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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.
191

Estimation of Blocked Forces in an Assembly with Rear Drive Unit as a Source

Bala, Srujeeth Khanna January 2021 (has links)
Experimental validations are widely used for studying dynamic structural behaviors and these studies involve defining the structures completely as being used in real time. While in numerical simulations such detailed features are not specified to ease the computation, thereby deviating from accurate results. Hence experimental validations are more desired in product developments process. Applications of experimental verification for noise and vibration (referred to as NVH inautomotive industry) are expanding over the last few decades. Researchers are exploring ways to predict the responses on the new receiver using receiver independent forces, which led to evolution of component based TPA (Transfer Path Analysis) concept. The Component based TPA concept is an important development in automotive industry. It allows the auto manufacturers to make use of their available subsystems (like motor or a gearbox) in their newly developing vehicles. This has been made possible by defining the dynamic forces exerted by the source independent of receiving structure, which are then used to predict the responses on the new receiver. Evaluation of such receiver independent forces allows measurements to be made in a test rig rather than in the vehicle. This indeed helps in better communication between different departments or between suppliers and vehicle manufacturers, saves design iterations and time, and would help vehicle manufactures to predict the vehicle structural behaviors much before the first prototype is made. The method is based on the international standard ISO 20270:2019 (en) Acoustics – Characterization of sources of structure-borne sound and vibration – indirect measurement of blocked forces. The thesis is based on evaluating the source characterized forces that are used for predicting responses on a new receiving structure. For this, different methods in TPA are explored and for the rear drive unit application, in-situ method is chosen. The source characterized forces also termed as blocked forces are computed in different test set up and a validation check is performed. The obtained results are also compared with FEM and useful conclusions are drawn. And finally contact forces evaluated by integrating the subsystems are compared to the contact forces derived from the source characterized forces. / Experimentell verifiering av dynamiska krafter och vibrationer som uppkommer i fordon innebär mätning av tids-, frekvens- och/eller varvtalsberoende kvantiteter. Numeriska beräkningar har utvecklats till en hög nivå, men kan ännu inte beskriva alla förlopp och detaljer som förekommer i de verkliga processerna. På grund av detta krävs det fortfarande mätningar som en del av produktionsutvecklingen. Valideringsmetoder för ljud och vibrationer har utvecklats mycket desenaste decennierna, och ett mål har varit att utveckla mätmetoder där de uppmätta krafterna från en komponent som bidrar till buller kan mätas på ett sätt som inte beror på den testrigg eller det fordon den mäts i. Komponentbaserad TPA Transfer Path Analysis är en analysmetod som är viktig inom fordonsindustrin. Den gör det möjligt för en tillverkare att använda modeller av existerande komponenter (t.ex. motorer eller växellådor) i modeller för nya fordon. En grundläggande förutsättning är att de krafter som mäts är oberoende av den mottagande strukturen, det vill säga fordonet. Om krafterna är oberoende av strukturen där de mäts innebär det att komponenten kan mätas i en test rigg på ett annat ställe (till exempel hos en underleverantör) och att tillgång till fordon inte krävs för karaktäriseringen. Det underlättar kommunikationen mellan olika delar av organisationen och mellan underleveratörer och tillverkare och bidrar till att prediktera ljud och vibrationer innan den första prototypen är tillgänglig. Den föreslagna metoden är baserad på den internationella normen ISO 20270:2019 (en) Acoustics – Characterization of sources of structure-borne sound and vibration – indirect measurement of blocked forces. Examensarbetet handlar om att utveckla en mätmetod för att kunna ta fram krafter genererade av komponenter som är oberoende av testriggens egenskaper. De framtagna krafterna kan då användas i en virtuell fordonsmodell för att se ljud och vibrationsbidragen på fordonsnivå. Källan som har studerats är en slutväxel (rear drive unit) för fyrhjulsdrift i bil. Flera olikametoder för TPA har undersöks, och för karaktärisering av slutväxeln har in-situ metoden valts. Krafter som är oberoende av den mottagande strukturen kallas även ‘blocked forces’. Krafterna beräknas baserat på resultaten från flera olika delmätningar. Validering och även jämförelse medFEM beräkningar har gjorts liksom jämförelser mellan mätningar på enbart komponenten och av hela systemet.
192

