Apropiación social del conocimiento - i2T

URI permanente para esta colecciónhttp://hdl.handle.net/10906/78228

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W-CDMA capacity analysis using GIS based planning tools and MATLAB simulation
(IEEE, 2000-03-29) 1st International Conference on '3G Mobile Communication Technologies
The evolution of cellular systems towards third generation (3G) or IMT-2000 seems to have a tendency to use W-CDMA as the standard access method, as ETSI decisions have showed. However, there is a question about the improvements in capacity and the wellness of this access method. One of the aspects that worry developers and researchers planning the third generation is the extended use of the Internet and more and more bandwidth hungry applications. This work shows the performance of a W-CDMA system simulated in a PC using cover maps generated with DC-Cell, a GIS based planning tool developed by the Technical University of Valencia, Spain. The maps are exported to MATLAB and used in the model. The system used consists of several microcells in a downtown area. We analyse the interference from users in the same cell and in adjacent cells and the effect in the system, assuming perfect control for each cell. The traffic generated by the simulator is voice and data. This model allows us to work with coverage that is more accurate and is a good approach to analyse the multiple access interference (MAI) problem in microcellular systems with irregular coverage. Finally, we compare the results obtained, with the performance of a similar system using TDMA.
Some parameters that affect CDMA capacity analysis. Results using GIS based simulation
(3G Mobile Communication Technologies, 2001. Second International Conference, 2001-01-01T15:55:51Z) Cardona Marcet, Narcís; 2nd International Conference on 3G Mobile Communication Technology
In previous papers we describe a model for capacity analysis in CDMA systems using DC-Cell, a GIS based planning tool developed at Universidad Politecnica de Valencia, and MATLAB. We show some initial results of that model, and now, we are exploring different parameters like cell size, proximity between cells, number of cells in the system and “clustering” CDMA in order to improve the planning process for third generation systems. In this paper we show the results for variations of some of these parameters, specifically the cell size and number of cells. In CDMA systems is quite common to suppose only one carrier frequency for capacity estimation, and it is intuitive to think that for more base stations, mean more users. However the multiple access interference problem in CDMA systems could establish a limit for that supposition in a similar way that occurs in FDMA and TDMA systems.
The Influence of Propagation Model and Sectorization over WCDMA Capacity
(IASTED International Conference Communication Systems and Networks (CSN 2002), 2002-09-09T16:05:48Z) Cardona Marcet, Narcís
In this paper we use a dynamic model that we have developed for WCDMA capacity analysis using MATLAB and a GIS based planning tool, to estimate the capacity of a mobile system under different conditions like number of cells, propagation model, sectorization and handover margin.
Up-Link/Down-Link capacity Unbalance analysis in UMTS using a GIS based Planning Tool and MATLAB simulation
(WNCG 2003 Wireless Networking Symposium, 2003, Austin, 2003-01-01T16:44:31Z) Navarro Cadavid, Andrés
Capacity analysis using simulation is not a new thing in literature. Most of the development process of UMTS standardization have used simulation tools; however, we thing that the use of GIS planning tools and matrix manipulation capacity of MATLAB can show us different scenarios and make a more realistic analysis. Some work is been doing in COST 273 in order to have more realistic scenarios for UMTS planning. Our work initially was centered in uplink analysis, but we are now working in downlink analysis, specifically in two areas: capacity in number of users for RT and NRT services, and Node B power. In this work we will show results for up-link capacity and some results for downlink capacity and BS power consumption.
