Electrical and Electronics Engineering publications abstract of: 07-2016 sorted by title, page: 0

» “Friend is Treasure”: Exploring and Exploiting Mobile Social Contacts for Efficient Task Offloading
Abstract:
In this paper, we investigate the task offloading issue in mobile social networks. Although the “d-choice” paradigm in “ball and bin” theory had shown the power of random choice in load balancing with a random walk model, its performance could be fairly poor where real-trace data sets are concerned. According to our preliminary evaluation results with “MobiClique,” the “d-choice” scheme could not achieve well-balanced allocations in a real-trace data set. Nevertheless, it would bring fundamental challenges to task reassignment in the following aspects: First of all, some of the friendships are relatively stable, which would lead to a more imbalanced task assignment, even if the “d-choice” scheme is applied for balancing. Second, some users would meet quite infrequently, which could inevitably lead to intolerable time delay and unfair task allocations. In tackling these difficulties, we revisit the real data sets for exploring the contact property among users. We find that the frequently met users could be leveraged for efficient task execution due to higher task priority. To this end, we propose the “ Top-K” algorithm, leveraging the basic concept, i.e., “your friends are more powerful than you,” which encourages mobile users to assign tasks among intimate friends instead of pure random assignment. With careful selections of “Top-K” friends, we achieve balanced load and guaranteed performance at the same time. Experimental studies verify our scheme and show the effectiveness with three typical data trace sets, including “MobiClique.” In this typical networking scenario, ours outperforms the conventional random choice scheme up to 15 and the social relationship assignment without priority- method up to 9 . Moreover, the “Top-K” scheme could be adaptive, even when no intimate friends are available. By scaling the “K” factor to larger values, our scheme outperforms random assignment and could be inspiringly close to the optimal solution. In summary, ours could effectively explore the social relationship and leverage it for efficient task assignment, which would further encourage more mobile users to work together under the rule of social contacts.
Autors: Li, Q.;Yang, P.;Yan, Y.;Li, X.;Xiong, Y.;Wang, B.;Sun, X.;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jul 2016, volume: 65, issue:7, pages: 5485 - 5496
Publisher: IEEE
 
» 10-Gb/s Distributed Amplifier-Based VCSEL Driver IC With ESD Protection in 130-nm CMOS
Abstract:
This paper presents a low-power 10-Gb/s vertical cavity surface emitting laser (VCSEL) driver integrated circuit (IC) with electrostatic discharge (ESD) protection in the 130-nm CMOS technology. A distributed amplifier (DA)-based modulator is proposed to boost the driver bandwidth. It employs artificial transmission lines to cancel the device parasitic capacitances of the driver. A distributed ESD protection technique is applied to equalize the group delay of the DA to optimize the jitter performance. To minimize the silicon area, the optimal number of DA taps in the proposed modulator has been derived. To compensate for the capacitive load and the channel losses at the output of the driver, a frequency-domain preemphasis scheme is proposed. The proposed DA modulator occupies an area of 0.69 mm2, and the entire driver IC has a die size of mm, including the pads. Both electrical and optical tests have been carried out to characterize the performance of the proposed VCSEL driver IC. Measurements at a data rate of 10-Gb/s demonstrate a typical power consumption of 85 mW under a single 2.5 V supply voltage (49 mW, if separate 1.2 and 2.5 V supplies are used) and an rms jitter of 0.63 and 1.12 ps for the electrical test and optical test, respectively.
Autors: Zhang, T.;Gui, P.;Chakraborty, S.;Liu, T.;Wu, G.;Moreira, P.;Tavernier, F.;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Jul 2016, volume: 24, issue:7, pages: 2502 - 2510
Publisher: IEEE
 
» 2-D Magnetic Domain Patterns on Thin Films With Perpendicular Magnetic Anisotropy
Abstract:
We theoretically argue on the connectivity of mazes that are expected to appear in magnetic thin films with magnetic perpendicular anisotropy. Following the finding of persistent magnetic structures and their direct relationship with the connectivity of the mazes existing as demagnetized states in our previous study (Iwano et al., J. Appl. Phys. vol. 117, 17A704, 2015), we extend our analyses based on the framework of a 2-D Ginzburg–Landau simulation augmented by the dipole–dipole interaction, to generate as many as 100 mazes under zero magnetic field. Next, we elevate the field and coarse-grain the structure while maintaining its fundamental topology. We judge the nature of the obtained persistent structures from averaged magnetization and finally find that more than 70% of mazes are connected for the present system size. This result suggests that these mazes exceed the so-called percolation threshold, namely, that all the mazes are connected in the limit of an infinite system.
Autors: Iwano, K.;Mitsumata, C.;Ono, K.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Jul 2016, volume: 52, issue:7, pages: 1 - 4
Publisher: IEEE
 
» 3D Reconstruction of Human Laryngeal Dynamics Based on Endoscopic High-Speed Recordings
Abstract:
Standard laryngoscopic imaging techniques provide only limited two-dimensional insights into the vocal fold vibrations not taking the vertical component into account. However, previous experiments have shown a significant vertical component in the vibration of the vocal folds. We present a 3D reconstruction of the entire superior vocal fold surface from 2D high-speed videoendoscopy via stereo triangulation. In a typical camera-laser set-up the structured laser light pattern is projected on the vocal folds and captured at 4000 fps. The measuring device is suitable for in vivo application since the external dimensions of the miniaturized set-up barely exceed the size of a standard rigid laryngoscope. We provide a conservative estimate on the resulting resolution based on the hardware components and point out the possibilities and limitations of the miniaturized camera-laser set-up. In addition to the 3D vocal fold surface, we extended previous approaches with a G2-continuous model of the vocal fold edge. The clinical applicability was successfully established by the reconstruction of visual data acquired from 2D in vivo high-speed recordings of a female and a male subject. We present extracted dynamic parameters like maximum amplitude and velocity in the vertical direction. The additional vertical component reveals deeper insights into the vibratory dynamics of the vocal folds by means of a non-invasive method. The successful miniaturization allows for in vivo application giving access to the most realistic model available and hence enables a comprehensive understanding of the human phonation process.
Autors: Semmler, M.;Kniesburges, S.;Birk, V.;Ziethe, A.;Patel, R.;Doellinger, M.;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Jul 2016, volume: 35, issue:7, pages: 1615 - 1624
Publisher: IEEE
 
» In Vitro Viscosity Measurement on Superparamagnetic Nanoparticle Suspensions
Abstract:
In this paper, we propose and demonstrate a Brownian relaxation-based mixing-frequency method to test sample viscosities. This method uses excitatory and detection coils and Brownian relaxation-dominated superparamagnetic nanoparticles, which are sensitive to the characteristics of the liquid environment such as viscosity. Oscillating magnetic fields can induce harmonics through the nonlinear magnetization curve of superparamagnetic nanoparticles. Phase lag of the third-harmonic signal and the induced voltage ratio of the fifth over the third harmonic signals are collected. We build up standard graphs by plotting collected data from eight magnetic nanoparticle (MNP) mixtures with different viscosities. For any unknown liquids mixed with MNPs, we can collect phase lag and voltage ratio information and insert these data into the aforementioned standard graphs. This in vitro viscosity test can be done in 1 min. Our experimental result showed a 0.3% error rate for the liquid viscosity test.
Autors: Wu, K.;Ye, C.;Liu, J.;Wang, Y.;Feng, Y.;Wang, J.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Jul 2016, volume: 52, issue:7, pages: 1 - 4
Publisher: IEEE
 
» A 1–16 Gb/s All-Digital Clock and Data Recovery With a Wideband High-Linearity Phase Interpolator
Abstract:
An all-digital phase interpolator (PI)-based clock and data recovery (CDR) is proposed in this paper to accommodate any data rate continuously from 1 to 16 Gb/s with quadrature sampling clocks from 4 to 8 GHz. A new low-power two-step PI (TSPI) with high linearity over 4–8 GHz range is presented. The all-digital CDR control loop adopts a multimode phase detection scheme enabling continuous data rate support. The digital architecture not only eliminates the large filtering capacitor but also makes the design more tolerant to process, voltage, and temperature variations. The CDR core occupies 0.088 mm2 in a commercial 65-nm CMOS technology and consumes 73.1 mA at 16 Gb/s from a 1.2 V power supply. The differential nonlinearity of the PI is measured to be within 0.48 LSB. The measurement results show that this CDR can function at the proposed phase detection modes and is able to exceed the synchronous optical networking (SONET) OC-192 jitter tolerance mask at least by 0.2 unit interval at high frequencies (4–100 MHz) with a pseudorandom binary sequence data pattern at 10 Gb/s and a target bit error rate of .
Autors: Wu, G.;Huang, D.;Li, J.;Gui, P.;Liu, T.;Guo, S.;Wang, R.;Fan, Y.;Chakraborty, S.;Morgan, M.;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Jul 2016, volume: 24, issue:7, pages: 2511 - 2520
Publisher: IEEE
 
» A 1-GS/s 9-bit Zero-Crossing-Based Pipeline ADC Using a Resistor as a Current Source
Abstract:
A zero-crossing-based circuit (ZCBC) is a promising technique for low-power high-resolution pipeline analog-to-digital converters (ADCs). Unfortunately, operating ZCBC ADCs at high speeds near 1 GS/s is quite challenging due to the delay of the zero-crossing detector that introduces nonlinear gain and offset errors. To solve nonlinearity, we propose a ZCBC pipeline ADC that employs a passive resistor as a current source. Due to its inherent linearity, the resistor-based ZCBC eliminates the input dependency of the interstage gain and offset errors, allowing a simple calibration. Furthermore, a background offset calibration scheme is proposed to cope with the large offset that results from high-speed operation. A prototype ADC implemented in 65-nm CMOS achieves an SNDR/SFDR of 47.26/62.64 dB at 1 GS/s while consuming 46.52 mW from 1 V supply.
Autors: Kim, Y.-H.;Cho, S.;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Jul 2016, volume: 24, issue:7, pages: 2570 - 2579
Publisher: IEEE
 
» A 151-nW Adaptive Delta-Sampling ADC for Ultra-Low Power Sensing Applications
Abstract:
This brief presents a novel analog-to-digital converter (ADC) with adaptive delta-sampling for ultra-low power sensing applications. By sampling only the incremental value of the input signal and adaptively adjusting the sampling frequency, the proposed ADC can achieve the same resolution and conversion range with less number of bits than the conventional ADC. Meanwhile, the power consumption is also very much reduced. The proposed 8-bit ADC is fabricated in a 0.18- CMOS technology. It achieves 7.3 effective number of bits at an adaptive sampling frequency of 20 kHz/2 kHz, consuming only 151 nW for a neural signal acquisition application.
Autors: Yang, Y.;Zhou, J.;Liu, X.;Cheong, J.;Goh, W.;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Jul 2016, volume: 63, issue:7, pages: 638 - 642
Publisher: IEEE
 
» A 2-Approximation Algorithm for Scheduling Parallel and Time-Sensitive Applications to Maximize Total Accrued Utility Value
Abstract:
For a time-sensitive application, the usefulness of its end results (also called the application's accrued utility value in the paper) depends on the time when the application is completed and its results are delivered. In this paper, we address the accrued utility value maximization problem for narrow parallel and time-sensitive applications. We first consider the problem in the context of a discrete time domain and present the Spatial-Temporal Interference Based (STIB) scheduling algorithm. We formally prove that the STIB algorithm is a 2-approximation algorithm. Second, we extend our work to a continuous time domain and present a heuristic scheduling algorithm, i.e., the Continuous Spatial-Temporal Interference Based (STIB-C) algorithm to maximize the system's total accrued utility value when the system operates in a continuous time domain. The extensive empirical evaluations reveal that: (1) in a discrete time domain, the systems’ total accrued utility values obtained through the STIB algorithm are consistent with the theoretic bound, i.e., they never go below 50 percent of the optimal value. In fact, on average, the STIB algorithm can achieve over 92.5 percent of the optimal value; (2) compared to other scheduling policies listed in the literature, the developed STIB and STIB-C algorithms have clear advantages in terms of the system's total accrued utility value and the profitable application ratio. In particular, in terms of the system's total accrued utility value, both the STIB  and the STIB-C  algorithms achieve as much as six times for both the First Come First Come Serve(FCFS) with backfilling algorithm and the Gang Earliest Deadline First (EDF) algorithm, and 4.5 times for the 0-1 Knapsack based scheduling algorithm. In terms of the profitable application ratio, both the STIB and the STIB-C  algorithms obtain as much as four times for both the FCFS with bac- filling algorithm and the Gang EDF algorithm, and two times for the 0-1 Knapsack based scheduling algorithm.
Autors: Li, S.;Song, M.;Wan, P.;Ren, S.;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Jul 2016, volume: 27, issue:7, pages: 1864 - 1878
Publisher: IEEE
 
» A 32 000 r/min Axial Flux Permanent Magnet Machine for Energy Storage With Mechanical Stress Analysis
Abstract:
This paper focuses on the design and analysis of a high-speed axial flux permanent magnet (PM) machine for an aerospace flywheel energy storage system. The design target is to experimentally verify the sinusoidal back electromotive force (EMF) considering the mechanical stress limitation of the machine at a speed of 32 000 r/min. Two machine models based on ferrite and SmCo PMs have been proposed. First, the back EMF analysis using a 3-D finite-element method is performed to determine the performance of the two models. Second, the mechanical stress analysis is performed to check the durability of the rotor strength. Finally, the selected model utilizing the ferrite PMs has been manufactured and tested at 32 000 r/min to validate its effectiveness at high-speed operation.
Autors: Kumar, S.;Lipo, T.A.;Kwon, B.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Jul 2016, volume: 52, issue:7, pages: 1 - 4
Publisher: IEEE
 
