Electrical and Electronics Engineering publications abstract of: 03-2017 sorted by title, page: 13

» Observer Design and Exponential Stabilization for Wave Equation in Energy Space by Boundary Displacement Measurement Only
Abstract:
In this technical note, we consider finite-time and exponential stabilization for one-dimensional wave equations by boundary displacement measurement only. We limit ourselves in the energy state space where the usual observability inequality is not valid anymore. However, in the optimal state space, the boundary displacement is indeed exactly observable. This motivates us to design observer via displacement output only for these systems. We first discuss a simple case as a motivation. An observer is designed and an output feedback control is then synthesized to make system finite-time stable in energy space. In this same spirit, we consider the same problem for an unstable wave equation and the finite-time stability is also achieved by displacement output feedback. Finally, we consider an anti-stable wave equation. A direct delayed output feedback control can achieve exponential stability with arbitrary decay rate. Simulation results are presented to validate the theoretical conclusions.
Autors: Hongyinping Feng;Bao-Zhu Guo;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Mar 2017, volume: 62, issue:3, pages: 1438 - 1444
Publisher: IEEE
 
» Octobot - A robot octopus points the way to soft robotics
Abstract:
The sun was sparkling on the Mediterranean sea on the afternoon when a graduate student from my lab tossed our prize robot into the water for the first time. I watched nervously as our electronic creation sank beneath the waves. But the bot didn't falter: When we gave it the command to swim, it filled its expandable mantle with water, then jetted out the fluid to shoot forward. When we ordered it to crawl, it stiffened its eight floppy arms in sequence to push itself along the sandy bottom and over scattered rocks. And when we instructed it to explore a tight space beneath the dock, the robot inserted its soft body into the narrow gap without difficulty.
Autors: Cecilia Laschi;
Appeared in: IEEE Spectrum
Publication date: Mar 2017, volume: 54, issue:3, pages: 38 - 43
Publisher: IEEE
 
» ODE to...Digital Humility [Last Word]
Abstract:
Autors: Christine Perakslis;
Appeared in: IEEE Technology and Society Magazine
Publication date: Mar 2017, volume: 36, issue:1, pages: 88 - 88
Publisher: IEEE
 
» Offline State-of-Health Estimation for High-Power Lithium-Ion Batteries Using Three-Point Impedance Extraction Method
Abstract:
This paper presents an offline state-of-health (SoH) estimation based on charge transfer resistance for high-power lithium-ion (Li-ion) batteries, such as lithium iron phosphate (LFP) batteries. As shown in the experimental results, the charge transfer resistance has a great aging change with battery degradation and good abilities against state-of-charge (SoC) drift and external resistance variation in the impedance parameter set of a single-time-constant equivalent circuit model (ECM), including ohmic resistance, charge transfer resistance, double-layer capacitance, and time constant, for SoH estimation. A fast and efficient three-point (TP) impedance extraction method is also proposed in this paper for accurately extracting the charge transfer resistance in offline SoH estimation. The results of long-term cycling test demonstrate that the TP impedance extraction method can successfully indicate the SoH of LFP batteries with low estimation error of 6.1%.
Autors: Hsiang-Fu Yuan;Lan-Rong Dung;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Mar 2017, volume: 66, issue:3, pages: 2019 - 2032
Publisher: IEEE
 
» Ogival Resonator Half-filled With DNG Metamaterial
Abstract:
A metallic cylindrical cavity with planar bases and with side walls consisting of two equal concave parabolic cylinders having the same focal line is considered. The symmetry plane through the focal line and the intersecting lines of the parabolic cylinders divides the resonator into two equal volumes, one filled with double positive material and the other with double negative antiisorefractive metamaterial. The exact electromagnetic field inside the resonator is obtained.
Autors: Piergiorgio L. E. Uslenghi;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Mar 2017, volume: 65, issue:3, pages: 1478 - 1479
Publisher: IEEE
 
» Oil Spill Detection via Multitemporal Optical Remote Sensing Images: A Change Detection Perspective
Abstract:
Oil spill monitoring in optical remote sensing (RS) images is a challenging task due to the complexity of target discrimination in an oil spill scenario. Differently from traditional oil spill detection methods that are mainly carried out in a monotemporal image, in this letter, a novel solution is given in a multitemporal domain by investigating potential capability of change detection (CD) techniques, and it mainly contributes to an unsupervised, semiautomatic, and efficient approach. It opens a new perspective for solving an oil spill detection problem. In particular, a coarse-to-fine multitemporal change analysis procedure is designed to investigate the spectral–temporal variation of change targets present in the scenario. Changes relevant and irrelevant to suspected oil spills are identified and discriminated according to a binary and a multiple CD process, respectively. The proposed approach provides a quick yet effective oil spill detection solution, which is valuable and important in practical applications. The proposed method was validated on two real multitemporal RS data sets presenting the oil spill event in northern Gulf of Mexico in 2010. Experimental results confirmed its effectiveness.
Autors: Sicong Liu;Mingmin Chi;Yangxiu Zou;Alim Samat;Jón Atli Benediktsson;Antonio Plaza;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Mar 2017, volume: 14, issue:3, pages: 324 - 328
Publisher: IEEE
 
» On Gaussian Channels With Feedback Under Expected Power Constraints and With Non-Vanishing Error Probabilities
Abstract:
In this paper, we consider single- and multi-user Gaussian channels with feedback under expected power constraints and with non-vanishing error probabilities. In the first of two contributions, we study asymptotic expansions for the additive white Gaussian noise (AWGN) channel with feedback under the average error probability formalism. By drawing ideas from Gallager and Nakiboğlu’s work for the direct part and the meta-converse for the converse part, we establish the -capacity and show that it depends on in general and so the strong converse fails to hold. Furthermore, we provide bounds on the second-order term in the asymptotic expansion. We show that for any positive integer , the second-order term is bounded between a term proportional to (where is the -fold nested logarithm function) and a term proportional to , where is the blocklength. The lower bound on the second-order term shows that feedback does provide an improvement in the maximal achievable rate over the case where no feedback is available. In our second contribution, we establish the -capacity region for the AWGN multiple access channel with feedback under the expected power constraint by combining ideas from ypothesis testing, information spectrum analysis, Ozarow’s coding scheme, and power control.
Autors: Lan V. Truong;Silas L. Fong;Vincent Y. F. Tan;
Appeared in: IEEE Transactions on Information Theory
Publication date: Mar 2017, volume: 63, issue:3, pages: 1746 - 1765
Publisher: IEEE
 
» On Improving Wireless Channel Utilization: A Collision Tolerance-Based Approach
Abstract:
Packet corruption caused by collision is a critical problem that hurts the performance of wireless networks. Conventional medium access control (MAC) protocols resort to collision avoidance to maintain acceptable efficiency of channel utilization. According to our investigation and observation, however, collision avoidance comes at the cost of miscellaneous overhead, which oppositely hurts channel utilization, not to mention the poor resiliency and performance of those protocols in face of dense networks or intensive traffic. Discovering the ability to tolerate collisions at the physical layer implementations of wireless networks, we in this paper propose , a protocol that advocates simultaneous accesses from multiple senders to a shared channel, i.e., optimistically allowing collisions instead of simply avoiding them. With a simple but effective design, addresses the key challenges in achieving collision tolerance, such as precise sender alignment and the control of transmission concurrency. We implement in 802.15.4 networks and evaluate its performance through extensive experiments with 21 TelosB nodes. The results demonstrate that is light-weight and enhances channel utilization by at least in general cases, compared with state-of-the-arts protocols.
Autors: Xiaoyu Ji;Yuan He;Jiliang Wang;Kaishun Wu;Daibo Liu;Ke Yi;Yunhao Liu;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: Mar 2017, volume: 16, issue:3, pages: 787 - 800
Publisher: IEEE
 
» On Microarchitectural Mechanisms for Cache Wearout Reduction
Abstract:
Hot carrier injection (HCI) and bias temperature instability (BTI) are two of the main deleterious effects that increase a transistor’s threshold voltage over the lifetime of a microprocessor. This voltage degradation causes slower transistor switching and eventually can result in faulty operation. HCI manifests itself when transistors switch from logic “0” to “1” and vice versa, whereas BTI is the result of a transistor maintaining the same logic value for an extended period of time. These failure mechanisms are especially acute in those transistors used to implement the SRAM cells of first-level (L1) caches, which are frequently accessed, so they are critical to performance, and they are continuously aging. This paper focuses on microarchitectural solutions to reduce transistor aging effects induced by both HCI and BTI in the data array of L1 data caches. First, we show that the majority of cell flips are concentrated in a small number of specific bits within each data word. In addition, we also build upon the previous studies, showing that logic “0” is the most frequently written value in a cache by identifying which cells hold a given logic value for a significant amount of time. Based on these observations, this paper introduces a number of architectural techniques that spread the number of flips evenly across memory cells and reduce the amount of time that logic “0” values are stored in the cells by switching OFF specific data bytes. Experimental results show that the threshold voltage degradation savings range from 21.8% to 44.3% depending on the application.
Autors: Alejandro Valero;Negar Miralaei;Salvador Petit;Julio Sahuquillo;Timothy M. Jones;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Mar 2017, volume: 25, issue:3, pages: 857 - 871
Publisher: IEEE
 
» On Next Generation Network Security
Abstract:
Autors: Nei Cato;
Appeared in: IEEE Network
Publication date: Mar 2017, volume: 31, issue:2, pages: 2 - 2
Publisher: IEEE
 
» On Optimizing Reservation-Based Intersection Controls
Abstract:
Tile-based reservation intersection control for autonomous vehicles has the potential to reduce intersection delays beyond optimized traffic signals. A major question in implementing reservations is the underdetermined problem of resolving conflicting reservation requests. Previous work studied prioritizing requests by first come first served or holding auctions at intersections, but the possibilities are infinite. Furthermore, although selfish routing behavior could affect the benefits of the reservation prioritization, reservation control has not been studied with user equilibrium routing due to its microsimulation definition. This paper addresses these issues by presenting an integer program formulation of the conflict point simplification of reservations. The feasible region is transformed, resulting in a more tractable integer program on conflict regions for dynamic traffic assignment. Because the integer program is NP-hard we present a polynomial-time heuristic. Finally, we demonstrate the potential utility of this heuristic by demonstrating objective functions that reduce travel time and energy consumption on a city network.
Autors: Michael W. Levin;Hagen Fritz;Stephen D. Boyles;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: Mar 2017, volume: 18, issue:3, pages: 505 - 515
Publisher: IEEE
 
» On Passivity Analysis and Passivation of Event-Triggered Feedback Systems Using Passivity Indices
Abstract:
While most of the work in the literature focuses on stability conditions for event-triggered systems, in this technical note we focus on passivity and passivation of event-triggered feedback interconnected systems of two input feed-forward output-feedback (IF-OF) passive systems. Passivity indices (levels) are used to measure the excess or shortage of passivity. It is shown that passivity indices (levels) of continuous feedback systems can be determined from passivity indices (levels) of individual subsystems. The passivation conditions to render a non-passive plant passive are also obtained based on passivity indices (levels). The results can be viewed as the extension of the well-known compositional property of passivity. Here we consider passivity in a unified event-triggered control scheme with event-triggered samplers located at both plant output and controller output. Under this scheme, we first derive the conditions to characterize passivity indices (levels) for the interconnected systems. The event-triggering condition proposed guarantees that these indices (levels) can be achieved. Then the passivation problem is considered and passivation conditions are provided. The passivation conditions depend on the passivity indices of the plant and controller and also the event-triggering condition, which reveals the trade off between desired passivity levels and communication resource utilization.
Autors: Feng Zhu;Meng Xia;Panos J. Antsaklis;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Mar 2017, volume: 62, issue:3, pages: 1397 - 1402
Publisher: IEEE
 
» On Reliability Management of Energy-Aware Real-Time Systems Through Task Replication
Abstract:
On emerging multicore systems, task replication is a powerful way to achieve high reliability targets. In this paper, we consider the problem of achieving a given reliability target for a set of periodic real-time tasks running on a multicore system with minimum energy consumption. Our framework explicitly takes into account the coverage factor of the fault detection techniques and the negative impact of Dynamic Voltage Scaling (DVS) on the rate of transient faults leading to soft errors. We characterize the subtle interplay between the processing frequency, replication level, reliability, fault coverage, and energy consumption on DVS-enabled multicore systems. We first develop static solutions and then propose dynamic adaptation schemes in order to reduce the concurrent execution of the replicas of a given task and to take advantage of early completions. Our simulation results indicate that through our algorithms, a very broad spectrum of reliability targets can be achieved with minimum energy consumption thanks to the judicious task replication and frequency assignment.
Autors: Mohammad A. Haque;Hakan Aydin;Dakai Zhu;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Mar 2017, volume: 28, issue:3, pages: 813 - 825
Publisher: IEEE
 
» On Secrecy Capacity of Minimum Storage Regenerating Codes
Abstract:
In this paper, we revisit the problem of characterizing the secrecy capacity of minimum storage regenerating (MSR) codes under the passive -eavesdropper model, where the eavesdropper has access to data stored on nodes and the repair data for an additional nodes. We study it from the information-theoretic perspective. First, some general properties of MSR codes as well as a simple and generally applicable upper bound on secrecy capacity are given. Second, a new concept of stable MSR codes is introduced, where the stable property is shown to be closely linked with secrecy capacity. Finally, a comprehensive and explicit result on secrecy capacity in the linear MSR scenario is present, which generalizes all related works in the literature and also predicts certain results for some unexplored linear MSR codes.
Autors: Kun Huang;Udaya Parampalli;Ming Xian;
Appeared in: IEEE Transactions on Information Theory
Publication date: Mar 2017, volume: 63, issue:3, pages: 1510 - 1524
Publisher: IEEE
 
