Electrical and Electronics Engineering publications abstract of: 11-2017 sorted by title, page: 17

» Stray gassing of transformer insulating oils: impact of materials, oxygen content, additives, incubation time and temperature, and its relationship to oxidation stability
Abstract:
For many years, dissolved gas analysis (DGA) has been considered worldwide as the most important technique for evaluating the state of health of oil-filled power transformers. Based on regular analysis and trending of the dissolved gases extracted from insulating oil samples, an assessment can be made whether internal transformer abnormalities are present and how critical these abnormalities are [1], [2].
Autors: Steve Eeckhoudt;Stijn Autru;Luc Lerat;
Appeared in: IEEE Electrical Insulation Magazine
Publication date: Nov 2017, volume: 33, issue:6, pages: 27 - 32
Publisher: IEEE
 
» StreaMon: A Data-Plane Programming Abstraction for Software-Defined Stream Monitoring
Abstract:
The fast evolving nature of modern cyber threats and network monitoring needs calls for new, “software-defined”, approaches to simplify and quicken programming and deployment of online (stream-based) traffic analysis functions. StreaMon is a carefully designed data-plane abstraction devised to scalably decouple the “programming logic” of a traffic analysis application (tracked states, features, anomaly conditions, etc.) from elementary primitives (counting and metering, matching, events generation, etc), efficiently pre-implemented in the probes, and used as common instruction set for supporting the desired logic. Multi-stage multi-step real-time tracking and detection algorithms are supported via the ability to deploy custom states, relevant state transitions, and associated monitoring actions and triggering conditions. Such a separation entails platform-independent, portable, online traffic analysis tasks written in a high level language, without requiring developers to access the monitoring device internals and program their custom monitoring logic via low level compiled languages (e.g., C, assembly, VHDL). We validate our design by developing a prototype and a set of simple (but functionally demanding) use-case applications and by testing them over real traffic traces.
Autors: Marco Bonola;Giuseppe Bianchi;Giulio Picierro;Salvatore Pontarelli;Marco Monaci;
Appeared in: IEEE Transactions on Dependable and Secure Computing
Publication date: Nov 2017, volume: 14, issue:6, pages: 664 - 678
Publisher: IEEE
 
» Strong Dynamic Interactions of Grid-Connected DFIGs With Power Systems Caused by Modal Coupling
Abstract:
This paper establishes a closed-loop interconnected dynamic model of a power system with a doubly fed induction generator (DFIG) for wind power generation, wherein, the DFIG and power system are modeled as two open-loop interconnected subsystems. The established model indicates that the impact of the dynamic interactions introduced by the DFIG on the power system's small-signal angular stability is the difference between the closed-loop and open-loop electromechanical oscillation modes (EOMs). The analysis conducted in this study reveals that when an open-loop DFIG oscillation mode (DOM) is close to an open-loop EOM on the complex plane, the modal coupling of the open-loop EOM and DOM can cause strong dynamic interactions between the DFIG and the power system; thus, the DFIG has a significant impact on the power system's small-signal angular stability. An example multimachine power system with grid-connected DFIGs is presented to demonstrate and validate the analysis and conclusions made in the paper.
Autors: Wenjuan Du;Xiao Chen;H. F. Wang;
Appeared in: IEEE Transactions on Power Systems
Publication date: Nov 2017, volume: 32, issue:6, pages: 4386 - 4397
Publisher: IEEE
 
» Structural and Ferromagnetic Properties of Sputtered FeCoB/AlN Soft Magnetic Multilayers for GHz Applications
Abstract:
Owing to their large saturation magnetization and low hysteresis loss, soft magnetic layers based on amorphous alloys currently receive great attention for their potential for gigahertz frequencies applications. In this paper, we studied the structural and magnetic properties of amorphous FeCoB/AlN multilayered thin films with in-plane uniaxial magnetic anisotropy based on the Fe-28%Co-20%B (at. %) alloy, deposited on 8” Si/200 nm-thermal-SiO2 wafers in an industrial, high-throughput magnetron sputtering system. Depending on the process conditions and hardware configuration, the multilayers exhibit structural anisotropy consisting of surface ripples elongated perpendicular to the incident flux direction, which replicate through the entire multilayer stack. By varying the AlN interlayer thickness and sputter process parameters the anisotropy field of these films was tuned in the range of 25–130 Oe, while the coercivity along the magnetic easy axis was kept low, 0.2–0.3 Oe. The ferromagnetic resonance frequency of the multilayered structures was ~2 GHz, and the experimental behavior of the magnetization dynamics was described by the classical Landau–Lifschitz–Gilbert model. Magnetic domain imaging confirmed a strong coupling between the adjacent FeCoB layers, in agreement with the edge-curling wall model.
Autors: Claudiu Valentin Falub;Rachid Hida;Mojmír Meduňa;Josef Zweck;Jean-Philippe Michel;Henri Sibuet;Daniel Schneider;Martin Bless;Jan H. Richter;Hartmut Rohrmann;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 6
Publisher: IEEE
 
» Structural and Magnetic Properties in Mn2VAl Full-Heusler Epitaxial Thin Films
Abstract:
Epitaxially grown Mn2VAl full-Heusler thin films were fabricated on single crystalline MgO (001) substrates by using an ultra-high-vacuum magnetron sputtering technique. X-ray diffraction revealed that epitaxial Mn2VAl films with a highly -ordered structure were obtained by annealing around 600 °C. For the films deposited without a buffer layer and annealed at 500 °C–600 °C, the saturation magnetization was about 240 emu/cm3 at 300 K, which was close to the theoretical value. The effective magnetic damping constant of Mn2VAl thin films was investigated using the ferromagnetic resonance technique. The effective damping constant was much larger than expected due to the inhomogeneity in the Mn2VAl films.
Autors: Kenji Fukuda;Mikihiko Oogane;Yasuo Ando;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Structure, Magnetic, and Electrical Properties of La2NiO $_{4+delta }$ Compounds
Abstract:
We have investigated the structure, magnetic, and electrical properties, and the resistance switching effect (RSE) of La2NiO compounds with different excess oxygen levels of . Our results showed the structure changes from tetragonal I4/mmm to orthorhombic Fmmm when reducing value from 0.011 to 0.006. The curves measured at several temperatures exhibit a coexistence of the weak ferromagnetic and antiferromagnetic interactions. Two shoulders on curves related to the spin and charge ordering have also been observed. These ordering temperatures depend strongly on value and they shift toward lower temperature with decreasing . All the samples exhibit a semiconductor behavior and their temperature dependences of the resistivity obey the variable-range-hoping model. Interestingly, the typical current–voltage characteristics of the samples show a hysteresis, which suggests an existence of the RSE. We have observed two different states of the resistance corresponding to high () and low () values. The resistance change ratio of the samples defined as 100% is found to be about 18�- 25;–57%, which depends on the value of in the samples.
Autors: Tran Dang Thanh;H. T. Van;D. T. A. Thu;L. V. Bau;Nguyen Van Dang;D. N. H. Nam;L. V. Hong;Seong-Cho Yu;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Structure-Exploiting Delay-Dependent Stability Analysis Applied to Power System Load Frequency Control
Abstract:
Linear matrix inequality (LMI) based delay-dependent stability analysis/synthesis methods have been applied to power system load frequency control (LFC) which has communication networks in its loops. However, the computational burden of solving large-scale LMIs poses a great challenge to the application of those methods to real-world power systems. This paper investigates the computational aspect of delay-dependent stability analysis (DDSA) of LFC. The basic idea is to improve the numerical tractability of DDSA by exploiting the chordal sparsity and symmetry of the graph related to LFC loops. The graph-theoretic analysis yields the structure restrictions of weighting matrices needed for the LMIs to inherit the chordal sparsity of the control loops. By enforcing those structure restrictions on weighting matrices, the positive semidefinite constraints in the LMIs can be decomposed into smaller ones, and the number of decision variables can be greatly reduced. Symmetry in LFC control loops is also exploited to reduce the number of decision variables. Numerical studies show the proposed structure-exploiting techniques significantly improves the numerical tractability of DDSA at the cost of the introduction of acceptable minor conservatism.
Autors: Chao Duan;Chuan-Ke Zhang;Lin Jiang;Wanliang Fang;Wei Yao;
Appeared in: IEEE Transactions on Power Systems
Publication date: Nov 2017, volume: 32, issue:6, pages: 4528 - 4540
Publisher: IEEE
 
» Structure-Property Correlations of Carbon and Nitrogen Incorporated NiFe2O4
Abstract:
In this paper, carbon (C) and nitrogen (N) were incorporated into the interstitial sites of nickel (Ni) ferrite lattice. Structural studies of the incorporated NiFe2O4 (NFO) samples (C-NFO and N-NFO) using X-ray diffraction revealed changes in the values of the lattice parameter, bond angle, and bond length. Raman spectroscopic studies revealed shifts in peak positions of and (3) vibrational modes of the spectra. Magnetization measurements at 20 and 300 K using vibrating sample magnetometer showed decrease in the values of upon incorporation of C/N (/f.u. of C-NFO and /f.u. of N-NFO from /f.u. of NFO, at 20 K). An increase in intrinsic coercive field () value (18.2 Oe of C-NFO and 14.2 Oe of N-NFO from 5.2 Oe of NFO, at 20 K) was also observed. However, a reduction in the value of first-order cubic magnetocrystalline anisotropy constant () was observed upon incorporation of C/N. Microstructural analysis using scanning electron microscopic images revealed modifications in the shape and the size of the grains. The average grain size was found to be reduced upon C/N incorporation (~600 nm of NFO, while ~550 nm of C-NFO and ~400 nm of N-NFO).
Autors: K. B. Anoop Baby;Lijin George;Manu Jaiswal;G. Markandeyulu;A. Subrahmanyam;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Structured Projection-Based Model Reduction With Application to Stochastic Biochemical Networks
Abstract:
The chemical master equation (CME) is well known to provide the highest resolution models of a biochemical reaction network. Unfortunately, even simulating the CME can be a challenging task. For this reason, simpler approximations to the CME have been proposed. In this paper, we focus on one such model, the linear noise approximation (LNA). Specifically, we consider implications of a recently proposed LNA time-scale separation method. We show that the reduced-order LNA converges to the full-order model in the mean square sense. Using this as motivation, we derive a network structure-preserving reduction algorithm based on structured projections. We discuss when these structured projections exist and we present convex optimization algorithms that describe how such projections can be computed. The algorithms are then applied to a linearized stochastic LNA model of the yeast glycolysis pathway.
Autors: Aivar Sootla;James Anderson;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Nov 2017, volume: 62, issue:11, pages: 5554 - 5566
Publisher: IEEE
 
» Students’ Task Interpretation and Conceptual Understanding in an Electronics Laboratory
Abstract:
Task interpretation is a critical first step for students in the process of self-regulated learning, and a key determinant when they set goals in their learning and select strategies in assigned work. This paper focuses on the explicit and implicit aspects of task interpretation based on Hadwin’s model. Laboratory activities improve students’ conceptual understanding, as they utilize cognitive ability to integrate the new experiences these provide. The purpose of this paper is to investigate how students’ interpretation of a task assigned during laboratory work may change during the task process, and how this relates to their conceptual understanding. A total of 143 students enrolled in an electronics course participated in this paper. Instruments to measure task interpretation and conceptual understanding were created, piloted, and applied before and after selected laboratory activities over the semester. Findings suggest that while students’ task interpretation changes during the task process, increasing after the completion of the laboratory activity levels of task interpretation are low. Previous research findings—that students generally have an incomplete understanding of the assigned tasks and struggle to establish a connection between laboratory activities and the theory—were confirmed. Lastly, this paper reports a significant relationship between students’ task interpretation and their conceptual understanding in laboratory work. Further investigation is necessary to unveil other factors related to these constructs in order to engage students in laboratory work.
Autors: Presentacion Rivera-Reyes;Oenardi Lawanto;Michael L. Pate;
Appeared in: IEEE Transactions on Education
Publication date: Nov 2017, volume: 60, issue:4, pages: 265 - 272
Publisher: IEEE
 
» Study for Phosphorus Contamination to High Voltage Transistors
Abstract:
Threshold voltage () needs to be well controlled to determine the switching point of the transistors. However, variation was observed on high voltage transistor during development phase. Investigations show that the variation was caused by phosphorus contamination from wafer backside. Various wet chemical cleaning methods were evaluated to understand the effectiveness for the phosphorus decontamination. Good result was achieved with improved cleaning solution.
Autors: Liang Li;Qiong Luo;Zeng Yuan Wu;Yun Ling Tan;Alex See;Soo Cheng Chua;Troy Zhu;Chor Shu Cheng;
Appeared in: IEEE Transactions on Semiconductor Manufacturing
Publication date: Nov 2017, volume: 30, issue:4, pages: 323 - 327
Publisher: IEEE
 
» Study of Electronic Switching Between Multiple Backward-Wave Modes in a W-Band Extended Interaction Oscillator
Abstract:
The performance of electronic switching between multiple backward-wave modes is studied in a designed extended interaction oscillator (EIO) based on a ladder circuit with finite number of periods to overcome electronic tuning range limits of EIOs operated in standing-wave mode. The dispersion characteristic of the circuit with finite number of periods, which is constructed by a series of discrete modes, is investigated. The mode separation is analyzed and reduced to support continuous switching between multiple different modes by increasing the number of periods as compared with the standing-wave EIO approach. An output circuit is designed to extract the power of backward wave. The electronic switching between nine backward-wave modes has been achieved by changing the beam voltage from 4.1 to 10.5 kV, where the maximum output power over 58 W is obtained at 5.3 kV from the simulation prediction. The EIO can operate over an electronic tuning range of 3.53 GHz from 89.65 to 93.18 GHz in ensuring the output power no less than 20 W. This technique can be extensively applied to increase operating band for extended interaction klystrons (EIKs) and electronic tuning range for EIOs, making them more suitable for many potential applications.
Autors: Liangjie Bi;Yong Yin;Changpeng Xu;Zhang Zhang;Zhiwei Chang;Fanbo Zeng;Ruibin Peng;Wen Zhou;Abdur Rauf;Safi Ullah;Bing Wang;Hailong Li;Lin Meng;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Nov 2017, volume: 64, issue:11, pages: 4686 - 4692
Publisher: IEEE
 
