Electrical and Electronics Engineering publications abstract of: 11-2017 sorted by title, page: 14

» On-Orbit Characterization of the MODIS SDSM Screen for Solar Diffuser Degradation Estimation
Abstract:
Moderate Resolution Imaging Spectroradiometer (MODIS) reflective solar bands (RSBs) are calibrated on-orbit using a solar diffuser (SD) with its degradation tracked by an onboard SD stability monitor (SDSM). The SDSM has nine detectors with wavelengths from 0.41 to 0.94 . It is operated during each scheduled SD calibration event, making alternate observations of the sun and the SD. Due to erroneous design parameters, which led to the misalignment of the key elements in the SDSM, there are significant ripples in the sun view responses as the solar viewing angle changes. At the mission beginning, the effect of the ripples was eliminated by normalizing each SDSM detector response to the response of detector 9 (D9) at 0.94 , assuming that D9 had no degradation. However, D9 degradation increases over MODIS operation times. Degradation of up to 2% has recently been observed in D9 for the Terra MODIS. A newly implemented approach reduces the sun view ripples using a lookup table constructed using SDSM data carefully selected from a short period early in the mission lifetime. In this paper, we provide an overview of different approaches that have been applied over the years by the MODIS Characterization Support Team to track the on-orbit SD degradation. We evaluate the overall SD and SDSM on-orbit performance for both Terra and Aqua MODIS, as well as the impact on the MODIS RSB calibration uncertainty.
Autors: Hongda Chen;Xiaoxiong Xiong;Amit Angal;Kevin A. Twedt;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Nov 2017, volume: 55, issue:11, pages: 6456 - 6467
Publisher: IEEE
 
» On-Orbit Line Spread Function Estimation of the SNPP VIIRS Imaging System From Lake Pontchartrain Causeway Bridge Images
Abstract:
The visible infrared imaging radiometer suite (VIIRS) instrument was launched on October 28, 2011 onboard the Suomi National Polar-Orbiting Partnership (SNPP) satellite. The VIIRS instrument is a whiskbroom system with 22 spectral and thermal bands split between 16 moderate resolution bands (M-bands), five imagery resolution bands (I-bands), and a day–night band. In this study, we estimate the along-scan line spread function (LSF) of the I-bands and M-bands based on measurements performed on images of the Lake Pontchartrain Causeway Bridge. In doing so, we develop a model for the LSF that closely matches the prelaunch laboratory measurements. We utilize VIIRS images co-geolocated with a Landsat TM image to precisely locate the bridge linear feature in the VIIRS images as a linear best fit to a straight line. We then utilize nonlinear optimization to compute the best fit equation of the VIIRS image measurements in the vicinity of the bridge to the developed model equation. From the found parameterization of the model equation, we derive the full-width at half-maximum as an approximation of the sensor field of view for all bands, and compare these on-orbit measured values with prelaunch laboratory results.
Autors: James C. Tilton;Robert E. Wolfe;Guoqing Lin;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Nov 2017, volume: 10, issue:11, pages: 5056 - 5072
Publisher: IEEE
 
» Open-Contour Tracking Using a New State-Space Model and Nonrigid Motion Training
Abstract:
Object tracking in a video sequence is usually achieved by tracking the bounding box over the object or the object’s boundary, each of which has somewhat different applications. In this paper, we present a new open-contour tracking algorithm based on a Bayesian framework in which the contour is a part of the object’s boundary. We first propose a new state-space model for the representation of contours, which can handle the rigid and nonrigid motions of contours independently. This model enables us to focus on the nonrigid motions during the training, and the model works for challenging rigid motion scenarios. In addition, for the robust tracking of contours, we propose a measurement function that considers the contrast on object boundaries, target appearance, and temporal coherence. We applied the proposed method to two kinds of open-contours targets, and the experimental results show that the proposed method achieves superior performance to the conventional contour tracking methods. The proposed method is also compared with recent bounding box tracking methods for the object tracking purposes, and the comparison shows that the proposed method works robustly to fast motions and yields a more accurate estimate of an object’s location than the conventional bounding box tracking methods.
Autors: Seon Heo;Hyung Il Koo;Nam Ik Cho;
Appeared in: IEEE Transactions on Circuits and Systems for Video Technology
Publication date: Nov 2017, volume: 27, issue:11, pages: 2355 - 2366
Publisher: IEEE
 
» Operating Waterside: Interesting Facts About How It Was Done [History]
Abstract:
Waterside was an iconic generating station built by the New York Edison Company and later operated by the Consolidated Edison Company of New York. It served as a primary source of electric power for Manhattan island throughout the 20th century. The following is not an exhaustive technical history of the station but, rather, a collection of interesting facts regarding procedures involved in operating this huge facility over the decades of its existence.
Autors: Thomas J. Blalock;
Appeared in: IEEE Power and Energy Magazine
Publication date: Nov 2017, volume: 15, issue:6, pages: 94 - 108
Publisher: IEEE
 
» Operation Strategy of Multi-Energy Storage System for Ancillary Services
Abstract:
Energy storage systems (ESSs) used for ancillary purposes in power systems have different capacities and output characteristics, and so need to be scheduled and operated together based on their state of charge rather than individually. This paper proposes a simple but effective method to allocate the energy required for spinning reserve or frequency regulation, properly to each ESS within a multi-ESS with the aim of improving system reliability. For this, an ESS reliability model is first proposed, and the reliability of the entire system is then evaluated using reliability models for other utilities such as conventional generators and renewable energy sources. To better demonstrate the improvement in reliability, two new reliability indices are introduced besides the existing indices: loss of frequency probability and loss of duration probability. Through case studies, it is shown that the required power is more effectively distributed across each ESS by the allocation method and thus the method can contribute to securing more spinning reserve and alleviating more frequency fluctuation, rather than the conventional method.
Autors: Wook-Won Kim;Je-Seok Shin;Jin-O Kim;
Appeared in: IEEE Transactions on Power Systems
Publication date: Nov 2017, volume: 32, issue:6, pages: 4409 - 4417
Publisher: IEEE
 
» Operator Safety and Field Focality in Aluminum Shielded Transcranial Magnetic Stimulation
Abstract:
This paper aims at verifying the effectiveness of the transcranial magnetic stimulation treatment when a passive shield is introduced for the nursing staff safety. The analysis is developed through a modeling approach, splitting the solution of the field problem into two successive steps. The Duke anatomical model of the Virtual Family dataset is used to model both the patient head and the operator body. The investigations are performed by considering stimulators equipped with a circular spiral coil or a figure-of-eight shaped (FoE or butterfly) winding. The addition of the shield slightly reduces the induced electric field values, while increasing the field focality in the patient brain (especially with the circular coil), preserving the effectiveness of the treatment, anyway. On the operators’ side, the presence of a passive conductive shield significantly reduces the exposure levels.
Autors: Mauro Zucca;Oriano Bottauscio;Mario Chiampi;Luca Zilberti;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Optical Emission Spectrum Processing Using Wavelet Compression During Wafer Fabrication
Abstract:
This paper describes the application of discrete-wavelet transform (DWT)-based algorithms to compress optical emission spectral intensity data collected during wafer fabrication. The major goal is to seek computationally efficient compression algorithms that can significantly reduce the data storage requirement but also are capable of retaining enough data authenticity critical for diagnostic purposes. The potential benefits will provide a promising foundation for an integrated data collection and compression tool. The optical emission data are treated in this paper either as images for the whole spectrum or bands of time series and are treated accordingly using appropriate DWT compression approaches. We have found through representative simulation examples that using the set partitioning in hierarchical trees compression algorithm it is achievable to obtain better than 99% storage reduction for optical emission spectrum (OES) images. For OES time series we have achieved around 95% storage reduction with Daubechies and Haar wavelets. The storage reductions are achieved while maintaining sufficient authenticity to retain the dynamic nature of OES data for diagnostic purposes.
Autors: Taikang Ning;Chung Ho Huang;John Albert Jensen;Vincent Wong;Henry Chan;
Appeared in: IEEE Transactions on Semiconductor Manufacturing
Publication date: Nov 2017, volume: 30, issue:4, pages: 380 - 387
Publisher: IEEE
 
» Optically 3-D $mu $ -Printed Ferrule-Top Polymer Suspended-Mirror Devices
Abstract:
We present a novel optical microfabrication technology to directly print polymer suspended-mirror devices (SMDs) on the end face of fiber-optic ferrules. With an own-established optical 3-D -printing platform, three kinds of ferrule-top SMDs were rapidly fabricated by using SU-8 photoresist. Optical reflection spectra of the fabricated SMDs were measured and then analyzed by using fast Fourier transform. The application of the ferrule-top SMD as a miniature displacement sensor was experimentally demonstrated.
Autors: Mian Yao;Jushuai Wu;A. Ping Zhang;Hwa-Yaw Tam;P. K. A. Wai;
Appeared in: IEEE Sensors Journal
Publication date: Nov 2017, volume: 17, issue:22, pages: 7257 - 7261
Publisher: IEEE
 
» Optically-Enabled Bloom Filter Label Forwarding Using a Silicon Photonic Switching Matrix
Abstract:
Simplified forwarding schemes relying on Bloom filter (BF)-based labels emerge as a promising approach for coping with the substantial increase in lookup table memory requirements associated with the growing number of end-hosts in DataCenters. In this paper, we present for the first time the successful implementation of a BF-label forwarding scheme over a silicon photonic switch fabric and we demonstrate its functionality with 10 Gb/s data packets that carry BF-encoded labels. The optically enabled BF-label forwarding setup utilizes a Si-based 4 × 4 electro-optic switch directly controlled by an amplifier-less and digital-to-analog-converter-less high speed Field Programmable Gate Array board. The FPGA is responsible for extracting the BF-label from the incoming packets and for carrying out the BF-based forwarding function, determining the appropriate switching state towards conveying incoming packets to the desired output. The use of BF-label forwarding allows for rapid switch reconfiguration avoiding the need for large look-up table updates as the network topology changes and devices are added, removed or simply change physical location. Successful operation for 10 Gb/s data packets has been obtained for a 1 × 4 routing layout.
Autors: N. Terzenidis;M. Moralis-Pegios;C. Vagionas;S. Pitris;E. Chatzianagnostou;P. Maniotis;D. Syrivelis;L. Tassiulas;A. Miliou;N. Pleros;K. Vyrsokinos;
Appeared in: Journal of Lightwave Technology
Publication date: Nov 2017, volume: 35, issue:21, pages: 4758 - 4765
Publisher: IEEE
 
» Optimal Allocation of Dynamic Var Sources Using the Voronoi Diagram Method Integrating Linear Programing
Abstract:
Dynamic reactive power (var) sources can effectively mitigate fault-induced delayed voltage recovery (FIDVR) issues. This paper optimizes the sizes of dynamic var sources at given locations against FIDVR issues under severe contingencies. First, the geometric characteristics about the non-convex solution space of this problem are studied. Accordingly, a Voronoi diagram approach integrating linear programming (LP) is proposed, which disperses a number of sample points of potential solutions in the searching space to construct a Voronoi diagram blending the local cost functions over the entire space by Barycentric interpolation in Voronoi regions. New sample points are then recursively added, including the tentative optimal point using LP, the most depopulated area point ensuring global fidelity, and the connecting point, until the stopping criterion is met. The new approach is demonstrated in detail on the WSCC 9-bus system. A case study on the NPCC 140-bus system also validates that the proposed approach can effectively estimate the boundary and the geometry of the feasible solution region in the searching space and find the optimal solution.
Autors: Weihong Huang;Kai Sun;Junjian Qi;Jiaxin Ning;
Appeared in: IEEE Transactions on Power Systems
Publication date: Nov 2017, volume: 32, issue:6, pages: 4644 - 4655
Publisher: IEEE
 
» Optimal Angle Combination for Improving Electromagnetic Torque in Induction Motor With Double-Skewed Rotor
Abstract:
Double-skewed rotor is of great benefit to decrease harmonic magnetic fields in induction motors. But the fundamental magnetic field is damaged as well as the electromagnetic torque, like the case of normal skewed rotor. The effect of skew angle and stagger angle on the fundamental torque is studied in this paper. With the multi-slice theory, the double-skewing factor is proposed to determine the range of angle combination. Then, the range is shortened by the deduced torque coefficient with virtual displacement method. Compared with the general recommendation, the final angle combination is optimal and widely suitable for the double-skewed rotor. A higher pullout electromagnetic torque will be attained under this condition. With the finite elements-method, the validity of analysis model can be verified by the comparison of two kinds of motors.
Autors: Wei Xu;Xiaohua Bao;Chong Di;Lang Wang;Yuanyang Chen;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Optimal Bit Allocation for CTU Level Rate Control in HEVC
Abstract:
For High Efficiency Video Coding (HEVC), the R– scheme is the latest rate control (RC) scheme, which investigates the relationships among allocated bits, the slope of rate-distortion (R-D) curve , and quantization parameter. However, we argue that bit allocation in the existing R– scheme is not optimal. In this paper, we therefore propose an optimal bit allocation (OBA) scheme for coding tree unit level RC in HEVC. Specifically, to achieve the OBA, we first develop an optimization formulation with a novel R-D estimation, instead of the existing R– estimation. Unfortunately, it is intractable to obtain a closed-form solution to the optimization formulation. We thus propose a recursive Taylor expansion (RTE) method to iteratively solve the formulation. As a result, an approximate closed-form solution can be obtained, thus achieving OBA and bit reallocation. Both theoretical and numerical analyses show the fast convergence speed and little computational time of the proposed RTE method. Therefore, our OBA scheme can be achieved at little encoding complexity cost. Finally, the experimental results validate the effectiveness of our scheme in three aspects: R-D performance, RC accuracy, and robustness over dynamic scene changes.
Autors: Shengxi Li;Mai Xu;Zulin Wang;Xiaoyan Sun;
Appeared in: IEEE Transactions on Circuits and Systems for Video Technology
Publication date: Nov 2017, volume: 27, issue:11, pages: 2409 - 2424
Publisher: IEEE
 
