Tecnura

24-37

Authors: Helbert Eduardo Espitia Cüchango, Jorge Iván Sofrony Esmeral

In this document, it will be introduced the proposal for optimization algorithm based on particle swarms vorticity features, where a search group is considered through the association to the mid point of the swarm and an individual search is given for the best position of each individual. The search group seeks to achieve the convergence of the whole swarm, whereas the individual search allows better exploration in pursuant of space. The algorithm has convergence and exploration behavior given by the selected model which is based on the behavior of a swarm of individuals. For establishing the algorithm performance, a set of test functions in two dimensions is used.

53-64

Authors: Alejandro Garcés Ruiz, Carlos Adrián Correa Flórez, Alejandro Sánchez Salcedo

This paper presents an algorithm for the optimal operation of distributed energy storage units from perspective of active potential lost. An exact model based on Lagrange relaxation is proposed. Simulation results on the IEEE 37-bus test feeder demonstrate that energy storage system can be used for minimizing transmission losses in a distribution system by reshaping the load curve. The main contribution of this approach is the objective function and the optimization algorithm, Lagrange multipliers are used for determining optimal placement and sizing of the energy storage units. A discussion about the impact of energy storage units on the distribution planning is also presented.

78-89

Authors: Sergio Andrés Vanegas Herrera, Gustavo Chio Cho

The reliability index β is a parameter used to estimate the safety of a structure or an element during the design stage or service. This parameter defined in other codes in the world (European Committee for Standardisation (Eurocode), EN 1990:2002; American Association of State Highway and Transportation Officials (AASHTO), 2012), is not specified in the Colombian Code of Bridges Seismic Design (CCDSP-95) (1995). In this paper, it will be presented a study on the estimation of the reliability index β of the interior and exterior girders of a beam and slab bridge with reinforced concrete, 30 m in length, simply supported and designed according to the CCDSP-95. In the evaluation of the resistant moments, there were considered properties of materials using a normal distribution, and moreover, a Monte Carlo simulation was used to estimate load effect of moment at mid-span of the live load

103-113

Authors: Luz Amparo Quintero Ortiz, Ricardo Alfredo Cruz Hernández, Deyci Yamile Peña Santos

The purpose of this study is to determine correlations among content of concrete water, compressive resistance and Ultrasonic Pulse Velocity (UPV). Cylindrical concrete specimens, 200 mm long and 100 mm in diameter made from a mixture of Portland cement type I, and a water/cement ratio (w/c) 0.5, have been studied. The curing of the specimens was performed under standardized conditions and indoor environmental conditions. It determines the water content in each specimen by difference in weight and subjecting them to UPV tests and to compressive resistance test during the first 28 days after the setting. The results show a model of logarithmic type that describes the relationship between the compressive strength with the water content of concrete and the UPV during the curing stages proposed.

126-138

Authors: Carlos Alberto Ardila Albarracín, Francisco José Pino Correa, César Jesús Pardo Calvache, Luis Merchán Paredes

The small software development companies have difficulties in adopting practices about quantitative process management offered by reference models such as CMMI-DEV or ISO/IEC 15504 because it generates expensive investments in long-term periods of time. However, if they do not incorporate at least the essential practices, they won’t be able to obtain processes with less variability in its performance and that can be statistically under control which directly impacts the projects results because they would allow making better estimates. In this article, it is presented a general proposal of a framework for quantitative process management in very small entities (MaTGeC) that offers a guide to monitor and assess specific processes selected by the organization. Moreover, it is indicated the components that conform it, along with the practices, activities, roles and essential work products for that this kind of organizations to incorporate the quantitative management fundamentals in their more critical tasks.