» Study of the Effect of Annealing on the Properties of Mn2RuxGa Thin Films
Abstract:
The effect of vacuum annealing thin films of the compensated ferrimagnetic half-metal Mn2RuxGa at temperatures from 250 °C to 400 °C is investigated. The 39.3 nm films deposited on (100) MgO substrates exhibit perpendicular magnetic anisotropy due to a small ~ 1% tetragonal elongation induced by the substrate strain. The main change on annealing is a modification in the compensation temperature , which first increases from 50 K for the as-deposited film to 185 K after annealing at 250 °C, and then falls to 140 K after annealing at 400 °C. There are minor changes in the atomic order, coercivity, resistivity, and anomalous Hall effect (AHE), but the net magnetization measured by SQUID magnetometry with the field applied in-plane or perpendicular-to-the-plane changes more significantly. It saturates at 20 –30 kA at room temperature, and a small soft component is seen in the perpendicular SQUID loops, which is absent in the square AHE hysteresis loops. This is explained by the half-metallic nature of the compound; the AHE probes only the 4c Mn sublattice that provides the spin-polarized electrons at the Fermi level, whereas the SQUID measures the sum of the oppositely aligned 4c and 4a sublattice magnetizations.
Autors: K. E. Siewierska;G. Atcheson;K. Borisov;M. Venkatesan;K. Rode;J. M. D. Coey;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Study on Electromagnetic Force Characteristics Acting on Levitation/Guidance Coils of a Superconducting Maglev Vehicle System
Abstract:
Superconducting Maglev has been developed as a high-speed transport system. Superconducting coils (SC coils) are installed on the vehicle, and levitation/guidance coils (LG coils) are installed on the ground. A null-flux-type electrodynamic suspension system provided by electromagnetic interaction between SC coils and LG coils serves as the levitation and guidance functions of the vehicle system. Electromagnetic forces acting on SC coils are related to levitation and guidance functions of the vehicle. These forces were studied in previous research, and characteristics of levitation and guidance forces were revealed with respect to parameters of the design of the vehicle. On the other hand, electromagnetic forces acting on LG coils also exist as action–reaction pairs with the forces acting on SC coils. The forces act on LG coils in every levitated run of the vehicle, and stress is applied on the conductor and molded resin of the LG coils. In conventional studies, the vehicle design has been decided mainly by the electromagnetic forces acting on SC coils, and not by the forces acting on LG coils. The aim of the study is to establish an improved method to design the vehicle system with the objective of not only optimization of characteristics of the vehicle, but also consideration of stress on LG coils. As a preliminary study to establish the improved method, a study by computer simulation on characteristics of electromagnetic forces acting on LG coils with respect to the parameters of the vehicle is described in this paper.
Autors: Takenori Yonezu;Ken Watanabe;Erimitsu Suzuki;Takashi Sasakawa;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Study on Pattern Distortion and DOA Estimation Performance of Crossed-Loop/Monopole Antenna in HF Radar
Abstract:
Crossed-loop (CL)/monopole antenna has been widely used in high-frequency ground-wave radar for ocean surface remote sensing owing to its compact size. The multiple signal classification (MUSIC) algorithm is commonly adapted to achieve a favorable angular resolution for this broad beam antenna. However, the direction of arrival (DOA) estimation is always troubled by the frequently occurring distortion of antenna pattern. Previous studies are mainly focused on the calibration by using the actual pattern or other assistant algorithms. In this paper, theoretical analysis is made to illustrate the reason for pattern distortion, which draws a conclusion that the distortion is essentially due to the different influence of environmental obstacles upon the electric field part and magnetic field part. This also implies that there is nearly no distortion between the two loops, which is validated by three different experiments. Based on this conclusion, the DOA estimation performance of the MUSIC algorithm is studied by creating a numerical relationship associating the estimation error with distortion level. Furthermore, a new method using ideal pattern is proposed to improve the estimation performance by removing the amplitude information of monopole and relying on the CL processing. Both simulation and experimental results are given to prove its validity.
Autors: Yingwei Tian;Biyang Wen;Jian Tan;Ziyan Li;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Nov 2017, volume: 65, issue:11, pages: 6095 - 6106
Publisher: IEEE
 
» Study on Requirements for Load Emulation of the Vehicle With an Electric Braking System
Abstract:
For different configurations of the electric braking systems (EBS) in the vehicle, requirements for the emulation of their dynamic load on the test bench are studied in this paper, in order to determine appropriate parameters of the test equipment. First, models of three kinds of EBS as well as the test bench are built and characteristics of the transmission system including elasticity and backlash nonlinearity with their influences on the braking performance are fully considered. Two normal braking strategies, namely the maximum-motor-torque strategy and the good-pedal-feel strategy, are designed and the antilock braking strategy that includes the regenerative and friction blended torque control of the wheel slip ratio, the sliding mode control of the backlash, and the PID closed-loop control for elasticity compensation in the emergency condition is proposed. With these methods, motor and frictional braking torque are under the coordinated control to make the most of the EBS. Then, the scheme and control methods of load emulation including the PI method and the feedforward method on the test bench are put forward. Based on the models and control methods, vehicle braking results that indicate the emulation effects and requirements of different kinds of EBS in the MATLAB/Simulink environment are shown; and meanwhile, the dynamic performance parameters of the test bench containing the moment of inertia and the time constant of torque response are obtained for the selection of the test equipment. Finally, experiments on the real bench are carried out. The loading and motion of the vehicle EBS under various braking conditions can be accurately emulated on the proposed test bench and the reliable test results make it possible to investigate the EBS safely, economically, and time-efficiently in the laboratory.
Autors: Zhongshi Zhang;Lifang Wang;Junzhi Zhang;Ruihai Ma;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Nov 2017, volume: 66, issue:11, pages: 9638 - 9653
Publisher: IEEE
 
» Study on the Heat Transfer of GaN-Based High Power HEMTs
Abstract:
In this paper, study on the heat transfer of GaN-based high electron mobility transistors (HEMTs) on SiC substrate was carried out utilizing transient thermal analysis method. Gate-source voltage () is used as the temperature sensitive parameter. Linear relationship ( factor) between and temperature is obtained. It is found that the factor is proportional with drain-source current and does not change with the variation of drain-gate voltage in the linear region of HEMT. We proposed and proved that the factor should be calibrated with HEMT working at linear region to insure the accuracy of subsequent thermal evaluation. Moreover, the temperature rise and thermal resistance keeps as constant when factors were calibrated within the linear region. Transient thermal measurement turns out to be a non-destructive, fast, and precise method for the thermal performance analysis and quality control of the power HEMTs.
Autors: Lianqiao Yang;Zhangfu Chen;Xiaoxue Xu;Jianhua Zhang;
Appeared in: IEEE Transactions on Semiconductor Manufacturing
Publication date: Nov 2017, volume: 30, issue:4, pages: 526 - 530
Publisher: IEEE
 
» Studying the Reliability Implications of Line Switching Operations
Abstract:
This paper proposes a method for studying the reliability implications of line switching operations in power systems. Two case studies are conducted on RTS and IEEE 118-bus system to illustrate this method. This method is designed to explore previously overlooked areas in reliability evaluation of line switching operations. Line removal test is proposed to obtain simulation data of the system, and then with risk analysis and impact analysis, six reliability indices are used to evaluate reliability performance of each transmission line in the system. Instead of the traditionally used mean value, this method introduces variance into analysis. Weibull distribution is used to reconstruct distributions of reliability indices which provide worst case scenario comparisons in reliability evaluation. Eventually, with results obtained from the proposed reliability evaluation method, categorization for line switching operations is introduced to classify all transmission lines based on their reliability performance. The categories provide reliability implications of line switching operations and can be used for guidance in actual operations.
Autors: Shijia Zhao;Chanan Singh;
Appeared in: IEEE Transactions on Power Systems
Publication date: Nov 2017, volume: 32, issue:6, pages: 4614 - 4625
Publisher: IEEE
 
» Sub-Nyquist SAR via Fourier Domain Range-Doppler Processing
Abstract:
Conventional synthetic aperture radar (SAR) systems are limited in their ability to satisfy the increasing requirement for improved spatial resolution and wider coverage. The demand for high resolution requires high sampling rates, while coverage is limited by the pulse repetition frequency. Consequently, sampling rate reduction is of high practical value in SAR imaging. In this paper, we introduce a new algorithm, equivalent to the well-known range-Doppler method, to process SAR data using the Fourier series coefficients of the raw signals. We then demonstrate how to exploit the algorithm features to reduce sampling rate in both range and azimuth axes and process the signals at sub-Nyquist rates, by using compressive sensing (CS) tools. In particular, we demonstrate recovery of an image using only a portion of the received signal’s bandwidth and also while dropping a large percentage of the transmitted pulses. The complementary pulses may be used to capture other scenes within the same coherent processing interval. In addition, we propose exploiting the ability to reconstruct the image from narrow bands in order to dynamically adapt the transmitted waveform energy to vacant spectral bands, paving the way to cognitive SAR. The proposed recovery algorithms form a new CS-SAR imaging method that can be applied to high-resolution SAR data acquired at sub-Nyquist rates in range and azimuth. The performance of our method is assessed using simulated and real data sets. Finally, our approach is implemented in hardware using a previously suggested Xampling radar prototype.
Autors: Kfir Aberman;Yonina C. Eldar;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Nov 2017, volume: 55, issue:11, pages: 6228 - 6244
Publisher: IEEE
 
» Sub/Supraliminal Stimulus With Pseudo-“Blindsight” Under Exposure to Extremely Low-Frequency Fields
Abstract:
This paper was conducted to examine whether subliminal/supraliminal stimulus with phosphene as pseudo-blindsight under exposure to extremely low-frequency magnetic fields can control retinal activities through changes in the receptivity of the flicker sensation. Eight healthy male subjects ranging in age from 21 to 66 participated in the visual stimulus experiments. For the measurement on the effects of subliminal stimuli, we investigated the threshold variations after the pre-stimuli at 80% of the threshold at 20 Hz. The subliminal stimuli for 30 s and 45 s reduced the standard threshold value (9.8 mT) of the following phosphene by about 3.9% and 8.9%, respectively. In evaluating the supraliminal effects, we measured recovery times at around the threshold (test stimuli: 150–110% threshold) for the phosphene after pre-stimulus of 47 mT at 20 Hz for 30s. Judging from the result of the recovery times, we took notice of the possibility that there might be a latent threshold in the range of 20.8–22.4 mT for the phosphene re-perception. We strongly propose the idea that subliminal/supraliminal control with pseudo-blindsight can gradually activate synaptic plasticity and might be an effective medical treatment for the aged and the handicapped with lost visual functions. Besides, it is perfectly painless.
Autors: Hidenori Nakagawa;Shoogo Ueno;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Submodular Attribute Selection for Visual Recognition
Abstract:
In real-world visual recognition problems, low-level features cannot adequately characterize the semantic content in images, or the spatio-temporal structure in videos. In this work, we encode objects or actions based on attributes that describe them as high-level concepts. We consider two types of attributes. One type of attributes is generated by humans, while the second type is data-driven attributes extracted from data using dictionary learning methods. Attribute-based representation may exhibit variations due to noisy and redundant attributes. We propose a discriminative and compact attribute-based representation by selecting a subset of discriminative attributes from a large attribute set. Three attribute selection criteria are proposed and formulated as a submodular optimization problem. A greedy optimization algorithm is presented and its solution is guaranteed to be at least (1−1/e)-approximation to the optimum. Experimental results on four public datasets demonstrate that the proposed attribute-based representation significantly boosts the performance of visual recognition and outperforms most recently proposed recognition approaches.
Autors: Jingjing Zheng;Zhuolin Jiang;Rama Chellappa;
Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence
Publication date: Nov 2017, volume: 39, issue:11, pages: 2242 - 2255
Publisher: IEEE
 
» Subsynchronous Interaction Between Direct-Drive PMSG Based Wind Farms and Weak AC Networks
Abstract:
Recently, sustained power oscillation at subsynchronous frequency was captured in direct-drive permanent magnetic synchronous generator (PMSG) based wind farms in Xinjiang Uygur Autonomous Region, China. This new type of subsynchronous interaction (SSI) detected in practical systems has never been reported and analyzed before. Therefore, its mechanism and characteristics are not yet clearly clarified. In this paper, a simplified but representative system model with multiple PMSGs interfaced with AC networks is established first based on the actual system and the PMSG model provided by the manufacturer. Then, small-signal eigenanalysis, time-domain simulation, and impedance model analysis are carried out to investigate the interactive dynamics between them. The results show that such interaction between direct-drive PMSG wind farms and weak ac grids characterized by low short-circuit ratio would cause negative-resistance effect for the SSI mode, leading to unstable oscillation. In such cases, the controller of PMSG would saturate soon, resulting in sustained power oscillation in the system. If unfortunately the oscillation frequency matches the torsional mode of any nearby turbogenerator, severe torsional vibration would be excited on the shaft of the latter. The analysis results are finally validated with field measurements of an actual SSI event. To address the problem, a supplementary subsynchronous damping control loop is attached to the controllers of PMSGs to reshape the impedance and thus to stabilize the SSI.
Autors: Huakun Liu;Xiaorong Xie;Jingbo He;Tao Xu;Zhao Yu;Chao Wang;Chuanyu Zhang;
Appeared in: IEEE Transactions on Power Systems
Publication date: Nov 2017, volume: 32, issue:6, pages: 4708 - 4720
Publisher: IEEE
 
