Electrical and Electronics Engineering publications abstract of: 01-2017 sorted by title, page: 2

» Accurate Lungs Segmentation on CT Chest Images by Adaptive Appearance-Guided Shape Modeling
Abstract:
To accurately segment pathological and healthy lungs for reliable computer-aided disease diagnostics, a stack of chest CT scans is modeled as a sample of a spatially inhomogeneous joint 3D Markov-Gibbs random field (MGRF) of voxel-wise lung and chest CT image signals (intensities). The proposed learnable MGRF integrates two visual appearance sub-models with an adaptive lung shape submodel. The first-order appearance submodel accounts for both the original CT image and its Gaussian scale space (GSS) filtered version to specify local and global signal properties, respectively. Each empirical marginal probability distribution of signals is closely approximated with a linear combination of discrete Gaussians (LCDG), containing two positive dominant and multiple sign-alternate subordinate DGs. The approximation is separated into two LCDGs to describe individually the lungs and their background, i.e., all other chest tissues. The second-order appearance submodel quantifies conditional pairwise intensity dependencies in the nearest voxel 26-neighborhood in both the original and GSS-filtered images. The shape submodel is built for a set of training data and is adapted during segmentation using both the lung and chest appearances. The accuracy of the proposed segmentation framework is quantitatively assessed using two public databases (ISBI VESSEL12 challenge and MICCAI LOLA11 challenge) and our own database with, respectively, 20, 55, and 30 CT images of various lung pathologies acquired with different scanners and protocols. Quantitative assessment of our framework in terms of Dice similarity coefficients, 95-percentile bidirectional Hausdorff distances, and percentage volume differences confirms the high accuracy of our model on both our database (98.4±1.0%, 2.2±1.0 mm, 0.42±0.10%) and the VESSEL12 database (99.0±0.5±1.6 mm, 0.39±0.20%), respectively. Similarly, the accuracy of our approach is further verified via a blind evaluation by the organizers of the LOLA11 competition, where an average overlap of 98.0% with the expert’s segmentation is yielded on all 55 subjects with our framework being ranked first among all the state-of-the-art techniques compared.
Autors: Ahmed Soliman;Fahmi Khalifa;Ahmed Elnakib;Mohamed Abou El-Ghar;Neal Dunlap;Brian Wang;Georgy Gimel’farb;Robert Keynton;Ayman El-Baz;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Jan 2017, volume: 36, issue:1, pages: 263 - 276
Publisher: IEEE
 
» Accurate Reconstruction and Suppression for Azimuth Ambiguities in Spaceborne Stripmap SAR Images
Abstract:
In this letter, an accurate mathematical model for azimuth ambiguity in stripmap synthetic aperture radar (SAR) images is first constructed, with an azimuth ambiguity factor (AAF) defined as the residual amplitude and phase terms of ambiguities. Next, a novel framework for reconstructing and suppressing azimuth ambiguity is proposed based on the analysis of the AAF. In this framework, azimuth ambiguities are accurately reconstructed by applying reconstruction filters in the range Doppler and 2-D frequency domain, and then, the reconstructed signal is used for suppressing azimuth ambiguities. Moreover, the proposed framework does not depend on the statistical characteristics of a SAR image and is capable of reducing the space-variant ambiguities. As verified by both simulated data and real TerraSAR-X data, the proposed method is capable of suppressing azimuth ambiguities in SAR images.
Autors: Jie Chen;Kai Wang;Wei Yang;Wei Liu;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Jan 2017, volume: 14, issue:1, pages: 102 - 106
Publisher: IEEE
 
» Achievable Rates of Cognitive Radio Networks Using Multilayer Coding With Limited CSI
Abstract:
In a cognitive radio (CR) framework, the channel state information (CSI) feedback to the secondary transmitter (SU_Tx) can be limited or unavailable. Thus, the statistical model is adopted to determine system performance using the outage concept. In this paper, we adopt a new approach using multilayer-coding (MLC) strategy, i.e., broadcast approach, to enhance spectrum sharing over fading channels. First, we consider a scenario where the SU_Tx has no CSI of both the link between the SU_Tx and the primary receiver (cross link) and its own link. We show that using MLC improves the cognitive rate compared with the rate provided by a single-layer coding (SLC). In addition, we observe numerically that two-layer coding achieves most of the gain for Rayleigh fading. Second, we analyze a scenario where SU_Tx is provided by partial CSI about its link through quantized CSI. We compute its achievable rate, adopting the MLC and highlight the improvement over SLC. Finally, we study the case in which the cross link is perfect, i.e., a cooperative primary user setting, and compare the performance with the previous cases. We present asymptotic analysis at the high-power regime and show that the cooperation considerably enhances the cognitive rate at high values of the secondary power budget.
Autors: Lokman Sboui;Zouheir Rezki;Mohamed-Slim Alouini;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jan 2017, volume: 66, issue:1, pages: 395 - 405
Publisher: IEEE
 
» Achieving Economic Operation and Secondary Frequency Regulation Simultaneously Through Local Feedback Control
Abstract:
This paper presents an exciting finding for the power industry: The parameters of secondary frequency control based on integral or proportional integral control can be tuned to achieve economic operation and frequency regulation simultaneously within a considerable short period. We show that if the power imbalance is represented by frequency deviation, an iterative dual-ascent-based economic dispatch solving is equivalent to integral control. An iterative method of multipliers based economic dispatch is equivalent to proportional integral control. Similarly, if the controller parameters of the secondary frequency controls are chosen based on generator cost functions, these secondary frequency controllers achieve both economic operation and frequency regulation simultaneously.
Autors: Zhixin Miao;Lingling Fan;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jan 2017, volume: 32, issue:1, pages: 85 - 93
Publisher: IEEE
 
» Active Clustering with Model-Based Uncertainty Reduction
Abstract:
Semi-supervised clustering seeks to augment traditional clustering methods by incorporating side information provided via human expertise in order to increase the semantic meaningfulness of the resulting clusters. However, most current methods are passive in the sense that the side information is provided beforehand and selected randomly. This may require a large number of constraints, some of which could be redundant, unnecessary, or even detrimental to the clustering results. Thus in order to scale such semi-supervised algorithms to larger problems it is desirable to pursue an active clustering method—i.e., an algorithm that maximizes the effectiveness of the available human labor by only requesting human input where it will have the greatest impact. Here, we propose a novel online framework for active semi-supervised spectral clustering that selects pairwise constraints as clustering proceeds, based on the principle of uncertainty reduction. Using a first-order Taylor expansion, we decompose the expected uncertainty reduction problem into a gradient and a step-scale, computed via an application of matrix perturbation theory and cluster-assignment entropy, respectively. The resulting model is used to estimate the uncertainty reduction potential of each sample in the dataset. We then present the human user with pairwise queries with respect to only the best candidate sample. We evaluate our method using three different image datasets (faces, leaves and dogs), a set of common UCI machine learning datasets and a gene dataset. The results validate our decomposition formulation and show that our method is consistently superior to existing state-of-the-art techniques, as well as being robust to noise and to unknown numbers of clusters.
Autors: Caiming Xiong;David M. Johnson;Jason J. Corso;
Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence
Publication date: Jan 2017, volume: 39, issue:1, pages: 5 - 17
Publisher: IEEE
 
» Active–Passive $Delta Sigma $ Modulator for High-Resolution and Low-Power Applications
Abstract:
This paper discusses the use of a low gain amplifier and a passive switched-capacitor (SC) network to enable the SC integrator function. The method is applied to a delta-sigma modulator to achieve high resolution as proved by the 65-nm CMOS technology test vehicle. Compared with the conventional operational amplifier (op-amp)-based SC integrator, this solution utilizes a low-gain open-loop amplifier to drive a passive SC integrator with positive feedback. Since the open-loop amplifier requires a low dc gain and implements an embedded current adder, the power consumption is very low. Power reduction for single bit is obtained by using passive feedforward with built-in adder to assist the first amplifier. The low swing obtained at the output of the active blocks relaxes the slew rate requirement and enhances the linearity. Implemented in 65-nm digital CMOS technology with an active area of 0.1 mm2, the test chip achieves a dynamic range of 91 dB, peak signal-to-noise ratio of 88.4 dB, peak signal-to-noise-plus-distortion ratio of 88.2 dB, and a spurious free dynamic range of 106 dB while consuming 73.6 in a 25-kHz signal bandwidth at 1 V supply, yielding a FoMWalden of 70 fJ/conv-step and FoM of 176 dB.
Autors: Arshad Hussain;Sai-Weng Sin;Chi-Hang Chan;Seng-Pan Ben U;Franco Maloberti;Rui P. Martins;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Jan 2017, volume: 25, issue:1, pages: 364 - 374
Publisher: IEEE
 
» Ad Hoc and Sensor Networks
Abstract:
Autors: Edoardo Biagioni;Silvia Giordano;Ciprian Dobre;
Appeared in: IEEE Communications Magazine
Publication date: Jan 2017, volume: 55, issue:1, pages: 166 - 167
Publisher: IEEE
 
» Adaptive Actuator Failure Compensation for a Class of Nonlinear Systems With Unknown Control Direction
Abstract:
In this note, a novel adaptive compensation control scheme is proposed for a class of nonlinear systems with unknown control direction and a possibly infinite number of unknown actuator failures. By introducing a bound estimation approach, high-order Lyapunov functions and a Nussbaum function with faster growth rate, the obstacle caused by unknown failures and unknown control direction is successfully circumvented and all signals of the closed-loop system are proved to be globally uniformly bounded. Moreover, the proposed scheme is able to steer the tracking error into a predefined small residue set. Simulation results are presented to illustrate the effectiveness of the proposed scheme.
Autors: Chenliang Wang;Changyun Wen;Yan Lin;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Jan 2017, volume: 62, issue:1, pages: 385 - 392
Publisher: IEEE
 
» Adaptive Backstepping Control of Spacecraft Rendezvous and Proximity Operations With Input Saturation and Full-State Constraint
Abstract:
This paper presents a six-degree-of-freedom relative motion control method for autonomous spacecraft rendezvous and proximity operations subject to input saturation, full-state constraint, kinematic coupling, parametric uncertainty, and matched and mismatched disturbances. Relative rotational and relative translational controllers are developed separately based on a unified adaptive backstepping technique. Both element-wise and norm-wise adaptive estimation techniques are used for handling parametric uncertainties, kinematic couplings, and matched and mismatched disturbances, where the bounds of disturbances are unknown. Two auxiliary design systems are employed to deal with input saturation in the relative rotational and relative translational control designs, and the stability of the saturated control solution is verified. Full-state constraint of the relative pose motion is handled by using barrier Lyapunov functions while achieving a satisfactory control performance. All signals in the closed-loop system are guaranteed to be uniformly ultimately bounded, and the relative motion states are all restricted within the known constraints. Compared with the previous control designs of spacecraft rendezvous and proximity operations, the proposed control strategy in this paper can simultaneously deal with input saturation, full-state constraint, kinematic coupling, parametric uncertainty, and matched and mismatched disturbances. Experimental simulation results validate the performance and robustness improvement of the proposed control strategy.
Autors: Liang Sun;Wei Huo;Zongxia Jiao;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Jan 2017, volume: 64, issue:1, pages: 480 - 492
Publisher: IEEE
 
» Adaptive Beacon Transmission in Cognitive-OFDM-Based Industrial Wireless Networks
Abstract:
Wireless interferences from heterogeneous networks in the crowded industrial scientific medical band set up technical barriers for reliable communication of industrial wireless network (IWN). In this letter, an adaptive beacon transmission strategy is proposed for dynamically scheduling the cognitive-OFDM IWN to avoid channel interferences without using a dedicated control channel. Preambles of beacons are specifically designed in the PHY layer to embed specific information. A generalized likelihood ratio test (GLRT)-based approach is applied to detect the beacon transmission and a maximum likelihood estimator is employed to estimate the beacon information embedded in the preamble. The performance of the GLRT approach to detect the adaptive beacon transmission is evaluated through simulations and practical experiments. The detection and decoding accuracies of the proposed adaptive beacon transmission are close to 100% with reasonable signal-to-noise ratio even under interference.
Autors: Lian Li;Cailian Chen;Yiyin Wang;Tian He;Xinping Guan;
Appeared in: IEEE Communications Letters
Publication date: Jan 2017, volume: 21, issue:1, pages: 152 - 155
Publisher: IEEE
 
» Adaptive Blind Postdistortion and Equalization of System Impairments for a Single-Channel Concurrent Dual-Band Receiver
Abstract:
Concurrent dual-band receivers use fewer RF components to flexibly receive signals in the dual bands. To further reduce the number of components, a compact concurrent dual-band receiver architecture has been demonstrated in this paper. It employs only a single down-conversion channel to down-convert the dual-band signals simultaneously. The down-converted signal is a relatively narrowband signal without the wide gap between the two bands. Hence, slower analog-to-digital converters can be adopted in the subsequent circuits to digitize the received signal. Due to the nonlinearity of the low-noise amplifier, there might be noticeable nonlinearity distortion and memory effects in the received dual-band signals. To ensure high signal quality, a blind postdistortion algorithm is proposed to cancel out the nonlinearity distortion in the two received signals adaptively. Subsequently, the blind finite-impulse response equalizers for each band are built based on the modified constant modulus algorithm and the decision-directed equalization method. In addition, the nonideal wireless channel response is also able to be compensated using the proposed algorithm. Experimental results have shown perfect postcompensation performances of the overall algorithms in the dual bands.
Autors: Youjiang Liu;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Jan 2017, volume: 65, issue:1, pages: 302 - 314
Publisher: IEEE
 
» Adaptive Control for a Class of Uncertain Nonlinear Systems: Application to Photovoltaic Control Systems
Abstract:
In this technical note, an adaptive control framework for compensation of uncertainties and perturbations that satisfy the matching condition on a class of nonlinear dynamic systems is presented. The proposed method does not need the explicit knowledge of the bound values on the uncertainties, and the resulting compensatory term is continuous. The application of this formulation for maximum power point tracking and unity power factor on grid-connected photovoltaic systems is presented.
Autors: Fernando Jaramillo-Lopez;Godpromesse Kenne;Francoise Lamnabhi-Lagarrigue;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Jan 2017, volume: 62, issue:1, pages: 393 - 398
Publisher: IEEE
 
