#### Electrical and Electronics Engineering publications abstract of: 09-2017 sorted by title, page: 5

» Comparative Study of RESURF Si/SiC LDMOSFETs for High-Temperature Applications Using TCAD Modeling
 Abstract:This paper analyses the effect of employing an Si on semi-insulating SiC (Si/SiC) device architecture for the implementation of 600-V LDMOSFETs using junction isolation and dielectric isolation reduced surface electric field technologies for high-temperature operations up to 300 °C. Simulations are carried out for two Si/SiC transistors designed with either PN or silicon-on-insulator (SOI) and their equivalent structures employing bulk-Si or SOI substrates. Through comparisons, it is shown that the Si/SiC devices have the potential to operate with an off-state leakage current as low as the SOI device. However, the low-side resistance of the SOI LDMOSFET is smaller in value and less sensitive to temperature, outperforming both Si/SiC devices. Conversely, under high-side configurations, the Si/SiC transistors have resistances lower than that of the SOI at high substrate bias, and invariablewith substrate potential up to −200 V, which behaves similar to the bulk-Si LDMOS at 300 K. Furthermore, the thermal advantage of the Si/SiC over other structures is demonstrated by using a rectanglepower pulse setup in TechnologyComputer-Aided Design simulations. Autors: C. W. Chan;F. Li;A. Sanchez;P. A. Mawby;P. M. Gammon; Appeared in: IEEE Transactions on Electron Devices Publication date: Sep 2017, volume: 64, issue:9, pages: 3713 - 3718 Publisher: IEEE
» Comparison for 1/ ${f}$ Noise Characteristics of AlGaN/GaN FinFET and Planar MISHFET
 Abstract:DC and 1/ noise performances of the AlGaN/GaN fin-shaped field-effect transistor (FinFET) with fin width of 50 nm were analyzed. The FinFET exhibited approximately six times larger normalized drain current and transconductance, compared to those of the AlGaN/GaN planar metal-insulator-semiconductor heterostructure field-effect-transistor (MISHFET) fabricated on the same wafer. It was also observed that the FinFET exhibited improved noise performance with lower noise magnitude of /Hz when compared to the value of /Hz for the planar MISHFET. An intensive analysis indicated that both devices follow the carrier number fluctuation model, but the FinFET suffers much less charge trapping effect compared to the MISHFET (two orders lower charge trapping was observed). Moreover, the FinFET did not exhibit the Lorentz-like components, which explains that the depleted fin structure effectively prevents the carriers from being trapped into the underlying thick GaN buffer layer. On the other hand, the slope of the noise is 2 irrespective of drain voltage and apparently showed the Lorentz-like components, especially at high drain voltage in MISHFET device. This explains that the carrier trapping/detrapping between the 2-D electron gas channel and the GaN buffer layer is significant in MISHFET. Autors: Sindhuri Vodapally;Christoforos G. Theodorou;Youngho Bae;Gérard Ghibaudo;Sorin Cristoloveanu;Ki-Sik Im;Jung-Hee Lee; Appeared in: IEEE Transactions on Electron Devices Publication date: Sep 2017, volume: 64, issue:9, pages: 3634 - 3638 Publisher: IEEE
» Comparison of Collision-Free and Contention-Based Radio Access Protocols for the Internet of Things
 Abstract:The fifth-generation (5G) cellular networks will face the challenge of integrating the traditional broadband services with the Internet of Things (IoT), which is characterized by sporadic uplink transmissions of small data packets. Indeed, the access procedure of the previous generation cellular network (4G) is not able to support IoT traffic efficiently, because it requires a large amount of signaling for the connection setup before the actual data transmission. In this context, we introduce two innovative radio access protocols for sporadic transmissions of small data packets, which are suitable for 5G networks, because they provide a resource-efficient packet delivery exploiting a connectionless approach. The core of this paper resides in the derivation of an analytical framework to evaluate the performance of all the aforementioned protocols. The final goal is the comparison between 4G and 5G radio access solutions employing both our analytical framework and computer simulations. The performance evaluation results show the benefits of the protocols envisioned for 5G in terms of signaling overhead and access latency. Autors: Marco Centenaro;Lorenzo Vangelista;Stephan Saur;Andreas Weber;Volker Braun; Appeared in: IEEE Transactions on Communications Publication date: Sep 2017, volume: 65, issue:9, pages: 3832 - 3846 Publisher: IEEE
» Comparison of Constant-Posture Force-Varying EMG-Force Dynamic Models About the Elbow
 Abstract:Numerous techniques have been used to minimize error in relating the surface electromyogram (EMG) to elbow joint torque. We compare the use of three techniques to further reduce error. First, most EMG-torque models only use estimates of EMG standard deviation as inputs. We studied the additional features of average waveform length, slope sign change rate and zero crossing rate. Second, multiple channels of EMG from the biceps, and separately from the triceps, have been combined to produce two low-variance model inputs. We contrasted this channel combination with using each EMG separately. Third, we previously modeled nonlinearity in the EMG-torque relationship via a polynomial. We contrasted our model versus that of the classic exponential power law of Vredenbregt and Rau (1973). Results from 65 subjects performing constant-posture, force-varying contraction gave a “baseline” comparison error (i.e., error with none of the new techniques) of 5.5 ± 2.3% maximum flexion voluntary contraction (%MVCF). Combining the techniques of multiple features with individual channels reduced error to 4.8 ± 2.2 %MVCF, while combining individual channels with the power-law model reduced error to 4.7 ± 2.0 %MVCF. The new techniques further reduced error from that of the baseline by %. Autors: Chenyun Dai;Berj Bardizbanian;Edward A. Clancy; Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering Publication date: Sep 2017, volume: 25, issue:9, pages: 1529 - 1538 Publisher: IEEE
» Comparison on the Synchronization of Two Parallel GaAs Photoconductive Semiconductor Switches Excited by Laser Diodes
 Abstract:In this letter, the synchronization of GaAs photoconductive semiconductor switches in two electrically driven configurations for laser diodes excitation is investigated. Comparisons on the synchronization are carried out by varying the bias electric field and optical excitation energy. The optimum synchronization of 296 ps is achieved at 1.2 kV with optical excitation energy of . The results demonstrate the relationship between the synchronization and transient carriers’ population ratio among the intervalley. Autors: Wei Shi;Yu Ji;Ming Xu;Cui Chen;Junjun Shi;Shaoqiang Wang;Rujun Liu; Appeared in: IEEE Electron Device Letters Publication date: Sep 2017, volume: 38, issue:9, pages: 1274 - 1277 Publisher: IEEE
» Comparison Study of Noncontact Vital Signs Detection Using a Doppler Stepped-Frequency Continuous-Wave Radar and Camera-Based Imaging Photoplethysmography
 Abstract:In this paper, we compare the performance of radar and optical (camera based) techniques in detecting vital signs such as respiratory rate (RR), heart rate (HR), and blood oxygen saturation (SpO2). Specifically, we investigate the application of ultrawideband stepped-frequency continuous-wave radar and imaging photoplethysmography (iPPG) techniques to measure vital signs. The radar performance can be enhanced by using phase information of backscattered signal instead of its amplitude. On the other hand, the iPPG system can be enhanced by using more than one camera and utilizing very selective narrowband filters coupled with good illumination. In either system, use of advanced signal processing is required to improve accuracy. Generally, HR and RR can be accurately read by either microwave radar or optical techniques with 500 lx illumination level to have < ±2% error up to 2 m distance between the subject and the system, but optical technique errors increase significantly to < ±15% for <200 lx. However, each system has its unique advantages as the radar can be used for seeing-through walls and optical technique is uniquely capable of measuring SpO2). Autors: Lingyun Ren;Lingqin Kong;Farnaz Foroughian;Haofei Wang;Paul Theilmann;Aly E. Fathy; Appeared in: IEEE Transactions on Microwave Theory and Techniques Publication date: Sep 2017, volume: 65, issue:9, pages: 3519 - 3529 Publisher: IEEE
» Compensation of Long-Term Memory Effects on GaN HEMT-Based Power Amplifiers
 Abstract:The long-term memory effects of gallium nitride (GaN) transistors have prevented its use in situations where the modulated envelope signal has a wide amplitude variation over time, such as in time division duplex systems. These long-term memory effects are generally attributed to electron trapping in GaN high electron-mobility transistors (HEMT), which have shown to be very difficult to compensate, especially in cellular base station transmitters known to be subjected to highly restrictive linearity specifications. On top of the electron trapping effects, we show that thermal effects can also induce long-term memory behaviors, which should also be accounted for when linearizing these devices. Because the conventional behavioral modeling approach has been incapable to compensate these long-term memory effects on GaN HEMT-based power amplifiers (PAs), we started by investigating the physical mechanisms responsible for these semiconductor impairments in GaN devices. This physics-based knowledge was then used to design new predistorter models that could effectively compensate those PAs subjected to GaN trapping and thermal effects. In this paper, we describe the new predistortion models for PA linearization, as well as the characterization methods used to determine their parameters. To validate the linearization effectiveness of the proposed model, several high power GaN-based PAs are tested with multicarrier GSM signals, and their linearization results are compared against other state-of-the-art models, evidencing a clear and significant improvement. In fact, to the authors’ knowledge, the proposed approach is the first one to reduce the PA distortion effects due to GaN long-term memory effects to such low levels, allowing a comfortable compliance with the imposed linearity masks. Autors: Filipe M. Barradas;Luís C. Nunes;Telmo R. Cunha;Pedro M. Lavrador;Pedro M. Cabral;José C. Pedro; Appeared in: IEEE Transactions on Microwave Theory and Techniques Publication date: Sep 2017, volume: 65, issue:9, pages: 3379 - 3388 Publisher: IEEE
» Complex Delta–Sigma-Based Transmitter With Enhanced Linearity Performance Using Pulsed Load Modulation Power Amplifier
 Abstract:This paper proposes a linear and efficient transmitter prototype based on pulsed load modulation (PLM) power amplifier (PA). The proposed transmitter setup utilizes the complex delta–sigma (DS) modulation as a signal processing technique instead of the envelope DS modulation for higher linearity performance. Using the complex DS modulation technique reduces the in-band quantization noise significantly at the output of the modulator and consequently, enhances the linearity of the transmitter. To validate the proposed technique, the linearity and efficiency performance of the complex DS modulator (CDSM)-based transmitter are compared with the performance of its envelope DS modulator (EDSM) counterpart in measurement. For this paper, an efficient and linear PLM PA is designed and fabricated using GaAs E-pHEMT transistors. For a Long-Term Evolution (LTE) uplink standard signal with 3-MHz bandwidth and 7-dB peak-to-average power ratio, the CDSM-based transmitter achieves the drain efficiency and power added efficiency of 46% and 42%, respectively, at an average output power of 25.1 dBm. The comparison measurement study of EDSM-based transmitter and the CDSM-based transmitter with the LTE uplink signal shows about 11-dB improvement in the signal-to-noise and distortion ratio of the output signal. The measurement results for LTE signals were able to pass the spectral requirements defined by the standard without applying predistortion techniques. Autors: Maryam Jouzdani;Mohammad Mojtaba Ebrahimi;Mohamed Helaoui;Fadhel M. Ghannouchi; Appeared in: IEEE Transactions on Microwave Theory and Techniques Publication date: Sep 2017, volume: 65, issue:9, pages: 3324 - 3335 Publisher: IEEE
» Composability Verification of Multi-Service Workflows in a Policy-Driven Cloud Computing Environment
 Abstract:The emergence of cloud computing infrastructure and Semantic Web technologies has created unprecedented opportunities for composing large-scale business processes and workflow-based applications that span multiple organizational domains. A key challenge related to composition of such multi-organizational business processes and workflows is posed by the security and access control policies of the underlying organizational domains. In this paper, we propose a framework for verifying secure composability of distributed workflows in an autonomous multi-domain environment. The objective of workflow composability verification is to ensure that all the users or processes executing the designated workflow tasks conform to the time-dependent security policy specifications of all collaborating domains. A key aspect of such verification is to determine the time-dependent schedulability of distributed workflows, assumed to be invoked on a recurrent basis. We use a two-step approach for verifying secure workflow composability. In the first step, a distributed workflow is decomposed into domain-specific projected workflows and is verified for conformance with the respective domain's security and access control policy. In the second step, the cross-domain dependencies amongst the workflow tasks performed by different collaborating domains are verified. Autors: Basit Shafiq;Sameera Ghayyur;Ammar Masood;Zahid Pervaiz;Abdulrahman Almutairi;Farrukh Khan;Arif Ghafoor; Appeared in: IEEE Transactions on Dependable and Secure Computing Publication date: Sep 2017, volume: 14, issue:5, pages: 478 - 493 Publisher: IEEE
» Comprehensive Capacitance–Voltage Simulation and Extraction Tool Including Quantum Effects for High- $k$ on SixGe1−x and InxGa1−xAs: Part II—Fits and Extraction From Experimental Data
 Abstract:Capacitance-voltage (–) measurement and analysis is highly useful for determining important information about MOS gate stacks. Parameters such as the equivalent oxide thickness (EOT), substrate doping density, flatband voltage, fixed oxide charge, density of interface traps (), and effective gate work function can all be extracted from experimental – curves. However, to extract these gate-stack parameters accurately, the correct models must be utilized. In Part I, we described the modeling and implementation of a – code that can be used for alternative channel semiconductors in conjunction with high- gate dielectrics and metal gates. Importantly, this new code (CV ACE) includes the effects of nonparabolic bands and quantum capacitance, enabling accurate models to be applied to experimental – curves. In this paper, we demonstrate the capabilities of this new code to extract accurate parameters, including EOT and profiles from experimental high- on Ge and In0.53<- sub>Ga0.47As gate stacks. Autors: Sarkar R. M. Anwar;William G. Vandenberghe;Gennadi Bersuker;Dmitry Veksler;Giovanni Verzellesi;Luca Morassi;Rohit V. Galatage;Sumit Jha;Creighton Buie;Adam T. Barton;Eric M. Vogel;Christopher L. Hinkle; Appeared in: IEEE Transactions on Electron Devices Publication date: Sep 2017, volume: 64, issue:9, pages: 3794 - 3801 Publisher: IEEE
» Comprehensive Capacitance–Voltage Simulation and Extraction Tool Including Quantum Effects for High-k on SixGe1−x and InxGa1−xAs: Part I—Model Description and Validation
 Abstract:High-mobility alternative channel materials to silicon are critical to the continued scaling of MOS devices. The analysis of capacitance–voltage (C–V) measurements on these new materials with high-k gate dielectrics is a critical technique to determine many important gate-stack parameters. While there are very useful C–V analysis tools available to the community, these tools are all limited in their applicability to alternative semiconductor channel MOS gate-stack analysis since they were developed for silicon. Here, we report on a new comprehensive C–V simulation and extraction tool, called CV Alternative Channel Extraction (ACE), that incorporates a wide range of semiconductors and dielectrics with the capability to implement customized gate stacks. Fermi–Dirac carrier statistics, nonparabolic bands, and quantum mechanical effects are all implemented with options to turn each of these off as the user desires. Interface state capacitance () is implemented using a common model for systems like Si and Ge. A more complex model is also implemented for III–Vs that accurately captures frequency dispersion in accumulation that arises from tunneling. CV ACE enables extremely fast simulation and extraction and can accommodate measurements performed at variable temperatures and frequencies to allow for a more accurate extraction of interface state density (). Autors: Sarkar R. M. Anwar;William G. Vandenberghe;Gennadi Bersuker;Dmitry Veksler;Giovanni Verzellesi;Luca Morassi;Rohit V. Galatage;Sumit Jha;Creighton Buie;Adam T. Barton;Eric M. Vogel;Christopher L. Hinkle; Appeared in: IEEE Transactions on Electron Devices Publication date: Sep 2017, volume: 64, issue:9, pages: 3786 - 3793 Publisher: IEEE
