Electrical and Electronics Engineering publications abstract of: 10-2017 sorted by title, page: 18

» Ultraprecise Three-Axis Visual Motion Tracking of Microscopic Objects
Abstract:
Real-time image processing algorithms and associated mathematical formulas that render ultraprecise three-axis visual motion tracking are presented. The principle of three-axis motion tracking is based on lateral sampled white light interferometry (LSWLI) and real-time unbiased image registration. Two distinct regions of interest (ROIs), i.e., in-plane ROI and out-of-plane ROI, in a single 2-D image, taken at a single time instant, are processed in real time. Real-time continuous image registration (CIR) is realized and applied to 2-D shadow projection image content of the object to locate the object’s in-plane position, whereas adaptive 1-D CIR (A1-CIR) is proposed and applied to an LSWLI fringe pattern on the object to determine its out-of-plane position. Processing of images is synchronized with real-time image acquisition to realize three-axis motion tracking. Computer simulations are used to demonstrate bias caused by image registration and to examine its effect on measurement precision. The ability of the proposed approach to eliminate measurement bias is validated. Experimental results are presented and used to examine measurement resolution for positioning and to illustrate measurement precision for long-range motion tracking.
Autors: Peng Cheng;Chia-Hsiang Menq;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Oct 2017, volume: 66, issue:10, pages: 2597 - 2605
Publisher: IEEE
 
» Ultrasmall Mode Volumes of Multilayered Hyperbolic Metamaterial Nanocavities in the Visible Range
Abstract:
Designing optical nanocavities with high quality factors (Q) or small mode volume (Vm) has important applications in the field of quantum information due to the strong light-matter coupling phenomena. The multilayered hyperbolic metamaterial (HMM) nanocavities have been designed and numerically investigated to achieve the small mode volume. Unique dispersion relations of our HMM nanocavity enable propagation of large wave vectors result in strong wave confinement. The excitation of coupled localized surface plasmons, which have achieved ultrasmall mode volume below 10 –6 λ3 or high Q/Vm around 10λ–3 causing better electric fields confinement. These properties can be demonstrated by rationally the geometrical parameters and may have potential applications in light-matter interaction.
Autors: Song Yang;Jianhua Yang;Xiaokang Song;Yuanqi Huang;Li Yu;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 9
Publisher: IEEE
 
» Ultrasound Aided Vertebral Level Localization for Lumbar Surgery
Abstract:
Localization of the correct vertebral level for surgical entry during lumbar hernia surgery is not straightforward. In this paper, we develop and evaluate a solution using free-hand 2-D ultrasound (US) imaging in the operation room (OR). Our system exploits the difference in spinous process shapes of the vertebrae. The spinous processes are pre-operatively outlined and labeled in a lateral lumbar X-ray of the patient. Then, in the OR the spinous processes are imaged with 2-D sagittal US, and are automatically segmented and registered with the X-ray shapes. After a small number of scanned vertebrae, the system robustly matches the shapes, and propagates the X-ray label to the US images. The main contributions of our work are: we propose a deep convolutional neural network-based bone segmentation algorithm from US imaging that outperforms state of the art methods in both performance and speed. We present a matching strategy that determines the levels of the spinal processes being imaged. And lastly, we evaluate the complete procedure on 19 clinical data sets from two hospitals, and two observers. The final labeling was correct in 92% of the cases, demonstrating the feasibility of US-based surgical entry point detection for spinal surgeries.
Autors: Nora Baka;Sieger Leenstra;Theo van Walsum;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Oct 2017, volume: 36, issue:10, pages: 2138 - 2147
Publisher: IEEE
 
» Unbiased Minimum Variance Fault and State Estimation for Linear Discrete Time-Varying Two-Dimensional Systems
Abstract:
The fault and state estimation problem is addressed for a class of linear discrete time-varying two-dimensional systems subject to state and measurement noises. Two estimators are proposed to compute the estimation of the system state and/or fault recursively, both of which are unbiased with minimum variance. Through formulating the estimation problem as the solvability problem of the corresponding matrix equations of estimator gains and system constraint, the necessary and sufficient condition of the existence and the solution for the proposed estimators are given. An example is used to demonstrate the effectiveness of the proposed estimators.
Autors: Youqing Wang;Dong Zhao;Yueyang Li;Steven X. Ding;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Oct 2017, volume: 62, issue:10, pages: 5463 - 5469
Publisher: IEEE
 
» Uncertainty Management in Lebesgue-Sampling-Based Diagnosis and Prognosis for Lithium-Ion Battery
Abstract:
Lebesgue-sampling-based fault diagnosis and prognosis (LS-FDP) is developed with the advantage of less computation requirement and smaller uncertainty accumulation. Same as other diagnostic and prognostic approaches, the accuracy and precision of LS-FDP are significantly influenced by the parameters and uncertainties in the diagnostic and prognostic models. To improve performance of LS-FDP, this paper introduces an online model parameter adaptation scheme, which is realized by a recursive least square method with a forgetting factor. In addition, uncertainty of remaining useful life (RUL) prediction is managed by adjusting the model noises through a short-term prediction and correction loop. To verify the proposed parameter adaptation and noise adjustment methods, they are designed and implemented in a particle-filtering-based LS-FDP algorithm with applications to Li-ion batteries. Experimental results show that the proposed approach has significant improvement on both battery capacity estimation and RUL prediction.
Autors: Wuzhao Yan;Bin Zhang;Guangquang Zhao;John Weddington;Guangxing Niu;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Oct 2017, volume: 64, issue:10, pages: 8158 - 8166
Publisher: IEEE
 
» Unconditionally Stable Non-Foster Element Using Active Transversal-Filter-Based Negative Group Delay Circuit
Abstract:
This letter introduces a novel type of non-Foster element using a microwave transversal-filter-based negative group delay (NGD) circuit that can exhibit unconditional stability. The proposed device is realized by a distributed amplifier, in which the NGD response is synthesized by adjusting the ratio of transconductance of transistors in each stage. On top of this, by properly amending the in-band magnitude and phase characteristics, the NGD circuit can realize non-Foster elements within the operating band. Furthermore, thanks to the distributed topology, the proposed network has very good input and output matching characteristics. As proof-of-concept, a prototype of the proposed non-Foster element is built to validate the proposed scheme. The experimental results show that the proposed circuit can realize a unilateral non-Foster element composed of a −1 pF shunt capacitor and a −1.25 nH series inductor.
Autors: Tiedi Zhang;Ruimin Xu;Chung-Tse Michael Wu;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Oct 2017, volume: 27, issue:10, pages: 921 - 923
Publisher: IEEE
 
» Unconstrained Diameters for Deep Coalescence
Abstract:
The minimizing-deep-coalescence (MDC) approach infers a median (species) tree for a given set of gene trees under the deep coalescence cost. This cost accounts for the minimum number of deep coalescences needed to reconcile a gene tree with a species tree where the leaf-genes are mapped to the leaf-species through a function called leaf labeling. In order to better understand the MDC approach we investigate here the diameter of a gene tree, which is an important property of the deep coalescence cost. This diameter is the maximal deep coalescence costs for a given gene tree under all leaf labelings for each possible species tree topology. While we prove that this diameter is generally infinite, this result relies on the diameter’s unrealistic assumption that species trees can be of infinite size. Providing a more practical definition, we introduce a natural extension of the gene tree diameter that constrains the species tree size by a given constant. For this new diameter, we describe an exact formula, present a complete classification of the trees yielding this diameter, derive formulas for its mean and variance, and demonstrate its ability using comparative studies.
Autors: Paweł Górecki;Jarosław Paszek;Oliver Eulenstein;
Appeared in: IEEE/ACM Transactions on Computational Biology and Bioinformatics
Publication date: Oct 2017, volume: 14, issue:5, pages: 1002 - 1012
Publisher: IEEE
 
» Underapproximating Backward Reachable Sets by Semialgebraic Sets
Abstract:
Underapproximations (UAs) of backward reachable sets play an important role in controller synthesis and trajectory analysis for constrained nonlinear dynamical systems, but there are few methods available to compute them. Given a nonlinear system, a target region of simply connected compact type and a time duration, we present a method using boundary analysis to compute an UA of the backward reachable set. The UA is represented as a semialgebraic set, formed by what we term polynomial functions. The polynomial function is a semidefinite positive function with one real root, such that the interior and closure of a semialgebraic set formed by it are both simply connected and have the same boundary. The function can be computed by solving a convex program, which is constructed based on sum-of-squares decomposition and linear interval inequalities. We test our method on several examples and compare them with existing methods. The results show that our method can obtain better estimations more efficiently in terms of time for these special examples.
Autors: Bai Xue;Zhikun She;Arvind Easwaran;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Oct 2017, volume: 62, issue:10, pages: 5185 - 5197
Publisher: IEEE
 
» Underwater Acoustic Carrier Aggregation: Achievable Rate and Energy-Efficiency Evaluation
Abstract:
In this work, carrier aggregation in orthogonal frequency division multiplexing (OFDM)-based underwater acoustic cellular networks is proposed, and its achievable communication rate and energy efficiency are evaluated. This technique improves the total throughput of OFDM using an expanded bandwidth, where multiple carriers are aggregated for data transmission from one transmitter. In this paper, a study is presented for a practical communication system consisting of a surface buoy station mounting single transducer and an autonomous underwater vehicle also with single transducer. The results are evaluated in a simulation environment as well as by field experiments. The simulation is first performed on a wide bandwidth up to , where the results indicate that carrier aggregation can greatly improve the achievable underwater communication rate for distances up to . It is further found by simulation that the maximum bandwidth configuration does not achieve the optimal energy efficiency; instead, there is an optimal bandwidth that can lead to such optimal energy efficiency. Further measurement results obtained in sea trials with a specifically designed sounding sequence are then presented. The achievable rate and energy efficiency are evaluated by the field measurement data. The measurement results provide insights into the performance of the system under narrow bandwidth settings.
Autors: Xueyuan Zhao;Dario Pompili;João Alves;
Appeared in: IEEE Journal of Oceanic Engineering
Publication date: Oct 2017, volume: 42, issue:4, pages: 1035 - 1048
Publisher: IEEE
 
» Underwater Active Electrosense: A Scattering Formulation and its Application
Abstract:
Underwater sensing using electric field has been traditionally modeled by the computationally heavy finite element method (FEM) or boundary element method. In this paper, techniques in light scattering problems were for the first time expanded to underwater active electrosense. Numerical solutions of the volume integral equation were formulated, including a method of moment and discrete dipole approximation (DDA). We found that only DDA was suitable for conductive mediums and the connection between DDA, and a well-known sphere perturbation formula was further established. DDA was found to perform more than 100 times faster than FEM with only a 10% relative difference in underwater electrosense problems. A DDA-based unscented Kalman filter was proposed for inferring object size and location, and a one-dimensional sensor was made for further experimental validation. This paper lays a solid foundation for real-world underwater electrosensors.
Autors: Ke Wang;Khac Duc Do;Lei Cui;
Appeared in: IEEE Transactions on Robotics
Publication date: Oct 2017, volume: 33, issue:5, pages: 1233 - 1241
Publisher: IEEE
 