» Adaptive Fault-Tolerant PI Tracking Control With Guaranteed Transient and Steady-State Performance
Abstract:
It is a long lasting open problem to synthesize a general PI control for nonlinear systems with its gains analytically determined, yet ensuring stability and transient performance. The problem is further complicated if modeling uncertainties and external disturbances as well as actuation failures are involved in the systems. In this note, a generalized PI control with adaptively adjusting gains is presented, which gracefully avoids the adhoc and time-consuming “trial and error” process for determining the gains as involved in traditional PI control; collectively accommodates modeling uncertainties, undetectable disturbances and undetectable actuation failures that might occur in the systems; and dynamically maintains pre-specified transient and steady-state performance.
Autors: Yongduan Song;Yujuan Wang;Changyun Wen;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Jan 2017, volume: 62, issue:1, pages: 481 - 487
Publisher: IEEE
 
» Adaptive Fault-Tolerant Tracking Control for MIMO Discrete-Time Systems via Reinforcement Learning Algorithm With Less Learning Parameters
Abstract:
This paper is concerned with a reinforcement learning-based adaptive tracking control technique to tolerate faults for a class of unknown multiple-input multiple-output nonlinear discrete-time systems with less learning parameters. Not only abrupt faults are considered, but also incipient faults are taken into account. Based on the approximation ability of neural networks, action network and critic network are proposed to approximate the optimal signal and to generate the novel cost function, respectively. The remarkable feature of the proposed method is that it can reduce the cost in the procedure of tolerating fault and can decrease the number of learning parameters and thus reduce the computational burden. Stability analysis is given to ensure the uniform boundedness of adaptive control signals and tracking errors. Finally, three simulations are used to show the effectiveness of the present strategy.
Autors: Lei Liu;Zhanshan Wang;Huaguang Zhang;
Appeared in: IEEE Transactions on Automation Science and Engineering
Publication date: Jan 2017, volume: 14, issue:1, pages: 299 - 313
Publisher: IEEE
 
» Adaptive Robust Network-Constrained AC Unit Commitment
Abstract:
This paper presents an adaptive robust network-constrained AC unit commitment (AC-UC) model. This model is formulated as a min–max–min optimization problem, which allows representing the uncertain nature of wind power productions in terms of bounded intervals. A tri-level decomposition algorithm using primal and dual cutting planes is introduced to solve this AC-UC problem and to find a robust commitment schedule withstanding the worst realizations of uncertain wind power. To reduce the computation burden and to obtain a tractable formulation, the AC power flow equations are convexified using a Signomial transformation. The proposed AC-UC model is illustrated using the IEEE 24-bus reliability test system. Simulation results demonstrate the efficiency of the proposed approach.
Autors: Nima Amjady;Shahab Dehghan;Ahmad Attarha;Antonio J. Conejo;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jan 2017, volume: 32, issue:1, pages: 672 - 683
Publisher: IEEE
 
» Adaptive Search Algorithms for Discrete Stochastic Optimization: A Smooth Best-Response Approach
Abstract:
This paper considers simulation-based optimization of the performance of a regime-switching stochastic system over a finite set of feasible configurations. Inspired by the stochastic fictitious play learning rules in game theory, we propose an adaptive random search algorithm that uses a smooth best-response sampling strategy and tracks the set of global optima, yet distributes the search so that most of the effort is spent on simulating the system performance at the global optima. The algorithm responds properly to the random unpredictable jumps of the global optimum even when the observations data are temporally correlated as long as a weak law of large numbers holds. Numerical examples show that the proposed scheme yields faster convergence and superior efficiency for finite sample lengths compared with several existing random search and pure exploration methods in the literature.
Autors: Omid Namvar Gharehshiran;Vikram Krishnamurthy;George Yin;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Jan 2017, volume: 62, issue:1, pages: 161 - 176
Publisher: IEEE
 
» Adaptive Simulation Model of a Double-Pressure Heat Recovery Steam Generator for Current Optimization in Control Systems
Abstract:
Control is the conscious impact on a process in order to realize specific goals. When controlling complex industry processes, the most frequent control method is based on a layered structure (hierarchical), which includes a layer of regulation and protection and a layer of optimization. The optimization layer is used to identify the most cost-effective levels for the regulation layer. This includes the use of process static models that must be structurally simple and quick at calculating, while maintaining a high level of accuracy. The most frequent method of model designing involves experimental analysis called process identification. However, we can develop models that result from the laws of physics with additional use of empirical relationships. This article presents a simulation model of a double-pressure heat recovery steam generator (HRSG) in gas turbine combined cycle power plant. The model was developed based on the equations of mass and energy balances and the empirical relationships describing the process of heat transfer and pressure drop of working fluid in the heat exchanger. Unknown values of empirical coefficients were estimated based on the operating data with the least-squares method. The model allows the calculation of nonmeasured operating parameters and energy assessment indicators. An important benefit of the developed model is that it has the capability of adapting to the changing technical conditions of the HRSG. The results of calculations were compared to the results of measurements. Model predictive quality was verified with the use of the determination factor and root mean square error.
Autors: Marcin Plis;Henryk Rusinowski;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Jan 2017, volume: 53, issue:1, pages: 530 - 537
Publisher: IEEE
 
» Adaptive Visual Tracking with Minimum Uncertainty Gap Estimation
Abstract:
A novel tracking algorithm is proposed, which robustly tracks a target by finding the state that minimizes the likelihood uncertainty. Likelihood uncertainty is estimated by determining the gap between the lower and upper bounds of likelihood. By minimizing the gap between the two bounds, the proposed method identifies the confident and reliable state of the target. In this study, the state that provides the Minimum Uncertainty Gap (MUG) between likelihood bounds is shown to be more reliable than the state that provides the maximum likelihood only, especially when severe illumination changes, occlusions, and pose variations occur. A rigorous derivation of the lower and upper bounds of the likelihood for the visual tracking problem is provided to address this issue. Additionally, an efficient inference algorithm that uses Interacting Markov Chain Monte Carlo (IMCMC) approach is presented to find the best state that maximizes the average of the lower and upper bounds of likelihood while minimizing the gap between the two bounds. We extend our method to update the target model adaptively. To update the model, the current observation is combined with a previous target model with the adaptive weight, which is calculated according to the goodness of the current observation. The goodness of the observation is measured using the proposed uncertainty gap estimation of likelihood. Experimental results demonstrate that the proposed method robustly tracks the target in realistic videos and outperforms conventional tracking methods.
Autors: Junseok Kwon;Kyoung Mu Lee;
Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence
Publication date: Jan 2017, volume: 39, issue:1, pages: 18 - 31
Publisher: IEEE
 
» Adaptive Voltage Control for Bidirectional Converter in Flicker-Free Electrolytic Capacitor-Less AC–DC LED Driver
Abstract:
In this paper, an electrolytic capacitor-less ac–dc light-emitting diode (LED) driver, consisting of a power factor correction (PFC) converter and a buck/boost bidirectional converter, is investigated. The buck/boost bidirectional converter is connected in parallel with the output of the PFC converter and serves to absorb the second harmonic current in the PFC output current, leaving only a dc component to drive the LEDs. This paper proposes an adaptive voltage control scheme for the storage capacitor in the buck/boost bidirectional converter to make the storage capacitor voltage adaptively decrease as the load becomes lighter. Hence, the power losses of the buck/boost bidirectional converter could be reduced at light load. Experimental results are provided to verify the effectiveness of the proposed control scheme.
Autors: Jiexiu He;Xinbo Ruan;Li Zhang;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Jan 2017, volume: 64, issue:1, pages: 320 - 324
Publisher: IEEE
 
» Additive Rank Metric Codes
Abstract:
We give an infinite family of maximum rank distance (MRD) codes, which covers properly the largest known linear MRD code family. Our family contains infinite families of non-linear MRD codes, which are the first non-linear examples for most of the parameters. We also give explicit examples and a table that demonstrates the proportion of linear and non-linear families for some small parameters.
Autors: Kamil Otal;Ferruh Özbudak;
Appeared in: IEEE Transactions on Information Theory
Publication date: Jan 2017, volume: 63, issue:1, pages: 164 - 168
Publisher: IEEE
 
» Advanced Blanking Nonlinearity for Mitigating Impulsive Interference in OFDM Systems
Abstract:
In this paper, we introduce advancements of the conventional blanking nonlinearity (BN) for orthogonal frequency-division multiplexing (OFDM)-based systems, which is referred to in the following as advanced BN. Blanking is a common measure for mitigating impulsive interference that often occurs in wireless communication systems. Although the BN removes impulsive interference reliably, it possesses various drawbacks for OFDM-based systems. In particular, the choice of the blanking threshold (BT), to decide whether a received sample is blanked, is a critical issue. We present an algorithm for determining the optimal BT to maximize the signal-to-noise-and-interference ratio (SINR) after blanking. Another drawback is that the entire received signal is discarded during a blanking interval, despite the fact that only a fraction of the spectrum of the OFDM signal might be affected by interference. We show how blanking can be limited to subcarriers that are actually affected by interference. Further, we show how these measures can be combined and how a priori information obtained in an iterative loop can be incorporated into the proposed scheme. Simulation results incorporating realistic channel and interference models demonstrate the effectiveness of the proposed scheme.
Autors: Ulrich Epple;Michael Schnell;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jan 2017, volume: 66, issue:1, pages: 146 - 158
Publisher: IEEE
 
» Advanced Generator Ground Fault Protections in Pulp and Paper Mill Applications
Abstract:
Ground faults in field/rotor and generator stator circuits are serious events that can lead to damage, costly repair, extended outages, and loss of revenue. This paper explores advances in field/rotor circuit ground fault and stator ground fault protection. These advanced protection strategies employ ac injection, ground differential protection, and the use of hybrid grounding to reduce both internal generator ground fault levels and facility ground levels in utility-paralleled operating modes.
Autors: Wayne Hartmann;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Jan 2017, volume: 53, issue:1, pages: 745 - 750
Publisher: IEEE
 
» Advanced Methods for Tabulation of Electrical Loads During Special Modes of Marine Vessel Operation
Abstract:
Current shipbuilding standards allow designers to utilize traditional legacy methods for calculation of electrical load totals during typical shipboard evolutions by applying load factors based on percent time in operation. The time has come to consider mandating more intelligent techniques of calculating load totals on vessels with electric propulsion systems. For electric propulsion vessels with special operating profiles, using the traditional methods to attempt to calculate loading on components such as bidirectional zonal power sources/loads simply does not work. For vessels with large variable electric loads, such as electric propulsion, the electric power load analysis should be done using stochastic methods for special modes of operation, such as dynamic positioning, roll-on/roll-off operations, or offshore petroleum discharge mode. This paper will examine the issue from the perspective of a ship designer and will provide examples of how to apply more advanced techniques for performing load analyses on ships with electrical propulsion systems. Proposed changes to classification society rules and other marine standards will be recommended.
Autors: James Wolfe;Michael J. Roa;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Jan 2017, volume: 53, issue:1, pages: 667 - 674
Publisher: IEEE
 
» Advanced Technologies for Brain Research [Scanning the Issue]
Abstract:
We believe that this special issue will serve to increase the public awareness and foster discussions on the multiple worldwide BRAIN initiatives, both within and outside the IEEE, providing an impetus for development of long-term cost-effective healthcare solutions. We also believe that the topics presented in this special issue will serve as scientific evidence for health and policy advocates of the value of neurotechnologies for improving the neurological and mental health and wellbeing of the general population. Below we briefly highlight the papers and technologies in this special issue.
Autors: Metin Akay;Paul Sajda;Silvestro Micera;Jose M. Carmena;
Appeared in: Proceedings of the IEEE
Publication date: Jan 2017, volume: 105, issue:1, pages: 8 - 10
Publisher: IEEE
 
» Advances in Two-Photon Scanning and Scanless Microscopy Technologies for Functional Neural Circuit Imaging
Abstract:
Recent years have seen substantial developments in technology for imaging neural circuits, raising the prospect of large-scale imaging studies of neural populations involved in information processing, with the potential to lead to step changes in our understanding of brain function and dysfunction. In this paper, we will review some key recent advances: improved fluorophores for single-cell resolution functional neuroimaging using a two-photon microscope; improved approaches to the problem of scanning active circuits; and the prospect of scanless microscopes which overcome some of the bandwidth limitations of current imaging techniques. These advances in technology for experimental neuroscience have in themselves led to technical challenges, such as the need for the development of novel signal processing and data analysis tools in order to make the most of the new experimental tools. We review recent work in some active topics, such as region of interest segmentation algorithms capable of demixing overlapping signals, and new highly accurate algorithms for calcium transient detection. These advances motivate the development of new data analysis tools capable of dealing with spatial or spatiotemporal patterns of neural activity that scale well with pattern size.
Autors: Simon R. Schultz;Caroline S. Copeland;Amanda J. Foust;Peter Quicke;Renaud Schuck;
Appeared in: Proceedings of the IEEE
Publication date: Jan 2017, volume: 105, issue:1, pages: 139 - 157
Publisher: IEEE
 
» AF Relaying With Energy Harvesting Source and Relay
Abstract:
In conventional energy harvesting amplify-and-forward relaying, only the relay harvests energy from the source. In this paper, a new energy harvesting relaying protocol is proposed, where the source also harvests energy from the relay, in addition to the energy harvesting relay. The performances of the new protocols using two different strategies are analyzed. Numerical results show that the new protocols have certain gain over the conventional protocol.
Autors: Yunfei Chen;Rui Shi;Wei Feng;Ning Ge;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jan 2017, volume: 66, issue:1, pages: 874 - 879
Publisher: IEEE
 