» A 54- Inverter-Based Low-Noise Single-Ended to Differential VGA for Second Harmonic Ultrasound Probes in 65-nm CMOS
Abstract:
This brief presents an inverter-based low-noise single-ended to differential continuous-time variable gain amplifier (VGA) for 2–6-MHz second harmonic cardiac ultrasound imaging probes. The proposed VGA is based on a transimpedance amplifier and composed of resistive arrays and three equal inverters to form the resistive feedback loop. The inverters operate in the class C mode by being biased in the subthreshold region to improve both the power and noise performances of the VGA. The 6-bit thermometer resistive arrays can control the gain range from −1 to 21 dB for a 2-D piezoelectric transducer (PZT) model, and for a 50- source resistor, the gain range is from 20 to 26 dB. The second harmonic distortion (HD2) is lower than −55 dB in most cases due to the single-ended to differential conversion, and the equivalent input referred noise is 7 at 5 MHz with the maximum gain. The VGA is fabricated in 65-nm CMOS technology and has the power consumption of 54 at a supply voltage of 0.5 V. The die size of the VGA is .
Autors: Wang, P.;Ytterdal, T.;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Jul 2016, volume: 63, issue:7, pages: 623 - 627
Publisher: IEEE
 
» A 54- Inverter-Based Low-Noise Single-Ended to Differential VGA for Second Harmonic Ultrasound Probes in 65-nm CMOS
Abstract:
This brief presents an inverter-based low-noise single-ended to differential continuous-time variable gain amplifier (VGA) for 2-6-MHz second harmonic cardiac ultrasound imaging probes. The proposed VGA is based on a transimpedance amplifier and composed of resistive arrays and three equal inverters to form the resistive feedback loop. The inverters operate in the class C mode by being biased in the subthreshold region to improve both the power and noise performances of the VGA. The 6-bit thermometer resistive arrays can control the gain range from -1 to 21 dB for a 2-D piezoelectric transducer (PZT) model, and for a 50-Ω source resistor, the gain range is from 20 to 26 dB. The second harmonic distortion (HD2) is lower than -55 dB in most cases due to the single-ended to differential conversion, and the equivalent input referred noise is 7 nV/√Hz at 5 MHz with the maximum gain. The VGA is fabricated in 65-nm CMOS technology and has the power consumption of 54 μW at a supply voltage of 0.5 V. The die size of the VGA is 154 μm × 102 μm.
Autors: Wang, P.;Ytterdal, T.;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Jul 2016, volume: 63, issue:7, pages: 623 - 627
Publisher: IEEE
 
» A Bivariate - Distribution
Abstract:
In this paper, a bivariate - model is presented. Exact expressions for the 1) joint probability density function, the 2) joint cumulative distribution function, 3) joint arbitrary moments, and the 4) normalized envelope correlation coefficient are derived. The joint statistics are given in terms of their respective parameters and , with and arbitrary and . The parameter describing the correlation between - fading channels is then written in terms of the physical instances known to affect it in a wireless medium, namely, Doppler shift, the separation distance between two reception points, frequency, and delay spread. As an application example, the outage probability of a dual-branch selection-combining scheme is presented. The effect of correlation in the various aspects of system performance is then investigated. The validity of the analytical results is supported by reducing them to particular cases, for which results are available in the literature, and by means of simulation for the general cases.
Autors: Gomez Villavicencio, M.;de Souza, R.;de Souza, G.;Yacoub, M.;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jul 2016, volume: 65, issue:7, pages: 5737 - 5743
Publisher: IEEE
 
» A Bivariate - Distribution
Abstract:
In this paper, a bivariate - model is presented. Exact expressions for the 1) joint probability density function, the 2) joint cumulative distribution function, 3) joint arbitrary moments, and the 4) normalized envelope correlation coefficient are derived. The joint statistics are given in terms of their respective parameters and , with and arbitrary and . The parameter describing the correlation between - fading channels is then written in terms of the physical instances known to affect it in a wireless medium, namely, Doppler shift, the separation distance between two reception points, frequency, and delay spread. As an application example, the outage probability of a dual-branch selection-combining scheme is presented. The effect of correlation in the various aspects of system performance is then investigated. The validity of the analytical results is supported by reducing them to particular cases, for which results are available in the literature, and by means of simulation for the general cases.
Autors: Gomez Villavicencio, M.;de Souza, R.;de Souza, G.;Yacoub, M.;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jul 2016, volume: 65, issue:7, pages: 5737 - 5743
Publisher: IEEE
 
» A Centralized Preamble Detection-Based Random Access Scheme for LTE CoMP Transmission
Abstract:
For the coordinated multipoint (CoMP) transmission in Long-Term Evolution (LTE) systems, its performance is greatly impacted by the estimation of timing offsets (TOs) between cell-edge user equipment (UE) and transmit points, which is supposed to be dealt with by using the random access (RA) procedure. Available RA schemes for the CoMP transmission offer poor RA performance in terms of multiuser detection, TO estimation, power estimation, and access delays. To improve the RA performance and fully exploit the CoMP structure, in this paper, we propose a novel centralized parallel RA (CP-RA) scheme, which performs in threefold. First, a novel RA subchannel allocation scheme is proposed to suppress mutual interference between coordinated users and noncoordinated users. Second, an iterative parallel interference cancelation (IPIC)-based multiuser detection and estimation algorithm is proposed on the basis of the space-alternating generalized expectation–maximization (SAGE) algorithm. Finally, the coordinated diversity of the system structure could be exploited to implement centralized multiuser detection. Analyses and simulation results show that the proposed RA scheme is able to provide satisfied RA performance compared with existing schemes.
Autors: Wang, Q.;Ren, G.;Wu, J.;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jul 2016, volume: 65, issue:7, pages: 5200 - 5211
Publisher: IEEE
 
» A Closer Look at Demand Bids in California ISO Energy Market
Abstract:
One year of demand bids in the California energy market are analyzed and observations are reported on type, size, shape, and other characteristics of the bids. The implications of these observations, the underlying causes, and the potentials to improve demand bids by exploiting load flexibility are discussed.
Autors: Kohansal, M.;Mohsenian-Rad, H.;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jul 2016, volume: 31, issue:4, pages: 3330 - 3331
Publisher: IEEE
 
» A Common Model for the Approximate Analysis of Tandem Queueing Systems With Blocking
Abstract:
This work proposes a common model that unifies several approximate methods for the analysis of tandem queueing systems with blocking. Two abstract functions are introduced to characterize the relationship between starvation and blockage in neighboring machines. Using the functions, the equilibrium equations are determined, and a general procedure is developed to solve them. The sufficient conditions for the existence and uniqueness of a solution are obtained. More generally, the proposed model leads to the concept of a bidirectional cascade system, in which each subsystem has both forward and backward inputs and forward and backward outputs. Finally, the theory of the common model is applied to specific systems to demonstrate its applicability.
Autors: Li, L.;Qian, Y.;Yang, Y.;Du, K.;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Jul 2016, volume: 61, issue:7, pages: 1780 - 1793
Publisher: IEEE
 
» A Convex Characterization of Robust Stability for Positive and Positively Dominated Linear Systems
Abstract:
We provide convex necessary and sufficient conditions for the robust stability of linear positively dominated systems. In particular, we show that the structured singular value is always equal to its convex upper bound for nonnegative matrices and we use this result to derive necessary and sufficient Linear Matrix Inequality (LMI) conditions for robust stability that involve only the system's static gain. We show how this approach can be applied to test the robust stability of the Foschini–Miljanic algorithm for power control in wireless networks in presence of uncertain interference.
Autors: Colombino, M.;Smith, R.;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Jul 2016, volume: 61, issue:7, pages: 1965 - 1971
Publisher: IEEE
 
» A Crowdsourcing Worker Quality Evaluation Algorithm on MapReduce for Big Data Applications
Abstract:
Crowdsourcing is a new emerging distributed computing and business model on the backdrop of Internet blossoming. With the development of crowdsourcing systems, the data size of crowdsourcers, contractors and tasks grows rapidly. The worker quality evaluation based on big data analysis technology has become a critical challenge. This paper first proposes a general worker quality evaluation algorithm that is applied to any critical tasks such as tagging, matching, filtering, categorization and many other emerging applications, without wasting resources. Second, we realize the evaluation algorithm in the Hadoop platform using the MapReduce parallel programming model. Finally, to effectively verify the accuracy and the effectiveness of the algorithm in a wide variety of big data scenarios, we conduct a series of experiments. The experimental results demonstrate that the proposed algorithm is accurate and effective. It has high computing performance and horizontal scalability. And it is suitable for large-scale worker quality evaluations in a big data environment.
Autors: Dang, D.;Liu, Y.;Zhang, X.;Huang, S.;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Jul 2016, volume: 27, issue:7, pages: 1879 - 1888
Publisher: IEEE
 
» A Dataset for Breast Cancer Histopathological Image Classification
Abstract:
Today, medical image analysis papers require solid experiments to prove the usefulness of proposed methods. However, experiments are often performed on data selected by the researchers, which may come from different institutions, scanners, and populations. Different evaluation measures may be used, making it difficult to compare the methods. In this paper, we introduce a dataset of 7909 breast cancer histopathology images acquired on 82 patients, which is now publicly available from http://web.inf.ufpr.br/vri/breast-cancer-database. The dataset includes both benign and malignant images. The task associated with this dataset is the automated classification of these images in two classes, which would be a valuable computer-aided diagnosis tool for the clinician. In order to assess the difficulty of this task, we show some preliminary results obtained with state-of-the-art image classification systems. The accuracy ranges from 80% to 85%, showing room for improvement is left. By providing this dataset and a standardized evaluation protocol to the scientific community, we hope to gather researchers in both the medical and the machine learning field to advance toward this clinical application.
Autors: Spanhol, F.A.;Oliveira, L.S.;Petitjean, C.;Heutte, L.;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Jul 2016, volume: 63, issue:7, pages: 1455 - 1462
Publisher: IEEE
 
» A Detailed Comparison Between a Small-Slope Model of Acoustical Scattering From a Rough Sea Surface and Stochastic Modeling of the Coherent Surface Loss
Abstract:
The accurate modeling of underwater acoustical reflection from a wind-roughened ocean surface is a challenging problem. Some complicating factors are the presence of near-surface bubbles and the potential for shadowing of acoustical energy by parts of the surface itself. One essential factor, which is the subject of this paper, is the specular reflection of coherent plane waves at an ocean-like rough surface. We tested the accuracy of one rough surface reflection model, the small-slope approximation (SSA) approach as used by Williams (J. Acoust. Soc. Amer., vol. 116, no. 4, pp. 1975–1984, Oct. 2004), for scenarios for which scattering was entirely in the vertical plane. The SSA model was used to compute values of the coherent plane wave reflection loss per bounce for wind speeds between 5 and 12.5 m/s, frequencies between 1.5 and 9 kHz, and grazing angles between about 1 and 10 . These values were compared to those obtained from a Monte Carlo approach based on the parabolic equation (PE) method, where realistic ocean surfaces were generated based on the Pierson–Moskowitz spectrum for ocean surface heights. The SSA model compared favorably with the more rigorous PE method for most of the range of parameters considered. An approximation to the SSA model was derived for application to grazing angles less than particular values, and this approximation was shown to compare well with results from PE modeling.
Autors: Jones, A.D.;Duncan, A.J.;Maggi, A.L.;Bartel, D.W.;Zinoviev, A.;
Appeared in: IEEE Journal of Oceanic Engineering
Publication date: Jul 2016, volume: 41, issue:3, pages: 689 - 708
Publisher: IEEE
 
» A Digital PLL Using Oversampling Delta-Sigma TDC
Abstract:
A digital phase-locked loop (DPLL) using a delta-sigma time-to-digital converter is presented. This adopts the oversampling and feedforward techniques to improve the phase noise of the DPLL. The DPLL is fabricated in a 40-nm CMOS process. The proposed consumes 0.519 mW at a supply of 1.1 V, and its area is 0.0027 mm2. The measured output frequency is 4 GHz, and the division ratio is 128. The power of the DPLL is 3.51 mW, and its rms jitter is 861 fs.
Autors: Wei, Chih-Lu;Liu, Shen-Iuan;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Jul 2016, volume: 63, issue:7, pages: 633 - 637
Publisher: IEEE
 
» A Distributed Multi-Agent Based Emergency Control Approach Following Catastrophic Disturbances in Interconnected Power Systems
Abstract:
This paper presents a decentralized emergency control approach for preventing voltage instability by controlling the reactive power and voltage of the system. The proposed control algorithm is based on a distributed architecture of intelligent agents to identify the affected region and to activate timely countermeasures to achieve a fast and accurate response. By dividing the network into several areas, the voltage instability problem can be localized and countermeasures can be directed to the most affected area by the authorized local agent. This facilitates quick decision making within the system. To achieve effective voltage and reactive power support, a sensitivity based zone formation is proposed. The Nordic32 74-bus test system has been used for testing the proposed multi-agent emergency control (MAEC). The results from the case studies demonstrate the effectiveness of the proposed MAEC approach.
Autors: Islam, S.R.;Sutanto, D.;Muttaqi, K.M.;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jul 2016, volume: 31, issue:4, pages: 2764 - 2775
Publisher: IEEE
 
