937 resultados para parallel computer systems


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Abstract. The use of artificial immune systems in intrusion detection is an appealing concept for two reasons. Firstly, the human immune system provides the human body with a high level of protection from invading pathogens, in a robust, self-organised and distributed manner. Secondly, current techniques used in computer security are not able to cope with the dynamic and increasingly complex nature of computer systems and their security. It is hoped that biologically inspired approaches in this area, including the use of immune-based systems will be able to meet this challenge. Here we collate the algorithms used, the development of the systems and the outcome of their implementation. It provides an introduction and review of the key developments within this field, in addition to making suggestions for future research.

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The use of artificial immune systems in intrusion detection is an appealing concept for two reasons. Firstly, the human immune system provides the human body with a high level of protection from invading pathogens, in a robust, self-organised and distributed manner. Secondly, current techniques used in computer security are not able to cope with the dynamic and increasingly complex nature of computer systems and their security. It is hoped that biologically inspired approaches in this area, including the use of immune-based systems will be able to meet this challenge. Here we review the algorithms used, the development of the systems and the outcome of their implementation. We provide an introduction and analysis of the key developments within this field, in addition to making suggestions for future research.

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This document presents GEmSysC, an unified cryptographic API for embedded systems. Software layers implementing this API can be built over existing libraries, allowing embedded software to access cryptographic functions in a consistent way that does not depend on the underlying library. The API complies to good practices for API design and good practices for embedded software development and took its inspiration from other cryptographic libraries and standards. The main inspiration for creating GEmSysC was the CMSIS-RTOS standard, which defines an unified API for embedded software in an implementation-independent way, but targets operating systems instead of cryptographic functions. GEmSysC is made of a generic core and attachable modules, one for each cryptographic algorithm. This document contains the specification of the core of GEmSysC and three of its modules: AES, RSA and SHA-256. GEmSysC was built targeting embedded systems, but this does not restrict its use only in such systems – after all, embedded systems are just very limited computing devices. As a proof of concept, two implementations of GEmSysC were made. One of them was built over wolfSSL, which is an open source library for embedded systems. The other was built over OpenSSL, which is open source and a de facto standard. Unlike wolfSSL, OpenSSL does not specifically target embedded systems. The implementation built over wolfSSL was evaluated in a Cortex- M3 processor with no operating system while the implementation built over OpenSSL was evaluated on a personal computer with Windows 10 operating system. This document displays test results showing GEmSysC to be simpler than other libraries in some aspects. These results have shown that both implementations incur in little overhead in computation time compared to the cryptographic libraries themselves. The overhead of the implementation has been measured for each cryptographic algorithm and is between around 0% and 0.17% for the implementation over wolfSSL and between 0.03% and 1.40% for the one over OpenSSL. This document also presents the memory costs for each implementation.

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La complejidad de los sistemas actuales de computación ha obligado a los diseñadores de herramientas CAD/CAE a acondicionar lenguajes de alto nivel, tipo C++, para la descripción y automatización de estructuras algorítmicas a sus correspondientes diseños a nivel físico. Los proyectos a realizar se encuadran dentro de una línea de trabajo consistente en estudiar la programación, funcionamiento de los lenguajes SystemC y SystemVerilog, sus herramientas asociadas y analizar cómo se adecuan a las restricciones temporales y físicas de los componentes (librerías, IP's, macro-celdas, etc) para su directa implementación. En una primera fase, y para este TFG, se estudiarán los componentes que conforman el framework elegido que es SystemC y su inclusión en herramientas de diseño arquitectural. Este conocimiento nos ayudará a entender el funcionamiento y capacidad de dicha herramienta y proceder a su correcto manejo. Analizaremos y estudiaremos unos de los lenguajes de alto nivel de los que hace uso dicha herramienta. Una vez entendido el contexto de aplicación, sus restricciones y sus elementos, diseñaremos una estructura hardware. Una vez que se tenga el diseño, se procederá a su implementación haciendo uso, si es necesario, de simuladores. El proyecto finalizará con una definición de un conjunto de pruebas con el fin de verificar y validar la usabilidad y viabilidad de nuestra estructura hardware propuesta.

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Network Intrusion Detection Systems (NIDS) are computer systems which monitor a network with the aim of discerning malicious from benign activity on that network. While a wide range of approaches have met varying levels of success, most IDSs rely on having access to a database of known attack signatures which are written by security experts. Nowadays, in order to solve problems with false positive alerts, correlation algorithms are used to add additional structure to sequences of IDS alerts. However, such techniques are of no help in discovering novel attacks or variations of known attacks, something the human immune system (HIS) is capable of doing in its own specialised domain. This paper presents a novel immune algorithm for application to the IDS problem. The goal is to discover packets containing novel variations of attacks covered by an existing signature base.

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Réalisé en cotutelle avec l'École normale supérieure de Cachan – Université Paris-Saclay

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El vertiginoso crecimiento de los centros urbanos, las tecnologías emergentes y la demanda de nuevos servicios por parte de la población plantea encaminar esfuerzos hacia el desarrollo de las ciudades inteligentes. Éste concepto ha tomado fuerza entre los sectores político, económico, social, académico, ambiental y civil; de forma paralela, se han generado iniciativas que conducen hacia la integración de la infraestructura, la tecnología y los servicios para los ciudadanos. En éste contexto, una de las problemáticas con mayor impacto en la sociedad es la seguridad vial. Es necesario contar con mecanismos que disminuyan la accidentalidad, mejoren la atención a incidentes, optimicen la movilidad urbana y planeación municipal, ayuden a reducir el consumo de combustible y la emisión de gases de efecto de invernadero, así como ofrecer información dinámica y efectiva a los viajeros. En este artículo se describen dos (2) enfoques que contribuyen de manera eficiente dicho problema: los videojuegos como juegos serios y los sistemas de transporte inteligente. Ambos enfoques están encaminados a evitar colisiones y su diseño e implementación requieren componentes altamente tecnológicos (e.g. sistemas telemáticos e informáticos, inteligencia artificial, procesamiento de imágenes y modelado 3D).

