#### Electrical and Electronics Engineering publications abstract of: 09-2017 sorted by title, page: 3

» Analytical Formulas for the Coverage of Tunable Matching Networks for Reconfigurable Applications
 Abstract:Tunable matching networks (MNs) are essential components for agile radio frequency systems. To optimally design such networks, the total area they cover on the Smith chart needs to be determined. In this paper, the coverage areas of typical MNs have been determined analytically for the first time. It has been found that the coverage area is encompassed by up to five arcs. Analytical expressions for the centers and radii for these arcs have been derived. The theoretical analysis is provided for four typical MNs and verified by circuit simulation and measured data. Moreover, a dynamically load-modulated power amplifier has been designed using the presented theoretical techniques, which demonstrates a measured improvement in the power added efficiency of up to 5% in the frequency range of (0.8–0.9) GHz. Autors: Eyad Arabi;Kevin A. Morris;Mark A. Beach; Appeared in: IEEE Transactions on Microwave Theory and Techniques Publication date: Sep 2017, volume: 65, issue:9, pages: 3211 - 3220 Publisher: IEEE
» Analytical Formulas for Underwater and Aerial Object Localization by Gravitational Field and Gravitational Gradient Tensor
 Abstract:Object localization techniques have significant applications in civil fields and safety problems. A novel analytical formula is developed for accurate underwater and aerial object real-time localization by combining gravitational field and horizontal gravitational gradient anomalies. The proposed method enhances the accuracy of object localization and its excess mass estimation; it also effectively avoids the possible numerical instability and the singularity in the previous works. Finally, a synthetic underwater object navigation model was adopted to verify its performance. The results show that our newly developed method is more practical than existing methods. Autors: Jingtian Tang;Shuanggui Hu;Zhengyong Ren;Chaojian Chen;Xiao Xiao;Cong Zhou; Appeared in: IEEE Geoscience and Remote Sensing Letters Publication date: Sep 2017, volume: 14, issue:9, pages: 1557 - 1560 Publisher: IEEE
» Analytical Model for 2DEG Density in Graded MgZnO/ZnO Heterostructures With Cap Layer
 Abstract:In this paper, we develop a generic analytical model for 2-D electron gas (2DEG) density ( and threshold voltage ( of a fully strained graded ZnO-based heterostructure with a cap layer. The model is based on the continuity of electric field at the interfaces of different layers, dominant piezoelectric and spontaneous polarization components in different layers, Mg composition, and layer thickness. The generic model can be reduced to a simplified bilayer structure for calculating and . Results show that the graded heterostructure can result in higher values of 2DEG density and (absolute values) compared to the bilayer structure. A careful optimization of the structure is required to achieve a trade-off between and . An analytical expression of polarization charge density at buffer–barrier interface to better fit the experimental data available in the literature is also proposed. The model will be suitable for the design optimization of 2DEG density and for ZnO-based heterostructures. Autors: Rohit Singh;Md Arif Khan;Shaibal Mukherjee;Abhinav Kranti; Appeared in: IEEE Transactions on Electron Devices Publication date: Sep 2017, volume: 64, issue:9, pages: 3661 - 3667 Publisher: IEEE
» Analytical Model for Combined Study of Magnet Demagnetization and Eccentricity Defects in Axial Flux Permanent Magnet Synchronous Machines
 Abstract:A time-harmonic analytical model is presented for a combined study of demagnetization and rotor eccentricity in single-stator double-rotor axial flux permanent magnet synchronous machines (AFPMSM). Demagnetization defects are modeled by scaling the magnetization “square wave” by magnetization factors for each individual magnet on both rotors. Static, dynamic, and mixed rotor eccentricities are modeled using a permeance function. The original contribution of the model is that asymmetrical defects in the two air gaps of the machine can be described with acceptable accuracy and limited additional calculation time. The model is validated with a finite element method and experiments in both healthy and defected operations. Because the model has a short computation time, it is useful for real-time condition monitoring of any AFPMSM with double air gap and either concentrated or distributed windings. Autors: Jan De Bisschop;Peter Sergeant;Ahmed Hemeida;Hendrik Vansompel;Luc Dupré; Appeared in: IEEE Transactions on Magnetics Publication date: Sep 2017, volume: 53, issue:9, pages: 1 - 12 Publisher: IEEE
» Analytical Model for SDN Signaling Traffic and Flow Table Occupancy and Its Application for Various Types of Traffic
 Abstract:Software defined networking (SDN) has emerged as a promising networking paradigm overcoming various drawbacks of current communication networks.The control and data plane of switching devices is decoupled and control functions are centralized at the network controller. In SDN, each new flow introduces additional signaling traffic between the switch and the controller. Based on this traffic, rules are created in the flow table of the switch, which specify the forwarding behavior. To avoid table overflows, unused entries are removed after a predefined time-out period. Given a specific traffic mix, the choice of this time-out period affects the tradeoff between signaling rate and table occupancy. As a result, network operators have to adjust this parameter to enable a smooth and efficient network operation. Due to the complexity of this problem caused by the various traffic flows in a network, a suitable abstraction is necessary in order to derive valid parameter values in time. The contribution of this paper is threefold. First, we formulate a simple analytical model that allows optimizing the network performance with respect to the table occupancy and the signaling rate. Second, we validate the model by means of simulation. Third, we illustrate the impact of the time-out period on the signaling traffic and the flow table occupancy for different data-plane traffic mixes and characteristics. This includes scenarios with single application instances, as well as multiple application instances of different application types in an SDN-enabled network. Autors: Christopher Metter;Michael Seufert;Florian Wamser;Thomas Zinner;Phuoc Tran-Gia; Appeared in: IEEE Transactions on Network and Service Management Publication date: Sep 2017, volume: 14, issue:3, pages: 603 - 615 Publisher: IEEE
» Analytical Unit Cell Assembly for Efficient Chip/Package Power Distribution Network Modeling
 Abstract:Equivalent-circuit models for efficiently simulating 2-D power distribution networks (PDNs) in packages and chips are usually based on a star-type network, where all the branch networks have one port at the star center. This letter presents a simple analytical method for constructing the start network without relying on circuit simulators. The method is based only on the admittance matrix manipulation of each branch network. The star network assembly method is general since it has no limitation on the number of star branches. The method is applied to a specific PDN example and it is validated by means of a commercial circuit simulator as well as full-wave and measured data. Autors: F. de Paulis;S. Piersanti;A. Orlandi; Appeared in: IEEE Microwave and Wireless Components Letters Publication date: Sep 2017, volume: 27, issue:9, pages: 815 - 817 Publisher: IEEE
» Analyzing and Enhancing Dynamic Threshold Policy of Data Center Switches
 Abstract:Today’s data center switches usually employ on-chip shared memory; buffer management policy in them is essential to ensure fair sharing of memory among all ports. Among various polices, Dynamic Threshold  (DT) policy is widely used by switch vendors. Meanwhile, in data centers, distributed applications such as MapReduce often introduce micro-burst traffic into network and the packet dropping caused by micro-burst usually leads to serious performance degradation. When micro-burst traffic arrives at switches, DT is unable to fully utilize the buffer to absorb it. Therefore, in this paper, we theoretically deduce the sufficient conditions for packet dropping caused by micro-burst traffic, and quantitatively estimate the free buffer size when packets are dropped. The results show that the free buffer size can be very large when the number of overloaded ports is small. What’s worse, to ensure fair sharing of memory among output ports, packets from micro-burst traffic may be dropped even when the traffic size is much smaller than the buffer size. In light of these results, we propose the Enhanced Dynamic Threshold (EDT) policy, which can alleviate packet dropping caused by micro-burst traffic through fully utilizing the switch buffer and temporarily relaxing the fairness constraint. The simulation results show that EDT can absorb more micro-burst traffic than DT. Autors: Danfeng Shan;Wanchun Jiang;Fengyuan Ren; Appeared in: IEEE Transactions on Parallel and Distributed Systems Publication date: Sep 2017, volume: 28, issue:9, pages: 2454 - 2470 Publisher: IEEE
» Analyzing the Performance of Spectrum Sensing in Cognitive Radio Systems With Dynamic PU Activity
 Abstract:In this letter, we study the performance of the energy detector for opportunistic spectrum access (OSA) by a secondary user (SU) in dynamic scenarios, where a primary user (PU) switches from active to inactive at random time instances. Specifically, we model the PU activity using a two-state Markov chain and derive analytical expressions for the probabilities of detection and false alarm that explicitly consider the changes in the PU signal that may occur during the sensing interval by the SU. The expressions obtained are corroborated with numerical results obtained from simulations. Autors: Sara MacDonald;Dimitrie C. Popescu;Otilia Popescu; Appeared in: IEEE Communications Letters Publication date: Sep 2017, volume: 21, issue:9, pages: 2037 - 2040 Publisher: IEEE
» Angle Domain Signal Processing-Aided Channel Estimation for Indoor 60-GHz TDD/FDD Massive MIMO Systems
 Abstract:This paper proposes a practical channel estimation for 60-GHz indoor systems with the massive uniform rectangular array at base station. Through antenna array theory, the parameters of each channel path can be decomposed into the angular information and the channel gain information. We first prove that the true direction of arrivals of each uplink path can be extracted via an efficient array signal processing method. Then, the channel gain information could be obtained linearly with small amount of training resources, which significantly reduces the training overhead and the feedback cost. More importantly, the proposed scheme unifies the uplink/downlink channel estimations for both the time duplex division and frequency duplex division systems, making itself particularly suitable for protocol design. Compared with the existing channel estimation algorithms, the newly proposed one does not require any knowledge of channel statistics and can be efficiently deployed by the 2-D fast Fourier transform. Meanwhile, the number of user terminals simultaneously served can be increased from a sophisticatedly designed angle division multiple access scheme. Simulation results are provided to corroborate the proposed studies. Autors: Dian Fan;Feifei Gao;Gongpu Wang;Zhangdui Zhong;Arumugam Nallanathan; Appeared in: IEEE Journal on Selected Areas in Communications Publication date: Sep 2017, volume: 35, issue:9, pages: 1948 - 1961 Publisher: IEEE
» Ankle Joint Intrinsic Dynamics is More Complex than a Mass-Spring-Damper Model
 Abstract:This paper describes a new small signal parametric model of ankle joint intrinsic mechanics in normal subjects. We found that intrinsic ankle mechanics is a third-order system and the second-order mass-spring-damper model, referred to as IBK, used by many researchers in the literature cannot adequately represent ankle dynamics at all frequencies in a number of important tasks. This was demonstrated using experimental data from five healthy subjects with no voluntary muscle contraction and at seven ankle positions covering the range of motion. We showed that the difference between the new third-order model and the conventional IBK model increased from dorsi to plantarflexed position. The new model was obtained using a multi-step identification procedure applied to experimental input/output data of the ankle joint. The procedure first identifies a non-parametric model of intrinsic joint stiffness where ankle position is the input and torque is the output. Then, in several steps, the model is converted into a continuous-time transfer function of ankle compliance, which is the inverse of stiffness. Finally, we showed that the third-order model is indeed structurally consistent with agonist–antagonist musculoskeletal structure of human ankle, which is not the case for the IBK model. Autors: Ehsan Sobhani Tehrani;Kian Jalaleddini;Robert E. Kearney; Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering Publication date: Sep 2017, volume: 25, issue:9, pages: 1568 - 1580 Publisher: IEEE
» Application of Dual-Polarimetry SAR Images in Multitemporal InSAR Processing
 Abstract:Multitemporal polarimetric synthetic aperture radar (SAR) data can be used to estimate the dominant scattering mechanism of targets in a stack of SAR data and to improve the performance of SAR interferometric methods for deformation studies. In this letter, we developed a polarimetric form of amplitude difference dispersion (ADD) criterion for time-series analysis of pixels in which interferometric noise shows negligible decorrelation in time and space in small baseline algorithm. The polarimetric form of ADD is then optimized in order to find the optimum scattering mechanism of the pixels, which in turn is used to produce new interferograms with better quality than single-pol SAR interferograms. The selected candidates are then combined with temporal coherency criterion for final phase stability analysis in full-resolution interferograms. Our experimental results derived from a data set of 17 dual polarizations X-band SAR images (HH/VV) acquired by TerraSAR-X shows that using optimum scattering mechanism in the small baseline method improves the number of pixel candidates for deformation analysis by about 2.5 times in comparison with the results obtained from single-channel SAR data. The number of final pixels increases by about 1.5 times in comparison with HH and VV in small baseline analysis. Comparison between persistent scatterer (PS) and small baseline methods shows that with regards to the number of pixels with optimum scattering mechanism, the small baseline algorithm detects 10% more pixels than PS in agricultural regions. In urban regions, however, the PS method identifies nearly 8% more coherent pixels than small baseline approach. Autors: Mostafa Esmaeili;Mahdi Motagh;Andy Hooper; Appeared in: IEEE Geoscience and Remote Sensing Letters Publication date: Sep 2017, volume: 14, issue:9, pages: 1489 - 1493 Publisher: IEEE
» Application of Microgrids in Supporting Distribution Grid Flexibility
 Abstract:Distributed renewable energy resources have attracted significant attention in recent years due to the falling cost of the renewable energy technology, extensive federal and state incentives, and the application in improving load-point reliability. This growing proliferation, however, is changing the traditional consumption load curves by adding considerable levels of variability and further challenging the electricity supply–demand balance. In this paper, the application of microgrids in effectively capturing the distribution network net load variability, caused primarily by the prosumers, is investigated. Microgrids provide a viable and localized solution to this challenge, while removing the need for costly investments by the electric utility on reinforcing the existing electricity infrastructure. A flexibility-oriented microgrid optimal scheduling model is proposed and developed to coordinate the microgrid net load with the aggregated consumers/prosumers net load in the distribution network with a focus on ramping issues. The proposed coordination is performed to capture both inter- and intra-hour net load variabilities. Numerical simulations on a test distribution feeder with one microgrid and several consumers and prosumers exhibit the effectiveness of the proposed model. Autors: Alireza Majzoobi;Amin Khodaei; Appeared in: IEEE Transactions on Power Systems Publication date: Sep 2017, volume: 32, issue:5, pages: 3660 - 3669 Publisher: IEEE