Effect of terrain on electromagnetic propagation in urban environments on the Andean region, using the COST231-Walfisch-Ikegami model and GIS planning tools
(IEE, 2003-03-31) Navarro Cadavid, Andres
This paper includes some results from a research project for the development of an electromagnetic propagation algorithm considering the influence of mountain terrain in UHF (300 MHz-3 GHz) band for wireless communications systems (i.e. 800-900 MHz in DAMPS/US-TDMA/IS-136 and GSM standard). The COST231-Walfisch-Ikegami (1988, 1991) model used in this work has been shown, together with Geographic Information System (GIS) and prediction tools for mobile propagation, to facilitate propagation studies, coverage analysis and analysis of main factors for cell planning in mobile systems. The basic concepts used to design the algorithm, the parameters used in measurements and results analysis in order to verify its applicability in cellular coverage prediction are described. Measurements have been done initially in Bucaramanga, a city located in the Andean Mountain system, for IS-136 band system. Coverage predictions have been done using a locally modified version of CellView, a GIS based Planning tool developed by the Universidad Politecnica de Valencia, while for the measurements a portable monitoring unit (i.e. Miniport Receiver EB200-Rohde&Schwarz from 10 kHz-3 GHz) was used.
A virtual surgical telesimulation in micrographic dermatologic surgery (MOHS)
(Elsevier, 2003-06-01) Vélez, J.A
The development and propagation of surgical procedures in dermatology establish a need for an approach to a new way of teaching and supporting techniques which use emergent technologies. Our work is based upon a generic concept of software architecture for telemedicine applications, which could provide educational telesimulation in the dermatologic surgery technique known as Mohs micrographic surgery. This technique is used in the neoplasia resection treatment. Actually, the modules proposed are evolving in the Internet platform and are planned to interact in a cyclic manner from a diagnostic precision aid, through a planning surgical tool, to a simulator facility.
Virtual surgical tele-simulations in ophthalmology
(Elsevier, 2003-06-01) Múnera, Luis Eduardo
n a previous work, a generic software architecture for telemedicine services was proposed. This architecture was intended to be an extensible and a flexible platform where services in tele-simulation, tele-knowledge exchange, and tele-mentoring could be supported. At that time, the architecture was described as consisting of a set of interacting modules, which would provide support for the planned services, however, no module was yet detailed. In this paper, a prototype of a tele-simulation service and the way it can be supported by the architecture is described. The aim of this work is to provide virtual surgical tele-simulation in ophthalmology for ophthalmologists, trainees and doctors in remote locations. Access to surgical simulators in ophthalmology is scarce in Latin America, and providing one which is supported by an Internet-based software architecture would be helpful for practitioners and medical doctors.
Análisis de capacidad en sistemas CDMA y WCDMA, usando herramientas de planificación basadas en GIS y dinámica poliédrica
(Universitat Politècnica de València, 2003-10-17) Navarro Cadavid, Andrés; Cardona Marcet, Narcís
En este momento están entrando en operación los primeros sistemas UMTS en Europa, y están operando en varios países del mundo sistemas CDMA-2000 1xRTT, y aunque existen muchos trabajos publicados sobre la capacidad de estos sistemas, prácticamente todo lo existente se basa en el comportamiento de sistemas ideales que consideran celdas hexagonales o circulares y propagación basada en exponente inverso de la distancia y poco es lo que hay sobre el comportamiento real de dichos sistemas en entornos reales.

Sobre el exponente de pérdidas de propagación, es bien conocido que este afecta la capacidad de los sistemas CDMA; sin embargo hasta ahora no se ha considerado el efecto de los modelos de propagación que tienen en cuenta la difracción y otros fenómenos más cercanos a la realidad, y por lo tanto no se ha considerado el efecto del entorno urbano y el terreno sobre la capacidad real de los sistemas basados en CDMA.
Adaptive planning of 3G/4G systems using Q-analysis or polyhedral dynamics
(IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC, 2004-01-01) Cardona, Narcis
In this paper we present a method for use Q-analysis in the initial planning process and later dynamic adaptation for 3G/4G cellular systems that intends to balance load in order to maximize capacity and reduce lost and dropped calls independently of the type of service. We support our proposal on dynamic simulations made with an own developed tool for dynamic simulations of CDMA systems, and show initial results that partially probe our proposed method.