» Compressed Level Crossing Sampling for Ultra-Low Power IoT Devices
 Abstract:Level crossing sampling (LCS) is a power-efficient analog-to-digital conversion scheme for spikelike signals that arise in many Internet of Things-enabled automotive and environmental monitoring applications. However, LCS scheme requires a dedicated time-to-digital converter with large dynamic range specifications. In this paper, we present a compressed LCS that exploits the signal sparsity in the time domain. At the compressed sampling stage, a continuous-time ternary encoding scheme converts the amplitude variations into a ternary timing signal that is captured in a digital random sampler. At the reconstruction stage, a low-complexity split-projection least squares (SPLSs) signal reconstruction algorithm is presented. The SPLS splits random projections and utilizes a standard least squares approach that exploits the ternary-valued amplitude distribution. The SPLS algorithm is hardware friendly, can be run in parallel, and incorporates a low-cost k-term approximation scheme for matrix inversion. The SPLS hardware is analyzed, designed, and implemented in FPGA, achieving the highest data throughput and the power efficiency compared with the prior arts. Simulations of the proposed sampler in an automotive collision warning system demonstrate that the proposed compressed LCS can be very power efficient and robust to wireless interference, while achieving an approximately eightfold data volume compression when compared with Nyquist sampling approaches. Autors: Jun Zhou;Amir Tofighi Zavareh;Robin Gupta;Liang Liu;Zhongfeng Wang;Brian M. Sadler;Jose Silva-Martinez;Sebastian Hoyos; Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers Publication date: Sep 2017, volume: 64, issue:9, pages: 2495 - 2507 Publisher: IEEE
» Compressed Training Adaptive Equalization: Algorithms and Analysis
 Abstract:We propose “compressed training adaptive equalization” as a novel framework to reduce the quantity of training symbols in a communication packet. It is a semi-blind approach for communication systems employing time-domain/frequency-domain equalizers, and founded upon the idea of exploiting the magnitude boundedness of digital communication symbols. The corresponding algorithms are derived by combining the least-squares-cost-function measuring the training symbol reconstruction performance and the infinity-norm of the equalizer outputs as the cost for enforcing the special constellation boundedness property along the whole packet. In addition to providing a framework for developing effective adaptive equalization algorithms based on convex optimization, the proposed method establishes a direct link with compressed sensing by utilizing the duality of the and norms. This link enables the adaptation of recently emerged -norm-minimization-based algorithms and their analysis to the channel equalization problem. In particular, we show for noiseless/low noise scenarios, the required training length is on the order of the logarithm of the channel spread. Furthermore, we provide approximate performance analysis by invoking the recent MSE results from the sparsity-based data processing literature. Provided examples illustrate the significant training reductions by the proposed approach and demonstrate its potential for high bandwidth systems with fast mobility. Autors: Baki B. Yilmaz;Alper T. Erdogan; Appeared in: IEEE Transactions on Communications Publication date: Sep 2017, volume: 65, issue:9, pages: 3907 - 3921 Publisher: IEEE
» Condition Codes Evaluation on Dynamic Binary Translation for Embedded Platforms
 Abstract:A widely recognized issue when implementing dynamic binary translation is the condition codes (CCs) or flag bits emulation. The authors in the literature have approached this problem with software optimization techniques based on dataflow analysis, instruction set architecture (ISA) extensions and additional dedicated hardware, i.e., field-programmable gate array. We introduce a novel technique to handle CCs using commercial off-the-shelf architectural debug hardware as a triggering mechanism while assessing and comparing it with two existent CCs evaluation methods on the resource-constrained embedded systems arena. Our method is functionality-wise comparable with reconfigurable hardware modules or ISA extensions in open architectures and is source architecture independent, with possible applications in other use scenarios, such as application debugging and instrumentation. Autors: Filipe Salgado;Tiago Gomes;Sandro Pinto;Jorge Cabral;Adriano Tavares; Appeared in: IEEE Embedded Systems Letters Publication date: Sep 2017, volume: 9, issue:3, pages: 89 - 92 Publisher: IEEE
» Conflict-Free Loop Mapping for Coarse-Grained Reconfigurable Architecture with Multi-Bank Memory
 Abstract:Coarse-grained reconfigurable architecture (CGRA) is a promising architecture with high performance, high power-efficiency and attraction of flexibility. The computation-intensive parts of an application (e.g., loops) are often mapped on CGRA for acceleration. Due to the high parallel data access demands, the architecture with multi-bank memory is proposed to improve parallelism. For CGRA with multi-bank memory, a joint solution, which simultaneously considers the memory partitioning and modulo scheduling, is proposed to achieve a valid mapping with better performance. In this solution, the modulo scheduling and operator scheduling are used to achieve a valid loop mapping and a valid data placement without any memory access conflicts. By avoiding the pipelining stalls caused by conflicts, the performance of loop mapping is greatly improved. The experimental results on benchmarks of the Livermore, Polybench and Mediabench show that our approach can improve the performance of loops on CGRA to 1.89, 1.49 and 1.37 compared with REGIMap, HTDM and REGIMap with memory partitioning, at cost of an acceptable increase in compilation time. Autors: Shouyi Yin;Xianqing Yao;Tianyi Lu;Dajiang Liu;Jiangyuan Gu;Leibo Liu;Shaojun Wei; Appeared in: IEEE Transactions on Parallel and Distributed Systems Publication date: Sep 2017, volume: 28, issue:9, pages: 2471 - 2485 Publisher: IEEE
» Confusion-Matrix-Based Kernel Logistic Regression for Imbalanced Data Classification
 Abstract:There have been many attempts to classify imbalanced data, since this classification is critical in a wide variety of applications related to the detection of anomalies, failures, and risks. Many conventional methods, which can be categorized into sampling, cost-sensitive, or ensemble, include heuristic and task dependent processes. In order to achieve a better classification performance by formulation without heuristics and task dependence, we propose confusion-matrix-based kernel logistic regression (CM-KLOGR). Its objective function is the harmonic mean of various evaluation criteria derived from a confusion matrix, such criteria as sensitivity, positive predictive value, and others for negatives. This objective function and its optimization are consistently formulated on the framework of KLOGR, based on minimum classification error and generalized probabilistic descent (MCE/GPD) learning. Due to the merits of the harmonic mean, KLOGR, and MCE/GPD, CM-KLOGR improves the multifaceted performances in a well-balanced way. This paper presents the formulation of CM-KLOGR and its effectiveness through experiments that comparatively evaluated CM-KLOGR using benchmark imbalanced datasets. Autors: Miho Ohsaki;Peng Wang;Kenji Matsuda;Shigeru Katagiri;Hideyuki Watanabe;Anca Ralescu; Appeared in: IEEE Transactions on Knowledge and Data Engineering Publication date: Sep 2017, volume: 29, issue:9, pages: 1806 - 1819 Publisher: IEEE
» Conic Programming-Based Lagrangian Relaxation Method for DCOPF With Transmission Losses and its Zero-Gap Sufficient Condition
 Abstract:This paper presents a fast optimization approach framework for the DC optimal power flow (DCOPF) with the consideration of transmission losses, which is confronted with nonconvex quadratically constrained quadratic programming. Specifically, a second-order cone programming-based Lagrangian relaxation method is employed to obtain the lower bound of the original DCOPF. Furthermore, a sufficient condition for the zero-gap relaxation is derived, which is easy to be satisfied in practice. Finally, the comparison with existing DCOPF solvers shows that the proposed method could achieve the global optimal solution and jump out of the local optimality. Also, the comparison with the widely used semidefinite programming relaxation approach indicates that the proposed relaxation method needs less dummy variables, and thus can be more efficiently solved and more applicable for large-scale power systems. Autors: Tao Ding;Chaoyue Zhao;Tianen Chen;Ruifeng Liu; Appeared in: IEEE Transactions on Power Systems Publication date: Sep 2017, volume: 32, issue:5, pages: 3852 - 3861 Publisher: IEEE
» Connected Vehicular Transportation: Data Analytics and Traffic-Dependent Networking
 Abstract:With onboard operating systems becoming increasingly common in vehicles, the realtime broadband infotainment and intelligent transportation system (ITS) service applications in fast-moving vehicles become ever demanding, and they are expected to significantly improve the efficiency and safety of our daily on-road lives. The emerging ITS and vehicular applications (e.g., trip planning), however, require substantial efforts in real-time pervasive information collection and big data processing to allow quick decision making and feedback to fast-moving vehicles, which imposes significant challenges on the development of an efficient vehicular communication platform. In this article, we present TrasoNET, an integrated network framework that provides real-time intelligent transportation services to connected vehicles by exploring the data analytics and networking techniques. TrasoNET is built upon two key components. The first guides vehicles to the appropriate access networks by exploring the real-time status of local traffic, specific user preferences, service applications, and network conditions. The second mainly involves a distributed automatic access engine, which enables individual vehicles to make distributed access decisions based on recommendations, local observations, and historic information. We highlight the application of TrasoNET in a case study on real-time traffic sensing based on real traces of taxis. Autors: Cailian Chen;Tom Hao Luan;Xinping Guan;Ning Lu;Yunshu Liu; Appeared in: IEEE Vehicular Technology Magazine Publication date: Sep 2017, volume: 12, issue:3, pages: 42 - 54 Publisher: IEEE
» Connecting Things to the IoT by Using Virtual Peripherals on a Dynamically Multithreaded Cortex M3
 Abstract:The Internet of Things communicates with the world by using a wide range of different sensors and actuators. These interfaces are based on a wide range of various protocols, such as I2C, SPI, RS232, 1-wire, and so on. There are two conceptional different solutions to provide these interfaces. One is to use dedicated hardware for it. An example would be to use a peripheral on a system-on-a-chip (SoC). All SoC providers offer the families of SoC solutions with different kind of hardware peripheral combinations. The alternative concept it to run virtual peripherals as a software routine on a CPU, preferable on a multithreaded CPU. C-Slow Retiming (CSR) is a known design transformation to generate multithreaded CPUs. This paper argues, that system hyper pipelining overcomes the limitations of CSR by adding thread stalling, bypassing, and reordering techniques to better cope with the challenges of multithreading. This dynamic multithreaded environment is ideal for running virtual peripheral. The benefits of using system hyper pipelining for virtual peripherals are demonstrated on a Cortex M3-based system. Autors: Tobias Strauch; Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers Publication date: Sep 2017, volume: 64, issue:9, pages: 2462 - 2469 Publisher: IEEE
» Considering Backhaul [Book\Software Reviews]
 Abstract:This book offers a comprehensive guide to the subject of microwave backhaul. Design information on this subject is sparse, and it is not easy to collect and interpret. This fact was the driving force behind the creation of this book, which focuses on the electronics of backhaul and describes in detail all the subsystems responsible for transforming the information signal that comes from baseband processing into an electromagnetic wave traveling through the air. Electronics for Microwave Backhaul presents an overview of the evolution of the electronics for microwave radios, from their initial development to present implementations and future trends. The authors have stayed abreast of current real-world industry products and present many real-world solutions to the design issues. Autors: James Chu; Appeared in: IEEE Microwave Magazine Publication date: Sep 2017, volume: 18, issue:6, pages: 125 - 126 Publisher: IEEE
» Constant Compositions in the Sphere Packing Bound for Classical-Quantum Channels
 Abstract:The sphere packing bound, in the form given by Shannon, Gallager, and Berlekamp, was recently extended to classical-quantum channels, and it was shown that this creates a natural setting for combining probabilistic approaches with some combinatorial ones such as the Lovász theta function. In this paper, we extend the study to the case of constant-composition codes. We first extend the sphere packing bound for classical-quantum channels to this case, and we then show that the obtained result is related to a variation of the Lovász theta function studied by Marton. We then propose a further extension to the case of varying channels and codewords with a constant conditional composition given a particular sequence. This extension is finally applied to auxiliary channels to deduce a bound, which is useful in the low rate region and which can be interpreted as an extension of the Elias bound. Autors: Marco Dalai;Andreas Winter; Appeared in: IEEE Transactions on Information Theory Publication date: Sep 2017, volume: 63, issue:9, pages: 5603 - 5617 Publisher: IEEE
» Constant Current Fast Charging of Electric Vehicles via a DC Grid Using a Dual-Inverter Drive
 Abstract:Existing integrated chargers are configured to charge from single- or three-phase ac networks. With the rapid emergence of dc grids, there is growing interest in the development of high-efficiency low-cost integrated chargers interfaced with dc power outlets. This paper introduces a new integrated charger offering electric vehicle fast charging from emerging dc distribution networks. In absence of a dc grid, the charger can alternatively be fed from a simple uncontrolled rectifier. The proposed charger leverages the dual-inverter topology previously developed for high-speed drive applications. By connecting the charger inlet to the differential ends of the traction inverters, charging is enabled for a wide battery voltage range previously unattainable using an integrated charger based on the single traction drive. An 11-kW experimental setup demonstrates rapid charging using constant current control and energy balancing of dual storage media. To minimize the harmonic impact of the charger on the dc distribution network, a combination of complementary and interleaved switching methods is demonstrated. Autors: Ruoyun Shi;Sepehr Semsar;Peter W. Lehn; Appeared in: IEEE Transactions on Industrial Electronics Publication date: Sep 2017, volume: 64, issue:9, pages: 6940 - 6949 Publisher: IEEE
» Constellation Design Enhancement for Color-Shift Keying Modulation of Quadrichromatic LEDs in Visible Light Communications
 Abstract:Quadrichromatic light-emitting diode (QLED) cluster is a four-color solid-state apparatus suitable for simultaneous illumination and communications. Unlike traditional red/green/blue (RGB) LEDs, its extra color provides not only one new wavelength-division multiplexing data channel but also better color quality in illumination. Taking full consideration of the high quality of color rendering index (CRI) requirement with tunable color temperature (CT), this paper investigates the constellation design of color shift keying (CSK) to maximize the minimum pairwise Euclidean distance (MED) for communication performance optimization. Beyond existing works, maintaining a high-level CRI with a specified CT complicates our design optimization problem. We propose to transform the CRI requirement into a set of linear constraints on one of the LED source composition while jointly incorporating the CT constraints. Both simulation results and prototype CSK communication testbed measurements based on commercial multicolor LEDs (LUMILEDS Luxeon C) illustrate that, under the same luminous flux and CT conditions, our proposed flux independent CSK constellation for QLEDs can significantly enhance the MED, bit error rate, and illumination color qualities. Autors: Xiao Liang;Ming Yuan;Jiaheng Wang;Zhi Ding;Ming Jiang;Chunming Zhao; Appeared in: Journal of Lightwave Technology Publication date: Sep 2017, volume: 35, issue:17, pages: 3650 - 3663 Publisher: IEEE
