features of ordinary signals as a data transmission scheme to carry information data. Due to its inherent unique properties, SST signal is more robust than ordinary signals in conventional quasi-static channels. However, detection of SST signals in fast time-varying channels will face challenges. Motivated by this fact, this paper aims to analyze the impact of fast time-varying channels to SST, and reveals negative effects of burst of deep fading channel-state (BDFC) and feature dissipation with out-of-phase (FDOP). Accordingly, we design an automatic re-transmission scheme and a fragmental feature capturing method to mitigate the aforementioned issues, respectively. Based on these studies, we propose a channel condition aware detection scheme for SST, aiming to enhance SST detection performance in fast time-varying channels. Numerical results show that with the proposed scheme, a maximum gain of more than 10 dB can be obtained under either BDFC or FDOP condition. Furthermore, it is also demonstrated that the proposed scheme is robust with imperfect channel coherence time information, which is attractive for practical applications.
Autors: Tianheng Xu;Mengying Zhang;Sha Yao;Honglin Hu;Hsiao-Hwa Chen;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Nov 2017, volume: 16, issue:11, pages: 7221 - 7234
Publisher: IEEE
 
» Channel Estimation for FDD Multi-User Massive MIMO: A Variational Bayesian Inference-Based Approach
Abstract:
This paper addresses downlink channel estimation for frequency division duplex multi-user massive multiple-input multiple-output systems. Suppose that a base station communicates with mobile users, then the task is to estimate channel matrices, each corresponding to one user. Due to the limited scattering in physical propagation, each channel matrix is sparse in the virtual angular domain. Besides, different user links tend to share some common scatterers. As such, different channel matrices may have a partially common sparsity pattern. These observations motivate us to take a variational Bayesian inference based approach for channel estimation. Specifically, we design a Gaussian mixture prior model, which can efficiently capture the individual sparsity in each channel matrix and the partially joint sparsity shared by different channel matrices. Furthermore, we develop a variational expectation maximization strategy to estimate the hyperparameters associated with the prior model and the channel matrices. Compared with the existing counterparts, the proposed approach achieves much better performance in terms of the channel estimation accuracy, while maintaining a low computational complexity.
Autors: Xiantao Cheng;Jingjing Sun;Shaoqian Li;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Nov 2017, volume: 16, issue:11, pages: 7590 - 7602
Publisher: IEEE
 
» Channel Probing in Opportunistic Communication Systems
Abstract:
We consider a multi-channel communication system in which a transmitter has access to channels, but does not know the state of any of the channels. We model the channel state using an ON/OFF Markov process, and allow the transmitter to probe a single channel at predetermined probing intervals to decide over which channel to transmit. For models in which the transmitter must transmit over the probed channel, it has been shown that a myopic policy probing the channel most likely to be ON is optimal. In this paper, we allow the transmitter to select a channel over which to transmit that is potentially different from the probed channel. For a system of two channels, we show that the choice of which channel to probe does not affect the throughput. For a system with many channels, we show that a probing policy that probes the channel that is the second-most likely to be ON results in higher throughput. We extend the channel probing problem to dynamically choose when to probe based on probing history, and characterize the optimal probing policy for various scenarios.
Autors: Matthew Johnston;Isaac Keslassy;Eytan Modiano;
Appeared in: IEEE Transactions on Information Theory
Publication date: Nov 2017, volume: 63, issue:11, pages: 7535 - 7552
Publisher: IEEE
 
» Channel Training for MIMO Relay Systems in the Presence of Interference
Abstract:
In this paper, we propose an optimal channel training method in the sense of linear minimum mean square error for multiple-input multiple-output amplify-and-forward relay systems in the presence of interference. By using a relay processing matrix, the received interference is cancelled or mitigated. To make the problem tractable, we first derive the optimal structure of the training signal and the relay processing matrix. Then, we propose an optimal channel training method. In order to reduce the complexity, we also propose an asymptotically optimal channel training method. Simulation results demonstrate that the two proposed methods outperform the conventional training signal design methods in terms of both the mean square error and in the bit error rate.
Autors: Chang-Jae Chun;Il-Min Kim;Dong-Woo Lim;Hyung-Myung Kim;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Nov 2017, volume: 66, issue:11, pages: 10601 - 10605
Publisher: IEEE
 
» Channel-Aware Resource Allocation for Energy-Efficient Cloud Radio Access Networks Under Outage Specifications
Abstract:
This paper investigates a cloud radio access network (C-RAN) architecture for future wireless network, which focuses on centralized processing for spatially distributed remote radio heads (RRHs). Our main goal is to promote an energy efficient C-RAN under the consideration of multiple access interference (MAI) and imperfect channel state information at the transmitter (CSIT) via outage-aware resource allocation. The closed-form expression of fading-induced outage probability for each transceiver pair will be established by analyzing the statistical property of signal-to-interference-plus-noise. In the course of finding feasible solutions to enhance energy efficiency, the optimization procedures named C-RAN-based energy efficient power allocation (CEEPA) and low-complexity CEEPA are proposed. As the number of RRHs grows to infinity, the deterministic equivalents of performance metrics can be derived by applying recent results from random matrix theorem, which lead to an efficient way to obtain the asymptotic-optimal resource allocation policy. Also, the regularized zero-forcing precoding technique is adopted to mitigate MAI and can tackle the impact of imperfect CSIT thanks to the derivation of deterministic equivalents. Numerical simulations show that the proposed resource allocation schemes can provide better energy efficiency and the accuracy of asymptotic expressions is also verified. Furthermore, the merit of a distributed antenna system is demonstrated through the comparison with centralized antenna system.
Autors: Pei-Rong Li;Kai-Ten Feng;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Nov 2017, volume: 16, issue:11, pages: 7389 - 7403
Publisher: IEEE
 
