Electrical and Electronics Engineering publications abstract of: 09-2017 sorted by title, page: 4

» Automatic MTPA Tracking in IPMSM Drives: Loop Dynamics, Design, and Auto-Tuning
Abstract:
Maximum Torque Per Ampere (MTPA) based on motor parameters is a common approach to achieve high efficiency and torque density in Interior Permanent Magnet Synchronous Machine Drives (IPMSMs). However, uncertainty (e.g., due to identification errors, magnetic saturation, or temperature variation) results in undesired deviation from the optimal operating trajectory. To solve this problem, MTPA tracking methods have been proposed, which exploit signal injection to search the minimum current point for a certain load torque in a closed-loop fashion. Closed-form design of the MTPA tracking loop dynamics has never been addressed in past literature and represents the main topic of this paper. A recent and efficient tracking method has been considered for the analysis and case study, i.e., [14]. Nonlinear small-signal gain of the loop can be calculated in closed form, leading to two valuable results. Dynamics can be programmed by optimal design of the tracking regulator, and online adaptation can be applied, making the designed MTPA tracking dynamics invariant with the operating point. A straightforward and effective solution is proposed for the regulator design, which allows us to obtain the desired bandwidth and first-order tracking response in the whole range of operation, being also suitable for auto-tuning and online adaptation. The method has been studied analytically and in simulation, also considering the influence of noise and parametric uncertainties. Finally the technique has been implemented on the hardware of a commercial industrial drive, proving the effectiveness of the proposal. The concepts described in this paper, design approach and adaptation strategy, analyzed here for the first time, are general and can be applied to any control scheme implementing closed-loop MTPA tracking.
Autors: Nicola Bedetti;Sandro Calligaro;Christian Olsen;Roberto Petrella;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Sep 2017, volume: 53, issue:5, pages: 4547 - 4558
Publisher: IEEE
 
» Automatic Skin Lesion Segmentation Using Deep Fully Convolutional Networks With Jaccard Distance
Abstract:
Automatic skin lesion segmentation in dermoscopic images is a challenging task due to the low contrast between lesion and the surrounding skin, the irregular and fuzzy lesion borders, the existence of various artifacts, and various imaging acquisition conditions. In this paper, we present a fully automatic method for skin lesion segmentation by leveraging 19-layer deep convolutional neural networks that is trained end-to-end and does not rely on prior knowledge of the data. We propose a set of strategies to ensure effective and efficient learning with limited training data. Furthermore, we design a novel loss function based on Jaccard distance to eliminate the need of sample re-weighting, a typical procedure when using cross entropy as the loss function for image segmentation due to the strong imbalance between the number of foreground and background pixels. We evaluated the effectiveness, efficiency, as well as the generalization capability of the proposed framework on two publicly available databases. One is from ISBI 2016 skin lesion analysis towards melanoma detection challenge, and the other is the PH2 database. Experimental results showed that the proposed method outperformed other state-of-the-art algorithms on these two databases. Our method is general enough and only needs minimum pre- and post-processing, which allows its adoption in a variety of medical image segmentation tasks.
Autors: Yading Yuan;Ming Chao;Yeh-Chi Lo;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Sep 2017, volume: 36, issue:9, pages: 1876 - 1886
Publisher: IEEE
 
» Automatic Welding Seam Tracking and Identification
Abstract:
In the automatic welding process on mid/thick plates, the precision of the welding position has an important effect on welding quality, which mainly relies on the identification of the welding seam. However, due to some possible disturbances in complex unstructured welding environments, e.g., strong arc lights, welding splashes, thermal-induced deformations, etc., it is a great challenge to identify the welding seam. In this paper, we propose a robust automatic welding seam identification and tracking method by utilizing structured-light vision. First, after the preprocessing of the welding image, the gray distribution of the laser stripe is tracked and the profile of the welding seam is searched in a small area by using the Kalman filter, with the aim to avoid some disturbances. Second, in order to extract the welding seam profile, a series of centroids obtained by scanning the columns in the rectangular window are fitted using the least-squares method. Third, a character string method is proposed to qualitatively describe the welding seam profile, which might consist of different segment and junction relationship elements. And then, these character strings acquired from the object image are matched with those from the model, so that the position of the welding seam can be determined. Finally, the advantages of the new algorithm are testified and compared through several experiments.
Autors: Xinde Li;Xianghui Li;Shuzhi Sam Ge;Mohammad Omar Khyam;Chaomin Luo;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Sep 2017, volume: 64, issue:9, pages: 7261 - 7271
Publisher: IEEE
 
» Autonomous Relay for Millimeter-Wave Wireless Communications
Abstract:
Millimeter-wave (mmWave) communication is the rising technology for next-generation wireless transmission. Benefited by its abundant bandwidth and short wavelength, mmWave is advanced in multi-gigabit transmittability and beamforming. In contrast, the short wavelength also makes mmWave easily blocked by obstacles. In order to bypass these obstacles, relays are widely needed in mmWave communications. Unmanned autonomous vehicles (UAVs), such as drones and self-driving robots, enable the mobile relays in real applications. Nevertheless, it is challenging for a UAV to find its optimal relay location automatically. On the one hand, it is difficult to find the location accurately due to the complex and dynamic wireless environment; on the other hand, most applications require the relay to forward data immediately, so the autonomous process should be fast. To tackle this challenge, we propose a novel method AutoRelay specialized for mmWave communications. In AutoRelay, the UAV samples the link qualities of mmWave beams while moving. Based on the real-time sampling, the UAV gradually adjusts its path to approach the optimal location by leveraging compressive sensing theory to estimate the link qualities in candidate space, which increases the accuracy and save the time. Performance results demonstrate that AutoRelay outperforms existing methods in achieving an accurate and efficient relay strategy.
Autors: Linghe Kong;Linsheng Ye;Fan Wu;Meixia Tao;Guihai Chen;Athanasios V. Vasilakos;
Appeared in: IEEE Journal on Selected Areas in Communications
Publication date: Sep 2017, volume: 35, issue:9, pages: 2127 - 2136
Publisher: IEEE
 
» Autonomous Surveillance Robots: A Decision-Making Framework for Networked Muiltiagent Systems
Abstract:
This article proposes an architecture for an intelligent surveillance system, where the aim is to mitigate the burden on humans in conventional surveillance systems by incorporating intelligent interfaces, computer vision, and autonomous mobile robots. Central to the intelligent surveillance system is the application of research into planning and decision making in this novel context. In this article, we describe the robot surveillance decision problem and explain how the integration of components in our system supports fully automated decision making. Several concrete scenarios deployed in real surveillance environments exemplify both the flexibility of our system to experiment with different representations and algorithms and the portability of our system into a variety of problem contexts. Moreover, these scenarios demonstrate how planning enables robots to effectively balance surveillance objectives, autonomously performing the job of human patrols and responders.
Autors: Stefan Witwicki;Jose Carlos Castillo;Joao Messias;Jesus Capitan;Francisco S. Melo;Pedro U. Lima;Manuela Veloso;
Appeared in: IEEE Robotics & Automation Magazine
Publication date: Sep 2017, volume: 24, issue:3, pages: 52 - 64
Publisher: IEEE
 
» Autonomous Switched Control of Load Shifting Robot Manipulators
Abstract:
An autonomous switched controller is proposed for a robot manipulator to ensure asymptotical tracking performance in the presence of shifting loads. Since the manipulator parameter jumps along with the load shift, the manipulator is modeled as a switched system whose switching signal depicts the load change. When the load change is not detectable, the switching signal of the switched system is unavailable. In this case, another “autonomous” switching law is designed for the given subcontrollers using a switched reset supervisory variable. Asymptotic tracking is ensured for slow load shifting. The effectiveness of the proposed method is verified by both simulations of a 2-DOF robot manipulator and experiments of a closed-chain five-bar robot.
Autors: Xia Wang;Jun Zhao;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Sep 2017, volume: 64, issue:9, pages: 7161 - 7170
Publisher: IEEE
 
» Backward-Wave Oscillator Operating in Low Magnetic Fields Using a Hybrid-TE11 Mode
Abstract:
We present the design of a backward-wave oscillator based on a novel slow-wave structure (SWS) operating under low magnetic field conditions (<0.2 T). The design features a high-power electron beam interacting in dual synchronism with TM01 and hybrid TE11 modes. By exploiting mode control techniques, low magnetic fields with asymmetrical beam trajectories, a dominant interaction with the higher frequency hybrid TE11 mode is established. We present a design of the full interaction circuit, which also features a compact mode converter and an output coupler to produce a TE01 mode at the dual rectangular waveguide output. Simulations with a high-frequency structural simulator demonstrate dual-mode backward wave synchronism. A quantitative analysis of the electric field profiles is also presented. We also use a particle-in-cell (PIC) solver to predict the SWS performance under hot-test facility specific conditions. Using a 490-kV, 84-A electron beam under a guiding magnetic field of 0.15 T, PIC simulations predict an output power of 18 MW at 5 GHz with a peak power efficiency of 44%.
Autors: Ushemadzoro Chipengo;Niru K. Nahar;John L. Volakis;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Sep 2017, volume: 64, issue:9, pages: 3863 - 3869
Publisher: IEEE
 
» Balanced Mixture of Deformable Part Models With Automatic Part Configurations
Abstract:
This paper presents a method to improve the traditional mixture of deformable part models (MDPM) method from the learning perspective. First, an object part configuration learning algorithm based on group sparsity constraint is introduced to automatically discover the object part number, size, and location. The algorithm imposes two additional regularization terms in addition to the standard hinge loss function. The first term focuses on automatic part selection and the second term focuses on automatic part placement. Second, this paper introduces an improved MDPM training framework. The framework applies a learned transformation to normalize the prediction score from each individual deformable part model (DPM) into a pseudo probability such that the partition of the entire object appearance feature space becomes less sensitive to the prior distributions of different DPMs. Finally, the two proposed improvements are combined and formulated under the expectation-maximization framework. We evaluate our method mainly using the PASCAL VOC2007 and VOC2010 detection benchmarks and show that the proposed learning algorithms could increase the detection mean AP score by 2.4% and 0.9%, respectively, on these two data sets when using the proposed part selection method and the training algorithm. We also present further in-depth analysis of the proposed algorithm in the experiments.
Autors: De Cheng;Yihong Gong;Jingjun Wang;Nanning Zheng;
Appeared in: IEEE Transactions on Circuits and Systems for Video Technology
Publication date: Sep 2017, volume: 27, issue:9, pages: 1962 - 1973
Publisher: IEEE
 
» Balancing Buffer-Aided Relay Selection for Cooperative Relaying Systems
Abstract:
In this paper, we propose a relay selection scheme for buffer-aided cooperative relay networks. The proposed scheme exploits the channel state information and the buffer state information to minimize the outage probability. To achieve that, it constantly seeks to maintain the states of the buffers by balancing the arrival and departure rates at each relay's buffer. More specifically, the half-full buffer state is used as a reference to monitor the state of balance, where a relay's buffer is considered balanced if its arrival and departure rates are equal. In each time slot, among all links that are available for selection, the one that can enhance the balance status of the most unbalanced buffer is selected. The outage probability performances in independent and identically distributed and independent and nonidentically distributed Rayleigh fading channels are investigated. In terms of outage probability, simulation results show that the proposed scheme significantly outperforms the max-link scheme and achieves some improvement compared to the buffer-state-based scheme.
Autors: Ali Ahmed Mohamed Siddig;Mohd Fadzli Mohd Salleh;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Sep 2017, volume: 66, issue:9, pages: 8276 - 8290
Publisher: IEEE
 
» Balancing Energy Efficiency and Device Lifetime in TWDM-PON Under Traffic Fluctuations
Abstract:
Energy-efficient time- and wavelength-division multiplexed passive optical network has been intensely investigated. However, conventional schemes aimed at energy efficiency may bring about repeated power-state transitions between sleep mode and active mode, resulting in periodic device-temperature cycling and frequent wavelength reassignment, which will greatly deteriorate network quality of service. These side effects become non-trivial when traffic fluctuates sharply as expected in the future. In this letter, we propose a wavelength-postponed-switching-off (WPS) strategy to reduce power-state transitions by means of postponing the power-off of redundant wavelengths. Redundant wavelengths represent wavelengths that are supposed to be powered off by conventional schemes when traffic declines. Illustrative results show that, the WPS strategy can provide a balanced performance of both energy efficiency and device lifetime, while decreasing service interruption caused by turning ON or OFF the equipment.
Autors: Jialong Li;Zhizhen Zhong;Nan Hua;Xiaoping Zheng;Bingkun Zhou;
Appeared in: IEEE Communications Letters
Publication date: Sep 2017, volume: 21, issue:9, pages: 1981 - 1984
Publisher: IEEE
 
» Band Offset Enhancement of a-Al2O3/Tensile-Ge for High Mobility Nanoscale pMOS Devices
Abstract:
The band alignment properties of amorphous Al2O3 on strain-engineered biaxial tensile-strained epitaxial Ge, grown in situ by molecular beam epitaxy on InxGa1–xAs virtual substrates, are presented. X-ray photoelectron spectroscopy investigation demonstrated an increase in the valence band offset of the Al2O3/strained Ge system with increasing tensile strain. For Ge strain-states of 1.14%, 1.6%, and 1.94%, the corresponding valence band offsets were found to be 4.43 ± 0.1 eV, 3.95 ± 0.1 eV, and 4.55 ± 0.1 eV, respectively, demonstrating a ~0.8 eV increase as compared with Ge grown on GaAs. The observed enhancement in the valence band discontinuity between tensile-strained Ge and Al2O3 offers a unique and novel path for the simultaneous improvement of hole mobility (via strain) and hole confinement (via a larger valence band offset) in future low-power and high-performance Ge-based nanoscale pMOS devices.
Autors: Michael B. Clavel;Mantu K. Hudait;
Appeared in: IEEE Electron Device Letters
Publication date: Sep 2017, volume: 38, issue:9, pages: 1196 - 1199
Publisher: IEEE
 