» Construction $\pi _{A}$ and $\pi _{D}$ Lattices: Construction, Goodness, and Decoding Algorithms
 Abstract:A novel construction of lattices is proposed. This construction can be thought of as a special class of Construction A from codes over finite rings that can be represented as the Cartesian product of linear codes over , respectively, and hence is referred to as Construction . The existence of a sequence of such lattices that is good for channel coding (i.e., Poltyrev-limit achieving) under multistage decoding is shown. A new family of multilevel nested lattice codes based on Construction lattices is proposed and its achievable rate for the additive white Gaussian noise channel is analyzed. A generalization named Construction is also investigated, which subsumes Construction A with codes over prime fields, Construction D, and Construction as special cases. Autors: Yu-Chih Huang;Krishna R. Narayanan; Appeared in: IEEE Transactions on Information Theory Publication date: Sep 2017, volume: 63, issue:9, pages: 5718 - 5733 Publisher: IEEE
» Construction of Highly Nonlinear 1-Resilient Boolean Functions With Optimal Algebraic Immunity and Provably High Fast Algebraic Immunity
 Abstract:In 2013, Tang, Carlet, and Tang [IEEE TIT 59(1): 653–664, 2013] presented two classes of Boolean functions. The functions in the first class are unbalanced and the functions in the second one are balanced. Both of those two classes of functions have high nonlinearity, high algebraic degree, optimal algebraic immunity, and high fast algebraic immunity. However, they are not 1-resilient which represents a drawback for their use as filter functions in stream ciphers. In this paper, we first propose a large family of 1-resilient Boolean functions having high lower bound on nonlinearity, optimal algebraic immunity, and optimal algebraic degree, that is, meeting the Siegenthaler bound. Most notably, we can mathematically prove that every function in variables belonging to this family has fast algebraic immunity no less than , which is the first time that an infinite family of 1-resilient functions with provably high fast algebraic immunity has been invented. Furthermore, we exhibit a subclass of the family which has higher lower bound on nonlinearity than all the known 1-resilient functions with (potentially) optimal algebraic immunity and potentially high fast algebraic immunity. Autors: Deng Tang;Claude Carlet;Xiaohu Tang;Zhengchun Zhou; Appeared in: IEEE Transactions on Information Theory Publication date: Sep 2017, volume: 63, issue:9, pages: 6113 - 6125 Publisher: IEEE
» Continued Dispute on Preferred Vehicle-to-Vehicle Technologies [Connected Vehicles]
 Abstract:As reported in the June issue of IEEE Vehicular Technology Magazine [1], the National Highway Traffic Safety Administration (NHTSA) Department of Transportation has issued a proposed rule, "The Federal Motor Vehicle Safety Standard (FMVSS); Vehicle-to-Vehicle (V2V) Communications," that would require automakers to include V2V technologies in all new light-duty vehicles. The proposed rule was open for public comments until 12 April and received several replies, which were most notably from four different stakeholders, reflecting the still-ongoing heated debate about sharing the intelligent transport systems (ITS) frequency band in the United States. Autors: Elisabeth Uhlemann; Appeared in: IEEE Vehicular Technology Magazine Publication date: Sep 2017, volume: 12, issue:3, pages: 17 - 20 Publisher: IEEE
» Continuous Estimation of Human Multi-Joint Angles From sEMG Using a State-Space Model
 Abstract:Due to the couplings among joint-relative muscles, it is a challenge to accurately estimate continuous multi-joint movements from multi-channel sEMG signals. Traditional approaches always build a nonlinear regression model, such as artificial neural network, to predict the multi-joint movement variables using sEMG as inputs. However, the redundant sEMG-data are always not distinguished; the prediction errors cannot be evaluated and corrected online as well. In this work, a correlation-based redundancy-segmentation method is proposed to segment the sEMG-vector including redundancy into irredundant and redundant subvectors. Then, a general state-space framework is developed to build the motion model by regarding the irredundant subvector as input and the redundant one as measurement output. With the built state-space motion model, a closed-loop prediction-correction algorithm, i.e., the unscented Kalman filter (UKF), can be employed to estimate the multi-joint angles from sEMG, where the redundant sEMG-data are used to reject model uncertainties. After having fully employed the redundancy, the proposed method can provide accurate and smooth estimation results. Comprehensive experiments are conducted on the multi-joint movements of the upper limb. The maximum RMSE of the estimations obtained by the proposed method is 0.16±0.03, which is significantly less than 0.25±0.06 and 0.27±0.07 (p < 0.05) obtained by common neural networks. Autors: Qichuan Ding;Jianda Han;Xingang Zhao; Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering Publication date: Sep 2017, volume: 25, issue:9, pages: 1518 - 1528 Publisher: IEEE
» Control of Mutual Coupling in High-Field MRI Transmit Arrays in the Presence of High-Permittivity Liners
 Abstract:In high-field magnetic resonance imaging, transmit arrays and high-permittivity inserts are often used together to mitigate the effects of RF field inhomogeneities due to short wavelength. However, array performance is limited by mutual impedance between elements which must be closely spaced around the volume of interest. Mutual impedance plays a substantial role at high frequencies and is increased by the presence of dielectric pads which are used to increase the homogeneity of the RF magnetic field. This paper describes a decoupling strategy for an eight-channel transmit/receive array in the presence of a high permittivity dielectric liner. The elements are decoupled using capacitive bridges between adjacent elements. In spite of the higher mutual impedance due to the liner, both mutual resistance and reactance can be removed between adjacent elements (isolation better than 30 dB), and coupling between nonadjacent elements is maintained below 15 dB. The effects of decoupling on the transmit performance of the array in presence of high permittivity liners are investigated in terms of coupling, magnetic field intensity, SAR and transmit efficiencies. Autors: Atefeh Kordzadeh;Nicola De Zanche; Appeared in: IEEE Transactions on Microwave Theory and Techniques Publication date: Sep 2017, volume: 65, issue:9, pages: 3485 - 3491 Publisher: IEEE
» Control of Widely Tunable Lasers With High-Q Resonator as an Integral Part of the Cavity
 Abstract:We have designed and fabricated widely tunable semiconductor laser with a high-Q resonator as an integral part of the laser cavity. Wide tuning is realized by utilizing the Vernier effect of two rings with slightly different circumferences. A third ring with considerably larger circumference, and, consequently, higher Q is introduced inside the laser cavity. We study the control of such a laser and show that it is straightforward provided that the integrated laser has on-chip monitor photodiodes. This further shows the benefits of full integration as inclusion of additional monitor photodetectors is straightforward with no extra processing steps. As the complexity of photonic-integrated chips increases, the inclusion of more monitor photodetectors for control is necessary. Autors: Tin Komljenovic;Songtao Liu;Erik Norberg;Gregory A. Fish;John E. Bowers; Appeared in: Journal of Lightwave Technology Publication date: Sep 2017, volume: 35, issue:18, pages: 3934 - 3939 Publisher: IEEE
» Control Strategy to Eliminate Impact of Voltage Measurement Errors on Grid Current Performance of Three-Phase Grid-Connected Inverters
 Abstract:This study proposes an advanced current control strategy for three-phase grid-connected inverters to reject the impact of the dc offsets and scaling errors in the grid voltage measurement on the grid current performance. The proposed current controller designed in the synchronous (d-q) reference frame is developed with a proportional integral (PI) plus three vector PI controllers. The PI controller regulates the fundamental current to follow its reference, meanwhile, three vector PI controllers tuned at the fundamental grid frequency (), , are employed to eliminate the dc, unbalance, harmonic components in the grid current. As a result, the three-phase grid currents are controlled to be balanced, sinusoidal, and extremely low dc component despite the presence of the dc offset and scaling errors in the grid voltage measurement and distorted grid voltage conditions. The main advantage of the proposed control scheme is that it is developed without the need of additional hardware circuit, dc extraction, and harmonic detection scheme so that it can be integrated into the existing grid-connected inverter system without extra cost. The effectiveness of the suggested solution is verified by experimental results under various grid voltage conditions and the grid voltage measurement errors. Autors: Quoc-Nam Trinh;Fook Hoong Choo;Peng Wang; Appeared in: IEEE Transactions on Industrial Electronics Publication date: Sep 2017, volume: 64, issue:9, pages: 7508 - 7519 Publisher: IEEE
» Controller-centric combinatorial wrap-around interaction testing to evaluate a stateful PCE-based transport network architecture
 Abstract:The objective of this paper is to develop a controller-centric combinatorial wrap-around interaction testing methodology for a stateful path computation element (PCE)-based transport network architecture. By exploiting the internal contexts of the controller-centric network in conjunction with combinatorial, wrap-around, and interaction testing methodologies, the proposed testing methodology helps test engineers build a highly configurable testing environment, select high-quality test cases to obtain the best possible combination of interactions, and prune fault cases or useless cases from all possible test cases throughout the entire development process as gray-box testing. The experimental results verify that the combined testing methodology effectively evaluates the controller-centric network for all testing processes in a completely controlled environment. Autors: Jin Seek Choi; Appeared in: IEEE/OSA Journal of Optical Communications and Networking Publication date: Sep 2017, volume: 9, issue:9, pages: 792 - 802 Publisher: IEEE
» Controlling Soft Robots: Balancing Feedback and Feedforward Elements
 Abstract:Soft robots (SRs) represent one of the most significant recent evolutions in robotics. Designed to embody safe and natural behaviors, they rely on compliant physical structures purposefully designed to embody desirable and sometimes variable impedance characteristics. This article discusses the problem of controlling SRs. We start by observing that most of the standard methods of robotic control-e.g., high-gain robust control, feedback linearization, backstepping, and active impedance control-effectively fight against or even completely cancel the physical dynamics of the system, replacing them with a desired model. This defeats the purpose of introducing physical compliance. After all, what is the point of building soft actuators if we then make them stiff by control? Autors: Cosimo Della Santina;Matteo Bianchi;Giorgio Grioli;Franco Angelini;Manuel Catalano;Manolo Garabini;Antonio Bicchi; Appeared in: IEEE Robotics & Automation Magazine Publication date: Sep 2017, volume: 24, issue:3, pages: 75 - 83 Publisher: IEEE
» Cooperation of Wind Power and Battery Storage to Provide Frequency Regulation in Power Markets
 Abstract:In the future power system with high penetration of renewables, renewable energy is expected to undertake part of the responsibility for frequency regulation, just as the conventional generators. Wind power and battery storage are complementary in accuracy and durability when providing frequency regulation. Therefore, it would be profitable to combine wind power and battery storage as a physically connected entity or a virtual power plant to provide both energy and frequency regulation in the markets. This paper proposes a real-time cooperation scheme to exploit their complementary characteristics and an optimal bidding strategy for them in joint energy and regulation markets, considering battery cycle life. The proposed cooperation scheme is adopted in a real-time battery operating simulation and then incorporated into the optimal bidding model. The scheme could improve the wind regulation performance score and allow for more regulation bids without affecting the battery life, thus significantly increasing the overall revenue. The validity of the proposed scheme and strategy are proved by the case study. Autors: Guannan He;Qixin Chen;Chongqing Kang;Qing Xia;Kameshwar Poolla; Appeared in: IEEE Transactions on Power Systems Publication date: Sep 2017, volume: 32, issue:5, pages: 3559 - 3568 Publisher: IEEE
» Cooperation-Based Probabilistic Caching Strategy in Clustered Cellular Networks
 Abstract:This letter will discuss the probabilistic caching strategies in spatially clustered cellular networks. Thanks to the content preference of mobile users, proactive caching can be adopted as a promising technique to diminish the backhaul traffic and to decrease the content delivery latency. However, basically there are two obstacles to accomplish the caching policy, i.e., the limited storage capacity of small cells to cache large amount of multimedia contents, and the too small number of users under each base station to imply the content aggregation effect. Traditional caching strategies of the base station only concern its local requests from the connected users through wireless links, but neglect the potential benefit from the cluster feature of the network infrastructure and user traffic demand. In this letter, we proposed a new policy called "Caching as a Cluster", where small cells can exchange content with each other to fulfill every user request within the cluster of base stations. Intuitively, this cooperation between base stations makes a difference to decrease the content delivery latency of mobile users in clustered cellular networks as testified in our numerical simulation. Autors: Yifan Zhou;Zhifeng Zhao;Rongpeng Li;Honggang Zhang;Yves Louet; Appeared in: IEEE Communications Letters Publication date: Sep 2017, volume: 21, issue:9, pages: 2029 - 2032 Publisher: IEEE
» Cooperation-Driven Distributed Control Scheme for Large-Scale Wind Farm Active Power Regulation
 Abstract:Being more actively involved in the electricity market and power systems, wind farms are urgently expected to have similar controllable behavior to conventional generations so that demand assigned by the system operator can be met. However, determining the method of dispatching the reference among the widely spread and low-rating wind turbines is difficult. This paper provides a cooperation-driven distributed control scheme for wind farm active power regulation. Instead of competing with neighboring controllers completely, the control strategy evaluates system-wide impacts of local control actions, and aims to achieve coordinated control effect. In addition, the kinetic energy storage potential in a wind turbine is tapped to provide a buffer for power dispatch. Case studies demonstrate that a large wind farm can be effectively controlled to accurately track the demand power through the proposed control scheme. Autors: Xiaodan Gao;Ke Meng;Zhao Yang Dong;Dongxiao Wang;Mohamed Shawky El Moursi;Kit Po Wong; Appeared in: IEEE Transactions on Energy Conversion Publication date: Sep 2017, volume: 32, issue:3, pages: 1240 - 1250 Publisher: IEEE
» Cooperative Jamming for Secure Communication With Finite Alphabet Inputs
 Abstract:This letter considers cooperative jamming to secure communication in the presence of multiple eavesdroppers with finite alphabet inputs. Considering the global constraint, the joint design of artificial noise covariance matrices and power allocation between the source and the relays is studied. Specifically, we transformed the problem of artificial noise design into a semi-definite programming problem, which is efficiently solved by standard optimization method. Besides, the power allocation between the source and relays is derived by utilizing the relationship between mutual information and minimum mean square error. Furthermore, a two-step algorithm is developed to enhance the achievable secrecy rate of cooperative jamming wireless network. Numerical examples demonstrate the proposed algorithm achieves a significant gain over the conventional counterparts in terms of secrecy rate. Autors: Kuo Cao;Yueming Cai;Yongpeng Wu;Weiwei Yang; Appeared in: IEEE Communications Letters Publication date: Sep 2017, volume: 21, issue:9, pages: 2025 - 2028 Publisher: IEEE
» Cooperative Multicast With Location Aware Distributed Mobile Relay Selection: Performance Analysis and Optimized Design