Towards decision-making to choose among different component origins

Badampudi, Deepika January 2016 (has links)
Context: The amount of software in solutions provided in various domains is continuously growing. These solutions are a mix of hardware and software solutions, often referred to as software-intensive systems. Companies seek to improve the software development process to avoid delays or cost overruns related to the software development.   Objective: The overall goal of this thesis is to improve the software development/building process to provide timely, high quality and cost efficient solutions. The objective is to select the origin of the components (in-house, outsource, components off-the-shelf (COTS) or open source software (OSS)) that facilitates the improvement. The system can be built of components from one origin or a combination of two or more (or even all) origins. Selecting a proper origin for a component is important to get the most out of a component and to optimize the development.  Method: It is necessary to investigate the component origins to make decisions to select among different origins. We conducted a case study to explore the existing challenges in software development.  The next step was to identify factors that influence the choice to select among different component origins through a systematic literature review using a snowballing (SB) strategy and a database (DB) search. Furthermore, a Bayesian synthesis process is proposed to integrate the evidence from literature into practice.   Results: The results of this thesis indicate that the context of software-intensive systems such as domain regulations hinder the software development improvement. In addition to in-house development, alternative component origins (outsourcing, COTS, and OSS) are being used for software development. Several factors such as time, cost and license implications influence the selection of component origins. Solutions have been proposed to support the decision-making. However, these solutions consider only a subset of factors identified in the literature.    Conclusions: Each component origin has some advantages and disadvantages. Depending on the scenario, one component origin is more suitable than the others. It is important to investigate the different scenarios and suitability of the component origins, which is recognized as future work of this thesis. In addition, the future work is aimed at providing models to support the decision-making process.
193

FIRE DESIGN BY ADVANCED ANALYSIS OF ARCHETYPE STEEL-COMPOSITE STRUCTURE

Nimisha Dilip Jain (19200691) 26 July 2024 (has links)
<p dir="ltr">Fire is an extreme event that can lead to failure of structural components and potentially collapse of the structural system or sub-systems. Currently, there are no comprehensive, research-based methodologies for performance-based fire structural design (PBFSD) of composite wall-to-floor connections subjected to gravity loads and realistic fire scenarios. The existing studies primarily focus on the performance of simple shear connections to steel columns, and lack approaches for structural design of floor systems and their connections to walls (wall-to-floor connections) at elevated temperatures. This study addresses the need for evaluating the performance of composite floor systems and composite wall-to-floor connections under fire loading and developing research-based approaches to conduct performance-based structural design of these systems at elevated temperatures.</p><p dir="ltr">This study aims to give a simpler design method for shear tab and single angle shear connections at elevated temperatures by specifying retention factors for steel yield strength, ultimate strength, bolt material strength, and weld metal strength at elevated temperatures. The connection limit state equations specified in AISC Specifications are modified to incorporate these factors for higher temperatures. Additionally, an archetype building is designed and one floor system is evaluated using Finite Element Analysis (FEA) to assess the robustness of the structure and its resistance to collapse using PBFSD.</p><p dir="ltr">It also discusses the application of fire protection materials for steel members to resist fire scenarios for specified durations. Various fire scenarios, including ventilation-controlled and fuel-controlled fires were evaluated to assess localized behavior at the connection points and the overall behavior of the structural compartment. The FE analyses included various fire scenarios, compartment locations (interior, edge, or middle), and fire protection scenarios (2-hour rating fire protection, or no fire protection on interior beams). The composite floor system is evaluated for a combination of these scenarios under fire and gravity loading.</p><p dir="ltr">Through this study, a comprehensive analysis of the behavior of composite floors systems and associated connections in SpeedCore Wall Systems (C-PSW/CF) under fire loading is achieved.</p>
194

