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Electrical and Electronics Engineering publications abstract of: 08-2010 sorted by title, page: 18
» Of Electrical Distribution Systems With Multiple Grounded Neutrals
Abstract:
Multiple grounded neutral systems require that, on most land-based ac current service installations, the bonding conductor used to connect the non-current-carrying metal parts of equipment, the system grounded conductor (neutral), and the grounding electrodes be bonded together at the service entrance box. Users thus share their ground with the serving utility's neutral ground. This interconnection, although functional, poses some distinctive problems to utility companies as well as to users, which this paper seeks to clarify.
Autors: Mitolo, M.;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Aug 2010, volume: 46, issue:4, pages: 1541 - 1546
Publisher: IEEE
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» Off-Axis Photoacoustic Microscopy
Abstract:
Photoacoustic microscopy (PAM) is a high-contrast, high-resolution imaging modality, used primarily for imaging hemoglobin and melanin. Important applications include mapping of the microvasculature and melanoma tumor margins. We demonstrate a novel PAM design that markedly simplifies the implementation by separating the optical illumination from the acoustic detection path. This modification enables the use of high-quality commercial optics and transducers, and may be readily adapted to commercial light microscopes. The designed PAM system is only sensitive to signals generated in the overlap of the illumination and detection solid angles, providing the additional benefit of quasi-dark-field detection. An off-axis PAM system with a lateral resolution of 26 m and a modest axial resolution of 410 m has been assembled and characterized using tissue samples. The axial resolution is readily scaled down to tens of micrometers within the same design, by utilizing commercially available high-frequency acoustic transducers.
Autors: Shelton, R. L.;Applegate, B. E.;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Aug 2010, volume: 57, issue:8, pages: 1835 - 1838
Publisher: IEEE
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» OI and fMRI Signal Separation Using Both Temporal and Spatial Autocorrelations
Abstract:
Separating brain imaging signals by maximizing their autocorrelations is an important component of blind source separation (BSS). Canonical correlation analysis (CCA), one of leading BSS techniques, has been widely used for analyzing optical imaging (OI) and functional magnetic resonance imaging (fMRI) data. However, because of the need to reduce dimensionality and ignore spatial autocorrelation, CCA is problematic for separating temporal signal sources. To solve the problems of CCA, “straightforward image projection” (SIP) has been incorporated into temporal BSS. This novel method, termed low-dimensional canonical correlation analysis (LD-CCA), relies on the spatial and temporal autocorrelations of all genuine signals of interest. Incorporating both spatial and temporal information, here we introduce a “generalized timecourse” technique in which data are artificially reorganized prior to separation. The quantity of spatial plus temporal autocorrelations can then be defined. By maximizing temporal and spatial autocorrelations in combination, LD-CCA is able to obtain expected “real” signal sources. Generalized timecourses are low-dimensional, eliminating the need for dimension reduction. This removes the risk of discarding useful information. The new method is compared with temporal CCA and temporal independent component analysis (tICA). Comparison of simulated data showed that LD-CCA was more effective for recovering signal sources. Comparisons using real intrinsic OI and fMRI data also supported the validity of LD-CCA.
Autors: Li, M.;Liu, Y.;Feng, G.;Zhou, Z.;Hu, D.;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Aug 2010, volume: 57, issue:8, pages: 1917 - 1926
Publisher: IEEE
Full litterature document
 
» On Almost Sure Stability of Hybrid Stochastic Systems With Mode-Dependent Interval Delays
Abstract:
This note develops a criterion for almost sure stability of hybrid stochastic systems with mode-dependent interval time delays, which improves an existing result by exploiting the relation between the bounds of the time delays and the generator of the continuous-time Markov chain. The improved result shows that the presence of Markovian switching is quite involved in the stability analysis of delay systems. Numerical examples are given to verify the effectiveness.
Autors: Huang, L.;Mao, X.;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Aug 2010, volume: 55, issue:8, pages: 1946 - 1952
Publisher: IEEE
Full litterature document
 
» On an Efficient NoC Multicasting Scheme in Support of Multiple Applications Running on Irregular Sub-Networks
Abstract:
When a number of applications simultaneously running on a many-core chip multiprocessor (CMP) chip connected through network-on-chip (NoC), significant amount of on-chip traffic is one-to-many (multicast) in nature. As a matter of fact, when multiple applications are mapped onto an NoC architecture with applicable traffic isolation constraints, the corresponding sub-networks of these applications are mapped onto actually tend to be irregular. In the literature, multicasting for irregular topologies is supported through either multiple unicasting or broadcasting, which, unfortunately, results in overly high power consumption and/or long network latency. To address this problem, a simple, yet efficient hardware-based multicasting scheme is...
Autors: Xiaohang, Wang , Mei, Yang , Yingtao, Jiang , Peng, Liu
Appeared in: Microprocessors and Microsystems
Publication date: Aug 2010
Publisher: Elsevier B.V.
Full litterature document
 
» On Angle Feedback and Antenna Shuffling in Double Space-Time Transmit Diversity Systems
Abstract:
In this letter, we compare angle feedback and transmit antenna shuffling schemes for double space-time transmit diversity (DSTTD) systems with four transmit antennas and at least two receive antennas. We show that a DSTTD system with one bit of angle feedback does not provide better performance than the same system with one bit of transmit antenna shuffling. We also present a simplified general result about the selection of antenna shuffling matrix from six permutation matrices to facilitate our arguments. In simulation, we observe that antenna shuffling outperforms angle feedback in i.i.d. Rayleigh fading channels.
Autors: Xu, Tao;Liu, Huaping;
Appeared in: IEEE Communications Letters
Publication date: Aug 2010, volume: 14, issue:8, pages: 701 - 703
Publisher: IEEE
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» On compressible Korteweg fluid-like materials?
Abstract:
We provide a thermodynamic basis for compressible fluids of a Korteweg type that are characterized by the presence of the dyadic product of the density gradients ????? in the constitutive equation for the Cauchy stress. Our approach does not need to introduce any new or non-standard concepts such as multipolarity or interstitial working and is based on prescribing the constitutive equations for two scalars: the entropy and the entropy production. In comparison with the Navier-Stokes-Fourier fluids we suppose that the entropy is not only a function of the internal energy and the density but also of the density gradient. The...
Autors: Martin, Heida , Josef, Málek
Appeared in: International Journal of Engineering Science
Publication date: Aug 2010
Publisher: Elsevier B.V.
Full litterature document
 
» On Energy Efficient Encryption for Video Streaming in Wireless Sensor Networks
Abstract:
Selective encryption for video streaming was proposed for efficient multimedia content protection. However, the issues on joint optimization of video quality, content protection, and communication energy efficiency in a wireless sensor network (WSN) have not been fully addressed in the literature. In this paper, we propose a scheme to optimize the energy, distortion, and encryption performance of video streaming in WSNs. The contribution of this work is twofold. First, a channel-aware selective encryption approach is proposed to minimize the extra encryption dependency overhead at the application layer. Second, an unequal error protection (UEP)-based network resource allocation scheme is proposed to improve the communication efficiency at the lower layers. Simulation experiments demonstrate that the proposed joint selective encryption and resource allocation scheme can improve the video transmission quality significantly with guaranteed content protection and energy efficiency.
Autors: Wang, W.;Hempel, M.;Peng, D.;Wang, H.;Sharif, H.;Chen, H.-H.;
Appeared in: IEEE Transactions on Multimedia
Publication date: Aug 2010, volume: 12, issue:5, pages: 417 - 426
Publisher: IEEE
Full litterature document
 
» On equivalence between internal and external model-based repetitive learning controllers for nonlinear passive systems
Abstract:
In this paper a new class of globally stable finite dimensional repetitive controllers for nonlinear passive systems is proposed. The proposed internal model-based repetitive controller has a structure in the form of a parallel connection of linear oscillators and one integrator. The passive interconnection of the controller and the nonlinear passive systems provides the same stability conditions as the controller with the exact feed-forward compensation of system dynamics. The existing internal and external model-based repetitive controllers can be derived as the special cases of the proposed controller.Copyright © 2010 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
Autors: J. Kasac, B. Novakovic, V. Milic
Appeared in: Asian Journal of Control
Publication date: Aug 2010
Publisher: Wiley InterScience
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» On Gaussian Optimal Smoothing of Non-Linear State Space Models
Abstract:
In this note we shall present a new Gaussian approximation based framework for approximate optimal smoothing of non-linear stochastic state space models. The approximation framework can be used for efficiently solving non-linear fixed-interval, fixed-point and fixed-lag optimal smoothing problems. We shall also numerically compare accuracies of approximations, which are based on Taylor series expansion, unscented transformation, central differences and Gauss-Hermite quadrature.
Autors: Sarkka, S.;Hartikainen, J.;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Aug 2010, volume: 55, issue:8, pages: 1938 - 1941
Publisher: IEEE
Full litterature document
 
» On guaranteed VoD services in next generation optical access networks
Abstract:
Video on demand (VoD) is one of the most important services for many network operators that deploy and operate optical access networks. It is crucial to design next generation optical access networks that can guarantee a high quality VoD service. In this paper, we address this challenging issue and focus on the worst-case playback delay (WPD), which cannot be guaranteed by Internet-based video streaming, and has not been well addressed previously in optical access networks. Specifically, we first propose an integrated Gigabit Passive Optical Network (GPON) and Wavelength Division Multiplexing PON (WDM PON) architecture. With the proposed architecture, an optical line terminal (OLT) can broadcast popular videos through GPON and deliver other videos through WDM-PON, while the optical network units (ONUs) can conduct patching for their end users. We then elaborate on two minimum-WPD schemes. In the first one, we assume that the video broadcast schedule is fixed at the OLT and develop an optimal patching scheme at each ONU such that the WPD is minimized. In the second one, we consider coordinated OLT broadcast scheduling and ONU patching. A heuristic algorithm which can achieve near-optimal WPD is proposed for coordinated OLT broadcast scheduling and ONU patching. Simulation results confirm the superiority of the proposed schemes over the existing ones in terms of both worstcase and average delay performance.
Autors: Wang, J.;Qiao, C.;Li, Y.;Lu, K.;
Appeared in: IEEE Journal on Selected Areas in Communications
Publication date: Aug 2010, volume: 28, issue:6, pages: 875 - 888
Publisher: IEEE
Full litterature document
 
» On Integer Values of Kloosterman Sums
Abstract:
This paper considers rational integer values of Kloosterman sums over finite fields of characteristic . We shall prove two main results. The first one is a congruence relation satisfied by possible integer values. One consequence is that there are no Kloosterman zeroes in the case of characteristic , which generalizes recent works by Shparlinski, Moisio, and Lisoněk on this subject. This, in turn, implies that there are no Dillon type bent functions in the case , thus answering a question posed recently by Helleseth and Kholosha. Our other main result states that the Kloosterman sum obtains an integer value at a point if and only if the same sum lifted to any extension field remains an integer.
Autors: Kononen, K. P.;Rinta-aho, M. J.;Vaananen, K. O.;
Appeared in: IEEE Transactions on Information Theory
Publication date: Aug 2010, volume: 56, issue:8, pages: 4011 - 4013
Publisher: IEEE
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» On Maximizing Reliability of Real-Time Embedded Applications Under Hard Energy Constraint
Abstract:
The dynamic voltage and frequency scaling (DVFS) technique is the basis of numerous state-of-the-art energy management schemes proposed for real-time embedded systems. However, recent research has illustrated the alarmingly negative impact of DVFS on task and system reliability. In this paper, we consider the problem of assigning processing frequencies to a set of real-time tasks in order to maximize the overall reliability, under given time and energy constraints. First, under the frame-based task model, we formulate the problem as a nonlinear optimization problem and show how to obtain the static optimal solution. Then, we propose online (dynamic) algorithms that detect early completions and adjust the task frequencies at runtime, to improve overall reliability. Furthermore, we extend these solutions to the periodic task model, with both static and dynamic solutions. All our solutions ensure that all timing constraints are met while the cumulative energy consumption of tasks does not exceed the given energy budget. Our simulation results indicate that our algorithms perform comparably to a clairvoyant optimal scheduler that knows the exact workload in advance.
Autors: Zhao, B.;Aydin, H.;Zhu, D.;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Aug 2010, volume: 6, issue:3, pages: 316 - 328
Publisher: IEEE
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» On Rate of Convergence of Statistical Estimation of Stationary Ergodic Processes
Abstract:
Stationary ergodic processes with finite alphabets are approximated by finite memory processes based on an -length realization of the process. Under the assumptions of summable continuity rate and non-nullness, a rate of convergence in -distance is obtained, with explicit constants. Asymptotically, as , the result is near the optimum.