» Application of Shifted Frequency Internal Equivalence to Multifrequency Scattering Problems
 Abstract:In this paper, a simple solution is presented for multifrequency electromagnetic scattering from inhomogeneous bodies. Shifted frequency internal equivalence is used to replace the electromagnetic problem at operating frequency by equivalent volume and current sources at internal frequency , and hence repeated calculation of system matrix as in the solution of volume integral equation at multiple frequencies is avoided. The volume field equation and surface tangent field equations obtained from the internal and external problems, the substitutes of the original scattering problem internally and externally, are solved by method of moments with pulse function expansion and point matching. Numerical results demonstrate that the proposed method is accurate and efficient within a wideband, fractional bandwidth being typically 100%. Autors: Sevda Özdemir;Alper Ünal;Adnan Köksal; Appeared in: IEEE Transactions on Antennas and Propagation Publication date: Sep 2017, volume: 65, issue:9, pages: 4790 - 4796 Publisher: IEEE
» Application-Layer FEC Scheme Configuration Optimization via Hybrid Simulated Annealing
 Abstract:An optimization technique based on an adapted combination of simulated annealing (SA) and tabu search (TS) is presented. This method aims at finding near-optimal unequal error protection (UEP) application-layer FEC code configurations. This approach is intended to smartly protect audio and video transmission over IP networks when hard time restrictions apply. The considered code is a UEP version of the widely-used Pro-MPEG COP3 codes enabling the use of several matrices of dissimilar size and thus of unequal recovery capability. Finding the optimal configuration frequently requires the evaluation of a large solution space. So, to fulfill the imposed constraints, SA is adapted to the specifics of the scenario. In particular, the annealing schedule is conditioned by the real-time restrictions. Furthermore, solution neighborhood structures are determined by a proposed definition of distance between protection configurations, which, jointly with TS, conditions the selection of candidate solutions. Experimental results show a significantly improved performance of the optimization process, which invariably fulfills imposed timing constraints, at the expense of a very low distortion increase, when compared to using exhaustive search. These results allow the use of UEP Pro-MPEG COP3 codes for protecting video and audio transmission, which distinctly outperforms the standard code in a wide range of scenarios. Autors: César Díaz;Julián Cabrera;Fernando Jaureguizar;Narciso García; Appeared in: IEEE Transactions on Broadcasting Publication date: Sep 2017, volume: 63, issue:3, pages: 479 - 493 Publisher: IEEE
» Approaching Capacity at High Rates With Iterative Hard-Decision Decoding
 Abstract:A variety of low-density parity-check (LDPC) ensembles have now been observed to approach capacity with message-passing decoding. However, all of them use soft (i.e., non-binary) messages and a posteriori probability decoding of their component codes. In this paper, we show that one can approach capacity at high rates using iterative hard-decision decoding (HDD) of generalized product codes. Specifically, a class of spatially coupled generalized LDPC codes with Bose–Chaudhuri–Hocquengham component codes is considered, and it is observed that, in the high-rate regime, they can approach capacity under the proposed iterative HDD. These codes can be seen as generalized product codes and are closely related to braided block codes. An iterative HDD algorithm is proposed that enables one to analyze the performance of these codes via density evolution. Autors: Yung-Yih Jian;Henry D. Pfister;Krishna R. Narayanan; Appeared in: IEEE Transactions on Information Theory Publication date: Sep 2017, volume: 63, issue:9, pages: 5752 - 5773 Publisher: IEEE
» Architecture of an Ultrasound System for Continuous Real-Time High Frame Rate Imaging
 Abstract:High frame rate (HFR) imaging methods based on the transmission of defocused or plane waves rather than focused beams are increasingly popular. However, the production of HFR images poses severe requirements both in the transmission and the reception sections of ultrasound scanners. In particular, major technical difficulties arise if the images must be continuously produced in real-time, i.e., without any acquisition interruption nor loss of data. This paper presents the implementation of the real-time HFR-compounded imaging application in the ULA-OP 256 research platform. The beamformer sustains an average output sample rate of 470 MSPS. This allows continuously producing coherently compounded images, each of 64 lines by 1280 depths (here corresponding to 15.7 mm width and 45 mm depth, respectively), at frame rates up to 5.3 kHz. Imaging tests addressed to evaluate the achievable speed and quality performance were conducted on phantom. Results obtained by real-time compounding frames obtained with different numbers of steering angles between +7.5° and −7.5° are presented. Autors: Enrico Boni;Luca Bassi;Alessandro Dallai;Valentino Meacci;Alessandro Ramalli;Monica Scaringella;Francesco Guidi;Stefano Ricci;Piero Tortoli; Appeared in: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control Publication date: Sep 2017, volume: 64, issue:9, pages: 1276 - 1284 Publisher: IEEE
» ARCNET Never Received Enough Credit [History]
 Abstract:In the March 2017 issue of IEEE Industrial Electronics Magazine, the authors of "The Future of Industrial Communication" provided a comprehensive chart of industrial communication milestones ranging from the 1960s to the present [1]. But there was one glaring omission-the Attached Resource Computer Network (ARCNET). As a former chair of the ARCNET Trade Association (ATA), I feel obligated to defend ARCNET as the first local area network (LAN), which is still in use today [2]. It is a technology that impacted both the office and industrial automation industries. It is elegant, fast, robust-and it works! The technology was deemed by the press as "the Rodney Dangerfield of network computing," and its proponents were called fanatical [3]. Although ARCNET has failed to receive the recognition it deserves, it is a successful technology that has been used in applications never imagined by its creators. Autors: George Thomas; Appeared in: IEEE Industry Applications Magazine Publication date: Sep 2017, volume: 23, issue:5, pages: 7 - 13 Publisher: IEEE
» Area Determination of Diabetic Foot Ulcer Images Using a Cascaded Two-Stage SVM-Based Classification
 Abstract:The standard chronic wound assessment method based on visual examination is potentially inaccurate and also represents a significant clinical workload. Hence, computer-based systems providing quantitative wound assessment may be valuable for accurately monitoring wound healing status, with the wound area the best suited for automated analysis. Here, we present a novel approach, using support vector machines (SVM) to determine the wound boundaries on foot ulcer images captured with an image capture box, which provides controlled lighting and range. After superpixel segmentation, a cascaded two-stage classifier operates as follows: in the first stage, a set of k binary SVM classifiers are trained and applied to different subsets of the entire training images dataset, and incorrectly classified instances are collected. In the second stage, another binary SVM classifier is trained on the incorrectly classified set. We extracted various color and texture descriptors from superpixels that are used as input for each stage in the classifier training. Specifically, color and bag-of-word representations of local dense scale invariant feature transformation features are descriptors for ruling out irrelevant regions, and color and wavelet-based features are descriptors for distinguishing healthy tissue from wound regions. Finally, the detected wound boundary is refined by applying the conditional random field method. We have implemented the wound classification on a Nexus 5 smartphone platform, except for training which was done offline. Results are compared with other classifiers and show that our approach provides high global performance rates (average sensitivity = 73.3%, specificity = 94.6%) and is sufficiently efficient for a smartphone-based image analysis. Autors: Lei Wang;Peder C. Pedersen;Emmanuel Agu;Diane M. Strong;Bengisu Tulu; Appeared in: IEEE Transactions on Biomedical Engineering Publication date: Sep 2017, volume: 64, issue:9, pages: 2098 - 2109 Publisher: IEEE
» Areal Geometric Effects of a ZnO Charge-Trap Layer on Memory Transistor Operations for Embedded-Memory Circuit Applications
 Abstract:The areal geometric effects of a ZnO charge-trap layer (CTL) on the device characteristics of a charge-trap memory thin-film transistor were investigated for embedded-memory circuit applications. While the device with a larger overlapped region between the CTL and active channel exhibited a larger memory window and faster program speed, in order to guarantee long-term memory retention even under higher drain bias conditions, the CTL size should be minimized to reduce the overlapped area. The resulting device behavior is a compromise between the modulations of the number of trap sites within the ZnO CTL and the electric field concentration caused by the configuration of the edge area in the overlapped region. Autors: Da-Jeong Yun;Jun-Yong Bak;Chun-Won Byun;Sung-Min Yoon; Appeared in: IEEE Electron Device Letters Publication date: Sep 2017, volume: 38, issue:9, pages: 1263 - 1265 Publisher: IEEE
» Array Architectures for 3-D NAND Flash Memories
 Abstract:NAND Flash memories have changed and keep changing our lives. In the past two decades, NAND-based systems, in the form of Flash cards and USB keys, have replaced films and floppy disks. But disruption did not stop there. Today, NAND is really ubiquitous, as it plays the role of storage element inside smartphones and tablets; even further, it is now expanding its reach because solid-state drives (SSDs), i.e., drives built with several NAND devices, are replacing hard disk drives (HDDs) in more and more applications. To fuel this continuous evolution, NAND has to remain very aggressive in terms of cost per bit. When approaching 10-nm technologies, planar NAND is running out of steam: industry and academia have worked hard on finding a solution to this problem for more than a decade. Three-dimensional integration turned out to be the most promising alternative, and it is now eventually reaching the market. This paper is about 3-D NAND Flash memories and the related integration challenges. Charge trap and floating gate 3-D technologies will be discussed with the aid of several bird’s-eye views. Advanced layout techniques will thoroughly be analyzed. Finally, future scaling trends will be presented. Autors: Rino Micheloni;Seiichi Aritome;Luca Crippa; Appeared in: Proceedings of the IEEE Publication date: Sep 2017, volume: 105, issue:9, pages: 1634 - 1649 Publisher: IEEE
» Array Termination Impacts in Advanced SRAM
 Abstract:An essential goal of the static random access memory (SRAM) array termination design is to both terminate as well as maintain a homogeneous environment for the active edge cells in the array. Local layout effects (LLEs) in the array termination design can exert influence on the active array SRAM devices in close proximity to the termination region, which can lead to undesirable inhomogenuities in the array. The impact of LLEs, originating from the array termination design, on SRAM read performance and fail count, are examined using a 14-nm FinFET technology. Large-scale SRAM read performance statistics are analyzed to identify elevated read currents and low-voltage fail counts associated with the array termination. The root cause and modulating factors are explored, and potential solution paths are discussed. Autors: Randy W. Mann;Sandeep Puri;Sheng Xie;Daniel Marienfeld;Joseph Versaggi;Bianzhu Fu;Michael Gribelyuk;Ratheesh R. Thankalekshmi;Xiaoqiang Zhang;Hui Zang;Chad E. Weintraub; Appeared in: IEEE Transactions on Very Large Scale Integration Systems Publication date: Sep 2017, volume: 25, issue:9, pages: 2449 - 2457 Publisher: IEEE
» Arsenic Phosphorus Monolayer: A Promising Candidate for H2S Sensor and NO Degradation With High Sensitivity and Selectivity
 Abstract:The sensing behaviors of arsenic phosphorus (AsP) for nitric oxide (NO) and hydrogen sulfide (H2S) are investigated by means of the density functional theory and the nonequilibrium Green’s function method. The calculated adsorption energy and charge transfer of H2S molecule on silicon-doped AsP (Si-AsP) are 0.352 eV and 0.106 , respectively, indicating the presence of physisorption process. The H2S adsorption on aluminum-doped AsP is a chemisorption process with covalent bond formed. Furthermore, the calculated current–voltage (–) relation clearly shows that the substrate with and without H2S adsorption exhibits distinct responses. This property indicates that Si-AsP is expected to be the high-performance H2S sensor. The chemisorption is also observed in Si-/Al-doped AsP with NO molecule adsorption, suggesting the high potential in the application of NO degradation. Autors: Yingying Zhang;Chunjian Tan;Qun Yang;Huaiyu Ye;Xian-Ping Chen; Appeared in: IEEE Electron Device Letters Publication date: Sep 2017, volume: 38, issue:9, pages: 1321 - 1324 Publisher: IEEE
» Artefacts in Marine Digital Terrain Models: A Multiscale Analysis of Their Impact on the Derivation of Terrain Attributes
 Abstract:Data acquisition artefacts are commonly found in multibeam bathymetric data, but their effects on mapping methodologies using geographic information system techniques have not been widely explored. Artefacts have been extensively studied in terrestrial settings, but their study in a marine context has currently been limited to engineering and surveying technology development in order to reduce their amplitude during data collection and postprocessing. Knowledge on how they propagate to further analyses like environmental characterization or terrain analysis is scant. The goal of this paper is to describe the contribution of different types of artefacts to marine terrain attributes at multiple scales. Using multibeam bathymetric data from German Bank, off Nova Scotia (Canada), digital bathymetric models (DBMs) were computed at five different spatial resolutions. Ten different amplitudes of heave, pitch, roll, and time artefacts were artificially introduced to generate altered DBMs. Then, six terrain attributes were derived from each of the reference and altered DBMs. Relationships between the amplitude of artefacts and the statistical and spatial distributions of: 1) altered bathymetry and terrain attributes surfaces and 2) errors caused by the artefacts were modeled. Spatial similarity between altered and reference surfaces was also assessed. Results indicate that most artefacts impact spatial similarity and that pitch and roll significantly impact the statistical distribution of DBMs and terrain attributes while time and heave artefacts have a more subtle impact. Results also confirm the relationship between spatial data quality and spatial scale, as finer-scale data were impacted by artefacts to a greater degree than broader-scale data. Autors: Vincent Lecours;Rodolphe Devillers;Vanessa L. Lucieer;Craig J. Brown; Appeared in: IEEE Transactions on Geoscience and Remote Sensing Publication date: Sep 2017, volume: 55, issue:9, pages: 5391 - 5406 Publisher: IEEE
» Assessing the Benefits of Drug Delivery by Nanocarriers: A Partico/Pharmacokinetic Framework
 Abstract:Objective: An in vivo kinetic framework is introduced to analyze and predict the quantitative advantage of using nanocarriers to deliver drugs, especially anticancer agents, compared to administering the same drugs in their free form. Methods: This framework recognizes three levels of kinetics. First is the particokinetics associated with deposition of nanocarriers into tissues associated with drug effect and toxicity, their residence inside those tissues, and elimination of the nanocarriers from the body. Second is the release pattern in time of free drug from the nanocarriers. Third is the pharmacokinetics of free drug, as it relates to deposition and elimination processes in the target and toxicity associated tissues, and total body clearance. A figure of merit, the drug targeting index (DTI), is used to quantitate the benefit of nanocarrier-based drug delivery by considering the effects of preferential deposition of nanoparticles into target tissues and relative avoidance of tissues associated with drug toxicity, compared to drug that is administered in its free form. Results: General methods are derived for calculating DTI when appropriate particokinetic, pharmacokinetic, and drug release rate information is available, and it is shown that relatively simple algebraic forms result when some common assumptions are made. Conclusion: This approach may find use in developing and selecting nanocarrier formulations, either for populations or for individuals. Autors: Ronald A. Siegel;Ameya R. Kirtane;Jayanth Panyam; Appeared in: IEEE Transactions on Biomedical Engineering Publication date: Sep 2017, volume: 64, issue:9, pages: 2176 - 2185 Publisher: IEEE
