Electrical and Electronics Engineering publications abstract of: 11-2017 sorted by title, page: 5

» Compact High-Isolation LTCC Diplexer Using Common Stub-Loaded Resonator With Controllable Frequencies and Bandwidths
Abstract:
In this paper, a low-temperature co-fired ceramic (LTCC) diplexer is presented with compact size and high isolation. By using the common stub-loaded resonator shared by two channel filters, combining and matching networks are eliminated and only three resonators are used to design the two second-order channel filters, resulting in simple structure and miniaturized size. A novel transmission path is utilized to not only realize the higher channel filter but also prevent the signal at the lower frequency band. And a specific coupling region is selected to simultaneously realize the coupling strength required by lower channel filter and a transmission zero at higher-band frequency. In this way, each channel filter can generate a transmission zero at the passband frequency of the other channel filter, resulting in high isolation. Moreover, the bandwidths and center frequencies of the two channel filters can be individually controlled due to the design flexibility of the multilayer LTCC structure. For demonstration, a diplexer operating at 3.5 and 5.5 GHz is fabricated. The core circuit has the compact size of 1.9 mm mm mm or . Within the 3-dB passbands of the lower and higher channel filters, the measured isolation levels are better than 40 and 45 dB, respectively.
Autors: Jin-Xu Xu;Xiu Yin Zhang;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Nov 2017, volume: 65, issue:11, pages: 4636 - 4644
Publisher: IEEE
 
» Comparative Analysis and Optimization of Dynamic Charging Coils for Roadway-Powered Electric Vehicles
Abstract:
Roadway-powering systems can effectively improve the driving distance of electric vehicles (EVs) while releasing the overdependence on batteries. As the key technical issue, the design of primary and pickup coils determines the dynamic charging performance. In recent years, the double-D-quadrature (DDQ) pickup coil has been increasingly utilized in EV dynamic charging systems by means of the persistence and stability of move-and-charge. However, the impact of primary coils with various topologies on DDQ pickup coils has been nearly unexplored in previous studies. Accordingly, this paper presents a comparative analysis of the circular-shaped, rectangle-shaped and multi-thread primary coils for DDQ-based roadway-powering systems with an emphasis on the transmission power, energization persistence, thermal analysis, and initial investment that aims to provide technical references for further research and development of EV dynamic wireless charging systems.
Autors: Zhen Zhang;Hongliang Pang;Christopher H. T. Lee;Xiangkui Xu;Xile Wei;Jiang Wang;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 6
Publisher: IEEE
 
» Comparative Analysis of Temporal Decorrelation at P-Band and Low L-Band Frequencies Using a Tower-Based Scatterometer Over a Tropical Forest
Abstract:
Temporal decorrelation is a critical parameter for repeat-pass coherent radar processing, including many advanced techniques such as polarimetric SAR interferometry (PolInSAR) and SAR tomography (TomoSAR). Given the multifactorial and unpredictable causes of temporal decorrelation, statistical analysis of long time series of measurements from tower-based scatterometers is the most appropriate method for characterizing how rapidly a specific scene decorrelates. Based on the TropiScat experiment that occurred in a tropical dense forest in French Guiana, this letter proposes a comparative analysis between temporal decorrelation at P-band and at higher frequencies in the range of 800–1000 MHz (the low end of the L-band). This letter aims to support the design of future repeat-pass spaceborne missions and to offer a better understanding of the physics behind temporal decorrelation. Beyond the expected lower values that are found and quantified at the low L-band compared with the P-band, similar decorrelation patterns related to rainy and dry periods are emphasized in addition to the critical impacts of acquisition time during the day.
Autors: A. Hamadi;L. Villard;P. Borderies;C. Albinet;T. Koleck;T. Le Toan;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Nov 2017, volume: 14, issue:11, pages: 1918 - 1922
Publisher: IEEE
 
» Comparative Study of E-Core and C-Core Modular PM Linear Machines With Different Slot/Pole Combinations
Abstract:
Four modular permanent magnet linear machines (PMLMs) with E-core and C-core primary segments and 12-slot/13-pole (12s/13p) and 12-slot/14-pole (12s/14p) slot/pole combinations are compared in this paper. The influences of flux gap width on the electromagnetic performances and power losses have been investigated based on 2-D finite-element modeling. It has been found that, by choosing proper flux gap width, not only the average thrust force can be improved but also the force ripple and iron losses can be reduced for all the machines. Also, the E-core modular PMLM has higher thrust force and lower detent force compared with the C-core modular PMLM with respect to the same slot/pole combination. Moreover, the 12s/13p modular PMLMs can achieve better electromagnetic performances than the 12s/14p ones regardless of E-core or C-core primary structures. Finally, by shaping the end teeth, the detent force and force ripple of the four modular PMLMs are further mitigated. The 12s/13p E-core modular PMLM is proven to be the best type among these four modular machines.
Autors: Yihua Yao;Qinfen Lu;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 7
Publisher: IEEE
 
» Comparative Study of Microfabricated Inductors/Transformers for High-Frequency Power Applications
Abstract:
This paper presents a comparative study on different microfabricated inductors (microtransformers), which are suitable for high-frequency power application. The main topic of this study is comparing and analyzing the effect of some factors such as material type, number of turns, and coil form on microinductor performance considering a fixed chip size, fixed magnetic core size, and core form. Two different microtransformer designs with different magnetic core materials are considered in this work. The core materials used in this work are NiFe45/55 and CoFe45/55. Also, two types of device packages are developed, namely, Quad Flat No-Lead and FR4 embedded packages. For device testing, different high-frequency switching regulators available on the market are used. This study shows the influence of different parameters on the performance of a certain high-frequency application. In this paper, we discuss the influence of the design, magnetic material, and package type on thermal performance and the efficiency of the power application.
Autors: Dragan Dinulovic;Mahmoud Shousha;Martin Haug;Sebastian Beringer;Marc C. Wurz;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 7
Publisher: IEEE
 
» Comparative Study of PM-Assisted SynRM and IPMSM on Constant Power Speed Range for EV Applications
Abstract:
This paper analyzes and compares the performances of permanent-magnet-assisted synchronous reluctance machines (PMa-SynRMs) and interior permanent magnet synchronous machine (IPMSM) on their constant power speed range (CPSR) capability for electric vehicle (EV) applications. The recent trend of less rare-earth magnet makes the IPMSM unfavorable despite its excellent CPSR. As an alternative, the PMa-SynRM possesses a higher saliency with lower PM quantity. The two different rotor designs would affect the CPSR and these need to be investigated and compared. As a key performance index for EV traction motors, the CPSR calculated by analytical methods often suffers low accuracy due to omission of saturation. Finite-element analysis (FEA) can be used to obtain the CPSR but significant computation time is required. This would be disadvantageous for accurate performance prediction in design stage. To resolve these problems, six 10 kW, 30 Nm/L designs are studied and compared, covering IPMSMs and PMa-SynRMs. An approach associating analytical methods with FEA is developed for accurate and rapid calculation of CPSR for these machines. A discussion on PMa-SynRM rotor designs and suggestion for their PM quantity are provided considering performance, cost, and demagnetization. Two prototypes were tested, one being IPMSM and the other PMa-SynRM to validate the analysis.
Autors: Thanh Anh Huynh;Min-Fu Hsieh;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 6
Publisher: IEEE
 
» Comparison Between the Salient-Pole Synchronous Machine and the Doubly Fed Induction Machine With Regard to Electromagnetic Parasitic Forces and Stator Vibrations
Abstract:
Pumped-storage hydro power plants have been mainly equipped with fixed-speed salient-pole synchronous machines (SPSM). However, the upgrade from fixed-speed technology to variable-speed technology, using doubly fed induction machines (DFIM) brings many benefits in terms of stability and efficiency. This article deals with a DFIM obtained by replacing the rotor of an existing SPSM. The original SPSM had a fractional-slot winding. Although this winding configuration was not causing any problem in the SPSM, it leads to vibration issues in the case of the DFIM. It is shown how this special winding is responsible for electromagnetic forces leading to vibrations and why these vibrations were unnoticed in the case of the SPSM. The influence of the operation point (speed, power factor) on the force magnitude and resulting vibrations is studied. Using a simple and efficient algorithm, it is shown how the winding can be reconnected in order to lower the exciting force.
Autors: Thomas Lugand;Alexander Schwery;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Nov 2017, volume: 53, issue:6, pages: 5284 - 5294
Publisher: IEEE
 
» Comparison of Axial Flux Permanent Magnet Synchronous Machines With Electrical Steel Core and Soft Magnetic Composite Core
Abstract:
This paper presents a comparison of axial flux permanent magnet machines (AFPMs) with an electrical steel core and that with a soft magnetic composite (SMC) core. SMCs have several advantages such as low core loss and low eddy current loss. However, compared with electrical steel, SMCs have poor magnetic properties such as low flux density saturation and unsaturated relative permeability. The analysis of the electromagnetic characteristics in a wide frequency range revealed that for an AFPM using an electric steel core, the performance was excellent in a low-frequency range; however, for an AFPM using an SMC core, the performance improves with an increase in frequency. Finally, the operation area of an AFPM using an SMC core is proposed.
Autors: Chang-Woo Kim;Gang-Hyeon Jang;Jeong-Man Kim;Ji-Hun Ahn;Chan-Ho Baek;Jang-Young Choi;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Comparison of Limiting Loop Model and Elemental Operator Model for Magnetic Hysteresis of Ferromagnetic Materials
Abstract:
This paper introduces a comparative study of two different hysteresis models, limiting loop model and elemental operator model. The former is regarded as a mathematical approach based on the traditional Preisach model. To circumvent the difficulty of determining the distribution function in the Preisach model, the data of the limiting hysteresis loop and a function transform on the Preisach diagram are employed. The latter is a physical method which adopts a vectorial elemental operator with biaxial anisotropy based on the magnetization mechanisms of the ferromagnetic material. These two models are analyzed and compared in terms of the underlying principle, numerical implementation, and calculation accuracy in this paper. To verify the introduced models, the magnetic properties of non-oriented silicon steel Lycore-140 and soft magnetic composite material Somaloy 500 under alternating excitations are measured and compared with simulated results, which show the validity and practicability of the models but with different calculation accuracy and speed.
Autors: Nana Duan;Weijie Xu;Yongjian Li;Shuhong Wang;Youguang Guo;Jianguo Zhu;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Comparison of the Characteristics of Cost-Oriented Designed High-Speed Low-Power Interior PMSM
Abstract:
In this paper, the characteristics of interior permanent magnet synchronous machine (IPMSM) with concentrated windings are evaluated for three different rotor geometries. The reference machine is a fractional horsepower IPMSM with single-layer magnets (1-layered IPMSM). The maximum output power of the machine is 820 W. Based on the electrical properties and machine cost of the reference machine, IPMSM with two different rotor geometries are designed. The first one is an IPMSM with v-shaped magnets and the second one is an IPMSM with double-layer magnets topology (2-layered IPMSM). The machines are compared in two operating points: one in the base speed area and one in the field weakening range. The focus of the machine comparison is the parasitic effects due to the nonsinusoidal rotor field, e.g., back-EMF harmonics, torque harmonics, radial force densities, and iron losses.
Autors: Aryanti Kusuma Putri;Marco Hombitzer;David Franck;Kay Hameyer;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Nov 2017, volume: 53, issue:6, pages: 5262 - 5271
Publisher: IEEE
 
» Comparison of the Linear and Spanwise-Segmented DBD Plasma Actuators on Flow Control Around a NACA0015 Airfoil
Abstract:
In this paper, linear and spanwise-segmented plasma actuator implementations as well as base airfoil with no plasma cases are presented. These approaches are used to control the flow around a NACA0015 airfoil. The experiments were conducted in a wind tunnel at Reynolds number of . The plasma actuators mounted on the leading edge of the airfoil at chord position of 0.1 (). The electrical parameters used for the plasma generating device are set to constant values of 6-kVpp applied voltage and 3.5-kHz excitation frequency. It is observed that the use of spanwise-segmented plasma actuators converts the 2-D flow structure around the airfoil into 3-D forcing flow structure. The change of the wake region width of the airfoil is visualized by using the smoke-wire method. The flow visualization is performed at attack angles of 0°, 5°, 10°, and 15°. In addition, necessary measurements are also made to determine drag and lift forces. A comparative study on the drag and lift forces for the NACA0015 airfoil is performed. As a part of the conclusions, linear and spanwise-segmented plasma actuator implementations as well as base airfoil with no plasma cases are compared and related results on flow control are presented.
Autors: Hürrem Akbıyık;Hakan Yavuz;Yahya Erkan Akansu;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Nov 2017, volume: 45, issue:11, pages: 2913 - 2921
Publisher: IEEE
 