» Band Subset Selection for Anomaly Detection in Hyperspectral Imagery
Abstract:
This paper presents a new approach, called band subset selection (BSS)-based hyperspectral anomaly detection (AD), which selects multiple bands simultaneously as a band subset rather than selecting multiple bands one at a time as the tradition band selection (BS) does, referred to as sequential multiple BS (SQMBS). Its idea is to first use virtual dimensionality (VD) to determine the number of multiple bands, needed to be selected as a band subset and then develop two iterative process, sequential BSS (SQ-BSS) algorithm and successive BSS (SC-BSS) algorithm to find an optimal band subset numerically among all possible combinations out of the full band set. In order to terminate the search process the averaged least-squares error (ALSE) and 3-D receiver operating characteristic (3D ROC) curves are used as stopping criteria to evaluate performance relative to AD using the full band set. Experimental results demonstrate that BSS generally performs better background suppression while maintaining target detection capability compared to target detection using full band information.
Autors: Lin Wang;Chein-I Chang;Li-Chien Lee;Yulei Wang;Bai Xue;Meiping Song;Chuanyan Yu;Sen Li;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Sep 2017, volume: 55, issue:9, pages: 4887 - 4898
Publisher: IEEE
 
» Basis Expansion Approaches for Regularized Sequential Dictionary Learning Algorithms With Enforced Sparsity for fMRI Data Analysis
Abstract:
Sequential dictionary learning algorithms have been successfully applied to functional magnetic resonance imaging (fMRI) data analysis. fMRI data sets are, however, structured data matrices with the notions of temporal smoothness in the column direction. This prior information, which can be converted into a constraint of smoothness on the learned dictionary atoms, has seldomly been included in classical dictionary learning algorithms when applied to fMRI data analysis. In this paper, we tackle this problem by proposing two new sequential dictionary learning algorithms dedicated to fMRI data analysis by accounting for this prior information. These algorithms differ from the existing ones in their dictionary update stage. The steps of this stage are derived as a variant of the power method for computing the SVD. The proposed algorithms generate regularized dictionary atoms via the solution of a left regularized rank-one matrix approximation problem where temporal smoothness is enforced via regularization through basis expansion and sparse basis expansion in the dictionary update stage. Applications on synthetic data experiments and real fMRI data sets illustrating the performance of the proposed algorithms are provided.
Autors: Abd-Krim Seghouane;Asif Iqbal;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Sep 2017, volume: 36, issue:9, pages: 1796 - 1807
Publisher: IEEE
 
» BASS Net: Band-Adaptive Spectral-Spatial Feature Learning Neural Network for Hyperspectral Image Classification
Abstract:
Deep learning based land cover classification algorithms have recently been proposed in the literature. In hyperspectral images (HSIs), they face the challenges of large dimensionality, spatial variability of spectral signatures, and scarcity of labeled data. In this paper, we propose an end-to-end deep learning architecture that extracts band specific spectral-spatial features and performs land cover classification. The architecture has fewer independent connection weights and thus requires fewer training samples. The method is found to outperform the highest reported accuracies on popular HSI data sets.
Autors: Anirban Santara;Kaustubh Mani;Pranoot Hatwar;Ankit Singh;Ankur Garg;Kirti Padia;Pabitra Mitra;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Sep 2017, volume: 55, issue:9, pages: 5293 - 5301
Publisher: IEEE
 
» Bay Area Rapid Transit Extension South on the East Bay [Transportation Systems]
Abstract:
San Francisco's Bay Area Rapid Transit (BART) Warm Springs Extension opened for service on Saturday, 25 March 2017. The 5.4-mi extension connects the existing Fremont Station to the new Warm Springs/South Fremont Station.
Autors: Harvey Glickenstein;
Appeared in: IEEE Vehicular Technology Magazine
Publication date: Sep 2017, volume: 12, issue:3, pages: 12 - 16
Publisher: IEEE
 
» Bayesian Learning for Dynamic Feature Extraction With Application in Soft Sensing
Abstract:
Data-driven techniques such as principal component analysis (PCA) have been widely used to derive predictive models from historical data and applied for quality prediction in industry. Motivated by reducing data collinearity and extracting informative driving forces behind data, latent variable models are explored to facilitate the prediction by regressing data on a set of extracted features. In this paper, a novel learning strategy is proposed to build dynamic features under a full Bayesian framework, incorporating data information and prior knowledge of process dynamics. Unlike the traditional PCA that extracts features based on variances explained, in this paper, the latent features are extracted with the guidance of preferred velocities of nominal variations. By applying Bayesian learning algorithms, parameters are estimated with probability distributions accounting for corresponding uncertainties, and the number of latent features can be automatically determined by the variational Bayesian inference algorithm. The effectiveness and practicability of this Bayesian dynamic feature regression are demonstrated through simulated examples as well as an industrial case study.
Autors: Yanjun Ma;Biao Huang;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Sep 2017, volume: 64, issue:9, pages: 7171 - 7180
Publisher: IEEE
 
» Bayesian Optimal Data Detector for mmWave OFDM System With Low-Resolution ADC
Abstract:
Orthogonal frequency division multiplexing (OFDM) has been widely used in communication systems operating in the millimeter wave (mmWave) band to combat frequency-selective fading and achieve multi-Gbps transmissions, such as the IEEE 802.15.3c and the IEEE 802.11ad. For mmWave systems with ultra high sampling rate requirements, the use of low-resolution analog-to-digital converters (ADCs) (i.e., 1–3 bits) ensures an acceptable level of power consumption and system costs. However, orthogonality among subchannels in the OFDM system cannot be maintained because of the severe nonlinearity caused by low-resolution ADC, which renders the design of data detector challenging. In this paper, we develop an efficient algorithm for optimal data detection in the mmWave OFDM system with low-resolution ADCs. The analytical performance of the proposed detector is derived and verified to achieve the fundamental limit of the Bayesian optimal design. On the basis of the derived analytical expression, we further propose a power allocation (PA) scheme that seeks to minimize the average symbol error rate. In addition to the optimal data detector, we also develop a feasible channel estimation method, which can provide high-quality channel state information without significant pilot overhead. Simulation results confirm the accuracy of our analysis and illustrate that the performance of the proposed detector in conjunction with the proposed PA scheme is close to the optimal performance of the OFDM system with infinite-resolution ADC.
Autors: Hanqing Wang;Chao-Kai Wen;Shi Jin;
Appeared in: IEEE Journal on Selected Areas in Communications
Publication date: Sep 2017, volume: 35, issue:9, pages: 1962 - 1979
Publisher: IEEE
 
» Beamforming Optimization for Full-Duplex Wireless-Powered MIMO Systems
Abstract:
We propose techniques for optimizing transmit beamforming in a full-duplex multiple-input-multiple-output wireless-powered communication system, which consists of two phases. In the first phase, the wireless-powered mobile station (MS) harvests energy using signals from the base station (BS), whereas in the second phase, both MS and BS communicate to each other in a full-duplex mode. When complete instantaneous channel state information (CSI) is available, the BS beamformer and the time-splitting (TS) parameter of energy harvesting are jointly optimized in order to obtain the BS–MS rate region. The joint optimization problem is non-convex, however, a computationally efficient optimum technique, based upon semidefinite relaxation and line-search, is proposed to solve the problem. A sub-optimum zero-forcing approach is also proposed, in which a closed-form solution of TS parameter is obtained. When only the second-order statistics of transmit CSI is available, we propose to maximize the ergodic information rate at the MS while maintaining the outage probability at the BS below a certain threshold. An upper bound for the outage probability is also derived and an approximate convex optimization framework is proposed for efficiently solving the underlying non-convex problem. Simulations demonstrate the advantages of the proposed methods over the sub-optimum and half-duplex ones.
Autors: Batu Krishna Chalise;Himal A. Suraweera;Gan Zheng;George K. Karagiannidis;
Appeared in: IEEE Transactions on Communications
Publication date: Sep 2017, volume: 65, issue:9, pages: 3750 - 3764
Publisher: IEEE
 
» Benchmarking Si, SiGe, and III–V/Si Hybrid SIS Optical Modulators for Datacenter Applications
Abstract:
Recently, Si-photonics received a growing interest and started to move from laboratories to industrial product development, mainly for the applications inside data-centers. One of the weaknesses of Si is its relatively low plasma dispersion efficiency, making the size of phase modulator large. This efficiency can be improved by using the heterogeneous integration of material such as InP, InGaAsP, or SiGe to fabricate hybrid semiconductor–insulator–semiconductor (SIS) optical phase modulators. At the same time, the standard figure of merit for modulator benchmarking does not consider the dynamic behavior of the SIS devices, nor is making the link with the system level specifications such as optical modulation amplitude (OMA), widely used in 100G to 400G parallel single mode or coarse wavelength division multiplexing applications. In this paper, we propose to simply link the modulator performance to the OMA, to derive a compact model for SIS devices and to compare hybrid device performances for various materials.
Autors: Frederic Boeuf;Jae-Hoon Han;Shinichi Takagi;Mitsuru Takenaka;
Appeared in: Journal of Lightwave Technology
Publication date: Sep 2017, volume: 35, issue:18, pages: 4047 - 4055
Publisher: IEEE
 
» BER Analysis of SCMA Systems With Codebooks Based on Star-QAM Signaling Constellations
Abstract:
In this letter, the average bit error rate (BER) performance of sparse code multiple access (SCMA) systems with codebooks based on star quadrature amplitude modulation (star-QAM) signaling constellations over the additive white Gaussian noise channel is analyzed and evaluated. Motivated by the fact that the phase rotation plays an important role in designing codebooks and thus can significantly affect the BER performance in SCMA system, we derive a theoretical expression for the BER performance based on the statistics of the phase angle in SCMA constellations. Numerical and simulation results corroborate the proposed analysis.
Autors: Lisu Yu;Pingzhi Fan;Xianfu Lei;P. Takis Mathiopoulos;
Appeared in: IEEE Communications Letters
Publication date: Sep 2017, volume: 21, issue:9, pages: 1925 - 1928
Publisher: IEEE
 
» Beyond 200G Direct Detection Transmission With Nyquist Asymmetric Twin-SSB Signal at C-Band
Abstract:
For short reach and metro applications, single sideband (SSB) is a promising scheme due to its high spectral efficiency and tolerance to chromatic dispersion. In this study, we propose a novel asymmetric twin-SSB scheme based on Nyquist pulse shaping. Without joint equalization, the two sidebands can be separately detected with a small guard band. We experimentally demonstrate 224-Gb/s 16-ary quadrature amplitude modulation (16-QAM) asymmetric twin-SSB transmission with direct detection. After 240-km standard single mode fiber (SSMF) transmission, the bit error rates (BERs) of the right-sideband (RSB) and the left-sideband (LSB) are 3.2 × 10-3 and 2.8 × 10-3, respectively, which are below the 7% hard-decision forward error correction (HD-FEC) threshold of 3.8 × 10-3. The net bitrate is 203.7 Gb/s with consideration of both frame redundancy and HD-FEC overhead. To our best knowledge, we report the longest transmission distance for 200G single wavelength and single polarization direct detection systems. The advantages of the asymmetric twin-SSB scheme over the symmetric scheme are discussed through simulating the crosstalk resistance of both two schemes. We also demonstrate 300-Gb/s 32-QAM transmission over 80-km SSMF. The BERs of RSB and LSB are 1.50 × 10-2 and 1.61 × 10-2, respectively, which are below the 15% soft-decision forward error correction (SD-FEC) threshold of 1.8 × 10-2. The net bitrate is 254.3 Gb/s with consideration of both frame redundancy and SD-FEC overhead. To our best knowledge, it is the maximum bitrate ever reported for C-band 80-km single wavelength and single polarization direct detection transmission. The proposed scheme provides a useful and low-cost solution for high speed datacenter interconnection and metro-scale transmission.
Autors: Yixiao Zhu;Xiaoke Ruan;Kaiheng Zou;Fan Zhang;
Appeared in: Journal of Lightwave Technology
Publication date: Sep 2017, volume: 35, issue:17, pages: 3629 - 3636
Publisher: IEEE
 
» Big Search in Cyberspace
Abstract:
With the rapid development of big data analytics, mobile computing, Internet of Things, cloud computing, and social networking, cyberspace has expanded to a cross-fused and ubiquitous space made up of human beings, things, and information. Internet applications have evolved from Web 1.0 to Web 2.0 and Web 3.0, and web information has seen an explosive growth, which is strongly promoting the advent of a global era of big data. In this ubiquitous cyberspace, traditional search engines can no longer fully satisfy the evolving needs of various types of users. Therefore, search engines must make completely innovative, revolutionary changes for the next generation of search, which is referred to as “big search”. This paper first studies the development needs of big search. Then, big search is defined, and the 5S properties (Sourcing, Sensing, Synthesizing, Solution, and Security) of big search, which are different from those of traditional search engines, are elaborated. Also, the paper provides a system architecture for big search, explores the key technologies that support the 5S properties, and describes potential application fields of big search technology. Finally, the research opportunities of big search are discussed.
Autors: Binxing Fang;Yan Jia;Xiaoyong Li;Aiping Li;Xindong Wu;
Appeared in: IEEE Transactions on Knowledge and Data Engineering
Publication date: Sep 2017, volume: 29, issue:9, pages: 1793 - 1805
Publisher: IEEE
 