» On Secure VLC Systems With Spatially Random Terminals
Abstract:
This letter investigates the secrecy performance of a visible light communication (VLC) system with a legitimate receiver and a group of eavesdroppers. Considering the randomness of the locations of the legitimate receiver and the eavesdroppers, the statistical characteristics of the signal-to-noise ratio over the VLC downlinks are characterized; then, we derive the closed-form analytical expressions for secrecy outage probability and the average secrecy capacity by using stochastic geometry method. Finally, simulations are carried on to verify our proposed analytical models.
Autors: Gaofeng Pan;Jia Ye;Zhiguo Ding;
Appeared in: IEEE Communications Letters
Publication date: Mar 2017, volume: 21, issue:3, pages: 492 - 495
Publisher: IEEE
 
» On Stabilization of Decentralized Systems Across Analog Erasure Links
Abstract:
We consider decentralized control of a process with multiple sensors, controllers and actuators interconnected by analog erasure links. To stabilize the process, feedback information has to be transmitted over both implicit signaling channels through the process and over external erasure channels. However, the signaling is complicated by the fact that in the absence of guaranteed acknowledgments, the transmitter cannot be certain that the receiver has received the intended data. Based on a data flow network model, a necessary condition for the mean squared stabilizability is obtained. Stabilizing algorithms are then designed to prove the sufficiency of the condition.
Autors: J. Liu;V. Gupta;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Mar 2017, volume: 62, issue:3, pages: 1411 - 1416
Publisher: IEEE
 
» On the Accuracy of Passive Source Localization Using Acoustic Sensor Array Networks
Abstract:
Angles of arrival (AOAs), gain ratios of arrival (GROAs), and time differences of arrival (TDOAs) are the three most commonly used signal metrics for source localization in acoustic sensor array networks. It is intuitive to expect a performance increase by combining those metrics. In this paper, we develop a feasible new source positioning framework using joint AOA-GROA-TDOA measurements, and establish the Cramér–Rao lower bound (CRLB) of the new method to quantify the performance increase compared with existing methods. Our analysis starts from the received waveforms rather than directly from the signal metrics, and hence these bounds characterize the fundamental limits of localization accuracy. The CRLB derived in this paper reveals that the GROAs can be utilized in conjunction with AOAs and TDOAs to improve the source localization accuracy. The improvement could be great for some special localization geometries. Moreover, the improvement from GROAs increases when the value of spatial coherence across the arrays is low and the signal propagation speed is high.
Autors: Ji-An Luo;Xiao-Ping Zhang;Zhi Wang;Xiao-Ping Lai;
Appeared in: IEEE Sensors Journal
Publication date: Mar 2017, volume: 17, issue:6, pages: 1795 - 1809
Publisher: IEEE
 
» On the Computation of $lambda$- Contractive Sets for Linear Constrained Systems
Abstract:
We present two theoretical results on the computation of - contractive sets for linear systems with state and input constraints. First, we show that it is possible to a priori compute a number of iterations that is sufficient to approximate the maximal - contractive set with a given precision using 1-step sets. Second, based on the former result, we provide a procedure for choosing so that the associated maximal - contractive set is guaranteed to approximate the maximal controlled invariant set with a given accuracy.
Autors: Moritz Schulze Darup;Mark Cannon;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Mar 2017, volume: 62, issue:3, pages: 1498 - 1504
Publisher: IEEE
 
» On the Construction of Polar Codes for Channels With Moderate Input Alphabet Sizes
Abstract:
Current deterministic algorithms for the construction of polar codes can only be argued to be practical for channels with small input alphabet sizes. In this paper, we show that any construction algorithm for channels with moderate input alphabet size, which follows the paradigm of “degrading after each polarization step,” will inherently be impractical with respect to a certain “hard” underlying channel. This result also sheds light on why the construction of low-density parity-check codes using density evolution is impractical for channels with moderate-sized input alphabets.
Autors: Ido Tal;
Appeared in: IEEE Transactions on Information Theory
Publication date: Mar 2017, volume: 63, issue:3, pages: 1501 - 1509
Publisher: IEEE
 
» On the Derivation of the Numerical Permittivity and Stability of the CDS-FDTD Implementation of High-Order Constitutive Relations
Abstract:
Recently, the derivation of the numerical permittivity and stability of the finite-difference time-domain (FDTD) implementation of a 4-pole complex rational function by using the central difference scheme (CDS) have been studied. In this communication, the accuracy and the stability limitation of this scheme are investigated. In addition, alternative FDTD implementation based on the Mobius transformation (MT) is presented. It is observed that the CDS implementation is less accurate and more stability restrictive than the MT counterpart.
Autors: Omar Ramadan;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Mar 2017, volume: 65, issue:3, pages: 1486 - 1489
Publisher: IEEE
 
» On the Estimation of Angle Rate in Radar
Abstract:
The direct measurement of the angle rate of moving objects using a radar with a spatially diverse electric field pattern, a measurement analogous to the measurement of the range rate of a moving objects, represents, along with the measurements of range, range rate, and angle, a fourth basic radar measurement. Recently introduced and experimentally demonstrated, the theoretical accuracy of the direct measurement of angle rate is derived in this paper, and it is compared to the measurements of range, range rate, and angle in the context of the optimal signal forms for the best measurement accuracy. Signal forms achieving optimal accuracy for each measurement are discussed; example implementations of high-accuracy measurements are compared to the optimal forms; and the limitations of simultaneous measurements of pairs of measurements are derived. Combining the angle rate measurement with the three other standard radar measurements may provide future radar systems the capability to simultaneously and instantaneously measure the position and 3-D trajectory of moving objects without compromising the accuracy of any individual measurement.
Autors: Jeffrey A. Nanzer;Matthew D. Sharp;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Mar 2017, volume: 65, issue:3, pages: 1339 - 1348
Publisher: IEEE
 
» On the Exploitation of Admittance Measurements for Wired Network Topology Derivation
Abstract:
The knowledge of the topology of a wired network is often of fundamental importance. For instance, in the context of power line communications networks it is helpful to implement data routing strategies, while in power distribution networks and smart microgrids it is required for grid monitoring and for power flow management. In this paper, we use the transmission line theory to shed new light and to show how the topological properties of a wired network can be found exploiting admittance measurements at the nodes. An analytic proof is reported to show that the derivation of the topology can be done in complex networks under certain assumptions. We also analyze the effect of the network background noise on admittance measurements. In this respect, we propose a topology derivation algorithm that works in the presence of noise. We finally analyze the performance of the algorithm in a setup that is typical of power line distribution networks.
Autors: Federico Passerini;Andrea M. Tonello;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Mar 2017, volume: 66, issue:3, pages: 374 - 382
Publisher: IEEE
 
» On the Limitation of Spectral Methods: From the Gaussian Hidden Clique Problem to Rank One Perturbations of Gaussian Tensors
Abstract:
We consider the following detection problem: given a realization of a symmetric matrix X of dimension , distinguish between the hypothesis that all upper triangular variables are independent and identically distributed (i.i.d). Gaussians variables with mean 0 and variance 1 and the hypothesis, where X is the sum of such matrix and an independent rank-one perturbation. This setup applies to the situation, where under the alternative, there is a planted principal submatrix B of size for which all upper triangular variables are i.i.d. Gaussians with mean 1 and variance 1, whereas all other upper triangular elements of X not in B are i.i.d. Gaussians variables with mean 0 and variance 1. We refer to this as the “Gaussian hidden clique problem.” When (), it is possible to solve this detection problem with probability by computing the spectrum of X and considering the largest eigenvalue of X. We prove that this condition is tight in the following sense: when no algorithm that examines only the eigenvalues of X can detect the existence of a hidden Gaussian clique, with error probability vanishing as . We prove this result as an immediate consequence of a more general result on rank-one perturbations of -dimensional Gaussian te sors. In this context, we establish a lower bound on the critical signal-to-noise ratio below which a rank-one signal cannot be detected.
Autors: Andrea Montanari;Daniel Reichman;Ofer Zeitouni;
Appeared in: IEEE Transactions on Information Theory
Publication date: Mar 2017, volume: 63, issue:3, pages: 1572 - 1579
Publisher: IEEE
 
» On the Link Between L1-PCA and ICA
Abstract:
Principal component analysis (PCA) based on L1-norm maximization is an emerging technique that has drawn growing interest in the signal processing and machine learning research communities, especially due to its robustness to outliers. The present work proves that L1-norm PCA can perform independent component analysis (ICA) under the whitening assumption. However, when the source probability distributions fulfil certain conditions, the L1-norm criterion needs to be minimized rather than maximized, which can be accomplished by simple modifications on existing optimal algorithms for L1-PCA. If the sources have symmetric distributions, we show in addition that L1-PCA is linked to kurtosis optimization. A number of numerical experiments illustrate the theoretical results and analyze the comparative performance of different algorithms for ICA via L1-PCA. Although our analysis is asymptotic in the sample size, this equivalence opens interesting new perspectives for performing ICA using optimal algorithms for L1-PCA with guaranteed global convergence while inheriting the increased robustness to outliers of the L1-norm criterion.
Autors: Rubén Martín-Clemente;Vicente Zarzoso;
Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence
Publication date: Mar 2017, volume: 39, issue:3, pages: 515 - 528
Publisher: IEEE
 
» On the Merits of Tetrapolar Impedance Spectroscopy for Monitoring Lithium Concentration Variations in Human Blood Plasma
Abstract:
Bipolar disorder is characterized as a manic-depressive psychiatric syndrome with life-threatening risks to the patient. Diagnosed individuals undergo long-term lithium therapy which has proven to be effective for mood stabilization. Maintaining blood lithium concentration levels within a narrow therapeutic window between 0.6 and 1.5 mM is vital for the patient as slightly elevated concentrations of the order of 0.1 mM can be toxic. This paper aims to evaluate the merits of tetrapolar electrical impedance spectroscopy as an alternative method in monitoring blood lithium levels. Measurements were performed using a custom-made tetrapolar probe in human blood plasma with lithium concentrations covering the therapeutic range. The results indicate a limit of detection less than 0.1 mM and a response time of less than 5 s. Prediction of lithium concentration levels using impedance values is in good agreement with conventional standard techniques to approximately 0.05 mM. This technique provides a basis for further development of instrumentation for point of care healthcare technologies.
Autors: Loukas Constantinou;Iasonas F. Triantis;Michelle Hickey;Panayiotis A. Kyriacou;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Mar 2017, volume: 64, issue:3, pages: 601 - 609
Publisher: IEEE
 
» On the Multi-User Multi-Cell Massive Spatial Modulation Uplink: How Many Antennas for Each User?
Abstract:
Massive spatial modulation aided multiple-input multiple-output (SM-MIMO) systems have recently been proposed as a novel combination of SM and of conventional massive MIMO, where the base station (BS) is equipped with a large number of antennas and simultaneously serves multiple user equipment (UE) that employ SM for their uplink transmission. Since the massive SM-MIMO concept combines the benefits of both the SM and massive MIMO techniques, it has recently attracted substantial research interest. In this paper, we study the achievable uplink spectral efficiency (SE) of a multi-cell massive SM-MIMO system, and derive closed-form expressions to asymptotically lower-bound the SE yielded by two linear BS combining schemes, including maximum ratio combining and zero forcing combining, when a sufficiently large number of BS antennas are equipped. The derivation takes into account the impact of transmitter spatial correlations, imperfect channel estimations, user-specific power controls, and different pilot reuse factors. The proposed asymptotic bounds are shown to be tight, even when the scale of BS antennas is limited. The new SE results facilitate a system-level investigation of the optimal number of uplink transmit antennas (TAs) with respect to SE maximization. Explicitly, we provide theoretical insights on the SE of massive SM-MIMO systems. Furthermore, we demonstrate that massive SM-MIMO systems are capable of outperforming the SE of conventional massive MIMOs relying on single-TA UEs.
Autors: Longzhuang He;Jintao Wang;Jian Song;Lajos Hanzo;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Mar 2017, volume: 16, issue:3, pages: 1437 - 1451
Publisher: IEEE
 
» On the Optimization of Generators for Offshore Direct Drive Wind Turbines
Abstract:
The objective of this paper is to optimize direct drive permanent magnet synchronous generators for offshore direct drive wind turbines in order to reduce the cost of energy. A 6 MW wind turbine design is assumed and parametric electromagnetic and structural generator models are introduced for a surface-mounted magnet generator topology (using magnets with high ) and a flux-concentrating variant (using magnets with lower ). These are optimized using a hybrid genetic algorithm and pattern search process and the results show that the surface-mounted permanent magnet generator produces the lower cost of energy. The choice of objective function is addressed and it is found that a simplified metric incorporating generator cost and losses proxy produces similar designs to a full cost of energy calculation. Further steps to improve the quality of the model include the effect of generator mass on the design and cost of the turbine tower and foundation, which can add €0.4 m to the turbine cost. Further optimizations are carried out to show the impacts of magnetic material costs (doubling this leads to a €1.1/MWh increase in cost of energy) and generator diameter limits (increasing the upper limit from 6 to 8 m leads to a 0.9% drop in cost of energy) have on the choice of optimum independent variables.
Autors: Alasdair McDonald;Nurul Azim Bhuiyan;
Appeared in: IEEE Transactions on Energy Conversion
Publication date: Mar 2017, volume: 32, issue:1, pages: 348 - 358
Publisher: IEEE
 
» On the Performance of X-Duplex Relaying
Abstract:
In this paper, we study an X-duplex relay system with one source, one amplify-and-forward relay, and one destination, where the relay is equipped with a shared antenna and two radio frequency (RF) chains used for transmission or reception. X-duplex relay can adaptively configure the connection between its RF chains and antenna to operate in either half-duplex (HD) or full-duplex (FD) mode, according to the instantaneous channel conditions. We first derive the distribution of the signal to interference plus noise ratio, based on which we then analyze the outage probability, average symbol error rate (SER), and average sum rate. We also investigate the X-duplex relay with power allocation and derive the lower bound and upper bound of the corresponding outage probability. Both analytical and simulated results show that the X-duplex relay achieves a better performance over pure FD and HD schemes in terms of SER, outage probability and average sum rate, and the performance floor caused by the residual self interference can be eliminated using flexible RF chain configurations.
Autors: Shuai Li;Mingxin Zhou;Jianjun Wu;Lingyang Song;Yonghui Li;Hongbin Li;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Mar 2017, volume: 16, issue:3, pages: 1868 - 1880
Publisher: IEEE
 
