Revista EIA

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Indicadores de alerta temprana de vulnerabilidad macroeconómica

Giraldo, Jorge Alberto | 2008

Las crisis financieras generan efectos macroeconómicos nocivos que terminan por afectar el nivel de vida de la mayoría de la población. La identificación, prevención o minimización de sus efectos es tarea de las autoridades económicas, que utilizan distintas herramientas de diagnóstico. En este artículo se explica la metodología de Goldstein, Kaminsky y Reinhart para construir un sistema de indicadores de alerta temprana de crisis financieras, que introduce conceptos innovadores para la realización del análisis y, además, está diseñada para ser aplicada en los países considerados mercados emergentes.

Patologías, causas y soluciones del concreto arquitectónico en Medellín

Figueroa, T. (Tatiana) | 2014-05-12

This paper discusses the most important results of a research focused on the construction process of architectonical concrete, presenting as a final result a handbook with recommendations on how to build architectonical concrete elements in the city of Medellin (Colombia). Architectonical concrete is a construction material which is able to supply both structural stability and definitive finishing. The research started by the definition of existing defects as well as their measuring techniques and tolerances. A statistical study was made in order to determine the most common defects on concrete surfaces in Medellin city. Possible causes of the most common defects were determined and, as a result of the analysis of each cause, general and particular solutions were given. General solutions focused on materials, equipment and the building process whereas particular solutions were given to each defect. Finally, the results herein presented constitute an advance in developing a regional specification, which will allow for the standardization of the processes involved on architectonical concrete construction.

Un patrón de interacción entre diagramas de actividades UML y sistemas workflow

Tabares-Betancur, M. S. (Marta Silvia) | 2014-05-12

In software development environments there is a big interest to look and develop techniques that could integrate transactional systems with Workflow systems in order to support the business processes in organizations. Nevertheless, in the software industry it is not common to find techniques or practices that facilitate the development of system models according to the business processes. In this article we define a development pattern to standardize the interaction between UML 2.0 activity diagrams, which represent the operations of a system, and the business processes automated by means of Workflow technologies. The traceability of the above mentioned interaction is supported by means of traceability models that control the evolution of both operations of the business and of the system. To show the application of the pattern a case study is developed.

Generación del diagrama de secuencias de UML 2.1.1 desde esquemas preconceptuales

Zapata-Jaramillo, C. M. (Carlos Mario) | 2014-05-12

Sequence diagram is a conceptual schema for representing behavior of a system. For performing such a task, it employs the object spec from a scenario and the sequence of messages exchanged among the objects. These elements describe a transaction of the system. Several approaches try the automated generation of conceptual models (like sequence diagram). Some of them use natural language as a starting point, but they are focused on other diagrams. Some others are focused on sequence diagram, but they do not obtain elements like combined fragments describing several logical constraints of the system. Other approaches use source code as a starting point, but source code can be related to an advanced phase of the software development life cycle. In this paper we define a method based on heuristic rules for obtaining automatically the elements of the sequence diagram (including combined fragments) from pre-conceptual schemas. These heuristic rules are implemented in the AToM3 tool and applied in a case study.

Conditional volatility of Colombian Governmental fixed income securities as a predictor of short-term returns

Pantoja-Robayo, J. O. (Javier Orlando) | 2014-05-12

De acuerdo con la literatura las tasas de interés futuras de largo plazo ofrecen información relevante que las convierte en un buen predictor de la estructura de retornos de corto plazo. Este artículo encuentra que el factor de volatilidad condicional posee información para predecir la prima a plazo con intervalos de seis meses para diferentes vencimientos. En otras palabras, incluir la volatilidad condicional como factor permite captar las señales de riesgo en consonancia con las expectativas de los agentes. Se evidencia, además, un proceso lento de reversión a la media para diferentes vencimientos en los títulos gubernamentales, lo cual incide sobre la capacidad de predicción, que en este caso muestra ser mayor para vencimientos más tardíos. Por otra parte, se presenta evidencia sobre la caída del mercado colombiano en mayo de 2006, hecho que generó condiciones especiales de operación, además de impactar sobre la percepción de riesgo de los agentes.