» Assessing the Feasibility of the Use of Video Motion Magnification for Measuring Microdisplacements
 Abstract:There are different techniques for measuring microdisplacements. The purpose of this paper was to ascertain whether a method of video motion magnification (VMM) can be used for measuring such displacements. For this, standard video devices (a digital single-lens reflex camera and a webcam) were used to record subtle movements of an object, and the results of the VMM technique were contrasted with an air-coupled ultrasonic sensing method that could achieve submicrometer accuracy. The results of the VMM technique highly correlate with those achieved using the ultrasonic sensor, showing that the former can accurately measure displacements in the range from about 5 to 40 from a distance of about 1 m. The temporal characteristics of the moving object were well preserved. The VMM technique is an alternative to other modalities for measuring microdisplacements and has the advantage of being noncontact, long-range, and relatively low-cost. Autors: Mateusz P. Popek;Monika E. Danielewska;D. Robert Iskander; Appeared in: IEEE Transactions on Instrumentation and Measurement Publication date: Sep 2017, volume: 66, issue:9, pages: 2329 - 2336 Publisher: IEEE
» Assessment of Macro Fiber Composite Sensors for Measurement of Acoustic Partial Discharge Signals in Power Transformers
 Abstract:This paper presents a performance assessment of macro fiber composite (MFC) sensors for measuring acoustic emission (AE) signals from partial discharges (PD) in power transformers filled with mineral oil. MFC sensors are low-profile and flexible, allowing them to be attached to uneven surfaces, such as a transformer wall. Two types of MFC sensors were assessed: P1 (d33 effect) and P2 (d31 effect), which are optimized for different deformations in the structure, such as elongation and contraction, respectively. In addition, a conventional AE sensor, R15I-AST model from Physical Acoustics South America, was also used as a reference for comparative analysis. Four metrics were applied to the signals: root mean square, energy criterion, Akaike criterion, power spectral density, and correlation. The experimental results indicate a high similarity between the MFC sensors and the conventional AE sensor, which expands the research field in acoustic PD measurement in power transformers by using low-cost and flexible sensors. Autors: Bruno Albuquerque de Castro;Danilo de Melo Brunini;Fabricio Guimarães Baptista;André Luiz Andreoli;José Alfredo Covolan Ulson; Appeared in: IEEE Sensors Journal Publication date: Sep 2017, volume: 17, issue:18, pages: 6090 - 6099 Publisher: IEEE
» Assessment of the Effectiveness of Energy Storage Resources in the Frequency Regulation of a Single-Area Power System
 Abstract:An energy storage resource (ESR) has outstanding ramping capability, but its limited energy disables the provision of regulation service around the clock. As a comparison, a conventional generator (CG) is not restricted by the released energy, but the ramp rate is limited. In this paper, a method is proposed to evaluate the effectiveness of ESRs providing frequency regulation service in a single-area system. We measure the performance of frequency regulation by the standard deviation of system frequency excursions, and define the regulation requirement of an isolated power system as the minimum regulation capacity which satisfies the desired regulation performance. By analyzing the regulation requirements under different combinations of regulation resources, we can quantitatively compare the effectiveness of CGs and ESRs. Case studies show that ESRs can reduce regulation requirements, indicating that they are more effective than CGs in frequency regulation. However, they become less effective and even outperformed by CGs when they constitute a larger portion of the system regulation capacity. Autors: Fang Zhang;Zechun Hu;Xu Xie;Jing Zhang;Yonghua Song; Appeared in: IEEE Transactions on Power Systems Publication date: Sep 2017, volume: 32, issue:5, pages: 3373 - 3380 Publisher: IEEE
» Asymmetric Binary Coding for Image Search
 Abstract:Learning to hash has attracted broad research interests in recent computer vision and machine learning studies, due to its ability to accomplish efficient approximate nearest neighbor search. However, the closely related task, maximum inner product search (MIPS), has rarely been studied in this literature. To facilitate the MIPS study, in this paper, we introduce a general binary coding framework based on asymmetric hash functions, named asymmetric inner-product binary coding (AIBC). In particular, AIBC learns two different hash functions, which can reveal the inner products between original data vectors by the generated binary vectors. Although conceptually simple, the associated optimization is very challenging due to the highly nonsmooth nature of the objective that involves sign functions. We tackle the nonsmooth optimization in an alternating manner, by which each single coding function is optimized in an efficient discrete manner. We also simplify the objective by discarding the quadratic regularization term which significantly boosts the learning efficiency. Both problems are optimized in an effective discrete way without continuous relaxations, which produces high-quality hash codes. In addition, we extend the AIBC approach to the supervised hashing scenario, where the inner products of learned binary codes are forced to fit the supervised similarities. Extensive experiments on several benchmark image retrieval databases validate the superiority of the AIBC approaches over many recently proposed hashing algorithms. Autors: Fumin Shen;Yang Yang;Li Liu;Wei Liu;Dacheng Tao;Heng Tao Shen; Appeared in: IEEE Transactions on Multimedia Publication date: Sep 2017, volume: 19, issue:9, pages: 2022 - 2032 Publisher: IEEE
» Asymmetric Optical Bus Coupler for Interruption-Free Short-Range Connections on Board and Module Level
 Abstract:In this paper, we present a bidirectional interruption-free multimode waveguide coupler for optical bus systems on board and module level. The principle is based on directional core–core coupling and allows for adjustable coupling powers by tuning the overlap area. By adding a bending to one of the coupling partners, it is possible to obtain specific asymmetric coupling rates depending on the coupling direction (module to bus or vice versa). The proposed approach is extensively analyzed by optical simulation (beam propagation method) and measurements including experiments on the attenuation, the coupling rate, and the bit rate performance. Autors: Lukas Lorenz;Krzysztof Nieweglowski;Zaid Al-Husseini;Niels Neumann;Dirk Plettemeier;Klaus-Jürgen Wolter;Thomas Reitberger;Jörg Franke;Karlheinz Bock; Appeared in: Journal of Lightwave Technology Publication date: Sep 2017, volume: 35, issue:18, pages: 4033 - 4039 Publisher: IEEE
» Asymmetrically Clipped Absolute Value Optical OFDM for Intensity-Modulated Direct-Detection Systems
 Abstract:Orthogonal frequency division multiplexing (OFDM) is attracting increasing attention in optical communication systems, thanks to its inherent benefits such as high spectral efficiency and resistance to frequency-selective channels. In this paper, a novel energy and spectrally efficient scheme called asymmetrically clipped absolute value optical OFDM (AAO-OFDM) is proposed for intensity-modulated direct-detection systems. In AAO-OFDM, absolute value optical OFDM (AVO-OFDM) signals on the even subcarriers and asymmetrically clipped optical OFDM (ACO-OFDM) signals on the odd subcarriers are combined for simultaneous transmission, which employs all the subcarriers requiring no dc biases. For AVO-OFDM scheme, the frequency symbols are first modulated on the even subcarriers, which are then fed into an inverse fast Fourier transform block. Afterward, the absolute values of the bipolar time-domain signals are taken to guarantee non-negativity, while their signs are mapped to the complex-valued symbols and modulated on the odd subcarriers. Since there remain unused odd subcarriers, other useful symbols can be modulated on them, which leads to the conventional ACO-OFDM scheme. At the receiver, the ACO-OFDM symbols on the odd subcarriers are demodulated first, which are reconstructed and removed from the received signals. Afterward, the remaining signals are utilized to detect the AVO-OFDM symbols with the aid of the demodulated sign symbols on the odd subcarriers. Theoretical analysis and simulation results show that AAO-OFDM has lower peak-to-average power ratio than other optical OFDM schemes, which makes it less sensitive to the nonlinearity of the optical devices. Furthermore, it achieves better bit error rate performance compared to its counterparts for the same spectral efficiency. Autors: Ruowen Bai;Qi Wang;Zhaocheng Wang; Appeared in: Journal of Lightwave Technology Publication date: Sep 2017, volume: 35, issue:17, pages: 3680 - 3691 Publisher: IEEE
» Asymptotic Outage Analysis of HARQ-IR Over Time-Correlated Nakagami- $m$ Fading Channels
 Abstract:In this paper, outage performance of hybrid automatic repeat request with incremental redundancy (HARQ-IR) is analyzed. Unlike prior analyses, time-correlated Nakagami- fading channel is considered. The outage analysis thus involves the probability distribution analysis of a product of multiple correlated shifted Gamma random variables and is more challenging than prior analyses. Based on the findings of the conditional independence of the received signal-to-noise ratios, the outage probability is exactly derived by using conditional Mellin transform. Specifically, the outage probability of HARQ-IR under time-correlated Nakagami- fading channels can be written as a weighted sum of outage probabilities of HARQ-IR over independent Nakagami fading channels, where the weightings are determined by a negative multinomial distribution. This result enables not only an efficient truncation approximation of the outage probability with uniform convergence but also asymptotic outage analysis to further extract clear insights, which have never been discovered for HARQ-IR even under fast fading channels. The asymptotic outage probability is then derived in a simple form, which clearly quantifies the impacts of transmit powers, channel time correlation, and information transmission rate. It is proved that the asymptotic outage probability is an inverse power function of the product of transmission powers in all HARQ rounds, an increasing function of the channel time correlation coefficients, and a monotonically increasing and convex function of information transmission rate. The simple expression of the asymptotic result enables optimal power allocation and optimal rate selection of HARQ-IR with low complexity. Finally, numerical results are provided to verify our analytical results and justify the application of the asymptotic re- ult for optimal system design. Autors: Zheng Shi;Shaodan Ma;Guanghua Yang;Kam-Weng Tam;Minghua Xia; Appeared in: IEEE Transactions on Wireless Communications Publication date: Sep 2017, volume: 16, issue:9, pages: 6119 - 6134 Publisher: IEEE
» Asymptotically Equivalent Sequences of Matrices and Capacity of a Discrete-Time Gaussian MIMO Channel With Memory
 Abstract:Using some recent results on asymptotically equivalent sequences of matrices, we present in this paper, a new derivation of the capacity formula given by Brandenburg and Wyner for a discrete-time Gaussian multiple-input-multiple-output channel with memory. In this paper, we tackle not only the case considered by them, where the number of channel inputs and the number of channel outputs are the same, but also when both numbers are different. Autors: Jesús Gutiérrez-Gutiérrez;Pedro M. Crespo;Marta Zárraga-Rodríguez;Bjørn Olav Hogstad; Appeared in: IEEE Transactions on Information Theory Publication date: Sep 2017, volume: 63, issue:9, pages: 6000 - 6003 Publisher: IEEE
» Asynchronous Multiagent Primal-Dual Optimization
 Abstract:We present a framework for asynchronously solving convex optimization problems over networks of agents which are augmented by the presence of a centralized cloud computer. This framework uses a Tikhonov-regularized primal-dual approach in which the agents update the system's primal variables and the cloud updates its dual variables. To minimize coordination requirements placed upon the system, the times of communications and computations among the agents are allowed to be arbitrary, provided they satisfy mild conditions. Communications from the agents to the cloud are likewise carried out without any coordination in their timing. However, we require that the cloud keeps the dual variable's value synchronized across the agents, and a counterexample is provided that demonstrates that this level of synchrony is indeed necessary for convergence. Convergence rate estimates are provided in both the primal and dual spaces, and simulation results are presented that demonstrate the operation and convergence of the proposed algorithm. Autors: Matthew T. Hale;Angelia Nedić;Magnus Egerstedt; Appeared in: IEEE Transactions on Automatic Control Publication date: Sep 2017, volume: 62, issue:9, pages: 4421 - 4435 Publisher: IEEE
» Asynchronous Networked MPC With ISM for Uncertain Nonlinear Systems
 Abstract:A model-based event-triggered control scheme for nonlinear constrained continuous-time uncertain systems in networked configuration is presented in this paper. It is based on the combined use of model-predictive control (MPC) and integral sliding-mode (ISM) control, and it is oriented to reduce the packet transmission over the network both in the direct path and in the feedback path, in order to avoid network congestion. The key elements of the proposed control scheme are the ISM local control law, the MPC remote controller, a smart sensor, and a smart actuator, both containing a copy of the nominal model of the plant. The role of the ISM control law is to compensate matched uncertainties, without amplifying the unmatched ones. The MPC controller with tightened constraints generates the control component oriented to comply with state and control requirements and is asynchronous since the underlying constrained optimization problem is solved only when a triggering event occurs. In the paper, the robustness properties of the controlled system are theoretically analyzed, proving the regional input-to-state practical stability of the overall control scheme. Autors: Gian Paolo Incremona;Antonella Ferrara;Lalo Magni; Appeared in: IEEE Transactions on Automatic Control Publication date: Sep 2017, volume: 62, issue:9, pages: 4305 - 4317 Publisher: IEEE
» Atom by Atom Simulations of Nanomaterial Manipulation: The Plasma Etching Case
 Abstract:In this paper, we discuss a multiscale method for process simulations with atomic resolution applied to plasma etching. We demonstrate that the accurate prediction of microstructural modifications, as a function of the equipment parameters, can be achieved by coupling two simulation approaches that model phenomena at different length scales. Focusing on the etching processing of nanopatterned silicon samples in HBr/O-type plasma, we highlight the main ingredients of the numerical method: 1) the comprehensive model of plasma reactions to determine the particle distribution of the active plasma components, and 2) a coupled Kinetic Monte-Carlo method simulating all the events concurring to the surface erosion at the atomic level. The technique predicts the variation of the process results when the macroscopic parameters related to equipment settings (e.g., power, potential, and injected gas composition) are modified. A comparison between the microscopic analysis of real structures and the etched profiles predicted by the feature scale simulations validates the coupled numerical approach. Autors: Alessio Campo;Salvatore Francesco Lombardo;Ioannis Deretzis;Giuseppe Garozzo;Giuseppe Gioacchino Neil Angilella;Antonino La Magna; Appeared in: IEEE Transactions on Nanotechnology Publication date: Sep 2017, volume: 16, issue:5, pages: 790 - 797 Publisher: IEEE