» On the Proprieties of the Differential Cross-Saturation Inductance in Synchronous Machines
Abstract:
The cross-saturation inductance is a mutual inductance due to the saturation of portions of the magnetic circuit of one axis caused by the current of the other axis. In sensorless drives, the differential cross-saturation inductance causes an error in the estimation of the rotor position when it is performed by means of the high frequency signal injection methods. The knowledge of the properties of cross-saturation inductance is therefore essential to minimize any distortion effect on the position estimation. This paper aims to describe the properties of the cross-saturation inductance for different types of synchronous machine, such as reluctance, interior permanent-magnet, and surface-mounted permanent-magnet machines. Information is also given to predict the error in the estimated position for any stator currents, useful for implementing an error compensation technique or to detect the feasible operating regions using the high frequency voltage injection technique. The analysis is supported by finite element simulations and experimental measurements.
Autors: Damiano Mingardi;Mattia Morandin;Silverio Bolognani;Nicola Bianchi;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Mar 2017, volume: 53, issue:2, pages: 991 - 1000
Publisher: IEEE
 
» On the Spectral and Energy Efficiency of Full-Duplex Small-Cell Wireless Systems With Massive MIMO
Abstract:
The achievable rate of full-duplex (FD) small-cell systems with massive multiple-input multiple-output (MIMO), in which a low-power base station (BS) equipped with large antenna arrays sends/receives data to and from multiple half-duplex (HD) users at the same time on the same frequency, is investigated. The BS uses imperfect channel state information (CSI) obtained from received pilots, nonideal hardware, and a linear transmitter and receiver, i.e., zero-forcing (ZF) or maximum-ratio transmission/maximum-ratio combining (MRT/MRC), to process the signals. The approximate closed-form expressions of the achievable rate for both the ZF and MRT/MRC processing are derived and used to analyze the effect of the number of antennas and the hardware imperfection on the self-interference (SI), which is a bottleneck of the FD systems. To maximize the spectral efficiency (SE) and the energy efficiency (EE) of this system, two nonconvex power-allocation optimization problems are formulated and solved by utilizing the sequential convex approximation technique and the fractional programming technique. Two iterative algorithms are proposed with proved local convergence. Numerical results illustrate that the analytical approximation of achievable rate matches well with the Monte Carlo simulation. It is also shown that the ZF processing has greater ability to suppress SI, compared with MRT/MRC processing. The proposed power-allocation algorithms are shown to increase the SE and EE significantly, compared with the uniform power-allocation scheme when the BS is equipped with moderately large antenna arrays.
Autors: Yi Li;Pingzhi Fan;Anatolii Leukhin;Lingjia Liu;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Mar 2017, volume: 66, issue:3, pages: 2339 - 2353
Publisher: IEEE
 
» On the Sunny Side : Integrating Solar Energy at Increasing Rates [Guest Editorial]
Abstract:
The articles in this special section address the issues involved with the integrated of distributed energy resources (DERs) into the electric grid.
Autors: Barry Mather;Guohui Yuan;
Appeared in: IEEE Power and Energy Magazine
Publication date: Mar 2017, volume: 15, issue:2, pages: 14 - 18
Publisher: IEEE
 
» On the Uniqueness of the IEEE Industrial Electronics Society's Structure and Management [Message from the President]
Abstract:
Presents the President's message for this issue of the publication.
Autors: Kamal Al-Haddad;
Appeared in: IEEE Industrial Electronics Magazine
Publication date: Mar 2017, volume: 11, issue:1, pages: 4 - 5
Publisher: IEEE
 
» On Thermal Impact of Chaotic Frequency Modulation SPWM Techniques
Abstract:
Chaotic sinusoidal pulse width modulation (SPWM) can be used to suppress the electromagnetic interference in power converters. In this paper, a mathematical method for estimating power losses in insulated-gate bipolar transistors and freewheeling diodes occurring under chaotic frequency modulation SPWM (CFM-SPWM) switching is proposed. This method is based on the features of the chaotic mapping and uses semiconductor datasheet information to calculate the power losses in a discrete way. Analytical expressions and approximations for estimating the losses for the cases of SPWM and CFM-SPWM switching, respectively, are presented. This paper includes a quantitative comparison of the losses under the two previously mentioned cases. It is confirmed that CFM-SPWM does not result in higher power losses when it greatly improves electromagnetic compatibility of power converters, and hence, its adoption will not require any modified converter thermal design. Experimental results taken from a single-phase ac–dc converter are presented to prove the validity of the proposed method and associated results.
Autors: Hong Li;Zhichang Yang;Boyu Wang;Vassilios G. Agelidis;Bo Zhang;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Mar 2017, volume: 64, issue:3, pages: 2032 - 2043
Publisher: IEEE
 
» On Using Micro-Clouds to Deliver the Fog
Abstract:
The cloud is scalable and cost-efficient, but it isn't ideal for hosting all applications. Fog computing proposes an alternative of offloading some computation to the edge. Which applications to offload, where to send them, and when this should occur isn't entirely clear yet due to a lack of understanding of potential edge infrastructures. Through a number of experiments, the authors showcase the feasibility and readiness of micro-clouds formed by collections of Raspberry Pis to host a range of fog applications, particularly for network-constrained environments.
Autors: Yehia Elkhatib;Barry Porter;Heverson B. Ribeiro;Mohamed Faten Zhani;Junaid Qadir;Etienne Rivière;
Appeared in: IEEE Internet Computing
Publication date: Mar 2017, volume: 21, issue:2, pages: 8 - 15
Publisher: IEEE
 
» On-Line Load Sensitivity Identification in LV Distribution Grids
Abstract:
This letter proposes a new on-line load sensitivity identification by means of power electronics-based devices. Applying a voltage and frequency perturbation and measuring the consumed power of the loads, the proposed method computes in real time the voltage and frequency dependency of the load active and reactive power. In this letter, a smart transformer application has been proposed, but the method is general for any power electronics converter able to influence dynamically the voltage and frequency in the grid.
Autors: Giovanni De Carne;Marco Liserre;Costas Vournas;
Appeared in: IEEE Transactions on Power Systems
Publication date: Mar 2017, volume: 32, issue:2, pages: 1570 - 1571
Publisher: IEEE
 
» On-Site Non-Invasive Current Monitoring of Multi-Core Underground Power Cables With a Magnetic-Field Sensing Platform at a Substation
Abstract:
Current monitoring can facilitate preemptive action in electrical distribution network, so as to relieve power congestion, improve transmission efficiency, and ensure network reliability. The non-invasive current sensing devices are promising since they do not require contacting hazardous high voltage and their installation is much easier compared with invasive current sensing devices. However, the existing non-invasive current sensing devices, such as current clamps and Rogowski coils are only applicable for measuring single-core underground power cables. In this paper, we established a non-invasive technique, that can monitor the currents of a multi-core underground power cable by measuring the emitted magnetic field around the cable surface. The additional magnetic fields generated by induced and leakage currents on the cables were firstly evaluated. Magnetoresistive (MR) sensors in a circular array were adopted to measure magnetic field around the cable surface, and a triple-layer shielding was designed to reduce the effects of external interference. Regarding intrinsic noise in MR sensors (e.g., 1/f noise and thermal noise), magnetic flux concentrators were supplemented to improve the signal-to-noise ratio. The developed platform was tested in a substation, and the reconstructed results closely matched the real geometrical configuration and current records of the tested cable. Apart from the non-invasive feature, the platform also shows great potential to improve the sensing capability of current amplitude and frequency compared with CTs by adopting MR sensors.
Autors: Ke Zhu;Wei Han;Wing Kin Lee;Philip W. T. Pong;
Appeared in: IEEE Sensors Journal
Publication date: Mar 2017, volume: 17, issue:6, pages: 1837 - 1848
Publisher: IEEE
 
» ON/OFF Traffic Shaping in the Internet: Motivation, Challenges, and Solutions
Abstract:
Tremendous traffic on the Internet exhibits ON/OFF patterns. In the past, the generation of such ON/OFF traffic was mainly attributed to TCP and application characteristics. Nowadays, however, much traffic is often intentionally shaped into an ON/OFF pattern for achieving certain optimized system performance or resulting from characteristics of some new applications. In this article, we present a comprehensive survey on the ON/OFF traffic shaping in the current Internet. We first introduce the motivations behind ON/OFF traffic shaping in different fields based on different system optimization objectives and application characteristics. We then introduce the impacts of ON/OFF traffic on packet drop probability, real-time applications, and also its interaction with TCP's congestion control mechanism. We further present a survey on existing mechanisms for mitigating these impacts in various aspects. We introduce how each of these mechanisms works, and discuss their merits and deficiencies. Finally, we conclude this article with some future directions for ON/OFF traffic shaping in the Internet.
Autors: Yongxiang Zhao;Baoxian Zhang;Cheng Li;Changjia Chen;
Appeared in: IEEE Network
Publication date: Mar 2017, volume: 31, issue:2, pages: 48 - 57
Publisher: IEEE
 
» Online and Scalable Unsupervised Network Anomaly Detection Method
Abstract:
Nowadays, network intrusion detectors mainly rely on knowledge databases to detect suspicious traffic. These databases have to be continuously updated which requires important human resources and time. Unsupervised network anomaly detectors overcome this issue by using “intelligent” techniques to identify anomalies without any prior knowledge. However, these systems are often very complex as they need to explore the network traffic to identify flows patterns. Therefore, they are often unable to meet real-time requirements. In this paper, we present a new online and real-time unsupervised network anomaly detection algorithm (ORUNADA). Our solution relies on a discrete time-sliding window to update continuously the feature space and an incremental grid clustering to detect rapidly the anomalies. The evaluations showed that ORUNADA can process online large network traffic while ensuring a low detection delay and good detection performance. The experiments performed on the traffic of a core network of a Spanish intermediate Internet service provider demonstrated that ORUNADA detects in less than half a second an anomaly after its occurrence. Furthermore, the results highlight that our solution outperforms in terms of true positive rate and false positive rate existing techniques reported in the literature.
Autors: Juliette Dromard;Gilles Roudière;Philippe Owezarski;
Appeared in: IEEE Transactions on Network and Service Management
Publication date: Mar 2017, volume: 14, issue:1, pages: 34 - 47
Publisher: IEEE
 
» Online Bimanual Manipulation Using Surface Electromyography and Incremental Learning
Abstract:
The paradigm of simultaneous and proportional myocontrol of hand prostheses is gaining momentum in the rehabilitation robotics community. As opposed to the traditional surface electromyography classification schema, in simultaneous and proportional control the desired force/torque at each degree of freedom of the hand/wrist is predicted in real-time, giving to the individual a more natural experience, reducing the cognitive effort and improving his dexterity in daily-life activities. In this study we apply such an approach in a realistic manipulation scenario, using 10 non-linear incremental regression machines to predict the desired torques for each motor of two robotic hands. The prediction is enforced using two sets of surface electromyography electrodes and an incremental, non-linear machine learning technique called Incremental Ridge Regression with Random Fourier Features. Nine able-bodied subjects were engaged in a functional test with the aim to evaluate the performance of the system. The robotic hands were mounted on two hand/wrist orthopedic splints worn by healthy subjects and controlled online. An average completion rate of more than 95% was achieved in single-handed tasks and 84% in bimanual tasks. On average, 5 min of retraining were necessary on a total session duration of about 1 h and 40 min. This work sets a beginning in the study of bimanual manipulation with prostheses and will be carried on through experiments in unilateral and bilateral upper limb amputees thus increasing its scientific value.
Autors: Ilaria Strazzulla;Markus Nowak;Marco Controzzi;Christian Cipriani;Claudio Castellini;
Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Publication date: Mar 2017, volume: 25, issue:3, pages: 227 - 234
Publisher: IEEE
 
» Online Broadband Insulation Spectroscopy of Induction Machines Using Signal Injection
Abstract:
The breakdown of the stator insulation is one of the main causes of failure in medium- and high-voltage ac machines. Even though there are several techniques available to detect the failure of the ground-wall insulation and the turn insulation, there are only few online techniques to detect the deterioration of the insulation prior to its breakdown. Established methods, like the partial discharge analysis or the capacitance and dissipation factor test that can be applied to monitor the insulation health online, are limited to assessing the condition of the ground-wall insulation. An attempt has been made to evaluate a different technique that might be used to monitor the ground-wall insulation, as well as the turn insulation condition, which is based on the broadband impedance spectroscopy of the motor. Insulation aging will change the resistance and capacitance of the ground-wall insulation, as well as the turn insulation. These changes in the insulation parameters are reflected in changes of the phase-to-ground impedance of the motor. This can be used to monitor the condition of the insulation. To exploit the relationship between the phase-to-ground impedance and the insulation parameters, for a given temperature, a signal injection-based technique is proposed to measure the impedance of stator insulation on an operating machine and trend the response over time. The basic concept for the signal injection is introduced and measurements on different machine classes (480 and 4160 V) are presented to show the feasibility of the method.
Autors: Prabhakar Neti;Stefan Grubic;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Mar 2017, volume: 53, issue:2, pages: 1054 - 1062
Publisher: IEEE
 
» Online Coded Caching With Random Access
Abstract:
In this letter, we consider a caching network with two characteristics: first, the operations of users’ caches have to be performed on the fly, and second, each user has access to the system with a known probability. Particularly, we intend to characterize approximately the optimal long-term average rate of the shared link. By utilizing the knowledge of eviction in the server and applying the technique of coded caching to the active users in each time, we propose and analyze a new scheme called coded outdated file eviction for random access (coded OER). Furthermore, we present a tight upper bound on the performance of the proposed coded OER scheme and prove that it is approximately optimal.
Autors: Qifa Yan;Udaya Parampalli;Xiaohu Tang;Qingchun Chen;
Appeared in: IEEE Communications Letters
Publication date: Mar 2017, volume: 21, issue:3, pages: 552 - 555
Publisher: IEEE
 