» A Dynamic Estimation of the Unsaturated Buffer in the IEEE 802.11 DCF Network: A Particle Filter Framework Approach
Abstract:
This paper proposes a particle filter framework to perform an online estimation of the unsaturated buffers of the stations in the IEEE 802.11 distributed coordination function (DCF) network. Using this framework, an access point can adapt flow control to its serving stations and configure related parameters dynamically, thus improving the system throughput and reducing the packet latency. Current research analyzing the unsaturated condition in the IEEE 802.11 DCF network is based on the steady-state model, whereas this proposed method is devoted to the dynamic estimation for the probability distribution of the unsaturated buffer in the stations, in either homogeneous or heterogeneous networks. This study also employs theoretical support from Bayesian inference to the particle-filtering algorithm. The estimation accuracy and effectiveness were evaluated via root mean square error (RMSE) and time complexity. Furthermore, we considered different network loads and convergence speeds in our analysis. Our analysis demonstrated that the proposed dynamic estimation scheme has greater awareness of the traffic changes in the varying wireless network when compared with the traditional static traffic model.
Autors: Chen, Yan-Bin;Lin, Guan-Yu;Wei, Hung-Yu;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jul 2016, volume: 65, issue:7, pages: 5397 - 5409
Publisher: IEEE
 
» A Fast and Power-Efficient Memory-Centric Architecture for Affine Computation
Abstract:
Affine computation is an important part in many vision applications. It is characterized by intensive computation and dependence of cascade memory access. This brief first implements operation fusion based on the data patterns to break the cascade dependence of memory access, and perform memory partitioning for memory-centric optimization to enhance data throughput and data reuse. Then, based on the memory-centric optimization, this brief proposes an affine computation architecture, using specialized pipeline design, which greatly improves computing efficiency. Experiments show that this work achieves higher performance on computing speed and power efficiency when compared with state-of-the-art methods.
Autors: Yin, S.;Ouyang, P.;Liu, L.;Wei, S.;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Jul 2016, volume: 63, issue:7, pages: 668 - 672
Publisher: IEEE
 
» A Fully Integrated Digital LDO With Coarse–Fine-Tuning and Burst-Mode Operation
Abstract:
The digital low dropout regulator (D-LDO) has drawn significant attention recently for its low-voltage operation and process scalability. However, the tradeoff between current efficiency and transient response speed has limited its applications. In this brief, a coarse–fine-tuning technique with burst-mode operation is proposed to the D-LDO. Once the voltage undershoot/overshoot is detected, the coarse tuning quickly finds out the coarse control word in which the load current should be located, with large power MOS strength and high sampling frequency for a fixed time. Then, the fine-tuning, with reduced power MOS strength and sampling frequency, regulates the D-LDO to the desired output voltage and takes over the steady-state operation for high accuracy and current efficiency. The proposed D-LDO is verified in a 65-nm CMOS process with a 0.01-mm2 active area. The measured voltage undershoot and overshoot are 55 and 47 mV, respectively, with load steps of 2 to 100 mA with a 20-ns edge time. The quiescent current is 82 , with a 0.43-ps figure of merit achieved. Moreover, the reference tracking speed is 1.5 .
Autors: Huang, M.;Lu, Y.;Sin, Sai-Weng;U., Seng-Pan;Martins, R.P.;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Jul 2016, volume: 63, issue:7, pages: 683 - 687
Publisher: IEEE
 
» A Game-Theoretic Foundation for the Maximum Software Resilience against Dense Errors
Abstract:
Safety-critical systems need to maintain their functionality in the presence of multiple errors caused by component failures or disastrous environment events. We propose a game-theoretic foundation for synthesizing control strategies that maximize the resilience of a software system in defense against a realistic error model. The new control objective of such a game is called -resilience. In order to be -resilient, a system needs to rapidly recover from infinitely many waves of a small number of up to close errors provided that the blocks of up to errors are separated by short time intervals, which can be used by the system to recover. We first argue why we believe this to be the right level of abstraction for safety critical systems when local faults are few and far between. We then show how the analysis of -resilience problems can be formulated as a model-checking problem of a mild extension to the alternating-time -calcul- s (AMC). The witness for resilience, which can be provided by the model checker, can be used for providing control strategies that are optimal with respect to resilience. We show that the computational complexity of constructing such optimal control strategies is low and demonstrate the feasibility of our approach through an implementation and experimental results.
Autors: Huang, C.-H.;Peled, D.A.;Schewe, S.;Wang, F.;
Appeared in: IEEE Transactions on Software Engineering
Publication date: Jul 2016, volume: 42, issue:7, pages: 605 - 622
Publisher: IEEE
 
» A Hardware-Software Approach for On-Line Soft Error Mitigation in Interrupt-Driven Applications
Abstract:
Integrity assurance of configuration data has a significant impact on microcontroller-based systems reliability. This is especially true when running applications driven by events which behavior is tightly coupled to this kind of data. This work proposes a new hybrid technique that combines hardware and software resources for detecting and recovering soft-errors in system configuration data. Our approach is based on the utilization of a common built-in microcontroller resource (timer) that works jointly with a software-based technique, which is responsible to periodically refresh the configuration data. The experiments demonstrate that non-destructive single event effects can be effectively mitigated with reduced overheads. Results show an important increase in fault coverage for SEUs and SETs, about one order of magnitude.
Autors: Martinez-Alvarez, A.;Restrepo-Calle, F.;Cuenca-Asensi, S.;Reyneri, L.M.;Lindoso, A.;Entrena, L.;
Appeared in: IEEE Transactions on Dependable and Secure Computing
Publication date: Jul 2016, volume: 13, issue:4, pages: 502 - 508
Publisher: IEEE
 
» A Holistic Modeling and Analysis of Optical–Electrical Interfaces for Inter/Intra-chip Interconnects
Abstract:
With the fast development of inter/intra-chip optical interconnects, the gap between the data rates of electrical interconnects and optical interconnects is continuously increasing. Electrical–optical (E-O) interfaces and optical–electrical (O-E) interfaces are a pair of components that convert data between parallel electrical interconnects and serial optical interconnects. This paper holistically models and analyzes E-O and O-E interfaces in terms of energy consumption, area, and latency. Traditional interfaces, where data are converted between parallel and serial ports by serializers and deserializers (SerDes), are studied. A new type of E-O and O-E interface, which serializes and deserializes data by optical weaving technologies, are proposed alongside. Traditional interfaces will become a bottleneck for the further development of optical interconnects in the near future because of the high energy consumption and large area of SerDes necessitating new technologies. Our analysis shows that optical weaving interfaces have a better overall performance than traditional interfaces. For example, if there are 64 parallel electrical interconnects and four optical wavelengths, optical weaving interfaces can achieve a 81.6% improvement in energy consumption and a 40.8% improvement in area, compared with traditional interfaces.
Autors: Wang, Z.;Xu, J.;Yang, P.;Duong, L.H.K.;Wang, Z.;Wang, X.;Wang, Z.;Li, H.;Maeda, R.K.V.;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Jul 2016, volume: 24, issue:7, pages: 2462 - 2474
Publisher: IEEE
 
» A Hybrid Optimal Control Approach to Fuel-Efficient Aircraft Conflict Avoidance
Abstract:
We formulate fuel-optimal conflict-free aircraft trajectory planning as a hybrid optimal control problem. The discrete modes of the hybrid system capture the air traffic procedures for conflict resolution, e.g., speed and turn advisories. To solve problems of realistic dimensions arising from air traffic sector planning, we formulate a numerically tractable approach to solve the hybrid optimal control problem. The approach is based on introducing binary functions for each mode, relaxing the binary functions and including a penalty term on the relaxation. The transformed and discretized problem is a nonlinear program. We use the approach on a realistic case study with seven aircraft within an air traffic control sector, in which we find minimum-fuel conflict-free trajectories.
Autors: Soler, M.;Kamgarpour, M.;Lloret, J.;Lygeros, J.;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: Jul 2016, volume: 17, issue:7, pages: 1826 - 1838
Publisher: IEEE
 
» A Low-Complexity Interference-Aware Sphere Detector for Imperfect Channel Estimates
Abstract:
In practical applications, an imperfect channel estimate over a noisy channel is inevitable. This paper investigates an interference-aware receiver in which colored-estimation-noise-based maximum-likelihood (CEN-ML) detection is employed to mitigate the impact of imperfect channel estimates. It is shown that the CEN-ML detection, which treats the channel estimation errors as colored noise, has superior performance and is robust to imperfect channel estimation. However, a CEN-ML interference-aware detector usually requires computational efforts that are too complex for multiple-input–multiple-output (MIMO) interference-limited systems. To reduce the complexity, this paper proposes new methods for both the preprocessing and tree-search stages of an interference-aware sphere detector (SD). First, a channel extended matrix is constructed using the information from channel estimation errors in a preprocessing stage. The channel extension model can reduce the complexity without performance loss. Second, two tree pruning (TP) criteria are developed in a tree-search stage to make the implementation of the CEN-ML SD feasible. The first criterion is based on a lower bound of the CEN-ML metric and can achieve the same result as the optimal brute-force method. The second criterion is derived from an approximated metric and can further reduce the complexity with small performance loss. Simulation results for typical Third-Generation Partnership Project Long-Term Evolution (LTE)/LTE-Advanced scenarios show that the new methods provide the ability to deal with the channel estimation errors and to achieve a better tradeoff between complexity and performance (e.g., in terms of throughput or error rate) in interference-limited scenarios. The proposed low-complexity CEN-ML SD can have a gain of more than 10 dB than the other investigated detection for 16-ary quadrature amplitude modulation (QAM) or 64-QAM at a target coded block error rate (BLER) of .
Autors: Zhou, G.;Xu, W.;Bauch, G.;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jul 2016, volume: 65, issue:7, pages: 5337 - 5348
Publisher: IEEE
 
» A Low-Latency QRD-RLS Architecture for High-Throughput Adaptive Applications
Abstract:
A novel architecture for QR decomposition-based recursive least squares is presented. It offers low latency for applications where the channel equalization and adaptive filtering are mandatory. This approach reduces the computations by rewriting the equations in a manner that lets intense hardware resource sharing by reusing similar values in different computations. Moreover, precision range conversion allows for combining complex operations such as root square and division with minimum effect on the overall quantization error. Hence, an efficient lookup table-based solution has highly enhanced the performance of the design by 2.7 times with respect to the previous works.
Autors: Alizadeh, M.;Bagherzadeh, J.;Sharifkhani, M.;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Jul 2016, volume: 63, issue:7, pages: 708 - 712
Publisher: IEEE
 
» A Low-Power Class-AB Gm-Based Amplifier With Application to an 11-bit Pipelined ADC
Abstract:
A Gm-based amplifier is proposed for the use in low-voltage and low-power switched-capacitor circuits. At the input stage of the amplifier, a common-mode current-suppression scheme effectively suppresses the common-mode current with the differential-mode current even amplified, resulting in decrease in dc power consumption. At the output stage of the amplifier, a self-biased cascode configuration adaptively changes bias voltages to achieve both the cascode operation for high gain and digital switching operation for fast transients. The proposed amplifier is applied to a design of an 11-bit pipelined ADC with a 0.13- CMOS process. The implemented analog-to-digital converter consumes 80 from a single 0.7 V supply at 2.5 MS/s. It achieves an effective number of bit of 9.72 bit without any calibration scheme and a figure of merit of 37.8 fJ/c-s at near Nyquist rate.
Autors: Suh, Y.;Choi, S.;Sim, J.-Y.;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Jul 2016, volume: 24, issue:7, pages: 2562 - 2569
Publisher: IEEE
 
» A Maximum-Likelihood Channel Estimator for Self-Interference Cancelation in Full-Duplex Systems
Abstract:
Operation of full-duplex systems requires efficient mitigation of the self-interference signal caused by the simultaneous transmission/reception. In this paper, we propose a maximum-likelihood (ML) approach to jointly estimate the self-interference and intended channels by exploiting its own known transmitted symbols and both the known pilot and unknown data symbols from the other intended transceiver. The ML solution is obtained by maximizing the ML function under the assumption of Gaussian received symbols. A closed-form solution is first derived, and subsequently, an iterative procedure is developed to further improve the estimation performance at moderate-to-high signal-to-noise ratios (SNRs). We establish the initial condition to guarantee the convergence of the iterative algorithm to the ML solution. In the presence of considerable phase noise from the oscillators, a phase noise estimation method is proposed and combined with the ML channel estimator to mitigate the effects of the phase noise. Illustrative results show that the proposed methods offer good cancelation performance close to the Cramer–Rao bound (CRB).
Autors: Masmoudi, A.;Le-Ngoc, T.;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jul 2016, volume: 65, issue:7, pages: 5122 - 5132
Publisher: IEEE
 
» A Methodology to Design Spin-Wave-Based Logic Gates in a Single Ferromagnetic Nanostripe Using Spin-Transfer Torque Effects
Abstract:
We present a methodology design of spin-wave-based multi-input logic gates by applying a local spin-polarized current on a single ferromagnetic stripe. Micromagnetic simulation shows that the phase of propagating spin waves in a single ferromagnetic nanostripe can be shifted by /5 without decreasing its amplitude when they pass through an area with nonlinear internal field. The methodology adopting spin-transfer torque effects to fulfill spin-wave-based multi-input logic gates is demonstrated in a single ferromagnetic waveguide. The structure of designed logic gates can be simplified significantly compared with the prototype Mach–Zehnder-type interferometer type gates.
Autors: Chen, X.;Wang, Q.;Bai, F.;Tang, X.;Zhang, H.;Zhong, Z.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Jul 2016, volume: 52, issue:7, pages: 1 - 4
Publisher: IEEE
 