» Unevenly Sampled Dynamic Data Modeling and Monitoring With an Industrial Application
Abstract:
In this paper, a dynamic modeling method for unevenly sampled data is proposed for the monitoring of bi-layer (i.e., a process layer and a quality layer) dynamic processes. First, a novel uneven data dynamic canonical correlation analysis method with an integrated dynamic time window is proposed for interlayer latent structure modeling, which captures the dynamic relations between regularly sampled process data and quality data with slow and irregular sampling. The new model is a step toward big data modeling to deal with data irregularity and diversity. Second, after extracting covariations using an interlayer model, intralayer variations are extracted using subsequent principal component analysis on the residual subspaces of the original process data and quality data, respectively. Third, a concurrent monitoring method for unevenly sampled bi-layer data is proposed. Finally, the proposed method is demonstrated using an illustrative simulation example and applied successfully to a real blast furnace iron-making process.
Autors: Qiang Liu;S. Joe Qin;Tianyou Chai;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Oct 2017, volume: 13, issue:5, pages: 2203 - 2213
Publisher: IEEE
 
» Uno Lamm: The Father of HVdc Transmission [History]
Abstract:
In the early 1920s, August Uno Lamm had a vision that would ultimately take decades to come to fruition and change the world forever. Lamm, who is widely referred to as the father of high-voltage (HV) dc transmission, invented the first economical way to convert ac to dc and then back again. His discovery and development of the HV mercury-arc ionic valve paved the way for efficient and practical HV transmission.
Autors: Matthew Korytowski;
Appeared in: IEEE Power and Energy Magazine
Publication date: Oct 2017, volume: 15, issue:5, pages: 92 - 102
Publisher: IEEE
 
» Unsupervised Single and Multiple Views Feature Extraction with Structured Graph
Abstract:
Many feature extraction methods reduce the dimensionality of data based on the input graph matrix. The graph construction which reflects relationships among raw data points is crucial to the quality of resulting low-dimensional representations. To improve the quality of graph and make it more suitable for feature extraction tasks, we incorporate a new graph learning mechanism into feature extraction and add an interaction between the learned graph and the low-dimensional representations. Based on this learning mechanism, we propose a novel framework, termed as unsupervised single view feature extraction with structured graph (FESG), which learns both a transformation matrix and an ideal structured graph containing the clustering information. Moreover, we propose a novel way to extend FESG framework for multi-view learning tasks. The extension is named as unsupervised multiple views feature extraction with structured graph (MFESG), which learns an optimal weight for each view automatically without requiring an additional parameter. To show the effectiveness of the framework, we design two concrete formulations within FESG and MFESG, together with two efficient solving algorithms. Promising experimental results on plenty of real-world datasets have validated the effectiveness of our proposed algorithms.
Autors: Wenzhang Zhuge;Feiping Nie;Chenping Hou;Dongyun Yi;
Appeared in: IEEE Transactions on Knowledge and Data Engineering
Publication date: Oct 2017, volume: 29, issue:10, pages: 2347 - 2359
Publisher: IEEE
 
» Unsupervised Technique for Automatic Selection of Performance Indicators in Self-Organizing Networks
Abstract:
Self-organizing networks (SONs) aim at automating the management of cellular networks. However, tasks, such as the selection of the most appropriate performance indicators for SON functions, are still carried out by experts. In this letter, an unsupervised and autonomous technique for the selection of the most useful performance indicators is proposed, consisting in a data clustering stage followed by a supervised procedure for feature selection. Results show that the proposed method effectively relieves and outperforms an expert’s selection, allowing a drastic reduction of the volume and complexity of both network databases and SON procedures without human intervention.
Autors: David Palacios;Raquel Barco;
Appeared in: IEEE Communications Letters
Publication date: Oct 2017, volume: 21, issue:10, pages: 2198 - 2201
Publisher: IEEE
 
» User Association With Maximizing Weighted Sum Energy Efficiency for Massive MIMO-Enabled Heterogeneous Cellular Networks
Abstract:
In this letter, we design an association strategy to maximize the weighted sum energy efficiency (EE) for massive multiple-input and multiple-output (MIMO)-enabled heterogeneous cellular networks. Considering that the final formulated problem is in a sum-of-ratio form, we first need to transform it into a parametric nonfractional form, by which we can achieve its solution through a two-layer iterative algorithm. The outer layer searches the EE parameters and the multipliers associated with signal-interference-plus-noise ratio constraints using Newton-like method, and the inner layer optimizes the association indices using Lagrange multiplier method. Then, we give some convergence and complexity analyses for the proposed algorithm. Numerical results show that the proposed scheme significantly outperforms the existing one on the system throughput and network EE under a certain condition. In addition, we also investigate the impacts of the number of massive antennas and the transmit power of each pico base station on the association performance.
Autors: Tianqing Zhou;Zunxiong Liu;Dong Qin;Nan Jiang;Chunguo Li;
Appeared in: IEEE Communications Letters
Publication date: Oct 2017, volume: 21, issue:10, pages: 2250 - 2253
Publisher: IEEE
 
» User Pairing Stability in D2D-Relay Networks
Abstract:
The device-to-device (D2D)-relay mechanism, which works by integrating D2D communications with relay technology, is promising in the future networks. The user pairing is critical to the D2D-relay networks because well-designed user pairing can remarkably promote the system performance. However, most of the existing studies about user pairing mainly focus on the system performance, while the pairing stability, which indicates whether the user pairing is stable and acceptable to users, has not been comprehensively studied. In this letter, we analyze the pairing stability in the D2D-relay networks and propose a metric to quantize it. We also reveal the positive correlation between the proposed metric and the system performance. The numerical results conform to our derivations and show that by keeping the stability metric no less than a threshold, the system performance can reach the expected promotion scale.
Autors: Yu Zeng;Honglin Hu;Tianheng Xu;Boqi Jia;
Appeared in: IEEE Communications Letters
Publication date: Oct 2017, volume: 21, issue:10, pages: 2278 - 2281
Publisher: IEEE
 
» Using Laminated Metal Foam as the Top-Side Contact of a PCB-Embedded Power Die
Abstract:
The proposed innovative manufacturing process—described in detail—uses metal foam to create a pressed contact between the top side of a printed circuit board-embedded power die and the rest of the circuit. Initial prototypes were constructed using diodes with die dimensions of 4 mm 6.35 mm. The prototypes were electrically characterized: the chip and contact dc and ac impedance values were measured and compared with those obtained for conventional packaging that uses bond wires. The electrical impedance of the prototypes was found to be similar to that of a state-of-the-art industrial package. Moreover, the proposed process is simple and cost-effective. Although the results presented in this letter are promising, further research is necessary to fully assess the benefits and limitations of the process.
Autors: Yoann Pascal;Amar Abdedaim;Denis Labrousse;Mickaël Petit;Stéphane Lefebvre;François Costa;
Appeared in: IEEE Electron Device Letters
Publication date: Oct 2017, volume: 38, issue:10, pages: 1453 - 1456
Publisher: IEEE
 
» Using Pyrotechnic Current-Limiting Devices: A Case Study of What Went Right
Abstract:
The trend toward electrical rather than mechanical drivers for offshore installation has led to the implementation of large electrical systems and power generation. Due to the offshore environment constraints, such as weight and footprint limitations, most of the installation remains operated at voltages of 13.8 kV and lower, which leads to specific constraints on the electrical network design. This article provides an overview of the implementation of pyrotechnic current-limiting devices from the design stage through precommissioning, commissioning, and operation.
Autors: Terence Hazel;Jacques Lavaud;Bruno Leforgeais;
Appeared in: IEEE Industry Applications Magazine
Publication date: Oct 2017, volume: 23, issue:5, pages: 50 - 59
Publisher: IEEE
 
» Using Volt-Second Sensing to Directly Improve Torque Accuracy and Self-Sensing at Low Speeds
Abstract:
As a result of dead-time, device on-state voltage drop, dc bus voltage measurement error, etc., volt-second errors degrade precise control of torque and flux linkage, particularly at low speeds. This is true for deadbeat-direct torque and flux control, which directly manipulates the volt-second vector sourced by inverters, as well as for indirect field oriented control drives. This paper introduces a real-time sensing scheme to measure the motor terminal volt-second vectors for each switching period with negligible phase lag. Based on the volt-second sensing, a model reference adaptive system-based approach is developed to decouple the volt-second errors from inverter nonlinearity, and dc bus voltage fluctuation and measurement error. By delivering an accurate volt-second vector for each switching period, torque and flux control accuracy, self-sensing performance, and parameter estimation accuracy are significantly enhanced.
Autors: Yukai Wang;Yang Xu;Naoto Niimura;Benjamin D. Rudolph;Robert D. Lorenz;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Oct 2017, volume: 53, issue:5, pages: 4472 - 4482
Publisher: IEEE
 
» Utility Direct Interfaced Charger/Discharger Employing Unified Voltage Balance Control for Cascaded H-Bridge Units and Decentralized Control for CF-DAB Modules
Abstract:
A bidirectional high-frequency isolated ac-dc converter for utility direct interfaced electric vehicle charger with vehicle-to-grid (V2G) capability is presented in this paper. This type of charger can achieve the direct utility interface with medium voltage input. It is composed of multilevel cascaded H-bridge ac-dc converter as the first stage and modular current-fed dual active bridge dc-dc converters as the second stage. For the cascaded H-bridge converter, a unified control to balance the cascaded H-bridge dc voltages is proposed for both charging and discharging modes. For the second dc-dc isolation stage, the current-fed dual active bridge converter is used in facing of the wide conversion gain in battery charging application and also to reduce the charging current ripple. Meanwhile, to improve the system flexibility and reliability, decentralized control is utilized for individual current-fed dual active bridge converters in view of the battery charging profile. The proposed method along with the presented topology can achieve voltage balance in spite of the power flow direction, simplification of the controller for the dc-dc modules and can also bear unbalanced power flow. The simulation and experimental results have been presented to show the effectiveness of the proposed control.
Autors: Deshang Sha;Guo Xu;Yaxiong Xu;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Oct 2017, volume: 64, issue:10, pages: 7831 - 7841
Publisher: IEEE
 