 Abstract:Mobile relay (MR) selection is critical to the performance and realization of two-stage cooperative multicast (CM). Targeting at the energy efficiency and simplified realization, a location-aware distributed (LAD) MR selection method is proposed, where successful mobile stations (MSs) at the first stage that are farther from the base station would activate themselves to be MRs with higher probabilities. Assuming that the number of MRs close to an unsuccessful MS follows Poisson Point Process distribution, based on stochastic geometry, the coverage performance of two-stage CM with LAD MR selection can be numerically evaluated. Moreover, given the analytical results, an optimized LAD MR selection scheme can be designed, aiming at minimizing the total power consumption of two-stage CM. Numerical and simulation results verify that the analysis based on stochastic geometry is accurate. Overall, the optimized LAD MR scheme provides better energy efficiency and coverage performance than existing distributed MR schemes. Autors: Yiqing Zhou;Hang Liu;Zhengang Pan;Lin Tian;Jinglin Shi; Appeared in: IEEE Transactions on Vehicular Technology Publication date: Sep 2017, volume: 66, issue:9, pages: 8291 - 8302 Publisher: IEEE
» Coordinated Control Strategies for Offshore Wind Farm Integration via VSC-HVDC for System Frequency Support
 Abstract:Coordinated control strategies to provide system inertia support for main grid from offshore wind farm that is integrated through HVdc transmission is the subject matter of this paper. The strategy that seeks to provide inertia support to the main grid through simultaneous utilization of HVdc capacitors energy, and wind turbines (WTs) inertia without installing the remote communication of two HVdc terminals is introduced in details. Consequently, a novel strategy is proposed to improve system inertia through sequentially exerting dc capacitors energy and then WTs inertia via a cascading control scheme. Both strategies can effectively provide inertia support while the second one minimizes the control impacts on harvesting wind energy with the aid of communication between onshore and offshore ac grids. Case studies of a wind farm connecting with a HVdc system considering sudden load variations have been successfully conducted to compare and demonstrate the effectiveness of the control strategies in DIgSILENT/PowerFactory. Autors: Yujun Li;Zhao Xu;Jacob Østergaard;David J. Hill; Appeared in: IEEE Transactions on Energy Conversion Publication date: Sep 2017, volume: 32, issue:3, pages: 843 - 856 Publisher: IEEE
» Coordinated Multi-Area Economic Dispatch via Critical Region Projection
 Abstract:A coordinated economic dispatch method for multiarea power systems is proposed. Choosing boundary phase angles as coupling variables, the proposed method exploits the structure of critical regions in local problems defined by active and inactive constraints. For a fixed boundary state given by the coordinator, local operators compute the coefficients of critical regions containing the boundary state and the optimal value functions then communicate them to the coordinator who in turn optimizes the boundary state to minimize the overall cost. By iterating between local operators and the coordinator, the proposed algorithm converges to the global optimal solution in finite steps, and it requires limited information sharing. Autors: Ye Guo;Lang Tong;Wenchuan Wu;Boming Zhang;Hongbin Sun; Appeared in: IEEE Transactions on Power Systems Publication date: Sep 2017, volume: 32, issue:5, pages: 3736 - 3746 Publisher: IEEE
» Coordination Over Multi-Agent Networks With Unmeasurable States and Finite-Level Quantization
 Abstract:In this note, the coordination of linear discrete-time multi-agent systems over digital networks is investigated with unmeasurable states in agents' dynamics. The quantized-observer based communication protocols and Certainty Equivalence principle based control protocols are proposed to characterize the inter-agent communication and the cooperative control in an integrative framework. By investigating the structural and asymptotic properties of the equations of stabilization and estimation errors, which are nonlinearly coupled by the finite-level quantization scheme, some necessary conditions and sufficient conditions are given for the existence of such communication and control protocols to ensure the inter-agent state observation and cooperative stabilization. It is shown that these conditions come down to the simultaneous stabilizability and the detectability of the dynamics of agents and the structure of the communication network. Autors: Yang Meng;Tao Li;Ji-Feng Zhang; Appeared in: IEEE Transactions on Automatic Control Publication date: Sep 2017, volume: 62, issue:9, pages: 4647 - 4653 Publisher: IEEE
» CoRQ: Enabling Runtime Reconfiguration Under WCET Guarantees for Real-Time Systems
 Abstract:Real-time systems have an increasing demand for predictable performance. Only recently novel models and analyses were proposed that make the performance benefits of runtime-reconfigurable architectures accessible for optimized worst-case execution time (WCET) guarantees. However, the implicit assumption in these works is that the process of reconfiguration itself complies with execution time guarantees. The realization of a reconfiguration controller that fulfills these assumptions and that is amenable to WCET guarantees is so far unavailable. In this letter, we detail the challenges of runtime reconfiguration in real-time systems and show that conflicts while accessing a shared main memory during reconfiguration can lead to a slowdown of more than in reconfiguration bandwidth. We present concepts that enable runtime reconfiguration under WCET guarantees and release our implementation of these concepts as open source. Autors: Marvin Damschen;Lars Bauer;Jörg Henkel; Appeared in: IEEE Embedded Systems Letters Publication date: Sep 2017, volume: 9, issue:3, pages: 77 - 80 Publisher: IEEE
» Correcting Instrumental Variation and Time-Varying Drift Using Parallel and Serial Multitask Learning
 Abstract:When instruments and sensor systems are used to measure signals, the posterior distribution of test samples often drifts from that of the training ones, which invalidates the initially trained classification or regression models. This may be caused by instrumental variation, sensor aging, and environmental change. We introduce transfer-sample-based multitask learning (TMTL) to address this problem, with a special focus on applications in machine olfaction. Data collected with each device or in each time period define a domain. Transfer samples are the same group of samples measured in every domain. They are used by our method to share knowledge across domains. Two paradigms, parallel and serial transfer, are designed to deal with different types of drift. A dynamic model strategy is proposed to predict samples with known acquisition time. Experiments on three real-world data sets confirm the efficacy of the proposed methods. They achieve good accuracy compared with traditional feature-level drift correction algorithms and typical labeled-sample-based MTL methods, with few transfer samples needed. TMTL is a practical algorithm framework which can greatly enhance the robustness of sensor systems with complex drift. Autors: Ke Yan;David Zhang;Yong Xu; Appeared in: IEEE Transactions on Instrumentation and Measurement Publication date: Sep 2017, volume: 66, issue:9, pages: 2306 - 2316 Publisher: IEEE
» Correction to “Automatic Quality Assessment of Echocardiograms Using Convolutional Neural Networks: Feasibility on the Apical Four-Chamber View”
 Abstract:In the above paper [1], the first footnote should have indicated the following information: A. H. Abdi and C. Luong are joint first authors. Autors: A. H. Abdi;C. Luong;T. Tsang;G. Allan;S. Nouranian;J. Jue;D. Hawley;S. Fleming;K. Gin;J. Swift;R. Rohling;P. Abolmaesumi; Appeared in: IEEE Transactions on Medical Imaging Publication date: Sep 2017, volume: 36, issue:9, pages: 1992 - 1992 Publisher: IEEE
» Correction to “Fast Mode Selection for HEVC Intra-Frame Coding With Entropy Coding Refinement Based on a Transparent Composite Model”
 Abstract:After our internal code cross-check, we have recently found some mistakes in [1, Table VIII] and [1, Figs. 12 and 13]. As such, we have reimplemented the ideas and methods stated in [1]. The corrected Table VIII and Figs. 12 and 13 are now shown in this correction. Our code is also available from http://multicom.uwaterloo.ca. To reflect this correction, the following changes have to be made accordingly throughout the paper [1]. Autors: Nan Hu;En-Hui Yang; Appeared in: IEEE Transactions on Circuits and Systems for Video Technology Publication date: Sep 2017, volume: 27, issue:9, pages: 2055 - 2056 Publisher: IEEE
» Corrections on “Symbol Flipping Decoding Algorithms Based on Prediction for Non-Binary LDPC Codes”
 Abstract:Due to a production error, an equation in the above paper [1] appeared incorrectly. Below is the correct version. Autors: S. Wang;Q. Huang;Z. Wang; Appeared in: IEEE Transactions on Communications Publication date: Sep 2017, volume: 65, issue:9, pages: 4099 - 4099 Publisher: IEEE
» Corrections to “A 10/20/30/40 MHz Feed-Forward FIR DAC Continuous-Time $\Delta \Sigma$ ADC With Robust Blocker Performance for Radio Receivers”
 Abstract:In [1], Table I compares the state of the art in CT ADCs. Unfortunately, due to a mistake, the FOM [Schreier] (dB) reported is 3 dB below its actual value. Table I in [1] is reprinted as Table I. The authors regret their mistake. Autors: Sebastian Loeda;Jeffrey Harrison;Franck Pourchet;Andrew Adams; Appeared in: IEEE Journal of Solid-State Circuits Publication date: Sep 2017, volume: 52, issue:9, pages: 2515 - 2515 Publisher: IEEE
» Corrections to “Multilevel MVDC Link Strategy of High-Frequency-Link DC Transformer Based on Switched Capacitor for MVDC Power Distribution”
 Abstract:Presents corrections to the paper, “Multilevel MVDC Link Strategy of High-Frequency-Link DC Transformer Based on Switched Capacitor for MVDC Power Distribution,” (Wang, Y., et al), IEEE Trans. Ind. Electron. vol. 64, no. 4, pp. 2829–2835, Apr. 2017. Autors: Yu Wang;Qiang Song;Qianhao Sun;Biao Zhao;Jianguo Li;Wenhua Liu; Appeared in: IEEE Transactions on Industrial Electronics Publication date: Sep 2017, volume: 64, issue:9, pages: 7280 - 7280 Publisher: IEEE
» Corrections to “Fundamental Efficiency Limits for Small Metallic Antennas”
 Abstract:In [1], it was stated that “An attempt to establish bounds on the maximum achievable gain and efficiency using a “loss merit factor” is reported in [2]. However, the results are clearly unphysical, since a single turn loop antenna can surpass these fundamental limits when ” [3]. Autors: Carl Pfeiffer; Appeared in: IEEE Transactions on Antennas and Propagation Publication date: Sep 2017, volume: 65, issue:9, pages: 4958 - 4958 Publisher: IEEE
» Corrections to “Resource Allocation for D2D-Enabled Vehicular Communications”
 Abstract:In the above paper [1], the text discussion of several equations were misrepresented. Below is the corrected text of Sections III and IV, in which the errors appear. Autors: L. Liang;G. Y. Li;W. Xu; Appeared in: IEEE Transactions on Communications Publication date: Sep 2017, volume: 65, issue:9, pages: 4096 - 4098 Publisher: IEEE
» Correntropy Maximization via ADMM: Application to Robust Hyperspectral Unmixing
 Abstract:In hyperspectral images, some spectral bands suffer from low signal-to-noise ratio due to noisy acquisition and atmospheric effects, thus requiring robust techniques for the unmixing problem. This paper presents a robust supervised spectral unmixing approach for hyperspectral images. The robustness is achieved by writing the unmixing problem as the maximization of the correntropy criterion subject to the most commonly used constraints. Two unmixing problems are derived: the first problem considers the fully constrained unmixing, with both the nonnegativity and sum-to-one constraints, while the second one deals with the nonnegativity and the sparsity promoting of the abundances. The corresponding optimization problems are solved using an alternating direction method of multipliers (ADMM) approach. Experiments on synthetic and real hyperspectral images validate the performance of the proposed algorithms for different scenarios, demonstrating that the correntropy-based unmixing with ADMM is particularly robust against highly noisy outlier bands. Autors: Fei Zhu;Abderrahim Halimi;Paul Honeine;Badong Chen;Nanning Zheng; Appeared in: IEEE Transactions on Geoscience and Remote Sensing Publication date: Sep 2017, volume: 55, issue:9, pages: 4944 - 4955 Publisher: IEEE
» Cost-Effective Enhancement on Both Yield and Reliability for Cache Designs Based on Performance Degradation Tolerance
 Abstract:Guaranteeing functional correctness of cache memories is crucial for computer designs. In the literature, there have been several works addressing this issue. However, fault tolerability of these methods may be limited. In this paper, we present a new cache architecture that has flexible tolerability. Moreover, by using the proposed architecture, both yield and reliability of the cache can be enhanced simultaneously. In our cache, a particular type of cache blocks called tolerable block is further identified among the faulty ones. Such blocks can still be used during cache access in our architecture, while accessing to intolerable blocks will result in additional cache misses, and therefore performance degradation. The number of tolerable cache blocks is thus critical for the achievable yield and reliability enhancement, as well as the incurred cost on performance. In this work, error correcting code (ECC) methods are employed to increase the number of tolerable blocks. In particular, we propose to embed the required check bits in one of the cache ways. Analysis results show that this embedding method only incurs minor performance degradation, while the incurred area overhead due to ECC can thus be significantly reduced from 5.92% to only 0.92%. General applicability of the embedding method to ordinary ECC methods is also investigated. Experimental results show that the performance degradation can be reduced from 16% to only 1.53% by using the proposed cache. This leads to great tolerability improvement, and thus the yield and reliability are enhanced very significantly when compared with the previous work. Autors: Tong-Yu Hsieh;Tsung-Liang Chih;Mei-Jung Wu; Appeared in: IEEE Transactions on Very Large Scale Integration Systems Publication date: Sep 2017, volume: 25, issue:9, pages: 2434 - 2448 Publisher: IEEE
» Cost-Efficient Cellular Networks Powered by Micro-Grids
 Abstract:This paper investigates a cellular network powered by a micro-grid (MG) in the context of green communications, which integrates the conventional generators, energy storage devices, and renewable energy generators, so as to supply electricity to base stations (BSs). Under this model, we study the efficiency aspect of the MG-powered cellular network from the economical perspective. Specifically, the concept of cost efficiency (CE) is employed to measure the sum rate delivered per dollar. Then, our goal is to maximize this CE subject to a series of constraints, including multi-variable coupling and time coupling constraints. Particularly, we assume the zero-forcing beamforming scheme employed by the BSs. To address this established fractional CE optimization problem, we first apply the Dinkelbach method, and then propose a low-complexity algorithm based on the alternating direction method of multipliers approach to jointly schedule power generation in the MG and optimize transmit power for BSs. We introduce a number of auxiliary variables to design a special variable splitting scheme so that the coupling inequality constraints can be separable among two variable sets. Consequently, the proposed algorithm only incorporates simple updates in each step and thus can be implemented in a parallel and completely distributed fashion. Simulation results demonstrate the convergence and energy scheduling performance of the proposed algorithm. Autors: Ling Zhang;Yunlong Cai;Qingjiang Shi;Guanding Yu;Geoffrey Ye Li; Appeared in: IEEE Transactions on Wireless Communications Publication date: Sep 2017, volume: 16, issue:9, pages: 6047 - 6061 Publisher: IEEE
» Coupled Split-Ring Resonator Circular Polarization Selective Surface
 Abstract:A novel class of circular polarization selective surfaces (CPSSs) consisting of a pair of planar split-ring resonator arrays is proposed. A significant advantage of the proposed structure over existing designs is its manufacturing simplicity compatible with standard printed technology processes. Its operating principle is reviewed alongside that of the Pierrot cell and in light of the linear polarization reflection and transmission characteristics of CPSSs. Guidelines for the initial design of the proposed CPSS concept are thus derived. Further design considerations and tradeoffs are also discussed. The validity of the concept is confirmed by means of a design example entailing a right-hand CPSS at 20 GHz. Full-wave simulation results and experimental testing on a fabricated prototype are presented and agree well with the theoretical predictions. Autors: Wenxing Tang;George Goussetis;Nelson J. G. Fonseca;Hervé Legay;Elena Sáenz;Peter de Maagt; Appeared in: IEEE Transactions on Antennas and Propagation Publication date: Sep 2017, volume: 65, issue:9, pages: 4664 - 4675 Publisher: IEEE
» Coupling Quality [Enigmas, etc.]
