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Ítem Software platform for services in Colombian cities using the Living Labs approach(Ieee, 2011-12-05) Navarro Cadavid, AndrésComponent Based Software Engineering is a way to improve software modularization and to embed architectural concerns in the source code. Making explicit the architectural concerns in code helps to mitigate the problem of architectural erosion. The restructuring of legacy code with components in mind requires the use of tools to assess compliance with component programming principles. The property of communication integrity is one of the major principles for implementing software architectures. However, there is a paucity of tools for assessing the quality of code components. To cope with this issue, we define a component model in Java and a tool for identifying component types, which relies on a set of rules to statically check potential violations of the communication integrity property in Java source code. We illustrate its application with a case study and report the results of our experiments with it.Ítem SNR estimation for on body communications in MB OFDM Ultra Wide Band communications(Ieee Computer Society, 2010-04-12) Navarro Cadavid, AndrésIn this paper a new signal to noise ratio estimator algorithm based on the moments of the received signal is presented. The novel algorithm has been designed for Ultra Wide Band communications based on Multi Band Orthogonal Frequency Division Multiplexing (MB-OFDM) communication systems. In this proposal, we analyze the behavior of ultra wide band channels when the time and frequency fading have fast changes. Hence, different time coherence values were considered and all the frequency fading models are based in real measurements made in an anechoic chamber. It is remarkable that all the measurement campaigns were focused on body communications. We conclude that the proposed model can be used for SNR estimation in adaptive modulation and channel estimation and link quality control in MB OFDM systems. The performance of the proposed SNR estimation algorithm and its comparison with other SNR estimators was achieved through simulations based on real channel measurements.Ítem Statistical adjustment of empirical propagation path loss models to the COST 2100 Cali reference scenario(Antennas and Propagation Society International Symposium (APSURSI), 2012 IEEE, 2012-11-12) Navarro Cadavid, AndrésPropagation models used to plan outdoor wireless networks on urban environment, tend to include a high degree of empirical component. These are derived from the difficulties of accurately estimate the influence of obstacles, buildings and terrain in the signal path loss. Therefore, the final equation usually contains constants, and coefficients for the different terms, mainly obtained by statistical analysis of measurement sets, collected during drive tests on large areas of the city. Unfortunately, such results are only truly valid for the city or parts of the city on which the measurements were taken. They can also be considered appropriate for similar areas or cities at the most. If the areas are not similar enough however, a process of adjustment is necessary, leading to the finding of new constants and coefficients. The purpose of this paper is to discuss some of the findings during the process of statistically adjust the Okumura-Hata and Walfisch-Bertoni models to the Cali scenario, using measurements.