» Comparison on the Coercivity Enhancement of Hot-Deformed Nd2Fe14B-Type Magnets by Doping R70Cu30 (R = Nd, Dy, and Tb) Alloy Powders
Abstract:
Coercivity enhancement effect of the anisotropic hot-deformed NdFeB magnets made from NdFeB MQU-F powders doped with 2 wt% low-melting R70Cu30 (R = Nd, Dy, and Tb) powders was explored. Post-annealing treatment at 600 °C and 700 °C was employed to modify the microstructures and therefore improve the magnetic properties of the hot-deformed magnets. Doping R70Cu30 alloy powders into the hot-deformed NdFeB magnets is effective in enhancing the coercivity from 15.1 kOe to 16.3–23.6 kOe, depending on the rare-earth elements adopted. The coercivity increment is 1.2 and 4.4 kOe for the magnets doped with Nd70Cu30 and Dy70Cu30 alloy powders, respectively. Most interestingly, Tb70Cu30-doped magnet followed with 700 °C post-annealing exhibits the highest coercivity iHc of 23.6 kOe and the highest coercivity increment of 8.5 kOe. TEM analysis shows that annealing treatment not only modifies the grain boundary of the platelet 2:14:1 phase but also promotes more Tb atoms entering into 2:14:1 crystal. As a result, the coercivity of the magnets is effectively enhanced.
Autors: Y. I. Lee;H. W. Chang;G. Y. Huang;C. W. Shih;W. C. Chang;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Complex Neuromuscular Changes Post-Stroke Revealed by Clustering Index Analysis of Surface Electromyogram
Abstract:
The objective of this paperwas to characterize complex neuromuscular changes induced by a hemisphere stroke through a novel clustering index (CI) analysis of surface electromyogram (EMG). The CI analysis was performed using surface EMG signals collected bilaterally from the thenar muscles of 17 subjects with stroke and 12 age-matched healthy controls during their performance of varying levels of isometric muscle contractions. Compared with the neurologically intact or contralateral muscles, mixed CI patterns were observed in the paretic muscles. Two paretic muscles showed significantly increased CI implying dominant neurogenic changes, whereas three paretic muscles had significantly reduced CI indicating dominantmyopathic changes; the other paretic muscles did not demonstrate a significant CI alternation, likely due to a deficit of descending central drive or a combined effect of neuromuscular factors. Such discrimination of paretic muscles was further highlighted using a modified CI method that emphasizes between-side comparison for each individual subject. The CI findings suggest that there appears to be different central and peripheral processes at work in varying degrees after stroke. This paper provides a convenient and quantitative analysis to assess the nature of neuromuscular changes after stroke, without using any special equipment but conventional surface EMG recording. Such assessment is helpful for the development of appropriate rehabilitation strategies for recovery of motor function.
Autors: Xu Zhang;Zhongqing Wei;Xiaoting Ren;Xiaoping Gao;Xiang Chen;Ping Zhou;
Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Publication date: Nov 2017, volume: 25, issue:11, pages: 2105 - 2112
Publisher: IEEE
 
» Composite Media for Heat Assisted Magnetic Recording
Abstract:
Composite media grains consisting of two discrete magnetic layers with different uniaxial anisotropies, , and Curie temperatures, , were investigated for heat assisted magnetic recording. The maximum switching probability of optimized composite grains exceeded that of single phase grains. As of one layer increased the optimum of the other layer became smaller, tending toward zero in many cases. Leading and trailing edge recording were also compared. Trailing edge recording was superior when the maximum temperature in the grain, , was similar to , but when exceeded leading edge recording performed better.
Autors: Simon John Greaves;Yoshiaki Sonobe;Hiroaki Muraoka;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Comprehensive Modeling to Allow Informed Calculation of DC Traction Systems’ Stray Current Levels
Abstract:
This study is directed toward furnishing stray current modeling on dc traction systems to cope with the variability of a number of influencing parameters. To this end, the archival value of this study is gained by virtue of two new modeling techniques. These new techniques, first, include a Monte—Carlo-based approach to take into account the variability of the dominant factors influencing the conductance per unit length between the track and the earth. Second, a simulation technique that can provide a more robust representation of the conductance per unit length between the track and the earth coupled with uniform and non-uniform soil models is presented in an attempt to comprehensively assess the levels of stray currents leaving a floating dc traction system.
Autors: Charalambos A. Charalambous;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Nov 2017, volume: 66, issue:11, pages: 9667 - 9677
Publisher: IEEE
 
» Compressed Dipoles Resonating at Higher Order Modes With Enhanced Directivity
Abstract:
A compressed dipole operating at higher order modes is proposed and investigated for the enhancement of boresight directivity. Compared with conventional dipoles in free space, the length of the proposed dipole is compressed although the currents on the compressed dipole still sinusoidally distribute. The traces of calculated compressed dipole’s directivity against compressibility show that the directivity of a compressed dipole operating at higher resonant modes is larger than conventional dipoles for the well selected compressibility. This paper shows that printing the dipole onto a piece of dielectric substrate can achieve the desired compressibility. The relationship between the compressibility and relative permittivity of the dielectric slab provides the guidance to realize the selected compressibility. As an example, a thin linear compressed dipole resonating at the third mode is designed, fabricated, and measured to validate the method. The measured broadside gain of the proposed compressed dipole reaches up to 4.6 dBi, 75% or 2.45 dBi higher than a conventional dipole.
Autors: Yu Luo;Zhi Ning Chen;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Nov 2017, volume: 65, issue:11, pages: 5697 - 5701
Publisher: IEEE
 
» Computation of Magnetic Liquid-Free Surface Shape in a Quasi-Homogeneous Magnetic Field With Differential Evolution
Abstract:
This paper presents a method to compute the magnetic liquid-free surface shape of a single spike in a quasi-homogeneous magnetic field produced by the Helmholtz coil. In the Rosensweig instability, the magnetic liquid-free surface deforms in a spike-like shape pattern as a magnetic field above some critical value is applied to the liquid. The free surface of the magnetic liquid is described as a polynomial function in cylindrical coordinates with the applied cylindrical symmetry. To obtain the shape deformation, the system of nonlinear magnetically augmented Young-Laplace equations is solved iteratively. The approach to the solution is executed in two steps. In the first step, magnetic field distribution along the surface is computed by the finite-element method. When magnetic field distribution is known, the second step occurs in which the system of Young-Laplace equations, defined as an optimization problem, is solved by differential evolution.
Autors: Mislav Trbušić;Anton Hamler;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Computational Creativity Exercises: An Avenue for Promoting Learning in Computer Science
Abstract:
Computational thinking and creative thinking are valuable tools both within and outside of computer science (CS). The goal of the project discussed here is to increase students’ achievement in CS courses through a series of computational creativity exercises (CCEs). In this paper, the framework of CCEs is described, and the results of two separate studies on their impact on student achievement are presented. Students in introductory CS courses completed CCEs as part of those courses. Students in Study 1 came from a variety of programs, and students in Study 2 were engineering majors. A profiling approach was used to test whether the impact of the CCEs could be accounted for by differences in students’ motivated and self-regulated engagement. Overall, CCEs had positive impacts on students’ grades and knowledge test scores, and although there were differences in achievement across the profiles, the impact of the CCEs was generally consistent across profiles. The CCEs appear to be a promising way to increase student achievement in introductory CS courses. Implications and directions for future research are discussed.
Autors: Markeya S. Peteranetz;Abraham E. Flanigan;Duane F. Shell;Leen-Kiat Soh;
Appeared in: IEEE Transactions on Education
Publication date: Nov 2017, volume: 60, issue:4, pages: 305 - 313
Publisher: IEEE
 
» Computational Intelligence in Aerospace Science and Engineering [Guest Editorial]
Abstract:
The articles in this special section focus on the use of computational intelligence in the aerospace industry. In an expanding world with limited resources, Computational Intelligence has become a necessity to handle the complexity of systems and processes. The aerospace sector, in particular, has stringent performance requirements on highly complex systems for which solutions are expected to be optimal and reliable at the same time. Computational intelligence techniques have been widely used to find solutions to global single or multi-objective optimization problems, including mixed variables, multi-modal and non-differentiable quantities.
Autors: Massimiliano Vasile;Edmondo Minisci;Ke Tang;
Appeared in: IEEE Computational Intelligence Magazine
Publication date: Nov 2017, volume: 12, issue:4, pages: 12 - 13
Publisher: IEEE
 
» Computationally Tractable Algorithms for Finding a Subset of Non-Defective Items From a Large Population
Abstract:
In the classical non-adaptive group testing setup, pools of items are tested together, and the main goal of a recovery algorithm is to identify the complete defective set given the outcomes of different group tests. In contrast, the main goal of a non-defective subset recovery algorithm is to identify a subset of non-defective items given the test outcomes. In this paper, we present a suite of computationally efficient and analytically tractable non-defective subset recovery algorithms. By analyzing the probability of error of the algorithms, we obtain bounds on the number of tests required for non-defective subset recovery with arbitrarily small probability of error. Our analysis accounts for the impact of both the additive noise (false positives) and dilution noise (false negatives). By comparing with information theoretic lower bounds, we show that the upper bounds on the number of tests are orderwise tight up to a factor, where is the number of defective items. We also provide simulation results that compare the relative performance of the different algorithms and reveal insights into their practical utility. The proposed algorithms significantly outperform the straightforward approaches of testing items one-by-one, and of first identifying the defective set and then choosing the non-defective items from the complement set, in terms of the number of measurements required to ensure a given success rate.
Autors: Abhay Sharma;Chandra R. Murthy;
Appeared in: IEEE Transactions on Information Theory
Publication date: Nov 2017, volume: 63, issue:11, pages: 7149 - 7165
Publisher: IEEE
 
» Computer Generation of High Throughput and Memory Efficient Sorting Designs on FPGA
Abstract:
Accelerating sorting using dedicated hardware to fully utilize the memory bandwidth for Big Data applications has gained much interest in the research community. Recently, parallel sorting networks have been widely employed in hardware implementations due to their high data parallelism and low control overhead. In this paper, we propose a systematic methodology for mapping large-scale bitonic sorting networks onto FPGA. To realize data permutations in the sorting network, we develop a novel RAM-based design by vertically “folding” the classic Clos network. By utilizing the proposed design for data permutation, we develop a hardware generator to automatically build bitonic sorting architectures on FPGAs. For given input size, data width and data parallelism, the hardware generator specializes both the datapath and the control unit for sorting and generates a design in high level hardware description language. We demonstrate trade-offs among throughput, latency and area using two illustrative sorting designs including a high throughput design and a resource efficient design. With a data parallelism of , the high throughput design sorts an -key sequence with latency , throughput results per cycle and uses memory. This achieves optimal memory efficiency (defined as the ratio of throughput to the amount of on-chip memory used by the design) and outperforms the state-of-the-art. Experimental results show that the designs obtained by our proposed hardware generator achieve 49 to 112 percent improvement in energy efficiency and 56 to 430 percent higher memory efficiency compared with the state-of-the-art.
Autors: Ren Chen;Viktor K. Prasanna;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Nov 2017, volume: 28, issue:11, pages: 3100 - 3113
Publisher: IEEE
 
» Computer Graphics Animation for Objective Self-Evaluation
Abstract:
The increased number of students enrolling in dance classes in Japan has resulted in a shortage of qualified instructors, leaving classes to be taught by instructors who are not trained in dance. The authors developed a system specifically designed to help nonqualified dance instructors teach dance using motion capture and animation. The goal is to allow dancers to easily self-evaluate their own performances by comparing it to a standard example.
Autors: Yoko Usui;Katsumi Sato;Shinichi Watabe;
Appeared in: IEEE Computer Graphics and Applications
Publication date: Nov 2017, volume: 37, issue:6, pages: 5 - 9
Publisher: IEEE
 
» Computing the Coupling Resistances in High-Current Instrument Transformers Considering Skin and Proximity Effect
Abstract:
This paper presents a simplified method to compute the frequency-dependent coupling resistances inside high-current instrument transformers (HCTs). The solution of the 1-D Helmholtz equation is used to estimate the losses inside the winding layers dependent on the frequency of the exciting current. The resistive couplings inside the HCT are determined by computing the total winding losses inside the HCT and differentiating the loss equation. An equivalent proximity depth for HCTs is defined by assessing the losses component of skin and proximity effect. This quantity, which only depends on the skin depth and the number of winding layers, enables to estimate the limit beyond which the proximity effect causes high losses inside the winding. A computation example shows the results of the model.
Autors: Christian Jäschke;Peter Schegner;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 7
Publisher: IEEE
 
» Computing the Feasible Spaces of Optimal Power Flow Problems
Abstract:
The solution to an optimal power flow (OPF) problem provides a minimum cost operating point for an electric power system. The performance of OPF solution techniques strongly depends on the problem's feasible space. This paper presents an algorithm that is guaranteed to compute the entire feasible spaces of small OPF problems to within a specified discretization tolerance. Specifically, the feasible space is computed by discretizing certain of the OPF problem's inequality constraints to obtain a set of power flow equations. All solutions to the power flow equations at each discretization point are obtained using the Numerical Polynomial Homotopy Continuation algorithm. To improve computational tractability, “bound tightening” and “grid pruning” algorithms use convex relaxations to preclude consideration of many discretization points that are infeasible for the OPF problem. The proposed algorithm is used to generate the feasible spaces of two small test cases.
Autors: Daniel K. Molzahn;
Appeared in: IEEE Transactions on Power Systems
Publication date: Nov 2017, volume: 32, issue:6, pages: 4752 - 4763
Publisher: IEEE
 
» Computing, Caching, and Communication at the Edge: The Cornerstone for Building a Versatile 5G Ecosystem
Abstract:
This article presents a unified computing, caching, and communication (3C) solution for the upcoming 5G environment that will allow service, content, and function providers to deploy their services/ content/functions near the end users (EUs); to allow network providers to virtually deploy their connectivity services over commodity hardware; and to enable end users to renounce their role as passive 5G stakeholders and become active ones by offering their 3C resources to the 5G ecosystem. In this direction, we foresee the exploitation of a peer-topeer- like middleware/app solution that upon installation will enhance the end user devices with the ability to form virtual fogs capable of providing their 3C resources to the 5G ecosystem. Additionally, we propose the introduction of heterogeneous nodes (e.g., FPGAs and GPUs) at the networks edge, which will boost the processing capabilities without paying a premium in power consumption. This will enable efficient and thorough filtering of the information that makes it all the way up to the cloud. In summary, this article proposes an architecture that exploits and advances the edge and extreme edge 3C paradigms toward enabling the 5G ecosystem to meet its own criterion for low end-to-end latencies and, as such, enable it to provide and sustain high QoS/QoE levels.
Autors: Evangelos K. Markakis;Kimon Karras;Anargyros Sideris;George Alexiou;Evangelos Pallis;
Appeared in: IEEE Communications Magazine
Publication date: Nov 2017, volume: 55, issue:11, pages: 152 - 157
Publisher: IEEE
 