» Sum-Power Minimization Problem in Multisource Single-AF-Relay Networks: A New Revisit to Study the Optimality
Abstract:
For multisource single amplify-and-forward (AF) relay networks, the optimality of power allocation is revisited from different solution aspect, and a universal optimization framework is proposed. The proposed framework can be used to solve problems that have some common specific structure. As a baseline of the optimization framework, two theorems are proposed to obtain the extreme value of the problem, which is general to realize the optimal resource allocation under some system-specific constraints. Then, based on the proposed theorems, for multiuser single-AF-relay cooperative networks without direct links between sources and destinations, optimal power allocation strategies with low computational complexity are proposed to minimize sum-source-power consumption and sum-system-power consumption. When the number of mobile user is , the overall complexity of both power allocation schemes is , which is lower than or same as the existing strategies. While comparing with the traditional methods to solve this type of problem, extensive numerical simulation has been conducted for different system setups to justify the effectiveness and efficacy of our proposed power allocation schemes.
Autors: Shiguo Wang;Rukhsana Ruby;Victor C. M. Leung;Zhiqiang Yao;Xianru Liu;Zhetao Li;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Nov 2017, volume: 66, issue:11, pages: 9958 - 9971
Publisher: IEEE
 
» Sum-Rate Analysis for Multi-User MIMO Systems With User Exposure Constraints
Abstract:
Fifth generation (5G) and beyond cellular systems are expected to support multiple uplink transmit antennas. Previous research demonstrates that designing waveforms satisfying near field user exposure constraints affects the far-field data rates achievable by portable devices using multiple transmit antennas. Therefore, user exposure constraints need to be taken into account in the uplink transmission covariance matrix design (e.g., precoder design) for 5G. Specific absorption rate (SAR) is a widely accepted user exposure measurement used in wireless communication regulations throughout the world. In this paper, we perform sum-rate analysis for a multi-user multiple-input multiple-output (MIMO) system with SAR constraints enforced at each user. The maximum achievable sum rates for various channel state information at the transmitter scenarios are studied in this paper. The SAR-aware MIMO transmission methods are based on the modified waterfilling algorithm. Simulation results show our proposed methods outperform the conventional transmission strategy for the two user case.
Autors: Dawei Ying;David J. Love;Bertrand M. Hochwald;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Nov 2017, volume: 16, issue:11, pages: 7376 - 7388
Publisher: IEEE
 
» Summarizing Unconstrained Videos Using Salient Montages
Abstract:
We present a novel method to summarize unconstrained videos using salient montages (i.e., a “melange” of frames in the video as shown in Fig. 1), by finding “montageable moments” and identifying the salient people and actions to depict in each montage. Our method aims at addressing the increasing need for generating concise visualizations from the large number of videos being captured from portable devices. Our main contributions are (1) the process of finding salient people and moments to form a montage, and (2) the application of this method to videos taken “in the wild” where the camera moves freely. As such, we demonstrate results on head-mounted cameras, where the camera moves constantly, as well as on videos downloaded from YouTube. In our experiments, we show that our method can reliably detect and track humans under significant action and camera motion. Moreover, the predicted salient people are more accurate than results from state-of-the-art video salieny method [1] . Finally, we demonstrate that a novel “montageability” score can be used to retrieve results with relatively high precision which allows us to present high quality montages to users.
Autors: Min Sun;Ali Farhadi;Ben Taskar;Steve Seitz;
Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence
Publication date: Nov 2017, volume: 39, issue:11, pages: 2256 - 2269
Publisher: IEEE
 
» Super-accurate GPS coming to smartphones in 2018 [News]
Abstract:
We've all been there. You're driving down the highway, just as your navigation app instructed, when Siri tells you to "proceed east for one-half mile, then merge onto the highway." But you're already on the highway. After a moment of confusion and perhaps some rude words about Siri and her extended AI family, you realize the problem: Your GPS isn't accurate enough for your navigation app to tell if you're on the highway or on the road beside it. Those days are nearly at an end. At the Institute of Navigation GNSS+ conference in Portland, Ore., in September, Broadcom announced that it is providing customers samples of the first mass-market chip to take advantage of a new breed of global navigation satellite signals. This new chip will give the next generation of smartphones 30‑centimeter accuracy as opposed to today’s 5 meters. Even better, it works in a city's concrete canyons, and it consumes half the power of today's generation of chips. The chip, the BCM47755, has been included in the design of some smartphones slated for release in 2018, but Broadcom would not reveal which.
Autors: Samuel K. Moore;
Appeared in: IEEE Spectrum
Publication date: Nov 2017, volume: 54, issue:11, pages: 10 - 11
Publisher: IEEE
 
» Superpixels by Bilateral Geodesic Distance
Abstract:
We present a novel superpixel generation algorithm based on a new definition of geodesic distance, called bilateral geodesic distance. In contrast to the traditional geodesic distance, the new bilateral geodesic distance of two pixels considers the distance between their positions as well as their color difference. Superpixel generation is essentially a problem of clustering image pixels with respect to a set of properly selected seeds. We first use an adaptive hexagonal subdivision method to determine the initial seed-based image gradient. Then, we use the bilateral geodesic distance to measure the similarity between the pixels and the seeds. We apply an improved fast marching method to generate superpixels’ contour regions with the expansion velocities dependent on a new gradient formulation that depends on the seeds’ properties. The experimental results indicate that our algorithm is not only much faster than the structure-based method, which uses conventional geodesic distance, but also outperforms the existing methods in terms of region compactness and region boundary regularity.
Autors: Yuanfeng Zhou;Xiao Pan;Wenping Wang;Yilong Yin;Caiming Zhang;
Appeared in: IEEE Transactions on Circuits and Systems for Video Technology
Publication date: Nov 2017, volume: 27, issue:11, pages: 2281 - 2293
Publisher: IEEE
 
» Support Vector Motion Clustering
Abstract:
We present a closed-loop unsupervised clustering method for motion vectors extracted from highly dynamic video scenes. Motion vectors are assigned to nonconvex homogeneous clusters characterizing direction, size and shape of regions with multiple independent activities. The proposed method is based on support vector clustering. Cluster labels are propagated over time via incremental learning. The proposed method uses a kernel function that maps the input motion vectors into a high-dimensional space to produce nonconvex clusters. We improve the mapping effectiveness by quantifying feature similarities via a blend of position and orientation affinities. We use the Quasiconformal Kernel Transformation to boost the discrimination of outliers. The temporal propagation of the clusters’ identities is achieved via incremental learning based on the concept of feature obsolescence to deal with appearing and disappearing features. Moreover, we design an online clustering performance prediction algorithm used as a feedback that refines the cluster model at each frame in an unsupervised manner. We evaluate the proposed method on synthetic data sets and real-world crowded videos and show that our solution outperforms state-of-the-art approaches.
Autors: Isah A. Lawal;Fabio Poiesi;Davide Anguita;Andrea Cavallaro;
Appeared in: IEEE Transactions on Circuits and Systems for Video Technology
Publication date: Nov 2017, volume: 27, issue:11, pages: 2395 - 2408
Publisher: IEEE
 
» Supporting One-Time Point Annotations for Gesture Recognition
Abstract:
This paper investigates a new annotation technique that reduces significantly the amount of time to annotate training data for gesture recognition. Conventionally, the annotations comprise the start and end times, and the corresponding labels of gestures in sensor recordings. In this work, we propose a one-time point annotation in which labelers do not have to select the start and end time carefully, but just mark a one-time point within the time a gesture is happening. The technique gives more freedom and reduces significantly the burden for labelers. To make the one-time point annotations applicable, we propose a novel BoundarySearch algorithm to find automatically the correct temporal boundaries of gestures by discovering data patterns around their given one-time point annotations. The corrected annotations are then used to train gesture models. We evaluate the method on three applications from wearable gesture recognition with various gesture classes (10-17 classes) recorded with different sensor modalities. The results show that training on the corrected annotations can achieve performances close to a fully supervised training on clean annotations (lower by just up to 5 percent F1-score on average). Furthermore, the BoundarySearch algorithm is also evaluated on the ChaLearn 2014 multi-modal gesture recognition challenge recorded with Kinect sensors from computer vision and achieves similar results.
Autors: Long-Van Nguyen-Dinh;Alberto Calatroni;Gerhard Tröster;
Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence
Publication date: Nov 2017, volume: 39, issue:11, pages: 2270 - 2283
Publisher: IEEE
 
» Surface Plasmon Resonance Refractive Index Sensor Based on Tapered Coreless Optical Fiber Structure
Abstract:
In this paper, we announce the surface plasmon resonance (SPR) refractive index (RI) sensor based on tapered coreless fiber (TCF) structure. We take full advantage of the transmission characteristics of the coreless fiber, and the experimental results evidence that TCF is able to excite surface plasmon wave effectively. Compared with common SPR sensors, this sensor is easier to fabricate, has better mechanical stability, and offers a comparable sensitivity. The wavelength interrogation sensitivity of the proposed sensor is 2278.4 nm/RIU in the RI range of 1.33-1.391. As the structure of the proposed sensor can lead to multimode interference (MMI), and the gold film is only coated on one side of TCF, MMI spectra appear in the visible light band instead of in the near-infrared. When surrounding RI increases, the resonance wavelength shifts to shorter wavelengths. We get an ultrahigh wavelength interrogation sensitivity, 866.1 nm/RIU, compared with common MMI RI sensors, in the RI range of 1.3864-1.416. Because both SPR and MMI are sensitive to the change of surrounding RI, this sensor can achieve a wide detection range when we use these two phenomena together.
Autors: Zhe-Wen Ding;Ting-Ting Lang;Yu Wang;Chun-Liu Zhao;
Appeared in: Journal of Lightwave Technology
Publication date: Nov 2017, volume: 35, issue:21, pages: 4734 - 4739
Publisher: IEEE
 
» Surface Water Mapping by Deep Learning
Abstract:
Mapping of surface water is useful in a variety of remote sensing applications, such as estimating the availability of water, measuring its change in time, and predicting droughts and floods. Using the imagery acquired by currently active Landsat missions, a surface water map can be generated from any selected region as often as every 8 days. Traditional Landsat water indices require carefully selected threshold values that vary depending on the region being imaged and on the atmospheric conditions. They also suffer from many false positives, arising mainly from snow and ice, and from terrain and cloud shadows being mistaken for water. Systems that produce high-quality water maps usually rely on ancillary data and complex rule-based expert systems to overcome these problems. Here, we instead adopt a data-driven, deep-learning-based approach to surface water mapping. We propose a fully convolutional neural network that is trained to segment water on Landsat imagery. Our proposed model, named DeepWaterMap, learns the characteristics of water bodies from data drawn from across the globe. The trained model separates water from land, snow, ice, clouds, and shadows using only Landsat bands as input. Our code and trained models are publicly available at http://live.ece.utexas.edu/research/deepwatermap/.
Autors: Furkan Isikdogan;Alan C. Bovik;Paola Passalacqua;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Nov 2017, volume: 10, issue:11, pages: 4909 - 4918
Publisher: IEEE
 
» Surface-Oxidized Amorphous Alloy Powder/Epoxy-Resin Composite Bulk Magnetic Core and Its Application to Megahertz Switching LLC Resonant Converter
Abstract:
To realize a compact, lightweight and high-efficiency megahertz (MHz) switching DC–DC converter using SiC/GaN power device, inductor/transformer core must have small core loss at such high frequency to maintain high efficiency of the converter. This paper focuses on Fe-based amorphous (Fe-AMO) alloy powder used in metal composite bulk magnetic core for MHz switching DC–DC converter, where fine Fe-AMO powder with a mean diameter of was used to suppress MHz band eddy current inside the Fe-AMO powder body. When applying Fe-AMO powder to the closely packed composite core together with epoxy resin, high electrical-resistivity layer must be formed on the Fe-AMO powder surface in order to suppress the overlapped eddy current between adjacent Fe-AMO powders. In this paper, about 10 nm-thick oxidized layer of the Fe-AMO powder surface was successfully formed by using annealing in dry air. This paper describes on the surface-oxidized Fe-AMO powder/epoxy-resin composite bulk core transformer and its application to GaN power device MHz switching LLC resonant DC–DC converter. By using the Fe-AMO composite core transformer, the fabricated 48 V-input/24 V-output LLC resonant converter exhibited 90% over efficiency in the output power range of 24 to 120 W, which was higher efficiency when using the Ni–Zn ferrite core transformer.
Autors: Kanako Sugimura;Daisuke Shibamoto;Naoki Yabu;Tatsuya Yamamoto;Makoto Sonehara;Toshiro Sato;Tsutomu Mizuno;Hideaki Mizusaki;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 6
Publisher: IEEE
 
» Survivability-Aware Connectivity Restoration for Partitioned Wireless Sensor Networks
Abstract:
In this letter, we propose a survivability-aware connectivity restoration strategy for partitioned wireless sensor networks with mobile nodes. Our main contributions lie in two aspects. First, we design a load equilibrium mechanism, in which the partitioned segments are connected according to an in-order connection pattern rather than conventional factors, so as to enhance the network lifespan. Second, we design a reliability enhancement measure, in which the stopping points of mobile nodes are selected according to the surrounding node distribution status rather than conventional factors, so as to reduce the connectivity failure probability for the second destruction. In the end, simulations are conducted to demonstrate the effectiveness and advantages of our connectivity restoration scheme.
Autors: Xuxun Liu;
Appeared in: IEEE Communications Letters
Publication date: Nov 2017, volume: 21, issue:11, pages: 2444 - 2447
Publisher: IEEE
 
» Switching Controller Design With Dwell-Times and Sampling
Abstract:
We consider the problem of obtaining state dependent switching strategies for switching linear time-invariant systems which satisfy prespecified dwell-time constraints. Continuous-time strategies which yield exponential stability and a guaranteed level of performance are presented. We also consider discrete-time strategies in which the sampling time is independent of the dwell-times. A numerical example is included to validate the developed theory.
Autors: Matheus Souza;André R. Fioravanti;Martin Corless;Robert N. Shorten;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Nov 2017, volume: 62, issue:11, pages: 5837 - 5843
Publisher: IEEE
 