» Characteristic Analysis of Surface Permanent-Magnet Vernier Motor According to Pole Ratio and Winding Pole Number
Abstract:
This paper aims to analyze the characteristics of a surface permanent-magnet Vernier motor (SPMVM) according to the pole ratio among the rotor magnet pole pairs, stator teeth, and winding pole number. The SPMVM has the same operational principle as a magnetic gear, and it is operated using the space harmonics of the air-gap flux density due to the magnetomotive force and air-gap permeance. In this paper, first, the design parameters of the SPMVM are specified based on an analytical calculation of the air-gap magnetic flux density. Moreover, various combinations of the rotor magnet pole pairs and stator teeth number are made and compared according to the operational principle of a Vernier motor using a 2-D finite-element method.
Autors: Shi Hyoseok;Noboru Niguchi;Katsuhiro Hirata;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Characterization of Permanent Magnet Magnetization
Abstract:
The performances of electrical machines highly depend on the behavior of materials, such as steel, copper, and permanent magnet. This paper focuses on permanent magnets whose magnetization must be precisely known. Thus a non-destructive approach which includes a combination of experiments and inverse problem, using the magnetostatic moment method, is presented in order to determine the magnetization of the magnet. With a Hall sensor, a scan of the field around the sample is made. These measurements and a numerical approach allow us to deduce the sample magnetization. Studies of two samples illustrate the advantages of this method.
Autors: Laure Arbenz;Olivier Chadebec;Christophe Espanet;Youness Rtimi;Gilles Cauffet;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Characterization of the Interfacial Dzyaloshinskii–Moriya Interaction in Pt/Co2FeAl0.5Si0.5 Ultrathin Films by Brillouin Light Scattering
Abstract:
Brillouin light scattering (BLS) combined with vibrating sample magnetometry (VSM) have been used to investigate the Dzyaloshinskii–Moriya interaction (DMI) in Pt-buffered Co2FeAl0.5Si0.5 ultrathin films of various thicknesses. VSM measurements of the Co2FeAl0.5Si0.5 (CFAS) thickness dependence of the saturation magnetic moment per unit area revealed a magnetization at saturation of 1286 emu/cm3 and 0.31 nm magnetic dead layer. Furthermore, thickest films ( nm) are in-plane magnetized, while the thinner ones are perpendicular magnetized. BLS measurements, in the Damon–Eshbach geometry, under an in-plane applied magnetic field revealed the non-reciprocity of the spin waves (SWs) propagating in opposite directions (Stokes and anti-Stokes lines) due to the Pt-induced DMI. Stokes and anti-Stokes lines’ frequency mismatch varies linearly as function of the SW vector allowing the determination of the effective DMI constant. Its thickness dependence leads to determine a value of −0.42 pJ/m for the DMI interface constant, which is significantly lower than that of Pt/Co/AlOx films. Moreover, BLS measurements revealed that the effective magnetization varies linearly with the reciprocal effective CFAS thickness due to the perpendicular interface anisotropy, estimated to be 0.49 mJ/m2, which reinforces the perpendicular magnetization easy axis.
Autors: M. Belmeguenai;M. S. Gabor;Y. Roussigné;S. M. Chérif;A. Stashkevich;T. Petrisor;R. B. Mos;C. Tiusan;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Characterization of UHF Band LC Filter With RF Spiral Inductor Using Carbonyl-Iron Powder/Epoxy Composite Magnetic and Chip Capacitor
Abstract:
In order to realize the -factor increase scheme for a radio frequency (RF) spiral inductor used in the RF front/end circuit of smart phone handset, an introduction of carbonyl-iron powder (CIP)/epoxy composite magnetic core to air-core spiral inductor has been done. The composite magnetic core made by metal-mask printing consisted of mean diameter CIP and epoxy resin matrix. A two-turn copper spiral inductor with composite magnetic core filled only in spacing between conductor lines was fabricated. The -factor of the inductor with composite magnetic core is about 1.3 times higher than that of an air-core spiral inductor at around 0.7 GHz. An important effect of -factor increase by embedded composite magnetic core in the spacing between conductor lines is obtained. A main reason is that a proximity effect is suppressed in conductor line of the spiral coil. In addition, the simplest LC filter simulating RF circuit with the RF spiral inductor using the composite and a chip capacitor was fabricated and evaluated. The transmission coefficient of the composite magnetic core spiral inductor was about 0.9 times lower than that of the same size air-core spiral inductor. The filter characteristic of the composite core inductor was superior to that of the air-core inductor.
Autors: Makoto Sonehara;Sota Yamaguchi;Yuki Miyajima;Toshiro Sato;Takeshi Inomata;Yuji Ono;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Characterizing a Preclinical Magnetic Particle Imaging System With Separate Pickup Coil
Abstract:
Magnetic particle imaging (MPI) is an emerging technology with the potential for great impact on both medicine and biomedical research. Its optimization and acceptance are dependent upon a significant research effort in the development of tracer materials, data acquisition equipment, and image reconstruction techniques. We present initial results obtained from a prototype signal acquisition instrument designed to offer improvements to the sensitivity, and signal-to-noise ratio (SNR), of a preclinical MPI system (Bruker 25/20). We present the Fourier analysis of the signals detected using both the original data collection instrument provided with the MPI system, and the new prototype detector. By comparison of the spectra obtained, we show that the imaging signals from the prototype instrument are of greater intensity, and extend into higher frequencies, than those obtained using the original measurement instrument. We present image reconstructions of vascular phantoms containing tracer at concentrations between c(Fe) = 0.1 and 0.0125 mol/L. The improved sensitivity of the prototype detector allows the resolution of phantoms at tracer concentrations below those attainable using the original detector instrument. Finally, we quantify the improvement offered by the new detector based on a summation of the SNR values above a background threshold, within the frequency region of interest for MPI data acquisition. By plotting these totals at a variety of sample concentrations, we calculate a final receive gain (FRG) factor to describe the improvement offered by the new detector. For the prototype studied, we find FRG = 4.7 ± 0.6.
Autors: James Wells;Hendrik Paysen;Olaf Kosch;Norbert Löwa;Florian Schmitzberger;Marcus Makowksi;Jochen Franke;Lutz Trahms;Frank Wiekhorst;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Characterizing Angular Dependence of Spin-Orbit Torque Effective Fields in Pt/(Co/Ni)2/Co/IrMn Structure
Abstract:
We investigate the interplay between the spin-orbit torque (SOT)-induced effective fields and the azimuth angle of the magnetization vector with respect to the applied current. A method to quantify the ratio of the planar Hall effect to the anomalous Hall effect in perpendicular magnetic anisotropy (PMA) structures by using the low field harmonic Hall voltage measurement technique is devised. The validity of the ratio is confirmed by measuring the PMA effective field. In addition, a technique to characterize the SOT effective fields as a function of the magnetization vector azimuth angle with respect to the current direction is proposed and experimentally validated. The experimental results are in quantitative agreement with our derivations. Our measurement reveals that the field-like effective SOT fields are minima when the azimuth angle of magnetization with respect to the current is at 45°.
Autors: Christian Engel;Sarjoosing Goolaup;Feilong Luo;Wen Siang Lew;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Chirped-Pulse Phase-Sensitive Reflectometer Assisted by First-Order Raman Amplification
Abstract:
The use of linearly chirped probe pulses in phase-sensitive optical time-domain reflectometry (ΦOTDR) technology has been recently demonstrated to allow for high-resolution, quantitative, and dynamic temperature or strain variation measurements in a simple and very robust manner. This new sensing technology, known as chirped-pulse ΦOTDR, had a maximum reported sensing range of 11 km. In this paper, a 75-km sensing range with 10-m spatial resolution is demonstrated by using bidirectional first-order Raman amplification. The system is capable of performing truly linear, single-shot measurements of strain perturbations with an update rate of 1-kHz and 1-nε resolution. The time-domain trace of the sensor exhibits a signal-to-noise ratio (SNR) in the worst point of >3 dB, allowing to monitor vibrations up to 500 Hz with remarkable accuracy. To demonstrate the capabilities of the proposed system, we apply <;100 nε vibrations in the noisiest point of the fiber, with a frequency modulated from 70 to 150 Hz over a period of 10 s. The results obtained in these conditions demonstrate a vibration detection SNR of >20 dB (with only 300-ms analysis window and no postprocessing) and no evidence of nonlinearity in the acoustic response. The optical nonlinear effects that the probe pulse could suffer along the sensing fiber are thoroughly studied, paying special attention to potential distortions of the pulse shape, particularly in its instantaneous frequency profile. Our analysis reveals that, for proper values of peak power, the pulse does not suffer any major.
Autors: Juan Pastor-Graells;Javier Nuño;María Rosario Fernández-Ruiz;Andres Garcia-Ruiz;Hugo F. Martins;Sonia Martin-Lopez;Miguel Gonzalez-Herraez;
Appeared in: Journal of Lightwave Technology
Publication date: Nov 2017, volume: 35, issue:21, pages: 4677 - 4683
Publisher: IEEE
 
» CI Thermometer: Visualizing Confidence Intervals in Correlation Analysis
Abstract:
Correlation analysis is one of the most popular statistical methods. Despite that, the way research reports correlation is often misleading. The difficulty increases with the amount of information that must be read and interpreted. The proposed CI thermometer makes correlation matrices much easier to read and provides information that would be difficult to interpret when presented in another way.
Autors: Agnieszka Wnuk;Konrad J. Dębski;Marcin Kozak;
Appeared in: IEEE Computer Graphics and Applications
Publication date: Nov 2017, volume: 37, issue:6, pages: 103 - 108
Publisher: IEEE
 
» CIS Publication Spotlight [Publication Spotlight]
Abstract:
Presents a listing of books recently published in the field of computational intelligence.
Autors: Haibo He;Jon Garibaldi;Kay Chen Tan;Graham Kendall;Yaochu Jin;Yew-Soon Ong;
Appeared in: IEEE Computational Intelligence Magazine
Publication date: Nov 2017, volume: 12, issue:4, pages: 9 - 11
Publisher: IEEE
 
» CIS Publications in the Spotlight [President's Message]
Abstract:
Presents the President’s message for this issue of the publication.
Autors: Pablo A. Estevez;
Appeared in: IEEE Computational Intelligence Magazine
Publication date: Nov 2017, volume: 12, issue:4, pages: 4 - 13
Publisher: IEEE
 
» Clarifications on the Construction and Use of the ManyBugs Benchmark
Abstract:
High-quality research requires timely dissemination and the incorporation of feedback. Since the publication of the ManyBugs benchmark and its release on http://repairbenchmarks.cs.umass.edu/, researchers have provided feedback on the benchmark's construction and use. Here, we describe that feedback and our subsequent improvements to the ManyBugs benchmark.
Autors: Claire Le Goues;Yuriy Brun;Stephanie Forrest;Westley Weimer;
Appeared in: IEEE Transactions on Software Engineering
Publication date: Nov 2017, volume: 43, issue:11, pages: 1089 - 1090
Publisher: IEEE
 
» Closed-Form Approximations for Coverage Probability of Multistream MIMO-ZFBF Receivers in HetNets
Abstract:
The evaluation of the coverage probability of multistream multiple-input multiple-output (MIMO) communications in HetNets subject to noise, fading, and intercell interference is undoubtedly intricate. Unfortunately, the current literature misses its comprehensive evaluation, as the effects of noise and cross-stream correlation are often overlooked. Furthermore, computationally friendly expressions of the coverage probability allowing engineering insights and adaptive system design are lacking. For multistream MIMO zero-forcing beamforming, in this paper we tackle these issues by considering scenarios where a receiver is in the coverage if all of its data-streams are successfully decoded. Assuming the max signal-to-interference-plus-noise ratio (SINR) cell association (CA), we adopt the stochastic geometry tools to provide an upper bound and an easy-to-compute closed-form lower bound on the coverage probability, while their accuracies are confirmed against extensive simulations. Our contributions are as follows. We prove that full correlation of data streams of a given link slightly reduces the coverage performance. We show that from a coverage probability perspective, the single stream communication is preferable. We exploit our analysis to explore several pertinent design issues, which have not fully discussed in the literature. Our results demonstrate tradeoffs between densification and multiplexing gains. We, further, see that by appropriately designating feedback channel with modest capacity 8 bits per frame per user, the spatial throughput grows by nearly 180 over the conventional 1-bit feedback scenario. Finally, We present important extensions of our analysis to underlay spectrum sharing, practical aspects of the max-SINR CA, and a nonhomogeneous path loss environment.
Autors: Mohammad G. Khoshkholgh;Victor C. M. Leung;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Nov 2017, volume: 66, issue:11, pages: 9862 - 9879
Publisher: IEEE
 
» Closed-Form Expressions for ICI/ISI in Filtered OFDM Systems for Asynchronous 5G Uplink
Abstract:
One of the major purposes for fifth generation (5G) communications waveform design is to relax the synchronization requirements for supporting efficient massive machine type communications (MTCs). Polynomial cancellation coded orthogonal frequency-division multiplexing (PCC-OFDM) and universal filtered multi-carrier (UFMC) are designed to reduce the sidelobes of the OFDM waveform to protect against intercarrier interference (ICI) in the 5G uplink. To the best of our knowledge, there is no analysis of the effect of ICI for the UFMC system with time offset transmissions that many arise in MTC scenarios. Furthermore, there is no study on reducing the computational complexity of the UFMC system. This paper provides closed-form expressions for time offsets interference in such a case for OFDM, PCC-OFDM, and UFMC. This paper also presents theoretical analysis for the signal-to-interference-plus-noise ratio, achievable rate, and bit error ratio performance. The results show that PCC-OFDM significantly protects against ICI at the cost of halving the spectral efficiency. UFMC improves the ICI and intersymbol interference protection performance, especially when the length of time offset is very small, at the cost of significantly increasing the computational complexity. Finally, this paper proposes the overlap and adds UFMC and a variant of UFMC using infinite impulse response prototype filter banks to reduce the processing complexity.
Autors: Shendi Wang;John S. Thompson;Peter M. Grant;
Appeared in: IEEE Transactions on Communications
Publication date: Nov 2017, volume: 65, issue:11, pages: 4886 - 4898
Publisher: IEEE
 