» AFLAS: An Adaptive Frame Length Aggregation Scheme for Vehicular Networks
Abstract:
Vehicular ad hoc networks (VANETs) experience large-scale high-speed mobility and volatile topology. VANETs may therefore experience intermittent connections and may occasionally be unable to guarantee end-to-end connections. This gives the medium access control (MAC) layer the opportunity to adapt its transmission strategy to the current unstable wireless connections to improve transmission efficiency. In this paper, we propose an adaptive frame length aggregation scheme (AFLAS) for VANETs, which is designed to improve transmission efficiency and increase data throughput. In our scheme, the incoming data packets from higher layers are queued separately in the MAC layer to wait for transmission opportunities. Suitable aggregation frame lengths are calculated according to the current wireless status and applied in the MAC layer at the onset of data transmissions. In this paper, we analyze and apply our AFLAS strategy to two current frame aggregation schemes in IEEE 802.11. We also report on the performance evaluation of our scheme. Our results exhibit significant improvement results in data throughput, retransmissions, overheads, and transmission efficiency in comparison with nonadaptive aggregation schemes.
Autors: Xiaoli Zhou;Azzedine Boukerche;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jan 2017, volume: 66, issue:1, pages: 855 - 867
Publisher: IEEE
 
» Aggregated Packet Transmission in Duty-Cycled WSNs: Modeling and Performance Evaluation
Abstract:
Duty cycling (DC) is a popular technique for energy conservation in wireless sensor networks (WSNs) that allows nodes to wake up and sleep periodically. Typically, a single-packet transmission (SPT) occurs per cycle, leading to possibly long delay. With aggregated packet transmission (APT), nodes transmit a batch of packets in a single cycle. The potential benefits brought by an APT scheme include shorter delay, higher throughput, and higher energy efficiency. In the literature, different analytical models have been proposed to evaluate the performance of SPT schemes. However, no analytical models for the APT mode on synchronous DC medium access control (MAC) mechanisms exist. In this paper, we first develop a 3-D discrete-time Markov chain (DTMC) model to evaluate the performance of an APT scheme with packet retransmission enabled. The proposed model captures the dynamics of the state of the queue of nodes and the retransmission status and the evolution of the number of active nodes in the network, i.e., nodes with a nonempty queue. We then study the number of retransmissions needed to transmit a packet successfully. Based on the observations, we develop another less-complex DTMC model with infinite retransmissions, which embodies only two dimensions. Furthermore, we extend the 3-D model into a 4-D model by considering error-prone channel conditions. The proposed models are adopted to determine packet delay, throughput, packet loss, energy consumption, and energy efficiency. Furthermore, the analytical models are validated through discrete-event-based simulations. Numerical results show that an APT scheme achieves substantially better performance than its SPT counterpart in terms of delay, throughput, packet loss, and energy efficiency and that the developed analytical models reveal precisely the behavior of the APT scheme.
Autors: Lakshmikanth Guntupalli;Jorge Martinez-Bauset;Frank Y. Li;Mary Ann Weitnauer;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jan 2017, volume: 66, issue:1, pages: 563 - 579
Publisher: IEEE
 
» Aging Precursor Identification and Lifetime Estimation for Thermally Aged Discrete Package Silicon Power Switches
Abstract:
Thermal/power cycles are widely acknowledged methods to accelerate the package related failures. Many studies have focused on one particular aging precursor at a time and continuously monitored it using custom-built circuits. Due to the difficulties in taking sensitive measurements, the reported findings are more on the quantities requiring less sensitive measurements. In this paper, two custom-designed testbeds are used to age a number of power MOSFETs and insulated gate bipolar transistors. An automated curve tracer is utilized to capture parametric variations in IV curves, parasitic capacitances, and gate charges at certain time intervals. The results suggest that the only viable aging precursors are the on-state voltage drop/on-state resistance, body diode voltage drop, parasitic capacitances, and gate threshold voltage for die attach solder and gate-oxide degradation mechanisms. Based on the experimental results, gate threshold voltage variation is empirically modeled to estimate the remaining useful lifetime of the switches experiencing gate oxide degradation. The model parameters are found by the least squares method applied to inliers determined by the random sample and consensus outlier removal algorithm.
Autors: Serkan Dusmez;Syed Huzaif Ali;Mehrdad Heydarzadeh;Anant S. Kamath;Hamit Duran;Bilal Akin;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Jan 2017, volume: 53, issue:1, pages: 251 - 260
Publisher: IEEE
 
» Air traffic control for delivery drones [Top Tech 2017]
Abstract:
In 2013, shortly before Christmas, Amazon.com released a video depicting its plans to speed packages to their destinations using small drones. Some commentators said it was just a publicity stunt. But the notion began to seem less far-fetched when Google revealed its own drone-based delivery effort in 2014, something it calls Project Wing. And in the early months of 2016, DHL actually integrated drones into its logistics network, albeit in an extremely limited way-delivering packages to a single mountaintop in Germany that is difficult to access by car in winter.
Autors: David Schneider;
Appeared in: IEEE Spectrum
Publication date: Jan 2017, volume: 54, issue:1, pages: 32 - 33
Publisher: IEEE
 
» Air–Ground Channel Characterization for Unmanned Aircraft Systems—Part I: Methods, Measurements, and Models for Over-Water Settings
Abstract:
The use of unmanned aerial systems (UASs), which are also known as unmanned aerial vehicles, and by the term “drones” in the popular press, is growing rapidly. To ensure safety, UAS control and nonpayload communication (CNPC) links must operate very reliably in a variety of conditions. This requires an accurate quantitative characterization of the air–ground (AG) channel, and this channel characterization is the focus of this paper. After providing motivation and background, we describe our methods and modeling approach, followed by a description of our simultaneous dual-band (L-band ∼970 MHz, C-band ∼5 GHz) measurement campaign and the over-water (OW) measurement sites. Example results for path loss and root-mean-square delay spread are provided, as well as the results for channel stationarity distance (SD), used in calculating small-scale Rician - factor and correlations between the two receiver antennas that we employed in each frequency band. Two distinct SD measures—the power delay profile (PDP) correlation coefficient and the spatial autocorrelation matrix collinearity—were used and found to be of the same order. Path-loss exponents are near that of free space, but significant two-ray cancelation effects for these OW settings warrant more accurate models, which we provide. Delay spreads in the OW channels are also dominated by the two-ray components and are hence typically very small (∼10 ns) but can exceed 350 ns. A third intermittent multipath component (MPC) is also present a nonnegligible fraction of time; hence, we provide statistical wideband AG channel models to represent this. Future papers in this series will report results for the AG channel with ground sites in other types of environments.
Autors: David W. Matolak;Ruoyu Sun;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jan 2017, volume: 66, issue:1, pages: 26 - 44
Publisher: IEEE
 
» Airplane Recognition in TerraSAR-X Images via Scatter Cluster Extraction and Reweighted Sparse Representation
Abstract:
Target recognition in synthetic aperture radar (SAR) images has become a hotspot in recent years. The backscattering characteristic of target is a significant issue taken into consideration in SAR applications. Almost all of the previous work focus on the scatter point extraction to depict the backscattering characteristic of the target; however, a point-target corresponds to a region rather than a single point due to the convolution during the imaging. Based on this fact, we first analyze the extent to how a point-target spreads, then propose a novel scatter cluster extraction (SCE) method, and utilize the scatter cluster as the feature to solve the airplane recognition problem in SAR images. In practice, there often exist interfering objects near the target to be classified. To overcome this issue, we design a reweighted sparse representation (RSR)-based automatic purifying method by assigning a weight to each element of the feature iteratively according to the representation error. Since the element with large representation error always corresponds to the interfering objects, we give it a small weight, consequently suppressing the influence of the interference. Experimental results demonstrate that the proposed SCE method outperforms the traditional scatter point extraction-based method as well as some state-of-the-art methods. The comparison result also validates the effectiveness of the proposed RSR method.
Autors: Zongxu Pan;Xiaolan Qiu;Zhongling Huang;Bin Lei;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Jan 2017, volume: 14, issue:1, pages: 112 - 116
Publisher: IEEE
 
» Algorithm Animation with Galant
Abstract:
Although surveys suggest positive student attitudes toward the use of algorithm animations, it is not clear that they improve learning outcomes. The Graph Algorithm Animation Tool, or Galant, challenges and motivates students to engage more deeply with algorithm concepts, without distracting them with programming language details or GUIs. Even though Galant is specifically designed for graph algorithms, it has also been used to animate other algorithms, most notably sorting algorithms.
Autors: Matthias F. Stallmann;
Appeared in: IEEE Computer Graphics and Applications
Publication date: Jan 2017, volume: 37, issue:1, pages: 8 - 14
Publisher: IEEE
 
» Aligning Requirements and Testing: Working Together toward the Same Goal
Abstract:
The proper alignment of requirements engineering and testing (RET) can be key to software's success. Three practices can provide effective RET alignment: using test cases as requirements, harvesting trace links, and reducing distances between requirements engineers and testers. The Web extra https://youtu.be/M65ZKxfxqME is an audio podcast of author Elizabeth Bjarnason reading the the Requirements column she cowrote with Markus Borg.
Autors: Elizabeth Bjarnason;Markus Borg;
Appeared in: IEEE Software
Publication date: Jan 2017, volume: 34, issue:1, pages: 20 - 23
Publisher: IEEE
 
» All-Fiber Fused Coupler for Stable Generation of Radially and Azimuthally Polarized Beams
Abstract:
The stable generation of TE01 and TM01 beams is demonstrated through a novel all-fiber fused coupler fabricated from a standard single mode fiber (SMF) and a custom air-core fiber. The fundamental mode in the SMF is directly coupled to the TM01 or TE01 mode by appropriately phase matching the modes in the fibers resulting in efficiency of ~67% and ~85%, and polarization purity of 70% and 82%, respectively. The phase matching is achieved through pre-tapering the SMF with precise control of the tapering ratio. The air-core fiber ensures selective excitation of the desired modes, thereby improving propagation stability and polarization quality of the TE01 and TM01 beams.
Autors: Shankar Pidishety;Balaji Srinivasan;Gilberto Brambilla;
Appeared in: IEEE Photonics Technology Letters
Publication date: Jan 2017, volume: 29, issue:1, pages: 31 - 34
Publisher: IEEE
 
» AlN/BP Heterostructure Photocatalyst for Water Splitting
Abstract:
In this letter, the structural, electronic, and optical properties of blue phosphorene (BP) and graphene-like aluminum nitride (AlN) nanocomposite are investigated by the first-principles method. Despite the indirect bandgap nature of the BP and AlN monolayers, AlN/BP heterostructure exhibits a direct bandgap characteristic in the most stable pattern. Moreover, we also find that the optically active states of the maximum valence and the minimum conduction bands are localized on opposite monolayers, leading to the electrons and holes spontaneously separated (type-II band alignment), which enhances the photocatalytic efficiency. Most interestingly, the AlN/BP heterobilayer exhibits enhanced optical properties in the visible and UV light zone, which is comparable or even superior to pristine BP—overall, the suitable direct gap and band edges positions, type-II band alignment, and fascinating visible and UV light adsorption, which enable AlN/BP heterostructure to have great potential applications in the field of solar energy conversion and photocatalytic water splitting.
Autors: Qun Yang;Chun-Jian Tan;Rui-Shen Meng;Jun-Ke Jiang;Qiu-Hua Liang;Xiang Sun;Dao-Guo Yang;Xian-Ping Chen;
Appeared in: IEEE Electron Device Letters
Publication date: Jan 2017, volume: 38, issue:1, pages: 145 - 148
Publisher: IEEE
 
» Amplification of Single Mechanical Fault Signatures Using Full Adaptive PMSM Observer
Abstract:
This paper presents a localized mechanical fault detection method using a full adaptive permanent-magnet synchronous machine (PMSM) observer in a d/q reference frame. It appears that the fault sensitivity of PMSM stator currents and rotor speed measurements is very low with regard to single mechanical faults. That is why an amplification of single mechanical fault signatures in frequency domain is proposed by adjusting the adaptive PMSM observer gains. To study the influence of the adaptive PMSM observer gains on fault signatures, the observer model is first of all linearized at an operating point. Then, the static gain, the resonance, and the quality factor Q of different transfer functions are analyzed. A dedicated experimental setup based on an original mechanical fault emulator and a 7.8 kW PMSM drive is designed to validate the simulation results. The simulation and the experimental results show that the proposed method is effective to amplify single mechanical fault signatures and the calculated fault indicator.
Autors: Mohamed Lamine Masmoudi;Erik Etien;Sandrine Moreau;Anas Sakout;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Jan 2017, volume: 64, issue:1, pages: 615 - 623
Publisher: IEEE
 
» An 8K H.265/HEVC Video Decoder Chip With a New System Pipeline Design
Abstract:
8K ultra-HD is being promoted as the next-generation video specification. While the High Efficiency Video Coding (HEVC) standard greatly enhances the feasibility of 8K with a doubled compression ratio, its implementation is a challenge, owing to ultrahigh-throughput requirements and increased complexity per pixel. The latter comes from the new features of HEVC. At the system level, the most challenging of them is the enlarged and highly variable-size coding/prediction/transform units, which significantly increase the requirement for on-chip memory as pipeline buffers and the difficulty in maintaining pipeline utilization. This paper presents an HEVC decoder chip featuring a system pipeline that works at a nonunified and variable granularity. The pipeline saves on-chip memory with a novel block-in-block-out queue system and a parameter delivery network, while allowing overhead-free and fully pipelined operation of the processing components. With the system pipeline design combined with various component-level optimizations, the proposed decoder in 40 nm achieves a maximum throughput of 4 Gpixels/s or 8K 120 frames/s for the low-delay-P configuration of HEVC, 7.5–55 times faster than prior works. It supports 8K 60 frames/s for the low-delay and random-access configurations. In a normalized comparison, it also shows 3.1–3.6 times better area efficiency and 31%–55% superior energy efficiency.
Autors: Dajiang Zhou;Shihao Wang;Heming Sun;Jianbin Zhou;Jiayi Zhu;Yijin Zhao;Jinjia Zhou;Shuping Zhang;Shinji Kimura;Takeshi Yoshimura;Satoshi Goto;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Jan 2017, volume: 52, issue:1, pages: 113 - 126
Publisher: IEEE
 