Enseñanza de las ciencias desde una mirada de la didáctica de la Escuela Francesa

Barros-Martínez, J. F. (Juan Fernando) | 2014-05-12

In science teaching variety of knowledge takes part: that of sciences, that of the scientist, the academic, that of the professor, the daily one, that of the student. In this paper a journey for some models of constructivist’s focus is carried out, until arriving to the didactics of the French school, in an attempt to show the elements of the didactic situations of important development in mathematics teaching. The intention is to show that this didactics could be welcomed in the teaching of sciences, since its proposal offers to the process of teaching-learning and in particular to the ternary relationship professor, student and object of the knowledge elements for a didactic development that can guarantee the appropriation of the knowledge on the part of the student.

Remoción biológica de materia orgánica, nitrógeno y fósforo en un sistema tipo anaerobio-anóxico-aerobio.

González, M. (Maribel) | 2014-05-12

Experimental results from a series of biological unitary processes for the simultaneous removal of organic matter (OM), nitrogen (N) and phosphorus (P) are shown in this study. A synthetic substrate similar to a domestic wastewater of average concentration was used. The experimental development was made using an A2O system (anoxic-aerobic-anaerobic) performed in two phases. The preliminary stage lasted 60 days and included, besides the acclimatization of the biological sludge, the examination of polyurethane foam as a support medium in the aerobic phase. In the secondary stage, the stability was rapidly reached; this phase lasted 280 more days; a significant increase of the removal efficiencies was observed to be close to 92.5 % in organic matter, 87.7 % in nitrogen, and 83.5 % in phosphorus. Parameters such as dissolved oxygen (DO) and oxide reduction potential (ORP) were permanently monitored and maintained in values according to the requirements of the processes in each reactor. On the other hand, pH was measured to be higher than 7.2 units, ensuring the viability of the nitrification-denitrification processes. A hydraulic study using tracers was developed in order to find out the effect of the support medium on the hydraulic regimen of the aerobic reactor.

Características, dinámica y causas del movimiento en masa del Barrio El Socorro (31 de mayo de 2008) en Medellín

Aristizábal, E. (Edier) | 2014-05-12

The article presents the causes and dynamic of the mass movement which occurred on May 31, 2008 in the higher part of San Pedro settlement, called Las Peñitas, Medellín. This tragic event left 27 dead people, 16 injured people and 20 houses destroyed of El Socorro settlement. This event with Rosellón (1927), Media Luna (1954), Santo Domingo (1974), Villatina (1987) and El Barro (2005) represents one of the most tragic events in the Aburrá Valley history. For the characterization of the area of the event previous work from different recognized, prestigious institutions was used; for the characterization, description of the predominant dynamics of the event and its causes ground evidence collected on the terrain and visual inspection the same day when it occurred were used, so that it did not change due to proper rescue works. The data of rainfall hydrometeorological stations of Empresas Públicas de Medellín (EPM) and Colombian Institute of Hydrology, Meteorology and Environmental Studies (IDEAM) were used, with the purpose of evaluating the influence of rain like triggering element. The mass movement was classified as simple rotational landslide on NE direction, with a longitude around 60 m, which due to high saturation levels, it changed to an debris flow moving 140 m ahead on SE direction, and finally the mass turned NE. Triggering causes are associated to geomechanical properties of soil and antecedent rainfall of previous 15 days and very intense rainfall event during May 30, when 83.3 mm fell down for just 2 hours and 30 minutes along the central part of the valley.

Una metodología para valorar un callable bond

Grajales-Correa, C. A. (Carlos Alexánder) | 2014-05-12

In this paper the methodology employed for assessing a bond that includes a call option (callable bond) is given by the numeric implementation of Hull and White short rate model, which it is accomplished through an interest rates trinomial tree. It also presents an application for the case of the company Interconexión Eléctrica S. A. –ISA–, which has issued two callable bonds instruments. For the development of such application computer algorithms are implemented to value the two bonds of the company, and they also allow the structuring of a bond with a generic type call option included.

Información, conocimiento y desarrollo económico

Lochmüller, C. (Christian) | 2014-05-12

Production of information and knowledge is booming. Access to and availability of information and knowledge are better than ever before. However, we can observe companies and countries which use existent knowledge more effectively than others. This paper describes the role of information and knowledge in economic theory, discusses the difficulties of transferring knowledge and analyses the fact that in many cases created knowledge does not get introduced to markets. Innovation and entrepreneurship are the missing link that should be strengthened in order to transform knowledge into new products, processes, services, and markets. That is why changes are necessary within companies as well as in the education system in order to apply and commercialize more of the generated knowledge.

