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2012 20th International Conference on Software, Telecommunications and computer Networks, SoftCOM 2012

作者： Misiunas, Nicholas Raspopovic, Miroslava Thompson, Charles Chandra, Kavitha Center for Advanced Computation and Telecommunications Department of Electrical and Computer Engineering University of Massachusetts Lowell Lowell MA 01854 United States Faculty of Information Technology Belgrade Metropolitan University Belgrade Serbia

ISBN: (纸本)9789532900347

The problem of sharing radio spectrum is analyzed using a multiple server queueing model which represents channels owned by primary users and allowed opportunistic access by a secondary user group. The primary users are constrained to occupy a group of adjacent channels for wideband transmission, whereas the secondary users utilize a single channel for narrowband transmission. The blocking performance of wideband and narrowband users are compared under two policies of channel allocation among the primary and secondary users. These policies differentiate the performance based on allocation of non-overlapping and overlapping blocks of contiguous channels to the wideband and narrowband users. The influence of the number of excess channels that can only be utilized by secondary users is also presented. A computational model developed to estimate the blocking probabilities of NB and WB users is shown to be expressed as a function of the offered loads (ρN, ρw) and the ratio of the service rates (μW/ μN). The performance impact of providing WB users a block of adjacent channels instead of distributing the requirement across the group of available channels is analyzed. The adjacency constraint will in general decrease the channel availability of WB users, but can improve the probability of channel allocation to NB users. The proposed scheme allows estimation of feasible operating regions of ρN, given a WB group size and ρw. © 2012 University of Split.

关键词： Blocking probability

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Ship tracking control based on linear active disturbance rejection control

Ship tracking control based on linear active disturbance rej...

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2012 3rd International Conference on Intelligent control and Information Processing, ICICIP 2012

作者： Li, Ronghui Li, Tieshan Zheng, Qinling Li, Qiang Navigaion College Dalian Maritime University Dalian China Center for Advanced Control Technologies Department of Electrical Computer Engineering Cleveland State University Cleveland OH United States

ISBN: (纸本)9781457721427

Owing to ship's high inertia, strong time lag, non-linearity and under-actuated characteristics, as well as sustaining external disturbances frequently, designing a high performance ship tracking controller is still one of the most important research topics of ship motion control. Active Disturbance Rejection control (ADRC) is proved to be very effective control method because it is independent of mathematical model of the plant and can compensate the internal and external disturbances dynamically. This paper investigates the applications of ADRC in ship motion tracking control and presents the design method of ADRC controller appropriate for ship tracking control. Firstly, ship motion mathematical model is introduced briefly and the linear ADRC (LADRC) is analyzed. Then considering the nonlinear ship track design model as a third order plant after utilizing variable substitution, a LADRC controller is designed by using fourth order linear extended state observer (LESO). At last, the simulation is performed. Simulation results show that the controller has a good tracking performance and disturbance rejection ability and is robust to the ship motion nonlinear characteristic and the external disturbances. The tracking process is fast, smooth and minor energy consumption. © 2012 IEEE.

关键词： controllers

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A spectrum sensing and transmission model for secondary users in cognitive radios

A spectrum sensing and transmission model for secondary user...

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International Conference on Software, Telecommunications and computer Networks (SoftCOM)

作者： Pratik Gandhi Ibrahim Alshawabkeh Kavitha Chandra Charles Thompson Center for Advanced Computation and Telecommunications Department of Electrical and Computer Engineering University of Massachusetts Lowell Lowell MA USA

An analysis of spectrum sensing and transmission of a secondary user sharing a channel with a licensed primary user is presented. The primary user access patterns are modeled as an on-off Markov process. A five state Markov model is derived to describe the performance of a secondary user that aims to utilize the channel during its idle state. Assuming perfect knowledge of the primary user access patterns, the model is analyzed with respect to the size of a back-off counter chosen when the channel is sensed busy and the size of the window allocated for secondary transmission when the channel is sensed idle. An analytical region is derived for the secondary users to operate in while the primary channel is free.

关键词： Sensors Markov processes Analytical models Cognitive radio Throughput Simulation computational modeling

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Interfaces of nested Web application framework as reusable software component

Interfaces of nested Web application framework as reusable s...