» Online Continuous Measurement of the Operating Deflection Shape of Power Transmission Belts Through Electrostatic Charge Sensing
Abstract:
The measurement of the operating deflection shape (ODS) of power transmission belts is of great importance for the fault diagnosis and prognosis of industrial belt drive systems. This paper presents a novel method based on an electrostatic sensor array to measure the ODS of a belt moving both axially and transversely. The electrostatic sensor integrates a charge amplifier that converts the induced charge on a strip-shaped electrode into a voltage signal. Finite-element simulations are performed to study the sensing characteristics of the sensor and the results reveal that the sensor can respond to vibration displacement. Construction of the ODS is achieved in the frequency domain using the ODS frequency response function. Comparative experimental studies with a high-accuracy laser displacement sensor were conducted on a purpose-built test rig and the results show that the vibration frequencies and their relative magnitudes obtained from both sensors agree well with each other. Experiments conducted over a range of belt axial speeds show that the belt vibrates at frequencies that are well separated and identifiable using a peak picking method. The measured ODSs of the first three vibration modes illustrate that the vibration displacement is larger in the middle of the belt span than at both ends and that the phase shift relative to the reference sensor at each measurement point increases monotonically along the belt running direction. The belt axial speed determines the vibration frequencies and displacement, which reaches the maximum amplitude around the natural frequency of the belt.
Autors: Yonghui Hu;Yong Yan;Lu Yang;Lijuan Wang;Xiangchen Qian;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Mar 2017, volume: 66, issue:3, pages: 492 - 501
Publisher: IEEE
 
» Online Human Interaction Detection and Recognition With Multiple Cameras
Abstract:
We address the problem of detecting and recognizing online the occurrence of human interactions as seen by a network of multiple cameras. We represent interactions by forming temporal trajectories, coupling together the body motion of each individual and their proximity relationships with others, and also sound whenever available. Such trajectories are modeled with kernel state-space (KSS) models. Their advantage is being suitable for the online interaction detection, recognition, and also for fusing information from multiple cameras, while enabling a fast implementation based on online recursive updates. For recognition, in order to compare interaction trajectories in the space of KSS models, we design so-called pairwise kernels with a special symmetry. For detection, we exploit the geometry of linear operators in Hilbert space, and extend to KSS models the concept of parity space, originally defined for linear models. For fusion, we combine KSS models with kernel construction and multiview learning techniques. We extensively evaluate the approach on four single view publicly available data sets, and we also introduce, and will make public, a new challenging human interactions data set that we have collected using a network of three cameras. The results show that the approach holds promise to become an effective building block for the analysis of real-time human behavior from multiple cameras.
Autors: Saeid Motiian;Farzad Siyahjani;Ranya Almohsen;Gianfranco Doretto;
Appeared in: IEEE Transactions on Circuits and Systems for Video Technology
Publication date: Mar 2017, volume: 27, issue:3, pages: 649 - 663
Publisher: IEEE
 
» Online Multiparameter Identification of Surface-Mounted PMSM Considering Inverter Disturbance Voltage
Abstract:
The disturbance voltage of voltage-source inverter operation exerts significant influences on the accuracy of motor parameter identification. In this paper, an accurate model is established for estimating the disturbance voltage that includes current harmonics and their derivative. The conclusion is drawn that the derivative of the d -axis current harmonics plays a major role in causing estimation error of the disturbance voltage. Based on this, two methods are proposed to reduce the estimation error of the disturbance voltage. One employs an iterative learning controller in the d-axis current control loop to suppress the harmonics of d-axis current, thus reducing their influence on the estimation of the disturbance voltage. The second estimates the disturbance voltage on the basis of the average value of the variables in q-axis equation of the motor, so that the estimation result is immune to current harmonics. Motor parameter identification accuracy is consequently improved by both.
Autors: Weitao Deng;Changliang Xia;Yan Yan;Qiang Geng;Tingna Shi;
Appeared in: IEEE Transactions on Energy Conversion
Publication date: Mar 2017, volume: 32, issue:1, pages: 202 - 212
Publisher: IEEE
 
» Online Parameter Identification of Lithium-Ion Batteries With Surface Temperature Variations
Abstract:
In this paper, an adaptive parameter identification technique is proposed for lithium-ion batteries. The proposed strategy capitalizes on the power of adaptive control theory to attain robustness to parameter variation. Therefore, accurate state-of-charge (SOC) and state-of-health (SOH) estimation is obtained since they are directly correlated to the battery's parameters. Unlike many estimation procedures, the proposed estimator's convergence and stability are guaranteed by Lyapunov's direct method. In addition, temperature variations introduce a drift on the battery's parameters, which reduces the estimation accuracy. Therefore, a postcompensation methodology is proposed using surface temperature to cope with these effects. The effectiveness of the proposed estimation scheme is validated through a set of experiments under different temperatures.
Autors: Hicham Chaoui;Asmae El Mejdoubi;Hamid Gualous;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Mar 2017, volume: 66, issue:3, pages: 2000 - 2009
Publisher: IEEE
 
» Online Scheme for Multiple Camera Multiple Target Tracking Based on Multiple Hypothesis Tracking
Abstract:
We propose an online tracking algorithm for multiple target tracking with multiple cameras. In this paper, we suggest a multiple hypothesis tracking (MHT) framework to find an unknown number of multiple tracks through the spatio-temporal association between tracklets generated from multiple cameras. In this framework, the MHT is realized online by solving the maximum weighted clique problem (MWCP) at every frame to estimate the 3D trajectories of the targets. To handle the NP-hard issue of the MWCP, we propose a novel online scheme that formulates the MWCP using feedback information from the previous frame’s result to find optimal tracks at every frame. This scheme enables the MWCP to be formulated by multiple subproblems and will significantly reduce the computation. The experiments show that the proposed algorithm performs comparably with the state-of-the-art batch algorithms, even though it adopts an online scheme.
Autors: Haanju Yoo;Kikyung Kim;Moonsub Byeon;Younghan Jeon;Jin Young Choi;
Appeared in: IEEE Transactions on Circuits and Systems for Video Technology
Publication date: Mar 2017, volume: 27, issue:3, pages: 454 - 469
Publisher: IEEE
 
» Online Variable Coding Length Product Quantization for Fast Nearest Neighbor Search in Mobile Retrieval
Abstract:
Quantization methods are crucial for efficient nearest neighbor search in many applications such as image, music, or product search. As mobile devices are becoming increasingly more popular, the quantization methods on mobile devices are more important, because a large portion of the search queries are becoming performed on mobile devices. One important characteristic of the communication on mobile devices is the inherent unreliability of their communication channels. In order to adapt the quality changes of the communication channels, we need to change the coding length of the quantization accordingly. The existing quantization methods use fixed-length codebooks, and it is expensive to retrain another codebook with different coding length. In this paper, we propose a novel variable length product quantization framework that consists of a set of fast universal scalar quantizers. The framework is capable of producing variable length quantization without retraining the codebook. Each data vector is transformed into a new space to reduce the correlation across dimensions. A proper number of bits is allocated to represent the scalar component in each dimension according to the given coding length. For each component, we estimate its probability density function (PDF) and design an efficient universal scalar quantizer based on the PDF and the allocated bits. To reduce distortion, we learn a Gaussian mixture model for the data. The experimental results show that, compared to state-of-the-art product quantization methods, our approach can construct the codebooks online for variable coding lengths and achieve the comparable performance.
Autors: Jin Li;Xuguang Lan;Xiangwei Li;Jiang Wang;Nanning Zheng;Ying Wu;
Appeared in: IEEE Transactions on Multimedia
Publication date: Mar 2017, volume: 19, issue:3, pages: 559 - 570
Publisher: IEEE
 
» Only-One-Victor Pattern Learning in Computer Go
Abstract:
Automatically acquiring domain knowledge from professional game records, a kind of pattern learning, is an attractive and challenging issue in computer Go. This paper proposes a supervised learning method, by introducing a new generalized Bradley-Terry model, named Only-One-Victor, to learn patterns from game records. Basically, our algorithm applies the same idea with Elo rating algorithm, which considers each move in game records as a group of move patterns, and the selected move as the winner of a kind of competition among all groups on current board. However, being different from the generalized Bradley-Terry model for group competition used in Elo rating algorithm, Only-One-Victor model in our work simulates the process of making selection from a set of possible candidates by considering such process as a group of independent pairwise comparisons. We use a graph theory model to prove the correctness of Only-One-Victor model. In addition, we also apply the Minorization-Maximization (MM) to solve the optimization task. Therefore, our algorithm still enjoys many computational advantages of Elo rating algorithm, such as the scalability with high dimensional feature space. With the training set containing 115,832 moves and the same feature setting, the results of our experiments show that Only-One-Victor outperforms Elo rating, a well-known best supervised pattern learning method.
Autors: Jiao Wang;Chenjun Xiao;Tan Zhu;Chu-Husan Hsueh;Wen-Jie Tseng;I-Chen Wu;
Appeared in: IEEE Transactions on Computational Intelligence and AI in Games
Publication date: Mar 2017, volume: 9, issue:1, pages: 88 - 102
Publisher: IEEE
 
» Open Symphony: Creative Participation for Audiences of Live Music Performances
Abstract:
Most contemporary Western performing arts practices restrict creative interactions from audiences. Open Symphony is designed to explore audience-performer interaction in live music performances, assisted by digital technology. Audiences can conduct improvising performers by voting for various musical "modes." Technological components include a web-based mobile application, a visual client displaying generated symbolic scores, and a server service for the exchange of creative data. The interaction model, app, and visualization were designed through an iterative participatory design process. The system was experienced by about 120 audience and performer participants (35 completed surveys) in controlled (lab) and real-world settings. Feedback on usability and user experience was overall positive, and live interactions demonstrate significant levels of audience creative engagement. The authors identified further design challenges around audience sense of control, learnability, and compositional structure. This article is part of a special issue on multimedia for enriched music.
Autors: Yongmeng Wu;Leshao Zhang;Nick Bryan-Kinns;Mathieu Barthet;
Appeared in: IEEE Multimedia
Publication date: Mar 2017, volume: 24, issue:1, pages: 48 - 62
Publisher: IEEE
 
» Open-Source and Widely Disseminated Robot Hardware [From the Guest Editors]
Abstract:
The articles in this special section focus on the open-source movement taking over the robotics industry. Open source systems have already revolutionized a number of industries by empowering end users to contribute to the products that they need and want and by fueling grass-roots development and continual improvement of projects in completely new areas. While there have been innumerable successes in software and electronics hardware, open mechanical hardware is taking longer to catch on. There are a number of likely reasons for this, including the complexity, expense, and time associated with fabricating mechanical components as well as the challenge and reliability of assembling the wide range of mechanical and electronic components required to produce a fully functional system. In comparison with open-source software efforts, open hardware has numerous additional practical challenges associated with dissemination and evolution of the product driven by end users. However, rapid fabrication technologies have improved to the point of being able to produce parts that are strong, robust, and precise enough for practical robotic systems, and the pricing of the systems and supplies have lowered to the point that many of these machines are available in fabrication facilities at most universities.
Autors: Aaron Dollar;Francesco Mondada;Alberto Rodriguez;Giorgio Metta;
Appeared in: IEEE Robotics & Automation Magazine
Publication date: Mar 2017, volume: 24, issue:1, pages: 30 - 31
Publisher: IEEE
 
» Operating Point Resolved Loss Calculation Approach in Saturated Induction Machines
Abstract:
In this paper, the global operating point dependent losses of induction machines are studied by using a local transient loss formulation. The level of flux, the machine is operated at, depends on the operation mode of the inverter. Hence, for precise loss modeling of inverter driven induction machines at the machine design stage, the time and spatial distribution of flux density and the influence of choosing the best operating point is included. A loss scaling method is developed to map iron losses calculated at a single synchronous frequency to other frequencies along the torque–speed map. The modeled losses and operating points are compared to extensive machine measurements. By way of example, the effect of different electrical steel grades tailored either to low losses or preferable magnetizability on the machine performance is investigated.
Autors: Georg Von Pfingsten;Simon Steentjes;Kay Hameyer;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Mar 2017, volume: 64, issue:3, pages: 2538 - 2546
Publisher: IEEE
 
» Operating Principles, Design Considerations, and Experimental Characteristics of High-Voltage 4H-SiC Bidirectional IGBTs
Abstract:
Bidirectional power transistors are essential components of several power electronics systems, such as matrix converters. In this paper, we present the operating principles, design considerations, and experimental characteristics of a novel planar gate 4H-SiC bidirectional insulated gate bipolar transistors. The impact of various drift layer and unit cell parameters on blocking, on-state, and switching performance has been evaluated by using numerical simulations, and critical performance tradeoffs have been discussed. Based on the optimized design, devices were fabricated on lightly doped free-standing n-type 4H-SiC wafers. Fabricated devices showed good conductivity modulation, with a forward voltage drop of 9.7 V at 50 A/cm2 at room temperature, which increased to 11.5 V at 150 °C.
Autors: Sauvik Chowdhury;Collin W. Hitchcock;Zachary Stum;Rajendra P. Dahal;Ishwara B. Bhat;T. Paul Chow;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Mar 2017, volume: 64, issue:3, pages: 888 - 896
Publisher: IEEE
 
» Operational Risk Metric for Dynamic Security Assessment of Renewable Generation
Abstract:
The objective of this paper is to explore the efficacy of applying risk-based security assessment (RBSA) to define reliability standards for electricity grids with high penetration of converter-interfaced generation. A novel approach to estimate the impact of transient instability is presented in this paper by modeling several important protection systems in the transient stability analysis. In addition, a probabilistic model is developed to capture the uncertainty of increased converter-interfaced renewable penetration. A synthetic test case is derived from a realistic power system to verify the proposed method. The simulation results show that RBSA not only provides significantly relaxed security limits, but also helps in identifying critical aspects of system reliability that are not possible using conventional deterministic methods.
Autors: Sohom Datta;Vijay Vittal;
Appeared in: IEEE Transactions on Power Systems
Publication date: Mar 2017, volume: 32, issue:2, pages: 1389 - 1399
Publisher: IEEE
 