» Cloth Animation Retrieval Using a Motion-Shape Signature
Abstract:
In cloth simulation, the behavior of textiles largely depends on initial conditions, parameters, and simulation techniques. Usually, several combinations of those aspects are altered until a simulation setting is found to create a satisfying animation. However, if an initial condition, such as a collision object, is changed afterward or the cloth behavior is transferred to a different scene, the existing set of simulation parameters could no longer be suitable for the desired look. In this case, it is difficult to find a new configuration by changing parameters manually and to determine if it conforms the desired properties. This article introduces a feature vector that is used as a motion-shape signature to capture the spatiotemporal shape characteristics of cloth and can be applied as a similarity measure for physics-based cloth animations.
Autors: Markus Huber;Bernhard Eberhardt;Daniel Weiskopf;
Appeared in: IEEE Computer Graphics and Applications
Publication date: Nov 2017, volume: 37, issue:6, pages: 52 - 64
Publisher: IEEE
 
» Clustering Effect on the Frequency-Dependent Magnetic Properties of Fe–Co Micro Hollow Fiber Composites
Abstract:
Composite sheets including Fe–Co magnetic hollow fibers are applicable to near-field electromagnetic wave absorption sheets operating in excess of 1 GHz. To understand the frequency-dependent permeability behavior of composite sheets, the Landau–Lifshitz–Gilbert equation and effective medium theory which are including the effects of the eddy current losses of isolated fibers and magnetostatic correction in high volume fractions can be used. However, the simulation considering only these factors requires a very high damping factor to explain the measured results. Thus, the simulation also needs the consideration of the clustering effect of particles causing the additional eddy current losses. In this paper, a new simulation method for magnetic sheets with clustered particles is proposed to improve an understanding of changes in the high-frequency properties of magnetic composite sheets due to the clustering effect.
Autors: Moosung Choi;Sounghun Lee;Jongryoul Kim;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Clutter Suppression via Hankel Rank Reduction for DFrFT-Based Vibrometry Applied to SAR
Abstract:
Hankel rank reduction (HRR) is a method that, by prearranging the data in a Hankel matrix and performing rank reduction via singular value decomposition, suppresses the noise of a time-history vector comprised of the superposition of a finite number of sinusoids. In this letter, the HRR method is studied for performing clutter suppression in synthetic aperture radar (SAR)-based vibrometry. Specifically, three different applications of the HRR method are presented. First, resembling the SAR slow-time signal model, the HRR method is utilized for separating a chirp signal immersed in a sinusoidal clutter. Second, using simulated airborne SAR data with 10 dB of signal-to-clutter ratio, the HRR method is applied to perform target isolation and to improve the results of an SAR-based vibration estimation algorithm. Finally, the vibrometry approach combined with the HRR method is validated using actual airborne SAR data.
Autors: Francisco Pérez;Balu Santhanam;Ralf Dunkel;Majeed M. Hayat;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Nov 2017, volume: 14, issue:11, pages: 2052 - 2056
Publisher: IEEE
 
» CMOS-Compatible Contacts to n-InP
Abstract:
In the context of the development of silicon photonics, various Ti- and Ni-based alloyed metallizations have been investigated for the purpose of forming low resistivity and Si CMOS-compatible contacts to n-InP. The innovative Ni2P metallization combined with an in situ Ar+ preclean represents the most suitable available solution for the formation of ohmic contacts with a specific contact resistivity as low as on such a semiconductor. The latter additionally presents the advantage of being stable at least up to 350 °C and could therefore withstand additional integration processes conducted at this temperature.
Autors: Elodie Ghegin;Philippe Rodriguez;Mattia Pasquali;Isabelle Sagnes;János L. Lábár;Vincent Delaye;Tiphaine Card;Jérémy Da Fonseca;Christophe Jany;Fabrice Nemouchi;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Nov 2017, volume: 64, issue:11, pages: 4408 - 4414
Publisher: IEEE
 
» Co-Optimization of Energy and Ancillary Services for Hydrothermal Operation Planning Under a General Security Criterion
Abstract:
One of the most used methods for long-term hydrothermal operation planning is the stochastic dual dynamic programming (SDDP). Using this method, the immediate and future water opportunity cost can be balanced and an economic-dispatch policy can be defined for multiple reservoirs under inflow uncertainty. In this framework, equipment outages and reserve deliverability are generally disregarded, despite their strong impact on the operative plan. However, recent advances in robust optimization have shown how to endogenously account for security criteria in scheduling models with reduced computational burden. Within this framework, reserve deliverability is ensured across the network via the co-optimization of energy and reserves (ancillary services). In this paper, we propose a new multistage model for planning hydrothermal coordination that co-optimizes the nominal energy dispatch and individual up and down reserve allocations. The main goal of this paper is to address a general security criterion, such that, for each inflow scenario, the system is capable of withstanding the loss of up to components, i.e., generation or transmission assets. The proposed methodology uses the column-and-constraint generation algorithm to efficiently incorporate a compound umbrella set of contingencies in the SDDP algorithm. Results for the Brazilian power system data corroborate the effectiveness of the proposed model.
Autors: Alexandre Street;Arthur Brigatto;Davi M. Valladão;
Appeared in: IEEE Transactions on Power Systems
Publication date: Nov 2017, volume: 32, issue:6, pages: 4914 - 4923
Publisher: IEEE
 
» Codebook Design for Beam Alignment in Millimeter Wave Communication Systems
Abstract:
Owing to abundant spectrum resources, millimeter wave (mmwave) communication promises to provide Gbps data rates, which, however, may be restricted by large path-loss. Thus, antenna arrays are commonly used along with beam alignment (BA) as an important step to achieve the array gain. Efficient BA relies on the beam training codebook design. In this paper, we propose a new hierarchical codebook to achieve uniform BA performance with low overhead. To better elaborate on the design principle, a single-path channel model is considered first to frame the proposal. The codebook design is formulated as an optimization problem, where the ripple in the main/side lobes is constrained such that each training beam is close to the ideal one with a flat magnitude response and a narrow transition band. Then, we propose an efficient algorithm to find such a beam training codebook. Furthermore, we derive closed-form expressions of the BA misalignment probability or error rate of the proposed beam training codebook. Our results reveal that using the proposed codebook, the error rate of tree-search-based BA exponentially decreases with the SNR for a given channel, and linearly decreases in the log–log coordinate axis for a fading channel. We further propose a power allocation scheme used in different training stages to further improve the BA performance. Finally, the proposed framework is extended to the more complex case of multi-path channels. Numerical results confirm the effectiveness of the proposed training codebook and power allocation scheme as well as the accuracy of the performance analysis.
Autors: Jianjun Zhang;Yongming Huang;Qingjiang Shi;Jiaheng Wang;Luxi Yang;
Appeared in: IEEE Transactions on Communications
Publication date: Nov 2017, volume: 65, issue:11, pages: 4980 - 4995
Publisher: IEEE
 
» Coded Slotted ALOHA for Erasure Channels: Design and Throughput Analysis
Abstract:
In this paper, we investigate the design and analysis of coded slotted ALOHA (CSA) schemes in the presence of channel erasure. We design the code probability distributions for CSA schemes with repetition codes and maximum distance separable codes to maximize the expected traffic load, under both packet erasure channels and slot erasure channels. We derive the extrinsic information transfer (EXIT) functions of CSA schemes over erasure channels. By optimizing the convergence behavior of the derived EXIT functions, the code probability distributions to achieve the maximum expected traffic load are obtained. Then, we derive the asymptotic throughput of CSA schemes over erasure channels. In addition, we validate that the asymptotic throughput can give a good approximation to the throughput of CSA schemes over erasure channels.
Autors: Zhuo Sun;Yixuan Xie;Jinhong Yuan;Tao Yang;
Appeared in: IEEE Transactions on Communications
Publication date: Nov 2017, volume: 65, issue:11, pages: 4817 - 4830
Publisher: IEEE
 
» Coexistence of Wi-Fi and LAA Networks With Adaptive Energy Detection
Abstract:
Licensed-assisted access (LAA) of the long term evolution (LTE) has been standardized by the Third Generation Partnership Project (3GPP) in Release 13 to address the urgent issues of ever-increasing traffic demands in cellular systems. However, challenges arise for the efficient coexistence of Wi-Fi and LAA in the same unlicensed spectrum. In this paper, the impact of LAA's energy detection thresholds on such coexistence are investigated from the perspective of collisions occurring during downlink transmissions. To facilitate the efficient coexistence of Wi-Fi and LAA, a distributed algorithm is proposed to adaptively change the energy detection thresholds of LAA per user or per base station, so that the system encourages more concurrent transmissions without introducing too many collisions. Simulation results validate the effectiveness of the proposed adaptive algorithm.
Autors: Li Li;James P. Seymour;Leonard J. Cimini;Chien-Chung Shen;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Nov 2017, volume: 66, issue:11, pages: 10384 - 10393
Publisher: IEEE
 