» Attenuation of Stray Magnetic Field in Inductive Power Transfer by Controlling Phases of Windings’ Currents
 Abstract:Significant stray magnetic field exists around the inductive-power-transfer (IPT) coils owning to the large gap between transmitter and receiver. In this paper, the field is attenuated by controlling the phases of windings’ currents. The relationship between magnetic field and windings’ currents is analyzed according to the diagrams of phasors. The dual-side-controlled converter is used for circuit realization, in which the inverter and rectifier with MOSFETs bridges are implemented on both the transmitter side and receiver side. The pulsewidths of the voltages for the inverter and rectifier control the currents magnitudes, whereas the phases of the voltages control the currents phases. The effectiveness of field attenuation with this method was verified in both simulation and experiment, for the IPT system with series-series compensation. The stray magnetic field was reduced by up to 30% when the phase difference is 50° between transmitter current and receiver current, compared to the conventional case with passive rectifier when the phase difference is 90°. The increase of winding losses is also analyzed. Autors: Ming Lu;Khai D. T. Ngo; Appeared in: IEEE Transactions on Magnetics Publication date: Sep 2017, volume: 53, issue:9, pages: 1 - 8 Publisher: IEEE
» Audio Identification by Sampling Sub-fingerprints and Counting Matches
 Abstract:It is challenging to retrieve audio clips from large audio datasets not only due to the high dimensionality of audio but also due to the large number of audios. Fingerprinting methods primarily focus on the use of semantic-level techniques to speed up retrieval and neglect low-level support. This paper shows that the performance of audio retrieval can be exploited by properly organizing and manipulating audio fingerprint data. The proposed sampling and counting method markedly improves the retrieval speed while maintaining a high recall rate and high precision for short audio clips. The proposed inverted index structure for fingerprints quickly shrinks the scope of the candidate set while requiring considerably less memory. The experiments show that the proposed method is faster and yields more consistent performance in terms of recall rate and precision than do the state-of-the-art methods. The proposed method is scalable for big audio data and is robust to background noise, resampling, MP3 conversion, white noise addition, bandpass filtering, chorus, echo, flanger, gsm compression, and tremolo. The average precision and recall rates are 99.995% and 99.78%, respectively, for dataset 1 and average 98.97% and 95.15%, respectively, for dataset 2. Specifically, the precision and recall rates for query audio clips of 3 s in length in the targeted dataset 1 are 99.94% and 99.64%, respectively. Autors: Shanshan Yao;Baoning Niu;Jianquan Liu; Appeared in: IEEE Transactions on Multimedia Publication date: Sep 2017, volume: 19, issue:9, pages: 1984 - 1995 Publisher: IEEE
 Abstract:We thank Sinha [1] for bringing this point to our attention and regret that we did not correct some typographical errors in [2], which lead to this comment. A negative sign is missing in the relationship for in [2, eq. (8)]. The correct design equation is \begin{align} Z_{e1} =Z_{0} Z_{e2} \frac {Z_{0} \cos \theta _{2} \pm \sqrt {Z_{0}^{2} -Z_{e2}^{2} \sin ^{2}\theta _{2} +2Z_{0} Z_{e2} \sin \theta _{2} } }{\cot \theta _{1} \big [ {\big ( {Z_{e2}^{2} -Z_{0}^{2} } \big )\sin \theta _{2} -2Z_{0} Z_{e2} } \big ]}.\!\!\notag \!\!\\ {}\end{align} Autors: Mrinal Kanti Mandal;Sudini Reshma; Appeared in: IEEE Microwave and Wireless Components Letters Publication date: Sep 2017, volume: 27, issue:9, pages: 859 - 859 Publisher: IEEE
» Automated Quantitative Bone Analysis in In Vivo X-ray Micro-Computed Tomography
 Abstract:Measurement and analysis of bone morphometry in 3D micro-computed tomography volumes using automated image processing and analysis improve the accuracy, consistency, reproducibility, and speed of preclinical osteological research studies. Automating segmentation and separation of individual bones in 3D micro-computed tomography volumes of murine models presents significant challenges considering partial volume effects and joints with thin spacing, i.e., 50 to . In this paper, novel hybrid splitting filters are presented to overcome the challenge of automated bone separation. This is achieved by enhancing joint contrast using rotationally invariant second-derivative operators. These filters generate split components that seed marker-controlled watershed segmentation. In addition, these filters can be used to separate metaphysis and epiphysis in long bones, e.g., femur, and remove the metaphyseal growth plate from the detected bone mask in morphometric measurements. Moreover, for slice-by-slice stereological measurements of long bones, particularly curved bones, such as tibia, the accuracy of the analysis can be improved if the planar measurements are guided to follow the longitudinal direction of the bone. In this paper, an approach is presented for characterizing the bone medial axis using morphological thinning and centerline operations. Building upon the medial axis, a novel framework is presented to automatically guide stereological measurements of long bones and enhance measurement accuracy and consistency. These image processing and analysis approaches are combined in an automated streamlined software workflow and applied to a range of in vivo micro-computed tomography studies for validation. Autors: Ali Behrooz;Peet Kask;Jeff Meganck;Joshua Kempner; Appeared in: IEEE Transactions on Medical Imaging Publication date: Sep 2017, volume: 36, issue:9, pages: 1955 - 1965 Publisher: IEEE
» Automatic Detection and Classification of High-Frequency Oscillations in Depth-EEG Signals
 Abstract:Goal: Interictal high-frequency oscillations (HFOs [30–600 Hz]) have proven to be relevant biomarkers in epilepsy. In this paper, four categories of HFOs are considered: Gamma ([30–80 Hz]), high-gamma ([80–120 Hz]), ripples ([120–250 Hz]), and fast-ripples ([250–600 Hz]). A universal detector of the four types of HFOs is proposed. It has the advantages of 1) classifying HFOs, and thus, being robust to inter and intrasubject variability; 2) rejecting artefacts, thus being specific. Methods : Gabor atoms are tuned to cover the physiological bands. Gabor transform is then used to detect HFOs in intracerebral electroencephalography (iEEG) signals recorded in patients candidate to epilepsy surgery. To extract relevant features, energy ratios, along with event duration, are investigated. Discriminant ratios are optimized so as to maximize among the four types of HFOs and artefacts. A multiclass support vector machine (SVM) is used to classify detected events. Pseudoreal signals are simulated to measure the performance of the method when the ground truth is known. Results: Experiments are conducted on simulated and on human iEEG signals. The proposed method shows high performance in terms of sensitivity and false discovery rate. Conclusion: The methods have the advantages of detecting and discriminating all types of HFOs as well as avoiding false detections caused by artefacts. Significance: Experimental results show the feasibility of a robust and universal detector. Autors: Nisrine Jrad;Amar Kachenoura;Isabelle Merlet;Fabrice Bartolomei;Anca Nica;Arnaud Biraben;Fabrice Wendling; Appeared in: IEEE Transactions on Biomedical Engineering Publication date: Sep 2017, volume: 64, issue:9, pages: 2230 - 2240 Publisher: IEEE
» Automatic Detection of Wind Turbine Blade Surface Cracks Based on UAV-Taken Images
 Abstract:In this paper, a data-driven framework is proposed to automatically detect wind turbine blade surface cracks based on images taken by unmanned aerial vehicles (UAVs). Haar-like features are applied to depict crack regions and train a cascading classifier for detecting cracks. Two sets of Haar-like features, the original and extended Haar-like features, are utilized. Based on selected Haar-like features, an extended cascading classifier is developed to perform the crack detection through stage classifiers selected from a set of base models, the LogitBoost, Decision Tree, and Support Vector Machine. In the detection, a scalable scanning window is applied to locate crack regions based on developed cascading classifiers using the extended feature set. The effectiveness of the proposed data-driven crack detection framework is validated by both UAV-taken images collected from a commercial wind farm and artificially generated. The extended cascading classifier is compared with a cascading classifier developed by the LogitBoost only to show its advantages in the image-based crack detection. A computational study is performed to further demonstrate the success of the proposed framework in identifying the number of cracks and locating them in original images. Autors: Long Wang;Zijun Zhang; Appeared in: IEEE Transactions on Industrial Electronics Publication date: Sep 2017, volume: 64, issue:9, pages: 7293 - 7303 Publisher: IEEE
» Automatic Ice Surface and Bottom Boundaries Estimation in Radar Imagery Based on Level-Set Approach
 Abstract:Accelerated loss of ice from Greenland and Antarctica has been observed in recent decades. The melting of polar ice sheets and mountain glaciers has considerable influence on sea level rise in a changing climate. Ice thickness is a key factor in making predictions about the future of massive ice reservoirs. The ice thickness can be estimated by calculating the exact location of the ice surface and subglacial topography beneath the ice in radar imagery. Identifying the locations of ice surface and bottom is typically performed manually, which is a very time-consuming procedure. Here, we propose an approach, which automatically detects ice surface and bottom boundaries using distance-regularized level-set evolution. In this approach, the complex topology of ice surface and bottom boundary layers can be detected simultaneously by evolving an initial curve in the radar imagery. Using a distance-regularized term, the regularity of the level-set function is intrinsically maintained, which solves the reinitialization issues arising from conventional level-set approaches. The results are evaluated on a large data set of airborne radar imagery collected during a NASA IceBridge mission over Antarctica and show promising results with respect to manually picked data. Autors: Maryam Rahnemoonfar;Geoffrey Charles Fox;Masoud Yari;John Paden; Appeared in: IEEE Transactions on Geoscience and Remote Sensing Publication date: Sep 2017, volume: 55, issue:9, pages: 5115 - 5122 Publisher: IEEE
» Automatic Skin Lesion Segmentation Using Deep Fully Convolutional Networks With Jaccard Distance
 Abstract:Automatic skin lesion segmentation in dermoscopic images is a challenging task due to the low contrast between lesion and the surrounding skin, the irregular and fuzzy lesion borders, the existence of various artifacts, and various imaging acquisition conditions. In this paper, we present a fully automatic method for skin lesion segmentation by leveraging 19-layer deep convolutional neural networks that is trained end-to-end and does not rely on prior knowledge of the data. We propose a set of strategies to ensure effective and efficient learning with limited training data. Furthermore, we design a novel loss function based on Jaccard distance to eliminate the need of sample re-weighting, a typical procedure when using cross entropy as the loss function for image segmentation due to the strong imbalance between the number of foreground and background pixels. We evaluated the effectiveness, efficiency, as well as the generalization capability of the proposed framework on two publicly available databases. One is from ISBI 2016 skin lesion analysis towards melanoma detection challenge, and the other is the PH2 database. Experimental results showed that the proposed method outperformed other state-of-the-art algorithms on these two databases. Our method is general enough and only needs minimum pre- and post-processing, which allows its adoption in a variety of medical image segmentation tasks. Autors: Yading Yuan;Ming Chao;Yeh-Chi Lo; Appeared in: IEEE Transactions on Medical Imaging Publication date: Sep 2017, volume: 36, issue:9, pages: 1876 - 1886 Publisher: IEEE
» Automatic Welding Seam Tracking and Identification
 Abstract:In the automatic welding process on mid/thick plates, the precision of the welding position has an important effect on welding quality, which mainly relies on the identification of the welding seam. However, due to some possible disturbances in complex unstructured welding environments, e.g., strong arc lights, welding splashes, thermal-induced deformations, etc., it is a great challenge to identify the welding seam. In this paper, we propose a robust automatic welding seam identification and tracking method by utilizing structured-light vision. First, after the preprocessing of the welding image, the gray distribution of the laser stripe is tracked and the profile of the welding seam is searched in a small area by using the Kalman filter, with the aim to avoid some disturbances. Second, in order to extract the welding seam profile, a series of centroids obtained by scanning the columns in the rectangular window are fitted using the least-squares method. Third, a character string method is proposed to qualitatively describe the welding seam profile, which might consist of different segment and junction relationship elements. And then, these character strings acquired from the object image are matched with those from the model, so that the position of the welding seam can be determined. Finally, the advantages of the new algorithm are testified and compared through several experiments. Autors: Xinde Li;Xianghui Li;Shuzhi Sam Ge;Mohammad Omar Khyam;Chaomin Luo; Appeared in: IEEE Transactions on Industrial Electronics Publication date: Sep 2017, volume: 64, issue:9, pages: 7261 - 7271 Publisher: IEEE
» Autonomous Relay for Millimeter-Wave Wireless Communications
 Abstract:Millimeter-wave (mmWave) communication is the rising technology for next-generation wireless transmission. Benefited by its abundant bandwidth and short wavelength, mmWave is advanced in multi-gigabit transmittability and beamforming. In contrast, the short wavelength also makes mmWave easily blocked by obstacles. In order to bypass these obstacles, relays are widely needed in mmWave communications. Unmanned autonomous vehicles (UAVs), such as drones and self-driving robots, enable the mobile relays in real applications. Nevertheless, it is challenging for a UAV to find its optimal relay location automatically. On the one hand, it is difficult to find the location accurately due to the complex and dynamic wireless environment; on the other hand, most applications require the relay to forward data immediately, so the autonomous process should be fast. To tackle this challenge, we propose a novel method AutoRelay specialized for mmWave communications. In AutoRelay, the UAV samples the link qualities of mmWave beams while moving. Based on the real-time sampling, the UAV gradually adjusts its path to approach the optimal location by leveraging compressive sensing theory to estimate the link qualities in candidate space, which increases the accuracy and save the time. Performance results demonstrate that AutoRelay outperforms existing methods in achieving an accurate and efficient relay strategy. Autors: Linghe Kong;Linsheng Ye;Fan Wu;Meixia Tao;Guihai Chen;Athanasios V. Vasilakos; Appeared in: IEEE Journal on Selected Areas in Communications Publication date: Sep 2017, volume: 35, issue:9, pages: 2127 - 2136 Publisher: IEEE
» Autonomous Surveillance Robots: A Decision-Making Framework for Networked Muiltiagent Systems
 Abstract:This article proposes an architecture for an intelligent surveillance system, where the aim is to mitigate the burden on humans in conventional surveillance systems by incorporating intelligent interfaces, computer vision, and autonomous mobile robots. Central to the intelligent surveillance system is the application of research into planning and decision making in this novel context. In this article, we describe the robot surveillance decision problem and explain how the integration of components in our system supports fully automated decision making. Several concrete scenarios deployed in real surveillance environments exemplify both the flexibility of our system to experiment with different representations and algorithms and the portability of our system into a variety of problem contexts. Moreover, these scenarios demonstrate how planning enables robots to effectively balance surveillance objectives, autonomously performing the job of human patrols and responders. Autors: Stefan Witwicki;Jose Carlos Castillo;Joao Messias;Jesus Capitan;Francisco S. Melo;Pedro U. Lima;Manuela Veloso; Appeared in: IEEE Robotics & Automation Magazine Publication date: Sep 2017, volume: 24, issue:3, pages: 52 - 64 Publisher: IEEE