Autors: Csiszar, I.;Talata, Z.;
Appeared in: IEEE Transactions on Information Theory
Publication date: Aug 2010, volume: 56, issue:8, pages: 3637 - 3641
Publisher: IEEE
Full litterature document
 
» On Reducing Test Power and Test Volume by Selective Pattern Compression Schemes
Abstract:
In modern chip designs, test strategies are becoming one of the most important issues due to the increase of the test cost, among them we focus on the large test power dissipation and large test data volume. In this paper, we develop a methodology to suppress the test power to avoid chip failures caused by large test power, and our methodology is also effective in reducing the test data volume and shift-in power. The proposed schemes and techniques are based on the selective test pattern compression, they can reduce considerable shift-in power by skipping the switching signal passing through long scan chains. The experimental results with ISCAS89 circuits demonstrate that our methodology can achieve significant improvement in the reduction of shift-in power and test data volume. Our approach also supports multiple scan chains.
Autors: Lin, C.-Y.;Lin, H.-C.;Chen, H.-M.;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Aug 2010, volume: 18, issue:8, pages: 1220 - 1224
Publisher: IEEE
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» On Some Necessary and Sufficient Conditions for a Recurrent Neural Network Model With Time Delays to Generate Oscillations
Abstract:
In this paper, the existence of oscillations for a class of recurrent neural networks with time delays between neural interconnections is investigated. By using the fixed point theory and Liapunov functional, we prove that a recurrent neural network might have a unique equilibrium point which is unstable. This particular type of instability, combined with the boundedness of the solutions of the system, will force the network to generate a permanent oscillation. Some necessary and sufficient conditions for these oscillations are obtained. Simple and practical criteria for fixing the range of parameters in this network are also derived. Typical simulation examples are presented.
Autors: Feng, C.;Plamondon, R.;O'Reilly, C.;
Appeared in: IEEE Transactions on Neural Networks
Publication date: Aug 2010, volume: 21, issue:8, pages: 1197 - 1205
Publisher: IEEE
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» On Successive Refinement for the Kaspi/Heegard–Berger Problem
Abstract:
Consider a source that produces independent copies of a triplet of jointly distributed random variables . The process is observed at the encoder, and is supposed to be reproduced at two decoders, decoder Y and decoder Z, where and are observed, respectively, in either a causal or noncausal manner. The communication between the encoder and the decoders is carried in two successive stages. In the first stage, the transmission is available to both decoders and they reconstruct the source according to the received bit-stream and the individual side information ( or ). In the second stage, additional information is sent to both decoders and they refine the reconstructions of the source according to the available side information and the transmissions at both stages. It is desired to find the necessary and sufficient conditions on the communication rates between the encoder and decoders, so that the distortions incurred (at each stage) will not exceed given thresholds. For the case of causal availability of side information at the decoders, an exact single-letter characterization of the achievable region is derived for the case of pure source-coding. Then, for the case of communication between the encoder and decoders carried over i- - ndependent memoryless discrete channels with random states known causally/noncausally at the encoder and with causal side information about the source at the decoders, a single-letter characterization of all achievable distortion in both stages is provided and it is shown that the separation theorem holds. The results are derived without assuming any structural restrictions on side information, such as a Markov structure, etc. Finally, for noncausal degraded side information, inner and outer bounds to the achievable rate-distortion region are derived. These bounds are shown to be tight for certain cases of reconstruction requirements at the decoders. Due to the system setup, these results also shed some light on a problem of successive refinement with side information which is not degraded in the usual sense.
Autors: Maor (Varshavsky), A.;Merhav, N.;
Appeared in: IEEE Transactions on Information Theory
Publication date: Aug 2010, volume: 56, issue:8, pages: 3930 - 3945
Publisher: IEEE
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» On the accuracy of current TCAD hot carrier injection models in nanoscale devices
Abstract:
In this work, the hot electron injection models presently available for technology support have been investigated within the context of the development of advanced embedded non-volatile memories. The distribution functions obtained by these models (namely the Fiegna Model - FM [1], the Lucky Electron Model - LEM [2] and the recently implemented Spherical Harmonics Expansion of the Boltzman's Transport Equation - SHE [3]), have been systematically compared to rigorous Monte Carlo (MC) results [4], both in homogeneous and device conditions. Gate-to-drain current ratio and gate current density simulation has also been benchmarked in device simulations.Results indicate that local models such...
Autors: Alban, Zaka , Quentin, Rafhay , Matteo, Iellina , Pierpaolo, Palestri , Raphaël, Clerc , ...
Appeared in: Solid-State Electronics
Publication date: Aug 2010
Publisher: Elsevier B.V.
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» On the Achievable Diversity Orders over Non-Severely Faded Lognormal Channels
Abstract:
We propose to approximate the distribution of the sum of identically-distributed lognormal random variables by an Erlang distribution. The advantage of the proposed approximation over the lognormal and non-lognormal approximations proposed in the literature resides mainly in the fact that it results in simple closed-form expressions of the average bit-error-rate (BER) thus offering clear insights on the performance of diversity combining techniques over correlated and uncorrelated lognormal fading channels. For instance, the proposed approach shows that, for typical values of the BER, the diversity order in the case of non-severe lognormal fading can be accurately approximated by the order of the approximating Erlang distribution.
Autors: Abou-Rjeily, Chadi;Bkassiny, Mario;
Appeared in: IEEE Communications Letters
Publication date: Aug 2010, volume: 14, issue:8, pages: 695 - 697
Publisher: IEEE
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» On the Analytic Wavelet Transform
Abstract:
An exact and general expression for the analytic wavelet transform of a real-valued signal is constructed, resolving the time-dependent effects of nonnegligible amplitude and frequency modulation. The analytic signal is first locally represented as a modulated oscillation, demodulated by its own instantaneous frequency, and then Taylor-expanded at each point in time. The terms in this expansion, called the instantaneous modulation functions, are time-varying functions which quantify, at increasingly higher orders, the local departures of the signal from a uniform sinusoidal oscillation. Closed-form expressions for these functions are found in terms of Bell polynomials and derivatives of the signal's instantaneous frequency and bandwidth. The analytic wavelet transform is shown to depend upon the interaction between the signal's instantaneous modulation functions and frequency-domain derivatives of the wavelet, inducing a hierarchy of departures of the transform away from a perfect representation of the signal. The form of these deviation terms suggests a set of conditions for matching the wavelet properties to suit the variability of the signal, in which case our expressions simplify considerably. One may then quantify the time-varying bias associated with signal estimation via wavelet ridge analysis, and choose wavelets to minimize this bias.
Autors: Lilly, J. M.;Olhede, S. C.;
Appeared in: IEEE Transactions on Information Theory
Publication date: Aug 2010, volume: 56, issue:8, pages: 4135 - 4156
Publisher: IEEE
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» On the Annotation of Web Videos by Efficient Near-Duplicate Search
Abstract:
With the proliferation of Web 2.0 applications, user-supplied social tags are commonly available in social media as a means to bridge the semantic gap. On the other hand, the explosive expansion of social web makes an overwhelming number of web videos available, among which there exists a large number of near-duplicate videos. In this paper, we investigate techniques which allow effective annotation of web videos from a data-driven perspective. A novel classifier-free video annotation framework is proposed by first retrieving visual duplicates and then suggesting representative tags. The significance of this paper lies in the addressing of two timely issues for annotating query videos. First, we provide a novel solution for fast near-duplicate video retrieval. Second, based on the outcome of near-duplicate search, we explore the potential that the data-driven annotation could be successful when huge volume of tagged web videos is freely accessible online. Experiments on cross sources (annotating Google videos and Yahoo! videos using YouTube videos) and cross time periods (annotating YouTube videos using historical data) show the effectiveness and efficiency of the proposed classifier-free approach for web video tag annotation.
Autors: Zhao, W.-L.;Wu, X.;Ngo, C.-W.;
Appeared in: IEEE Transactions on Multimedia
Publication date: Aug 2010, volume: 12, issue:5, pages: 448 - 461
Publisher: IEEE
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» On the Broadcast Capacity of Wireless Networks With Cooperative Relays
Abstract:
A fundamental problem in wireless networks is determining the broadcast capacity, i.e., the maximum data transfer rate from a given node to every other node in a relay network. This paper studies the scaling of the broadcast capacity for a network with a single source and destinations, of which are randomly selected to also act as relays. In high-density networks (i.e., the node density goes to infinity; the network area is fixed), it is shown that the broadcast capacity is upper bounded by . Schemes are provided that achieve i) throughput if the channel fading is spatially continuous; ii) throughput if the channel fading is spatially i.i.d.. For extended networks (i.e., the node density is fixed; the network area goes to infinity), the broadcast capacity is upper bounded by under channel models with fading and path-loss exponent . A multistage cooperative broadcasting scheme, which achieve- - s broadcast rate for the high-density extended networks with pathloss channel model is proposed. These results quantifies the gains obtained due to cooperation compared to multihop noncooperative broadcasting, which has a maximum rate that scales as for high-density and for extended networks.
Autors: Sirkeci-Mergen, B.;Gastpar, M. C.;
Appeared in: IEEE Transactions on Information Theory
Publication date: Aug 2010, volume: 56, issue:8, pages: 3847 - 3861
Publisher: IEEE
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» On the Characterization of Strict Positive Realness for General Matrix Transfer Functions
Abstract:
We present conditions which are necessary and sufficient for a transfer function (or transfer function matrix) to be strictly positive real. A counter-example is given to illustrate that the conditions presented here differ from those previously presented in the literature. The proof of our results differs from previous related proofs in that it only uses properties of analytic functions and matrices and does not require state-space realizations. Also, the results are not restricted to rational transfer functions with real coefficients.
Autors: Corless, M.;Shorten, R.;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Aug 2010, volume: 55, issue:8, pages: 1899 - 1904
Publisher: IEEE
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» On the Convergence of Planar Curves Under Smoothing
Abstract:
Curve smoothing has two important applications in computer vision and image processing: 1) the curvature scale-space (CSS) technique for shape analysis, and 2) the Gaussian filter for noise suppression. In this paper, we study how planar curves converge as they are smoothed with increasing scales. First, two types of convergence behavior are clarified. The coined term shrinkage refers to the reduction of arc-length of a smoothed planar curve, which describes the convergence of the curve latitudinally; and another coined term collapse refers to the movement of each point to its limiting position, which describes the convergence of the curve longitudinally. A systematic study on the shrinkage and collapse of three categories of curve models is then presented. The corner models helps to reveal how the local structures of planar curves collapse and what the smoothed curves may converge to. The sawtooth models allows us to gain insights regarding how noise is suppressed from noisy planar curves by the Gaussian filter. Our investigation on the closed curves shows that each curve collapses to a point at its center of mass. However, different curves may yield different limiting shapes at the infinity scale. Finally, based upon the derived results the performance of the CSS technique in corner detection and shape representation is analyzed, and a fast implementation method of the Gaussian filter for noise suppression is proposed.
Autors: Zhong, B.;Ma, K.-K.;
Appeared in: IEEE Transactions on Image Processing
Publication date: Aug 2010, volume: 19, issue:8, pages: 2171 - 2189
Publisher: IEEE
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» On the Cyclostationarity of OFDM and Single Carrier Linearly Digitally Modulated Signals in Time Dispersive Channels: Theoretical Developments and Application
Abstract:
Previous studies on the cyclostationarity aspect of orthogonal frequency division multiplexing (OFDM) and single carrier linearly digitally modulated (SCLD) signals assumed simplified signal and channel models or considered only second-order cyclostationarity. This paper presents new results concerning the cyclostationarity of these signals under more general conditions, including time dispersive channels, additive Gaussian noise, and carrier phase, frequency, and timing offsets. Analytical closed-form expressions are derived for time- and frequency-domain parameters of the cyclostationarity of OFDM and SCLD signals. In addition, a condition to eliminate aliasing in the cycle and spectral frequency domains is derived. Based on these results, an algorithm is developed for recognizing OFDM versus SCLD signals. This algorithm obviates the need for commonly required signal preprocessing tasks, such as signal and noise power estimation and the recovery of symbol timing and carrier information.
Autors: Punchihewa, A.;Zhang, Q.;Dobre, O. A.;Spooner, C.;Rajan, S.;Inkol, R.;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Aug 2010, volume: 9, issue:8, pages: 2588 - 2599
Publisher: IEEE
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» On the Distribution of Signal Phase in Body Area Networks
Abstract:
In this letter, we investigate the distribution of the phase component of the complex received signal observed in practical experiments using body area networks. Two phase distributions, the recently proposed κ-μ and η-μ probability densities, which together encompass the most widely used fading models, namely Semi-Gaussian, Rayleigh, Hoyt, Rice, and Nakagami-m, have been compared with measurement data. The κ-μ distribution has been found to provide the best fit over a range of on-body links, while the user was mobile. The experiments were carried out in two dissimilar indoor environments at opposite ends of the multipath spectrum. It has also been found that the uniform phase distribution has not arisen in anyone of the experiments.