27-37

Authors: Nelson Enrique Vera Parra, Danilo Alfonso López, Héctor Cristyan Manta Caro

Currently, mobile networks and next generation wireless networks such as, IPv6 low-power Wireless Personal Area networks 6LoWPAN, wireless sensor networks and hierarchical mobile networks in IPv6, are under rigorous research and development, thereforethose networks represent the next step in the evolution of the Machine-to-Machine M2M networks, while supporting broadband access for the next generation of intelligent systems, technologies and future Internet. These next generation networks impose restrictions on the processing power, bandwidth and energy resources, which represents a major constraint in the implementation of security mechanisms. In this regard, in recent years there have been various proposals for key management, digital signature procedures and data encryption based on elliptic and hyper-elliptic curves, to achieve levels of safety equivalent to convenWLRQDO DOJRULWKPV EDVHG RQ 'LI¿H+HOOPDQ DQG Rivest-Shamir-Adleman RSA, but reducing the key length and thus the computational and network resources. This paper reviews algorithms based on Elliptic Curves Cryptography ECC and their application to IPv6-enabled new generation wireless networks. This paper also describes a simulation test-bed for the evaluation of ECC, where we compare computational resources required and limitations for lightweight security mechanisms in se

53-63

Authors: Jesús D. González Llorente, Gustavo A. Puerto Leguizamón

CubeSats are small satellites that due to their size restriction have photovoltaic cells placed on theirs surface as the only energy source. The purpose of this work is to estimate the maximum amount of power that can be obtained from these solar cells, so that an energy balance can be made during the design of space mission with this kind of satellites. In the analyzed scenario, a CubeSat of 10cm x 10cm x 10cm (1U) has always a face oriented toward the Earth. Cosine loss and the temperature variation due to satellite orbit are considered. For the estimation we use a mathematical model of the solar cells, which is also used to estimate the maximum power point according to the incidence angle of the solar radiation and the temperature on a low orbit around the Earth. The results show the variation of the maximum electric power supplied by the panels on the illuminated portion of the orbit, without considering the Earth’s albedo. Apart from the power, the current -voltage curves are estimated for different locations over the CubeSat’s orbit.

76-90

Authors: Andrés Jaramillo Ortiz, Robinson Jiménez M, Olga Lucía Ramos

This paper details implementation of an artificial vision system through digital image processing, which allows automation of the quality control process. The prototype was implemented in a conveyor belt segment and was designed to discern the quality of two different industrial shapes, with a sensibility of +/- 0,1 mm and a speed rate of 1400 shapes per hour, identifying which pieces are within manufacture quality requirements. This work is divided in three main sections: hardware, electronic control and software.

103-119

Authors: Luis Alberto Paredes Chérrez, Óscar Javier Reyes Ortiz, Javier Fernando Camacho Tauta

Mechanic characterization of asphalt mixtures uses to be expensive and time consuming. How- ever, some researches try to correlate such prop- erties by simple, fast and less expensive tests. The main goal of this investigation consisted into establish the viability of use the simply sup- ported semicircular beam (SCB) to characterize dense asphalt mixtures designed under speci- fications of the Instituto de Desarrollo Urbano (IDU) and the Instituto Nacional de Vías (In- vias). The study started with the production of SCB specimens using different materials (soil aggregate, asphalt, asphaltite, reclaimed asphalt pavement and lime) and compaction techniques (vibration and gyratory compaction). The SCB tests were carried at a velocity of 1mm/min and 15ºC of temperature. From these tests, different parameters were obtained based on the definition in the Fénix test (maximum load, displacement at maximum loading, energy released during the cracking process, traction stiffness index and te- nacity index). From the results, it was found that the SCB tests were useful as a tool to character- ize the mechanical properties of the asphalt mix- tures. This conclusion is applicable for all kind of mixtures tested, ageing periods, compaction level and filler content.