» A Mobile Kalman-Filter Based Solution for the Real-Time Estimation of Spatio-Temporal Pub _newline Gait Parameters
Abstract:
Gait impairments are among the most disabling symptoms in several musculoskeletal and neurological conditions, severely limiting personal autonomy. Wearable gait sensors have been attracting attention as diagnostic tool for gait and are emerging as promising tool for tutoring and guiding gait execution. If their popularity is continuously growing, still there is room for improvement, especially towards more accurate solutions for spatio-temporal gait parameters estimation. We present an implementation of a zero-velocity-update gait analysis system based on a Kalman filter and off-the-shelf shoe-worn inertial sensors. The algorithms for gait events and step length estimation were specifically designed to comply with pathological gait patterns. More so, an Android app was deployed to support fully wearable and stand-alone real-time gait analysis. Twelve healthy subjects were enrolled to preliminarily tune the algorithms; afterwards sixteen persons with Parkinson's disease were enrolled for a validation study. Over the 1314 strides collected on patients at three different speeds, the total root mean square difference on step length estimation between this system and a gold standard was 2.9%. This shows that the proposed method allows for an accurate gait analysis and paves the way to a new generation of mobile devices usable anywhere for monitoring and intervention.
Autors: Ferrari, A.;Ginis, P.;Hardegger, M.;Casamassima, F.;Rocchi, L.;Chiari, L.;
Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Publication date: Jul 2016, volume: 24, issue:7, pages: 764 - 773
Publisher: IEEE
 
» A Multi-Timescale Quasi-Dynamic Model for Simulation of Cascading Outages
Abstract:
Many blackouts in electric power grids throughout the world are caused by cascading outages, which often involve complex processes in various timescales. The multi-timescale nature of cascading outages makes conventional quasi-static simulation methods inaccurate in characterizing actual evolution of outages. This paper proposes a multi-timescale cascading outage model using a quasi-dynamic simulation method. The model establishes a framework for simulating interactions among dynamics in quite different timescales. It realizes simulation of cascading outages with representation of time evolution, so it overcomes ambiguity of time in conventional cascading outage models and hence has better practicality. Moreover, the model considers dynamics, e.g., load variation and generator excitation protection which affect voltage and reactive power profiles. Also, an improved re-dispatch model based on sensitivity is proposed. These improvements facilitate better simulation for a realistic power system. Also, dynamic simulation can be flexibly incorporated into the simulation of short-term processes in this model as needed. Case studies with the proposed multi-timescale model on the IEEE 30-bus system discuss the role of generator protection in cascading outage evolution, and analyze stage characteristics in outages. The multi-timescale model is also demonstrated on a reduced 410-bus US-Canada northeast power grid. Moreover, impacts from dispatchers' involvements are analyzed.
Autors: Yao, R.;Huang, S.;Sun, K.;Liu, F.;Zhang, X.;Mei, S.;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jul 2016, volume: 31, issue:4, pages: 3189 - 3201
Publisher: IEEE
 
» A Multicircuit Simulator Based on Inverse Jacobian Matrix Reuse
Abstract:
This paper proposes a technique, GALAXY, to speed up multicircuit simulation, where each circuit under simulation is identical in schematic but different in some parameters. GALAXY is based on the successive chord method, where the inverse Jacobian matrix () is reused to simulate many circuits whose solutions are similar. GALAXY also speeds up single-circuit simulation by reusing between consecutive time steps. Compared with a traditional Newton–Raphson (NR) simulator, on average, GALAXY reduces runtime of single-circuit and multicircuit simulation by 44% and 71%, without loss of accuracy. The number of NR iterations is reduced by 78%.
Autors: Lee, H.I.;Han, C.;Li, C.;
Appeared in: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Publication date: Jul 2016, volume: 35, issue:7, pages: 1130 - 1137
Publisher: IEEE
 
» A Multilevel Class-D CMOS Power Amplifier for an Out-Phasing Transmitter With a Nonisolated Power Combiner
Abstract:
This brief presents a nonisolated multilevel linear amplifier with nonlinear component (LINC) power amplifier (PA) implemented in a standard 0.18- complementary metal–oxide–semiconductor process. Using a nonisolated power combiner, the overall power efficiency is increased by reducing the wasted power at the combined out-phased signal; however, the efficiency at low power still needs to be improved. To further improve the efficiency of the low-power (LP) mode, we propose a multiple-outputpower-level LINC PA, with load modulation implemented by switches. In addition, analysis of the proposed design on the system level as well as the circuit level was performed to optimize its performance. The measurement results demonstrate that the proposed technique maintains more than 45% power-added efficiency (PAE) for peak power at 21 dB for the high-power mode and 17 dBm for the LP mode at 600 MHz. The PAE for a 6-dB peak-to-average ratio orthogonal frequency-division multiplexing modulated signal is higher than 24% PAE in both power modes. To the authors' knowledge, the proposed output-phasing PA is the first implemented multilevel LINC PA that uses quarter-wave lines without multiple power supply sources.
Autors: Hur, J.;Kim, H.;Lee, O.;Kim, Kwan-Woo;Lim, K.;Lee, Chang-Ho;Laskar, J.;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Jul 2016, volume: 63, issue:7, pages: 618 - 622
Publisher: IEEE
 
» A New Coreless Axial Flux Interior Permanent Magnet Synchronous Motor With Sinusoidal Rotor Segments
Abstract:
Axial flux permanent magnet (AFPM) motors are frequently used in many applications. Axial gap coreless motors with surface-mounted magnets are the most noteworthy ones due to their potentially higher efficiency and smaller axial length. In this paper, a new spoke-type AFPM coreless disk motor with dual rotor and single stator is proposed with sinusoidal rotor segments. This new disk-type motor is an interior PM (IPM) motor with spoke-type rotor and variable air gap to obtain sinusoidal back Electro-Motive Force waveform. It is shown that it is possible to increase the air-gap flux density in the proposed new coreless AF-IPM motor and increase the torque output compared with the conventional surface-mounted AFPM motors.
Autors: Aydin, M.;Gulec, M.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Jul 2016, volume: 52, issue:7, pages: 1 - 4
Publisher: IEEE
 
» A New Fast and Area-Efficient Adder-Based Sign Detector for RNS {}
Abstract:
The moduli set {, , } has been widely used in residue number system (RNS)-based computations. Its sign extraction problem, albeit fundamentally important in magnitude comparison and other difficult algorithms in RNS, has received considerably less attention than its scaling and reverse conversion problems. This brief presents a new algorithm for the design of a fast adder-based sign detector. The circuit is greatly simplified by shrinking the dynamic range to eliminate large modulo operations with the help of the new Chinese remainder theorem. Our synthesis results with the 65-nm CMOS standard cell library show that the proposed design outperforms all the existing adder-based sign detectors reported for this moduli set in area and speed for ranges from 5 to 25 in the step of 5.
Autors: Kumar, S.;Chang, C.-H.;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Jul 2016, volume: 24, issue:7, pages: 2608 - 2612
Publisher: IEEE
 
» A New Generalized Robust Predictive Current Control for Grid-Connected Inverters Compensates Anti-Aliasing Filters Delay
Abstract:
In this paper, a new predictive control for grid-connected inverters is presented, which provides the best performance in terms of transient response and stability margins when analog filters in current sensing circuits are used. These filters are necessary to avoid aliasing in the A/D conversion process, which causes an important ripple on injected current into the grid and increases the total harmonic distortion. However, predictive controls are very sensitive to delays on the acquisitions, so when such anti-aliasing filters are used a reduction of stability margins is produced and the transient response is affected. The proposed predictive control allows to compensate the effect of the filter, for any order and cutoff frequency, providing the best transient response in the reference tracking and the highest stability margins. Furthermore, a modification on the adaptive strategy of current error is proposed, which allows to work with single-phase grid-connected inverters. The proposed predictive control has been tested on a 3.3-kVA single-phase grid-connected inverter with LCL filter, using different anti-aliasing filters, obtaining in all cases, better results than those offered by other predictive controls recently published.
Autors: Castello, J.;Espi, J.M.;Garcia-Gil, R.;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Jul 2016, volume: 63, issue:7, pages: 4485 - 4494
Publisher: IEEE
 
» A New Notion of Effective Resistance for Directed Graphs—Part I: Definition and Properties
Abstract:
The graphical notion of effective resistance has found wide-ranging applications in many areas of pure mathematics, applied mathematics and control theory. By the nature of its construction, effective resistance can only be computed in undirected graphs and yet in several areas of its application, directed graphs arise as naturally (or more naturally) than undirected ones. In Part I of this work, we propose a generalization of effective resistance to directed graphs that preserves its control-theoretic properties in relation to consensus-type dynamics. We proceed to analyze the dependence of our algebraic definition on the structural properties of the graph and the relationship between our construction and a graphical distance. The results make possible the calculation of effective resistance between any two nodes in any directed graph and provide a solid foundation for the application of effective resistance to problems involving directed graphs.
Autors: Young, G.F.;Scardovi, L.;Leonard, N.E.;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Jul 2016, volume: 61, issue:7, pages: 1727 - 1736
Publisher: IEEE
 
» A New Shape Feature for Vehicle Classification in Thermal Video Sequences
Abstract:
Since thermal images represent only the temperature difference between objects and background and they have more blurred edges than color images, the segmented images from them have noisy object boundaries. Therefore, the well-known features developed for color images may not work well with thermal images. To overcome these limitations of thermal images, we propose a novel feature extraction method based on the target trait context (TTC). A robust keypoint detector is also proposed by analyzing the included angle moments of the object boundary points. At each keypoint, we define the boundary shape context and the normalized intensity context, which contain shape information and thermal distribution, respectively, of the object. These two contexts are combined to form a new feature set, the TTC. To validate our proposed feature extraction method, the keypoint repeatability test and the classification performance test were performed and compared with those from the previous methods. The experiment results show that the proposed feature works well for thermal video sequences and outperforms the previous methods in classification performance.
Autors: Yang, D.;Park, H.;
Appeared in: IEEE Transactions on Circuits and Systems for Video Technology
Publication date: Jul 2016, volume: 26, issue:7, pages: 1363 - 1375
Publisher: IEEE
 
» A Non-Resonant Magnetoelectric Energy Converter for Scavenging Magnetic Field Energy From Two-Wire Power Cords
Abstract:
A non-resonant magnetoelectric (ME) energy converter is presented for scavenging power-frequency magnetic field energy from two-wire power cords. The device is composed of a Terfenol-D/Pb(Mg1/3Nb2/3)O3-PbTiO3(PMNT)/Terfenol-D ME transducer, a NdFeB manget, and E-shaped magnetic yokes. The ME transducer, the magnet, and the magnetic yokes constitute a magnetic circuit, and the bias magnetic field of the ME transducer can be tuned by adjusting the contact area between the magnet and the magnetic yokes to obtain optimal power output. Meanwhile, the power-frequency magnetic field of the power cord is concentrated to the ME transducer by the magnetic yokes, which can potentially improve the power output of the device. Experiments were undertaken to evaluate the potential of energy scavenging from nearby power cords. When coupled to an appliance power cord carrying a current of 16 A, the device generated a rms voltage of 2.46 V and a maximum power of W with a matching load resistance of . At a duration of 205 ms, the device can supply power for a temperature-humidity wireless sensor through an up-conversion management circuit with the power consumption of 90 mW at transmitting and 18 mW at receiving.
Autors: He, W.;Qu, C.;Zhang, J.;Wu, J.;Peng, J.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Jul 2016, volume: 52, issue:7, pages: 1 - 4
Publisher: IEEE
 
» A Nonmonetary QoS-Aware Auction Framework Toward Secure Communications for Cognitive Radio Networks
Abstract:
This paper investigates the secure communication issue for cognitive radio networks with nonaltruistic users. The design objective is to improve the secrecy rate of the primary user (PU) and, at the same time, create transmission opportunities for the secondary users (SUs) to satisfy their diversified quality-of-service (QoS) demands. To achieve this goal, we propose a novel nonmonetary trading model, where the users are incentivized to participate in the market by a barter-like resource-to-resource exchange. Specifically, the PU leverages the assistance of the SU in the form of cooperative forwarding or friendly jamming and yields part of the spectrum accessing time to the aided SU. The proposed spectrum auction framework jointly formulates the optimal cooperator selection and the corresponding resource allocation problems by taking into consideration the QoS demands of individual users. The proposed framework ensures that bidding truthfully is the dominant strategy for all bidders and, thus, is invulnerable to market manipulation and eliminates the overhead of strategizing over other bidders. Simulation results reveal that the proposed framework could provide substantial gains for both the PU and the aided SU.
Autors: Wang, X.;Ji, Y.;Zhou, H.;Li, J.;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jul 2016, volume: 65, issue:7, pages: 5611 - 5623
Publisher: IEEE
 
» A Nonzero Sum Differential Game of BSDE With Time-Delayed Generator and Applications
Abstract:
In this technical note, a nonzero sum differential game is studied, where the state dynamics follows a backward stochastic differential equation with time-delayed generator. An Arrow's sufficient condition for open-loop equilibrium point is proved. A linear-quadratic differential game and a pension fund management problem with time-delayed surplus are discussed as the applications of the sufficient optimality condition.
Autors: Shi, J.;Wang, G.;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Jul 2016, volume: 61, issue:7, pages: 1959 - 1964
Publisher: IEEE
 
» A Novel Coaxial Magnetic Gear and Its Integration With Permanent-Magnet Brushless Motor
Abstract:
A magnetic geared machine (MGM) is believed to be a promising candidate for high-torque direct-drive application. One of the key issues for developing MGMs is how to resolve the contradiction between the good performance and the complex structure. This paper aims at proposing a novel coaxial magnetic gear (CMG), which will not increase the mechanical complexity after integration with a permanent magnet (PM) brushless machine. The prominent feature of the proposed CMG is the introduction of the stator with modulating teeth, which function as the same as the modulating pole-pieces in the conventional CMG. The integrated MGM can then be achieved by inserting the armature windings into the stator slots. The configuration, harmonic analysis, and torque capability of the proposed CMG are compared with the conventional CMG. The operating principle and electromagnetic performance of the proposed MGM are investigated by dividing it into one vernier PM machine, one PM brushless machine and one proposed CMG. The results show that the developed integrated MGM exhibits good torque capability and power factor.
Autors: Zhang, X.;Liu, X.;Chen, Z.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Jul 2016, volume: 52, issue:7, pages: 1 - 4
Publisher: IEEE
 