» Autonomous Switched Control of Load Shifting Robot Manipulators
 Abstract:An autonomous switched controller is proposed for a robot manipulator to ensure asymptotical tracking performance in the presence of shifting loads. Since the manipulator parameter jumps along with the load shift, the manipulator is modeled as a switched system whose switching signal depicts the load change. When the load change is not detectable, the switching signal of the switched system is unavailable. In this case, another “autonomous” switching law is designed for the given subcontrollers using a switched reset supervisory variable. Asymptotic tracking is ensured for slow load shifting. The effectiveness of the proposed method is verified by both simulations of a 2-DOF robot manipulator and experiments of a closed-chain five-bar robot. Autors: Xia Wang;Jun Zhao; Appeared in: IEEE Transactions on Industrial Electronics Publication date: Sep 2017, volume: 64, issue:9, pages: 7161 - 7170 Publisher: IEEE
» Backward-Wave Oscillator Operating in Low Magnetic Fields Using a Hybrid-TE11 Mode
 Abstract:We present the design of a backward-wave oscillator based on a novel slow-wave structure (SWS) operating under low magnetic field conditions (<0.2 T). The design features a high-power electron beam interacting in dual synchronism with TM01 and hybrid TE11 modes. By exploiting mode control techniques, low magnetic fields with asymmetrical beam trajectories, a dominant interaction with the higher frequency hybrid TE11 mode is established. We present a design of the full interaction circuit, which also features a compact mode converter and an output coupler to produce a TE01 mode at the dual rectangular waveguide output. Simulations with a high-frequency structural simulator demonstrate dual-mode backward wave synchronism. A quantitative analysis of the electric field profiles is also presented. We also use a particle-in-cell (PIC) solver to predict the SWS performance under hot-test facility specific conditions. Using a 490-kV, 84-A electron beam under a guiding magnetic field of 0.15 T, PIC simulations predict an output power of 18 MW at 5 GHz with a peak power efficiency of 44%. Autors: Ushemadzoro Chipengo;Niru K. Nahar;John L. Volakis; Appeared in: IEEE Transactions on Electron Devices Publication date: Sep 2017, volume: 64, issue:9, pages: 3863 - 3869 Publisher: IEEE
» Balanced Mixture of Deformable Part Models With Automatic Part Configurations
 Abstract:This paper presents a method to improve the traditional mixture of deformable part models (MDPM) method from the learning perspective. First, an object part configuration learning algorithm based on group sparsity constraint is introduced to automatically discover the object part number, size, and location. The algorithm imposes two additional regularization terms in addition to the standard hinge loss function. The first term focuses on automatic part selection and the second term focuses on automatic part placement. Second, this paper introduces an improved MDPM training framework. The framework applies a learned transformation to normalize the prediction score from each individual deformable part model (DPM) into a pseudo probability such that the partition of the entire object appearance feature space becomes less sensitive to the prior distributions of different DPMs. Finally, the two proposed improvements are combined and formulated under the expectation-maximization framework. We evaluate our method mainly using the PASCAL VOC2007 and VOC2010 detection benchmarks and show that the proposed learning algorithms could increase the detection mean AP score by 2.4% and 0.9%, respectively, on these two data sets when using the proposed part selection method and the training algorithm. We also present further in-depth analysis of the proposed algorithm in the experiments. Autors: De Cheng;Yihong Gong;Jingjun Wang;Nanning Zheng; Appeared in: IEEE Transactions on Circuits and Systems for Video Technology Publication date: Sep 2017, volume: 27, issue:9, pages: 1962 - 1973 Publisher: IEEE
» Balancing Energy Efficiency and Device Lifetime in TWDM-PON Under Traffic Fluctuations
 Abstract:Energy-efficient time- and wavelength-division multiplexed passive optical network has been intensely investigated. However, conventional schemes aimed at energy efficiency may bring about repeated power-state transitions between sleep mode and active mode, resulting in periodic device-temperature cycling and frequent wavelength reassignment, which will greatly deteriorate network quality of service. These side effects become non-trivial when traffic fluctuates sharply as expected in the future. In this letter, we propose a wavelength-postponed-switching-off (WPS) strategy to reduce power-state transitions by means of postponing the power-off of redundant wavelengths. Redundant wavelengths represent wavelengths that are supposed to be powered off by conventional schemes when traffic declines. Illustrative results show that, the WPS strategy can provide a balanced performance of both energy efficiency and device lifetime, while decreasing service interruption caused by turning ON or OFF the equipment. Autors: Jialong Li;Zhizhen Zhong;Nan Hua;Xiaoping Zheng;Bingkun Zhou; Appeared in: IEEE Communications Letters Publication date: Sep 2017, volume: 21, issue:9, pages: 1981 - 1984 Publisher: IEEE
» Band Offset Enhancement of a-Al2O3/Tensile-Ge for High Mobility Nanoscale pMOS Devices
 Abstract:The band alignment properties of amorphous Al2O3 on strain-engineered biaxial tensile-strained epitaxial Ge, grown in situ by molecular beam epitaxy on InxGa1–xAs virtual substrates, are presented. X-ray photoelectron spectroscopy investigation demonstrated an increase in the valence band offset of the Al2O3/strained Ge system with increasing tensile strain. For Ge strain-states of 1.14%, 1.6%, and 1.94%, the corresponding valence band offsets were found to be 4.43 ± 0.1 eV, 3.95 ± 0.1 eV, and 4.55 ± 0.1 eV, respectively, demonstrating a ~0.8 eV increase as compared with Ge grown on GaAs. The observed enhancement in the valence band discontinuity between tensile-strained Ge and Al2O3 offers a unique and novel path for the simultaneous improvement of hole mobility (via strain) and hole confinement (via a larger valence band offset) in future low-power and high-performance Ge-based nanoscale pMOS devices. Autors: Michael B. Clavel;Mantu K. Hudait; Appeared in: IEEE Electron Device Letters Publication date: Sep 2017, volume: 38, issue:9, pages: 1196 - 1199 Publisher: IEEE
» Band Subset Selection for Anomaly Detection in Hyperspectral Imagery
 Abstract:This paper presents a new approach, called band subset selection (BSS)-based hyperspectral anomaly detection (AD), which selects multiple bands simultaneously as a band subset rather than selecting multiple bands one at a time as the tradition band selection (BS) does, referred to as sequential multiple BS (SQMBS). Its idea is to first use virtual dimensionality (VD) to determine the number of multiple bands, needed to be selected as a band subset and then develop two iterative process, sequential BSS (SQ-BSS) algorithm and successive BSS (SC-BSS) algorithm to find an optimal band subset numerically among all possible combinations out of the full band set. In order to terminate the search process the averaged least-squares error (ALSE) and 3-D receiver operating characteristic (3D ROC) curves are used as stopping criteria to evaluate performance relative to AD using the full band set. Experimental results demonstrate that BSS generally performs better background suppression while maintaining target detection capability compared to target detection using full band information. Autors: Lin Wang;Chein-I Chang;Li-Chien Lee;Yulei Wang;Bai Xue;Meiping Song;Chuanyan Yu;Sen Li; Appeared in: IEEE Transactions on Geoscience and Remote Sensing Publication date: Sep 2017, volume: 55, issue:9, pages: 4887 - 4898 Publisher: IEEE
» Basis Expansion Approaches for Regularized Sequential Dictionary Learning Algorithms With Enforced Sparsity for fMRI Data Analysis
 Abstract:Sequential dictionary learning algorithms have been successfully applied to functional magnetic resonance imaging (fMRI) data analysis. fMRI data sets are, however, structured data matrices with the notions of temporal smoothness in the column direction. This prior information, which can be converted into a constraint of smoothness on the learned dictionary atoms, has seldomly been included in classical dictionary learning algorithms when applied to fMRI data analysis. In this paper, we tackle this problem by proposing two new sequential dictionary learning algorithms dedicated to fMRI data analysis by accounting for this prior information. These algorithms differ from the existing ones in their dictionary update stage. The steps of this stage are derived as a variant of the power method for computing the SVD. The proposed algorithms generate regularized dictionary atoms via the solution of a left regularized rank-one matrix approximation problem where temporal smoothness is enforced via regularization through basis expansion and sparse basis expansion in the dictionary update stage. Applications on synthetic data experiments and real fMRI data sets illustrating the performance of the proposed algorithms are provided. Autors: Abd-Krim Seghouane;Asif Iqbal; Appeared in: IEEE Transactions on Medical Imaging Publication date: Sep 2017, volume: 36, issue:9, pages: 1796 - 1807 Publisher: IEEE
» BASS Net: Band-Adaptive Spectral-Spatial Feature Learning Neural Network for Hyperspectral Image Classification
 Abstract:Deep learning based land cover classification algorithms have recently been proposed in the literature. In hyperspectral images (HSIs), they face the challenges of large dimensionality, spatial variability of spectral signatures, and scarcity of labeled data. In this paper, we propose an end-to-end deep learning architecture that extracts band specific spectral-spatial features and performs land cover classification. The architecture has fewer independent connection weights and thus requires fewer training samples. The method is found to outperform the highest reported accuracies on popular HSI data sets. Autors: Anirban Santara;Kaustubh Mani;Pranoot Hatwar;Ankit Singh;Ankur Garg;Kirti Padia;Pabitra Mitra; Appeared in: IEEE Transactions on Geoscience and Remote Sensing Publication date: Sep 2017, volume: 55, issue:9, pages: 5293 - 5301 Publisher: IEEE
» Bay Area Rapid Transit Extension South on the East Bay [Transportation Systems]
 Abstract:San Francisco's Bay Area Rapid Transit (BART) Warm Springs Extension opened for service on Saturday, 25 March 2017. The 5.4-mi extension connects the existing Fremont Station to the new Warm Springs/South Fremont Station. Autors: Harvey Glickenstein; Appeared in: IEEE Vehicular Technology Magazine Publication date: Sep 2017, volume: 12, issue:3, pages: 12 - 16 Publisher: IEEE
» Bayesian Learning for Dynamic Feature Extraction With Application in Soft Sensing
 Abstract:Data-driven techniques such as principal component analysis (PCA) have been widely used to derive predictive models from historical data and applied for quality prediction in industry. Motivated by reducing data collinearity and extracting informative driving forces behind data, latent variable models are explored to facilitate the prediction by regressing data on a set of extracted features. In this paper, a novel learning strategy is proposed to build dynamic features under a full Bayesian framework, incorporating data information and prior knowledge of process dynamics. Unlike the traditional PCA that extracts features based on variances explained, in this paper, the latent features are extracted with the guidance of preferred velocities of nominal variations. By applying Bayesian learning algorithms, parameters are estimated with probability distributions accounting for corresponding uncertainties, and the number of latent features can be automatically determined by the variational Bayesian inference algorithm. The effectiveness and practicability of this Bayesian dynamic feature regression are demonstrated through simulated examples as well as an industrial case study. Autors: Yanjun Ma;Biao Huang; Appeared in: IEEE Transactions on Industrial Electronics Publication date: Sep 2017, volume: 64, issue:9, pages: 7171 - 7180 Publisher: IEEE
» Bayesian Optimal Data Detector for mmWave OFDM System With Low-Resolution ADC
 Abstract:Orthogonal frequency division multiplexing (OFDM) has been widely used in communication systems operating in the millimeter wave (mmWave) band to combat frequency-selective fading and achieve multi-Gbps transmissions, such as the IEEE 802.15.3c and the IEEE 802.11ad. For mmWave systems with ultra high sampling rate requirements, the use of low-resolution analog-to-digital converters (ADCs) (i.e., 1–3 bits) ensures an acceptable level of power consumption and system costs. However, orthogonality among subchannels in the OFDM system cannot be maintained because of the severe nonlinearity caused by low-resolution ADC, which renders the design of data detector challenging. In this paper, we develop an efficient algorithm for optimal data detection in the mmWave OFDM system with low-resolution ADCs. The analytical performance of the proposed detector is derived and verified to achieve the fundamental limit of the Bayesian optimal design. On the basis of the derived analytical expression, we further propose a power allocation (PA) scheme that seeks to minimize the average symbol error rate. In addition to the optimal data detector, we also develop a feasible channel estimation method, which can provide high-quality channel state information without significant pilot overhead. Simulation results confirm the accuracy of our analysis and illustrate that the performance of the proposed detector in conjunction with the proposed PA scheme is close to the optimal performance of the OFDM system with infinite-resolution ADC. Autors: Hanqing Wang;Chao-Kai Wen;Shi Jin; Appeared in: IEEE Journal on Selected Areas in Communications Publication date: Sep 2017, volume: 35, issue:9, pages: 1962 - 1979 Publisher: IEEE
» Beamforming Optimization for Full-Duplex Wireless-Powered MIMO Systems
 Abstract:We propose techniques for optimizing transmit beamforming in a full-duplex multiple-input-multiple-output wireless-powered communication system, which consists of two phases. In the first phase, the wireless-powered mobile station (MS) harvests energy using signals from the base station (BS), whereas in the second phase, both MS and BS communicate to each other in a full-duplex mode. When complete instantaneous channel state information (CSI) is available, the BS beamformer and the time-splitting (TS) parameter of energy harvesting are jointly optimized in order to obtain the BS–MS rate region. The joint optimization problem is non-convex, however, a computationally efficient optimum technique, based upon semidefinite relaxation and line-search, is proposed to solve the problem. A sub-optimum zero-forcing approach is also proposed, in which a closed-form solution of TS parameter is obtained. When only the second-order statistics of transmit CSI is available, we propose to maximize the ergodic information rate at the MS while maintaining the outage probability at the BS below a certain threshold. An upper bound for the outage probability is also derived and an approximate convex optimization framework is proposed for efficiently solving the underlying non-convex problem. Simulations demonstrate the advantages of the proposed methods over the sub-optimum and half-duplex ones. Autors: Batu Krishna Chalise;Himal A. Suraweera;Gan Zheng;George K. Karagiannidis; Appeared in: IEEE Transactions on Communications Publication date: Sep 2017, volume: 65, issue:9, pages: 3750 - 3764 Publisher: IEEE
» Benchmarking Si, SiGe, and III–V/Si Hybrid SIS Optical Modulators for Datacenter Applications