» Variable Bandwidth Weighting for Texture Copy Artifact Suppression in Guided Depth Upsampling
Abstract:
In this paper, we mathematically analyze one of the most challenging issues in color image-guided depth upsampling: the texture copy artifacts. The optimal guidance weights denoted by balanced weights are proposed to best suppress texture copy artifacts. To both suppress texture copy artifacts and preserve depth discontinuities, a new general weighting scheme called variable bandwidth weighting is proposed. The variable bandwidth weighting scheme is able to adjust guidance weights according to the local depth smoothness. A new concept called relative smoothness is proposed for measuring the local depth smoothness. Given this quantitative smoothness measurement, the proposed weighting scheme can adaptively adjust the bandwidth for calculating the guidance weights in the existing methods. As we use the computationally efficient balanced weights instead of the guidance weights of a large bandwidth, the proposed method can speed up the upsampling process for about when compared with the original upsampling methods. Experimental results show the effectiveness and efficiency of the proposed method in suppressing texture copy artifacts, preserving the depth discontinuities and reducing the computational cost at the same time.
Autors: Wei Liu;Xiaogang Chen;Jie Yang;Qiang Wu;
Appeared in: IEEE Transactions on Circuits and Systems for Video Technology
Publication date: Oct 2017, volume: 27, issue:10, pages: 2072 - 2085
Publisher: IEEE
 
» Variable Flux Permanent Magnet Synchronous Machine (VF-PMSM) Design Methodologies to Meet Electric Vehicle Traction Requirements with Reduced Losses
Abstract:
Variable flux permanent magnet synchronous machines (VF-PMSMs) in which the magnetization state of low coercive force permanent magnets can be actively controlled to reduce losses in applications that require wide-speed operation have been proposed recently. While prior focus has been on achieving magnetization state manipulation without oversizing the inverter and obtaining higher torque capability, this paper extends the design objectives to include the power requirements of an electric vehicle traction motor over its entire speed range. Finite-element methods are used to study the effect of combinations of low coercive-force and high coercive-force permanent magnets arranged in either series or parallel on the performance of VF-PMSMs. While both configurations help improve the torque density, only the series configuration can help improve the high speed power capability. Experimental results showing the variable magnetization state property, torque-speed capability, and loss reduction capability of a series magnet configuration VF-PMSM test machine are presented.
Autors: Apoorva Athavale;Kensuke Sasaki;Brent S. Gagas;Takashi Kato;Robert D. Lorenz;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Oct 2017, volume: 53, issue:5, pages: 4318 - 4326
Publisher: IEEE
 
» Variable-Length Non-Overlapping Codes
Abstract:
We define a variable-length code having the property that no (non-empty) prefix of each its codeword is a suffix of any other one, and vice versa. This kind of code can be seen as an extension of two well-known codes in the literature, called, respectively, fix-free code and non-overlapping code. In this paper we present constructive algorithms for such codes and some numerical results about their cardinality.
Autors: Stefano Bilotta;
Appeared in: IEEE Transactions on Information Theory
Publication date: Oct 2017, volume: 63, issue:10, pages: 6530 - 6537
Publisher: IEEE
 
» Variation-Aware Reliable Many-Core System Design by Exploiting Inherent Core Redundancy
Abstract:
Reliability issues are more severe in multi/many-core systems because of the integration of more devices in advanced technology nodes. To achieve robust computing in nanoscale designs, many circuit-level and architecture-level redundancy techniques had been proposed, which pose large fixed silicon area overhead and a lack of flexibility. In recent years, some methods have exploited the “inherent core redundancy” of many-core systems to implicitly implement N-modular redundant (NMR) subsystems to achieve area-efficient fault-tolerant computing. However, while facing the different levels of soft error rate, task vulnerability, and task significance in the many-core system, existing core-level redundancy methods become ineffective. To achieve robust computation in many-core systems with intercore variations and mixed workloads, we propose a variation-aware core-level redundancy scheme. Two novel approaches are presented in this scheme: 1) we construct NMR tables that store the degree of redundancy using mathematical models for systems affected by these variations and 2) we dynamically allocate each replicated task to a proper core with variation-aware mapping algorithms to achieve high reliability. Based on a modified multicore simulator, Sniper-Transient Error Process Variation (TEVR), the experimental results show that the proposed scheme can increase the reliability by 47.92% and achieve the energy saving of 39% compared with conventional core-level redundancy methods.
Autors: Huai-Ting Li;Ching-Yao Chou;Yuan-Ting Hsieh;Wei-Ching Chu;An-Yeu Wu;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Oct 2017, volume: 25, issue:10, pages: 2803 - 2816
Publisher: IEEE
 
» Variational Inference-Based Positioning with Nondeterministic Measurement Accuracies and Reference Location Errors
Abstract:
Cooperative network localization plays an important role in wireless sensor network (WSN), wherein neighboring sensor nodes will help each other to calibrate their locations. However, due to the dynamic wireless propagation environment and different surroundings, the measurement accuracy at different network nodes is different and varies overtime. In this paper, the uncertainties in both measurement accuracy and reference node locations are considered to account for the impact of different surrounding environments and the initial node location errors on the cooperative network localization. A mean-field variational inference-based positioning (VIP) algorithm is proposed for cooperative network localization. The mechanism of the proposed VIP algorithm, the convergence properties, implementation complexity, and the parallel implementation structure are presented to show that the VIP algorithm provides an effective mechanism to incorporate and share the localization information among all network nodes for an improved localization performance. Finally, a concise Cramer-Rao lower bound (CRLB) is derived to reveal the principle of localization error propagation. It is disclosed that the localization error propagation principle is similar to the Ohm's Law in circuit theory, which provides a new insight into the impact of the measurement accuracy, the reference node location errors and the number of reference nodes on the cooperative network localization performance.
Autors: Bingpeng Zhou;Qingchun Chen;Henk Wymeersch;Pei Xiao;Lian Zhao;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: Oct 2017, volume: 16, issue:10, pages: 2955 - 2969
Publisher: IEEE
 
» Very high spatial resolution space charge measurement using electro-acoustic reflectometry (EAR)
Abstract:
Among the materials that find various applications in today's science and industry are insulating or dielectric materials. In electronics and electrical engineering they are used mainly as insulators in components such as capacitors and transistors. Mechanical, thermal, and dielectric properties must be taken into consideration when choosing a dielectric material for a specific use. One of the most important properties of a dielectric material is its breakdown electric field, which is the strongest electric field that can be supported by the material. When a dielectric material is put under electric stress, electric charges can be injected into it from the electrodes, and trapped in the interior. These charges can accumulate over time, generating an internal electrical field, which adds to the applied electric field and may weaken the dielectric strength of the material [1]. This effect is particularly disturbing in the context of biasing transistors, because it gives rise to a bias threshold varying with time.
Autors: L. Hamidouche;E. Geron;S. Hole;
Appeared in: IEEE Electrical Insulation Magazine
Publication date: Oct 2017, volume: 33, issue:5, pages: 9 - 16
Publisher: IEEE
 
» Vibration and Magnetic Field Sensing Using a Long-Period Grating
Abstract:
A long-period grating (LPG) written on a standard single mode fiber is investigated as a fiber optic sensor for vibration and magnetic field sensing. It is demonstrated the high sensitivity of the device to applied curvature and the possibility to monitor vibration in a wide range of frequencies from 30 Hz to 2000 Hz. The system was tested using intensity-based interrogation scheme, providing a frequency discrimination of 913 mHz. The goal of these tests was to evaluate the sensor as a passive vibration monitor in the detection of changes in resonant vibration frequencies of support infrastructures can provide information on its degradation. Furthermore, taking advantage of the intrinsic sensitivity to micro strain, alternating magnetic fields were also measured using an intensity-based interrogation scheme by coupling a Terfenol-D magnetostrictive rod to a pre-strained LPG sensor, providing a resolution below 5.61 Hz from 1.22 mTrms up to 2.53 mTrms.
Autors: Ivo M. Nascimento;Giancarlo Chesini;José Manuel Baptista;Cristiano M. B. Cordeiro;Pedro A. S. Jorge;
Appeared in: IEEE Sensors Journal
Publication date: Oct 2017, volume: 17, issue:20, pages: 6615 - 6621
Publisher: IEEE
 
» Video Encoder Architecture for Low-Delay Live-Streaming Events
Abstract:
Video-streaming events such as virtual classrooms and video conferences require a low delay between sender and receiver. In order to achieve this requirement, and to make full use of the bandwidth capacity of each receiver, each client can be provided with a personalized bitstream of which the bit rate is continuously adapted to his current network bandwidth capacity. However, such an approach requires an excessive amount of computationally complex video encoders. Therefore, this paper proposes an architecture based on coding information calculation (CIC) modules and residual encoder (RE) modules. The CIC modules calculate coding information for the video at certain bit rates whereas the RE modules use this information to skip all encoding steps of a traditional encoder, except for the encoding of the residual. By reducing the amount of bits used to encode the residual, the RE modules can then provide bitstreams with personalized bit rates for several users at the same time. Each CIC module has approximately the same computational complexity as a traditional encoder, whereas an RE module has the approximate complexity of a decoder. The proposed architecture was evaluated for the high efficiency video coding standard, showing that the system achieves its goal of drastically reducing the computational complexity of low-delay live-streaming with many participants and suggesting that using less than six CIC modules results in the best tradeoff between compression efficiency and computational complexity.
Autors: Johan De Praeter;Glenn Van Wallendael;Jürgen Slowack;Peter Lambert;
Appeared in: IEEE Transactions on Multimedia
Publication date: Oct 2017, volume: 19, issue:10, pages: 2252 - 2266
Publisher: IEEE
 
» Video Object Discovery and Co-Segmentation with Extremely Weak Supervision
Abstract:
We present a spatio-temporal energy minimization formulation for simultaneous video object discovery and co-segmentation across multiple videos containing irrelevant frames. Our approach overcomes a limitation that most existing video co-segmentation methods possess, i.e., they perform poorly when dealing with practical videos in which the target objects are not present in many frames. Our formulation incorporates a spatio-temporal auto-context model, which is combined with appearance modeling for superpixel labeling. The superpixel-level labels are propagated to the frame level through a multiple instance boosting algorithm with spatial reasoning, based on which frames containing the target object are identified. Our method only needs to be bootstrapped with the frame-level labels for a few video frames (e.g., usually 1 to 3) to indicate if they contain the target objects or not. Extensive experiments on four datasets validate the efficacy of our proposed method: 1) object segmentation from a single video on the SegTrack dataset, 2) object co-segmentation from multiple videos on a video co-segmentation dataset, and 3) joint object discovery and co-segmentation from multiple videos containing irrelevant frames on the MOViCS dataset and XJTU-Stevens, a new dataset that we introduce in this paper. The proposed method compares favorably with the state-of-the-art in all of these experiments.
Autors: Le Wang;Gang Hua;Rahul Sukthankar;Jianru Xue;Zhenxing Niu;Nanning Zheng;
Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence
Publication date: Oct 2017, volume: 39, issue:10, pages: 2074 - 2088
Publisher: IEEE
 