» Operational Shock Analysis for 2.5-in Multi-Disk HDD Considering Ramp–Disk Gap Irregularity
Abstract:
With an increased mobility, hard disk drives (HDDs) now use ramp load/unload technology, and multiple disks are used to increase the data capacity. This can result in contact between the ramp and the disks, which negatively affects the slider dynamics under operational shock conditions. There are several types of ramp–disk contact, such as simultaneous, successive, and single contact, and these depend on the distance between the ramp and each disk in a multi-disk HDD. This paper examines the effect of ramp–disk contact on the slider dynamics using a transient shock analysis. The ramp–disk contact affects the head stack assembly bending mode and slider dynamics. The effect of irregular gaps between the disks and adjacent ramp on the slider dynamics is analyzed with the ramp–disk contact force. The simulation shows that the gap irregularity between the ramp and each disk should be as small as possible to improve the stability of the slider dynamics.
Autors: Joo Young Yoon;Jonghak Choi;Geonyun Lim;No-Cheol Park;Young-Pil Park;Kyoung-Su Park;Minjae Kim;
Appeared in: IEEE Transactions on Magnetics
Publication date: Mar 2017, volume: 53, issue:3, pages: 1 - 4
Publisher: IEEE
 
» Opponent Modeling by Expectation–Maximization and Sequence Prediction in Simplified Poker
Abstract:
We consider the problem of learning an effective strategy online in a hidden information game against an opponent with a changing strategy. We want to model and exploit the opponent and make three proposals to do this; first, to infer its hidden information using an expectation–maximization (EM) algorithm; second, to predict its actions using a sequence prediction method; and third, to simulate games between our agent and our opponent model in-between games against the opponent. Our approach does not require knowledge outside the rules of the game, and does not assume that the opponent’s strategy is stationary. Experiments in simplified poker games show that it increases the average payoff per game of a state-of-the-art no-regret learning algorithm.
Autors: Richard Mealing;Jonathan L. Shapiro;
Appeared in: IEEE Transactions on Computational Intelligence and AI in Games
Publication date: Mar 2017, volume: 9, issue:1, pages: 11 - 24
Publisher: IEEE
 
» Opportunistic Downlink Interference Alignment for Multi-Cell MIMO Networks
Abstract:
In this paper, we propose an opportunistic downlink interference alignment (ODIA) for interference-limited cellular downlink, which intelligently combines user scheduling and downlink IA techniques. The proposed ODIA not only efficiently reduces the effect of inter-cell interference from other-cell base stations (BSs) but also eliminates intra-cell interference among spatial streams in the same cell. We show that the minimum number of users required to achieve a target degrees-of-freedom can be fundamentally reduced, i.e., the fundamental user scaling law can be improved by using the ODIA, compared with the existing downlink IA schemes. In addition, we adopt a limited feedback strategy in the ODIA framework, and then analyze the number of feedback bits required for the system with limited feedback to achieve the same user scaling law of the ODIA as the system with perfect channel state information. We also modify the original ODIA in order to further improve the sum-rate, which achieves the optimal multiuser diversity gain, i.e., , per spatial stream even in the presence of downlink inter-cell interference, where denotes the number of users in a cell. Simulation results show that the ODIA significantly outperforms existing interference management techniques in terms of sum rate in realistic cellular environments. Note that the ODIA operates in a non-collaborative and decoupled manner, i.e., it requires no information exchange among BSs and no iterative beamformer optimization between BSs and users, thus leading to an easier implementation.
Autors: Hyun Jong Yang;Won-Yong Shin;Bang Chul Jung;Changho Suh;Arogyaswami Paulraj;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Mar 2017, volume: 16, issue:3, pages: 1533 - 1548
Publisher: IEEE
 
» Opportunistic Image Acquisition of Individual and Group Activities in a Distributed Camera Network
Abstract:
The decreasing cost and size of video sensors has led to camera networks becoming pervasive in our lives. However, the ability to analyze these images effectively is very much a function of the quality of the acquired images. In this paper, we consider the problem of automatically controlling the fields of view of individual pan–tilt–zoom (PTZ) cameras in a camera network leading to improved situation awareness (e.g., where and what are the critical targets and events) in a region of interest. The network of cameras attempts to observe the entire region of interest at some minimum resolution while opportunistically acquiring high resolution images of critical events in real time. Since many activities involve groups of people interacting, an important decision that the network needs to make is whether to focus on individuals or groups of them. This is achieved by understanding the performance of video analysis tasks and designing camera control strategies to improve a metric that quantifies the quality of the source imagery. Optimization strategies, along with a distributed implementation, are proposed, and their theoretical properties analyzed. The proposed methods bring together computer vision and network control ideas. The performance of the proposed methodologies discussed herein has been evaluated on a real-life wireless network of PTZ capable cameras.
Autors: Chong Ding;Jawadul H. Bappy;Jay A. Farrell;Amit K. Roy-Chowdhury;
Appeared in: IEEE Transactions on Circuits and Systems for Video Technology
Publication date: Mar 2017, volume: 27, issue:3, pages: 664 - 672
Publisher: IEEE
 
» Opportunities and Challenges of Trip Generation Data Collection Techniques Using Cellular Networks
Abstract:
We are witnessing how urban areas are reclaiming road space, before devoted exclusively to cars, for pedestrians. With the increase of pedestrian activity, we need to update our existing transportation forecasting models by focusing more on people walking. The first step of extending the current models is to start with collecting information on pedestrians needed for the trip generation phase. This article discusses opportunities and limitations of tracking pedestrian activity by utilizing information provided by cellular networks. In order to track people, regardless of the underlying wireless media, two qualifications must be met: first, unique and anonymous identification, and second, geospatial visibility through time. While the latter requirement can be achieved with techniques that are similar for different wireless media, how to uniquely identify a pedestrian using a cellular network is domain-specific. We show that tracking of pedestrians using cellular networks can be done not only without their constant active participation, but also without disrupting normal cellular service. However, although this method is technically feasible, one should be very careful when wanting to implement it by keeping in mind a very important thing: how to protect people's privacy.
Autors: Iva Bojic;Yuji Yoshimura;Carlo Ratti;
Appeared in: IEEE Communications Magazine
Publication date: Mar 2017, volume: 55, issue:3, pages: 204 - 209
Publisher: IEEE
 
» Optical Remote Sensor Calibration Using Micromachined Multiplexing Optical Focal Planes
Abstract:
Traditional calibration approaches for optical remote sensor are based on single-pixel illumination through collimated light using measuring angles. However, the vibration of rotating turntable and accuracy of angle measurement affect the calibration accuracy. In this paper, we propose a new geometrical calibration approach with micromachined multiplexing optical focal plane (MOFP) combined with a collimating device for optical remote sensor. A micromachined procedure is used to manufacture an MOFP using the optimized aperture size. The MOFP, which can produce only one image with multiple diffraction points to calibrate the interior parameters of optical remote senor, is applied as collimated light splitters. Experiments show that this method is sufficient and can be used particularly in ground applications, as well as, in principle, on-orbit calibration.
Autors: Jin Li;Fengdeng Liu;Si Liu;Zhengjun Wang;
Appeared in: IEEE Sensors Journal
Publication date: Mar 2017, volume: 17, issue:6, pages: 1663 - 1672
Publisher: IEEE
 
» Optical Submicrometer Displacement Sensor Based on the Herriot Cell
Abstract:
In this paper, we present a displacement sensor using a Herriott cell designed with the cylindrical deformable mirrors. A movable object modifies one of the mirror’s curvature and position in the cell, thus changing the angular path of the output beam that is measured with the knife edge technique. The design results in a compact device with easy manufacturing process for the mirrors. We achieve a sensitivity of over the range of with a precision of . The use of a Herriott cell to measure displacements allows the modification of the sensitivity and range of the sensor according to the number of incidences.
Autors: Juan José Campos-Puebla;Celia Sánchez-Pérez;Víctor Argueta-Díaz;
Appeared in: IEEE Sensors Journal
Publication date: Mar 2017, volume: 17, issue:6, pages: 1715 - 1720
Publisher: IEEE
 
» Optimal Bidding in Performance-Based Regulation Markets: An MPEC Analysis With System Dynamics
Abstract:
In this paper, we address the problem of optimal bidding in performance-based regulation markets for a large price-maker regulation resource. Focusing on the case of the California Independent System Operator (ISO), detailed market components are considered, such as regulation capacity payment, regulation mileage payment, performance accuracy adjustment, automatic generation control dispatch, and participation factor. Our analysis also incorporates system dynamics of the regulation resource for different resource types and technologies. In principle, our problem formulation is a mathematical program with equilibrium constraints (MPEC). However, our fundamentally new formulations introduce several new challenges in solving the MPEC problem in the context of performance-based regulation markets that are not previously addressed. In fact, global optimization techniques fail to solve the original nonlinear program due to its complexity. Therefore, we undergo several innovative steps to transform the problem into a mixed-integer linear program which is solved with accuracy, reliability, and computational efficiency. Insightful case studies are presented using data from a California ISO regulation market project.
Autors: Ashkan Sadeghi-Mobarakeh;Hamed Mohsenian-Rad;
Appeared in: IEEE Transactions on Power Systems
Publication date: Mar 2017, volume: 32, issue:2, pages: 1282 - 1292
Publisher: IEEE
 
» Optimal Camera Placement for Motion Capture Systems
Abstract:
Optical motion capture is based on estimating the three-dimensional positions of markers by triangulation from multiple cameras. Successful performance depends on points being visible from at least two cameras and on the accuracy of the triangulation. Triangulation accuracy is strongly related to the positions and orientations of the cameras. Thus, the configuration of the camera network has a critical impact on performance. A poor camera configuration may result in a low quality three-dimensional (3D) estimation and consequently low quality of tracking. This paper introduces and compares two methods for camera placement. The first method is based on a metric that computes target point visibility in the presence of dynamic occlusion from cameras with “good” views. The second method is based on the distribution of views of target points. Efficient algorithms, based on simulated annealing, are introduced for estimating the optimal configuration of cameras for the two metrics and a given distribution of target points. The accuracy and robustness of the algorithms are evaluated through both simulation and empirical measurement. Implementations of the two methods are available for download as tools for the community.
Autors: Pooya Rahimian;Joseph K. Kearney;
Appeared in: IEEE Transactions on Visualization and Computer Graphics
Publication date: Mar 2017, volume: 23, issue:3, pages: 1209 - 1221
Publisher: IEEE
 
» Optimal Content Prefetching in NDN Vehicle-to-Infrastructure Scenario
Abstract:
Data replication and in-network storage are two basic principles of the information-centric networking (ICN) framework in which caches spread out in the network can be used to store the most popular contents. This paper shows how one of the ICN architectures, i.e., Named Data Networking (NDN), with content prefetching can maximize the probability that a user retrieves the desired content in a vehicle-to-infrastructure scenario. We give an integer linear programming formulation of the problem of optimally distributing content in the network nodes while accounting for the available storage capacity and the available link capacity. The optimization framework is then leveraged to evaluate the impact on content retrievability of topology- and network-related parameters as the number and mobility models of moving users, the size of the content catalog, and the location of the available caches. Moreover, we show how the proposed model can be modified to find the minimum storage occupancy to achieve a given content retrievability level. The results obtained from the optimization model are finally validated against an NDN architecture through simulations in ndnSIM.
Autors: Giulia Mauri;Mario Gerla;Federico Bruno;Matteo Cesana;Giacomo Verticale;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Mar 2017, volume: 66, issue:3, pages: 2513 - 2525
Publisher: IEEE
 
» Optimal Design and Simulation of Sensor Arrays for Solar Motion Estimation
Abstract:
Modern sensors consist of arrays of detectors specially arranged to enhance precision, capabilities, and field of view (FOV). Sensor arrays can have multiple functionalities, such as the simultaneous detection of position and motion. We use a linear sensor model and develop an optimization method to design an array of photodiodes. Our objective function minimizes bias and variance estimations. We introduce a maximum likelihood technique to approximate and determine the bias caused by measurement errors, and verify our theory by statistically complete simulations. We apply our theory to design an optimal sun sensor. The sensor has a predefined conical FOV, and its accuracy is controlled by a set of directionally variable weighting parameters. This enables us to compute the optimal placements of photodiodes under various operational conditions. It is found that for a uniform accuracy distribution, both the variance and bias estimations can be exactly minimized for a given array configuration. For non-uniform accuracy distributions with rotational symmetries, when a higher accuracy is required around the centerline of the FOV, both errors attain their minima when the array configuration becomes inclined toward the center. In non-uniform and non-axisymmetric distributions, when a higher accuracy is imposed along a line or a path, the bias and variance errors differ significantly, while the variance minimization implies the concentration of the cells toward the path, the bias minimization yields a uniform distribution. The method presented in this paper can be used in the optimal design of sun sensors for space systems and solar power plants.
Autors: Peyman Yousefian;Mohammad Durali;Mir Abbas Jalali;
Appeared in: IEEE Sensors Journal
Publication date: Mar 2017, volume: 17, issue:6, pages: 1673 - 1680
Publisher: IEEE
 
» Optimal Design of New Cascaded Switch-Ladder Multilevel Inverter Structure
Abstract:
In this paper, a new cascade switch-ladder multilevel inverter topology is presented which can generate a large number of output voltage levels. First, a fundamental switch-ladder multilevel inverter structure is described. Then, the structure of recommended cascade topology based on series connection of fundamental switch-ladder topologies is presented. To generate maximum number of levels with minimum number of switching elements, dc sources, and voltage on switches, the proposed cascade topology is optimized. Comparison results prove that the presented cascade topology requires fewer numbers of components. Also, the value of voltage rating on switches is less than other structures. Experimental results for two topologies are analyzed to verify the performance of the proposed topology.
Autors: Rasoul Shalchi Alishah;Seyed Hossein Hosseini;Ebrahim Babaei;Mehran Sabahi;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Mar 2017, volume: 64, issue:3, pages: 2072 - 2080
Publisher: IEEE
 