» Binary and Multi-Class Learning Based Low Complexity Optimization for HEVC Encoding
Abstract:
High Efficiency Video Coding (HEVC) improves the compression efficiency at the cost of high computational complexity by using the quad-tree coding unit (CU) structure and variable prediction unit (PU) modes. To minimize the HEVC encoding complexity while maintaining its compression efficiency, a binary and multi-class support vector machine (SVM)-based fast HEVC encoding algorithm is presented in this paper. First, the processes of recursive CU decision and PU selection in HEVC are modeled as hierarchical binary classification and multi-class classification structures. Second, according to the two classification structures, the CU decision and PU selection are optimized by binary and multi-class SVM, i.e., the CU and PU can be predicted directly via classifiers without intensive rate distortion (RD) cost calculation. In particular, to achieve better prediction performance, a learning method is proposed to combine the off-line machine learning (ML) mode and on-line ML mode for classifiers based on a multiple reviewers system. Additionally, the optimal parameters determination scheme is adopted for flexible complexity allocation under a given RD constraint. Experimental results show that the proposed method can achieve 68.3%, 67.3%, and 65.6% time saving on average while the values of Bjøntegaard delta peak signal-to-noise ratio are −0.093dB, −0.091dB, and −0.094dB and the values of Bjøntegaard delta bit rate are 4.191%, 3.842%, and 3.665% under low delay main, low delay main, and random access configurations, respectively, when compared with the HEVC test model version HM 16.5. Meanwhile, the proposed method outperforms the state-of-the-art fast coding algorithms in terms of complexity- reduction and RD performance.
Autors: Linwei Zhu;Yun Zhang;Zhaoqing Pan;Ran Wang;Sam Kwong;Zongju Peng;
Appeared in: IEEE Transactions on Broadcasting
Publication date: Sep 2017, volume: 63, issue:3, pages: 547 - 561
Publisher: IEEE
 
» Biocomputer and memory built inside living bacteria [News]
Abstract:
Scientists have come up with two clever new ways to harness the programming power of DNA in living bacterial cells. In separate experiments published in Nature in July, researchers reported that they had successfully archived a movie and built a complex biological computer inside living E. coli cells. The experiments expand our ability to exploit DNA's encoding potential. "What these papers represent is just how good we are getting at harnessing that power," says Julius Lucks, a bioengineer at the Center for Synthetic Biology, at Northwestern University, in Evanston, Ill., who was not involved in either report.
Autors: Emily Waltz;
Appeared in: IEEE Spectrum
Publication date: Sep 2017, volume: 54, issue:9, pages: 11 - 12
Publisher: IEEE
 
» Biofeedback for Gait Retraining Based on Real-Time Estimation of Tibiofemoral Joint Contact Forces
Abstract:
Biofeedback assisted rehabilitation and intervention technologies have the potential to modify clinically relevant biomechanics. Gait retraining has been used to reduce the knee adduction moment, a surrogate of medial tibiofemoral joint loading often used in knee osteoarthritis research. In this paper, we present an electromyogram-driven neuromusculoskeletal model of the lower-limb to estimate, in real-time, the tibiofemoral joint loads. The model included 34 musculotendon units spanning the hip, knee, and ankle joints. Full-body inverse kinematics, inverse dynamics, and musculotendon kinematics were solved in real-time from motion capture and force plate data to estimate the knee medial tibiofemoral contact force (MTFF). We analyzed five healthy subjects while they were walking on an instrumented treadmill with visual biofeedback of their MTFF. Each subject was asked to modify their gait in order to vary the magnitude of their MTFF. All subjects were able to increase their MTFF, whereas only three subjects could decrease it, and only after receiving verbal suggestions about possible gait modification strategies. Results indicate the important role of knee muscle activation patterns in modulating the MTFF. While this paper focused on the knee, the technology can be extended to examine the musculoskeletal tissue loads at different sites of the human body.
Autors: Claudio Pizzolato;Monica Reggiani;David J. Saxby;Elena Ceseracciu;Luca Modenese;David G. Lloyd;
Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Publication date: Sep 2017, volume: 25, issue:9, pages: 1612 - 1621
Publisher: IEEE
 
» Biologically Inspired Two-Stage Resource Management for Machine-Type Communications in Cellular Networks
Abstract:
Cellular technology has the potential to support large numbers of machine-type communications (MTC) devices for a variety of applications in fifth generation wireless systems. As MTC devices are a recent addition to cellular networks, a major concern is how to effectively manage and limit cellular resources for MTC data transmission without degrading traditional human-type communications (HTC) performance. To tackle this problem, a two-stage resource management framework is proposed with the goal of maintaining traffic equilibrium. In the first stage, an ecological prey-predator model is introduced to model the resource partition for the two types of devices. The steady-state properties of the traffic are analyzed, and the value regions of the allocated MTC resources for stable equilibrium points are derived. In the second stage, given an appropriate resource partition for MTC traffic, these devices are grouped based on their buffer conditions. The optimal resource allocation solution is derived so that the MTC traffic is stable. It is shown that to maintain MTC traffic stability, the resources can be allocated to only two groups. Furthermore, results are presented which show that HTC and MTC traffic can maintain a stable equilibrium using the two-stage resource management framework.
Autors: Zebing Feng;Zhiyong Feng;T. Aaron Gulliver;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Sep 2017, volume: 16, issue:9, pages: 5897 - 5910
Publisher: IEEE
 
» Biometric Surveillance and the Right to Privacy [Commentary]
Abstract:
Autors: Angus Willoughby;
Appeared in: IEEE Technology and Society Magazine
Publication date: Sep 2017, volume: 36, issue:3, pages: 41 - 45
Publisher: IEEE
 
» Bipolar Intracardiac Electrogram Active Interval Extraction During Atrial Fibrillation
Abstract:
Objective: We introduce novel methods to identify the active intervals (AIs) of intracardiac electrograms (IEGMs) during complex arrhythmias, such as atrial fibrillation (AF). Methods: We formulate the AI extraction problem, which consists of estimating the beginning and duration of the AIs, as a sequence of hypothesis tests. In each test, we compare the variance of a small portion of the bipolar IEGM with its adjacent segments. We propose modified general-likelihood ratio (MGLR) and separating-function-estimation tests; we derive five test statistics (TSs), and show that the AIs can be obtained by threshold crossing the TSs. We apply the proposed methods to the IEGM segments collected from the left atrium of 16 patients (62.4 8.2-years old, four females, four paroxysmal, and twelve persistent AF) prior to catheter ablation. The accuracy of our methods is evaluated by comparing them with previously developed methods and manual annotation (MA). Results: Our results show a high level of similarity between the AIs of the proposed methods and MA, e.g., the true and false positive rates of one of the MGLR-based methods were, respectively, 97.8% and 1.4%. The mean absolute error from estimation of the onset and end of AIs and also for the estimation of the mean cycle length for that approach was 8.7 10.5, 13 15.5, and 4.2 9.4 ms, respectively. Conclusion: The proposed methods can accurately identify onset and duration of AI of the IEGM during AF. Significance: The proposed methods can be used for real-time automated analysis of A- , the most challenging complex arrhythmia.
Autors: Mohammad Hassan Shariat;Saeed Gazor;Damian P. Redfearn;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Sep 2017, volume: 64, issue:9, pages: 2122 - 2133
Publisher: IEEE
 
» Bit-Level Probabilistically Shaped Coded Modulation
Abstract:
A routine to parallelize and increase the throughput of fixed length distribution matching with non-binary output alphabet is presented. The routine performs parallel distribution matchings with binary output alphabets, and then maps the binary output streams to symbols from the primary, non-binary alphabet. Fixed length distribution matching is essential for probabilistically shaped coded modulation (PSCM), such as the probabilistic amplitude shaping (PAS). In the PAS setup, the novel bit-level distribution matcher achieves similar rate-versus-SNR performance as the symbol-level constant composition distribution matcher, thus providing a high throughput solution for PSCM.
Autors: Marcin Pikus;Wen Xu;
Appeared in: IEEE Communications Letters
Publication date: Sep 2017, volume: 21, issue:9, pages: 1929 - 1932
Publisher: IEEE
 
» BLASST: Band Limited Atomic Sampling With Spectral Tuning With Applications to Utility Line Noise Filtering
Abstract:
Objective: In this paper, we present and test a new method for the identification and removal of nonstationary utility line noise from biomedical signals. Methods: The method, band limited atomic sampling with spectral tuning (BLASST), is an iterative approach that is designed to 1) fit nonstationarities in line noise by searching for best-fit Gabor atoms at predetermined time points, 2) self-modulate its fit by leveraging information from frequencies surrounding the target frequency, and 3) terminate based on a convergence criterion obtained from the same surrounding frequencies. To evaluate the performance of the proposed algorithm, we generate several simulated and real instances of nonstationary line noise and test BLASST along with alternative filtering approaches. Results: We find that BLASST is capable of fitting line noise well and/or preserving local signal features relative to tested alternative filtering techniques. Conclusion: BLASST may present a useful alternative to bandpass, notch, or other filtering methods when experimentally relevant features have significant power in a spectrum that is contaminated by utility line noise, or when the line noise in question is highly nonstationary. Significance: This is of particular significance in electroencephalography experiments, where line noise may be present in the frequency bands of neurological interest and measurements are typically of low enough strength that induced line noise can dominate the recorded signals. In conjunction with this paper, the authors have released a MATLAB toolbox that performs BLASST on real, vector-valued signals (available at https://github.com/VisLab/blasst).
Autors: Kenneth Ray Ball;W. David Hairston;Piotr J. Franaszczuk;Kay A. Robbins;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Sep 2017, volume: 64, issue:9, pages: 2276 - 2287
Publisher: IEEE
 
» BLE-Backscatter: Ultralow-Power IoT Nodes Compatible With Bluetooth 4.0 Low Energy (BLE) Smartphones and Tablets
Abstract:
Backscatter communication promises significant power and complexity advantages for Internet of Things devices such as radio frequency identification (RFID) tags and wireless sensor nodes. One perceived disadvantage of backscatter communication has been the requirement for specialized hardware such as RFID readers to receive backscatter signals. In this paper, we show how backscatter signals can be designed for compatibility with the Bluetooth 4.0 low energy (BLE) chipsets already present in billions of smart phones and tablets. We present a prototype microcontroller-based “BLE-Backscatter” tag that produces bandpass frequency-shift keying modulation at 1 Mb/s, enabling compatibility with conventional BLE advertising channels. Using a +23-dBm equivalent isotropically radiated power continuous wave (CW) carrier source, we demonstrate a range of up to 13 m between the tag and an unmodified Apple iPad Mini as well as a PC with the Nordic Semiconductor nRF51822 chipset. With the tag 1 m from the receiver, we demonstrate a range of up to 30 m between the CW carrier source and the tag. In both cases, the existing Bluetooth stack was used, with no modifications whatsoever to hardware, firmware, or software. The backscatter tag consumes only 1.56 nJ/b, over less than the lowest power commercial Bluetooth transmitters.
Autors: Joshua F. Ensworth;Matthew S. Reynolds;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Sep 2017, volume: 65, issue:9, pages: 3360 - 3368
Publisher: IEEE
 
» Blind Frequency Synchronization for OFDM Systems With I/Q Imbalance
Abstract:
The presence of carrier frequency offset (CFO) and in-phase/quadrature-phase (I/Q) imbalance results in inter-carrier interference and thus greatly degrades the performance of orthogonal frequency division multiplexing (OFDM) systems. In this paper, we propose a new blind frequency synchronization scheme for OFDM systems with frequency-independent I/Q imbalance. A blind and joint estimator of CFO and I/Q imbalance parameter is first proposed by exploiting the multi-antenna redundancy at the receiver. Estimation computational complexity is reduced by expressing the cost function as a superposition of very few harmonically related cosine waves. The compensation for CFO and I/Q imbalance can be further carried out, which generates an equivalent received signal model without CFO and I/Q imbalance distortion. In this way, the conventional channel estimation and data detection can be performed. The Cramer–Rao bound of the CFO estimation is derived as a benchmark. The CFO estimation with frequency-dependent I/Q imbalance is further addressed. We also provide extensive simulations to demonstrate the superiority of the proposed method over existing competitors.
Autors: Yue Meng;Weile Zhang;Wenjie Wang;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Sep 2017, volume: 66, issue:9, pages: 7862 - 7876
Publisher: IEEE
 
» Blind Source Separation of Event-Related EEG/MEG
Abstract:
Objective: Blind source separation (BSS) can be used to decompose complex electroencephalography (EEG) or magnetoencephalography data into simpler components based on statistical assumptions without using a physical model. Applications include brain–computer interfaces, artifact removal, and identifying parallel neural processes. We wish to address the issue of applying BSS to event-related responses, which is challenging because of nonstationary data. Methods: We introduce a new BSS approach called momentary-uncorrelated component analysis (MUCA), which is tailored for event-related multitrial data. The method is based on approximate joint diagonalization of multiple covariance matrices estimated from the data at separate latencies. We further show how to extend the methodology for autocovariance matrices and how to apply BSS methods suitable for piecewise stationary data to event-related responses. We compared several BSS approaches by using simulated EEG as well as measured somatosensory and transcranial magnetic stimulation (TMS) evoked EEG. Results: Among the compared methods, MUCA was the most tolerant one to noise, TMS artifacts, and other challenges in the data. With measured somatosensory data, over half of the estimated components were found to be similar by MUCA and independent component analysis. MUCA was also stable when tested with several input datasets. Conclusion: MUCA is based on simple assumptions, and the results suggest that MUCA is robust with nonideal data. Significance: Event-related responses and BSS are valuable and popular tools in neuroscience. Correctly designed BSS is an efficient way of identifying artifactual and neural processes from nonstationary event-related data.
Autors: Johanna Metsomaa;Jukka Sarvas;Risto Juhani Ilmoniemi;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Sep 2017, volume: 64, issue:9, pages: 2054 - 2064
Publisher: IEEE
 