» Video On-Demand Service via Wireless Broadcasting
Abstract:
Video on-demand (VoD) service is very popular over the mobile Internet. With the demand and quality of video contents become increasingly high, the capacity demand on mobile networks is explosively increasing. In order to sustainably accommodate the future traffic growth, operators such as Verizon start to offload video traffic with broadcasting. However, how to improve VoD users' quality of experience (QoE) under wireless broadcasting is still an open issue, where the major challenge is the time-varying wireless channel capacity. In this paper, we design a wireless VoD scheme with a periodic broadcasting approach. The basic idea is to fragment a video into segments, which are then delivered over different broadcasting channels periodically. We integrate network coding into our scheme so that packet redundancy can counteract the wireless unreliability. Moreover, we reveal the fundamental limits our proposed scheme can achieve in terms of two key QoE metrics: access delay and probability of continuous playout. We then show the intrinsic connections between the two QoE metrics and the choice of design parameters. The tradeoff between QoE improvement and bandwidth overhead is also presented. We implement the scheme in a testbed and demonstrate comprehensive experiment results.
Autors: Xiaohua Tian;Chang Zhao;Hui Liu;Jun Xu;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: Oct 2017, volume: 16, issue:10, pages: 2970 - 2982
Publisher: IEEE
 
» Video2vec Embeddings Recognize Events When Examples Are Scarce
Abstract:
This paper aims for event recognition when video examples are scarce or even completely absent. The key in such a challenging setting is a semantic video representation. Rather than building the representation from individual attribute detectors and their annotations, we propose to learn the entire representation from freely available web videos and their descriptions using an embedding between video features and term vectors. In our proposed embedding, which we call Video2vec, the correlations between the words are utilized to learn a more effective representation by optimizing a joint objective balancing descriptiveness and predictability. We show how learning the Video2vec embedding using a multimodal predictability loss, including appearance, motion and audio features, results in a better predictable representation. We also propose an event specific variant of Video2vec to learn a more accurate representation for the words, which are indicative of the event, by introducing a term sensitive descriptiveness loss. Our experiments on three challenging collections of web videos from the NIST TRECVID Multimedia Event Detection and Columbia Consumer Videos datasets demonstrate: i) the advantages of Video2vec over representations using attributes or alternative embeddings, ii) the benefit of fusing video modalities by an embedding over common strategies, iii) the complementarity of term sensitive descriptiveness and multimodal predictability for event recognition. By its ability to improve predictability of present day audiovisual video features, while at the same time maximizing their semantic descriptiveness, Video2vec leads to state-of-the-art accuracy for both fewand zero-example recognition of events in video.
Autors: Amirhossein Habibian;Thomas Mensink;Cees G. M. Snoek;
Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence
Publication date: Oct 2017, volume: 39, issue:10, pages: 2089 - 2103
Publisher: IEEE
 
» Virtual Carrier-Assisted DD-MB-OFDM Schemes for UDWDM Metro-Access Networks With Improved Tolerance to Four-Wave Mixing
Abstract:
Virtual carrier (VC)-assisted multiband orthogonal frequency division multiplexing (MB-OFDM) schemes with improved tolerance to the four-wave mixing (FWM) effect in direct-direction ultradense wavelength division multiplexing metro-access networks are proposed and discussed. The best scheme is identified from a set of alternative schemes chosen with potential to increase the tolerance to the FWM effect in VC-assisted MB-OFDM systems. A data rate per band and per user of the metro-access network of 10 and 25 Gb/s is considered for band spacings of 3.125 and 6.25 GHz, respectively. With the proposed MB-OFDM schemes, increase of the maximum acceptable power launched into the fiber can be achieved. This increase translates into a similar power budget (PB) improvement. With band spacings of 3.125 GHz, a PB improvement of 3 dB is achieved, which enables to double the number of users served by the metro-access network or to extend the reach of the optical distribution network (ODN) by about 12 km. For a 6.25-GHz band spacing, a PB improvement exceeding 4 dB is achieved, enabling to double the number of users and simultaneously extend the ODN coverage by about 5 km.
Autors: Pedro E. D. Cruz;Tiago M. F. Alves;Adolfo V. T. Cartaxo;
Appeared in: Journal of Lightwave Technology
Publication date: Oct 2017, volume: 35, issue:20, pages: 4468 - 4478
Publisher: IEEE
 
» Virtual Voltage Source Control for 2 × 27 MVA Machine Test Bench
Abstract:
In this paper, a special control solution called virtual voltage source (VVS) is developed for no-load tests of induction machines. This concept is applied to a 2 × 27 MVA high-power machine test bench where the test bench is requested to precisely characterize, e.g., 3 MW machines at no-load currents. The developed VVS thoroughly solves the stability issue of induction machines at low-speed ranges. A set of optimizations is presented here that systematically improves the voltage precision of the test bench. Experimental results prove that the proposed concept achieves 0.08–0.12% voltage unbalance, less than 3% current unbalance, with less than 0.3% harmonic-voltage-factor, and verified by more than 100 induction machines.
Autors: Jie Shen;Jingkui Shi;Bo Qu;Hongwu She;Jun Zhu;Yulong Li;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Oct 2017, volume: 53, issue:5, pages: 4579 - 4589
Publisher: IEEE
 
» Visibility-Aware Optimal Contagion of Malware Epidemics
Abstract:
Recent innovations in the design of computer viruses have led to new trade-offs for the attacker. Multiple variants of a malware may spread at different rates and have different levels of visibility to the network. In this work we examine the optimal strategies for the attacker so as to trade off the extent of spread of the malware against the need for stealth. We show that in the mean-field deterministic regime, this spread-stealth trade-off is optimized by computationally simple single-threshold policies. Specifically, we show that only one variant of the malware is spread by the attacker at each time, as there exists a time up to which the attacker prioritizes maximizing the spread of the malware, and after which she prioritizes stealth.
Autors: Soheil Eshghi;Saswati Sarkar;Santosh S. Venkatesh;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Oct 2017, volume: 62, issue:10, pages: 5205 - 5212
Publisher: IEEE
 
» Vision-Based Surgical Field Defogging
Abstract:
Fogged surgical field visualization that is a common and potentially harmful problem can lead to inappropriate device use and incorrectly targeted tissue and increase surgical risks in endoscopic surgery. This paper aims to remove fog or smoke on endoscopic video sequences to augment and maintain a direct and clear visualization of the operating field. A new visibility-driven fusion defogging framework is proposed for surgical endoscopic video processing. This framework first recovers the visibility and enhances the contrast of hazy images. To address the color infidelity problem introduced by the visibility recovery, the luminances of the recovered and enhanced images are fused in the gradient domain, and the fused luminance is reconstructed by solving the Poisson equation in the frequency domain. The proposed method is evaluated on clinical videos that were collected from prostate cancer surgery. The experimental results demonstrate that the proposed framework defogs endoscopic images more robustly than currently available methods. Additionally, our method also provides an effective way to improve the visual quality of medical or high-dynamic range images.
Autors: Xiongbiao Luo;A. Jonathan McLeod;Stephen E. Pautler;Christopher M. Schlachta;Terry M. Peters;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Oct 2017, volume: 36, issue:10, pages: 2021 - 2030
Publisher: IEEE
 
» Visual-INS Using a Human Operator and Converted Measurements
Abstract:
A method for intermittently aiding an inertial navigation system (INS) is explored in which a ground feature of unknown position is optically tracked over a short measurement epoch—one then refers to Visual-INS. In contrast to current machine vision-based research trends, a human operator is entrusted with visually tracking the ground feature. Converted measurements of the feature position are generated from successive bearing measurements, and the estimated aircraft position. A linear regression algorithm is then applied to the converted measurements providing an estimate of the INS horizontal velocity components’ errors and also accelerometer biases. At the completion of the measurement epoch, the INS is corrected by subtracting out the estimated velocity errors and using the estimated accelerometer biases. Aiding the INS in this manner provides a significant improvement in the accuracy of the INS-provided aircraft navigation state estimates when compared to those of a free/unaided INS. Applications for this autonomous navigation method include navigation in global positioning system denied environments and/or when the use of RF transmitting navigation aids is undesirable.
Autors: Meir Pachter;Turner J. Montgomery;
Appeared in: IEEE Transactions on Aerospace and Electronic Systems
Publication date: Oct 2017, volume: 53, issue:5, pages: 2359 - 2371
Publisher: IEEE
 
» VLSI Implementation of Deep Neural Network Using Integral Stochastic Computing
Abstract:
The hardware implementation of deep neural networks (DNNs) has recently received tremendous attention: many applications in fact require high-speed operations that suit a hardware implementation. However, numerous elements and complex interconnections are usually required, leading to a large area occupation and copious power consumption. Stochastic computing (SC) has shown promising results for low-power area-efficient hardware implementations, even though existing stochastic algorithms require long streams that cause long latencies. In this paper, we propose an integer form of stochastic computation and introduce some elementary circuits. We then propose an efficient implementation of a DNN based on integral SC. The proposed architecture has been implemented on a Virtex7 field-programmable gate array, resulting in 45% and 62% average reductions in area and latency compared with the best reported architecture in the literature. We also synthesize the circuits in a 65-nm CMOS technology, and we show that the proposed integral stochastic architecture results in up to 21% reduction in energy consumption compared with the binary radix implementation at the same misclassification rate. Due to fault-tolerant nature of stochastic architectures, we also consider a quasi-synchronous implementation that yields 33% reduction in energy consumption with respect to the binary radix implementation without any compromise on performance.
Autors: Arash Ardakani;François Leduc-Primeau;Naoya Onizawa;Takahiro Hanyu;Warren J. Gross;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Oct 2017, volume: 25, issue:10, pages: 2688 - 2699
Publisher: IEEE
 
» Voltage Suppression in Wire-Bond-Based Multichip Phase-Leg SiC MOSFET Module Using Adjacent Decoupling Concept
Abstract:
The silicon carbide (SiC) metal-oxide-semiconductor field-effect transistor (MOSFET) has a more serious voltage overshoot than the silicon insulated gate bipolar transistor (IGBT) due to the fundamental differences of the devices' parasitic parameters. In this paper, a novel low-inductance packaging structure for a wire-bond-based multichip phase-leg SiC MOSFET module to suppress the voltage overshoot is proposed. This packaging structure is based on the adjacent decoupling concept achieved by several decoupling capacitors to reduce the size of the commutation loop. The improvement in the packaging parasitics has been verified through an Ansys Q3D extractor. Furthermore, the influence of adjacent decoupling capacitors is analyzed in detail by frequency-domain analysis and verified with LTspice simulation analysis. Thereafter, the selection and thermal reliability of adjacent decoupling capacitors are expounded. The experimental results demonstrate the effectiveness and superiority of the proposed packaging structure.
Autors: Yu Ren;Xu Yang;Fan Zhang;Laili Wang;Kangping Wang;Wenjie Chen;Xiangjun Zeng;Yunqing Pei;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Oct 2017, volume: 64, issue:10, pages: 8235 - 8246
Publisher: IEEE
 