» Symmetric Channel Hopping for Blind Rendezvous in Cognitive Radio Networks Based on Union of Disjoint Difference Sets
Abstract:
In order to exchange control information without relying on any fixed control channel, neighboring cognitive users (CUs) in a multichannel cognitive radio network (CRN) can tune their transceivers to hop among a common set of spectrum channels and communicate when they rendezvous at a common channel in the blind fashion. Based on the combinatorial concept of the union of disjoint difference sets ( UDDS), the present paper proposes two novel symmetric channel hopping (CH) schemes, namely UDDS-SCH and UDDS-ACH, for CUs with or without a synchronized time clock, respectively, to achieve blind rendezvous. By deriving their performance metrics, we then point out that both UDDS-SCH and -ACH can be optimized by adopting a special UDDS, which can be partitioned into mutually disjoint minimal difference sets (MDSs) as many as possible. This stimulates us to further develop exhaustive and heuristic solutions for searching the optimal and suboptimal numbers of mutually disjoint MDSs at high and low computational complexities, respectively. Based on these searching results, we finally show that both UDDS-SCH and -ACH can achieve better performance metrics than most existing symmetric CH schemes and remedy one major shortcoming of the best known ones, i.e., incapability to rendezvous at an arbitrary number of spectrum channels. Numerical simulation demonstrates that, when primary users may appear at part of or all rendezvous channels, the proposed CH schemes will outperform the existing ones in terms of the average transmission throughput and time of the CRN.
Autors: Xuesong Jonathan Tan;Chao Zhou;Jie Chen;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Nov 2017, volume: 66, issue:11, pages: 10233 - 10248
Publisher: IEEE
 
» Synchronization of Pulse-Coupled Oscillators and Clocks Under Minimal Connectivity Assumptions
Abstract:
Populations of flashing fireflies, claps of applauding audience, cells of cardiac and circadian pacemakers reach synchrony via event-triggered interactions, referred to as pulse couplings. Synchronization via pulse coupling is widely used in wireless sensor networks, providing clock synchronization with parsimonious packet exchanges. In spite of serious attention paid to networks of pulse coupled oscillators, there is a lack of mathematical results, addressing networks with general communication topologies and general phase-response curves of the oscillators. The most general results of this type (Wang et al., 2012, 2015) establish synchronization of oscillators with a delay-advance phase-response curve over strongly connected networks. In this technical note we extend this result by relaxing the connectivity condition to the existence of a root node (or a directed spanning tree) in the graph. This condition is also necessary for synchronization.
Autors: Anton V. Proskurnikov;Ming Cao;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Nov 2017, volume: 62, issue:11, pages: 5873 - 5879
Publisher: IEEE
 
» Synchronization of Spin Torque Oscillators through Spin Hall Magnetoresistance
Abstract:
Spin torque oscillators placed onto a nonmagnetic heavy metal show synchronized auto-oscillations due to the coupling originating from spin Hall magnetoresistance effect. Here, we study a system having two-spin torque oscillators under the effect of the spin Hall torque, and show that switching the external current direction enables us to control the phase difference of the synchronization between in-phase and antiphase.
Autors: Tomohiro Taniguchi;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 7
Publisher: IEEE
 
» Synchronization of the Delayed Vicsek Model
Abstract:
This technical note studies the well-known Vicsek model with bounded time-varying delays. We consider the case that the communication delays appear in both position and heading transmissions, which is more realistic in practice. We derive delay-dependent conditions, imposed only on the initial state, to guarantee synchronization of the delayed linear and nonlinear Vicsek models. It is further seen from our simulations that the Vicsek model is indeed sensitive to communication delays in the sense that a large delay can destroy the synchronization behavior.
Autors: Jianying Zheng;Jiu-Gang Dong;Lihua Xie;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Nov 2017, volume: 62, issue:11, pages: 5866 - 5872
Publisher: IEEE
 
» Synopsis: A Distributed Sketch over Voluminous Spatiotemporal Observational Streams
Abstract:
Networked observational devices have proliferated in recent years, contributing to voluminous data streams from a variety of sources and problem domains. These streams often have a spatiotemporal component and include multidimensional features of interest. Processing such data in an offline fashion using batch systems or data warehouses is costly from both a storage and computational standpoint, and in many situations the insights derived from the data streams are useful only if they are timely. In this study, we propose Synopsis, an online, distributed sketch that is constructed from voluminous spatiotemporal data streams. The sketch summarizes feature values and inter-feature relationships in memory to facilitate real-time query evaluations and to serve as input to computations expressed using analytical engines. As the data streams evolve, Synopsis performs targeted dynamic scaling to ensure high accuracy and effective resource utilization. We evaluate our system in the context of two real-world spatiotemporal datasets and demonstrate its efficacy in both scalability and query evaluations.
Autors: Thilina Buddhika;Matthew Malensek;Sangmi Lee Pallickara;Shrideep Pallickara;
Appeared in: IEEE Transactions on Knowledge and Data Engineering
Publication date: Nov 2017, volume: 29, issue:11, pages: 2552 - 2566
Publisher: IEEE
 
» Synthesis of Carbon Dots on Fe3O4 Nanoparticles as Recyclable Visible-Light Photocatalysts
Abstract:
Carbon dots (C-dots)/Fe3O4 nanocomposite powders were synthesized by bottom-up procedures at 140 °C with different reaction times (–18 h), to study the photocatalytic activity under visible light and recyclable ability in wastewater treatment. The results from vibrating sample magnetometer, X-ray diffraction, and Fourier transform infrared spectra indicated that C-dots were gradually attached on Fe3O4 nanoparticles with the increase of t, and C-dots/Fe3O4 nanocomposite powders were obtained. The microstructure images confirmed that magnetic Fe3O4 nanoparticles were surrounded by C-dots. The C-dots/Fe3O4 nanocomposite powders presented photocatalytic ability in visible light ( nm). In this paper, higher extent of degradation was addressed in a larger amount of C-dots on Fe3O4 nanoparticles surface. Methylene blue (MB) concentration can be decreased by 83% within 30 min exposing time. The C-dots/Fe3O4 nanocomposite powders exhibited good degradation ability for MB under visible light and could be easily recycled by applied magnetic field after photodegradation.
Autors: Ruey-Shin Juang;Yin-Cheng Ju;Chien-Shiun Liao;Kuen-Song Lin;Hsi-Chuan Lu;Sea-Fue Wang;An-Cheng Sun;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Tales from the Birth of Internet Commerce
Abstract:
From the first public use of the World Wide Web in 1993, online commerce has been at the top of the minds of consumers, businesses, and software developers. This was before Twitter or Facebook, prior to the iPhone, pre-Google, and ahead of eBay or Amazon. In those days, the dominant provider of consumer online services was America Online (AOL). AOL was initially a closed system, mediating every online interaction by every user, including payment transactions. When AOL began offering Internet access to its users, it almost immediately became the largest consumer Internet service provider.
Autors: Jason May;
Appeared in: IEEE Potentials
Publication date: Nov 2017, volume: 36, issue:6, pages: 24 - 27
Publisher: IEEE
 
» Task-Independent Mental Workload Classification Based Upon Common Multiband EEG Cortical Connectivity
Abstract:
Efficient classification of mental workload, an important issue in neuroscience, is limited, so far to single task, while cross-task classification remains a challenge. Furthermore, network approaches have emerged as a promising direction for studying the complex organization of the brain, enabling easier interpretation of various mental states. In this paper, using two mental tasks (N-back and mental arithmetic), we present a framework for cross- as well as within-task workload discrimination by utilizing multiband electroencephalography (EEG) cortical brain connectivity. In detail, we constructed functional networks in EEG source space in different frequency bands and considering the individual functional connections as classification features, we identified salient feature subsets based on a sequential feature selection algorithm. These connectivity subsets were able to provide accuracy of 87% for cross-task, 88% for N-back task, and 86% for mental arithmetic task. In conclusion, our method achieved to detect a small number of discriminative interactions among brain areas, leading to high accuracy in both within-task and cross-task classifications. In addition, the identified functional connectivity features, the majority of which were detected in frontal areas in theta and beta frequency bands, helped delineate the shared as well as the distinct neural mechanisms of the two mental tasks.
Autors: Georgios N. Dimitrakopoulos;Ioannis Kakkos;Zhongxiang Dai;Julian Lim;Joshua J. deSouza;Anastasios Bezerianos;Yu Sun;
Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Publication date: Nov 2017, volume: 25, issue:11, pages: 1940 - 1949
Publisher: IEEE
 
» TC-Release++: An Efficient Timestamp-Based Coherence Protocol for Many-Core Architectures
Abstract:
As we enter the era of many-core, providing the shared memory abstraction through cache coherence has become progressively difficult. The standard directory-based coherence does not scale well with increasing core count. Timestamp-based hardware coherence protocols introduced recently offer an attractive alternative solution. This paper proposes a timestamp-based coherence protocol, called TC-Release++ , that efficiently supports cache coherence in large-scale systems. Our approach is inspired by TC-Weak, a recently proposed timestamp-based coherence protocol targeting GPU architectures. We first design TC-Release in an attempt to straightforwardly port TC-Weak to general-purpose many-cores. But re-purposing TC-Weak for general-purpose many-core architectures is challenging due to significant differences both in architecture and the programming model. Indeed the performance of TC-Release turns out to be worse than conventional directory protocols. We overcome the limitations and overheads of TC-Release by exploiting simple hardware support to eliminate frequent memory stalls, and an optimized lifetime prediction mechanism to improve cache performance. The resulting optimized coherence protocol TC-Release++ is highly scalable (storage scales logarithmically with core count) and shows better performance (3.0 percent) and comparable network traffic (within 1.3 percent) relative to the baseline MESI directory protocol. We use Murphi to formally verify that TC-Release ++ is error-free and imposes small verification cost.
Autors: Yuan Yao;Wenzhi Chen;Tulika Mitra;Yang Xiang;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Nov 2017, volume: 28, issue:11, pages: 3313 - 3327
Publisher: IEEE
 
» Teaching Tool for a Control Systems Laboratory Using a Quadrotor as a Plant in MATLAB
Abstract:
This paper presents a MATLAB-based application to teach the guidance, navigation, and control concepts of a quadrotor to undergraduate students, using a graphical user interface (GUI) and 3-D animations. The Simulink quadrotor model is controlled by a proportional integral derivative controller and a linear quadratic regulator controller. The GUI layout’s many components can be easily programmed to perform various experiments by considering the simulation of the quadrotor as a plant; it incorporates control systems (CS) fundamentals such as time domain response, transfer function and state-space form, pole-zero location, root locus, frequency domain response, steady-state error, position and disturbance response, controller design and tuning, unity, and the use of a Kalman filter as a feedback sensor. 3-D animations are used to display the quadrotor flying in any given condition selected by the user. For each simulation, users can view the output response in the form of 3-D animations, and can run time plots. The quadrotor educational tool (QET) helps students in the CS laboratory understand basic CS concepts. The QET was evaluated based on student feedback, grades, satisfaction, and interest in CS.
Autors: Subhan Khan;Mujtaba Hussain Jaffery;Athar Hanif;Muhammad Rizwan Asif;
Appeared in: IEEE Transactions on Education
Publication date: Nov 2017, volume: 60, issue:4, pages: 249 - 256
Publisher: IEEE
 
» Temperature Effect Inversion-Aware Power-Performance Optimization for FinFET-Based Multicore Systems
Abstract:
Energy and temperature are the main constraints for modern high-performance multicore systems. To save power or increase performance, dynamic voltage and frequency scaling (DVFS) is widely applied in literally all computing systems. As CMOS technology continues scaling, FinFET has recently become the common choice for multicore systems. In contrast with planar CMOS, FinFET is characterized by lower delay under higher temperatures in super-threshold voltage region, an effect called temperature effect inversion (TEI). This paper explores TEI-aware performance improvement and energy savings for multicore systems. Our experimental results show that on average 15.70% throughput improvement or 31.26% energy savings can be achieved in steady state by a TEI-aware DVFS policy over a TEI-agnostic one. By further investigation, multiple sweet spots (SSs) resulting from TEI effects are observed. Based on these SS operation regimes, this paper introduces fast algorithms which provide iso-power maximum performance or iso-performance minimum energy consumption. Experimental results confirm the effectiveness of the proposed approach by exhibiting a – speedup when compared to state-of-the-art algorithms while losing only 0.22% or 0.68% in achieved performance or energy, respectively.
Autors: Ermao Cai;Diana Marculescu;
Appeared in: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Publication date: Nov 2017, volume: 36, issue:11, pages: 1897 - 1910
Publisher: IEEE
 
» Temperature Effects on the Magnetoimpedance in Glass-Coated Amorphous Wires
Abstract:
The temperature dependence of magnetoimpedance (MI) in glass-coated amorphous microwires of two compositions Co66.94Fe3.83Ni1.44B11.51Si14.59Mo1.69 and Co23.67Fe7.14Ni43.08B13.85Si12.26 having high (613 K) and low (335 K) Curie temperatures, respectively, was investigated. The wires of the first type have a small negative magnetostriction and are widely used as MI sensing elements. For sensor operation, the temperature stability is of primary importance, however, it was found that the MI change at moderate temperatures of 20 °C–90 °C and low magnetic fields can be nearly 200%. This is explained by high temperature sensitivity of the residual stress and stress-dependent magnetostriction, which resulted in abrupt change in the easy anisotropy direction. The wires of the second type with low Curie temperature and positive magnetostriction demonstrate large and sensitive change in impedance only in the vicinity of due to a corresponding drop in the magnetization saturation and magnetostriction, whilst the bistable type of the magnetization reversal remains. The frequency dispersion of the dynamical permeability shifts toward lower frequencies when approaching suppressing the high-frequency properties and MI. Such temperature dependence of MI is well controllable and is proposed for applications in temperature sensors.
Autors: A. Dzhumazoda;L. V. Panina;A. M. Adam;N. A. Yudanov;R. Awale;A. T. Morchenko;S. V. Podgornaya;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Temperature-Driven Changes of Electronic Structure Through the Phase Transition in Magnetocaloric Compound Mn1.1Fe0.9P0.55As0.45
Abstract:
The electronic structure of magnetocaloric compound Mn1.1Fe0.9P0.55As0.45, prepared via solid-state sintering was studied. Adiabatic temperature change of 3.6 K was observed through the phase transition found at 273 K. The X-ray diffraction and time-of-flight secondary ion mass spectroscopy were applied to verify the purity and homogeneity of the sample. The X-ray photoemission spectroscopy was used to study electronic structure at room temperature and below the phase transition at 180 K. The existence of local magnetic moment was deduced from the exchange splitting effect found for 2p states of manganese. This effect was also studied below the phase transition at low temperature. It was reflected in the shape of the valence band. A shift of 0.15 eV was detected on the onset of the valence band at low temperature. The splitting of the 3s core lines of manganese and iron were investigated. The values of these splitting were obtained. No influence of phase transition was found on the photoemission spectra from iron 2p, phosphorus 2p, and arsenic 3d states.
Autors: J. Kubacki;K. Balin;M. Kulpa;Ł. Hawełek;P. Włodarczyk;P. Zackiewicz;M. Kowalczyk;J. Szade;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Temporal Conformance Analysis and Explanation of Clinical Guidelines Execution: An Answer Set Programming Approach
Abstract:
Clinical Guidelines (CGs) provide general evidence-based recommendations and physicians often have to resort also to their Basic Medical Knowledge (BMK) to cope with specific patients. In this paper, we explore the interplay between CGs and BMK from the viewpoint of a-posteriori conformance analysis, intended as the adherence of a specific execution log to both the CG and the BMK. In this paper, we consider also the temporal dimension: the guideline may include temporal constraints for the execution of actions, and its adaptation to a specific patient and context may add or modify conditions and temporal constraints for actions. We propose an approach for analyzing execution traces in Answer Set Programming with respect to a guideline and BMK, pointing out discrepancies – including temporal discrepancies – with respect to the different knowledge sources, and providing explanations regarding how the applications of the CG and the BMK have interacted, especially in case strictly adhering to both is not possible.
Autors: Matteo Spiotta;Paolo Terenziani;Daniele Theseider Dupré;
Appeared in: IEEE Transactions on Knowledge and Data Engineering
Publication date: Nov 2017, volume: 29, issue:11, pages: 2567 - 2580
Publisher: IEEE
 