» Blind transmitter IQ imbalance compensation in M-QaM optical coherent systems
Abstract:
We investigate transmitter IQ imbalance compensation based on the blind adaptive source separation (BASS) method in a dual-polarization M-QAM optical coherent system. The robustness of the BASS method against the residual carrier frequency offset (CFO) is numerically investigated and compared to that of the Gram-Schmidt or-thogonalization procedure (GSOP). We further validate experimentally the proposed method with 10 Gbaud optical 4-QaM and 16-QAM signals at 30° and 10° phase imbalance, respectively, with simulated impairments. More specifically, in the presence of 5 χ 10−6 residual CFO (normalized to the sample rate), the optical signal-to-noise ratio penalty reduction of the BASS method compared to the GSOP method is 1 dB for 4-QAM at a bit error ratio (BER) of 2 χ 10−3 and 2 dB for 16-QAM at a BER of 10−3. In contrast to the GSOP, which requires an independent block, the BASS method can be integrated into an equalizer, simplifying the operation and allowing parallel implementation.
Autors: Trung-Hien Nguyen;Pascal Scalart;Mathilde Gay;Laurent Bramerie;Olivier Sentieys;Jean-Claude Simon;Christophe Peucheret;Michel Joindot;
Appeared in: IEEE/OSA Journal of Optical Communications and Networking
Publication date: Sep 2017, volume: 9, issue:9, pages: D42 - D50
Publisher: IEEE
 
» Blocker-Tolerant and High-Sensitivity $\Delta \Sigma $ Correlation Digitizer for Radar and Coherent Receiver Applications
Abstract:
In this paper, a coherent subsampling digitizer for pulsed Doppler radar systems is proposed. Prior to transmission, the radar system modulates the RF pulse with a known pseudorandom binary phase shift keying (BPSK) sequence. Upon reception, the radar digitizer uses a programmable sample-and-hold circuit to multiply the received waveform by a properly time-delayed version of the known a priori BPSK sequence. This operation demodulates the desired echo signal while suppressing the spectrum of all in-band noncorrelated interferers, making them appear as noise in the frequency domain. The resulting demodulated narrowband Doppler waveform is then subsampled at the IF frequency by a delta–sigma modulator. Because the digitization bandwidth within the delta–sigma feedback loop is much less than the input bandwidth to the digitizer, the thermal noise outside of the Doppler bandwidth is effectively filtered prior to quantization, providing an increase in signal-to-noise ratio (SNR) at the digitizer’s output compared with the input SNR. In this demonstration, a delta–sigma correlation digitizer is fabricated in a 0.18- CMOS technology. The digitizer has a power consumption of 1.12 mW with an IIP3 of 7.5 dBm. The digitizer is able to recover Doppler tones in the presence of blockers up to 40 dBm greater than the Doppler tone.
Autors: John S. Mincey;Jose Silva-Martinez;Aydin Ilker Karşılayan;Christopher T. Rodenbeck;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Sep 2017, volume: 65, issue:9, pages: 3453 - 3463
Publisher: IEEE
 
» Bluefin tuna: Fast, but maybe not fast enough [Numbers Don't Lie]
Abstract:
CONSIDER THE TUNA: ITS NEAR-PERFECT HYDRODYNAMICS and efficient propulsion, powered by warm-blooded muscles deep within the body, make it an outstanding swimmer. The largest ones top 70 kilometers per hour, or around 40 knots-fast for a powerboat, and far faster than any known submarine. . But their size and tasty meatiness have put the most majestic of these fish on the road to extinction. The white meat you get in cans comes from the relatively abundant albacore, a small fish, typically less than 40 kilograms (red canned meat comes from the abundant skipjack, another small tuna). In contrast, bluefin (in Japanese, maguro or hon maguro, true tuna) has always been the rarest tuna. Adults can grow to more than 3 meters and weigh more than 600 kg.
Autors: Vaclav Smil;
Appeared in: IEEE Spectrum
Publication date: Sep 2017, volume: 54, issue:9, pages: 24 - 24
Publisher: IEEE
 
» Bluetooth Data in an Urban Context: Retrieving Vehicle Trajectories
Abstract:
Bluetooth sensors have recently been developed throughout the world for traffic information gathering. Primarily designed for travel time analysis, this article presents a method for vehicular trajectories retrieval. After a short description of some of the challenges at hand in using Bluetooth data in an urban network, a procedure to extract trip information from such data is proposed. It is further analyzed and illustrated at work on a real dataset collected in Brisbane. Last, this article shows that using spatially constrained shortest path analysis, this trip information, once extracted, can be used for the reconstruction of the trajectories. The performance of the process is assessed using both a simulated dataset and one from the real-world acquired in Brisbane, showing encouraging results, with up to 84% of accurately recovered trajectories.
Autors: Gabriel Michau;Alfredo Nantes;Ashish Bhaskar;Edward Chung;Patrice Abry;Pierre Borgnat;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: Sep 2017, volume: 18, issue:9, pages: 2377 - 2386
Publisher: IEEE
 
» Book Reviews [7 Reviews]
Abstract:
The following books are reviewed: Computational Intelligence Applications in Smart Grids by A.F. Zobaa and A. Vaccaro; Tailoring of Nanocomposite Dielectrics by T. Tanaka and A.S. Vaughan; Smart Microgrids-Lessons from Campus Microgrid Design and Implementation by H. Farhangi; Principles and Applications of Ubiquitous Sensing by W. Dargie; Understanding Symmetrical Components for Power System Modeling by J.C. Das; Internet of Things and Data Analytics Handbook by H. Geng; Physics of Digital Photography by A. Rowlands
Autors: John J. Shea;
Appeared in: IEEE Electrical Insulation Magazine
Publication date: Sep 2017, volume: 33, issue:5, pages: 56 - 59
Publisher: IEEE
 
» Booze-sniffing electronic nose showcases 3D nanosystems [News]
Abstract:
You'd think computers spend most of their time and energy doing...well, computation. But that's not the case: About 90 percent of a computer's execution time and electrical energy is spent transferring data between processing and memory, says Subhasish Mitra, a computer scientist at Stanford University. Even if Moore's Law continued indefinitely, computers would still be limited by this memory bottleneck.
Autors: Katherine Bourzac;
Appeared in: IEEE Spectrum
Publication date: Sep 2017, volume: 54, issue:9, pages: 14 - 14
Publisher: IEEE
 
» Boundary Stabilization of Wave Equation With Velocity Recirculation
Abstract:
Nonlocal terms have been the mainstay of the applications of partial differential equation (PDE) backstepping methods to parabolic PDEs. The problem of similar nonlocal terms for wave equations is still open. For wave equations, similar nonlocal terms have not been studied. In this paper, we open the topic of exploration of control of wave PDEs with nonlocal terms. This paper is concerned with the wave equation with in-domain feedback/recirculation of a boundary velocity with a spatially constant coefficient. Due to this nonlocal term, the passivity of the wave equation is destroyed. We first design an explicit state feedback controller to achieve exponential stability for the closed-loop system. Then, we design the output feedback by using infinite-dimensional observer. The backstepping approach is adopted in investigation. It is shown that by using two measurements only, the output feedback makes the closed-loop system exponentially stable.
Autors: Lingling Su;Wei Guo;Jun-Min Wang;Miroslav Krstic;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Sep 2017, volume: 62, issue:9, pages: 4760 - 4767
Publisher: IEEE
 
» Bounded Selective Spanning With Extended Fast Enumeration for MIMO-OFDM Systems Detection
Abstract:
Sphere decoders allow receivers in multiple-input multiple-output (MIMO) communications systems to detect QAM symbols with quasi-optimal accuracy and low complexity compared with the ideal maximum likelihood detector. However, their high complexity relative to simple linear detectors means that the latter are still usually adopted, despite their lower detection performance. Configurable sphere decoders, such as selective spanning fast enumeration (SSFE), allow complexity to be reduced at the cost of lower performance and are hence ideal for transceivers for Internet-of-Things equipment, where scale, operating context and resource, and energy budgets vary dramatically. However, SSFE still suffers performance limitations due to the internal heuristics employed for symbol selection and enumeration and real time, and software-defined realizations for even moderately demanding MIMO standards, such as 802.11n, have not been recorded. This paper presents a new variant of SSFE which, by employing novel fast symbol enumeration and modulation dictionary spanning heuristics, increases performance and computational efficiency to the point where very substantial reductions in resource can be achieved without impacting detection accuracy relative to SSFE. This is demonstrated via a series of field programmable gate array-based detectors and , 16-QAM 802.11n MIMO.
Autors: Yun Wu;John McAllister;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Sep 2017, volume: 64, issue:9, pages: 2556 - 2568
Publisher: IEEE
 
» Braided Convolutional Codes With Sliding Window Decoding
Abstract:
In this paper, we present a novel sliding window decoding scheme based on iterative Bahl–Cocke–Jelinek–Raviv decoding for braided convolutional codes, a class of turbo-like codes with short constraint length component convolutional codes. The tradeoff between performance and decoding latency is examined and, to reduce decoding complexity, both uniform and nonuniform message passing schedules within the decoding window, along with early stopping rules, are proposed. We also perform a density evolution analysis of sliding window decoding to guide the selection of the window size and message passing schedule. Periodic puncturing is employed to obtain rate-compatible code rates of 1/2 and 2/3 starting from a rate 1/3 mother code and a code rate of 3/4 starting from a rate 1/2 mother code. Simulation results show that, with nonuniform message passing and periodic puncturing, near capacity performance can be maintained throughout a wide range of rates with reasonable decoding complexity and no visible error floors.
Autors: Min Zhu;David G. M. Mitchell;Michael Lentmaier;Daniel J. Costello;Baoming Bai;
Appeared in: IEEE Transactions on Communications
Publication date: Sep 2017, volume: 65, issue:9, pages: 3645 - 3658
Publisher: IEEE
 
» Brain racers
Abstract:
IN OCTOBER 2016, inside a sold-out arena in Zurich, a man named Numa Poujouly steered his wheelchair up to the central podium. As the Swiss national anthem played, organizers of the world's first cyborg Olympics hung a gold medal around Poujouly's neck. The 30-yearold, who became paralyzed after a bicycle accident in his teens, had triumphed in the tournament's most futuristic event: a video-game-like race in which the competitors controlled their speeding avatars with just their minds.
Autors: Serafeim Perdikis;Luca Tonin;Jose del R. Millan;
Appeared in: IEEE Spectrum
Publication date: Sep 2017, volume: 54, issue:9, pages: 44 - 51
Publisher: IEEE
 
» Breakdown Characteristics and Mechanisms of Short Needle–Plate Air Gap in High-Speed Airflow
Abstract:
To understand the flashover of roof insulators in high-speed airflows, the breakdown characteristics and mechanisms of a short needle–plate air gap are investigated. An interesting and important phenomenon is found based on an artificial wind tunnel: the breakdown voltage first increases and then decreases. An experiential formula is established to describe the relationship among the airflow velocity, gap distance, and breakdown voltage. A good consistency with the experimental results is obtained. Furthermore, the breakdown mechanisms of the air gap in high-speed airflows are proposed, and the phenomenon is explained and verified according to the theories of gas discharge and fluid dynamics. The airflow blowing effect, which includes the deflection effect and blown away effect, and the airflow density effect are proposed as two dominant factors that affect the breakdown process of the air gap in high-speed airflows. The variation trend of the breakdown voltage with the airflow velocity is predicted. Two extreme points are expected during the variation process; i.e., the breakdown voltage has a maximum and a minimum, to which more attention should be paid. This paper is helpful for the safety operation of roof insulators on the high-speed train.
Autors: Yongqiang Kang;Xueqin Zhang;Chaoqun Shi;Yue Zhou;Yijie Liu;Guoqiang Gao;Wenfu Wei;Guangning Wu;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Sep 2017, volume: 45, issue:9, pages: 2406 - 2415
Publisher: IEEE
 
» Broadband Giant Group Velocity Dispersion in Asymmetric InP Dual Layer, Dual Width Waveguides
Abstract:
Highly dispersive components enable photonic-integrated circuits for ultrafast optical pulse processing. This paper presents the design of an InP device with resonant giant group velocity dispersion. The waveguides have a dual layer, dual width geometry that enables tailoring of the group velocity resonance wavelength. By cascading sections with different resonance wavelengths we show how constant group velocity dispersion can be achieved over a 50-nm wavelength range. Depending on which one of two super modes is excited in this device, the dispersion can be either normal or anomalous with values of -23200 ps/(nm · km) or 8200 ps/(nm · km), respectively. Mode converters with> 90% efficiency are designed to facilitate selective excitation of one or the other mode. The complete device is expected to be compatible with existing active/passive photonic integration technology in the InP/InGaAsP material system that should allow the creation of monolithic ultrafast optical pulse processing systems.
Autors: Jon Øyvind Kjellman;Ripalta Stabile;Kevin A. Williams;
Appeared in: Journal of Lightwave Technology
Publication date: Sep 2017, volume: 35, issue:17, pages: 3791 - 3800
Publisher: IEEE
 