» Wafer Level Integration of 3-D Heat Sinks in Power ICs
Abstract:
In this paper, an innovative process flow developed to improve the thermal resistance of power ICs was presented. In this field, one of the major device failure mechanisms is related to the high temperatures reached during the working cycles due to the extremely critical electrical current densities. Therefore, heat transfer and dissipation are crucial aspects that need continuous improvements. Usual approaches to face this issue deal with package heat sinks design, solder selection, and wafer thinning. In this paper, a novel technological approach was settled, in which heat sinks microstructures were successfully integrated at wafer level stage on standard p-i-n diodes. To this aim, the bulk Si on the backside was partially replaced with Cu, a material characterized by a higher thermal conductivity material. Moreover, the well microstructures filled by Cu provide the advantage of wafer self-support, without requiring dedicated and more expensive thinning and handling technologies. An extensive characterization of the final devices was also carried out to evaluate the process and the thermal and electrical improvements. Finally, a failure analysis on selected devices was performed to identify any critical issue with the standard packaging process.
Autors: Isabella Para;S. L. Marasso;D. Perrone;M. G. Gentile;C. Sanfilippo;Giovanni Richieri;Luigi Merlin;D. Pugliese;M. Cocuzza;S. Ferrero;L. Scaltrito;C. F. Pirri;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Oct 2017, volume: 64, issue:10, pages: 4226 - 4232
Publisher: IEEE
 
» Wafer-Level Integration of an Advanced Logic-Memory System Through the Second-Generation CoWoS Technology
Abstract:
State-of-the-art silicon interposer technology of chip-on-wafer-on-substrate (CoWoS) containing the second-generation high bandwidth memory (HBM) has been applied for the first time in fabricating high-performance wafer-level system-in-package. An ultralarge Si interposer up to 1200mm2 made by a two-mask stitching process is used to form the basis of the second-generation CoWoS (CoWoS-2) to accommodate chips of logic and memory and achieve the highest possible performance. Yield challenges associated with the high warpage of such a large heterogeneous system are resolved to achieve high package yield. Compared to alternative interposer integration approaches such as chip-on-substrate, CoWoS offers more competitive design rule which results in better power consumption, transmission loss, and eye diagram. CoWoS-2 has positioned itself as a flexible 3-D IC platform for logic-memory heterogeneous integration between logic system-on-chip and HBM for various high-performance computing applications.
Autors: S. Y. Hou;W. Chris Chen;Clark Hu;Christine Chiu;K. C. Ting;T. S. Lin;W. H. Wei;W. C. Chiou;Vic J. C. Lin;Victor C. Y. Chang;C. T. Wang;C. H. Wu;Douglas Yu;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Oct 2017, volume: 64, issue:10, pages: 4071 - 4077
Publisher: IEEE
 
» Wall street occupies the blockchain - Financial firms plan to move trillions in assets to blockchains in 2018
Abstract:
WHEN BLOCKCHAINS first appeared nearly a decade ago as the technical backbone of Bitcoin, the world's leading cryptocurrency, they seemed to offer the masses a way to cut out the financial middleman. But now the big banks and other industry players are finding ways to spin the new tool to their advantage. Their blockchains share a vision that is precisely the opposite of the one laid out in the Bitcoin white paper, published under the pseudonym Satoshi Nakamoto in 2009. Like Nakamoto himself (or herself), you can own bitcoins without even stating your real name; nobody is in charge; and anybody can check the history of any given transaction. The financial industry's blockchains, however, are closed or, in their jargon, permissioned; to join one you must reveal your identity to a system administrator, who must then approve you.
Autors: Amy Nordrum;
Appeared in: IEEE Spectrum
Publication date: Oct 2017, volume: 54, issue:10, pages: 40 - 45
Publisher: IEEE
 
» Water Cold Plates Cooling in a Permanent Magnet Synchronous Motor
Abstract:
This paper presents a new water cooling system applied in a permanent magnet synchronous motor. This system is inspired by a widely used concept in electronics cooling. It consists of implementing some cold plates in the magnetic core. A lot of experimental tests have been carried out to evaluate the thermal performance of this cooling process and to estimate the influent parameters, such as ambient environment, flow rate, pressure stack, and distance between cold plates. Numerical approach based on computational fluid dynamics and finite elements method has been carried out to study the flow structure and the temperature distribution. Regarding the numerical results compared to the experimental results, it is noticed how much the flow structure has a significant influence on the overall thermal performance of this cooling design.
Autors: Aurélie Fasquelle;Daniel Laloy;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Oct 2017, volume: 53, issue:5, pages: 4406 - 4413
Publisher: IEEE
 
» Wavelet-Based Optical Flow Estimation of Instant Surface Currents From Shore-Based and UAV Videos
Abstract:
Instant fields of surface current are retrieved from shore-based and unmanned aerial vehicle videos by an optical flow (OF) method named “Typhoon.” This computer vision algorithm estimates dense 2-D 2-component velocity fields from the observable motion of foam patterns in the surf zone. Despite challenging image data resolution and quality, comparison of OF surface current estimates with measurements by an acoustic Doppler velocimeter reveals its ability to capture both wave-to-wave fluctuations and low-frequency variations. The method is also successfully applied to the monitoring of a “flash rip” event. This paper shows clearly the high potential of this method in the nearshore, where the rapid development of webcams and drones offers a large number of applications for swimming and surfing safety, engineering and naval security, and research purpose, by providing quantitative information.
Autors: Pierre Dérian;Rafael Almar;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Oct 2017, volume: 55, issue:10, pages: 5790 - 5797
Publisher: IEEE
 
» Wearable Biometric Performance Measurement System for Combat Sports
Abstract:
This paper presents the design of a wearable system for measurements of athlete’s performance in combat sports. The system provides objective measurements of athletes’ shots, posture, and movements, and of the effectiveness of their training. The proposed instrumentation is useful to overcome the limits of traditional training methods, which are characterized by a subjective evaluation of the training effectiveness by a coach. The measuring system consists of a distributed network of three battery-powered wireless-sensing node types, worn by the athletes, and one master node, which is in charge of signal acquisition and processing tasks. The master node elaborates training statistics and visualizes them, either in real time during a combat session, or off-line for posttraining analysis. The wearable measuring system has been tested through real combat training sessions of athletes with different weights, ages, and experiences, both male and female. Different from the state-of-art athletes’ biometric measurement machines, which are cumbersome and expensive, the proposed system is designed to ensure a low-cost and wearable implementation and to give easy-to-understand feedbacks during training, particularly to nonprofessional athletes.
Autors: Sergio Saponara;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Oct 2017, volume: 66, issue:10, pages: 2545 - 2555
Publisher: IEEE
 
» Wearable Microsystem for Minimally Invasive, Pseudo-Continuous Blood Glucose Monitoring: The e-Mosquito
Abstract:
This paper presents a wearable microsystem for minimally invasive, autonomous, and pseudo-continuous blood glucose monitoring, addressing a growing demand for replacing tedious fingerpricking tests for diabetic patients. Unlike prevalent solutions which estimate blood glucose levels from interstitial fluids or tears, our design extracts a whole blood sample from a small lanced skin wound using a novel shape memory alloy (SMA)-based microactuator and directly measures the blood glucose level from the sample. In vitro characterization determined that the SMA microactuator produced penetration force of 225 gf, penetration depth of 3.55 mm, and consumed approximately 5.56 mW·h for triggering. The microactuation mechanism was also evaluated by extracting blood samples from the wrist of four human volunteers. A total of 19 out of 23 actuations successfully reached capillary vessels below the wrists producing blood droplets on the surface of the skin. The integrated potentiostat-based glucose sensing circuit of our e-Mosquito device also showed a good linear correlation (R2 = 0.9733) with measurements using standard blood glucose monitoring technology. These proof-of-concept studies demonstrate the feasibility of the e-Mosquito microsystem for autonomous intermittent blood glucose monitoring.
Autors: Gang Wang;Michael D. Poscente;Simon S. Park;Christopher N. Andrews;Orly Yadid-Pecht;Martin P. Mintchev;
Appeared in: IEEE Transactions on Biomedical Circuits and Systems
Publication date: Oct 2017, volume: 11, issue:5, pages: 979 - 987
Publisher: IEEE
 
» Wearable tech for halloween - The gemma MO's embedded python lets you change your code on the fly [Resources_Tools]
Abstract:
Halloween is approaching, and with it a global parade of costumes. So I thought this would be the perfect time to try out a new wearable microcontroller from Adafruit Industries: the Gemma M0. Adafruit has been putting out wearable microcontrollers for several years. These differ from conventional controllers, such as the Arduino Uno, in that the wearables are typically more compact and use pads with large through holes for input and output, instead of pins. These holes make it easy to sew boards to fabric or tie conductive thread to the pads. What makes the Gemma M0 particularly interesting is that it runs CircuitPython, Adafruit's modified version of the Python language designed for embedded devices. (At this point, I should note that Limor Fried, the founder of Adafruit, is a member of IEEE Spectrum's editorial advisory board, but she played no role in the origination of this article.)
Autors: Stephen Cass;
Appeared in: IEEE Spectrum
Publication date: Oct 2017, volume: 54, issue:10, pages: 15 - 16
Publisher: IEEE
 
» Wearable Vector Electrical Bioimpedance System to Assess Knee Joint Health
Abstract:
Objective: We designed and validated a portable electrical bioimpedance (EBI) system to quantify knee joint health. Methods: Five separate experiments were performed to demonstrate the: 1) ability of the EBI system to assess knee injury and recovery; 2) interday variability of knee EBI measurements; 3) sensitivity of the system to small changes in interstitial fluid volume; 4) reducing the error of EBI measurements using acceleration signals; and 5) use of the system with dry electrodes integrated to a wearable knee wrap. Results: 1) The absolute difference in resistance ( R) and reactance (X) from the left to the right knee was able to distinguish injured and healthy knees (< 0.05); the absolute difference in R decreased significantly (p < 0.05) in injured subjects following rehabilitation. 2) The average interday variability (standard deviation) of the absolute difference in knee R was 2.5 Ω and for X was 1.2 Ω. 3) Local heating/cooling resulted in a significant decrease/increase in knee R (< 0.01). 4) The proposed subject position detection algorithm achieved 97.4% leave-one subject out cross-validated accuracy and 98.2% precision in detecting when the subject is in the correct position to take measurements. 5) Linear regression between the knee R and X measured using the wet electrodes and the designed wearable knee wrap were highly correlated ( R2 = 0.8 and 0.9, respectively). Co- clusion: This study demonstrates the use of wearable EBI measurements in monitoring knee joint health. Significance: The proposed wearable system has the potential for assessing knee joint health outside the clinic/lab and help guide rehabilitation.
Autors: Sinan Hersek;Hakan Töreyin;Caitlin N. Teague;Mindy L. Millard-Stafford;Hyeon-Ki Jeong;Miheer M. Bavare;Paul Wolkoff;Michael N. Sawka;Omer T. Inan;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Oct 2017, volume: 64, issue:10, pages: 2353 - 2360
Publisher: IEEE
 