Contribution à la spécification et à l’élaboration d’une plateforme de maintenance orientée connaissances / A contribution to the specification and the development of an oriented knowledge platform for maintenance

Karray, Mohamed Hedi 09 March 2012 (has links)
Le maintien en condition opérationnelle des équipements industriels est un des enjeux importants de l'entreprise, et a fait passer la maintenance d'un centre de coût à un centre de profit, ce qui a eu pour conséquence une éclosion de logiciels d'aide à la maintenance allant de la GMAO aux plateformes de e-maintenance. Ces systèmes d'aide fournissent aux différents acteurs de la maintenance, un support à la décision et un ensemble de services permettant une gestion informatisée d'activités de base appartenant au processus de maintenance (exemple l'intervention, la planification, le diagnostic, etc.). Toutefois, les besoins des utilisateurs évoluent dans le temps en fonction de nouvelles contraintes, de leur expertise, des nouvelles connaissances. Par contre les services fournis n'évoluent pas et nécessitent une réactualisation. Afin de tenir compte de l'évolution de ces connaissances, pour que ces systèmes d'aide puissent répondre aux besoins des utilisateurs et puissent proposer des services à la demande et des services évolutifs nous avons fait le point dans cette thèse sur les avantages et limites des systèmes informatiques d'aide existants notamment les plateformes de e-maintenance (systèmes les plus avancés aujourd'hui en maintenance). Pour pallier le manque des systèmes existants, nous avons proposé le concept de s-maintenance qui est caractérisé principalement par les échanges collaboratifs entre applications et utilisateurs, par des connaissances communes du domaine de maintenance. Pour mettre en œuvre ce concept, nous avons proposé une plateforme orientée connaissances assurant des fonctionnalités auto-x (auto-traçabilité, auto-apprentissage, autogestion) qui permettent de répondre aux caractéristiques de la s-maintenance. L'architecture à base de composants de cette plateforme prend appui sur une base de connaissances partagée entre les différents composants qu'elle intègre au profit de l'interopérabilité sémantique ainsi que de la capitalisation des connaissances. Nous avons par ailleurs développé une ontologie du domaine de maintenance sur laquelle s'appuie cette base de connaissances. Finalement, afin de développer les fonctionnalités auto-x assurées par la plateforme nous avons proposé un système à base de traces exploitant la base de connaissances et l'ontologie associée / Operational condition maintenance of industrial equipment is a principal challenge for the firm production. This fact transfer the maintenance from the cost center to the profit center which has lead to massif development of maintenance support system starting from the GMAO to the e-maintenance platform. These systems provide to the maintenance agent, decision-support, and set of services allowing a computerized management of core activities for maintenance process. (e.g. intervention, planning, diagnostic,...). However, the user request continues evolving in time with respect of their expertise, their renewed knowledge and new constraints. On the other hand, the existing services are not following their requirements and they need to be updated. In this thesis, an overview on the advantage and drawback of existing computerized support system, in particular the e-maintenance platform (the most advanced maintenance system) is presented in order to meet the users needs and propose scalable and on-demand services. To overcome the existing system shortage, we propose the s-maintenance concept characterized by the collaborative exchange between users and applications and the common knowledge of the maintenance field. Thus, to implement this concept, a knowledge-oriented platform is proposed providing the auto-x functionalities (auto-traceability, auto-learning and auto-management) and meeting the s-maintenance characteristics. The architecture based on components of this platform, is also based on shared knowledge between integrated components for the benefit of the semantic interoperability as well as for the knowledge capitalization. Maintenance domain ontology is also developed on which the knowledge base is rested. Finally, in order to develop the auto-x functionalities, provided by the platform, a trace-based system is proposed by exploiting the knowledge base and the associated ontology.
195