» Broadband High-Gain Beam-Scanning Antenna Array for Millimeter-Wave Applications
Abstract:
A novel method of achieving low profile, broadband microstrip array antennas with high antenna gain is proposed for millimeter-wave applications. The element employs a novel third-order vertically coupled resonant structure that a U-slot resonator in the ground is used to couple with the feeding resonator and the radiating patch, simultaneously. This proposed structure can significantly improve the bandwidth and frequency selectivity without increasing the thickness of the antenna. Then, to achieve the subarray, a new wideband power divider with loaded resonators is employed, which can be used to further improve the bandwidth. To demonstrate the working schemes of broadside radiation and scanned beam, two array antennas are implemented on the same board. Measured results agree well with the simulations, showing a wide bandwidth from 22 to 32 GHz (FBW = 37%) with the gain of around 19 dBi. The beam-scanning array can realize a scanning angle of 25° over a broadband. In addition, due to the filtering features are integrated in the design, the proposed antenna could also reduce the complexity and potential cost of the frontends.
Autors: Chun-Xu Mao;Steven Gao;Yi Wang;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Sep 2017, volume: 65, issue:9, pages: 4864 - 4868
Publisher: IEEE
 
» Broadband Multibeam Antenna Arrays Fed by Frequency-Dependent Butler Matrices
Abstract:
A novel concept of multibeam antenna arrays operating in an octave frequency band has been presented. To achieve multiple beams in such a wide bandwidth N-element antenna arrays are fed by frequency-dependent Butler matrices which smoothly change their properties across the bandwidth. The proposed Butler matrices are designed in such a way that for the selected inputs their amplitude and differential phase characteristics feature the ones obtained for Butler matrices at , whereas at they feature the properties of Butler matrices. The proposed concept has been verified by measurements of a multibeam antenna array operating in 1.75–3.5 GHz frequency range and extended showing the possibility of designing antenna arrays with higher number of beams.
Autors: Krzysztof Wincza;Kamil Staszek;Slawomir Gruszczynski;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Sep 2017, volume: 65, issue:9, pages: 4539 - 4547
Publisher: IEEE
 
» Building the Foundation for "Generation Robot": Signal Processing is Helping to Make Robots a Part of Everyday Life [Special Reports]
Abstract:
Autors: John Edwards;
Appeared in: IEEE Signal Processing Magazine
Publication date: Sep 2017, volume: 34, issue:5, pages: 8 - 11
Publisher: IEEE
 
» Bulk-Silicon-Based Waveguides and Bends Fabricated Using Silicon Wet Etching: Properties and Limits
Abstract:
We develop a process of fabricating silicon waveguides and devices using a bulk silicon substrate. The fabrication process mainly consists of one silicon dry etching and one silicon wet etching. The use of silicon wet etching makes the process simple and inexpensive. Because of the anisotropic nature of silicon wet etching, the bulk-silicon-based (BSB) waveguide made by the process consists of an inverted-trapezoidal core on a rectangular pedestal and a trapezoidal base beneath the pedestal. In addition, geometrically smooth BSB waveguide bends can be achieved when the radii of curvature of the bends are sufficiently large. The propagation loss of the BSB waveguide depends on wet etching conditions and it is 4.0 or 0.79 dB/cm for transverse-magnetic polarization. It is confirmed that the minimum radius of curvature of the BSB waveguide bend is 500 μm. The BSB waveguides and bends are expected to be used to implement low-cost sensors with simple geometry.
Autors: Bonwoo Ku;Kyoung-Soo Kim;Yonghan Kim;Min-Suk Kwon;
Appeared in: Journal of Lightwave Technology
Publication date: Sep 2017, volume: 35, issue:18, pages: 3918 - 3923
Publisher: IEEE
 
» Bundled Kernels for Nonuniform Blind Video Deblurring
Abstract:
We present a novel blind video deblurring approach by estimating a bundle of kernels and applying the residual deconvolution. Our approach adopts multiple kernels to represent spatially varying motion blur, and thus can cope with nonuniform video deblurring. For each blurred frame, we build a warping-based, space-variant motion blur model based on a bundle of homographies in between its adjacent frames. Then, the nearest sharp frame is employed to form an unblurred-blurred pair for solving the motion model and obtain a bundle of kernels at the blurred frame. Finally, we apply the deconvolution on the residual between the warped unblurred frame and blurred frame with the kernels. The blur kernel estimation and residual deconvolution are iteratively performed toward the deblurred frame, as well as significantly reducing artifacts such as ringings. Experiments show that our approach can efficiently remove the nonuniform video blurring, and achieves better deblurring results than some state-of-the-art methods.
Autors: Lei Zhang;Le Zhou;Hua Huang;
Appeared in: IEEE Transactions on Circuits and Systems for Video Technology
Publication date: Sep 2017, volume: 27, issue:9, pages: 1882 - 1894
Publisher: IEEE
 
» Cache-Enabled Heterogeneous Cellular Networks: Optimal Tier-Level Content Placement
Abstract:
Caching popular contents at base stations (BSs) of a heterogeneous cellular network (HCN) avoids frequent information passage from content providers to the network edge, thereby reducing latency and alleviating traffic congestion in backhaul links. The potential of caching at the network edge for tackling 5G challenges has motivated recent studies on optimal content placement in large-scale HCNs. However, due to the complexity of the network performance analysis, the existing strategies were mostly based on approximation, heuristics, and intuition. In general, optimal strategies for content placement in HCNs remain largely unknown and deriving them forms the theme of this paper. To this end, we adopt the popular random HCN model, where tiers of BSs are modeled as independent Poisson point processes distributed in the plane with different densities. Furthermore, the random caching scheme is considered, where each of a given set of files with corresponding popularity measures is placed at each BS of a particular tier with a corresponding probability, called placement probability. The probabilities are identical for all BSs in the same tier but vary over tiers, giving the name tier-level content placement. We consider the network performance metric, hit probability, defined as the probability that a file requested by the typical user is delivered successfully to the user. Leveraging existing results on HCN performance, we maximize the hit probability over content placement probabilities, which yields the optimal tier-level placement policies. For the case of uniform received signal-to-interference (SIR) thresholds for successful transmissions for BSs in different tiers, the policy is in closed-form, - here the placement probability for a particular file is proportional to the square-root of the corresponding popularity measure with an offset depending on BS caching capacities. For the general case of non-uniform SIR thresholds, the optimization problem is non-convex and a sub-optimal placement policy is designed by approximation, which has a similar structure as in the case of uniform SIR thresholds and shown by simulation to be close-to-optimal.
Autors: Juan Wen;Kaibin Huang;Sheng Yang;Victor O. K. Li;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Sep 2017, volume: 16, issue:9, pages: 5939 - 5952
Publisher: IEEE
 
» Calendar [Calendar]
Abstract:
Autors: Amy Reeder;
Appeared in: IEEE Robotics & Automation Magazine
Publication date: Sep 2017, volume: 24, issue:3, pages: 183 - 183
Publisher: IEEE
 
» Calibration of Bulk Trap-Assisted Tunneling and Shockley–Read–Hall Currents and Impact on InGaAs Tunnel-FETs
Abstract:
The tunnel-FET (TFET) is a promising candidate for future low-power logic applications, because it enables a sub-60-mV/decadesubthresholdswing. However, themost experimental TFETs are plagued by unwanted trap-assisted tunneling (TAT) and Shockley–Read–Hall (SRH) carrier generation, which degrade the swing and increase the leakage floor, hence forming a major roadblock for TFET adoption. This degradation is attributed to bulk traps, semiconductor/oxideinterface traps, and/or heterojunction interface traps, but it is still unclear which of the three trap types are dominant. In this paper, we focus on TAT and SRH caused by bulk traps. We calibrate SRH and TAT models with the help of In0.53Ga0.47As p+/n+ and p+/i/n+ diodes grown on lattice matched substrates by molecular beam epitaxy (MBE). We then perform calibrated simulations of an In0.53Ga0.47As TFET, which show bulk SRH and TAT are sufficiently low compared with the target OFF-state current and, hence, not a significant issue. Therefore, it is likely that high SRH and TAT commonly observed in experimental homojunction InGaAs TFETs, MBE-grown on lattice matched substrates, are not caused by bulk semiconductor defects, but by semiconductor/oxide interface defects.
Autors: Quentin Smets;Anne S. Verhulst;Eddy Simoen;David Gundlach;Curt Richter;Nadine Collaert;Marc M. Heyns;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Sep 2017, volume: 64, issue:9, pages: 3622 - 3626
Publisher: IEEE
 
» Calibration of Floating-Gate SoC FPAA System
Abstract:
We present a calibration flow for a large-scale floating-gate (FG) system-on-chip field programmable analog array. We focus on characterizing the FG programming infrastructure and hot-electron injection parameters, MOSFET parameters using the EKV model, and calibrating digital-analog converters and analog-digital converters. In addition, threshold voltage mismatches on FG devices due to their indirect structure are characterized using on-chip measurement techniques. The calibration results in enabling a digital approach, where a design can be programmed without having to deal with the local and global mismatches, on a reconfigurable analog system. This paper shows the results of a compiled nonlinear classifier block comprising a vector-matrix-multiplier and a winner-takes-all on three different calibrated chips.
Autors: Sihwan Kim;Sahil Shah;Jennifer Hasler;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Sep 2017, volume: 25, issue:9, pages: 2649 - 2657
Publisher: IEEE
 
» Cameras, Music, and Synergy in Signal Processing [From the Editor]
Abstract:
Autors: Min Wu;
Appeared in: IEEE Signal Processing Magazine
Publication date: Sep 2017, volume: 34, issue:5, pages: 3 - 4
Publisher: IEEE
 
» Can a Non-Cognitive Learning Companion Increase the Effectiveness of a Meta-Cognitive Learning Strategy?
Abstract:
This project aimed to improve students’ learning and task performance using a non-cognitive learning companion in the context of both a tutor and a meta-tutor. The tutor taught students how to construct models of dynamic systems and the meta-tutor taught students a learning strategy. The non-cognitive learning companion was designed to increase students’ effort and persistence in using the learning strategy. It decided when to intervene and what to say using both log data and affective state monitoring via a facial expression camera and a posture sensor. Experiments with high school students showed that the non-cognitive learning companion increased students’ learning and performance. However, it had no effect on performance during a transfer phase in which the learning companion, meta-tutor, and tutor were all absent. The transfer phase null effect must be interpreted with caution due to low power, a possible floor effect, and other issues.
Autors: Kurt VanLehn;Lishan Zhang;Winslow Burleson;Sylvie Girard;Yoalli Hidago-Pontet;
Appeared in: IEEE Transactions on Learning Technologies
Publication date: Sep 2017, volume: 10, issue:3, pages: 277 - 289
Publisher: IEEE
 
» Capacitance, dc Voltage Utilizaton, and Current Stress: Comparison of Double-Line Frequency Ripple Power Decoupling for Single-Phase Systems
Abstract:
Double-line frequency ripple power is inherent in single-phase rectifiers and inverters, and, if not managed properly, it can be adverse to system performance at both the ac and dc sides. Therefore, numerous active power-decoupling techniques have been introduced to decouple the double-line frequency ripple power. However, no comprehensive comparisons are available on the permitted minimum capacitance for power decoupling, dc voltage utilization, current stress, modulation complexity, and even application evaluations, except for power rating and component counts. All of these aspects are critical when choosing appropriate power-decoupling techniques for different applications. In this article, the minimum capacitance to decouple the ripple power and the current stress of power devices in the main circuit are derived in light of different voltages across energy storage capacitors. By considering the ripple power paths, we investigate the dc voltage utilization of both the main circuit and power-decoupling circuit. Combined with other features, including component counts and modulation complexity, the overall characteristics of different power-decoupling techniques are compared and summarized to effectively evaluate their performance in different applications.
Autors: Haiyu Zhang;Xiao Li;Baoming Ge;Robert S. Balog;
Appeared in: IEEE Industrial Electronics Magazine
Publication date: Sep 2017, volume: 11, issue:3, pages: 37 - 49
Publisher: IEEE
 
» Capacitated Next Controller Placement in Software Defined Networks
Abstract:
Software defined networking shifts the control plane of forwarding devices to one or more external entities known as controllers. Determining the optimal location of controllers in the network and the assignment of switches to them is widely known as controller placement problem. In case of controller failures, the switches are disconnected from the controller until they are reassigned to other active controllers with enough spare capacity. However, there is a significant upsurge in the worst case latency after the reassignment due to lack of planning for controller failures. In this paper, we propose a controller placement strategy that not only considers reliability and capacity of controllers but also plans ahead for controller failures to avoid repeated administrative intervention, drastic increase in latency and disconnections. It is formulated as a mixed integer linear program. The objective is to minimize the maximum, for all switches, of the sum of the latency from the switch to the nearest controller with enough capacity (first reference controller) and the latency from the first reference controller to its closest controller with enough capacity (second reference controller). We also proposed a generalized model which can be used to minimize the average latency and extended it for multiple controller failures. Furthermore, we presented a simulated annealing heuristic that efficiently solves the problem on large scale networks. The proposed formulation and heuristic are evaluated on various networks from the Internet Topology Zoo. Simulation results show that our proposed method performs better than the controller placement that does not plan ahead for failures.
Autors: Bala Prakasa Rao Killi;Seela Veerabhadreswara Rao;
Appeared in: IEEE Transactions on Network and Service Management
Publication date: Sep 2017, volume: 14, issue:3, pages: 514 - 527
Publisher: IEEE
 