Calidad del agua de las Quebradas La Cristalina y La Risaralda, San Luis, Antioquia

Arango-Jaramillo, M. C. (María Cecilia) | 2014-05-12

The streams La Cristalina and La Risaralda are the water sources for the urban area of the Municipality of San Luis, Antioquia. The intention of this study was to develop a map of water quality that serves as base as comparison of the evolution of the streams and allows the high-priority destination of the resources of the Municipality in the improvement of those more critical sections. In order to determine the quality of the water, parameters and some characteristics of the stream that can alter the quality of the water were measured, like substrate of the bed, cover of banks, aquatic habitats, temperature, conductivity, oxygen, pH, coliforms, and aquatic macroinvertebrates. The indices calculated with base in the collected data were: BMWP, ASPT, ETP, Index of Diptera, and equity Index. With the data of the ASPT the map of water quality of both streams was elaborated. The streams are well oxygenated and the rocky conformation of its bed allows the diversity of aquatic macroinvertebrates, nevertheless, in some sections, they are subjected to contamination of domestic and farming origin, which limits their conditions of use.

Marcado con láser sobre cerámica vidriada por aporte superficial de un pigmento de cobalto

Gómez-Botero, M. A. (Maryory Astrid) | 2014-05-12

Laser materials processing has great application to industrial scale, to print graphic patterns on ceramics surfaces. The fast implementation of this process is due to the fact that, with respect to the conventional baking process, has advantages, such as: heat is concentrated only in the radiated zone that involves a smaller energy consumption without affecting significantly the rest of the piece, graphic patterns with of highly spatial resolution are obtained, it permits to introduce changes during the process without requiring long stops, and low or almost none generation of residues. In this study the results obtained from Nd:YAG (λ=1064 nm) laser glazing on the enameled surfaces of glazed tiles, which were previously covered with black of cobalt pigment, are presented. With the laser operating in continuous wave (CW), a series of lines were marked, whose width and depth showed a direct dependence with the variation in the power and scan speed of the laser beam on the surface of the glazed tile. Finally, these glazed lines were characterized by optical microscopy, energy dispersion spectroscopy (EDS), and X-ray diffraction (XRD).

Directrices para la construcción de artefactos de persistencia en el proceso de desarrollo de software

Quintero, J. B. (Juan Bernardo) | 2014-05-12

Data storage is a process required in almost every information system nowadays; the treatment given to databases during the software development can be a determining factor in order to achieve good performance of a resulting system. The accelerated technological evolution and the progress of the software enterprises have given rise to diverse modeling strategies and several data access techniques. This work explains the practical and conceptual references for the construction of products related to databases, the access techniques to them and the handling that so-called persistence artifacts have at an industrial level.

Relación de las curvas de energía específica y pendiente de fricción con las zonas de flujo libre en canales

Mejía-Garcés, F. J. (Francisco Jaime) | 2014-05-09

One objective of an introductory course of open-channel flow is the analysis of gradually varied flow profiles. This paper shows a teaching-learning strategy that might improve the university practices for teaching hydraulics. It is well known the depth-specific energy curve (y-E) for describing and interpreting open-channel flow hydraulics. It is proposed to complement that curve with the depth-energy slope curve (y-sf). By using a graphic comparison, it aims to illustrate the concepts of the subcritical (y>ycritical, v<vcritical), critical and supercritical flow concepts and, on the other hand, the subnormal (y>ynormal, v<vnormal), normal y supernormal flow concepts. This way, it is proposed to explain the behavior of the twelve possible gradually varied flow profiles.

