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DIALNET OAI Articles (538,205 recursos)
Dialnet (Difusión de Alertas en la Red) es una plataforma de recursos y servicios documentales, cuyo objetivo fundamental se centra en mejorar la visibilidad y el acceso a la literatura científica hispana a través de Internet.


Mostrando recursos 1 - 20 de 29,701

1. Construcción de un aplicativo para el control de activos tecnológicos al interior de una organización: beneficios y experiencias. - Jaramillo Arango, Adrián Alberto; Correa Henao, Gabriel Jaime
This paper shows the results of a casestudy which has been applied to both development and implementation of a software tool for management of technologic assets. The development of the methodology and its respective application has been implemented in "Fundación Universitaria Luis Amigó", according to its administrative structure model that aims to its recognition as high quality educational institution. The results of this study have demonstrated the advantages of automating various processes by means of software tools, which help to strengthen the quality management system. The article also shows a discussion on the strategy that supports the construction each organization,...

2. An academic value-added mathematical model for higher education in Colombia - Bogoya, José Daniel; Bogoya Ramírez, Johan Manuel
The concept of academic added-value can be associated with a variation in the cognitive development of students who complete an educational cycle at a given institution belonging to a reference universe, related to the tendency shown by all students in the aforementioned universe. Certain knowledge at the beginning and end of the cycle must be evaluated to estimate such variation. The pertinent literature states that learning is the result of students, teachers, and classmates' intellectual capacity, mainly within the family and an institution. This article proposes an academic value-added linear mathematical model representing a single student and sets of students in Colombia, grouped by institution,...

3. Towards a framework for deriving platform-independent model-driven software product lines - Paz, Andrés; Arboleda, Hugo
Model-driven software product lines (MD-SPLs) are created from domain models which are transformed, merged and composed with reusable core assets, until software products are produced. Model transformation chains (MTCs) must be specified to generate such MD-SPLs. This paper presents a framework for creating platform-independent MD-SPLs; such framework includes a domain specific language (DSL) for platform-independent MTC specification and facilities platform-specific MTC generation of several of the most used model transformation frameworks. The DSL also allows product line architects to compose generation taking the need for model transformation strategy and technology interoperability into account and specifying several types of variability involved...

4. Interfaz cerebro computador basado en señales EEG para el control de movimiento de una prótesis de mano usando ANFIS. - Bedoya Rojas, Alexandra; Giraldo Leiva, Jessica; Torres Pardo, Ingrid Durley; Becerra, Miguel A.
A large number of people in the world who have amputated limbs that are usually replaced by mechanical prostheses. Moreover, electromechanical prostheses have been gaining strength and are supported by different types of interfaces as brain interfaces computer that improve the functionality of these, despite show representative results for the control of prostheses, it is still an open field research that seeks to improve its effectiveness and efficiency. In this paper, we present a methodology for classification of electroencephalographic signals (EEG) to control movement of a prosthetic hand, based on the adaptive neurofuzzy inference system (ANFIS) applied to features derived from the wavelet...

5. Using radio frequency and ultrasonic antennas for inspecting pin-type insulators on medium-voltage overhead distribution lines - Lefort Borges, Cícero; Barreira Martinez, Manuel Luís
This paper summarises the activities undertaken when using antennas (ultrasound and radiofrequency) for identifying insulators in pre-failure state by detecting the noise emitted by the distribution line and correlating this with these insulators (porcelain pin type) dielectric breakdown. This has led to developing low-cost maintenance procedures and providing support and criteria for engineer-ing decisions regarding replacing these insulators. The technique used two detectors; a radio frequency detector was used in a first investigation of a particular distribution line, set to 40 MHz and installed on the roof of a moving vehicle. The ultrasound detector was used for inspecting (phases A,...

6. An optimal algorithm for estimating angular speed using incremental encoders - Rairán Antolines, José Danilo
This paper proposes a new algorithm using signals from an incremental encoder for estimating a rotating shaft's speed. This algorithm eliminated the oscillations appearing in classical fixed-time and fixed-space algorithms, even when speed was constant. A fixed-time algorithm measures angular displacement at fixed-time intervals, while a fixed-space algorithm measures time every fixed-angular displacement. Time and displacement measurements were used to generate estimations for speed. The new algorithm generated a unique value for estimating speed due to synchronising encoder pulses and a signal formed by impulses every time increase (delta). A first modification of the proposed algorithm was defined, resulting in...

