Saltar navegación e ir al contenido principal
Biblioteca digital de Bogotá
Logo BibloRed
Cargando contenido
¿Qué estás buscando?
  • Escribe palabras clave como el título de un contenido, un autor o un tema que te interese.

  • Búsqueda avanzada

Seleccionar

Contenidos y Experiencias Digitales

Filtrar

Formatos de Contenido
Tipo de colección
Género
Idioma
Derechos de uso

Selecciona contenidos según las condiciones legales para su uso y distribución.

Estás filtrando por

Cargando contenido

Se encontraron 409 resultados en recursos

Imagen de apoyo de  Towards Training Person Detectors for Mobile Robots using Synthetically Generated RGB-D Data = Entrenamiento de detectores de personas para robótica móvil usando conjuntos de datos RGB-D generados sintéticamente

Towards Training Person Detectors for Mobile Robots using Synthetically Generated RGB-D Data = Entrenamiento de detectores de personas para robótica móvil usando conjuntos de datos RGB-D generados sintéticamente

Por: Timm; Hernández León Linder | Fecha: 2019

We explore how we can use synthetically generated RGB-D training data from a near photo-realistic game engine to train modality-specific person detectors. We perform ablation studies on a challenging, real-world dataset which we recorded using a Kinect v2 RGB-D sensor in multiple warehouse environments. Through extensive use of domain randomization techniques, we synthesize a realistic and highly varied training set of challenging intralogistics scenarios as observed from a mobile robot, comprising persons in confined and cluttered indoor spaces. We then train the detector layers of a YOLOv3 model from scratch on our synthetic RGB and jet-encoded depth images. While for the RGB case, we still observe a domain gap of 6 points in mAP compared to a pretrained COCO model, results indicate that by exploiting simulation, an immense manual labeling effort needed to prepare large-scale datasets such as MS COCO might be unnecessary for the depth modality. We further find that filtering of highly occluded groundtruth boundin boxes during training, as well as modeling of time-of-flight sensor noise characteristics has a positive impact on model performance. We also provide an initial set of qualitative results on our real-world dataset.
Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Artículos
  • Temas:
  • Otros
  • Ingeniería

Compartir este contenido

Towards Training Person Detectors for Mobile Robots using Synthetically Generated RGB-D Data = Entrenamiento de detectores de personas para robótica móvil usando conjuntos de datos RGB-D generados sintéticamente

Copia el enlace o compártelo en redes sociales

Imagen de apoyo de  Synthetic data generation using game engines for deep learning in robotics = Generación de conjuntos de datos sintéticos usando motores de juego para aplicaciones de deep learning en la robótica

Synthetic data generation using game engines for deep learning in robotics = Generación de conjuntos de datos sintéticos usando motores de juego para aplicaciones de deep learning en la robótica

Por: Michael Johan Hernández León | Fecha: 2019

An accurate understanding of the environment is key for a robot in order to execute tasks safe and efficiently. In the field of perception, after the introduction of deep learning, computer vision tasks have made big leaps, surpassing even the human inference capability. As a trade-off, big amounts of annotated data were required to train such algorithms. On its own, the collection of annotated dataset is a highly time consuming activity prone to human errors, setting a limit to the maximum achievable performance. In this sense, annotations (quality) and samples (quantity) bound the optimization of perception algorithms. One extra challenge encountered when training object detectors for robotics applications is that the sensor setup can be multi-modal, and vary significantly between robots. This work explores how to generate and use synthetic RGB-D training data from a near photo-realistic game engine to train modality-specific person detectors, and perform ablation studies on a challenging, real-world dataset recorded using a reference RGB-D sensor in different intralogistics environments. A virtual RGB-D camera was implemented, leveraging the underlying deferred rendering architecture. Multiple environments were tailored, exploring various data augmentation techniques and enabling the comparison between different types of synthetic data. Detection layers of a pre-trained object detector network have been trained from scratch for the RGB and depth modality, with the latter being transformed by applying a Jet-colormap. Compared to a pre-trained network, a domain gap of 5 mPA points was still present for RGB images. Meanwhile with synthetic (15k) and real (1.5k) depth images, it was already possible to train robust human detectors. Comparing simulation features against data preparation, filtering annotations had a major impact on performance than adopting an explicit time-of-flight sensor model.
Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Tesis
  • Temas:
  • Otros
  • Ingeniería