Dynamic planning of 3G/4G systems using Q-analysis
(2004-05-25) Cardona, Narcis
In this paper we present a method for use Q-analysis in the initial planning process and later dynamic adaptation for 3G/4G cellular systems that intends to balance load in order to maximize capacity and reduce lost and dropped calls independently of the type of service. We support our proposal on dynamic simulations made with an own developed tool for dynamic simulations of CDMA systems, and show initial results that partially probe our proposed method.
Analysis of the influence of sectorization in the capacity of WCDMA using topological invariants
(Lu W.W., 2005-05-17) Navarro Cadavid, Andrés
Polyhedral analysis and simplicial complexes have been used in areas such as database design, traffic and social sciences, since work from Atkin. In this paper we make a short introduction on simplicial complexes and then propose the use of some topological invariants of simplicial complexes such is the structure vector to qualitatively predict the capacity of a WCDMA system and improve the planning process of CDMA based systems used in third generation. We compare results obtained from structural vector with results obtained from a dynamic simulator in order to show the relation between structural vector and capacity.
An implementation, modification and verification written in Java of an indoor propagation prediction model for 802.11 wlan's
( Intel Corporation,Qualcomm,Sieneon Technologies,Cetecom,Larsen and Toubro Infotech,Texas Instruments, 2006-01-01) López Ocampo, Sandra Paulina
In this paper, we show the implementation of a propagation model described in [1] using the Java programming language with a new shadowing procedure that improves the algorithm execution time. We shown also results from measurements made in some buildings with a diversity of constructive materials, in order to compare the model with real data. As part of this work we have made an extensive characterization of some constructive materials used commonly in Colombia and some Latin American Countries.
Seguridad en redes inalámbricas 802.11
(Universidad Icesi, 2006-07-28) Madrid Molina, Juan Manuel
Lack of security in wireless LANs is a problem which has not been correctly assessed by network managers and people in charge of information, in spite of its seriousness. This article presents the existing technologies for heightening the security level in 802.11 wireless LANs, among with their advantages, disadvantages and application scenarios.
Herramienta gráfica de modelado de redes inalámbricas basada en modelos de propagación de señales en interiores
(Universidad Icesi, 2006-07-28) Osorio Betancur, Juan David; López Ocampo, Sandra Paulina; Navarro Cadavid, Andrés
El presente artículo describe el proceso de implementación de un modelo de predicción de la propagación de señales en interiores, basado en el modelo semiempírico de K. W. Cheung, J. H. M. Sau, y R. D. Murch,[1] donde se tienen en cuenta la atenuacióndebida a la distancia, el ángulo de incidencia sobre las paredes, laatenuación asociada a estas mismas y las zonas de Fresnel.Los datos del entorno a simular son tomados de un archivo DXF que debe seguir un formato establecido. Se obtienen del usuario la atenuación asociada a cada tipo de pared y la ubicacióndel punto de acceso. También se desarrolla un algoritmo desombreado que optimiza el tiempo de simulación debido a su sencillez. Finalmente se muestra la comparación de los resultados de la simulación y los datos obtenidos en la prueba de campo.
QoS and multipath routing in vehicular network
(ACM Press, 2007-05-14) Umaña, Sandra Céspedes
Las redes Vehiculares Ad-Hoc o redes VANET, consisten en la asociación espontánea de un conjunto de vehículos equipados con tecnología de comunicación inalámbrica, que circulan y cambian dinámicamente su posición e intercambian datos entre sí. Estas redes fueron pensadas como segmentos autónomos y de direccionamiento plano, sin embargo, su estudio ha mostrado los beneficios de interconectarlas a segmentos de redes de infraestructura e Internet. El presente artículo revisa, mediante el uso de una herramienta de simulación, las mejoras globales de las métricas de calidad de servicio de la red, logradas mediante el uso de un protocolo de ruteo multi caminos. El modelo consta de un segmento de red fija (Internet), dos gateway reactivos y dos segmentos jerárquicos de redes VANET IPv6, las cuales están compuestas por nodos con alto grado de movilidad, tales como los vehículos en un entorno urbano.