Autors: Cotton, Simon L.;Dias, Ugo S.;Scanlon, William G.;Yacoub, Michel D.;
Appeared in: IEEE Communications Letters
Publication date: Aug 2010, volume: 14, issue:8, pages: 728 - 730
Publisher: IEEE
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» On the Equivalence of a Conducting Plate in a Laboratory Experiment to a Real Earth
Abstract:
This paper investigates the validity and the application limit of experimental results on a scale model above a conducting plate, such as an aluminum (Al) or copper (Cu) plate, representing a real power system, which is too large for experimental measurements. The surge characteristics on a scale model of an overhead conductor above an Al plate are compared with that above a real earth. The experimental results are compared with analytical and numerical simulation results by the electromagnetic transients program and finite-difference time domain method. It is clear that the Al plate can represent the real earth only for an initial part of a surge waveform until reflection comes back from the other end of the conductor. The surge waveform on the Al plate noticeably deviates from that on the real earth as time passes. Correspondingly, the characteristic impedance of the Al plate differs from that on the real earth depending on the conductor height and the separation between the conductors.
Autors: Ametani, A.;Nishitsuji, M.;Nagaoka, N.;Baba, Y.;Okabe, S.;
Appeared in: IEEE Transactions on Electromagnetic Compatibility
Publication date: Aug 2010, volume: 52, issue:3, pages: 691 - 698
Publisher: IEEE
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» On the Equivalence of Finite Element and Finite Integration Formulations
Abstract:
The paper offers a comparative study of numerical methods of analysis of electromagnetic fields. The focus is on the finite element method (FEM) and finite integration technique (FIT), but with the cell and equivalent network approaches also considered. It is shown how the approximate integrals describing coefficients of the FEM need to be derived for a mesh with parallelepiped elements to achieve consistency with FIT equations. The equivalence of FEM and FIT formulations for a triangular mesh in 2D is highlighted. The TEAM Workshops Problem No. 7 is used as an example for numerical comparisons. Two formulations have been considered: 1) using the edge values of the magnetic vector potential and the nodal values of the electric scalar potential ; and 2) expressed in terms of the edge values of both magnetic and electric - vector potentials.
Autors: Demenko, A.;Sykulski, J. K.;Wojciechowski, R.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Aug 2010, volume: 46, issue:8, pages: 3169 - 3172
Publisher: IEEE
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» On the FDTD Near-to-Far-Field Transformations for Weakly Scattering Objects
Abstract:
Recently published papers on the near-to-far-field (NTFF) transformation in the finite-difference time-domain (FDTD) method have demonstrated accuracy improvements for weakly scattering objects. The improvements are achieved by modifications of the “standard” NTFF transformation which is based on interpolation of the spatially shifted fields in the FDTD grid. In this paper, it is shown that accurate results can be obtained for such weakly scattering objects without the suggested improvements, provided that the correct FDTD NTFF transformation is used. “Correct” is referred to a transformation procedure that is consistent with the FDTD version of the equivalence principle. This NTFF transformation procedure was published in the IEEE Transactions on Antennas and Propagation in 1998. Recently published results for weakly scattering objects have been reproduced using this NTFF transformation.
Autors: Martin, T.;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Aug 2010, volume: 58, issue:8, pages: 2794 - 2795
Publisher: IEEE
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» On the fractional signals and systems
Abstract:
A look into Fractional Calculus and their applications from the Signal Processing point of view is done in this paper. A coherent approach to the fractional derivative is presented leading to notions that are, not only compatible with the classic, but constitute a true generalization. This means that the classic are recovered when the fractional domain is left. This happens in particular with the impulse response and transfer function. An interesting feature of the systems is in the causality that the fractional derivative imposes. The main properties of the derivatives and their representations are presented. A brief and general study...
Autors: Richard, Magin , Manuel D., Ortigueira , Igor, Podlubny , Juan, Trujillo
Appeared in: Signal Processing
Publication date: Aug 2010
Publisher: Elsevier B.V.
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» On the geometric and dynamic structures of the optimal and central controllers?
Abstract:
In this paper, the geometric structure of observer-based controllers is investigated in order to characterize the controllable and unobservable subspaces of the optimal and the central controllers. It is shown that the controllable and unobservable subspaces of the optimal and the central controllers can be characterized by the kernel and image subspaces of the solutions of two Lyapunov equations. Under this characterization, the connection between the geometric subspaces and the dynamic behavior of the plant and those of the optimal and controllers is derived. It is also shown that the optimal and the...
Autors: Po-Feng, Wu , Chee-Fai, Yung
Appeared in: Automatica
Publication date: Aug 2010
Publisher: Elsevier B.V.
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» On the Importance of Incorporating Iron Losses in the Magnetic Field Solution of Electrical Machines
Abstract:
This paper studies the effects of iron losses on the magnetic field solution and evaluates their impacts on the overall performance of electrical machines. Because of the complications associated with the inclusion of iron losses into the magnetic field solution, the losses are usually omitted from the finite-element (FE) analysis while they are estimated in a post-processing stage. We conducted a comprehensive FE analysis to study how the iron losses affect the accuracy of the magnetic field solution and what kind of role the losses play in defining the behavior and operation of electrical machines. We found that the inclusion of iron losses in the FE field solution of rotating electrical machines is primarily important for predicting iron losses accurately. Other electrical and mechanical quantities, including input power, supply current, power factor, copper losses, and rotational speed are only slightly affected by iron losses. Therefore, we have proposed an empirical equation that can be used to correct the iron losses that are calculated from the post-processing of the FE solution.
Autors: Dlala, E.;Belahcen, A.;Arkkio, A.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Aug 2010, volume: 46, issue:8, pages: 3101 - 3104
Publisher: IEEE
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» On the Influence of Weather Forecast Errors in Short-Term Load Forecasting Models
Abstract:
Weather information is an important factor in load forecasting models. Typically, load forecasting models are constructed and tested using actual weather readings. However, online operation of load forecasting models requires the use of weather forecasts, with associated weather forecast errors. These weather forecast errors inevitably lead to a degradation in model performance. This is an important factor in load forecasting but has not been widely examined in the literature. The main aim of this paper is to present a novel technique for minimizing the consequences of this degradation. In addition, a supplementary technique is proposed to model weather forecast errors to reflect current accuracy.
Autors: Fay, D.;Ringwood, J. V.;
Appeared in: IEEE Transactions on Power Systems
Publication date: Aug 2010, volume: 25, issue:3, pages: 1751 - 1758
Publisher: IEEE
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» On the Maximum Bandwidth Attainable by Power Factor Correctors With a Standard Compensator
Abstract:
When a power factor corrector (PFC) is designed with a relatively fast output-voltage feedback loop, the static and dynamic behaviors of the power stage are different from those obtained with a slow output-voltage feedback loop. This is because of the influence of the voltage ripple that is present on the control signal. This voltage ripple generates a “parasitic” feedback loop, which is different from the “desired” one (the dc output-voltage feedback loop). The effect of this “parasitic” feedback loop can be integrated into the power stage model in such a way that a new model for the power stage is obtained. Assuming this model, the only feedback loop is the one corresponding to the dc output voltage, i.e., the “desired” output-voltage feedback loop. The design of this feedback loop determines the final dynamic behavior of the PFC, which can be optimized to achieve the maximum bandwidth compatible with compliance with existing regulations regarding the injection of line harmonics and PFC stability. The main objective of this paper is, thus, to determine the maximum crossover angular frequency compatible with a desired value of the phase margin and that complies with EN 61000-3-2 regulations in all possible classes of equipment (A, B, C, and D) when a standard compensator (a PI with one additional pole) is used. The results obtained show that the maximum bandwidth attainable by a PFC strongly depends on its class. This maximum bandwidth depends on the power processed by the converter in the case of equipment classified as Class A or Class B. However, the maximum bandwidth attainable for equipment belonging to Class C or to Class D does not depend on the power processed and is always higher in the case of Class D than in that of Class C.
Autors: Sebastian, J.;Lamar, D. G.;Rodriguez-Alonso, A.;Arias Perez de Azpeitia, M.;Fernandez Gonzalez, A.;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Aug 2010, volume: 46, issue:4, pages: 1485 - 1497
Publisher: IEEE
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» On the Maximum Efficiency of Systems Containing Multiple Sources
Abstract:
This paper deals with the efficiency of systems consisting of multiple power sources. The operating point ensuring maximum efficiency is defined and solved analytically. Moreover, it is shown that, in the case of linear sources, the maximum efficiency is determined solely by the load power and the network's maximum power, independently of the sources' internal construction and their connectivity. The generic circuit theory treatment that is proposed applies to distributed power generation (smart grid, photovoltaic, fuel cells, etc.) and to distributed load systems (LED arrays, microprocessors).
Autors: Levron, Y.;Shmilovitz, D.;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Aug 2010, volume: 57, issue:8, pages: 2232 - 2241
Publisher: IEEE
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» On the mechanical interaction of a boa constrictor and its prey
Abstract:
The rather gruesome title provides the inspiration for an example involving the interaction between two different nonlinear viscoelastic material models. The boa constrictor is modeled as a circular band of muscle that can contract while exhibiting nonlinear viscoelastic tensile properties. It is wrapped around a prey whose chest and lungs are modeled as a cylinder of a compressible nonlinear viscoelastic material. Contraction results in tension in the muscle and a radial compressive load on the cylinder. It is assumed that the boa constrictor, as would a human, feels discomfort when its muscle tension becomes too large. The initial muscle contraction...
Autors: Alan, Wineman
Appeared in: International Journal of Engineering Science
Publication date: Aug 2010
Publisher: Elsevier B.V.
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» On the Optimization for Enhanced Dual-Pulse Laser-Induced Breakdown Spectroscopy
Abstract:
We present a systematic study on the optimization of the following: 1) interpulse delay; 2) the pulse energies ratio; and 3) the combination of laser wavelengths to achieve the signal enhancement in double-pulse laser-induced breakdown spectroscopy (LIBS) on magnesium target using two Nd:YAG lasers in collinear configuration. More than 350 times signal intensity enhancement is achieved in the neutral magnesium lines on an appropriate combination of laser wavelengths with the optimized values of the interpulse delay and the laser pulse energies ratio.
Autors: Ahmed, R.;Baig, M. A.;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Aug 2010, volume: 38, issue:8, pages: 2052 - 2055
Publisher: IEEE
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» On the Performance of IEEE 802.11e Wireless Infrastructures for Soft-Real-Time Industrial Applications
Abstract:
Nowadays, wireless communication technologies are being employed in an ever increasing number of different application areas, including industrial environments. Benefits deriving from such a choice are manifold and include, among the others, reduced deployment costs, enhanced flexibility and support for mobility. Unfortunately, because of a number of reasons that have been largely debated in the literature, wireless systems cannot be thought of as a means able to fully replace wired networks in production plants, in particular, when real-time behavior is a key issue.
Autors: Cena, G.;Seno, L.;Valenzano, A.;Zunino, C.;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Aug 2010, volume: 6, issue:3, pages: 425 - 437
Publisher: IEEE
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» On the Power Management of Simultaneous Multithreading Processors
Abstract:
Simultaneous multithreading (SMT) processors are widely used in high performance computing tasks. However, with the improved performance of the SMT architecture, the utilization of their functional units is significantly increased, straining the power budget of the processor. This increases not only the dynamic power consumption, but also the leakage power consumption due to the increased temperature. In this paper, a comparison of the static and dynamic sleep signal generation techniques for SMT processors is presented. This is conducted under various workloads to assess their effectiveness in leakage power management. Results show that the dynamic approach exhibits a threefold increase in leakage savings, compared with that of the static approach for certain functional units.
Autors: Youssef, A.;Zahran, M.;Anis, M.;Elmasry, M.;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Aug 2010, volume: 18, issue:8, pages: 1243 - 1248
Publisher: IEEE
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» On the Resistance of Boolean Functions Against Algebraic Attacks Using Univariate Polynomial Representation
Abstract:
In the past few years, algebraic attacks against stream ciphers with linear feedback function have been significantly improved. As a response to the new attacks, the notion of algebraic immunity of a Boolean function was introduced, defined as the minimum degree of the annihilators of and . An annihilator of is a nonzero Boolean function , such that . While several constructions of Boolean functions with optimal algebraic immunity have been proposed, there is no significant progress concerning the resistance against the so-called fast algebraic attacks. In this paper, we provide a framework to assess the resistance of Boolean functions against the new algebraic attacks, including fast algebraic attacks. The analysis is based on the univariate polynomial representation of Boolean functions and necessary and sufficient conditions are presented for a Boolean function to have optimal behavior against all the new algebraic attacks. Finally, we introduce a new infinite family of balanced Boolean functions described by their univariate polynomial representation. By applying the new framework, we prove that all the members of the family have optimal algebraic immunity and we efficiently evaluate their behavior against fast algebraic attacks.