» Optimal Design of an Inset PM Motor With Assisted Barriers and Magnet Shifting for Improvement of Torque Characteristics
Abstract:
This paper presents an optimal design of an inset permanent magnet (PM) motor for improved torque characteristics. The key of the design is to introduce a bidirectional way of magnet shifting, along with assisted air barriers, into an inset PM motor, where magnets are shifted clockwise or anti-clockwise as needed. The introduced bidirectional shifting way lowers the requirement for shifting space between poles and also can reduce undesirable radial force to decrease vibration and noise. Moreover, the proposed inset PM motor can guarantee the torque density with great reduction of on-load torque ripple because the assisted air barriers can not only enhance the utilization of reluctance torque but also will not introduce any other torque harmonic and even can reduce torque ripple further. Also, the analytical expressions of torques are established and the appropriate angles of magnets shifting and assisted air barriers are, respectively, chosen to obtain low torque ripple and optimal torque density. Finally, these theoretical analyses are verified by the finite-element method.
Autors: Xinxin Du;Guohai Liu;Qian Chen;Gaohong Xu;Meimei Xu;Xun Fan;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Optimal Design of Electromagnetic Energy Harvester Using Analytic Equations
Abstract:
When electromagnetic (EM) energy harvesters are designed, it is common to use finite-element analysis to investigate or verify the input–output relationships. However, it requires significant computational resources if the system is nonlinear or if it is necessary to find the time-domain behavior of the harvester. If analytic or semi-analytic equations describing the field distribution are available, it would be useful for design optimization where numerous design variations must be evaluated and compared. In this paper, the field distribution around an array of permanent magnets is obtained using the method of equivalent current sheets and the method of image sources. Then, the interaction between the magnetic force and the induced voltage is modeled as nonlinear electrical damping in contrast to a damping constant which the existing literature commonly employs. The nonlinear system model is validated against the test results obtained from a prototype EM harvester. Finally, a design optimization is performed using the proposed model, resulting in an increase in the output power by 18% from the initial design.
Autors: Hyeonseok Lee;Myounggyu D. Noh;Young-Woo Park;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Optimal Design of Wound Field Synchronous Reluctance Machines to Improve Torque by Increasing the Saliency Ratio
Abstract:
This paper proposes an optimal design for a salient pole wound field synchronous machine (WFSM) with a single flux barrier to improve torque performance and obtain a wide operating range, simultaneously. The proposed WFSM motor can effectively decrease -axis inductance to improve the saliency ratio ( and increase the reluctance torque. To maximize the saliency ratio and improve the torque characteristics, the single flux barrier is optimized, considering the magnetic saturation that uses Kriging method based on Latin hypercube sampling and a genetic algorithm. The 2-D finite element analysis results by the aid of JMAG-Designer shows that the saliency ratio , the reluctance torque, and the total torque of the optimal model are increased by 9.27%, 20.45%, and 6.17%, respectively, compared with those of the basic model. Finally, the performance of the optimal motor is verified through an experimental test, which indicates good agreement with the simulation results.
Autors: Wenping Chai;Wenliang Zhao;Byung-il Kwon;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Optimal Differentiator Filter Banks for PMUs and Their Feasibility Limits
Abstract:
In this paper, we present a very general design approach for optimal linear-phase differentiator filter banks for phasor measurement units based on convex semi-infinite optimization. A detailed presentation of the formulation of both the cost functions and constraints is included for the positive-sequence phasor estimation problem. The design method is extremely powerful and flexible as it allows to control precisely the behavior of the system in terms of the total vector error (TVE), frequency error (FE), and rate of change of frequency error (RFE) metrics for several different scenarios. This feature is extremely useful for tailored designs of these filters for different applications. We also determine numerically the uniform feasibility limits of the system as a function of the filter lengths and, in particular, study the required filter lengths for compliance with the IEEE Standards C37.118.1-2011 and C37.118.1a-2014. It is found that all requirements can be achieved with a significant margin with the exception of the M class FE constraint for interharmonic components, an issue which is also reported in other works and briefly discussed here. Finally, an interesting comparison with the Taylor-Fourier filters is made to illustrate the advantages of our approach.
Autors: Francisco Messina;Leonardo Rey Vega;Pablo Marchi;Cecilia G. Galarza;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Nov 2017, volume: 66, issue:11, pages: 2948 - 2956
Publisher: IEEE
 
» Optimal DoF Region of the $K$ -User MISO BC With Partial CSIT
Abstract:
We consider the -user multiple-input-single-output broadcast channel, where the transmitter, equipped with antennas, serves users, with . The transmitter has access to a partial channel state information of the users. This is modeled by letting the variance of the channel state information at the transmitter error of user scale as ) for the signal-to-noise ratio and some constant . In this letter, we derive the optimal degrees-of-freedom region in such setting, and we show that rate-splitting is the key scheme to achieve such a region.
Autors: Enrico Piovano;Bruno Clerckx;
Appeared in: IEEE Communications Letters
Publication date: Nov 2017, volume: 21, issue:11, pages: 2368 - 2371
Publisher: IEEE
 
» Optimal Estimation With Missing Observations via Balanced Time-Symmetric Stochastic Models
Abstract:
We consider data fusion for the purpose of smoothing and interpolation based on observation records with missing data. Stochastic processes are generated by linear stochastic models. The paper begins by drawing a connection between time reversal in stochastic systems and all-pass extensions. A particular normalization (choice of basis) between the two time-directions allows the two to share the same orthonormalized state process and simplifies the mathematics of data fusion. In this framework, we derive symmetric and balanced Mayne–Fraser-like formulas that apply simultaneously to continuous-time smoothing and interpolation, providing a definitive unification of these concepts. The absence of data over subintervals requires in general a hybrid filtering approach involving both continuous-time and discrete-time filtering steps.
Autors: Tryphon T. Georgiou;Anders Lindquist;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Nov 2017, volume: 62, issue:11, pages: 5590 - 5603
Publisher: IEEE
 
» Optimal Finite-Length and Asymptotic Index Codes for Five or Fewer Receivers
Abstract:
Index coding models broadcast networks in which a sender sends different messages to different receivers simultaneously, where each receiver may know some of the messages a priori. The aim is to find the minimum (normalized) index codelength that the sender sends. This paper considers unicast index coding, where each receiver requests exactly one message, and each message is requested by exactly one receiver. Each unicast index-coding instances can be fully described by a directed graph and vice versa, where each vertex corresponds to one receiver. For any directed graph representing a unicast index-coding instance, we show that if a maximum acyclic induced subgraph (MAIS) is obtained by removing two or fewer vertices from the graph, then the minimum index codelength equals the number of vertices in the MAIS, and linear codes are optimal for the corresponding index-coding instance. Using this result, we solved all unicast index-coding instances with up to five receivers, which correspond to all graphs with up to five vertices. For 9818 non-isomorphic graphs among all graphs up to five vertices, we obtained the minimum index codelength for all message alphabet sizes; for the remaining 28 graphs, we obtained the minimum index codelength if the message alphabet size is for any positive integer . This work complements the result by Arbabjolfaei et al. (ISIT 2013), who solved all unicast index-coding instances with up to five receivers in the asymptotic regime, where the message alphabet size tends to infinity.
Autors: Lawrence Ong;
Appeared in: IEEE Transactions on Information Theory
Publication date: Nov 2017, volume: 63, issue:11, pages: 7116 - 7130
Publisher: IEEE
 
» Optimal Illumination and Color Consistency for Optical Remote-Sensing Image Mosaicking
Abstract:
Illumination and color consistency are very important for optical remote-sensing image mosaicking. In this letter, we propose a simple but effective technique that simultaneously performs image illumination and color correction for multiview images. In this framework, we first present an uneven illumination removal algorithm based on bright channel prior, which guarantees the illumination consistency inside a single image. We then adapt a pairwise color-correction method to coarsely align the color tone between source and reference images. In this stage, we give a new single-image quality metric which combines brightness deviation, color cast, and entropy together for automatic reference-image selection. Finally, we perform a least-squares adjustment (LSA) procedure to obtain optimal illumination and color consistency among multiview images. In detail, we first perform a pairwise image matching by using SIFT algorithm; once sparse local patch correspondences obtained, the illumination and color relationship between images can be established based on a global gamma correction model; the illumination and color errors can then be minimized by LSA. Extensive experiments on both challenging synthetic and real optical remote-sensing image data sets show that it significantly outperforms the compared state-of-the-art approaches. All the source code and data sets used in this letter are made public.1

https://sites.google.com/site/jiayuanli2016whu/home

Autors: Jiayuan Li;Qingwu Hu;Mingyao Ai;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Nov 2017, volume: 14, issue:11, pages: 1943 - 1947
Publisher: IEEE
 
» Optimal Offering and Operating Strategy for a Large Wind-Storage System as a Price Maker
Abstract:
Wind farms and energy storage systems are playing increasingly more important roles in power systems, which makes their offering nonnegligible in some markets. From the perspective of wind farm-energy storage systems (WF-ESS), this paper proposes an integrated strategy of day-ahead offering and real-time operation policies to maximize their overall profit. As participants with large capacity in electricity markets can influence cleared prices by strategic offering, a large scaled WF-ESS is assumed to be a price maker in day-ahead markets. Correspondingly, the strategy considers influence of offering quantity on cleared day-ahead prices, and adopts linear decision rules as the real-time control strategy. These allow enhancing overall profits from both day-ahead and balancing markets. The integrated price-maker strategy is formulated as a stochastic programming problem, where uncertainty of wind power generation and balancing prices are taken into account in the form of scenario sets, permitting to reformulate the optimization problem as a linear program. Case studies validate the effectiveness of the proposed strategy by highlighting and quantifying benefits comparing with the price-taker strategy, and also show the profit enhancement brought to the distributed resources.
Autors: Huajie Ding;Pierre Pinson;Zechun Hu;Jianhui Wang;Yonghua Song;
Appeared in: IEEE Transactions on Power Systems
Publication date: Nov 2017, volume: 32, issue:6, pages: 4904 - 4913
Publisher: IEEE
 
» Optimal Positioning Coordination for Multiple Linear Switched Reluctance Machines
Abstract:
This paper proposes a coordinated positioning control network for three direct drive, linear switched reluctance machines. To obtain the optimized network control parameters, the distributed linear quadratic regulator is applied. Different communication topologies are studied for both the dynamic tracking and the coordination performance of the network. Experimental results demonstrate that an absolute static tracking precision of can be achieved from the “cycle” communication topology and an absolute static coordination precision of can be obtained from the “path” communication topology.
Autors: J. F. Pan;Li Qiu;J. Zhu;Eric Cheng;Bo Zhang;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 6
Publisher: IEEE
 
» Optimal Pulse Processing, Pile-Up Decomposition, and Applications of Silicon Drift Detectors at LCLS
Abstract:
Silicon drift detectors (SDDs) revolutionized spectroscopy in fields as diverse as geology and dentistry. For a subset of experiments at ultra-fast, x-ray free-electron lasers (FELs), SDDs can make substantial contributions. Often the unknown spectrum is interesting, carrying science data, or the background measurement is useful to identify unexpected signals. Many measurements involve only several discrete photon energies known a priori, allowing single event decomposition of pile-up and spectroscopic photon counting. We designed a pulse function and demonstrated that the signal amplitude (i.e., proportional to the detected energy and obtained from fitting with the pulse function), rise time, and pulse height are interrelated and at short peaking times the pulse height and pulse area are not optimal estimators for detected energy; instead, the signal amplitude and rise time are obtained for each pulse by fitting, thus removing the need for pulse shaping. By avoiding pulse shaping, rise times of tens of nanoseconds resulted in reduced pulse pile-up and allowed decomposition of remaining pulse pile-up at photon separation times down to hundreds of nanoseconds while yielding time-of-arrival information with precision of 10 nanoseconds. Waveform fitting yields simultaneously high energy resolution and high counting rates (2 orders of magnitude higher than current digital pulse processors). At pulsed sources or high photon rates, photon pile-up still occurs. We showed that pile-up spectrum fitting is relatively simple and preferable to pile-up spectrum deconvolution.We developed a photon pile-up statistical model for constant intensity sources, extended it to variable intensity sources (typical for FELs) and used it to fit a complex pile-up spectrum. We subsequently developed a Bayesian pile-up decomposition method that allows decomposing pile-up of single events with up to 6 photons from 6 monochromatic lines with 99% accuracy. The usefulness of SDDs will - ontinue into the x-ray FEL era of science. Their successors, the ePixS hybrid pixel detectors, already offer hundreds of pixels, each with similar performance to an SDD, in a compact, robust and affordable package.
Autors: G. Blaj;C. J. Kenney;A. Dragone;G. Carini;S. Herrmann;P. Hart;A. Tomada;J. Koglin;G. Haller;S. Boutet;M. Messerschmidt;G. Williams;M. Chollet;G. Dakovski;S. Nelson;J. Pines;S. Song;J. Thayer;
Appeared in: IEEE Transactions on Nuclear Science
Publication date: Nov 2017, volume: 64, issue:11, pages: 2854 - 2868
Publisher: IEEE
 
» Optimal Rotor Design of an 150 kW-Class IPMSM by the 3-D Voltage–Inductance-Map Analysis Method
Abstract:
A method is presented to determine the detailed design of a 150 kW-class interior permanent-magnet synchronous motor. The basic designs of stator and rotor were determined, after dividing the designed models into the best and worst cases on the basis of the rotor-shaped parameters. First, the three-bridge basic model satisfying the structural (mechanical) safety factor of the rotor is proposed. The three-bridge basic model does not meet the required torque at rated and maximum speed compared to the no-bridge model. Therefore, it is necessary to perform the design analysis through the selection of various design parameters. However, it is hard and takes alot of time to perform an analysis with numerous shape parameters. Therefore, design parameters with the greatest effect on torque and induced voltage are found using the sensitivity analysis. And the 3-D voltage–inductance map parameters were analyzed. Then, the design of the final model was predicted. On the basis of this prediction, the final model was extracted with a trend analysis. Finally, the final model was validated with experiments.
Autors: Jun-Young Kim;Dong-Woo Kang;Tae-Chul Jeong;Dong-Hoon Jeong;Ju Lee;Sung-Gu Lee;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Optimal Scheduling for Interference Mitigation by Range Information
Abstract:
The multiple access scheduling decides how the channel is shared among the nodes in the network. Typically scheduling algorithms aims at increasing the channel utilization and thereby throughput of the network. This paper describes several algorithms for generating an optimal schedule in terms of channel utilization for multiple access by utilizing range information in a fully connected network. We also provide detailed analysis for the proposed algorithms performance in terms of their complexity, convergence, and effect of non-idealities in the network. The performance of the proposed schemes are compared with non-aided methods to quantify the benefits of using the range information in the communication. The proposed methods have several favorable properties for the scalable systems. We show that the proposed techniques yields better channel utilization and throughput as the number of nodes in the network increases. We provide simulation results in support of this claim. The proposed methods indicate that the throughput can be increased on average by times for typical network configurations.
Autors: Vijaya Yajnanarayana;Klas E. G. Magnusson;Rasmus Brandt;Satyam Dwivedi;Peter Händel;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: Nov 2017, volume: 16, issue:11, pages: 3167 - 3181
Publisher: IEEE
 