» Optimal Input and Quantization Interval for Quantized Feedback System With Variable Quantizer
Abstract:
Networked control systems (NCSs) have received much attention in the field of robot teleoperation, telesurgery, and other applications. In an NCS, it is important to compress data transmitted over a limited communication network while preserving the data required for control. We address a quantized feedback system in which the output of a plant is quantized with a variable quantization interval. For such a system, we present a novel optimal quantized feedback control. The proposed approach derives not only an optimal input, but also an optimal quantization interval in the quantizer simultaneously using the model predictive control. The approach also satisfies constraints on the state, input, and quantization interval. The effectiveness of the proposed approach is validated through cart-positioning experiments.
Autors: Tadanao Zanma;Makoto Azegami;Kang-Zhi Liu;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Mar 2017, volume: 64, issue:3, pages: 2246 - 2254
Publisher: IEEE
 
» Optimal Joint Power and Subcarrier Allocation for Full-Duplex Multicarrier Non-Orthogonal Multiple Access Systems
Abstract:
In this paper, we investigate resource allocation algorithm design for multicarrier non-orthogonal multiple access (MC-NOMA) systems employing a full-duplex (FD) base station for serving multiple half-duplex (HD) downlink and uplink users simultaneously. The proposed algorithm is obtained from the solution of a non-convex optimization problem for the maximization of the weighted sum system throughput. We apply monotonic optimization to develop an optimal joint power and subcarrier allocation policy. The optimal resource allocation policy serves as a system performance benchmark due to its high computational complexity. Furthermore, a suboptimal iterative scheme based on successive convex approximation is proposed to strike a balance between computational complexity and optimality. Our simulation results reveal that the proposed suboptimal algorithm achieves a close-to-optimal performance. In addition, FD MC-NOMA systems employing the proposed resource allocation algorithms provide a substantial system throughput improvement compared with conventional HD multicarrier orthogonal multiple access (MC-OMA) systems and other baseline schemes. In addition, our results unveil that FD MC-NOMA systems enable a fairer resource allocation compared with traditional HD MC-OMA systems.
Autors: Yan Sun;Derrick Wing Kwan Ng;Zhiguo Ding;Robert Schober;
Appeared in: IEEE Transactions on Communications
Publication date: Mar 2017, volume: 65, issue:3, pages: 1077 - 1091
Publisher: IEEE
 
» Optimal Periodic Inspections and Activation Sequencing Policy in Standby Systems With Condition-Based Mode Transfer
Abstract:
This paper models a hybrid standby system subject to periodic inspections and condition-based standby mode transfers during a mission. At the beginning of the mission only one element is online and operating. The second element waits in a hot standby mode being ready to replace the failed online element at any time. Other elements wait in less-stressful and less-costly warm standby mode. During the mission periodic inspections are performed for checking conditions of the online and hot standby elements and subsequently triggering necessary mode transfer(s) of available warm standby element(s) to replace the failed hot standby element and/or online element. We suggest an efficient numerical method to assess availability and expected total mission cost (including standby cost, operation cost and mode transfer cost of system elements, inspection cost, system interruption or idle cost) of the considered system. The algorithm is flexible and applicable to arbitrary type of time-to-failure distributions. Then we formulate and solve new optimization problems that identify the optimal combination of inter-inspection interval and element activation sequence to minimize expected total mission cost while satisfying a certain constraint on system availability. As illustrated through examples, the optimization results can facilitate cost-effective and availability-aware planning of system inspection and operation.
Autors: Yuanshun Dai;Gregory Levitin;Liudong Xing;
Appeared in: IEEE Transactions on Reliability
Publication date: Mar 2017, volume: 66, issue:1, pages: 189 - 201
Publisher: IEEE
 
» Optimal Power Allocation in Spatial Modulation Systems
Abstract:
In spatial modulation (SM) systems, when channel state information is available at the transmitter, adaptive power allocation can be exploited to enhance the SM performance. In this paper, optimal power allocation in SM systems is considered from an information-theoretical view. First, as there is no closed-form expression of the SM capacity, the instantaneous mutual information is formulated in an analytic form for SM systems with two transmit antennas. Then, two power-allocation algorithms are proposed to maximize the SM mutual information. One is a sub-optimal power-allocation algorithm that is established in closed form to maximize the upper bound of SM mutual information. The other is an iterative algorithm for optimal power allocation that is proposed to achieve the maximum mutual information of SM systems while dramatically reducing the operational complexity compared with global computer searching. To evaluate the performance of the proposed power-allocation algorithms, numerical and simulation results are reported in terms of outage capacity and ergodic capacity, which demonstrates that the proposed power-allocation algorithms significantly improve the SM performance, compared with conventional equal-power allocation.
Autors: Yabo Shi;Meng Ma;Yuli Yang;Bingli Jiao;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Mar 2017, volume: 16, issue:3, pages: 1646 - 1655
Publisher: IEEE
 
» Optimal Pulse Transmission Criterion and Its Application to Pulse Networks Design
Abstract:
A criterion of optimal pulse transmission (OPT) for the design of pulse or ultra-wideband (UWB) networks is presented. The OPT is achieved when the normalized Euclid distance (NED) of the outgoing signal and the excitation signal arrives at its minimum, and thus, it comprehensively takes the shape distortion as well as the amplitude modification into account. Consequently, it can be regarded as a generalization of the traditional amplitude-oriented maximum power transmission (MPT) criterion for the sinusoidal or narrowband networks to the pulse or UWB cases. A matching network is provided as an example for giving more insight into the OPT criterion and its usage. For a Gaussian input pulse ranging from dc to 20 GHz, the fidelity and NED are 0.8871 and 0.5189 for the network designed using the OPT criterion. The simulated and measured results demonstrate the features and advantages of the OPT criterion compared with the MPT criterion.
Autors: Shunli Li;Xiaoxing Yin;Hongxin Zhao;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Mar 2017, volume: 27, issue:3, pages: 233 - 235
Publisher: IEEE
 
» Optimal Resource Allocation for Packet Delay Minimization in Multi-Layer UAV Networks
Abstract:
Research and development of heterogeneous small cell in cellular network accommodates the proliferation of data-hungry devices and applications. Meanwhile, for challenges in providing high-data-rate transmission in poor coverage area, utilizing unmanned aerial vehicles (UAVs) provides a promising solution attracting tremendous attention. However, tight integration of UAVs creates an obstruction in existing network to acquire high efficient resource utilization, which needs investigation in 3 D network architecture. In this letter, we propose a resource allocation optimization mechanism to minimize mean packet transmission delay in 3 D cellular network with multi-layer UAVs. Numerical results demonstrate effectiveness of the proposed algorithm, where optimal spectrum and power allocation can provide minimum packet transmission delay.
Autors: Jin Li;Youngnam Han;
Appeared in: IEEE Communications Letters
Publication date: Mar 2017, volume: 21, issue:3, pages: 580 - 583
Publisher: IEEE
 
» Optimal RTO Timer for Best Transmission Efficiency of DTN Protocol in Deep-Space Vehicle Communications
Abstract:
The delay/disruption-tolerant network (DTN) was proposed as an end-to-end networking architecture for file delivery service in a stressed communication environment. A typical application of DTN technology is for reliable data delivery in deep-space vehicle communications. The main protocol of DTN, i.e., bundle protocol (BP), utilizes a store-and-forward mechanism and a custody transfer option for transmission reliability. However, little work has been done on the performance evaluation of DTN's BP in deep-space communications. In this paper, we present a study of the retransmission timeout (RTO) timer setting for the use of BP for reliable file (or data) transmission over a relay-based deep-space vehicle communication infrastructure characterized by extremely long latency, lossy data links, and highly asymmetric channel rates. Unlike most studies proposed for terrestrial Internet for which the RTO timer is set equal to or longer than the round-trip time (RTT), we propose to set the RTO timer shorter than the RTT and expect that it will increase delivery efficiency per unit of time. We intend to find an RTO timer setting for maximum data delivery performance of BP, which is considered to be an optimal RTO timer, for deep-space missions. For the first time, analytical models are built for delivery performance involving the RTO timer. Using the built models, we tune the RTO timer toward the highest data delivery performance. The models are validated by running text file transfer experiments using a PC-based testbed and tuning the RTO timer toward the best performance of BP. A performance comparison between the optimal RTO timer proposed in this study and the existing commonly used RTO timers is also presented.
Autors: Ruhai Wang;Mingjian Qiu;Kanglian Zhao;Yi Qian;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Mar 2017, volume: 66, issue:3, pages: 2536 - 2550
Publisher: IEEE
 
» Optimal Scheduling for EV Charging Stations in Distribution Networks: A Convexified Model
Abstract:
A convexified model for EV charging station scheduling is proposed in this letter, which minimizes the total charging cost and the energy cost from the substation during the concerned time horizon. The model is transformed from the conventional model by using convex relaxation techniques, by which the globally optimal solution and high computational efficiency can be achieved. The proposed approach is validated by numerical simulations on a 15-bus distribution network.
Autors: Yue Song;Yu Zheng;David J. Hill;
Appeared in: IEEE Transactions on Power Systems
Publication date: Mar 2017, volume: 32, issue:2, pages: 1574 - 1575
Publisher: IEEE
 
» Optimal Sequences for Non-Orthogonal Multiple Access: A Sparsity Maximization Perspective
Abstract:
Non-orthogonal multiple access (NOMA) can improve the spectral efficiency of a multi-user system by enabling overload usage of radio resources. To eliminate the multiple access interference, the NOMA usually requires complicated signal processing, which may hinder its practical applications. One promising solution is to design sparse multiple access sequences for the NOMA, and then leverage the message passing algorithm to reduce the detection complexity. However, the optimal sequences for the NOMA that can achieve both the maximum sum rate and the maximum sparsity are still unknown. In this letter, the optimal sparsity of sum capacity-achievable NOMA sequences is theoretically given under the condition that the system load is not smaller than 2. To achieve the optimal sparsity, a construction method is further proposed by adopting the frame theory. The simulation results show that the constructed sequences have better sparsity compared with other sum capacity-achieving ones, and also higher sum rate compared with other sparse sequences.
Autors: Ting Qi;Wei Feng;Youzheng Wang;
Appeared in: IEEE Communications Letters
Publication date: Mar 2017, volume: 21, issue:3, pages: 636 - 639
Publisher: IEEE
 
» Optimal Spectrum Handoff Control for CRN Based on Hybrid Priority Queuing and Multi-Teacher Apprentice Learning
Abstract:
An optimal spectrum handoff scheme for cognitive radio networks (CRNs) is presented in this paper. This scheme has two novel features: 1) Hybrid rule-based priority queuing model: To overcome the limitations of preemptive resume priority and nonpreemptive resume priority (PRP/NPRP) queuing models, a hybrid queuing model with discretion rule is proposed to characterize the spectrum access priority among secondary users (SUs). This hybrid queuing model is then used to calculate the channel waiting time during spectrum handoff; and 2) Multiteacher apprentice learning: Unlike existing CRN cognition engine designs that focus on spectrum adaptation through SU self-learning (i.e., an SU learns how to adapt to the dynamic CRN environment by itself), we propose the concept of multiteacher knowledge transfer, wherein the multiple SUs that already have mature spectrum adaptation strategies share their knowledge with an inexperienced SU. Our simulation results show that the proposed new designs improve the spectrum handoff accuracy for the complex CRN environments.
Autors: Yeqing Wu;Fei Hu;Yingying Zhu;Sunil Kumar;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Mar 2017, volume: 66, issue:3, pages: 2630 - 2642
Publisher: IEEE
 
» Optimal Step-Skew Methods for Cogging Torque Reduction Accounting for Three-Dimensional Effect of Interior Permanent Magnet Machines
Abstract:
This paper proposes optimal step-skew methods for cogging torque reduction in interior permanent magnet (IPM) machines. First, a vector diagram method is employed to analyze the principle of a conventional three-step-skewed rotor, followed by two-dimensional (2-D) finite element (FE) validation. However, a considerable component of the cogging torque still exists according to 3-D FE analysis. End leakage flux and interaction between adjacent rotor steps are then investigated. To further reduce the residual cogging torque component, two improved step-skew methods are proposed—first, a rotor with optimal step-skew angles and, second, a rotor with optimal step lengths. Furthermore, the influence of manufacturing tolerance with axial placement of the rotor steps is investigated and leads to further corrections of the proposed methods, followed by analyses on other IPM machines having different stator slot/rotor pole combinations. Finally, prototypes are fabricated and tested to verify the foregoing analyses.
Autors: Xiao Ge;Z. Q. Zhu;Graham Kemp;David Moule;Connel Williams;
Appeared in: IEEE Transactions on Energy Conversion
Publication date: Mar 2017, volume: 32, issue:1, pages: 222 - 232
Publisher: IEEE
 
» Optimization of Duplication-Based Schedules on Network-on-Chip Based Multi-Processor System-on-Chips
Abstract:
Many applications such as streaming applications are both computation and communication intensive. The Multi-Processor System-on-Chip (MPSoC) based on Network-on-Chip (NoC) outperforms the multiprocessors with bus-based networking architecture in communication bandwidth and scalability, making it a better choice for implementing systems running these applications. It's important to schedule both the computation and communication onto processors and the networking architecture so as to satisfy the stringent timing requirements. To reduce or avoid inter-processor communication, task duplication has been employed in scheduling. Most of the available techniques for the duplication-based scheduling problem use heuristics to solve the problem, and seldom has any work studied further improving the schedule performance, despite the fact that the heuristic cannot provide quality guarantee. To fill in this gap, this paper introduces a duplication and mapping constrained task-communication co-scheduling problem that assumes the duplication strategy and task-to-processor mapping are known a priory, and proposes two Integer Linear Programming (ILP) formulations, i.e., CF-ILP and CA-ILP, to solve two editions of this problem, i.e., the contention-free problem and the contention-aware problem. The proposed ILP formulations optimize the ordering and timing of the communication and computation, thus improving the performance. Both synthesized and real applications are tested on a set of platforms to evaluate the performance of the proposed methods. The experimental results demonstrate the effectiveness of the proposed methods.
Autors: Qi Tang;Shang-Feng Wu;Jun-Wu Shi;Ji-Bo Wei;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Mar 2017, volume: 28, issue:3, pages: 826 - 837
Publisher: IEEE
 