134-153

Authors: Hernán Porras Díaz, Jhon Jairo Cáceres Jiménez, Elver Omar Gallo Lancheros

The state of the art of the processing methods for TLS (terrestrial laser scanner) digital point clouds is shown in this paper. The TLS is an instrument able to capture topographic and geometric information of any structure at millimeter accuracy. Also, in some cases, they capture radiometric information of the scanned objects. The collected information is represented by point clouds that are used on a wide range of applications such as planning of urban development, structural analysis, erosion and deforestation modeling, cultural heritage preservation and virtual navigation. The purpose of this work is to offer a review of the state of the art on the methods used through the several steps of the point cloud processing workflow: relative and absolute registration, segmentation, classification and three dimensional modeling.

20-35

Authors: Maira Cecilia Gasca Mantilla, Luis Leonardo Camargo Ariza, Byron Medina Delgado

This paper presents: the evolution of mobile telephony services in Latin America contextualized in different technology generations, the features of software for mobile devices, and proposes a method for developing mobile applications in Latin America. This method is based on the conceptualization of contemporary telecommunications technologies and the agile software development methodologies. The main objective of this method is to facilitate the creation and evaluation of new applications and services. The method is developed in five steps: the analysis stage, the requirements is obtained and classified and the service is customize; the design stage, in this stage is defined the technological and the solution is structured by some chart or diagram; the development stage, the design is implemented in a software product; the performance test stage, the application is emulates and simulates to adjusting details in the product, the software is installs in real equipment and is evaluated the performance and success; the delivery stage, the distribution channel of the application is defined, in order to adapt the application at the same. Furthermore, the paper presents the results of developing a m-health service in Android and J2ME using the proposed method, service for patients who need or wish to have regular monitoring of measurements of blood pressure and glucose. The service has a satisfactory evaluation with test users.

48-61

Authors: Carlos Alberto Hidalgo Mora, Nelson Leonardo Díaz Aldana, César Leonardo Trujillo Rodríguez

During last two decades, several technologies have developed and improved the high voltage direct current systems. The technological growth in power electronics converters has led to increase flexibility and modularity for interconnections of alternating current and direct current systems. In this sense, high voltage direct current system based on voltage source converters appear as feasible and flexible technology when active and reactive power flow have to be regulated between different power grids. Therefore, for an adequate operation, one of the major challenges is to regulate the direct current voltage and the reactive power flow between the alternating current system and the voltage source converter at the rectifier station. In this document, several methodologies will be explored for modeling, identifying, and designing controllers to regulate the direct current voltage at the common bus, and reactive power flow. In particular, linear techniques such as feedback states are used for the design of controllers. Finally, practical results will be presented on a physical voltage source converter prototype.

71-88

Authors: Mirna Jirón Popova

This article presents part of the results of the research work titled"Technological formation in Colombia in the public university field", particularly at Universidad Distrital Francisco José de Caldas, which was one of the observed institutions. Consequently, we present the findings related to the events that take place from the moment in which Technological Faculty is institutionalized, aiming at offering Technological Higher Education to disadvantaged sectors from the population at Distrito Capital. Special emphasis is made on aspects related to the tensions among resisting or adapting to the regulations of the control mechanisms; conjunction that lastly determines that this faculty would transform its original proposal of Technological Education by Cycles, towards an Engineers Formation by Cycles and, afterwards, to Engineers Formation by Propaedeutic Cycles.

103-114

Authors: scar Ignacio Sánchez, César Alberto Torres, Francisco Santamaría

In order to design an efficient protection system of structures against lightning, a risk assessment shall be made, and damages and losses resulting from that event must be identified. In this sense, the is-sues described in the standard NTC 4552 or the IEC 62305 to perform the risk assessment must be taken into account, and thus evaluate whether a protection system against lightning is needed or if the existing lightning protection system needs modifications. The Colombian standard NTC 4552 "Protection against lightning" is based on the principles described in IEC 62305, published in 2006. However, in the IEC 62305 (2010) changes were made, which significantly change the risk assessment and can generate an incorrect analysis for the Colombian case; in addition, several research results obtained in Colombian and other tropical countries have been incorporated in the NTC 4252, which has led some of the parameters used in the analysis and design of lightning protection systems are different from those used in international standards.