 Abstract:Recently, Si-photonics received a growing interest and started to move from laboratories to industrial product development, mainly for the applications inside data-centers. One of the weaknesses of Si is its relatively low plasma dispersion efficiency, making the size of phase modulator large. This efficiency can be improved by using the heterogeneous integration of material such as InP, InGaAsP, or SiGe to fabricate hybrid semiconductor–insulator–semiconductor (SIS) optical phase modulators. At the same time, the standard figure of merit for modulator benchmarking does not consider the dynamic behavior of the SIS devices, nor is making the link with the system level specifications such as optical modulation amplitude (OMA), widely used in 100G to 400G parallel single mode or coarse wavelength division multiplexing applications. In this paper, we propose to simply link the modulator performance to the OMA, to derive a compact model for SIS devices and to compare hybrid device performances for various materials. Autors: Frederic Boeuf;Jae-Hoon Han;Shinichi Takagi;Mitsuru Takenaka; Appeared in: Journal of Lightwave Technology Publication date: Sep 2017, volume: 35, issue:18, pages: 4047 - 4055 Publisher: IEEE
» BER Analysis of SCMA Systems With Codebooks Based on Star-QAM Signaling Constellations
 Abstract:In this letter, the average bit error rate (BER) performance of sparse code multiple access (SCMA) systems with codebooks based on star quadrature amplitude modulation (star-QAM) signaling constellations over the additive white Gaussian noise channel is analyzed and evaluated. Motivated by the fact that the phase rotation plays an important role in designing codebooks and thus can significantly affect the BER performance in SCMA system, we derive a theoretical expression for the BER performance based on the statistics of the phase angle in SCMA constellations. Numerical and simulation results corroborate the proposed analysis. Autors: Lisu Yu;Pingzhi Fan;Xianfu Lei;P. Takis Mathiopoulos; Appeared in: IEEE Communications Letters Publication date: Sep 2017, volume: 21, issue:9, pages: 1925 - 1928 Publisher: IEEE
» Beyond 200G Direct Detection Transmission With Nyquist Asymmetric Twin-SSB Signal at C-Band
 Abstract:For short reach and metro applications, single sideband (SSB) is a promising scheme due to its high spectral efficiency and tolerance to chromatic dispersion. In this study, we propose a novel asymmetric twin-SSB scheme based on Nyquist pulse shaping. Without joint equalization, the two sidebands can be separately detected with a small guard band. We experimentally demonstrate 224-Gb/s 16-ary quadrature amplitude modulation (16-QAM) asymmetric twin-SSB transmission with direct detection. After 240-km standard single mode fiber (SSMF) transmission, the bit error rates (BERs) of the right-sideband (RSB) and the left-sideband (LSB) are 3.2 × 10-3 and 2.8 × 10-3, respectively, which are below the 7% hard-decision forward error correction (HD-FEC) threshold of 3.8 × 10-3. The net bitrate is 203.7 Gb/s with consideration of both frame redundancy and HD-FEC overhead. To our best knowledge, we report the longest transmission distance for 200G single wavelength and single polarization direct detection systems. The advantages of the asymmetric twin-SSB scheme over the symmetric scheme are discussed through simulating the crosstalk resistance of both two schemes. We also demonstrate 300-Gb/s 32-QAM transmission over 80-km SSMF. The BERs of RSB and LSB are 1.50 × 10-2 and 1.61 × 10-2, respectively, which are below the 15% soft-decision forward error correction (SD-FEC) threshold of 1.8 × 10-2. The net bitrate is 254.3 Gb/s with consideration of both frame redundancy and SD-FEC overhead. To our best knowledge, it is the maximum bitrate ever reported for C-band 80-km single wavelength and single polarization direct detection transmission. The proposed scheme provides a useful and low-cost solution for high speed datacenter interconnection and metro-scale transmission. Autors: Yixiao Zhu;Xiaoke Ruan;Kaiheng Zou;Fan Zhang; Appeared in: Journal of Lightwave Technology Publication date: Sep 2017, volume: 35, issue:17, pages: 3629 - 3636 Publisher: IEEE
» Big Search in Cyberspace
 Abstract:With the rapid development of big data analytics, mobile computing, Internet of Things, cloud computing, and social networking, cyberspace has expanded to a cross-fused and ubiquitous space made up of human beings, things, and information. Internet applications have evolved from Web 1.0 to Web 2.0 and Web 3.0, and web information has seen an explosive growth, which is strongly promoting the advent of a global era of big data. In this ubiquitous cyberspace, traditional search engines can no longer fully satisfy the evolving needs of various types of users. Therefore, search engines must make completely innovative, revolutionary changes for the next generation of search, which is referred to as “big search”. This paper first studies the development needs of big search. Then, big search is defined, and the 5S properties (Sourcing, Sensing, Synthesizing, Solution, and Security) of big search, which are different from those of traditional search engines, are elaborated. Also, the paper provides a system architecture for big search, explores the key technologies that support the 5S properties, and describes potential application fields of big search technology. Finally, the research opportunities of big search are discussed. Autors: Binxing Fang;Yan Jia;Xiaoyong Li;Aiping Li;Xindong Wu; Appeared in: IEEE Transactions on Knowledge and Data Engineering Publication date: Sep 2017, volume: 29, issue:9, pages: 1793 - 1805 Publisher: IEEE
» Binary and Multi-Class Learning Based Low Complexity Optimization for HEVC Encoding
 Abstract:High Efficiency Video Coding (HEVC) improves the compression efficiency at the cost of high computational complexity by using the quad-tree coding unit (CU) structure and variable prediction unit (PU) modes. To minimize the HEVC encoding complexity while maintaining its compression efficiency, a binary and multi-class support vector machine (SVM)-based fast HEVC encoding algorithm is presented in this paper. First, the processes of recursive CU decision and PU selection in HEVC are modeled as hierarchical binary classification and multi-class classification structures. Second, according to the two classification structures, the CU decision and PU selection are optimized by binary and multi-class SVM, i.e., the CU and PU can be predicted directly via classifiers without intensive rate distortion (RD) cost calculation. In particular, to achieve better prediction performance, a learning method is proposed to combine the off-line machine learning (ML) mode and on-line ML mode for classifiers based on a multiple reviewers system. Additionally, the optimal parameters determination scheme is adopted for flexible complexity allocation under a given RD constraint. Experimental results show that the proposed method can achieve 68.3%, 67.3%, and 65.6% time saving on average while the values of Bjøntegaard delta peak signal-to-noise ratio are −0.093dB, −0.091dB, and −0.094dB and the values of Bjøntegaard delta bit rate are 4.191%, 3.842%, and 3.665% under low delay main, low delay main, and random access configurations, respectively, when compared with the HEVC test model version HM 16.5. Meanwhile, the proposed method outperforms the state-of-the-art fast coding algorithms in terms of complexity- reduction and RD performance. Autors: Linwei Zhu;Yun Zhang;Zhaoqing Pan;Ran Wang;Sam Kwong;Zongju Peng; Appeared in: IEEE Transactions on Broadcasting Publication date: Sep 2017, volume: 63, issue:3, pages: 547 - 561 Publisher: IEEE
» Biocomputer and memory built inside living bacteria [News]
 Abstract:Scientists have come up with two clever new ways to harness the programming power of DNA in living bacterial cells. In separate experiments published in Nature in July, researchers reported that they had successfully archived a movie and built a complex biological computer inside living E. coli cells. The experiments expand our ability to exploit DNA's encoding potential. "What these papers represent is just how good we are getting at harnessing that power," says Julius Lucks, a bioengineer at the Center for Synthetic Biology, at Northwestern University, in Evanston, Ill., who was not involved in either report. Autors: Emily Waltz; Appeared in: IEEE Spectrum Publication date: Sep 2017, volume: 54, issue:9, pages: 11 - 12 Publisher: IEEE
» Biofeedback for Gait Retraining Based on Real-Time Estimation of Tibiofemoral Joint Contact Forces
 Abstract:Biofeedback assisted rehabilitation and intervention technologies have the potential to modify clinically relevant biomechanics. Gait retraining has been used to reduce the knee adduction moment, a surrogate of medial tibiofemoral joint loading often used in knee osteoarthritis research. In this paper, we present an electromyogram-driven neuromusculoskeletal model of the lower-limb to estimate, in real-time, the tibiofemoral joint loads. The model included 34 musculotendon units spanning the hip, knee, and ankle joints. Full-body inverse kinematics, inverse dynamics, and musculotendon kinematics were solved in real-time from motion capture and force plate data to estimate the knee medial tibiofemoral contact force (MTFF). We analyzed five healthy subjects while they were walking on an instrumented treadmill with visual biofeedback of their MTFF. Each subject was asked to modify their gait in order to vary the magnitude of their MTFF. All subjects were able to increase their MTFF, whereas only three subjects could decrease it, and only after receiving verbal suggestions about possible gait modification strategies. Results indicate the important role of knee muscle activation patterns in modulating the MTFF. While this paper focused on the knee, the technology can be extended to examine the musculoskeletal tissue loads at different sites of the human body. Autors: Claudio Pizzolato;Monica Reggiani;David J. Saxby;Elena Ceseracciu;Luca Modenese;David G. Lloyd; Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering Publication date: Sep 2017, volume: 25, issue:9, pages: 1612 - 1621 Publisher: IEEE
» Biologically Inspired Two-Stage Resource Management for Machine-Type Communications in Cellular Networks
 Abstract:Cellular technology has the potential to support large numbers of machine-type communications (MTC) devices for a variety of applications in fifth generation wireless systems. As MTC devices are a recent addition to cellular networks, a major concern is how to effectively manage and limit cellular resources for MTC data transmission without degrading traditional human-type communications (HTC) performance. To tackle this problem, a two-stage resource management framework is proposed with the goal of maintaining traffic equilibrium. In the first stage, an ecological prey-predator model is introduced to model the resource partition for the two types of devices. The steady-state properties of the traffic are analyzed, and the value regions of the allocated MTC resources for stable equilibrium points are derived. In the second stage, given an appropriate resource partition for MTC traffic, these devices are grouped based on their buffer conditions. The optimal resource allocation solution is derived so that the MTC traffic is stable. It is shown that to maintain MTC traffic stability, the resources can be allocated to only two groups. Furthermore, results are presented which show that HTC and MTC traffic can maintain a stable equilibrium using the two-stage resource management framework. Autors: Zebing Feng;Zhiyong Feng;T. Aaron Gulliver; Appeared in: IEEE Transactions on Wireless Communications Publication date: Sep 2017, volume: 16, issue:9, pages: 5897 - 5910 Publisher: IEEE
» Biometric Surveillance and the Right to Privacy [Commentary]
 Abstract: Autors: Angus Willoughby; Appeared in: IEEE Technology and Society Magazine Publication date: Sep 2017, volume: 36, issue:3, pages: 41 - 45 Publisher: IEEE
» Bipolar Intracardiac Electrogram Active Interval Extraction During Atrial Fibrillation
 Abstract:Objective: We introduce novel methods to identify the active intervals (AIs) of intracardiac electrograms (IEGMs) during complex arrhythmias, such as atrial fibrillation (AF). Methods: We formulate the AI extraction problem, which consists of estimating the beginning and duration of the AIs, as a sequence of hypothesis tests. In each test, we compare the variance of a small portion of the bipolar IEGM with its adjacent segments. We propose modified general-likelihood ratio (MGLR) and separating-function-estimation tests; we derive five test statistics (TSs), and show that the AIs can be obtained by threshold crossing the TSs. We apply the proposed methods to the IEGM segments collected from the left atrium of 16 patients (62.4 8.2-years old, four females, four paroxysmal, and twelve persistent AF) prior to catheter ablation. The accuracy of our methods is evaluated by comparing them with previously developed methods and manual annotation (MA). Results: Our results show a high level of similarity between the AIs of the proposed methods and MA, e.g., the true and false positive rates of one of the MGLR-based methods were, respectively, 97.8% and 1.4%. The mean absolute error from estimation of the onset and end of AIs and also for the estimation of the mean cycle length for that approach was 8.7 10.5, 13 15.5, and 4.2 9.4 ms, respectively. Conclusion: The proposed methods can accurately identify onset and duration of AI of the IEGM during AF. Significance: The proposed methods can be used for real-time automated analysis of A- , the most challenging complex arrhythmia. Autors: Mohammad Hassan Shariat;Saeed Gazor;Damian P. Redfearn; Appeared in: IEEE Transactions on Biomedical Engineering Publication date: Sep 2017, volume: 64, issue:9, pages: 2122 - 2133 Publisher: IEEE
» Bit-Level Probabilistically Shaped Coded Modulation
 Abstract:A routine to parallelize and increase the throughput of fixed length distribution matching with non-binary output alphabet is presented. The routine performs parallel distribution matchings with binary output alphabets, and then maps the binary output streams to symbols from the primary, non-binary alphabet. Fixed length distribution matching is essential for probabilistically shaped coded modulation (PSCM), such as the probabilistic amplitude shaping (PAS). In the PAS setup, the novel bit-level distribution matcher achieves similar rate-versus-SNR performance as the symbol-level constant composition distribution matcher, thus providing a high throughput solution for PSCM. Autors: Marcin Pikus;Wen Xu; Appeared in: IEEE Communications Letters Publication date: Sep 2017, volume: 21, issue:9, pages: 1929 - 1932 Publisher: IEEE
» BLASST: Band Limited Atomic Sampling With Spectral Tuning With Applications to Utility Line Noise Filtering
 Abstract:Objective: In this paper, we present and test a new method for the identification and removal of nonstationary utility line noise from biomedical signals. Methods: The method, band limited atomic sampling with spectral tuning (BLASST), is an iterative approach that is designed to 1) fit nonstationarities in line noise by searching for best-fit Gabor atoms at predetermined time points, 2) self-modulate its fit by leveraging information from frequencies surrounding the target frequency, and 3) terminate based on a convergence criterion obtained from the same surrounding frequencies. To evaluate the performance of the proposed algorithm, we generate several simulated and real instances of nonstationary line noise and test BLASST along with alternative filtering approaches. Results: We find that BLASST is capable of fitting line noise well and/or preserving local signal features relative to tested alternative filtering techniques. Conclusion: BLASST may present a useful alternative to bandpass, notch, or other filtering methods when experimentally relevant features have significant power in a spectrum that is contaminated by utility line noise, or when the line noise in question is highly nonstationary. Significance: This is of particular significance in electroencephalography experiments, where line noise may be present in the frequency bands of neurological interest and measurements are typically of low enough strength that induced line noise can dominate the recorded signals. In conjunction with this paper, the authors have released a MATLAB toolbox that performs BLASST on real, vector-valued signals (available at https://github.com/VisLab/blasst). Autors: Kenneth Ray Ball;W. David Hairston;Piotr J. Franaszczuk;Kay A. Robbins; Appeared in: IEEE Transactions on Biomedical Engineering Publication date: Sep 2017, volume: 64, issue:9, pages: 2276 - 2287 Publisher: IEEE
» BLE-Backscatter: Ultralow-Power IoT Nodes Compatible With Bluetooth 4.0 Low Energy (BLE) Smartphones and Tablets