Autors: Rizomiliotis, P.;
Appeared in: IEEE Transactions on Information Theory
Publication date: Aug 2010, volume: 56, issue:8, pages: 4014 - 4024
Publisher: IEEE
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» On the Seamless Interconnection of IEEE1588-Based Devices Using a PROFINET IO Infrastructure
Abstract:
Several types of industrial Real-Time Ethernet (RTE) networks could be present in the same plant. This work deals with the clock synchronization problems that arise when different RTE network infrastructures are interconnected. Specifically, this paper is focused on the exploitation of PROFINET IO Conformance Class C infrastructure for the interconnection of other industrial communication devices or measurement instruments that use IEEE1588 for clock synchronization. Actually, such devices (e.g., LXI instruments, EtherNet/IP devices, etc.) cannot be satisfactorily synchronized if directly connected to the PROFINET infrastructure, because of the large time errors (up to 100 ). The solution proposed in this paper is an intelligent clock synchronization converter that has fewer limitations if compared with other systems, like boundary clocks. The basic idea is the creation of a “black-box” (a sort of remote bridging device) for the interconnection of IEEE1588 nodes through a PROFINET IO host plant, with zero-configuration on both systems. The proposed approach differs from boundary clock since its goal is to keep the PROFINET IO and the IEEE1588 synchronization domains separated, exploiting the possibility to tunnel the IEEE1588 time information through the PROFINET IO infrastructure with sufficient precision.
Autors: Ferrari, P.;Flammini, A.;Rinaldi, S.;Sisinni, E.;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Aug 2010, volume: 6, issue:3, pages: 381 - 392
Publisher: IEEE
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» On the Selection of Weight Decay Parameter for Faulty Networks
Abstract:
The weight-decay technique is an effective approach to handle overfitting and weight fault. For fault-free networks, without an appropriate value of decay parameter, the trained network is either overfitted or underfitted. However, many existing results on the selection of decay parameter focus on fault-free networks only. It is well known that the weight-decay method can also suppress the effect of weight fault. For the faulty case, using a test set to select the decay parameter is not practice because there are huge number of possible faulty networks for a trained network. This paper develops two mean prediction error (MPE) formulae for predicting the performance of faulty radial basis function (RBF) networks. Two fault models, multiplicative weight noise and open weight fault, are considered. Our MPE formulae involve the training error and trained weights only. Besides, in our method, we do not need to generate a huge number of faulty networks to measure the test error for the fault situation. The MPE formulae allow us to select appropriate values of decay parameter for faulty networks. Our experiments showed that, although there are small differences between the true test errors (from the test set) and the MPE values, the MPE formulae can accurately locate the appropriate value of the decay parameter for minimizing the true test error of faulty networks.
Autors: Leung, C. S.;Wang, H.-J.;Sum, J.;
Appeared in: IEEE Transactions on Neural Networks
Publication date: Aug 2010, volume: 21, issue:8, pages: 1232 - 1244
Publisher: IEEE
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» On the Sum Rate of Gaussian Multiterminal Source Coding: New Proofs and Results
Abstract:
We show that the lower bound on the sum rate of the direct and indirect Gaussian multiterminal source coding problems can be derived in a unified manner by exploiting the semidefinite partial order of the distortion covariance matrices associated with the minimum mean squared error (MMSE) estimation and the so-called reduced optimal linear estimation, through which an intimate connection between the lower bound and the Berger-Tung upper bound is revealed. We give a new proof of the minimum sum rate of the indirect Gaussian multiterminal source coding problem (i.e., the Gaussian CEO problem). For the direct Gaussian multiterminal source coding problem, we derive a general lower bound on the sum rate and establish a set of sufficient conditions under which the lower bound coincides with the Berger-Tung upper bound. We show that the sufficient conditions are satisfied for a class of sources and distortion constraints; in particular, they hold for arbitrary positive definite source covariance matrices in the high-resolution regime. In contrast with the existing proofs, the new method does not rely on Shannon's entropy power inequality.
Autors: Wang, J.;Chen, J.;Wu, X.;
Appeared in: IEEE Transactions on Information Theory
Publication date: Aug 2010, volume: 56, issue:8, pages: 3946 - 3960
Publisher: IEEE
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» On the Vision of Complete Fixed-Mobile Convergence
Abstract:
This paper reviews and outlines the key features of the emerging next-generation fixed passive optical network (NG-PON)-based and fourth-generation (4G) mobile broadband access technologies and how to leverage the advantages of both of these access technologies to build a next-generation hybrid fiber-wireless (FiWi) network. Specifically, this paper presents an overview of the most recent research activities on these hybrid FiWi architectures, aiming to clarify the basic differences and distinguish between two FiWi networking architectural models, namely, the overlay or independent model and the truly integrated model. We then explore and present a new direction to the design and implementation of a simple and cost-effective all-packet-based converged fixed-mobile access networking solution that enables the true integration of NG-PON and 4G mobile broadband access technologies into the envisioned fixed-mobile platform. We briefly outline the general and technical requirements to support a unified NG-PON long-term evolution ((LTE) radio access network (RAN) architecture that conforms to both the typically centralized fixed PON and the emerging distributed 4G mobile LTE access standards. The implementation methodology on how to efficiently and cost-effectively integrate these two access technologies along with the main advantages gained from such an integrated architecture are outlined and presented.
Autors: Ali, M. A.;Ellinas, G.;Erkan, H.;Hadjiantonis, A.;Dorsinville, R.;
Appeared in: Journal of Lightwave Technology
Publication date: Aug 2010, volume: 28, issue:16, pages: 2343 - 2357
Publisher: IEEE
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» On-chip networks: Two sides of the same coin
Abstract:
Two key concepts that will drive design in future years are low power and network design. Although at times it has been nearly impossible to understand what a certain design can or can't do for an application, things have improved lately thanks to the NoC benchmarking initiative. Now, for example, various optimizations can be compared and contrasted, using the same set of benchmarks, to understand what benefits—for instance, in terms of performance or energy—a network-based approach can bring to an application. It's necessary, however, to dig much deeper into the science of networks, and reach beyond the established confines of digital design if the potential of this new design paradigm is to be harnessed.
Autors: Marculescu, Radu;
Appeared in: IEEE Design & Test of Computers
Publication date: Aug 2010, volume: 27, issue:4, pages: 80 - 80
Publisher: IEEE
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» One-chip integrated polarisation-multiplexed DQPSK demodulator using silica-based planar lightwave circuit technology
Abstract:
A compact polarisation-multiplexed differential quadrature phase-shift keying (DQPSK) demodulator achieved by integrating a polarisation beam splitter and two DQPSK demodulators consisting of a delay interferometer and a 90°-hybrid using silica-based planar lightwave circuit technology is demonstrated. The optical characteristics of the fabricated demodulator were sufficient for the direct detection of 100 Gbit/s polarisation-multiplexed DQPSK signals.
Autors: Sakamaki, Y.;Hattori, K.;Nasu, Y.;Hashimoto, T.;Hashizume, Y.;Mizuno, T.;Goh, T.;Takahashi, H.;
Appeared in: Electronics Letters
Publication date: Aug 2010, volume: 46, issue:16, pages: 1152 - 1154
Publisher: IEEE
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» Online Monitoring of Voltage Stability Margin Using an Artificial Neural Network
Abstract:
In this paper, an artificial neural network (ANN) based method is developed for quickly estimating the long-term voltage stability margin. The investigation presented in the paper showed that node voltage magnitudes and the phase angles are the best predictors of voltage stability margin. Further, the paper shows that the proposed ANN based method can successfully estimate the voltage stability margin not only under normal operation but also under N-1 contingency situations. If the voltage magnitudes and phase angles are obtained in real-time from phasor measurement units (PMUs) using the proposed method, the voltage stability margin can be estimated in real time and used for initiating stability control actions. Finally, a suboptimal approach to determine the best locations for PMUs is presented. Numerical examples of the proposed techniques are presented using the New England 39-bus test system and a practical power system which consists of 1844 buses, 746 load buses, and 302 generator buses.
Autors: Zhou, D. Q.;Annakkage, U. D.;Rajapakse, A. D.;
Appeared in: IEEE Transactions on Power Systems
Publication date: Aug 2010, volume: 25, issue:3, pages: 1566 - 1574
Publisher: IEEE
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» Online Packet Loss Measurement and Estimation for VPN-Based Services
Abstract:
When provisioning quantitative quality of service (QoS) for virtual private network (VPN) services over packet switched networks, parameters such as packet loss, delay, and delay jitter, besides the required bandwidth, have to be guaranteed. While the bandwidth is relatively easier to guarantee, maintaining a value of the packet loss parameter below a preset value presents great interests but serious difficulties. One of the key issues is to link the stochastic characteristics of the input process to the packet loss probability (PLP), i.e., how one can accurately estimate the PLP based on measurements of the input process. This is crucial for building transducers for control loops meant for keeping the packet loss parameter within the guaranteed limits as specified by the service level agreement (SLA). Although the estimation of the PLP has been studied by many researchers, little has been done in regard to the estimators of the packet loss parameter such that the latter can be used in online applications. This paper studies the PLP estimation problem from a transducer and, hence, a control system perspective, and evaluates the quality of the proposed solutions through live network experimental data. Two asymptotic estimation formulas for loss probability are derived by applying the large deviation theory (LDT) on the buffer overflow probability and proposed as mathematical relations to be used by the online transducer.
Autors: Zhang, D.;Ionescu, D.;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Aug 2010, volume: 59, issue:8, pages: 2154 - 2166
Publisher: IEEE
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» Onsager reciprocity as a consequence of Maxwell reciprocity for "equidiffuse" fluids
Abstract:
Linear irreversible thermodynamics (LIT) principles are used to show, in the hypothetical "equidiffuse" case where all of the various phenomenological diffusion coefficients appearing in the linear near-equilibrium constitutive laws governing the diffuse transport of energy, multicomponent species, entropy, and volume (although not necessarily including momentum) are taken to be equal, that the Onsager reciprocal relations pertinent to nonequilibrium thermodynamics follow automatically from Maxwell's reciprocal relations governing equilibrium thermodynamics. As such, this constitutes a purely macroscopic proof of Onsager reciprocity, the first of its kind. Although the equality of diffusion coefficients required in the equidiffuse limiting case does not represent a...
Autors: Howard, Brenner
Appeared in: International Journal of Engineering Science
Publication date: Aug 2010
Publisher: Elsevier B.V.
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» Onset Characteristics of Aqueous Large Gap Electrosprays
Abstract:
Electrosprays (ESs) have a wide variety of applications. In particular, the onset voltage parameter is of special interest. Our study investigated onset characteristics of aqueous ESs in a negative polarity for capillary tip-plate distances in the range of 0.5–50 cm. Experiments show significant variation of onset voltage with the presence of metal objects in the proximity of the ES. Data analysis shows an increase in onset voltage with the decrease in counterelectrode radius. The region least sensitive to such variation was found for tip-plate distances larger than 20 cm. Onset voltages appear to be in agreement with Smith's formula for a certain range of the distance studied. Gaps larger than 25 cm have generally shown more significant variations of this formula. The results of the present study can be useful for the design of ESs of larger gaps.
Autors: Ieta, A.;Quill, D.;Doyle, T. E.;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Aug 2010, volume: 46, issue:4, pages: 1601 - 1605
Publisher: IEEE
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» Open-hardware e-puck Linux extension board for experimental swarm robotics research
Abstract:
In this paper we describe the implementation of a Linux extension board for the e-puck educational mobile robot, designed to enhance the computation, memory and networking performance of the robot at very low cost. The extension board is based on a 32-bit ARM9 microprocessor and provides wireless network support. The ARM9 extension board runs in parallel with the dsPIC microprocessor on the e-puck motherboard with communication between the two via an SPI bus. The extension board is designed to handle computationally intensive image processing, wireless communication and high-level intelligent robot control algorithms, while the dsPIC handles low-level sensor interfacing, data...
Autors: Wenguo, Liu , Alan FT, Winfield
Appeared in: Microprocessors and Microsystems
Publication date: Aug 2010
Publisher: Elsevier B.V.