Compartir este contenido

Synthetic data generation using game engines for deep learning in robotics = Generación de conjuntos de datos sintéticos usando motores de juego para aplicaciones de deep learning en la robótica

Copia el enlace o compártelo en redes sociales

Imagen de apoyo de  Probing Photon Emission in Quantum Dots coupled to a Superconducting Resonator = Detectando la emisión de fotones en puntos cuánticos acoplados a un resonador superconductor

Probing Photon Emission in Quantum Dots coupled to a Superconducting Resonator = Detectando la emisión de fotones en puntos cuánticos acoplados a un resonador superconductor

Por: Kristian Samuel Cujia Peña | Fecha: 2014

Within the last decade circuit quantum electrodynamics (circuit QED) [1] has proven to be an excellent platform to study the coherent interaction between an artificial atom and a light field. Here an artificial atom, or more precisely an effective two level system, is realized using superconducting circuitry while the cavity is realized as a microwave resonator. Recently, an effective two level system realized using a semiconductor double quantum dot (DQD) has been coupled to a microwave resonator. In this hybrid system, interactions between the dipole moment of (single) electrons in a DQD and the electromagnetic field in a microwave resonator have been observed (2,3). Using the same architecture, we initially discuss experiments performed with a resonator sample in order to investigate design parameters influencing its quality factor. With the aim of enabling high bandwidth correlation measurements, we then present the design and implementation of parallel digital filters in a digital signal processing platform. We finally report on experiments to use the microwave resonator as a tool to explore fundamental processes occurring in a DQD driven out-of-equilibrium. In particular, we perform exploratory attempts to probe the microwave radiation emitted from a voltage-biased DQD by means of first and second order correlation function measurements. Resumen: En la última década, la electrodinámica cuántica de circuitos (circuit QED) [1] ha demostrado ser una excelente plataforma para estudiar la interacción coherente entre un átomo artificial y un campo de luz. El esquema consiste en un átomo artificial, o más precisamente un sistema efectivo de dos niveles, implementado usando circuitos superconductors, mientras que la cavidad se implementa como un resonador de microondas. Recientemente, se ha acoplado un sistema de dos niveles, implementado utilizando un punto cuántico doble de semiconductores (DQD), a un resonador de microondas. En este sistema híbrido, se han observado interacciones entre el momento dipolar de electrones (individuales) en un DQD y el campo electromagnético en un resonador de microondas [2,3]. Utilizando la misma arquitectura, inicialmente discutimos experimentos realizados con un resonador para investigar los parámetros de diseño que influyen en su factor de calidad. Con el objetivo de permitir mediciones de correlación de alto ancho de banda, presentamos el diseño e implementación de filtros digitales paralelos en una plataforma de procesamiento digital de señales. Finalmente, presentamos experimentos para utilizar el resonador de microondas como herramienta para explorar los procesos fundamentales que ocurren en un DQD operado fuera de equilibrio. En particular, realizamos intentos exploratorios para sondear la radiación de microondas emitida por un DQD (polarizado con una diferencia de voltage) por medio de mediciones de la función de correlación de primer y segundo orden.
Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Tesis
  • Temas:
  • Otros
  • Ingeniería

Compartir este contenido

Probing Photon Emission in Quantum Dots coupled to a Superconducting Resonator = Detectando la emisión de fotones en puntos cuánticos acoplados a un resonador superconductor

Copia el enlace o compártelo en redes sociales

Imagen de apoyo de  Analysis of the operational flexibility of the Italian power system in 2030 = Análisis de la flexibilidad operacional del sistema eléctrico italiano en el 2030