» Weight-Balanced Timed Event Graphs to Model Periodic Phenomena in Manufacturing Systems
Abstract:
Timed event graphs (TEGs) are suitable to model manufacturing systems in which synchronization and delay phenomena appear. Since 1980s, TEGs are studied as a class of linear discrete event systems in idempotent semirings such as the (min,+) algebra. In this paper, we consider the class of weighted TEGs (WTEGs) that corresponds to TEGs where the edges have integer weights. By introducing nonunitary weights, WTEGs widen the class of manufacturing systems that can be modeled, especially systems with batches and duplications. Moreover, a subclass of WTEGs called weight-balanced TEGs (WB-TEGs) can be studied with the algebraic tools that stem from the theory of (min,+) linear systems. In this paper, the focus lies on some modeling issues for manufacturing systems. Besides cutting and palletization operations, it is shown that WB-TEGs are also well adapted to describe periodic routing policies and, in a symmetrical way, how to merge flows similar to a multiplexer. In order to simplify the modeling step, a class of cycloweighted TEGs (CW-TEGs) is introduced. It is an extension of WTEGs where the weights of the edges can change according to a periodic sequence. Finally, we propose some elements of modeling that can be described by CW-TEGs or equivalently with an input–output transfer relation in an appropriate idempotent semiring of operators. Note to Practitioners— The (min,+) linear system theory used in this paper aims at obtaining linear models for a subclass of man-designed systems, such as automated manufacturing systems or traffic networks. This theory has many analogies with the conventional linear system theory (for continuous systems) and it provides the basis to develop a specific control theory for man-made systems. More precisely, the theory of (min,+) linear systems is well suited to systems where the prevailing phenomena are sync- ronizations, delays, duplications, and batches. These phenomena arise, for example, in operations such as assembly/matching, cutting/lot splitting, and palletization/lot making. Among the possible representations, we can describe these systems by transfer functions obtained by the combination of a finite number of basic operators. This is analogous to block diagram in the conventional system theory, i.e., a transfer function describes the complete input-output behavior of a system. In the context of manufacturing systems, a transfer function describes the way a system maps an input flow of materials (raw part inputs) into an output flow (finished parts), without the necessity of simulation tools to predict this. Moreover, the transfer function thus obtained can be used to compute controllers in order to regulate the internal flows of a system, for instance to decrease internal stocks. In the case of an automated system, the obtained controllers can be implemented on a programmable logic controller as supplementary code. This paper focuses on the use of these algebraic tools in the model process of manufacturing systems and, in particular, on their ability to describe splitting and merging flows of materials.
Autors: Bertrand Cottenceau;Laurent Hardouin;Johannes Trunk;
Appeared in: IEEE Transactions on Automation Science and Engineering
Publication date: Oct 2017, volume: 14, issue:4, pages: 1731 - 1742
Publisher: IEEE
 
» Weighted Joint Collaborative Representation Based On Median-Mean Line and Angular Separation
Abstract:
Representation-based classifiers such as nearest regularized subspace (NRS) have been recently developed for hyperspectral image classification. The joint collaborative representation (JCR) and the weighted JCR (WJCR) methods added spatial information to the pixel-wise NRS classifier. While JCR adopts the same weights for extraction of spatial features from the surrounding pixels, WJCR uses the similarity between the central pixel and its surroundings to assign different weights to neighbor pixels. Two improved versions of WJCR are introduced in this paper. The first method, WJCR based on median-mean line, is proposed to cope with the negative effect of outlying neighbors. The second method, WJCR based on angular separation (AS), uses the benefits of the AS measurement to decrease the contribution of redundant information due to the highly correlated neighbors. The experimental results on some real hyperspectral data sets show the good efficiency of the proposed methods compared to other state-of-the-art NRS-based classifiers.
Autors: Maryam Imani;Hassan Ghassemian;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Oct 2017, volume: 55, issue:10, pages: 5612 - 5624
Publisher: IEEE
 
» Wellness Representation of Users in Social Media: Towards Joint Modelling of Heterogeneity and Temporality
Abstract:
The increasing popularity of social media has encouraged health consumers to share, explore, and validate health and wellness information on social networks, which provide a rich repository of Patient Generated Wellness Data (PGWD). While data-driven healthcare has attracted a lot of attention from academia and industry for improving care delivery through personalized healthcare, limited research has been done on harvesting and utilizing PGWD available on social networks. Recently, representation learning has been widely used in many applications to learn low-dimensional embedding of users. However, existing approaches for representation learning are not directly applicable to PGWD due to its domain nature as characterized by longitudinality, incompleteness, and sparsity of observed data as well as heterogeneity of the patient population. To tackle these problems, we propose an approach which directly learns the embedding from longitudinal data of users, instead of vector-based representation. In particular, we simultaneously learn a low-dimensional latent space as well as the temporal evolution of users in the wellness space. The proposed method takes into account two types of wellness prior knowledge: (1) temporal progression of wellness attributes; and (2) heterogeneity of wellness attributes in the patient population. Our approach scales well to large datasets using parallel stochastic gradient descent. We conduct extensive experiments to evaluate our framework at tackling three major tasks in wellness domain: attribute prediction, success prediction, and community detection. Experimental results on two real-world datasets demonstrate the ability of our approach in learning effective user representations.
Autors: Mohammad Akbari;Xia Hu;Fei Wang;Tat-Seng Chua;
Appeared in: IEEE Transactions on Knowledge and Data Engineering
Publication date: Oct 2017, volume: 29, issue:10, pages: 2360 - 2373
Publisher: IEEE
 
» What a Blast!: A Massive MIMO Radar System for Monitoring the Surface in Steel Industry Blast Furnaces
Abstract:
The main goal of surfacegauging radar applications is to obtain a complete image of a surface area inside a closed and possibly tightly sealed container filled with materials having sufficient reflectivity for highfrequency electromagnetic waves. Radar systems are applicable where standard acoustical or optical measurement techniques are strongly impaired due to harsh environmental conditions-such as extreme dust, heat, occasional heavy humidity, and aggressive chemicals-that occur, for example, inside a fully operative blast furnace.
Autors: Dominik Zankl;Stefan Schuster;Reinhard Feger;Andreas Stelzer;
Appeared in: IEEE Microwave Magazine
Publication date: Oct 2017, volume: 18, issue:6, pages: 52 - 69
Publisher: IEEE
 
» White Light Scanning Interferometry Based on Generalized Cross-Correlation Time Delay Estimation
Abstract:
Based on generalized cross-correlation time delay estimation (GCTDE), a new white light scanning interferometry (WLSI) method is proposed, in which the profile information usually achieved with the zero optical path difference (ZOPD) position is replaced with the relative displacement of interference signal between different pixels. Because all spectral information of interference signal (envelope and phase) and filter is utilized, the proposed GCTDE-based WLSI method reveals the advantages of higher accuracy and better noise suppression capability. Especially, in the case where the shape of interference signal envelope is irregular, the proposed method can achieve profile measurement with high accuracy while the conventional ZOPD position locating method cannot work. Moreover, by introducing laser interferometry system to calibrate the vertical displacement of a piezoelectric ceramic transducer scanning system, the measuring accuracy of the proposed GCTDE-based WLSI is further improved. Both the simulation and the experimental results demonstrate the significant accuracy advantage of the proposed GCTDE-based WLSI.
Autors: Yunfei Zhou;Liyun Zhong;Hongzhi Cai;Jindong Tian;Dong Li;Xiaoxu Lu;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 11
Publisher: IEEE
 
» White-Chaos Radar With Enhanced Range Resolution and Anti-Jamming Capability
Abstract:
Laser chaos is promising for constructing high range-resolution and anti-jamming radars, whereas the range resolution and anti-jamming capability are unfortunately limited by laser relaxation oscillation and external-cavity resonance, respectively. Here, we theoretically propose using a broadband white chaos generated by optical heterodyne of two chaotic external-cavity semiconductor lasers as source signal to construct a radar system with enhanced range resolution and anti-jamming capability. The white chaos not only has a white-noise-like wide spectrum without relaxation oscillation, but also has no signature of external-cavity resonance. Benefitting from these merits, the proposed white-chaos radar shows a marvelous unambiguous detection performance with subcentimeter range resolution. Moreover, the elimination of external-cavity resonance enables the randomness improvement of source signal, and resultantly, the anti-jamming capability is enhanced as well.
Autors: Longsheng Wang;Yuanyuan Guo;Pu Li;Tong Zhao;Yuncai Wang;Anbang Wang;
Appeared in: IEEE Photonics Technology Letters
Publication date: Oct 2017, volume: 29, issue:20, pages: 1723 - 1726
Publisher: IEEE
 
» Wholesale Electricity Markets: An Industry Game Changer
Abstract:
Two things happened 20 years ago that changed the electricity industry forever: the introduction of wholesale competition and the rising use of the Internet. For the New England region of the United States, this combination has led to unprecedented growth, innovation, and even excitement about the next chapter of this once-monolithic industry. When you compare New England's electric power system in the 1990s with today's power grid, the contrast is striking. Virtually every aspect of the region's power grid has changed-from the retirement of older, less efficient generation types, to the introduction of new, highly efficient technologies, and even from how electricity is bought and sold to how we use it.
Autors: Ellen Foley;
Appeared in: IEEE Potentials
Publication date: Oct 2017, volume: 36, issue:5, pages: 17 - 21
Publisher: IEEE
 
» Wide Bandgap Devices and Power Conversion Systems—Part I
Abstract:
Autors: Óscar Lucía;Xu She;Alex Q. Huang;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Oct 2017, volume: 64, issue:10, pages: 8190 - 8192
Publisher: IEEE
 
» Wideband and High-Gain Millimeter-Wave Antenna Based on FSS Fabry–Perot Cavity
Abstract:
A novel wideband and high-gain millimeter-wave antenna is presented. The wide 3 dB gain bandwidth is achieved by using Fabry–Perot cavity (FPC) and printed ridge-gap waveguide technologies. The FPC is formed by placing a dual-layer partially reflective surface (PRS) above a slot antenna operating at 60 GHz and fed by a printed ridge-gap waveguide for surface-wave suppression. The PRS is based on a 2-D printed unit cell, the unit cell composed of two different frequency-selective surfaces (FSS) provides a positive phase gradient over the desired frequency range. The impedance bandwidth of the proposed antenna is 18.4%, from 55.4 to 66.6 GHz. Moreover, the 3 dB gain bandwidth is 12.5%, from 58.6 to 66.4 GHz. A maximum gain of 16.8 dB is achieved; this is about 12.2 dB over the gain of the slot antenna only. Consistent radiation patterns are achieved over the operating bandwidth. Experimental and numerical results are presented to justify the improved antenna performance. This communication, to the best of our knowledge, is the first one to utilize a dual-layer printed FSS-based superstrate at 60 GHz to enhance the radiation characteristics of a printed ridge-gap waveguide-fed slot antenna.
Autors: Hussein Attia;M. Lamine Abdelghani;Tayeb A. Denidni;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Oct 2017, volume: 65, issue:10, pages: 5589 - 5594
Publisher: IEEE
 
