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Ítem Herramienta para el cálculo de invariantes topológicos(Universidad Icesi, 2006-07-28) Pérez Escobar, Aura Lucía; Valdés Duque, Javier Guillermo; Bedoya Giraldo, Juan PabloIn this article there is a description of the process that yielded a software tool which was designed with the purpose of calculating four specific topological invariants, among which we count the Betti numbers, the dimension of the complex, the q-array and the Euler- Poincaré characteristic. The meaning of all the obtained results is viewed from Professor Luis Eduardo Múnera’s perspective, which in turn proposes a formal mathematical definition of cohesion and coupling, two important criteria when evaluating modularity of a software design. The article also describes the tool itself, its functionality and the importance it has to the professor’s project. In order to portrait a full comprehensible description of both the process and the tool, an historical framework is established through a brief review of the evolution of the different ideas and concepts behind the project, and the way and pace with which these were assimilated by the student team that were appointed to the task.Ítem Realimentación como paradigma de integración conceptual en educación(Universidad Icesi, 2006-07-28) Vega Barvo, Daniel MartínFeedback is a key phenomena and concept in Control theory and systemic thinking. Its importance and historic evolution in different areas of endeavor are analized.Ítem Servicios WEB : Distribución e integración(Universidad Icesi, 2006-07-28) Arboleda Cobo, Liliana MaríaThis article presents an overview of web services and the way enterprises should monitor and administer them. To accomplish this goal, the different standards involved in their development are presented, along with the description of their basic functional framework, emphasizing on how the use of this kind of services provides both a basic process distribution and, an integration of the information managed by the enterprise in its business applications. Finally, a brief explanation is given about the global benefits accomplished by using web services and the main implications of their use in an organizational environment.Ítem Sistemas MIMO como Alternativa para el Control del Efecto Multitrayectoria y de la Interferencia Co-Canal en Sistemas de Radio Móvil Satelital y Terrestre(Universidad Icesi, 2006-07-28) García Ariza, Alexis PaoloThe Multiple Inputs Multiple Outputs -MIMO- Systems are advanced technique both the radio signal fading control, problem associated to multipath effects, and co-channel interference mitigation in mobile systems, using array antennas and space- time processing.1 This technique lets improve the wireless systems performance and increase its data transmission capacity under dynamic environments. The paper presents both the basic concepts over multipath propagation in mobile satellite and terrestrial systems, and a research proposal in MIMO techniques for DS-CDMA systems. This research is presented to European Union for RadioGIS- UIS and MCG-UPV groups, supported by the Alban Program - High Level Scholarships for Latin America-. The research will be development at Communications Department of Polytechnic University of Valencia -UPV- like author’s Doctoral work.Ítem Alineamiento de múltiples secuencias de aminoácidos usando algoritmos genéticos(Universidad Icesi, 2006-10-11) Solanilla, Luis FelipeThis article describes a genetic algorithm and its implementation that it allows the alignment of multiple sequences of amino acids by means of relocations that simulate the gaps insertion (holes) and actions of recombination to obtain higher scores in the alignment. Such scores are obtained by means of the method of the sum of even, in which there are considered all the possible combinations of amino acids in each column of the alignment and they are qualified being based on the punctuations of the matrix BLOSUM62.