Analysis of the operational flexibility of the Italian power system in 2030 = Análisis de la flexibilidad operacional del sistema eléctrico italiano en el 2030

Por: Juan David Correa Laguna | Fecha: 2019

In 2019, the European Commission published the “2030 Clean Energy for All Europeans” package, as part of the 2050 Energy roadmap. To comply with the European directives, Italy published the National Energy and Climate Plan setting a target of 55% for RES share in electricity generation by 2030. This high RES generation target raises concerns about the operational flexibility of the Italian power system. The flexibility of the Italian power system was measured using currently available flexibility frameworks and indexes (e.g.: AFPER, FAST2). Hence, the 2030 Base Scenario and 15 alternative scenarios were simulated using Promed Grid, a market tool developed by CESI and able to perform a coordinated hydro- thermal dispatching over a one-year horizon, considering the adoption of some flexibility sources such as storage systems and demand response. The results were then compared to characterize the performance of each flexibility source and its influence on the power system. BESS, PHS, and DR showed a level of complementarity while covering flexibility needs and controlling price spikes. Daily needs are covered mainly by BESS and weekly needs by PHS, mainly during the summer since both technologies were more used due to high solar power generation. Conversely, peak shedding DR was primarily activated in winter since prices are higher and storage systems lees used. In the case of V2G and DR, the role of aggregators is vital to have a representative capacity to be offered in the power markets. Finally, from a holistic perspective, the benefits of implanting all flexibility source are higher than the costs. Nevertheless, such benefits should be redistributed to incentivize the deployment of certain sources with low benefit-cost ratios. The results of this thesis can serve as a starting point to delve into the technical performance and economic implications of each flexibility source. In addition, it highlighted the advantages for Italy of boosting and supporting some schemes such as DR and V2G, as well as incentivizing the installation of storage systems.
Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Tesis
  • Temas:
  • Otros
  • Ingeniería

Compartir este contenido

Analysis of the operational flexibility of the Italian power system in 2030 = Análisis de la flexibilidad operacional del sistema eléctrico italiano en el 2030

Copia el enlace o compártelo en redes sociales

Imagen de apoyo de  Problemas de inestabilidad global en tableros metálicos y mixtos de puentes atirantados

Problemas de inestabilidad global en tableros metálicos y mixtos de puentes atirantados

Por: Juliana Palacio Gómez | Fecha: 2022

Resumen: Los puentes atirantados son una tipología muy eficiente que posee agradables atributos estéticos. En los últimos años ha emergido como el sistema dominante para puentes de grandes luces, hasta 1200 m gracias a la combinación de distintos avances tecnológicos que la han convertido en muy competitiva. Aparte de la estabilidad aerodinámica, para esta tipología es relevante el estudio de la estabilidad del equilibrio elástico global y local del tablero frente a las cargas de compresión que se generan por el esquema de atirantamiento. En este trabajo se presenta un estudio paramétrico en puentes atirantados que permite identificar y evaluar un rango de luces donde los fenómenos de inestabilidad global del tablero son significativos. Para lograr este análisis se plantean varios objetivos, inicialmente de estudio, luego de modelación e identificación de rangos y finalmente de análisis y conclusiones. Los temas estudiados para el estado del conocimiento son la evolución del proyecto de tableros de puentes atirantados metálicos y mixtos en función de la luz, así como la tipología de tableros en función de la luz del tablero frente a los fenómenos de inestabilidad global. Para la modelización del tablero se considera el modelo de viga sobre cimentación elástica o modelo de Winkler con módulo de reacción constante y variable, junto con esfuerzos axiles de variación constante y variable. Con los resultados obtenidos se identifican rangos de luces donde la inestabilidad es importante para el análisis, al cual se le evalúan sus efectos no lineales y su posible repercusión en el proyecto del tablero.
Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Tesis
  • Temas:
  • Otros
  • Ingeniería