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» Operating Temperature Trends in Amorphous In–Ga–Zn–O Thin-Film Transistors
Abstract:
The electrical performance as a function of operating temperature of amorphous indium gallium zinc oxide (a-IGZO) thin-film transistors (TFTs) is assessed by measuring drain current versus gate voltage [ ] transfer curves at temperatures from to . These bottom-gate staggered a-IGZO TFTs are fabricated using thermal silicon dioxide as the gate insulator. An almost rigid transfer curve shift to lower (more negative) turn-on voltage with increasing temperature is observed. The extent of the operating temperature dependence of a TFT appears to be correlated to its trap density. A lower trap density gives rise to less operating temperature dependence. Although transfer curves are observed to shift almost rigidly with temperature, a more detailed temperature-dependence assessment indicates that the shift is not exactly rigid. The mobility is found to increase slightly with increasing operating temperature. This trend is attributed to enhanced detrapping at a higher operating temperature.
Autors: Hoshino, K.;Wager, J. F.;
Appeared in: IEEE Electron Device Letters
Publication date: Aug 2010, volume: 31, issue:8, pages: 818 - 820
Publisher: IEEE
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» Optical CDMA system using 2-D run-length limited code?
Abstract:
In this paper, time-spreading wavelength-hopping optical CDMA system using 2-D run-length limited code is investigated. The run-length limited code we use here is predicated upon spatial coding scheme, which can improve system performance significantly. In our proposed system, we employ carrier-hopping prime code and its shifted version as signature sequences. Based on the zero auto-correlation sidelobes property of signature sequence, we propose a two-state trellis coding architecture, which utilizes 2-D parallel detection scheme. The proposed scheme is compact and simple that can be applied to more complicated trellis to further enhance system performance. Multiple access interference is the main deterioration...
Autors: Maw-Yang, Liu , Joe-Air, Jiang
Appeared in: Optical Fiber Technology
Publication date: Aug 2010
Publisher: Elsevier B.V.
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» Optical Chip-to-Chip Link System by Using Optical Wiring Method for Reducing EMI
Abstract:
This paper describes a new optical link system which consists of a metal optical bench, a module printed circuit board, a driver/receiver integrated circuit, a vertical-cavity surface-emitting laser/photo diode (VCSEL/PD) array, and an optical link block with plastic optical fibers for reducing electromagnetic interference (EMI) noise. For the optical interconnection between the light-sources and detectors, an optical wiring method whose distinctive features include the absence of EMI noise and easy assembly is proposed. The results clearly demonstrate that the use of an optical wiring method can provide robust, cost-effective assembly and easy-repair. We successfully achieved a 4.5 Gb/s data transmission rate without EMI problems.
Autors: Cho, I.-K.;Yun, J.-H.;Jeong, M.-Y.;Park, H.-H.;
Appeared in: IEEE Transactions on Advanced Packaging
Publication date: Aug 2010, volume: 33, issue:3, pages: 722 - 728
Publisher: IEEE
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» Optical coherence tomography monitoring of angioplasty balloon inflation in a deployment tester
Abstract:
We present an innovative integration of an intravascular optical coherence tomography probe into a computerized balloon deployment system to monitor the balloon inflation process. The high-resolution intraluminal imaging of the balloon provides a detailed assessment of the balloon quality and, consequently, a technique to improve the balloon manufacturing process. A custom-built swept-source optical coherence tomography system is used for real-time imaging. A semicompliant balloon with a nominal diameter of 4 mm is fabricated for the experiments. Imaging results correspond to balloon deployment in air and inside an artery phantom. A characterization of the balloon diameter, wall thickness, compliance, and elastic modulus is provided, based on image segmentation. Using the images obtained from the probe pullback, a three-dimensional visualization of the inflated balloon is presented.
Autors: Azarnoush, Hamed;Vergnole, Sebastien;Bourezak, Rafik;Boulet, Benoit;Lamouche, Guy;
Appeared in: Review of Scientific Instruments
Publication date: Aug 2010, volume: 81, issue:8, pages: 083101 - 083101-8
Publisher: IEEE
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» Optical communications [Series Editorial]
Abstract:
In this month¿s Optical Communications Series (OCS) we have selected contributions addressing developments in optical transport networks. Despite the slow recovery in the global economy, the global demand for Internet, video, TV, and telecommunications services has been growing at a brisk pace. As evidenced by product/service announcements at major industry conferences and trade shows, global demand for communications services with high-speed transmission of IPTV, peer-to-peer video exchange, and rapidly expanding mobile traffic shifting from former 2G to 3G to 4G services has been presenting many exciting business opportunities to the global providers of optical communications services and their suppliers. As telecommunications networks develop on a global scale, it has been realized that optical communications will continue to be the sole greatest enabler of the truly broadband communications-based services in such applications as long-distance education and telemedicine.
Autors: Gebizlioglu, O.S.;Kuwahara, H.;Jain, V.;Spencer, J.;
Appeared in: IEEE Communications Magazine
Publication date: Aug 2010, volume: 48, issue:8, pages: 136 - 137
Publisher: IEEE
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» Optical Fiber Drawing Process Model Using an Analytical Neck-Down Profile
Abstract:
Numerical models play an important role in the design of the optical fiber drawing process for tailored mechanical properties and optical transmission characteristics. The rigorous part of a numerical fiber drawing model is the determination of the neck-down profile, which is calculated based on a force balance along the fiber axis, requiring intensive numerical iterations for solution. An alternative approach has been the use of an empirical neck-down profile based on experimental results; however, this approach is restricted to the simulation of the particular drawing conditions used in the experiments. This paper presents an approach to numerical simulations of an optical fiber drawing process where an analytical hyperbolic tangent function is used to describe the neck-down shape in a generalized manner, and the parameters of the function are determined based on a force balance for the drawing conditions. The physical model is based on a 2-D numerical analysis of the flow, heat, and mass transfer phenomena involved in the drawing and cooling processes during the manufacturing of optical glass fibers. The effects of fiber draw speed, maximum furnace temperature, and the furnace length on the neck-down profile are investigated and discussed in terms of the final fiber radius and the draw tension. The approach provides for computationally efficient process simulations without the need to fit the neck-down profile to experimental data.
Autors: Mawardi, A.;Pitchumani, R.;
Appeared in: IEEE Photonics Journal
Publication date: Aug 2010, volume: 2, issue:4, pages: 620 - 629
Publisher: IEEE
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» Optical Interconnect for High-End Computer Systems
Abstract:
Editor's note:Advances in silicon photonic technology have made possible the use of optical communication in large-scale chip arrays. This article shows how such a structure utilizes the high bandwidth of the optical links through optical proximity communication that enables significant levels of device integration.—Partha Pande, Washington State University
Autors: Ho, Ron;Liu, Frankie;Patil, Dinesh;Zheng, Xuezhe;Li, Guoliang;Shubin, Ivan;Alon, Elad;Lexau, Jon;Schwetman, Herb;Cunningham, John;Krishnamoorthy, Ashok V.;
Appeared in: IEEE Design & Test of Computers
Publication date: Aug 2010, volume: 27, issue:4, pages: 10 - 19
Publisher: IEEE
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» Optical Manipulation of Microparticles in an SU-8/PDMS Hybrid Microfluidic Chip Incorporating a Monolithically Integrated On-Chip Lens Set
Abstract:
An SU-8/PDMS microfluidic chip incorporating a monolithically integrated on-chip lens set for transport and manipulation of microparticles is developed. The components, including the on-chip lens set, the microfluidic channel, and the fiber grooves, are defined in a single layer of SU-8 by one-step photolithography. The design of the on-chip lens set and the fabrication of the microfluidic chip are fully described. The influence of the beam-waist radius on the manipulation performance is theoretically analyzed and experimentally verified for the first time. In the cross-type optofluidic architecture, the evaluation is performed by measuring the particle displacement with different beam-waist radii under different fluid-flow rates. The on-chip lens set is designed to have a specific dimension to achieve the required beam-waist radius. It is revealed that the particle displacement is counter-proportional to the beam-waist radius. An experiment is performed. The results show that the particle displacement is increased by reducing the beam-waist radius. The optical manipulation of microparticles is also demonstrated by using two counter-propagating light beams that are perpendicular to the fluid-flow direction with the beam-waist radius determined by two on-chip lens sets placed on the two sides of the microfluidic channel. The proposed architecture could be used to enhance the performance in particle transport, separation, and concentration.
Autors: Guo, H.;Zhao, P.;Xiao, G.;Zhang, Z.;Yao, J.;
Appeared in: IEEE Journal of Selected Topics in Quantum Electronics
Publication date: Aug 2010, volume: 16, issue:4, pages: 919 - 926
Publisher: IEEE
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» Optical Millimeter-Wave Generation and Transmission Without Carrier Suppression for Single- and Multi-Band Wireless Over Fiber Applications
Abstract:
A new optical millimeter-wave generation scheme to double the beating frequency without suppressing the carrier by taking advantages of the out-of-phase property between sidebands of a phase-modulated optical carrier is proposed for the first time. Theoretical analysis shows that the generated 60 GHz optical millimeter-wave (mm-wave) can tolerant nm wavelength drifting with filter bandwidth ranging from 70 to 100 GHz to sustain first to second harmonic suppression ratio of 18 dB. The doubled frequency is continuously tunable from 60 to 90 GHz within 100 GHz filter bandwidth with RF power variation of less than 2 dB. In addition, simultaneously generating and transmitting multi-band signal: millimeter-wave band, microwave band, and baseband leveraging the same concept is also proposed. Error-free transmission of 2.5 Gb/s wireless baseband signals carried by the generated 60 GHz mm-wave is successfully demonstrated in both single- and multi-band network environments over a combined optical fiber and wireless distance with a proper equivalent isotropically radiated power of about 20 dBm for in-building access. Moreover, dispersion effect on the generated frequency-doubled optical mm-wave is analyzed by experimentally comparing the link performance of both single mode fiber (SMF-28) and dispersion-shifted fiber cases. It is concluded that for single-band service delivery, the proposed scheme is immune to the interference from the dispersion-induced, redundant 1st harmonics; however, to deliver multi-band services, launching lightwave at zero-dispersion wavelength over SMF-28 is highly recommended to mitigate inter-band interference.
Autors: Chien, H.-C.;Hsueh, Y.-T.;Chowdhury, A.;Yu, J.;Chang, G.-K.;
Appeared in: Journal of Lightwave Technology
Publication date: Aug 2010, volume: 28, issue:16, pages: 2230 - 2237
Publisher: IEEE
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» Optical Spectroscopy to Guide Photodynamic Therapy of Head and Neck Tumors
Abstract:
In contrast to other interstitial applications of photodynamic therapy (PDT), optical guidance or monitoring in the head and neck is at a very early stage of development. The present paper reviews the use of optical approaches, in particular optical spectroscopy, that have been used or have the potential to guide the application of PDT. When considering the usefulness of these methods, it is important to consider the volume over which these measurements are acquired, the influence of differences in and changes to the background optical properties, the implications for these effects on the measured parameters and the difficulty of incorporating these types of measurements in clinical practice in head and neck PDT. To illustrate these considerations, we present an application of a recently developed technique, which we term fluorescence differential path length spectroscopy for monitoring meta-tetra(hydroxyphenyl)-chlorin or Foscan-PDT of interstitial head and neck cancer.
Autors: Robinson, D. J.;Baris Karakullukçu, M. M.;Kruijt, B. M.;Chad Kanick, S. M.;van Veen, R. P.;Amelink, A. P.;Sterenborg, H. J. C. M.;Witjes, M. J.;Bing Tan, I. I.;
Appeared in: IEEE Journal of Selected Topics in Quantum Electronics
Publication date: Aug 2010, volume: 16, issue:4, pages: 854 - 862
Publisher: IEEE
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» Optical Wireless Communication Systems in the Mb/s to Gb/s Range, Suitable for Industrial Applications
Abstract:
For future short- and mid-range industrial applications, optical wireless (OW) communication systems are expected to play a major role. When moderate transmission rates (100 Mb/s range) are required, OW communications present a viable and promising technology, supplemental to conventional radio wireless systems. Advanced approaches based on diversity techniques and adaptive signal processing show potential to achieve both high spatial coverage and high bit rates of more than 100 Mb/s. Visible-light communication systems using white phosphorescent LEDs equally present an interesting application potential, combining illumination with data transfer. When high data volumes (100 Gb/s range) need to be transmitted, tailored optical data links provide a solution of choice. Exemplarily, a scalable (24–140 Gb/s) optical data link is presented, developed for future implementation in maskless lithography systems. The link comprises a high-speed data buffer with synchronizable architecture and scalable throughput ( 24 Gb/s), an optical free-space transmission solution, and finally, a 45-channel low-noise optical receiver chip based on BiCMOS 0.6  m technology.