» Cogging Torque and Unbalanced Magnetic Force Prediction in PM Machines With Axial-Varying Eccentricity by Superposition Method
Abstract:
This paper proposes a double superposition method to quickly and accurately predict the cogging torque and unbalanced magnetic force (UMF) of permanent magnet machines with axial-varying rotor eccentricities. The original axial-varying eccentric machine is cut into several uniform slices along the axial direction and each slice is considered to be axially uniform, i.e., axial even. For each axial-even eccentric machine slice, the circumferential superposition method can be used to predict the cogging torque and UMF of this slice. Finally, the cogging torque and UMF of the original axial-varying eccentric machine can be obtained by using an axial superposition technique which combines the cogging torque and UMF of each slice with different eccentricity magnitudes together. The 3-D finite-element analysis is adopted to validate the efficacy of the proposed method and the merit of high accuracy and computational efficiency is also identified by comparing the results predicted from these two methods.
Autors: Y. X. Li;Z. Q. Zhu;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Cogging Torque Reduction by Elementary-Cogging-Unit Shift for Permanent Magnet Machines
Abstract:
This paper describes a method to reduce cogging torque in permanent magnet (PM) machines by shifting elementary-cogging unit (ECU). The ECU division principle and the feature of cogging torque produced by ECU are also discussed. The proper shift angles for each ECU are deduced according to both fractional and integral slot number per pole, by which any order harmonic cogging torque could be eliminated without the introduction of any new harmonic torque. This paper investigates the validity of the effectiveness of ECU shifting techniques using PM machines with different match of slot number per pole in 2-D finite-element models.
Autors: Jian Gao;Guang Wang;Xiao Liu;Wenjuan Zhang;Shoudao Huang;Huimin Li;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Colossal Positive Magnetoresistance in Oxygen-Deficient Ca4Mn3O10
Abstract:
Huge changes in resistance induced by an external magnetic field, i.e., a colossal magnetoresistance effect, is a long-lived theme of the research due to both fundamental science and device applications. Careful analysis of oxygen-deficient Ca4Mn3O10, synthesized by the citric acid method, establishes a direct correlation between magnetic and electric properties. An electric resistive anomaly at the magnetic ordering temperature of ~115 K supports this correlation. We currently report on a colossal positive magnetoresistance up to ~1300% below the metal-to-insulator transition temperature for oxygen-deficient Ca4Mn3O10. The positive magnetoresistance effect in this system may be attributed to the field-induced carrier localization.
Autors: Manimuthu Periyasamy;Anja Olafsen Sjåstad;Helmer Fjellvåg;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Comments on “A Cross-Layer Approach to Privacy-Preserving Authentication in WAVE-Enabled VANETs” by Biswas and Mišić
Abstract:
A WAVE-based cross-layer anonymous authentication scheme based on a variant of ECDSA (Biswas and Mišić “A Cross-layer approach to privacy-preserving authentication in WAVE-enabled VANETs,” IEEE Trans. Veh. Technol., vol. 62, no. 5, pp. 2182–2192, Jun. 2013.) was published for authenticity of vehicular safety application messages. Our result shows that, contrary to what is claimed, the scheme is entirely broken due to the insecurity of their underlying signature scheme: Their modification of ECDSA is insecure against secret key recovery attacks where anyone can recover OBUs’ or mobile nodes’ private keys from transmitted signed messages just eavesdropping.
Autors: Kyung-Ah Shim;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Nov 2017, volume: 66, issue:11, pages: 10588 - 10589
Publisher: IEEE
 
» Comments on “A General and Transformable Model Platform for Emerging Multi-Gate MOSFETs”
Abstract:
Hong et al. [1] presented an analytical solution for the electrostatic potential in undoped cylindrical MOSFETs, which was then employed within a well-known Pao-Sah integral to yield the device current. This same analytical solution and drain current calculation were presented in 2016 [2], but such work was not referenced by Hong et al. [1].
Autors: Giovanni M. Paolucci;Alessandro S. Spinelli;Christian Monzio Compagnoni;Paolo Tessariol;
Appeared in: IEEE Electron Device Letters
Publication date: Nov 2017, volume: 38, issue:11, pages: 1618 - 1618
Publisher: IEEE
 
» Comments on “Microstrip T-Junction Power Divider With Exponentially Tapered Transmission Lines”
Abstract:
In the above paper, Smith and Sigmarsson [1] proposed a T-junction unequal power divider using exponentially tapered transmission line (ENTL) and uniform transmission line (UTL). However, the cutoff wavelength defined in [1] and also in [2], from which the definition of has been adopted, are incorrect. So the entire analysis and design equations of [1] are questionable. Also, the authors have not shown the amplitude and phase imbalance variation over the frequency.
Autors: Rakesh Sinha;Ranadhir Chatterjee;Hungsun Son;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Nov 2017, volume: 27, issue:11, pages: 1037 - 1038
Publisher: IEEE
 
» Comments on ScottKnottESD in Response to “An Empirical Comparison of Model Validation Techniques for Defect Prediction Models”
Abstract:
In this article, we discuss the ScottKnottESD test, which was proposed in a recent paper “An Empirical Comparison of Model Validation Techniques for Defect Prediction Models” that was published in this journal. We discuss the implications and the empirical impact of the proposed normality correction of ScottKnottESD and come to the conclusion that this correction does not necessarily lead to the fulfillment of the assumptions of the original Scott-Knott test and may cause problems with the statistical analysis.
Autors: Steffen Herbold;
Appeared in: IEEE Transactions on Software Engineering
Publication date: Nov 2017, volume: 43, issue:11, pages: 1091 - 1094
Publisher: IEEE
 
» Comments on the Proof of Adaptive Stochastic Set Cover Based on Adaptive Submodularity and Its Implications for the Group Identification Problem in “Group-Based Active Query Selection for Rapid Diagnosis in Time-Critical Situations”
Abstract:
We point out an issue with one of the results in Bellala et al. [1] that invokes a main result on adaptive stochastic minimum cost cover problem (Theorem 5.8) of Golovin and Krause. We construct an example that shows that the proof of Theorem 5.8 of Golovin and Krause is invalid, and therefore, the proof in Bellala et al. about the near-optimum performance of their algorithm is also invalid.
Autors: Feng Nan;Venkatesh Saligrama;
Appeared in: IEEE Transactions on Information Theory
Publication date: Nov 2017, volume: 63, issue:11, pages: 7612 - 7614
Publisher: IEEE
 
» Common Learning Objectives for Undergraduate Control Systems Laboratories
Abstract:
Course objectives, like research objectives and product requirements, help provide clarity and direction for faculty and students. Unfortunately, course and laboratory objectives are not always clearly stated. Without a clear set of objectives, it can be hard to design a learning experience and determine whether students are achieving the intended outcomes of the course or laboratory. In this paper, a common set of laboratory objectives, concepts, and components of a laboratory apparatus for undergraduate control systems laboratories were identified. A panel of 40 control systems faculty members completed a multi-round Delphi survey to bring them toward consensus on the common aspects of their laboratories. These panelists identified 15 laboratory objectives, 26 concepts, and 15 components common to their laboratories. Then an 45 additional faculty members and practitioners completed a follow-up survey to gather feedback on the results. In both surveys, each participant rated the importance of each item. While average ratings differed slightly between the two groups, the order in which the items were ranked was similar. Important examples of common learning objectives include connecting theory to what is implemented in the laboratory, designing controllers, and modeling systems. The most common component in both groups was MathWorks software. Some of the common concepts include block diagrams, stability, and PID control. Defining common aspects of undergraduate control systems laboratories enables common development, detailed comparisons, and simplified adaptation of equipment and experiments between campuses and programs.
Autors: Rebecca M. Reck;
Appeared in: IEEE Transactions on Education
Publication date: Nov 2017, volume: 60, issue:4, pages: 257 - 264
Publisher: IEEE
 
» Communication in the Presence of a State-Aware Adversary
Abstract:
We study communication systems over the state-dependent channels in the presence of a malicious state-aware jamming adversary. The channel has a memoryless state with an underlying distribution. The adversary introduces a jamming signal into the channel. The message and the entire state sequence are known non-causally to both the encoder and the adversary. This state-aware adversary may choose an arbitrary jamming vector depending on the message and the state vector. Taking an arbitrarily varying channel (AVC) approach, we consider two setups, namely, the discrete memoryless Gel’fand–Pinsker AVC and the additive white Gaussian dirty paper (DP) AVC. We determine the randomized coding capacity of both the AVCs under a maximum probability of error criterion. Similar to other randomized coding setups, we show that the capacity is the same even under the average probability of error criterion. Though the adversary can choose an arbitrary vector jamming strategy, we prove that the adversary cannot affect the rate any worse than when it employs a memoryless strategy, which depends only on the instantaneous state. Thus, the AVC capacity characterization is given in terms of the capacity of the worst memoryless channels with state, induced by the adversary employing such memoryless jamming strategies. For the DP-AVC, it is further shown that among memoryless jamming strategies, none impact the communication more than a memoryless Gaussian jamming strategy which completely disregards the knowledge of the state. Thus, the capacity of the DP-AVC equals that of a standard additive white Gaussian noise (AWGN) channel with two independent sources of AWGN, i.e., the channel noise and the jamming noise.
Autors: Amitalok J. Budkuley;Bikash Kumar Dey;Vinod M. Prabhakaran;
Appeared in: IEEE Transactions on Information Theory
Publication date: Nov 2017, volume: 63, issue:11, pages: 7396 - 7419
Publisher: IEEE
 
» Compact Hash Codes for Efficient Visual Descriptors Retrieval in Large Scale Databases
Abstract:
In this paper, we present an efficient method for visual descriptors retrieval based on compact hash codes computed using a multiple k-means assignment. The method has been applied to the problem of approximate nearest neighbor (ANN) search of local and global visual content descriptors, and it has been tested on different datasets: three large scale standard datasets of engineered features of up to one billion descriptors (BIGANN) and, supported by recent progress in convolutional neural networks (CNNs), on CIFAR-10, MNIST, INRIA Holidays, Oxford 5K, and Paris 6K datasets; also, the recent DEEP1B dataset, composed by one billion CNN-based features, has been used. Experimental results show that, despite its simplicity, the proposed method obtains a very high performance that makes it superior to more complex state-of-the-art methods.
Autors: Simone Ercoli;Marco Bertini;Alberto Del Bimbo;
Appeared in: IEEE Transactions on Multimedia
Publication date: Nov 2017, volume: 19, issue:11, pages: 2521 - 2532
Publisher: IEEE
 