127-142

Authors: Vicente García Díaz, Edward Rolando Núñez Valdez, Jordán Pascual Espada, Cristina Pelayo García Bustelo, Juan Manuel Cueva Lovelle, Carlos Enrique Montenegro Marín

The software crisis is a concept that has started to be used in 1968, at the first conference organized by the North Atlantic Treaty Organization (NATO) on software development. There, Edsger Dijkstra criticized that projects were not completed in compliance with the classic triple constraint of project management (scope, time and cost), since most of them do not reach the expected requirements, are delivered out of time or exceeds the expected cost. Unfortunately, the current reality is that while there have been proposed new methodologies aimed at solving the usual problems related to software development, there is still no reliable method to estimate the development of computer systems. This work introduces the Model-Driven Engineering approach that, according to the experts, will help to solve many of the problems that thousands of software development teams have daily worldwide.

22-33

Authors: Lorena Cardona Rendón, Paula Andrea Ortiz Valencia, Juan Sebastián Botero Valencia

In this paper presents the development of a navigation system to estimate the position, velocity and orientation of a pool cleaner robot to be automated. We employ the weighted least-square technique for the design of the navigation system, which combines the noisy measurements of a triaxial accelerometer and a gyroscope with the solution to the differential equations that describe the robot's movement. The navigation system was tested using a (Simulink-based) model of the robot obtained from a tri-dimensional representation (built with CAD software – Autodesk Inventor). The final part of the paper presents the results and draws some conclusions about the feasibility of implementing the navigation system in the automation of a swimming-pool cleaner robot.

47-61

Authors: Sergio A. Rojas

Assessment of student knowledge in Learning Management Systems such as Moodle is mostly conducted using close-ended questions (e.g. multiple- choice) whose answers are straightforward to grade without human intervention. FILL-INTHE- BLANK tests are usually more challenging since they require test-takers to recall concepts and associations not available in the statement of the question itself (no choices or hints are given). Automatic assessment of the latter currently requires the test-taker to give a verbatim answer, that is, free of spelling or typographical mistakes. In this paper, we consider an adapted version of a classical text-matching algorithm that may prevent wrong grading in automatic assessment of FILL-IN-THE-BLANK questions whenever irregular (similar but not exact) answers occur due to such types of error. The technique was tested in two scenarios. In the first scenario, misspelled single-word answers to an Internet security questionnaire were correctly recognized within a two letter editing tolerance (achieving 99 % accuracy). The second scenario involved short-open answers to computer programming quizzes (i.e. small blocks of code) requiring a structure that conforms to the syntactic rules of the programming language. Twenty-one real-world answers written up by students, taking a computer programming course, were assessed by the method. This assessment addressed the lack of precision in terms of programmer-style artifacts (such as unfamiliar variable or function nomenclature) and uses an admissible tolerance of up to 20 % letter-level typos. These scores were satisfactory corroborated by a human expert. Additional findings and potential enhancements to the technique are also discussed.

77-93

Authors: Alejandro Castillo Ramírez, Fernando Villada Duque, Jaime Alejandro Valencia Velásquez

Solar- and wind power are the two major natural sources of intermittent power in the world. The combination of these sources has proved to be a suitable combination to maximize system reliability. A chronological methodology based on Hongxing and Diaf techniques for optimal sizing of a Photovoltaic Wind Hybrid System (HPWS) (using batteries for energy storage) is presented. Accordingly, the purpose of this work is to help to promote the hybrid power system concept through a fully theoretical point of view. The model can be used to optimize the system configuration, minimizing Loss of Power Supply Probability (LPSP) and Annualized Cost of the System (ACS). The proposed methodology was used to design an isolated HPWS that meets the energy demand of 49 users at Ishiruwo settlement (located in the municipality of Uribia, State of La Guajira – Colombia). Results show that there is an inversely proportional behavior between the two objectives under evaluation. Likewise, the chosen solution with low cost and high reliability suggests that it is better to use a fully Photovoltaic System (PV), since wind-turbine cost is very high. Finally, it is clear that the cost of isolated systems has begun to gain importance due to its competitiveness when compared to other types of generation such as diesel, although more than 50% of its value lies in batteries and other components.