Autors: Paraskevopoulos , A.;Vučić, J.;Voß, S.-H.;Swoboda, R.;Langer, K.-D.;
Appeared in: IEEE/ASME Transactions on Mechatronics
Publication date: Aug 2010, volume: 15, issue:4, pages: 541 - 547
Publisher: IEEE
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» Optically Powered WDM Signal Transmission System With Distributed Parametric Amplification
Abstract:
We report, for the first time to our knowledge, an optically powered wavelength-division-multiplexing (WDM) communication system with distributed parametric amplification in the dispersion-shifted fiber. The parametric pump for the amplification of WDM signals also acts as the power supply for the receiver component. The proposed scheme is also a potential candidate for the “last mile” transmission. Successful musical signal transmission has been demonstrated. Additionally, four channels of 10-Gb/s WDM signals are used to get more precise performance evaluation of the system. The power penalties of less than or equal to 1.35 dB at a bit-error rate of are achieved for all WDM channels in the presence of 10-dB parametric gain.
Autors: Xu, X.;Cheung, K. K. Y.;Yang, S.;Liang, Y.;Yuk, T. I.;Wong, K. K. Y.;
Appeared in: IEEE Photonics Technology Letters
Publication date: Aug 2010, volume: 22, issue:16, pages: 1232 - 1234
Publisher: IEEE
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» Optimal beamforming in ultrasound using the ideal observer
Abstract:
Beamforming of received pulse-echo data generally involves the compression of signals from multiple channels within an aperture. This compression is irreversible, and therefore allows the possibility that information relevant for performing a diagnostic task is irretrievably lost. The purpose of this study was to evaluate information transfer in beamforming using a previously developed ideal observer model to quantify diagnostic information relevant to performing a task. We describe an elaborated statistical model of image formation for fixed-focus transmission and single-channel reception within a moving aperture, and we use this model on a panel of tasks related to breast sonography to evaluate receive-beamforming approaches that optimize the transfer of information. Under the assumption that acquisition noise is well described as an additive wide-band Gaussian white-noise process, we show that signal compression across receive-aperture channels after a 2-D matched-filtering operation results in no loss of diagnostic information. Across tasks, the matched-filter beamformer results in more information than standard delay-and-sum beamforming in the subsequent radio-frequency signal by a factor of two. We also show that for this matched filter, 68% of the information gain can be attributed to the phase of the matched-filter and 21% can be attributed to the amplitude. A 1-D matched filtering along axial lines shows no advantage over delay-andsum, suggesting an important role for incorporating correlations across different aperture windows in beamforming. We also show that a post-compression processing before the computation of an envelope is necessary to pass the diagnostic information in the beamformed radio-frequency signal to the final envelope image.
Autors: Abbey, C.K.;Nguyen, N.Q.;Insana, M.F.;
Appeared in: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Publication date: Aug 2010, volume: 57, issue:8, pages: 1782 - 1796
Publisher: IEEE
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» Optimal Bidding Strategies for Thermal and Generic Programming Units in the Day-Ahead Electricity Market
Abstract:
This study has developed a stochastic programming model that integrates the day-ahead optimal bidding problem with the most recent regulation rules of the Iberian Electricity Market (MIBEL) for bilateral contracts (BC), with a special consideration for the new mechanism to balance the competition of the production market, namely virtual power plant (VPP) auctions. The model allows a price-taking generation company (GenCo) to decide on the unit commitment of the thermal units, the economic dispatch of the BCs between the thermal units and the generic programming unit (GPU), and the optimal sale/purchase bids for all units (thermal and generic), by observing the MIBEL regulation. The uncertainty of the spot prices has been represented through scenario sets built from the most recent real data using scenario reduction techniques. The model has been solved using real data from a Spanish generation company and spot prices, and the results have been reported and analyzed.
Autors: Heredia, F.-J.;Rider, M. J.;Corchero, C.;
Appeared in: IEEE Transactions on Power Systems
Publication date: Aug 2010, volume: 25, issue:3, pages: 1504 - 1518
Publisher: IEEE
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» Optimal Cooperative ALOHA Multiple Access in Fading Channels
Abstract:
To enhance the system throughput in a multiple access network, we discover that cooperative multiplexing can effectively increase the system traffic. A cooperative ALOHA multiple access (CAMA) is therefore proposed to achieve the optimal system throughput in fading channels by the tradeoff between cooperative diversity and cooperative multiplexing.
Autors: Chiang, Yi-Han;Chen, Kwang-Cheng;
Appeared in: IEEE Communications Letters
Publication date: Aug 2010, volume: 14, issue:8, pages: 779 - 781
Publisher: IEEE
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» Optimal Design of Doubly Fed Induction Generators Using Field Reconstruction Method
Abstract:
Doubly fed induction generator is attracting attention among options in distributed wind energy harvest. Traditional design and analysis of doubly fed induction generator (DFIG) dominantly rely on lump-parameters and finite-element models. Although finite-element analysis (FEA) method is available, the computational time limits its application in iterative optimal design practices. This paper is based on the use of field reconstruction method (FRM) which can greatly reduce the computation cost, whereas maintaining acceptable accuracy. In order to conduct efficiency optimization, the procedure to calculate flux density and core losses are described. Finally, an optimal design method of DFIG towards maximum annual energy production in a given area with available wind speed information is presented.
Autors: Wang, W.;Kiani, M.;Fahimi, B.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Aug 2010, volume: 46, issue:8, pages: 3453 - 3456
Publisher: IEEE
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» Optimal Power Management in Fueled Systems With Finite Storage Capacity
Abstract:
Fueled power systems using secondary energy storage are analyzed. A generic model of such systems is suggested, and an optimal power management strategy that maximizes efficiency is derived analytically. The model and optimal management solution emphasizes the constraint imposed by finite storage capacity. The optimal generated energy is established independently of the system's capacity, and load, and general characteristics of it are derived and proved. The analytic solution provides an intuitive comprehension into the optimal power management, without needing numeric simulations.
Autors: Levron, Y.;Shmilovitz, D.;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Aug 2010, volume: 57, issue:8, pages: 2221 - 2231
Publisher: IEEE
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» Optimal Preventive Maintenance Scheduling in Semiconductor Manufacturing Systems: Software Tool and Simulation Case Studies
Abstract:
This paper presents the architecture and implementation of a preventive maintenance optimization software tool (PMOST), based on algorithms for the optimal scheduling of preventive maintenance (PM) tasks in semiconductor manufacturing operations. We also present results from four complex simulation case studies, based on real industrial data and employing full fab models, to illustrate the use, data needs and outcomes produced by PMOST. These results demonstrate significant improvements in tool production and consolidation of PM tasks. We give a description of the different software modules that compose PMOST, to provide guidelines as well as a template for other implementations of the PM optimization algorithms utilized by PMOST.
Autors: Ramirez-Hernandez, J. A.;Crabtree, J.;Yao, X.;Fernandez, E.;Fu, M. C.;Janakiram, M.;Marcus, S. I.;O'Connor, M.;Patel, N.;
Appeared in: IEEE Transactions on Semiconductor Manufacturing
Publication date: Aug 2010, volume: 23, issue:3, pages: 477 - 489
Publisher: IEEE
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» Optimal probing control for wireless transmission when the payload is negligible
Abstract:
A mobile electronic device needs to periodically connect to a stationary receiver, but the information to transfer is minimal. One such example is the electronic bracelet used in house arrest, where the main purpose is to inform the receiver that the person is in the house. Because the mobile device does not know its current distance from the receiver, it has incentive to first send a low-strength signal to conserve its battery energy. If the low-strength signal fails to reach the receiver, the mobile device then gradually increases its signal strength until a successful connection occurs. By formulating the problem as a dynamic program, we characterize the structure of the optimal probing policy and develop an algorithm to compute it. We also consider a discrete approximation that can be easily implemented in practice. Numerical examples show promising improvement of the derived policy over naive heuristic policies, and that the derived policy is robust when there are small errors in estimating the distribution of the distance between the mobile device and the receiver. Copyright © 2010 John Wiley & Sons, Ltd.
Autors: Kyle Y. Lin, Yu-Feng Wei
Appeared in: Optimal Control Applications and Methods
Publication date: Aug 2010
Publisher: Wiley InterScience
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» Optimal task space control design of a Stewart manipulator for aircraft stall recovery
Abstract:
This paper presents an algorithm to develop a mission-based optimal task space control for a Stewart manipulator. The proposed algorithm consists of two optimization phases. The first phase seeks an optimal polynomial approximate model for the forward kinematics of a Stewart manipulator using a predicted square error cost function. The second phase optimally tunes the controller gains in order to meet special mission requirements. Genetic algorithms are used in both phases as the optimization method. A stall recovery maneuver, one of the most dangerous flight conditions, is selected as the test case. The proposed mission-based optimal task space control shows...
Autors: Ashraf, Omran , Ayman, Kassem
Appeared in: Aerospace Science and Technology
Publication date: Aug 2010
Publisher: Elsevier B.V.
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» Optimal Variable-Weight Optical Orthogonal Codes via Difference Packings
Abstract:
Variable-weight optical orthogonal code (OOC) was introduced by Yang for multimedia optical CDMA systems with multiple quality of service (QoS) requirements. In this paper, the upper bound on the size of variable-weight OOCs is improved, a cyclic packing is introduced to construct a variable-weight OOC, an upper bound for the number of blocks of packings is obtained, and an equivalence between optimal cyclic packing and optimal variable-weight optical orthogonal code is established. Recursive constructions for optimal s are also presented. By using skew starters and these constructions, infinite classes of optimal -OOCs are obtained for , and .
Autors: Wu, D.;Zhao, H.;Fan, P.;Shinohara, S.;
Appeared in: IEEE Transactions on Information Theory
Publication date: Aug 2010, volume: 56, issue:8, pages: 4053 - 4060
Publisher: IEEE
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» Optimal Wideband Beamforming for Uniform Linear Arrays Based on Frequency-Domain MISO System Identification
Abstract:
Frequency-invariant (FI) beamforming for wideband antenna arrays inevitably involves array aperture loss at the higher-end frequencies of the bandwidth. In order to minimize aperture loss and to fully utilize the array aperture at different operation frequencies, an optimal wideband beamformer for uniform linear array (ULA) is designed based on Dolph-Chebyshev's theory of beamforming. Different from the existing FI beamformers for wideband arrays, our wideband beamformer produces frequency-dependent patterns which have the narrowest mainlobe width for any given equiripple sidelobe level over a wide frequency bandwidth. These frequency-dependent patterns are obtained through using the system identification method to determine the transfer function of the beamforming network. A matrix formulation is developed to calculate the frequency-dependent optimal Riblet-Chebyshev weights for element spacings smaller than half wavelength. The transfer function of the beamforming network, which is treated as an equivalent multi-input and single-output (MISO) system, is then obtained by the method of system identification with the optimal frequency-dependent Riblet-Chebyshev weights as the input data. Numerical results are provided to verify the effectiveness and validity of the proposed method.
Autors: Wang, B. H.;Hui, H. T.;Leong, M. S.;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Aug 2010, volume: 58, issue:8, pages: 2580 - 2587
Publisher: IEEE
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» Optimal/Near-Optimal Dimensionality Reduction for Distributed Estimation in Homogeneous and Certain Inhomogeneous Scenarios
Abstract:
We consider distributed estimation of a deterministic vector parameter from noisy sensor observations in a wireless sensor network (WSN). The observation noise is assumed uncorrelated across sensors. To meet stringent power and bandwidth budgets inherent in WSNs, local data dimensionality reduction is performed at each sensor to reduce the number of messages sent to a fusion center (FC). The problem of interest is to jointly design the compression matrices associated with those sensors, aiming at minimizing the estimation error at the FC. Such a dimensionality reduction problem is investigated in this paper. Specifically, we study a homogeneous environment where all sensors have identical noise covariance matrices and an inhomogeneous environment where the noise covariance matrices across the sensors have the same correlation structure but with different scaling factors. Given a total number of messages sent to the FC, theoretical lower bounds on the estimation error of any compression strategy are derived for both cases. Compression strategies are developed to approach or even attain the corresponding theoretical lower bounds. Performance analysis and simulations are carried out to illustrate the optimality and effectiveness of the proposed compression strategies.