» An Accurate and Stable Sliding DFT Computed by a Modified CIC Filter [Tips & Tricks]
Abstract:
The sliding discrete Fourier transform (SDFT) is a popular algorithm used in nonparametric spectrum estimation when only a few frequency bins of an M-point discrete Fourier transform (DFT) are of interest. Although the classical SDFT algorithm described in [1] is computationally efficient, its recursive structure suffers from accumulation and rounding errors, which lead to potential instabilities or inaccurate output. Duda [2] proposed a modulated SDFT (mSDFT) algorithm, which has the property of being guaranteed stable without sacrificing accuracy, unlike previous approaches described in [1], [3], and [4]. However, all of these conventional SDFT methods presume DFT computation on a sample-by-sample basis. This is not computationally efficient when the DFT needs only to be computed every R(R > 1) samples. To address such cases when R-times downsampling is needed, Park et al. [5] proposed a hopping SDFT (HDFT) algorithm. Recently, Wang et al. [6] presented a modulated HDFT (mHDFT) algorithm, which combines the HDFT algorithm with the mSDFT idea to maintain stability and accuracy at the same time. In parallel, Park [7] updated the HDFT algorithm with its guaranteed stable modification called gSDFT, which exists only for certain M and L relationships.
Autors: Denis A. Gudovskiy;Lichung Chu;
Appeared in: IEEE Signal Processing Magazine
Publication date: Jan 2017, volume: 34, issue:1, pages: 89 - 93
Publisher: IEEE
 
» An Accurate Circuit Model for Input Impedance and Radiation Pattern of Two-Port Loop Antennas as E- and H-Probe
Abstract:
In this paper, a simple but very accurate circuit model for two-port (split) loop antennas typically used for direction finding in the HF-band is presented. The circuit model consists of lumped elements and can be used to accurately estimate the input impedances and received voltages of two-port loop antennas in receive mode. It is shown that the same circuit model can be reduced to predict the input impedance behavior of a single-port loop antenna with much more accuracy than the existing transmission line and lumped element models over a wide frequency range. The model is shown to be valid for frequencies up to a point where the loop circumference is about a wavelength. The same circuit model in receiving mode can provide the 3-D radiation pattern of the antenna.
Autors: Mani Kashanianfard;Kamal Sarabandi;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Jan 2017, volume: 65, issue:1, pages: 114 - 120
Publisher: IEEE
 
» An Accurate Fault Location Method for Multi-Circuit Series Compensated Transmission Lines
Abstract:
This paper presents a fault location method for multi-circuit series compensated line using phasor data from intelligent electronic devices available at both ends. In case of unavailability of synchronized data, analytical synchronization is obtained using an operator. In the formulation, the method considers untransposed line sections resulting on two sides of the fault and the distributed nature of line. For a healthy phase, currents on two sides at the fault point are equal unlike different currents on two sides in a faulted phase. This is checked over the line length and the fault location is pinpointed. The method does not require the model of the series compensation placed at any location on the line and can be used for both inter- and intra-circuit faults. It also considers reactive component of the fault impedance for accurate fault location. The method is tested using PSCAD/EMTDC simulations for a multi-circuit series-compensated line in Indian power grid. Evaluation study confirms the validity of the method for various faults.
Autors: Swaroop Gajare;Ashok Kumar Pradhan;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jan 2017, volume: 32, issue:1, pages: 572 - 580
Publisher: IEEE
 
» An Acoustic Communication Time Delays Compensation Approach for Master–Slave AUV Cooperative Navigation
Abstract:
Time delay is a major problem in the acoustic communication technology. Considering such a background, a new dynamic model is proposed for an improved error estimation algorithm in this paper. And error propagation equations are constructed for an inertial navigation system/Doppler velocity log integrated navigation system. The time delay problem is reconsidered for acoustic communication with an ultra-short baseline acoustic positioning system that uses a multi-autonomous underwater vehicle (AUV) cooperative navigation process in master–slave mode. The characteristics of time delays in acoustic communication are considered and the time delay is converted into a measurement bias within an observation equation for the slave AUV platform. Under the framework of a standard Kalman filter, an improved error estimation algorithm is presented to address the problem that occurs when random measurement bias exists in the dynamic linear system model. Based on the Monte Carlo method, the simulation results illustrate that compared with traditional methods, the error estimation algorithm proposed in this paper can effectively decrease positioning errors caused by time delays in acoustic communication.
Autors: Guangdi Xiao;Bo Wang;Zhihong Deng;Mengyin Fu;Yun Ling;
Appeared in: IEEE Sensors Journal
Publication date: Jan 2017, volume: 17, issue:2, pages: 504 - 513
Publisher: IEEE
 
» An Adaptive Bitrate Clock and Data Recovery Circuit for Communication Signal Analyzers
Abstract:
Many measurement instruments require an external timing reference to perform an accurate measurement. In equivalent-time oscilloscopes, for example, a trigger signal properly aligned to the data is essential, since they base their operation on a very accurate delay of the trigger, which is obtained by a clock and data recovery (CDR) circuit. In this paper, an adaptive bitrate CDR circuit for instrumentation applications is presented. It is designed in a standard 0.18- CMOS technology with a single supply voltage of 1.8 V and operates from 312.5 Mb/s to 2.5 Gb/s with a maximum power consumption of 140 mW and occupies an area of 1.5 mm 0.6 mm.
Autors: E. Guerrero;C. Sánchez-Azqueta;C. Gimeno;J. Aguirre;S. Celma;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Jan 2017, volume: 66, issue:1, pages: 191 - 193
Publisher: IEEE
 
» An Adaptive Least-Error Squares Filter-Based Phase-Locked Loop for Synchronization and Signal Decomposition Purposes
Abstract:
Without any doubt, phase-locked loops (PLLs) are the most popular and widely used technique for the synchronization purposes in the power and energy areas. They are also popular for the selective extraction of fundamental and harmonic/disturbance components of the grid voltage and current. Like most of the control algorithms, designing PLLs involves a tradeoff between the accuracy and dynamic response, and improving this tradeoff is what recent research efforts have focused on. These efforts are often based on designing advanced filters and using them as a preprocessing tool before the PLL input. A filtering technique that has received a little attention for this purpose is the least-error squares (LES)-based filter. In this paper, an adaptive LES filter-based PLL, briefly called the LES-PLL, for the synchronization and signal decomposition purposes is presented. The proposed LES filter can be understood as an adaptive complex-coefficient filter because its implementation involves cross couplings between orthogonal axes. The stability of designed LES-PLL is analyzed by the derivation of its small-signal model. Some control design guidelines are also presented. The effectiveness of proposed PLL structure is finally evaluated using experimental results.
Autors: Saeed Golestan;Esmaeil Ebrahimzadeh;Josep M. Guerrero;Juan C. Vasquez;Frede Blaabjerg;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Jan 2017, volume: 64, issue:1, pages: 336 - 346
Publisher: IEEE
 
» An Adaptive Transmission Scheme for Amplify-and-Forward Relaying Networks
Abstract:
In this paper, an adaptive scheme for amplify-and-forward relaying networks is proposed, which selects a certain transmission mode for each communication process. Depending on the instantaneous channel conditions, one of the following modes is selected: direct transmission with no cooperation, cooperative transmission with half-duplex relaying and maximal-ratio combining at the destination, or cooperative transmission with full-duplex relaying and maximal-ratio combining at the destination. A three-node network is considered, containing a single-antenna source, a two-antenna relay that is able to implement full-duplex communication, and a single-antenna destination. Energy normalization per block is assumed, so that in those modes using cooperation, the system’s transmission power is shared between source and relay. The performance analysis is provided in terms of outage probability and energy efficiency. We derive a tight approximate expression in closed form for the outage probability and an approximate expression in integral form for the mean energy consumption. The results show that our scheme outperforms all of transmission modes separately in terms of outage probability, while being more energy efficient than the cooperative transmission modes. In addition, the asymptotic analysis proves that the proposed scheme achieves full diversity order equal to 2, thus outperforming those schemes with direct transmission or full-duplex cooperation only.
Autors: Diana Pamela Moya Osorio;Edgar Eduardo Benítez Olivo;Hirley Alves;José Cândido Silveira Santos Filho;Matti Latva-aho;
Appeared in: IEEE Transactions on Communications
Publication date: Jan 2017, volume: 65, issue:1, pages: 66 - 78
Publisher: IEEE
 
» An Affine Arithmetic-Based Framework for Uncertain Power Flow and Optimal Power Flow Studies
Abstract:
This paper proposes a unified framework based on affine arithmetic for computing reliable enclosures of uncertain power flow (PF) and optimal power flow (OPF) solutions. The main idea is to formulate a generic mathematical programming problem under uncertainty by means of equivalent deterministic problems, and to identify the affine forms describing the data uncertainty by means of a signal processing technique based on principal components analysis. Compared to existing solution algorithms, this formulation presents greater flexibility, as it allows to find feasible solutions and inclusion of multiple equality and inequality constraints, and reduce the approximation errors to obtain better PF and OPF solution enclosures. Detailed numerical results are presented and discussed using a variety of realistic test systems, demonstrating the effectiveness of the proposed methodologies and comparing it to existing techniques for uncertain PF and OPF analysis.
Autors: Alfredo Vaccaro;Claudio A. Cañizares;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jan 2017, volume: 32, issue:1, pages: 274 - 288
Publisher: IEEE
 
» An Algorithm for Extraction of Threshold Voltage in Heterojunction TFETs
Abstract:
This paper presents and validates an algorithm based on two-dimensional Poisson's Equation, and proposed “tangents on surface potential plots” approach to extract threshold voltage in a silicon tunnel field effect transistor (TFET) with a SiGe layer at tunnel junction. The approach stands valid for homojunction Silicon TFET and SiGe channel Silicon TFET.
Autors: Rupam Goswami;Brinda Bhowmick;
Appeared in: IEEE Transactions on Nanotechnology
Publication date: Jan 2017, volume: 16, issue:1, pages: 90 - 93
Publisher: IEEE
 
» An Alternative Distributed Control Architecture for Improvement in the Transient Response of DC Microgrids
Abstract:
Distributed secondary control plays an important role in dc microgrids, since it ensures system control objectives, which are power sharing and dc-bus voltage stability. Previous studies have suggested using a control architecture that utilizes a parallel secondary bus voltage and current sharing compensation. However, the parallel controllers have a mutual impact on each other, which degrades the transient performance of the system. This paper reports on an alternative distributed secondary control architecture and controller design process, based on small-signal analysis to alleviate the mutual effect of the current sharing and bus voltage compensation, and to improve the transient response of the system. Experimental results confirm the improved transient performance in the current sharing control and dc-bus voltage stability utilizing the proposed control architecture.
Autors: Tuyen V. Vu;Sanaz Paran;Fernand Diaz-Franco;Touria El-Mezyani;Chris S. Edrington;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Jan 2017, volume: 64, issue:1, pages: 574 - 584
Publisher: IEEE
 
» An AMOLED Panel Test System Using Universal Data Driver ICs for Various Pixel Structures
Abstract:
In this paper, we propose a test system for active-matrix organic light emitting diode (AMOLED) panels with various pixel structures with the external compensation method. The proposed AMOLED panel test system employs universal data drive ICs to measure the current of a driving thin-film transistor (TFT) and the anode voltage of the OLED in various pixels by only programming the field-programmable gate array in the proposed test system. The universal data driver IC are fabricated and implemented in the proposed AMOLED panel test system whose test board is assembled with a 55-in full-high-definition AMOLED panel. A fabricated universal data driver IC includes 640 data channels with a 12-b linear gamma digital-to-analog converter and 12-bit variable current sources. To evaluate the repeatability error of the proposed panel test system, the current of the driving TFT is repeatedly measured and the measured maximum repeatability error is 9.8 nA. In addition, to evaluate the measurement accuracy of the proposed panel test system, the variation in the currents of the driving TFTs is measured and compensated for, and its maximum value after compensation is 26 nA.
Autors: Hyeon-Cheon Seol;Jong-Hyun Ra;Seong-Kwan Hong;Oh-Kyong Kwon;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Jan 2017, volume: 64, issue:1, pages: 189 - 194
Publisher: IEEE
 
» An Analytical Model of Drain Current in a Nanoscale Circular Gate TFET
Abstract:
This paper presents an analytical model of drain current in a silicon tunnel FET with a circular gate (CG TFET). The method involves the bifurcation of the complete geometry into a rectangular gate conventional TFET, and the CG TFET itself based on the number of solvable regions of the CG TFET. The 2-D Poisson equation is solved on the regions of focus of each structure, and both the substructures are mathematically connected through conditions of continuity to arrive at the solution for the original geometry. The effect of the circular gate is considered by segregating the circular region into a number of rectangular segments, and solving the Poisson equation on each of them. The model takes into account the effect of drain on channel potential, bandgap narrowing, and quantum correction. The model is validated by comparing the results with outputs from a TCAD simulation tool.
Autors: Rupam Goswami;Brinda Bhowmick;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Jan 2017, volume: 64, issue:1, pages: 45 - 51
Publisher: IEEE
 
» An Appeal to the Employers and Volunteers [Standards]
Abstract:
Discusses the importance of standards and the work of the IEEE Volunteers and industry members in general to develop new standards and actively work to enhance current standards in the industry.
Autors: Daleep Mohla;
Appeared in: IEEE Industry Applications Magazine
Publication date: Jan 2017, volume: 23, issue:1, pages: 82 - 82
Publisher: IEEE
 
» An Automated Design Methodology of RF Circuits by Using Pareto-Optimal Fronts of EM-Simulated Inductors
Abstract:
A new design methodology for radiofrequency circuits is presented that includes electromagnetic (EM) simulation of the inductors into the optimization flow. This is achieved by previously generating the Pareto-optimal front (POF) of the inductors using EM simulation. Inductors are selected from the Pareto front and their -parameter matrix is included in the circuit netlist that is simulated using an RF simulator. Generating the EM-simulated POF of inductors is computationally expensive, but once generated, it can be used for any circuit design. The methodology is illustrated both for a single-objective and a multiobjective optimization of a low noise amplifier.
Autors: Reinier González-Echevarría;Elisenda Roca;Rafael Castro-López;Francisco V. Fernández;Javier Sieiro;José María López-Villegas;Neus Vidal;
Appeared in: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Publication date: Jan 2017, volume: 36, issue:1, pages: 15 - 26
Publisher: IEEE
 