» Wideband Decoupling Techniques for Dual-Polarized Bi-Static Simultaneous Transmit and Receive Antenna Subsystem
Abstract:
A wideband, bistatic, and dual-polarized simultaneous transmit and receive antenna subsystem with isolation >60 dB over 6–19 GHz band is demonstrated. The proposed configuration employs two quad-ridge horns fed by a ridge waveguide ortho-mode transducer (OMT) as transmitting (TX) and receiving (RX) antennas. The OMT enables dual-polarized high-power operation for the TX antenna over the entire bandwidth. The TX/RX antennas are flush mounted in a flat ground plane and oriented in D-plane to achieve similar isolation for both polarizations. Different decoupling techniques for increasing isolation between TX/RX antennas are investigated. Specifically, a high capacitive reactance bed of nails is designed to suppress TM polarized surface waves on the metallic ground plane. Moreover, a wideband planar and low-profile high-impedance surface is developed and performance thereof is compared to that of the other considered surfaces. Effect of recessing the RX antenna in an absorber is also discussed. Computational and experimental studies are conducted to demonstrate and validate the performance of the proposed antenna subsystem. Good impedance match, excellent radiation characteristics, and high isolation are achieved.
Autors: Prathap Valale Prasannakumar;Mohamed A. Elmansouri;Dejan S. Filipovic;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Oct 2017, volume: 65, issue:10, pages: 4991 - 5001
Publisher: IEEE
 
» Wideband Dipole Array Loaded Substrate Integrated H-Plane Horn Antenna for Millimeter Waves
Abstract:
A novel dipole array loaded substrate integrated H-plane sectoral horn antenna with a simple three-layered geometry is proposed. The dipole array integrated into two extra dielectric strips is connected to the top and bottom edges of the horn aperture. Both the horn aperture and the dipole array are effectively radiated together. A wide impedance bandwidth of 44% for dB that can cover the entire Ka-band is verified by a fabricated prototype. Additionally, stable symmetrical radiation pattern with low cross polarizations, low backward radiation, and gain up to 12 dBi with a variation of 3 dB can also be obtained throughout the whole operating band. The proposed antenna provides a new mean to design wideband substrate integrated horns with excellent endfire radiation, which would be attractive for future wideband and multiband millimeter-wave wireless applications, including the fifth generation (5G) mobile communications and the WiGig system.
Autors: Jingxue Wang;Yujian Li;Lei Ge;Junhong Wang;Meie Chen;Zhan Zhang;Zheng Li;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Oct 2017, volume: 65, issue:10, pages: 5211 - 5219
Publisher: IEEE
 
» Wideband Divide-by-4 Injection-Locked Frequency Divider Using Harmonic Mixer
Abstract:
This letter presents a wide locking range divide-by-4 LC injection-locked frequency divider (ILFD) implemented in the TSMC 0.18- 1P6M CMOS process. The single-stage divide-by-4 ILFD uses harmonic mixer and overlapped locking ranges to emulate a wide locking range. At the drain–source bias of 0.8 V, the ILFD-core power consumption is 7.09 mW. At the incident power of 0 dBm, the maximum locking range of the divide-by-4 ILFD is 6 GHz (37.5%) from 13 to 19 GHz. The ILFD comprises a capacitive cross-coupled nMOS pair and two shunt fourth-order RLC resonators. The die area is mm.
Autors: Sheng-Lyang Jang;Shih-Jie Jian;Ching-Wen Hsue;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Oct 2017, volume: 27, issue:10, pages: 924 - 926
Publisher: IEEE
 
» Wideband Frequency-Domain and Space-Domain Pattern Reconfigurable Circular Antenna Array
Abstract:
This paper presents a wideband circular antenna array with a frequency-domain and space-domain reconfigurable radiation pattern. A wideband circular array antenna is designed with omnidirectional radiation pattern, in azimuth direction, throughout the whole frequency band. The antenna array consists of eight TEM horn antennas. The antenna array exhibits an omnidirectional azimuthal radiation pattern when all eight ports are excited with signals of the same magnitude and phase. The antenna array is fed through eight reconfigurable bandstop filters and a power splitter. This enables it to provide an omnidirectional azimuthal pattern along with a single directional pattern null in a given spatial direction and at a certain frequency. Both the spatial direction and the frequency can be altered. The antenna works from 0.8 to 3 GHz. The antenna array will be useful in combating interference in wideband communication systems. It will also be of value in surveillance military applications.
Autors: Zhengpeng Wang;Peter S. Hall;James R. Kelly;Peter Gardner;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Oct 2017, volume: 65, issue:10, pages: 5179 - 5189
Publisher: IEEE
 
» Wideband Matching of Full-Wavelength Dipole With Reflector for Base Station
Abstract:
This communication introduces a wideband hybrid feeding method for full-wavelength dipole antennas with a reflector. A full-wavelength dipole is designed to cover the band from 698 to 960 MHz for cellular base station applications. Its matching circuit consists of a triple-tuned circuit and a quasi-quarter-wavelength impedance transformer. The proposed matching circuit can provide balanced feeding as a balun and has a compact size. The working mechanism and a complete design scheme of the proposed matching circuit are elaborated. The matching circuit is designed and optimized using a circuit theory model and then physically realized using microstrip lines based on full-wave simulation. The measured reflection coefficient is lesser than −14 dB across the entire band from 698 to 960 MHz, exhibiting a bandwidth of 32%. This is the first time that a wideband center-fed full-wavelength dipole is proposed.
Autors: Can Ding;Bevan Jones;Y. Jay Guo;Pei-Yuan Qin;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Oct 2017, volume: 65, issue:10, pages: 5571 - 5576
Publisher: IEEE
 
» Wideband Microstrip Comb-Line Linear Array Antenna Using Stubbed-Element Technique for High Sidelobe Suppression
Abstract:
This paper presents a novel wideband microstrip comb-line linear array antenna using end feeding developed in the millimeter-wave. The proposed antenna is designed for 28 GHz and has 12 elements. The reflection-canceling slit structure technique is adopted to develop a broadside beam with low reflections at the input. The proposed array is designed using stub-studded radiating elements that create more resonances to broaden the impedance bandwidth. The structure is a novel comb-line linear array antenna with stub-studded radiating elements and was developed by applying stubs to eight of the radiating elements of the array to increase the input impedance bandwidth. This helps to attain a wideband linear array antenna on a single dielectric substrate, which conventionally has a narrow bandwidth. The input impedance bandwidth is from 23.5 to 33.11 GHz, which is equivalent to a bandwidth of 33.95%. The radiation pattern bandwidth is from 27.5 to 29.25 GHz for sidelobe levels of below −20 dB equivalent to a bandwidth of 6.167%. The proposed antenna array presents features such as a simple structure with low fabrication cost and an enhanced impedance bandwidth with high sidelobe suppression. The feasibility of the proposed antenna array was evaluated by simulation and measurement in the millimeter-wave band.
Autors: Samuel Afoakwa;Young-Bae Jung;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Oct 2017, volume: 65, issue:10, pages: 5190 - 5199
Publisher: IEEE
 
» Wideband Over-the-Air RF Self-Interference Cancellation by an EML-Based Optical System With Baseband Predistortion
Abstract:
In this paper, we propose and experimentally demonstrate an optical self-interference cancellation (OSIC) system with baseband predistortion for wideband over-the-air in-band full-duplex (IBFD) communication. The key factors of OSIC bandwidth limitation are analyzed, and the solution toward it is proposed for the first time. Experimental results show that, by traditional OSIC under over-the-air condition, only narrow even zero band is with enough cancellation depth to satisfy IBFD. But with our proposed baseband predistortion scheme, deep OSIC depth is achieved over the whole 1 GHz/5 GHz baseband within the total 7–25 GHz available band of horn antennas. The employment of baseband predistortion obviously broadens the cancellation bandwidth of an EML-based OSIC system. The largest OSIC bandwidth for over-the-air IBFD communication is demonstrated so far.
Autors: Yunhao Zhang;Longsheng Li;Shilin Xiao;Meihua Bi;Yinghong Yu;Weisheng Hu;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 9
Publisher: IEEE
 
» Wideband Quasi-Nondiffraction Beam With Accurately Controllable Propagating Angle and Depth-of-Field
Abstract:
A wideband phase shift surface (PSS) antenna is proposed in this paper, which launches quasi-nondiffraction beam with accurately controllable inclination angle and depth-of-field. First, a novel method to generate the off-axis quasi-nondiffraction beam in an arbitrary direction is proposed. It modifies and further combines the design methods of the off-axis focusing antenna and the zero-order Bessel beam antenna. This method is helpful to improve the design precision of the depth-of-field of the beam. Then, one kind of hexagonal patch is employed as the element of the PSS. Its phase shift compensation capability can increase the bandwidth and improve the stability of the performance of the antenna over a wideband from 27 to 31 GHz. The results of numerical simulation, full-wave simulation, and experiment show that the proposed antenna can effectively generate the expected beam.
Autors: Yi Chen Zhong;Yu Jian Cheng;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Oct 2017, volume: 65, issue:10, pages: 5035 - 5042
Publisher: IEEE
 
» Wideband Resistive Sensors for Double-Ridged Waveguides
Abstract:
Two types of resistive sensors with flat frequency response for WRD840 and WRD250 double-ridged waveguides were developed. The first type of sensors is optimized for microwave power measurements inside the waveguide. The second type of sensors is connected to the particular horn antenna and optimized for microwave pulse power density (or electric field strength) measurements in free space. The flat frequency response of the sensors was designed by changing the parameters of the sensing element. Proposed sensors can measure high-power microwave pulses covering frequency ranges 0.84–2.0 GHz and 2.6–7.8 GHz.
Autors: Paulius Ragulis;Rimantas Simniškis;Mindaugas Dagys;Žilvinas Kancleris;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Oct 2017, volume: 45, issue:10, pages: 2748 - 2754
Publisher: IEEE
 
» Wideband Synthetic Aperture Sonar Backprojection With Maximization of Wave Number Domain Support
Abstract:
Wideband and widebeam synthetic aperture sonar (SAS) can provide information on the frequency- and aspect-dependent scattering in a scene. We suggest an approach to predict the quality of the sensor data over the available frequencies and aspect angles. We relate the typical spatial domain quality metrics to their wave number domain (WD) counterpart, and use these to map the data quality in WD. Because SAS arrays often are undersampled along-track, we pay particular attention to data degradation from aliasing. We use the proposed approach to examine how three SAS image formation algorithms based on time domain backprojection (TDBP) access data of different quality from wideband SAS systems. We illustrate the results with predictions for a generic SAS design and demonstrate the findings on two experimental systems. We observe that the maximum support of high-quality data is achieved through BP onto a high-resolution grid followed by WD filtering.
Autors: Stig Asle Vaksvik Synnes;Alan Joseph Hunter;Roy Edgar Hansen;Torstein Olsmo Sæbø;Hayden John Callow;Robbert van Vossen;Andreas Austeng;
Appeared in: IEEE Journal of Oceanic Engineering
Publication date: Oct 2017, volume: 42, issue:4, pages: 880 - 891
Publisher: IEEE
 