 Abstract:Various puzzles, games, humorous definitions, or mathematical that should engage the interest of readers. Autors: Takashi Ohira; Appeared in: IEEE Microwave Magazine Publication date: Sep 2017, volume: 18, issue:6, pages: 154 - 154 Publisher: IEEE
» Coverage Contribution Area Based $k$ -Coverage for Wireless Sensor Networks
 Abstract:Coverage is a primary metric for ensuring the quality of services provided by a wireless sensor network (WSN). In this paper, we focus on the -coverage problem, which requires a selection of a minimum subset of nodes among the deployed ones such that each point in the target region is covered by at least nodes. We present both centralized and distributed protocols to tackle this fundamental problem. Our protocols are based on a novel concept of Coverage Contribution Area, which helps to get a lower sensor spatial density. Furthermore, our protocols take the residual energies of the sensors into consideration. This consideration combined with the low sensor spatial density ensures that our protocols can prolong the network lifetime to a greater extent, which is crucial to WSNs due to the limited energy supply and the difficulties of energy recharging. We also conduct extensive simulations to verify our proposed algorithms, and the results show that they are superior over existing ones. Autors: Jiguo Yu;Shengli Wan;Xiuzhen Cheng;Dongxiao Yu; Appeared in: IEEE Transactions on Vehicular Technology Publication date: Sep 2017, volume: 66, issue:9, pages: 8510 - 8523 Publisher: IEEE
» Covert Communication in the Presence of an Uninformed Jammer
 Abstract:Recent work has established that when transmitter Alice wishes to communicate reliably to recipient Bob without detection by warden Willie, with additive white Gaussian noise (AWGN) channels between all parties, communication is limited to bits in channel uses. However, this assumes that Willie has an accurate statistical characterization of the channel. When Willie has uncertainty about such and his receiver is limited to a threshold test on the received power, Alice can transmit covertly with a power that does not decrease with , thus conveying bits covertly and reliably in uses of an AWGN channel. Here, we consider covert communication of bits in channel uses while generalizing the environment and removing any restrictions on Willie’s receiver. We assume that an uninformed “jammer” is present to help Alice, and we consider AWGN and block fading channels. In some scenarios, Willie’s optimal detector is a threshold test on the received power. When the channel between the jammer and Willie has multiple fading blocks per codeword, a threshold test on the received power is not optimal. However, we establish that Alice can remain covert with a transmit power that does not decrease with even when Willie employs an optimal detector. Autors: Tamara V. Sobers;Boulat A. Bash;Saikat Guha;Don Towsley;Dennis Goeckel; Appeared in: IEEE Transactions on Wireless Communications Publication date: Sep 2017, volume: 16, issue:9, pages: 6193 - 6206 Publisher: IEEE
» Critical Analysis of Model-Based Incoherent Polarimetric Decomposition Methods and Investigation of Deorientation Effect
 Abstract:This paper critically analyzes several incoherent model-based decomposition methods for assessing the effect of deorientation in characterization of various land covers. It has been found that even after performing decomposition, ambiguity still occurs in scattering response from various land covers, such as urban and vegetation. Researchers introduced the concept of deorientation to remove this ambiguity. Therefore, in this paper, a critical analysis has been carried out using seven different three- and four-component decomposition methods with and without deorientation and two Eigen decomposition-based methods to investigate the scattering response on various land covers, such as urban, vegetation, bare soil, and water. The comprehensive evaluation of decomposition and deorientation effect has been performed by both visual and quantitative analyses. Two types of quantitative analysis have been performed; first, by observing percentage of scattering power and second, by analyzing the variation in the number of pixels in different land covers for each scattering contribution. The analysis shows that deorientation increases not only the power but also the number of pixels for surface and double bounce scattering. The number of pixels representing volume scattering remain almost the same for all the methods with or without deorientation, whereas volume scattering power reduces after deorientation. Eigen decomposition-based methods are observed to solve the problem of overestimation of volume scattering power. Autors: Pooja Mishra;Akanksha Garg;Dharmendra Singh; Appeared in: IEEE Transactions on Geoscience and Remote Sensing Publication date: Sep 2017, volume: 55, issue:9, pages: 4868 - 4877 Publisher: IEEE
» Critical Bus Voltage Support in Distribution Systems With Electric Springs and Responsibility Sharing
 Abstract:With the development of a new smart load device, the electric spring (ES), the operation of distribution systems with high renewable penetration becomes more flexible. The ESs can be installed at noncritical loads for grid support. This paper proposes a two-level voltage management scheme to optimize the voltage profiles of the network, especially at chosen critical buses. In the upper level, the tap positions of load tap changer and capacitor banks switching are optimized to prevent the voltages along the feeder from being out of limits. The model predictive control technique is applied to handle the uncertainties in renewable energy and demand. In the lower level, the responsibility of maintaining the voltages of the critical buses is shared among the ES in a distributed way via consensus control which is suitable for systems with limited communication and calculation capabilities. The proposed management scheme is verified on a modified IEEE 15-bus distribution network. The results show that different voltage regulation devices can work together to maintain the voltage of critical buses by sharing the responsibility in the proposed scheme. Autors: Yu Zheng;David John Hill;Ke Meng;S. Y. Hui; Appeared in: IEEE Transactions on Power Systems Publication date: Sep 2017, volume: 32, issue:5, pages: 3584 - 3593 Publisher: IEEE
» Cross-Range Resolution Enhancement for DBS Imaging in a Scan Mode Using Aperture-Extrapolated Sparse Representation
 Abstract:This letter addresses the problem of cross-range superresolution in Doppler beam sharpening (DBS). The coherence of echoes in the azimuth direction and the sparsity of the DBS image in the Doppler domain are fully exploited; thus, a superresolution DBS imaging framework using aperture-extrapolated sparse representation (SR) is proposed. In this framework, aperture extrapolation based on the autoregressive model is utilized to predict the forward and backward information in the azimuth direction, and SR is exploited to extract the Doppler spectrum information. In addition, the resolution ability with different coherent processing intervals is analyzed. The sharpening ratio in this proposed algorithm can be improved by a factor of two or four theoretically in comparison with the conventional DBS imaging method. Experimental results demonstrate that the proposed framework can lead to noticeable performance improvement. Autors: Hongmeng Chen;Ming Li;Zeyu Wang;Yunlong Lu;Runqing Cao;Peng Zhang;Lei Zuo;Yan Wu; Appeared in: IEEE Geoscience and Remote Sensing Letters Publication date: Sep 2017, volume: 14, issue:9, pages: 1459 - 1463 Publisher: IEEE
» Crystallinity of Silicon-Shells Deposited onto Germanium and Silicon Nanowires for Core-Shell Nanostructures and Nanotubes
 Abstract:Core-shell nanowires are an essential component of numerous nanoscale device concepts. In this study, germanium and silicon nanowires were synthesized bottom-up using the vapor-liquid-solid technique and successively modified with a silicon shell. The shell synthesis was studied with focus to the crystallinity but includes as well the electrical characteristics of n- and p-doped radial core-shell nanowire devices. Furthermore, the influence of certain post-annealing procedures on the crystallinity of the core-shell nanowires are discussed. We demonstrate that the crystallinity of the silicon shell can be tuned from single-crystalline to amorphous in a controlled manner, independent on a p- or n-type doping, by deliberate adjustment of the growth parameters. Autors: Ardeshir Moeinian;Nicolas Hibst;Dorin Geiger;Johannes Biskupek;Steffen Strehle; Appeared in: IEEE Transactions on Nanotechnology Publication date: Sep 2017, volume: 16, issue:5, pages: 736 - 740 Publisher: IEEE
» Current-Mode Triline Transceiver for Coded Differential Signaling Across On-Chip Global Interconnects
 Abstract:This paper presents a current-mode triline ternary-level coded differential signaling scheme for high-speed data transmission across on-chip global interconnects. An energy efficient current-mode triline transceiver pair suitable for this signaling scheme has been proposed. Compared with a voltage mode receiver with resistive termination, the proposed active terminated current-mode receiver reduces the signal current by 7.8 times and the signaling power by 2.6 times. Two data transmission schemes are proposed for using this transceiver pair. In the first scheme, two data streams are directly transmitted over the three lines link, thereby having a wire efficiency of 67%. In the second scheme, five data streams at half rate are encoded and serialized to send over the three lines, thereby having a wire efficiency of 83%. A prototype design has been implemented in a UMC 0.18- technology for an interconnect of length 5 mm. The measured energy efficiency of the triline transceiver in a direct transmission scheme for the data rate of 7.4 Gb/s is 0.61 pJ/bit. With the encoding scheme, the energy efficiency is 1.24 pJ/bit for a total data transmission of 9.25 Gb/s. Autors: Nijwm Wary;Pradip Mandal; Appeared in: IEEE Transactions on Very Large Scale Integration Systems Publication date: Sep 2017, volume: 25, issue:9, pages: 2575 - 2587 Publisher: IEEE
» Customers seek 100-percentrenewable grids [News]
 Abstract:In June, energy experts were clashing in both tweets and peer-reviewed journals over the feasibility of the United States achieving a 100-percent-renewable power grid in 2050. Many governments, utilities, and big consumers, however, appear unwilling to wait for the engineers' all clear: An increasing number of jurisdictions and institutions are setting deadlines for a jump to a 100- percent-renewable electricity grid or even beyond, to fossil- fuel-free heating and roadways as well. Autors: Peter Fairley; Appeared in: IEEE Spectrum Publication date: Sep 2017, volume: 54, issue:9, pages: 12 - 13 Publisher: IEEE
» CW Experiments With the EU 1-MW, 170-GHz Industrial Prototype Gyrotron for ITER at KIT
 Abstract:The European 1-MW, 170-GHz continuous wave industrial prototype gyrotron for electron cyclotron resonance heating and current drive on international thermonuclear experimental reactor was during 2016 under test at the Karlsruhe Institute of Technology (KIT) test facility. In order to optimize the gyrotron operation, the tube was at first thoroughly tested in the short-pulse regime, with pulses that did not exceed 10 ms, for a wide range of operational parameters. Then, and after proper conditioning of the tube, the operation was extended to longer pulses with duration up to 180 s, which is the maximum pulselength possible at the KIT test facility. In this paper, we present in detail the achievements of the long-pulse experimental campaign. Autors: Zisis C. Ioannidis;Tomasz Rzesnicki;F. Albajar;S. Alberti;Konstantinos A. Avramidis;William Bin;T. Bonicelli;Alessandro Bruschi;Ioannis Chelis;P.-E. Frigot;Gerd Gantenbein;V. Hermann;J.-P. Hogge;Stefan Illy;Jianbo Jin;John Jelonnek;W. Kasparek;G. Lat Appeared in: IEEE Transactions on Electron Devices Publication date: Sep 2017, volume: 64, issue:9, pages: 3885 - 3892 Publisher: IEEE
» Cyber-Medical Systems: Requirements, Components and Design Examples
 Abstract:Cyber-medical systems will produce a major revolution in health care, by both raising the quality of care and reducing its cost, thus reaching an important social and economic goal. The evolution of electronic devices and systems has already enabled societal changes. Inroads in the quantification of medicine, in the discovery and applications of biosensors in connection with integrated circuit technology, in the analysis of large-scale real-time biomedical data are strong indicators that cyber-medical systems will redesign health care in the years to come. To sustain this thesis, this paper presents three aspects of cyber-medical systems, describes their medical significance and potentials, and then delves in the detailed technology required to realize such systems. Specifically, this paper describes state of the art sensing devices and their integration into platforms, data processing for ultrasound medical imaging and system correctness approaches for drug administration support systems. The paper concludes with a brief outlook on the evolution of this emerging field in the years to come. Autors: Giovanni De Micheli; Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers Publication date: Sep 2017, volume: 64, issue:9, pages: 2226 - 2236 Publisher: IEEE
» Cybersecurity and Rural Electric Power Systems: Considering Competing Requirements for Implementing a Protection Plan
 Abstract:Cybersecurity is a topic of increasing importance and interest to small utility operators like rural electric associations. Cyberattacks are a threat to our society's functioning, and cybersecurity is an urgent need in areas that include national security, business operations, and regulatory compliance. Several fundamental concepts can guide an operator when implementing a cybersecurity plan. Operators must consider the competing requirements of confidentiality, integrity, availability (CIA), and cost. They must also consider the potential of impact levels for an incident. While implementing a cybersecurity plan, operators will constantly identify adversaries, threats, vulnerabilities, consequences, and risks. They will implement physical, technical, and administrative controls to protect networks and other assets, detect attacks, respond to those attacks, and recover from any damage. The process will be continuous as operators respond to the changing environment. Autors: Paul Kaster;Pankaj P.K. Sen; Appeared in: IEEE Industry Applications Magazine Publication date: Sep 2017, volume: 23, issue:5, pages: 14 - 20 Publisher: IEEE
» Cybersecurity in Power Systems
 Abstract:Did you know that cyberattackers have already created outages in Ukraine, not once but twice? On 23 December 2015, cyberintruders at three electric distribution companies in Ukraine opened breakers, creating a power outage that affected 225,000 people. Power was restored in approximately 6 h, as field personnel manually closed the breakers. Autors: Michael F. Ahern; Appeared in: IEEE Potentials Publication date: Sep 2017, volume: 36, issue:5, pages: 8 - 12 Publisher: IEEE
» Cyclostationary Stochastic Jitter Measurement Method With Uncertainty Prediction
