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Search Results: 1 - 10 of 211304 matches for " Jhon Jairo Galvis López "
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Control difuso para la corrección activa del factor de potencia
Galvis López,Jhon Jairo; Hernández Suárez,César Augusto; Martínez Sarmiento,Fredy Hernán;
Ingeniería y Desarrollo , 2011,
Abstract: the harmonic distortion introduced to the power grid by the massive use of low-power electronic equipment, is currently a major global problem of quality and efficiency of the network. the nonlinear characteristic of these devices produces large harmonic currents, which generate heat, faults and over current in a system designed for 60 hz. traditional solutions based on passive filters not only fail to solve the problem completely, but are to be bulky and expensive. active solutions, on the other hand, require the use of high performance control schemes, given the need to rebuild the current wave while output regulation is made, all at a much higher rate than that of network. in this sense, we present here a proposal for a scheme based on fuzzy logic control for active correction of power factor on a dc/dc boost converter. the structure and design are raised according to the operational and performance requirements for a typical medium power application. the final performance is verified by tests on a laboratory prototype, assessing and analyzing the behavior to changes in input voltage. the results show a significant reduction in harmonic content (pf = 0.924, thd = 21.2%), and high dynamic response around the operating point (response times below 100 ms).
Control difuso para la corrección activa del factor de potencia
Jhon Jairo Galvis López,César Augusto Hernández Suárez,Fredy Hernán Martínez Sarmiento
Ingeniería y Desarrollo , 2011,
Abstract: La distorsión armónica que se introduce a la red eléctrica de potencia por el uso masivo de equipo electrónico de baja potencia es actualmente un gran problema de calidad y eficiencia de la red a nivel mundial. La característica no lineal de estos equipos produce grandes armónicos de corriente que generan calentamientos, fallas y sobrecorrientes cuando circulan en un sistema dise ado para 60 Hz. Las soluciones tradicionales basadas en filtros pasivos no logran resolver completamente el problema, si bien dise arlas a frecuencias de red y potencia del equipo resulta voluminoso y costoso. Por otro lado, las soluciones activas exigen el uso de esquemas de control de alto desempe o, dada la necesidad de reconstrucción de la onda de corriente mientras se realiza regulación de salida, todo ello a una velocidad muy superior a la de la red. En este sentido, se presenta aquí una propuesta de esquema de control basado en lógica difusa para la corrección activa del factor de potencia sobre un convertidor DC/DC tipo boost. La estructura y dise o se plantean de acuerdo a las necesidades de operación y desempe o para una aplicación típica de media potencia. El desempe o final se verifica con base en pruebas sobre un prototipo de laboratorio, evaluando y analizando el comportamiento frente a cambios en el voltaje de entrada. Los resultados demuestran una significativa reducción en el contenido armónico (PF = 0.924, THD = 21.2%), y una gran respuesta dinámica alrededor del punto de operación (tiempos de respuesta inferiores a los 100 ms).
DIAGNóSTICO Y ANáLISIS DE ALGUNAS CAUSAS QUE DIFICULTAN EL APRENDIZAJE DEL ALGEBRA LINEAL EN ESTUDIANTES DE INGENIERíA
VIVIAN LIBETH UZURIAGA LóPEZ,JHON JAIRO ARIAS MENDOZA,DEIBYS GILDARO MANCO SILVA
Scientia Et Technica , 2010,
Abstract: En este artículo se presentan los resultados del diagnóstico y análisis de algunas causas que obstaculizan el aprendizaje del álgebra Lineal en los estudiantes de ingeniería de la Universidad Tecnológica de Pereira. Igualmente pretende identificar la importancia que se le da a la asignatura dentro de los programas de ingeniería, mediante encuestas que se realizaron a los profesores que orientan diferentes asignaturas de matemáticas como a los directores de los diferentes programas. Además se presentan conclusiones y recomendaciones acerca del estudio.