» Compact High-Isolation LTCC Diplexer Using Common Stub-Loaded Resonator With Controllable Frequencies and Bandwidths
Abstract:
In this paper, a low-temperature co-fired ceramic (LTCC) diplexer is presented with compact size and high isolation. By using the common stub-loaded resonator shared by two channel filters, combining and matching networks are eliminated and only three resonators are used to design the two second-order channel filters, resulting in simple structure and miniaturized size. A novel transmission path is utilized to not only realize the higher channel filter but also prevent the signal at the lower frequency band. And a specific coupling region is selected to simultaneously realize the coupling strength required by lower channel filter and a transmission zero at higher-band frequency. In this way, each channel filter can generate a transmission zero at the passband frequency of the other channel filter, resulting in high isolation. Moreover, the bandwidths and center frequencies of the two channel filters can be individually controlled due to the design flexibility of the multilayer LTCC structure. For demonstration, a diplexer operating at 3.5 and 5.5 GHz is fabricated. The core circuit has the compact size of 1.9 mm mm mm or . Within the 3-dB passbands of the lower and higher channel filters, the measured isolation levels are better than 40 and 45 dB, respectively.
Autors: Jin-Xu Xu;Xiu Yin Zhang;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Nov 2017, volume: 65, issue:11, pages: 4636 - 4644
Publisher: IEEE
 
» Comparative Analysis and Optimization of Dynamic Charging Coils for Roadway-Powered Electric Vehicles
Abstract:
Roadway-powering systems can effectively improve the driving distance of electric vehicles (EVs) while releasing the overdependence on batteries. As the key technical issue, the design of primary and pickup coils determines the dynamic charging performance. In recent years, the double-D-quadrature (DDQ) pickup coil has been increasingly utilized in EV dynamic charging systems by means of the persistence and stability of move-and-charge. However, the impact of primary coils with various topologies on DDQ pickup coils has been nearly unexplored in previous studies. Accordingly, this paper presents a comparative analysis of the circular-shaped, rectangle-shaped and multi-thread primary coils for DDQ-based roadway-powering systems with an emphasis on the transmission power, energization persistence, thermal analysis, and initial investment that aims to provide technical references for further research and development of EV dynamic wireless charging systems.
Autors: Zhen Zhang;Hongliang Pang;Christopher H. T. Lee;Xiangkui Xu;Xile Wei;Jiang Wang;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 6
Publisher: IEEE
 
» Comparative Analysis of Temporal Decorrelation at P-Band and Low L-Band Frequencies Using a Tower-Based Scatterometer Over a Tropical Forest
Abstract:
Temporal decorrelation is a critical parameter for repeat-pass coherent radar processing, including many advanced techniques such as polarimetric SAR interferometry (PolInSAR) and SAR tomography (TomoSAR). Given the multifactorial and unpredictable causes of temporal decorrelation, statistical analysis of long time series of measurements from tower-based scatterometers is the most appropriate method for characterizing how rapidly a specific scene decorrelates. Based on the TropiScat experiment that occurred in a tropical dense forest in French Guiana, this letter proposes a comparative analysis between temporal decorrelation at P-band and at higher frequencies in the range of 800–1000 MHz (the low end of the L-band). This letter aims to support the design of future repeat-pass spaceborne missions and to offer a better understanding of the physics behind temporal decorrelation. Beyond the expected lower values that are found and quantified at the low L-band compared with the P-band, similar decorrelation patterns related to rainy and dry periods are emphasized in addition to the critical impacts of acquisition time during the day.
Autors: A. Hamadi;L. Villard;P. Borderies;C. Albinet;T. Koleck;T. Le Toan;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Nov 2017, volume: 14, issue:11, pages: 1918 - 1922
Publisher: IEEE
 
» Comparative Study of E-Core and C-Core Modular PM Linear Machines With Different Slot/Pole Combinations
Abstract:
Four modular permanent magnet linear machines (PMLMs) with E-core and C-core primary segments and 12-slot/13-pole (12s/13p) and 12-slot/14-pole (12s/14p) slot/pole combinations are compared in this paper. The influences of flux gap width on the electromagnetic performances and power losses have been investigated based on 2-D finite-element modeling. It has been found that, by choosing proper flux gap width, not only the average thrust force can be improved but also the force ripple and iron losses can be reduced for all the machines. Also, the E-core modular PMLM has higher thrust force and lower detent force compared with the C-core modular PMLM with respect to the same slot/pole combination. Moreover, the 12s/13p modular PMLMs can achieve better electromagnetic performances than the 12s/14p ones regardless of E-core or C-core primary structures. Finally, by shaping the end teeth, the detent force and force ripple of the four modular PMLMs are further mitigated. The 12s/13p E-core modular PMLM is proven to be the best type among these four modular machines.
Autors: Yihua Yao;Qinfen Lu;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 7
Publisher: IEEE
 
» Comparative Study of Microfabricated Inductors/Transformers for High-Frequency Power Applications
Abstract:
This paper presents a comparative study on different microfabricated inductors (microtransformers), which are suitable for high-frequency power application. The main topic of this study is comparing and analyzing the effect of some factors such as material type, number of turns, and coil form on microinductor performance considering a fixed chip size, fixed magnetic core size, and core form. Two different microtransformer designs with different magnetic core materials are considered in this work. The core materials used in this work are NiFe45/55 and CoFe45/55. Also, two types of device packages are developed, namely, Quad Flat No-Lead and FR4 embedded packages. For device testing, different high-frequency switching regulators available on the market are used. This study shows the influence of different parameters on the performance of a certain high-frequency application. In this paper, we discuss the influence of the design, magnetic material, and package type on thermal performance and the efficiency of the power application.
Autors: Dragan Dinulovic;Mahmoud Shousha;Martin Haug;Sebastian Beringer;Marc C. Wurz;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 7
Publisher: IEEE
 
» Comparative Study of PM-Assisted SynRM and IPMSM on Constant Power Speed Range for EV Applications
Abstract:
This paper analyzes and compares the performances of permanent-magnet-assisted synchronous reluctance machines (PMa-SynRMs) and interior permanent magnet synchronous machine (IPMSM) on their constant power speed range (CPSR) capability for electric vehicle (EV) applications. The recent trend of less rare-earth magnet makes the IPMSM unfavorable despite its excellent CPSR. As an alternative, the PMa-SynRM possesses a higher saliency with lower PM quantity. The two different rotor designs would affect the CPSR and these need to be investigated and compared. As a key performance index for EV traction motors, the CPSR calculated by analytical methods often suffers low accuracy due to omission of saturation. Finite-element analysis (FEA) can be used to obtain the CPSR but significant computation time is required. This would be disadvantageous for accurate performance prediction in design stage. To resolve these problems, six 10 kW, 30 Nm/L designs are studied and compared, covering IPMSMs and PMa-SynRMs. An approach associating analytical methods with FEA is developed for accurate and rapid calculation of CPSR for these machines. A discussion on PMa-SynRM rotor designs and suggestion for their PM quantity are provided considering performance, cost, and demagnetization. Two prototypes were tested, one being IPMSM and the other PMa-SynRM to validate the analysis.
Autors: Thanh Anh Huynh;Min-Fu Hsieh;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 6
Publisher: IEEE
 
» Comparison of Axial Flux Permanent Magnet Synchronous Machines With Electrical Steel Core and Soft Magnetic Composite Core
Abstract:
This paper presents a comparison of axial flux permanent magnet machines (AFPMs) with an electrical steel core and that with a soft magnetic composite (SMC) core. SMCs have several advantages such as low core loss and low eddy current loss. However, compared with electrical steel, SMCs have poor magnetic properties such as low flux density saturation and unsaturated relative permeability. The analysis of the electromagnetic characteristics in a wide frequency range revealed that for an AFPM using an electric steel core, the performance was excellent in a low-frequency range; however, for an AFPM using an SMC core, the performance improves with an increase in frequency. Finally, the operation area of an AFPM using an SMC core is proposed.
Autors: Chang-Woo Kim;Gang-Hyeon Jang;Jeong-Man Kim;Ji-Hun Ahn;Chan-Ho Baek;Jang-Young Choi;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Comparison of Limiting Loop Model and Elemental Operator Model for Magnetic Hysteresis of Ferromagnetic Materials
Abstract:
This paper introduces a comparative study of two different hysteresis models, limiting loop model and elemental operator model. The former is regarded as a mathematical approach based on the traditional Preisach model. To circumvent the difficulty of determining the distribution function in the Preisach model, the data of the limiting hysteresis loop and a function transform on the Preisach diagram are employed. The latter is a physical method which adopts a vectorial elemental operator with biaxial anisotropy based on the magnetization mechanisms of the ferromagnetic material. These two models are analyzed and compared in terms of the underlying principle, numerical implementation, and calculation accuracy in this paper. To verify the introduced models, the magnetic properties of non-oriented silicon steel Lycore-140 and soft magnetic composite material Somaloy 500 under alternating excitations are measured and compared with simulated results, which show the validity and practicability of the models but with different calculation accuracy and speed.
Autors: Nana Duan;Weijie Xu;Yongjian Li;Shuhong Wang;Youguang Guo;Jianguo Zhu;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Comparison of the Linear and Spanwise-Segmented DBD Plasma Actuators on Flow Control Around a NACA0015 Airfoil
Abstract:
In this paper, linear and spanwise-segmented plasma actuator implementations as well as base airfoil with no plasma cases are presented. These approaches are used to control the flow around a NACA0015 airfoil. The experiments were conducted in a wind tunnel at Reynolds number of . The plasma actuators mounted on the leading edge of the airfoil at chord position of 0.1 (). The electrical parameters used for the plasma generating device are set to constant values of 6-kVpp applied voltage and 3.5-kHz excitation frequency. It is observed that the use of spanwise-segmented plasma actuators converts the 2-D flow structure around the airfoil into 3-D forcing flow structure. The change of the wake region width of the airfoil is visualized by using the smoke-wire method. The flow visualization is performed at attack angles of 0°, 5°, 10°, and 15°. In addition, necessary measurements are also made to determine drag and lift forces. A comparative study on the drag and lift forces for the NACA0015 airfoil is performed. As a part of the conclusions, linear and spanwise-segmented plasma actuator implementations as well as base airfoil with no plasma cases are compared and related results on flow control are presented.
Autors: Hürrem Akbıyık;Hakan Yavuz;Yahya Erkan Akansu;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Nov 2017, volume: 45, issue:11, pages: 2913 - 2921
Publisher: IEEE
 