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.
196

BEHAVIOR AND DESIGN OF FLOOR TO SPEEDCORE WALL CONNECTIONS UNDER FIRE LOADING

Muhannad Riyadh Alasiri (17086912) 10 October 2023 (has links)
<p dir="ltr">Composite Plate Shear Wall/ Concrete Filled (C-PSW/CF), also referred to as SpeedCore walls, are being used as innovative shear wall commercial high-rise buildings. These walls offer advantages such as modularity and construction schedule contraction. The cross-section of C- PSWs/CF consists of concrete infill sandwiched between the steel faceplates, where the steel plates are tied together by steel tie bars. Elevated temperatures will result in a deterioration in the mechanical properties of steel and concrete during a fire event in buildings. Such degradation can lead to stability-related failure of structural components. Composite floors are connected to these walls through simple shear connections. The floor-to-wall connections will be exposed to elevated temperatures, which may result in connection failure and progressive collapse of structures.</p><p dir="ltr">Designing SpeedCore walls without fire protection raises concerns regarding the performance of other structural components connected to SpeedCore walls under fire loading including composite floor systems and wall-to-floor connections. Numerical studies conducted on the connections and the floor systems indicated that these structural components undergo thermal compression forces during heating and tensile forces during the cooling phases of a fire event. The goal of this research was to develop an approach for performance-based fire resistance design of complete floor systems consisting of SpeedCore walls, composite floor slabs, and wall-to-floor connections.</p><p dir="ltr">This research includes experimental and numerical analyses to gain insight into the behavior of the floor-to-SpeedCore wall connections under fire and gravity loading. The specimens included steel beams connected to SpeedCore walls through simple shear connections. Three types of floor-to-wall connections were tested including connections with through-plate, reinforcing plate, and unreinforced plate. The parameters considered in the test matrix included: connection type, temperature, loading angle, and loading direction. These parameters in the test matrix were based on results obtained from previous numerical and experimental studies in the literature. The experimental results can fill the existing knowledge gap on floor-to-wall connections for steel-concrete composite members, develop design recommendations, and benchmark numerical models.</p><p dir="ltr">Numerical models were developed to simulate the behavior of the connections (member level) and whole structures (structure level) at ambient and elevated temperatures. Finite Element (FE) analysis and Component-based Models (CB) were utilized to develop the numerical models. The developed models were benchmarked by comparing the obtained numerical results with experimental data reported in the literature. FE models have been validated at two different levels, namely member level, and system level. The performance of the designed connection for the archetype structures was studied using benchmarked FE and CB models. The behavior of various wall-to-floor connections with different steel plate (C-PSW/CF) detailing was investigated.</p><p dir="ltr">Benchmarked numerical models were used to perform a parametric study to evaluate the performance of these connections. UP connection detail was used to perform the study due to its promising experimental performance, which does not need any special detail or plate reinforcement. The study was performed by evaluating the effects of critical parameters on the connection behavior namely, bolt size, target temperature, loading angles, and loading direction</p>
197

Streamlining Certification Management with Automation and Certification Retrieval : System development using ABP Framework, Angular, and MongoDB / Effektivisering av certifikathantering med automatisering och certifikathämtning : Systemutveckling med ABP Framework, Angular och MongoDB

Hassan, Nour Al Dine January 2024 (has links)
This thesis examines the certification management challenge faced by Integrity360. The decentralized approach, characterized by manual processes and disparate data sources, leads to inefficient tracking of certification status and study progress. The main objective of this project was to construct a system that automates data retrieval, ensures a complete audit, and increases security and privacy.  Leveraging the ASP.NET Boilerplate (ABP) framework, Angular, and MongoDB, an efficient and scalable system was designed, developed, and built based on DDD (domain-driven design) principles for a modular and maintainable architecture. The implemented system automates data retrieval from the Credly API, tracks exam information, manages exam vouchers, and implements a credible authentication system with role-based access control.  With the time limitations behind the full-scale implementation of all the planned features, such as a dashboard with aggregated charts and automatic report generation, the platform significantly increases the efficiency and precision of employee certification management. Future work will include these advanced functionalities and integrations with external platforms to improve the system and increase its impact on operations in Integrity360.

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