» A Novel Control Strategy for Online Harmonic Compensation in Parametrically Unbalanced Induction Motor
Abstract:
Inverter-fed motor drive operating an unbalanced induction motor (IM) has high harmonic content which inflicts large torque ripple on the load. Dead short circuit and incipient or partial short circuit in motor stator windings lead to asymmetry in the machine parameters. Consequently, an imbalance in the voltage supply worsens the condition deteriorating the optimal performance of the drive-based motor due to the injection of both increased time and spatial harmonics. It is of primary importance that these discrepancies are taken care of while modeling a more fault tolerant, reduced harmonics drive system. This paper proposes a novel control strategy to minimize torque ripple by considering the time harmonics produced due to imbalance in inverter voltage and parameters of the faulty IM, and the estimated space harmonics from the measured magnetic flux density in a transient magnetic phenomenon. The proposed control strategy has been implemented on an unbalanced aluminum-rotor IM with online monitoring of unhealthy conditions and feeding it to the harmonic compensation block of the drive system.
Autors: Ghosh, E.;Mollaeian, A.;Hu, W.;Kar, N.C.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Jul 2016, volume: 52, issue:7, pages: 1 - 4
Publisher: IEEE
 
» A Novel Current Injection-Based Online Parameter Estimation Method for PMSMs Considering Magnetic Saturation
Abstract:
This paper studies the online parameter estimation of permanent magnet synchronous motor (PMSM) with the consideration of magnetic saturation and proposes a novel current injection method to estimate parameters, including winding resistances, -axis inductances, and rotor flux. During the current injection, the inductances will vary due to magnetic saturation, neglecting which will cause great estimation error especially in the inductance estimation. This paper proposes to use simplified equations to model the self- and cross-saturation effects during the current injection. By incorporating this saturation model into the PMSM steady-state equations, the varying -axis inductances due to magnetic saturation as well as the rotor flux can be accurately estimated. In addition, the estimation of winding resistance is independent of other parameters and does not get affected by the magnetic saturation. The proposed approach is validated through both the numerical and experimental studies on a laboratory interior PMSM.
Autors: Feng, G.;Lai, C.;Kar, N.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Jul 2016, volume: 52, issue:7, pages: 1 - 4
Publisher: IEEE
 
» A Novel Dual Three-Phase Permanent Magnet Synchronous Motor With Asymmetric Stator Winding
Abstract:
Although three-phase permanent magnet (PM) motors are dominant in industry, multi-phase PM synchronous motors present higher torque-to-weight ratios, better efficiency, and low torque ripple compared with three-phase conventional PM motors. These features make fault-tolerant multi-phase PM motors become attractive for safety-critical applications. In this paper, a novel PM multi-phase motor design with a dual three-phase asymmetric stator winding is proposed. The winding structure of the proposed motor is unconventional due to selected slot–pole combinations. Therefore, an asymmetric winding is needed. The detailed finite-element analysis of the proposed motor and a performance comparison between the conventional integer-slot (72-slot/12-pole motor) with symmetric winding and the unconventional fractional-slot (78-slot/12-pole motor) PM motors with asymmetric windings is performed to see the benefits of the proposed motor. It was shown that the novel unconventional multi-phase PM motor has excellent torque quality and slightly higher torque density levels.
Autors: Demir, Y.;Aydin, M.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Jul 2016, volume: 52, issue:7, pages: 1 - 5
Publisher: IEEE
 
» A Novel Quasi-Decentralized Functional Observer Approach to LFC of Interconnected Power Systems
Abstract:
This paper presents a novel functional observer based quasi-decentralized load frequency control scheme for power systems. Based on functional observers theory, quasi-decentralized functional observers are designed to implement any given state feedback controller. The designed functional observers are decoupled from each other and have a simpler structure in comparison to the state observer based schemes. The proposed functional observer scheme is applied to a complex nonlinear power system and the proposed design method is based on the entire network topology.
Autors: Fernando, T.;Emami, K.;Yu, S.;Iu, H.H.-C.;Wong, K.P.;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jul 2016, volume: 31, issue:4, pages: 3139 - 3151
Publisher: IEEE
 
» A Novel Recommendation Model Regularized with User Trust and Item Ratings
Abstract:
We propose TrustSVD, a trust-based matrix factorization technique for recommendations. TrustSVD integrates multiple information sources into the recommendation model in order to reduce the data sparsity and cold start problems and their degradation of recommendation performance. An analysis of social trust data from four real-world data sets suggests that not only the explicit but also the implicit influence of both ratings and trust should be taken into consideration in a recommendation model. TrustSVD therefore builds on top of a state-of-the-art recommendation algorithm, SVD++ (which uses the explicit and implicit influence of rated items), by further incorporating both the explicit and implicit influence of trusted and trusting users on the prediction of items for an active user. The proposed technique is the first to extend SVD++ with social trust information. Experimental results on the four data sets demonstrate that TrustSVD achieves better accuracy than other ten counterparts recommendation techniques.
Autors: Guo, G.;Zhang, J.;Yorke-Smith, N.;
Appeared in: IEEE Transactions on Knowledge and Data Engineering
Publication date: Jul 2016, volume: 28, issue:7, pages: 1607 - 1620
Publisher: IEEE
 
» A Novel Regularization Technique for Microendoscopic Electrical Impedance Tomography
Abstract:
A novel regularization technique is developed for end-fired microendoscopic electrical impedance tomography using the dual-mesh method. The new regularization technique coupled with appropriate forward modeling and inverse mesh design is shown to produce dramatically improved reconstructions over previous methods. 3D absolute and difference reconstructions from measured saline tank and ex vivo adipose and muscle tissue experiments are used to validate the approach. The ex vivo experiments are used as a surrogate for prostate tissue, which is the primary clinical application for the probe. Inclusion center of mass errors were less than 0.47 mm for tank experiments with inclusion depths and radial offsets ranging less than 3 mm and 1.5 mm, respectively. Absolute 3D reconstructions on the tissue show quantitatively good accuracy and the ability to spatially distinguish small tissue features (adipose strands of approximately 2.5 mm in width). The reconstruction algorithm developed provides strong evidence for the promise of surgical margin detection using microendoscopic EIT.
Autors: Murphy, E.;Mahara, A.;Halter, R.;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Jul 2016, volume: 35, issue:7, pages: 1593 - 1603
Publisher: IEEE
 
» A Novel Technique for Two-Phase BLDC Motor to Avoid Demagnetization
Abstract:
Conventional permanent magnet (PM) motors operate in both magnetizing (pull) process and reversible demagnetizing (push) process on the recoil line of magnets. Therefore, thin-surface PMs may easily undergo a risk of demagnetization at the push process under certain fault conditions, which lead to deterioration of motor performance. Thus, thick magnets, whereas contributing the significantly high cost, are usually used to minimize this risk in the PM motors. In this paper, a novel operation technique, that involves only the pull process, has been proposed for a unique design of two-phase brushless DC motor to avoid the irreversible demagnetization of the magnets. The motor, operated only in the pull process, is kept away from the push process of the operation. Therefore, the motor sustains its initial magnetic operating point above the knee point during the normal operation as well as under the short circuit fault conditions. Finite-element analysis is performed to validate the concept of the proposed technique.
Autors: Yazdan, T.;Zhao, W.;Lipo, T.;Kwon, B.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Jul 2016, volume: 52, issue:7, pages: 1 - 4
Publisher: IEEE
 
» A Novel Test Method for Metallic CNTs in CNFET-Based SRAMs
Abstract:
Static random access memories (SRAMs) built on carbon nanotube field effect transistors (CNFETs) are promising alternatives to conventional CMOS-based SRAMs, due to their advantages in terms of power consumption and noise immunity. However, the nonideal carbon nanotube (CNT) fabrication process generates metallic-CNTs (m-CNTs) along with semiconductor-CNTs, leading to correlated faulty cells along the growth direction of the m-CNTs. In this paper, we propose a novel low-cost test solution to detect such faults. Instead of using conventional March test to test each and every SRAM cell, we selectively test certain SRAM cells and judiciously skip testing other SRAM cells between the selected cells. To ensure high fault coverage, we propose three jump test algorithms for different CNFET-SRAM layouts. Moreover, we model m-CNT-induced SRAM faults and characterize their distribution in the SRAM array. Experimental results show that the proposed solutions are able to achieve high fault coverage with low test cost.
Autors: Li, T.;Xie, F.;Liang, X.;Xu, Q.;Chakrabarty, K.;Jing, N.;Jiang, L.;
Appeared in: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Publication date: Jul 2016, volume: 35, issue:7, pages: 1192 - 1205
Publisher: IEEE
 
» A Passive Electric Current Sensor Based on Ferromagnetic Invariant Elastic Alloy, Piezoelectric Ceramic, and Permalloy Yoke
Abstract:
This paper presented a passive current sensor in an electric power grid. The sensor consists of an iron–nickel-based ferromagnetic invariant elastic alloy (FIEA) beam with high quality factor (-factor), piezoelectric ceramic Pb(Zr,Ti)O3 (PZT8), and a Permalloy yoke. The beam bends in the magnetic field of a current-carrying wire as a result of the magnetostriction of the FIEA, and the PZT8 produces a voltage proportional to the electric current in the wire. The electric current sensitivity is potentially improved due to the high -factor of the FIEA/PZT8 beam and the concentration effect of the Permalloy yoke. Experimental data are taken to evaluate the feasibility of the current sensor. At the power frequency of 50 Hz, the sensor shows the linear sensitivities of 300.5, 177.9, 119.2, and 88.8 mV/A from 0.2 to 5 A when the separating distances are 6, 10, 15, and 20 mm, respectively. The performances indicate that the proposed device is promising for power-frequency current sensing applications.
Autors: He, W.;Zhang, J.;Qu, C.;Wu, J.;Peng, J.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Jul 2016, volume: 52, issue:7, pages: 1 - 4
Publisher: IEEE
 
» A Performance Debugging Framework for Unnecessary Lock Contentions with Record/Replay Techniques
Abstract:
Locks have been widely used as an effective synchronization mechanism among processes and threads. However, we observe that, a large number of false inter-thread dependencies (i.e., unnecessary lock contentions) exist during the program execution on multicore processors, incurring significant performance overhead. This paper presents a performance debugging framework, PerfPlay, to facilitate the identification of unnecessary lock contentions and to guide programmers to improve the program performance by eliminating the unnecessary lock contentions. Since the performance debugging of unnecessary lock contentions is input-sensitive, we first identify the representative inputs for performance debugging. Next, PerfPlay quantifies the performance impact of unnecessary lock contention code regions for each candidate input. Taking into account conflicting attribute of performance impact and input coverage in the real world, we finally make the tradeoff between performance impact and input coverage to recommend the optimal unnecessary lock contention code regions. Our final results on five real-world programs and PARSEC benchmarks demonstrate the significant performance overhead of unnecessary lock contentions, and the effectiveness of PerfPlay in troubleshooting the target unnecessary lock contention code regions with the consideration of both performance impact and input coverage.
Autors: Liao, X.;Zheng, L.;He, B.;Wu, S.;Jin, H.;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Jul 2016, volume: 27, issue:7, pages: 1889 - 1901
Publisher: IEEE
 
» A Provenance-Aware Access Control Framework with Typed Provenance
Abstract:
Provenance is a directed graph that captures historical information about data items in Provenance-Aware Systems (PAS). A variety of access control models and policy languages specific to PAS have been recently discussed in literature. However, it is still not clear how to efficiently specify provenance-aware access control policies and how to effectively enforce these policies with respect to complex provenance graph that can only be captured at run-time. To this end, we design and implement a provenance-aware access control framework with a layered architecture that features an abstract layer, including a Typed Provenance Model (TPM) and a set of TPM interpreters. TPM includes a set of abstract provenance types enabling efficient specification of provenance-aware policies. New provenance types can be composed of extant ones for specifying new policies. TPM interpreters can be integrated to enable the policy enforcement with respect to provenance graphs in different physical representations. By treating provenance types as special attributes, the proposed framework enables an adoption of provenance-aware access control in existing attribute-based access control frameworks, such as XACML-compliant ones. We implement the proposed framework by extending SUN's XACML implementation and show that it facilitates the specification of provenance-aware policies in XACML with minor extensions. We also analyze the performance of the proposed framework.
Autors: Sun, L.;Park, J.;Nguyen, D.;Sandhu, R.;
Appeared in: IEEE Transactions on Dependable and Secure Computing
Publication date: Jul 2016, volume: 13, issue:4, pages: 411 - 423
Publisher: IEEE
 
» A Randomized Linear Algorithm for Clock Synchronization in Multi-Agent Systems
Abstract:
A broad family of randomized clock synchronization protocols based on a second order consensus algorithm is proposed. Under mild conditions on the graph connectivity, it is proved that the parameters of the algorithm can always be tuned in such a way that the clock synchronization is achieved in the probabilistic mean—square sense. This family of algorithms contains, as particular cases, several known approaches which range from distributed asynchronous to hierarchical synchronous protocols. This is illustrated by specializing the algorithm for the well-known broadcast and gossip scenarios in wireless communications, and for the standard hierarchical protocol used in the context of wired communications in data networks. In these cases, we show how the feasible range for the algorithm parameters can be explicitly computed. Finally, the performance of this strategy is validated by actual implementation in a real testbed and by numerical simulations.
Autors: Bolognani, S.;Carli, R.;Lovisari, E.;Zampieri, S.;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Jul 2016, volume: 61, issue:7, pages: 1711 - 1726
Publisher: IEEE
 