 Abstract:This paper presents a completely new approach to measure the jitter at the output of a sample-and-hold circuit. A cyclostationary stochastic process is used to model the entire noise of the measurement system. This approach relies on the calculation of a cyclostationary variance, representing a complete description of the noise of the measurement system. This provides the basis for conducting powerful analyses of how the various noise sources contribute to the cyclostationary variance, enabling the user to gain a deep insight into the noise behavior of the system. A new jitter estimator is derived that provides some new and unprecedented features. First, it is robust against the second harmonic of the input signal, and second, it allows for the elimination of cyclostationary noise contributed by the data acquisition device. A stochastic model of the method is derived and a thorough analysis of the uncertainty of the proposed estimator is presented. This results in a formula that allows for the prediction of the measurement uncertainty and another formula that allows for the calculation of the required number of samples in order to meet a given uncertainty. The method proved to be accurate in Monte Carlo simulations and in measurements as well. A jitter in the range of 22 fs out of a 10-GS/s sample-and-hold integrated circuit was successfully measured with a standard deviation of 230 as. Autors: Thomas Schweiger;Benjamin Krüger;Frank Wiedmann; Appeared in: IEEE Transactions on Instrumentation and Measurement Publication date: Sep 2017, volume: 66, issue:9, pages: 2371 - 2379 Publisher: IEEE
» D2D-Aware Device Caching in mmWave-Cellular Networks
 Abstract:In this paper, we propose a novel policy for device caching that facilitates popular content exchange through high-rate device-to-device (D2D) millimeter-wave (mmWave) communication. The D2D-aware caching policy splits the cacheable content into two content groups and distributes it randomly to the user equipment devices, with the goal to enable D2D connections. By exploiting the high bandwidth availability and directionality of mmWaves, we ensure high rates for the D2D transmissions, while mitigating the co-channel interference that limits the throughput gains of the D2D communication in the sub-6-GHz bands. Furthermore, based on a stochastic-geometry modeling of the network topology, we analytically derive the offloading gain that is achieved by the proposed policy and the distribution of the content retrieval delay considering both half- and full-duplex modes for the D2D communication. The accuracy of the proposed analytical framework is validated through Monte Carlo simulations. In addition, for a wide range of a content popularity indicator, the results show that the proposed policy achieves higher offloading and lower content-retrieval delays than existing state-of-the-art approaches. Autors: Nikolaos Giatsoglou;Konstantinos Ntontin;Elli Kartsakli;Angelos Antonopoulos;Christos Verikoukis; Appeared in: IEEE Journal on Selected Areas in Communications Publication date: Sep 2017, volume: 35, issue:9, pages: 2025 - 2037 Publisher: IEEE
» Damping Methods for Resonances Caused by LCL-Filter-Based Current-Controlled Grid-Tied Power Inverters: An Overview
 Abstract:Grid-tied voltage source inverters using LCL filter have been widely adopted in distributed power generation systems (DPGSs). As high-order LCL filters contain multiple resonant frequencies, switching harmonics generated by the inverter and current harmonics generated by the active/passive loads would cause the system resonance, and thus the output current distortion and oscillation. Such phenomenon is particularly critical when the power grid is weak with the unknown grid impedance. In order to stabilize the operation of the DPGS and improve the waveform of the injected currents, many innovative damping methods have been proposed. A comprehensive overview on those contributions and their classification on the inverter- and grid-side damping measures are presented. Based on the concept of the impedance-based stability analysis, all damping methods can ensure the system stability by modifying the effective output impedance of the inverter or the effective grid impedance. Classical damping methods for industrial applications will be analyzed and compared. Finally, the future trends of the impedance-based stability analysis, as well as some promising damping methods, will be discussed. Autors: Weimin Wu;Yuan Liu;Yuanbin He;Henry Shu-Hung Chung;Marco Liserre;Frede Blaabjerg; Appeared in: IEEE Transactions on Industrial Electronics Publication date: Sep 2017, volume: 64, issue:9, pages: 7402 - 7413 Publisher: IEEE
» DASC: Robust Dense Descriptor for Multi-Modal and Multi-Spectral Correspondence Estimation
 Abstract:Establishing dense correspondences between multiple images is a fundamental task in many applications. However, finding a reliable correspondence between multi-modal or multi-spectral images still remains unsolved due to their challenging photometric and geometric variations. In this paper, we propose a novel dense descriptor, called dense adaptive self-correlation (DASC), to estimate dense multi-modal and multi-spectral correspondences. Based on an observation that self-similarity existing within images is robust to imaging modality variations, we define the descriptor with a series of an adaptive self-correlation similarity measure between patches sampled by a randomized receptive field pooling, in which a sampling pattern is obtained using a discriminative learning. The computational redundancy of dense descriptors is dramatically reduced by applying fast edge-aware filtering. Furthermore, in order to address geometric variations including scale and rotation, we propose a geometry-invariant DASC (GI-DASC) descriptor that effectively leverages the DASC through a superpixel-based representation. For a quantitative evaluation of the GI-DASC, we build a novel multi-modal benchmark as varying photometric and geometric conditions. Experimental results demonstrate the outstanding performance of the DASC and GI-DASC in many cases of dense multi-modal and multi-spectral correspondences. Autors: Seungryong Kim;Dongbo Min;Bumsub Ham;Minh N. Do;Kwanghoon Sohn; Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence Publication date: Sep 2017, volume: 39, issue:9, pages: 1712 - 1729 Publisher: IEEE
» Data Improving in Time Series Using ARX and ANN Models
 Abstract:Anomalous data can negatively impact energy forecasting by causing model parameters to be incorrectly estimated. This paper presents two approaches for the detection and imputation of anomalies in time series data. Autoregressive with exogenous inputs (ARX) and artificial neural network (ANN) models are used to extract the characteristics of time series. Anomalies are detected by performing hypothesis testing on the extrema of the residuals, and the anomalous data points are imputed using the ARX and ANN models. Because the anomalies affect the model coefficients, the data cleaning process is performed iteratively. The models are re-learned on “cleaner” data after an anomaly is imputed. The anomalous data are reimputed to each iteration using the updated ARX and ANN models. The ARX and ANN data cleaning models are evaluated on natural gas time series data. This paper demonstrates that the proposed approaches are able to identify and impute anomalous data points. Forecasting models learned on the unclean data and the cleaned data are tested on an uncleaned out-of-sample dataset. The forecasting model learned on the cleaned data outperforms the model learned on the unclean data with 1.67% improvement in the mean absolute percentage errors and a 32.8% improvement in the root mean squared error. Existing challenges include correctly identifying specific types of anomalies such as negative flows. Autors: Hermine N. Akouemo;Richard J. Povinelli; Appeared in: IEEE Transactions on Power Systems Publication date: Sep 2017, volume: 32, issue:5, pages: 3352 - 3359 Publisher: IEEE
» Data Reconstruction Using Subspace Analysis for Gas Classification
 Abstract:We propose a data reconstruction method using subspace analysis for gas classification in an electronic nose system. A noise generated by defects in sensors or by environmental factors in the process of data sampling significantly degrades data classification performance. In this paper, an electronic nose system more robust to data errors is designed by reconstructing lost or damaged values of data samples based on a statistical learning method that exploits the principal components. Diverse types of volatile organic compounds were employed in the classification experiments, which were conducted to reconstruct the lost or damaged data through the proposed method. The applied method prevented the degradation of classification performance and enhanced the discriminative power in the PCA+LDA feature space. Autors: Sang-Il Choi;Hong-Min Jeon;Gu-Min Jeong; Appeared in: IEEE Sensors Journal Publication date: Sep 2017, volume: 17, issue:18, pages: 5954 - 5962 Publisher: IEEE
» Data-Dependent Convergence for Consensus Stochastic Optimization
 Abstract:We study a distributed consensus-based stochastic gradient descent (SGD) algorithm and show that the rate of convergence involves the spectral properties of two matrices: The standard spectral gap of a weight matrix from the network topology and a new term depending on the spectral norm of the sample covariance matrix of the data. This data-dependent convergence rate shows that distributed SGD algorithms perform better on datasets with small spectral norm. Our analysis method also allows us to find data-dependent convergence rates as we limit the amount of communication. Spreading a fixed amount of data across more nodes slows convergence; for asymptotically growing datasets, we show that adding more machines can help when minimizing twice-differentiable losses. Autors: Avleen S. Bijral;Anand D. Sarwate;Nathan Srebro; Appeared in: IEEE Transactions on Automatic Control Publication date: Sep 2017, volume: 62, issue:9, pages: 4483 - 4498 Publisher: IEEE
» Data-Driven DG Capacity Assessment Method for Active Distribution Networks
 Abstract:This paper proposes a data-driven method based on distributionally robust optimization to determine the maximum penetration level of distributed generation (DG) for active distribution networks. In our method, the uncertain DG outputs and load demands are formulated as stochastic variables following some ambiguous distributions. In addition to the given expectations and variances, the polyhedral uncertainty intervals are employed for the construction of the probability distribution set to restrict possible distributions. Then, we decide the optimal sizes and locations of DG to maximize the total DG hosting capacity under the worst-case probability distributions among this set. Since more information is utilized, our proposed model is expected to be less conservative than the robust optimization method and the traditional distributionally robust method. Using the CVaR (Conditional Value at Risk) reformulation technique and strong duality, we transform the proposed model into an equivalent bilinear matrix inequality problem, and a sequential convex optimization algorithm is applied for solution. Our model guarantees that the probability of security constraints being violated will not exceed a given risk threshold. Besides, the predefined risk level can be tuned to control the conservativeness of our model in a physically meaningful way. The effectiveness and robustness of this proposed method are demonstrated numerically on the two modified IEEE test systems. Autors: Xin Chen;Wenchuan Wu;Boming Zhang;Chenhui Lin; Appeared in: IEEE Transactions on Power Systems Publication date: Sep 2017, volume: 32, issue:5, pages: 3946 - 3957 Publisher: IEEE
» Data-Driven Robust RVFLNs Modeling of a Blast Furnace Iron-Making Process Using Cauchy Distribution Weighted M-Estimation
 Abstract:Optimal operation of a practical blast furnace (BF) iron-making process depends largely on a good measurement of molten iron quality (MIQ) indices. However, measuring the MIQ online is not feasible using the available techniques. In this paper, a novel data-driven robust modeling is proposed for an online estimation of MIQ using improved random vector functional-link networks (RVFLNs). Since the output weights of traditional RVFLNs are obtained by the least squares approach, a robustness problem may occur when the training dataset is contaminated with outliers. This affects the modeling accuracy of RVFLNs. To solve this problem, a Cauchy distribution weighted M-estimation-based robust RFVLNs are proposed. Since the weights of different outlier data are properly determined by the Cauchy distribution, their corresponding contribution on modeling can be properly distinguished. Thus, robust and better modeling results can be achieved. Moreover, given that the BF is a complex nonlinear system with numerous coupling variables, the data-driven canonical correlation analysis is employed to identify the most influential components from multitudinous factors that affect the MIQ indices to reduce the model dimension. Finally, experiments using industrial data and comparative studies have demonstrated that the obtained model produces a better modeling and estimating accuracy and stronger robustness than other modeling methods. Autors: Ping Zhou;Youbin Lv;Hong Wang;Tianyou Chai; Appeared in: IEEE Transactions on Industrial Electronics Publication date: Sep 2017, volume: 64, issue:9, pages: 7141 - 7151 Publisher: IEEE
» Data-Driven Stochastic Transmission Expansion Planning
 Abstract:Due to the significant improvements of power generation technologies and the trend of replacing traditional power plants with renewable generation resources, the generation portfolio will experience dramatic changes in the near future. The uncertainty and variability of renewable energy and their sitting call for strategic and economic plans for expanding the transmission capacities. In this study, we develop a data-driven two-stage stochastic transmission expansion planning with uncertainties. In the proposed approach, purely by learning from the historical data, we first construct a confidence set for the unknown distribution of the uncertain parameters. Then, we develop a two-stage data-driven transmission expansion framework, by considering the worst-case distribution within the constructed confidence set, so as to provide a reliable while economic transmission planning decision. Furthermore, to tackle the model complexity, we propose a decomposition framework embedded with Benders’ and Column-and-Constraint generation methods. We implement our approach on 6-bus and 118-bus systems to test its effectiveness. Finally, we show as the amount of historical data grows, the conservativeness of the model decreases. Autors: Ali Bagheri;Jianhui Wang;Chaoyue Zhao; Appeared in: IEEE Transactions on Power Systems Publication date: Sep 2017, volume: 32, issue:5, pages: 3461 - 3470 Publisher: IEEE
» Day-Ahead Financial Loss/Gain Modeling and Prediction for a Generation Company
 Abstract:In an electricity market, the main goal of a generation company (GenCo) is to maximize its profit, while encountering the uncertainty of the electricity price forecast. Different risk measures have been proposed to cope with this source of uncertainty. However, those are usually before-the-fact performance indices and cannot give a measure for the financial loss/gain (FLG) of a GenCo considering the electricity prices actually realized in the market. This paper focuses on this matter. The time series of FLG is first constructed given the real conditions of the electricity market. Then, the FLG time series is quantized using Silhouette criterion and k-means clustering approach. Subsequently, based on the historical values of the quantized FLG time series and relevant exogenous variables, its day-ahead values are predicted. The method proposed for day-ahead FLG prediction consist of conditional mutual information and sequential forward search as the feature selection technique and extreme learning machine as the forecasting engine. The effectiveness of the whole proposed approach, including the FLG time series construction, quantization approach, and the prediction method, is shown for a typical GenCo using the real data of the PJM and Ontario electricity markets. Autors: Ali Doostmohammadi;Nima Amjady;Hamidreza Zareipour; Appeared in: IEEE Transactions on Power Systems Publication date: Sep 2017, volume: 32, issue:5, pages: 3360 - 3372 Publisher: IEEE
» DC 30-GHz DPDT Switch Matrix Design in High Resistivity Trap-Rich SOI