Autors: Fang, J.;Li, H.;
Appeared in: IEEE Transactions on Signal Processing
Publication date: Aug 2010, volume: 58, issue:8, pages: 4339 - 4353
Publisher: IEEE
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» Optimisation of complete complementary codes in MIMO radar system
Abstract:
The novelty of multiple-input multiple-output (MIMO) radar is to improve the performance of radar utilising spatial diversity and waveform diversity. Proposed is the optimisation design of complete complementary sequence (CC-S) for MIMO radar based on channel capacity with the clutter statistical properties known. The method obtains the optimised CC-S through maximising the channel capacity of MIMO radar. The result shows that the optimised CC-S is a function of the clutter covariance matrix. Finally, the method from the information theoretical point of view is verified.
Autors: Li, S.F.;Chen, J.;Zhang, L.Q.;
Appeared in: Electronics Letters
Publication date: Aug 2010, volume: 46, issue:16, pages: 1157 - 1159
Publisher: IEEE
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» Optimisation of the deposition and annealing parameters of paraelectric PLZT () thin films grown by RF magnetron sputtering
Abstract:
Optimisation of the deposition and annealing conditions for the preparation of PLZT () thin films using RF magnetron sputtering with oxide powder targets has been studied. Good quality materials have been obtained on substrates of (0001) Al2O3, SiO2/Si and Pt/Ti/SiO2/Si. Dielectric and optical properties of the thin films were characterised. Transmission of thin films is more than 80% in the visible spectrum range.
Autors: B., Jaber , D., Rémiens , E., Cattan , B., Thierry
Appeared in: Sensors and Actuators A: Physical
Publication date: Aug 2010
Publisher: Elsevier B.V.
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» Optimization of a Parallel Shoulder Mechanism to Achieve a High-Force, Low-Mass, Robotic-Arm Exoskeleton
Abstract:
This paper describes a robotic-arm exoskeleton that uses a parallel mechanism inspired by the human forearm to allow naturalistic shoulder movements. The mechanism can produce large forces through a substantial portion of the range of motion (RoM) of the human arm while remaining lightweight. This paper describes the optimization of the exoskeleton's torque capabilities by the modification of the key geometric design parameters.
Autors: Klein, J.;Spencer, S.;Allington, J.;Bobrow, J. E.;Reinkensmeyer, D.;
Appeared in: IEEE Transactions on Robotics
Publication date: Aug 2010, volume: 26, issue:4, pages: 710 - 715
Publisher: IEEE
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» Optimization of Electromagnetic and Magnetic Shielding Using ON/OFF Method
Abstract:
The ON/OFF method which was developed for the static field problem is extended to the dynamic field problem. We applied the ON/OFF sensitivity method to the steady state linear eddy current problem in order to determine the optimal topology of the electromagnetic and magnetic shield. As a result, a surprising optimal shape of electromagnetic and magnetic shield, which we could not imagine beforehand can be obtained using the ON/OFF method. A criterion of how to choose the sensitivity with respect to the reluctivity or conductivity is discussed. It is shown that the ON/OFF method can be used for the design of electromagnetic or magnetic shielding, even when the material is the magnetic steel sheet which have two kinds of variables, magnetic permeability and conductivity. The best shielding configuration can be obtained for each frequency by adopting the result with a larger design sensitivity.
Autors: Takahashi, N.;Nakazaki, S.;Miyagi, D.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Aug 2010, volume: 46, issue:8, pages: 3153 - 3156
Publisher: IEEE
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» Optimization of Imprecise Circuits Represented by Taylor Series and Real-Valued Polynomials
Abstract:
Arithmetic circuits in general do not match specifications exactly, leading to different implementations within allowed imprecision. We present a technique to search for the least expensive fixed-point implementations for a given error bound. The method is practical in real applications and overcomes traditional precision analysis pessimism, as it allows simultaneous selection of multiple word lengths and even some function approximation, primarily based on Taylor series. Starting from real-valued representation, such as Taylor series, we rely on arithmetic transform to explore maximum imprecision by a branch-and-bound search algorithm to investigate imprecision. We also adopt a new tight-bound interval scheme, and derive a precision optimization algorithm that explores multiple precision parameters to get an implementation with smallest area cost.
Autors: Pang, Y.;Radecka, K.;Zilic, Z.;
Appeared in: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Publication date: Aug 2010, volume: 29, issue:8, pages: 1177 - 1190
Publisher: IEEE
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» Optimization of Inductors Using Evolutionary Algorithms and Its Experimental Validation
Abstract:
This paper presents parameter and topology optimization of inductor shapes using evolutionary algorithms. The goal of the optimization is to reduce the size of inductors satisfying the specifications on inductance values under weak and strong bias–current conditions. The inductance values are computed from the finite-element (FE) method taking magnetic saturation into account. The result of the parameter optimization, which leads to significant reduction in the volume, is realized for test, and the dependence of inductance on bias currents is experimentally measured, which is shown to agree well with the computed values. Moreover, novel methods are introduced for topology optimization to obtain inductor shapes with homogeneous ferrite cores suitable for mass production.
Autors: Watanabe, K.;Campelo, F.;Iijima, Y.;Kawano, K.;Matsuo, T.;Mifune, T.;Igarashi, H.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Aug 2010, volume: 46, issue:8, pages: 3393 - 3396
Publisher: IEEE
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» Optimized fusion of heterogeneous wireless networks based on media-independent handover operations [Accepted from Open Call]
Abstract:
In recent years a plethora of wireless technologies has become available. Users may efficiently utilize heterogeneous network infrastructures while moving among different access networks in order to attain better services, everywhere and at any time, following the always best connected concept. In this article enhanced handover functionality is described for integrated Wi-Fi/WiMAX networks, based on the recently established IEEE 802.21 standard that serves to glue together heterogeneous wireless access technologies. Moreover, alternative implementation choices are introduced with an emphasis on the mapping of primitives between the IEEE 802.21 standard and the various underlying access network technologies. As a result, optimized media-independent handover operations are provided alongside highlighted possible improvements to the related standards.
Autors: Lampropoulos, G.;Skianis, C.;Neves, P.;
Appeared in: IEEE Wireless Communications
Publication date: Aug 2010, volume: 17, issue:4, pages: 78 - 87
Publisher: IEEE
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» Optimizing focused ion beam created solid immersion lenses in bulk silicon using design of experiments
Abstract:
In search of efficient solutions improving image resolution for backside failure analysis, the creation of solid immersion lenses in bulk silicon using focused ion beam has been investigated deeply in parametric detail. This technique is optimized using design of experiments, providing a better understanding of the pure ion beam sputtering process. It produces SILs in less than 20min of processing time and offers an additional magnification of 3.2×. The optimal setup of this FIB created SIL is demonstrated and provides an improvement in resolution by a factor of 1.8. Limits of this technique are encountered and analyzed for future development.
Autors: P., Scholz , C., Gallrapp , U., Kerst , T., Lundquist , C., Boit
Appeared in: Microelectronics Reliability
Publication date: Aug 2010
Publisher: Elsevier B.V.
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» Optimizing Plasmonic Grating Sensors for Limit of Detection Based on a Cramer–Rao Bound
Abstract:
We explore the impact of the geometrical features such as the period, duty cycle, and thickness on the performance of a metal-dielectric plasmonic grating sensor. The sensor is designed to operate at the wavelength of 850 nm for water-monitoring applications. Limit of detection (LOD) is chosen as the performance metric for the optimization of the sensor design. The LOD metric is based on a Cramer-Rao bound (CRB) and offers a theoretical lower limit on the estimation uncertainty of the spectral shift in the proposed sensor. We show that the lowest values of LOD correspond to grating designs, which result in step-like spectral features. An optimum grating design corresponds to gold stripes that are 160 nm thick and 456 nm wide on glass where the stripes are separated by 74 nm. Although our study is focused on a particular design and application, our methods and observations are applicable to a wide range of plasmonic grating sensor designs.
Autors: Karbasivalashani, S.;Mafi, A.;
Appeared in: IEEE Photonics Journal
Publication date: Aug 2010, volume: 2, issue:4, pages: 543 - 552
Publisher: IEEE
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» Optimum Design of Polymeric Thermal Microactuator With Embedded Silicon Skeleton
Abstract:
An SU-8 polymeric actuator with an embedded silicon skeleton has recently been reported to have good actuation performance. As a composite, it has room for performance improvements by design. Yet, it has not been optimized for the best performance. In this paper, we perform a parametric study, based on analytical and finite-element models, to find the optimum design. Properties and actuation capabilities are related to design parameters of the composite. In a design case to maximize work density, the parametric study found an optimum design consisting of 70% SU-8 and 30% Si. As compared with pure SU-8, the optimum composite design has a Young's modulus that is 2.2 times higher, a thermal stress that is 2.5 times higher, a work density that is 2.6 times higher, a coefficient of thermal expansion that is 5% higher, and a shorter thermal-response time. The optimum design can deliver a maximum strain of 2.77% and a maximum stress of 196 MPa at the maximum operating temperature of 200 . Moreover, it has a rather high work density of 2.71 , which is comparable with other thermal phase-change actuators. In conclusion, this polymeric composite actuator is very powerful for microactuation. [2009-0295]
Autors: Lau, G.-K.;Goosen, J. F. L.;van Keulen, F.;
Appeared in: Journal of Microelectromechanical Systems
Publication date: Aug 2010, volume: 19, issue:4, pages: 992 - 1001
Publisher: IEEE
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» Orientation Modulation for Data Hiding in Clustered-Dot Halftone Prints
Abstract:
We present a new framework for data hiding in images printed with clustered dot halftones. Our application scenario, like other hardcopy embedding methods, encounters fundamental challenges due to extreme bilevel quantization inherent in halftoning, the stringent requirements of image fidelity, and other unavoidable printing and scanning distortions. To overcome these challenges, while still allowing for automated extraction of the embedded data and a high embedding capacity, we propose a number of innovations. First, we perform the embedding jointly with the halftoning by employing an analytical halftone threshold function that allows steering of the halftone spot orientation within each halftone cell based upon embedded data. In this process, image fidelity is emphasized and, if necessary, the capability to recover individual data values is sacrificed resulting in unavoidable erasures and errors. To overcome these and other sources of errors, we propose a suitable data detection and error control methodology based upon a statistical representation for the print-scan channel that effectively models the channel dependence upon the cover image gray-level. To combat the geometric distortion inherent in the print-scan process, we exploit the periodic halftone structure to recover from global scaling and rotation and propose a novel decision directed synchronization technique that counters locally varying printing distortion. Experimental results demonstrate the power of the proposed framework: we achieve high operational rates while preserving halftone image quality.
Autors: Bulan, O.;Sharma, G.;Monga, V.;
Appeared in: IEEE Transactions on Image Processing
Publication date: Aug 2010, volume: 19, issue:8, pages: 2070 - 2084
Publisher: IEEE
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» Orthogonal frequency division multiple access PON (OFDMA-PON) for colorless upstream transmission beyond 10 Gb/s
Abstract:
In this paper, we overview the fundamental principles of next-generation optical Orthogonal Frequency Division Multiple Access (OFDMA)-PON systems, with a particular focus on upstream architectures capable of achieving 10+Gb/s colorless upstream transmission. We also propose a novel OFDMA-PON architecture that satisfies these requirements and is capable of exceeding 10 Gb/s upstream transmission over a single wavelength. It is first analytically shown that optical carrier suppression at the optical network units (ONUs) combined with coherent detection at the optical line terminal (OLT) successfully eliminates both in- and cross-polarization beating noise that would otherwise be generated at the OLT and would fundamentally limit upstream transmission performance. A centralized light source OFDM-based PON architecture with source-free ONUs and OLTside coherent detection is then presented and experimentally verified to achieve 20 Gb/s/λ transmission over a class B+ optical distribution network (20 km SSMF with an additional 1:32 optical split.) By thus providing very high-speed, flexible, colorless upstream transmission, the proposed architecture is an attractive candidate for next-generation PON systems capable of cost-efficiently delivering heterogeneous services.
Autors: Cvijetic, N.;Qian, D.;Hu, J.;Wang, T.;
Appeared in: IEEE Journal on Selected Areas in Communications
Publication date: Aug 2010, volume: 28, issue:6, pages: 781 - 790
Publisher: IEEE
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» Outage analysis of relay-assisted free-space optical communications
Abstract:
Despite their attractive features, free-space optical (FSO) communications suffer from several challenges in practical deployment; the major of them is fading or scintillation. To overcome such limitations, multiple input multiple output (MIMO) and cooperative techniques have been proposed. Although the promising effects of cooperative transmissions in radio frequency (RF) communications have greatly been investigated, there have not been remarkable researches on cooperative transmissions in FSO communications. In this study, the authors consider a relay-assisted FSO communication and investigate the outage performance of two well-known cooperative protocols, namely amplify-and-forward (AF) and decodeand- forward (DF), for this communication system. By a new definition of the order of diversity, the authors derive an analytical expression for the performance comparison of different cooperative and non-cooperative protocols. The authors also evaluate the performance of a FSO communication with two transmitter telescopes (MIMO systems) and compare its outage probability with those of cooperation strategies. The authors investigate the best place for the relay for both the AF and DF strategies and show that relay-assisted techniques can be used for FSO communication to achieve spatial diversity. Their performance can surpass that of the two-transmitter case by properly choosing the location of the relay.
