Tecnura

12-25

Authors: José Alexander Martínez, Fredy Hernán Martínez S

We propose a data-analysis-based methodology for maintaining trees that affect power distribution networks. From the information captured in the field, we use fuzzy-logic-based techniques and models together with genetic algorithms so as to focus maintenance activities on the optimal time and place. The strategy is aimed at two key aspects: first, the history of failure events caused by trees on medium-voltage power supply systems; this information is used to calculate quality indicators such as energy-not-supplied (ENS) and number-of-users (NU) affected due to falling trees only. In this case we use a fuzzy-logic-based system to weight and find the critical circuits on which forest maintenance should be performed. Second, we construct an objective function based on tree-to-network distances and growth patterns of trees (classifed per species) in order to simulate forest maintenance; this is achieved using a genetic algorithm to determine optimum pruning cycles for a given power supply system. We use real historical data of medium voltage circuits for system setting as well as for performance evaluation.

38-46

Authors: Diego Mauricio Camargo Casas

This paper presents a pre-coding technique, known as "Dirty Paper Coding", which allows transmission with limited levels of power over channels where the interference level is known by the transmitter. The interference levels considered have finite variance-just like in MIMO (multiple-input and multiple-output) communications, where there is ISI (inter-symbol interference), Intra-Cell and Inter-Cell interference among other types of interference. The role of proper scaling parameters at the transmitter and receiver is described. Such parameters make use of a linear estimator that minimizes the mean square error of the signals involved. Moreover, a quantization scheme equivalent to a module operation is explained in detail. The purpose of this scheme is to pre-cancel the interference at the transmitter, showing that interference knowledge is used by the encoder as much as possible, namely the encoder attempts to adapt itself to the interference value. Thus, it is possible to decode the signal to make it look almost like the original signal since the new signal is now totally independent of interference.

55-62

Authors: Edgar Alirio Aguirre, Luis F. Pedraza, Gabriel A. Puerta A

This paper presents an evaluation of the WCETT (Weighted Cumulative Expected Transmission Time) routing metric setup for a cognitive radio network. This metric setup is based on the software application called CRCN (Cognitive Radio Cognitive Network Simulator), which runs over the simulation environment called NS2 (Network Simulator 2). Comparative experiments to assess throughput values were conducted for the following protocols: MAC802.11, MACCON, MACN, Simple and TDMA

77-89

Authors: Sandra Ximena Carvajal Quintero, Juan David Marín Jiménez

Distributed Generation (DG) has emerged as an important alternative to provide electrical energy since it could increase the reliability and security of electric power supply in the short, medium and long term. Despite these potential advantages, the Colombian regulatory framework does not recognize DG as a valid activity within the country's interconnected system and, as such, no policy exists to encourage investment in small-scale generation projects. This article first describes the technical and financial aspects of DG, and then analyses regulatory proposals regarding the inclusion of DG in power systems outside Colombia. These aspects are then brought together in a mental model based on the concepts of feedback theories as well as of cause and effect relationships; such concepts are part of the System Dynamics methodology (SD). This model is aimed at creating a virtual world which would allow the usefulness of various regulatory alternatives to be evaluated and thus an appropriate option to be chosen according to the regulation that best fits technical, climactic and economic conditions, and also according to the market structure used in the Colombian interconnected system.

107-115

Authors: Duvan Cardona, Danilo López, Cesar A. Hernández

This investigation work shows the way to implement the rapidly transformed of Fourier using the algorithms of Cooley-Tukey, applied to the analysis and calculation of the harmonic distortion in homes and small businesses that it's don't knows the energy's quality that is delivered daily. The investigation is based on a diferent parts of hardware necesary for the recmicrocontroller architecture for good perfoman-koning of the FFT of 1024 points and the reckoce whit a high level language, olso develop the ning of THD level.