Compartir este contenido

Problemas de inestabilidad global en tableros metálicos y mixtos de puentes atirantados

Copia el enlace o compártelo en redes sociales

Imagen de apoyo de  Modification, Implementation and Validation of IEC 61400-1, v.4 to Determine the Probability of Extreme Winds Induced by Cyclones in the Northwest Pacific

Modification, Implementation and Validation of IEC 61400-1, v.4 to Determine the Probability of Extreme Winds Induced by Cyclones in the Northwest Pacific

Por: Iván Camilo; Jenssen Viveros Góngora | Fecha: 2021

Abstract: The standard IEC 61400-1, v.4.0 proposes at appendix J a method to determine the probability of extreme winds, based on the simulation of artificial cyclones and the theory of gradient wind. This method considers marginal statistical distributions for 5 main descriptors of cyclones (pressure depth, radius of maximum wind speed, translation speed, angle to the point of reference and mini-mum distance), a “modified orthogonal decomposition” to generate artificial cyclones and its own formulas to determine surface wind, cumulative probabilities and annual maximum surface wind. This research pursued to implement and to validate the standard at North West Pacific. Due to the difficulty and highly empirical elements of IEC 61400-1, v.4.0, it was required to modify it and include in the model other inputs such as well known statistical distributions after testing them, Nataf trans-formation (ERANataf) to generate artificial cyclones and empirical cumulative distribution functions to determine the probability of annual maximum surface wind. For the verification and validation, the results of 9 locations distributed in South Korea, Japan, HongKong and Taiwan were compared with the database of the Joint Typhoon Warning Center and theRSMC-Tokyo. The implementation of this research underestimated surface wind in all the locations.Simultaneously, the greatest contribution of input variables to sensitivity was more frequent from super index B of Holland. It would be desirable to continue validating this standard (that is presumed to have a global application), to understand the challenges of its theory during the computation of surface wind from gradient wind and to overcome the issues of its implementation.
Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Tesis
  • Temas:
  • Otros
  • Ingeniería

Compartir este contenido

Modification, Implementation and Validation of IEC 61400-1, v.4 to Determine the Probability of Extreme Winds Induced by Cyclones in the Northwest Pacific

Copia el enlace o compártelo en redes sociales

Imagen de apoyo de  Damping TENS-Induced Essential Tremor Symptoms in Activities of Daily Living Using the TuMove Wrist Exoskeleton

Damping TENS-Induced Essential Tremor Symptoms in Activities of Daily Living Using the TuMove Wrist Exoskeleton

Por: Jose Arturo; Paredes Acuña Garcia Higuera | Fecha: 2023

Abstract: Essential Tremor (ET) is the most frequent movement disorder in adults. Upper-limb exoskeletons are a promising solution to alleviate ET symptoms. We propose a novel wrist exoskeleton for tremor damping. The TuMove exoskeleton is light-weight, portable, easy to use, and designed for ADLs and activities requiring hand dexterity. We validated the effectiveness of our exoskeleton by inducing forearm tremors using TENS on 5 healthy subjects. Our results show that wrist ranges are generally kept in most of the ROM needed in ADLs. The damping system reduced more than 30% of the tremor's angular velocity during drinking and pouring tasks. Furthermore, the completion time of the Archimedes spiral was decreased by 2.76 seconds (13.0%) and for the 9-Hole-Peg-Test by 2.77 seconds (11.8 %), indicating a performance improvement in dexterity tasks.
Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Artículos
  • Temas:
  • Otros
  • Ingeniería

Compartir este contenido

Damping TENS-Induced Essential Tremor Symptoms in Activities of Daily Living Using the TuMove Wrist Exoskeleton

Copia el enlace o compártelo en redes sociales

Imagen de apoyo de  Experimental and numerical analysis of preload in Extended Hollo-Bolt blind bolts = Análisis experimental y numérico de pretensión en Extended Hollo-Bolts

