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IEEE Power and Energy Society General Meeting

作者： Somayeh Sojoudi Steven H. Low Department of Control and Dynamical Systems California Institute of Technology Computer Science and Electrical Engineering Departments California Institute of Technology

ISBN: (纸本)9781457710001

Plug-in hybrid electric vehicles (PHEVs) play an important role in making a greener future. Given a group of PHEVs distributed across a power network equipped with the smart grid technology (e.g. wireless communication devices), the objective of this paper is to study how to schedule the charging of the PHEV batteries. To this end, we assume that each battery must be fully charged by a pre-specified time, and that the charging rate can be time-varying at discrete-time instants. The scheduling problem for the PHEV charging can be augmented into the optimal power flow (OPF) problem to obtain a joint OPF-charging (dynamic) optimization. A solution to this highly nonconvex problem optimizes the network performance by minimizing the generation and charging costs while satisfying the network, physical and inelastic-load constraints. A global optimum to the joint OPF-charging optimization can be found efficiently in polynomial time by solving its convex dual problem whenever the duality gap is zero for the joint OPF-charging problem. It is shown in a recent work that the duality gap is expected to be zero for the classical OPF problem. We build on this result and prove that the duality gap is zero for the joint OPF-charging optimization if it is zero for the classical OPF problem. The results of this work are applied to the IEEE 14 bus system.

关键词： Smart grids optimal charging charging Polynomial time Power grids CHARGING(ACCOUNTTNG) Zero Joints Joints charging rate Batteries Hybrid electric vehicles

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Cooperative inter-vehicular communications in highway traffic

Cooperative inter-vehicular communications in highway traffi...

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Canadian Conference on electrical and computer engineering (CCECE)

作者： Mohamed Fathy Feteiha Murat Uysal Abdul Rahim Ahmad Department of Electrical and Computer Engineering University of Waterloo Waterloo Ontario Canada Department of Systems Design Engineering University of Waterloo Waterloo Ontario Canada

In this paper, we investigate the performance of a single relay assisted cooperative vehicular network in a highway traffic scenario. Source and relaying vehicles are assumed to be traveling in the same direction with similar speeds. This results in a relative velocity nearly equal to zero and leads to a frequency-flat and time-flat fading in source-to relay link. On the other hand, source-to-destination and relay to-destination links are modeled as doubly-selective fading. To handle spreading in time and frequency, we propose a precoded cooperative scheme to exploit delay and Doppler spreads to our advantage. Under the assumption of amplify-and-forward relaying with orthogonal cooperation protocol, we derive a pairwise error probability expression and demonstrate the achievable diversity gains. We further conduct Monte Carlo simulations to confirm the analytical derivations and present the error rate performance of the proposed scheme with imperfect channel estimation.

关键词： Vehicles Fading Relays Time frequency analysis Diversity methods Signal to noise ratio Bit error rate

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Spatial-and-Temporal-Weighted Structure from Motion

Spatial-and-Temporal-Weighted Structure from Motion

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Canadian Conference on computer and Robot Vision, CRV

作者： Guanghui Wang John S. Zelek Q.M. Jonathan Wu Department of Systems Design Engineering University of Waterloo Waterloo ONT Canada Department of Electrical and Computer Engineering University of Waterloo Waterloo ONT Canada

The paper focuses on the problem of structure from motion and proposes a spatial-and-temporal-weighted factorization algorithm. The contributions of the paper are as follows: First, it is demonstrated that the image reprojection error is generally in proportion to the error magnitude contained in the image. Second, the error distribution contained in the measurement matrix is modelled spatially and temporally from the image reprojection residuals. Third, based on the estimated error distribution, a spatial-and-temporal-weighted factorization algorithm is proposed to handle the uncertainty caused by significant image noises. Compared with existing approaches, the proposed technique does not require a prior information of image measurement, and it is easy to implement. Extensive experiments on synthetic data and real images are performed to validate the proposed method.