» Comparison on the Coercivity Enhancement of Hot-Deformed Nd2Fe14B-Type Magnets by Doping R70Cu30 (R = Nd, Dy, and Tb) Alloy Powders
Abstract:
Coercivity enhancement effect of the anisotropic hot-deformed NdFeB magnets made from NdFeB MQU-F powders doped with 2 wt% low-melting R70Cu30 (R = Nd, Dy, and Tb) powders was explored. Post-annealing treatment at 600 °C and 700 °C was employed to modify the microstructures and therefore improve the magnetic properties of the hot-deformed magnets. Doping R70Cu30 alloy powders into the hot-deformed NdFeB magnets is effective in enhancing the coercivity from 15.1 kOe to 16.3–23.6 kOe, depending on the rare-earth elements adopted. The coercivity increment is 1.2 and 4.4 kOe for the magnets doped with Nd70Cu30 and Dy70Cu30 alloy powders, respectively. Most interestingly, Tb70Cu30-doped magnet followed with 700 °C post-annealing exhibits the highest coercivity iHc of 23.6 kOe and the highest coercivity increment of 8.5 kOe. TEM analysis shows that annealing treatment not only modifies the grain boundary of the platelet 2:14:1 phase but also promotes more Tb atoms entering into 2:14:1 crystal. As a result, the coercivity of the magnets is effectively enhanced.
Autors: Y. I. Lee;H. W. Chang;G. Y. Huang;C. W. Shih;W. C. Chang;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Complex Neuromuscular Changes Post-Stroke Revealed by Clustering Index Analysis of Surface Electromyogram
Abstract:
The objective of this paperwas to characterize complex neuromuscular changes induced by a hemisphere stroke through a novel clustering index (CI) analysis of surface electromyogram (EMG). The CI analysis was performed using surface EMG signals collected bilaterally from the thenar muscles of 17 subjects with stroke and 12 age-matched healthy controls during their performance of varying levels of isometric muscle contractions. Compared with the neurologically intact or contralateral muscles, mixed CI patterns were observed in the paretic muscles. Two paretic muscles showed significantly increased CI implying dominant neurogenic changes, whereas three paretic muscles had significantly reduced CI indicating dominantmyopathic changes; the other paretic muscles did not demonstrate a significant CI alternation, likely due to a deficit of descending central drive or a combined effect of neuromuscular factors. Such discrimination of paretic muscles was further highlighted using a modified CI method that emphasizes between-side comparison for each individual subject. The CI findings suggest that there appears to be different central and peripheral processes at work in varying degrees after stroke. This paper provides a convenient and quantitative analysis to assess the nature of neuromuscular changes after stroke, without using any special equipment but conventional surface EMG recording. Such assessment is helpful for the development of appropriate rehabilitation strategies for recovery of motor function.
Autors: Xu Zhang;Zhongqing Wei;Xiaoting Ren;Xiaoping Gao;Xiang Chen;Ping Zhou;
Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Publication date: Nov 2017, volume: 25, issue:11, pages: 2105 - 2112
Publisher: IEEE
 
» Composite Media for Heat Assisted Magnetic Recording
Abstract:
Composite media grains consisting of two discrete magnetic layers with different uniaxial anisotropies, , and Curie temperatures, , were investigated for heat assisted magnetic recording. The maximum switching probability of optimized composite grains exceeded that of single phase grains. As of one layer increased the optimum of the other layer became smaller, tending toward zero in many cases. Leading and trailing edge recording were also compared. Trailing edge recording was superior when the maximum temperature in the grain, , was similar to , but when exceeded leading edge recording performed better.
Autors: Simon John Greaves;Yoshiaki Sonobe;Hiroaki Muraoka;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Comprehensive Modeling to Allow Informed Calculation of DC Traction Systems’ Stray Current Levels
Abstract:
This study is directed toward furnishing stray current modeling on dc traction systems to cope with the variability of a number of influencing parameters. To this end, the archival value of this study is gained by virtue of two new modeling techniques. These new techniques, first, include a Monte—Carlo-based approach to take into account the variability of the dominant factors influencing the conductance per unit length between the track and the earth. Second, a simulation technique that can provide a more robust representation of the conductance per unit length between the track and the earth coupled with uniform and non-uniform soil models is presented in an attempt to comprehensively assess the levels of stray currents leaving a floating dc traction system.
Autors: Charalambos A. Charalambous;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Nov 2017, volume: 66, issue:11, pages: 9667 - 9677
Publisher: IEEE
 
» Compressed Dipoles Resonating at Higher Order Modes With Enhanced Directivity
Abstract:
A compressed dipole operating at higher order modes is proposed and investigated for the enhancement of boresight directivity. Compared with conventional dipoles in free space, the length of the proposed dipole is compressed although the currents on the compressed dipole still sinusoidally distribute. The traces of calculated compressed dipole’s directivity against compressibility show that the directivity of a compressed dipole operating at higher resonant modes is larger than conventional dipoles for the well selected compressibility. This paper shows that printing the dipole onto a piece of dielectric substrate can achieve the desired compressibility. The relationship between the compressibility and relative permittivity of the dielectric slab provides the guidance to realize the selected compressibility. As an example, a thin linear compressed dipole resonating at the third mode is designed, fabricated, and measured to validate the method. The measured broadside gain of the proposed compressed dipole reaches up to 4.6 dBi, 75% or 2.45 dBi higher than a conventional dipole.
Autors: Yu Luo;Zhi Ning Chen;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Nov 2017, volume: 65, issue:11, pages: 5697 - 5701
Publisher: IEEE
 
» Computation of Magnetic Liquid-Free Surface Shape in a Quasi-Homogeneous Magnetic Field With Differential Evolution
Abstract:
This paper presents a method to compute the magnetic liquid-free surface shape of a single spike in a quasi-homogeneous magnetic field produced by the Helmholtz coil. In the Rosensweig instability, the magnetic liquid-free surface deforms in a spike-like shape pattern as a magnetic field above some critical value is applied to the liquid. The free surface of the magnetic liquid is described as a polynomial function in cylindrical coordinates with the applied cylindrical symmetry. To obtain the shape deformation, the system of nonlinear magnetically augmented Young-Laplace equations is solved iteratively. The approach to the solution is executed in two steps. In the first step, magnetic field distribution along the surface is computed by the finite-element method. When magnetic field distribution is known, the second step occurs in which the system of Young-Laplace equations, defined as an optimization problem, is solved by differential evolution.
Autors: Mislav Trbušić;Anton Hamler;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Computational Creativity Exercises: An Avenue for Promoting Learning in Computer Science
Abstract:
Computational thinking and creative thinking are valuable tools both within and outside of computer science (CS). The goal of the project discussed here is to increase students’ achievement in CS courses through a series of computational creativity exercises (CCEs). In this paper, the framework of CCEs is described, and the results of two separate studies on their impact on student achievement are presented. Students in introductory CS courses completed CCEs as part of those courses. Students in Study 1 came from a variety of programs, and students in Study 2 were engineering majors. A profiling approach was used to test whether the impact of the CCEs could be accounted for by differences in students’ motivated and self-regulated engagement. Overall, CCEs had positive impacts on students’ grades and knowledge test scores, and although there were differences in achievement across the profiles, the impact of the CCEs was generally consistent across profiles. The CCEs appear to be a promising way to increase student achievement in introductory CS courses. Implications and directions for future research are discussed.
Autors: Markeya S. Peteranetz;Abraham E. Flanigan;Duane F. Shell;Leen-Kiat Soh;
Appeared in: IEEE Transactions on Education
Publication date: Nov 2017, volume: 60, issue:4, pages: 305 - 313
Publisher: IEEE
 
» Computational Intelligence in Aerospace Science and Engineering [Guest Editorial]
Abstract:
The articles in this special section focus on the use of computational intelligence in the aerospace industry. In an expanding world with limited resources, Computational Intelligence has become a necessity to handle the complexity of systems and processes. The aerospace sector, in particular, has stringent performance requirements on highly complex systems for which solutions are expected to be optimal and reliable at the same time. Computational intelligence techniques have been widely used to find solutions to global single or multi-objective optimization problems, including mixed variables, multi-modal and non-differentiable quantities.
Autors: Massimiliano Vasile;Edmondo Minisci;Ke Tang;
Appeared in: IEEE Computational Intelligence Magazine
Publication date: Nov 2017, volume: 12, issue:4, pages: 12 - 13
Publisher: IEEE
 