Ítem Propuesta para la interconexión WLA N multicelda basada en el estándar IE 802.11e y Diff Serv(Universidad Icesi, 2008-07-24) Viteri, Carlos A.; Gómez Ordóñez, Javier AndrésNowadays, the convergence of services as video, voice and data over a common infrastructure has become an important issue that requires special treatment in order to achieve an optimum Quality of Service (QoS) level. This is the case of the IEEE standard 802.11 MAC layer providing a fair medium access treatment according to the application needs. In addition, the deployment of WLANs in public places (hotspots) has been made in a one-cell oriented way and the network design over an outdoor environment involving more than one cell has not been considered. This fact leads to our proposal of an “Outdoor Multicell WLAN supporting 802.11e” design based on the solutions provided by special techniques commonly used by cellular telephony in order to solve problems related to outdoor scenarios. Our design is complemented by an integrated wired/wireless network architecture in order to achieve end to end QoS. This integration uses the Differentiated Services (DiffServ) QoS architecture which maps its traffic classification into the 802 11e and 802.1D link layer technologies.Ítem Desempeño de redes de múltiple salto ante ataque de denegación de servicio basado en tráfico(Universidad Icesi, 2008-07-24) Ramírez Sarmiento, César Andrés; Peña, Néstor MisaelThe Multi-hop wireless networks or ad hoc networks are build on MAC IEEE 802.11 DCF protocol, which was originally designet for wireless LAN. This adaptation have revealed problems and vulnerabilities that a buased on traffic DoS attack might take advantage, avoiding normal clients to access or provide its services. In wired networks, hardware devices and preventive measures like encryption and authentication are used to the defense against the attacks, but some-times due of ad hoc networks physical conditions, this measures could not be applied, then the network performance falls. For the simulations of base on traffic DoS consequences on MAC layer protocol, Qualnet@ simulation tool was used. To improve the performance of the multi-hop network in presence of a based on traffic DoS, we propose as a preventive measure to increase and setup the default retry limits of MAC layer and a modification of BEB algorithm. These changes, reduce the effects of the DoS and improve the network performance in terms of throughput and packet delivery ratio.Ítem Arquitectura para la interconectividad de la tecnología Bluetooth con redes IP cableadas para transporte de voz(Universidad Icesi, 2008-07-24) Guzmán F., Juan P.; Hurtado G., Javier A.; Caicedo, Oscar Mauricio; Reinoso R., Daryan F.; Martínez, Francisco OrlandoEn el presente documento se estudian los criterios y requerimientos tecnológicos necesarios para la construcción de una arquitectura que permita la interconectividad de Bluetooth con redes Ethernet como base para la prestación de servicios de VoIP; adicionalmente se detallan los resultados obtenidos a partir de un proceso de validación de la arquitectura con base en la simulación de una serie de scenarios y un análisis de desempeño de un prototipo funcional para la prestación de dichos servicios.Ítem Proceso de consultas móviles adaptables a diferentes tipos de negocios basados en telefonía celular (Metamorf)(Universidad Icesi, 2008-07-24) Montes Hurtado, Diana Patricia; Cruz Galvis, Daniel Felipe; Garzón Giraldo, Julián Eduardo; Zúñiga Cañón, Claudia LilianaMetamorfis a research Project, introducing the development of a process centered in a mobile solution under a service-oriented architecture, with the capacity of adapting to all different business contests, providing a system that, with the use of Web Services through TCP/IP connections, allows for execution of queries in mobile environments.Ítem Vol. 6 No. 11, Enero/Junio 2008 / SISTEMAS y TELEMATICA(Universidad Icesi, 2008-01-01) Universidad IcesiEsta edición incluye: Caracterización del consumo de energía y el desempeño de las aplicaciones streaming sobre redes inalámbricas WLAN; Estimación de capacidad en una red IE 802.11e para entornos outdoor multicelda; Descubrimiento e interacción de servicios móviles ubicuos utilizando Bluetooth y WiFi; Capacidad de una red inalámbrica en malla, para el transporte de voz sobre IP y datos en un entorno rural; Propuesta para la interconexión WLAN multicelda basada en el estándar IE 802.11e y Diff Serv; Desempeño de redes de múltiple salto ante ataque de denegación de servicio basado en tráfico; Arquitectura para la interconectividad de la tecnología Bluetooth con redes IP cableadas para transporte de voz; Propuesta de arquitectura para facturación y pago por proximidad de servicios ubicuos en el contexto colombiano; y Proceso de consultas móviles adaptables a diferentes tipos de negocios basados en telefonía celular (Metamorf).