Annual and diurnal cycles of the inverse relation between plant transpiration and carbon sequestration

Moreno-Ramírez, H. A. (Hernán Alonso) | 2014-05-09

El conocimiento de los ciclos biogeoquímicos y, en especial, de los balances de carbono es clave para la validación de los modelos de cambio global para el presente y el futuro cercano. Como consecuencia, en el mundo se estudian las fuentes y los sumideros de carbono. Uno de esos sumideros es la vegetación del planeta, que involucra los procesos de respiración y fotosíntesis y cuyo comportamiento se empieza a estudiar. Las tasas de captura del carbono están muy ligadas a la transpiración mediante un proceso de difusión molecular en los estomas, que puede registrarse por un sistema micrometeorológico de eddy covarianza. Este artículo explora los ciclos anuales y diurnos de los flujos netos de CO2 y calor latente de seis ecosistemas diferentes. Se desarrollan diversos análisis de escala temporal, basados en la física de la transpiración, y se halla una relación cuasilineal entre los flujos netos de calor latente y CO2, más fuerte en las áreas con mayor cobertura vegetal. La temporada del monzón norteamericano incrementa la captura de carbono y la relación entre la evapotranspiración y el intercambio de gas carbónico se mantiene en las diferentes escalas temporales analizadas (horas, días, meses).

Análisis de la ingeniería de requisitos orientada por aspectos según la industria del software

Londoño, L. F. (Luis Fernando) | 2014-05-09

Applying good practices to manage software requirements is a basic condition to obtain quality products. Therefore, it is important that software companies maintain a constant research around of new techniques and mechanisms to improve requirements activities such as elicitation, specification, and modeling. In this paper, we present a study of most representative aspect-oriented requirement approaches in order to analyze the way how these could support issues confronted by software companies during early stages of the lifecycle. Thus, we make a comparative analysis among approaches under criteria defined such as scope, traceability, requirements composition, conflict management, mapping, validation-verification, and scalability. Results achieved allowing us to know opportunities offered by aspect-oriented approaches so as to improve the requirement process.

Un método de ingeniería inversa de código JAVA hacia diagramas de secuencias de UML 2.0

Zapata-Jaramillo, C. M. (Carlos Mario) | 2014-05-09

Software reverse engineering seems to be the process for helping software quality assurance and documentation in applications with low-quality analysis and design models. It also helps for decreasing maintenance cost and time. Currently, some CASE tools and research proposals assist analysts to develop reverse engineering process with UML diagrams as a result (especially class and sequence diagram). Some of them have reached experimental phases. Some others are focused more on class diagram and less on sequence diagram. A third group of CASE tools and proposals obtains sequence diagram, but the resulting diagram lacks some of the elements of the UML 2.0 specification. In this paper, we propose a method for automating the conversion of JAVA code into UML 2.0 sequence diagram, by means of the application of transformation rules for converting code elements to the diagram elements. We also present an example of the method application through a prototype named UNC-Inversor.

Cómo llegan a la definición de la estrategia las empresas localizadas en el Valle de Aburrá

Ramos-Paniagua, A. (Alejandro) | 2014-05-09

This paper is focused on the understanding of the variables and determinants of the ideas about strategy and how to reach it, that were expressed by people who work in companies that are located in the Aburra Valley (Medellin, Colombia). The methodology used in the research had an exploratory character, focused on qualitative aspects and was conducted by the completion of a questionnaire with open questions, which final results and observations were afterwards analyzed. After the integration of the results, these were contrasted with recognized authors, such as, Igor Ansoff, Michael Porter, Alfred Chandler, Henry Mintzberg, Richard Whittington, to mention a few, in order to compare the results of the field research with the proposals of such management theory experts.

Control en cascada por métodos difusos

Grajales, J. D. (José David) | 2014-05-09

This article describes the development of a flow and level cascade control by diffuse methods, evaluating the Mamdami and Takagi-Sugeno control algorithms. They were implemented in the system for the ethanol manufacture. The algorithms were simulated with MATLAB 5.3 and developed in the graphical programming environment of LabVIEW 7.1, National Instruments.

Evaluación del riesgo de contaminación por metamidofos en la Microcuenca El Salto del Municipio de el Santuario, Antioquia

Ramírez, D. H. (David Horacio) | 2014-05-09

This investigation was done in El Salto watershed basin located in the municipality of El Santuario. It was examined the presence of Metamidofos in plants of cabbage, in soils, with risk of contamination in waters for the human consumption. The level of concentration of Metamidofos exceeded the maximum limits established by Codex Alimentarius. In the soil, remainders of the product were not found, but they were present in runoff and in two sites of the channel of the gorge, located upstream of the intake of the municipal water system. Metamidofos was not found in the water sample of intake nor in the distribution network of the municipal water system.