WLAN's access points java based automatic location tool
(World Wireless Congress, 2007-05-23) Navarro Cadavid, Andrés
In this paper, we will show the development process and the results obtained with a Java based toll for automatic location of WLAN Access Points. We will describe the algorithm developed and the results obtained until the time we wrote the paper. Also we will discuss future work and possible evolution for the tool.
Las Facultades de Ingeniería y Su Papel en la Definición de Políticas Públicas: Participación de la Universidad Icesi en la Definición del Estándar Colombiano de Interoperabilidad GEL-XML
(ResearchGate, 2008-01-01) Tamura Morimitsu, Gabriel
This paper presents the results of the Colombian HL7 foundation and the Icesi University joint efforts, in terms of the contribution of their work in the checking of interoperability properties the GEL-XML standards definition, which is being developed by the “Agenda de conectividad”, a program of the Colombian Communications Ministry. The GEL-XML standards collection is fundamental for the country because of its scope and impact in the electronic data exchange among its public and private entities. It is considered by the national government as one of the foundations for the e-government strategy, which in turn is one of the basements to achieve the so called “digital leap”
Introduccion. Descripción del proyecto y del problema a resolver
(Universidad Autónoma de Occidente, 2008-01-01) Navarro Cadavid, Andrés
El desarrollo del presente proyecto implica una combinación de diferentes conocimientos tanto de software como de hardware, relacionados con la computación móvil, middleware, agentes móviles y mecanismos de autenticación, que le permitan a un dispositivo móvil interoperar y desplazarse libremente haciendo uso de diferentes redes inalámbricas parn mantener su conec tividad sin que sea indispensable la intervención del usuario. Se desarrolla un mecanismo que permita movilidad semitrans parente, es decir, que permita al dispositivo móvil realizar el proceso de re-selección vertical, aunque no necesariamente Jwnd off vertical.
Sistema universal para portabilidad de dispositivos móviles en ambientes de redes inalámbricas heterogéneas - Primera edición
(Universidad Autónoma de Occidente, 2008-01-01) Tamura Morimitsu, Gabriel
El presente libro es el resultado de un proyecto de investigación que ha sido desarrollado por algunos miembros del consorcio de investigación i2ComM, con el apoyo de Colciencias por medio de un proyecto de recuperación contingente, y cuya finalidad es abordar los conceptos y desarrollar herramientas que permitan al usuario un tránsito semi-transparente por redes inalámbricas heterogéneas, lo que no es para nada una tarea fácil, como se podrá ver a lo largo de los diferentes capítulos. Con este libro pretendemos que el lector tenga una aproximación tanto teórica como práctica a un problema tecnológico actual, de tal forma que le sirva de referencia para continuar trabajos de investigación en esta área del conocimiento, o simplemente como un punto de referencia o una guía de estudio para un curso de redes convergentes.
Implementación de la arquitectura del sistema cliente universal para dispositivos móviles
(Universidad Autónoma de Occidente, 2008-01-01) Tamura Morimitsu, Gabriel
En este capítulo se presenta la implementación de la arquitectura del Sistema de Cliente Universal, y las respectivas pruebas de concepto, según lo planteado en el capítulo 4. Este desarrollo e integración se ha realizado en las plataformas definidas en el proyecto, es decir, Windows XP/C#, Windows Mobile/C# y Linux/Java. Considera en su alcance la integración y ejecución automática de las funciones de monitoreo de redes disponibles identificadas en todas las interfaces de red disponibles en el dispositivo en el que se esté ejecutando el sistema, la valora ción de las redes descubiertas y la selección de la que mejores características ofrezca según los parámetros de preferencia del usuario, y la conmutación a la red seleccionada. Como aplica ción de prueba de concepto, se planteó un componente de Chat o mensajería instantánea con las funcionalidades básicas.

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