» Conference Calendar [Conference Calendar]
Abstract:
Presents the CIS upcoming calendar of events and meetings.
Autors: Bernadette Bouchon-Meunier;
Appeared in: IEEE Computational Intelligence Magazine
Publication date: Nov 2017, volume: 12, issue:4, pages: 102 - 102
Publisher: IEEE
 
» Conference Report on 2017 IEEE Congress on Evolutionary Computation (IEEE CEC 2017) [Conference Reports]
Abstract:
Presents information on the 2017 IEEE Congress on Evolutionary Computation.
Autors: Jose A. Lozano;
Appeared in: IEEE Computational Intelligence Magazine
Publication date: Nov 2017, volume: 12, issue:4, pages: 5 - 6
Publisher: IEEE
 
» Conference Report on 2017 IEEE International Conference on Fuzzy Systems (FUZZ-IEEE 2017) [Conference Reports]
Abstract:
Presents information on the 2017 IEEE International Conference on Fuzzy Systems.
Autors: Giovanni Acampora;Bruno Siciliano;Hani Hagras;Francisco Herrera;
Appeared in: IEEE Computational Intelligence Magazine
Publication date: Nov 2017, volume: 12, issue:4, pages: 6 - 8
Publisher: IEEE
 
» Congestion-aware local reroute for fast failure recovery in software-defined networks
Abstract:
Although a restoration approach derives a reroute path when failure occurs and greatly reduces forwarding rules in switches compared with a protection approach, software-defined networks (SDNs) induce a long failure recovery process because of frequent flow operations between the SDN controller and switches. Accordingly, it is indispensable to design a new resilience approach to balance failure recovery time and forwarding rule occupation. To this end, we leverage flexible flow aggregation in fast reroute to solve this problem. In the proposed approach, each disrupted traffic flow is reassigned to a local reroute path for the purpose of congestion avoidance. Thus, all traffic flows assigned to the same local reroute path are aggregated into a new “big” flow, and the number of reconfigured forwarding rules in the restoration process is greatly reduced. We first formulate this problem as an integer linear programming model, then design an efficient heuristic named the “congestion-aware local fast reroute” (CALFR). Extensive emulation results show that CALFR enables fast recovery while avoiding link congestion in the post-recovery network.
Autors: Zijing Cheng;Xiaoning Zhang;Yichao Li;Shui Yu;Rongping Lin;Lei He;
Appeared in: IEEE/OSA Journal of Optical Communications and Networking
Publication date: Nov 2017, volume: 9, issue:11, pages: 934 - 944
Publisher: IEEE
 
» Consolidation of (001)-Oriented Fe–Ga Flakes for 3-D Printing of Magnetostrictive Powder Materials
Abstract:
Additive manufacturing (AM) of metallic materials is an emerging technique for the printing of 3-D components using metal powders. The use of thin flakes of magnetostrictive (001)-oriented Fe–Ga powder in a composite matrix for the design of pressure and strain sensors has been demonstrated. This paper extends that work and presents a preliminary evaluation of two methods for the consolidation of magnetostrictive Fe–Ga alloy flakes, using a hot press and arc melting. Flake-shaped powders of Fe80Ga20 and Fe73Ga27 alloys were prepared with varying particle sizes up to in diameter using a high energy wet ball milling process. The surfaces of the flakes produced were predominantly parallel to the (001) crystallographic plane. Hot pressed Fe–Ga disk samples at 850 °C showed increases of packing density and saturation magnetization with an increase of the particle size because higher thickness to diameter aspect ratios in the flakes facilitated ordering of flakes whereby they more easily defaulted to sitting on one another in layers. We also employed arc melting and binder infiltration techniques to demonstrate the potential suitability of the oriented flake form of this magnetostrictive alloy for AM using 3-D printing methods.
Autors: Suok-Min Na;John Galuardi;Alison B. Flatau;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Constrained Band Subset Selection for Hyperspectral Imagery
Abstract:
This letter extends the constrained band selection (CBS) technique to constrained band subset selection (CBSS) in a similar manner that constrained energy minimization has been extended to linearly constrained minimum variance. CBSS constrains multiple bands as a band subset as opposed to CBS constraining a single band as a singleton set. To achieve this goal, CBSS requires a strategy to search for an optimal band subset, while CBS does not. In this letter, two new sequential algorithms, referred to as sequential CBSS and successive CBSS, which do not exist in CBS are derived for CBSS to find desired band subsets and to avoid exhaustive search.
Autors: Lin Wang;Hisao-Chi Li;Bai Xue;Chein-I Chang;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Nov 2017, volume: 14, issue:11, pages: 2032 - 2036
Publisher: IEEE
 
» Constrained Deep Weak Supervision for Histopathology Image Segmentation
Abstract:
In this paper, we develop a new weakly supervised learning algorithm to learn to segment cancerous regions in histopathology images. This paper is under a multiple instance learning (MIL) framework with a new formulation, deep weak supervision (DWS); we also propose an effective way to introduce constraints to our neural networks to assist the learning process. The contributions of our algorithm are threefold: 1) we build an end-to-end learning system that segments cancerous regions with fully convolutional networks (FCNs) in which image-to-image weakly-supervised learning is performed; 2) we develop a DWS formulation to exploit multi-scale learning under weak supervision within FCNs; and 3) constraints about positive instances are introduced in our approach to effectively explore additional weakly supervised information that is easy to obtain and enjoy a significant boost to the learning process. The proposed algorithm, abbreviated as DWS-MIL, is easy to implement and can be trained efficiently. Our system demonstrates the state-of-the-art results on large-scale histopathology image data sets and can be applied to various applications in medical imaging beyond histopathology images, such as MRI, CT, and ultrasound images.
Autors: Zhipeng Jia;Xingyi Huang;Eric I-Chao Chang;Yan Xu;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Nov 2017, volume: 36, issue:11, pages: 2376 - 2388
Publisher: IEEE
 
» Constraint Programming Approach for Scheduling Jobs With Release Times, Non-Identical Sizes, and Incompatible Families on Parallel Batching Machines
Abstract:
We study a parallel batch-scheduling problem that involves the constraints of different job release times, non-identical job sizes, and incompatible job families, is addressed. Mixed integer programming and constraint programming (CP) models are proposed and tested on a set of common problem instances from a paper in the literature. Then, we compare the performance of the models with that of a variable neighborhood search (VNS) heuristic from the same paper. Computational results show that CP outperforms VNS with respect to solution quality and run time by 3.4%–6.8% and 47%–91%, respectively. When compared to optimal solutions, the results demonstrate CP is capable of generating a near optimal solution in a short amount of time.
Autors: Andy Ham;John W. Fowler;Eray Cakici;
Appeared in: IEEE Transactions on Semiconductor Manufacturing
Publication date: Nov 2017, volume: 30, issue:4, pages: 500 - 507
Publisher: IEEE
 
» Constraint Qualification Based Detection Method for Nodal Price Multiplicity
Abstract:
This paper proposes a fast, standalone method for detecting multiple dual solutions (MDS) of the market dispatch problem. Using linear independence constraint qualification conditions and matrix theory, we characterize the conditions for MDS and develop a procedure for their detection. Our procedure exploits the structure of the market dispatch problem to improve computational efficiency. We demonstrate our method on eight nodal pricing scenarios, in four test systems.
Autors: Donghan Feng;Chang Liu;Zeyu Liu;Liang Zhang;Yangzhi Ding;Clay Campaigne;
Appeared in: IEEE Transactions on Power Systems
Publication date: Nov 2017, volume: 32, issue:6, pages: 4968 - 4969
Publisher: IEEE
 
» Construction of a Bit Stream Using Telegraphic Switching of a Two-Input Magnetic Tunnel Junction
Abstract:
Stochastic computing with probabilistic bit streams is a useful computing method due to its advantage of a higher degree of error tolerance than the conventional binary system. To achieve computational efficiency, electronic devices with an inherent stochastic nature have been explored for integration into a stochastic computing system. In this paper, we demonstrate probabilistic bit streams obtained from the telegraphic switching of a two-input magnetic tunnel junction (MTJ). Extension of the input configuration provides an advantage in architectural comparability for applying to a practical computing circuit. We also show that an MTJ can be a generic stochastic device, whose output directly constructs bit streams representing the probabilistic weight according to two independent progammable inputs, namely, the applied magnetic field and the current.
Autors: Gi Yoon Bae;Dong Ik Suh;Young-jae Kim;Hyungjune Lee;Wanjun Park;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Contactless Piston Position Transducer With Axial Excitation
Abstract:
Existing piston position transducers require either drilling precise hole into the piston bar, or mounting permanent magnets or measuring device inside the pressurized cylinder. We present a new solution for aluminum pneumatic cylinders, which uses the ferromagnetic bar inside the solenoid as a marker and linear array of fluxgate sensors as a scale. Instead of relying on dc remanence we use active ac excitation; the reading is resistant against external fields, both dc and ac. Using sensor array allows to compensate for temperature effects. The linear stroke of the individual sensor is 40 mm, so that array density should be about 30 mm. 1 mm position resolution is achievable. The weak point of the new transducer is the response time: for fast moving pistons the excitation frequency should be high, which leads to weaker signal and lower resolution.
Autors: Pavel Ripka;Andrey Chirtsov;Vaclav Grim;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Containment and Consensus-Based Distributed Coordination Control to Achieve Bounded Voltage and Precise Reactive Power Sharing in Islanded AC Microgrids
Abstract:
This paper presents a novel distributed approach to achieve both bounded voltage and accurate reactive power sharing regulation in ac microgrid. The coupling/trade-off effects between bus voltages and reactive power sharing regulation are first analyzed in detail to provide a guideline for coordinated control design. Furthermore, a containment and consensus-based distributed coordination controller is proposed, by which the bus voltage magnitudes can be bounded within a reasonable range, instead of only controlling average voltage value. Furthermore, the accurate reactive power sharing between distributed generators can be achieved simultaneously. Then, a detailed small-signal model is developed to analyze the stability of the system and the sensitivity of different parameters. Experimental results are presented and compared, where the controller performance, robust performance under communication failure, and plug-and-play operation are successfully verified.
Autors: Renke Han;Lexuan Meng;Giancarlo Ferrari-Trecate;Ernane Antônio Alves Coelho;Juan C. Vasquez;Josep M. Guerrero;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Nov 2017, volume: 53, issue:6, pages: 5187 - 5199
Publisher: IEEE
 
» Context-Aware Software Variability through Adaptable Interpreters
Abstract:
Dynamic adaptation to the execution context is desirable in software that operates in an evolving environment. Context-oriented programming (COP) languages address behavioral variability from the programming-language perspective. COP has proven to be a valid approach when software is developed from scratch. However, it might require invasive, error-prone modifications when contextual variability is introduced to existing software written in non-COP languages, especially when variability is implicit in language constructs. A proposed approach moves variability support from the language to the language implementation level. This enables contextual variability in any application independently of whether the underlying language supports COP. A Neverlang-based prototype implementation illustrates this approach.
Autors: Walter Cazzola;Albert Shaqiri;
Appeared in: IEEE Software
Publication date: Nov 2017, volume: 34, issue:6, pages: 83 - 88
Publisher: IEEE
 
» Continuous Asymptotically Tracking Control for a Class of Nonaffine-in-Input System With Nonvanishing Disturbance
Abstract:
In this paper, we explore the possibility of designing a continuous controller for a class of nonaffine system to achieve asymptotically tracking results with robustness to system uncertainties, unvanishing disturbances, and unknown control effectiveness. A robust integral of the sign of the error design is formulated to search a robust control for the nonaffine dynamics, while a time-varying gain of Nussbaum-type-function (NTF) is augmented to estimate the unknown direction and magnitude for control effectiveness. A second-order filter is employed to proceed the design when the NTF gain is involved without using any unmeasurable signals. Rigorous analysis shows that the proposed controller can asymptotically stabilizes the closed-loop system and the output tracking error. Simulation results on a Duffing–Holmes chaotic system demonstrate the effectiveness of the proposed approach.
Autors: Bin Xian;Yao Zhang;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Nov 2017, volume: 62, issue:11, pages: 6019 - 6025
Publisher: IEEE
 
» Continuous Sampled-Data Observer Design for Nonlinear Systems With Time Delay Larger or Smaller Than the Sampling Period
Abstract:
This technical note addresses the problem of high gain observer design for a class of triangular nonlinear systems with sampled and delayed output measurements. The transmission delay may be larger or smaller than the sampling period. Firstly, a class of hybrid systems are introduced, and sufficient conditions are proposed to guarantee that the hybrid systems are globally and exponentially stable. Then, a continuous-discrete observer is designed for the nonlinear systems. Based on these sufficient conditions and a specially constructed Lyapunov-Krasovskii functional, it is shown that the observation errors globally and exponentially converge to the origin. Finally, an illustrative example is used to verify the validity of the proposed design methods.
Autors: Daoyuan Zhang;Yanjun Shen;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Nov 2017, volume: 62, issue:11, pages: 5822 - 5829
Publisher: IEEE
 