关键词： Noise Uncertainty Shape Tracking Matrix decomposition Cameras Robustness

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Power flow optimization using positive quadratic programming *

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IFAC Proceedings Volumes 2011年第1期44卷 10481-10486页

作者： Javad Lavei Anders Rantzer Stephen Low Department of Control and Dynamical Systems Caltech Automatic Control LTH Lund University Sweden Steven H. Low is with the Computer Science and Electrical Engineering Departments Caltech

Abstract The problem to minimize power losses in an electrical network subject to voltage and power constraints is in general hard to solve. However, it has recently been discovered that semidefinite programming relaxations in many cases enable exact computation of the global optimum. Here we point out a fundamental reason for the successful relaxations, namely that the passive network components give rise to matrices with nonnegative offdiagonal entries. Recent progress on quadratic programming with Metzler matrix structure can therefore be applied.

关键词： Power flow optimization relaxation analysis

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Application of the amplification matrix latency insertion method to circuits with dependent sources

Application of the amplification matrix latency insertion me...

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electrical design of Advanced Packaging and systems Symposium, EDAPS

作者： Ping Liu Jilin Tan Zhongyong Zhou José Schutt-Ainé Patrick Goh Cadence Design Systems Inc. USA Department of Electrical and Computer Engineering University of Illinois Urbana-Champaign USA

This paper applies the amplification matrix latency insertion method (LIM) to the circuits including dependent sources. The formulation derivation for the general circuits and the stability conditions of the amplification matrix LIM are presented in detail. Compared with the conventional scalar LIM, the amplification matrix LIM need much larger time step, so it can dramatically improve the performance. The simulation results validate the conclusion.

关键词： Voltage control Equations Mathematical model Stability analysis Eigenvalues and eigenfunctions Circuit stability Integrated circuit modeling

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Multi-resolution level set image segmentation using wavelets

Multi-resolution level set image segmentation using wavelets

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IEEE International Conference on Image Processing

作者： Fares S. Al-Qunaieer Hamid R. Tizhoosh Shahryar Rahnamayan Systems Design Engineering University of Waterloo Waterloo ONT Canada Electrical and Computer Engineering University of Ontario Institute of Technology (UOIT) Oshawa ONT Canada

Level set methods have been used for image segmentation. Because partial deferential equations are solved to propagate a curve, level-set image segmentation has a slow convergence speed. The objective of this paper is to propose a method that increases the convergence speed. The proposed approach exploits the benefit of multi-resolutional analysis. Wavelet transform is used to decompose the image into different resolutions. The obtained results show a great improvement in terms of speed and accuracy.

关键词： Level set Image segmentation Image resolution Active contours Accuracy Image edge detection

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Effect of buffers on stability of Internet congestion controllers

Effect of buffers on stability of Internet congestion contro...

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IEEE Annual Joint Conference: INFOCOM, IEEE computer and Communications Societies

作者： Somayeh Sojoudi Steven H. Low John C. Doyle Department of Control and Dynamical Systems California Institute of Technology USA Computer Science and Electrical Engineering Departments California Institute of Technology USA

Almost all existing fluid models of congestion control assume that the fluid flow at the output of a link is the same as the fluid flow at the input of the link. This means that all links in the path of a flow see the original source rate. In reality, a fluid flow is modified by the queueing processes on its path, so that an intermediate link will generally not see the original source rate. In this paper, we propose a simple model that explicitly takes into account of the effect of buffering on output flows. We study the dual and primal-dual algorithms that use implicit feedback and show that, while they are always asymptotically stable if feedback delay is ignored, they can be unstable in the new model.

关键词： Heuristic algorithms Equations Delay Stability analysis Asymptotic stability Aggregates Internet

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Functional Framework and Hardware Platform for Dependability Study in Short Range Wireless Embedded systems

Functional Framework and Hardware Platform for Dependability...