» Optimal Structure Design of Permanent Magnet Motors Based on a General Pattern of Rotor Topologies
Abstract:
For the purpose of saving energy resources, it is extremely expected to develop highly efficient electric motors. Different types of permanent magnet (PM) arrangement can significantly affect the performance of the motors. Conventionally, the arrangement of the PMs is determined by designer’s experience. This paper focuses on the optimal design of PM arrangement in PM synchronous motors (PMSMs). We present a general pattern of the PM arrangement in PMSM. By varying the parameters of the general pattern, it can produce different types of PM arrangement in the rotor. The employed approach combines the global optimization method with the finite-element method for solving the optimization of the PM structures. Based on the proposed general pattern and optimization methods, the best PM arrangement in the motor can be automatically determined. In order to reduce computing loading, this paper employs the response surface models for reducing the computing time of objective functions. In the end, numerical tests are designed to showcase the effectiveness of the proposed method.
Autors: Xiaoyu Liu;W. N. Fu;Shuangxia Niu;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Optimal Transmit Beamforming for Secure SWIPT in a Two-Tier HetNet
Abstract:
This letter investigates the artificial noise aided beamforming design for secure simultaneous wireless information and power transfer in a two-tier downlink heterogeneous network (HetNet), where one femtocell underlays one macrocell in co-channel deployment. Each energy receiver in femtocell can be considered as a potential eavesdropper for messages intended for information receiver (IR). Our objective is to maximize the secrecy rate at IR subject to the signal-to-interference-plus noise ratio requirements of macro users, transmit power constraint and energy harvesting constraint. Due to the non-convexity of the formulated problem, it cannot be solved directly. Thus, we propose a novel reformulation by using first-order Taylor expansion and successive convex approximation (SCA) techniques. Furthermore, an SCA-based algorithm with low complexity is proposed to arrive at provably convergent solution. Finally, numerical results evaluate the performance of the proposed algorithm.
Autors: Bin Li;Zesong Fei;Zheng Chu;
Appeared in: IEEE Communications Letters
Publication date: Nov 2017, volume: 21, issue:11, pages: 2476 - 2479
Publisher: IEEE
 
» Optimally Controlled Pure ALOHA Systems for Wireless Sensor Networks
Abstract:
Pure ALOHA would be one of the candidate techniques to realize low-power wide-area networks and various applications of Internet of Things with a huge number of low-cost end-devices (EDs) and sensors. No strict time-synchronization of pure ALOHA systems may reduce the hardware cost of sensors and system significantly. As such, this letter characterizes the performance of pure ALOHA systems in terms of throughput, access delay, and stability, and further proposes a particle-filter-based control algorithm for retransmission intervals of EDs to achieve near-optimal throughput performance.
Autors: Jun-Bae Seo;Hu Jin;
Appeared in: IEEE Communications Letters
Publication date: Nov 2017, volume: 21, issue:11, pages: 2460 - 2463
Publisher: IEEE
 
» Optimization Design of PMSM With Hybrid-Type Permanent Magnet Considering Irreversible Demagnetization
Abstract:
This paper proposes optimization design of permanent-magnet synchronous motor (PMSM) using hybrid-type permanent magnet (PM) considering irreversible demagnetization. Here, the hybrid-type PM is defined as using both of neodymium PM (Nd-PM) and ferrite PM (Fe-PM) in a rotor. First, irreversible demagnetization of Fe-PM occurring by reversed magnetic field of Nd-PM is analyzed by using a finite-element method, when a rotor is inside or without a stator in order to improve reliability of PMSM using hybrid-type PM. Second, the optimized design considering demagnetization phenomenon is suggested for analyzing exactly output characteristics of the motor using hybrid-type PM. Finally, the prototypes based on proposed design are developed for evaluating the performance and demagnetization phenomenon through experiment.
Autors: Chae-Lim Jeong;Jin Hur;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Optimization of Vibration and Noise Characteristics of Skewed Permanent Brushless Direct Current Motor
Abstract:
In this paper, we analyze the vibration and noise characteristics of the basic and skewed models of permanent brushless direct current (BLDC) motor. The electromagnetic characteristics of the basic model are analyzed by the finite-element method. We analyzed the electromagnetic characteristics for skew angles from 15° to 25°. The skew angle was selected based on the analytical results of the electromagnetic characteristics. We analyzed the characteristics of radial force density for the basic model and the skewed model. The vibration and noise characteristics were analyzed through the mechanical harmonic analysis of the radial force and tangential force generated in the motor. We developed the basic and skewed models, and performed vibration and noise tests. The validity of this analysis is verified by comparing the simulation results with the actual test results of the model. Finally, for the optimal design of the BLDC motor considering vibration, the design variables such as teeth shoe length, yoke thickness, and teeth thickness were used. Based on the results of vibration analysis, the final model is derived and its performance is described.
Autors: Chang-Min Lee;Hyun-Soo Seol;Jae-yong Lee;Seung-Hwan Lee;Dong-Woo Kang;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Optimized Manipulation of the Network Characteristic Modes for Wideband Small Antenna Matching
Abstract:
Multiport antenna systems can be regarded as -port networks, which can be analyzed using the theory of network characteristic modes (NCMs). Due to the profound physical insights provided by an NCM, a desired antenna performance can be achieved by properly manipulating the modes through reactive loading at specified ports. This paper presents a new matching technique for an -port internally loaded small antenna. By combining the NCM with the differential evolution algorithm, optimal reactive load values can be calculated. These loads can manipulate the NCMs to match the antenna in a desired bandwidth. Unlike other matching techniques based on the NCM, the desired bandwidth is achieved through internal reactive loading without the need for an input matching network. Two examples of electrically small monopole antennas are studies. In both examples, we study the possibility to match the antennas in the GSM 900 band, and we further investigate the possibility to achieve wider bandwidths by varying the number of ports and the loading topologies based on the interpretation of the characteristic modes. The loaded antennas are wideband with a relatively stable radiation pattern and an efficiency higher than 90%. To confirm the theoretical results, a prototype is fabricated and measured.
Autors: Hussein Jaafar;Sylvain Collardey;Ala Sharaiha;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Nov 2017, volume: 65, issue:11, pages: 5757 - 5767
Publisher: IEEE
 
» Optimized Measurement Allocation for Power Distribution Systems Using Mixed Integer SDP
Abstract:
This paper presents a method for placement of metering systems in distribution grids taking into account the aspects of observability and state estimation accuracy. The measurement placement problem is conceptualized as the optimized allocation of a prespecified number of measurements in order to minimize the error variances of the state estimates either for observable or nonobservable networks. The proposed approach exploits the M-optimal experimental design technique to formulate the problem as a mixed integer semidefinite programming model. We demonstrate the efficacy of the proposed approach in terms of optimality and convergence speed through simulations on a 95-bus distribution grid.
Autors: Themistoklis C. Xygkis;George N. Korres;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Nov 2017, volume: 66, issue:11, pages: 2967 - 2976
Publisher: IEEE
 
» Optimized State Space Grids for Abstractions
Abstract:
The practical impact of abstraction-based controller synthesis methods is currently limited by the immense computational effort for obtaining abstractions. In this note we focus on a recently proposed method to compute abstractions whose state space is a cover of the state space of the plant by congruent hyper-intervals. The problem of how to choose the size of the hyper-intervals so as to obtain computable and useful abstractions is unsolved. This note provides a twofold contribution towards a solution. Firstly, we present a functional to predict the computational effort for the abstraction to be computed. Secondly, we propose a method for choosing the aspect ratio of the hyper-intervals when their volume is fixed. More precisely, we propose to choose the aspect ratio so as to minimize a predicted number of transitions of the abstraction to be computed, in order to reduce the computational effort. To this end, we derive a functional to predict the number of transitions in dependence of the aspect ratio. The functional is to be minimized subject to suitable constraints. We characterize the unique solvability of the respective optimization problem and prove that it transforms, under appropriate assumptions, into an equivalent convex problem with strictly convex objective. The latter problem can then be globally solved using standard numerical methods. We demonstrate our approach on an example.
Autors: Alexander Weber;Matthias Rungger;Gunther Reissig;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Nov 2017, volume: 62, issue:11, pages: 5816 - 5821
Publisher: IEEE
 
» Optimizing Spectrum Sensing Time With Adaptive Sensing Interval for Energy-Efficient CRSNs
Abstract:
The cognitive radio (CR) technology allows secondary users (SUs) to occupy the licensed bands opportunistically without causing interferences to primary users (PUs). SUs perform spectrum sensing to detect whether PUs are busy or idle. Therefore, spectrum sensing directly affects the performance of the PU protection and the secondary throughput. The sensing time is a critical parameter for spectrum sensing performance, and the optimum sensing time is a tradeoff between the spectrum sensing performance and the secondary throughput. In this paper, a novel spectrum sensing scheme is proposed to maximize both sensing accuracy and network energy efficiency. In order to provide a better protection for the PU, another spectrum sensing is adaptively performed according to the first sensing result. In other words, SU will perform spectrum sensing again to confirm that the PU is indeed idle when the first sensing result indicates the PU is idle. Due to the energy constraint in CR sensor networks, this adaptive sensing interval can also be adjusted according to the varying activity of the PU to maximize the network energy efficiency. Finally, our simulation study validates that the proposed scheme improves both the spectrum sensing performance and the energy efficiency compared with other existing methods.
Autors: Fanhua Kong;Jinsung Cho;Ben Lee;
Appeared in: IEEE Sensors Journal
Publication date: Nov 2017, volume: 17, issue:22, pages: 7578 - 7588
Publisher: IEEE
 
» Origami: A 803-GOp/s/W Convolutional Network Accelerator
Abstract:
An ever-increasing number of computer vision and image/video processing challenges are being approached using deep convolutional neural networks, obtaining state-of-the-art results in object recognition and detection, semantic segmentation, action recognition, optical flow, and super resolution. Hardware acceleration of these algorithms is essential to adopt these improvements in embedded and mobile computer vision systems. We present a new architecture, design, and implementation, as well as the first reported silicon measurements of such an accelerator, outperforming previous work in terms of power, area, and I/O efficiency. The manufactured device provides up to 196 GOp/s on 3.09 of silicon in UMC 65-nm technology and can achieve a power efficiency of 803 GOp/s/W. The massively reduced bandwidth requirements make it the first architecture scalable to TOp/s performance.
Autors: Lukas Cavigelli;Luca Benini;
Appeared in: IEEE Transactions on Circuits and Systems for Video Technology
Publication date: Nov 2017, volume: 27, issue:11, pages: 2461 - 2475
Publisher: IEEE
 
» Origin of Low-Energy Spurious Peaks in Spectroscopic Measurements With Silicon Detectors
Abstract:
When an uncollimated radioactive X-ray source illuminates a silicon PIN sensor, some ionizing events are generated in the nonimplanted gap between the active area of the sensor and the guard rings (GRs). Carriers can be collected by floating electrodes, i.e., electron accumulation layers at the silicon/oxide interface, and floating GRs. The crosstalk signals generated by these events create spurious peaks, replicas of the main peaks at either lower amplitude or of opposite polarity. We explain this phenomenon as crosstalk caused by charge collected on these floating electrodes, which can be analyzed by means of an extension of Ramo theorem.
Autors: Gabriele Giacomini;Alan Huber;Robert Redus;Sergio Rescia;
Appeared in: IEEE Transactions on Nuclear Science
Publication date: Nov 2017, volume: 64, issue:11, pages: 2883 - 2890
Publisher: IEEE
 
» Orthogonal Magnetic Field Analysis of a Double-Stator Linear-Rotary Permanent Magnet Motor With Orthogonally Arrayed Permanent Magnets
Abstract:
In this paper, a double-stator linear-rotary permanent magnet motor (DSLRPMM) for linear and/or rotary movement is presented. Since the two types of permanent magnets are orthogonally arrayed on the inner and outer surfaces of the mover core, respectively, the influences of the orthogonal magnetic field (OMF) on the motor electromagnetic characteristics cannot be ignored. Based on the 3-D finite-element method (FEM), the OMF in the motor and the iron core magnetization characteristics are investigated, and a test device is constructed to verify the results obtained by the theoretical analysis and 3-D finite-element analysis (FEA). On the basis of the measured data, the 2-D FEM is employed to analyze the electromagnetic characteristics of the DSLRPMM, including flux density, flux linkage, back-electromotive force, detent force, and cogging torque. The results are compared with that obtained by the 3-D FEA, and they are in agreement. Moreover, a prototype is built and tested. The experimental results verify the correctness of the predictions.
Autors: Lei Xu;Mingyao Lin;Xinghe Fu;Xiaoyong Zhu;Chao Zhang;Wenye Wu;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Outage Performance for Cooperative NOMA Transmission with an AF Relay
Abstract:
This letter studies the outage performance of cooperative non-orthogonal multiple access (NOMA) network by adopting an amplify-and-forward relay. An accurate approximation for the outage probability is derived and then the asymptotic behaviors are investigated. It is revealed that cooperative NOMA achieves the same diversity order and the superior coding gain compared to cooperative orthogonal multiple access. It is also shown that the outage performance improves when the distance between the relay and indirect link user decreases, assuming the smaller transmit power of relay than the base station.
Autors: Xuesong Liang;Yongpeng Wu;Derrick Wing Kwan Ng;Yiping Zuo;Shi Jin;Hongbo Zhu;
Appeared in: IEEE Communications Letters
Publication date: Nov 2017, volume: 21, issue:11, pages: 2428 - 2431
Publisher: IEEE
 
» Overview of Passive Optical Multispectral and Hyperspectral Image Simulation Techniques
Abstract:
The simulation of optical images can play key roles in the development of new instruments, the quantitative evaluation of algorithms and in the training of both image analysis software and human analysts. Methods for image simulation include surrogate data collections, operations on empirical imagery, statistical generation techniques, and full physical modeling approaches. Each method offers advantages or disadvantages in terms of time, cost, and realism. Current state of the art suggests three-dimensional radiative transfer models capture most of the significant characteristics of real imagery and find valuable use in system development and evaluation programs. Emerging computational power available from multithreading, graphical processing units, and techniques from deep learning will continue to enable even more realistic simulations in the near future.
Autors: Sanghui Han;John P. Kerekes;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Nov 2017, volume: 10, issue:11, pages: 4794 - 4804
Publisher: IEEE
 
» Pairing and Power Allocation for Downlink Nonorthogonal Multiple Access Systems
Abstract:
In this paper, a greedy-search-based user pairing and selection method as well as an optimal power allocation approach is proposed to maximize the weighted sum rate of a downlink nonorthogonal multiple access (NOMA) system. The NOMA system consists of one base station and multiple users. By exploiting superposition coding and successive interference cancellation techniques at the receiver, multiple users can be multiplexed into transmit power domain, and then nonorthogonally scheduled for transmission on the same spectrum resources. The proposed greedy-search-based user pairing method has low computational complexity and the power allocation method is shown to be equivalent to a weighted minimum mean square error based problem, which is solved using an iterative procedure. The subproblem in each step of the iteration has a closed-form solution. Also, the convergence of the iteration is proved. Simulation results show that the proposed method can significantly improve the sum rate of the system over the other methods.
Autors: Lanjie Shi;Bo Li;Haihua Chen;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Nov 2017, volume: 66, issue:11, pages: 10084 - 10091
Publisher: IEEE
 
