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Cajón Digital para jóvenes y adultos.

Selección de libros, enfocada a jóvenes y adultos, para complementar la colección del PPP Tibabuyes. Encontrarás textos de diferentes géneros: novela, cuento, poesía, informativo e instructivos.

Contenidos de esta colección

Imagen de apoyo de  La mansión de Araucaíma y otros relatos

La mansión de Araucaíma y otros relatos

Por: Alvaro Mutis | Fecha: 01/01/1996

The main challenge of this Thesis is to reliably preserve quality of service (QoS) contracts in component-based software systems under changing conditions of system execution. In response to this challenge, the presented contribution is twofold. The first is a model for component-based software applications, QoS contracts and reconfiguration rules as typed attributed graphs, and the definition of QoS-contracts semantics as state machines in which transitions are performed as software reconfigurations. Thus, we effectively use (formal) models at runtime to reliably reconfigure software applications for preserving its QoS contracts. More specifically, we show the feasibility of exploiting design patterns at runtime in reconfiguration loops to fulfill expected QoS levels associated to specific context conditions. We realize this formal model through a component-based architecture and implementation that can be used as an additional layer of SCA middleware stacks to preserve the QoS contracts of executed applications. The second contribution is the characterization of adaptation properties to evaluate self-adaptive software systems in a standardized and comparable way. By its own nature, the adaptation mechanisms of self-adaptive software systems are essentially feedback loops as defined in control theory. Thus, it results reasonable to evaluate them using the standard properties used to evaluate feedback loops, re-interpreting these properties for the software domain. We define the relibility of our formal model realization in terms of a subset of the characterized adaptation properties, and we show that these properties are guaranteed in this realization.
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QoS-CARE: A Reliable System for Preserving QoS Contracts through Dynamic Reconfiguration = QoS-CARE: Un Sistema Confiable para Preservar Contratos de QoS a través de Reconfiguración Dinámica

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Imagen de apoyo de  La isla del tesoro

La isla del tesoro

Por: Robert Louis Stevenson | Fecha: 01/01/2008

La regularidad de intervalos entre buses ha demostrado mejorar el nivel de servicio de sistemas de transporte público, reduciendo tiempos de espera de pasajeros, balanceando la carga de los buses y logrando ahorros en costos operacionales. Este trabajo evalúa el modelo de optimización desarrollado por Delgado et al. (2012), que controla los intervalos entre buses, a través de su implementación en EMBARQ BRT Simulator, usando datos reales y teniendo en cuenta consideraciones prácticas de implementación.Se adaptó EMBARQ BRT Silmulator para incluir las estrategias de control en la simulación y permitir su interacción con el modelo de optimización que fue modificado para permitir la solución de problemas de gran tamaño. Para estudiar los beneficios de las estrategias de control se usan datos reales de la única línea que opera en el corredor BRT Insurgentes de Ciudad de México D.F.Se definen y evalúan escenarios donde se establecen los beneficios de implementar diferentes esquemas de control en el corredor. Los parámetros estudiados incluyen: (i) intervalo de tiempo entre optimizaciones; (ii) número de paraderos incluidos en la optimización; y (iii) combinación de acciones de control como retención (holding), delimitación de pasajeros a abordar el bus (boarding limits) y la posibilidad de no permitir subidas en determinadas paradas.Para el caso de estudio, la estrategia de sólo holding, optimizando cada 2 minutos y considerando 12 de los 72 paraderos, redujo en 21% los tiempos de espera total percibidos, la variabilidad en 39% y mostró ahorros para el operador del 5% de la flota. Las estrategias que consideran limitaciones prácticas, mostraron beneficios similares a los casos sin ellas, demostrando su factibilidad de implementación en casos reales. Finalmente, se recomienda implementar el modelo en un corredor real, donde se podría usar EMBARQ BRT Simulator para la evaluación de estrategias de control.
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Implementación de modelo para control de intervalos a buses en un corredor de pistas segregadas en EMBARQ BRT Simulator

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Imagen de apoyo de  Historias extraordinarias

Historias extraordinarias

Por: Edgar Allan Poe | Fecha: 01/01/2015

Usually, an actuary would begin by trying to study a particular consumer insurance pool. In this work, I am working on Colombia and soon, I struggled in having complete and precise information. Indeed, it is a recurrent issue for actuaries studying most emerging countries. The next step would be to estimate the risks an insurance company will have to face in order to create profitable products. I was interested in studying Climatic risks and, since Colombia's weather is interesting. I decided to study the floods in Colombia. Colombian weather is ruled by still unpredictable and random events: El Niño and La Niña that bring droughts and floods. Once again, I quite struggled in having reliable insurance information about the floods since this risk has never been surveyed separately from the overall house damages before 2010. From 2010 to 2012, because of the frequency and the importance of the floods, insurance companies have been trying to study the cost of climatic catastrophes but it was not profitable enough for them to keep on. Indeed, there are not enough people subscribing to house insurances for it to be profitable. Hence, I did not work only on 2010-2012 data because it does not allow me to stand back enough. I worked with the overall house damages data. Finally, from the two previous analysis, an actuary have to adapt his product to the consumer market.
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Flooding in Colombia : attempt to model it and answer it with adapted products = Inundaciones en Colombia: como modelarlas con productos adecuados

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Imagen de apoyo de  Historia de un amor turbio

Historia de un amor turbio

Por: Jairo Andrés González Pérez | Fecha: 01/01/2008

This thesis investigates the turbine performance of a particular tidal energy conversion device analysing the hydrodynamic variables based on computational fluid dynamics simulations. Renewable tidal energy technology is undergoing a rapid development due to its advantages and new and creative designs of marine current turbines which are constantly being studied and improved. As a result, incorporating diffusers to accelerate the flow is a method used to increase the efficiency of the turbines. However, this practice has to be evaluated and parameterised to ensure its viability. Therefore, an experimental test of a ducted turbine, carried out in 2010, was selected for analysis with the aim of improving diffuser efficiency without studying the diffuser design but other variables in the system.The advantage of this strategy applied to a particular case is that the knowledge achieved can be used to benefit any diffuser design on many tidal turbines. The diffuser that was used in the 2010 experiment exhibited a low increment in power extracted and the main objective of this thesis arises from the question of how it could be possible to extract much more power using such ducted turbine with the same rotor and diffuser because the interaction of device components and characteristics of water flow causes an impact on the flow field, and therefore in extraction of energy. A methodology based on two hypotheses was developed to understand the influence of diffuser over the flow. The hypotheses addressed two areas: effects produced by a strut characteristic of turbine design and influence of the free surface.
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Hydrodynamic CFD study of a ducted turbine = Estudio hidrodinámico de una turbina canalizada

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