» Contrast-Enhanced Magnetic Resonance Imaging of Gastric Emptying and Motility in Rats
Abstract:
The assessment of gastric emptying and motility in humans and animals typically requires radioactive imaging or invasive measurements. Here, we developed a robust strategy to image and characterize gastric emptying and motility in rats based on contrast-enhanced magnetic resonance imaging (MRI) and computer-assisted image processing. The animals were trained to naturally consume a gadolinium-labeled dietgel while bypassing any need for oral gavage. Following this test meal, the animals were scanned under low-dose anesthesia for high-resolution T1-weighted MRI in 7 Tesla, visualizing the time-varying distribution of the meal with greatly enhanced contrast against non-gastrointestinal (GI) tissues. Such contrast-enhanced images not only depicted the gastric anatomy, but also captured and quantified stomach emptying, intestinal filling, antral contraction, and intestinal absorption with fully automated image processing. Over four postingestion hours, the stomach emptied by 27%, largely attributed to the emptying of the forestomach rather than the corpus and the antrum, and most notable during the first 30 min. Stomach emptying was accompanied by intestinal filling for the first 2 h, whereas afterward intestinal absorption was observable as cumulative contrast enhancement in the renal medulla. The antral contraction was captured as a peristaltic wave propagating from the proximal to distal antrum. The frequency, velocity, and amplitude of the antral contraction were on average 6.34 ± 0.07 contractions per minute, 0.67 ± 0.01 mm/s, and 30.58 ± 1.03%, respectively. These results demonstrate an optimized MRI-based strategy to assess gastric emptying and motility in healthy rats, paving the way for using this technique to understand GI diseases, or test new therapeutics in rat models.
Autors: Kun-Han Lu;Jiayue Cao;Steven Thomas Oleson;Terry L. Powley;Zhongming Liu;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Nov 2017, volume: 64, issue:11, pages: 2546 - 2554
Publisher: IEEE
 
» Control Algorithm for Soft Start of Split-AC-Switched-Reluctance Motor Drives
Abstract:
This paper proposes a control method to balance capacitor voltages in a four-switch single-stage two-phase-switched-reluctance motor drive with integrated power factor correction during startup and at low speeds. Initial alignment process is incorporated for switched-reluctance machine before startup. However, the phase currents are unbalanced during that time. This will cause overvoltage on dc capacitors in split-ac configuration leadings to their failure. This problem also exists when the motor speed is very low, as observed in the startup process of compressors. Based on a unified model, an effective control method is proposed to eliminate the voltage difference between the capacitors. This method does not require any additional circuits or components. It also does not affect the performance during normal mode of operation. Experiments are performed to verify the feasibility of the control method.
Autors: Dingyi He;Wen Cai;Fan Yi;Adam Clark;Jingchen Liang;Lei Gu;Babak Fahimi;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Nov 2017, volume: 53, issue:6, pages: 5479 - 5488
Publisher: IEEE
 
» Control and Release in Complex Relationships
Abstract:
Artist James Alan Smith is driven to involve himself in the creative process, whether through coding or visual art. The effect of his abstract and representation pieces is extraordinary and mysterious, and each encourages viewers to see the complex relationships between the various layers.
Autors: Gary Singh;
Appeared in: IEEE Computer Graphics and Applications
Publication date: Nov 2017, volume: 37, issue:6, pages: 3 - 4
Publisher: IEEE
 
» Control of Domain Structure in Artificial Ni Wires Fabricated on an LiNbO3 Substrate
Abstract:
We demonstrated control of magnetic domain structure formation within micro-scale polycrystalline Ni wires fabricated on a single crystalline LiNbO3 substrate. We observed the domain structures using X-ray magnetic circular dichroism-photoemission electron microscopy at SPring-8 BL25SU and BL17SU. Both zebra-stripe domain and ordinary single domain structures can be formed in the Ni wire in control of alignment of the wire onto the substrate. The result suggests that magnetoelastic effects from pizoelectristic substrates can strongly influence the magnetization alignment, overwhelming their shape magnetic anisotropy. The formation of zebra-stripe domain structure can be qualitatively explained by the micromagnetic simulation under the assumption of the magnetic anisotropy perpendicular to the longitudinal axis of wire. Our finding provides a way to control the domain structure and magnetization reversal using the combination of shape magnetic anisotropy and strain-induced anisotropy.
Autors: A. Yamaguchi;T. Ohkochi;A. Yasui;T. Kinoshita;K. Yamada;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Control of Interlayer Exchange Coupling and Its Impact on Spin–Torque Switching of Hybrid Free Layers With Perpendicular Magnetic Anisotropy
Abstract:
To ensure data retention in high-density spin-transfer-torque magnetic random access memory (STT-MRAM), a [Co/Ni]-CoFeB hybrid free layer (HFL) with a high energy barrier was proposed for small-dimension magnetic tunnel junctions. Its behavior on device level, however, needs further research. In particular, the impact of the interlayer that provides magnetic coupling between the [Co/Ni] multilayers and the CoFeB on the spin-torque switching is not known. In this paper, both macrospin modeling and micromagnetic simulations are used to study the influence of interlayer exchange coupling (IEC) on the switching behavior of the HFL for different device sizes. Both methods provide the optimal value for the coupling constant () and switching current (), as well as their size dependence, to realize HFL switching with the lowest energy consumption. In addition to the simulations, control of the IEC in the HFL by introducing a TaCoFeB interlayer and a Co termination layer on the [Co/Ni] part is shown, and a broad range is achieved without compromising the magnetotransport properties of the stacks. Both simulations and experimental work show that the HFL design with adequate interlayer engineering can be a viable route for high-density STT-MRAM devices and other spintronic applications.
Autors: Enlong Liu;Adrien Vaysset;Johan Swerts;Thibaut Devolder;Sebastien Couet;Sofie Mertens;Tsann Lin;Sven Van Elshocht;Jo De Boeck;Gouri Sankar Kar;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Controls for Smart Grids: Architectures and Applications
Abstract:
Control is and will continue to be a key discipline for realizing the objectives of smart grid initiatives. Research in control science and engineering is not limited to one or a few application concepts but is pervasive across the smart grid ecosystem. The principal contribution of this paper is to review, from a system-architectural perspective, how control enables smart grid applications. Application “templates” are presented for direct load control, automated demand response, microgrid optimization, control for distribution grids, wide-area control, and market-centric control. Technological developments, including in power electronics, that are enabling smart grid control research and applications are also itemized and two cross-cutting needs/opportunities for future research discussed. We conclude with a summary of a recent status report on the progress that has been made in the United States, noting also the challenges to further progress, in renewable generation, energy efficiency, and carbon reduction.
Autors: Tariq Samad;Anuradha M. Annaswamy;
Appeared in: Proceedings of the IEEE
Publication date: Nov 2017, volume: 105, issue:11, pages: 2244 - 2261
Publisher: IEEE
 
» Convex Mapping Formulations Enabling Optimal Power Split and Design of the Electric Drivetrain in All-Electric Vehicles
Abstract:
All-electric drivetrains have been identified as a promising alternative to contemporary hybrid vehicle technology. Extending their operational range is key and can be achieved by means of design procedures based on high-fidelity models capturing the dynamical behavior of the electric drivetrain. This paper proposes a dedicated power split embodying a dual electric drive and a model-based strategy to design the drivetrain. Advancements are required in model-based design that can cope with the complexity of the computationally expensive and high-dimensional parametric design problems. We propose a nested optimization approach wherein parameter exploration is attained using an evolutionary algorithm and the optimal power flows are determined by abstracting the high-fidelity behavioral models into appropriate convex loss mappings. This allows for an accelerated design procedure based on convex optimization without compromising accuracy. We size an electric drivetrain for maximal range extension, consisting of a battery stack, buck–boost converter, inverter and mechanically coupled induction motors subjected to variable load conditions. A tractable convex formulation is obtained and optimization time is reduced by 99.3% compared to the traditional approach without convexification. Optimal control of the incorporated power split increases the operational range by 0.7% compared to the isolated operation of a single motor. The proposed methodology thus paves the way for extensive designs of drivetrains and complex mechatronic systems in a general context.
Autors: Arne De Keyser;Matthias Vandeputte;Guillaume Crevecoeur;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Nov 2017, volume: 66, issue:11, pages: 9702 - 9711
Publisher: IEEE
 
» Convex Optimization-Based Signal Detection for Massive Overloaded MIMO Systems
Abstract:
This paper proposes signal detection schemes for massive multiple-input multiple-output (MIMO) systems, where the number of receive antennas is less than that of transmitted streams. Assuming practical baseband digital modulation and taking advantage of the discreteness of transmitted symbols, we formulate the signal detection problem as a convex optimization problem, called sum-of-absolute-value (SOAV) optimization. Moreover, we extend the SOAV optimization into the weighted-SOAV (W-SOAV) optimization and propose an iterative approach to solve the W-SOAV optimization with updating the weights in the objective function. Furthermore, for coded MIMO systems, we also propose a joint detection and decoding scheme, where log likelihood ratios of transmitted symbols are iteratively updated between the MIMO detector and the channel decoder. In addition, a theoretical performance analysis is provided in terms of the upper bound of the size of the estimation error obtained with the W-SOAV optimization. Simulation results show that the bit error rate performance of the proposed scheme is better than that of conventional schemes, especially in large-scale overloaded MIMO systems.
Autors: Ryo Hayakawa;Kazunori Hayashi;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Nov 2017, volume: 16, issue:11, pages: 7080 - 7091
Publisher: IEEE
 
» Convolutional Neural Networks for Inverse Problems in Imaging: A Review
Abstract:
In this article, we review recent uses of convolutional neural networks (CNNs) to solve inverse problems in imaging. It has recently become feasible to train deep CNNs on large databases of images, and they have shown outstanding performance on object classification and segmentation tasks. Motivated by these successes, researchers have begun to apply CNNs to the resolution of inverse problems such as denoising, deconvolution, superresolution, and medical image reconstruction, and they have started to report improvements over state-of-the-art methods, including sparsity-based techniques such as compressed sensing. Here, we review the recent experimental work in these areas, with a focus on the critical design decisions.
Autors: Michael T. McCann;Kyong Hwan Jin;Michael Unser;
Appeared in: IEEE Signal Processing Magazine
Publication date: Nov 2017, volume: 34, issue:6, pages: 85 - 95
Publisher: IEEE
 
» Coordinated Supervisory Control of Multi-Terminal HVDC Grids: A Model Predictive Control Approach
Abstract:
A coordinated supervisory control scheme for future multi-terminal high-voltage direct-current (HVDC) grids is proposed. The purpose is to supervise the grid and take appropriate actions to ensure power balance and prevent or remove voltage or current limit violations. First, using DC current and voltage measurements, the power references of the various Voltage Source Converters are updated according to participation factors. Next, the setpoints of the converters are smoothly adjusted to track those power references, while avoiding or correcting limit violations. The latter function resorts to model predictive control and a sensitivity model of the system. The efficiency of the proposed scheme has been tested through dynamic simulations of a five-terminal HVDC grid interconnecting two asynchronous AC areas and a wind farm.
Autors: Lampros Papangelis;Marie-Sophie Debry;Patrick Panciatici;Thierry Van Cutsem;
Appeared in: IEEE Transactions on Power Systems
Publication date: Nov 2017, volume: 32, issue:6, pages: 4673 - 4683
Publisher: IEEE
 
» Core-Shell Magnetic Structure of La1–xSrxMnO $_{3+delta }$ Nanocrystallites
Abstract:
Magnetic La1–xSrxMnO particles of composition and average size of 40 nm have been prepared from the oxidizing flux of sodium nitrite at . Detailed magnetic and neutron diffraction measurements have been performed on raw nanoparticles and particles subjected to mild acid leaching. Based on these experiments and X-ray fluorescence analysis of the respective products, we conclude on the core-shell magnetic structure of the molten-salt-prepared particles, consisting of ferromagnetic (FM) ordering in the interior and A-type antiferromagnetic (AFM) ordering in the intermediate shell just below the outermost, magnetically disordered layer. The reason for such complex arrangement, unprecedented in sol-gel-prepared manganite nanoparticles of the same composition, is in a certain radial distribution of La, Sr cations, and an increased oxygen stoichiometry related to the presence of extra oxygen atoms covalently bound at the particle surface. The acid leaching, performed by consecutive treatments with ice-cold solutions of dilute nitric acid and citric acid, removes the overoxidized surface and some outer Sr-richer layers, decreasing the composition to . As a result, the AFM ordering is almost completely suppressed while FM ordering is preserved in the leached nanoparticles.
Autors: Nadezhda M. Belozerova;Sergey E. Kichanov;Denis P. Kozlenko;Ondřej Kaman;Zdeněk Jirák;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Correcting Biased Evaporation in CloudSat Warm Rain
Abstract:
The CloudSat mission’s Cloud Profiling Radar has provided the first global-scale estimates of light rainfall from warm marine clouds. Because surface radar reflection prevents hydrometeor detection below ~720 m, the CloudSat 2C-RAIN-PROFILE retrieval uses an evaporation–sedimentation model to extend its profile estimates to the surface. We use in situ radar measurements from the ship-based Marine ARM GPCI Investigation of Clouds (MAGIC) campaign in the Northeastern subtropical Pacific, which sampled a diverse set of shallow marine cloud regimes, to evaluate the evaporation–sedimentation model near the surface. We suggest an empirical bias correction, which can be applied to the 2C-RAIN-PROFILE retrieval. Before this correction, the evaporation–sedimentation model produced a mean surface rain rate bias along the MAGIC transect of 57%; after correction, this bias was effectively eliminated. We also present the evidence of the validity of this bias correction across regimes in the MAGIC region, and also in the southeast subtropical Pacific, where the magnitude of the mean bias for surface rain due to the evaporation–sedimentation model is reduced by a factor of 4.
Autors: Peter Kalmus;Matthew Lebsock;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Nov 2017, volume: 55, issue:11, pages: 6207 - 6217
Publisher: IEEE
 
» Correction to “Closed-Form Jones Matrix of Dual-Polarized Inverted-Vee Dipole Antennas over Lossy Ground”
Abstract:
In the Appendix of the paper [1, p. 33], the authors would like to make the following correction.
Autors: R. A. C. Baelemans;A. T. Sutinjo;P. J. Hall;A. B. Smolders;M. J. Arts;E. de Lera Acedo;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Nov 2017, volume: 65, issue:11, pages: 6198 - 6198
Publisher: IEEE
 
