Tecnura

33-46

Authors: Juan Jairo Vaca González, Cristhian Andrés Peña Caro, Harold Vacca González

Serial robotic manipulators are efficient tools to carry out repetitive and precision tasks in industry, as long as there is understanding of the involved kinematics in the positioning and orientation of the final effector. This article presents a methodology to the solution of an inverse kinematic serial robot (Melfa RV-2A) problem through genetic algorithm (GA) implementation using the Screws direct kinematic model (SDKM). In order to do this, the Screws parameters that model the main four robot joints are obtained, the related workspace is calculated and the GA is designed considering a multi objective function of position and orientation located in the final effector, with respect to a coordinate and orientation of an established target point. The GA validation is carried out according to aptitude, convergence time and number of generations used in order to reach the main objective. Therefore, the implementation of a SDKM-based AG is a tool that could be used to calculate the inverse kinematic of serial robots. This implementation allows to establishing for the first time the matrix exhibition of a direct kinematic system to obtain the inverse kinematic solution of a serial robot. In consequence, it is demonstrated that this methodology is feasible and efficient to solve the inverse kinematic of any manipulator robot.

59-70

Authors: Silvio Delvasto Arjona, Álvaro Guzmán Aponte, John Alexander Torres León, Martha Lorena Cedeño Venté, David Felipe Acosta Guarín

This article presents the results of a research on the use of glass powder as substitute of feldspar for manufacturing stoneware tiles. Mixtures were prepared in which glass powder substituted feldspar in two different percentages (25 wt% and 50 wt%). Specimens of the obtained mixtures were molded, dried and sintered. Physical (apparent density, porousness, absorption, among others) and mechanical properties (flexion resistance) of standard sintered bodies (V0) were compared to the sintered bodies in which the melting material was substituted in the formulation by glass powder in percentages of 25% and 50% (V25 and V50). It was found that the glass powder addition in the formulations caused decrease in flexion resistance and increase in water absorption values. However, the melting action of glass powder reduced the sintering temperature in regards with the standard mixture in 150 °C for substitutions of 50% and 25%, respectively. By using Scanning Electron Microscopy (SEM) needles of primary mullite and secondary mullite (elongated needles) in a vitreous phase were identified

83-92

Authors: Alejandro Rivera Roldán, Miguel Alberto Becerra Botero, Jaime Alberto Guzmán Luna

This paper presents a vibration analysis on induction motors using Hidden Markov Models (HMM) applied to features obtained from the Empirical Mode Decomposition (EMD) and Hilbert-Huang transform to vibration signals obtained in the coordinates x and y, in order to detect malfunctions in bearings and bars. Additionally, a comparative analysis of the ability of the vibration signals in the x and y directions to provide information for failures detection is presented. Thus, an ergodic HMM initialized and trained by expectation maximization algorithm with convergence at 10e-7 and maximum iterations of 100 was applied to the feature space and its performance was determined by cross-validation with 80-20 with 30 fold for obtaining high performance fault detection in terms of accuracy

109-120

Authors: Carlos Javier Carvajal Montealegre

This paper describes the data mining process to obtain classification rules over an information security incident data collection, explaining in detail the use of genetic programming as a mean to model the incidents behavior and representing such rules as decision trees. The described mining process includes several tasks, such as the GP (Genetic Programming) approach evaluation, the individual's representation and the algorithm parameters tuning to upgrade the performance. The paper concludes with the result analysis and the description of the rules obtained, suggesting measures to avoid the occurrence of new informatics attacks. This paper is a part of the thesis work degree: Information Security Incident Analytics by Data Mining for Behavioral Modeling and Pattern Recognition (Carvajal, 2012)

133-144

Authors: María Elena Bernal Loaiza, German Cock Sarmiento, Jorge Hernán Restrepo Correa

This research focuses on the design of a simulation of the process in a flexible manufacturing cell at the Faculty of Engineering of the Universidad Tecnológica de Pereira, aiming at measuring and choosing the one alternative of solution that improves to a greater degree the productivity of the current system using the results provided by the software Promodel. In order to do this, the stages of the simulation as definition of the system, model formulation, identification of variables, data collection, implementation and interpretation were used. As a result, the productivity was calculated taking into account the variables of the model and simulation time, at the same time the information from each of the locations was interpreted, finding the percentage of use and total number of entities for locations with unit capacity, and for locations with greater capacity there is information concerning to the percentage of empty time, partially occupied, full and unavailable regarding available time. In contrast to other simulations, in this design, on the networks the type of network Crane was used, associated to the resources of model. Which facilitates the movement of robot arms with the parts circulating through the system.

157-170

Authors: Rafael Andres Robayo Salazar, Pedro Enrique Mattey Centeno, Yimmy Fernando Silva Urrego, Diana Marcela Burgos Galindo, Silvio Delvasto Arjona

The amount of construction, remodeling and demolition activities in the Colombian cities increases constantly due to growth and economic development of the urban population. However, these practices create big quantities of debris that have currently become an environmental problem in cities such as Cali (Colombia). The search for integral solutions that allow for an adequate management and reuse of the different materials that form construction and demolition debris was unthinkable some decades ago. Nonetheless, nowadays it is an urgent challenge for different sectors in the society that must join efforts to find solutions. Regarding this, the present article shows an analysis about the currently situation of the construction debris management in the aforementioned city and proposes different actions according to the necessary opportunities and challenges to achieve an integral management and reuse of these materials. The analysis of this topic could be a guide for future research, as well as promote its priority in the public agenda, creating the necessary conditions for the recycling process of the construction and demolition wastes to become a viable possibility in the Colombian cities through the obtained experience.

191-200

Authors: Wilson Rodríguez Calderón, Myriam Rocío Pallares-Muñoz

When we need to determine the solution of a nonlinear equation there are two options: closed-methods which use intervals that contain the root and during the iterative process reduce the size of natural way, and, open-methods that represent an attractive option as they do not require an initial interval enclosure. In general, we know open-methods are more efficient computationally though they do not always converge. In this paper we are presenting a divergence case analysis when we use the method of fixed point iteration to find the normal height in a rectangular channel using the Manning equation. To solve this problem, we propose applying two strategies (developed by authors) that allow to modifying the iteration function making additional formulations of the traditional method and its convergence theorem. Although Manning equation is solved with other methods like Newton when we use the iteration method of fixed-point an interesting divergence situation is presented which can be solved with a convergence higher than quadratic over the initial iterations. The proposed strategies have been tested in two cases; a study of divergence of square root of real numbers was made previously by authors for testing. Results in both cases have been successful. We present comparisons because are important for seeing the advantage of proposed strategies versus the most representative open-methods.