» Terahertz Imaging of Cutaneous Edema: Correlation With Magnetic Resonance Imaging in Burn Wounds
Abstract:
Objective: In vivo visualization and quantification of edema, or ‘tissue swelling’ following injury, remains a clinical challenge. Herein, we investigate the ability of reflective terahertz (THz) imaging to track changes in tissue water content (TWC)—the direct indicator of edema—by comparison to depth-resolved magnetic resonance imaging (MRI) in a burn-induced model of edema. Methods: A partial thickness and full thickness burns were induced in an in vivo rat model to elicit unique TWC perturbations corresponding to burn severity. Concomitant THz surface maps and MRI images of both burn models were acquired with a previously reported THz imaging system and T2-weighted MRI, respectively, over 270 min. Reflectivity was analyzed for the burn contact area in THz images, while proton density (i.e., mobile TWC) was analyzed for the same region at incrementally increasing tissue depths in companion, transverse MRI images. A normalized cross correlation of THz and depth-dependent MRI measurements was performed as a function of time in histologically verified burn wounds. Results: For both burn types, strong positive correlations were evident between THz reflectivity and MRI data analyzed at greater tissue depths (>258 μm). MRI and THz results also revealed biphasic trends consistent with burn edema pathogenesis. Conclusion: This paper offers the first in vivo correlative assessment of mobile TWC-based contrast and the sensing depth of THz imaging. Significance: The ability to implement THz imaging immediately following injury, combined with TWC sensing capabilities that compare to MRI, further support THz sensing as an emerging tool to track fluid in tissue.
Autors: Neha Bajwa;Shijun Sung;Daniel B. Ennis;Michael C. Fishbein;Bryan N. Nowroozi;Dan Ruan;Ashkan Maccabi;Jeffry Alger;Maie A. St. John;Warren S. Grundfest;Zachary D. Taylor;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Nov 2017, volume: 64, issue:11, pages: 2682 - 2694
Publisher: IEEE
 
» Test Zone Size Characterization With Measured MIMO Throughput for Simulated MPAC Configurations in Conductive Setups
Abstract:
This correspondence discusses over-the-air (OTA) testing for multiple-input multiple-output (MIMO) capable terminals, with an emphasis on test zone size characterization for multi-probe anechoic chamber (MPAC) OTA configurations. For an MPAC setup, it is important to understand the test zone size that can be supported by its design. Further, it is desirable that the test zone size should be determined in terms of measured throughput deviation. However, such works have not been reported in the literature yet, due to challenges in practical MPAC setups. In this correspondence, we propose to simulate the MPAC OTA configuration and MS design in a channel emulator and perform MIMO throughput measurements in a conductive setup. With the proposed scheme, we can investigate how large a test zone can be supported for the synthetic MPAC configuration in terms of throughput deviation. This scheme is attractive, since various MS antenna designs and MPAC configurations can be flexibly selected and test zone size in terms of measured MIMO throughput deviation can be achieved. Measurement results show that with a high antenna correlation at the base station (BS) side, measured throughput results would be low, irrelevant to MPAC OTA designs and antenna designs at the MS side. Therefore, the antenna correlation at BS side should be set uncorrelated to ensure that true MS performance can be measured. Further, spatial correlation accuracy at the MS side becomes critical for throughput accuracy only when correlation values are in the high region (e.g., ).
Autors: Wei Fan;Lassi Hentilä;Pekka Kyösti;Gert F. Pedersen;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Nov 2017, volume: 66, issue:11, pages: 10532 - 10536
Publisher: IEEE
 
» Testing Equality in Communication Graphs
Abstract:
Let be a connected undirected graph with vertices. Suppose that on each vertex of the graph there is a player having an -bit string. Each player is allowed to communicate with its neighbors according to a (static) agreed communication protocol, and the players must decide, deterministically, if their inputs are all equal. What is the minimum possible total number of bits transmitted in a protocol solving this problem ? We determine this minimum up to a lower order additive term in many cases. In particular, we show that it is for any Hamiltonian -vertex graph, and that for any 2-edge connected graph with edges containing no two adjacent vertices of degree exceeding 2 it is . The proofs combine graph theoretic ideas with tools from additive number theory.
Autors: Noga Alon;Klim Efremenko;Benny Sudakov;
Appeared in: IEEE Transactions on Information Theory
Publication date: Nov 2017, volume: 63, issue:11, pages: 7569 - 7574
Publisher: IEEE
 
» Testing from Partial Finite State Machines without Harmonised Traces
Abstract:
This paper concerns the problem of testing from a partial, possibly non-deterministic, finite state machine (FSM) . Two notions of correctness (quasi-reduction and quasi-equivalence) have previously been defined for partial FSMs but these, and the corresponding test generation techniques, only apply to FSMs that have harmonised traces. We show how quasi-reduction and quasi-equivalence can be generalised to all partial FSMs. We also consider the problem of generating an -complete test suite from a partial FSM : a test suite that is guaranteed to determine correctness as long as the system under test has no more than states. We prove that we can complete to form a completely-specified non-deterministic FSM such that any -complete test suite generated from can be converted into an -complete test suite for . We also show that there is a correspondence between test suites that are reduced for and and also that are minimal for and .
Autors: Robert Mark Hierons;
Appeared in: IEEE Transactions on Software Engineering
Publication date: Nov 2017, volume: 43, issue:11, pages: 1033 - 1043
Publisher: IEEE
 
» Textile Frequency Selective Surface
Abstract:
Frequency selective surfaces (FSSs) are ubiquitous on rigid substrates and increasingly on flexible polymeric substrates. Here, we developed a FSS on a textile which is neither rigid nor smooth. We fabricate a textile capable of rejecting the millimeter-wave radiation in a narrowband, while retaining desirable textile properties such as flexibility and breathability. The resonators and resonant wavelength are on the order of the weave pitch. Durability tests are performed and spectral response is measured.
Autors: Michael Ghebrebrhan;Francisco Aranda;Gary Walsh;David Ziegler;Stephen Giardini;Joel Carlson;Brian Kimball;Diane Steeves;Zhiyu Xia;Shiran Yu;Edward Kingsley;Ramaswamy Nagarajan;Jojit Torcedo;Richard Williams;Andrew Gatesman;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Nov 2017, volume: 27, issue:11, pages: 989 - 991
Publisher: IEEE
 
» Texture Plus Depth Video Coding Using Camera Global Motion Information
Abstract:
In video coding, traditional motion estimation methods work well for videos with camera translational motion, but their efficiency drops for other motions, such as rotational and dolly motions. In this paper, a motion-information-based three-dimensional (3D) video coding method is proposed for texture plus depth 3D video. The synchronized global motion information of the camera is obtained to assist the encoder improve its rate-distortion performance by projecting the temporal neighboring texture and depth frames into the position of the current frame, using the depth and camera motion information. Then, the projected frames are added into the reference buffer list as virtual reference frames. As these virtual reference frames could be more similar to the current to-be-encoded frame than the conventional reference frames, the required bits to represent the residual will be reduced. The experimental results demonstrate that the proposed scheme enhances the coding performance for all camera motion types and for various scene settings and resolutions using H.264 and HEVC standards, respectively. With the computer graphic sequences, for H.264, the average gain of texture and depth coding are up to 2 dB and 1 dB, respectively. For HEVC and HD resolution sequences, the gain of texture coding reaches 0.4 dB. For realistic sequences, up to 0.5 dB gain (H.264) is achieved for the texture video, while up to 0.7 dB gain is achieved for the depth sequences.
Autors: Fei Cheng;Tammam Tillo;Jimin Xiao;Byeungwoo Jeon;
Appeared in: IEEE Transactions on Multimedia
Publication date: Nov 2017, volume: 19, issue:11, pages: 2361 - 2374
Publisher: IEEE
 
» The “Art of Trellis Decoding” Is Fixed-Parameter Tractable
Abstract:
Given subspaces of a finite-dimensional vector space over a fixed finite field , we wish to find a linear layout of the subspaces such that for all ; such a linear layout is said to have width at most . When restricted to 1-dimensional subspaces, this problem is equivalent to computing the trellis-width (or minimum trellis state-complexity) of a linear code in coding theory and computing the path-width of an -represented matroid in matroid theory. We present a fixed-parameter tractable algorithm to construct a linear layout of width at most , if it exists, for input subspaces of a finite-dimensional vector space over . As corollaries, we obtain a fixed-parameter tractable algorithm to produce a path-decomposition of width at most for an input -represented matroid of path-width at most , and a fixed-parameter tractable algorithm to find a linear rank-decomposition of width at most for an input graph of linear rank-width at most . In both corollaries, no such algorithms were known previously. Our approach is based on dynamic programming combined with the idea developed by Bodlaender and Kloks (1996) for their work on path-width and tree-width of graphs. It was previously known that a fixed-parameter tractable algorithm exists for the decision version of the problem for matroid path-width; a theorem by Geelen, Gerards, and Whittle (2002) implies that for each fixed finite field , there are finitely many forbidden -representable minors for the class of matroids of path-width at most . An algorithm by Hliněný (2006) can detect a minor in an input -represented matroid of bounded branch-width. However, this indirect approach would not produce an actual path-decomposition. Our algorithm is the first one to construct such a path-decomposition and does not depend on the finiteness of forbidden minors.
Autors: Jisu Jeong;Eun Jung Kim;Sang-il Oum;
Appeared in: IEEE Transactions on Information Theory
Publication date: Nov 2017, volume: 63, issue:11, pages: 7178 - 7205
Publisher: IEEE
 
» The 5G Effect on RF Filter Technologies
Abstract:
A great deal is being written about the next generation mobile standards, “5G.” As with the early stages of previous generations, it is hard to clearly see the direction forward. The intersection of technological obstacles, economic realities, and political forces produces a path that is not only difficult to predict but curiously interesting in retrospect. Even with this history we press on and predict—it is our way. Even with all the publications on 5G and its many technical challenges there is a dearth of information on the radio frequency (RF) filters required. This is somewhat surprising as filters have become a major part of the radio in a mobile phone. State of the art smartphones now contain more than 60 filters and command the largest share of the RF wallet. The key starting point is the proposed new RF bands that will be used for 5G. The FCC has recently proposed band sections between 3.5–6 GHz, 27–40 GHz, and 64–71 GHz. As anyone familiar with radios in these areas knows, each band commands its own set of issues and solutions. The span of filter solutions for 5G will be more diverse than in the current mobile technology bands.
Autors: Steven Mahon;
Appeared in: IEEE Transactions on Semiconductor Manufacturing
Publication date: Nov 2017, volume: 30, issue:4, pages: 494 - 499
Publisher: IEEE
 
» The Anisotropy of the AC Susceptibility of Immobilized Magnetic Nanoparticles—the Influence of Intra-Potential-Well Contribution on the AC Susceptibility Spectrum
Abstract:
We have experimentally verified the ac susceptibility model by Shliomis and Stepanov which accounts for the anisotropy caused by the different directions of the easy axes of the magnetic nanoparticle (MNP) cores with respect to the applied ac magnetic field. To experimentally access the anisotropy, single-core MNPs were immobilized in the absence of a magnetic field, thus causing random orientations of easy axes, and in a static magnetic field of 170 mT, thus orienting the nanoparticles’ easy axes either parallel or perpendicular to the ac field. In agreement with theory, the real part of the sample with easy axes aligned perpendicularly to the ac field is constant while the imaginary part is zero. In contrast, the real part of the sample with parallel-oriented easy axes decays with increasing frequency. The susceptibility spectra of the sample with random orientation of easy axes are in between the other two cases according to /3. This anisotropic behavior also explains why the real part of suspensions of thermally blocked MNPs does not drop down to zero at high frequencies but to a finite value. This value allows one to independently estimate the effective anisotropy constant of MNPs.
Autors: Frank Ludwig;Christoph Balceris;Christer Johansson;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» The Capacity of Bernoulli Nonadaptive Group Testing
Abstract:
We consider nonadaptive group testing with Bernoulli tests, where each item is placed in each test independently with some fixed probability. We give a tight threshold on the maximum number of tests required to find the defective set under optimal Bernoulli testing. Achievability is given by a result of Scarlett and Cevher; here we give a converse bound showing that this result is best possible. Our new converse requires three parts: a typicality bound generalising the trivial counting bound, a converse on the COMP algorithm of Chan et al., and a bound on the SSS algorithm similar to that given by Aldridge, Baldassini, and Johnson. Our result has a number of important corollaries, in particular that, in denser cases, Bernoulli nonadaptive group testing is strictly worse than the best adaptive strategies.
Autors: Matthew Aldridge;
Appeared in: IEEE Transactions on Information Theory
Publication date: Nov 2017, volume: 63, issue:11, pages: 7142 - 7148
Publisher: IEEE
 