» Correction to “Cyclic Orbit Codes”
Abstract:
We would like to thank Mahdieh Hakimi Poroch and Ali Asghar Talebi for pointing out two errors in Proposition 28 and Theorem 29 of the original paper [1]. The correct formulation for these two statements is as follows.
Autors: Anna-Lena Horlemann-Trautmann;Felice Manganiello;Michael Braun;Joachim Rosenthal;
Appeared in: IEEE Transactions on Information Theory
Publication date: Nov 2017, volume: 63, issue:11, pages: 7616 - 7616
Publisher: IEEE
 
» Correction to “Cyclic Orbit Codes” [Nov 13 7386-7404]
Abstract:
We would like to thank Mahdieh Hakimi Poroch and Ali Asghar Talebi for pointing out two errors in Proposition 28 and Theorem 29 of the original paper [1]. The correct formulation for these two statements is as follows.
Autors: Anna-Lena Horlemann-Trautmann;Felice Manganiello;Michael Braun;Joachim Rosenthal;
Appeared in: IEEE Transactions on Information Theory
Publication date: Nov 2017, volume: 63, issue:11, pages: 7616 - 7616
Publisher: IEEE
 
» Corrections to “Change Detection in Full and Dual Polarization, Single- and Multi-Frequency SAR Data”
Abstract:
When the covariance matrix formulation is used for multi-look polarimetric synthetic aperture radar (SAR) data, the complex Wishart distribution applies. Based on this distribution a test statistic for equality of two complex variance-covariance matrices and an associated asymptotic probability of obtaining a smaller value of the test statistic are given. In a case study airborne EMISAR C- and L-band SAR images from the spring of 1998 covering agricultural fields and wooded areas near Foulum, Denmark, are used in single- and bi-frequency, bi-temporal change detection with full and dual polarimetry data.
Autors: Allan A. Nielsen;Knut Conradsen;Henning Skriver;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Nov 2017, volume: 10, issue:11, pages: 5143 - 5144
Publisher: IEEE
 
» Corrections to “A New Efficient Unconditionally Stable Finite-Difference Time-Domain Solution of the Wave Equation”
Abstract:
In [1], , , and were mistyped. The correct values are begin{align*} r_{x}=&frac {sqrt {2} Delta t}{sqrt {varepsilon mu } Delta x} sin {left ({frac { k_{x} Delta x}{2} }right )}\ r_{y}=&frac {sqrt {2} Delta t}{sqrt {varepsilon mu } Delta y} sin {left ({frac { k_{y} Delta y}{2} }right )}\ mathbf {G_{M}}=&begin{matrix} left [{ begin{matrix} big (1+r_{x}^{2}big )(xi ^{2}+1)-2xi &quad -(2r_{x} r_{y}) xi \ -(2r_{x} r_{y}) xi &quad big (1+r_{y}^{2}big )(xi ^{2}+1)-2xi end{matrix} }right ]. end{matrix} end{align*}
Autors: Seyed-Mojtaba Sadrpour;Vahid Nayyeri;Mohammad Soleimani;Omar M. Ramahi;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Nov 2017, volume: 65, issue:11, pages: 6197 - 6197
Publisher: IEEE
 
» Corrections to “High-Gain Filtering Patch Antenna without Extra Circuit”
Abstract:
We would like to correct the values listed in Table I and two typos in Fig. 14 in the communication [1] as follows.
Autors: Xiu Yin Zhang;Wen Duan;Yong-Mei Pan;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Nov 2017, volume: 65, issue:11, pages: 6196 - 6196
Publisher: IEEE
 
» Corrections to “Relativistic Aspects of Plane Wave Scattering by a Perfectly Conducting Half-Plane With Uniform Velocity Along an Arbitrary Direction”
Abstract:
In a recent paper [1], there was a typo in (13), which should read as a scalar equation for the -component of in the form begin{equation*} tilde {E}_{ {z}} {tilde {H}_{ {z}}} = F(tilde {xi }^{i}) , tilde {E}_{ {z}}^{i} {tilde {H}_{ {z}}^{i}} + F(tilde {xi }^{r}) tilde {E}_{ {z}}^{r} {tilde {H}_{ {z}}^{r}} end{equation*} from which the remaining field components may be obtained. The full vector equation for the electric field is then given by begin{align*} tilde {mathbf {E}}=&F(tilde {xi }^{i}) tilde {mathbf {E}}^{i} + F(tilde {xi }^{r}) tilde {mathbf {E}}^{r} + frac {e^{i pi /4}}{sqrt { 2 pi tilde {k} tilde {rho } sin tilde {theta }_{0} }} e^{i tilde {k} (tilde {rho } sin tilde {theta }_{0} -tilde { {z}} cos tilde {theta }_{0})} \[3pt]× bigg { cos frac {tilde {phi }-tilde {phi }_{0}}{2} left [{ left ({ tilde {mathbf {E}}^{i}_{0} cdot hat {tilde { {z}}} }right) hat {tilde { {z}}} - tilde {mathbf {E}}^{i}_{0} }right ] +sin frac {tilde {phi }-tilde {phi }_{0}}{2} , hat {tilde { {z}}} times tilde {mathbf {E}}^{i}_{0} \[4pt]&+,cos frac {tilde {phi }+tilde {phi }_{0}}{2} left [{ left ({ tilde {mathbf {E}}^{r}_{0} cdot hat {tilde { {z}}} }right) hat {tilde { {z}}} - tilde {mathbf {E}}^{r}_{0} }right ] +sin frac {tilde {phi }+tilde {phi }_{0}}{2} , hat {tilde { {z}}} times tilde {mathbf {E}}^{r}_{0} bigg } end{align*} where denotes the incident (reflected) electric field ampli- ude at the edge of the half-plane in frame . In addition, in (24) should read as , yielding begin{align*} tilde {bar {bar {F}}}_{re}=&dfrac {tilde {Q}}{c} \× ! begin{bmatrix}! 0 !&quad ! -!tilde {B}_{e} sin dfrac {tilde {phi }}{2} !&quad ! tilde {B}_{e} cos dfrac {tilde {phi }}{2} !&quad ! 0 \ tilde {B}_{e} sin dfrac {tilde {phi }}{2} !&quad ! 0 !&quad ! 0 !&quad ! -tilde {B}_{h} sin dfrac {tilde {phi }}{2} \ -tilde {B}_{e} cos dfrac {tilde {phi }}{2} !&quad ! 0 !&quad ! 0 !&quad ! tilde {B}_{h} cos dfrac {tilde {phi }}{2} \ 0 !&quad ! tilde {B}_{h} sin dfrac {tilde {phi }}{2} !&quad ! -tilde {B}_{h} cos dfrac {tilde {phi }}{2} !&quad ! 0 end{bmatrix}!. end{align*} None of the above-mentioned remarks affect the calculations and results presented in [1].
Autors: Guilherme S. Rosa;Julio L. Nicolini;Flavio J. V. Hasselmann;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Nov 2017, volume: 65, issue:11, pages: 6199 - 6199
Publisher: IEEE
 
» Corrections to “Weight Distribution of Cosets of Small Codes With Good Dual Properties”
Abstract:
We provide two corrections to [1] which do not affect the validity of any of the the reported results. First, we note that Conjecture 9 on page 6497 is not correct; a counter example follows from Cohen’s theorem [2] which asserts the existence of linear codes with covering radius up to the sphere-covering bound. The second correction is related to the “Proof of Theorem 2 using Theorem 5” on page 6496. In that proof, the -point Discrete Fourier Transform (DFT) should be on points. The other steps of the proof hold without modification. We reproduce below the corrected proof with the needed modifications in bold. The issue with the -point DFT is that it makes Identity (1) below incorrect for .
Autors: Louay Bazzi;
Appeared in: IEEE Transactions on Information Theory
Publication date: Nov 2017, volume: 63, issue:11, pages: 7615 - 7615
Publisher: IEEE
 
» Correlation Between Rotor Vibration and Mechanical Stress in Ultra-High-Speed Permanent Magnet Synchronous Motors
Abstract:
This paper investigates the correlation between rotor vibration and mechanical stress in ultra-high-speed permanent magnet synchronous motors (PMSMs); the mechanical stress generated in the PM and the rotational vibration when the PMSM rotates at high speeds were evaluated. Two PM rotors that have the same performance characteristics but different shrink fits were studied, and the vibration of these two PM rotors was analyzed. Furthermore, to evaluate the correlation between mechanical stress and vibration, the rotor design parameters, such as sleeve thickness and shrink fit, were varied. Based on the analysis results, a real-world model was developed and an experiment was conducted to test the vibration of these two rotors; the validity of our results was verified by performing experiments.
Autors: Ji-Hun Ahn;Jang-Young Choi;Cheol Hoon Park;Cheol Han;Chang-Woo Kim;Tae-Gwang Yoon;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 6
Publisher: IEEE
 
» Cortical Brain–Computer Interface for Closed-Loop Deep Brain Stimulation
Abstract:
Essential tremor is the most common neurological movement disorder. This progressive disease causes uncontrollable rhythmic motions—most often affecting the patient’sdominant upper extremity—thatoccur during volitional movement and make it difficult for the patient to perform everyday tasks. Medication may also become ineffective as the disorder progresses. For many patients, deep brain stimulation (DBS) of the thalamus is an effective means of treating this condition when medication fails. In current use, however, clinicians set the patient’s stimulator to apply stimulation at all times—whether it is needed or not. This practice leads to excess power use, and more rapid depletion of batteries that require surgical replacement. In this paper, for the first time, neural sensing of movement (using chronically implanted cortical electrodes) is used to enable or disable stimulation for tremor. Therapeutic stimulation is delivered onlywhen the patient is actively using their effected limb, thereby reducing the total stimulation applied, and potentially extending the lifetime of surgically implanted batteries. This paper, which involves both implanted and external subsystems, paves the way for fully-implanted closed-loop DBS in the future.
Autors: Jeffrey A. Herron;Margaret C. Thompson;Timothy Brown;Howard Jay Chizeck;Jeffrey G. Ojemann;Andrew L. Ko;
Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Publication date: Nov 2017, volume: 25, issue:11, pages: 2180 - 2187
Publisher: IEEE
 
» Cost-Aware Big Data Processing Across Geo-Distributed Datacenters
Abstract:
With the globalization of service, organizations continuously produce large volumes of data that need to be analysed over geo-dispersed locations. Traditionally central approach that moving all data to a single cluster is inefficient or infeasible due to the limitations such as the scarcity of wide-area bandwidth and the low latency requirement of data processing. Processing big data across geo-distributed datacenters continues to gain popularity in recent years. However, managing distributed MapReduce computations across geo-distributed datacenters poses a number of technical challenges: how to allocate data among a selection of geo-distributed datacenters to reduce the communication cost, how to determine the Virtual Machine (VM) provisioning strategy that offers high performance and low cost, and what criteria should be used to select a datacenter as the final reducer for big data analytics jobs. In this paper, these challenges is addressed by balancing bandwidth cost, storage cost, computing cost, migration cost, and latency cost, between the two MapReduce phases across datacenters. We formulate this complex cost optimization problem for data movement, resource provisioning and reducer selection into a joint stochastic integer nonlinear optimization problem by minimizing the five cost factors simultaneously. The Lyapunov framework is integrated into our study and an efficient online algorithm that is able to minimize the long-term time-averaged operation cost is further designed. Theoretical analysis shows that our online algorithm can provide a near optimum solution with a provable gap and can guarantee that the data processing can be completed within pre-defined bounded delays. Experiments on WorldCup98 web site trace validate the theoretical analysis results and demonstrate that our approach is close to the offline-optimum performance and superior to some representative approaches.
Autors: Wenhua Xiao;Weidong Bao;Xiaomin Zhu;Ling Liu;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Nov 2017, volume: 28, issue:11, pages: 3114 - 3127
Publisher: IEEE
 
» Cost-Effective Vernier Permanent-Magnet Machine With High Torque Performance
Abstract:
This paper presents a cost-effective five-phase vernier permanent-magnet (VPM) machine with fault tolerance for direct-drive applications, which has hybrid magnet material in both stator and rotor. By adopting unipolar rare-earth PM in rotor, the amount of rare-earth PM is reduced by half and the flux leakage between PMs is much reduced. Besides, the unipolar ferrite PM is assisted between flux-modulation poles to further improve the flux in stator teeth. Moreover, the torque performance and PM utilization rate are further improved due to the optimization of stator teeth in the proposed machine. The time-stepping finite-element method is used to evaluate the performance of proposed VPM machine in comparison with bipolar and unipolar ones. The results show that the proposed VPM machine not only remains the advantage of fault tolerance, but also significantly improves the torque density and reduces torque ripple simultaneously with considerable less consumption of rare-earth PM.
Autors: Gaohong Xu;Guohai Liu;Ming Chen;Xinxin Du;Meimei Xu;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Coverage and Rate Analysis for Facilitating Machine-to-Machine Communication in LTE-A Networks Using Device-to-Device Communication
Abstract:
With a wide range of applications, Machine-to-Machine (M2M) communication has become an emerging technology for connecting generic machines to the Internet. To ensure ubiquity in connections across all machines, it is necessary to have a standard infrastructure, such as 3GPP LTE-A network infrastructure, that facilitates such type of communications. However, owing to the huge scale ofquery id="Q1"> machines to be deployed in near future and the nature of data transactions, ensuring ubiquitous connections among all the machines will be difficult. Solutions that not only maintain connectivity but also route machine data in a cost effective manner are the need of the hour. In this context, it has been suggested that Device-to-Device (D2D) communication can play a very important role in expanding network coverage and routing the data between source-destination machine pairs. In this paper, we conduct a feasibility study to highlight the impact of multi-hop D2D communication in increasing the network coverage and average rate of a Machine Type Communication (MTC) device. We present a stochastic geometry based framework to analyze the coverage probability and average data rate of a three-hop M2M network deployed along with User Equipments (UEs) and conduct extensive simulations to study the system performance. Our simulation results show that the three-hop M2M network formed from out-of-range MTC devices and UEs can significantly improve the coverage and average rate of the entire network. Due to the mobility of users in the network, design of robust routing mechanisms in such a time evolving network becomes difficult. Hence, we suggest the use of space-time graph built from the predicted user locations to design a cost efficient multi-hop D2D topology that enables routing of MTC data to its destination.
Autors: Siba Narayan Swain;Rahul Thakur;Siva Ram Murthy Chebiyyam;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: Nov 2017, volume: 16, issue:11, pages: 3014 - 3027
Publisher: IEEE
 