7. Developing high-performance concrete incorporating highly-reactive rice husk ash - Salas, Andrés; Delvasto, S.; Mejía de Gutiérrez, R.
The aim of this study is to present results of an investigation about the developing of a highperformance concrete (HPC) using a highly reactive pozzolan made from chemically treated rice husk ash (ChRHA) prepared by a chemical-thermal attack to the rice husk. This particular rice husk ash (RHA) consists of 99% of silica, highly amorphous, white in color and of greater pozzolanic activity than the silica fume and another rice husk ash prepared with only by a thermal treatment. The results of the physical, chemical and mineralogical characteristics of ChRHA are analyzed. In this study, the compressive strength, flexural strength,...

8. A proposal of t-learning: using artificial intelligence planning and ontological reasoning. - Torres Pardo, Ingrid Durley; Guzmán Luna, Jaime Alberto; Becerra, Miguel A.
This paper focuses on the proposition of how to use the techniques of Planning in Artificial Intelligence in conjunction with Ontological Reasoning in t-learning environments, in order to I) achieve automating processes such as, the presentation and adaption of the Learning Objects or the educational applications (composed of Learning Object); II) address the differences of terms and meanings that can occur between multiple viewers, finally, III) allow the reuse of learning objects in different contexts.

9. Urban air pollution in school-related microenvironments in Bogota, Colombia - Franco, Juan Felipe; Rojas, Néstor Yesid; Sarmiento, Olga Lucía; Behrentz, Eduardo
Particle-related pollution (PM10, PM2.5 and soot) was measured in both indoor and outdoor microenvironments at four public elemen-tary schools in Bogota, Colombia. Three of these schools were located alongside major urban roads in which different types of public transit systems are used (bus rapid transit system and conventional transit buses). The fourth school was located on a non-congested road (background school). Pollutant levels at schools situated on major-roads were higher than those found at the low-congestion-road school. Outdoor black carbon daily mean concentrations at the schools located near major roads were up to six times higher than those recorded at...

10. Degradación de suelos ante tensión de corte cíclica. - Galindo Aires, Rubén Ángel
The article describes the phenomenon of degradation and dependencies with the variables involved in the dynamic problem are proposed, considering the mathematical formulation that characterizes the cumulative deformation and pore pressure generation associated with cyclical phenomenon. First, the necessary theoretical framework for the proper study of dynamic phenomena associated with the process of cyclic shear load is raised. Then, a new concept called "limit cycle" that serves as a reference for monitoring soil degradation is introduced. Finally, the fundamental variables involved in the study problem are identified and is raised, based on an earlier test campaign of an available research, the...

11. Ceramic bricks made from municipal solid waste incineration-derived clay and ashes: a quality study - García Ubaque, Cesar Augusto; González Hässig, Andrés; Vaca Bohórquez, Martha Lucía
This paper presents analytical data from tests on bricks made from different clay/ash mixtures. The ashes used were obtained from a Hoffmann-type brick-making furnace equipped for coal and municipal solid waste co-firing. The bricks were physically and chemi-cally characterised and their quality was determined by porosimetry, water absorption, breaking load and tensile strength tests. Brick loading capacity increased by up to 10% with ash mixtures and decreased at higher percentages, whereas water absorption in-creased brick loading capacity for all mixtures. This study showed that clay/ash bricks complied with all the quality standards re-quired in Colombia.

12. Adaptación del algoritmo genético para la creación de árboles de enrutamiento en una red de sensores inalámbrica. - Rodríguez Vivas, Ángela María; Corrales Muñoz, Juan Carlos
Routing is an impact factor for wireless sensor networks (WSN) longevity; in applications like precision agriculture is essential to preserve the sensor nodes lifetime because deployment field (hilly land) location usually does not allow to recharge their batteries. In this paper a genetic algorithm adaptation in order to generate routing trees for WSN in the context of precision agriculture is proposed. The adaptation consists of including in the algorithm parameters from such a context, and of determining by means of experimentation the selection method that is best suited to the solution according to the convergence time of the algorithm.

