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Imagen de apoyo de  Self-FEXT Cancellation for use with VDSL2 transceivers: Design, implementation and verification of a tool for numerical performance evaluation

Self-FEXT Cancellation for use with VDSL2 transceivers: Design, implementation and verification of a tool for numerical performance evaluation

Por: Daniel Hincapie Henao | Fecha: 2014

Vectoring is a novel technology created to expand the capacity boundaries of Veryhigh- bit-rate DSL 2 (VDSL2) systems. It mitigates the reduction of data rate and reach in VDSL2 systems caused by the crosstalk interference that appears when multiple services share the telephone network’s infrastructure. However, the implementation of vectoring on real systems faces numerous challenges that limit its potential to enhance the data rate and reach of VDSL2 systems. Therefore, evaluating its performance in close-to-real scenarios considering different technological aspects has turned into an interesting field of research that also helps in the development of new and faster technologies. This thesis evaluates quantitatively the performance of vectoring on VDSL2 systems. It proposes the extension and parametrization of performance indicators to compare and measure the impact of six different aspects on vectoring systems: network topology, binder occupancy, background noise, channel estimation errors, complexity constraints, and precoding and canceling schemes. Their evaluation requires numerical results that are obtained through a simulation tool, which is designed and implemented as part of this thesis. The obtained results and the conducted analyses give concluding guidelines for the vectoring technology and can be taken into account by manufactures and service providers for the deployment of real systems. In addition, and as a result of the objective of providing an accurate evaluation that represents well the real systems’ performance, this thesis contributes with the statistical characterization of the Far-end Crosstalk (FEXT) in a 50-pair cable binder commonly used in Germany (DTAG-40) and constructs its stochastic model. The model and the results are verified through real systems measurements, reference documents of the Broadband Forum and existing literature. Thus, the simulation tool and the characterized channel model constitute a contribution for the evaluation of DSL systems that can be used in future works.
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Self-FEXT Cancellation for use with VDSL2 transceivers: Design, implementation and verification of a tool for numerical performance evaluation

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Imagen de apoyo de  Energy management of a hybrid electric vehicle: an approach based on type-2 fuzzy logic

Energy management of a hybrid electric vehicle: an approach based on type-2 fuzzy logic

Por: Javier Solano Martínez | Fecha: 2012

One of the effects of the globalisation of our society is that people travel more covering longer distances, live far from their work place and consume goods from all around the world. Therefore, it is no coincidence that the transport of people and goods represents more than 25\% of the energy consumption and is one of the principal sources of pollution worldwide. Several efforts must be done to reduce the oil dependence, the energy consumption and the environmental impact of transport systems. In this perspective, the French Army (DGA) has designed and constructed the Electrical Chain Components Evaluation vehicle (ECCE). It is a mobile laboratory to evaluate under real conditions the electric components of Hybrid Electrical Vehicles (HEVs) that reduce the energy consumption and the pollution emission of conventional vehicles. ECCE permits evaluating different energy sources such as batteries, fuel cells, internal combustion engines, ultracapacitors or flywheels. The ECCE project, nowadays in a second phase\footnote{The first phase of the ECCE project is explained in Chapter 1} is developed in joint cooperation with the FEMTO-ST laboratory of the University of Franche-Comté and two industrial partners, HELION and PANHARD General Defense. It aims to study the implementation, control and energy management of different hybrid sources. As a research developed along the second phase of the ECCE project, the principal objective of this thesis is to design, to implement and to evaluate an energy management supervision system in the ECCE HEV. This thesis proposes an original energy management strategy based on expert knowledge and type-2 fuzzy logic. The design of the fuzzy logic controller is done by using knowledge engineering. This technique allows extracting knowledge from several experts using surveys. The consideration of type-2 fuzzy logic systems enables modelling the uncertainty in the answers of the experts. This thesis presents a second application of type-2 fuzzy logic: the voltage regulation of a DC/DC power converter. The principal motivation for developing this application is that it is easier to implement in laboratory at a relatively low cost and it permits a viability evaluation of type-2 fuzzy logic before an implementation in the ECCE mobile laboratory. This is useful because one of the main challenges of this thesis is to reduce the time to experimentally validate the energy management system. This is required to respect the time schedule constraints and to reduce the costs associated to gather the partners of the project at PANHARD locations in Saint-Germain Laval.
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Energy management of a hybrid electric vehicle: an approach based on type-2 fuzzy logic