» An Automated Transient Stability Constrained Optimal Power Flow Based on Trajectory Sensitivity Analysis
Abstract:
This paper presents an automated transient stability constrained optimal power flow (ATSC-OPF). ATSC-OPF automates the design of linear transient stability constraints without online human interference thus is adaptive to the change of real-time operating conditions and suitable for applications in industrial dispatch programs. The design of transient stability constraints uses trajectory sensitivities to separate the integration of time-domain simulation from the online computing of optimal power flow. For identified unstable cases, a generic iterative algorithm is proposed to search corresponding stable base cases required to calculate trajectory sensitivities. ATSC-OPF identifies and limits only the key generators at critical time to minimize the extra computational burden brought by the transient stability constraints. The designed transient stability constraints are incorporated into ATSC-OPF only when needed in operation. The limits in the transient stability constraints are determined with manageable stability margin to avoid unnecessary increase of operational cost. The performance of ATSC-OPF is studied with the New England 39-bus system for a single-contingency situation and a 140-bus simplified NPCC system for a multicontingency situation.
Autors: Lei Tang;Wei Sun;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jan 2017, volume: 32, issue:1, pages: 590 - 599
Publisher: IEEE
 
» An Autonomous Water Monitoring and Sampling System for Small-Sized ASVs
Abstract:
In recent years, sensorized autonomous vehicles (either AUVs or ASVs) have been increasingly used for in situ water measurements. However, collection of water samplings at depth by small-sized ASVs and their subsequent physical/chemical analysis onboard remains difficult due to size and weight constraints. This paper addresses this issue and describes the design and testing of an autonomous water monitoring and sampling system intended for operations onboard small-sized man-portable ASVs. The system is designed to collect water samples up to 50 m in depth and to measure physical water parameters along the water column. The system is composed of a probe lowered by a winch measuring physical water parameters and able to collect water samples at different selectable depths. Once the probe is returned onboard, a water distribution system transfers the collected water samples to sensors lodged in the ASV for the monitoring of chemical parameters, or into containers to transport the samples to laboratories on the mainland. The system combines small dimensions, self-cleaning capabilities, low weight, and limited power consumption allowing it to be easily installable and used on an autonomous small-sized ASVs. The sampling system was installed and tested in a robotic small-sized catamaran belonging to the HydroNet ASV class.
Autors: Francesco Fornai;Gabriele Ferri;Alessandro Manzi;Francesco Ciuchi;Francesco Bartaloni;Cecilia Laschi;
Appeared in: IEEE Journal of Oceanic Engineering
Publication date: Jan 2017, volume: 42, issue:1, pages: 5 - 12
Publisher: IEEE
 
» An Auxiliary Variable-Aided Hybrid Message Passing Approach to Joint Channel Estimation and Decoding for MIMO-OFDM
Abstract:
This letter deals with message passing receiver design for joint channel estimation and decoding in MIMO-OFDM with unknown noise variance. The conventional factor graph representation for the system involves observation factors, which are functions of a number of variables in the form of multiplication and summation. In this work, by introducing some auxiliary variables, we further break each of the observation factors into several factors, which enables the use of hybrid mean field (MF), belief propagation (BP), and expectation propagation (EP) message passing to tackle the observation factors. It turns out that our approach is much more efficient than the existing approaches, leading to remarkable performance improvement as shown by simulation results.
Autors: Zhengdao Yuan;Chuanzong Zhang;Zhongyong Wang;Qinghua Guo;Jiangtao Xi;
Appeared in: IEEE Signal Processing Letters
Publication date: Jan 2017, volume: 24, issue:1, pages: 12 - 16
Publisher: IEEE
 
» An EEG Acquisition and Biomarker-Extraction System Using Low-Noise-Amplifier and Compressive-Sensing Circuits Based on Flexible, Thin-Film Electronics
Abstract:
This paper presents an electroencephalogram (EEG) acquisition and biomarker-extraction system based on flexible, thin-film electronics. There exist commercial, single-use, flexible, pre-gelled electrode arrays; however, these are fully passive, requiring cabling to transfer sensitive, low-amplitude signals to external electronics for readout and processing. This work presents an active EEG acquisition system on flex, based on amorphous silicon (a-Si) thin-film transistors (TFTs). The system incorporates embedded chopper-stabilized a-Si TFT low-noise amplifiers, to enhance signal integrity, and a-Si TFT compressive-sensing scanning circuits, to enable reduction of EEG data from many channels onto a single interface, for subsequent processing by a CMOS IC. Further, the system uses an algorithm, by which spectral-energy features, a key EEG biomarker, are extracted directly from the compressed signals. We demonstrate a prototype, performing EEG acquisition from a human subject, and compressed EEG reconstruction and seizure detection via analog replay of patient data. The TFT amplifier achieves a noise PSD of 230 nV/Hz. Seizure detection, at up to compression, achieves error rates 8%. Reconstruction is demonstrated at up to compression.
Autors: Tiffany Moy;Liechao Huang;Warren Rieutort-Louis;Can Wu;Paul Cuff;Sigurd Wagner;James C. Sturm;Naveen Verma;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Jan 2017, volume: 52, issue:1, pages: 309 - 321
Publisher: IEEE
 
» An Efficient Approach for Filling Gaps in Landsat 7 Satellite Images
Abstract:
Landsat 7 Enhanced Thematic Mapper Plus (ETM+) satellite imagery presents an important data source for many applications related to remote sensing. However, the scan line corrector (SLC) failure has seriously limited the scientific applications of ETM+ data since SLC failed permanently on May 31, 2003, resulting in about 22% of the image data missing in each scene. In this letter, we propose to apply a new method to fill the missing information (gap) in the satellite image without any spatial or spectral constraint applied on the neighborhood of missing pixels. The method can also simultaneously remove various types of noise, including Gaussian noise and impulse noise, affected in the acquisition process. This proposed concept is formulated as a consecutive multilevel Otsu and Two-Threshold Binary Decomposition to detect the boundary of the damaged region (gaps) and then reconstruct the edge of the damaged region based on boundary restoration. In the final step, we applied the well-known matrix completion as a low-rank approximation problem guided by boundary reconstructed. We achieve better approximation of the rank by minimizing the truncated nuclear norm with accelerated proximal gradient line, a method for convex optimization problems. The results show the capability of our approach to predict the missing values accurately in terms of quality, time, and without the need of outside information. This letter also shows encouraging results on both synthetic and real visual data sets.
Autors: Salma El Fellah;Mohammed Rziza;Mohamed El Haziti;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Jan 2017, volume: 14, issue:1, pages: 62 - 66
Publisher: IEEE
 
» An Efficient Component for Designing Signed Reverse Converters for a Class of RNS Moduli Sets of Composite Form ${2^{k}, 2^{P}-1}$
Abstract:
The application of residue number system (RNS) to digital signal processing lies in the ability to operate on signed numbers. However, the available RNS-to-binary (reverse) converters have been designed for unsigned numbers, which means that they do not produce signed outputs. Usually, some additional circuits are introduced at the output of the reverse converter to map the unsigned generated output into a signed number representation. This paper proposes a novel method to design reverse converters with signed output for a class of RNS moduli sets of composite form . The structure of the modulo adder used in the last stage of the proposed converters is modified in order to reuse the internal circuits to produce the signed output. This adder component is especially designed for achieving reverse converters with signed output, imposing very low area and delay overheads compared with unsigned converters. The proposed approach is applied to design reverse converters for different moduli sets and to implement application specific integrated circuits. Experimental results show that for a 4-moduli converter, the proposed design can outperform the traditional method to obtain signed outputs by improving the delay, chip-area, and energy consumption by up to 9%, 21%, and 35%, respectively.
Autors: Azadeh Alsadat Emrani Zarandi;Amir Sabbagh Molahosseini;Leonel Sousa;Mehdi Hosseinzadeh;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Jan 2017, volume: 25, issue:1, pages: 48 - 59
Publisher: IEEE
 
» An Efficient Framework for Unconditionally Secure Multiparty Computation
Abstract:
Threshold unconditionally secure multiparty computation (MPC) allows a set of mutually distrusting parties to securely compute an agreed function over some finite field in the presence of a computationally unbounded adversary, who can maliciously corrupt any out of the parties. Most of the known efficient MPC protocols are designed in the offline–online framework introduced in a seminal work by Beaver in CRYPTO 1991. In this framework, the parties generate shared random and private multiplication-triples during the offline phase, which are used later in the online phase for securely evaluating the multiplication gates in the circuit representing . The efficiency of the MPC protocols in this framework then relies on efficient ways of implementing the offline phase. In this paper, we propose a new and simple framework for generating shared and private random multiplication triples with unconditional security. The existing protocols approach this problem by first producing shared pairs of private and random values, followed by securely computing the shared product of each pair of values. The latter task involves a multiplication protocol for shared values that are typically communication intensive. Our framework takes a completely different approach and shuns the use of multiplication protocol. Namely, we ask the parties to verifiably share random multiplication triples and then securely extract shared random multiplication triples unknown to the adversary, from the shared triples. Realizing our framework in the asynchronous and hybrid network setting,1 we present the first ever MPC protocols with a linear (in the number of parties) communication overhead per multiplication gate in the circuit representing . These are significant improvements over the best known existing MPC protocols in the asynchronous and hybrid network setting with communication complexity and , respectively. Our framework when applied to the synchronous setting results in round-efficient MPC protocols.

In a hybrid network, it is assumed that the network is synchronous up to a certain “point” and asynchronous after that point onward. We assume a hybrid network with just one synchronous round in the beginning.

Autors: Ashish Choudhury;Arpita Patra;
Appeared in: IEEE Transactions on Information Theory
Publication date: Jan 2017, volume: 63, issue:1, pages: 428 - 468
Publisher: IEEE
 
» An Efficient Joint Formulation for Bayesian Face Verification
Abstract:
This paper revisits the classical Bayesian face recognition algorithm from Baback Moghaddam et al. and proposes enhancements tailored to face verification, the problem of predicting whether or not a pair of facial images share the same identity. Like a variety of face verification algorithms, the original Bayesian face model only considers the appearance difference between two faces rather than the raw images themselves. However, we argue that such a fixed and blind projection may prematurely reduce the separability between classes. Consequently, we model two facial images jointly with an appropriate prior that considers intra- and extra-personal variations over the image pairs. This joint formulation is trained using a principled EM algorithm, while testing involves only efficient closed-formed computations that are suitable for real-time practical deployment. Supporting theoretical analyses investigate computational complexity, scale-invariance properties, and convergence issues. We also detail important relationships with existing algorithms, such as probabilistic linear discriminant analysis and metric learning. Finally, on extensive experimental evaluations, the proposed model is superior to the classical Bayesian face algorithm and many alternative state-of-the-art supervised approaches, achieving the best test accuracy on three challenging datasets, Labeled Face in Wild, Multi-PIE, and YouTube Faces, all with unparalleled computational efficiency.
Autors: Dong Chen;Xudong Cao;David Wipf;Fang Wen;Jian Sun;
Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence
Publication date: Jan 2017, volume: 39, issue:1, pages: 32 - 46
Publisher: IEEE
 
» An Efficient Lattice Based Multi-Stage Secret Sharing Scheme
Abstract:
In this paper, we construct a lattice based threshold multi-stage secret sharing (MSSS) scheme according to Ajtai’s construction for one-way functions. In an MSSS scheme, the authorized subsets of participants can recover a subset of secrets at each stage while other secrets remain undisclosed. In this paper, each secret is a vector from a -dimensional lattice and the basis of each lattice is kept private. A -subset of participants can recover the secret(s) using their assigned shares. Using a lattice based one-way function, even after some secrets are revealed, the computational security of the unrecovered secrets is provided against quantum computers. The scheme is multi-use in the sense that to share a new set of secrets, it is sufficient to renew some public information such that a new share distribution is no longer required. Furthermore, the scheme is verifiable meaning that the participants can verify the shares received from the dealer and the recovered secrets from the combiner, using public information.
Autors: Hossein Pilaram;Taraneh Eghlidos;
Appeared in: IEEE Transactions on Dependable and Secure Computing
Publication date: Jan 2017, volume: 14, issue:1, pages: 2 - 8
Publisher: IEEE
 
» An Efficient Semidefinite Relaxation Algorithm for Moving Source Localization Using TDOA and FDOA Measurements
Abstract:
In this letter, we address the moving source localization problem by using time-difference-of-arrival and frequency-difference-of-arrival measurements. The localization problem is first reformulated based on the robust least squares criterion and then perform semidefinite relaxation (SDR) to obtain a convex semidefinite programming problem, which can be solved efficiently via optimization toolbox. Unlike several existing SDR localization methods requiring the initial estimate, the proposed method does not require this priori knowledge. The simulation results also show the superior positioning performance of the proposed method at high noise level than other existing methods.
Autors: Yunlong Wang;Ying Wu;
Appeared in: IEEE Communications Letters
Publication date: Jan 2017, volume: 21, issue:1, pages: 80 - 83
Publisher: IEEE
 
» An Empirical Comparison of Model Validation Techniques for Defect Prediction Models
Abstract:
Defect prediction models help software quality assurance teams to allocate their limited resources to the most defect-prone modules. Model validation techniques, such as -fold cross-validation, use historical data to estimate how well a model will perform in the future. However, little is known about how accurate the estimates of model validation techniques tend to be. In this paper, we investigate the bias and variance of model validation techniques in the domain of defect prediction. Analysis of 101 public defect datasets suggests that 77 percent of them are highly susceptible to producing unstable results– - selecting an appropriate model validation technique is a critical experimental design choice. Based on an analysis of 256 studies in the defect prediction literature, we select the 12 most commonly adopted model validation techniques for evaluation. Through a case study of 18 systems, we find that single-repetition holdout validation tends to produce estimates with 46-229 percent more bias and 53-863 percent more variance than the top-ranked model validation techniques. On the other hand, out-of-sample bootstrap validation yields the best balance between the bias and variance of estimates in the context of our study. Therefore, we recommend that future defect prediction studies avoid single-repetition holdout validation, and instead, use out-of-sample bootstrap validation.
Autors: Chakkrit Tantithamthavorn;Shane McIntosh;Ahmed E. Hassan;Kenichi Matsumoto;
Appeared in: IEEE Transactions on Software Engineering
Publication date: Jan 2017, volume: 43, issue:1, pages: 1 - 18
Publisher: IEEE
 