» Cramér–Rao Lower Bound Derivation and Performance Analysis for Space-Based SAR GMTI
Abstract:
This paper derives the Cramér–Rao lower bound (CRLB) for a general multichannel spaceborne synthetic aperture radar system for ground moving-target indication and provides a theoretical analysis of across-track velocity estimation for RADARSAT-2 and a fictitious satellite. The signal model assumes a deterministic target signal in Gaussian clutter and noise. In estimation theory, the CRLB provides a lower bound on the achievable variance of any unbiased estimator. An estimator that achieves this bound is called efficient; however, there is no guarantee that an efficient estimator can be found. Nonetheless, the theoretical variance of the efficient estimator provides a good measure of the capability of the system and serves as a valuable system performance validation tool. Even if an efficient estimator cannot be found, for radar systems, the CRLB provides a necessary, but not sufficient design baseline for measurement parameters, such as the number of subapertures for transmit and receive, power levels, pulse-repetition frequency, and so on. CRLBs for a limited number of system configurations for RADARSAT-2 and TerraSAR-X are presented by Cerutti-Maori et al. and Ender et al.; however, the complete analytical form of CRLB for a general system, which can be readily applied to an arbitrary antenna switching configuration, has not been previously derived.
Autors: Mamoon Rashid;Richard M. Dansereau;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Nov 2017, volume: 55, issue:11, pages: 6031 - 6043
Publisher: IEEE
 
» Creation of an Internal Cladding in Sapphire Optical Fiber Using the $^{6}$ Li(n, $alpha)^{3}$ H Reaction
Abstract:
The focus of this work is to extend optical frequency domain reflectometry sensing to sapphire optical fiber, by creating a cladding in the fiber. A cladding was created by irradiating a sapphire optical fiber, which was surrounded by an annulus of Li-6 enriched lithium carbonate (Li2CO3) powder, in The Ohio State University Research Reactor. The 6Li(n, reaction created high energy alpha particles and tritons that irradiated the fiber simultaneously to a depth of 24 microns along the entire periphery of the sapphire fiber, thereby slightly reducing the index of refraction in the fiber’s periphery and creating a cladding within the fiber. Transmitted light intensity profiles show that the ion implanted cladding made the fiber’s intensity profile nearly single mode. The cladding survived to the highest temperature that was tested (1500 °C). The cladding made the fiber sufficiently single mode that the cladded sapphire fiber, when read out with an optical backscatter reflectometer, produced distributed temperature measurements along the entire length of the fiber.
Autors: Brandon Augustus Wilson;Thomas E. Blue;
Appeared in: IEEE Sensors Journal
Publication date: Nov 2017, volume: 17, issue:22, pages: 7433 - 7439
Publisher: IEEE
 
» Criterion for the Electrical Resonance Stability of Offshore Wind Power Plants Connected Through HVDC Links
Abstract:
Electrical resonances may compromise the stability of HVDC-connected offshore wind power plants (OWPPs). In particular, an offshore HVDC converter can reduce the damping of an OWPP at low-frequency series resonances, leading to the system instability. The interaction between offshore HVDC converter control and electrical resonances of offshore grids is analyzed in this paper. An impedance-based representation of an OWPP is used to analyze the effect that offshore converters have on the resonant frequency of the offshore grid and on system stability. The positive-net-damping criterion, originally proposed for subsynchronous analysis, has been adapted to determine the stability of the HVDC-connected OWPP. The reformulated criterion enables the net damping of the electrical series resonance to be evaluated and establishes a clear relationship between electrical resonances of the HVDC-connected OWPPs and stability. The criterion is theoretically justified, with analytical expressions for low-frequency series resonances being obtained and stability conditions defined based on the total damping of the OWPP. Examples are used to show the influence that HVDC converter control parameters and the OWPP configuration have on stability. A root locus analysis and time-domain simulations in PSCAD/EMTDC are presented to verify the stability conditions.
Autors: Marc Cheah-Mane;Luis Sainz;Jun Liang;Nick Jenkins;Carlos Ernesto Ugalde-Loo;
Appeared in: IEEE Transactions on Power Systems
Publication date: Nov 2017, volume: 32, issue:6, pages: 4579 - 4589
Publisher: IEEE
 
» Crop Biophysical Properties Estimation Based on LiDAR Full-Waveform Inversion Using the DART RTM
Abstract:
This paper presents the results of a three-dimensional (3-D) model inversion in order to demonstrate the potential of small footprint light detection and ranging (LiDAR) waveforms for estimating crop biophysical properties. For such, we consider the height, leaf area index (LAI), and ground spectral reflectance of two maize and wheat fields. Crop structure spatial variability that is observed per measured waveform is a source of inaccuracy for the inversion of LiDAR small footprint waveforms. For example, in the maize field, standard deviation is 0.16 m for height and 0.6 for LAI. To mitigate this issue, all measured waveforms are first classified into maize and wheat clusters. Then, biophysical properties are assessed per cluster using a look-up table of waveforms that are simulated by the discrete anisotropic radiative transfer model that works with the LiDAR configuration and realistic crop 3-D mock-ups with varied properties. Results were tested against in situ measurements. Crop height is very well estimated, with root-mean-square error (RMSE) and 0.04 m for maize and wheat, respectively. LAI estimate is also accurate (RMSE = 0.17) for maize except for wheat last growth stage (RMSE = 0.5), possibly due to the wheat low LAI value. Finally, the field spatial heterogeneity justifies the selection of many clusters to get accurate results.
Autors: Sahar Ben Hmida;Abdelaziz Kallel;Jean-Philippe Gastellu-Etchegorry;Jean-Louis Roujean;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Nov 2017, volume: 10, issue:11, pages: 4853 - 4868
Publisher: IEEE
 
» Cross-Convolutional-Layer Pooling for Image Recognition
Abstract:
Recent studies have shown that a Deep Convolutional Neural Network (DCNN) trained on a large image dataset can be used as a universal image descriptor and that doing so leads to impressive performance for a variety of image recognition tasks. Most of these studies adopt activations from a single DCNN layer, usually a fully-connected layer, as the image representation. In this paper, we proposed a novel way to extract image representations from two consecutive convolutional layers: one layer is used for local feature extraction and the other serves as guidance to pool the extracted features. By taking different viewpoints of convolutional layers, we further develop two schemes to realize this idea. The first directly uses convolutional layers from a DCNN. The second applies the pre-trained CNN on densely sampled image regions and treats the fully-connected activations of each image region as a convolutional layer's feature activations. We then train another convolutional layer on top of that as the pooling-guidance convolutional layer. By applying our method to three popular visual classification tasks, we find that our first scheme tends to perform better on applications which demand strong discrimination on lower-level visual patterns while the latter excels in cases that require discrimination on category-level patterns. Overall, the proposed method achieves superior performance over existing approaches for extracting image representations from a DCNN. In addition, we apply cross-layer pooling to the problem of image retrieval and propose schemes to reduce the computational cost. Experimental results suggest that the proposed method achieves promising results for the image retrieval task.
Autors: Lingqiao Liu;Chunhua Shen;Anton van den Hengel;
Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence
Publication date: Nov 2017, volume: 39, issue:11, pages: 2305 - 2313
Publisher: IEEE
 
» Cross-Polarization Amplitudes of Obliquely Orientated Buildings With Application to Urban Areas
Abstract:
Buildings that are rotated with respect to the sensor trajectory could be erroneously classified as vegetated areas in the Pauli basis, and subsequently in many decomposition theorems despite the considerable amount of work done to solve that issue. This misjudgement is linked to the high level of their cross-polarized contribution. Using electromagnetic simulation tools and image analysis, we study the value of these cross-polarization components. We show that forested areas and cities exhibit significantly different cross-polarization levels; indeed, the origin of these components is actually distinct. Based on that, to discriminate between the two environments, we introduce an extension to the Pauli basis where the cross polarization is split into two classes, one for rotated dihedrals and the other for random scatterers. This approach is then tested on two synthetic aperture radar images: the first acquired at C-band using RADARSAT-2 over Downtown San Francisco and the second using RAMSES at X-band over an industrial area near Paris.
Autors: R. Guinvarc’h;L. Thirion-Lefevre;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Nov 2017, volume: 14, issue:11, pages: 1913 - 1917
Publisher: IEEE
 
» Cross-Validated Variable Selection in Tree-Based Methods Improves Predictive Performance
Abstract:
Recursive partitioning methods producing tree-like models are a long standing staple of predictive modeling. However, a fundamental flaw in the partitioning (or splitting) rule of commonly used tree building methods precludes them from treating different types of variables equally. This most clearly manifests in these methods’ inability to properly utilize categorical variables with a large number of categories, which are ubiquitous in the new age of big data. We propose a framework to splitting using leave-one-out (LOO) cross validation (CV) for selecting the splitting variable, then performing a regular split (in our case, following CART's approach) for the selected variable. The most important consequence of our approach is that categorical variables with many categories can be safely used in tree building and are only chosen if they contribute to predictive power. We demonstrate in extensive simulation and real data analysis that our splitting approach significantly improves the performance of both single tree models and ensemble methods that utilize trees. Importantly, we design an algorithm for LOO splitting variable selection which under reasonable assumptions does not substantially increase the overall computational complexity compared to CART for two-class classification.
Autors: Amichai Painsky;Saharon Rosset;
Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence
Publication date: Nov 2017, volume: 39, issue:11, pages: 2142 - 2153
Publisher: IEEE
 
» Crowd-Based Ambient Assisted Living to Monitor the Elderly’s Health Outdoors
Abstract:
Ambient assisted living (AAL) technologies can help the elderly maintain their independence while keeping them safer. Sensors monitor their activities to detect situations in which they might need help. Most research in this area has targeted indoor environments, but outdoor activities are just as important; many risky situations might occur outdoors. SafeNeighborhood (SN) is an AAL system that combines data from multiple sources with collective intelligence to tune sensor data. It merges mobile, ambient, and AI technologies with old-fashioned neighborhood ties to create safe outdoor spaces. The initial results indicate SN’s potential use and point toward new opportunities for care of the elderly.
Autors: Ana Cristina Bicharra Garcia;Adriana Santarosa Vivacqua;Nayat Sánchez-Pi;Luis Martí;José M. Molina;
Appeared in: IEEE Software
Publication date: Nov 2017, volume: 34, issue:6, pages: 53 - 57
Publisher: IEEE
 
» Cryptanalysis of a Privacy-Preserving Aggregation Protocol
Abstract:
Privacy-preserving aggregation protocols allow an untrusted aggregator to evaluate certain statistics over a population of individuals without learning each individual’s privately owned data. In this note, we show that a recent protocol for computing an aggregate sum due to Jung, Li, and Wan (IEEE Transactions on Dependable and Secure Computing, 2015) is universally breakable, that is, anyone is able to recover each individual’s private data from the corresponding ciphertext. We also describe an alternate collusion attack against their companion product protocol.
Autors: Marc Joye;
Appeared in: IEEE Transactions on Dependable and Secure Computing
Publication date: Nov 2017, volume: 14, issue:6, pages: 693 - 694
Publisher: IEEE
 
» Crystal Orientation Dependence of Magnetization and Magnetostriction Behaviors in Highly Textured Galfenol and Alfenol Thin Sheets
Abstract:
Highly textured rolled sheets of Fe–Ga and Fe–Al alloys behave like single crystal, exhibiting magnetostriction values that are equal to ~ 80%–95% of those of single crystal along the axes. In this paper, we investigate the crystal orientation dependence of anisotropic magnetization and magnetostriction properties in highly textured disks of Fe–Ga and Fe–Al alloys. The highly textured samples are composed of a single (011) plane and small isolated grains, aside from the (011) grain, which exhibit three different cubic crystal orientations, such as , , and directions. Measured magnetostriction values strongly depend on a deviation angle of the direction from the rolling direction, well matched with the predicted values based on the anisotropic magnetostriction equation in the (011) plane. Of particular interest is the observation that measured values at the deviation angles over ~20° are higher than the predicted ones as much as the fraction of island grains with principal and directions along the strain measurement direction. In addition, it seems to be averaged out for magnetization behaviors along the three different direction- in comparison with those of the single crystal Fe–Ga.
Autors: Suok-Min Na;Joshua Eng-Morris;Julia Downing;Alison B. Flatau;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Crystallographic Orientation and Microstructure-Dependent Magnetic Behaviors in Arrays of Ni Nanowires
Abstract:
The magnetic behavior of a material is determined by its microstructure, or more precisely, by the configuration of electrons and their interactions with lattices. It has been difficult to control the microstructures of polycrystalline metallic nanowires through electrochemical deposition. Here, we report the synthesis, microstructure, and magnetic properties of nickel (Ni) nanowires from the viewpoints of crystallographic orientation and grain size. Changes in both the Ni precursor and buffer solution result in a remarkable modification of crystallographic orientation and magnetocrystalline anisotropy energy, and consequently, a difference in magnetic susceptibility is observed. In addition, a significant enlargement in grain size with a [220] texture is observed when raising the temperature during electrochemical deposition and subsequently brings a decrease in experimental coercivities.
Autors: Min Jun Ko;Su Hyo Kim;Young Keun Kim;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» CSI-Based Device-Free Wireless Localization and Activity Recognition Using Radio Image Features
Abstract:
Device-free wireless localization and activity recognition is an emerging technique, which could estimate the location and activity of a person without equipping him/her with any device. It deduces the state of a person by analyzing his/her influence on surrounding wireless signals. Therefore, how to characterize the influence of human behaviors is the key question. In this paper, we explore and exploit a radio image processing approach to better characterize the influence of human behaviors on Wi-Fi signals. Traditional methods deal with channel state information (CSI) measurements on each channel independently. However, CSI measurements on different channels are correlated, and thus lots of useful information involved with channel correlation may be lost. This motivates us to look on CSI measurements from multiple channels as a radio image and deal with it from the two-dimensional perspective. Specifically, we transform CSI measurements from multiple channels into a radio image, extract color and texture features from the radio image, adopt a deep learning network to learn optimized deep features from image features, and estimate the location and activity of a person using a machine learning approach. Benefits from the informative and discriminative deep image features and experimental results in two clutter laboratories confirm the excellent performance of the proposed system.
Autors: Qinhua Gao;Jie Wang;Xiaorui Ma;Xueyan Feng;Hongyu Wang;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Nov 2017, volume: 66, issue:11, pages: 10346 - 10356
Publisher: IEEE
 