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Coral Hipermercado GO es una empresa dedicada a la comercialización de diversos productos de consumo masivo. Debido a la demanda que mantienen y el nivel de transacciones que realizan en ventas diariamente,

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En el área de Aerofotogrametría Digital, el software comercial prevalente para postproceso presenta limitaciones debido a dos factores: (i) las legislaciones de cada país o región requieren diferentes convenciones, y (ii) las necesidades de las empresas son tan cambiantes que no justifican la compra de software de alto rendimiento, que puede quedar sin utilizar debido a un viraje del mercado -- El presente proyecto se ha desarrollado para atender necesidades de procesamiento automático de planos (partición, detección y corrección de errores, etc.), así como módulos de importación – exportación paquete a paquete, trazado de rutas e interacción con GPS -- Este artículo informa de los dos últimos aspectos -- Debido a necesidades de los clientes, los archivos entregados deben llevar un formato comercial (DWG, DXF), pero el procesamiento de los archivos debe ser hecho en paquetes y formatos diversos (DGN) -- Por lo tanto, fue necesario diseñar e implementar un formato acompañante que permitió llevar la información que se pierde al usar filtros comerciales (DGN a DXF/DWG) -- Asimismo se crearon módulos de importación y exportación redundantes, que hicieron efectivos dichos atributos -- En el aspecto de generación de rutas de vuelo, se reportan en este artículo la aplicación de algoritmos tradicionales de barrido (peinado) de áreas 2D, a los cuales se agregaron restricciones geométricas (puntos fijos, offsets, orden de los barridos de acuerdo a coordenadas del sitio de partida, etc.) -- Debido a los altos costos de equipos equivalentes, se decidió desarrollar software para traducción de rutas entre formatos GPS y formatos geográficos locales al país -- Ello permite la eliminación de fuentes de error y además facilita la carga del plan de vuelo, a costos mucho menores a los del hardware / software comercial

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Semantics, knowledge and Grids represent three spaces where people interact, understand, learn and create. Grids represent the advanced cyber-infrastructures and evolution. Big data influence the evolution of semantics, knowledge and Grids. Exploring semantics, knowledge and Grids on big data helps accelerate the shift of scientific paradigm, the fourth industrial revolution, and the transformational innovation of technologies.

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In a general purpose cloud system efficiencies are yet to be had from supporting diverse applications and their requirements within a storage system used for a private cloud. Supporting such diverse requirements poses a significant challenge in a storage system that supports fine grained configuration on a variety of parameters. This paper uses the Ceph distributed file system, and in particular its global parameters, to show how a single changed parameter can effect the performance for a range of access patterns when tested with an OpenStack cloud system.

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A evolução tecnológica tem provocado uma evolução na medicina, através de sistemas computacionais voltados para o armazenamento, captura e disponibilização de informações médicas. Os relatórios médicos são, na maior parte das vezes, guardados num texto livre não estruturado e escritos com vocabulário proprietário, podendo ocasionar falhas de interpretação. Através das linguagens da Web Semântica, é possível utilizar antologias como modo de estruturar e padronizar a informação dos relatórios médicos, adicionando¬ lhe anotações semânticas. A informação contida nos relatórios pode desta forma ser publicada na Web, permitindo às máquinas o processamento automático da informação. No entanto, o processo de criação de antologias é bastante complexo, pois existe o problema de criar uma ontologia que não cubra todo o domínio pretendido. Este trabalho incide na criação de uma ontologia e respectiva povoação, através de técnicas de PLN e Aprendizagem Automática que permitem extrair a informação dos relatórios médicos. Foi desenvolvida uma aplicação, que permite ao utilizador converter relatórios do formato digital para o formato OWL. ABSTRACT: Technological evolution has caused a medicine evolution through computer systems which allow storage, gathering and availability of medical information. Medical reports are, most of the times, stored in a non-structured free text and written in a personal way so that misunderstandings may occur. Through Semantic Web languages, it’s possible to use ontology as a way to structure and standardize medical reports information by adding semantic notes. The information in those reports can, by these means, be displayed on the web, allowing machines automatic information processing. However, the process of creating ontology is very complex, as there is a risk creating of an ontology that not covering the whole desired domain. This work is about creation of an ontology and its population through NLP and Machine Learning techniques to extract information from medical reports. An application was developed which allows the user to convert reports from digital for¬ mat to OWL format.

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In this paper we describe an hybrid algorithm for an even number of processors based on an algorithm for two processors and the Overlapping Partition Method for tridiagonal systems. Moreover, we compare this hybrid method with the Partition Wang’s method in a BSP computer. Finally, we compare the theoretical computation cost of both methods for a Cray T3D computer, using the cost model that BSP model provides.

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In this paper, artificial neural networks are employed in a novel approach to identify harmonic components of single-phase nonlinear load currents, whose amplitude and phase angle are subject to unpredictable changes, even in steady-state. The first six harmonic current components are identified through the variation analysis of waveform characteristics. The effectiveness of this method is tested by applying it to the model of a single-phase active power filter, dedicated to the selective compensation of harmonic current drained by an AC controller. Simulation and experimental results are presented to validate the proposed approach. (C) 2010 Elsevier B. V. All rights reserved.

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Article in Press, Corrected Proof