» The Effect of Modulating Ring Design on Magnetic Gear Torque
Abstract:
An investigation into a magnetic gear modulating ring design geometry and the performance of a magnetic gear is presented. Modulating ring construction is one of the more difficult aspects of magnetic gear design, and a compromise between magnetic performance, losses in conductive supporting parts, and manufacturability is often required. Three possible designs for modulating rings are presented, and their magnetic performance compared with an ideal but unrealistic case of independent modulating parts.
Autors: D. Z. Abdelhamid;A. M. Knight;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» The Effect of Prosthesis Use on Hand Mental Rotation After Unilateral Upper-Limb Amputation
Abstract:
Amputation of a limb induces changes in the so-called body schema, which might be influenced by the use of prosthetic devices. Changes in the body representation associated with prosthesis use could be investigated using a hand mental rotation task. However, direct neurophysiologic evidence for the effect of prosthesis use on hand mental rotation is still lacking. In this paper, we recruited two groups of unilateral upper-limb amputees, i.e., amputees using a prosthesis or with a history of prosthesis use (Pro group) and amputees without a prosthesis (non-Pro group), as well as a sample of matched healthy controls. Using concurrent behavioral and electrophysiological assessments, we found that Pro amputees were comparable to healthy controls in either behavior or event-related potentials (ERPs), while non-Pro amputees showed prolonged response time as well as divergent ERP patterns. The P200 amplitude of non-Pro amputees was significantly larger for the non-dominant hand pictures than that for the dominant hand pictures, while such a hand difference in P200 was not found in either healthy controls or Pro amputees. Furthermore, the typical angular modulation of the N200 amplitude in healthy controls and Pro amputees was not presented in non-Pro amputees. Our results suggest that prosthesis use could preserve mental rotation ability by maintaining the performance of motor imagery and visual perception of hands, which represents a preservation of the body schema.
Autors: Xiaoli Guo;Zixuan Lin;Yuanyuan Lyu;Robin Bekrater-Bodmann;Herta Flor;Shanbao Tong;
Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Publication date: Nov 2017, volume: 25, issue:11, pages: 2046 - 2053
Publisher: IEEE
 
» The Elusiveness of Smart Healthcare
Abstract:
To realize smart healthcare’s many benefits, researchers and practitioners must overcome significant hurdles. The problems they face mirror the challenges of the field of software engineering in a world gradually eaten up by software.
Autors: Diomidis Spinellis;
Appeared in: IEEE Software
Publication date: Nov 2017, volume: 34, issue:6, pages: 4 - 6
Publisher: IEEE
 
» The End of the Manufacturing-Line Analogy
Abstract:
A trip to the BMW Group’s Leipzig plant led to the perhaps counterintuitive realization that software development isn’t a linear manufacturing process.
Autors: Mik Kersten;
Appeared in: IEEE Software
Publication date: Nov 2017, volume: 34, issue:6, pages: 89 - 93
Publisher: IEEE
 
» The Fabrication and Sensing Characteristics of Arrayed Flexible IGZO/Al Urea Biosensor Modified by Graphene Oxide
Abstract:
The urease membrane was immobilized on the surface of indium gallium zinc oxide (IGZO) based on polyethylene terephthalate substrate, which was used to develop an arrayed flexible urea biosensor in this study. In order to improve the properties of arrayed flexible IGZO/Al urea biosensor, graphene oxide (GO) was employed to modify the properties of arrayed flexible IGZO urea biosensor. Compared with the average sensitivity of 1.53 mV/(mg/dl) and linearity of 0.931 for arrayed flexible IGZO/Al urea biosensor, the average sensitivity and linearity of arrayed flexible IGZO urea biosensor modified by GO achieved 3.06 mV/(mg/dl) and 0.970, respectively. As the result, 5 mM pH 7.0 PBS buffer solution was the optimal measurement environment for Urease/IGZO/GO/Al urea biosensor, and which the average sensitivity was 3.65 [mV/(mg/dl)]. Anti-interference testing showed the arrayed flexible IGZO/Al urea biosensor modified by GO was not easily interfered from the other materials.
Autors: Jung-Chuan Chou;Hong-Yu Huang;Yi-Hung Liao;Chih-Hsien Lai;Siao-Jie Yan;Cian-Yi Wu;You-Xiang Wu;
Appeared in: IEEE Transactions on Nanotechnology
Publication date: Nov 2017, volume: 16, issue:6, pages: 958 - 964
Publisher: IEEE
 
» The fight to fix it
Abstract:
THE CONSUMER TECHNOLOGY ASSOCIATION estimated that residents of the United States bought 183 million smartphones in 2016. There are already as many TVs in this country as there are people. That's a lot of electronics, and these numbers are just going up. On balance, all this technology is probably making our lives better. But there’s a downside, too: The stuff often malfunctions. Unlike the 30-year-old mixer on your kitchen counter that refuses to die, new technology— especially the smart devices with fancy, embedded electronics—breaks more quickly. That trend, confirmed by a recent study by the German government, applies not just to delicate products like smartphones and tablets but also to equipment we would expect to last for a long time— like televisions, washing machines, and even tractors.
Autors: Kyle Wiens;Gay Gordon-Byrne;
Appeared in: IEEE Spectrum
Publication date: Nov 2017, volume: 54, issue:11, pages: 24 - 29
Publisher: IEEE
 
» The fiight to fix
Abstract:
THE CONSUMER TECHNOLOGY ASSOCIATION estimated that residents of the United States bought 183 million smartphones in 2016. There are already as many TVs in this country as there are people. That's a lot of electronics, and these numbers are just going up. On balance, all this technology is probably making our lives better. But there’s a downside, too: The stuff often malfunctions. Unlike the 30-year-old mixer on your kitchen counter that refuses to die, new technology— especially the smart devices with fancy, embedded electronics—breaks more quickly. That trend, confirmed by a recent study by the German government, applies not just to delicate products like smartphones and tablets but also to equipment we would expect to last for a long time— like televisions, washing machines, and even tractors.
Autors: Kyle Wiens;Gay Gordon-Byrne;
Appeared in: IEEE Spectrum
Publication date: Nov 2017, volume: 54, issue:11, pages: 24 - 29
Publisher: IEEE
 
» The Future of Shopping: An Eerie Silence?
Abstract:
Technology is poised to transform shopping in radical new ways. But could we be overautomating overselves into an eerie silence?
Autors: Brian David Johnson;
Appeared in: Computer
Publication date: Nov 2017, volume: 50, issue:11, pages: 91 - 91
Publisher: IEEE
 
» The IEEE International Magnetics Conference 2017 Foreword
Abstract:
The IEEE International Magnetics Conference, Intermag Europe 2017, was held in Dublin, Ireland, from April 24–28, 2017. There were 1470 registrants from over 50 countries (including 45% from Europe, 37% from Asia, and 10% from the USA). A total of 2060 contributed digests were submitted, 73% of which were accepted, together with 96 invited digests. There were 56 oral sessions, 59 poster sessions, and eight special symposia covering the following topics: Magnetocaloric Materials: New Concepts for Energy Application; Smart City, Smart Living; Bio-Applied Magnetism; Additive Manufacturing and 3D Printing of Magnets; When THz Meets X-rays: An Ultrafast View on Magnetism; Magnetic Micro- and Nano-Actuators and Robots; STT-MRAM: Toward Volume Production; and Spin-Dependent Phenomena in 2D Materials and van der Waals Heterostructures. A total of 654 papers were submitted, 425 of which were accepted for publication in this issue of the IEEE Transactions on Magnetics.
Autors: Nora Dempsey;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 2
Publisher: IEEE
 
» The IEEE International Magnetics Conference 2017 Publication Chairs’ Preface
Abstract:
On behalf of the Publications Committee, it is our pleasure to present selected papers from the Intermag 2017 Conference, which was held in Dublin, Ireland, from April 24–28, 2017. The outstanding quality of the conference is reflected by the scientific and technical quality of the papers presented in this special issue of the IEEE Transactions on Magnetics. The Publications Committee received 654 manuscripts which were submitted for peer review and possible publication in the present volume. In order to be considered for publication, the manuscripts were required to meet rigorous criteria for novelty in applied and basic magnetism. Following the standard IEEE review process, each paper was reviewed by at least two anonymous referees, and in the end, 425 papers were accepted for publication.
Autors: Petru Andrei;S. N. Piramanayagam Prem;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 1
Publisher: IEEE
 
» The Impact of Modal Interactions on Receiver Complexity in OAM Fibers
Abstract:
We experimentally study the modal interactions in mode division multiplexing (MDM) links supporting orbital angular momentum (OAM) modes of order zero and one. We use time of flight and channel impulse response measurements to characterize our OAM-MDM link and quantify modal impairments. We examine two OAM fibers with different index profiles and differential mode group delays (DMGD) between supported vector modes. Data transmission experiments probe the impact of modal impairments on digital signal processing complexity and achievable bit error rate for OAM-MDM link. We discuss in particular memory depth requirements for equalizers in separate mode detection schemes, and how memory depth varies with DMGD metrics as well as crosstalk level.
Autors: Reza Mirzaei Nejad;Lixian Wang;Jiachuan Lin;Sophie LaRochelle;Leslie Ann Rusch;
Appeared in: Journal of Lightwave Technology
Publication date: Nov 2017, volume: 35, issue:21, pages: 4692 - 4699
Publisher: IEEE
 
» The Influence of Edge Inhomogeneities on Vortex Hysteresis Curves in Magnetic Tunnel Junctions
Abstract:
Magnetoresistive sensors using a tunnel magnetoresistance (TMR) spin valve structure with CoFe and CoFeB free layer (FL) are investigated. Lateral dimension, thickness, and magnetic properties of the circular-shaped FL energetically favor the nucleation of a magnetic vortex. In the vortex configuration, the sensors show the expected hysteresis-free transfer curve. Distinct differences between CoFe and CoFeB in the vortex typical parameters are observed. The experimental results are compared to micromagnetic simulations. Influence of saturation magnetization on the vortex transfer curve is studied in order to reproduce the experimental data. However, only by adjusting iteratively the experimental data cannot be fully reproduced: The vortex annihilation () in CoFeB occurs at smaller fields than simulated. On the other hand, the change in TMR signal at is significantly smaller in the experiment for CoFe. Discrepancies are most pronounced at . This investigation focuses on the magnetic and electric properties at the edge of the FL structure. Reduction in can be explained for 1.1 FL diameters by introducing a magnetically disturbed edge. Reduced change in TMR signal at can be understood by introducing an electrically inactive edge area. The analysis shows that f- r CoFe and CoFeB different edge inhomogeneity effects are present or edge inhomogeneities have different impacts.
Autors: T. Wurft;W. Raberg;K. Prügl;A. Satz;G. Reiss;H. Brückl;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» The Iterative Reweighted Alternating Direction Method of Multipliers for Separating Structural Layovers in SAR Tomography
Abstract:
Layover scatterers of tall building structures can be separated by synthetic aperture radar tomography (SAR-tomo). An iterative reweighted L1 minimization (IRL1) has been applied to enhance the sparsity in a tomographic inversion, where the basis pursuit (BP) technique was adopted to search for the solution. However, the IRL1 with BP is highly time-consuming, which may prevent its real application to large-scale data sets. In this letter, we propose the iterative reweighted alternating direction method of multipliers (IR-ADMM) for fast SAR-tomo imaging. We demonstrate and validate the enhanced sparsity and fast convergence of our IR-ADMM algorithm with experiments using both simulated data and TerraSAR-X Stripmap images of tall urban buildings. The experimental results show that compared with conventional IR-BP, the IR-ADMM greatly reduces the computation time without substantial performance degradation.
Autors: Xiao Wang;Feng Xu;Ya-Qiu Jin;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Nov 2017, volume: 14, issue:11, pages: 1883 - 1887
Publisher: IEEE
 
» The Magnetic Differentiation Technique for GMI Sensor
Abstract:
The “magnetic differentiation” technique is an original method for magnetic-field measurement. It is used for giant magnetoimpedance (GMI) sensors. The response is very different from the classical impedance measurement. To measure the external field , small increments of magnetic field, alternatively positive and negative , are added to by a small coil around the GMI wire. The measured signal is the slope of the curve of the impedance . The “magnetic differentiation” technique exhibits many advantages. The obtained response is a relatively simple curve with an odd symmetry. The zero of the sensor exactly corresponds to the zero magnetic field. The sensor is able to measure the “absolute zero” field, without any zero-adjustment. Around the zero-field point, the response is linear for a range of several tenths of A/m, with a very high sensitivity. The sensor response around the zero stays constant when the GMI wire is submitted to variable influence parameters, such as temperature or strain. Moreover, the measurement of high magnetic field can be easily made with an additional coil supplied by a closed-loop system; the operation point remains around the zero-field. Globally, the magnetic differentiation technique is an original way of using the GMI effect. The null signal at zero magnetic field, the linearity around the zero, and the odd response are very interesting properties, allowing the development of a new generation of GMI sensors.
Autors: Jean-Paul Yonnet;Aktham Asfour;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» The Mobile Phone as Surveillance Device: Progress, Perils, and Protective Measures
Abstract:
Mobile phones remain the most efficient surveillance mechanism, allowing a variety of tracking and monitoring techniques to be concentrated in a single always-on device. Although the risk of unwanted monitoring persists, with protective measures to mitigate vulnerabilities, ubiquitous mobile phones will continue to provide unmatched surveillance capabilities.
Autors: Henry B. Wolfe;
Appeared in: Computer
Publication date: Nov 2017, volume: 50, issue:11, pages: 50 - 58
Publisher: IEEE
 