CONOCIMIENTOS, ACTITUDES Y PRáCTICAS ALIMENTARIAS EN PACIENTES DIAGNOSTICADOS CON VIH EN TRATAMIENTO FARMACOLóGICO
Bejarano-Roncancio,Jhon Jairo; Martha Eugenia,Ramírez; Saurith-López,Valerín; Sussman-Pe?a,Otto Alberto;
Revista Facultad de Medicina de la Universidad Nacional de Colombia , 2011,
Abstract: background. research related to nutritional habits during the asymptomatic phase of hiv has not been well documented or is very scarce; this would include understanding the importance of nutritional status regarding disease progression and that suitable nutritional status may slow transition to symptomatic stages or aids stage. no studies have yet been carried out in colombia describing nutritional habits in hiv-positive patients who have been receiving pharmacological treatment; no records have thus been kept and no advances have been made regarding this topic. objective. describing nutritional knowledge, attitudes and practice in asymptomatic patients diagnosed as suffering from clinical phase hiv infection receiving pharmacological treatment. materials and methods. a descriptive exploratory study was carried out using a care and prevention (cap)-based approach; the survey was voluntarily filled out by 108 patients who were attending outpatient consultation in two private institutions in bogotá. results. three components were analysed in the 108 surveys. knowledge. 58.7% of the patients referred to having received information about what their diet should have been like; 32.3% had their diet supplied by a nutritionist. fibre was the main component taken into account when choosing food (65%) and protein was considered to be the most beneficial nutrient (52%). attitude: 61.8% of the patients stated that their diagnosis hampered selecting and buying food due to a lack of information. appetite had not undergone changes in 49.5% of the participants following reflecting on their diagnosis. practice. 75% of the patients recognised the importance of consuming nutritional supplements and complements; however, only 35.7% of them took them. when buying industrialised/processed food, 66.4% of the patients verified the products' expiry date and/or nutritional data on the label. conclusions. the food customarily consumed by the patients was that forming part of the average colom
Nutritional knowledges, attitudes and practices in HIV patients who were receiving pharmacological treatment CONOCIMIENTOS, ACTITUDES Y PRáCTICAS ALIMENTARIAS EN PACIENTES DIAGNOSTICADOS CON VIH EN TRATAMIENTO FARMACOLóGICO
Jhon Jairo Bejarano-Roncancio,Ramírez Martha Eugenia,Valerín Saurith-López,Otto Alberto Sussman-Pe?a
Revista Facultad de Medicina de la Universidad Nacional de Colombia , 2011,
Abstract: Background. Research related to nutritional habits during the asymptomatic phase of HIV has not been well documented or is very scarce; this would include understanding the importance of nutritional status regarding disease progression and that suitable nutritional status may slow transition to symptomatic stages or AIDS stage. No studies have yet been carried out in Colombia describing nutritional habits in HIV-positive patients who have been receiving pharmacological treatment; no records have thus been kept and no advances have been made regarding this topic. Objective. Describing nutritional knowledge, attitudes and practice in asymptomatic patients diagnosed as suffering from clinical phase HIV infection receiving pharmacological treatment. Materials and methods. A descriptive exploratory study was carried out using a care and prevention (CAP)-based approach; the survey was voluntarily filled out by 108 patients who were attending outpatient consultation in two private institutions in Bogotá. Results. Three components were analysed in the 108 surveys. Knowledge. 58.7% of the patients referred to having received information about what their diet should have been like; 32.3% had their diet supplied by a nutritionist. Fibre was the main component taken into account when choosing food (65%) and protein was considered to be the most beneficial nutrient (52%). Attitude: 61.8% of the patients stated that their diagnosis hampered selecting and buying food due to a lack of information. Appetite had not undergone changes in 49.5% of the participants following reflecting on their diagnosis. Practice. 75% of the patients recognised the importance of consuming nutritional supplements and complements; however, only 35.7% of them took them. When buying industrialised/processed food, 66.4% of the patients verified the products' expiry date and/or nutritional data on the label. Conclusions. The food customarily consumed by the patients was that forming part of the average Colombian population's basic weekly food basket; their habits did not significantly differ from those of the rest of the population. Dietary and nutritional information was being obtained from non-professional sources. General practitioners or specialists were referring patients to professional nutritionists; however, self-medication and dosage were common regarding the use and consumption of nutritional complements and supplements. Antecedentes. Los hábitos alimentarios de esta población no ha sido materia de una amplia investigación, incluso concibiendo la importancia que tiene el estado nutricio
¿Son las políticas locales una buena estrategia para dinamizar el mercado de trabajo? Algunos elementos para el caso colombiano
Galvis G.,Diana; López G.,Mauricio;
Perfil de Coyuntura Económica , 2010,
Abstract: in periods of low growth economic, times of recession or crisis economic, implement a fiscal policy counter-cyclical can be a fundamental tool to create jobs and boost the economy. in colombia, specifically in major cities there is a real possibility for local governments, through increases in investment spending, generating a positive impact employment. this article is to review local policies aimed at job creation in a context of economic recession and corroborate the inverse relationship between investment spending and good financial management with respect to the unemployment rate by panel data model with nine cities in the countrybetween theperiod 2001-2009.