» Computationally Tractable Algorithms for Finding a Subset of Non-Defective Items From a Large Population
Abstract:
In the classical non-adaptive group testing setup, pools of items are tested together, and the main goal of a recovery algorithm is to identify the complete defective set given the outcomes of different group tests. In contrast, the main goal of a non-defective subset recovery algorithm is to identify a subset of non-defective items given the test outcomes. In this paper, we present a suite of computationally efficient and analytically tractable non-defective subset recovery algorithms. By analyzing the probability of error of the algorithms, we obtain bounds on the number of tests required for non-defective subset recovery with arbitrarily small probability of error. Our analysis accounts for the impact of both the additive noise (false positives) and dilution noise (false negatives). By comparing with information theoretic lower bounds, we show that the upper bounds on the number of tests are orderwise tight up to a factor, where is the number of defective items. We also provide simulation results that compare the relative performance of the different algorithms and reveal insights into their practical utility. The proposed algorithms significantly outperform the straightforward approaches of testing items one-by-one, and of first identifying the defective set and then choosing the non-defective items from the complement set, in terms of the number of measurements required to ensure a given success rate.
Autors: Abhay Sharma;Chandra R. Murthy;
Appeared in: IEEE Transactions on Information Theory
Publication date: Nov 2017, volume: 63, issue:11, pages: 7149 - 7165
Publisher: IEEE
 
» Computer Generation of High Throughput and Memory Efficient Sorting Designs on FPGA
Abstract:
Accelerating sorting using dedicated hardware to fully utilize the memory bandwidth for Big Data applications has gained much interest in the research community. Recently, parallel sorting networks have been widely employed in hardware implementations due to their high data parallelism and low control overhead. In this paper, we propose a systematic methodology for mapping large-scale bitonic sorting networks onto FPGA. To realize data permutations in the sorting network, we develop a novel RAM-based design by vertically “folding” the classic Clos network. By utilizing the proposed design for data permutation, we develop a hardware generator to automatically build bitonic sorting architectures on FPGAs. For given input size, data width and data parallelism, the hardware generator specializes both the datapath and the control unit for sorting and generates a design in high level hardware description language. We demonstrate trade-offs among throughput, latency and area using two illustrative sorting designs including a high throughput design and a resource efficient design. With a data parallelism of , the high throughput design sorts an -key sequence with latency , throughput results per cycle and uses memory. This achieves optimal memory efficiency (defined as the ratio of throughput to the amount of on-chip memory used by the design) and outperforms the state-of-the-art. Experimental results show that the designs obtained by our proposed hardware generator achieve 49 to 112 percent improvement in energy efficiency and 56 to 430 percent higher memory efficiency compared with the state-of-the-art.
Autors: Ren Chen;Viktor K. Prasanna;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Nov 2017, volume: 28, issue:11, pages: 3100 - 3113
Publisher: IEEE
 
» Computer Graphics Animation for Objective Self-Evaluation
Abstract:
The increased number of students enrolling in dance classes in Japan has resulted in a shortage of qualified instructors, leaving classes to be taught by instructors who are not trained in dance. The authors developed a system specifically designed to help nonqualified dance instructors teach dance using motion capture and animation. The goal is to allow dancers to easily self-evaluate their own performances by comparing it to a standard example.
Autors: Yoko Usui;Katsumi Sato;Shinichi Watabe;
Appeared in: IEEE Computer Graphics and Applications
Publication date: Nov 2017, volume: 37, issue:6, pages: 5 - 9
Publisher: IEEE
 
» Computing the Coupling Resistances in High-Current Instrument Transformers Considering Skin and Proximity Effect
Abstract:
This paper presents a simplified method to compute the frequency-dependent coupling resistances inside high-current instrument transformers (HCTs). The solution of the 1-D Helmholtz equation is used to estimate the losses inside the winding layers dependent on the frequency of the exciting current. The resistive couplings inside the HCT are determined by computing the total winding losses inside the HCT and differentiating the loss equation. An equivalent proximity depth for HCTs is defined by assessing the losses component of skin and proximity effect. This quantity, which only depends on the skin depth and the number of winding layers, enables to estimate the limit beyond which the proximity effect causes high losses inside the winding. A computation example shows the results of the model.
Autors: Christian Jäschke;Peter Schegner;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 7
Publisher: IEEE
 
» Computing the Feasible Spaces of Optimal Power Flow Problems
Abstract:
The solution to an optimal power flow (OPF) problem provides a minimum cost operating point for an electric power system. The performance of OPF solution techniques strongly depends on the problem's feasible space. This paper presents an algorithm that is guaranteed to compute the entire feasible spaces of small OPF problems to within a specified discretization tolerance. Specifically, the feasible space is computed by discretizing certain of the OPF problem's inequality constraints to obtain a set of power flow equations. All solutions to the power flow equations at each discretization point are obtained using the Numerical Polynomial Homotopy Continuation algorithm. To improve computational tractability, “bound tightening” and “grid pruning” algorithms use convex relaxations to preclude consideration of many discretization points that are infeasible for the OPF problem. The proposed algorithm is used to generate the feasible spaces of two small test cases.
Autors: Daniel K. Molzahn;
Appeared in: IEEE Transactions on Power Systems
Publication date: Nov 2017, volume: 32, issue:6, pages: 4752 - 4763
Publisher: IEEE
 
» Conference Calendar [Conference Calendar]
Abstract:
Presents the CIS upcoming calendar of events and meetings.
Autors: Bernadette Bouchon-Meunier;
Appeared in: IEEE Computational Intelligence Magazine
Publication date: Nov 2017, volume: 12, issue:4, pages: 102 - 102
Publisher: IEEE
 
» Conference Report on 2017 IEEE Congress on Evolutionary Computation (IEEE CEC 2017) [Conference Reports]
Abstract:
Presents information on the 2017 IEEE Congress on Evolutionary Computation.
Autors: Jose A. Lozano;
Appeared in: IEEE Computational Intelligence Magazine
Publication date: Nov 2017, volume: 12, issue:4, pages: 5 - 6
Publisher: IEEE
 
» Conference Report on 2017 IEEE International Conference on Fuzzy Systems (FUZZ-IEEE 2017) [Conference Reports]
Abstract:
Presents information on the 2017 IEEE International Conference on Fuzzy Systems.
Autors: Giovanni Acampora;Bruno Siciliano;Hani Hagras;Francisco Herrera;
Appeared in: IEEE Computational Intelligence Magazine
Publication date: Nov 2017, volume: 12, issue:4, pages: 6 - 8
Publisher: IEEE
 
» Congestion-aware local reroute for fast failure recovery in software-defined networks
Abstract:
Although a restoration approach derives a reroute path when failure occurs and greatly reduces forwarding rules in switches compared with a protection approach, software-defined networks (SDNs) induce a long failure recovery process because of frequent flow operations between the SDN controller and switches. Accordingly, it is indispensable to design a new resilience approach to balance failure recovery time and forwarding rule occupation. To this end, we leverage flexible flow aggregation in fast reroute to solve this problem. In the proposed approach, each disrupted traffic flow is reassigned to a local reroute path for the purpose of congestion avoidance. Thus, all traffic flows assigned to the same local reroute path are aggregated into a new “big” flow, and the number of reconfigured forwarding rules in the restoration process is greatly reduced. We first formulate this problem as an integer linear programming model, then design an efficient heuristic named the “congestion-aware local fast reroute” (CALFR). Extensive emulation results show that CALFR enables fast recovery while avoiding link congestion in the post-recovery network.
Autors: Zijing Cheng;Xiaoning Zhang;Yichao Li;Shui Yu;Rongping Lin;Lei He;
Appeared in: IEEE/OSA Journal of Optical Communications and Networking
Publication date: Nov 2017, volume: 9, issue:11, pages: 934 - 944
Publisher: IEEE
 
» Consolidation of (001)-Oriented Fe–Ga Flakes for 3-D Printing of Magnetostrictive Powder Materials
Abstract:
Additive manufacturing (AM) of metallic materials is an emerging technique for the printing of 3-D components using metal powders. The use of thin flakes of magnetostrictive (001)-oriented Fe–Ga powder in a composite matrix for the design of pressure and strain sensors has been demonstrated. This paper extends that work and presents a preliminary evaluation of two methods for the consolidation of magnetostrictive Fe–Ga alloy flakes, using a hot press and arc melting. Flake-shaped powders of Fe80Ga20 and Fe73Ga27 alloys were prepared with varying particle sizes up to in diameter using a high energy wet ball milling process. The surfaces of the flakes produced were predominantly parallel to the (001) crystallographic plane. Hot pressed Fe–Ga disk samples at 850 °C showed increases of packing density and saturation magnetization with an increase of the particle size because higher thickness to diameter aspect ratios in the flakes facilitated ordering of flakes whereby they more easily defaulted to sitting on one another in layers. We also employed arc melting and binder infiltration techniques to demonstrate the potential suitability of the oriented flake form of this magnetostrictive alloy for AM using 3-D printing methods.
Autors: Suok-Min Na;John Galuardi;Alison B. Flatau;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Constrained Band Subset Selection for Hyperspectral Imagery
Abstract:
This letter extends the constrained band selection (CBS) technique to constrained band subset selection (CBSS) in a similar manner that constrained energy minimization has been extended to linearly constrained minimum variance. CBSS constrains multiple bands as a band subset as opposed to CBS constraining a single band as a singleton set. To achieve this goal, CBSS requires a strategy to search for an optimal band subset, while CBS does not. In this letter, two new sequential algorithms, referred to as sequential CBSS and successive CBSS, which do not exist in CBS are derived for CBSS to find desired band subsets and to avoid exhaustive search.
Autors: Lin Wang;Hisao-Chi Li;Bai Xue;Chein-I Chang;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Nov 2017, volume: 14, issue:11, pages: 2032 - 2036
Publisher: IEEE
 