» The Mystery Curve: A Signal Processing Point of View [Lecture Notes]
Abstract:
In the first chapter of a recently published book on artful mathematics [1], a linear combination of harmonic signals called mystery curves were introduced. Although their Fourier-based analysis brings interesting results, this lecture note provides a different and important perspective, especially useful for our signal processing community. Based on polar coordinate systems and low-pass filtering approaches, the patterns of the curves can be designed by locally curve tracing instead of trial and error, including not only two-dimensional (2-D) but also three-dimensional (3-D) modeling. Concrete examples and online MATLAB codes are provided so that applications from art and logo design to amplitude modulation (AM)-frequency modulation (FM) signal analysis are realizable.
Autors: Soo-Chang Pei;Kuo-Wei Chang;
Appeared in: IEEE Signal Processing Magazine
Publication date: Nov 2017, volume: 34, issue:6, pages: 158 - 163
Publisher: IEEE
 
» The New Moneyball: How Ballpark Sensors Are Changing Baseball
Abstract:
Advancements in the capability of sensors, processors, and storage devices have led to an explosion in the amount of data that is captured during sporting events. The Statcast system, for example, uses Doppler radar and stereoscopic video from two arrays of high-resolution optical imagers to acquire seven terabytes of data during each Major League Baseball (MLB) game. One use of these data is to enhance the experience of sports fans. As a case in point, Statcast data are used to generate information and visualizations that are disseminated in real time through telecasts and other media such as an app which displays pitch parameters derived from sensor measurements.
Autors: Glenn Healey;
Appeared in: Proceedings of the IEEE
Publication date: Nov 2017, volume: 105, issue:11, pages: 1999 - 2002
Publisher: IEEE
 
» The New Science Wars
Abstract:
Science and scholarship are under attack from all sides. To a large degree the lack of appreciation is due to a fundamental misunderstanding about the nature of scientific inquiry.
Autors: Hal Berghel;
Appeared in: Computer
Publication date: Nov 2017, volume: 50, issue:11, pages: 72 - 76
Publisher: IEEE
 
» The Power of Small: The Effects of Distributed Energy Resources on System Reliability
Abstract:
It's a sunny day in Honolulu, Hawaii , and rooftop photovoltaic (PV) systems across the island are serving a significant penetration of the load. A large generator trips offline, and frequency drops quickly-to the point where a block of load is shed to restore the balance between generation and load. However, disengaging those feeders disconnects not only the load but also the PV generation on those feeders; so balance is not restored and frequency continues to drop.
Autors: Debra Lew;Marc Asano;Jens Boemer;Colton Ching;Ulrich Focken;Richard Hydzik;Matthias Lange;Amber Motley;
Appeared in: IEEE Power and Energy Magazine
Publication date: Nov 2017, volume: 15, issue:6, pages: 50 - 60
Publisher: IEEE
 
» The Rate Region for Secure Distributed Storage Systems
Abstract:
The problem of characterizing the fundamental tradeoff between storage and repair bandwidth of exact-repair regenerating codes against a passive eavesdropper is studied. The eavesdropper is assumed to be capable of observing the data stored in a fixed number of nodes and the data involved in the repair of these nodes. In this paper, the tradeoff for regenerating codes with small parameters is characterized, and then, the results are extended to some general settings.
Autors: Fangwei Ye;Kenneth W. Shum;Raymond W. Yeung;
Appeared in: IEEE Transactions on Information Theory
Publication date: Nov 2017, volume: 63, issue:11, pages: 7038 - 7051
Publisher: IEEE
 
» The Robustness of Deep Networks: A Geometrical Perspective
Abstract:
Deep neural networks have recently shown impressive classification performance on a diverse set of visual tasks. When deployed in real-world (noise-prone) environments, it is equally important that these classifiers satisfy robustness guarantees: small perturbations applied to the samples should not yield significant loss to the performance of the predictor. The goal of this article is to discuss the robustness of deep networks to a diverse set of perturbations that may affect the samples in practice, including adversarial perturbations, random noise, and geometric transformations. This article further discusses the recent works that build on the robustness analysis to provide geometric insights on the classifier's decision surface, which help in developing a better understanding of deep networks. Finally, we present recent solutions that attempt to increase the robustness of deep networks. We hope this review article will contribute to shed ding light on the open research challenges in the robustness of deep networks and stir interest in the analysis of their fundamental properties.
Autors: Alhussein Fawzi;Seyed-Mohsen Moosavi-Dezfooli;Pascal Frossard;
Appeared in: IEEE Signal Processing Magazine
Publication date: Nov 2017, volume: 34, issue:6, pages: 50 - 62
Publisher: IEEE
 
» The Role of Gender in Students’ Ratings of Teaching Quality in Computer Science and Environmental Engineering
Abstract:
Students’ ratings of teaching quality on course units in a computer science program and an environmental engineering program at a large Swedish university were obtained using the Course Experience Questionnaire; 8888 sets of ratings were obtained from men and 4280 sets were obtained from women over ten academic years. These student ratings from the two programs showed certain differences; in particular, teachers tended to receive higher ratings in subjects that were less typical for their gender than in subjects that were more typical for their gender. There were differences in the ratings given to male and female teachers, differences in the ratings given by male and female students, and interactions between these two effects. There was no systematic trend for students to give different ratings to teachers of the same gender as themselves than to teachers of the other gender. Nevertheless, without exception, even the statistically significant effects were small in magnitude and unlikely to be of theoretical or practical importance. It is concluded that the causes of differences in the career progression of male and female teachers in engineering education need to be sought elsewhere.
Autors: Linda Price;Ingrid Svensson;Jonas Borell;John T. E. Richardson;
Appeared in: IEEE Transactions on Education
Publication date: Nov 2017, volume: 60, issue:4, pages: 281 - 287
Publisher: IEEE
 
» The SMAP Level 4 Carbon Product for Monitoring Ecosystem Land–Atmosphere CO2 Exchange
Abstract:
The National Aeronautics and Space Administration’s Soil Moisture Active Passive (SMAP) mission Level 4 Carbon (L4C) product provides model estimates of the Net Ecosystem CO2 exchange (NEE) incorporating SMAP soil moisture information. The L4C product includes NEE, computed as total ecosystem respiration less gross photosynthesis, at a daily time step posted to a 9-km global grid by plant functional type. Component carbon fluxes, surface soil organic carbon stocks, underlying environmental constraints, and detailed uncertainty metrics are also included. The L4C model is driven by the SMAP Level 4 Soil Moisture data assimilation product, with additional inputs from the Goddard Earth Observing System, Version 5 weather analysis, and Moderate Resolution Imaging Spectroradiometer satellite vegetation data. The L4C data record extends from March 31, 2015 to present with ongoing production and 8–12 day latency. Comparisons against concurrent global CO2 eddy flux tower measurements, satellite solar-induced canopy florescence, and other independent observation benchmarks show favorable L4C performance and accuracy, capturing the dynamic biosphere response to recent weather anomalies. Model experiments and L4C spatiotemporal variability were analyzed to understand the independent value of soil moisture and SMAP observations relative to other sources of input information. This analysis highlights the potential for microwave observations to inform models where soil moisture strongly controls land CO2 flux variability; however, skill improvement relative to flux towers is not yet discernable within the relatively short validation period. These results indicate that SMAP provides a unique and promising capability for monitoring the linked global terrestrial water and carbon cycles.
Autors: Lucas A. Jones;John S. Kimball;Rolf H. Reichle;Nima Madani;Joe Glassy;Joe V. Ardizzone;Joe V. Ardizzone;Andreas Colliander;James Cleverly;Ankur R. Desai;Derek Eamus;Eugénie S. Euskirchen;Lindsay Hutley;Craig Macfarlane;Russell L. Scott;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Nov 2017, volume: 55, issue:11, pages: 6517 - 6532
Publisher: IEEE
 
» The State of Our Society [President's Message]
Abstract:
Presents the President's message for this issue of the publication.
Autors: Tomy Sebastian;
Appeared in: IEEE Industry Applications Magazine
Publication date: Nov 2017, volume: 23, issue:6, pages: 6 - 7
Publisher: IEEE
 
» The Stochastic Response Surface Method for Small-Signal Stability Study of Power System With Probabilistic Uncertainties in Correlated Photovoltaic and Loads
Abstract:
This paper explores applications of stochastic response surface method (SRSM) in the small-signal stability analysis of the power system with probabilistic uncertainties in correlated photovoltaic and loads. A detailed model is provided to simulate the dynamics in the PV system. SRSM is presented to approximate the critical damping ratio as a function of independent standard random variables, which are transformed from correlated loads and irradiance by Nataf transformation. Two applications of SRSM are explored, namely, estimating the probability of power system small-signal instability, and providing the emergency control when the system damping is reduced suddenly. The modified two-area four-machine system and IEEE 39-bus 10-machine standard system are used to test SRSM and its applications.
Autors: Yichen Zhou;Yonggang Li;Weidong Liu;Deshui Yu;Zhechao Li;Jiaomin Liu;
Appeared in: IEEE Transactions on Power Systems
Publication date: Nov 2017, volume: 32, issue:6, pages: 4551 - 4559
Publisher: IEEE
 
» The Study of Fe83Ga17 Films act as Magnetostrictive Actuator on PZT Substrate
Abstract:
The properties of Fe–Ga thin films on PZT substrate were investigated in this paper. In the Fe–Ga/PZT (ME) devices the Fe–Ga magnetostrictive films act as a driver, therefore it should exhibit a good magnetic and mechanical properties. During sputtering, Ar pressure was changed and Fe–Ga thin films were obtained. It is shown that there is a strong relationship between the gas pressure and film adherence, conductivity, magnetic, and mechanical properties of Fe–Ga thin films. We found that the Fe–Ga/PZT devices with high Young’s modulus and high permittivity also performance good in the ME coupling test. The ME coefficient was 0.17 V/cm Oe at resonance frequency, although the thickness of Fe–Ga film only was about 300 nm.
Autors: Jiaxing Shi;Jie Zhu;Liping Yin;Hui Jiang;Cifu Lu;Xuexu Gao;Xiaoqian Bao;Jiheng Li;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» The Therac-25: 30 Years Later
Abstract:
A widely cited 1993 Computer article described failures in a software-controlled radiation machine that massively overdosed six people in the late 1980s, resulting in serious injury and fatalities. How far have safety-critical systems come since then?
Autors: Nancy G. Leveson;
Appeared in: Computer
Publication date: Nov 2017, volume: 50, issue:11, pages: 8 - 11
Publisher: IEEE
 
» The Thickness Dependence of Soft Magnetic Properties of (FeCo)-Al Alloy Thin Films
Abstract:
A systematic study of the film-thickness dependence of soft magnetic properties and magnetization dynamics of Fe73Co25Al2 alloy thin films has been carried out. These films have columnar structures grown along the film normal, with the average width of the columns of about 30 nm. The saturation magnetization is about 1550 emu/cc, which remains nearly unchanged with film thickness over a range from 10 to 120 nm. The coercivity is found to increase with film thickness from 15 to 64 Oe over a range of 11 to about 50 nm, and then slightly decrease with further increase of thickness. The effective damping parameter measured by ferromagnetic resonance over a frequency range from 12 to 66 GHz is found to decrease with film thickness, becoming 0.0004 and 0.0006, for the films deposited onto fused silica and MgO (100) substrate, respectively.
Autors: Yusuke Ariake;Isao Kanada;Tim Mewes;Gary Mankey;Yoshitomo Tanaka;Shuang Wu;Claudia Mewes;Takao Suzuki;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» The Transition From Weak to Strong Diffuse Radar Bistatic Scattering From Rough Ocean Surface
Abstract:
Many of the currently used models of scattering from a rough ocean surface are designed for the regime of strong diffuse scattering that takes place at large Rayleigh parameter . Using them for the case of weak, or even moderate diffuse scattering that is characterized by would lead to an incorrect result. At the same time, for practical applications, it is important to describe the transition from partially coherent scattering to completely noncoherent, strong diffuse scattering in terms of the bistatic radar cross section . This situation may occur for scattering of global navigation satellite system (GNSS) signals or other signals of opportunity from a rough ocean surface under weak winds, or from ice. In this paper, we obtain an expression for for the case of weak-to-moderate diffuse scattering using a formulation based on the small slope approximation of the first order. For a reasonable range of , calculations can be quickly performed using standard desktop computers. We demonstrate results of such calculations for bistatic radar scattering for -band at low-to-moderate and its transition to at large values of .
Autors: Alexander G. Voronovich;Valery U. Zavorotny;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Nov 2017, volume: 65, issue:11, pages: 6029 - 6034
Publisher: IEEE
 
» The Underrepresentation of Women in Computing Fields: A Synthesis of Literature Using a Life Course Perspective
Abstract:
Using a life course perspective, this literature review synthesizes research on women’s underrepresentation in computing fields across four life stages: 1) pre-high school; 2) high school; 3) college major choice and persistence; and 4) post-baccalaureate employment. Issues associated with access to, and use of, computing resources at the pre-high school and high school levels are associated with gender differences in interest and attitudes toward computing. At the college level, environmental context (classroom design, interactions with peers and role models, signals from stereotypical images) contribute to whether students will major in computing, whereas psychosocial factors (e.g., sense of belonging and self-efficacy) and departmental culture play a role in persistence in computing fields. As in other fields, issues associated with work-life conflict, occupational culture, and mentoring/networking opportunities play a role in women’s participation in the computing workforce. Several initiatives and programs have been implemented to address women’s underrepresentation in computing fields. While great strides have been made in making computing more accessible, the life course perspective highlights the importance of longitudinal studies in identifying students’ pathways to and through computing fields, as well as how interventions across life stages may intersect or cumulate to generate trends in computing participation.
Autors: Joyce B. Main;Corey Schimpf;
Appeared in: IEEE Transactions on Education
Publication date: Nov 2017, volume: 60, issue:4, pages: 296 - 304
Publisher: IEEE
 
