Tecnura

17-34

Authors: Alejandra Martínez Peñaloza, German Osma-Pinto, Gabriel Ordóñez-Plata

Context: Studies carried out in low voltage networks have explored the modeling of linear single-phase loads (such as motors) and non-linear ones (such as those based on power electronics). However, induction motors exhibit non-linear characteristics between voltage and current due to the saturation of their magnetic parts. Therefore, it is necessary to study induction motors in the frequency domain with a model that allows reviewing the characteristic nonlinearity of their voltage-current interaction. Methodology: This article presents the frequency domain modeling of a single-phase induction motor used as a silent air extractor (127 V, 60 Hz, 66 W), which presents a capacitive behavior (fp = 0,93 in leading) and harmonic distortion due to a third-order component (7,0%) when fed with a pure sinusoidal voltage of 127 V. Results: This work establishes the parameters of two approaches to the Norton equivalent model (coupled and decoupled admittance matrix) which are used to estimate the distorted current signal and the values of consumed active and non-active power. The results show comparisons errors of P, Q, THDi, and NRMSE indices of less than 7, 4, 14, and 3%, respectively. Conclusions: The parameters of the Norton equivalent model estimated for the single-phase induction motor allow calculating the current signal with a high degree of precision. This signal exhibits nonlinear characteristics and a capacitive behavior due to the permanent presence of a capacitor aiding the start and operation of the engine.

49-69

Authors: Yeraldin Arias Battle, Guillermo Roa Rodríguez

Context: Small and medium enterprises (SMEs) are critic for economic development and job creation in Colombia, as a developing country. Specifically, those in the IT consulting subsector produced the highest profits in the technological area, according to the 2015 records (Ministerio de las Tecnologias de la Informacion y las Comunicaciones de Colombia, 2015). However, despite their growing rate and huge impact, one of the main factors that affects their problems is the selection of the project management method; actually, authors as Campanelli and Parreiras show a remarkable trend into the agile frameworks adaptation inside the companies (Silveira Campanelli & Silva Parreiras, 2015). Also, Whitney and Daniels, strengthen the idea of the potential that have the agile framework on IT projects due to its flexibility when changing situations appear with respect to predictive methods (Whitney & Daniels, 2013). Method: For the development of the research, it was proposed, to characterize and define the common critical aspects of the managed projects, correlate the common critical aspects identified, with agile frameworks in project management, design an agile model in project management for IT consulting SMEs in Bogotá and finally Validate the model developed. Result: As a result of the research carried out, the model for IT consulting SMEs in Bogotá was designed and validated, on a project developed by one of the companies in the representative sample, which met the characteristics of the study, on which a percentage was observed improvement of 77%, over time, 57% in costs and its scope was not affected, complying with what the client requires. Based on the results obtained when implementing the developed model. Conclusions: It is inferred that by implementing the model in the projects developed by IT consulting companies in Bogotá, they can have satisfactory results in the development of their projects, in terms of time, cost and scope. Support: Universidad Militar Nueva Granada

87-129

Authors: Oscar Danilo Montoya Giraldo, Karen Julieth Bohórquez-Bautista , Daniel Alejandro Moreno-Arias, Walter Gil-González

Objective: This article presents an analysis of different optimization methodologies, which aims to make an objective comparison between metaheuristic and convex optimization methods in distribution networks, focusing on the inclusion of distributed generation (DG). The MATLAB software is used as a tool for implementation and obtaining results. The objective was to determine the optimal size of the DGs to be integrated into the networks, with the purpose of reducing the active power losses (objective function). Methodology: Based on the specialized literature, the methodologies are selected, and the bases and conditions for the implementation of the optimization techniques are determined. In the case of second-order cone programming (SOCP), the relaxation of the nonlinear optimal power flow (OPF) problem is performed in order to use convex optimization. Then, the structures of each technique are established and applied in the MATLAB software. Due to the iterative nature of metaheuristic methods, the data corresponding to 100 compilations for each algorithm are collected. Finally, by means of a statistical analysis, the optimal solutions for the objective function in each methodology are determined, and, with these results, the different methods applied to the networks are compared. Results: By analyzing 33- and 69-node systems, it is demonstrated that metaheuristic methods are able to effectively size DGs in distribution systems and yield good results that are similar and comparable to SOCP regarding the OPF problem. Genetic algorithms (GA) showed the best results for the studied implementation, even surpassing the SOCP. Conclusions: Metaheuristic methods proved to be algorithms with a high computational efficiency and are suitable for real-time applications if implemented in distribution systems with well-defined conditions. These techniques provide innovative ideas because they are not rigid algorithms, which makes them very versatile methods that can be adapted to any combinatorial optimization problem and software, yielding results even at the convex optimization level.

149-164

Authors: Luis Fernando Restrepo Betancur

ABSTRACT Context: The present research is related to the number of publications and citations in computational science in South America in the last twenty years. The measurement of scientific production is of great impact in order to evaluate the production of a country, as well research groups, authors and university centers, among other aspects. Method: The research is classified as a longitudinal descriptive comparative study. The information was collected from the SCImago Journal & Country Rank platform, where the variables evaluated correspond to the different topics related to the area of computer science. The statistical processing of the information was carried out by means of the cluster technique, multivariate analysis of variance (MANOVA), Biplot analysis by the Procrustes method, complemented with the nonparametric technique of Spearman. The SAS University statistical package was used. Results: Brazil is statistically different from the other nations of the southern part of the American continent in terms of scientific dissemination in the area of computer science. There is a directly proportional relationship between the different topics evaluated, the highest correlation between nations was between Argentina, Brazil, Chile and Venezuela. Conclusions: Brazil is the South American country with the highest number of publications and citations in the different areas of computer science, followed by Argentina, Colombia and Chile, where the topic with the highest impact corresponds to applied computational sciences and the lowest is related to human-computer interaction.

190-212

Authors: osé Andrés Gómez Romero, Rosa-María Rivas-García, Adriana Valencia-Valencia, Hugo-Armando Fragoso-Cano, Omar García-Jiménez, José-Carlos-Alberto Ortíz-Acle

Context: In the last decades, one has the impression that the term sustainable development has evolved towards social responsibility and that the activities carried out by organizations and institutions are very similar. Nevertheless, this paper presents a theoretical discussion of the contribution of social responsibility. The question of this research is: through indicators of general interest and scientific production, it is possible to determine the evolution of sustainable development towards social responsibility? Methodology: Using the non-participatory method of secondary data analysis, secondary data from articles in the Redalyc, WorldCat, Microsoft Academic, Scopus, and Web of Science databases and specialized books on the topics were analyzed. Google Ngram Viewer and Google Trends were used to compare the variations of the indicators of scientific production and interest. Results: Through secondary data analysis, it was possible to establish indicators of general interest and scientific production. A discussion is presented on the evolution of sustainable development towards social responsibility. Conclusions: The results showed that the evolution of sustainable development towards social responsibility was not surpassed over time, except at some moments and in specific geographical locations.