Autors: Karim, M.;Nasiri-Kenari, I.M.;
Appeared in: IET Communications
Publication date: Aug 2010, volume: 4, issue:12, pages: 1423 - 1432
Publisher: IEEE
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» Outage Probability Analysis of Cognitive Transmissions: Impact of Spectrum Sensing Overhead
Abstract:
In cognitive radio networks, a cognitive source node requires two essential phases to complete a cognitive transmission process: the phase of spectrum sensing with a certain time duration (also referred to as spectrum sensing overhead) to detect a spectrum hole and the phase of data transmission through the detected spectrum hole. In this paper, we focus on the outage probability analysis of cognitive transmissions by considering the two phases jointly to examine the impact of spectrum sensing overhead on system performance. A closed-form expression of an overall outage probability that accounts for both the probability of no spectrum hole detected and the probability of a channel outage is derived for cognitive transmissions over Rayleigh fading channels. We further conduct an asymptotic outage analysis in high signal-to-noise ratio regions and obtain an optimal spectrum sensing overhead solution to minimize the asymptotic outage probability. Besides, numerical results show that a minimized overall outage probability can be achieved through a tradeoff in determining the time durations for the spectrum hole detection and data transmission phases. In this paper, we also investigate the use of cognitive relay to improve the outage performance of cognitive transmissions. We show that a significant improvement is achieved by the proposed cognitive relay scheme in terms of the overall outage probability.
Autors: Zou, Yulong;Yao, Yu-Dong;Zheng, Baoyu;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Aug 2010, volume: 9, issue:8, pages: 2676 - 2688
Publisher: IEEE
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» Outage Probability Due to PMD in Coherent PDM QPSK Systems With Electronic Equalization
Abstract:
Polarization-division-multiplexed (PDM) quadrature phase-shift-keying (QPSK) coherent optical systems employ blind adaptive electronic equalizers for polarization-mode dispersion compensation. In this letter, we compare the performance of fractionally spaced, linear electronic equalizers, composed of four parallel finite impulse response (FIR) filters of various lengths, using the outage probability as a performance criterion. The constant modulus algorithm is applied for the adaptation of FIR filter coefficients. A parallel programming implementation of the multicanonical Monte Carlo method is adopted for the estimation of the tails of the outage probability distribution. It is shown that less than 20 complex, half-symbol-period-spaced taps per FIR filter suffice, in order to reduce the outage probability of PDM QPSK coherent optical systems to less than , for a mean differential group delay up to twice the symbol period.
Autors: Mantzoukis, N. C.;Petrou, C. S.;Vgenis, A.;Kamalakis, T.;Roudas, I.;Raptis, L.;
Appeared in: IEEE Photonics Technology Letters
Publication date: Aug 2010, volume: 22, issue:16, pages: 1247 - 1249
Publisher: IEEE
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» Output feedback model predictive control of uncertain norm-bounded linear systems
Abstract:
A constrained output feedback model predictive control (MPC) scheme for uncertain Norm-Bounded discrete-time linear systems is presented. This scheme extends recent results achieved by the authors under full-state availability to the more interesting case of incomplete and noisy state information. The design procedure consists of an off-line step where a state feedback and an asymptotic observer (dynamic primal controller) are designed via bilinear matrix inequalities and used to robustly stabilize a suitably augmented state plant. The on-line moving horizon procedure adds N free control moves to the action of the primal controller which are computed by solving a linear matrix inequality optimization problem whose numerical complexity grows up only linearly with the control horizon N. The effectiveness of the proposed MPC strategy is illustrated by a numerical example. Copyright © 2010 John Wiley & Sons, Ltd.
Autors: D. Famularo, G. Franzè
Appeared in: International Journal of Robust and Nonlinear Control
Publication date: Aug 2010
Publisher: Wiley InterScience
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» Overlapping Finite Elements for Arbitrary Surfaces in 3-D
Abstract:
Overlapping elements have previously been employed to connect two surfaces or subdomains meshed separately. This method has been developed in 2-D and in 3-D for plane surfaces. The paper extends the overlapping method to arbitrary non-planar surfaces; this is accomplished by introducing new shape functions. The proposed method can be applied to account for movement without any undesirable distortion of the mesh. Two examples are presented to show the effectiveness of the new method.
Autors: Krebs, G.;Clenet , S.;Tsukerman, I.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Aug 2010, volume: 46, issue:8, pages: 3473 - 3476
Publisher: IEEE
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» Oxide HDP-CVD Modeling for Shallow Trench Isolation
Abstract:
A method is proposed to model the high-density plasma chemical vapor deposition step within the shallow trench isolation module in the CMOS technology. To model a process is the first step in the design of a run-to-run system in order to reduce the lot-to-lot variability (a lot equals 25 wafers). A model is developed to control the MeanThickness and the Range of the MeanThickness (uniformity). A satisfactory model was obtained through a design of experiments.
Autors: Roussy, A.;Delachet, L.;Belharet, D.;Pinaton, J.;Collot, P.;
Appeared in: IEEE Transactions on Semiconductor Manufacturing
Publication date: Aug 2010, volume: 23, issue:3, pages: 400 - 410
Publisher: IEEE
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» Oxygen doping of P3HT:PCBM blends: Influence on trap states, charge carrier mobility and solar cell performance
Abstract:
We investigated the influence of oxygen on the performance of P3HT:PCBM (poly(3-hexylthiophene):[6,6]-phenyl C61 butyric acid methyl ester) solar cells by current-voltage, thermally stimulated current (TSC) and charge extraction by linearly increasing voltage (CELIV) measurement techniques. The exposure to oxygen leads to an enhanced charge carrier concentration and a decreased charge carrier mobility. Further, an enhanced formation of deeper traps was observed, although the overall density of traps was found to be unaffected upon oxygen exposure. With the aid of macroscopic simulations, based on solving the differential equation system of Poisson, continuity and drift-diffusion equations in one dimension, we demonstrate the...
Autors: Julia, Schafferhans , Andreas, Baumann , Alexander, Wagenpfahl , Carsten, Deibel , Vladimir, Dyakonov
Appeared in: Organic Electronics
Publication date: Aug 2010
Publisher: Elsevier B.V.
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» P-Channel Nonvolatile Flash Memory With a Dopant-Segregated Schottky-Barrier Source/Drain
Abstract:
A p-channel dopant-segregated-Schottky-barrier (DSSB) device based on a SOI FinFET structure is proposed for silicon-oxide-nitride-oxide-silicon type Flash memory, providing the feasibility of bit-by-bit operation through the aid of a symmetric program/erase operation. This concept is based on utilizing injected holes due to enhanced Fowler–Nordheim tunneling probability triggered by the sharpened energy band bending at the DSSB source/drain junctions as a programming method and the tunneled electrons from a silicon channel as an erasing method. As a result, a threshold voltage window of nearly 4 V and good data retention are achieved within a P/E time of 3.2 .
Autors: Choi, S.-J.;Han, J.-W.;Moon, D.-I.;Kim, S.;Jang, M.;Choi, Y.-K.;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Aug 2010, volume: 57, issue:8, pages: 1737 - 1742
Publisher: IEEE
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» Pairwise Intersession Network Coding on Directed Networks
Abstract:
When there exists only a single multicast session in a directed acyclic/cyclic network, the existence of a network coding solution is characterized by the classic min-cut/max-flow theorem. For the case of more than one coexisting sessions, network coding also demonstrates throughput improvement over noncoded solutions. This paper proposes pairwise intersession network coding, which allows for arbitrary directed networks but restricts the coding operations to being between two symbols (for acyclic networks) or between two strings of symbols (for cyclic networks). A graph-theoretic characterization of pairwise intersession network coding is proven based on paths with controlled edge-overlap. This new characterization generalizes the edge-disjoint path characterization of noncoded network communication and includes the well-studied butterfly graph as a special case. Based on this new characterization, various aspects of pairwise intersession network coding are studied, including the sufficiency of linear codes, the complexity of identifying coding opportunities, its topological analysis, and bandwidth- and coding-efficiency.
Autors: Wang, C.-C.;Shroff, N. B.;
Appeared in: IEEE Transactions on Information Theory
Publication date: Aug 2010, volume: 56, issue:8, pages: 3879 - 3900
Publisher: IEEE
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» Papers to be Published in Future Issues of IEEE Transactions on Engineering Management
Abstract:
Autors: , .;
Appeared in: IEEE Transactions on Engineering Management
Publication date: Aug 2010, volume: 57, issue:3, pages: 528 - 529
Publisher: IEEE
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» Parallel Computing of Magnetic Field for Rotating Machines on the Earth Simulator
Abstract:
We developed a parallel computing method of the magnetic field for rotating machines by using the 3-D finite element method (FEM) with edge elements. In this paper, we describe the outline of the developed method and an optimization of the method for the Earth simulator, which is a vector-type parallel supercomputer in Japan. Moreover, the performance of the proposed method running on the Earth simulator is quantitatively clarified.
Autors: Nakano, T.;Kawase, Y.;Yamaguchi, T.;Nakamura, M.;Nishikawa, N.;Uehara, H.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Aug 2010, volume: 46, issue:8, pages: 3273 - 3276
Publisher: IEEE
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» Parallel Direct Solver for the Finite Integration Technique in Electrokinetic Problems
Abstract:
The finite integration technique allows the simulation of real-world electromagnetic field problems with complex geometries. It provides a discrete reformulation of Maxwell's equations in their integral form suitable for numerical computing. The resulting matrix equations of the discretized fields can be used for efficient numerical simulations on modern computers and can be exploited to use a parallel computing. In fact, by reordering the unknowns by the nested dissection method, it is possible to directly construct the lower triangular matrix of the Cholesky factorization with many processors without assembling the matrix system. In this paper, a parallel algorithm is proposed for the direct solution of large sparse linear systems with the finite integration technique. This direct solver has the advantage of handling singularities in the matrix of linear systems. The computational effort for these linear systems, often encountered in numerical simulation of electromagnetic phenomena by finite integration technique, is very significant in terms of run-time and memory requirements. Many numerical tests have been carried out to evaluate the performance of the parallel direct solver.
Autors: Tinzefte, A.;Le Menach, Y.;Korecki, J.;Guyomarch, F.;Piriou, F.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Aug 2010, volume: 46, issue:8, pages: 3269 - 3272
Publisher: IEEE
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» Parallel-RC Feedback Low-Noise Amplifier for UWB Applications
Abstract:
A two-stage 3.1- to 10.6-GHz ultrawideband CMOS low-noise amplifier (LNA) is presented. In our design, a parallel resistance–capacitance shunt feedback with a source inductance is proposed to obtain broadband input matching and to reduce the noise level effectively; furthermore, a parallel inductance–capacitance network at drain is drawn to further suppress the noise, and a very low noise level is achieved. The proposed LNA is implemented by the Taiwan Semiconductor Manufacturing Company 0.18- CMOS technology. Measured results show that the noise figure is 2.5–4.7 dB from 3.1 to 10.6 GHz, which may be the best result among previous reports in the 0.18- CMOS 3.1- to 10.6-GHz ultrawideband LNA. The power gain is 10.9–13.9 dB from 3.1 to 10.6 GHz. The input return loss is below 9.4 dB from 3.1 to 15 GHz. It consumes 14.4 mW from a 1.4-V supply voltage and occupies an area of only 0.46 .
Autors: He, K.-C.;Li, M.-T.;Li, C.-M.;Tarng, J.-H.;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Aug 2010, volume: 57, issue:8, pages: 582 - 586
Publisher: IEEE
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» Parallelization methods for implementation of discharge simulation along resin insulator surfaces?
Abstract:
In this paper, we will investigate the implementation of the parallelization approaches used in the program of discharge simulation along resin insulator surfaces in SF6/N2 gas mixture which initially consumes a great deal of computational time. In a general way, this simulation program spent 10 days of execution to achieve satisfactory research results. For this reason, the goal of our paper is to reduce the execution time by parallelizing this program. Three parallelization approaches were used in our simulation: (i) splitting by different types of the charged particles using a distributed-memory approach, (ii) splitting by physical domain using a distributed-memory...
Autors: Kenli, Li , Tianfang, Tan , Xiaoyong, Tang , Feng, Wang
Appeared in: Computers & Electrical Engineering
Publication date: Aug 2010
Publisher: Elsevier B.V.
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