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Imagen de apoyo de  Organic photodetectors = Fotodetectores organicos

Organic photodetectors = Fotodetectores organicos

Por: Caterin Yojana Salas Redondo | Fecha: 2014

Organic semiconductors are used in many fields of photonics. Displays fabricated using organic light emitting diodes (OLED) can be found in modern smartphones and tablets, whereas organic solar cells (OPV - organic photovoltaics) are emerging with demonstrated efficiencies above 10%. Organic photodetectors (OPD) are another very interesting domain, with ultrathin active layers (order of tens of nanometers) providing performance comparable to bulk inorganic devices. Thanks to a multitude of possible compounds, parameters such as response spectrum, cut-off wavelength etc. can be easily tuned. Because of very high absorption coefficient and low refractive index, issues such as crosstalk or reflection can be minimized. Another exciting feature is the low processing temperature and thus feasibility of using a flexible foil as substrate, leading to rollable or curved photodetector arrays.The performance of organic based photodetectors has grown considerably in the recent years in terms of high speed, high frequency response and detectivity so as to match the required custom specifications for practical applications such as imaging. However, further attention needs to go towards the understanding of the effects of scaling during miniaturization of these devices, while looking for the preservation and/or optimization of their opto-electrical properties. Therefore, in this thesis, emphasis is given on the photodetectors based on organic conjugated polymer materials for imaging applications. These organic photodetector devices normally suffer from a perimeter-to-area dark current density scaling, hence, special attention is on the understanding of this scaling effect as well as optimization of the fabrication process in order to get low leakage (dark) current, and therefore, large dynamic range of the OPDs. Photodetectors with different geometries and sizes from 0.08 cm2 down to 1.95E ?5 cm2 were fabricated, using two types of edge cover layer. Isolated islands of two different organic films were patterned with photolithography in order to study the dark current mechanisms. Electrical, optical and morphological properties were characterized for both patterned and non-patterned devices. The patterning process used to fabricate the isolated devices does not affect the optoelectrical and morphological characteristics of the photodetectors, and therefore their performance. Moreover, it does not induce or accelerate degradation of the organic films. The dark current density further decreases after full patterning is performed, while preserving all device characteristics. It is proposed to replace the semitransparent edge cover layer by the opaque, if thicker films can be achieved, as it might be possible to decrease the contribution of the perimeter leakage. Once the patterning process is performed, it is possible to implement these isolated devices as photodetectors arrays for imaging applications with an Ion/Ioff ratio of 6 orders of magnitude. It is proposed to perform a theoretical study of the dark current mechanism at the interface between the polymer and the metallic contact edges to model and simulate the perimeter recombination at reverse bias conditions. Moreover, further measurements such as electroluminescent and spectroscopy might aid to characterize the carrier transport in the OPDs. The project was aimed within the R&D department of large area electronics. Moreover, all the fabrication and characterization were performed in the facilities of IMEC.
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Organic photodetectors = Fotodetectores organicos

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Imagen de apoyo de  A Framework For The Managemente Of The Biodegradable Waste In Bogotá-Colombia = Un Marco Para El Manejo De La Basura Biodegradable En Bogotá-Colombia

A Framework For The Managemente Of The Biodegradable Waste In Bogotá-Colombia = Un Marco Para El Manejo De La Basura Biodegradable En Bogotá-Colombia