» Pairwise Stochastic Bounded Confidence Opinion Dynamics: Heavy Tails and Stability
Abstract:
Unlike traditional graph-based linear dynamics, where agents exchange opinions with their neighbors in a static social graph regardless of their differences in opinions, the bounded confidence opinion dynamics models exchange between agents with similar opinions. We generalize the bounded confidence opinion dynamics model by incorporating pairwise stochastic interactions, probabilistic influencing based on opinion differences and the self or endogenous evolutions of the agent opinions, which are represented by random processes. The opinion exchanges resulting from influencing have pairwise contraction effects, whereas endogenous motions have an expansive effect, for instance, of a diffusive nature. We analytically characterize the conditions under which this stochastic dynamics is stable in an appropriate sense. In the diffusive case, the presence of heavy tailed influence functions with a Pareto exponent of 2 is critical for stability (for a pair of agents an influence function maps opinion differences to probabilities of influence). Moreover, this model sheds light on dynamics that combine aspects of graph-based and bounded confidence dynamics.
Autors: François Baccelli;Avhishek Chatterjee;Sriram Vishwanath;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Nov 2017, volume: 62, issue:11, pages: 5678 - 5693
Publisher: IEEE
 
» Parameter Calculation and Analysis of a Novel Wind Power Generator
Abstract:
Compared with the commonly used generators, the brushless doubly fed generator (BDFG) has a commercial potential for wind power generation due to its inherent characteristics. In this paper, a novel BDFG with hybrid rotor is proposed and its structural features and operation principle are presented. Meanwhile, the performance of the proposed BDFG is analyzed in comparison with the BDFG using a radial laminated magnetic barrier rotor. Furthermore, due to the complexity of the magnetic field and the particularity of the structure, the calculation and analysis of the parameters, especially the inductance, are extremely important for the performance analysis of the proposed BDFG. Therefore, an inductance calculation method based on modified winding function is investigated. For accurate inductance calculation, the effects of magnetic layers and cage bars on the air-gap permeance of the proposed hybrid rotor are both considered. Tests are performed on a 25 kW prototype machine to verify the performance of the proposed BDFG. The experimental results show the correctness and feasibility of the proposed inductance calculation method.
Autors: Siyang Yu;Fengge Zhang;Hao Wang;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 7
Publisher: IEEE
 
» Parametric Optimum Design of a Graphene-Based Thermionic Energy Converter
Abstract:
A new model of the thermionic energy converter (TEC) configured with the graphene-based cathode is proposed, which includes the thermal radiation between the cathode and the anode electrodes and the heat losses from the anode to the environment. Analytic expressions for the power output density and efficiency of the TEC are derived. The performance characteristics of the TEC are analyzed by numerical calculations. It is found that the maximum efficiency and power density can, respectively, reach 30% and when the TEC is operated between the two heat reservoirs at temperatures 1500 and 300 K. In addition, the optimum regions of the efficiency, power density, voltage output, electric current, and anode temperature are determined. The maximum efficiency and power density of the graphene-based TEC operated at different temperatures are calculated and compared with those of the metal-based TEC. It shows that the graphene-based TEC operated at 1200–1800 K displays the better performance than the metal-based TEC. The results obtained here may provide guidance for the appropriate selection of electrode materials and optimum design of practical TEC devices.
Autors: Xin Zhang;Yuzhuo Pan;Jincan Chen;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Nov 2017, volume: 64, issue:11, pages: 4594 - 4598
Publisher: IEEE
 
» Partial Overlapped Time-Shifted Pilots for Massive MIMO Systems
Abstract:
This letter proposes a partial-time-shifted pilot scheme to find a better tradeoff between the user accommodation and orthogonality of pilots for the massive multiple-input multiple-output system. To this end, the pilot symbols rather than the pilot sequences are applied. In addition, the neighboring cells are allowed to transmit the pilot signals using the overlapped symbol periods. Despite the stronger interference, the larger user accommodation as well as the near-far effect incurred by using the pilot symbols can contribute to the higher sum transmission rates for both the uplink and downlink cases.
Autors: Wenson Chang;Yun-Kuei Hua;Shu-Fong Liao;
Appeared in: IEEE Communications Letters
Publication date: Nov 2017, volume: 21, issue:11, pages: 2480 - 2483
Publisher: IEEE
 
» Particle Adsorption Onto Si-Based Wafers in Ultrapure Water; Its Mechanism and Effect of Carbon Dioxide
Abstract:
Ultrapure water contains several kinds of contaminants. In particular, we paid much attention to particles and investigated particles adsorption onto Si-based wafers. We succeed in making a model through two experiments. One is to study an impact of spin cleaning parameters on particle adsorption, and the other is to study that of such impurities as urea, hydrogen peroxide, carbon dioxide, and so on. The former test succeeded in quantitatively estimating the magnitude of each degree of influence to some extent assuming that there are roughly two steps of attaching particles to the wafer, namely adsorption equilibrium during rinsing and residuals during drying. The latter is to confirm that substances that are likely to be mixed in ultrapure water do not affect particle adsorption in the future manufacturing process. We concluded that we need to pay attention to carbon dioxide especially in this system.
Autors: Koji Nakata;Takeo Fukui;Tatsuo Nagai;
Appeared in: IEEE Transactions on Semiconductor Manufacturing
Publication date: Nov 2017, volume: 30, issue:4, pages: 371 - 376
Publisher: IEEE
 
» Passively Track WiFi Users With an Enhanced Particle Filter Using Power-Based Ranging
Abstract:
Passive positioning systems produce user location information for third-party providers of positioning services. In this paper, we provide a passive tracking system for WiFi signals with an enhanced range-only particle filter using fine-grained power. Our proposed particle filter, WVT-bootstrap particle filter, provides improved observation likelihood and is equipped with a single coordinated turn model to address the challenges in passive positioning. The anchor nodes for WiFi signal sniffing use software defined radio techniques to extract channel state information for multipath mitigation and a non-linear regression method is used for the path-loss model. Our tracking system produces measured positioning errors that, in the 80th percentile, are equal to or less than 2 m; this represents a 33% improvement over the traditional bootstrap particle filter. Additionally, it requires (0.12 s for 1000 particles) only half of the computation efforts as a multi-model particle filter.
Autors: Zan Li;Torsten Braun;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Nov 2017, volume: 16, issue:11, pages: 7305 - 7318
Publisher: IEEE
 
» Past forward: world's most famous teapot [Past forward]
Abstract:
Do you recognize this teapot? Tea boffins might recognize it as a Melitta product. Computer graphics people, though, know this as the "Utah teapot." In the mid-1970s, Martin Newell created an impressive 3D model of the teapot for his Ph.D. work at the University of Utah. Other researchers adopted the iconic teapot to develop new graphics hardware and software. It also made cameo appearances in Toy Story, Monsters, Inc., and “The Simpsons,” eventually earning it the moniker of "World' Most Famous Teapot."
Autors: David C. Brock;
Appeared in: IEEE Spectrum
Publication date: Nov 2017, volume: 54, issue:11, pages: 68 - 68
Publisher: IEEE
 
» Patching the internet of things
Abstract:
ON 21 OCTOBER OF LAST YEAR, a variety of major websites—including those of Twitter, PayPal, Spotify, Netflix, The New York Times, and The Wall Street Journal—stopped working. The cause was a distributed denial-of-service attack, not on these websites themselves but on the provider they and many others used to support the Domain Name System, or DNS, which translates the name of the site into its numerical address on the Internet. The DNS provider in this case was a company called Dyn, whose servers were barraged by so many fake requests for DNS lookups that they couldn’t answer the real ones.
Autors: Sandip Ray;Abhishek Basak;Swarup Bhunia;
Appeared in: IEEE Spectrum
Publication date: Nov 2017, volume: 54, issue:11, pages: 30 - 35
Publisher: IEEE
 
» Patient-Specific Left Ventricular Flow Simulations From Transthoracic Echocardiography: Robustness Evaluation and Validation Against Ultrasound Doppler and Magnetic Resonance Imaging
Abstract:
The combination of medical imaging with computational fluid dynamics (CFD) has enabled the study of 3-D blood flow on a patient-specific level. However, with models based on gated high-resolution data, the study of transient flows, and any model implementation into routine cardiac care, is challenging. This paper presents a novel pathway for patient-specific CFD modelling of the left ventricle (LV), using 4-D transthoracic echocardiography (TTE) as input modality. To evaluate the clinical usability, two sub-studies were performed. First, a robustness evaluation was performed, where repeated models with alternating input variables were generated for six subjects and changes in simulated output quantified. Second, a validation study was carried out, where the pathway accuracy was evaluated against pulsed-wave Doppler (100 subjects), and 2-D through-plane phase-contrast magnetic resonance imaging measurements over seven intraventricular planes (6 subjects). The robustness evaluation indicated a model deviation of <12%, with highest regional and temporal deviations at apical segments and at peak systole, respectively. The validation study showed an error of <11% (velocities <10 cm/s) for all subjects, with no significant regional or temporal differences observed. With the patient-specific pathway shown to provide robust output with high accuracy, and with the pathway dependent only on 4-D TTE, the method has a high potential to be used within future clinical studies on 3-D intraventricular flow patterns. To this, future model developments in the form of e.g., anatomically accurate LV valves may further enhance the clinical value of the simulations.
Autors: David Larsson;Jeannette H. Spühler;Sven Petersson;Tim Nordenfur;Massimiliano Colarieti-Tosti;Johan Hoffman;Reidar Winter;Matilda Larsson;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Nov 2017, volume: 36, issue:11, pages: 2261 - 2275
Publisher: IEEE
 
» Patterns for Distributed Real-Time Stream Processing
Abstract:
In recent years, big data systems have become an active area of research and development. Stream processing is one of the potential application scenarios of big data systems where the goal is to process a continuous, high velocity flow of information items. High frequency trading (HFT) in stock markets or trending topic detection in Twitter are some examples of stream processing applications. In some cases (like, for instance, in HFT), these applications have end-to-end quality-of-service requirements and may benefit from the usage of real-time techniques. Taking this into account, the present article analyzes, from the point of view of real-time systems, a set of patterns that can be used when implementing a stream processing application. For each pattern, we discuss its advantages and disadvantages, as well as its impact in application performance, measured as response time, maximum input frequency and changes in utilization demands due to the pattern.
Autors: Pablo Basanta-Val;Norberto Fernández-García;Luis Sánchez-Fernández;Jesus Arias-Fisteus;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Nov 2017, volume: 28, issue:11, pages: 3243 - 3257
Publisher: IEEE
 
» Paving the Way: A Future Without Inertia Is Closer Than You Think
Abstract:
Unless you have been hibernating in a remote cave for the past decade, you will have noticed the explosion of variable renewable generation. Wind power and solar photovoltaics (PVs) have been the subject of dozens of articles, just within the pages of IEEE Power & Energy Magazine. Charts illustrating relentless growth, such as the example from the United States shown in Figure 1 with futures tending toward 100% renewable energy, are common. This figure, provided by the National Renewable Energy Laboratory (NREL), reflects a low-cost, high-renewable projection scenario.
Autors: Thomas Ackermann;Thibault Prevost;Vijay Vittal;Andrew J. Roscoe;Julia Matevosyan;Nicholas Miller;
Appeared in: IEEE Power and Energy Magazine
Publication date: Nov 2017, volume: 15, issue:6, pages: 61 - 69
Publisher: IEEE
 
» PaWaIC-PSAOFDTD: Particle-Wave Interaction Code With Pseudospectral Arbitrary-Order Accurate Temporal and Spatial Derivatives FDTD Technique for Helix TWT
Abstract:
Numerical modeling and simulations have been essential for rapid developments of vacuum electronic devices. Pseudospectral solvers have interesting capabilities to be considered, but up to now, they have not been extensively used for the modeling of vacuum tubes. In this paper, we present a novel 1-D time-domain numerical scheme which has the great aptitude of considering geometrical dispersion characteristic of helix traveling-wave tube (TWT) in time domain. This ability is interesting for one-run investigation of time-domain events such as pulse excitation of wideband tubes. The numerical model is extended to have simultaneously arbitrary order of accuracy in space and time derivations; so we achieve a code which presents a very low level of numerical dispersion error, without forcing a notable numerical calculation burden. To validate our new simulation tool, we have studied the experimental results of a TWT product, and successfully compared the results to the impulse response of the new 1-D code.
Autors: Amir Setayesh;Mohammad Sadegh Abrishamian;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Nov 2017, volume: 64, issue:11, pages: 4706 - 4714
Publisher: IEEE
 
» People, Technologies, and Organizations Interactions in a Social Commerce Era
Abstract:
Social commerce, a powerful combination of customer-oriented social computing technologies and new commercial features, is having an increasing impact on e-commerce, potentially generating substantial economic benefits. Drawing on socio-technical theory, this study establishes a research framework to help understand the social and technical factors affecting consumers’ intention to purchase on social commerce sites. Our results demonstrate that familiarity, user experience, learning and training, and social commerce constructs all have a positive effect on consumers’ perceptions of ease of use and usefulness, thereby enhancing their trust and intention to purchase. For systems designers and engineers, our results highlight the importance of social commerce features for building consumers’ trust of social commerce sites and supporting their intention to purchase.
Autors: Nick Hajli;Yichuan Wang;Mina Tajvidi;M. Sam Hajli;
Appeared in: IEEE Transactions on Engineering Management
Publication date: Nov 2017, volume: 64, issue:4, pages: 594 - 604
Publisher: IEEE
 
» Perfectly Secure Index Coding
Abstract:
In this paper, we investigate the index coding problem in the presence of an eavesdropper. Messages are to be sent from one transmitter to a number of legitimate receivers who have side information about the messages, and share a set of secret keys with the transmitter. To do this, the transmitter communicates to the legitimate receivers the public code , which is also heard by the eavesdropper. We assume perfect secrecy, meaning that the eavesdropper should not be able to retrieve any information about the message set from the public communication. We study the minimum key lengths for zero-error and perfectly secure index coding problem. On one hand, this problem is a generalization of the index coding problem (and thus a difficult one). On the other hand, it is a generalization of the Shannon’s cipher system. We show that a generalization of Shannon’s one-time pad strategy is optimal up to a multiplicative constant, meaning that it obtains the entire boundary of the cone formed by looking at the secure rate region from the origin. This shows the optimality of the generalized one-time pad for minimizing the consumption of shared secret keys per message bits, when public communication is free (the transmitter is not charged for the rate of the public communication). Finally, we consider relaxation of the perfect secrecy and zero-error constraints to weak secrecy and asymptotically vanishing probability of error, and provide a secure version of the result, obtained by Langberg and Effros, on the equivalence of zero-error and -error regions in the conventional index coding problem.
Autors: Mohammad Mahdi Mojahedian;Mohammad Reza Aref;Amin Gohari;
Appeared in: IEEE Transactions on Information Theory
Publication date: Nov 2017, volume: 63, issue:11, pages: 7382 - 7395
Publisher: IEEE
 