110-127

Authors: Mónica Sánchez, Carlos Arturo Lozano Moncada, Diego Manotas

This paper presents a financial risk assessment model for the electrical-energy-sale process trough long-term bilateral contracts. The volatility exhibited by spot prices of electricity in Colombia constitutes one of the aspects of big influence in financial risk assessment within the electrical sector, where weather conditions are fundamental in the consolidation of electricity prices in a country whose major generation source is hydroelectricity. Moreover, in this paper, a case study is introduced from the perspective of one of the electricity market agents, namely the generator. The model is developed by means of probability-distribution definitions that represent input variables. Monte Carlo simulation methods were applied together with the analysis of robust risk indicators VaR (Value at Risk) and CVaR (Conditional Value at Risk), over a given time horizon and also considering different scenarios. This provides proper quantitative arguments for more detailed decision-making processes. Once the historic series of spot prices and contracts are analyzed and the analysis scenario has been deployed together with its corresponding financial risk assessment, a contracting optimal portfolio scheme (spot and bilateral contracts) is proposed based on the riskaversion level of the generator that supports the decision-making process.

138-151

Authors: Hernán Paz Penagos, María Bohórquez, Daniel Rodríguez, Danny Maldonado, Claudia Sánchez, Cesar Galarza

Mobile cellular communication companies in Colombia require more spectrum resources to expand their portfolio of services. However, additional frequency bands for that particular purpose are scarce, yet it is well known that there are many underutilized licensed bands. Therefore new radio technologies are being studied in order to solve this problem, e.g. Software Defined Radio SDR [1] Cognitive Radio CR [2] and Dynamic Spectrum Access DSA [3]. These strategies recommend mobility across the radio spectrum to meet various needs and achieve greater efficiency when managing such a scarce resource. In this context, a case study is presented in an attempt to examine the requirements that must be met for the implementation of cognitive radio networks in Bogota. The case study includes evaluation for the possibility of migration from cellular communications to cognitive radio since the bands assigned to Ultra-High Frequency UHF television offer possible free-of-interference coexistence between the two services (i.e. Cellular and TV). The study shows feasibility to migration; however, the implementations of cognitive radio need availability of hardware, software and flexible radio platforms.

165-180

Authors: Fabinton Sotelo, Mario Fernando Solarte

This paper gathers the findings of a detailed study on different technologies used to integrate web resources, such as electronic learning services provided by third parties, into a platform belonging to learning management system. LRN (at Universidad del Cauca). Additionally, a case study conducted in a rural school (in Cauca - Colombia) is reported in order to assess the performance of these technologies. The result of this publication represents a starting point to propose a framework (at an architectural level) for the integration of third-party learning services into the platform, which is one of the main objectives of the project.

197-199

Authors: Rubén Darío Bonilla Isaza

Sin duda alguna, cuando se habla de estrategias de desarrollo empresarial se encontrarán muchos libros al respecto, como también ocurre cuando de temas de innovación se trata. Sin embargo, son pocos los libros que tratan en conjunto los temas de innovación y empresas. El libro del profesor Rodrigo Varela, titulado Innovación empresarial. Arte y ciencia en la creación de empresas, presenta un análisis interesante sobre las diferentes alternativas de desenvolvimiento que debe tener todo cultor empresarial para un buen desarrollo del plan de empresa, haciendo énfasis en diversas fuentes de enriquecimiento y aprovisionamiento de recursos innovadores en la conceptualización y elaboración de cada una de sus etapas.