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Proceedings of the International Convention MIPRO

作者： S. Prstačić M. Žagar K. Kroflin Information Support Center Faculty of Electrical Engineering and Computing Zagreb Croatia Department of Control and Computer Engineering Faculty of Electrical Engineering and Computing Zagreb Croatia

The framework is designed to provide a simple and powerful way of Web application component development. Components of the framework can nest, and the framework is designed to be easy to reuse as a component, thus providing its components to be used by the host application. We explain the interfaces required to make this possible - what they provide, what issues they solve, and how their requirement was discovered. We also identify shortcomings of this approach, and issues that will be addressed by future work.

关键词： Blogs Abstracts Software Context Permission HTML Software engineering

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Distributed Network Size Estimation and Average Degree Estimation and control in Networks Isomorphic to Directed Graphs

Distributed Network Size Estimation and Average Degree Estim...

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Annual Allerton Conference on Communication, control, and Computing

作者： Iman Shames Themistoklis Charalambous Christoforos N. Hadjicostis Mikael Johansson Department of Electrical and Electronic Engineering University of Melbourne Automatic Control Lab Electrical Engineering Department and ACCESS Linnaeus Center Royal Institute of Technology (KTH) Department of Electrical and Computer Engineering at the University of Cyprus

ISBN: (纸本)9781467345378

Many properties of interest in graph structures are based on the nodes' average degree (i.e., the average number of edges incident to/from each node). In this work, we present asynchronous distributed algorithms, based on ratio consensus, that can be used to accurately estimate the number of nodes in a multi-component system whose communication topology is described by a directed graph. In addition, we describe an asynchronous distributed algorithm that allows each node to introduce or terminate links in order to reach a target average degree in the network. Such an approach can be useful in many realistic scenarios;for example, for the introduction and removal of renewable energy resources in a power network, while maintaining an average degree that fulfils some structural and dynamical properties and/or optimises some performance indicators of the network. The effectiveness of the proposed algorithms is demonstrated via illustrative examples.

关键词： distributed algorithms directed graphs Power grids performance indicators DISTRIBUTED NETWORKS Renewable energy resources Line of nodes Structural Elements (Construction) Ganglia Isomorphic Standing Orders Asynchronous

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Adversarial detection as a zero-sum game

Adversarial detection as a zero-sum game

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IEEE Conference on Decision and control

作者： K. G. Vamvoudakis J. P. Hespanha B. Sinopoli Y. Mo Center for Control Dynamical-systems and Computation (CCDC) University of California Santa Barbara CA USA Electrical and Computer Engineering Department Carnegie Mellon University Pittsburgh PA USA

ISBN: (纸本)9781467320658

We propose a new game theoretic approach to estimate a binary random variable based on a vector of sensor measurements that may be corrupted by an adversary. The problem is formulated as a zero-sum partial information game in which a detector attempts to minimize the probability of error and an attacker attempts to maximize this probability. Explicit mixed policies are computed using the matrix form of the game and exploiting sensor symmetry to reduce complexity and find closed-form solutions.

关键词： Games Estimation Detectors Game theory Vectors Random variables Complexity theory

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Stabilization of linear systems with distributed input delay and input saturation

Stabilization of linear systems with distributed input delay...

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作者： Zhou, Bin Gao, Huijun Lin, Zongli Duan, Guang-Ren Center for Control Theory and Guidance Technology Harbin Institute of Technology Harbin 150001 China Research Institute of Intelligent Control and Systems Harbin Institute of Technology Harbin 150001 China Charles L. Brown Department of Electrical and Computer Engineering University of Virginia Charlottesville VA 22904-4743 United States

This paper is concerned with stabilization of a linear system with distributed input delay and input saturation. Both constant and time-varying delays are considered. In the case that the input delay is constant, under the stabilizability assumption on an auxiliary system, it is shown that the system can be stabilized by state feedback for an arbitrarily large delay as long as the open-loop system is not exponentially unstable. In the case that the input delay is time-varying, but bounded, it is shown that the system can be stabilized by state feedback if the non-asymptotically stable poles of the open-loop system are all located at the origin. In both cases, stabilizing controllers are explicitly constructed by utilizing the parametric Lyapunov equation based low gain design approach we recently developed. It is also shown that in the presence of actuator saturation and under the same assumptions on the system, these controllers achieve semi-global stabilization. Some discussions on the assumptions we impose on the system are given. A numerical example illustrates the effectiveness of the proposed stabilization approach. © 2012 Elsevier Ltd. All rights reserved.