» Performance Analysis for Lossy-Forward Relaying Over Nakagami- $m$ Fading Channels
Abstract:
We investigate the performance of three-node lossy-forward (LF) relaying over independent block Nakagami- fading channels. Based on the theorem of source coding with side information, the exact outage probability expression for arbitrary values of the shape factor is derived under the assumptions of both the Gaussian codebook capacity and the constellation constrained capacity. The difference in outage probability between the two codebook models of capacity is found to be very minor. Furthermore, an accurate high signal-to-noise ratio approximation for the outage probability is obtained. It clearly identifies the equivalent diversity order and coding gain of the LF relaying. It is shown that the LF relaying is superior to conventional decode-and-forward relaying in terms of the outage probability and the -outage achievable rate. Moreover, with the LF relaying, the optimal location for the relay (R), which minimizes the outage probability, is found to be the point having same distance to the source (S) and the destination (D) when the S-R and R-D links experience the same level of fading. The accuracy of the analytical results is verified by a series of Monte Carlo simulations.
Autors: Shen Qian;Xiaobo Zhou;Xin He;Jiguang He;Markku Juntti;Tad Matsumoto;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Nov 2017, volume: 66, issue:11, pages: 10035 - 10043
Publisher: IEEE
 
» Performance Analysis of Non-Regenerative Massive-MIMO-NOMA Relay Systems for 5G
Abstract:
The non-regenerative massive multi-input-multi-output (MIMO) non-orthogonal multiple access (NOMA) relay systems are introduced in this paper. The NOMA is invoked with a superposition coding technique at the transmitter and successive interference cancellation (SIC) technique at the receiver. In addition, a maximum mean square error-SIC receiver design is adopted. With the aid of deterministic equivalent and matrix analysis tools, a closed-form expression of the signal to interference plus noise ratio (SINR) is derived. To characterize the performance of the considered systems, closed-form expressions of the capacity and sum rate are further obtained based on the derived SINR expression. Insights from the derived analytical results demonstrate that the ratio between the transmitter antenna number and the relay number is a dominate factor of the system performance. Afterward, the correctness of the derived expressions are verified by the Monte Carlo simulations with numerical results. Simulation results also illustrate that: 1) the transmitter antenna, averaged power value, and user number display the positive correlations on the capacity and sum rate performances, whereas the relay number displays a negative correlation on the performance and 2) the combined massive-MIMO-NOMA scheme is capable of achieving higher capacity performance compared with the conventional MIMO-NOMA, relay-assisted NOMA, and massive-MIMO orthogonal multiple access (OMA) scheme.
Autors: Di Zhang;Yuanwei Liu;Zhiguo Ding;Zhenyu Zhou;Arumugam Nallanathan;Takuro Sato;
Appeared in: IEEE Transactions on Communications
Publication date: Nov 2017, volume: 65, issue:11, pages: 4777 - 4790
Publisher: IEEE
 
» Performance Analysis of Nonorthogonal Multiple Access for Downlink Networks With Antenna Selection Over Nakagami-m Fading Channels
Abstract:
We investigate the system performance of a nonorthogonal multiple access (NOMA) based downlink amplify-and-forward relay network over Nakagami- fading channels with imperfect channel state information, where the base station and all users are provided with multiple antennas, while the relay is equipped with a single antenna. Two special conditions of interest (e.g., Nakagami-1, i.e., Rayleigh and Nakagami-2) are analyzed, and closed-form expression for the system outage probability is derived. Moreover, tight lower and upper bounds of the outage probability, and the outage probability in the high signal-to-interference-and-noise ratio regime, i.e., in the presence of error floor, which exists due to the channel estimation errors, are obtained. Finally, computer simulations are conducted to verify the accuracy of the numerical analysis and to confirm the superiority of the antenna selection and NOMA scheme.
Autors: Yangyang Zhang;Jianhua Ge;Erchin Serpedin;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Nov 2017, volume: 66, issue:11, pages: 10590 - 10594
Publisher: IEEE
 
» Performance Analysis of Reconfigurable Bandpass Filters With Continuously Tunable Center Frequency and Bandwidth
Abstract:
This paper presents a comparison and performance evaluation of three different technologies for the implementation of tunable filters utilizing semiconductor varactors, commercially available barium strontium titanate (BST) thin film and screen-printed BST thick-film varactors. To identify the most suitable technology for applications in low power receiving up to high-power transmitting stages, the performance evaluation is carried out with the same tunable hairpin filter design. While the center frequency of the proposed tunable filter structure is tuned by varactors loading the filter resonators, the bandwidth is controlled by coupling varactors between adjacent resonators. The filters are designed for a center frequency range from 700 MHz to 1 GHz and for bandwidth tuning from 60 to 150 MHz. The tunable filters are evaluated and compared with regard to their tunability, quality factor, linearity (intermodulation products of third order), and power handling capability. In conclusion, the tunable hairpin filter based on semiconductor varactor diodes offers the largest center frequency tuning range of 390 MHz with a transmission between −1.5 and −7 dB, whereas the BST thin- and thick-film-varactors-based filters exhibit high linearity with an IIP3 between 39 and 60 dBm. Moreover, large signal characterization reveals that the BST thick-film-varactors-based filter structure has the best power handling capability of up to 41dBm.
Autors: Christian Schuster;Alex Wiens;Florian Schmidt;Matthias Nickel;Martin Schüßler;Rolf Jakoby;Holger Maune;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Nov 2017, volume: 65, issue:11, pages: 4572 - 4583
Publisher: IEEE
 
» Performance Analysis of Two-Tier HetNets With Massive MIMO and Nonuniformly Small Cell Deployment
Abstract:
The performance of a coordinated multipoint transmission for massive multiple-input multiple-output (MIMO) heterogeneous networks with practical deployment is investigated. The active small cell base stations outside the inner region of macrocell base stations are used to improve the performance of macrocell edge users. Based on the stochastic geometry approach, the spectral efficiency (SE) and energy efficiency (EE) of the proposed scheme are analyzed. An alternating optimal algorithm is employed to solve the EE maximization problem effectively. The impacts of the small cell density, inner region size, and massive MIMO on the network performance are explicitly examined. Moreover, by approximating the interference distribution by moment matching with the Gamma distribution, the coverage probability of the two-tier HetNet is also studied. Numerical results show that the proposed HetNet generally outperforms the conventional maximum receive power association scheme and it provides a potential solution to achieve high SE and EE performance.
Autors: Tuong Xuan Tran;Kah Chan Teh;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Nov 2017, volume: 66, issue:11, pages: 10044 - 10054
Publisher: IEEE
 
» Performance and Optimization Study of a Novel Compact Permanent-Magnet-Biased Fault Current Limiter
Abstract:
The permanent-magnet-biasing saturated core fault current limiter (PMFCL) is one of the most promising devices to limit the fault current. To improve the biasing ability of permanent-magnets (PMs) and reduce the cost of PMFCL, this paper proposes a novel compact permanent-magnet-biased fault current limiter (CPMFCL). The three-limb structure can reduce the size and cost; the optimal small-section structure can improve the biasing ability of PMs and reduce the usage amount of PMs. First, the principle, equivalent magnetic circuit, and small-section optimized structure are introduced. To validate the principle and performance of CPMFCL, various finite element analysis simulation and optimization study are performed in Maxwell-3D. A 220 V/10 A CPMFCL prototype is designed and tested. The simulation and experimental results demonstrate that, compared with traditional PMFCLs, the CPMFCL has the advantages of smaller size, better biasing capacity of PMs, lower possibility of demagnetization, and excellent fault clipping performance.
Autors: Liangliang Wei;Baichao Chen;Jiaxin Yuan;Cuihua Tian;Yongheng Zhong;Xiang Li;Yanhui Gao;Kazuhiro Muramatsu;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Performance and Variability Analysis of SiNW 6T-SRAM Cell Using Compact Model With Parasitics
Abstract:
In this paper, we analyze stability metrics [e.g., read, write noise margins (WNM), and access time], geometrical variability, and layout area optimization of silicon nanowire field effect transistor (SiNW FET) based 6T SRAM with multiwire sizing technique. The SRAM cell analyzed in this paper is based on the TCAD and experimentally verified SiNW FET Verilog-A compact model with parasitics. The different NW SRAM design configurations (e.g., , , etc., denotes the number of wires in pull-up, access, and pull-down transistors, respectively) are investigated. The read static noise margin and read access time (RAT) are improved up to ∼38% and ∼18% with little pay of WNM by ∼9% (↓), write access time (WAT) ∼33% (↑) in configuration compared to . Other configuration such as possess more improvements upto ∼55%, ∼20% in RNM, RAT with WNM (↓∼21%), and WAT (∼44%↑) compare to at the expense of more layout area. Finally, the impact of geometrica- variability including length, radius, and oxide thickness on the read and write stability using N-curve is examined. It is found that the static read and write stability is less susceptible to variability at nominal supply voltage. However, it is very sensitive to the voltage scaling in which read (write) voltage margin varies upto ∼2–3% (∼2.5–4.5%) and read (write) current margin varies upto ∼18% (∼35%) depending upon the design configurations. Among all design configurations, is the better configuration for considering overall performances such as write stability, speed, layout area, and variability tolerance.
Autors: Om Prakash;Satish Maheshwaram;Mohit Sharma;Anand Bulusu;Sanjeev K. Manhas;
Appeared in: IEEE Transactions on Nanotechnology
Publication date: Nov 2017, volume: 16, issue:6, pages: 965 - 973
Publisher: IEEE
 
» Performance Assessment of Vessel Dynamic Models for Long-Term Prediction Using Heterogeneous Data
Abstract:
Ship traffic monitoring is a foundation for many maritime security domains, and monitoring system specifications underscore the necessity to track vessels beyond territorial waters. However, vessels in open seas are seldom continuously observed. Thus, the problem of long-term vessel prediction becomes crucial. This paper focuses attention on the performance assessment of the Ornstein-Uhlenbeck (OU) model for long-term vessel prediction, compared with usual and well-established nearly constant velocity (NCV) model. Heterogeneous data, such as automatic identification system (AIS) data, high-frequency surface wave radar data, and synthetic aperture radar data, are exploited to this aim. Two different association procedures are also presented to cue dwells in case of gaps in the transmission of AIS messages. Suitable metrics have been introduced for the assessment. Considerable advantages of the OU model are pointed out with respect to the NCV model.
Autors: Gemine Vivone;Leonardo M. Millefiori;Paolo Braca;Peter Willett;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Nov 2017, volume: 55, issue:11, pages: 6533 - 6546
Publisher: IEEE
 
» Performance Bounds for Parameter Estimation under Misspecified Models: Fundamental Findings and Applications
Abstract:
Inferring information from a set of acquired data is the main objective of any signal processing (SP) method. The common problem of estimating the value of a vector of parameters from a set of noisy measurements is at the core of a plethora of scientific and technological advances in recent decades, including wireless communications, radar and sonar, biomedicine, image processing, and seismology.
Autors: Stefano Fortunati;Fulvio Gini;Maria S. Greco;Christ D. Richmond;
Appeared in: IEEE Signal Processing Magazine
Publication date: Nov 2017, volume: 34, issue:6, pages: 142 - 157
Publisher: IEEE
 
» Performance Comparison Between Reflection Symmetry Metric and Product of Multilook Amplitudes for Ship Detection in Dual-Polarization SAR Images
Abstract:
The reflection symmetry metric (RSM) and product of multilook amplitudes (PMA) detectors, which were proposed recently, have been demonstrated to be promising methods for processing dual-polarimetric synthetic aperture radar (SAR) data for ship detection. The improvements in ship detection performance by using the RSM, compared to that using the PMA, are investigated in this paper. As the ship-sea contrast (or the signal-clutter-ratio, SCR) is a central index to assess the performance of a detection method, the SCRs in the RSM and PMA are first defined and compared. Next, a theoretical explanation for why the RSM outperforms the PMA in detection performance is provided. The detection performance is then characterized by calculating the receiver operating characteristic (ROC) curves. The preliminary experimental results performed on measured RADARSAT-2, ALOS-PALSAR, and NASA/JPL AIRSAR images verify the accuracy of the theoretical analysis.
Autors: Gui Gao;Gongtao Shi;Gaosheng Li;Jianghua Cheng;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Nov 2017, volume: 10, issue:11, pages: 5026 - 5038
Publisher: IEEE
 
» Performance Comparison Between the Normal-Conducting Magnet and the Superconducting Magnet in LSM for High-Speed Propulsion
Abstract:
On the wheel-rail supported hybrid railway system, the linear synchronous motor (LSM) for very high-speed transit must be a system that can maintain a large air gap, and the maximum vertical displacement must be taken into consideration in designing the LSM. As such, this paper designs two small-scale LSM models that produce equal output power—one with the normal-conducting magnet and the other with the superconducting magnet. In addition, this paper conducts a comparative analysis of the various characteristics by applying the electromagnetic numerical analysis method. Furthermore, this paper manufactures two small-scale LSM prototypes which have the normal-conducting magnet and the superconducting magnet, while also conducting a no-load and load test. Through such comparisons, this paper attempts to verify the characteristic values of the two models.
Autors: Chan-Bae Park;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 6
Publisher: IEEE
 
» Performance Comparison of ETT- and LTT-Based Pulse Power Crowbar Switch
Abstract:
High-voltage high-power pulse switches are built with semiconductor devices, preferably thyristor, due to the superior performance that they offer. Triggering methods classify the thyristor as electrically triggered thyristor (ETT) and light triggered thyristor (LTT). Due to the specialized gate constructions and many build-in protections, the cost of LTT is much higher than ETT. The operating modes in applications, such as crowbar, do not require all these build-in protections. In this paper, the operation of a crowbar is analyzed, and the build-in protections of LTT are reviewed. This paper proposes three experiments for the design selection of thyristor, between ETT and LTT, for crowbar applications. The experiments cover the electrical performance as well as electromagnetic emissions in a 10-kV, 1-kA crowbar built with both ETT as well as LTT, which can be used to benchmark the performance of the crowbar circuit. From the three experiments, the performance of ETT-based crowbar is found to be comparable with LTT-based crowbar. Based on the experiments carried out with the proposed benchmarking approaches, this paper shows that ETT-based crowbar is a cost-effective solution for crowbar applications.
Autors: T. G. Subhash Joshi;Vinod John;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Nov 2017, volume: 45, issue:11, pages: 2994 - 3000
Publisher: IEEE
 