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IEEE International Mixed-Signals, Sensors, and systems Test Workshop, IMS3TW

作者： Benaouneur Senouci Anne-Johan Annema Mark Bentum Hans G. Kerkhoff Telecommunication Engineering Group Computer Architecture for Embedded Systems Group Electrical Engineering Mathematics and Computer Science Faculty University of Twente Enschede Netherlands Integrated Circuit Design Group Electrical Engineering Mathematics and Computer Science Faculty University of Twente Enschede Netherlands Telecommunication Engineering Group University of Twente Enschede Netherlands Computer Architecture for Embedded Systems Group Electrical Engineering Mathematics and Computer Science Faculty University of Twente Enschede Netherlands

A new direction in short-range wireless applications has appeared in the form of high-speed data communication devices for distances of a few meters. Behind these embedded applications, a complex Hardware/Software architecture is built. Dependability is one of the major challenges in these systems. Obviously in such systems, the attribute reliability has to be investigated for various components and at different abstractions levels. This paper presents a hardware platform for wireless system dependability analysis as an alternative for the time consuming global system simulation technique. The platform is built using several instances of one of the commercial FPGA platforms available on the market place. Based on this platform we introduce a new methodology and a flow to investigate the different parts of system dependability at different abstraction levels. The benefits to use the proposed methodology are two fold: first it takes care of the whole system (HW/SW part, mixed RF and wireless part) and second, the hardware platform enables to explore the application's reliability under real environmental conditions in order to study the effect of the environment threats on the system.

关键词： Wireless communication Hardware Reliability System-on-a-chip computer architecture Libraries Embedded systems

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Structural and ferroelectric properties of large c/a phase bismuth ferrite thin films prepared by ion beam sputtering

Structural and ferroelectric properties of large c/a phase b...

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2010 MRS Fall Meeting

作者： Nakashima, Seiji Tsujita, Yosuke Fujisawa, Hironori Park, Jung Min Kanashima, Takeshi Okuyama, Masanori Shimizu, Masaru Depattment of Electrical Engineering and Computer Sciences Graduate School of Engineering University of Hyogo 2167 Shosya Himeji Hyogo 671-2280 Japan Department of Systems Innovation Graduate School of Engineering Science Osaka University 1-3 Machikaneyama-cho Toyonaka Osaka 560-8531 Japan Institute for NanoScience Design Osaka University 1-3 Machikaneyama-cho Toyonaka Osaka 560-8531 Japan

ISBN: (纸本)9781605112695

BiFeO3 (BFO) thin films have been deposited on SrRuO 3/SrTiO3 (001) substrate by using ion beam sputtering process. At low oxygen partial pressure of 11 m Pa, rhombohedral and large c/a mixed phase thin film have been obtained in spite of rhombohedral BFO single phase formation at high oxygen partial pressure of 73 mPa. From wide area 2θ-ψ mappings, diffraction peaks from large c/a phase BFO thin film were obtained with the same extinction rule as those of rhombohedral BFO. Reciprocal space mappings around BFO (003) and BFO (103) spots indicate that lattice parameters of large c/a phase BFO were a = 0.381 nm and c = 0.461 nm (c/a = 1.22), respectively. Moreover ferroelectric domain switching could be observed in both of rhombohedral BFO and mixed phase BFO thin films. © 2011 Materials Research Society.

关键词： Strontium compounds

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Partitioned latency insertion method (PLIM) with stability considerations

Partitioned latency insertion method (PLIM) with stability c...

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IEEE Workshop on Signal Propagation on Interconnects (SPI)

作者： Patrick Goh José E. Schutt-Ainé Dmitri Klokotov Jilin Tan Ping Liu Wenliang Dai Feras Al-Hawari Department of Electrical and Computer Engineering University of Illinois Urbana-Champaign Urbana IL USA Cadence Design Systems Chelmsford MA USA

In this paper, we present a modular approach to the high frequency simulation of large networks by utilizing the latency insertion method (LIM) and considering the stability criteria of partitions of different latencies in the circuit. This results in a robust algorithm that is able to preserve the stability condition while improving the runtime of the overall transient simulation. An extension to the LIM to handle dependent sources is also presented, along with a generalized stability criteria for selecting a maximum stable time step.

关键词： Integrated circuit modeling Niobium RLC circuits Stability criteria Topology Equations

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