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Power flow optimization using positive quadratic programming *

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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WEC prototype advancement with consideration of a real-time damage accumulation algorithm

WEC prototype advancement with consideration of a real-time ...

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2011 IEEE PES Trondheim PowerTech: The Power of Technology for a Sustainable Society, POWERTECH 2011

作者： Stillinger, Chad J. Brekken, Ted K. A. Von Jouanne, Annette Paasch, Robert Naviaux, David Rhinefrank, Ken Prudell, Joseph Schacher, Al Hammagren, Erik IEEE United States Department of Energy Systems Oregon State University Corvallis OR United States United States School of Electrical Engineering and Computer Science Oregon State University United States Department of Mechanical Design School of Mechanical Industrial and Manufacturing Engineering Oregon State University United States Northwest National Marine Renewable Energy Center United States

ISBN: (纸本)9781424484195

Machine maintenance and repair is not a trivial issue when it comes to renewable energy devices. It has been said that one of the most important factors in enhancing the marketability of wind energy is to cut its overall maintenance costs, which is about 10% - 20% of the overall cost of energy [1]. The average maintenance and repair costs of ocean wave energy devices are yet to be determined, but it may be higher than wind energy. The harsh ocean environment, repeated cycling of the drive train, coastal storms, environmental concerns, loss of revenue due to long periods of machine downtime, safety issues concerning technicians working on the buoy while it's still in operation, and so forth, all add to the maintenance and repair costs of a WEC (Wave Energy Converter). This study proposes a unique damage accumulation prediction algorithm that enables real-time determination of bearing fatigue life. © 2011 IEEE.

关键词： Wind power

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Enhanced DHCP for the fast retrieval of the spectrum map for white space applications

Enhanced DHCP for the fast retrieval of the spectrum map for...

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IEEE Conference on Wireless Communications and Networking

作者： Seungil Yoon Kyutae Lim Jongman Kim Georgia Electronic Design Center School of Electrical and Computer Engineering Georgia Institute of Technology Atlanta GA USA KORUS Research Center of Informersive Systems School of Electrical and Computer Engineering Georgia Institute of Technology Atlanta GA USA

As white space, unused local TV spectrum, will be allowed for the broadband Internet access, we can use white space network as the supplementary network of licensed and/or unlicensed access networks such as cellular and WiFi™ networks. Thus, after setting up the connection over a cellular or WiFi™ system, mobile devices equipped with a white space interface will connect to a radio resource management server to retrieve a location-based list of open white space channels, “a so-called spectrum map”. This paper aims to reduce a signaling overhead for the setup of a cellular or WiFi™ connection and the retrieval of the spectrum map. To achieve the goal, we suggest embedding the retrieval operations of the spectrum map inside the Dynamic Host Configuration Protocol (DHCP) operations for the IP assignment during the connection setup of the cellular or WiFi™ networks. The theoretical analysis demonstrates that our proposal, the fast provision of the spectrum map, can contribute to accommodating one or more white space devices when the total number of open white space channels is 30.

关键词： Servers White spaces Proposals IP networks IEEE 802.11 Standards Sensors Resource management

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Structural and Ferroelectric Properties of Large c/a Phase Bismuth Ferrite Thin Films Prepared by Ion Beam Sputtering

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MRS Online Proceedings Library 2011年第1期1292卷 3-8页

作者： Seiji Nakashima Yosuke Tsujita Hironori Fujisawa Jung Min Park Takeshi Kanashima Masanori Okuyama Masaru Shimizu Depattment of Electrical Engineering and Computer Sciences Graduate School of Engineering University of Hyogo Himeji Hyogo Japan Department of Systems Innovation Graduate School of Engineering Science Osaka University Toyonaka Osaka Japan Institute for NanoScience Design Osaka University Toyonaka Osaka Japan

BiFeO3 (BFO) thin films have been deposited on SrRuO3/SrTiO3 (001) substrate by using ion beam sputtering process. At low oxygen partial pressure of 11 m Pa, rhombohedral and largec/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 largec/a phase BFO werea = 0.381 nm andc = 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.

关键词： ion-beam processing ferroelectric thin film

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