» Performance evaluation of XG-PON based mobile front-haul transport in cloud-RAN architecture
Abstract:
Time division multiplexing passive optical network (TDM-PON) technologies are viewed as an attractive solution for flexible and cost-efficient mobile front-haul for cloud radio access network (C-RAN) architecture. However, it is a challenge for TDM-PONs to meet the strict latency requirement of mobile front-haul in C-RAN because they use a dynamic bandwidth allocation (DBA) mechanism to manage upstream traffic. The latency issue of TDM-PON based mobile front-haul has been extensively investigated in the literature with particular focus on IEEE TDM-PON (e.g., 10G-EPON). However, ITU TDM-PONs such as XG-PON and XGS-PON have not yet even been explored in the context of mobile front-haul. To cover this gap, we first evaluate the performance of two recently proposed XG-PON-standard-compliant DBAs, namely, group-assured GIANT (gGIANT) and round-robin DBA (RR-DBA), over simulated mobile front-haul traffic. We conclude based on our evaluation that neither RR-DBA nor gGIANT satisfies the delay required for mobile front-haul. Therefore, we propose an optimized DBA known as optimized round-robin (optimized-RR) that support front-hauling over XG-PONs. The performance evaluation of our optimized DBA against gGIANT and RR-DBA shows significant improvement in upstream delay and utilization as well as lower packet loss and jitter for front-haul uplink traffic transmitted via XG-PON in virtualized C-RAN architecture.
Autors: Ahmed Mohammed Mikaeil;Weisheng Hu;Tong Ye;Syed Baqar Hussain;
Appeared in: IEEE/OSA Journal of Optical Communications and Networking
Publication date: Nov 2017, volume: 9, issue:11, pages: 984 - 994
Publisher: IEEE
 
» Performance Factor Comparison of Nanocrystalline, Amorphous, and Crystalline Soft Magnetic Materials for Medium-Frequency Applications
Abstract:
The efficiency of electromagnetic devices is influenced by the losses of the applied soft magnetic material. Different structured materials are available. Choosing the most appropriate material for a medium-frequency application is not intuitive. Electromagnetic circuits of power transformers or electric motors are usually made of conventional silicon–iron sheets. Higher power densities can be achieved by an increased operational frequency, but the loss density increases with higher frequencies as well. Amorphous and nanocrystalline materials benefit from reduced eddy current losses at higher frequencies. In this paper, a performance factor is evaluated to determine the suitability of each material in a frequency range up to 10 kHz. The geometric parameters of electromagnetic designs depend on the applied material. A performance factor may help to identify the most appropriate material at a specific frequency. The final application is a medium-frequency transformer. The losses of the magnetic materials are measured by using standardized measurement equipment such as single sheet tester or Epstein frame. A semi-physical iron-loss model is used to describe the measured losses. These results are used to determine the performance factor.
Autors: Tobias Kauder;Kay Hameyer;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Performance Impact of Idle Mode Capability on Dense Small Cell Networks
Abstract:
Very recent studies showed that in a fully loaded dense small cell network (SCN), the coverage probability performance will continuously decrease with the network densification. Such new results were captured in IEEE ComSoc Technology News with an alarming title of “Will Densification Be the Death of 5G?” In this paper, we revisit this issue from more practical views of realistic network deployment, such as a finite number of active base stations (BSs) and user equipments (UEs), a decreasing BS transmission power with the network densification, etc. Particularly, in dense SCNs, due to an oversupply of BSs with respect to UEs, a large number of BSs can be put into idle modes without signal transmission, if there is no active UE within their coverage areas. Setting those BSs into idle modes mitigates unnecessary intercell interference and reduces energy consumption. In this paper, we investigate the performance impact of such BS idle mode capability (IMC) on dense SCNs. Different from existing work, we consider a realistic path loss model incorporating both line-of-sight (LoS) and non-LoS transmissions. Moreover, we obtain analytical results for the coverage probability, the area spectral efficiency and the energy efficiency (EE) performance for SCNs with the BS IMC and show that the performance impact of the IMC on dense SCNs is significant. As the BS density surpasses the UE density in dense SCNs, the coverage probability will continuously increase toward one, addressing previous concerns on “the death of 5G”. Finally, the performance improvement in terms of the EE performance is also investigated for dense SCNs using practical energy models developed in the Green-Touch project.
Autors: Ming Ding;David López-Pérez;Guoqiang Mao;Zihuai Lin;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Nov 2017, volume: 66, issue:11, pages: 10446 - 10460
Publisher: IEEE
 
» Performance Improvement of p-Channel Tin Monoxide Transistors With a Solution-Processed Zirconium Oxide Gate Dielectric
Abstract:
This letter reports the fabrication of p-channel tin monoxide (SnO) thin-film transistors (TFTs) with a high-permittivity zirconium oxide (ZrO2) gate insulator film, which were prepared by a low-cost spin-cast method. The spin-cast ZrO2 dielectrics exhibit a low leakage current density of A/cm2 at 1 MV/cm. Introducing the ZrO2 dielectric in top-type SnO TFTs allows for a reduction in the driving gate voltage range from 80 to 10 V, as compared with devices with a thermal SiO2 gate insulator. Additionally, a high field-effect mobility of 2.5 cm2/Vs and an of were preserved.
Autors: Azida Azmi;Jiwon Lee;Tae Jung Gim;Rino Choi;Jae Kyeong Jeong;
Appeared in: IEEE Electron Device Letters
Publication date: Nov 2017, volume: 38, issue:11, pages: 1543 - 1546
Publisher: IEEE
 
» Performance of Energy-Harvesting Receivers With Time-Switching Architecture
Abstract:
The analysis and optimization of energy-harvesting transmitters and receivers are different. This paper considers an end-to-end communication with an energy-harvesting receiver. The receiver has a time-switching architecture and can harvest energy from both a dedicated transmitter and other ambient radio-frequency (RF) sources. We first argue that the energy consumed for decoding (per channel use) can be expressed in terms of the gap to channel capacity and utilize this model to optimize two schemes for receiver operation. The two schemes are harvest-then-receive and harvest-when-receive, and they differ primarily in how and when they use the harvested energy for decoding. For transmission over a single block, we compare their performance from various aspects. Then we consider transmission over multiple blocks. When the energy harvested is all from the transmitter, we provide the solution for choosing the optimal code rate and fraction of channels used for energy harvesting for each block. When the energy harvested can also be from other RF sources, we provide a table-search algorithm to find a solution. Finally, we present some numerical examples to validate the accuracy of our analysis.
Autors: Zhengwei Ni;Mehul Motani;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Nov 2017, volume: 16, issue:11, pages: 7252 - 7263
Publisher: IEEE
 
» Performance of Generalized Frequency Division Multiplexing Based Physical Layer in Vehicular Communications
Abstract:
Vehicular communications enable information exchange among vehicles including the roadside infrastructure. This has led to applications to primarily increase road safety and traffic efficiency. Standardization efforts on vehicular communications are underway. The physical layer (PHY) is defined based on the IEEE 802.11 family of WiFi standards operating at the 5.9 GHz frequency band and on extensions of long-term evolution (LTE); in both cases orthogonal frequency division multiplexing (OFDM) is the waveform of choice. Since the typical environment of WiFi deployment is very different to the vehicular communication environment, it is a challenging task to adapt the WiFi-based PHY for providing reliable and real-time communications under highly time- and frequency-selective fading channels. In this paper, the employment of an alternative waveform termed generalized frequency division multiplexing (GFDM) for vehicular communication is investigated. Specifically, a GFDM-based packet design is proposed on the basis of the standard-compliant OFDM-based PHY configuration. On the receiver side, this paper focuses on developing synchronization, channel estimation, and equalization algorithms. The performance of the resulting GFDM-based PHY is verified and compared with the OFDM-based one by means of simulation. The obtained results demonstrate that the proposed GFDM-based PHY can utilize the time and frequency resources more efficiently, and outperform particularly under challenging channel conditions. Additionally, the low out-of-band emission of GFDM is a desirable feature for future multichannel operation (MCO) in vehicular communications.
Autors: Dan Zhang;Andreas Festag;Gerhard P. Fettweis;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Nov 2017, volume: 66, issue:11, pages: 9809 - 9824
Publisher: IEEE
 
» Performance Scaling Law for Multicell Multiuser Massive MIMO
Abstract:
This paper provides a comprehensive scaling law-based performance analysis for multicell multiuser massive multiple-input-multiple-output (MIMO) downlink systems. Imperfect channel state information (CSI), pilot contamination, and channel spatial correlation are all considered. First, a sum-rate lower bound is derived by exploiting the asymptotically deterministic property of the received signal power, while keeping the random nature of other components in the signal-to-interference-plus-noise-ratio (SINR) intact. Via a general scaling model on important network parameters, including the number of users, the channel training energy and the data transmission power, with respect to the number of base station antennas, the asymptotic scaling law of the effective SINR is obtained, which reveals quantitatively the tradeoff of the network parameters. More importantly, pilot contamination and pilot contamination elimination (PCE) are considered in the analytical framework. In addition, the applicability of the derived asymptotic scaling law in practical systems with large but finite antenna numbers are discussed. Finally, sufficient conditions on the parameter scalings for the SINR to be asymptotically deterministic in the sense of mean square convergence are provided, which covers existing results on such analysis as special cases and shows the effect of PCE explicitly.
Autors: Cheng Zhang;Yindi Jing;Yongming Huang;Luxi Yang;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Nov 2017, volume: 66, issue:11, pages: 9890 - 9903
Publisher: IEEE
 
» Performance-Based Linearization Approach for Modeling Induction Motor Drive Loads in Dynamic Simulation
Abstract:
This paper describes a technique to model a vector-controlled induction motor drive in large-scale phasor-level dynamic simulation programs. The performance-based load model is implemented by obtaining the linearized power-voltage and power-frequency transfer functions from test data or from detailed electro-magnetic transient simulation used as a surrogate for test data. Voltage and frequency modulations are performed to obtain the amplitude and phase responses of the detailed vector-controlled drive model for a range of discrete frequencies. The prediction error minimization technique is utilized to generate best-fit analytical transfer function expressions. The electrical interface of the performance-based drive load model is developed to interact with the external system in positive-sequence dynamic simulation programs. The drive model is used to investigate the relative damping effects of drive-connected and direct-connected motors on system voltage and frequency oscillations.
Autors: Yuan Liu;Vijay Vittal;John Undrill;
Appeared in: IEEE Transactions on Power Systems
Publication date: Nov 2017, volume: 32, issue:6, pages: 4636 - 4643
Publisher: IEEE
 
» Performances Analysis of Coherently Integrated CPF for LFM Signal Under Low SNR and Its Application to Ground Moving Target Imaging
Abstract:
The detection and parameters estimation of linear frequency-modulated (LFM) signal are important for modern radar applications, but they are also challenged by the fact that echo signal is often of low signal-to-noise ratio (SNR) due to reasons of long imaging distance and/or limited transmitted power, and the target of small size and/or hidden characteristics. To enhance the SNR, in our previous work, a novel coherently integrated cubic phase function (CICPF) was recently developed for the parameters estimation of the multicomponent LFM signal. In the CICPF, the auto-terms are coherently integrated to enhance the performance in the case of low SNR and also to suppress the cross-terms and spurious peaks. In this paper, as an extension of our previous work, the theoretical performance analyses including several important properties and the fast implementation are provided. Furthermore, the asymptotic mean squared error of a CICPF-based estimator as well as the output SNR of a CICPF-based detector are theoretically derived in closed-forms. From the performance point of view, the proposed CICPF attains the Cramer-Rao bound at low input SNR. The complexity analysis also indicates that the CICPF with the nonuniform fast Fourier transform is computationally efficient without needing the interpolation operation and parameter search. Numerical studies of the CICPF confirm the theoretical analysis and demonstrate superior performance of the proposed approach compared with other state-of-the-art approaches, especially under the low-SNR condition. Finally, the proposed CICPF is applied for the ground moving target imaging in synthetic aperture radar. Results using simulated and experimental data demonstrate that it provides an effective means to obtain well-focused image for ground moving targets.
Autors: Dong Li;Muyang Zhan;Jia Su;Hongqing Liu;Xuepan Zhang;Guisheng Liao;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Nov 2017, volume: 55, issue:11, pages: 6402 - 6419
Publisher: IEEE
 
» Perpendicular Grating Coupler Based on a Blazed Antiback-Reflection Structure
Abstract:
Silicon photonic grating couplers are demonstrated featuring a perfect vertical coupling and predicted coupling efficiencies of 87% and 78% with an apodized and a standard periodic structure, respectively. Vertical coupling is usually difficult to be achieved with standard diffraction gratings, since both the forward and backward scattered light meet the Bragg condition alike. In this work a vertical grating coupler which satisfies both high directionality (> 97%) and low back-reflection (<; 1%) simultaneously is realized using a blazed sub-wavelength structure. The measured maximum coupling efficiencies with a standard single-mfiber are -1.5 dB and -2.2 dB for apodized and periodic structures, respectively. The suggested structure offers an ultimate solution for compact coupling schemes in Si photonics, since it meets the most important needs of grating couplers, which are directionality, ease of fabrication, and a possibility to vertically couple. The vertical grating coupler are fabricated on a silicon-on-insulator wafer with a 220 nm-thick silicon layer, relying only on a 2-step etching technology.
Autors: Tatsuhiko Watanabe;Masafumi Ayata;Ueli Koch;Yuriy Fedoryshyn;Juerg Leuthold;
Appeared in: Journal of Lightwave Technology
Publication date: Nov 2017, volume: 35, issue:21, pages: 4663 - 4669
Publisher: IEEE
 
» Perpendicular-Corporate Feed in Three-Layered Parallel-Plate Radiating-Slot Array
Abstract:
We propose a perpendicular-corporate feed in a three-layered parallel-plate radiating-slot array to remove the x-shaped cavity walls completely in the radiating part of the conventional planar corporate-feed waveguide slot array antenna. Coupling apertures on the bottom excite radiating slots spaced with the half of their spacing on the middle in the parallel plates. We place dielectric with proper permittivity in the region between the coupling aperture and the radiating-slot layer to excite a standing wave strongly there for a large number of slots. A parasitic-slot layer is added on the top to improve the bandwidth. A slot array antenna is designed for uniform excitation with the perpendicular and the planar corporate feeds, and fabricated in the 60 GHz band. At the design frequency of 61.5 GHz, the measured directivity is 33.5 dBi with the aperture efficiency of 90.6%.
Autors: Hisanori Irie;Jiro Hirokawa;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Nov 2017, volume: 65, issue:11, pages: 5829 - 5836
Publisher: IEEE
 
