91 research outputs found

    The Application of Evolutionary Algorithms for Energy Efficient Grooming of Scheduled Sub-Wavelength Traffic Demands in Optical Networks

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    In recent years there has been a growing recognition of the need for developing energy efficient network design approaches for WDM backbone networks as well. The typical approach has been to switch off some components such as line cards and router ports during low demand periods, and has focussed on traditional static and dynamic traffic models. In this paper, we present a new approach that exploits knowledge of demand holding times to intelligently share resources among non-overlapping demands and reduce the overall power consumption of the network. We consider the fixed-window scheduled traffic model (STM), and present i) a Genetic Algorithm (GA) and ii) a Memetic Algorithm (MA) based strategy that jointly minimizes both power consumption and transceiver cost for the logical topology. Simulation results clearly demonstrate that both of the proposed algorithms outperform traditional holding time unaware (HTU) approaches; the GA leads to additional improvements even compared to the shortest path holding time aware (HTA) heuristic. However, the MA manages to achieve similar results to the GA while taking up 4 to 5 times less computational resources and time to compute

    Improving the Performance of SDM-EON Through Demand Prioritization: A Comprehensive Analysis

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    This paper studies the impact of demand-prioritization on Space-Division Multiplexing Elastic Optical Networks (SDM-EON). For this purpose, we solve the static Routing, Modulation Level, Spatial Mode, and Spectrum Assignment (RMLSSA) problem using 34 different explainable demand-prioritization strategies. Although previous works have applied heuristics or meta-heuristics to perform demand-prioritization, they have not focused on identifying the best prioritization strategies, their inner operation, and the implications behind their good performance by thorough profiling and impact analysis. We focus on a comprehensive analysis identifying the best explainable strategies to sort network demands in SDM-EON, considering the physical-layer impairments found in optical communications. Also, we show that simply using the common shortest path routing might lead to higher resource requirements. Extensive simulation results show that up to 8.33% capacity savings can be achieved on average by balanced routing, up to a 16.69% capacity savings can be achieved using the best performing demand-prioritization strategy compared to the worst-performing ones, the most used demand-prioritization strategy in the literature (serving demands with higher bandwidth requirements first) is not the best-performing one but the one sorting based on the path lengths, and using double-criteria strategies to break ties is key for a good performance. These results are relevant showing that a good combination of routing and demand-prioritization heuristics impact significantly on network performance. Additionally, they increase the understanding about the inner workings of good heuristics, a valuable knowledge when network settings forbid using more computationally complex approaches

    VLSI Design

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    This book provides some recent advances in design nanometer VLSI chips. The selected topics try to present some open problems and challenges with important topics ranging from design tools, new post-silicon devices, GPU-based parallel computing, emerging 3D integration, and antenna design. The book consists of two parts, with chapters such as: VLSI design for multi-sensor smart systems on a chip, Three-dimensional integrated circuits design for thousand-core processors, Parallel symbolic analysis of large analog circuits on GPU platforms, Algorithms for CAD tools VLSI design, A multilevel memetic algorithm for large SAT-encoded problems, etc

    Parallel memetic algorithms for the problem of workforce distribution in dynamis multi-agent system

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    Tesis inédita de la Universidad Complutense de Madrid, Facultad de Informática, Departamento de Arquitectura de Computadores y Automática, leída el 20/09/2013Esta tesis describe un novedoso enfoque para resolver el problema de distribución de carga de trabajo en sistemas multi-agente dinámicos basados en arquitecturas de pizarra, enfocándose especialmente en un escenario real: el call center multitarea. Para abordar este tipo de entornos dinámicos, tradicionalmente se han aplicado diversas heurísticas voraces que permiten dar una solución en tiempo real. Básicamente, dichas heurísticas realizan planificaciones continuamente, considerando el estado del sistema en cada momento. Como las decisiones se toman de forma voraz sin hacer una planificación óptima, la distribución de la carga de trabajo puede ser pobre a medio y/o largo plazo. El uso de algoritmos meméticos paralelos nos puede permitir encontrar soluciones mucho más precisas. Para aplicar este tipo de algoritmos, introducimos el concepto de ventana temporal adaptativa. De esta forma, el tamaño de la ventana temporal depende del nivel de dinamismo del sistema en un instante dado. Este trabajo propone una serie de herramientas para determinar el dinamismo del sistema de forma automática, así como un novedoso módulo de predicción basado en una red neuronal y un potente método de búsqueda basado en meta-algoritmos meméticos paralelos para poder lidiar con entornos dinámicos complejos. Para concluir, comparamos nuestro enfoque con otras técnicas del estado del arte en un entorno de producción real (Telefónica) obteniendo mejores resultados que el resto de técnicas actuales. También se proporciona un estudio exhaustivo de cada uno de los módulos.Depto. de Arquitectura de Computadores y AutomáticaFac. de InformáticaTRUEunpu

    A Brief Analysis of Gravitational Search Algorithm (GSA) Publication from 2009 to May 2013

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    Gravitational Search Algorithm was introduced in year 2009. Since its introduction, the academic community shows a great interest on this algorith. This can be seen by the high number of publications with a short span of time. This paper analyses the publication trend of Gravitational Search Algorithm since its introduction until May 2013. The objective of this paper is to give exposure to reader the publication trend in the area of Gravitational Search Algorithm

    Telecommunications Networks

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    This book guides readers through the basics of rapidly emerging networks to more advanced concepts and future expectations of Telecommunications Networks. It identifies and examines the most pressing research issues in Telecommunications and it contains chapters written by leading researchers, academics and industry professionals. Telecommunications Networks - Current Status and Future Trends covers surveys of recent publications that investigate key areas of interest such as: IMS, eTOM, 3G/4G, optimization problems, modeling, simulation, quality of service, etc. This book, that is suitable for both PhD and master students, is organized into six sections: New Generation Networks, Quality of Services, Sensor Networks, Telecommunications, Traffic Engineering and Routing
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