» An Energy Efficient Ethernet Strategy Based on Traffic Prediction and Shaping
Abstract:
Recently, different communities in computer science, telecommunication, and control systems have devoted a huge effort towards the design of energy efficient solutions for data transmission and network management. This paper collocates along this research line and presents a novel energy efficient strategy conceived for Ethernet networks. The proposed strategy, which exploits the opportunities offered by the IEEE 802.3az amendment to the Ethernet standard (known as energy efficient Ethernet) is based on the possibility of predicting the future traffic from the analysis of the current data flow. In agreement with the results of such a dynamic prediction, Ethernet links can be forced into a low power consumption state for variable intervals. Theoretical bounds are derived to detail how the performance figures depend on the parameters of the designed strategy and scale with respect to traffic load. Furthermore, simulation results carried out with both real and synthetic traffic traces are presented to prove the effectiveness of the strategy, which leads to considerable energy savings at the cost of only a limited bounded delay in data delivery.
Autors: Angelo Cenedese;Federico Tramarin;Stefano Vitturi;
Appeared in: IEEE Transactions on Communications
Publication date: Jan 2017, volume: 65, issue:1, pages: 270 - 282
Publisher: IEEE
 
» An Equal-Length Multiway Differential Metamaterial Phase Shifter
Abstract:
In a conventional differential phase shifter (DPS), to realize arbitrary phase shifts, the reference and main microstrip lines are of different lengths. This difference results in suboptimal integration density, which renders the wireless communication system implementation complex and bulky. This paper presents an equal-length multiway DPS based on metamaterials. The reference lines have identical dimensions and are of equal lengths with the main lines. The proposed structure covers a wide bandwidth by aligning the main line phase slope without degradation in return and insertion losses. A design optimization methodology is presented for wideband DPSs in the 0°–90° range. For demonstration, a six-way DPS has been designed and fabricated. The measurements show that the phase shifters have less than 5° differential phase stability and better than a 10-dB return loss, with an insertion loss less than 1.24 dB from 1.6 to 3.2 GHz.
Autors: Zeeshan Qamar;Shao Yong Zheng;Wing Shing Chan;Derek Ho;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Jan 2017, volume: 65, issue:1, pages: 136 - 146
Publisher: IEEE
 
» An Equivalence Principle for OFDM-Based Combined Bulk/Per-Subcarrier Relay Selection Over Equally Spatially Correlated Channels
Abstract:
In this paper, we propose a novel relay selection scheme for orthogonal frequency-division multiplexing systems by combining conventional bulk and per-subcarrier selection schemes and analyze its outage performance over equally spatially correlated channels. Specifically, the combined selection scheme selects only two relays at the first attempt and performs per-subcarrier selection over these two relays. We analyze the asymptotic outage performance of the combined selection scheme in the high signal-to-noise ratio (SNR) region and prove a generalized theorem. This theorem states that the combined selection can achieve an optimal outage probability equivalent to the per-subcarrier selection at a high SNR without using the full set of available relays for selection. This unique property is termed the equivalence principle, and it holds for all correlation conditions. To explore this principle, we consider three examples: decode-and-forward, fixed-gain amplify-and-forward (AF), and variable-gain AF relay systems. Furthermore, two extended applications, i.e., antenna selection and branch selection, are also considered to reveal the feasibility and the expandability of the equivalence principle. Our analysis is verified by Monte Carlo simulations. The proposed combined selection and the proved theorem provide a general and feasible solution to the tradeoff between system complexity and outage performance when relay selection is applied.
Autors: Shuping Dang;Justin P. Coon;Gaojie Chen;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jan 2017, volume: 66, issue:1, pages: 122 - 133
Publisher: IEEE
 
» An Event-Triggered Approach for Load Frequency Control With Supplementary ADP
Abstract:
The modern power system is evolving towards a new generation of smart grid, with significant benefits from the latest computer-based communication network technologies. Furthermore, as the incremental deployment of phase measurements units (PMUs) and the use of Smart Meters, there will be a substantial increase of the real-time system measurements. Under this trend, event-triggered control (ETC) will play an important role in reducing the communication and computation cost. In this paper, a novel ETC architecture design for load frequency control (LFC) with supplementary adaptive dynamic programming (ADP) is presented. The primary proportional-integral (PI) controller uses different proportional and integral thresholds for updating the actions, while the supplementary ADP controller is updated in an aperiodic manner. A strategy for the parameters calculation is introduced in a systematic way, and theoretical analysis of the ultimate boundedness for the closed-loop event-triggered system is also included. Simulation studies are carried out on one-area and three-area IEEE LFC benchmarks, and the results demonstrate the efficiency and effectiveness of the proposed design.
Autors: Lu Dong;Yufei Tang;Haibo He;Changyin Sun;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jan 2017, volume: 32, issue:1, pages: 581 - 589
Publisher: IEEE
 
» An Expectation Maximization Method for Joint Estimation of Emission Activity Distribution and Photon Attenuation Map in PET
Abstract:
A maximum likelihood expectation maximization (MLEM) method is proposed for joint estimation of emission activity distribution and photon attenuation map from positron emission tomography (PET) emission data alone. The method is appealing since: (i) it guarantees monotonic likelihood increase to a local extremum, (ii) does not require arbitrary parameters, and (iii) guarantees the positivity of the estimated distributions. Moreover, we propose a discrete Poisson data acquisition model and numerical algorithm for: (i) efficient graphics processing unit (GPU) based formulation, and (ii) a closed form exact solution for the MLEM update equations, which is essential for accurate and robust estimation. Numerical experiments indicate that in the presence of noise, joint EMAA estimation converges to the true emission activity distribution with root mean square errors of 4% and 0.5% respectively in estimation of lung- and myocardial emission activity distributions for a computational XCAT thorax phantom.
Autors: Alexander Mihlin;Craig S Levin;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Jan 2017, volume: 36, issue:1, pages: 214 - 224
Publisher: IEEE
 
» An Extended Shared Logarithmic Unit for Nonlinear Function Kernel Acceleration in a 65-nm CMOS Multicore Cluster
Abstract:
Energy-efficient computing and ultralow-power computing are strong requirements for various application areas, such as internet of things and wearables. While for some applications integer and fixed-point arithmetic suffice, others require a larger dynamic range, typically obtained using floating-point (FP) numbers. Logarithmic number systems (LNSs) have been proposed as energy-efficient alternative, since several complex FP operations translate into simple integer operations. However, additions and subtractions become nonlinear operations, which have to be approximated via interpolation. Even efficient LNS units (LNUs) are still larger than standard FP units (FPUs), rendering them impractical for most general-purpose processors. We show that, when shared among several cores, LNUs become a very attractive solution. A series of compact LNUs is developed, which provide significantly more functionality (such as transcendental functions) than other state-of-the-art designs. This allows, for example, to evaluate the atan2 function with three instructions for only 183.2 pJ/op at 0.8 V. We present the first shared-LNU architecture where these LNUs have been integrated into a multicore system with four 32-b-OpenRISC cores and show measurement results demonstrating that the shared-LNU design can be up to 4.1 more energy-efficient in common nonlinear processing kernels, compared with a similar area design with four private FPUs.
Autors: Michael Gautschi;Michael Schaffner;Frank K. Gürkaynak;Luca Benini;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Jan 2017, volume: 52, issue:1, pages: 98 - 112
Publisher: IEEE
 
» An FMCW Radar Transceiver Chip for Object Positioning and Human Limb Motion Detection
Abstract:
This letter proposes a frequency modulated continuous wave radar transceiver chip and a method to position objects as well as detect human limb motions. Implemented in 65-nm CMOS, the chip presents 2-GHz bandwidth centered at 15 GHz and consumes only 210 mW, with performance among the best of the state of the art. Using the chip, imaging experiments for moving targets and human arm raisings are carried out. In addition, the demonstration of both object positioning and human limb-motion detection by the FMCW radar mode is believed to be the first time. This letter is beneficial for navigation systems, surveillance applications, and more.
Autors: Yong Wang;Yuanjin Zheng;
Appeared in: IEEE Sensors Journal
Publication date: Jan 2017, volume: 17, issue:2, pages: 236 - 237
Publisher: IEEE
 
» An Impedance Transfer Function Formulation for Reduced-Order Macromodels of Subgridded Regions in FDTD
Abstract:
Recently, model order reduction was applied to the macromodel of a subgridded region in the method of finite-difference time domain (FDTD), where an admittance transfer function formulation was used to model materials with electric conductivity. In this communication, we develop an impedance transfer function formulation for the reduced-order macromodel of a subgridded region; this formulation may be used to model materials exhibiting magnetic conductivity. The two macromodel types may be used together, in a complementary fashion, to model fine-featured subgridded regions in FDTD that contain materials exhibiting both electric and magnetic conductivity. Additionally, this communication greatly extends the range of both the deterministic and the stochastic macromodeling techniques recently developed in FDTD, thus enabling the solution of a much wider range of problems in computational electromagnetics.
Autors: Ata Zadehgol;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Jan 2017, volume: 65, issue:1, pages: 401 - 404
Publisher: IEEE
 
» An Improved Analytical Model for Carrier Multiplication Near Breakdown in Diodes
Abstract:
The charge carrier contributions to impact ionization and avalanche multiplication are analyzed in detail. A closed-form analytical model is derived for the ionization current before the onset of breakdown induced by both injection current components. This model shows that the ratio of both injection current components affects the multiplication factor at relatively low fields before breakdown, but does not affect the reverse breakdown voltage. Furthermore, the model indicates that in case the ionization coefficients of electrons and holes are quite different in value, which depends upon the semiconductor material, the ionization coefficient of the charge carrier with the highest value can be extracted at those low fields. The one with the lowest value can be obtained by fitting the current close to breakdown. The model is compared and verified with TCAD simulations, and to some extent with experimental data, for silicon p-i-n diodes.
Autors: Raymond J. E. Hueting;Anco Heringa;Boni K. Boksteen;Satadal Dutta;Alessandro Ferrara;Vishal Agarwal;Anne Johan Annema;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Jan 2017, volume: 64, issue:1, pages: 264 - 270
Publisher: IEEE
 
» An Improved Azimuth Reconstruction Method for Multichannel SAR Using Vandermonde Matrix
Abstract:
To overcome the contradiction between wide swath and high resolution in synthetic aperture radar systems, a multichannel azimuth reconstruction method is investigated to unambiguously recover the Doppler spectrum. The proposed method is derived from the least squares principle by exploiting a Vandermonde component of the system matrix. The Vandermonde matrix is Doppler independent and data independent. Reconstruction filter weightings can be easily achieved, and performance, including signal-to-noise ratio (SNR) and azimuth ambiguity-to-signal ratio, can be explicitly expressed. By well-conditioning the Vandermonde matrix and coherent processing of all channels, the proposed method improves the reconstruction performance. In simulated reconstruction, compared with the conventional matrix inversion method, the SNR increases by approximately 30 dB.
Autors: Pu Cheng;Jianwei Wan;Qin Xin;Zhan Wang;Mi He;Yongjian Nian;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Jan 2017, volume: 14, issue:1, pages: 67 - 71
Publisher: IEEE
 
» An Improved Bound on the Fraction of Correctable Deletions
Abstract:
We consider codes over fixed alphabets against worst case symbol deletions. For any fixed , we construct a family of codes over alphabet of size with positive rate, which allow efficient recovery from a worst case deletion fraction approaching . In particular, for binary codes, we are able to recover a fraction of deletions approaching . Previously, even non-constructively, the largest deletion fraction known to be correctable with positive rate was , and around 0.17 for the binary case. Our result pins down the largest fraction of correctable deletions for -ary codes as , since is an upper bound even for the simpler model of erasures where the locations of the missing symbols are known. Closing the gap between and 1/2 for the limit of worst case deletions correctable by binary codes remains a tantalizing open question.
Autors: Boris Bukh;Venkatesan Guruswami;Johan Håstad;
Appeared in: IEEE Transactions on Information Theory
Publication date: Jan 2017, volume: 63, issue:1, pages: 93 - 103
Publisher: IEEE
 
» An Improved Ku-band MILO With Tapered Choke Cavity and Enlarged First Interaction Cavity
Abstract:
In order to further enhance the power capacity, and speed up the microwave start-up and saturation, an improved Ku-band magnetically insulated transmission line oscillator (MILO) with tapered choke cavity and enlarged first interaction cavity is proposed and investigated in this paper. The simplified plate model of MILO is analyzed to investigate the movement of individual electron. According to the theoretical analysis, the Ku-band MILO is optimized designed. In order to make the electrons emitted from the launch point of the cathode closer to the slow wave structure (SWS), especially the surface of the first interaction cavity, help to speed up the microwave start-up and saturation, the launch point of the cathode is optimized and designed 1.5 cm in front of the second choke vane. A tapered choke cavity is used to replace traditional uniform choke cavity, which helps further speed up the microwave start-up and saturation. An enlarged first interaction cavity with increased cavity gap is introduced to enhance the power capacity. Typical particle simulation results show that the improved Ku-band MILO can generate a microwave with a power of 1.65 GW and a frequency of 12.3 GHz under the diode voltage of 474 kV and the beam current of 42 kA. Compared with the traditional Ku-band MILO, the microwave start-up and saturation of the improved one are 2.5 and 5.5 ns faster, respectively. The power capacity of the improved Ku-band MILO is enhanced greatly due to that the RF electric field is decreased much from 1.3 to 1 MV/cm. At last, the experimental investigation of the improved Ku-band MILO is conducted. The device achieves a microwave output with a power of 1.2 GW, a frequency of 12.36 GHz, and a pulsewidth of 35 ns in the experiment. Both the power and the pulsewidth are enhanced significantly.
Autors: Tao Jiang;Juntao He;Jiande Zhang;Zhiqiang Li;Junpu Ling;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Jan 2017, volume: 64, issue:1, pages: 286 - 292
Publisher: IEEE
 