» Personalized Prediction of Vehicle Energy Consumption Based on Participatory Sensing
Abstract:
The advent of abundant on-board sensors and electronic devices in vehicles populates the paradigm of participatory sensing to harness crowd-sourced data gathering for intelligent transportation applications, such as distance-to-empty prediction and eco-routing. While participatory sensing can provide diverse driving data, there lacks a systematic study of effective utilization of the data for personalized prediction. There are considerable challenges on how to interpolate the missing data from a sparse data set, which often arises from participatory sensing. This paper presents and compares various approaches for personalized vehicle energy consumption prediction, including a blackbox framework that identifies driver/vehicle/environment-dependent factors and a collaborative filtering approach based on matrix factorization. Furthermore, a case study of distance-to-empty prediction for electric vehicles by participatory sensing data is conducted and evaluated empirically, which shows that our approaches can significantly improve the prediction accuracy.
Autors: Chien-Ming Tseng;Chi-Kin Chau;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: Nov 2017, volume: 18, issue:11, pages: 3103 - 3113
Publisher: IEEE
 
» Personalized Social Image Recommendation Method Based on User-Image-Tag Model
Abstract:
In the social image sharing websites (such as Flickr), users are allowed to upload images and tag them with tags. Due to the diversities of users' interests, different users may tag the same image with different tags. Therefore, tags not only reveal some important image semantic clues, but also show user's preference, which can provide a new effective solution for overcoming the semantic gap as well as realizing a personalized recommendation. In this paper, a personalized social image recommendation method based on user-image-tag model is proposed. The main contributions of our work are 1) to efficiently make use of tags, social image tags are re-ranked according to the image content; 2) to obtain user preference, a user-image-tag model is constructed with tripartite graph according to the correlation among users, images and top-ranking tags; and 3) a personalized social recommendation system is implemented based on user-image-tag model. Experimental results proved that our method can significantly improve the accuracy of personalized image recommendation.
Autors: Jing Zhang;Ying Yang;Qi Tian;Li Zhuo;Xin Liu;
Appeared in: IEEE Transactions on Multimedia
Publication date: Nov 2017, volume: 19, issue:11, pages: 2439 - 2449
Publisher: IEEE
 
» PF1000 High-Energy Plasma Focus Device Operated With Neon as a Copious Soft X-Ray Source
Abstract:
The measured current waveforms of PF1000 plasma focus operating in neon are first fitted to the computed currents using the Lee model for the pressures of 0.5 and 0.8 torr. The fitting fixes the model parameters. The code is then run to study and to optimize the soft X-ray yield from (~352 kJ) PF1000 device. The maximum characteristic soft X-ray (H-like and He-like lines) yield of 4.2 kJ is found to occur at the pressure of 0.85 torr, with the pinch duration of 207 ns and with an all-line yield of 4.8 kJ. Maximum compression (corresponding to smallest pinch radius) of 0.585 cm with the duration of 224 ns is obtained at 1 torr with the greatest all-line yield of 7.1 kJ but a lower characteristic soft X-ray yield of 3.2 kJ. Detailed computation results indicate that the maximum compression (minimum pinch radius) at 1 torr is attributed to two mechanisms: thermodynamics specific heat ratio effects and radiative losses.
Autors: Mohamad Akel;S. Ismael;S. Lee;S. H. Saw;H. J. Kunze;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Nov 2017, volume: 45, issue:11, pages: 2979 - 2983
Publisher: IEEE
 
» Phase and Hyperfine Structures of Melt-spun Nanocrystalline (Ce1–xNdx)16Fe78B6 Alloys
Abstract:
To reduce the cost of the Nd–Fe–B magnets, the Ce element was suggested to be used as a replacement of Nd element. In this paper, nanocrystalline (Ce1–xNdx)16Fe78B6 (–0.7) alloys were prepared by melt spinning. The X-ray diffraction (XRD) results indicate that the alloys are composed of (NdCe)2Fe14B (2:14:1) phase and (CeNd)Fe2 (1:2) phase for 0 < 0.6, and the 1:2 phase was replaced by (NdCe)Fe4B4 (1:4:4) phase when and 0.7. The hyperfine parameters characteristics of the 2:14:1 phases were estimated from 300 K 57Fe Mössbauer spectra, as well as their contents and those of other intergranular phases. In addition to the 2:14:1, 1:2, and 1:4:4 phases, a small content of the rare earth-rich phase was also detected in all the alloys, which was not able to be observed by the XRD characterization. Based upon the hyperfine field, the average magnetic moment of Fe in 2:14:1 phase could be determined as 1.56, 1.62, 1.67, 1.73, 1.78, 1.83, 1.85, and for , 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, and 0.7, respectively. The minor change between the ( and is discussed. Both the present local and macroscopic magnetic parameters significantly contribute to understand the fundamental role of Ce in those nanocrystalline Nd–Ce–Fe–B permanent magnets.
Autors: L. Z. Zhao;H. Y. Yu;W. T. Guo;J. S. Zhang;Z. Y. Zhang;M. Hussain;Z. W. Liu;J. M. Greneche;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Phase Compensation Scheme for Fiber-Optic Interferometric Vibration Demodulation
Abstract:
In order to expand the dynamic range of fiber-optic interferometric demodulation, a novel phase compensation scheme based on the phase generated carrier arctangent algorithm (PGC-arctan) is proposed, which overcomes the limitation of the amplitude range from to for arbitrary signals; and a Michelson interferometer measurement system is established to verify the rationality of the compensation algorithm. The phase compensation algorithm is based on analysis of the instantaneous function of the arctangent signal during the phase hopping process, while overcoming the problem of phase winding. Experimental results confirmed the feasibility of the phase compensation scheme as predicted by theoretical and simulation analysis. In particular, the new scheme was shown to be effective in responding to arbitrary large-amplitude and time-dependent vibrational input, with the additional benefit of a strong ability to suppress system and ambient noise.
Autors: Tianying Chang;Jinpeng Lang;Wei Sun;Jiandong Chen;Miao Yu;Wenzhi Gao;Hong-Liang Cui;
Appeared in: IEEE Sensors Journal
Publication date: Nov 2017, volume: 17, issue:22, pages: 7448 - 7454
Publisher: IEEE
 
» Phase Stabilities and Magnetic Properties of Mn-Deficient and Ge-Substituted Mn3Ga With D022 Structure
Abstract:
We have investigated phase stabilities and magnetic properties of the tetragonal D022 phase in Mn-deficient Mn3–xGa and Ge-substituted Mn3Ga1–yGey. A transition from the D022 to L10 phase is observed in the composition range of –0.8 in Mn3–xGa. On the other hand, the D022 phase is confirmed in the overall composition of Mn3Ga1–yGey. The thermal stability of the D022 phase strongly depends on the Ge content compared with the Mn deficiency. Magnetization of Mn3–xGa is increased by introducing the Mn deficiency, whereas that of Mn3Ga1–yGey decreases with increasing Ge content despite a constant number of Mn atoms. This result suggests that the magnitude of magnetic moment of Mn atom in Mn3Ga1–yGey is influenced by variations of valence electron and structural properties caused by the Ge substitution.
Autors: Hironari Okada;Toru Sasaki;Yudai Syoji;Rie Y. Umetsu;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 6
Publisher: IEEE
 
» Phase-Change Memory—Towards a Storage-Class Memory
Abstract:
Phase-change memory (PCM) has undergone significant academic and industrial research in the last 15 years. After much development, it is now poised to enter the market as a storage-class memory (SCM), with performance and cost between that of NAND flash and DRAM. In this paper, we review the history of phase-transforming chalcogenides leading up to our current understanding of PCM as either a storage-type SCM, with high-density and better than NAND flash endurance, write speeds, and retention, or a memory-type SCM, with fast read/write times to function as a nonvolatile DRAM. Several of the key findings from the community relating to device dimensional scaling, cell design, thermal engineering, material exploration, and storing multiple levels per cell will be discussed. These areas have dramatically impacted the course of development and understanding of PCM. We will highlight the performance gains attained and the future prospects, which will help drive PCM to be as ubiquitous as NAND flash in the upcoming decade.
Autors: Scott W. Fong;Christopher M. Neumann;H.-S. Philip Wong;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Nov 2017, volume: 64, issue:11, pages: 4374 - 4385
Publisher: IEEE
 
» Photoconductance Decay Characterization of 3D Multi-Fin Silicon on SOI Substrates
Abstract:
This letter is concerned with the electrical characterization of 3D fin-shaped silicon used as a channel in novel transistor architectures. This approach adapts photoconductance decay minority carrier measurement methodology to the needs of electrical characterization of fin-shaped semiconductor materials systems. The results obtained indicate as high as threefold decrease in the minority carrier lifetime in the fin-shaped Si as compared with the same active planar Si prior to fins definition (from to ). A cause of this decrease is significant expansion of the effective surface area of the finned samples and the resulting increase in recombination sites related to the structurally disordered sidewalls of the fins formed via etching. Hydrogen termination of the finned surfaces did not provide long-term passivation of the surfaces, which was accomplished only by atomic layer deposition of 3-nm-thick layer of Al2O3.
Autors: P. J. Drummond;A. Wali;M. J. Barth;A. M. Diehm;S. Datta;J. Ruzyllo;
Appeared in: IEEE Electron Device Letters
Publication date: Nov 2017, volume: 38, issue:11, pages: 1513 - 1515
Publisher: IEEE
 
» Physical-Based Analytical Model of Amorphous InGaZnO TFTs Including Deep, Tail, and Free States
Abstract:
Amorphous InGaZnO (a-IGZO) is a candidate material for thin-film transistors (TFTs) owing to its large electron mobility and good uniformity over large area. a-IGZO TFTs drain current models are essential for further pushing both a-IGZO TFTs technology and circuit design. In this paper, we propose a simple physical-based and analytical model of the drain current of a-IGZO TFTs. The model is valid in both non degenerate and degenerate conduction and it accounts for deep interface states, tail localized states, and free delocalized band states. The model is validated with the measurements of both coplanar and staggered a-IGZO TFTs. It provides key physical and material parameters of the transistor and, owing to its class formulation, it can be straightforwardly implemented in circuit simulators.
Autors: Matteo Ghittorelli;Zsolt Miklós Kovács-Vajna;Fabrizio Torricelli;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Nov 2017, volume: 64, issue:11, pages: 4510 - 4517
Publisher: IEEE
 
» Physical-Layer Security in MCF-Based SDM-EONs: Would Crosstalk-Aware Service Provisioning be Good Enough?
Abstract:
In this paper, we consider a multicore fiber (MCF)-enabled elastic optical network, in which certain nodes have a lower trust level than the others, and study how to provision lightpaths with considerations of the impairments and security vulnerabilities caused by intercore crosstalk. We propose attack-aware routing, spectrum, and core assignment algorithms that give priority to avoiding physical-layer security threats and then try to reduce the crosstalk-induced impairments. Specifically, both static network planning and dynamic network provisioning are investigated. For static planning, we first formulate an integer linear programming (ILP) model to optimize the spectrum utilization and intercore crosstalk level jointly and then propose a time-efficient heuristic. Simulation results confirm that the proposed heuristic can approximate the ILP's performance with much higher time efficiency in a small-scale network and outperform an existing benchmark in large networks. For dynamic provisioning, we design a heuristic to balance the tradeoff between blocking probability and crosstalk and conduct extensive simulations to verify its effectiveness.
Autors: Jing Zhu;Zuqing Zhu;
Appeared in: Journal of Lightwave Technology
Publication date: Nov 2017, volume: 35, issue:22, pages: 4826 - 4837
Publisher: IEEE
 
» PIC: Enable Large-Scale Privacy Preserving Content-Based Image Search on Cloud
Abstract:
Many cloud platforms emerge to meet urgent requirements for large-volume personal image store, sharing and search. Though most would agree that images contain rich sensitive information (e.g., people, location and event) and people’s privacy concerns hinder their participation into untrusted services, today’s cloud platforms provide little support for image privacy protection. Facing large-scale images from multiple users, it is extremely challenging for the cloud to maintain the index structure and schedule parallel computation without learning anything about the image content and indices. In this work, we introduce a novel system PIC: A Privacy-preserving Image search system on Cloud, which is a step towards feasible cloud services which provide secure content-based large-scale image search with fine-grained access control. Users can search on others’ images if they are authorized by the image owners. Majority of the computationally intensive jobs are handled by the cloud, and a querier can now simply send the query and receive the result. Specially, to deal with massive images, we design our system suitable for distributed and parallel computation and introduce several optimizations to further expedite the search process. Our security analysis and prototype system evaluation results show that PIC successfully protects the image privacy at a low cost of computation and communication.
Autors: Lan Zhang;Taeho Jung;Kebin Liu;Xiang-Yang Li;Xuan Ding;Jiaxi Gu;Yunhao Liu;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Nov 2017, volume: 28, issue:11, pages: 3258 - 3271
Publisher: IEEE
 
» Pickup Coil Counter for Detecting the Presence of Trains Operated by Wireless Power Transfer
Abstract:
An axle counter is a popularly used device for detecting passing trains. They detect train wheels by the change of the magnetic field, made by the train wheels, in a receiving coil. Wireless power transfer (WPT) systems are used to deliver tractive power to electric trains by magnetic resonance. They consist of a pickup coil onboard the train, a supply coil on the track, and related trackside electronic circuits. When a WPT system is proximate to an axle counter, the magnetic field of the WPT can produce significant electromagnetic interference, significantly affecting the performance of the axle counter. Since the WPT system is an emerging power supply system for future railways, an alternative device for detecting trains is considered necessary. A novel device called the pickup coil counter (PCC) is proposed for this purpose. Unlike the axle counter, which detects the train’s wheels, the PCC detects the WPT pickup coil onboard the train using a sensor coil wound around the WPT supply coil on the track and a detection circuit in trackside equipment. The operating concept of the PCC is explained. Its detection performance was evaluated by 3-D FEM simulation and experiment, and the results are presented.
Autors: Karam Hwang;Dongwook Kim;Dongsoo Har;Seungyoung Ahn;
Appeared in: IEEE Sensors Journal
Publication date: Nov 2017, volume: 17, issue:22, pages: 7526 - 7532
Publisher: IEEE
 