» Optimized Design of Differential Moderate-Band BPF on Coupled Slotline Resonators
Abstract:
This letter presents an optimized design of differential moderate-band bandpass filter (BPF) with intrinsic common-mode rejection on three half-wavelength slotline resonators. The slotline resonator element’s unloaded -factor is highly enhanced by using a long coupling length. Thus, it can be utilized to construct a low insertion loss differential moderate-band BPF.
Autors: Xin Guo;Lei Zhu;Wen Wu;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Mar 2017, volume: 27, issue:3, pages: 263 - 265
Publisher: IEEE
 
» Optimized Identity-Based Encryption from Bilinear Pairing for Lightweight Devices
Abstract:
Lightweight devices such as smart cards and RFID tags have a very limited hardware resource, which could be too weak to cope with asymmetric-key cryptography. It would be desirable if the cryptographic algorithm could be optimized in order to better use hardware resources. In this paper, we demonstrate how identity-based encryption algorithms from bilinear pairing can be optimized so that hardware resources can be saved. We notice that the identity-based encryption algorithms from bilinear pairing in the literature must perform both elliptic curve group operations and multiplicative group operations, which consume a lot of hardware resources. We manage to eliminate the need of multiplicative group operations for encryption. This is a significant discovery since the hardware structure can be simplified for implementing pairing-based cryptography. Our experimental results show that our encryption algorithm saves up to 47 percent memory (27,239 RAM bits) in FPGA implementation.
Autors: Fuchun Guo;Yi Mu;Willy Susilo;Homer Hsing;Duncan S. Wong;Vijay Varadharajan;
Appeared in: IEEE Transactions on Dependable and Secure Computing
Publication date: Mar 2017, volume: 14, issue:2, pages: 211 - 220
Publisher: IEEE
 
» Optimized Settings of Droop Parameters Using Stochastic Load Modeling for Effective DC Microgrids Operation
Abstract:
Droop control is a widely used technique for load sharing in dc microgrids (MGs). However, it has an inherent limitation that leads to voltage deviations at the dc bus. More importantly, its current-sharing performance is degraded due to voltage drops across transmission line impedances. Depending on the amount of these voltage drops over the dc bus, droop control leads to different current-sharing errors and dc bus voltage degradations. Therefore, MG topology and loading conditions (LCs) have a considerable effect on current-sharing accuracy and voltage regulation. In this paper, an optimization procedure accounting all necessary information is introduced to find optimal droop parameters for the droop mechanism. First, a proper optimization problem is defined with required constraints and a cost function formulated as a summation of the current-sharing errors and the voltage degradations occurring at various LCs. Then, an optimization tool named as particle swarm is implemented to converge a satisfactory solution. During the computations, the cost impact of the current-sharing error at each LC is weighted based on the probability of occurrence of that LC, which is obtained from the stochastic load model for the considered MG. The effectiveness of the optimal droop parameters is verified through a simulation performed on MATLAB/Simulink and a dc MG test bench is prototyped for experimental validation.
Autors: Fatih Cingoz;Ali Elrayyah;Yilmaz Sozer;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Mar 2017, volume: 53, issue:2, pages: 1358 - 1371
Publisher: IEEE
 
» Optimizing Differentiated Latency in Multi-Tenant, Erasure-Coded Storage
Abstract:
Erasure codes are widely used in distributed storage systems since they provide space-optimal data redundancy to protect against data loss. Despite recent progress on quantifying average service latency when erasure codes are employed, there is very little work on providing differentiated latency among multiple tenants that may have different latency requirements. This paper proposes a novel framework for providing and optimizing differentiated latency in erasure-coded storage by investigating two policies, weighted queue and priority queue, for scheduling tenant requests. For both policies, we quantify service latency for different tenant classes for homogeneous files with arbitrary placement and service time distributions. We develop an optimization framework that jointly minimizes differentiated latency over three decision spaces: 1) data placement; 2) request scheduling; and 3) resource management. Efficient algorithms harnessing bipartite matching and convex optimization techniques are developed to solve the proposed optimization. Our solution enables elastic service-level agreements to meet heterogeneous application requirements. We further prototype our solution with both queuing models applied in an open-source, cloud storage deployment that simulates three geographically distributed data centers through bandwidth reservations. Experimental results validate our theoretical delay analysis and show significant joint latency reduction for different classes of files, providing valuable insights into service differentiation and elastic quality of service in erasure-coded storage systems.
Autors: Yu Xiang;Tian Lan;Vaneet Aggarwal;Yih-Farn Chen;
Appeared in: IEEE Transactions on Network and Service Management
Publication date: Mar 2017, volume: 14, issue:1, pages: 204 - 216
Publisher: IEEE
 
» Optimizing Green Energy, Cost, and Availability in Distributed Data Centers
Abstract:
Integrating renewable energy and ensuring high availability are two major requirements for geo-distributed data centers. Availability is ensured by provisioning spare capacity across the data centers to mask data center failures (either partial or complete). We propose a mixed integer linear programming formulation for capacity planning while minimizing the total cost of ownership (TCO) for highly available, green, distributed data centers. We minimize the cost due to power consumption and server deployment while targeting a minimum usage of green energy. Solving our model shows that capacity provisioning considering green energy integration not only lowers carbon footprint but also reduces the TCO. Results show that up to 40% green energy usage is feasible with a marginal increase in the TCO compared with the other cost-aware models.
Autors: Rakesh Tripathi;S. Vignesh;Venkatesh Tamarapalli;
Appeared in: IEEE Communications Letters
Publication date: Mar 2017, volume: 21, issue:3, pages: 500 - 503
Publisher: IEEE
 
» ORBIT: A Platform for Smartphone-Based Data-Intensive Sensing Applications
Abstract:
Owing to the rich processing, multi-modal sensing, and versatile networking capabilities, smartphones are increasingly used to build data-intensive embedded sensing applications. However, various challenges must be systematically addressed before smartphones can be used as a generic embedded sensing platform, including high power consumption, lack of real-time functionality, and user-friendly embedded programming support. This paper presents ORBIT, a smartphone-based platform for data-intensive embedded sensing applications. ORBIT features a tiered architecture, in which a smartphone can interface to an energy-efficient peripheral board and/or a cloud service. ORBIT as a platform addresses the shortcomings of current smartphones while utilizing their strengths. ORBIT provides a profile-based task partitioning that allows it to intelligently dispatch the processing tasks among the tiers to minimize the system power consumption. ORBIT also provides a data processing library that includes two mechanisms namely adaptive delay-quality trade-off and data partitioning via multi-threading to optimize resource usage. Moreover, ORBIT supplies an annotation-based programming API for developers that significantly simplifies the application development and provides programming flexibility. Extensive microbenchmark evaluation and three case studies including seismic sensing, visual tracking using an ORBIT robot, and multi-camera 3D reconstruction, validate the generic design of ORBIT.
Autors: Mohammad-Mahdi Moazzami;Dennis E. Phillips;Rui Tan;Guoliang Xing;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: Mar 2017, volume: 16, issue:3, pages: 801 - 815
Publisher: IEEE
 
» Orbital mechanics
Abstract:
Let's say you are the program manager of a very large, complex system. Perhaps it's an aircraft, or a building, or a communications network. Your system is valued at over US $500 million. Could you imagine being told that you won't ever be able to maintain it? That, once it's operational, it will never be inspected, repaired, or upgraded with new hardware? . Welcome to the world of satellite building. After a satellite is launched, it is on a one-way journey to disrepair and obsolescence, and there is little anyone can do to alter that path. Faults (which are called anomalies in the space business) can only be diagnosed remotely, using data and inferential reasoning. Software fixes and upgrades may be possible, but most mechanical anomalies can't be corrected. And hardware can't be replaced, which means that even if a satellite is operating well, it could lose its state-of-the-art status just a few years into a typical 15-year lifetime.
Autors: Gordon Roesler;Paul Jaffe;Glen Henshaw;
Appeared in: IEEE Spectrum
Publication date: Mar 2017, volume: 54, issue:3, pages: 44 - 50
Publisher: IEEE
 
» Out-of-Step Protection Based on Equal Area Criterion
Abstract:
This paper proposes a novel self-tuning and response-based method for estimation of a single generator instability after large disturbances in multimachine power systems. The proposed method takes advantage of the equal-area criterion and least-squares method. The instability is determined by monitoring the cumulative acceleration and deceleration areas in the power–angle plane. These areas are continuously computed in order to determine whether or not the rotor angle reaches the unstable equilibrium point (UEP). A real-time curve-fitting algorithm based on the least-squares method is suggested to estimate the UEP. The generator rotor angle is calculated readily using three-phase voltages and currents taken at the generator terminal, and no further information such as fault clearing instant is required. The algorithm is independent upon changes in network parameters and only needs locally measured quantities. Self-tuning and response-based operation are the main advantages of the proposed algorithm over the other existing algorithms. The performance of the proposed algorithm and its independence from the network configuration are successfully validated and compared with that of impedance-based out-of-step protection relays.
Autors: Bahman Alinezhad;Hossein Kazemi Karegar;
Appeared in: IEEE Transactions on Power Systems
Publication date: Mar 2017, volume: 32, issue:2, pages: 968 - 977
Publisher: IEEE
 
» Outage Probability Analysis and Power Splitter Designs for SWIPT Relaying Systems With Direct Link
Abstract:
This letter investigates the outage performance for simultaneous wireless information and power transfer (SWIPT) relaying systems in the presence of direct link between the source and the destination. For the SWIPT, we employ a power splitter (PS) at the relay, which splits the received signal into the information transmission and the energy harvesting parts. First, we provide an analysis of the outage probability as a closed-form based on a high signal-to-noise ratio approximation. From the analysis, it is recognized that the diversity order of the SWIPT relaying systems equals that of the non-SWIPT cases. The closed-form outage expression also enables us to obtain a simple expression for the PS factor which minimizes the outage probability. Simulation results demonstrate the accuracy of the derived analysis and the efficiency of the proposed PS scheme.
Autors: Hoon Lee;Changick Song;Soo-Hwan Choi;Inkyu Lee;
Appeared in: IEEE Communications Letters
Publication date: Mar 2017, volume: 21, issue:3, pages: 648 - 651
Publisher: IEEE
 
» Overcoming IoT Language Barriers Using Smartphone SDRs
Abstract:
In the Internet of Things (IoT) era, smartphones are expected to frequently interact with IoT devices and even facilitate various IoT applications. Due to limited roles, energy constraints, etc., however, IoT devices may use mission-tailored or proprietary wireless protocols that smartphones do not speak natively. In this paper, we propose a novel approach to the wireless “language barrier” problem between the smartphones and IoT devices of the future. We first demonstrate that smartphones have become powerful enough to process software defined radio (SDR) for some known wireless protocols. Moreover, we show that the SDRs can be packaged as “apps” and be downloaded from app stores for OS-independent deployment. Second, we show different SDR protocols on the smartphone can concurrently run through a shared RF to serve multi-tasked applications on it as might happen in diversified IoT environments. For proof-of-concept, we implement a prototype architecture that has all the SDR logic and supporting middleware on an Android smartphone which uses a USRP as the simple RF-end. Finally, we demonstrate that IEEE 802.11p and IEEE 802.15.4 SDRs on a smartphone, respectively, communicate with a ZigBee sensor mote, a ZigBee smart lightbulb, and a commercial Wireless Access in Vehicular Environment (WAVE) device, concurrently.
Autors: Yongtae Park;Seungho Kuk;Inhye Kang;Hyogon Kim;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: Mar 2017, volume: 16, issue:3, pages: 816 - 828
Publisher: IEEE
 
» Oxidation Resistive, CMOS Compatible Copper-Based Alloy Ultrathin Films as a Superior Passivation Mechanism for Achieving 150 °C Cu–Cu Wafer on Wafer Thermocompression Bonding
Abstract:
Surface passivation plays a dual role of protecting copper (Cu) from getting oxidized and reducing the surface roughness of Cu thin film and thus enables low-temperature Cu–Cu bonding. In this paper, we utilized an oxidation resistive, CMOS compatible copper–nickel-based alloy, constantan as a passivation layer, as it does not get oxidized at room temperature and is also CMOS damascene process compatible. Systematically optimized ultrathin, constantan (2 nm) on Cu surface not only protected Cu from oxidation but also reduced the surface roughness to about 0.7 nm, which led to Cu–Cu bonding at a temperature as low as 150 °C at bar pressure. Cross-sectional TEM of bonded Cu layer reveals very significant interdiffusion and grain growth between the Cu films resulting in a zigzag bonding interface and the presence of Cu grains that extend across the entire bonding layer. Furthermore, reliability investigation of passivated Cu bonded structure was demonstrated using current stressing, temperature cycling test, and relative humidity test, which suggest excellent stable bonding without electrical performance degradation. This method of alloy-based passivation is confirmed to be effective and enable low temperature, low-pressure Cu–Cu wafer on wafer bonding for 3-D integration applications.
Autors: Asisa Kumar Panigrahi;Tamal Ghosh;Siva Rama Krishna Vanjari;Shiv Govind Singh;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Mar 2017, volume: 64, issue:3, pages: 1239 - 1245
Publisher: IEEE
 