» Constrained Deep Weak Supervision for Histopathology Image Segmentation
Abstract:
In this paper, we develop a new weakly supervised learning algorithm to learn to segment cancerous regions in histopathology images. This paper is under a multiple instance learning (MIL) framework with a new formulation, deep weak supervision (DWS); we also propose an effective way to introduce constraints to our neural networks to assist the learning process. The contributions of our algorithm are threefold: 1) we build an end-to-end learning system that segments cancerous regions with fully convolutional networks (FCNs) in which image-to-image weakly-supervised learning is performed; 2) we develop a DWS formulation to exploit multi-scale learning under weak supervision within FCNs; and 3) constraints about positive instances are introduced in our approach to effectively explore additional weakly supervised information that is easy to obtain and enjoy a significant boost to the learning process. The proposed algorithm, abbreviated as DWS-MIL, is easy to implement and can be trained efficiently. Our system demonstrates the state-of-the-art results on large-scale histopathology image data sets and can be applied to various applications in medical imaging beyond histopathology images, such as MRI, CT, and ultrasound images.
Autors: Zhipeng Jia;Xingyi Huang;Eric I-Chao Chang;Yan Xu;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Nov 2017, volume: 36, issue:11, pages: 2376 - 2388
Publisher: IEEE
 
» Constraint Programming Approach for Scheduling Jobs With Release Times, Non-Identical Sizes, and Incompatible Families on Parallel Batching Machines
Abstract:
We study a parallel batch-scheduling problem that involves the constraints of different job release times, non-identical job sizes, and incompatible job families, is addressed. Mixed integer programming and constraint programming (CP) models are proposed and tested on a set of common problem instances from a paper in the literature. Then, we compare the performance of the models with that of a variable neighborhood search (VNS) heuristic from the same paper. Computational results show that CP outperforms VNS with respect to solution quality and run time by 3.4%–6.8% and 47%–91%, respectively. When compared to optimal solutions, the results demonstrate CP is capable of generating a near optimal solution in a short amount of time.
Autors: Andy Ham;John W. Fowler;Eray Cakici;
Appeared in: IEEE Transactions on Semiconductor Manufacturing
Publication date: Nov 2017, volume: 30, issue:4, pages: 500 - 507
Publisher: IEEE
 
» Constraint Qualification Based Detection Method for Nodal Price Multiplicity
Abstract:
This paper proposes a fast, standalone method for detecting multiple dual solutions (MDS) of the market dispatch problem. Using linear independence constraint qualification conditions and matrix theory, we characterize the conditions for MDS and develop a procedure for their detection. Our procedure exploits the structure of the market dispatch problem to improve computational efficiency. We demonstrate our method on eight nodal pricing scenarios, in four test systems.
Autors: Donghan Feng;Chang Liu;Zeyu Liu;Liang Zhang;Yangzhi Ding;Clay Campaigne;
Appeared in: IEEE Transactions on Power Systems
Publication date: Nov 2017, volume: 32, issue:6, pages: 4968 - 4969
Publisher: IEEE
 
» Construction of a Bit Stream Using Telegraphic Switching of a Two-Input Magnetic Tunnel Junction
Abstract:
Stochastic computing with probabilistic bit streams is a useful computing method due to its advantage of a higher degree of error tolerance than the conventional binary system. To achieve computational efficiency, electronic devices with an inherent stochastic nature have been explored for integration into a stochastic computing system. In this paper, we demonstrate probabilistic bit streams obtained from the telegraphic switching of a two-input magnetic tunnel junction (MTJ). Extension of the input configuration provides an advantage in architectural comparability for applying to a practical computing circuit. We also show that an MTJ can be a generic stochastic device, whose output directly constructs bit streams representing the probabilistic weight according to two independent progammable inputs, namely, the applied magnetic field and the current.
Autors: Gi Yoon Bae;Dong Ik Suh;Young-jae Kim;Hyungjune Lee;Wanjun Park;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Contactless Piston Position Transducer With Axial Excitation
Abstract:
Existing piston position transducers require either drilling precise hole into the piston bar, or mounting permanent magnets or measuring device inside the pressurized cylinder. We present a new solution for aluminum pneumatic cylinders, which uses the ferromagnetic bar inside the solenoid as a marker and linear array of fluxgate sensors as a scale. Instead of relying on dc remanence we use active ac excitation; the reading is resistant against external fields, both dc and ac. Using sensor array allows to compensate for temperature effects. The linear stroke of the individual sensor is 40 mm, so that array density should be about 30 mm. 1 mm position resolution is achievable. The weak point of the new transducer is the response time: for fast moving pistons the excitation frequency should be high, which leads to weaker signal and lower resolution.
Autors: Pavel Ripka;Andrey Chirtsov;Vaclav Grim;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Context-Aware Software Variability through Adaptable Interpreters
Abstract:
Dynamic adaptation to the execution context is desirable in software that operates in an evolving environment. Context-oriented programming (COP) languages address behavioral variability from the programming-language perspective. COP has proven to be a valid approach when software is developed from scratch. However, it might require invasive, error-prone modifications when contextual variability is introduced to existing software written in non-COP languages, especially when variability is implicit in language constructs. A proposed approach moves variability support from the language to the language implementation level. This enables contextual variability in any application independently of whether the underlying language supports COP. A Neverlang-based prototype implementation illustrates this approach.
Autors: Walter Cazzola;Albert Shaqiri;
Appeared in: IEEE Software
Publication date: Nov 2017, volume: 34, issue:6, pages: 83 - 88
Publisher: IEEE
 
» Continuous Asymptotically Tracking Control for a Class of Nonaffine-in-Input System With Nonvanishing Disturbance
Abstract:
In this paper, we explore the possibility of designing a continuous controller for a class of nonaffine system to achieve asymptotically tracking results with robustness to system uncertainties, unvanishing disturbances, and unknown control effectiveness. A robust integral of the sign of the error design is formulated to search a robust control for the nonaffine dynamics, while a time-varying gain of Nussbaum-type-function (NTF) is augmented to estimate the unknown direction and magnitude for control effectiveness. A second-order filter is employed to proceed the design when the NTF gain is involved without using any unmeasurable signals. Rigorous analysis shows that the proposed controller can asymptotically stabilizes the closed-loop system and the output tracking error. Simulation results on a Duffing–Holmes chaotic system demonstrate the effectiveness of the proposed approach.
Autors: Bin Xian;Yao Zhang;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Nov 2017, volume: 62, issue:11, pages: 6019 - 6025
Publisher: IEEE
 
» Continuous Sampled-Data Observer Design for Nonlinear Systems With Time Delay Larger or Smaller Than the Sampling Period
Abstract:
This technical note addresses the problem of high gain observer design for a class of triangular nonlinear systems with sampled and delayed output measurements. The transmission delay may be larger or smaller than the sampling period. Firstly, a class of hybrid systems are introduced, and sufficient conditions are proposed to guarantee that the hybrid systems are globally and exponentially stable. Then, a continuous-discrete observer is designed for the nonlinear systems. Based on these sufficient conditions and a specially constructed Lyapunov-Krasovskii functional, it is shown that the observation errors globally and exponentially converge to the origin. Finally, an illustrative example is used to verify the validity of the proposed design methods.
Autors: Daoyuan Zhang;Yanjun Shen;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Nov 2017, volume: 62, issue:11, pages: 5822 - 5829
Publisher: IEEE
 
» Contrast-Enhanced Magnetic Resonance Imaging of Gastric Emptying and Motility in Rats
Abstract:
The assessment of gastric emptying and motility in humans and animals typically requires radioactive imaging or invasive measurements. Here, we developed a robust strategy to image and characterize gastric emptying and motility in rats based on contrast-enhanced magnetic resonance imaging (MRI) and computer-assisted image processing. The animals were trained to naturally consume a gadolinium-labeled dietgel while bypassing any need for oral gavage. Following this test meal, the animals were scanned under low-dose anesthesia for high-resolution T1-weighted MRI in 7 Tesla, visualizing the time-varying distribution of the meal with greatly enhanced contrast against non-gastrointestinal (GI) tissues. Such contrast-enhanced images not only depicted the gastric anatomy, but also captured and quantified stomach emptying, intestinal filling, antral contraction, and intestinal absorption with fully automated image processing. Over four postingestion hours, the stomach emptied by 27%, largely attributed to the emptying of the forestomach rather than the corpus and the antrum, and most notable during the first 30 min. Stomach emptying was accompanied by intestinal filling for the first 2 h, whereas afterward intestinal absorption was observable as cumulative contrast enhancement in the renal medulla. The antral contraction was captured as a peristaltic wave propagating from the proximal to distal antrum. The frequency, velocity, and amplitude of the antral contraction were on average 6.34 ± 0.07 contractions per minute, 0.67 ± 0.01 mm/s, and 30.58 ± 1.03%, respectively. These results demonstrate an optimized MRI-based strategy to assess gastric emptying and motility in healthy rats, paving the way for using this technique to understand GI diseases, or test new therapeutics in rat models.
Autors: Kun-Han Lu;Jiayue Cao;Steven Thomas Oleson;Terry L. Powley;Zhongming Liu;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Nov 2017, volume: 64, issue:11, pages: 2546 - 2554
Publisher: IEEE
 
» Control and Release in Complex Relationships
Abstract:
Artist James Alan Smith is driven to involve himself in the creative process, whether through coding or visual art. The effect of his abstract and representation pieces is extraordinary and mysterious, and each encourages viewers to see the complex relationships between the various layers.
Autors: Gary Singh;
Appeared in: IEEE Computer Graphics and Applications
Publication date: Nov 2017, volume: 37, issue:6, pages: 3 - 4
Publisher: IEEE
 

Publication archives by date

  2017:   January     February     March     April     May     June     July     August     September     October     November     December    

  2016:   January     February     March     April     May     June     July     August     September     October     November     December    

  2015:   January     February     March     April     May     June     July     August     September     October     November     December    

  2014:   January     February     March     April     May     June     July     August     September     October     November     December    

  2013:   January     February     March     April     May     June     July     August     September     October     November     December    

  2012:   January     February     March     April     May     June     July     August     September     October     November     December    

  2011:   January     February     March     April     May     June     July     August     September     October     November     December    

  2010:   January     February     March     April     May     June     July     August     September     October     November     December    

  2009:   January     February     March     April     May     June     July     August     September     October     November     December    

 
0-C     D-L     M-R     S-Z