» A Resistorless Low-Power Voltage Reference
Abstract:
A novel low-power temperature-stable voltage reference without resistors is presented in this brief, which is compatible with standard CMOS technology. In order to reduce the temperature nonlinearity in the proposed voltage reference, threshold voltage and a proportional-to-absolute-temperature voltage form the basic linear-temperature components, which are achieved by resistorless threshold voltage extractor and asymmetric differential difference amplifier. Moreover, a self-biased current source with feedback is used to provide stable bias currents for the whole voltage reference, which can improve the power-supply noise attenuation (PSNA) with reduced current mirror errors. Verification results of the proposed voltage reference implemented with 0.18- CMOS technology demonstrate that the temperature coefficient of 14.1 ppm/°C with a temperature range of −20 °C to 80 °C is obtained at 1.35-V power supply, and a PSNA of 75.7 dB is achieved without any filtering capacitor while dissipating a maximum supply current of 880 nA. The active area is .
Autors: Zhou, Ze-kun;Shi, Y.;Gou, C.;Wang, X.;Wu, G.;Feng, Jie-fei;Wang, Z.;Zhang, B.;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Jul 2016, volume: 63, issue:7, pages: 613 - 617
Publisher: IEEE
 
» A Resource-Efficient Hardware Architecture for Connected Component Analysis
Abstract:
A resource-efficient hardware architecture for connected component analysis (CCA) of streamed video data is presented, which reduces the required hardware resources, especially for larger image widths. On-chip memory requirements increase with image width and dominate the resources of state-of-the-art CCA single-pass hardware architectures. A reduction in on-chip memory resources is essential to meet the ever increasing image sizes of high-definition (HD) and ultra-HD standards. The proposed architecture is resource efficient due to several innovations. An improved label recycling scheme detects the last pixel of an image object in the video stream only a few clock cycles after its occurrence, allowing the reuse of a label in the following image row. The coordinated application of these techniques leads to significant memory savings of more than two orders in magnitude compared with classical two-pass connected component labeling architectures. Compared with the most memory-efficient state-of-the-art single-pass CCA hardware architecture, 42% or more of on-chip memory resources are saved depending on the features extracted. Based on these savings, it is possible to realize an architecture processing video streams of larger images sizes, or to use a smaller and more energy-efficient field-programmable gate array device, or to increase the functionality of already existing image processing pipelines in reconfigurable computing and embedded systems.
Autors: Klaiber, M.J.;Bailey, D.G.;Baroud, Y.O.;Simon, S.;
Appeared in: IEEE Transactions on Circuits and Systems for Video Technology
Publication date: Jul 2016, volume: 26, issue:7, pages: 1334 - 1349
Publisher: IEEE
 
» A Scalable, Non-Parametric Method for Detecting Performance Anomaly in Large Scale Computing
Abstract:
As computer systems continue to grow in scale and complexity, performance problems become common and a major concern for large-scale computing. Performance anomalies caused by application bugs, hardware or software faults, or resource contention can have great impact on system-wide performance and could lead to significant economic losses for service providers. While many detection methods have been presented in the past, the newly emerging challenges are detection scalability and practical use. In this paper, we propose a scalable, non-parametric method for effectively detecting performance anomalies in large-scale systems. The design is generic for anomaly detection in a variety of parallel and distributed systems exhibiting peer-comparable property. It adopts a divide-and-conquer approach to address the scalability challenge and explores the use of non-parametric clustering and two-phase majority voting to improve detection flexibility and accuracy. We derive probabilistic models to quantitatively evaluate our decentralized design. Experiments with a suite of applications on production systems demonstrate that this method outperforms existing methods in terms of detection accuracy with a negligible runtime overhead.
Autors: Yu, L.;Lan, Z.;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Jul 2016, volume: 27, issue:7, pages: 1902 - 1914
Publisher: IEEE
 
» A Semiblind Tracking Algorithm for Joint Communication and Ranging With OFDM Signals
Abstract:
Range-based positioning by estimating the time of arrival (ToA) of the line-of-sight (LoS) path using orthogonal frequency-division multiplexing (OFDM) signals has gained remarkable attention. Multipath propagation significantly influences the ToA estimate, resulting in position errors. To mitigate these errors, the multipath channel needs to be accurately estimated, usually with a large number of known pilot symbols. A tradeoff between the data rate and the multipath channel estimation performance must be made for joint communication and positioning applications. This paper proposes a semiblind range tracking algorithm, which allows the reduction of the required number of pilot symbols significantly. For moving receivers, the algorithm needs, only in the beginning, an OFDM symbol with known pilot symbols, which increases the data rate dramatically. Instead of tracking the complex amplitude of individual subcarriers, the proposed algorithm directly tracks the multipath channel parameters, including the complex amplitude, delay, and angle of arrival (AoA) of individual multipath components. The estimated delay of the first arrived path, i.e., its ToA, is used to calculate the range between the transmitter and receiver antennas. Evaluations of the algorithm are provided by simulations in an artificial scenario and using channel sounder measurement data. The results show that the proposed tracking algorithm can effectively track the range between transmitter and receiver and detect the data.
Autors: Wang, W.;Jost, T.;Gentner, C.;Zhang, S.;Dammann, A.;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jul 2016, volume: 65, issue:7, pages: 5237 - 5250
Publisher: IEEE
 
» A Small Axial-Flux Vernier Machine With Ring-Type Magnets for the Auto-Focusing Lens Drive System
Abstract:
A small axial-flux permanent magnet vernier motor (PMVM) is investigated to satisfy the requirements of high drive torque, low speed, low noise, and low-power consumption for application in the camera auto-focusing lens drive. The proposed axial-flux PMVM is constructed with ring-type magnets in the rotor and has strict dimensional constraints due to its location in the lens barrel. The design approach is an alternative motor design method coupled with the analytical method or the finite-element method. The proposed motor’s electromagnetic performance was verified by means of both methods. Finally, a prototype was built and tested, showing an adequate range of speed while also meeting the noise limits, and consuming less than 2 W of power.
Autors: Zhao, F.;Kim, Min-soo;Kwon, Byung-il;Baek, Jong-ho;
Appeared in: IEEE Transactions on Magnetics
Publication date: Jul 2016, volume: 52, issue:7, pages: 1 - 4
Publisher: IEEE
 
» A Stochastic Approach for Resource Allocation with Backhaul and Energy Harvesting Constraints
Abstract:
We propose a novel stochastic radio-resource-allocation strategy that achieves long-term fairness considering backhaul and air-interface capacity limitations. The base station (BS) is powered only with a finite battery that is recharged by an energy harvester. The energy harvesting is also taken into account in the proposed resource-allocation strategy. The constrained scenario is often found in remote rural areas where the backhaul connection is limited, and the BSs are fed with solar panels of reduced size. Our results show that the proposed scheme achieves higher fairness among the users and provides greater worst user rate and sum rate if an average backhaul constraint is considered.
Autors: Rubio, J.;Munoz-Medina, O.;Pascual-Iserte, A.;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jul 2016, volume: 65, issue:7, pages: 5788 - 5797
Publisher: IEEE
 
» A Street-Centric Opportunistic Routing Protocol Based on Link Correlation for Urban VANETs
Abstract:
In urban vehicular ad hoc networks (VANETs), due to the high mobility and uneven distribution of vehicles, how to select an optimal relaying node in an intra-street and how to determine a street selection at the intersection are two challenging issues in designing an efficient routing protocol in complex urban environments. In this paper, we build a link model with a Wiener process to predict the probability of link availability, which considers the stable and unstable vehicle states according to the behavior of vehicles. We introduce a novel concept called the link correlation which represents the influence of different link combinations in network topology to transmit a packet with less network resource consumption and higher goodput. Based on this concept, we design an opportunistic routing metric called the expected transmission cost over a multi-hop path (ETCoP) implemented with our link model as the selection guidance of a relaying node in intra-streets. This metric can also provide assistance for the next street selection at an intersection. Finally, we propose a street-centric opportunistic routing protocol based on ETCoP for VANETs (SRPE). Simulation results show that our proposed SRPE outperforms the conventional protocols in terms of packet delivery ratio, average end-to-end delay, and network yield.
Autors: Zhang, X.;Cao, X.;Yan, L.;Sung, D.K.;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: Jul 2016, volume: 15, issue:7, pages: 1586 - 1599
Publisher: IEEE
 
» A Street-Centric Routing Protocol Based on Microtopology in Vehicular Ad Hoc Networks
Abstract:
In a vehicular ad hoc network (VANET), high mobility and uneven distribution of vehicles are important factors affecting the performance of routing protocols. The high mobility may cause frequent changes of network topology, whereas the uneven distribution of vehicles may lead to routing failures due to network partition; even high density of vehicles may cause severe wireless channel contentions in an urban environment. In this paper, we propose a novel concept called the microtopology (MT), which consists of vehicles and wireless links among vehicles along a street as a basic component of routing paths and even the entire network topology. We abstract the MT model reflecting the dynamic routing-related characteristics in practical urban scenarios along streets, including the effect of mobility of vehicles, signal fading, wireless channel contention, and existing data traffic. We first analyze the endside-to-endside routing performance in an MT as a basis of routing decision. Then, we propose a novel street-centric routing protocol based on MT (SRPMT) along the streets for VANETs. Simulation results show that our proposed SRPMT protocol achieves higher data delivery rate and shorter average end-to-end delay compared with the performance of greedy perimeter stateless routing (GPSR) and greedy traffic-aware routing (GyTAR).
Autors: Zhang, X.;Chen, K.;Cao, X.;Sung, D.K.;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jul 2016, volume: 65, issue:7, pages: 5680 - 5694
Publisher: IEEE
 
» A Structural Transmission Cost Allocation Scheme Based on Capacity Usage Identification
Abstract:
In liberalized electricity markets, it is essential and of great importance to develop a fair transmission cost allocation scheme that is able to reflect the “extent of use” of the transmission facilities as much as possible. In this paper, the transmission capacity is divided into four components: capacity used in normal conditions (CN), capacity reserved for contingencies (CC), capacity reserved for future use (CF) and invalid capacity (IC). CN and CC are determined by the power flow in the normal and contingency conditions of the system operation snapshot, respectively. The CF is determined by the maximum power flow in contingency conditions over a certain period (say yearly). The cost corresponding to IC would not be allocated to network users. Based on capacity usage identification, differential cost allocation methods are designed according to the functions of the transmission capacity. The cost corresponding to the capacity usage of the transmission asset under normal and contingency conditions is allocated separately. Case studies in a 3-bus system and the IEEE 30-bus system validate the good performance of the proposed structural transmission cost allocation scheme.
Autors: Yang, Z.;Zhong, H.;Xia, Q.;Kang, C.;Chen, T.;Li, Y.;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jul 2016, volume: 31, issue:4, pages: 2876 - 2884
Publisher: IEEE
 
» A Study of the Influence of Quasi-Halbach Arrays on a Torus Machine
Abstract:
This paper aims to analyze the influence of quasi-Halbach arrays on the performance of an axial-flux machine with slotless toroidal core (Torus machine). The analysis was performed using a 3-D finite-element simulation of two machines, with one machine equipped with a quasi-Halbach array and a second with a conventional design with axially magnetized permanent magnets. These simulations were carried out in order to compare their performance. It was observed that the employment of quasi-Halbach arrays increases the torque density and the effective no-load terminal voltage.
Autors: Wiltuschnig, I.;Eckert, P.;Dorrell, D.;Flores Filho, A.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Jul 2016, volume: 52, issue:7, pages: 1 - 4
Publisher: IEEE
 
» A Study on Pulse-Width-Modulation-Based Power Amplification for Underwater Acoustic OFDM
Abstract:
In this paper, we investigate the power amplification for underwater acoustic orthogonal frequency-division multiplexing (OFDM) systems. The maximum power delivery (MPD) and the pilot signal-to-noise ratio (PSNR) specific to the OFDM modulation are adopted as design criteria. We study the impact of key parameters associated with the pulse-width modulation (PWM), such as the modulation frequency, the number of quantization bits, and the input clipping threshold, and provide a suitable procedure to determine those parameters to increase the MPD while meeting a certain PSNR constraint. Experimental setup has been established, where the experimental results validate the key findings from the analytical and simulation results.
Autors: Zhou, H.;Xu, X.;Wei, L.;Zhou, S.;Cui, J.-H.;
Appeared in: IEEE Journal of Oceanic Engineering
Publication date: Jul 2016, volume: 41, issue:3, pages: 656 - 669
Publisher: IEEE
 
» A Study on the Traffic Predictive Cruise Control Strategy With Downstream Traffic Information
Abstract:
A vehicle traffic predictive cruise control (TPCC) system, responding to the change of downstream traffic situation, has been proposed to improve traffic operation and the fuel efficiency of vehicle based on the asymmetric traffic theory. The proposed predictive cruise control system consists of four parts: 1) deceleration-based safety surrogate measure (DSSM); 2) single-vehicle control algorithm; 3) multivehicle safety measurement (Co-DSSM); and 4) TPCC. The single-vehicle control algorithm basically decides the acceleration action based on estimated safety state between a subject vehicle and the immediate preceding vehicle, and the control strategy is determined by asymmetric driving behavior. Then, TPCC adjusts the amount of acceleration based on the Co-DSSM from multiple downstream vehicles, which contains the information on future traffic condition of the subject vehicle. A simulation using the real vehicle trajectories from the Next Generation Simulation (NGSIM) data validates the proposed TPCC system, and we compare the results with the real vehicles' car-following patterns. It is found that the proposed TPCC system can contribute to both the energy consumption and traffic flow operation by obtaining a higher level of traffic stability. Such results are due to the effects of suppressing the shockwave from downstream traffic and removing the unnecessary deceleration and acceleration actions.
Autors: Tak, S.;Kim, S.;Yeo, H.;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: Jul 2016, volume: 17, issue:7, pages: 1932 - 1943
Publisher: IEEE
 