Por: Adriana Lizette Gutiérrez Bayona | Fecha: 2014

Waste management is one of the growing problems in many highly populated cities around the world, and the amount of strategies designed to solve it has changed during the last decade. It passed from land filing to incineration and mechanical biotechnology; this quick change was partially induced by the threat that garbage is for the environment, and later on by the acceleration of climate change, since the public services industry was bound to comply with the emissions reduction targets. The newest technologies are being applied in Europe and North America, giving them a new way to face their waste issues. However, the industrialized States are not the only ones with these concerns, in the developing countries, it is a matter that is becoming an structural problem, because of the population growth and the dynamics of the capitalist practice; moreover, it is difficult to solve due to low budget or lack of knowledge on the topic. In Bogotá D.C, waste management became one of the most controversial topics due to the many problems presented during the implementation of the Zero-Waste program and the past administrative issues with the Landfill Doña Juana that led to many health and land predicaments for the population. As a consequence, this dissertation seeks to create a new strategy to fix the gaps of the original policy, by designing five time-limited specific objectives, a reform to the segregation strategy and proposing the construction Anaerobic Digestion plant as the best solution for the sustainable control of bio-waste. Therefore, this work will show throughout all the chapters the background of the waste management system, the new strategies to be taken into account by the local administration, the advantages of the AD technology and the possible financing channels for the renovation of the Basuras- Cero Policy. All the information above will be use to conclude, that for the case of Bogotá D.C, the use of bio-waste as a new energy source will strengthen the recycling industry (with the establishment of a better segregation system and the construction of and AD plant) reduce the amount of waste sent to Landfill and decrease GHG emissions; and even though it is a small step, it can become the foundation for fixing some weaknesses of the economic system and some social mores.
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A Framework For The Managemente Of The Biodegradable Waste In Bogotá-Colombia = Un Marco Para El Manejo De La Basura Biodegradable En Bogotá-Colombia

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Imagen de apoyo de  Sensing with a 3-toe foot for a mini biped robot = Midiendo con un pie de 3 dedos para mini robots bipedos

Sensing with a 3-toe foot for a mini biped robot = Midiendo con un pie de 3 dedos para mini robots bipedos

Por: Sergio Orlando Castro Gómez | Fecha: 2014

El trabajo presenta el diseño e implementación de un pie de tres dedos para robots bípedos. El sistema es capaz de medir el centro de presión sobre superficies planas e irregulares. El modelo ha sido creado para ser usado en robots bípedos, suministrando información sobre el centro de presión y el punto de momento cero. Dicha información es usada como entrada para un sistema de control, que asegurará la estabilidad del robot durante su caminata por diferentes superficies.
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Sensing with a 3-toe foot for a mini biped robot = Midiendo con un pie de 3 dedos para mini robots bipedos

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Imagen de apoyo de  The underestimated value of safety in achieving organizational goals: cast analysis of the macondo accident = El subestimado valor de la seguridad industrial en el logro de objetivos organizacionales: Análisis CAST del Accidente de Macondo

The underestimated value of safety in achieving organizational goals: cast analysis of the macondo accident = El subestimado valor de la seguridad industrial en el logro de objetivos organizacionales: Análisis CAST del Accidente de Macondo

