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Antennas and Propagation Society International symposium

作者： S.K. Smith J.C. Bregains K.L. Melde F. Ares Dept. of ECE University of Arizona Tucson AZ USA Dept. of Applied Physics University of Santiago de Compostela Santiago de Compostela Spain

Array distributions that have a uniformly excited central segment and a monotonically decreasing outer segment have been shown to yield low sidelobe patterns with specified constraints on the effective radiated voltage (ERV). An analytical method has been previously presented for generating these distributions using a constrained least squares (CLS) method, given constraints on both the peak amplitude of the elements and the ERV. Simulated annealing (SA) is a versatile global optimization technique that has been effectively used for a wide variety of array applications. In this paper, we compare the results obtained from generating radiation patterns for linear arrays with high aperture efficiency and low sidelobes using the CLS method and SA optimization.

关键词： Optimization methods Cost function Least squares methods Simulated annealing Physics Voltage Surfaces Apertures Lighting Distributed computing

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Intelligent systems integration for data acquisition and modeling of coastal ecosystems 2004

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proceedings of the 17th international conference on Innovations in applied artificial intelligence

作者： Carl Steidley Alexey Sadovski Ray Bachnak Department of Computing and Mathematical Sciences Texas A&M University TX

ISBN: (纸本)9783540220077

In this paper, we describe the primary data acquisition system for environmental modeling efforts at Texas A&M University-Corpus Christi. Additionally, we describe the design and development issues encountered in the production of two supplemental data acquisition systems. Finally, we present examples of the use of the acquired data for water level prediction modeling efforts.

关键词： intelligent interfaces

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Application of intelligent information retrieval techniques to a television similar program guide 2004

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proceedings of the 17th international conference on Innovations in applied artificial intelligence

作者： Chandrashekar Machiraju Sirisha Kanda Venu Dasigi School of Computing and Software Engineering Southern Polytechnic State University Marietta Georgia School of Computing and Software Engineering Southern Polytechnic State University Marietta Georgia

ISBN: (纸本)9783540220077

The advent of Digital Television and the "Connected Home" has led to an information overload to the viewer. A lot of research has been conducted towards developing interactive program guide services and products that attempt to simplify the television viewing experience. Closed captions that are part of the transmission signal of the programs aired have been identified as a good source of information [1]. Information Retrieval techniques may be applied to closed caption transcripts to create applications such as the one we describe here, called the "Similar Program Guide (SPG)". Such a guide would notify the user of programs being aired on other channels, similar to the one he/she is currently watching or similar to the ones in the user's profile. Additionally, this guide would allow users to compile their favorite programs and thus maintain user profiles. In this paper we discuss the approaches for development of the application. We use Information Retrieval techniques as the basis for this application.

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Parallel implementation of a Lagrangian stochastic model for pollution dispersion

Parallel implementation of a Lagrangian stochastic model for...

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International symposium on Computer Architecture and High Performance computing (SBAC-PAD)

作者： D.R. Roberti R.P. Souto H.F. de Campos Velho G.A. Degrazia D. Anfossi Department of Physics Federal University of Santa Maria Santa Maria Rio Grande do Sul Brazil Laboratory for Computing and Applied Mathematics (LAC) National Institute of Space Research (INPE) Sao Paulo Brazil Institute of Atmospheric Sciences and Climate (ISAC) Italian National Council of Research Italy

Pollutant dispersion models in the atmosphere can describe by Eulerian or Lagrangian approaches. Lagrangian models belong to the class of Monte Carlo methods. This type of method is very flexible, solving more complex problems, however this computational cost is greater than Eulerian models, as it is well established in the atmospheric pollutant and nuclear engineering communities. A parallel version of the Lagrangian particle model - LAMBDA - is developed using the MPI message passing communication library. Performance tests were executed in a distributed memory parallel machine, a multicomputer based on IA-32 architecture. Portions of the pollutant in the air are considered particles emitted from a pollutant source, evolving under stochastic forcing. This yields independent evolution equations for each particle of the model that can be executed by a different processor in a parallel implementation. Speed-up results show that the parallel implementation is suitable for the used architecture.

关键词： Lagrangian functions Stochastic processes Atmospheric modeling Air pollution Atmosphere Computational efficiency Message passing Libraries Testing Parallel machines

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System Identification of an Open-Frame ROV Using a Low-Cost Inertial Measurement Unit

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IFAC proceedings Volumes 2004年第14期37卷 157-162页

作者： Nathan W.A. Sowerby Geoff N. Roberts Gurvinder S. Baicher Mechatronics Research Centre School of Computing and Engineering University of Wales Newport South Wales UK

This paper investigates the experimental setup and signal procesing and estimation techniques required to identify a model of an open-frame Remotely Operated Vehicle (ROV) using a low-cost Inertial Measurement Unit (IMU). A low-cost IMU that has been used to gauge the motion of all six degrees of freedom of the ROV is described. A new type of perturbation signal is introduced that has a waveform shown to successfully train universal approximators and that will persistently excite the dynamics while keeping the vehicle within the boundaries of a testing tank. A unique signal is applied to each thruster of a commercially available Seaeye Falcon ROV and a least squares estimation framework is introduced to remove the noise from the IMU.