» An Improved Line-Reflect-Reflect-Match Calibration With an Enhanced Load Model
Abstract:
An improved line-reflect-reflect-match calibration with an enhanced load model is proposed. Different from load models used by existing LRRM algorithms, the load model used in the proposed algorithm takes into account both the parasitic capacitance and inductance. Using the same calibration standards as the classical LRRM and the enhanced LRRM, the proposed algorithm can accurately determine the load parasitics from raw measurements. Measurement results from 0.5 GHz to 110 GHz on a commercial impedance standards substrate show that the proposed LRRM outperforms the classical LRRM and the enhanced LRRM, and gives multiline TRL quality on-wafer calibrations.
Autors: Song Liu;Ilja Ocket;Arkadiusz Lewandowski;Dominique Schreurs;Bart Nauwelaers;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Jan 2017, volume: 27, issue:1, pages: 97 - 99
Publisher: IEEE
 
» An Improved Uplink Sparse Coded Multiple Access
Abstract:
Sparse coded multiple access (SCMA) has received considerable attention recently as a candidate multiple access scheme for 5G cellular systems. This letter proposes an improved uplink SCMA scheme where instead of the multi-dimensional constellation (MDC) mapping and a fixed number of nonzero elements per sparse codeword, a varying number of coded symbols from each user are directly mapped onto the resource elements. We show that the proposed SCMA scheme outperforms the MDC-SCMA scheme in terms of both error rate performance and receiver complexity when the user load is high.
Autors: Ming Zhao;Shengli Zhou;Wuyang Zhou;Jinkang Zhu;
Appeared in: IEEE Communications Letters
Publication date: Jan 2017, volume: 21, issue:1, pages: 176 - 179
Publisher: IEEE
 
» An Integrated Architecture for Software Defined and Virtualized Radio Access Networks with Fog Computing
Abstract:
Today, billions of communication devices connecting to wireless networks impose serious challenges to network deployment, management, and data processing. Among all emerging technologies tackling these challenges, SDNs decouple the control plane from the data plane to provide network programmability, and virtualization can share network and radio resources among various applications. On the other hand, fog computing offloads computing services from the cloud to the edge of networks, offering real-time data services to nearby data terminals. In this article, we present an integrated architecture for software defined and virtualized radio access networks with fog computing. We propose a design of software as a service called OpenPipe, which enables network-level virtualization. To integrate SDNs and network virtualization with fog computing, we adopt a hybrid control model with two hierarchical control levels, where an SDN controller forms the higher level and local controllers comprise the lower level. Typical use cases of the proposed network architecture are validated through laboratory demonstrations.
Autors: Kai Liang;Liqiang Zhao;Xiaoli Chu;Hsiao-Hwa Chen;
Appeared in: IEEE Network
Publication date: Jan 2017, volume: 31, issue:1, pages: 80 - 87
Publisher: IEEE
 
» An Intensity Gradient/Vegetation Fractional Coverage Approach to Mapping Urban Areas From DMSP/OLS Nighttime Light Data
Abstract:
Many studies have demonstrated the efficient extraction of the spatial extent of urban areas from Defense Meteorological Satellite Program/Operational Linescan System imagery using a fixed thresholding technique. These studies may underestimate and overestimate the extents of small and large cities, respectively. To overcome this problem, a new intensity gradient (IG) and vegetation fractional coverage (VFC) method is developed for identifying cities or towns, principally based on the assumption that there is a border around a city at which the nighttime light intensity decreases sharply. Using this method, the spatial extents of urban areas for two of the biggest countries in the world, namely China and the United States, were extracted in 2010. The urban areas thus identified are compared with the urban areas interpreted from Landsat Thematic Mapper imagery, and the results show that there is a significant linear relationship between the former and latter areas. This demonstrates that the IG/VFC model is effective for efficiently extracting the extent of urban areas from nighttime light imagery.
Autors: Minghong Tan;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Jan 2017, volume: 10, issue:1, pages: 95 - 103
Publisher: IEEE
 
» An Interior-Point Method for Modified Total Variation Exploiting Transform-Domain Sparsity
Abstract:
The total variation (TV) minimization can be utilized in a compressive sensing framework to recover a signal from a small number of measurements by searching for a signal with a sparse gradient. However, many natural signals of interest, such as natural images, generally have sparse representations in known transforms. Hence, the performance of the signal reconstruction procedure can be improved by also taking into account this transform-domain sparsity of the signal. Thus, the TV minimization problem can be modified by introducing an -norm penalty term. The -regularized TV minimization problem searches for a signal with a sparse gradient and a sparse representation in the given transform. The main contribution of this paper is the derivation of a customized interior-point method for solving the -regularized TV minimization problem that computes the search direction of the Newton method efficiently by exploiting the specific structure of the Hessian.
Autors: Uditha Lakmal Wijewardhana;Marian Codreanu;Matti Latva-aho;
Appeared in: IEEE Signal Processing Letters
Publication date: Jan 2017, volume: 24, issue:1, pages: 56 - 60
Publisher: IEEE
 
» An Investigation of Motor Topology Impacts on Magnet Defect Fault Signatures
Abstract:
This paper presents a study on the topology-dependent magnet defect fault signatures in permanent-magnet motors. A new analytical approach is introduced to characterize the fault signatures in stator back electromotive force (EMF) and current waveforms using magnetic equivalent circuit. Stator winding configuration, winding connection type and location of damaged rotor magnets are some of the physical properties affecting the fault signature characteristics. Several cases with different number of pole and slot are investigated through the proposed method. In addition, different winding connections (including star and delta connection), different winding configurations (including single and double layer, fractional and full coil pitch), and different magnet defect number and location are scrutinized. It is shown that there are some cases exhibiting different fault patterns than the ones obtained through well-known fault models defined in the literature. It is essential to take these discrepancies into account in order to avoid false alarms. In addition, it is observed that some of the fault signatures show up in the stator back EMF spectrum but not in the current spectrum due to location and severity of magnet defect, and design specs. Comparative 2-D finite-element simulations and experimental results justify the theoretical magnet defect fault analysis and show the efficacy of the proposed approach.
Autors: Mohsen Zafarani;Taner Goktas;Bilal Akin;Stephen E. Fedigan;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Jan 2017, volume: 64, issue:1, pages: 32 - 42
Publisher: IEEE
 
» An Iterative Method for Nonlinear Stochastic Optimal Control Based on Path Integrals
Abstract:
This paper proposes a new iterative solution method for nonlinear stochastic optimal control problems based on path integral analysis. First, we provide an iteration law for solving a stochastic Hamilton-Jacobi-Bellman (SHJB) equation associated to this problem, which is a nonlinear partial differential equation (PDE) of second order. Each iteration procedure of the proposed method is represented by a Cauchy problem for a linear parabolic PDE, and its explicit solution is given by the Feynman-Kac formula. Second, we derive a suboptimal feedback controller at each iteration by using the path integral analysis. Third, the convergence property of the proposed method is investigated. Here, some conditions are provided so that the sequence of solutions for the proposed iteration converges, and the SHJB equation is satisfied. Finally, numerical simulations demonstrate the effectiveness of the proposed method.
Autors: Satoshi Satoh;Hilbert J. Kappen;Masami Saeki;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Jan 2017, volume: 62, issue:1, pages: 262 - 276
Publisher: IEEE
 
» An On-Chip Triplexer Based on Silicon Bragg Grating-Assisted Multimode Interference Couplers
Abstract:
A silicon triplexer based on Bragg grating-assisted multimode interference (MMI) couplers is designed and experimentally demonstrated. Compared with the conventional MMI-based triplexers, the device length is not required to be the common multiple of beat length of different wavelengths. The simulated bandwidth is over 100 nm for 1310-nm band with the 3-D finite-different time-domain method. Experimental results of the fabricated on-chip triplexer show extinction ratios higher than 15 dB and insertion losses around 1 dB in all output ports. The total device size is only , which is the smallest size over the experimentally demonstrated triplexers ever reported.
Autors: Jingye Chen;Yuguang Zhang;Yaocheng Shi;
Appeared in: IEEE Photonics Technology Letters
Publication date: Jan 2017, volume: 29, issue:1, pages: 63 - 65
Publisher: IEEE
 
» An Optimal Service Strategy for Grouped Machine-Type Communications in Cellular Networks
Abstract:
Machine-type communication devices (MTCDs) served as groups are an efficient way to solve device management and resource allocation problems in cellular networks. We propose an MTCD group model based on the traffic of devices in the network. A group state transition matrix and revenue and constraint vectors are introduced and the optimal service solution is derived that the best service strategy is to serve devices in only two groups. Results can be used as a guide for cellular base stations to efficiently manage resources for MTCD applications.
Autors: Zebing Feng;Zhiyong Feng;Wei Li;T. Aaron Gulliver;
Appeared in: IEEE Communications Letters
Publication date: Jan 2017, volume: 21, issue:1, pages: 140 - 143
Publisher: IEEE
 
» An Outer-Rotor Flux-Switching Permanent-Magnet-Machine With Wedge-Shaped Magnets for In-Wheel Light Traction
Abstract:
This paper proposes a novel outer-rotor flux-switching permanent-magnet (OR-FSPM) machine with specific wedge-shaped magnets for in-wheel light-weight traction applications. First, the geometric topology is introduced. Then, the combination principle of stator slots and rotor poles for OR-FSPM machines is investigated. Furthermore, to demonstrate the relationship between performance specifications (e.g., torque and speed) and key design parameters and dimensions (e.g., rotor outer diameter and stack length) of OR-FSPM machines at preliminary design stage, an analytical torque-sizing equation is proposed and verified by two-dimensional (2-D) finite-element analysis (FEA). Moreover, optimizations of key dimensions are conducted on an initially designed proof-of-principle three-phase 12-stator-slot/22-rotor-pole prototyped machine. Then, based on 2-D-FEA, a comprehensive comparison between a pair of OR-FSPM machines with rectangular- and wedge-shaped magnets and a surface-mounted permanent-magnet (SPM) machine is performed. The results indicate that the proposed OR-FSPM machine with wedge-shaped magnets exhibits better flux-weakening capability, higher efficiency, and wider speed range than the counterparts, especially for torque capability, where the proposed wedge-shaped magnets-based one could produce 40% and 61.5% more torque than the rectangular-shaped magnets-based machine and SPM machine, respectively, with the same rated current density (5 A/mm2). Finally, the predicted performance of the proposed OR-FSPM machine is verified by experiments on a prototyped machine.
Autors: Wei Hua;Hengliang Zhang;Ming Cheng;Jianjian Meng;Chuang Hou;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Jan 2017, volume: 64, issue:1, pages: 69 - 80
Publisher: IEEE
 
» An Overlap-Splicing-Based Cavity in FBG Sensor for the Measurement of Strain and Temperature
Abstract:
A novel and simple overlap-splicing-based scheme is described to realize a shape-controllable Fabry–Perot cavity in a fiber bragg grating (FBG). A Gaussian function with a constant waist width is used to fit the cavity shape and its maximum value is decided by the overlap value. Non-uniform strain distribution along the FBG is introduced by the Gaussian shape cavity when stress is applied on the FBG. Using this method, it is possible to optimize the discrimination capability of the strain and temperature response of the FBG device. Experimental and simulation results are provided to support the feasibility of this method.
Autors: Ye Tian;Quan Chai;Yichen Meng;Yanlei Liu;Jing Ren;Song Wang;Jianzhong Zhang;Wenping Zhang;Elfed Lewis;Jun Yang;Zhihai Liu;Libo Yuan;
Appeared in: IEEE Photonics Technology Letters
Publication date: Jan 2017, volume: 29, issue:2, pages: 235 - 238
Publisher: IEEE
 
» An OVT Based on Conoscopic Interference and Position Sensitive Detector
Abstract:
The measurement mode of the existing optical voltage transducer (OVT) is mostly based on light intensity detection. In such a way, the OVT has some big issues, such as a light intensity dependency, a temperature drift, an additional birefringence in the crystal and a half-wave voltage limitation to its measurement range. A new OVT based on conoscopic interference and bi-dimensional position sensitive detector (PSD) is proposed in the paper, which can convert the electro-optical phase delay of the crystal to a rotation angle of spot pattern, and therefore, a high voltage can be measured by the PSD. Compared with the existing OVT, the measurement mode of the new one is independent of light intensity, capable of measuring the electro-optical phase delay from 0° to 180° linearly and directly, and has a wide measurement range with no restriction of the half-wave voltage. The rotation angle of the spot pattern is positioned by a bi-dimensional PSD and the new OVT has a good linearity better than 0.5%.
Autors: Yifan Huang;Qi Feng Xu;Qiao Tan;Zhikun Xu;
Appeared in: IEEE Sensors Journal
Publication date: Jan 2017, volume: 17, issue:2, pages: 340 - 346
Publisher: IEEE
 
» An RFID-Enabled Wireless Strain Gauge Sensor for Static and Dynamic Structural Monitoring
Abstract:
Strain gauge measurements are widely used in structural health monitoring and damage detection of existing infrastructures as well as in laboratory prototyping tests of new structures and materials. Wireless sensing of strain gauge is desirable in many practical applications because of the difficulty to access at the measurement point or to handle wired sensors. In this paper, we show a semi-passive wireless strain gauge sensor, which allows a high level of measurement accuracy comparable with that of wired strain sensors. It overcomes the limits and drawbacks of devices based on wireless sensor networks and those based on similar RFID-based sensors. The ability to perform measurements over long distances and to handle fast time-varying phenomena (e.g., vibration) makes the proposed device practical in realistic scenarios.
Autors: Emidio DiGiampaolo;Alessandro DiCarlofelice;Amedeo Gregori;
Appeared in: IEEE Sensors Journal
Publication date: Jan 2017, volume: 17, issue:2, pages: 286 - 294
Publisher: IEEE
 