 Abstract:This paper presents low insertion loss, high isolation, ultra-wideband double-pole-double-throw (DPDT) switch matrix designed in a 0.13- commercial high resistivity trap-rich silicon-on-insulator (SOI) CMOS process for the first time. The switches are designed using series–shunt–series configuration in a ring-type structure with input and output matching networks. Transistor width and transistor channel length effects on the wideband DPDT switch performance are thoroughly investigated. The designed switches achieve widest bandwidth from dc to 30 GHz with a low insertion loss of 2.5 dB and a high isolation of 32 dB up to 30 GHz. The measured input P1dB of designed switches is higher than 18 dBm. It was found both second and third harmonics can be improved by widening switch transistor channel width, and third harmonic can be improved by shortening channel length. The active chip area of designed switch matrix is very small size of only 0.28 mm mm. Autors: Bo Yu;Kaixue Ma;Fanyi Meng;Kiat Seng Yeo;Parthasarathy Shyam;Shaoqiang Zhang;Purakh Raj Verma; Appeared in: IEEE Transactions on Electron Devices Publication date: Sep 2017, volume: 64, issue:9, pages: 3548 - 3554 Publisher: IEEE
» DC Bias Reversal Behavior of Spin–Torque Ferromagnetic Resonance Spectra in CoFeB/MgO/CoFeB Perpendicular Magnetic Tunnel Junction
 Abstract:Spin–torque ferromagnetic resonance (ST-FMR) spectra of nano-scaled CoFeB/MgO/CoFeB full perpendicular magnetic tunnel junctions (p-MTJs) were investigated, especially in detail at low dc-bias voltage region. Usually in in-plane magnetized MTJs (i-MTJs), the ST-FMR spectrum line shape reverses its symmetry as switching dc-bias voltage polarities; however, it is found that in the p-MTJs the line shape reversal behaves differently, that not only the spectrum shows anti-symmetric line shape at zero dc bias but also the dependence of reversal symmetry on dc bias is broken. Based on the framework of homodyne-detected ST-FMR, we extracted the parameters characterizing the spectra and discussed the possible factors resulting these differences. Autors: Tian Yu;Hiroshi Naganuma;Mikihiko Oogane;Yasuo Ando; Appeared in: IEEE Transactions on Magnetics Publication date: Sep 2017, volume: 53, issue:9, pages: 1 - 5 Publisher: IEEE
» Decoupled 2-D Direction of Arrival Estimation in L-Shaped Array
 Abstract:In this letter, we propose a novel decoupled method for 2-D direction of arrival (2-D DOA) estimation in L-shaped array. Specifically, in the proposed method, the Jacobi-Anger expansion is utilized to decouple the elevation angle from the azimuth angle, which means that the reconstructed manifold of the L-shaped array is the product of the two matrices of elevation and azimuth angles. Although the traditional 2-D MUSIC algorithm can estimate the elevation and azimuth angles without pair matching, it requires the complex 2-D spectrum peaks search. In order to simplify the searching procedure, the new formulation of the array manifold is applied in the Root-MUSIC algorithm, in which only 1-D elevation searching is needed to estimate the 2-D DOA and the azimuth estimates can be paired automatically with the elevation estimates. Simulation results are presented to confirm the effectiveness of the proposed method, and demonstrate that our proposed method achieves a better tradeoff between the performance and complexity than other existing methods. Autors: Zhi Zhang;Wenjie Wang;Yuzhen Huang;Shang Liu; Appeared in: IEEE Communications Letters Publication date: Sep 2017, volume: 21, issue:9, pages: 1989 - 1992 Publisher: IEEE
» Deep Boltzmann Regression With Mimic Features for Oscillometric Blood Pressure Estimation
 Abstract:Oscillometric blood pressure (BP) devices are among the standard automatic monitors, now readily available for the home, office, and hospital. The systolic blood pressure (SBP) and diastolic blood pressure (DBP) are obtained at fixed ratios of the envelope of the maximum amplitude of the oscillometric wave signal. However, these fixed ratios can cause overestimation or underestimation of the real SBP and DBP in oscillometric BP measurements. In this paper, we propose a new regression technique using a deep Boltzmann regression with mimic features based on the bootstrap technique to learn the complex nonlinear relationships between the mimic features vectors acquired from the oscillometric signals and the target BPs. The performance of the proposed model is compared with those of conventional and auscultatory techniques. Our regression model with mimic features provides lower standard deviation of error, mean error, mean absolute error, and standard error of estimates than the conventional techniques, along with a similar fit for the SBP and DBP. Autors: Soojeong Lee;Joon-Hyuk Chang; Appeared in: IEEE Sensors Journal Publication date: Sep 2017, volume: 17, issue:18, pages: 5982 - 5993 Publisher: IEEE
» Deep Learning-Based Large-Scale Automatic Satellite Crosswalk Classification
 Abstract:High-resolution satellite imagery has been increasingly used on remote sensing classification problems. One of the main factors is the availability of this kind of data. Despite the high availability, very little effort has been placed on the zebra crossing classification problem. In this letter, crowdsourcing systems are exploited in order to enable the automatic acquisition and annotation of a large-scale satellite imagery database for crosswalks related tasks. Then, this data set is used to train deep-learning-based models in order to accurately classify satellite images that contain or not contain zebra crossings. A novel data set with more than 240000 images from 3 continents, 9 countries, and more than 20 cities was used in the experiments. The experimental results showed that freely available crowdsourcing data can be used to accurately (97.11%) train robust models to perform crosswalk classification on a global scale. Autors: Rodrigo F. Berriel;André Teixeira Lopes;Alberto F. de Souza;Thiago Oliveira-Santos; Appeared in: IEEE Geoscience and Remote Sensing Letters Publication date: Sep 2017, volume: 14, issue:9, pages: 1513 - 1517 Publisher: IEEE
» Definition of Accurate Reference Synchrophasors for Static and Dynamic Characterization of PMUs
 Abstract:The calibration of phasor measurement units (PMUs) consists of comparing coordinated universal time time-aligned phasors (synchrophasors) measured by the PMU under test, against reference synchrophasors generated through a PMU calibrator. The IEEE Standard C37.118–2011 and its latest amendment (IEEE Std) describe compliance tests for static and dynamic conditions, and indicate the relative limits in terms of accuracy. In this context, this paper focuses on the definition and accuracy assessment of the reference synchrophasors in the test conditions defined by the above IEEE Std. In the first part of this paper, we describe the characterization of a nonlinear least-squares fitting algorithm used to determine the parameters of these reference synchrophasors. For this analysis, we deploy the proposed algorithm in a PMU calibrator and characterize the algorithm performance within the actual hardware implementation for both static and dynamic test conditions. More specifically, we generate reference waveforms through a highly stable high-resolution digital-to-analog converter and evaluate how the algorithm parameters (observation interval length and sampling frequency) affect the solution accuracy. In the second part, we discuss on the appropriateness of the synchrophasor model in the evaluation of PMU performance under step test conditions. In this regard, we propose an alternative time-domain approach to assess the synchrophasor estimate during transient events. Autors: Guglielmo Frigo;Daniele Colangelo;Asja Derviškadić;Marco Pignati;Claudio Narduzzi;Mario Paolone; Appeared in: IEEE Transactions on Instrumentation and Measurement Publication date: Sep 2017, volume: 66, issue:9, pages: 2233 - 2246 Publisher: IEEE
» Degrees of Freedom of the Two-User MIMO Broadcast Channel With Private and Common Messages Under Hybrid CSIT Models
 Abstract:We establish the degree of freedom (DoF) regions of the two-user multiple-input multiple-output (MIMO) broadcast channel with a general message set (BC-GM), that includes private and common messages, under fast fading. Nine different channel state knowledge assumptions—collectively known as hybrid channel state information at the transmitter (CSIT) models—are considered wherein the transmitter has either perfect/instantaneous, delayed, or no CSI from each of the two receivers. General antenna configurations are addressed wherein the three terminals have arbitrary numbers of antennas. The DoF regions are established for the five hybrid CSIT models in which either both channels are unknown at the transmitter or each of the two channels is known perfectly or with delay. In the four remaining cases in which exactly one of the two channels is unknown at the transmitter, the DoF regions under the restriction of linear encoding strategies—also known as the linear DoF (LDoF) regions—are established. As the key to the converse proofs of the LDoF region of the MIMO BC-GM under such hybrid CSIT assumptions, we show that, when only considering linear encoding strategies, the CSI from the receiver with more antennas does not help if there is no CSI available from the receiver with fewer antennas. This result is conjectured to be true even without the restriction on the encoding strategies to be linear. If true, the LDoF regions obtained for the four hybrid CSIT cases herein will also be the DoF regions for those cases. Many of the results of this paper when specialized to even the two-message problems are new. These include the LDoF regions, when one of the two channels is not known, of the MIMO BC-GM when specialized to the MIMO BC with private messages. They also include the DoF/LDoF regions for all the hybrid CSIT models obtained by specializing the corresponding regions for the MIMO BC-GM to the cas- with degraded messages. Autors: Yao Wang;Mahesh K. Varanasi; Appeared in: IEEE Transactions on Information Theory Publication date: Sep 2017, volume: 63, issue:9, pages: 6004 - 6019 Publisher: IEEE
» Demonstration and evaluation of an optimized RFS comb for terabit flexible optical networks
 Abstract:We experimentally demonstrate and evaluate an optimization strategy of a recirculating frequency shifting (RFS) optical comb for terabit flexible optical networks. We achieve an increased optical signal-to-noise ratio (OSNR) with good stability (no system outage) by reducing erbium-doped-fiber amplifier gain in the shifting loop and deploying an in-loop noise suppression filter. We demonstrate that this source can support 20 × 200 Gb/s dual polarization Nyquist-16QAM transmission. With optimization, the RFS comb has greater and more uniform OSNR per channel. Flexible optical networks with software-defined networking are particularly suited to this enhanced RFS due to 1) programmable frequency spacing, 2) dense, stable spacing enabling very high spectral efficiency, 3) uniform performance across channels, and 4) sufficient OSNR for high-order modulation. The RFS can be used in short links when using low overhead forward error correction (FEC). Distances as great as 1150 km are achieved when using a 20% FEC overhead. Long-distance tests at 4 Tb/s result in a post-FEC net rate of 3.3 Tb/s and 6.3 bit/s/Hz of spectral efficiency. Autors: Jiachuan Lin;Lixian Wang;Mingyang Lyu;Amruta Pai;Xiaoguang Zhang;Sophie LaRochelle;Leslie A. Rusch; Appeared in: IEEE/OSA Journal of Optical Communications and Networking Publication date: Sep 2017, volume: 9, issue:9, pages: 739 - 746 Publisher: IEEE
» Demonstration of AlN Schottky Barrier Diodes With Blocking Voltage Over 1 kV
 Abstract:This letter reports the first demonstration of 1-kV-class AlN Schottky barrier diodes on sapphire substrates by metal organic chemical vapor deposition. The device structure mimics the silicon-on-insulator (SOI) technology, consisting of thin -AlN epilayer as the device active region and thick resistive AlN underlayer as the insulator. At room temperature, the devices show outstanding performances with a low turn-ON voltage of 1.2 V, a high ON/OFF ratio of , a low ideality factor of 5.5, and a low reverse leakage current below 1 nA. The devices also exhibit excellent thermal stability over 500 K owing to the ultra-wide bandgap of AlN. The breakdown voltage of the devices can be further improved by employing field plate, edge termination technologies, and optimizing the SOI-like device structure. This letter presents a cost-effective route to high performance AlN-based Schottky barrier diodes for high-power, high-voltage, and high-temperature applications. Autors: Houqiang Fu;Izak Baranowski;Xuanqi Huang;Hong Chen;Zhijian Lu;Jossue Montes;Xiaodong Zhang;Yuji Zhao; Appeared in: IEEE Electron Device Letters Publication date: Sep 2017, volume: 38, issue:9, pages: 1286 - 1289 Publisher: IEEE
» Demonstration of multi-domain spectrum defragmentation with minimum controller-participation degree in elastic optical networks
 Abstract:Spectrum fragmentation is a critical issue in elastic optical networks, which leads to inefficient spectrum utilization and high blocking probability. Spectrum defragmentation is considered to conduct reconfiguration of the deployed lightpaths according to different optimization strategies. Compared with the single-domain scenario, spectrum defragmentation in the multi-domain becomes much more complex and challenging due to the necessity of multi-domain cooperation. Based on the hierarchical control architecture of software-defined networking (SDN), this paper proposes a multi-domain defragmentation (MD-DF) scheme with minimum controller-participation degree (CPD). The concept of CPD is introduced to quantize the times that local controllers are involved in multi-domain defragmentation. Based on whether the potential blocked lightpath goes through inter-domain links, the MD-DF scheme includes intra-domain DF and inter-domain DF. The proposed scheme is implemented in the SDN control plane, and experimental results validate its overall feasibility. Meanwhile, the performance of the proposed scheme is evaluated in simulation with three different ratios of intradomain lightpaths. Simulation results indicate that the MD-DF scheme can optimize the utilization of the spectrum resource and achieve a better blocking probability. In addition, this paper also compares intra-domain DF with interdomain DF in terms of operation latency and execution times. Autors: Yajie Li;Yongli Zhao;Jie Zhang;Xiaosong Yu;Haoran Chen;Guoying Zhang; Appeared in: IEEE/OSA Journal of Optical Communications and Networking Publication date: Sep 2017, volume: 9, issue:9, pages: 782 - 791 Publisher: IEEE
» Denoising of Hyperspectral Images Using Nonconvex Low Rank Matrix Approximation
 Abstract:Hyperspectral image (HSI) denoising is challenging not only because of the difficulty in preserving both spectral and spatial structures simultaneously, but also due to the requirement of removing various noises, which are often mixed together. In this paper, we present a nonconvex low rank matrix approximation (NonLRMA) model and the corresponding HSI denoising method by reformulating the approximation problem using nonconvex regularizer instead of the traditional nuclear norm, resulting in a tighter approximation of the original sparsity-regularised rank function. NonLRMA aims to decompose the degraded HSI, represented in the form of a matrix, into a low rank component and a sparse term with a more robust and less biased formulation. In addition, we develop an iterative algorithm based on the augmented Lagrangian multipliers method and derive the closed-form solution of the resulting subproblems benefiting from the special property of the nonconvex surrogate function. We prove that our iterative optimization converges easily. Extensive experiments on both simulated and real HSIs indicate that our approach can not only suppress noise in both severely and slightly noised bands but also preserve large-scale image structures and small-scale details well. Comparisons against state-of-the-art LRMA-based HSI denoising approaches show our superior performance. Autors: Yongyong Chen;Yanwen Guo;Yongli Wang;Dong Wang;Chong Peng;Guoping He; Appeared in: IEEE Transactions on Geoscience and Remote Sensing Publication date: Sep 2017, volume: 55, issue:9, pages: 5366 - 5380 Publisher: IEEE