关键词： Perturbation theory MEMS Inertial measurement Signal estimation

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Routing with confidence: supporting discretionary routing requirements in policy based networks

Routing with confidence: supporting discretionary routing re...

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International Workshop on Policies for Distributed Systems and Networks

作者： Apu Kapadia Prasad Naldurg R.H. Campbell Department of Computer Science University of Illinois Urbana-Champaign Urbana-Champaign IL USA U.S. Department of Energy USA

We propose a novel policy-based secure routing framework that extends the mandatory nature of network access-control policies and allows users to exercise discretionary control on what routes they choose in a given network. In contrast to existing research that focuses mainly on restricting network access based on user credentials, we present a model that allows users to specify discretionary constraints on path characteristics and discover routes based on situational trust attributes of routers in a network. In this context, we present three levels of trust-attribute certification based on inherent, consensus based, and inferred characteristics of routers. We also define a "confidence" measure that captures the "quality of protection" of a route with regard to various dynamic trust relationships that arise from this interaction between user preferences and network policy. Based on this measure, we show how to generate paths of highest confidence efficiently by using shortest path algorithms. We show how our model generalizes the notion of quality of protection (QoP) for secure routing and discuss how it can be applied to anonymous and privacy-aware routing, intrusion tolerant communication, and secure resource discovery for ubiquitous computing, high performance, and peer-to-peer environments.

关键词： Routing Intelligent networks Traffic control Laboratories Communication system traffic control Computer science Protection Access control Certification Ubiquitous computing

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Agent-oriented software analysis

Agent-oriented software analysis

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Australian Conference on Software Engineering

作者： K. Chan L. Sterling S. Karunasekera University of Melbourne Australia

Agent-oriented software engineering (AOSE) has become an active area of research in recent years. We look at the use of agent-oriented concepts for software analysis. Using agent-oriented analysis may offer benefits even if the system is implemented without an agent-based language or framework (e.g. using an object-oriented detailed design and language). We examine the software analysis components of a number of existing agent-oriented methodologies. We discuss the benefits that can be gained by using agent-oriented concepts, and where the concepts require further development. Based on this analysis, we present the agent-oriented methodology that we are developing, and describe an example of how it may be applied for software analysis.

关键词： Object oriented modeling Software engineering Application software Programming Buildings Information analysis Humans Data analysis Software systems Data flow computing

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A new borrow-and-return model for broadcasting videos with low user delay

A new borrow-and-return model for broadcasting videos with l...

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IEEE International Conference on Networks

作者： S.A. Azad M. Murshed Gippsland School of Computing and IT Monash University Churchill VIC Australia

Broadcasting is an efficient method of video transmission but it imposes a user delay. This user delay can be reduced effectively without increasing the number of channels by lending the free time slots of the videos without viewers to those videos with viewers to speed up the latter's transmission. This technique can be applied to those broadcasting protocols that broadcast the first segment on the first channel. This borrow-and-return technique uses unutilized bandwidth of some videos to reduce other's user delay. This paper proposes an improvement over existing borrow-and-return model, which makes even more efficient use of borrowed bandwidth. The new model reduces the user delay further by eliminating premature transmission of video data in the "return" phase.

关键词： Broadcasting Videos Multimedia communication Bandwidth Streaming media Delay effects Multicast protocols Australia Unicast Scalability

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Effect of selection heuristics on routing and wavelength assignment using greedy EDP algorithm

Effect of selection heuristics on routing and wavelength ass...

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IEEE International Conference on Networks

作者： P. Manohar V. Sridhar Applied Research Group Satyam Computer Services Limited Bangalore India

Routing and wavelength assignment (RWA) problem in wavelength routed optical networks is known to be NP-complete. Problems of routing and wavelength assignment have been individually solved using techniques such as integer programming which are complex and computationally expensive. RWA with greedy maximum edge disjoint path (EDP) algorithm solves routing and wavelength assignment problems simultaneously and is shown to be as good as previously known solution methods. In this paper, we study effect of selection heuristics, for a lightpath to be routed and a route assigned to it, in this greedy EDP for RWA. Then, we present their comparative performances using parameters such as number of wavelengths required to satisfy a given set of lightpaths and blocking probability in case of limited wavelengths.

关键词： Wavelength routing Wavelength assignment Network topology Optical fiber networks Graph theory Computer networks Optical computing Electronic mail Linear programming Optical wavelength conversion

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Analytical Method for computing Controller Gains of a Satellite Launcher

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IFAC proceedings Volumes 2004年第6期37卷 1019-1023页

作者： D. Carmona W.C. Leite Filho lnstituto Nacional de Pesquisas Espaciais-INPE Instituto de Aeromiutica e Esparço-IAE

Satellite launchers are time-variant systems and, consequently, the frozen poles technique is applied, analyzing the plant inside some time interval where it can be considered invariant. The pole placement using the LQR method demonstrates nonsatisfactory time response and has a poor link between the weighting matrixes and the transitory response. An analytical method is proposed, so that the controUer gains are computed focusing time requirements as rise and settling time and ramp input error. This method allows the designer to be able to specify directly these characteristics; as a result, the poles/zeros are free to move regarding the transitory response.

关键词： attitude control LQR control method PID control

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