» An Ultralow-Voltage Energy-Efficient Level Shifter
Abstract:
This brief presents an energy-efficient level shifter (LS) able to convert extremely low level input voltages to the nominal voltage domain. To obtain low static power consumption, the proposed architecture is based on the single-stage differential-cascode-voltage-switch scheme. Moreover, it exploits self-adapting pull-up networks to increase the switching speed and to reduce the dynamic energy consumption, while a split input inverting buffer is used as the output stage to further improve energy efficiency. When implemented in a commercial 180-nm CMOS process, the proposed design can up-convert from the deep subthreshold regime (sub-100 mV) to the nominal supply voltage (1.8 V). For the target voltage level conversion from 0.4 to 1.8 V, our LS exhibits an average propagation delay of 31.7 ns, an average static power of less than 60 pW, and an energy per transition of 173 fJ, as experimentally measured across the test chips.
Autors: Marco Lanuzza;Felice Crupi;Sandro Rao;Raffaele De Rose;Sebastiano Strangio;Giuseppe Iannaccone;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Jan 2017, volume: 64, issue:1, pages: 61 - 65
Publisher: IEEE
 
» Analysis and Design of a Passive Switched-Capacitor Matrix Multiplier for Approximate Computing
Abstract:
A switched-capacitor matrix multiplier is presented for approximate computing and machine learning applications. The multiply-and-accumulate operations perform discrete-time charge-domain signal processing using passive switches and 300 aF unit capacitors. The computation is digitized with a 6 b asynchronous successive approximation register analog-to-digital converter. The analyses of incomplete charge accumulation and thermal noise are discussed. The design was fabricated in 40 nm CMOS, and experimental measurements of multiplication are illustrated using matched filtering and image convolutions to analyze noise and offset. Two applications are highlighted: 1) energy-efficient feature extraction layer performing both compression and classification in a neural network for an analog front end and 2) analog acceleration for solving optimization problems that are traditionally performed in the digital domain. The chip obtains measured efficiencies of 8.7 TOPS/W at 1 GHz for the first application and 7.7 TOPS/W at 2.5 GHz for the second application.
Autors: Edward H. Lee;S. Simon Wong;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Jan 2017, volume: 52, issue:1, pages: 261 - 271
Publisher: IEEE
 
» Analysis and Design of an Electronic On-Load Tap Changer Distribution Transformer for Automatic Voltage Regulation
Abstract:
Current solutions for voltage regulation close to the consumers usually require technicians for manually changing the taps of the transformer, which may entail high maintenance costs and uncontrolled voltage levels. In this context, electronic on-load tap changers (OLTCs) are a prospective solution for present-day and future power grids, since they provide automatic voltage regulation. This paper presents the analysis and design guidelines for an electronic OLTC applied to a distribution transformer, encompassing the physical layout design for external access to the transformer tap terminals, the evaluation of current and voltage transients during the commutation process, and the dimensioning of the electronic switches and protection system. The dielectric withstand of the proposed physical layout is also analyzed through the finite-element approach, guaranteeing adequate insulation for the electronic circuits located outside the transformer tank, which facilitates circuitry maintenance and provides high modularity. The electronic switches and the protection circuit of the electronic OLTC are experimentally tested under normal and faulty operational conditions in a 5 kVA, 7.69 kV/220 V, single-phase earth return distribution transformer.
Autors: Josemar de Oliveira Quevedo;Fabricio Emmanuel Cazakevicius;Rafael Concatto Beltrame;Tiago Bandeira Marchesan;Leandro Michels;Cassiano Rech;Luciano Schuch;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Jan 2017, volume: 64, issue:1, pages: 883 - 894
Publisher: IEEE
 
» Analysis and Experimental Implementation of Grid Frequency Regulation Using Behind-the-Meter Batteries Compensating for Fast Load Demand Variations
Abstract:
This paper proposes a new grid frequency regulation (GFR) scheme using behind-the-meter battery energy storage systems (BESSs). The fast dynamic responses of the electrical BESSs enable buildings to compensate for the high-frequency components of load demand variations, through direct load control (DLC). An electrical system in a building, along with its building-level and device-level controllers, is considered to address the difficulties in the application of DLC, especially in communicating with several small-scale BESSs. A small-signal analysis is carried out using the aggregated responses of the generators and the DLC-enabled buildings to investigate the proposed GFR scheme, particularly with respect to the feedback controllers for the buildings. Simulation studies are performed using a test grid for various penetrations of the DLC-enabled buildings, and the test grid is implemented using a laboratory-scale microgrid. The proposed GFR is effective in reducing the frequency deviations and required reserve capacity of the generators, which is achieved by making small variations in the state-of-charge of the behind-the-meter battery.
Autors: Young-Jin Kim;Gerard Del-Rosario-Calaf;Leslie K. Norford;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jan 2017, volume: 32, issue:1, pages: 484 - 498
Publisher: IEEE
 
» Analysis and Implementation of an Ultra-Wide Tuning Range CMOS Ring-VCO With Inductor Peaking
Abstract:
A novel ring voltage controlled oscillator (VCO) topology is proposed which uses monolithic inductors as a peaking load. Four design examples have been fabricated and tested to verify the proposed circuit structure. The highest measured oscillation frequency is 25.07 GHz, with a tuning range of more than four octaves, and the active area is 0.0085 mm2. The design has the highest combined frequency and tuning range with the best figure of merit () comparable to previously published work.
Autors: Ke Li;Fanfan Meng;Dave J. Thomson;Peter Wilson;Graham. T. Reed;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Jan 2017, volume: 27, issue:1, pages: 49 - 51
Publisher: IEEE
 
» Analysis and Implementation of Hologram Lenses for See-Through Head-Mounted Display
Abstract:
We introduce an approach to implementation of see-through head-mounted displays using hologram lenses, which are categorized by holographic optical elements. The hologram lenses magnify displayed images and superimpose the magnified images on the real-world simultaneously, which allows system configuration to be compact. Here, we investigate imaging properties and optical issues of hologram lenses using the spectral analysis of light field. Also, the astigmatism of hologram lenses is analyzed and its compensation method is proposed and verified. We conclude by describing display results and a practical application of the proposed method.
Autors: Seungjae Lee;Byounghyo Lee;Jaebum Cho;Changwon Jang;Jonghyun Kim;Byoungho Lee;
Appeared in: IEEE Photonics Technology Letters
Publication date: Jan 2017, volume: 29, issue:1, pages: 82 - 85
Publisher: IEEE
 
» Analysis and Optimization of Caching and Multicasting in Large-Scale Cache-Enabled Heterogeneous Wireless Networks
Abstract:
Heterogeneous wireless networks (HetNets) provide a powerful approach to meeting the dramatic mobile traffic growth, but also impose a significant challenge on backhaul. Caching and multicasting at macro and pico base stations (BSs) are two promising methods to support massive content delivery and reduce backhaul load in HetNets. In this paper, we jointly consider caching and multicasting in a large-scale cache-enabled HetNet with backhaul constraints. We propose a hybrid caching design consisting of identical caching in the macro-tier and random caching in the pico-tier, and a corresponding multicasting design. By carefully handling different types of interferers and adopting appropriate approximations, we derive tractable expressions for the successful transmission probability in the general signal-to-noise ratio (SNR) and user density region as well as the high SNR and user density region, utilizing tools from stochastic geometry. Then, we consider the successful transmission probability maximization by optimizing design parameters, which is a very challenging mixed discrete-continuous optimization problem. By exploring structural properties, we obtain a near optimal solution with superior performance and manageable complexity. This solution achieves better performance in the general region than any asymptotically optimal solution, under a mild condition. The analysis and optimization results provide valuable design insights for practical cache-enabled HetNets.
Autors: Ying Cui;Dongdong Jiang;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Jan 2017, volume: 16, issue:1, pages: 250 - 264
Publisher: IEEE
 
» Analysis and Performance EnhancementPub _newline of Vector-Controlled VSC in HVDC Links Connected to Very Weak Grids
Abstract:
Voltage source converter (VSC)-based high-voltage direct current (HVDC) transmission systems have been employed widely in recent years. However, connecting a VSC-HVDC link to a very weak grid (a high-impedance grid) is challenging. A vector-controlled VSC is incapable of injecting/absorbing its maximum theoretical active power in such grids. A simple yet effective control system for a standard vector-controlled VSC in a very weak grid condition has not been reported in the literature. This paper, benefiting from a comprehensive small-signal model, presents a detailed analysis of the VSC dynamics and shows how the assumptions made for designing VSC regulators in strong grids are no longer valid in very weak grids. The paper then proposes and compares two straightforward solutions: retuning the control parameters and using an artificial bus for converter-grid synchronization. Both methods enable the VSC to operate at the maximum theoretical active power at a very weak grid condition (i.e., at unity short-circuit ratio) by minimal modification in the widely accepted vector control method. The advantages and disadvantages of each method are discussed. The analytical results are verified by detailed nonlinear time-domain simulation results.
Autors: Mohammadreza Fakhari Moghaddam Arani;Yasser Abdel-Rady I. Mohamed;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jan 2017, volume: 32, issue:1, pages: 684 - 693
Publisher: IEEE
 
» Analysis and Verification of DLL-Based GFSK Demodulator Using Multiple-IF-Period Delay Line
Abstract:
This brief presents a delay-locked-loop-based Gaussian frequency-shift keying (FSK) demodulator using a multiple-IF-period delay line. Theoretical analysis of the bit error rate (BER) performance is developed. The analysis result implies that the BER can be improved when a multiple-IF-period delay line is used instead of a single-IF-period delay line. To verify the analysis, a prototype chip was fabricated in a 0.11- CMOS process. When a binary Gaussian FSK (GFSK) signal carries 1-Mb/s data on a 3-MHz center frequency with a 160-kHz frequency deviation, the minimum required signal-to-noise ratio for 0.1% BER is reduced from 17.5 to 12.5 dB when a triple-IF-period delay line is used instead of a single-IF-period delay line. The implemented GFSK demodulator consumes 0.8 mA from a 1.2-V supply voltage.
Autors: Sangjin Byun;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Jan 2017, volume: 64, issue:1, pages: 6 - 10
Publisher: IEEE
 
» Analysis of Crosstalk Effects for Multiwalled Carbon Nanotube Bundle Interconnects in Ternary Logic and Comparison With Cu Interconnects
Abstract:
In this study, the crosstalk-induced effects are investigated in ternary logic by using the three-line bus architecture. The worst case crosstalk delays for both repeated and unrepeated interconnect and the peak crosstalk noise voltage on the victim net are investigated. Analyses have been done for global level multiwalled carbon nanotube (MWCNT) bundle and copper interconnects with carbon nanotube FET-based drivers and receivers at 22 nm node. According to the HSPICE simulations, the crosstalk delay and noise area in the MWCNT bundle interconnects are much smaller than the Cu wires for the ternary logic. In addition, the MWCNT bundle interconnects require a lower number of repeaters as compared to the Cu wires, which results in lower complexity and power consumption. The results indicate that utilizing the MWCNT interconnects instead of Cu wires in ternary systems leads to 63% shorter crosstalk delay without repeater insertion and 65% lower crosstalk noise area and 75% lower power consumption with repeater insertion. It is concluded from the results that the MWCNT bundle global wires are more suitable for ternary very large scale integration systems as compared to the Cu wires.
Autors: Maryam Rezaei Khezeli;Mohammad Hossein Moaiyeri;Ali Jalali;
Appeared in: IEEE Transactions on Nanotechnology
Publication date: Jan 2017, volume: 16, issue:1, pages: 107 - 117
Publisher: IEEE
 
» Analysis of Encoding Degradation in Spiking Sensors Due to Spike Delay Variation
Abstract:
Spiking sensors such as the silicon retina and cochlea encode analog signals into massively parallel asynchronous spike train output where the information is contained in the precise spike timing. The variation of the spike timing that arises from spike transmission degrades signal encoding quality. Using the signal-to-distortion ratio (SDR) metric with nonlinear spike train decoding based on frame theory, two particular sources of delay variation including comparison delay and queueing delay are evaluated on two encoding mechanisms which have been used for implementations of silicon array spiking sensors: asynchronous delta modulation and self-timed reset. As specific examples, is obtained from a 2T current-mode comparator, and is obtained from an M/D/1 queue for 1-D sensors like the silicon cochlea and an /D/1 queue for 2-D sensors like the silicon retina. Quantitative relations between the SDR and the circuit and system parameters of spiking sensors are established. The analysis method presented in this work will be useful for future specifications-guided designs of spiking sensors.
Autors: Minhao Yang;Shih-Chii Liu;Tobi Delbruck;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Jan 2017, volume: 64, issue:1, pages: 145 - 155
Publisher: IEEE
 
» Analysis of High-Field Hole Transport in Germanium and Silicon Nanowires Based on Boltzmann's Transport Equation
Abstract:
In this paper, high-field hole transport in germanium nanowires was studied by using Boltzmann's transport equation in an atomistic framework. The scattering mechanisms taken into account are phonon and surface roughness. The hole drift velocities of [110], [111], and [112]-oriented germanium nanowires showed negative-differential characteristics, while that of the [001] nanowire did not. The behavior of hole drift velocity was analyzed based on the highly nonparabolic and orientation-dependent valence band structure. High-field hole transport properties in silicon nanowires were also calculated, and the differences between germanium and silicon nanowires were discussed, focusing mainly on momentum and energy relaxation times. The [110], [111], and [112] silicon nanowires showed faster hole drift velocity at high field than the germanium nanowires with the same orientation. This was attributed to faster energy relaxation in silicon nanowires, which mitigates the negative differential mobility in silicon nanowires compared to germanium nanowires.
Autors: Hajime Tanaka;Jun Suda;Tsunenobu Kimoto;
Appeared in: IEEE Transactions on Nanotechnology
Publication date: Jan 2017, volume: 16, issue:1, pages: 118 - 125
Publisher: IEEE
 

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