» A Successive Linear ProgrammingPub _newline Approach to Solving the IV-ACOPF
Abstract:
Improved formulations of and solution techniques for the alternating current optimal power flow (ACOPF) problem are critical to improving current market practices in economic dispatch. We introduce the IV-ACOPF formulation that unlike canonical ACOPF formulations-which represent network balancing through nonlinear coupling-is based on a current injections approach that linearly couple the quadratic constraints at each bus; yet, the IV-ACOPF is mathematically equivalent to the canonical ACOPF formulation. We propose a successive linear programming (SLP) approach to solve the IV-ACOPF, which we refer to as the SLP IV-ACOPF algorithm. The SLP IV-ACOPF leverages commercial LP solvers and can be readily extended and integrated into more complex decision processes, e.g., unit commitment and transmission switching. We demonstrate with the standard MATPOWER test suite an acceptable quality of convergence to a best-known solution and linear scaling of computational time in proportion to network size.
Autors: Castillo, A.;Lipka, P.;Watson, J.-P.;Oren, S.S.;O'Neill, R.P.;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jul 2016, volume: 31, issue:4, pages: 2752 - 2763
Publisher: IEEE
 
» A SVM Surrogate Model-Based Method for Parametric Yield Optimization
Abstract:
Yield optimization is a challenging topic in electronic circuit design. Methods for yield optimization based on Monte Carlo (MC) analysis of a circuit whose behavior is reproduced by simulations usually require too many time expensive simulations to be effective for iterative optimization. In this paper, we propose a method which tackles the yield optimization problem by combining a support vector machine (SVM) surrogate model (SM) of the circuit to perform the MC analysis and evaluate the yield, and an efficient optimization method to maximize the yield evaluated using the SVM SM. We report the numerical results obtained for the design of two real consumer circuits provided by STMicroelectronics, and we compare these results with the ones obtained using the industrial benchmark currently adopted at STMicroelectronics for yield optimization. These preliminary results show that the method is promising to be very efficient and capable of reaching design solutions with high values of the yield.
Autors: Latorre, V.;Ciccazzo, A.;Di Pillo, G.;
Appeared in: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Publication date: Jul 2016, volume: 35, issue:7, pages: 1224 - 1228
Publisher: IEEE
 
» A Traffic Adaptive Multi-Channel MAC Protocol with Dynamic Slot Allocation for WSNs
Abstract:
Using low duty-cycle is the most common technique to extend the system lifetime in WSNs. However, it also implies limited throughput and long delay and the penalty is even higher under variable traffic patterns. In this paper, we present iQueue-MAC, a hybrid CSMA/TDMA MAC that adapts to variable/bursty traffic. With light load, iQueue-MAC uses a contention-based CSMA mechanism that provides low delay with scattered transmissions. When traffic increases, detected by a forming backlog in the sender, iQueue-MAC changes to a contention-free TDMA mechanism allocating transmission slots. Thus, iQueue-MAC mitigates packet buffering and reduces packet delay, combining the best of TDMA and CSMA. In this paper we also show how iQueue-MAC can operate in both single and multi channel modes. We implemented it on SIM32W108 chips together with other reference WSN protocols for comparison. iQueue-MAC exhibits similar figures during light traffic. However, with bursty traffic its throughput can be five times that of CoSenS and Ri-MAC-MC and its delay 20 times lower. Finally, iQueue-MAC is able to effectively use multiple channels, duplicating its throughput when compared to single channel operation.
Autors: Zhuo, S.;Wang, Z.;Song, Y.;Wang, Z.;Almeida, L.;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: Jul 2016, volume: 15, issue:7, pages: 1600 - 1613
Publisher: IEEE
 
» A Two-Layer Active Disturbance Rejection Controller Design for Load Frequency Control of Interconnected Power System
Abstract:
This letter proposes a two-layer active disturbance rejection control (ADRC) method with the compensation of estimated equivalent input disturbances (EID) for load frequency control (LFC) of multi-area interconnected power system. This method has a capability of rejecting the effects of random load variations and parameter uncertainties, and guaranteeing high dynamic performance. The state-space model of LFC system is established. Then a full-order generalized state observer (GSO) is employed in ADRC system to estimate EID. A stability condition is derived based on the small-gain theory. Simulation results demonstrate the robust performance of the proposed method, by comparing with traditional one.
Autors: Liu, F.;Li, Y.;Cao, Y.;She, J.;Wu, M.;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jul 2016, volume: 31, issue:4, pages: 3320 - 3321
Publisher: IEEE
 
» A Two-Stage Large-Capacitive-Load Amplifier With Multiple Cross-Coupled Small-Gain Stages
Abstract:
A two-stage large-capacitive-load amplifier with multiple cross-coupled small-gain stages is proposed in this paper. The cross-coupled structure of the small-gain stages augments the large-signal responses, providing significant improvement in the effective output-stage transconductance and, hence, the gain–bandwidth product (GBW). Implemented in a standard 0.13- CMOS technology and powered by a 0.7 V supply with a current consumption of , the proposed amplifier achieves the GBW of 1.17 MHz and the phase margin of 74.8° while driving a capacitive load of 9.5 nF. The average slew rate is 0.3679 V/. The on-chip compensation capacitor is only 1.62 pF. The active chip area is 0.0056 mm2.
Autors: Ho, M.;Guo, J.;Mui, T.W.;Mak, K.H.;Goh, W.L.;Poon, H.C.;Bu, S.;Lau, M.W.;Leung, K.N.;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Jul 2016, volume: 24, issue:7, pages: 2580 - 2592
Publisher: IEEE
 
» Achieving Economic Operation and Secondary Frequency Regulation Simultaneously Through Feedback Control
Abstract:
This letter presents an important finding: the parameters of secondary frequency control based on integral or proportional integral control can be tuned to achieve economic operation and frequency regulation simultaneously. We show that if the power imbalance is represented by frequency deviation, an iterative dual ascent based economic dispatch solving is equivalent to integral control. An iterative method of multipliers based economic dispatch is equivalent to proportional integral control. Similarly, if the controller parameters of the secondary frequency controls are chosen based on generator cost functions, these secondary frequency controllers achieve both economic operation and frequency regulation simultaneously.
Autors: Miao, Z.;Fan, L.;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jul 2016, volume: 31, issue:4, pages: 3324 - 3325
Publisher: IEEE
 
» Adaptive Robust Tie-Line Scheduling Considering Wind Power Uncertainty for Interconnected Power Systems
Abstract:
Large-scale wind farms are typically geographically separated from load centers and distributed in different control areas. Therefore, interregional energy dispatch is important for wind power generation via sharing spinning reserve capacity among interconnected systems. However, existing tie-line scheduling methods in China do not provide satisfactory performance in accommodating the recent large-scale integration of wind power. In this paper, we describe a coordination framework for tie-line scheduling and power dispatch to operate multi-area systems. Tie-line flows are updated hourly to hedge uncertainty in the near future, preserving the operational independence of areas. The coordinated tie-line scheduling problem is formulated using two-stage adaptive robust optimization to account for uncertainties in the available wind power and is solved using a column-and-constraint generation method in a coordinate-and-decentralize manner. Comparative simulations show that the method is effective in enabling further wind power penetration and can improve economic efficiency in multi-area systems. A case study using a large-scale power system demonstrates the benefits and scalability of the method in practice.
Autors: Li, Z.;Wu, W.;Shahidehpour, M.;Zhang, B.;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jul 2016, volume: 31, issue:4, pages: 2701 - 2713
Publisher: IEEE
 
» Admission Control Scheme for Service Dropping Performance Improvement in High-Speed Railway Communication Systems
Abstract:
In high-speed railway communication (HSRC) systems, ensuring the continuity of on-going services is one of the toughest challenges for the existence of influential factors such as frequent handoff event, short time window for handoff, severe channel distortion, etc. In HSRC systems with limited resources, admission control (AC) is one of the most efficient methods to overcome this challenge and guarantee the requirement of service dropping probability (SDP). However, now, there is still a lack of a recognized AC scheme that can be used in HSRC systems. In this paper, a novel AC scheme is proposed to HSRC systems, where the resource reservation algorithm and resource preemption model are developed together to reduce the SDP. First, the main reasons for on-going service dropping related to the AC scheme are analyzed, which include frequent adjustment of services' modulation-and-coding scheme (MCS) and continual handoff events. Second, an adaptive resource reservation algorithm is proposed to optimize the amount of reserved bandwidth for on-going services, where the effect of MCS change at the physical layer, and the characteristics of HSRC are both taken into account. Third, considering the effect of resource preemption on on-going services, a resource preemption model is developed to further obtain the available bandwidth resources. Then, according to the above works, the AC scheme is proposed to optimize the SDP performance. Finally, simulation results are presented to demonstrate the effectiveness of the proposed AC scheme.
Autors: Xu, Q.;Ji, H.;Li, X.;Zhang, H.;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jul 2016, volume: 65, issue:7, pages: 5251 - 5263
Publisher: IEEE
 
» An Access Control Model for Online Social Networks Using User-to-User Relationships
Abstract:
Users and resources in online social networks (OSNs) are interconnected via various types of relationships. In particular, user-to-user relationships form the basis of the OSN structure, and play a significant role in specifying and enforcing access control. Individual users and the OSN provider should be enabled to specify which access can be granted in terms of existing relationships. In this paper, we propose a novel user-to-user relationship-based access control (UURAC) model for OSN systems that utilizes regular expression notation for such policy specification. Access control policies on users and resources are composed in terms of requested action, multiple relationship types, the starting point of the evaluation, and the number of hops on the path. We present two path checking algorithms to determine whether the required relationship path between users for a given access request exists. We validate the feasibility of our approach by implementing a prototype system and evaluating the performance of these two algorithms.
Autors: Cheng, Y.;Park, J.;Sandhu, R.;
Appeared in: IEEE Transactions on Dependable and Secure Computing
Publication date: Jul 2016, volume: 13, issue:4, pages: 424 - 436
Publisher: IEEE
 
» An Accurate GPU Performance Model for Effective Control Flow Divergence Optimization
Abstract:
Graphic processing units (GPUs) are composed of a group of single-instruction multiple data (SIMD) streaming multiprocessors (SMs). GPUs are able to efficiently execute highly data parallel tasks through SIMD execution on the SMs. However, if those threads take diverging control paths, all divergent paths are executed serially. In the worst case, every thread takes a different control path and the highly parallel architecture is used serially by each thread. This control flow divergence problem is well known in GPU development; code transformation, memory access redirection, and data layout reorganization are commonly used to reduce the impact of divergence. These techniques attempt to eliminate divergence by grouping together threads or data to ensure identical behavior. However, prior efforts using these techniques do not model the performance impact of any particular divergence or consider that complete elimination of divergence may not be possible. Thus, we perform analysis of the performance impact of divergence and potential thread regrouping algorithms that eliminate divergence or minimize the impact of remaining divergence. Finally, we develop a divergence optimization framework that analyzes and transforms the kernel at compile-time and regroups the threads at runtime. For the compute-bound applications, our proposed metrics achieve performance estimation accuracy within 6.2% of measured performance. Using these metrics, we develop thread regrouping algorithms, which consider the impact of divergence, and speed up these applications by on average on NVIDIA GTX480.
Autors: Liang, Y.;Satria, M.;Rupnow, K.;Chen, D.;
Appeared in: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Publication date: Jul 2016, volume: 35, issue:7, pages: 1165 - 1178
Publisher: IEEE
 
» An Adaptive Control Strategy for Low Voltage Ride Through Capability Enhancement of Grid-Connected Photovoltaic Power Plants
Abstract:
This paper presents a novel application of continuous mixed p-norm (CMPN) algorithm-based adaptive control strategy with the purpose of enhancing the low voltage ride through (LVRT) capability of grid-connected photovoltaic (PV) power plants. The PV arrays are connected to the point of common coupling (PCC) through a DC-DC boost converter, a DC-link capacitor, a grid-side inverter, and a three-phase step up transformer. The DC-DC converter is used for a maximum power point tracking operation based on the fractional open circuit voltage method. The grid-side inverter is utilized to control the DC-link voltage and terminal voltage at the PCC through a vector control scheme. The CMPN algorithm-based adaptive proportional-integral (PI) controller is used to control the power electronic circuits due to its very fast convergence. The proposed algorithm updates the PI controller gains online without the need to fine tune or optimize. For realistic responses, the PV power plant is connected to the IEEE 39-bus New England test system. The effectiveness of the proposed control strategy is compared with that obtained using Taguchi approach-based an optimal PI controller taking into account subjecting the system to symmetrical, unsymmetrical faults, and unsuccessful reclosing of circuit breakers due to the existence of permanent fault. The validity of adaptive control strategy is extensively verified by the simulation results, which are carried out using PSCAD/EMTDC software. With the proposed adaptive-controlled PV power plants, the LVRT capability of such system can be improved.
Autors: Hasanien, H.M.;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jul 2016, volume: 31, issue:4, pages: 3230 - 3237
Publisher: IEEE
 
» An Aggregate Model of Plug-in Electric Vehicles Including Distribution Network Characteristics for Primary Frequency Control
Abstract:
In the future, the number of plug-in electric vehicles (PEVs) that will participate in the primary frequency control (PFC) is likely to increase. In our previous research, the computational complexity of the PFC problem for a large number of PEVs was reduced using aggregate models of PEVs. However, in the literature on the PFC, the distribution network characteristics have not been included in the aggregate models of PEVs for the PFC, despite the fact that PEVs will be dispersedly connected to the distribution network. This paper proposes an aggregate model of PEVs for the PFC that further incorporates distribution network characteristics, i.e., the distribution network power loss (DNPL) and the maximum allowed current (MAC) of the lines and transformers. The DNPL variation is formulated according to the line and transformer impedance, spatial distribution of PEVs and loads, and active power variation of PEVs. Then, DNPL variation together with the MAC of the lines and transformers are incorporated in the proposed model of PEVs. Finally, the simulation results show an excellent agreement of 98% between the detailed model and the proposed aggregate model of PEVs.
Autors: Izadkhast, S.;Garcia-Gonzalez, P.;Frias, P.;Ramirez-Elizondo, L.;Bauer, P.;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jul 2016, volume: 31, issue:4, pages: 2987 - 2998
Publisher: IEEE
 
