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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Probability modeling of industrial situations using transform techniques

Hu, Xiaohong January 1995 (has links)
No description available.
12

Análisis y simulación de un protocolo de comunicaciones para una red de sensores: aplicación en dispositivos de vuelo

Encinas, Diego 26 June 2013 (has links)
Esta tesis tiene como objetivo general desarrollar una herramienta para analizar/predecir condiciones de trabajo de una red de sensores. En particular, se enfoca a un conjunto de dispositivos de vuelo que son parte de sistemas aeroespaciales. El simulador es obtenido por medio de un modelado específico del sistema y su contrastación es realizada a través de un prototipo hardware. La herramienta propuesta permite conseguir medidas previas a la implementación de una etapa experimental definitiva de un dispositivo de vuelo. En particular, en los sistemas aeroespaciales, es necesario cambiar las condiciones de trabajo de los prototipos para predecir el comportamiento y posibles fallos durante la etapa de servicio del hardware definitivo. Conseguir estas condiciones de trabajo puede resultar muy costoso debido al valor de los dispositivos para generarlas. El modelo de simulación provee el medio para extrapolar posibles escenarios operativos sin contar con instrumentos físicos.
13

COMPARISON OF VARIABILITY MODELING TECHNIQUES

Akram, Asif, Abbas, Qammer January 2009 (has links)
Variability in complex systems offering rich set of features is a seriouschallenge to their users in term of flexibility with many possible variants fordifferent application contexts and maintainability. During the long period oftime, much effort has been made to deal with these issues. An effort in thisregard is developing and implementing different variability modelingtechniques.This thesis argues the explanation of three modeling techniques namedconfigurable components, feature models and function-means trees. The maincontribution to the research includes:• A comparison of above mentioned variability modeling techniques in asystematic way,• An attempt to find the integration possibilities of these modelingtechniques based on literature review, case studies, comparison,discussions, and brainstorming.The comparison is based on three case studies each of which is implemented inall above mentioned three modeling techniques and a set of generic aspects ofthese techniques which are further divided into characteristics. At the end, acomprehensive discussion on the comparison is presented and in final sectionsome integration possibility are proposed on the basis of case studies,characteristics, commonalities and experience gained through theimplementation of case studies and literature review.
14

Hydraulic conductivity measurement of permeable friction course (PFC) experiencing two-dimensional nonlinear flow effects

Klenzendorf, Joshua Brandon 04 October 2010 (has links)
Permeable Friction Course (PFC) is a layer of porous asphalt pavement with a thickness of up to 50 millimeters overlain on a conventional impervious hot mix asphalt or Portland cement concrete roadway surface. PFC is used for its driver safety and improved stormwater quality benefits associated with its ability to drain rainfall runoff from the roadway surface. PFC has recently been approved as a stormwater best management practice in the State of Texas. The drainage properties of PFC are typically considered to be governed primarily by two hydraulic properties: porosity and hydraulic conductivity. Both of these hydraulic properties are expected to change over the life of the PFC layer due to clogging of the pore space by trapped sediment. Therefore, proper measurement of the hydraulic properties can be problematic. Laboratory and field tests are necessary for accurately determining the hydraulic conductivity of the PFC layer in order to ensure whether the driver safety and water quality benefits will persist in the future. During testing, PFC experiences a nonlinear flow relationship which can be modeled using the Forchheimer equation. Due to the two-dimensional flow patterns created during testing, the hydraulic conductivity cannot be directly measured. Therefore, numerical modeling of the two-dimensional nonlinear flow relationship is required to convert the measureable flow characteristics into the theoretical flow characteristics in order to properly determine the isotropic hydraulic conductivity. This numerical model utilizes a new scalar quantity, defined as the hydraulic conductivity ratio, to allow for proper modeling of nonlinear flow in two-dimensional cylindrical coordinates. PFC core specimens have been extracted from three different roadway locations around Austin, Texas for the past four years (2007 to 2010). Porosity values of the core specimens range from 12% to 23%, and the porosity data suggest a statistical decrease over time due to trapped sediment in the pore space. A series of constant head tests used in the laboratory and a falling head test used in the field are recommended for measurement of PFC hydraulic characteristics using a modified Forchheimer equation. Through numerical modeling, regressions equations are presented to estimate the hydraulic conductivity and nonlinear Forchheimer coefficient from the measureable hydraulic characteristics determined during experimental testing. Hydraulic conductivity values determined for laboratory core specimens range from 0.02 centimeters per second (cm/s) to nearly 3 cm/s. Field measurements of in-situ hydraulic conductivity vary over a range from 0.6 cm/s to 3.6 cm/s. The results of this research provide well-defined laboratory and field methods for measurement of the isotropic hydraulic conductivity of PFC experiencing two-dimensional nonlinear flow and characterized by the Forchheimer equation. This methodology utilizes a numerical model which presents a proper solution for nonlinear flow in two-dimensions. / text
15