» Capacitor-Loaded Spoof Surface Plasmon for Flexible Dispersion Control and High-Selectivity Filtering
Abstract:
This letter proposes a new spoof surface plasmon transmission line (SSP-TL) using capacitor loading technique. This new SSP-TL features flexible and reconfigurable dispersion control and highly selective filtering performance without resorting to configuration change. Moreover, it requires much smaller linewidth than the conventional SSP-TL for achieving an extremely slow wave (or a highly confined field), which is quite useful for a compact system. To illustrate the design principle, several examples are designed within the frequency range of 2–8 GHz. Both numerical and experimental results are given in comparison with the conventional SSP-TL. It is demonstrated that the proposed technique provides a better performance in size reduction and dispersion reconfigurability.
Autors: Xiao-Lan Tang;Qingfeng Zhang;Sanming Hu;Abhishek Kandwal;Tongfeng Guo;Yifan Chen;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Sep 2017, volume: 27, issue:9, pages: 806 - 808
Publisher: IEEE
 
» Capacity Analysis of Discrete Energy Harvesting Channels
Abstract:
We study the channel capacity of a general discrete energy harvesting channel with a finite battery. Contrary to traditional communication systems, the transmitter of such a channel is powered by a device that harvests energy from a random exogenous energy source and has a finite-sized battery. As a consequence, at each transmission opportunity, the system can only transmit a symbol whose energy is no more than the energy currently available. This new type of power supply introduces an unprecedented input constraint for the channel, which is simultaneously random, instantaneous, and influenced by the full history of the inputs and the energy harvesting process. Furthermore, naturally, in such a channel, the energy information is observed causally at the transmitter. Both of these characteristics pose great challenges for the analysis of the channel capacity. In this paper, we use techniques developed for channels with side information and finite-state channels, to obtain lower and upper bounds on the capacity of energy harvesting channels. In particular, in a general case with Markov energy harvesting processes, we use stationarity and ergodicity theory to compute and optimize the achievable rates for the channels, and derive a series of computable capacity upper and lower bounds.
Autors: Wei Mao;Babak Hassibi;
Appeared in: IEEE Transactions on Information Theory
Publication date: Sep 2017, volume: 63, issue:9, pages: 5850 - 5885
Publisher: IEEE
 
» Capacity Configuration and Coordinated Operation of a Hybrid Wind Farm With FSIG-Based and PMSG-Based Wind Farms During Grid Faults
Abstract:
This paper mainly proposes a capacity configuration strategy for a hybrid wind farm with fixed-speed induction generator (FSIG)-based and permanent magnet synchronous generator (PMSG)-based wind farms during grid faults. In this paper, FSIG-based wind farm realizes low voltage ride through (LVRT) with the associated control of nearby PMSG systems as StatComs to provide the required reactive power. By establishing the mathematical model of hybrid wind farm containing network parameters, the operation characteristics of the FSIG-based wind farm during grid faults are analyzed in detail. Based on the characteristics and the critical clearing time of FSIG-based wind farm, a novel capacity configuration method for the hybrid wind farm is proposed to calculate the required reactive power of FSIG-based wind farm for a LVRT operation. Based on the capacity configuration result, the minimum installed capacity of PMSG-based wind farm could be determined. Taking into account the impact of reactive power compensation capacity and grid transmission line parameters, the coordinated LVRT capability of the hybrid wind farm is then analyzed. Finally, simulation and experimental results demonstrate the effectiveness of the proposed capacity configuration method and the coordinated operation performance of the hybrid wind farm respectively.
Autors: Jun Yao;Lisha Guo;Te Zhou;Depeng Xu;Ruikuo Liu;
Appeared in: IEEE Transactions on Energy Conversion
Publication date: Sep 2017, volume: 32, issue:3, pages: 1188 - 1199
Publisher: IEEE
 
» Capacity of Large-Scale Wireless Networks Under Jamming: Modeling and Analyses
Abstract:
Distributed jamming has important applications not only in the military context but also in the civilian context, where spectrum sharing is increasingly used and inadvertent jamming becomes a reality. In this paper, we derive the capacity bounds of wireless networks in the presence of jamming. We show that when the density of jammers is higher than that of target nodes by a certain threshold, the capacity of wireless networks approaches zero as the numbers of target nodes and jammers go to infinity. This is true even when the total power of target nodes is much higher than that of the jammers. We provide the optimal communication schemes to achieve the capacity bounds. We also describe the power efficiency of wireless networks, showing that there is an optimal target node density for power-efficient network operation. Our results can provide guidance for designing optimal wireless networking protocols that have to deal with large-scale distributed jamming.
Autors: Hong Huang;Yousef Jaradat;Satyajayant Misra;Amjad Abu-Baker;Rafael Asorey-Cacheda;Reza Tourani;Mohammad Masoud;Ismael Jannoud;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Sep 2017, volume: 66, issue:9, pages: 8524 - 8534
Publisher: IEEE
 
» Capacity of Multilevel NAND Flash Memory Channels
Abstract:
In this paper, we initiate a first information-theoretic study on multilevel NAND flash memory channels with intercell interference. More specifically, for a multilevel NAND flash memory channel under mild assumptions, we first prove that such a channel is indecomposable and it features asymptotic equipartition property; we then further prove that stationary processes achieve its information capacity, and consequently, as the order tends to infinity, its Markov capacity converges to its information capacity; eventually, we establish that its operational capacity is equal to its information capacity. Our results suggest that it is highly plausible to apply the ideas and techniques in the computation of the capacity of finite-state channels, which are relatively better explored, to that of the capacity of multilevel NAND flash memory channels.
Autors: Yonglong Li;Aleksandar Kavčić;Guangyue Han;
Appeared in: IEEE Transactions on Information Theory
Publication date: Sep 2017, volume: 63, issue:9, pages: 5934 - 5953
Publisher: IEEE
 
» Career Management: Ten Important Things to Keep in Mind
Abstract:
Your career can serve as an expression of who you are, what values you have, and what you seek to accomplish. Certainly compensation is a consideration. However, in my over 30 years as an engineer, manager, and executive in the electric utility industry, the most fulfilled, engaging, and passionate individuals I have met, regardless of "rank," have been those whose work was most closely aligned with their personal interests and beliefs.
Autors: Christopher E. Root;
Appeared in: IEEE Potentials
Publication date: Sep 2017, volume: 36, issue:5, pages: 13 - 16
Publisher: IEEE
 
» Careers in Signal Processing: A Diverse Field Impacting the Future [President's Message]
Abstract:
Autors: Rabab Ward;
Appeared in: IEEE Signal Processing Magazine
Publication date: Sep 2017, volume: 34, issue:5, pages: 5 - 11
Publisher: IEEE
 
» Carrier Aggregation of Three OFDM Signals Using a Single Oscillator and I/Q Modulator
Abstract:
In this paper, a novel method is presented, which makes carrier aggregation (CA) using a single local oscillator and an in-phase/quadrature (I/Q) modulator, possible. Three component carriers with orthogonal frequency division multiplexing are generated at 2.2, 2.5, and 2.9 GHz to show the feasibility of the method for the worst case scenario that is the interband CA. A special procedure to compensate the I/Q imbalances specific to this method is explained as well. Moreover, according to Nyquist criterion, the signal should have a sampling rate at least twice the signal highest frequency. In this method, the sampling rate of the digital-to-analog converter is significantly reduced, because, the baseband signal is distributed over negative and positive frequencies. In addition, the demodulation process of these frequency-aggregated signals using a three-phase demodulator is explained and experimental results are presented.
Autors: Mohammad Abdi Abyaneh;Bernard Huyart;Jean-Christophe Cousin;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Sep 2017, volume: 65, issue:9, pages: 3351 - 3359
Publisher: IEEE
 
» CDN-As-a-Service Provision Over a Telecom Operator’s Cloud
Abstract:
We present the design and implementation of a content-delivery-network-as-a-service (CDNaaS) architecture, which allows a telecom operator to open up its cloud infrastructure for content providers to deploy virtual content delivery network (CDN) instances on demand, at regions where the operator has presence. Using northbound REST APIs, content providers can express performance requirements and demand specifications, which are translated to an appropriate service placement on the underlying cloud substrate. Our architecture is extensible, supporting various different CDN flavors, and, in turn, different schemes for cloud resource allocation and management. In order to decide on the latter in an optimal manner from an infrastructure cost and a service quality perspective, knowledge of the performance capabilities of the underlying technologies, and compute resources is critical. Therefore, to gain insight which can be applied to the design of such mechanisms, but also with further implications on service pricing and SLA design, we carry out a measurement campaign to evaluate the capabilities of key enabling technologies for CDNaaS provision. In particular, we focus on virtualization and containerization technologies for implementing virtual CDN functions to deliver a generic HTTP service, as well as an HTTP video streaming one, empirically capturing the relationship between performance and service workload, both from a system operator and a user-centric viewpoint.
Autors: Pantelis A. Frangoudis;Louiza Yala;Adlen Ksentini;
Appeared in: IEEE Transactions on Network and Service Management
Publication date: Sep 2017, volume: 14, issue:3, pages: 702 - 716
Publisher: IEEE
 
» Celestial Signals: Are Low-Noise Amplifiers the Future for Millimeter-Wave Radio Astronomy Receivers?
Abstract:
Radio emission emanating from celestial sources was first detected by Karl Jansky during the 1930s. Using primitive radio instrumentation coupled to a relatively small aperture telescope, Jansky mapped portions of the Milky Way and established the field of radio astronomy. Thus was born a branch of modern astrophysics that has allowed the study of radio emission from cosmic sources and revolutionized our understanding of the universe.
Autors: David Cuadrado-Calle;Danielle George;Brian Ellison;Gary A. Fuller;Keiran Cleary;
Appeared in: IEEE Microwave Magazine
Publication date: Sep 2017, volume: 18, issue:6, pages: 90 - 99
Publisher: IEEE
 
» Cell-Like Spiking Neural P Systems With Request Rules
Abstract:
Cell-like spiking neural (cSN) P systems are a class of distributed and parallel computation models inspired by both the way in which neurons process information and communicate to each other by means of spikes and the compartmentalized structures of living cells. cSN P systems have been proved to be Turing universal if more spikes can be produced by consuming some spikes or spikes can be replicated. In this paper, in order to answer the open problem whether this functioning of producing more spikes and replicating spikes can be avoided by using some strategy without the loss of computation power, we introduce cSN P systems with request rules, which have classical spiking rules and forgetting rules, and also request rules in the skin membrane. The skin membrane can receive spikes from the environment by the application of request rules. cSN P systems with request rules are proved to be Turing universal. The results show that the decrease of computation power caused by removing the internal functioning of producing more spikes and replicating spikes can be compensated by request rules, which suggests that the communication between a cell and the environment is an essential ingredient of systems in terms of computation power.
Autors: Linqiang Pan;Tingfang Wu;Yansen Su;Athanasios V. Vasilakos;
Appeared in: IEEE Transactions on NanoBioscience
Publication date: Sep 2017, volume: 16, issue:6, pages: 513 - 522
Publisher: IEEE
 
» Centralized Energy-Efficient Multiuser Multiantenna Relaying in Next-Generation Radio Access Networks
Abstract:
This paper addresses the design of a multiuser relaying subnetwork within a cloud radio access network (C-RAN) from an energy-efficient perspective. In the relaying subnetwork, multiple source–destination pairs communicate with the assistance of multiple remote radio heads (RRHs) connected to the baseband unit pool. Exploiting the flexible centralized processing structure of C-RAN, where RRHs can be adaptively activated/deactivated, we formulate the problem as a quality-of-service (QoS) based network energy minimization problem via joint RRH selection and relaying matrix optimization. Since the resultant optimization problem is nonconvex and mathematically challenging, we propose an iterative solution based on the concept of the re-weighted norm, along with a block-coordinate descent type algorithm. The active RRHs are then determined in a single attempt by thresholding a group sparsity pattern associated with the set of all RRH relaying matrices. To circumvent a potentially undesirable condition, where the selected subset of RRHs fails to simultaneously satisfy all the destination users’ QoS levels, we conceive a UE admission control mechanism for overcoming the associated infeasibility problem. Our simulation results demonstrate the explicit benefits of the proposed design approach, which results in a significantly lower energy consumption of the relaying subnetwork than conventional cooperative relaying.
Autors: Jiaxin Yang;Benoit Champagne;Yulong Zou;Lajos Hanzo;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Sep 2017, volume: 66, issue:9, pages: 7913 - 7924
Publisher: IEEE
 
» Centralized Random Backoff for Collision Resolution in Wi-Fi Networks
Abstract:
Wi-Fi devices operate following the 802.11 distributed coordination function in order to fairly use the channel that the devices share. However, the throughput performance of the Wi-Fi networks is known to be degraded due to packet collisions. So, we propose a novel multiple access protocol, called centralized random backoff (CRB) for collision-free Wi-Fi networks. In CRB, after a successful reception of a data frame from a station, the access point allocates a unique backoff state to the station by means of the ACK frame. We evaluate its performance by comparing to that of a deterministic backoff mechanism. Evaluation results show that CRB significantly improves the throughput performance by reducing collisions, and it allows a larger number of nodes to operate in a collision-free state without dynamic parameter adjustment.
Autors: Jinho D. Kim;David I. Laurenson;John S. Thompson;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Sep 2017, volume: 16, issue:9, pages: 5838 - 5852
Publisher: IEEE
 
» Challenge Your Limits [Pathways]
Abstract:
Discusses the importance of an education despite the challenges that people may face in order to achieve their career goals.
Autors: David Eng;
Appeared in: IEEE Industry Applications Magazine
Publication date: Sep 2017, volume: 23, issue:5, pages: 76 - 77
Publisher: IEEE
 