» An Assessment of the Impact of Uncertainty on Automatic Generation Control Systems
Abstract:
This paper proposes a framework to quantify the impact of uncertainty that arises from load variations, renewable-based generation, and noise in communication channels on the automatic generation control (AGC) system. To this end, we rely on a model of the power system that includes the synchronous generator dynamics, the network, and the AGC system dynamics, as well as the effect of various sources of uncertainty. Then, we develop a method to analytically propagate the uncertainty from the aforementioned sources to the system frequency and area control error (ACE), and obtain expressions that approximate their probability distribution functions. We make use of this framework to obtain probabilistic expressions for the frequency performance criteria developed by the North American Electric Reliability Corporation (NERC); such expressions may be used to determine the limiting values of uncertainty that the system may withstand. The proposed ideas are illustrated through the Western Electricity Coordination Council (WECC) 9-bus 3-machine system and a 140-bus 48-machine system.
Autors: Apostolopoulou, D.;Dominguez-Garcia, A.D.;Sauer, P.W.;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jul 2016, volume: 31, issue:4, pages: 2657 - 2665
Publisher: IEEE
 
» An Efficient Approach to Short-Term Load Forecasting at the Distribution Level
Abstract:
Short-term load forecasting at the distribution level predicts the load of substations, feeders, transformers, and possibly customers from half an hour to one week ahead. Effective forecasting is important for the planning and operation of distribution systems. The problem, however, is difficult in view of complicated load features, the large number of distribution-level nodes, and possible switching operations. In this paper, a new forecasting approach within the hierarchical structure is presented to solve these difficulties. Load of the root node at any user-defined subtree is first forecast by a wavelet neural network with appropriate inputs. Child nodes categorized as “regular” and “irregular” based on load pattern similarities are then forecast separately. Load of a regular child node is simply forecast as the proportion from the parent node load forecast while the load of an irregular child node is forecast by an individual neural network model. Switching operation detection and follow-up adjustments are also performed to capture abnormal changes and improve the forecasting accuracy. This new approach captures load characteristics of nodes at different levels, takes advantage of pattern similarities between a parent node and its child nodes, detects abnormalities, and provides high quality forecasts as demonstrated by two practical datasets.
Autors: Sun, X.;Luh, P.B.;Cheung, K.W.;Guan, W.;Michel, L.D.;Venkata, S.S.;Miller, M.T.;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jul 2016, volume: 31, issue:4, pages: 2526 - 2537
Publisher: IEEE
 
» An Efficient MILP Approximation for the Hydro-Thermal Unit Commitment
Abstract:
In a hydro-thermal unit commitment (H-TUC) problem, accurate modeling of the hydro unit power generation, which is a nonlinear function of the net head and the total power release, is crucial but difficult due to its nonlinearity and non-concavity. This letter proposes an efficient mixed integer linear program (MILP) approximation method for the H-TUC problem based on the variable separation and piecewise linear (PWL) technique. Tests on different systems demonstrate the proposed method can provide high quality solutions more efficiently.
Autors: Chen, Y.;Liu, F.;Liu, B.;Wei, W.;Mei, S.;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jul 2016, volume: 31, issue:4, pages: 3318 - 3319
Publisher: IEEE
 
» An Energy-Efficient Resource Allocation and Interference Management Scheme in Green Heterogeneous Networks Using Game Theory
Abstract:
In heterogeneous networks (HetNets), energy-efficient resource allocation and intercell-interference management are important issues. In this paper, we address these issues using a two-level dynamic scheme. First, we assign the MUs with the optimum number of subchannels that achieves an operator's required balance between macro users' satisfaction and maximization of network efficiency. Then, the remaining subchannels are left to be shared by a number of small cells. In the latter step, a transmit power adaptation method using a noncooperative game-theoretic approach is developed to reduce cochannel interference in the whole network. The problem is formulated by allowing multiple neighboring small cells to share each subchannel (i.e., universal frequency reuse in the small cell level). We fully characterize the pricing factor in the penalty part of the utility function. The existence and uniqueness of the Nash equilibrium (NE) are analyzed and proved. Then, a distributed iterative algorithm based on the fixed-point theorem is proposed to attain the equilibrium of the game. Simulation results are presented to show the effectiveness of the proposed scheme in different network topologies.
Autors: Al-Zahrani, A.;Yu, F.;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jul 2016, volume: 65, issue:7, pages: 5384 - 5396
Publisher: IEEE
 
» An Improved Method for Armature-Reaction Magnetic Field Calculation of Interior Permanent Magnet Motors
Abstract:
This paper proposes an improved analytical method to calculate the armature-reaction magnetic field (ARMF) of interior permanent magnet motors. Based on the winding function, the armature-reaction magnetic motive force is divided into the -axis component and the -axis component to facilitate the analysis. Considering the flux paths, the difference of rotor magnetic potentials in the -axis and the -axis is illustrated, which improves the accuracy of the ARMF calculation. The validity of the analytical technique is verified by the 2-D finite-element analysis.
Autors: Liang, P.;Pei, Y.;Chai, F.;Bi, Y.;Cheng, S.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Jul 2016, volume: 52, issue:7, pages: 1 - 4
Publisher: IEEE
 
» An Improved Stochastic Unit Commitment Formulation to Accommodate Wind Uncertainty
Abstract:
The United States targets to supply 20% of its electricity generation using wind energy by 2030. The expansion of renewable resources, especially weather-based resources such as wind, creates more uncertainty and variability in the operation of the power grid. New methods and approaches in electricity market operations are needed to efficiently manage the continuing increase in variability and uncertainty caused by expanding intermittent wind. This paper proposes an improved stochastic programming approach for incorporating wind uncertainty into energy markets. The proposed formulation improves the two-stage stochastic unit commitment problem by introducing a dynamic decision making approach similar to a multi-stage formulation in the presence of wind power scenarios which are not well represented by a scenario tree. The numerical results present up to 1%-2% decrease in operational costs compared to the two-stage stochastic unit commitment formulation.
Autors: Uckun, C.;Botterud, A.;Birge, J.R.;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jul 2016, volume: 31, issue:4, pages: 2507 - 2517
Publisher: IEEE
 
» An Incidental Delivery Based Method for Resolving Multirobot Pairwised Transportation Problems
Abstract:
This paper presents a multirobot pairwised transportation (MRPWT) approach for factory automated material and product deliveries. We consider MRPWT from the viewpoint of robotics and incorporate practical factory application constraints in the transportation method design. The proposed MRPWT approach is a two-level hybrid planning method, consisting of an incidental delivery based single robot level planner and a simulated annealing based robot group level planner. Each robot resolves its individual transportation plan incidentally to reduce the transportation cost, whereas the group level planner utilizes predefined random actions to search the task assignment solution space and then incorporates the simulated annealing algorithm to resolve the MRPWT problem as a combinatorial optimization problem. By implementing a distributed auction mechanism, the proposed MRPWT approach can be further extended to resolve the online task allocation or reallocation problem in dynamic environments. Experiments performed on a group of mobile robots successfully demonstrate the effectiveness and the practical applicability of the proposed MRPWT approach for factory automated material and product deliveries.
Autors: Liu, Z.;Wang, H.;Chen, W.;Yu, J.;chen, J.;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: Jul 2016, volume: 17, issue:7, pages: 1852 - 1866
Publisher: IEEE
 
» An Inductively Filtered Multiwinding Rectifier Transformer and Its Application in Industrial DC Power Supply System
Abstract:
In this paper, a new industrial direct-current (dc) power supply system with the four-winding inductively filtered rectifier transformer (FW-IFRT) is proposed based on an inductive filtering (IF) method, which can effectively solve the power quality problems generally existing in the high-power rectifier system, such as high energy consumption, serious harmonic pollution, low power factor, and so on. The single-phase equivalent circuit model of such a new system is established based on the multiwinding transformer theory, and then its operating characteristics are investigated in detail. The harmonic suppression factor is proposed, and the influences of system and transformer impedances on the harmonic suppression characteristic are revealed. Finally, the simulation and experimental case studies are used to verify the effectiveness of the proposed system on the comprehensive improvement of power quality and operating efficiency.
Autors: Li, Y.;Yao, F.;Liu, F.;Luo, L.;Chen, Y.;Cao, Y.;Christian, R.;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Jul 2016, volume: 63, issue:7, pages: 3987 - 3997
Publisher: IEEE
 
» An Inflatable and Wearable Wireless System for Making 32-Channel Electroencephalogram Measurements
Abstract:
Potable electroencephalography (EEG) devices have become critical for important research. They have various applications, such as in brain–computer interfaces (BCI). Numerous recent investigations have focused on the development of dry sensors, but few concern the simultaneous attachment of high-density dry sensors to different regions of the scalp to receive qualified EEG signals from hairy sites. An inflatable and wearable wireless 32-channel EEG device was designed, prototyped, and experimentally validated for making EEG signal measurements; it incorporates spring-loaded dry sensors and a novel gasbag design to solve the problem of interference by hair. The cap is ventilated and incorporates a circuit board and battery with a high-tolerance wireless (Bluetooth) protocol and low power consumption characteristics. The proposed system provides a 500/250 Hz sampling rate, and 24 bit EEG data to meet the BCI system data requirement. Experimental results prove that the proposed EEG system is effective in measuring audio event-related potential, measuring visual event-related potential, and rapid serial visual presentation. Results of this work demonstrate that the proposed EEG cap system performs well in making EEG measurements and is feasible for practical applications.
Autors: Yu, Yi-Hsin;Lu, Shao-Wei;Chuang, Chun-Hsiang;King, Jung-Tai;Chang, Che-Lun;Chen, S.;Chen, Sheng-Fu;Lin, Chin-Teng;
Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Publication date: Jul 2016, volume: 24, issue:7, pages: 806 - 813
Publisher: IEEE
 
» An Integral-Type Multiple Lyapunov Functions Approach for Switched Nonlinear Systems
Abstract:
An integral-type multiple Lyapunov functions (MLFs) approach for switched nonlinear systems is set up for the first time, which gives a more general condition for analyzing the behavior of switched nonlinear systems since the Branicky's nonincreasing condition is no longer assumed and the generalized MLFs condition is a special case of the condition provided. Meanwhile, based on the integral-type MLFs approach, global stabilization for a class of switched nonlinear systems in - normal form is achieved by constructing state-feedback controllers of subsystems and a proper switching law, where the solvability of the problem under study for individual subsystems is not assumed. Two examples are also provided to demonstrate the effectiveness of the proposed design method.
Autors: Long, L.;Zhao, J.;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Jul 2016, volume: 61, issue:7, pages: 1979 - 1986
Publisher: IEEE
 
» An Integrated Approach for Managing Read Disturbs in High-Density NAND Flash Memory
Abstract:
The read-disturb problem is emerging as one of the main reliability issues in high-density NAND flash memory. A read-disturb error, which causes data loss, occurs to a page when a large number of reads are performed to its neighboring pages. In this paper, we propose a novel integrated approach for managing the read-disturb problem. Our approach is based on our key observations from the NAND physics that the read disturbance to neighboring pages is a function of the read voltage and the read time. Since the read disturbance has an exponential dependence on the read voltage, lowering the read voltage can improve the read-disturb resistance of a NAND block. By modifying NAND chips to support multiple read modes with different read voltages, our approach allows a flash translation layer module to exploit the tradeoff between the read disturbance and write speed. Since the read disturbance is also proportional to the read time, our approach exploits the difference in the read time among different NAND pages so that frequently read pages can be less intensively read-disturbed using fast page reads. By intelligently relocating read-intensive data to read-disturb resistant blocks and pages, our approach can reduce a large portion of the time overhead from managing read-disturb errors. We also propose a proactive data migration technique which is effective in reducing large variations in I/O response times of the existing on-demand read reclaim (RR) technique. Our experimental results show that our proposed techniques can reduce the execution time overhead by 73% over the existing read-disturb management technique while reducing I/O response time fluctuations during RR activations.
Autors: Ha, K.;Jeong, J.;Kim, J.;
Appeared in: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Publication date: Jul 2016, volume: 35, issue:7, pages: 1079 - 1091
Publisher: IEEE
 
» An Obstructive Sleep Apnea Detection Approach Using a Discriminative Hidden Markov Model From ECG Signals
Abstract:
Obstructive sleep apnea (OSA) syndrome is a common sleep disorder suffered by an increasing number of people worldwide. As an alternative to polysomnography (PSG) for OSA diagnosis, the automatic OSA detection methods used in the current practice mainly concentrate on feature extraction and classifier selection based on collected physiological signals. However, one common limitation in these methods is that the temporal dependence of signals are usually ignored, which may result in critical information loss for OSA diagnosis. In this study, we propose a novel OSA detection approach based on ECG signals by considering temporal dependence within segmented signals. A discriminative hidden Markov model (HMM) and corresponding parameter estimation algorithms are provided. In addition, subject-specific transition probabilities within the model are employed to characterize the subject-to-subject differences of potential OSA patients. To validate our approach, 70 recordings obtained from the Physionet Apnea-ECG database were used. Accuracies of 97.1% for per-recording classification and 86.2% for per-segment OSA detection with satisfactory sensitivity and specificity were achieved. Compared with other existing methods that simply ignore the temporal dependence of signals, the proposed HMM-based detection approach delivers more satisfactory detection performance and could be extended to other disease diagnosis applications.
Autors: Song, C.;Liu, K.;Zhang, X.;Chen, L.;Xian, X.;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Jul 2016, volume: 63, issue:7, pages: 1532 - 1542
Publisher: IEEE
 

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