» Current Harmonic Compensation for $n$ -Phase Machines With Asymmetrical Winding Arrangement and Different Neutral Configurations
Abstract:
Low-order current harmonics arise in ac drives due to nonlinearities, producing torque ripple and extra losses. In multiphase machines, which offer advantages over three-phase ones, the latter is aggravated because some harmonics map in low-impedance no-torque subspaces. A multiple-resonant-controller (MRC) structure, combining resonant controllers and synchronous frames, was proposed for harmonic cancellation. It permits substantial computational saving over the multiple-synchronous-frame (MSF) strategy, which includes proportional-integral control in one synchronous frame per harmonic. However, such MRC method is only suitable for symmetrical winding arrangements (SWAs), while asymmetrical winding arrangements (AWAs) are also widespread. Adapting the MRC for AWAs is not straightforward, since the harmonic mapping differs significantly from SWAs, and the effect of neutral configurations on it is more complicated and has hardly been studied. In this paper, an MRC strategy for multiphase machines with AWA is developed. Different neutral configurations are considered; particularly, it is shown and taken into account that for a single isolated neutral, unlike with SWAs, certain subspaces are coupled and unbalanced. The optimum frequencies of the resonant controllers and synchronous frames are assessed. The computational burden of the MRC and MSF schemes is compared, and the differences with SWAs are established. Experimental results are provided.
Autors: Alejandro G. Yepes;Jesús Doval-Gandoy;Fernando Baneira;Diego Pérez-Estévez;Oscar López;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Nov 2017, volume: 53, issue:6, pages: 5426 - 5439
Publisher: IEEE
 
» Current Reconstruction of Bundle Conductors Based on Tunneling Magnetoresistive Sensors
Abstract:
The current monitoring of bundle conductors is essential for precisely locating operation failures in transmission lines, leading to a more stable and reliable power grid. This paper proposed a novel method for current reconstruction of bundle conductors, utilizing tunneling magnetoresistive (TMR) sensors. Both the normal and abnormal situations are discussed. The optimal and sub-optimal measurement points for sensors were obtained for concise current measurement with only one uniaxial TMR sensor. The current in each bundle conductor was calculated separately based on the comprehensive algorithm. Validation experiment indicated the error of the measurement and calculation system was no more than 10%, proving the robustness and feasibility of the measurement system and the algorithm. The reconstruction process takes full advantages of TMR sensors and provides a promising solution for transmission line monitoring in power grid.
Autors: Gen Zhao;Jun Hu;Shuai Zhao;Zhongxu Wang;Shan X. Wang;Jinliang He;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Curvature Sensor Based on In-Fiber Mach–Zehnder Interferometer Inscribed With Femtosecond Laser
Abstract:
In this paper, an in-fiber Mach-Zehnder interferometer inscribed by femtosecond laser for curvature sensing has been designed and manufactured. Its operating principle consists of a secondary waveguide inscription working as a sensing arm. This waveguide has been manufactured using asymmetric structures with an average refractive index change of 1.1 × 10-2 in its guiding section measured by refracted near-field profilometry. The overall arm/cladding index difference is higher than its core/cladding counterpart, which is a suggested condition for device operation following preliminary simulations. The manufactured Mach-Zehnder interferometer exhibits a linear response to bending radius that is also dependent on an established bending axis. Sensitivity has been measured up to 9.49 nm/m-1 for curvature ranges from 0 to 14 m-1. Simulation results using the beam propagation method and conformal mapping transformation to convert bending action into a tilt refractive index agree with experimental results for the same index parameters. Preliminary temperature test shows a remarkable cross sensitivity of 0.0024(3) m-1/°C up to 180 °C.
Autors: David Pallarés-Aldeiturriaga;Luis Rodríguez-Cobo;Antonio Quintela;José M. López-Higuera;
Appeared in: Journal of Lightwave Technology
Publication date: Nov 2017, volume: 35, issue:21, pages: 4624 - 4628
Publisher: IEEE
 
» Curvature-Eliminating Head Field and Track Edge Characteristics in Heat-Assisted Magnetic Recording
Abstract:
Transition curvature in heat-assisted magnetic recording can be eliminated by appropriately varying head field amplitude across recording track width. In this paper, we present a systematic micromagnetic study on the effects of non-vanishing field beyond track edges in practical head designs, focusing on the recording characteristics beyond track edges. It is found that a uniform field amplitude beyond track edges will create wing-like patterns beyond straightened transitions, forming erase bands at high linear densities. The width of the erase band decreases if the head field diminishes beyond track edges. However, for practical field reduction gradients beyond track edges, the width of the erase band still remains significant.
Autors: Yuwei Qin;Hai Li;Jian-Gang Zhu;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Cutting Latency Tail: Analyzing and Validating Replication without Canceling
Abstract:
Response time variability in software applications can severely degrade the quality of the user experience. To reduce this variability, request replication emerges as an effective solution by spawning multiple copies of each request and using the result of the first one to complete. Most previous studies have mainly focused on the mean latency for systems implementing replica cancellation, i.e., all replicas of a request are canceled once the first one finishes. Instead, we develop models to obtain the response-time distribution for systems where replica cancellation may be too expensive or infeasible to implement, as in “fast” systems, such as web services, or in legacy systems. Furthermore, we introduce a novel service model to explicitly consider correlation in the processing times of the request replicas, and design an efficient algorithm to parameterize the model from real data. Extensive evaluations on a MATLAB benchmark and a three-tier web application (MediaWiki) show remarkable accuracy, e.g., 7 (4 percent) average error on the 99th percentile response time for the benchmark (respectively, MediaWiki), the requests of which execute in the order of seconds (respectively, milliseconds). Insights into optimal replication levels are thereby gained from this precise quantitative analysis, under a wide variety of system scenarios.
Autors: Zhan Qiu;Juan F. Pérez;Robert Birke;Lydia Chen;Peter G. Harrison;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Nov 2017, volume: 28, issue:11, pages: 3128 - 3141
Publisher: IEEE
 
» Cyber Threats Facing Autonomous and Connected Vehicles: Future Challenges
Abstract:
Vehicles are currently being developed and sold with increasing levels of connectivity and automation. As with all networked computing devices, increased connectivity often results in a heightened risk of a cyber security attack. Furthermore, increased automation exacerbates any risk by increasing the opportunities for the adversary to implement a successful attack. In this paper, a large volume of publicly accessible literature is reviewed and compartmentalized based on the vulnerabilities identified and mitigation techniques developed. This review highlighted that the majority of studies are reactive and vulnerabilities are often discovered by friendly adversaries (white-hat hackers). Many gaps in the knowledge base were identified. Priority should be given to address these knowledge gaps to minimize future cyber security risks in the connected and autonomous vehicle sector.
Autors: Simon Parkinson;Paul Ward;Kyle Wilson;Jonathan Miller;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: Nov 2017, volume: 18, issue:11, pages: 2898 - 2915
Publisher: IEEE
 
» Cyclic Scheduling of Multi-Cluster Tools Based on Mixed Integer Programming
Abstract:
Multi-cluster tools are automated equipment which is increasingly used in semiconductor manufacturing. The scheduling of multi-cluster tools is much more challenging than single-cluster tools due to multi-robot coordination and increasing chambers. In this paper, we develop a mixed integer programming (MIP) model which manages to formulate the multi-robot coordination for cyclic scheduling of multi-cluster tools. Three reformulations of the model are implemented: 1) linearization; 2) eliminating integer variables; and 3) tightening constraints. The first reformulation is designed to make the MIP model solvable by commercial solvers while the other two are intended for promoting computational efficiency which is critical when chambers increase. The proposed model can meet various practical scheduling requirements such as dual-armed robots, wafer residency time constraints, parallel and reentrant processes in multi-cluster tools. Experimental results demonstrate the efficiency of the proposed method.
Autors: Tianpeng Bao;Huangang Wang;
Appeared in: IEEE Transactions on Semiconductor Manufacturing
Publication date: Nov 2017, volume: 30, issue:4, pages: 515 - 525
Publisher: IEEE
 
» Damping Representation for the Fifth-Order Generator Model in Transient Behaviors
Abstract:
An expression of the compensation torque is derived to reduce the difference between the fifth-order generator model and the seventh-order model. It is appended to the swing equation in the fifth-order model, with the voltage equations and the flux linkage equations unchanged. Based on the singular perturbation theory, the stator transients are approximated. The fast current components of three rotor windings are represented by equivalent d- and q-axis stator current increments that create the same stator flux linkage. The relationship between this torque and damping is clarified from a physical viewpoint. Simulations on two systems show that the compensation torque reduces the model difference. The proposed damping preserving model overcomes the difficulty in determining the damping torque coefficient and is applicable to online transient stability analysis.
Autors: Ningqiang Jiang;Hsiao-Dong Chiang;
Appeared in: IEEE Transactions on Power Systems
Publication date: Nov 2017, volume: 32, issue:6, pages: 4924 - 4933
Publisher: IEEE
 
» Data Aggregation and Packet Bundling of Uplink Small Packets for Monitoring Applications in LTE
Abstract:
In cellular massive machine-type communications, a device can transmit directly to the BS or through an aggregator (intermediate node). While direct device-BS communication has recently been the focus of 5G/3GPP research and standardization efforts, the use of aggregators remains a less explored topic. In this article we analyze the deployment scenarios in which aggregators can perform cellular access on behalf of multiple MTC devices. We study the effect of packet bundling at the aggregator, which alleviates overhead and resource waste when sending small packets. The aggregators give rise to a trade-off between access congestion and resource starvation, and we show that packet bundling can minimize resource starvation, especially for smaller numbers of aggregators. Under the limitations of the considered model, we investigate the optimal settings of the network parameters in terms of number of aggregators and packet bundle size. Our results show that, in general, data aggregation can benefit the uplink massive MTC in LTE by reducing the signaling overhead.
Autors: Dong Min Kim;Rene Brandborg Sorensen;Kashif Mahmood;Olav Norvald Osterbo;Andrea Zanella;Petar Popovski;
Appeared in: IEEE Network
Publication date: Nov 2017, volume: 31, issue:6, pages: 32 - 38
Publisher: IEEE
 
» Data Glove System Embedded With Inertial Measurement Units for Hand Function Evaluation in Stroke Patients
Abstract:
This paper proposes a data glove system integrated with six-axis inertial measurement unit sensors for evaluating the hand function of patients who have suffered a stroke. The modular design of this data glove facilitates its use for stroke patients. The proposed system can use the hand’s accelerations, angular velocities, and joint angles as calculated by a quaternion algorithm, to help physicians gain new insights into rehabilitation treatments. A clinical experiment was performed on 15 healthy subjects and 15 stroke patients whose Brunnstrom stages (BSs) ranged from 4 to 6. In this experiment, the participants were subjected to a grip task, thumb task, and card turning task to produce raw data and three features, namely, the average rotation speed, variation of movement completion time, and quality of movement; these features were extracted from the recorded data to form 2-D and 3-D scatter plots. These scatter plots can provide reference information and guidance to physicians who must determine the BSs of stroke patients. The proposed system demonstrated a hit rate of 70.22% on average. Therefore, this system can effectively reduce physicians’ load and provide them with detailed information about hand function to help them adjust rehabilitation strategies for stroke patients.
Autors: Bor-Shing Lin;Pei-Chi Hsiao;Shu-Yu Yang;Che-Shih Su;I-Jung Lee;
Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Publication date: Nov 2017, volume: 25, issue:11, pages: 2204 - 2213
Publisher: IEEE
 
» Data Handling in EAST Remote Participation
Abstract:
International collaboration has become increasingly frequent in fusion research. It improves the quality and efficiency of the research in Experimental Advanced Superconducting Tokamak (EAST) facility. The traditional face-to-face collaborative way has been proven inadequate in current situation. The remote participation system (RPS) for EAST (EAST RPS) will play an important role in EAST operation experiment. Data handling for remote access through Internet are a critical issue for EAST RPS. There are three types of data in EAST RPS: engineer data, scientific raw data, and camera data. This paper presents the technical solutions for data handling in EAST RPS including the system architecture, data compression technologies, protocols, and a new experimental physics and industrial control system data archiving Engine.
Autors: Xiaoyang Sun;Feng Wang;Yong Wang;Shi Li;
Appeared in: IEEE Transactions on Nuclear Science
Publication date: Nov 2017, volume: 64, issue:11, pages: 2891 - 2894
Publisher: IEEE
 