Comprehensive Evaluation and Proposed Enhancements of Tool Wear Models. : Integrating Advanced Fluid Dynamics and Predictive Techniques.

Azizi Doost, Peiman, Mehmood, Sultan January 2024 (has links)
This thesis investigates the current state of tool wear prediction models in machining, focusing on their limitations in accurately incorporating the complex dynamics of cutting fluids and their industrial applicability. It proposes a comprehensive evaluation framework to classify and evaluate a wide range of models, including empirical, physical, computational, and data-driven models. The study identifies the key limitations and strengths of each model category. It proposes enhancements by integrating advanced fluid dynamics and predictive modeling techniques to improve tool wear predictions' accuracy and industrial applicability. A structured literature review was conducted to investigate and evaluate existing tool wear models and their integration with cutting fluid dynamics. This review included defining search criteria, selecting relevant studies, and assessing their quality and relevance. The study uses thematic analysis and model evaluation frameworks to classify and evaluate the models, leading to the identification of critical limitations and strengths. The literature review and model evaluation findings revealed that empirical models, while simple and quick to implement, showed moderate accuracy and limited fluid dynamics integration. Physical models provided high accuracy in specific conditions but were computationally intensive. Computational models, particularly those using techniques like Finite Element Analysis (FEA) and Computational Fluid Dynamics(CFD), offered detailed insights and high accuracy but required significant computational resources. Data-driven models demonstrated exceptional predictive capabilities and comprehensive fluid dynamics integration but relied heavily on data availability and quality.  The proposed enhancements include introducing non-linear elements into empirical models, incorporating simplified fluid models or empirical correlations into physical models, exploring reduced-order models (ROMs) or surrogate models for computational models, and developing robust data preprocessing and augmentation techniques for data-driven models. These enhancements aim to improve the accuracy and applicability of tool wear models in industrial machining processes, ultimately contributing to more efficient and cost-effective machining operations. The study emphasizes the importance of a systematic and holistic approach to model evaluation and enhancement. Future research should focus on validating these proposed enhancements through empirical studies and real-world applications, ensuring their relevance and robustness in diverse industrial settings. This research offers significant potential to advance tool wear modeling, providing valuable insights for both academia and industry.
16

Разработка методики моделирования и оптимизации проектирования модульных Навесных Фасадных систем (НФС) в среде Autodesk Revit : магистерская диссертация / Development of a methodology for modeling and optimizing the design of modular Hinged facade systems (HFS) in the Autodesk Revit environment

Краснопеев, А. В., Krasnopeev, A. V. January 2024 (has links)
В данной работе рассматриваются проблемы, связанные с моделированием навесных вентилируемых фасадов и оптимизацией работы с ними в среде Autodesk Revit. Данная работа проведена с целью предложения решения по сокращению трудовых и временных затрат проектирования модульных навесных фасадных систем. Результатом работы является написание инструкции по моделированию НФС по модульной схеме и оценка эффективности проектирования с учетом оптимизации процессов проектирования модульных НФС. / This paper discusses the problems associated with modeling hinged ventilated facades and optimizing work with them in the Autodesk Revit environment. This work was carried out in order to propose a solution to reduce the labor and time costs of designing modular hinged facade systems. The result of the work is the writing of instructions for modeling HFS according to a modular scheme and evaluating the effectiveness of design, taking into account the optimization of the design processes of modular HFS.
17