» The Virtual Trackpad: An Electromyography-Based, Wireless, Real-Time, Low-Power, Embedded Hand-Gesture-Recognition System Using an Event-Driven Artificial Neural Network
Abstract:
This brief presents a wireless, low-power embedded system that recognizes hand gestures by decoding surface electromyography (EMG) signals. Ten hand gestures used on commercial trackpads, including pinch, stretch, swipe left, swipe right, scroll up, scroll down, single click, double click, pat, and ok, can be recognized in real time. Features from four differential EMG channels are extracted in multiple time windows. Unlike traditional data segmentation methods, an event-driven method is proposed, with the gesture event detected in the hardware. Feature extraction is triggered only when an event is detected, minimizing computation, memory, and system power. A time-delayed artificial neural network (ANN) is used to predict the gesture from the transient EMG features instead of traditional steady-state features. The ANN is implemented in the microcontroller with a processing time less than 0.2 ms. The detection results are sent wirelessly to a computer. The device weights 15.2 g. A 4.6 g battery supports up to 40 h continuous operation. To our knowledge, this brief shows the first real-time, embedded hand-gesture-recognition system using only transient EMG signals. Experiments with four subjects show that the device can achieve a recognition of ten gestures with an average accuracy of 94%.
Autors: Xilin Liu;Jacob Sacks;Milin Zhang;Andrew G. Richardson;Timothy H. Lucas;Jan Van der Spiegel;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Nov 2017, volume: 64, issue:11, pages: 1257 - 1261
Publisher: IEEE
 
» The Weight Distributions of Two Classes of Nonbinary Cyclic Codes With Few Weights
Abstract:
The objective of this letter is to construct two classes of cyclic codes over with few weights, where is an odd prime. The weight distributions of these codes are determined. Some of the cyclic codes are optimal, which refers to meeting a certain bound on linear codes. The number of nonzero weights of these codes is not more than five and these codes can be employed to obtain secret sharing schemes.
Autors: Li Liu;Xianhong Xie;Lanqiang Li;Shixin Zhu;
Appeared in: IEEE Communications Letters
Publication date: Nov 2017, volume: 21, issue:11, pages: 2336 - 2339
Publisher: IEEE
 
» Theoretical Investigation on a Multifrequency Multimode Gyrotron at Ka-Band
Abstract:
In this paper, a multifrequency, multimode gyrotron has been designed, which can operate at 28, 29, 31, and 32 GHz with corresponding modes TE0.3, TE+5.2, TE−3.3, and TE+6.2, respectively. For all operating status, the mode competitions have been investigated carefully with the help of a new time-dependent, multimode, self-consistent code, which is built on the trajectory approach. For the operating at 28 GHz, it also has been simulated by CST Particle Studio. They have similar results when comparing two results. For the operating at other status, the changes of electron parameters caused by the changed dc-magnetic field have been analyzed in detail. In the analyzes, the guiding center radius and Larmor radius would not be influenced severely, but the velocity ratio would be influenced seriously, such as, the velocity ratio of operating at 32 GHz would be reduced to about 0.9787, which caused a severe reduction in the efficiency. In order to alleviate the influences, a compensation magnetic coil (CMC) has been used in the magnetron injection gun region, in which the changes of electron parameters have been analyzed too. The simulation results show that the electron efficiency of operating at 32 GHz can be increased from 24.6% to 31% by applying CMC. The multimode multifrequency gyrotron operated at ka-band gyrotron has been investigated in theory, which can provide new possibilities in high-power millimeter source development.
Autors: Qiao Liu;Yinghui Liu;Xinjian Niu;Jianhua Xu;Jianing Zhao;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Nov 2017, volume: 45, issue:11, pages: 2955 - 2961
Publisher: IEEE
 
» Thermal FMR Spectral Characterization of Very Low RA In-Plane MgO Magnetic Tunnel Junctions
Abstract:
The ability to fabricate MgO magnetic tunnel junction nanopillars with low RA and high TMR opens the door to new devices such as magnetic memories or nanooscillators. Here, we address the dynamic behavior of a CoFeB/MgO/CoFeB MTJ with a synthetic-antiferromagnetic pinned layer as a potential candidate for spin-transfer torque (STT) driven applications. The unpatterned stack presents an RA of and both free layer and barrier are patterned down to a nm2 elliptical shape. The observed high-frequency spectra displayed deviations from the uniform precession modes due to additional coupling fields. A dependence of the STT magnitude on the analyzed mode was obtained, differing from previous reports, most likely due to the very low RA employed.
Autors: Ana V. Silva;Ricardo Ferreira;Elvira Paz;Diana C. Leitao;Thibaut Devolder;Susana Cardoso;Paulo P. Freitas;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Thickness-Dependent Self-Induced Spin-Pumping in Cobalt Thin Films
Abstract:
A spin current can be produced and converted into a charge current in a single ferromagnetic material layer. Such an effect is called self-induced spin pumping. It is usually ignored in the bilayer structures. However, it is very important in application of the single layer structure. In this paper, the inverse spin Hall effect (ISHE) induced voltage in a series of single layered cobalt (Co) thin films with various thicknesses is investigated. The Co thin films are prepared by the magnetron sputtering system. The quantitative analysis of charge current density (, effective magnetization (, and damping constant ( is obtained by analyzing the ISHE and ferromagnetic resonance data. Both the charge current and damping constant are thickness-dependent. The calculated values of have a linear dependence on , consistent with the theory of spin pumping.
Autors: Yi-Chien Weng;G. Y. Luo;C. -T. Liang;J. G. Lin;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Thin Film In0.53Ga0.47As Schottky Diodes for 28.3-THz Detection
Abstract:
A thin film Au-In0.53Ga0.47As Schottky diode device has been fabricated for 28.3-THz detection. The design and structure of the diode enable dual detection modes of rectification and photodetection. A small contact area and a thin film results in a reduced capacitance and a reduced series resistance, respectively, which enable nonlinear detection, and, the thin film allows generation of hot carriers in the anode and cathode, which results in a net photocurrent by modulating the barrier heights with a dc voltage. Our experimental results show that the detected current can be explained by the superposition of the two currents, which are theoretically calculated. The maximum responsivity is approximately 0.03 A/W, a relatively high value, which is a direct result of the superposition of the currents. The device structure is achieved by a flip-bond transfer method.
Autors: Rozana Hussin;Lingjie Liu;Yi Luo;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Nov 2017, volume: 64, issue:11, pages: 4450 - 4456
Publisher: IEEE
 
» Three-Axis Capacitive Touch-Force Sensor for Clinical Breast Examination Simulators
Abstract:
Clinical breast examinations (CBEs) are a vital part of breast cancer screening programs. However, there is a lack of standardization in the kinds of motion and the forces used during the examination, which can lead to either an inaccurate or a missed diagnosis. The use of sensors in CBE simulations and training can help to alleviate this issue. This paper demonstrates a flexible, three-axis capacitive touch-force sensor that utilizes a patterned elastomeric dielectric layer. The sensor was fabricated from a copper-clad Kapton laminate and can resolve normal pressure and track directional motion. The electronic and mechanical properties of the patterned dielectric layer were analyzed in detail using finite-element analysis techniques and these results were then used to optimize the sensor. In a mock CBE setup, we used a breast model to demonstrate that the sensor, when placed under the model, could track a normal force of about 18 N when applied to the test area, as well as the trajectory of the force as it was applied around the breast model. This data, along with the accompanying variations in signal patterns, can be utilized to quantify the CBE conducted by an expert physician, which in turn can be used as feedback in training tools for residents and other physicians.
Autors: Jayer Fernandes;Hongrui Jiang;
Appeared in: IEEE Sensors Journal
Publication date: Nov 2017, volume: 17, issue:22, pages: 7231 - 7238
Publisher: IEEE
 
» Three-Dimensional Deformation Retrieval in Geosynchronous SAR by Multiple-Aperture Interferometry Processing: Theory and Performance Analysis
Abstract:
The 3-D deformation retrieval is significant for the accurate evaluation of geologic disasters (e.g., earthquakes and landslides). Multiple-aperture interferometry (MAI) is an effective method to obtain 3-D deformation, combined with the cross-heading tracks synthetic aperture radar (SAR) data. However, because of the limitations of the low earth orbit SAR, a long satellite revisit time, small common areas of the cross-heading tracks data, and the unsatisfied along-track deformation measurement accuracy usually exist in the traditional MAI 3-D deformation retrieval. Geosynchronous SAR (GEO SAR) runs in the geosynchronous orbit, which has the advantages of a large observation area and a short revisit time. This paper focuses on 3-D deformation retrieval by GEO SAR MAI processing. Aiming at the high orbit and the squint looking of GEO SAR, the accurate expressions of the along-track deformation, 3-D deformation, and the errors in GEO SAR MAI processing are given. The distortions and their correction in the MAI interferogram brought by the geometrical difference between the forward- and backward-looking interferograms and the multicycles flat-earth and topographic phases are given. Moreover, an optimal subaperture selection method based on minimum position dilution of precision is proposed. Finally, the effectiveness of the proposed method is validated by simulations and the experiment of BeiDou-2 inclined geosynchronous orbit navigation satellite. The theoretical analysis and the experimental results suggest centimeter-level and even millimeter-level deformation measurement accuracy could be obtained in 3-D by GEO SAR MAI processing.
Autors: Cheng Hu;Yuanhao Li;Xichao Dong;Rui Wang;Chang Cui;Bin Zhang;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Nov 2017, volume: 55, issue:11, pages: 6150 - 6169
Publisher: IEEE
 
» Three-Site Diversity at Ka-Band Satellite Links in Norway: Gain, Fade Duration, and the Impact of Switching Schemes
Abstract:
Analysis of two years of measurements from a three-site satellite beacon diversity experiment in Norway is presented. The operating frequency was 19.68 GHz, elevation angles were between 21.7° and 22°, and site separations 23, 29.7, and 50.1 km. Due to the spatial decorrelation of rain, simultaneous attenuation at all sites occurs much less frequently than at a single site. All three two-site diversity combinations and a three-site diversity combination were investigated. Measured values for diversity gain at 0.01% exceedance level were 8.8, 10.7, and 12.1 dB for the two-site pairs and 12.5 dB for three sites, given a single-site attenuation level between 13 and 16 dB. Comparison of the measured data showed excellent agreement with the current ITU-R model. Fade duration statistics for single site and for the combinations are analyzed, and it is shown that the statistics for the diversity combinations can be modeled using a double-lognormal function as is the case for single-site statistics. Analysis of the effects of a nonperfect switch-over scheme showed that using moderate switch-over threshold levels and time delays, the number of switchovers can be significantly reduced while most of the diversity gain and reduction in number of fades are retained.
Autors: Martin Rytir;Michael Cheffena;Per Arne Grotthing;Lars E. Bråten;Terje Tjelta;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Nov 2017, volume: 65, issue:11, pages: 5992 - 6001
Publisher: IEEE
 
» Threshold Voltage Statistical Variability and Its Sensitivity to Critical Geometrical Parameters in Ultrascaled InGaAs and Silicon FETs
Abstract:
We investigate the statistical variability of the threshold voltage and its sensitivity to critical geometrical parameters in ultrascaled In0.53Ga0.47As and Si MOSFETs by means of 3-D quantum-corrected drift-diffusion simulations. Dual-gate ultrathin-body and FinFET device structures are analyzed for both channel materials. To assess the variability and sensitivity effects also from the scaling perspective, we consider devices belonging to two technological nodes with gate lengths 15 and 10.4 nm, designed according to International Technology Roadmap for Semiconductors (ITRS) specifications. Variability sources included in our analysis are random-dopant fluctuation, work-function fluctuation (WFF), as well as body- and gate-line-edge roughness (LER). Sensitivity to critical geometrical parameters is assessed by varying gate length, channel thickness, and oxide thickness. Results point out the major detrimental effect of WFF and Body-LER for InGaAs FETs, whereas WFF dominates in Si counterparts. Moreover, the sensitivity analysis shows that control over gate length and channel thickness in the InGaAs technology is fundamental in order to keep variability within tolerable values. Scaling of the InGaAs technology highlights the importance of abiding to ITRS projections regarding LER control improvement. Furthermore, a tight channel thickness control is required in ultrascaled devices due to the large sensitivity of the threshold voltage to the channel thickness combined with increased variability.
Autors: Nicolò Zagni;Francesco Maria Puglisi;Giovanni Verzellesi;Paolo Pavan;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Nov 2017, volume: 64, issue:11, pages: 4607 - 4614
Publisher: IEEE
 
» Throughput of Infrastructure-Based Cooperative Vehicular Networks
Abstract:
In this paper, we provide the detailed analysis of the achievable throughput of infrastructure-based vehicular network with a finite traffic density under a cooperative communication strategy, which explores the combined use of vehicle-to-infrastructure (V2I) communications, vehicle-to-vehicle (V2V) communications, the mobility of vehicles, and cooperations among vehicles and infrastructure to facilitate the data transmission. A closed form expression of the achievable throughput is obtained, which reveals the relationship between the achievable throughput and its major performance-impacting parameters, such as distance between adjacent infrastructure points, the radio ranges of infrastructure and vehicles, the transmission rates of V2I and V2V communications, and vehicular density. Numerical and simulation results show that the proposed cooperative communication strategy significantly increases the throughput of vehicular networks, compared with its non-cooperative counterpart, even when the traffic density is low. Our results shed insight on the optimum deployment of vehicular network infrastructure and the optimum design of cooperative communication strategies in vehicular networks to maximize the throughput.
Autors: Jieqiong Chen;Guoqiang Mao;Changle Li;Ammar Zafar;Albert Y. Zomaya;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: Nov 2017, volume: 18, issue:11, pages: 2964 - 2979
Publisher: IEEE
 
» Time behavior of partial discharges and life of type II turn insulation specimens under repetitive impulse and sinusoidal waveforms
Abstract:
Rotating machines controlled by power electronics are becoming more-and-more common in medium voltage assets, including renewable generation and industrial plants. The design of rotating machine bar insulation under AC sinusoidal waveform is well understood, but the peculiarities of the overvoltage, electric field distribution, and partial discharge (PD) experienced by the insulation when fed by a pulse width modulator (PWM) require new testing procedures, and the International Electrotechnical Commission (IEC) is now involved in the standardization [1]- [10]. The purpose is to provide adjustable speed drives and, in general, rotating machines controlled by power electronics, having the same level of reliability as conventional, power supplied, machines, which may not be the case at the present time.
Autors: Gian Carlo Montanari;
Appeared in: IEEE Electrical Insulation Magazine
Publication date: Nov 2017, volume: 33, issue:6, pages: 17 - 26
Publisher: IEEE
 

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