Experimental and numerical analysis of preload in Extended Hollo-Bolt blind bolts = Análisis experimental y numérico de pretensión en Extended Hollo-Bolts

Por: Manuela; Tizani Cabrera Durán | Fecha: 2021

Abstract: Adequate initial bolt preload is necessary to ensure the strength and stiffness of bolted connections. In this study, an experimental torque control method was used to determine the relationship between tightening torque and preload of nine Extended Hollo-Bolt (EHB) blind bolted connections to Concrete-Filled Steel Hollow Sections (CFSHS). In order to obtain the EHB nut factors, which allow to calculate the level of preload for any value of applied torque, torque versus preload curves were drawn based on the experimental results and curve fitting method was carried out. Bolt preload relaxation was also recorded for a period of 7 days while concrete hardening occurred. Additionally, a detailed 3D Finite Element (FE) model of the tightening stage of the EHB was established. The experimental and numerical results show that the nut factor for the EHB is higher than that of standard bolts and bolt relaxation is not affected by the concrete presence during the hardening stage. Adequate friction coefficients were proposed as well as an equation for calculating the residual preload of the EHB. Resumen: Es necesaria una precarga inicial adecuada del perno para garantizar la resistencia y rigidez de las conexiones atornilladas. En este estudio, se utilizó un método experimental de control de torque para determinar la relación entre el torque de apriete y la precarga de nueve conexiones empernadas ciegas Extended Hollo-Bolt (EHB) a secciones huecas de acero rellenas de concreto (CFSHS). Para obtener los factores de tuerca EHB, que permiten calcular el nivel de precarga para cualquier valor de torque aplicado, se dibujaron curvas de torque versus precarga con base en los resultados experimentales y se llevó a cabo el método de ajuste de curvas. También se registró la relajación de la precarga de los pernos durante un período de 7 días mientras se producía el endurecimiento del hormigón. Además, se estableció un modelo 3D detallado de elementos finitos (FE) de la etapa de apriete del EHB. Los resultados experimentales y numéricos muestran que el factor de tuerca para el EHB es mayor que el de los pernos estándar y la relajación del perno no se ve afectada por la presencia del concreto durante la etapa de endurecimiento. Se propusieron coeficientes de fricción adecuados así como una ecuación para calcular la precarga residual del EHB.
Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Artículos
  • Temas:
  • Otros
  • Ingeniería

Compartir este contenido

Experimental and numerical analysis of preload in Extended Hollo-Bolt blind bolts = Análisis experimental y numérico de pretensión en Extended Hollo-Bolts

Copia el enlace o compártelo en redes sociales

Imagen de apoyo de  Thermogravimetric analysis of co-combustion of a bituminous coal and coffee industry by-products

Thermogravimetric analysis of co-combustion of a bituminous coal and coffee industry by-products

Por: Luis Eduardo; Ejim García Fernández | Fecha: 2022

Abstract: This study investigates the combustion characteristics of blends of bituminous coal (BC) with two by products of the coffee industry, spent coffee ground (SCG) and coffee husk (CH), at 10, 30, and 50 wt% using a thermogravimetric analyzer (TGA). For comparison purposes, blends of BC and wood pellets (WP) at the same mass ratios were also investigated. The thermal behavior and fuel interactions in the blends during combustion were characterized by the ignition index (Di), combustion index (S), and potential synergistic effects. The interactions between the materials in the blends led to an enhancement of up to 93.5% and 128.5% in Di, and 175.2% and 96.35% in S of the bituminous coal when blended at 50 wt% with SCG and CH, respectively. Furthermore, clear synergistic effects were observed with the combustion of BC-SCG blends, whereas the combustion of BC-CH blends did not show any appreciable synergistic effects.
Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Artículos
  • Temas:
  • Otros
  • Ingeniería

Compartir este contenido

Thermogravimetric analysis of co-combustion of a bituminous coal and coffee industry by-products