Son las políticas locales una buena estrategia para dinamizar el mercado de trabajo? Algunos elementos para el caso colombiano
Diana Galvis G.,Mauricio López G.
Perfil de Coyuntura Económica , 2010,
Abstract: En períodos de bajo crecimiento económico, tiempos de recesión o crisis económica, implementar una política fiscal contra-cíclica puede ser una herramienta fundamental para crear empleo y dinamizar la economía. En Colombia, específicamente en las principales ciudades del país existe una posibilidad concreta para que los gobiernos locales, a través de incrementos del gasto de inversión, impacten positivamente en la generación de empleo. Este artículo tiene por objeto examinar las políticas locales encaminadas a la creación de empleo en un contexto de recesión económica y corroborar la relación inversa entre el gasto en inversión y el buen manejo de las finanzas con respecto a la tasa de desempleo mediante un modelo de datos panel con nueve ciudades del país en el periodo 2001-2009.
Una mirada al álgebra lineal
VIVIAN LIBETH UZURIAGA L.,JHON JAIRO ARIAS M.
Scientia Et Technica , 2006,
Abstract: En este artículo se presentan los resultados del diagnóstico realizado a los estudiantes de ingeniería eléctrica, mecánica, industrial y sistemas y computación de la Universidad Tecnológica de Pereira, sobre las dificultades que ellos tuvieron en el momento de cursar la asignatura álgebra Lineal y las falencias que presentaron cuando trataron de usar las herramientas que ella les aportó para solucionar problemas de otras asignaturas de matemáticas y de ingeniería. Además se presentan conclusiones y recomendaciones acerca del estudio.
Movilización regionalista y nuevos poderes regionales: la fragmentación administrativa del Viejo Caldas y la creación de Risaralda
López Pacheco,Jairo Antonio;
Sociedad y Economía , 2011,
Abstract: this paper looks to an approach to the process of creation of risaralda’s department in 1966 and to the establishment of a new regional power rooted in the formation and performance of a regionalist mobilization. the paper arises the movement’s efficiency as an instance of the existence of a diferenciated social space, in which a new elite with particular features of solidarity, identity and cohesion obtained to dominate the power’s balances and to establish a political and social power legitimated by an identity discourse.
Las organizaciones no gubernamentales de derechos humanos en la democracia. Aproximaciones para el estudio de la politización de los derechos humanos en Colombia
López Pacheco,Jairo Antonio;
Estudios Políticos , 2012,
Abstract: this paper argue that the activity of human rights defense of main ngos in colombia can be analyze as an alternative exercise of social accountability that present relations of control and limit of the abuse of power under the legal and political opportunity structure that supports it. after proposing the problem in the field of representative and participative democracy, their limitations and scope, it establishes a relationship between the type of activities of the ngos and the political effects produced; to demonstrate this relationship builds a typology of forms of activism, the major networks and the various fields of action of human rights ngos in colombia.
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