» Challenging the Best HEVC Fractional Pixel FPGA Interpolators With Reconfigurable and Multifrequency Approximate Computing
Abstract:
Applicable in different fields and markets, low energy high efficiency video coding (HEVC) codecs and their constituting elements have been heavily studied. Fractional pixel interpolation is one of its most costly blocks. In this letter, a field programmable gate array implementation of HEVC fractional pixel interpolation, outperforming literature solutions, is proposed. Approximate computing, in conjunction with hardware reconfiguration, guarantees a tunable interpolation system offering an energy versus quality tradeoff to further reduce energy.
Autors: Carlo Sau;Francesca Palumbo;Maxime Pelcat;Julien Heulot;Erwan Nogues;Daniel Menard;Paolo Meloni;Luigi Raffo;
Appeared in: IEEE Embedded Systems Letters
Publication date: Sep 2017, volume: 9, issue:3, pages: 65 - 68
Publisher: IEEE
 
» Chance-Constrained AC Optimal Power Flow for Distribution Systems With Renewables
Abstract:
This paper focuses on distribution systems featuring renewable energy sources (RESs) and energy storage systems, and presents an AC optimal power flow (OPF) approach to optimize system-level performance objectives while coping with uncertainty in both RES generation and loads. The proposed method hinges on a chance-constrained AC OPF formulation, where probabilistic constraints are utilized to enforce voltage regulation with prescribed probability. A computationally more affordable convex reformulation is developed by resorting to suitable linear approximations of the AC power-flow equations as well as convex approximations of the chance constraints. The approximate chance constraints provide conservative bounds that hold for arbitrary distributions of the forecasting errors. An adaptive strategy is then obtained by embedding the proposed AC OPF task into a model predictive control framework. Finally, a distributed solver is developed to strategically distribute the solution of the optimization problems across utility and customers.
Autors: Emiliano Dall’Anese;Kyri Baker;Tyler Summers;
Appeared in: IEEE Transactions on Power Systems
Publication date: Sep 2017, volume: 32, issue:5, pages: 3427 - 3438
Publisher: IEEE
 
» Chance-Constrained Two-Stage Unit Commitment Under Uncertain Load and Wind Power Output Using Bilinear Benders Decomposition
Abstract:
In this paper, we study unit commitment (UC) problems considering the uncertainty of load and wind power generation. UC problem is formulated as a chance-constrained two-stage stochastic programming problem where the chance constraint is used to restrict the probability of load imbalance. In addition to the conventional mixed integer linear programming formulation using Big-M, we present the bilinear mixed integer formulation of chance constraint, and then derive its linear counterpart using the McCormick linearization method. Then, we develop a bilinear variant of the Benders decomposition method, which is an easy-to-implement algorithm, to solve the resulting large-scale linear counterpart. Our results on typical IEEE systems demonstrate that (i) the bilinear mixed integer programming formulation is stronger than the conventional one and (ii) the proposed Benders decomposition algorithm is generally an order of magnitude faster than using a professional solver to directly compute both linear and bilinear chance-constrained UC models.
Autors: Yao Zhang;Jianxue Wang;Bo Zeng;Zechun Hu;
Appeared in: IEEE Transactions on Power Systems
Publication date: Sep 2017, volume: 32, issue:5, pages: 3637 - 3647
Publisher: IEEE
 
» Change is Afoot: Applying Change Management Theories to Self-Organizing Socio-Technical Systems
Abstract:
Socio-technical systems are here to stay. They are going to become more important and more engrained in our daily lives. Even the relatively mundane examples we see these days have transformed the way we communicate, look up, and share knowledge, and the ways we choose our restaurants, our rides, and our vacations. Computersupported cooperative work is already transforming the workplace. Personal health and fitness applications allow us to observe our bodies and share this information within a social network that provides both praise and control. Larger-scale solutions are right around the corner. The technical feasibility of such systems is no longer under debate. Users seem to be willing to give up their data and at least some control for the benefits these socio-technical systems undoubtedly bring.
Autors: Jan-Philipp Steghofer;
Appeared in: IEEE Technology and Society Magazine
Publication date: Sep 2017, volume: 36, issue:3, pages: 56 - 62
Publisher: IEEE
 
» Changes to the Editorial Board
Abstract:
Prof. Jurriaan Schmitz has decided to step down from the editorial board. On behalf of IEEE Electron Device Letters staff and readers, I would like to express appreciation for his diligent service to the journal over the past five years.
Autors: Tsu-Jae King Liu;
Appeared in: IEEE Electron Device Letters
Publication date: Sep 2017, volume: 38, issue:9, pages: 1191 - 1191
Publisher: IEEE
 
» Channel Coding for Nonvolatile Memory Technologies: Theoretical Advances and Practical Considerations
Abstract:
Every bit of information in a storage or memory device is bound by a multitude of performance specifications, and is subject to a variety of reliability impediments. At the other end, the physical processes tamed to remember our bits offer a constant source of risk to their reliability. These include a variety of noise sources, access restrictions, intercell interferences, cell variabilities, and many more issues. Tying together this vector of performance figures with that vector of reliability issues is a rich matrix of emerging coding tools and techniques. Channel coding schemes ensure target reliability and performance and have been at the core of memory systems since their nascent age. In this survey, we first overview the fundamentals of channel coding and summarize well-known codes that have been used in nonvolatile memories (NVMs). Next, we demonstrate why the conventional coding approaches ubiquitously based on symmetric channel models and optimization for the Hamming metric fail to address the needs of modern memories. We then discuss several recently proposed innovative coding schemes. Behind each coding scheme lies an interesting theoretical framework, building on deep ideas from mathematics and the information sciences. We also survey some of the most fascinating bridges between deep theory and storage performance. While the focus of this survey is primarily on the pervasive multilevel NAND Flash, we envision that other benefiting memory technologies will include phase change memory, resistive memories, and others.
Autors: Lara Dolecek;Yuval Cassuto;
Appeared in: Proceedings of the IEEE
Publication date: Sep 2017, volume: 105, issue:9, pages: 1705 - 1724
Publisher: IEEE
 
» Channel Estimation for 3-D Lens Millimeter Wave Massive MIMO System
Abstract:
Channel estimation for 3-D lens millimeter wave massive MIMO system is investigated. First, the structure of beamspace channel is analyzed to show that the dominant entries of beamspace channel matrix form a dual crossing (DC) shape. Then, a DC-based channel estimation algorithm is proposed to iteratively refine the selection of dominant entries until the stop condition is met. Simulation results show that the DC-based algorithm outperforms the existing algorithms, including orthogonal matching pursuit and adaptive support detection (ASD). At signal-to-noise ratio of 15 dB, the DC-based algorithm has 57.7% improvement in terms of normalized mean squared error compared with ASD while the computational complexity is only half of ASD due to fast computation of least squares estimation.
Autors: Wenyan Ma;Chenhao Qi;
Appeared in: IEEE Communications Letters
Publication date: Sep 2017, volume: 21, issue:9, pages: 2045 - 2048
Publisher: IEEE
 
» Channel Estimation for Hybrid Architecture-Based Wideband Millimeter Wave Systems
Abstract:
Hybrid analog and digital precoding allows millimeter wave (mmWave) systems to achieve both array and multiplexing gain. The design of the hybrid precoders and combiners, though, is usually based on the knowledge of the channel. Prior work on mmWave channel estimation with hybrid architectures focused on narrowband channels. Since mmWave systems will be wideband with frequency selectivity, it is vital to develop channel estimation solutions for hybrid architectures-based wideband mmWave systems. In this paper, we develop a sparse formulation and compressed sensing-based solutions for the wideband mmWave channel estimation problem for hybrid architectures. First, we leverage the sparse structure of the frequency-selective mmWave channels and formulate the channel estimation problem as a sparse recovery in both time and frequency domains. Then, we propose explicit channel estimation techniques for purely time or frequency domains and for combined time/frequency domains. Our solutions are suitable for both single carrier-frequency domain equalization and orthogonal frequency-division multiplexing systems. Simulation results show that the proposed solutions achieve good channel estimation quality, while requiring small training overhead. Leveraging the hybrid architecture at the transceivers gives further improvement in estimation error performance and achievable rates.
Autors: Kiran Venugopal;Ahmed Alkhateeb;Nuria González Prelcic;Robert W. Heath;
Appeared in: IEEE Journal on Selected Areas in Communications
Publication date: Sep 2017, volume: 35, issue:9, pages: 1996 - 2009
Publisher: IEEE
 
» Channel Gain Cartography for Cognitive Radios Leveraging Low Rank and Sparsity
Abstract:
Channel gain cartography aims at inferring the channel gains between two arbitrary points in space based on the measurements (samples) of the gains collected by a set of radios deployed in the area. Channel gain maps are useful for various sensing and resource allocation tasks essential for the operation of cognitive radio networks. In this paper, the channel gains are modeled as the tomographic accumulations of an underlying spatial loss field (SLF), which captures the attenuation in the signal strength due to the obstacles in the propagation path. In order to estimate the map accurately with a relatively small number of measurements, the SLF is postulated to have a low-rank structure possibly with sparse deviations. Efficient batch and online algorithms are derived for the resulting map reconstruction problem. Comprehensive tests with both synthetic and real data sets corroborate that the algorithms can accurately reveal the structure of the propagation medium, and produce the desired channel gain maps.
Autors: Donghoon Lee;Seung-Jun Kim;Georgios B. Giannakis;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Sep 2017, volume: 16, issue:9, pages: 5953 - 5966
Publisher: IEEE
 
» Channel Pre-Inversion and Max-SINR Vector Perturbation for Large-Scale Broadcast Channels
Abstract:
We study channel pre-inversion and vector perturbation (VP) schemes for large-scale broadcast channels, wherein a transmitter has transmit antennas and is transmitting to single-antenna non-cooperating receivers. We provide results which predict the capacity of MMSE pre-inversion as . We construct a new VP strategy, max-SINR VP (MSVP), which maximizes a sharp estimate of the signal-to-interference-plus-noise ratio. We provide results which predict the performance of MSVP and demonstrate that MSVP outperforms other VP methods. Lastly, we combine MSVP with the low-complexity sorted QR precoding method to show that MSVP has the potential to efficiently deliver data to a very large number of users at close to channel capacity.
Autors: David A. Karpuk;Peter Moss;
Appeared in: IEEE Transactions on Broadcasting
Publication date: Sep 2017, volume: 63, issue:3, pages: 494 - 506
Publisher: IEEE
 
» Channels With Cooperation Links That May Be Absent
Abstract:
It is well known that cooperation between users in a communication network can lead to significant performance gains. A common assumption in past works is that all the users are aware of the resources available for cooperation, and know exactly to what extent these resources can be used. Unfortunately, in many modern communication networks, the availability of cooperation links cannot be guaranteed a priori, due to the dynamic nature of the network. In this paper, a family of models is suggested where the cooperation links may or may not be present. Coding schemes are devised that exploit the cooperation links if they are present, and can still operate (although at reduced rates) if cooperation is not possible.
Autors: Wasim Huleihel;Yossef Steinberg;
Appeared in: IEEE Transactions on Information Theory
Publication date: Sep 2017, volume: 63, issue:9, pages: 5886 - 5906
Publisher: IEEE
 
» Characteristic Analysis of Subsynchronous Resonance in Practical Wind Farms Connected to Series-Compensated Transmissions
Abstract:
The emerging subsynchronous resonance (SSR) caused by the interaction of wind turbine generators (WTGs) with series compensation has aroused great concerns. For this particular issue, this paper is aimed to fill the gap between theoretical studies and actual observations. By analyzing the field data of 58 SSR events captured in a practical wind power system and examining the observed dynamics with previous theoretical results, the mechanism and characteristics of SSR are revealed in a more explicit and substantial way. The necessary conditions and dominant influential factors are identified and the underlying reasons are discovered. Theoretically derived as well as practically measured impedance models have demonstrated that the converter control of doubly fed induction generator (DFIG) produces negative resistance at the slip frequency and thus causes unstable SSR; while permanent magnet synchronous generators and self-excited induction generators are just passively engaged in those SSR incidents. The distribution of the oscillation frequency has also been examined with field measurements. It is discovered that WTGs at different locations participate into the same SSR mode and their frequencies are not fixed but keep changing with the time, the variation of grid topology, and the number of online generators.
Autors: Xiaorong Xie;Xu Zhang;Huakun Liu;Hui Liu;Yunhong Li;Chuanyu Zhang;
Appeared in: IEEE Transactions on Energy Conversion
Publication date: Sep 2017, volume: 32, issue:3, pages: 1117 - 1126
Publisher: IEEE
 
» Characteristics and Restraining Method of Fast Transient Inrush Fault Currents in Synchronverters
Abstract:
Large transient inrush fault current in a synchronverter during a short-circuit fault can potentially damage the inverter and cause grid instability. It is therefore important to study the characteristics of and the way to restrain the inrush fault current. This paper investigates the characteristics of the synchronverter inrush fault current and proposes a new control method based on mode switching to protect synchronverters. First, an ideal voltage source inverter instantaneous inrush current calculation method for a grid symmetrical short circuit is discussed. Then, based on the inertia of synchronverter, the approximate calculation of the synchronverter instantaneous inrush current is described. The results show that the synchronverter's inrush current mainly consists of a gradually attenuated periodic component and a dc component when the phased voltage symmetry is lost. In our proposed new control approach, the synchronverter switches to the hysteresis controller to limit the output current quickly while staying connected to the grid, and supporting the grid voltage simultaneously. Simulation and experiment results verify the validity of the theoretical analysis.
Autors: Zhikang Shuai;Wen Huang;Chao Shen;Jun Ge;Z. John Shen;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Sep 2017, volume: 64, issue:9, pages: 7487 - 7497
Publisher: IEEE
 