» Packaged Microstrip Line: A New Quasi-TEM Line for Microwave and Millimeter-Wave Applications
Abstract:
In this paper, a new quasi-transverse electromagnetic (TEM) microstrip line, named as packaged microstrip line, is proposed for microwave and millimeter-wave applications. It is comprised of three dielectric substrates: a base layer to place the metal strip, a top layer to build the perfect magnetic conductor (PMC) shielding with periodic plated vias, and a middle layer to separate the PMC layer from the metal strip and the bottom ground plane. With the top PMC shielding, this novel microstrip line no longer suffers from issues of radiation losses, surface waves, or cavity resonances that exist in the classical microstrip line without or with a metallic shielding box. Also, the unwanted higher order mode created in the stripline by any vertical asymmetry between the ground planes will not be generated in the packaged microstrip line. In addition, the fundamental quasi-TEM mode will help this novel line avoid the mode conversion losses when integrated with other quasi-TEM lines, which happen to the substrate-integrated waveguide due to its fundamental TE10 mode. This paper focuses on the effects of the PMC-layer substrate on this line performance. We present how to adopt a proper substrate for each layer of the packaged microstrip line considering both stopband and transmission loss, and how to design the linewidth for a given characteristic impedance. Two different transition schemes of the packaged microstrip line to the standard microstrip line are taken into account. Two prototypes of the proposed packaged microstrip lines using different substrates for the PMC layer are fabricated. The measured and simulated results show good agreement.
Autors: Jing Zhang;Xiupu Zhang;Dongya Shen;Ahmed A. Kishk;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Mar 2017, volume: 65, issue:3, pages: 707 - 719
Publisher: IEEE
 
» Packet Size Optimization in Wireless Sensor Networks for Smart Grid Applications
Abstract:
Wireless sensor networks (WSNs) are envisioned to be an important enabling technology for smart grid (SG) due to the low cost, ease of deployment, and versatility of WSNs. Limited battery energy is the tightest resource constraint on WSNs. Transmission power control and data packet size optimization are powerful mechanisms for prolonging network lifetime and improving energy efficiency. Increasing transmission power will reduce the bit error rate (BER) on some links, however, utilizing the highest power level will lead to inefficient use of battery energy because on links with low path loss achieving low BER is possible without the need to use the highest power level. Utilizing a large packet size is beneficial for increasing the payload-to-overhead ratio, yet, lower packet sizes have the advantage of lower packet error rate. Furthermore, transmission power level assignment and packet size selection are interrelated. Therefore, joint optimization of transmission power level and packet size is of utmost importance in WSN lifetime maximization. In this study, we construct a detailed link layer model by employing the characteristics of Tmote Sky WSN nodes and channel characteristics based on actual measurements of SG path loss for various environments. A novel mixed integer programming framework is created by using the aforementioned link layer model for WSN lifetime maximization by joint optimization of transmission power level and data packet size. We analyzed the WSN performance by systematic exploration of the parameter space for various SG environments through the numerical solutions of the optimization model.
Autors: Sinan Kurt;Huseyin Ugur Yildiz;Melike Yigit;Bulent Tavli;Vehbi Cagri Gungor;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Mar 2017, volume: 64, issue:3, pages: 2392 - 2401
Publisher: IEEE
 
» Parallel and Distributed Resource Allocation With Minimum Traffic Disruption for Network Virtualization
Abstract:
Wireless network virtualization has been advocated as one of the most promising technologies to provide multifarious services and applications for the future Internet by enabling multiple isolated virtual wireless networks to coexist and share the same physical wireless resources. Based on the multiple concurrent virtual wireless networks running on the shared physical substrate, service providers can independently manage and deploy different end-users services. This paper proposes a new formulation for bandwidth allocation and routing problem for multiple virtual wireless networks that operate on top of a single substrate network to minimize the operation cost of the substrate network. We also propose a preventive traffic disruption model for virtual wireless networks to minimize the amount of traffic that service providers have to reduce when substrate links fail by incorporating -norm into the objective function. Due to the large number of constraints in both normal state and link failure states, the formulated problem becomes a large-scale optimization problem and is very challenging to solve using the centralized computational method. Therefore, we propose the decomposition algorithms using the alternating direction method of multipliers that can be implemented in a parallel and distributed fashion. The simulation results demonstrate the computational efficiency of our proposed algorithms as well as the advantage of the formulated model in ensuring the minimal amount of traffic disruption when substrate links fail.
Autors: Hung Khanh Nguyen;Yanru Zhang;Zheng Chang;Zhu Han;
Appeared in: IEEE Transactions on Communications
Publication date: Mar 2017, volume: 65, issue:3, pages: 1162 - 1175
Publisher: IEEE
 
» Parallel Augmented Lagrangian Relaxation for Dynamic Economic Dispatch Using Diagonal Quadratic Approximation Method
Abstract:
Dynamic economic dispatch (DED) over multiple time periods is a large-scale coupled spatial-temporal optimization problem. Therefore, the Lagrangian relaxation method has been widely used to split the large-scale optimization problem with coupled structure into several small sub-problems. In order to bring robustness for updating the dual multipliers and yielding convergence without strong assumptions, the augmented Lagrangian relaxation method is introduced in this paper. However, the added penalty term in an augmented Lagrangian function is non-separable, which leads to the difficulty in achieving full decomposition for parallel computation. To address this problem, a diagonal quadratic approximation method is employed to yield an approximated block separation of the non-separable penalty term. Furthermore, the ramp rate constraints are relaxed in this paper, so that the DED model is decomposed into several single-period economic dispatch models that can be efficiently handled in parallel, called the parallel augmented Lagrangian relaxation method. Particularly, the proposed relaxation strategy has a high separability feature which theoretically leads to sound convergence property. Numerical results on the IEEE 118-bus and a practical Polish 2383-bus test system over a different number of time periods show the effectiveness of the proposed method. In addition, the proposed method can be extended to other coupled spatial-temporal scheduling problems in power systems, such as energy storage dispatch.
Autors: Tao Ding;Zhaohong Bie;
Appeared in: IEEE Transactions on Power Systems
Publication date: Mar 2017, volume: 32, issue:2, pages: 1115 - 1126
Publisher: IEEE
 
» Parameters and Methods for ADCs Testing Compliant With the Guide to the Expression of Uncertainty in Measurements
Abstract:
Virtual instruments let the user define custom measurement approaches to cope with specific goals. The use of virtual instruments also raises an important issue, which concerns the evaluation of the uncertainty of the measurement results. To face this issue, a change in the praxis currently adopted to interpret the analog-to-digital converter (ADC) datasheets released by the manufacturers for documenting their products seems necessary. This change should be the consequence of modifications and/or integrations of the standard documents adopted by the same manufactures, by the way proposed by the scientific community. Modifications and/or integrations should assure the compliance between parameters and methods for ADC testing and recommendations contained in the guide to the expression of uncertainty in measurement.
Autors: Aldo Baccigalupi;Mauro D’Arco;Annalisa Liccardo;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Mar 2017, volume: 66, issue:3, pages: 424 - 431
Publisher: IEEE
 
» Parametric Simulation on Reduction of $S$ -Band Rear Bistatic Radar Cross Section of Jet Engine With Vector Thrust Nozzle via Plasmatized Exhaust
Abstract:
The feasibility of using plasmatized exhaust to reduce engine rear bistatic radar cross section (RCS) is studied. The possible range of plasma density inside a jet engine when alkaline additives are used in fuel is analyzed via the Saha equation, and the results show that there should be high density plasma. Next, the S-band rear bistatic RCS of a jet engine with or without the vector thrust nozzle is simulated using a finite-difference time-domain code. Then, the RCS when exhaust is plasmatized is simulated to make comparison. The results show that even with low density plasma, the effective shape of the vector thrust nozzle is changed, and the RCS is reduced. As the plasma density becomes higher, the reflection becomes stronger and the radar wave penetration into the plasmatized exhaust becomes less. The change in RCS is strongly related to the direction and shape of the jet exhaust, besides the plasma density.
Autors: Shen Shou Max Chung;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Mar 2017, volume: 45, issue:3, pages: 388 - 404
Publisher: IEEE
 
» Parametric Synthesis of Well-Scanning Isophoric Pencil Beams
Abstract:
Interest in uniformly illuminated (isophoric) density-tapered planar antenna arrays has recently revived. For arrays consisting of concentric rings of elements, we present a nonstochastic algorithm that calculates ring radii for generation of pencil beams without the need for prior specification of the number of rings. Use of the algorithm is illustrated by application to multibeam coverage of the Earth. The use of its results as the starting point of a stochastic optimization has led to complete solution of a hitherto recalcitrant synthesis problem.
Autors: A. A. Salas-Sánchez;J. Fondevila-Gómez;J. A. Rodríguez-González;F. J. Ares-Pena;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Mar 2017, volume: 65, issue:3, pages: 1422 - 1427
Publisher: IEEE
 
» Partial Randomness Hashing for Large-Scale Remote Sensing Image Retrieval
Abstract:
With the rapid progress of satellite and aerial vehicle technologies, large-scale remote sensing (RS) image retrieval has recently become an important research issue in geosciences. Hashing-based searching approaches have been widely employed in content-based image retrieval tasks. However, most hash schemes compromise between learning efficiency and retrieval accuracy, and can thus barely satisfy the precise requirements in RS data analysis. To address these shortcomings, we introduce a partial randomness scheme for learning hash functions, which is referred to as partial randomness hashing (PRH). Specifically, for constructing hash functions, a part of model parameter values are randomly generated and the remaining ones are trained based on RS images. The randomness enables an efficient hash function construction and the trained model parameters encode characteristics from RS images. The coplay between random and trained model parameters results in both efficient and effective learning scheme for constructing hash functions. Experiments on two large public RS image data sets have shown that our PRH method outperforms state of the arts in terms of both learning efficiency and retrieval accuracy.
Autors: Peng Li;Peng Ren;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Mar 2017, volume: 14, issue:3, pages: 464 - 468
Publisher: IEEE
 
» Partial Stabilization of Input-Output Contact Systems on a Legendre Submanifold
Abstract:
This technical note addresses the structure preserving stabilization by output feedback of conservative input-output contact systems, a class of input-output Hamiltonian systems defined on contact manifolds. In the first instance, achievable contact forms in closed-loop and the associated Legendre submanifolds are analysed. In the second instance the stability properties of a hyperbolic equilibrium point of a strict contact vector field are analysed and it is shown that the stable and unstable manifolds are Legendre submanifolds. In the third instance the consequences for the design of stable structure preserving output feedback are derived: in closed-loop one may achieve stability only relatively to some invariant Legendre submanifold of the closed-loop contact form and furthermore this Legendre submanifold may be used as a control design parameter. The results are illustrated along the technical note on the example of heat transfer between two compartments and a controlled thermostat.
Autors: Hector Ramirez;Bernhard Maschke;Daniel Sbarbaro;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Mar 2017, volume: 62, issue:3, pages: 1431 - 1437
Publisher: IEEE
 
» Partition Search Revisited
Abstract:
Partition search is a form of game search, proposed by Matthew L. Ginsberg in 1996, who wrote that the method “incorporates dependency analysis, allowing substantial reductions in the portion of the tree that needs to be expanded.” In this paper, some improvements of the partition search algorithm are proposed. The effectiveness of the most important extension we contribute, which we call local partition search, has been verified experimentally. The results obtained (which we present in the paper) show that using this extension, leads, in the case of bridge, to a significant reduction (almost by half) of the search tree size and calculation time. Another extension we proposed allows for more effective usage of the transposition table (using it to narrow the search window or by cutting more than one entry). Additionally, we contribute a formal proof of the correctness of all presented partition search variants. We draw conclusions from it about a possible generalization of partition search by making the definition of a partition system less restrictive. We also provide a formal definition of a partition system for the double dummy bridge.
Autors: Piotr Beling;
Appeared in: IEEE Transactions on Computational Intelligence and AI in Games
Publication date: Mar 2017, volume: 9, issue:1, pages: 76 - 87
Publisher: IEEE
 
» Passive Realization of Fractional-Order Impedances by a Fractional Element and RLC Components: Conditions and Procedure
Abstract:
In this paper, conditions for checking the realizability of fractional-order impedance functions by passive networks composed of a fractional element (either a fractional capacitor or a fractional inductor) and some RLC components are derived. To this end, at first the newly obtained conditions for realizability of fractional-order impedance functions by a passive network composed of a fractional capacitor and some RLC components are extended to include the case that the polynomials involving in the impedance function can have roots on the imaginary axis. Then, the necessary and sufficient conditions are found on a fractional-order impedance function to be realized by a passive network composed of a fractional element and some RLC components. Furthermore, a procedure for finding the realization in the realizable cases is proposed. Finally, the realizability conditions for a special class of fractional-order impedance functions are simplified.
Autors: Mohammad Saeed Sarafraz;Mohammad Saleh Tavazoei;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Mar 2017, volume: 64, issue:3, pages: 585 - 595
Publisher: IEEE
 
» Path-Diversity-Aware Fault-Tolerant Routing Algorithm for Network-on-Chip Systems
Abstract:
Network-on-Chip (NoC) is the regular and scalable design architecture for chip multiprocessor (CMP) systems. With the increasing number of cores and the scaling of network in deep submicron (DSM) technology, the NoC systems become subject to manufacturing defects and have low production yield. Due to the fault issues, the reduction in the number of available routing paths for packet delivery may cause severe traffic congestion and even to a system crash. Therefore, the fault-tolerant routing algorithm is desired to maintain the correctness of system functionality. To overcome fault problems, conventional fault-tolerant routing algorithms employ fault information and buffer occupancy information of the local regions. However, the information only provides a limited view of traffic in the network, which still results in heavy traffic congestion. To achieve fault-resilient packet delivery and traffic balancing, this work proposes a Path-Diversity-Aware Fault-Tolerant Routing (PDA-FTR) algorithm, which simultaneously considers path diversity information and buffer information. Compared with other fault-tolerant routing algorithms, the proposed work can improve average saturation throughput by 175 percent with only 8.9 percent average area overhead and 7.1 percent average power overhead.
Autors: Yu-Yin Chen;En-Jui Chang;Hsien-Kai Hsin;Kun-Chih (Jimmy) Chen;An-Yeu (Andy) Wu;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Mar 2017, volume: 28, issue:3, pages: 838 - 849
Publisher: IEEE
 

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