13. Total organic carbon removal from a chemical lab's wastewater using Fenton's reagent - Martínez Avila, Oscar Mauricio; Ramírez Franco, José Herney; Toledo Reyes, Magda Lorena
Treating industrial wastewater represents a serious problem nowadays; it requires a strong understanding of the particular systems and (in most of cases) ad hoc solutions. This work describes the use of Fenton's reagent (reaction between H2O2 and Fe(II)) for re-moving total organic carbon (TOC) from a particular chemical laboratory's lab-scale batch reactor wastewater. Some operating variables (hydrogen peroxide and ferrous ion concentration, temperature and pH) were evaluated regarding final TOC removal. An economic optimisation was made by means of a second order polynomial model representing these variables' behaviour regarding TOC removal (0.94 R2). The highest experimentally reached TOC removal was...

14. A review of conceptual transparency in US and Colombian seismic design building codes - Carrillo León, Wílmer Julián; Blandón Valencia, John; Rubiano Fonseca, Astrid
The goal of re-examinination of seismic design codes is aimed at making their provisions as transparent as possible for users so that the design would be clear and enriching for structural engineers. This paper presents a transparency evaluation of the codes currently being used in the USA and Colombia for seismic design of buildings. It is demonstrated that the procedures used in most codes do not offer a clear view of buildings' seismic response assessment. The Colombian code should become as conceptually transparent as possible when defining strength modification factors and assessing maximum lateral displacement. In addition, at least two limit states (service and life...

15. Una mirada al análisis de redes de transporte en Cuba desde el punto de vista de los datos. - Sánchez Ansola, Eduardo; Sánchez Jiménez, Laura; de Armas García, Carlos José
At present times, most of the activities of human society are in a process of computerization. This means that public services such as hospitals, fire departments, police, transport companies, among others, can use these processes in order to improve the quality of services they provide. Among the main tools that support the computerization of society are Geographic Information Systems (GIS) and Spatial Data Infrastructures (SDI) that support decision making for the solution of several problems using existing spatial data. Developing countries, such as Cuba, are not exempt from the computerization of their society, so this paper presents a study of current data...

16. AlN film deposition as a semiconductor device - Caicedo Angulo, Julio César; Pérez Taborda, Jaime Andrés; Aperador Chaparro, Willian
AlN films were deposited by pulsed laser deposition (PLD) using an Nd: YAG laser (ë = 1064 nm). The films were deposited in a nitrogen atmosphere as working gas; the cathode was an aluminium high purity (99.99%) target. The films were deposited using 7 J/cm2 laser fluence for 10 minutes on silicon (100) substrates. The working pressure was 9x10-3 mbar and the substrate temperature was varied from 200°C to 630°C. The thickness measured by profilometer was 150 nm for all films. Moreover, surface acoustic wave (SAW) devices with a Mo/AlN/Si configuration have been fabricated using AlN-buffer and Mo Channel. The films' morphology and composition...

17. Seguridad en activos de información humanos. - Cadavid Aguirre, Jorge Mario

18. Iniciativas para el cambio. - Defrancisco Larrañaga, César Alfonso; Ortiz López, Christian Camilo

19. Characterising μ-AlTiN coating and assessing its performance during Ti-6Al-4V milling - Moreno Tellez, Carlos Mauricio; Sánchez, José Manuel; Higuera Cobos, Oscar Fabián
This study investigated the mechanical properties and performance of μ-AlTiN coating deposited by PVD cathodic arc technique for a specific Al0, 67Ti0, 33N composition deposited on a WC-Co and AISI D2 steel substrate. The structure of the coating was analysed using SEM, EDAX, XRD, AFM and TEM. Nano indentation measurements were used for analysing mechanical properties; the coating's performance was evaluated during the milling of a titanium alloy (Ti6Al4V). The TiN film was initially deposited to improve adhesion between coating and substrate, where columnar grains ranging in size from 200 to 500 nm were observed having NaCl-type structure. μ-AlTiN grain...

20. LDPE and PP thermal diffusivity in molten state - Yánez, Genhli; Rodríguez Pérez, Miguel Angel; Almanza, Ovidio
Experimental results are reported for measuring the thermal diffusivity of two polymer species: low density polyethylene (LDPE) and polypropylene (PP). Measurements were taken in unsteady state heat flow conditions around the materials' melting temperature, using a device specially constructed for this purpose. The experimental results for the sample' temperature profile (temperature gradient product) were adjusted with the theoretical results obtained by solving the heat conduction equation. Diffusivity values were . for LDPE and for PP. This was pioneering work in measuring this property at high tem-peratures in non-stationary state heat flow conditions and should be useful in the search for...

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