关键词： Stabilization

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Polyp Detection in Wireless Capsule Endoscopy Images by Using Region-Based Active Contour Model

Polyp Detection in Wireless Capsule Endoscopy Images by Usin...

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Iranian Conference of Biomedical engineering

作者： Hoda Eskandari Mahdi Alizadeh Alireza Talebpour Hamid Soltanian-Zadeh Department of Radiation Medicine Engineering Shahid Beheshti University Control and Intelligent Processing Center of Excellence (CIPE) School of Electrical and Computer Engineering University of Tehran

ISBN: (纸本)9781467331289

Wireless Capsule Endoscopy (WCE) is an almost new technology to capture images from the whole of Gastrointestinal (GI) tract, noninvasively. WCE is a very useful technology to detect various abnormalities like blood based abnormalities, ulcers and polyps. We note that polyps are growing tissues occur on the surface of tissue instead of inside an organ. Most polyps are not cancerous but if one becomes larger than a centimeter, it can turn into cancer by great chance. So, one of the most important advantages of WCE can be the early detection of polyps and cancers. In this paper we proposed using region-based Active Contour Method (ACM) and geometric feature for automatic detection of polyps. The results on a set of images show that the proposed method can achieve %90.91 accuracy, %100 sensitivity and %-83.33 specificity on our data set.

关键词： Polyp Wireless Capsule Endoscopy Active Countor Method

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Increasing Entanglement Monotones by Separable Operations

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Physical Review Letters 2012年第24期108卷 240504-240504页

作者： Eric Chitambar Wei Cui Hoi-Kwong Lo Center for Quantum Information and Quantum Control (CQIQC) Department of Physics and Department of Electrical and Computer Engineering University of Toronto Toronto Ontario M5S 3G4 Canada

Quantum entanglement is fundamentally related to the operational setting of local quantum operations and classical communication (LOCC). A more general class of operations known as separable operations (SEP) is often employed to approximate LOCC, but the exact difference between LOCC and SEP is unknown. In this letter, we compare the two classes in performing particular tripartite to bipartite entanglement conversions and report a gap as large as 12.5% between SEP and LOCC, which is the first known appreciable gap between the classes. Our results rely on constructing a computable entanglement monotone with a clear operational meaning that, unlike all other such monotones previously studied, is not monotonic under SEP. Finally, we prove the curious fact that convergent sequences of LOCC protocols need not be LOCC feasible in the limit.

关键词： MONOTONE operators SEPARABLE algebras QUANTUM entanglement MATHEMATICAL proofs SEQUENCES (Mathematics) STOCHASTIC convergence

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Entanglement monotones for W-type states

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Physical Review A 2012年第6期85卷 062316-062316页

作者： Eric Chitambar Wei Cui Hoi-Kwong Lo []Center for Quantum Information and Quantum Control (CQIQC) Department of Physics and Department of Electrical & Computer Engineering University of Toronto Toronto Ontario M5S 3G4 Canada

In this article, we extend recent results concerning random-pair Einstein-Podolsky-Rosen distillation and the operational gap between separable operations (SEPs) and local operations with classical communication (LOCC). In particular, we consider the problem of obtaining bipartite maximal entanglement from an N-qubit W-class state (i.e., that of the form x0|00⋯0〉+x1|10⋯0〉+⋯+xn|00⋯1〉) when the target pairs are a priori unspecified. We show that when x0=0, the optimal probabilities for SEPs can be computed using semidefinite programming. On the other hand, to bound the optimal probabilities achievable by LOCC, we introduce entanglement monotones defined on the N-qubit W class of states. The LOCC monotones we construct can be increased by SEPs, and in terms of transformation success probability, we are able to quantify a gap as large as 37% between the two classes. Additionally, we demonstrate transformations ρ⊗n→σ⊗n that are feasible by SEP for any n but impossible by LOCC.

关键词： Probability

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