Автоматизация процессов проектирования и моделирования Навесных Вентилируемых Фасадов (НВФ) с использованием среды Autodesk Revit : магистерская диссертация / Automation of the design and modeling of Hinged Ventilated Facades (HVF) using the Autodesk Revit environment

Спасенникова, А. А., Spasennikova, A. A. January 2024 (has links)
В данной работе рассматриваются проблемы, связанные с моделированием навесных вентилируемых фасадов и автоматизацией работы с ними в среде Autodesk Revit. Данная работа проведена с целью разработки скрипта для автоматизации расстановки фасонных элементов навесных вентилируемых фасадов. Для достижения цели были поставлены следующие задачи: рассмотреть степень изученности навесных фасадных систем в ТИМ, описать методику моделирования навесных фасадных систем по классической схеме, создать семейства откосов и отлива, написать скрипт и проверить его работоспособность. Результатом работы является Dynamo-скрипт, размещающий фасонные элементы, позволяющий уменьшить трудозатраты проектировщиков. / This paper discusses the problems associated with the modeling of hinged ventilated facades and automation of work with them in the Autodesk Revit environment. This work was carried out in order to develop a script for automating the placement of shaped elements of hinged ventilated facades. To achieve this goal, the following tasks were set: to consider the degree of knowledge of hinged facade systems in TIM, describe the methodology for modeling hinged facade systems according to the classical scheme, create families of slopes and low tide, write a script and check its operability. The result of the work is a Dynamo script that places shaped elements, which reduces the labor costs of designers.
18

Metodología y herramientas UML para el modelado y análisis de sistemas de tiempo real orientados a objetos

Medina Pasaje, Julio Luis 22 September 2005 (has links)
El objetivo de este trabajo es la definición de una metodología para la representación y análisis del comportamiento de tiempo real de sistemas que han sido diseñados utilizando el paradigma de orientación a objetos. La metodología que se propone, denominada UML-MAST, concilia las diferencias entre la visión del diseñador de sistemas de tiempo real y la del de sistemas orientados a objetos. A tal fin define un nivel de abstracción adecuado para los elementos de modelado del comportamiento de tiempo real, que permite formularlos con una estructura paralela a la arquitectura lógica del sistema, y vincularlos a esta. La semántica de modelado sigue el perfil UML para planificabilidad, rendimiento y tiempo (SPT) estandarizado por el OMG, del que UML-MAST puede considerase una implementación. La propuesta se integra con las herramientas de análisis y diseño de sistemas de tiempo real MAST (Modeling and Analysis Suite for Real-Time Applications), que analiza los modelos y retorna los resultados al modelo inicial para su interpretación por el diseñador. Asimismo, se han definido criterios para la extensión de esta metodología a otros niveles de abstracción tales como sistemas basados en componentes y sistemas implementados utilizando Ada 95. Parte de los resultados de este trabajo han sido incorporados por el OMG a su perfil SPT. / The main objective of this work has been the definition of a methodology for the representation and analysis of the timing behaviour of real-time distributed systems designed following the object oriented paradigm. The methodology proposed is called UML-MAST, and reconciles the mismatch between the visions of the object oriented designer and the real-time systems designer. To get this, it has been developed a particular level of abstraction that holds all the modelling elements needed to represent real-time behaviour, structuring the models following the logical architecture of the system. The semantics of the modelling elements follows the "UML Profile for Schedulability, Performance and Time" (SPT), a standard of the Object Management Group (OMG) to which this thesis has reported a number of contributions. UML-MAST can also be considered a particular specialization of its schedulability analysis sub-profile. UML-MAST is integrated in the framework of the Modeling and Analysis Suite for Real-Time Applications (MAST), a modelling environment with a set of tools that enable the analysis of a model and the recovery of its results in it. Criteria for the extension of the methodology to higher levels of abstraction have been defined. As examples, its extension to the modelling of component-based systems as well as to distributed systems developed with Ada95 have been explored and formulated.

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