» Piezomagnetic Performance of Stress-Annealed FeAlB Alloys
Abstract:
Two FeAlB polycrystalline alloys were stress annealed and had the piezomagnetic behavior determined before and after the stress annealing (SA). The concentration of boron is constant, 1.6% (at%). The alloys are basically formed by the phase Fe2B dispersed in a bcc matrix. The bcc matrix can be formed of a disordered and/or ordered structure, depending on ratio of Fe:Al, that was fixed as 86Fe:14Al and 80Fe:20Al. Magnetostriction and magnetic induction were measured as a function of magnetic field and compressive stresses. The piezomagnetic coefficient improvement due to SA was achieved, in which is the magnetostriction and H the applied magnetic field. SA causes the reorientation of the magnetic moment of the material creating an artificial magnetic anisotropy. The behavior of the coefficient d33 varies due to changes in Al content, since the magnetocrystalline anisotropy of the alloy depends on the ordering of the bcc matrix. Values of d33 up to 4 nm/A were reached for the polycrystalline alloy with 14% Al (at%) in an interval of compressive stresses of MPa. This large interval of compression stress is due to the presence of the Fe2B phase.
Autors: Cristina Bormio-Nunes;Mateus Botani de Souza Dias;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Plasma Exposure Behavior of Yttrium Oxide Film Formed by Aerosol Deposition Method
Abstract:
Aerosol deposition (AD) method is technique for forming high density ceramic films on substrate material surface at room temperature. The yttrium oxide films formed by the AD method (AD-Y2O3 films) have been developed as plasma resistance coating used for the plasma etching equipment. In recent years, plasma eroded particles from chamber components of the etching devices are regarded as a serious issue that they reduce the semiconductor device yield rate. AD-Y2O3 films which have excellent plasma resistance can reduce the eroded particles in the plasma etching equipment and greatly have contributed to manufacturing high integrated semiconductor devices. In this paper, the plasma erosion behavior of AD-Y2O3 films were investigated compared with sintered Al2O3, sintered Y2O3 and thermal splayed Y2O3 in order to clarify the reason why AD Y2O3 films were superior as plasma resistance material. The plasma etching rates of AD-Y2O3 films were not significantly different from other samples. It was assumed that the etching rates were dependent on the chemical stability to fluorine plasma of material. On the other hand, the surface roughness difference before and after plasma exposure of AD-Y2O3 films were much smaller than other samples. It was assumed that the surface roughness difference is dependent on the crystalline size of material. The structure of AD-Y2O3 films, which had high density and nano-crystalline structure, were eroded homogeneously and smoothly. It suggests AD-Y2O3 films do not generate large eroded particles and are superior to reduce the eroded particles in the etching devices.
Autors: Hiroaki Ashizawa;Masakatsu Kiyohara;
Appeared in: IEEE Transactions on Semiconductor Manufacturing
Publication date: Nov 2017, volume: 30, issue:4, pages: 357 - 361
Publisher: IEEE
 
» Plasma Response to Resonant Magnetic Perturbations in Large Aspect Ratio Tokamaks
Abstract:
In this paper, a plasma response model is investigated for large aspect ratio tokamaks, on the presence of external nonaxisymmetric resonant magnetic perturbations. To control plasma confinement, the plasma is perturbed by external resonant helical windings, similar to those introduced by an ergodic magnetic limiter. The plasma response to the perturbation is modeled as an additional magnetic perturbation, created by a current sheet on the main perturbed resonant surface, vanishing the radial component of the total magnetic field in the considered resonant surface. In order to show the influence of the plasma response on the field line topology, the field line differential equations are integrated numerically, showing the reduction of magnetic island sizes and the regularization of chaotic regions around the resonant surface where the response was introduced, in agreement with results observed in sophisticated simulation codes. Finally, the connection lengths indicate that, regarding their distribution, the plasma response introduces a homogenization effect which may affect the deposition patterns at the tokamak wall.
Autors: André Carlos Fraile;Marisa Roberto;Iberê Luiz Caldas;Caroline Gameiro Lopes Martins;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Nov 2017, volume: 45, issue:11, pages: 2906 - 2912
Publisher: IEEE
 
» PlatEMO: A MATLAB Platform for Evolutionary Multi-Objective Optimization [Educational Forum]
Abstract:
Over the last three decades, a large number of evolutionary algorithms have been developed for solving multi-objective optimization problems. However, there lacks an upto-date and comprehensive software platform for researchers to properly benchmark existing algorithms and for practitioners to apply selected algorithms to solve their real-world problems. The demand of such a common tool becomes even more urgent, when the source code of many proposed algorithms has not been made publicly available. To address these issues, we have developed a MATLAB platform for evolutionary multi-objective optimization in this paper, called PlatEMO, which includes more than 50 multiobjective evolutionary algorithms and more than 100 multi-objective test problems, along with several widely used performance indicators. With a user-friendly graphical user interface, PlatEMO enables users to easily compare several evolutionary algorithms at one time and collect statistical results in Excel or LaTeX files. More importantly, PlatEMO is completely open source, such that users are able to develop new algorithms on the basis of it. This paper introduces the main features of PlatEMO and illustrates how to use it for performing comparative experiments, embedding new algorithms, creating new test problems, and developing performance indicators. Source code of PlatEMO is now available at: http://bimk.ahu.edu.cn/index.php?s=/Index/Software/index.html.
Autors: Ye Tian;Ran Cheng;Xingyi Zhang;Yaochu Jin;
Appeared in: IEEE Computational Intelligence Magazine
Publication date: Nov 2017, volume: 12, issue:4, pages: 73 - 87
Publisher: IEEE
 
» Polar Channel Coding Schemes for Two-Dimensional Magnetic Recording Systems
Abstract:
This paper proposes new two-dimensional magnetic recording (TDMR) systems using polar channel coding as practical error correction coding. It is known that the time and space complexities of the encoding/decoding algorithms based on polar channel coding are , where is the codeword (block) length. If we compare the error-correction performance of a polar code with that of a low-density parity-check (LDPC) code in the same rate, it is known that the polar code has a longer length and its decoder still has a lower implementation complexity than the LDPC decoder. Therefore, relatively low-complexity coding schemes are preferable for any TDMR systems under high rates and relatively long codeword lengths. In this paper, the proposed TDMR system serially concatenates a two-dimensional (2-D) modulation code with one-dimensional (1-D) polar codes in each down-track direction. These element polar codes are designed on the fundamentals of the channel polarization theory, which are applied for channels with memory. Actually, it evaluates the performance of the signal processing scheme with concatenated coding and generalized partial response equalization for the proposed TDMR system using bit-patterned media by computer simulations. As a result, it shows that the block error rate performance of the proposed TDMR system with the 2-D modulation and polar channel coding schemes is superior to that of the 1-D system with the conventional 1-D high rate modulation and LDPC coding schemes.
Autors: Hidetoshi Saito;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 7
Publisher: IEEE
 
» Polar Opinion Dynamics in Social Networks
Abstract:
For decades, scientists have studied opinion formation in social networks, where information travels via word of mouth. The particularly interesting case is when polar opinions—Democrats versus Republicans or iOS versus Android—compete in the network. The central problem is to design and analyze a model that captures how polar opinions evolve in the real world. In this paper, we propose a general nonlinear model of polar opinion dynamics, rooted in several theories of sociology and social psychology. The model's key distinguishing trait is that unlike in the existing linear models, such as DeGroot and Friedkin–Johnsen models, an individual's susceptibility to persuasion is a function of his or her current opinion. For example, a person holding a neutral opinion may be rather malleable, while “extremists” may be strongly committed to their current beliefs. We also study three specializations of our general model, whose susceptibility functions correspond to different sociopsychological theories. We provide a comprehensive theoretical analysis of our nonlinear models’ behavior using several tools from nonsmooth analysis of dynamical systems. To study convergence, we use nonsmooth max–min Lyapunov functions together with the generalized Invariance Principle. For our general model, we derive a general sufficient condition for the convergence to consensus. For the specialized models, we provide a full theoretical analysis of their convergence—whether to consensus or disagreement. Our results are rather general and easily apply to the analysis of other nonlinear models defined over directed networks, with Lyapunov functions constructed out of convex components.
Autors: Victor Amelkin;Francesco Bullo;Ambuj K. Singh;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Nov 2017, volume: 62, issue:11, pages: 5650 - 5665
Publisher: IEEE
 
» Polarimetric SAR Image Classification Using a Wishart Test Statistic and a Wishart Dissimilarity Measure
Abstract:
Land-cover classification in polarimetric synthetic aperture radar images is a vital technique that has been developed for years. The Wishart distribution, which the polarimetric coherence matrix obeys, has been researched to design the well-known Wishart classifier. This model is appropriate for homogeneous scenes, but it usually fails in reality when a category consists of several subcategories or clusters. Therefore, a simple but powerful sample-merging strategy is proposed to generate representative subcenters, based on a dissimilarity measure. In addition, a weighted likelihood-ratio criterion is also proposed to further improve the performance of the Wishart distribution-based classification, based on the Wishart test statistic. Two experiments on EMISAR and UAVSAR data sets confirm that combining the proposed strategies can achieve better results than can the Wishart classifier and the other existing methods.
Autors: Weidong Sun;Pingxiang Li;Jie Yang;Lingli Zhao;Minyi Li;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Nov 2017, volume: 14, issue:11, pages: 2022 - 2026
Publisher: IEEE
 
» Polarity Control of GaN and Realization of GaN Schottky Barrier Diode Based on Lateral Polarity Structure
Abstract:
This paper reports investigation on a polarity control scheme of GaN thin films and realization of Schottky barrier diode (SBD) fabricated on a lateral-polarity-structure (LPS) GaN without intentionally doping. Specifically, Ga-polar and N-polar GaN were grown simultaneously side by side on sapphire substrate with patterned AlN buffer. Due to the surface energy difference between two polarities, N-polar regions are n-type conductive with rough surface morphology, while Ga-polar regions are semi-insulating with atomic flat surface morphology. Annealing conditions of both ohmic contact and Schottky contact were investigated. Current–voltage (I–V) characteristic revealed that the SBD fabricated on LPS GaN has higher forward current, barrier height closer to 0.7 eV, and ideality factor closer to unity compared to SBD fabricated on conventional undoped GaN. The specific on-state resistance ( for the SBD based on LPS GaN is 77 lower than the SBD fabricated on conventional GaN. With oxide passivation on SBD surface, forward current exceeds 0.2 A at 10 V, while reverse current is less than 10−5 A at −10 V, respectively. The utilization of LPS in SBD demonstrates a promising approach for the development of lateral n+/n SBD with a simple fabrication scheme.
Autors: Moheb Sheikhi;Junmei Li;Fanping Meng;Hongwei Li;Shiping Guo;Lingyan Liang;Hongtao Cao;Pingqi Gao;Jichun Ye;Wei Guo;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Nov 2017, volume: 64, issue:11, pages: 4424 - 4429
Publisher: IEEE
 
» Polarization of the Rényi Information Dimension With Applications to Compressed Sensing
Abstract:
In this paper, we show that the Hadamard matrix acts as an extractor over the reals of the Rényi Information Dimension (RID), in an analogous way to how it acts as an extractor of the discrete entropy over finite fields. More precisely, we prove that the RID of an i.i.d. sequence of mixture random variables polarizes to the extremal values of 0 and 1 (corresponding to discrete and continuous distributions) when transformed by a Hadamard matrix. Furthermore, we prove that the polarization pattern of the RID admits a closed form expression and follows exactly the Binary Erasure Channel (BEC) polarization pattern in the discrete setting. We discuss the applications of the RID polarization to Compressed Sensing of i.i.d. sources. In particular, we use the RID polarization to construct a family of deterministic ±1-valued sensing matrices for Compressed Sensing. We run numerical simulations to compare the performance of the resulting matrices with that of the random Gaussian and the random Hadamard matrices. The results indicate that the proposed matrices afford competitive performances, while being explicitly constructed.
Autors: Saeid Haghighatshoar;Emmanuel Abbe;
Appeared in: IEEE Transactions on Information Theory
Publication date: Nov 2017, volume: 63, issue:11, pages: 6858 - 6868
Publisher: IEEE
 
» Polarization Shift Keying (PolarSK): System Scheme and Performance Analysis
Abstract:
The single-radio-frequency (RF) multiple-input-multiple-output (MIMO) system has been proposed to pursue a high spectral efficiency while keeping a low hardware cost and complexity. Recently, the available degrees of freedom (DoF) in the polarization domain has been exploited to reduce the size of the transmit antenna array and provide 1 bit per channel use (bpcu) multiplexing gain for the single-RF MIMO system. Nevertheless, the polarization domain resource still has the potential to provide a higher multiplexing gain in the polarized single-RF MIMO system. In this paper, we propose a generalized polarization shift keying (PolarSK) modulation scheme that uses polarization states in the dual-polarized transmit antenna as an information-bearing unit to increase the overall spectral efficiency. At the receiver, the optimum maximum likelihood (ML) detector is employed to investigate the ultimate performance limit of the PolarSK. A closed-form union upper bound on the average bit error probability (ABEP) of the PolarSK with the optimum ML receiver is derived. Inspired by the analytic ABEP, a constellation diagram optimization algorithm is proposed. To reduce the computational complexity of the receiver, a linear successive interference cancellation (SIC) detection algorithm and a sphere-decoding (SD) detection algorithm are introduced. Through numerical results, performances of the proposed PolarSK in terms of ABEP and computational complexity are analyzed. Furthermore, the PolarSK is analyzed over measured indoor channels. Numerical and measurement results show that the PolarSK scheme outperforms the state-of-the-art dual-polarized/unipolarized SM schemes.
Autors: Jiliang Zhang;Yang Wang;Jie Zhang;Liqin Ding;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Nov 2017, volume: 66, issue:11, pages: 10139 - 10155
Publisher: IEEE
 
» Polarization-Adjustable Planar Array Antenna With SIW-Fed High-Order-Mode Microstrip Patch
Abstract:
This communication presents a high-order-mode microstrip patch antenna driven by substrate integrated waveguide (SIW) for millimeter-wave polarization-adjustable applications. Different polarization status can be yielded from variable excited signals, including vertical and horizontal linear, right-handed and left-handed circular polarizations. In the patch antenna configuration, an enlarged aperture coming from high-order mode makes it easy to be fed by orthogonal SIWs for dual polarizations. Loaded slots on the patch significantly improve the radiation patterns. The impedance bandwidth with dual resonances is originated from the SIW slot and patch modes. A Ka-band antenna array integrated with single-layer SIW feeding network is designed and tested to illustrate this technique. The results manifest that the planar integrated antenna array features adjustable polarization with considerable gain. Furthermore, a two-layer scheme of orthogonal SIW feeding is developed, which would provide a more flexible topology for the scale-expandable array antenna with adjustable polarizations.
Autors: Fengchao Ren;Wei Hong;Ke Wu;Dan Yu;Yangtao Wan;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Nov 2017, volume: 65, issue:11, pages: 6167 - 6172
Publisher: IEEE
 

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