 Abstract:Backscatter communication promises significant power and complexity advantages for Internet of Things devices such as radio frequency identification (RFID) tags and wireless sensor nodes. One perceived disadvantage of backscatter communication has been the requirement for specialized hardware such as RFID readers to receive backscatter signals. In this paper, we show how backscatter signals can be designed for compatibility with the Bluetooth 4.0 low energy (BLE) chipsets already present in billions of smart phones and tablets. We present a prototype microcontroller-based “BLE-Backscatter” tag that produces bandpass frequency-shift keying modulation at 1 Mb/s, enabling compatibility with conventional BLE advertising channels. Using a +23-dBm equivalent isotropically radiated power continuous wave (CW) carrier source, we demonstrate a range of up to 13 m between the tag and an unmodified Apple iPad Mini as well as a PC with the Nordic Semiconductor nRF51822 chipset. With the tag 1 m from the receiver, we demonstrate a range of up to 30 m between the CW carrier source and the tag. In both cases, the existing Bluetooth stack was used, with no modifications whatsoever to hardware, firmware, or software. The backscatter tag consumes only 1.56 nJ/b, over less than the lowest power commercial Bluetooth transmitters. Autors: Joshua F. Ensworth;Matthew S. Reynolds; Appeared in: IEEE Transactions on Microwave Theory and Techniques Publication date: Sep 2017, volume: 65, issue:9, pages: 3360 - 3368 Publisher: IEEE
» Blind Source Separation of Event-Related EEG/MEG
 Abstract:Objective: Blind source separation (BSS) can be used to decompose complex electroencephalography (EEG) or magnetoencephalography data into simpler components based on statistical assumptions without using a physical model. Applications include brain–computer interfaces, artifact removal, and identifying parallel neural processes. We wish to address the issue of applying BSS to event-related responses, which is challenging because of nonstationary data. Methods: We introduce a new BSS approach called momentary-uncorrelated component analysis (MUCA), which is tailored for event-related multitrial data. The method is based on approximate joint diagonalization of multiple covariance matrices estimated from the data at separate latencies. We further show how to extend the methodology for autocovariance matrices and how to apply BSS methods suitable for piecewise stationary data to event-related responses. We compared several BSS approaches by using simulated EEG as well as measured somatosensory and transcranial magnetic stimulation (TMS) evoked EEG. Results: Among the compared methods, MUCA was the most tolerant one to noise, TMS artifacts, and other challenges in the data. With measured somatosensory data, over half of the estimated components were found to be similar by MUCA and independent component analysis. MUCA was also stable when tested with several input datasets. Conclusion: MUCA is based on simple assumptions, and the results suggest that MUCA is robust with nonideal data. Significance: Event-related responses and BSS are valuable and popular tools in neuroscience. Correctly designed BSS is an efficient way of identifying artifactual and neural processes from nonstationary event-related data. Autors: Johanna Metsomaa;Jukka Sarvas;Risto Juhani Ilmoniemi; Appeared in: IEEE Transactions on Biomedical Engineering Publication date: Sep 2017, volume: 64, issue:9, pages: 2054 - 2064 Publisher: IEEE
» Blocker-Tolerant and High-Sensitivity $\Delta \Sigma$ Correlation Digitizer for Radar and Coherent Receiver Applications
 Abstract:In this paper, a coherent subsampling digitizer for pulsed Doppler radar systems is proposed. Prior to transmission, the radar system modulates the RF pulse with a known pseudorandom binary phase shift keying (BPSK) sequence. Upon reception, the radar digitizer uses a programmable sample-and-hold circuit to multiply the received waveform by a properly time-delayed version of the known a priori BPSK sequence. This operation demodulates the desired echo signal while suppressing the spectrum of all in-band noncorrelated interferers, making them appear as noise in the frequency domain. The resulting demodulated narrowband Doppler waveform is then subsampled at the IF frequency by a delta–sigma modulator. Because the digitization bandwidth within the delta–sigma feedback loop is much less than the input bandwidth to the digitizer, the thermal noise outside of the Doppler bandwidth is effectively filtered prior to quantization, providing an increase in signal-to-noise ratio (SNR) at the digitizer’s output compared with the input SNR. In this demonstration, a delta–sigma correlation digitizer is fabricated in a 0.18- CMOS technology. The digitizer has a power consumption of 1.12 mW with an IIP3 of 7.5 dBm. The digitizer is able to recover Doppler tones in the presence of blockers up to 40 dBm greater than the Doppler tone. Autors: John S. Mincey;Jose Silva-Martinez;Aydin Ilker Karşılayan;Christopher T. Rodenbeck; Appeared in: IEEE Transactions on Microwave Theory and Techniques Publication date: Sep 2017, volume: 65, issue:9, pages: 3453 - 3463 Publisher: IEEE
» Bluefin tuna: Fast, but maybe not fast enough [Numbers Don't Lie]
 Abstract:CONSIDER THE TUNA: ITS NEAR-PERFECT HYDRODYNAMICS and efficient propulsion, powered by warm-blooded muscles deep within the body, make it an outstanding swimmer. The largest ones top 70 kilometers per hour, or around 40 knots-fast for a powerboat, and far faster than any known submarine. . But their size and tasty meatiness have put the most majestic of these fish on the road to extinction. The white meat you get in cans comes from the relatively abundant albacore, a small fish, typically less than 40 kilograms (red canned meat comes from the abundant skipjack, another small tuna). In contrast, bluefin (in Japanese, maguro or hon maguro, true tuna) has always been the rarest tuna. Adults can grow to more than 3 meters and weigh more than 600 kg. Autors: Vaclav Smil; Appeared in: IEEE Spectrum Publication date: Sep 2017, volume: 54, issue:9, pages: 24 - 24 Publisher: IEEE
» Bluetooth Data in an Urban Context: Retrieving Vehicle Trajectories
 Abstract:Bluetooth sensors have recently been developed throughout the world for traffic information gathering. Primarily designed for travel time analysis, this article presents a method for vehicular trajectories retrieval. After a short description of some of the challenges at hand in using Bluetooth data in an urban network, a procedure to extract trip information from such data is proposed. It is further analyzed and illustrated at work on a real dataset collected in Brisbane. Last, this article shows that using spatially constrained shortest path analysis, this trip information, once extracted, can be used for the reconstruction of the trajectories. The performance of the process is assessed using both a simulated dataset and one from the real-world acquired in Brisbane, showing encouraging results, with up to 84% of accurately recovered trajectories. Autors: Gabriel Michau;Alfredo Nantes;Ashish Bhaskar;Edward Chung;Patrice Abry;Pierre Borgnat; Appeared in: IEEE Transactions on Intelligent Transportation Systems Publication date: Sep 2017, volume: 18, issue:9, pages: 2377 - 2386 Publisher: IEEE
» Book Reviews [7 Reviews]
 Abstract:The following books are reviewed: Computational Intelligence Applications in Smart Grids by A.F. Zobaa and A. Vaccaro; Tailoring of Nanocomposite Dielectrics by T. Tanaka and A.S. Vaughan; Smart Microgrids-Lessons from Campus Microgrid Design and Implementation by H. Farhangi; Principles and Applications of Ubiquitous Sensing by W. Dargie; Understanding Symmetrical Components for Power System Modeling by J.C. Das; Internet of Things and Data Analytics Handbook by H. Geng; Physics of Digital Photography by A. Rowlands Autors: John J. Shea; Appeared in: IEEE Electrical Insulation Magazine Publication date: Sep 2017, volume: 33, issue:5, pages: 56 - 59 Publisher: IEEE
» Booze-sniffing electronic nose showcases 3D nanosystems [News]
 Abstract:You'd think computers spend most of their time and energy doing...well, computation. But that's not the case: About 90 percent of a computer's execution time and electrical energy is spent transferring data between processing and memory, says Subhasish Mitra, a computer scientist at Stanford University. Even if Moore's Law continued indefinitely, computers would still be limited by this memory bottleneck. Autors: Katherine Bourzac; Appeared in: IEEE Spectrum Publication date: Sep 2017, volume: 54, issue:9, pages: 14 - 14 Publisher: IEEE
» Boundary Stabilization of Wave Equation With Velocity Recirculation
 Abstract:Nonlocal terms have been the mainstay of the applications of partial differential equation (PDE) backstepping methods to parabolic PDEs. The problem of similar nonlocal terms for wave equations is still open. For wave equations, similar nonlocal terms have not been studied. In this paper, we open the topic of exploration of control of wave PDEs with nonlocal terms. This paper is concerned with the wave equation with in-domain feedback/recirculation of a boundary velocity with a spatially constant coefficient. Due to this nonlocal term, the passivity of the wave equation is destroyed. We first design an explicit state feedback controller to achieve exponential stability for the closed-loop system. Then, we design the output feedback by using infinite-dimensional observer. The backstepping approach is adopted in investigation. It is shown that by using two measurements only, the output feedback makes the closed-loop system exponentially stable. Autors: Lingling Su;Wei Guo;Jun-Min Wang;Miroslav Krstic; Appeared in: IEEE Transactions on Automatic Control Publication date: Sep 2017, volume: 62, issue:9, pages: 4760 - 4767 Publisher: IEEE
» Bounded Selective Spanning With Extended Fast Enumeration for MIMO-OFDM Systems Detection
 Abstract:Sphere decoders allow receivers in multiple-input multiple-output (MIMO) communications systems to detect QAM symbols with quasi-optimal accuracy and low complexity compared with the ideal maximum likelihood detector. However, their high complexity relative to simple linear detectors means that the latter are still usually adopted, despite their lower detection performance. Configurable sphere decoders, such as selective spanning fast enumeration (SSFE), allow complexity to be reduced at the cost of lower performance and are hence ideal for transceivers for Internet-of-Things equipment, where scale, operating context and resource, and energy budgets vary dramatically. However, SSFE still suffers performance limitations due to the internal heuristics employed for symbol selection and enumeration and real time, and software-defined realizations for even moderately demanding MIMO standards, such as 802.11n, have not been recorded. This paper presents a new variant of SSFE which, by employing novel fast symbol enumeration and modulation dictionary spanning heuristics, increases performance and computational efficiency to the point where very substantial reductions in resource can be achieved without impacting detection accuracy relative to SSFE. This is demonstrated via a series of field programmable gate array-based detectors and , 16-QAM 802.11n MIMO. Autors: Yun Wu;John McAllister; Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers Publication date: Sep 2017, volume: 64, issue:9, pages: 2556 - 2568 Publisher: IEEE
» Braided Convolutional Codes With Sliding Window Decoding
 Abstract:In this paper, we present a novel sliding window decoding scheme based on iterative Bahl–Cocke–Jelinek–Raviv decoding for braided convolutional codes, a class of turbo-like codes with short constraint length component convolutional codes. The tradeoff between performance and decoding latency is examined and, to reduce decoding complexity, both uniform and nonuniform message passing schedules within the decoding window, along with early stopping rules, are proposed. We also perform a density evolution analysis of sliding window decoding to guide the selection of the window size and message passing schedule. Periodic puncturing is employed to obtain rate-compatible code rates of 1/2 and 2/3 starting from a rate 1/3 mother code and a code rate of 3/4 starting from a rate 1/2 mother code. Simulation results show that, with nonuniform message passing and periodic puncturing, near capacity performance can be maintained throughout a wide range of rates with reasonable decoding complexity and no visible error floors. Autors: Min Zhu;David G. M. Mitchell;Michael Lentmaier;Daniel J. Costello;Baoming Bai; Appeared in: IEEE Transactions on Communications Publication date: Sep 2017, volume: 65, issue:9, pages: 3645 - 3658 Publisher: IEEE
» Brain racers
 Abstract:IN OCTOBER 2016, inside a sold-out arena in Zurich, a man named Numa Poujouly steered his wheelchair up to the central podium. As the Swiss national anthem played, organizers of the world's first cyborg Olympics hung a gold medal around Poujouly's neck. The 30-yearold, who became paralyzed after a bicycle accident in his teens, had triumphed in the tournament's most futuristic event: a video-game-like race in which the competitors controlled their speeding avatars with just their minds. Autors: Serafeim Perdikis;Luca Tonin;Jose del R. Millan; Appeared in: IEEE Spectrum Publication date: Sep 2017, volume: 54, issue:9, pages: 44 - 51 Publisher: IEEE
» Breakdown Characteristics and Mechanisms of Short Needle–Plate Air Gap in High-Speed Airflow
 Abstract:To understand the flashover of roof insulators in high-speed airflows, the breakdown characteristics and mechanisms of a short needle–plate air gap are investigated. An interesting and important phenomenon is found based on an artificial wind tunnel: the breakdown voltage first increases and then decreases. An experiential formula is established to describe the relationship among the airflow velocity, gap distance, and breakdown voltage. A good consistency with the experimental results is obtained. Furthermore, the breakdown mechanisms of the air gap in high-speed airflows are proposed, and the phenomenon is explained and verified according to the theories of gas discharge and fluid dynamics. The airflow blowing effect, which includes the deflection effect and blown away effect, and the airflow density effect are proposed as two dominant factors that affect the breakdown process of the air gap in high-speed airflows. The variation trend of the breakdown voltage with the airflow velocity is predicted. Two extreme points are expected during the variation process; i.e., the breakdown voltage has a maximum and a minimum, to which more attention should be paid. This paper is helpful for the safety operation of roof insulators on the high-speed train. Autors: Yongqiang Kang;Xueqin Zhang;Chaoqun Shi;Yue Zhou;Yijie Liu;Guoqiang Gao;Wenfu Wei;Guangning Wu; Appeared in: IEEE Transactions on Plasma Science Publication date: Sep 2017, volume: 45, issue:9, pages: 2406 - 2415 Publisher: IEEE
» Broadband Giant Group Velocity Dispersion in Asymmetric InP Dual Layer, Dual Width Waveguides
 Abstract:Highly dispersive components enable photonic-integrated circuits for ultrafast optical pulse processing. This paper presents the design of an InP device with resonant giant group velocity dispersion. The waveguides have a dual layer, dual width geometry that enables tailoring of the group velocity resonance wavelength. By cascading sections with different resonance wavelengths we show how constant group velocity dispersion can be achieved over a 50-nm wavelength range. Depending on which one of two super modes is excited in this device, the dispersion can be either normal or anomalous with values of -23200 ps/(nm · km) or 8200 ps/(nm · km), respectively. Mode converters with> 90% efficiency are designed to facilitate selective excitation of one or the other mode. The complete device is expected to be compatible with existing active/passive photonic integration technology in the InP/InGaAsP material system that should allow the creation of monolithic ultrafast optical pulse processing systems. Autors: Jon Øyvind Kjellman;Ripalta Stabile;Kevin A. Williams; Appeared in: Journal of Lightwave Technology Publication date: Sep 2017, volume: 35, issue:17, pages: 3791 - 3800 Publisher: IEEE
» Broadband High-Gain Beam-Scanning Antenna Array for Millimeter-Wave Applications