» Data Rate Effects on Transition and Remanence Noise in a Modeled Heat-Assisted Magnetic Recording System
Abstract:
The heat-assisted magnetic recording performance at varying data rate conditions is investigated using an ensemble waveform analysis method. This method decouples the transition signal-to-noise ratio (SNR) and the remanence SNR from the total spatial media SNR. For data rates below 2200 Mbpsi, transition and remanence noises are largely independent of writer field rise time (RT) values less than 150 ps. Above a data rate of 2200 Mbpsi, the transition SNR is significantly degraded for the slowest RTs considered. For all data rate values, the remanence SNR sees minimal degradation with increasing RT. At the highest data rate, at least a 1 dB loss is observed compared with the lowest data rate, across the RT range considered. For comparison, spin-stand data were also collected. The modeled results were contrasted to bit error rate (BER) trends obtained from the measurement. The spin-stand data show a significant BER degradation as a function of increasing RT at higher data rates. This trend is likely explained with the increase in transition noise observed in the model. These results suggest that moderate writer field RTs do not degrade either transition or remanence noise significantly. If RTs can be kept low, higher data rates may be allowable from a media noise perspective.
Autors: Stephanie Hernández;Steven Granz;Pavol Krivosik;Pin-Wei Huang;Walt Eppler;Tim Rausch;Edward Gage;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Data Rate for Distributed Consensus of Multiagent Systems With High-Order Oscillator Dynamics
Abstract:
Distributed consensus under data rate constraint is an important research topic of multiagent systems. Some results have been obtained for consensus of multiagent systems with integrator dynamics, but it remains challenging for general high-order systems, especially in the presence of unmeasurable states. In this paper, we study the quantized consensus problem for a special kind of high-order critical systems and investigate the corresponding data rate required for achieving consensus. The state matrix of each agent is a th order real Jordan block admitting identical pairs of conjugate poles on the unit circle; each agent has a single input, and only the first state variable can be measured. The case of harmonic oscillators () is first investigated under a directed communication topology which contains a spanning tree, while the general case of is considered for a connected and undirected network. In both cases, the sufficient number of communication bits to guarantee the exponentially fast consensus is shown to be an integer between and , depending on the location of the poles.
Autors: Zhirong Qiu;Lihua Xie;Yiguang Hong;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Nov 2017, volume: 62, issue:11, pages: 6065 - 6072
Publisher: IEEE
 
» Decentralized Caching and Coded Delivery With Distinct Cache Capacities
Abstract:
Decentralized proactive caching and coded delivery is studied in a content delivery network, where each user is equipped with a cache memory, not necessarily of equal capacity. Cache memories are filled in advance during the off-peak traffic period in a decentralized manner, i.e., without the knowledge of the number of active users, their identities, or their particular demands. User demands are revealed during the peak traffic period, and are served simultaneously through an error-free shared link. The goal is to find the minimum delivery rate during the peak traffic period that is sufficient to satisfy all possible demand combinations. A group-based decentralized caching and coded delivery scheme is proposed, and it is shown to improve upon the state of the art in terms of the minimum required delivery rate when there are more users in the system than files. Numerical results indicate that the improvement is more significant as the cache capacities of the users become more skewed. A new lower bound on the delivery rate is also presented, which provides a tighter bound than the classical cut-set bound.
Autors: Mohammad Mohammadi Amiri;Qianqian Yang;Deniz Gündüz;
Appeared in: IEEE Transactions on Communications
Publication date: Nov 2017, volume: 65, issue:11, pages: 4657 - 4669
Publisher: IEEE
 
» Decentralized Frank–Wolfe Algorithm for Convex and Nonconvex Problems
Abstract:
Decentralized optimization algorithms have received much attention due to the recent advances in network information processing. However, conventional decentralized algorithms based on projected gradient descent are incapable of handling high-dimensional constrained problems, as the projection step becomes computationally prohibitive. To address this problem, this paper adopts a projection-free optimization approach, a.k.a. the Frank–Wolfe (FW) or conditional gradient algorithm. We first develop a decentralized FW (DeFW) algorithm from the classical FW algorithm. The convergence of the proposed algorithm is studied by viewing the decentralized algorithm as an inexact FW algorithm. Using a diminishing step size rule and letting be the iteration number, we show that the DeFW algorithm's convergence rate is for convex objectives; is for strongly convex objectives with the optimal solution in the interior of the constraint set; and is toward a stationary point for smooth but nonconvex objectives. We then show that a consensus-based DeFW algorithm meets the above guarantees with two communication rounds per iteration. We demonstrate the advantages of the proposed DeFW algorithm on low-complexity robust matrix completion and communication efficient sparse learning. Numerical results on synthetic and real data are presented to support our findings.
Autors: Hoi-To Wai;Jean Lafond;Anna Scaglione;Eric Moulines;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Nov 2017, volume: 62, issue:11, pages: 5522 - 5537
Publisher: IEEE
 
» Decentralized Prediction-Correction Methods for Networked Time-Varying Convex Optimization
Abstract:
We develop algorithms that find and track the optimal solution trajectory of time-varying convex optimization problems that consist of local and network-related objectives. The algorithms are derived from the prediction-correction methodology, which corresponds to a strategy where the time-varying problem is sampled at discrete time instances, and then, a sequence is generated via alternatively executing predictions on how the optimizers at the next time sample are changing and corrections on how they actually have changed. Prediction is based on how the optimality conditions evolve in time, while correction is based on a gradient or Newton method, leading to decentralized prediction-correction gradient and decentralized prediction-correction Newton. We extend these methods to cases where the knowledge on how the optimization programs are changing in time is only approximate and propose decentralized approximate prediction-correction gradient and decentralized approximate prediction-correction Newton. Convergence properties of all the proposed methods are studied and empirical performance is shown on an application of a resource allocation problem in a wireless network. We observe that the proposed methods outperform existing running algorithms by orders of magnitude. The numerical results showcase a tradeoff between convergence accuracy, sampling period, and network communications.
Autors: Andrea Simonetto;Alec Koppel;Aryan Mokhtari;Geert Leus;Alejandro Ribeiro;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Nov 2017, volume: 62, issue:11, pages: 5724 - 5738
Publisher: IEEE
 
» Decentralized State Estimation and Remedial Control Action for Minimum Wind Curtailment Using Distributed Computing Platform
Abstract:
Intermittency of wind energy poses a great challenge for power system operation and control. Wind curtailment might be necessary at the certain operating condition to keep the line flow within the limit. Remedial action scheme (RAS) offers quick control action mechanism to keep reliability and security of the power system operation with high wind energy integration. In this paper, a new RAS is developed to maximize the wind energy integration without compromising the security and reliability of the power system based on specific utility requirements. A new distributed linear state estimation (DLSE) is also developed to provide the fast and accurate input data for the proposed RAS. A distributed computational architecture is designed to guarantee the robustness of the cyber system to support RAS and DLSE implementation. The proposed RAS and DLSE is validated using the modified IEEE-118 Bus system. Simulation results demonstrate the satisfactory performance of the DLSE and the effectiveness of RAS. Real-time cyber-physical testbed has been utilized to validate the cyber resiliency of the developed RAS against computational node failure.
Autors: Ren Liu;Anurag K. Srivastava;David E. Bakken;Alexander Askerman;Patrick Panciatici;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Nov 2017, volume: 53, issue:6, pages: 5915 - 5926
Publisher: IEEE
 
» Decoding Kinematics Using Task-Independent Movement-Phase-Specific Encoding Models
Abstract:
Neural decoders of kinematic variables have largely relied on task-dependent (TD) encoding models of the neural activity. TD decoders, though, require prior knowledge of the tasks, which may be unavailable, lack scalability as the number of tasks grows, and require a large number of trials per task to reduce the effects of neuronal variability. The execution of movements involves a sequence of phases (e.g., idle, planning, and so on) whose progression contributes to the neuronal variability. We hypothesize that information about the movement phase facilitates the decoding of kinematics and compensates for the lack of prior knowledge about the task. We test this hypothesis by designing a task-independent movement-phase-specific (TI-MPS) decoding algorithm. The algorithm assumes that movements proceed through a consistent sequence of phases regardless of the specific task, and it builds one model per phase by combining data from different tasks. Phase transitions are detected online from neural data and, for each phase, a specific encoding model is used. The TI-MPS algorithm was tested on single-unit recordings from 437 neurons in the dorsal and ventral pre-motor cortices from two nonhuman primates performing 3-D multi-object reach-to-grasp tasks. The TI-MPS decoder accurately decoded kinematics from tasks it was not trained for and outperformed TD approaches (one-way ANOVA with Tukey’s post-hoc test and -value <0.05). Results indicate that a TI paradigm with MPS models may help decoding kinematics when prior information about the task is unavailable and pave the way toward clinically viable prosthetics.
Autors: Stefan L. Sumsky;Marc H. Schieber;Nitish V. Thakor;Sridevi V. Sarma;Sabato Santaniello;
Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Publication date: Nov 2017, volume: 25, issue:11, pages: 2122 - 2132
Publisher: IEEE
 
» Decomposition of Multi-Channel Intramuscular EMG Signals by Cyclostationary-Based Blind Source Separation
Abstract:
We propose a novel decomposition method for electromyographic signals based on blind source separation. Using the cyclostationary properties of motor unit action potential trains (MUAPt), it is shown that the MUAPt can be decomposed by joint diagonalization of the cyclic spatial correlation matrix of the observations. After modeling the source signals, we provide the proof of orthogonality of the sources and of their delayed versions in a cyclostationary context. We tested the proposed method on simulated signals and showed that it can decompose up to six sources with a probability of correct detection and classification >95%, using only eight recording sites. Moreover, we tested the method on experimental multi-channel signals recorded with thin-film intramuscular electrodes, with a total of 32 recording sites. The rate of agreement of the decomposed MUAPt with those obtained by an expert using a validated tool for decomposition was >93%.
Autors: Julien Roussel;Philippe Ravier;Michel Haritopoulos;Dario Farina;Olivier Buttelli;
Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Publication date: Nov 2017, volume: 25, issue:11, pages: 2035 - 2045
Publisher: IEEE
 
» Deep CNNs With Spatially Weighted Pooling for Fine-Grained Car Recognition
Abstract:
Fine-grained car recognition aims to recognize the category information of a car, such as car make, car model, or even the year of manufacture. A number of recent studies have shown that a deep convolutional neural network (DCNN) trained on a large-scale data set can achieve impressive results at a range of generic object classification tasks. In this paper, we propose a spatially weighted pooling (SWP) strategy, which considerably improves the robustness and effectiveness of the feature representation of most dominant DCNNs. More specifically, the SWP is a novel pooling layer, which contains a predefined number of spatially weighted masks or pooling channels. The SWP pools the extracted features of DCNNs with the guidance of its learnt masks, which measures the importance of the spatial units in terms of discriminative power. As the existing methods that apply uniform grid pooling on the convolutional feature maps of DCNNs, the proposed method can extract the convolutional features and generate the pooling channels from a single DCNN. Thus minimal modification is needed in terms of implementation. Moreover, the parameters of the SWP layer can be learned in the end-to-end training process of the DCNN. By applying our method to several fine-grained car recognition data sets, we demonstrate that the proposed method can achieve better performance than recent approaches in the literature. We advance the state-of-the-art results by improving the accuracy from 92.6% to 93.1% on the Stanford Cars-196 data set and 91.2% to 97.6% on the recent CompCars data set. We have also tested the proposed method on two additional large-scale data sets with impressive results observed.
Autors: Qichang Hu;Huibing Wang;Teng Li;Chunhua Shen;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: Nov 2017, volume: 18, issue:11, pages: 3147 - 3156
Publisher: IEEE
 
» Deep Convolutional Neural Models for Picture-Quality Prediction: Challenges and Solutions to Data-Driven Image Quality Assessment
Abstract:
Convolutional neural networks (CNNs) have been shown to deliver standout performance on a wide variety of visual information processing applications. However, this rapidly developing technology has only recently been applied with systematic energy to the problem of picture-quality prediction, primarily because of limitations imposed by a lack of adequate ground-truth human subjective data. This situation has begun to change with the development of promising data-gathering methods that are driving new approaches to deep-learning-based perceptual picture-quality prediction. Here, we assay progress in this rapidly evolving field, focusing, in particular, on new ways to collect large quantities of ground-truth data and on recent CNN-based picture-quality prediction models that deliver excellent results in a large, real-world, picture-quality database.
Autors: Jongyoo Kim;Hui Zeng;Deepti Ghadiyaram;Sanghoon Lee;Lei Zhang;Alan C. Bovik;
Appeared in: IEEE Signal Processing Magazine
Publication date: Nov 2017, volume: 34, issue:6, pages: 130 - 141
Publisher: IEEE
 
» Deep Learning for Image-to-Text Generation: A Technical Overview
Abstract:
Generating a natural language description from an image is an emerging interdisciplinary problem at the intersection of computer vision, natural language processing, and artificial intelligence (AI). This task, often referred to as image or visual captioning, forms the technical foundation of many important applications, such as semantic visual search, visual intelligence in chatting robots, photo and video sharing in social media, and aid for visually impaired people to perceive surrounding visual content. Thanks to the recent advances in deep learning, the AI research community has witnessed tremendous progress in visual captioning in recent years. In this article, we will first summarize this exciting emerging visual captioning area. We will then analyze the key development and the major progress the community has made, their impact in both research and industry deployment, and what lies ahead in future breakthroughs.
Autors: Xiaodong He;Li Deng;
Appeared in: IEEE Signal Processing Magazine
Publication date: Nov 2017, volume: 34, issue:6, pages: 109 - 116
Publisher: IEEE
 
» Deep Learning for Visual Understanding [From the Guest Editors]
Abstract:
Autors: Fatih Porikli;Shiguang Shan;Cees Snoek;Rahul Sukthankar;Xiaogang Wang;
Appeared in: IEEE Signal Processing Magazine
Publication date: Nov 2017, volume: 34, issue:6, pages: 24 - 25
Publisher: IEEE
 

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