» Characteristics of Planar and Conformal Contact GaAs Core–Shell Nanowire Array Solar Cells
Abstract:
As the transparent contact in radial p-n junction core-shell nanowire array solar cells can be either planar or conformal, the characteristics of these two types of device structure would be very different since conformal contact gives rise to severe band bending. Although radial p-n junction GaAs core-shell nanowire array solar cell with conformal transparent contact has been briefly inferred to have an inferior performance compared to the same nanowire array solar cell with planar transparent contact, the characteristics of these two types of radial p-n junction core-shell nanowire array solar cells are not known. Furthermore, it is unknown how the performance of these two types of solar cell compares with each other when the nanowire design parameters are optimized according to device physics of these two types of solar cell. In this paper, it is shown that radial p-n junction GaAs core-shell nanowire array solar cells with planar transparent contact are prone to carrier avalanche breakdown, and hence have a limited range of doping density. On the other hand, carrier diffusion in radial p-n junction GaAs core-shell nanowire array solar cells with conformal transparent contact is poor and hence requires a high doping to the core in order to increase the output voltage. All in all, this paper reveals that either type of transparent contact structure yields essentially the same energy conversion efficiency as long as the radial p-n junction GaAs core-shell nanowires are designed to suit the device physics of the type of transparent contact.
Autors: Cheng Guan Lim;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Sep 2017, volume: 64, issue:9, pages: 3696 - 3705
Publisher: IEEE
 
» Characterization and Modeling of K-Band Coplanar Waveguides Digitally Manufactured Using Pulsed Picosecond Laser Machining of Thick-Film Conductive Paste
Abstract:
Microdispensing of thick-film conductive paste has been demonstrated as a viable approach for manufacturing microwave planar transmission lines. However, the performance and upper frequency range of these lines is limited by the cross-sectional shape and electrical conductivity of the printed paste, as well as the achievable minimum feature size which is typically around . In this paper, a picosecond Nd:YAG laser is used to machine slots in a 20–25--thick layer of silver paste (Dupont CB028) that is microdispensed on a Rogers RT5870 substrate, producing coplanar waveguide (CPW) transmission lines with 16–-wide slots. It is shown that the laser solidifies an about 2--wide region of the edges of the slots, thus significantly increasing the effective conductivity of the film and improving the attenuation constant of the lines. The extracted attenuation constant at 20 GHz for laser machined CB028 is 0.74 dB/cm. CPW resonators and filters show that the effective conductivity is in the range from 10 to 30 MS/m, which represents a improvement when compared to the values obtained with the exclusive use of microdispensing. This paper demonstrates that a hybrid approach of additive manufacturing and laser machining enables the fabrication of higher frequency circuits (up to at least 40 GHz) with improved performance.
Autors: Eduardo A. Rojas-Nastrucci;Harvey Tsang;Paul I. Deffenbaugh;Ramiro A. Ramirez;Derar Hawatmeh;Anthony Ross;Kenneth Church;Thomas M. Weller;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Sep 2017, volume: 65, issue:9, pages: 3180 - 3187
Publisher: IEEE
 
» Characterization and Modeling of the Wind Turbine Radar Signature Using Turbine State Telemetry
Abstract:
Wind turbine observations and characterization efforts have treated the wind turbine as a noncooperative target. Similarly, suppression of the turbine’s radar signature has been considered without the aid of state information from the wind turbine under observation. In this paper, X-band radar observations of a utility-scale wind turbine, with detailed turbine state telemetry, are investigated. From scattering theory, the wind turbine’s physical structure has a deterministic radar cross section for a given observation geometry. Using the telemetry, the variation in the turbine’s signature is considered over a range of operating states. The deterministic nature of a turbine’s signature is demonstrated from radar observations, and a model is developed to isolate it. The turbine’s radar signature, as it relates to changes in the operating state, is discussed with the intent of enabling future suppression techniques.
Autors: Robert M. Beauchamp;V. Chandrasekar;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Sep 2017, volume: 55, issue:9, pages: 5134 - 5147
Publisher: IEEE
 
» Characterization and Optimization of a High-Efficiency AlGaAs-On-Insulator-Based Wavelength Converter for 64- and 256-QAM Signals
Abstract:
In this paper, we demonstrate wavelength conversion of advanced modulation formats such as 10-GBd 64-QAM and 256-QAM with high conversion efficiency over a 29-nm spectral window by using four-wave mixing in an AlGaAs-on-insulator (AlGaAsOI) nanowaveguide. A thorough characterization of the wavelength converter is reported, including the optimization of the AlGaAsOI nanowaveguide in terms of conversion efficiency and associated bandwidth and the analysis of the impact of the converter pump quality and power as well as the signal input power. The optimized converter enables generating idlers with optical signal-to-noise ratio (OSNR) above 30 dB over a 29-nm bandwidth leading to error-free conversion of 64-QAM and 256-QAM with OSNR penalty below 1.0 dB and 2.0 dB, respectively. The generated idlers exhibit an OSNR margin to the chosen forward error correction thresholds of >3 dB and >7 dB for 64-QAM and 256-QAM, respectively, that can be used for transmission after conversion.
Autors: Francesco Da Ros;Metodi P. Yankov;Edson P. da Silva;Minhao Pu;Luisa Ottaviano;Hao Hu;Elizaveta Semenova;Søren Forchhammer;Darko Zibar;Michael Galili;Kresten Yvind;Leif K. Oxenløwe;
Appeared in: Journal of Lightwave Technology
Publication date: Sep 2017, volume: 35, issue:17, pages: 3750 - 3757
Publisher: IEEE
 
» Characterization of an NTD Double-Sided Silicon Strip Detector Employing a Pulsed Proton Microbeam
Abstract:
Monoenergetic pulsed proton beams at energies of 1 and 3 MeV per proton have been employed to characterize a segmented double-sided silicon strip detector. The detector is manufactured from a neutron transmutation doped silicon wafer and features a bulk resistivity of . Signals from both P-side and N-side strips have been digitized at 14 b, 100 MS/s. The beam was focused either in the middle of one strip or on the gap in between two strips. Energy resolution, charge collection time, and interstrip effects (charge sharing, charge losses, and inverted polarity pulses) have been investigated at different bias voltages and for particles entering either from the junction side or from the ohmic side.
Autors: J. A. Dueñas;G. Pasquali;L. Acosta;T. Parsani;F. Riccio;L. Carraresi;F. Taccetti;A. Castoldi;C. Guazzoni;
Appeared in: IEEE Transactions on Nuclear Science
Publication date: Sep 2017, volume: 64, issue:9, pages: 2551 - 2560
Publisher: IEEE
 
» Characterization of Kerfless Linear Arrays Based on PZT Thick Film
Abstract:
Multielement transducers enabling novel cost-effective fabrication of imaging arrays for medical applications have been presented earlier. Due to the favorable low lateral coupling of the screen-printed PZT, the elements can be defined by the top electrode pattern only, leading to a kerfless design with low crosstalk between the elements. The thick-film-based linear arrays have proved to be compatible with a commercial ultrasonic scanner and to support linear array beamforming as well as phased array beamforming. The main objective of the presented work is to investigate the performance of the devices at the transducer level by extensive measurements of the test structures. The arrays have been characterized by several different measurement techniques. First, electrical impedance measurements on several elements in air and liquid have been conducted in order to support material parameter identification using the Krimholtz–Leedom–Matthaei model. It has been found that electromechanical coupling is at the level of 35%. The arrays have also been characterized by a pulse-echo system. The measured sensitivity is around −60 dB, and the fractional bandwidth is close to 60%, while the center frequency is about 12 MHz over the whole array. Finally, laser interferometry measurements have been conducted indicating very good displacement level as well as pressure. The in-depth characterization of the array structure has given insight into the performance parameters for the array based on PZT thick film, and the obtained information will be used to optimize the key parameters for the next generation of cost-effective arrays based on piezoelectric thick film.
Autors: Tomasz Zawada;Louise Møller Bierregaard;Erling Ringgaard;Ruichao Xu;Michele Guizzetti;Franck Levassort;Dominique Certon;
Appeared in: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Publication date: Sep 2017, volume: 64, issue:9, pages: 1409 - 1416
Publisher: IEEE
 
» Characterization of the Photon Counting CHASE Jr., Chip Built in a 40-nm CMOS Process With a Charge Sharing Correction Algorithm Using a Collimated X-Ray Beam
Abstract:
This paper presents the detailed characterization of a single photon counting chip, named CHASE Jr., built in a CMOS 40-nm process, operating with synchrotron radiation. The chip utilizes an on-chip implementation of the C8P1 algorithm. The algorithm eliminates the charge sharing related uncertainties, namely, the dependence of the number of registered photons on the discriminator’s threshold, set for monochromatic irradiation, and errors in the assignment of an event to a certain pixel. The article presents a short description of the algorithm as well as the architecture of the CHASE Jr., chip. The analog and digital functionalities, allowing for proper operation of the C8P1 algorithm are described, namely, an offset correction for two discriminators independently, two-stage gain correction, and different operation modes of the digital blocks. The results of tests of the C8P1 operation are presented for the chip bump bonded to a silicon sensor and exposed to the 3.5--wide pencil beam of 8-keV photons of synchrotron radiation. It was studied how sensitive the algorithm performance is to the chip settings, as well as the uniformity of parameters of the analog front-end blocks. Presented results prove that the C8P1 algorithm enables counting all photons hitting the detector in between readout channels and retrieving the actual photon energy.
Autors: A. Krzyżanowska;G. W. Deptuch;P. Maj;P. Gryboś;R. Szczygieł;
Appeared in: IEEE Transactions on Nuclear Science
Publication date: Sep 2017, volume: 64, issue:9, pages: 2561 - 2568
Publisher: IEEE
 
» Chemical and Electrical Dynamics of Polyimide Film Damaged by Electron Radiation
Abstract:
The processes of electrical charge accumulation and dissipation in dielectric materials are critical to spacecraft construction and operational anomaly resolution. Electrical conductivity, and therefore surface potential, of radiation-damaged materials undergoes unpredicted changes while on orbit. The space environment causes fundamental modifications in the chemical structure of spacecraft materials by breaking intermolecular bonds and creating free radicals that act as space charge traps. Over time, free radicals react with each other and the material recovers. The rates of free radical formation and loss determine the dynamics of the conductivity of spacecraft materials. Lack of knowledge about dynamic aging is a major impediment to accurate modeling of spacecraft behavior over its mission life. This paper presents an investigation of the chemical and physical properties of polyimide (PI) films during and after irradiation with high-energy (90 keV) electrons. The constant voltage method was utilized to monitor material conductivity during the recovery process. To quantify the concentration of free radicals within the irradiated material, the electron paramagnetic resonance technique was used. Changes in the infrared (IR) absorption profile of irradiated materials during the recovery process were identified using the directional-hemispherical reflectance technique coupled with the Fourier transform IR spectroscopy. This physical/chemical collaboration allowed correlation of chemical changes in PI with the dynamic nature of spacecraft material aging.
Autors: Daniel P. Engelhart;Elena Plis;Sunita Humagain;Steven Greenbaum;Dale Ferguson;Russell Cooper;Ryan Hoffmann;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Sep 2017, volume: 45, issue:9, pages: 2573 - 2577
Publisher: IEEE
 
» Chemical Sensing Strategies for Real-Time Monitoring of Transformer Oil: A Review
Abstract:
Power transformers are a central component in the field of energy distribution and transmission. The early recognition of incipient faults in operating transformers is substantially cost effective by lessening impromptu blackouts. A standout amongst the most responsive and dependable strategies utilized for assessing the health of oil filled electrical equipment is dissolved gas analysis (DGA). Nowadays, there is an expanding requirement for better nonintrusive diagnostic and online monitoring tools to survey the internal state of the transformers. Chemical sensors are viewed as a key innovation for condition monitoring of transformer health, coordinating the non-invasiveness with typical sensor features, such as cost, usability, portability, and the integration with the data networks. Low-cost chemical sensors-based DGA techniques are expected to drastically augment the diagnostic abilities empowering the deployment on a broader range of oil filled power assets. The recent development involves both specific sensors designed to detect individual dissolved gas in transformer oil and non-specific sensors, operated in near ambient conditions, with the potential to be applied in a DGA system. In this paper, general background and operating guidelines of DGA are presented to address the origin of the gas formation, methods for their detection and the interpretation of the results by data analytics. The recent significant interest and advancements in chemical sensors to DGA applications are reviewed. Future research perspectives and challenges for the development of novel DGA chemical sensors are also discussed.
Autors: Chenhu Sun;Paul R. Ohodnicki;Emma M. Stewart;
Appeared in: IEEE Sensors Journal
Publication date: Sep 2017, volume: 17, issue:18, pages: 5786 - 5806
Publisher: IEEE
 
» Circuit and System Designs of Ultra-Low Power Sensor Nodes With Illustration in a Miniaturized GNSS Logger for Position Tracking: Part I—Analog Circuit Techniques
Abstract:
This paper, split into Parts I and II, reviews recent innovations in circuit design that have accelerated the miniaturization of sensor nodes. Design techniques for key building blocks, such as sensor interfaces, timing reference, data communication, energy harvesting, and power management are reviewed. In particular, Part I introduces analog circuit techniques and sensor interfaces for miniaturized sensor nodes. The energy budget of such system is highly restricted due to the small battery volume. Therefore, ultra-low power design techniques are critical enablers and are reviewed. Design techniques for compact monolithic integration are also discussed.
Autors: Taekwang Jang;Gyouho Kim;Benjamin Kempke;Michael B. Henry;Nikolaos Chiotellis;Carl Pfeiffer;Dongkwun Kim;Yejoong Kim;Zhiyoong Foo;Hyeongseok Kim;Anthony Grbic;Dennis Sylvester;Hun-Seok Kim;David D. Wentzloff;David Blaauw;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Sep 2017, volume: 64, issue:9, pages: 2237 - 2249
Publisher: IEEE
 

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