Por: María Fernanda Tafur Muñoz | Fecha: 2017

Abstract: On April 20, 2010, an explosion in the rig Deepwater Horizon performing drilling operations on the Macondo Prospect Well, in the Gulf of Mexico, led to the largest oil spill in the history of the petroleum industry. Eleven crewmembers lost their lives and around 4.9 million barrels of oil were discharged into the ocean until the continuous subsea blowout of the well was contained in September 19, 2010. Given the magnitude and the complexity of the accident, several safety analyses have been proposed by the international community at different levels of the system involved in the accident. Most of these studies use accident analysis techniques based on chain-of-event models, whose main objective is to identify root-causes. However, while this approach describes physical phenomena accurately, it does not explain the role of organizational and socio-economical factors, human decisions, or design inaccuracies in accidents in complex, adaptive, and tightly coupled systems like Macondo. In response to this need, N. Leveson developed the new accident-analysis technique Causal Analysis Based on System Theory (CAST), based on her model System-Theoretic Accident Model and Processes (STAMP). In STAMP accidents are not treated as chain of failure events, but as complex processes that result from a large variety of causes including component failures and faults, system design errors, unintended and unplanned interactions among system components, human operator errors, flawed management decision-making, inadequate controls and oversight, and poor safety culture. This thesis presents management recommendations based on a CAST analysis of the Macondo Accident. The goal is to help the oil and gas offshore drilling community achieve safer operations and understand the value of systems safety in achieving organizational goals. Resumen: El 20 de abril de 2010, una explosión en la plataforma Deepwater Horizon, la cual estaba ejecutando operaciones de perforación en el pozo exploratorio Macondo, en el Golfo de Méjico, resultó en el mayor derrame de crudo de la historia de la industria petrolera. Once trabajadores perdieron su vida y cerca de 4,9 millones de barriles de crudo contaminaron el océano hasta que el escape fue contenido el 19 de septiembre de 2010. Dada la magnitud y complejidad del accidente, múltiples análisis de seguridad industrial han sido propuestos por la comunidad internacional examinando diferentes niveles del sistema organizacional involucrado en el accidente. La mayoría de estos estudios usan técnicas de análisis basadas en modelos de cadena de eventos, cuyo objetivo principal es identificar causa raíces. Sin embargo, mientras este enfoque describe procesos físicos acertadamente, no explica el papel de factores organizacionales y socio-económicos, decisiones humanas, o imprecisiones de diseño en accidentes sucedidos en sistemas organizacionales complejos, adaptativos, y estrechamente acoplados como el de Macondo. En respuesta a esta necesidad, N. Leveson desarrolló la nueva técnica de análisis de accidentes Análisis Causal Basado en la Teoría de Sistemas (CAST por sus siglas en inglés), basada en su Modelo y Proceso Teórico de Análisis de Sistemas (STAMP por sus siglas en inglés). En STAMP, los accidentes no se tratan como eventos de cadena de fallas, sino como procesos complejos que resultan de una gran variedad de causas, incluidas defectos y fallas de componentes, errores de diseño del sistema, interacciones involuntarias e inesperadas entre los componentes del sistema, errores de operadores humanos, decisiones gerenciales equivocadas, controles y supervisiones inadecuados, y deficiencias en la cultura de seguridad industrial. Esta tesis presenta recomendaciones de gestión basadas en un análisis CAST del accidente de Macondo. El objetivo es ayudar a la comunidad de perforación petrolera a lograr operaciones más seguras y comprender el valor de la seguridad industrial en el logro de objetivos organizacionale.
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The underestimated value of safety in achieving organizational goals: cast analysis of the macondo accident = El subestimado valor de la seguridad industrial en el logro de objetivos organizacionales: Análisis CAST del Accidente de Macondo

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Imagen de apoyo de  Evaluating the economic feasibility of biochar production as a means of carbon capture and storage = Evaluación de factibilidad de la producción de biochar como método de captura y almacenamiento de dióxido de carbono

Evaluating the economic feasibility of biochar production as a means of carbon capture and storage = Evaluación de factibilidad de la producción de biochar como método de captura y almacenamiento de dióxido de carbono

Por: David Echeverry Gómez | Fecha: 2014

Carbon Capture and Storage (CCS) is an emerging technology designed to tackle climate change by making processes more sustainable. This work gives a technical review of the current status of this process in order to compare it with the production of biochar. The latter is a carbon-rich material obtained when biomass is heated in the absence of oxygen. Although this production technique, which is called pyrolysis, has been known for centuries, there is little information regarding its process at an industrial level. As a result, this dissertation presents a study of the feasibility of biochar production as a means of carbon capture and storage. In other words, this research generates an approach to provide a preliminary estimate of the potential of large-scale biochar production to reduce atmospheric CO2. In this context, it is important to consider that pyrolysis-based biochar could be valuable in terms of soil improvement, crop yield increase, bioenergy generation and greenhouse gas (GHG) offsets. In this perspective, there are two categories of pyrolysis: fast and slow. Fast pyrolysis produces biochar in a matter of seconds, whereas slow pyrolysis produces a higher conversion to biochar but in a matter of hours. Generally speaking, the pyrolysis-based process is considered to be carbon-negative, because biochar production could reduce the amount of carbon in the atmosphere. In terms of the data analysis, several factors were considered and some assumptions were made. These assumptions are based on the literature because biochar production is not yet available at a commercial scale. According to the results, the cost to capture a tonne of carbon dioxide is $6.47 and $32.49 for fast and slow pyrolysis respectively. Therefore, although it is not a profitable technology, it could be cost competitive compared with CCS projects.
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Evaluating the economic feasibility of biochar production as a means of carbon capture and storage = Evaluación de factibilidad de la producción de biochar como método de captura y almacenamiento de dióxido de carbono

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Imagen de apoyo de  Suction and volume changes of Compacted sand-bentonite mixtures = Cambios volumétricos y de succión en muestras compactadas de arena-bentonita

Suction and volume changes of Compacted sand-bentonite mixtures = Cambios volumétricos y de succión en muestras compactadas de arena-bentonita