Copia el enlace o compártelo en redes sociales

Imagen de apoyo de  Co-combustion of coal and biomass in a fluidised bed reactor

Co-combustion of coal and biomass in a fluidised bed reactor

Por: Luis Eduardo García Fernández | Fecha: 2019

Abstract: The aim of this research was to investigate the combustion behaviour of coal and biomass blends using a pilot-scale bubbling fluidised bed reactor. The blends were prepared with a traditionally used biomass fuel (i.e. wood) and selected rich in alkali-metals biomass fuels (i.e. wheat straw and spent coffee grounds (SCG)) to investigate the potential of SCG as a fuel and the effect of ilmenite on agglomeration tendency when used as an additive and alternative bed material. To elucidate the interaction between the fuels in the blends and the effect of ash composition, thermogravimetric and ash fusibility studies were performed looking at both the parent fuels and blends. Initially, thermogravimetric studies focused on understanding the thermal decomposition of coal blended with by-products (spent coffee ground (SCG), and coffee husk (CH)) of coffee crop. Blends with wood were included for comparison purpose. The blends were prepared by blending coal with biomass at 10, 30 and 50 wt%. The experiments were performed under inert and oxidising conditions to elucidate the thermal behaviour and fuel interactions. The results showed that the inclusion of either spent coffee grounds or coffee husk in coal combustion can enhance the combustion performance. Indeed, the blends with spent coffee grounds were found to be more reactive than those with coffee husk and with similar characteristics to the blends with wood. It was attributed to the existence of synergistic effects. These results offer compelling evidence of the potential of by-products from the coffee crop, especially spent coffee grounds for energetic applications. The study of ash fusibility characteristics investigated the ash fusibility temperatures under oxidising conditions of coal ash blended with ash from spent coffee grounds. Blends with wheat straw ash were included for comparison purpose. Particular attention was paid to the blending ratio effect on ash fusibility temperatures. The results showed that SCG is an interesting fuel in co-processing due to the low ash content and high ash fusibility temperatures when blended with coal. The high ash fusibility temperatures of the blends were attributed to the high content of CaO, MgO, and P2O5 in SCG with negligible content of SiO2 and Cl, complementing the high content of Al2O3 and Fe2O3 in coal. Evidence from this study suggests that the high ash fusion temperatures in the blends of coal with spent coffee grounds can reduce the common operational issues related to biomass ash such as agglomeration. This can also provide confidence for large scale thermochemical conversion systems fuelled by such kind of coal and biomass blends to be able to maintain long-term stable operation. The final part of this research focused on co-combustion experiments in a pilot-scale BFB aiming to investigate the potential of SCG as a fuel, and ilmenite as an additive and alternative bed material. For comparison purpose blends of coal with wheat straw and wood pellets were also combusted in the same BFB reactor under similar combustion conditions. Similarly, kaolin and bauxite, and silica sand were compared to ilmenite when used as an additive and alternative bed material, respectively. The inclusion of biomass in coal combustion showed marked differences in the temperature profiles, gas emissions, and combustion performance. The results showed that coal and SCG blends can be combusted for energy applications with improved combustion efficiency compared to wheat straw and wood commercial pellets. Nevertheless, high N content in SCG represents a challenge in terms of NOx emissions that should be addressed.
Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Tesis
  • Temas:
  • Otros
  • Ingeniería

Compartir este contenido

Co-combustion of coal and biomass in a fluidised bed reactor

Copia el enlace o compártelo en redes sociales

Selecciona las Colecciones en las que vas a añadir el contenido

Para consultar los contenidos añadidos busca la opción Tus colecciones en el menú principal o en Mi perfil.

Mis colecciones

Cargando colecciones

¿Deseas limpiar los términos de la búsqueda avanzada?

Vas a limpiar los términos que has aplicado hasta el momento para poder rehacer tu búsqueda.

Selecciona las Colecciones en las que vas a añadir el contenido

Para consultar los contenidos añadidos busca la opción Tus colecciones en el menú principal o en Mi perfil.

Mis colecciones

Cargando colecciones