» Dense Multipath Component Characteristics in 11-GHz-Band Indoor Environments
 Abstract:In the next-generation mobile communication system, the higher frequency bands from C-band to V-band are expected to be utilized because it has the potential to improve network capacity drastically by the available wideband spectrum. Since the characteristics of reflected and scattered radio waves from surrounding environments in those bands are thought to be quite different than at lower frequencies, the clarification of its influence on the multiple-input multiple-output (MIMO) transmission performance is a critical issue. In this paper, we focused on the characteristics of diffuse scattering in X-band, and conducted the MIMO channel measurements in indoor environments in the 11-GHz band. The frequency, angular, and polarization domain dense multipath component (DMC) propagation parameters were jointly estimated by using the RiMAX-based estimator. The measurement result showed the existence of significant DMC, which is thought to have originated from the floor, the ceiling as well as the walls. The angular spreads of the DMC tended to increase, and their decay factor tended to decrease as the room size decreased. It is also shown that the existence of DMC significantly affected the eigenvalue structure of the MIMO channel, which defines the MIMO transmission performance. The result is expected to be utilized for novel MIMO channel modeling in X-band that includes the DMC contribution. Autors: Kentaro Saito;Jun-Ichi Takada;Minseok Kim; Appeared in: IEEE Transactions on Antennas and Propagation Publication date: Sep 2017, volume: 65, issue:9, pages: 4780 - 4789 Publisher: IEEE
» Dense Semantic 3D Reconstruction
 Abstract:Both image segmentation and dense 3D modeling from images represent an intrinsically ill-posed problem. Strong regularizers are therefore required to constrain the solutions from being ‘too noisy’. These priors generally yield overly smooth reconstructions and/or segmentations in certain regions while they fail to constrain the solution sufficiently in other areas. In this paper, we argue that image segmentation and dense 3D reconstruction contribute valuable information to each other’s task. As a consequence, we propose a mathematical framework to formulate and solve a joint segmentation and dense reconstruction problem. On the one hand knowing about the semantic class of the geometry provides information about the likelihood of the surface direction. On the other hand the surface direction provides information about the likelihood of the semantic class. Experimental results on several data sets highlight the advantages of our joint formulation. We show how weakly observed surfaces are reconstructed more faithfully compared to a geometry only reconstruction. Thanks to the volumetric nature of our formulation we also infer surfaces which cannot be directly observed for example the surface between the ground and a building. Finally, our method returns a semantic segmentation which is consistent across the whole dataset. Autors: Christian Häne;Christopher Zach;Andrea Cohen;Marc Pollefeys; Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence Publication date: Sep 2017, volume: 39, issue:9, pages: 1730 - 1743 Publisher: IEEE
» Dermoscopic Image Segmentation via Multistage Fully Convolutional Networks
 Abstract:Objective: Segmentation of skin lesions is an important step in the automated computer aided diagnosis of melanoma. However, existing segmentation methods have a tendency to over- or under-segment the lesions and perform poorly when the lesions have fuzzy boundaries, low contrast with the background, inhomogeneous textures, or contain artifacts. Furthermore, the performance of these methods are heavily reliant on the appropriate tuning of a large number of parameters as well as the use of effective preprocessing techniques, such as illumination correction and hair removal. Methods: We propose to leverage fully convolutional networks (FCNs) to automatically segment the skin lesions. FCNs are a neural network architecture that achieves object detection by hierarchically combining low-level appearance information with high-level semantic information. We address the issue of FCN producing coarse segmentation boundaries for challenging skin lesions (e.g., those with fuzzy boundaries and/or low difference in the textures between the foreground and the background) through a multistage segmentation approach in which multiple FCNs learn complementary visual characteristics of different skin lesions; early stage FCNs learn coarse appearance and localization information while late-stage FCNs learn the subtle characteristics of the lesion boundaries. We also introduce a new parallel integration method to combine the complementary information derived from individual segmentation stages to achieve a final segmentation result that has accurate localization and well-defined lesion boundaries, even for the most challenging skin lesions. Results: We achieved an average Dice coefficient of 91.18% on the ISBI 2016 Skin Lesion Challenge dataset and 90.66% on the PH2 dataset. Conclusion and Significance: Our extensive experimental results on two well-established public b- nchmark datasets demonstrate that our method is more effective than other state-of-the-art methods for skin lesion segmentation. Autors: Lei Bi;Jinman Kim;Euijoon Ahn;Ashnil Kumar;Michael Fulham;Dagan Feng; Appeared in: IEEE Transactions on Biomedical Engineering Publication date: Sep 2017, volume: 64, issue:9, pages: 2065 - 2074 Publisher: IEEE
» Design and Analysis of an Always-ON Input-Biased pA-Current Sub-nW mV-Threshold Hysteretic Comparator for Near-Zero Energy Sensing
 Abstract:This paper presents the design and analysis of an always-ON comparator capable of detecting mV-range input voltage signals reliably with sub-nW power consumption. The comparator compares the two pA currents generated by current mirrors biased by the mV-range input signal. With the input signal near zero at the standby mode, the comparator consumes near-zero energy. A positive feedback is introduced to accelerate the output signal transition to the supply or the ground and to generate the hysteresis to tolerate the noise in the input signal. The comparator threshold and the amount of hysteresis are programmed using control signals to adjust the current mirror transistor sizes. Analytic expressions of comparator characteristics are derived using circuit theory and subthreshold transistor models, and have been validated using simulation and measurement. A prototype comparator implementing these ideas was designed and fabricated in a standard 65-nm CMOS process. Chip measurements have shown that the comparator achieved programmable thresholds from 27 to 46.5 mV with energy per switching from 1.9 to 2.4 nJ using four control bits. The measured power consumption is 270 pW at the input signal of 0.1 mV with the frequency of 10 Hz. Autors: Aili Wang;Chixiao Chen;Chuanjin Richard Shi; Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers Publication date: Sep 2017, volume: 64, issue:9, pages: 2284 - 2294 Publisher: IEEE
» Design and Evaluation of a Data-Driven Scenario Generation Framework for Game-Based Training
 Abstract:Generating suitable game scenarios that can cater for individual players has become an emerging challenge in procedural content generation. In this paper, we propose a data-driven scenario generation framework for game-based training. An evolutionary scenario generation process is designed with a fitness evaluation methodology that integrates the processes of AI player modeling, simulation and model training based on artificial neural networks. The fitness function for scenario evaluation can be automatically constructed based on the proposed methodology. To further enhance the evaluation of scenarios, we specifically study the impact of the timing of events in a scenario and propose a generic scenario representation model that characterizes individual scenario based on the types and timing of events in the scenario. We present an extensive evaluation of our framework by validating our AI player model, demonstrating the impact of timing of events in a scenario and comparing the effectiveness of our data-driven framework with our previous heuristic-based approach and a random baseline. The results show that it is necessary to consider the timing of events for scenario evaluation and the proposed framework works well in generating scenarios for game-based training. Autors: Linbo Luo;Haiyan Yin;Wentong Cai;Jinghui Zhong;Michael Lees; Appeared in: IEEE Transactions on Computational Intelligence and AI in Games Publication date: Sep 2017, volume: 9, issue:3, pages: 213 - 226 Publisher: IEEE
» Design and Experimental Demonstration of a Compact Silicon Photonic Interleaver Based on an Interfering Loop With Wide Spectral Range
 Abstract:We present the design and experimental demonstration of a compact tunable silicon photonic interleaver with a wide spectral range. The interleaver consists of an interfering loop containing a Fabry-Perot cavity formed by two Sagnac loops. The transmission coefficients of the directional couplers are calculated based on the maximally flat criterion. The impacts of the transmission coefficient variations on the extinction ratio and filter sharpness are investigated. The wavelength dependences of the directional couplers are analyzed to increase the spectral range of the interleaver. The device was fabricated on a silicon-on-insulator platform. The spectral ranges of the measured transmission and reflection spectra are increased to 60 nm. By thermal tuning the waveguide connecting the two Sagnac loops, the central wavelength can be shifted over one free spectral range with a wavelength-tuning efficiency of ~0.08 nm/mW. Autors: Xinhong Jiang;Yuxing Yang;Hongxia Zhang;Jizong Peng;Yong Zhang;Ciyuan Qiu;Yikai Su; Appeared in: Journal of Lightwave Technology Publication date: Sep 2017, volume: 35, issue:17, pages: 3765 - 3771 Publisher: IEEE
» Design and Implementation of an Optical Receiver for Angle-of-Arrival-Based Positioning
 Abstract:Optical wireless (OW) technology has attracted significant interest for indoor positioning in the past decade. An emerging form of this technology makes use of angle-of-arrival (AOA) measurements to carry out positioning via triangulation off of an optical beacon grid. Such AOA-based OW positioning systems can yield accurate position estimates—but only given sufficient attention to the optical receiver. The design, operation, and implementation of such a receiver are presented in this work. The optical receiver is designed to have a sufficiently small AOA error, being σAOA = 1°, over a wide angular field-of-view (FOV), being 100°. The design allows the optical receiver to carry out positioning based off a 3 × 3 grid of optical beacons, where each optical beacon is uniquely identified using multiple frequency and color channels. The optical beacons are widely spaced to fully utilize the optical receiver's wide angular FOV. The overall AOA-based OW positioning system exhibits a position error of 1.7 cm, which is comparable to those obtained by more complex positioning systems. Thus, the presented AOA-based technologies can play a role in emerging indoor positioning systems. Autors: Mark H. Bergen;Xian Jin;Daniel Guerrero;Hugo A. L. F. Chaves;Naomi V. Fredeen;Jonathan F. Holzman; Appeared in: Journal of Lightwave Technology Publication date: Sep 2017, volume: 35, issue:18, pages: 3877 - 3885 Publisher: IEEE
» Design and Psychophysical Evaluation of the HapSticks: A Novel Non-Grounded Mechanism for Presenting Tool-Mediated Vertical Forces
 Abstract:Force feedback in tool-mediated interactions with the environment is important for the successful performance of complex tasks in daily life as well as in specialized fields such as medicine. Most stylus-based haptic devices require either grounding or attachment to the user’s body. Recently, non-grounded haptic devices have attracted a growing interest. In this study, we propose a non-grounded rotation mechanism to represent the vertical forces applied on the tip of a tool by mimicking the cutaneous sensations that are caused by such forces. As an example of an application of our method, we developed a non-grounded haptic device called HapSticks, which mimicked the sensation of manipulating objects using chopsticks. First, using an adjustment paradigm, we directly compared a virtual weight rendered by our device and a real weight to investigate the relation of real weight and virtual weight. Next, we used a forced choice constant stimuli paradigm in a virtual and a real weight discrimination task. We conclude that our novel device renders a reliable illusion of sensed weight that leads to a discrimination ability that is typical of virtual-reality applications but worse than the discrimination between real weights. Autors: Ginga Kato;Yoshihiro Kuroda;Ilana Nisky;Kiyoshi Kiyokawa;Haruo Takemura; Appeared in: IEEE Transactions on Haptics Publication date: Sep 2017, volume: 10, issue:3, pages: 338 - 349 Publisher: IEEE
» Design and Simulation of a Novel Graded-Channel Heterojunction Tunnel FET With High ${I} _{\scriptscriptstyle\text {ON}}/{I} _{\scriptscriptstyle\text {OFF}}$ Ratio and Steep Swing
 Abstract:In this letter, a novel graded-channel heterojunction tunnel field-effect transistor (GCH-TFET) is proposed and studied by simulation. The novel TFET adopts a near broken-gap heterojunction at the source/channel interface to enhance the tunnel efficiency. Besides, it employs a graded component channel which works as an electron barrier to block up the leakage current at the OFF-state and can be removed with the increased gate voltage at the ON-state for high ON/ OFF-current () ratio. Such graded channel also allows a sudden turn-on of band-to-band tunneling, resulting in a reduced sub-threshold swing (SS) compared with conventional heterojunction TFETs. The GCH-TFET demonstrates an ratio of more than seven decades with up to 225 at V, more than two decades lower than a near broken-gap heterojunction TFET and SS lower than 30 mV/decade for more than five decades, exhibiting excellent potential for ultra-low power applications. Autors: Jiadi Zhu;Yang Zhao;Qianqian Huang;Cheng Chen;Chunlei Wu;Rundong Jia;Ru Huang; Appeared in: IEEE Electron Device Letters Publication date: Sep 2017, volume: 38, issue:9, pages: 1200 - 1203 Publisher: IEEE
» Design Automation of Cyber-Physical Systems: Challenges, Advances, and Opportunities
 Abstract:A cyber-physical system (CPS) is an integration of computation with physical processes whose behavior is defined by both computational and physical parts of the system. In this paper, we present a view of the challenges and opportunities for design automation of CPS. We identify a combination of characteristics that define the challenges unique to the design automation of CPS. We then present selected promising advances in depth, focusing on four foundational directions: combining model-based and data-driven design methods; design for human-in-the-loop systems; component-based design with contracts, and design for security and privacy. These directions are illustrated with examples from two application domains: smart energy systems and next-generation automotive systems. Autors: Sanjit A. Seshia;Shiyan Hu;Wenchao Li;Qi Zhu; Appeared in: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems Publication date: Sep 2017, volume: 36, issue:9, pages: 1421 - 1434 Publisher: IEEE

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