» Wideband Tunable Cross Polarization Converter Based on a Graphene Metasurface With a Hollow-Carved “H” Array
Abstract:
This paper presents a wideband tunable cross-polarization converter based on a graphene metasurface with a hollow-carved “H” array in the mid-infrared regions. The converter consists of three layers: the upper layer of the insulation dielectric layer is a periodic regular hollow-carved “H” array, and the bottom layer is a metal ground plane. Simulation is carried out by applying the frequency domain solver of the CST Microwave Studio software. The numerical simulation results show that the polarization converter transforms linear light into its cross-polarization light. The polarization conversion ratio is over 90% at 2.53 THz within the range of 34.39 to 36.92 THz, whereas the FWHM bandwidth is 3.87 THz within the range of 33.8 to 37.67 THz, about 11% of the central frequency. Thus, the cross-polarization converter can be dynamically tuned over a wide frequency range by altering the Fermi-energy of graphene, without reoptimizing and refabricating nanostructures. The operating frequency band of the proposed structure can also be tuned by changing the size of or while keeping the polarization conversion ratios high. Moreover, strong robustness is observed under the oblique incidence. Specifically, the polarization conversion ratios can be maintained at over 90% at angles of incidence of up to . Therefore, the proposed device has potential development and application in the manipulation of light polarization in the mid-infrared regions.
Autors: Ming Chen;Linzi Chang;Xi Gao;Hui Chen;Chongyun Wang;Xiaofei Xiao;Deping Zhao;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 11
Publisher: IEEE
 
» Winding Function Approach for Winding Analysis
Abstract:
The winding factor is an operand in order to consider the effect of winding distribution and chording on the spatial distribution of the magnetic field in the air gap of synchronous and induction machines. The sinusoidal functions for winding factor calculation presented in literature are not defined and valid for every irregular winding, e.g., single-layer fractional-slot, combined star-delta, multilayer (greater than two), and asymmetrical windings. Although the summation of induced voltage phasors (star of slots) is the most accurate method, asymmetrical windings require to be decomposed in symmetrical components. In this paper, in addition to deriving the symmetrical components for asymmetrical multiphase windings, the analytical formulation is presented to relate the harmonic content of winding functions to winding factors. The harmonic leakage factor is accurately formulated from the winding function instead of the Görges diagram without the need for summing up an infinite number of normalized winding factors quadratically. Without restriction of the number of layers and the distribution of the winding, including full-pitch, chorded and fractional-slot symmetrical and asymmetrical windings, the suggested analysis method is validated with the star of slots and sinusoidal functions of distribution and pitch factors, where applicable.
Autors: Seyed Morteza Raziee;Onur Misir;Bernd Ponick;
Appeared in: IEEE Transactions on Magnetics
Publication date: Oct 2017, volume: 53, issue:10, pages: 1 - 9
Publisher: IEEE
 
» Wireless Power Transfer to Millimeter-Sized Nodes Using Airborne Ultrasound
Abstract:
We propose the use of airborne ultrasound for wireless power transfer to mm-sized nodes, with intended application in the next generation of the Internet of Things (IoT). We show through simulation that ultrasonic power transfer can deliver 50 to a mm-sized node 0.88 m away from a ~ 50-kHz, 25-cm2 transmitter array, with the peak pressure remaining below recommended limits in air, and with load power increasing with transmitter area. We report wireless power recovery measurements with a precharged capacitive micromachined ultrasonic transducer, demonstrating a load power of 5 at a simulated distance of 1.05 m. We present aperture efficiency, dynamic range, and bias-free operation as key metrics for the comparison of transducers meant for wireless power recovery. We also argue that long-range wireless charging at the watt level is extremely challenging with existing technology and regulations. Finally, we compare our acoustic powering system with cutting edge electromagnetically powered nodes and show that ultrasound has many advantages over RF as a vehicle for power delivery. Our work sets the foundation for further research into ultrasonic wireless power transfer for the IoT.
Autors: Angad S. Rekhi;Butrus T. Khuri-Yakub;Amin Arbabian;
Appeared in: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Publication date: Oct 2017, volume: 64, issue:10, pages: 1526 - 1541
Publisher: IEEE
 
» Wirelessly Powered Backscatter Communications: Waveform Design and SNR-Energy Tradeoff
Abstract:
This letter shows that wirelessly powered backscatter communications is subject to a fundamental tradeoff between the harvested energy at the tag and the reliability of the backscatter communication, measured in terms of SNR at the reader. Assuming the RF transmit signal is a multisine waveform adaptive to the channel state information, we derive a systematic approach to optimize the transmit waveform weights (amplitudes and phases) in order to enlarge as much as possible the SNR-energy region. Performance evaluations confirm the significant benefits of using multiple frequency components in the adaptive transmit multisine waveform to exploit the nonlinearity of the rectifier and a frequency diversity gain.
Autors: Bruno Clerckx;Zati Bayani Zawawi;Kaibin Huang;
Appeared in: IEEE Communications Letters
Publication date: Oct 2017, volume: 21, issue:10, pages: 2234 - 2237
Publisher: IEEE
 
» Words of Gratitude [President's Message]
Abstract:
Presents the President’s message for this issue of the publication.
Autors: Ahmed A. Kishk;
Appeared in: IEEE Antennas and Propagation Magazine
Publication date: Oct 2017, volume: 59, issue:5, pages: 6 - 8
Publisher: IEEE
 
» Wrin’Tac: Tactile Sensing System With Wrinkle's Morphological Change
Abstract:
This paper describes an active tactile sensing system that selects sensing modalities based on specific sensing tasks, by changing its morphology, called Wrin’Tac. This paper was inspired by the human finger wet-induced wrinkle, which is usually observed when one soaks in warm water for a period, and has been indicated as an efficient transformation for enhancement of gripping stability in a wet environment. We proposed a device which is an integration of actuation (pneumatic actuator) and sensing elements (strain gauges) inside a thin, multilayered substrate. Under pressurization, the morphology of the substrate surface (both geometrical and mechanical characteristics) change with appearance of wrinkles. Especially, by formation of wrinkles, this device can change its shape so that the posture of embedded sensing elements (strain gauges) can vary and generate different responses depending on external load conditions. As a result, this device can actively select its sensing functions depending on specific sensing tasks. First, we created a model to investigate the dynamic changes in a strain gauges’ mechanical response under formation of wrinkles. Then, a prototype of this sensing device and its fabrication process were proposed to accomplish sensing tasks under vertical indentation and horizontal sliding action on its surface by using one type of strain gauge. This paper is an example of soft morphological control in tactile sensing, and is expected to open a new avenue to development of tactile sensing systems.
Autors: Van Anh Ho;Hideyasu Yamashita;Zhongkui Wang;Shinichi Hirai;Koji Shibuya;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Oct 2017, volume: 13, issue:5, pages: 2496 - 2506
Publisher: IEEE
 
» Zero-Sum Password Cracking Game: A Large-Scale Empirical Study on the Crackability, Correlation, and Security of Passwords
Abstract:
In this paper, we conduct a large-scale study on the crackability, correlation, and security of 145 million real world passwords, which were leaked from several popular Internet services and applications. To the best of our knowledge, this is the largest empirical study that has been conducted. Specifically, we first evaluate the crackability of 145 million real world passwords against 6+ state-of-the-art password cracking algorithms in multiple scenarios. Second, we examine the effectiveness and soundness of popular commercial password strength meters (e.g., Google, QQ) and the security impacts of username/email leakage on passwords. Finally, we discuss the implications of our results, analysis, and findings, which are expected to help both password users and system administrators to gain a deeper understanding of the vulnerability of real passwords against state-of-the-art password cracking algorithms, as well as to shed light on future password security research topics.
Autors: Shouling Ji;Shukun Yang;Xin Hu;Weili Han;Zhigong Li;Raheem Beyah;
Appeared in: IEEE Transactions on Dependable and Secure Computing
Publication date: Oct 2017, volume: 14, issue:5, pages: 550 - 564
Publisher: IEEE
 
» Zeroth-Order Self-Oscillating Active Integrated Antenna Using Cross-Coupled Pair
Abstract:
By ingeniously integrating a pair of zeroth-order resonators (ZORs) with a cross-coupled pair, for the first time, a novel zeroth-order self-oscillating active integrated antenna (AIA) is developed. Unlike the conventional feedback oscillating AIA, the new configuration is realized by, respectively, inserting a ZOR into each of the feedback paths of the cross-coupled pair to satisfy the Barkhausen criterion, and hence stabilize the oscillation. A self-oscillating AIA operates at the UHF radio frequency identification (RFID) band was demonstrated as a proof of concept. Benefitting from the infinite-wavelength property, the embedded ZORs are electrically large and capable of providing efficient power radiation into space. The oscillation parameters, meanwhile, remain good, thanks to the inherent high-quality factor property of metamaterial resonators. Without relying on ground radiation, the new design achieves good radiation and oscillation performances at the same time, hence adding extra flexibility on shaping the radiation pattern. According to the experimental results, the developed AIA, oscillating at 0.92 GHz, features a high dc-to-RF conversion efficiency of 52%, a moderate effective isotropic power of 8.9 dBm, and a low phase noise of −124.7 dBc/Hz at a 1 MHz offset from the carrier frequency. The design principle and experimental demonstration are thoroughly discussed.
Autors: Yu-Wei Chang;Tzyh-Ghuang Ma;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Oct 2017, volume: 65, issue:10, pages: 5011 - 5018
Publisher: IEEE
 
» [Hidden Word]
Abstract:
Various puzzles, games, humorous definitions, or mathematical that should engage the interest of readers.
Autors: Fred E. Gardiol;
Appeared in: IEEE Antennas and Propagation Magazine
Publication date: Oct 2017, volume: 59, issue:5, pages: 172 - 172
Publisher: IEEE
 
» [Meetings and Symposia]
Abstract:
Presents APS society upcoming meetings and events.
Autors: Raymond P. Wasky;
Appeared in: IEEE Antennas and Propagation Magazine
Publication date: Oct 2017, volume: 59, issue:5, pages: 112 - 113
Publisher: IEEE
 
» [MTT-S Ombuds Officer]
Abstract:
Presents remarks from the MTTS Ombudsman.
Autors: Edward C. Niehenke;
Appeared in: IEEE Microwave Magazine
Publication date: Oct 2017, volume: 18, issue:6, pages: 140 - 141
Publisher: IEEE
 
» [New Products]
Abstract:
Presents new products and services that are of interest to microwave engineers.
Autors: Ken Mays;
Appeared in: IEEE Microwave Magazine
Publication date: Oct 2017, volume: 18, issue:6, pages: 142 - 146
Publisher: IEEE
 

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