Por: Julio Esteban Colmenares Montañez | Fecha: 2002

Engineered barriers are used in the containment of hazardous materials and are usually a composite of compacted clayey soil and a synthetic membrane. Containment elements such as landfill liners should be designed to control or prevent leachate migration or groundwater ingress. Engineering specifications for a compacted clay liner are based mainly in a hydraulic conductivity less than 10-9 m/s and the need for stability during construction and operation of the landfill. Sandbentonite mixtures are often used as a barrier material. The addition of relatively small amounts of bentonite (5-15%) can improve the performance of a granular material providing both a low permeability and an enhanced mechanical stability. However not all the possible compaction conditions produce a low permeability and mechanically stable material. Changes in water content after compaction can cause swelling or collapse depending on the stress and suction conditions before the water content change occurs. A laboratory investigation of the swelling-collapse behaviour of compacted mixtures of Sand-bentonite has been undertaken. Compaction and suction characteristics were established. The suction and volume change characteristics were investigated through a series of oedometer tests. The central part of the experimental programme focused on the detailed investigation of the processes of swelling and collapse during controlled wetting.To do this, a significant number of modifications were required to the existing apparatus. Fabric studies including Environmental Scanning Electron Microscopy and Mercury Intrusion Porosimetry were also undertaken. Intrinsic behaviour and the relationship between suction and water content were comprehensively studied. A parametric study of the influence of bentonite content and sand grading was also undertaken. The results are presented and analysed. Recommendations for future research are made.
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Suction and volume changes of Compacted sand-bentonite mixtures = Cambios volumétricos y de succión en muestras compactadas de arena-bentonita

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Imagen de apoyo de  Operational guideline for composting projects in developing countries = Guía operativa para proyectos de compostaje en países en desarrollo

Operational guideline for composting projects in developing countries = Guía operativa para proyectos de compostaje en países en desarrollo

Por: Natalia Giraldo Gómez | Fecha: 2014

During the last decades there has been an increase in the generation of solid wastes in the world, in developing countries the situation has been specifically critical since in many cases there is no adequate treatment for the solid waste due to the scarcity of the resources and to the poor conscience of the real situation and possible consequences. This document presents the composting method as a suitable alternative for the treatment of solid waste in developing countries considering that its costs are not so high and that the composition of the solid waste is mainly organic. The analysis was based on a current literature review and on the study of some cases of composting projects, according to the results an operational guideline for the development of composting projects in developing countries was proposed. The guideline is composed of two main cores: the planning system and the evaluation system. The planning system supports the development of a composting project and the evaluation system is a base for the comparison of performance between different future cases.
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Operational guideline for composting projects in developing countries = Guía operativa para proyectos de compostaje en países en desarrollo

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Imagen de apoyo de  QoS Performance Evaluation of a Real‐Time Mobile Video Surveillance in a LTE Network = Evaluación de Rendimiento de QoS de un Sistema de Video Vigilancia en una red LTE

QoS Performance Evaluation of a Real‐Time Mobile Video Surveillance in a LTE Network = Evaluación de Rendimiento de QoS de un Sistema de Video Vigilancia en una red LTE

Por: Sebastián Pineda Carrillo | Fecha: 2013

Long Term Evolution (LTE) is one of the latest mobile communication technologies being commercially deployed worldwide. It has emerged as a promising technology for new applications such as mobile video surveillance (IPVS) due to its higher data throughputs as well as the quality of the service management capabilities. This work focuses on the performance evaluation of a mobile and real-time IPVS system over a LTE network in both operation modes, namely FDD and TDD. The QoS Requirements for the IPVS were defined and two simulation analyses were performed in OPNET Modeler in order to compare them to the QoS Delivered. The first analysis studied the performance of the IPVS service from a capacity point of view in a single cell scenario while the second analysis looked at the performance of the IPVS service in a sample network configuration including several cells. In light of the analysed results it was evidenced the flexibility of TDD operation mode in terms of capacity as well as its higher delay and packet delay behaviours in comparison with FDD operation mode. Additionally it was shown that TDD index 6 does not comply with the QoS performance required for an IPVS service in a multi cell network. 
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QoS Performance Evaluation of a Real‐Time Mobile Video Surveillance in a LTE Network = Evaluación de Rendimiento de QoS de un Sistema de Video Vigilancia en una red LTE

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