 Abstract:A novel method of achieving low profile, broadband microstrip array antennas with high antenna gain is proposed for millimeter-wave applications. The element employs a novel third-order vertically coupled resonant structure that a U-slot resonator in the ground is used to couple with the feeding resonator and the radiating patch, simultaneously. This proposed structure can significantly improve the bandwidth and frequency selectivity without increasing the thickness of the antenna. Then, to achieve the subarray, a new wideband power divider with loaded resonators is employed, which can be used to further improve the bandwidth. To demonstrate the working schemes of broadside radiation and scanned beam, two array antennas are implemented on the same board. Measured results agree well with the simulations, showing a wide bandwidth from 22 to 32 GHz (FBW = 37%) with the gain of around 19 dBi. The beam-scanning array can realize a scanning angle of 25° over a broadband. In addition, due to the filtering features are integrated in the design, the proposed antenna could also reduce the complexity and potential cost of the frontends. Autors: Chun-Xu Mao;Steven Gao;Yi Wang; Appeared in: IEEE Transactions on Antennas and Propagation Publication date: Sep 2017, volume: 65, issue:9, pages: 4864 - 4868 Publisher: IEEE
» Broadband Multibeam Antenna Arrays Fed by Frequency-Dependent Butler Matrices
 Abstract:A novel concept of multibeam antenna arrays operating in an octave frequency band has been presented. To achieve multiple beams in such a wide bandwidth N-element antenna arrays are fed by frequency-dependent Butler matrices which smoothly change their properties across the bandwidth. The proposed Butler matrices are designed in such a way that for the selected inputs their amplitude and differential phase characteristics feature the ones obtained for Butler matrices at , whereas at they feature the properties of Butler matrices. The proposed concept has been verified by measurements of a multibeam antenna array operating in 1.75–3.5 GHz frequency range and extended showing the possibility of designing antenna arrays with higher number of beams. Autors: Krzysztof Wincza;Kamil Staszek;Slawomir Gruszczynski; Appeared in: IEEE Transactions on Antennas and Propagation Publication date: Sep 2017, volume: 65, issue:9, pages: 4539 - 4547 Publisher: IEEE
» Building the Foundation for "Generation Robot": Signal Processing is Helping to Make Robots a Part of Everyday Life [Special Reports]
 Abstract: Autors: John Edwards; Appeared in: IEEE Signal Processing Magazine Publication date: Sep 2017, volume: 34, issue:5, pages: 8 - 11 Publisher: IEEE
» Bulk-Silicon-Based Waveguides and Bends Fabricated Using Silicon Wet Etching: Properties and Limits
 Abstract:We develop a process of fabricating silicon waveguides and devices using a bulk silicon substrate. The fabrication process mainly consists of one silicon dry etching and one silicon wet etching. The use of silicon wet etching makes the process simple and inexpensive. Because of the anisotropic nature of silicon wet etching, the bulk-silicon-based (BSB) waveguide made by the process consists of an inverted-trapezoidal core on a rectangular pedestal and a trapezoidal base beneath the pedestal. In addition, geometrically smooth BSB waveguide bends can be achieved when the radii of curvature of the bends are sufficiently large. The propagation loss of the BSB waveguide depends on wet etching conditions and it is 4.0 or 0.79 dB/cm for transverse-magnetic polarization. It is confirmed that the minimum radius of curvature of the BSB waveguide bend is 500 μm. The BSB waveguides and bends are expected to be used to implement low-cost sensors with simple geometry. Autors: Bonwoo Ku;Kyoung-Soo Kim;Yonghan Kim;Min-Suk Kwon; Appeared in: Journal of Lightwave Technology Publication date: Sep 2017, volume: 35, issue:18, pages: 3918 - 3923 Publisher: IEEE
» Bundled Kernels for Nonuniform Blind Video Deblurring
 Abstract:We present a novel blind video deblurring approach by estimating a bundle of kernels and applying the residual deconvolution. Our approach adopts multiple kernels to represent spatially varying motion blur, and thus can cope with nonuniform video deblurring. For each blurred frame, we build a warping-based, space-variant motion blur model based on a bundle of homographies in between its adjacent frames. Then, the nearest sharp frame is employed to form an unblurred-blurred pair for solving the motion model and obtain a bundle of kernels at the blurred frame. Finally, we apply the deconvolution on the residual between the warped unblurred frame and blurred frame with the kernels. The blur kernel estimation and residual deconvolution are iteratively performed toward the deblurred frame, as well as significantly reducing artifacts such as ringings. Experiments show that our approach can efficiently remove the nonuniform video blurring, and achieves better deblurring results than some state-of-the-art methods. Autors: Lei Zhang;Le Zhou;Hua Huang; Appeared in: IEEE Transactions on Circuits and Systems for Video Technology Publication date: Sep 2017, volume: 27, issue:9, pages: 1882 - 1894 Publisher: IEEE
» Cache-Enabled Heterogeneous Cellular Networks: Optimal Tier-Level Content Placement
 Abstract:Caching popular contents at base stations (BSs) of a heterogeneous cellular network (HCN) avoids frequent information passage from content providers to the network edge, thereby reducing latency and alleviating traffic congestion in backhaul links. The potential of caching at the network edge for tackling 5G challenges has motivated recent studies on optimal content placement in large-scale HCNs. However, due to the complexity of the network performance analysis, the existing strategies were mostly based on approximation, heuristics, and intuition. In general, optimal strategies for content placement in HCNs remain largely unknown and deriving them forms the theme of this paper. To this end, we adopt the popular random HCN model, where tiers of BSs are modeled as independent Poisson point processes distributed in the plane with different densities. Furthermore, the random caching scheme is considered, where each of a given set of files with corresponding popularity measures is placed at each BS of a particular tier with a corresponding probability, called placement probability. The probabilities are identical for all BSs in the same tier but vary over tiers, giving the name tier-level content placement. We consider the network performance metric, hit probability, defined as the probability that a file requested by the typical user is delivered successfully to the user. Leveraging existing results on HCN performance, we maximize the hit probability over content placement probabilities, which yields the optimal tier-level placement policies. For the case of uniform received signal-to-interference (SIR) thresholds for successful transmissions for BSs in different tiers, the policy is in closed-form, - here the placement probability for a particular file is proportional to the square-root of the corresponding popularity measure with an offset depending on BS caching capacities. For the general case of non-uniform SIR thresholds, the optimization problem is non-convex and a sub-optimal placement policy is designed by approximation, which has a similar structure as in the case of uniform SIR thresholds and shown by simulation to be close-to-optimal. Autors: Juan Wen;Kaibin Huang;Sheng Yang;Victor O. K. Li; Appeared in: IEEE Transactions on Wireless Communications Publication date: Sep 2017, volume: 16, issue:9, pages: 5939 - 5952 Publisher: IEEE
» Calendar [Calendar]
 Abstract: Autors: Amy Reeder; Appeared in: IEEE Robotics & Automation Magazine Publication date: Sep 2017, volume: 24, issue:3, pages: 183 - 183 Publisher: IEEE
» Calibration of Bulk Trap-Assisted Tunneling and Shockley–Read–Hall Currents and Impact on InGaAs Tunnel-FETs
 Abstract:The tunnel-FET (TFET) is a promising candidate for future low-power logic applications, because it enables a sub-60-mV/decadesubthresholdswing. However, themost experimental TFETs are plagued by unwanted trap-assisted tunneling (TAT) and Shockley–Read–Hall (SRH) carrier generation, which degrade the swing and increase the leakage floor, hence forming a major roadblock for TFET adoption. This degradation is attributed to bulk traps, semiconductor/oxideinterface traps, and/or heterojunction interface traps, but it is still unclear which of the three trap types are dominant. In this paper, we focus on TAT and SRH caused by bulk traps. We calibrate SRH and TAT models with the help of In0.53Ga0.47As p+/n+ and p+/i/n+ diodes grown on lattice matched substrates by molecular beam epitaxy (MBE). We then perform calibrated simulations of an In0.53Ga0.47As TFET, which show bulk SRH and TAT are sufficiently low compared with the target OFF-state current and, hence, not a significant issue. Therefore, it is likely that high SRH and TAT commonly observed in experimental homojunction InGaAs TFETs, MBE-grown on lattice matched substrates, are not caused by bulk semiconductor defects, but by semiconductor/oxide interface defects. Autors: Quentin Smets;Anne S. Verhulst;Eddy Simoen;David Gundlach;Curt Richter;Nadine Collaert;Marc M. Heyns; Appeared in: IEEE Transactions on Electron Devices Publication date: Sep 2017, volume: 64, issue:9, pages: 3622 - 3626 Publisher: IEEE
» Calibration of Floating-Gate SoC FPAA System
 Abstract:We present a calibration flow for a large-scale floating-gate (FG) system-on-chip field programmable analog array. We focus on characterizing the FG programming infrastructure and hot-electron injection parameters, MOSFET parameters using the EKV model, and calibrating digital-analog converters and analog-digital converters. In addition, threshold voltage mismatches on FG devices due to their indirect structure are characterized using on-chip measurement techniques. The calibration results in enabling a digital approach, where a design can be programmed without having to deal with the local and global mismatches, on a reconfigurable analog system. This paper shows the results of a compiled nonlinear classifier block comprising a vector-matrix-multiplier and a winner-takes-all on three different calibrated chips. Autors: Sihwan Kim;Sahil Shah;Jennifer Hasler; Appeared in: IEEE Transactions on Very Large Scale Integration Systems Publication date: Sep 2017, volume: 25, issue:9, pages: 2649 - 2657 Publisher: IEEE
» Cameras, Music, and Synergy in Signal Processing [From the Editor]
 Abstract: Autors: Min Wu; Appeared in: IEEE Signal Processing Magazine Publication date: Sep 2017, volume: 34, issue:5, pages: 3 - 4 Publisher: IEEE
» Capacitated Next Controller Placement in Software Defined Networks
 Abstract:Software defined networking shifts the control plane of forwarding devices to one or more external entities known as controllers. Determining the optimal location of controllers in the network and the assignment of switches to them is widely known as controller placement problem. In case of controller failures, the switches are disconnected from the controller until they are reassigned to other active controllers with enough spare capacity. However, there is a significant upsurge in the worst case latency after the reassignment due to lack of planning for controller failures. In this paper, we propose a controller placement strategy that not only considers reliability and capacity of controllers but also plans ahead for controller failures to avoid repeated administrative intervention, drastic increase in latency and disconnections. It is formulated as a mixed integer linear program. The objective is to minimize the maximum, for all switches, of the sum of the latency from the switch to the nearest controller with enough capacity (first reference controller) and the latency from the first reference controller to its closest controller with enough capacity (second reference controller). We also proposed a generalized model which can be used to minimize the average latency and extended it for multiple controller failures. Furthermore, we presented a simulated annealing heuristic that efficiently solves the problem on large scale networks. The proposed formulation and heuristic are evaluated on various networks from the Internet Topology Zoo. Simulation results show that our proposed method performs better than the controller placement that does not plan ahead for failures. Autors: Bala Prakasa Rao Killi;Seela Veerabhadreswara Rao; Appeared in: IEEE Transactions on Network and Service Management Publication date: Sep 2017, volume: 14, issue:3, pages: 514 - 527 Publisher: IEEE
» Capacitor-Loaded Spoof Surface Plasmon for Flexible Dispersion Control and High-Selectivity Filtering
 Abstract:This letter proposes a new spoof surface plasmon transmission line (SSP-TL) using capacitor loading technique. This new SSP-TL features flexible and reconfigurable dispersion control and highly selective filtering performance without resorting to configuration change. Moreover, it requires much smaller linewidth than the conventional SSP-TL for achieving an extremely slow wave (or a highly confined field), which is quite useful for a compact system. To illustrate the design principle, several examples are designed within the frequency range of 2–8 GHz. Both numerical and experimental results are given in comparison with the conventional SSP-TL. It is demonstrated that the proposed technique provides a better performance in size reduction and dispersion reconfigurability. Autors: Xiao-Lan Tang;Qingfeng Zhang;Sanming Hu;Abhishek Kandwal;Tongfeng Guo;Yifan Chen; Appeared in: IEEE Microwave and Wireless Components Letters Publication date: Sep 2017, volume: 27, issue:9, pages: 806 - 808 Publisher: IEEE
» Capacity Analysis of Discrete Energy Harvesting Channels
 Abstract:We study the channel capacity of a general discrete energy harvesting channel with a finite battery. Contrary to traditional communication systems, the transmitter of such a channel is powered by a device that harvests energy from a random exogenous energy source and has a finite-sized battery. As a consequence, at each transmission opportunity, the system can only transmit a symbol whose energy is no more than the energy currently available. This new type of power supply introduces an unprecedented input constraint for the channel, which is simultaneously random, instantaneous, and influenced by the full history of the inputs and the energy harvesting process. Furthermore, naturally, in such a channel, the energy information is observed causally at the transmitter. Both of these characteristics pose great challenges for the analysis of the channel capacity. In this paper, we use techniques developed for channels with side information and finite-state channels, to obtain lower and upper bounds on the capacity of energy harvesting channels. In particular, in a general case with Markov energy harvesting processes, we use stationarity and ergodicity theory to compute and optimize the achievable rates for the channels, and derive a series of computable capacity upper and lower bounds. Autors: Wei Mao;Babak Hassibi; Appeared in: IEEE Transactions on Information Theory Publication date: Sep 2017, volume: 63, issue:9, pages: 5850 - 5885 Publisher: IEEE
» Capacity Configuration and Coordinated Operation of a Hybrid Wind Farm With FSIG-Based and PMSG-Based Wind Farms During Grid Faults
 Abstract:This paper mainly proposes a capacity configuration strategy for a hybrid wind farm with fixed-speed induction generator (FSIG)-based and permanent magnet synchronous generator (PMSG)-based wind farms during grid faults. In this paper, FSIG-based wind farm realizes low voltage ride through (LVRT) with the associated control of nearby PMSG systems as StatComs to provide the required reactive power. By establishing the mathematical model of hybrid wind farm containing network parameters, the operation characteristics of the FSIG-based wind farm during grid faults are analyzed in detail. Based on the characteristics and the critical clearing time of FSIG-based wind farm, a novel capacity configuration method for the hybrid wind farm is proposed to calculate the required reactive power of FSIG-based wind farm for a LVRT operation. Based on the capacity configuration result, the minimum installed capacity of PMSG-based wind farm could be determined. Taking into account the impact of reactive power compensation capacity and grid transmission line parameters, the coordinated LVRT capability of the hybrid wind farm is then analyzed. Finally, simulation and experimental results demonstrate the effectiveness of the proposed capacity configuration method and the coordinated operation performance of the hybrid wind farm respectively. Autors: Jun Yao;Lisha Guo;Te Zhou;Depeng Xu;Ruikuo Liu; Appeared in: IEEE Transactions on Energy Conversion Publication date: Sep 2017, volume: 32, issue:3, pages: 1188 - 1199 Publisher: IEEE

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