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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.
361

Wide bandwidth control of AC machines

Boast, G. S. January 1992 (has links)
No description available.
362

Loss measurements in the endwall region of a cascade of compressor blades at stall

Urban, Marlies C. 06 1900 (has links)
Approved for public release, distribution unlimited / Flow around second-generation controlled-diffusion blades in cascade at stall was investigated using fivehole probe surveys. Wake pressure surveys were conducted at various locations between the cascade centerline and endwall region. Corresponding inlet pressure surveys were also performed to allow the total pressure loss distribution to be calculated across the blades. A fully automated traverse mechanism was implemented for the probe surveys ahead of and aft of the cascade blades. The number of wake surveys conducted allowed the pressure distribution profiles to show pressure deficiencies at the endwall region in greater detail than previous studies.
363

Automated Controller Design for a Missile Using Convex Optimization / Automatisierter Reglerentwurf für einen Flugkörper unter Verwendung konvexer Optimierung

Auenmüller, Christoph January 2016 (has links)
The focus of the present master thesis is the automation of an existing controllerdesign for a missile using two aerodynamic actuating systems. The motivation isto evaluate more missile concepts in a shorter period of time.The option used is trimming and linearization of a highly nonlinear missile at specic conditions. According to these conditions, either a two-dimensional operatingpoint grid dened by Mach number and height or three-dimensional operatingpoint grid dened by Mach number, height and angle of attack is generated forthe whole operating range of the missile. The controllers are designed at thesepoints using convex optimization. The convex set denes the pole placement areawhich is constrained by linear matrix inequalities according to the dynamic behaviorof the missile at the operating point conditions. These controllers describea validity area where the missile can be stabilized. This area consists all neighboringoperating points and denes therefore the grid density which can dier atspecic regions of the operating range. Controlling the missile to the target makesit necessary to apply gain-scheduling in order to get the manipulated variable byinterpolation of adjacent operating points. During this blending of the controllersa problem called windup can occur when an actuator is saturated. This mightlead to instability in worst case but can be counteracted by a model-recovery antiwindupnetwork which guarantees stability in the presence of saturation. Thisanti-windup design is automated by an ane linear parameter dependency of thegrid parameters and has the same validity area like the controllers.The whole design was successfully developed and tested in MATLAB/Simulink onmissiles using one or two aerodynamic actuating systems. The controllers have agood performance at small and high acceleration steps and the anti-windup keepsthe missile stable even though the actuators are saturated. Stability and robustnessof the controllers and anti-windup networks was veried as well as an airdefense maneuver where the missile starts at the ground and intercepts a targetat high altitude was successfully simulated for dierent grids and missiles.
364

GPS assisted stabilization and tracking for a camera system

Johansson, Hugo, Kjellström, Hendric January 2017 (has links)
Today in most vehicles in battle, a camera system is used to manually lock a target and maintaining visual of the target as the vehicle is moving. In order to simplify this, this thesis investigates the approach to semi-automate the process by first manually locking the target and then let the camera approximate the trajectory of the enemy vehicle. In this thesis, the enemy vehicle is not moving. The ability to provide a truthful simulation environment for testing is crucial and will be discussed in this thesis along with three different estimators derived from the Kalman filter. Parameter identification and dynamic modelling of the camera are also presented that serves as a basis for the part of automatic control and for the experiments on the hardware. The simulation environment gave promising results when locating the target based on angle and radius estimation. By simulating a human operator, big deviations from the true value was no longer a problem since its purpose is to take over and steer the camera to the correct value. After gathering results from the simulations, Model-Based Design made it possible to test the algorithms in real life. The biggest challenge was to produce lifelike motions to test the hardware on and therefore made it harder to conclude the end result for the experiments carried out by the hardware on the moving platform.
365

A Study of Numerically Controlled Machines

Chan, John C. H. 08 1900 (has links)
This is a study of numerical control, its application, and the design of a numerical control program for a drilling machine. The study sought to obtain information on the function of numerical control; the different types of numerical control used by industry; and, the advantages of using numerical control.
366

IP Router Testing, Isolation and Automation

Peddireddy, Divya January 2016 (has links)
Context. Test Automation is a technique followed by the present software development industries to reduce the time and effort invested for manual testing. The process of automating the existing manual tests has now gained popularity in the Telecommunications industry as well. The Telecom industries are looking for ways to improve their existing test methods with automation and express the benefit of introducing test automation. At the same time, the existing methods of testing for throughput calculation in industries involve measurements on a larger timescale, like one second. The possibility to measure the throughput of network elements like routers on smaller timescales gives a better understanding about the forwarding capabilities, resource sharing and traffic isolation in these network devices. Objectives. In this research, we develop a framework for automatically evaluating the performance of routers on multiple timescales, one second, one millisecond and less. The benefit of introducing test automation is expressed in terms of Return on Investment, by comparing the benefit of manual and automated testing. The performance of a physical router, in terms of throughput is measured for varying frame sizes and at multiple timescales. Methods. The method followed for expressing the benefit of test automation is quantitative. At the same time, the methodology followed for evaluating the throughput of a router on multiple timescales is experimental and quantitative, using passive measurements. A framework is developed for automatically conducting the given test, which enables the user to test the performance of network devices with minimum user intervention and with improved accuracy. Results. The results of this thesis work include the benefit of test automation, in terms of Return on Investment when compared to manual testing; followed by the performance of router on multiple timescales. The results indicate that test automation can improve the existing manual testing methods by introducing greater accuracy in testing. The throughput results indicate that the performance of a physical router varies on multiple timescales, like one second and one millisecond. The throughput of the router is evaluated for varying frame sizes. It is observed that the difference in the coefficient of variance at the egress and ingress of the router is more for smaller frame sizes, when compared to larger frame sizes. Also, the difference is more on smaller timescales when compared to larger timescales. Conclusions. This thesis work concludes that the developed test automation framework can be used and extended for automating several test cases at the network layer. The automation framework reduces the execution time and introduces accuracy when compared to manual testing. The benefit of test automation is expressed in terms of Return on Investment. The throughput results are in line with the hypothesis that the performance of a physical router varies on multiple timescales. The performance, in terms of throughput, is expressed using a previously suggested performance metric. It is observed that there is a greater difference in the Coefficient of Variance values (at the egress and ingress of a router) on smaller timescales when compared to larger timescales. This difference is more for smaller frame sizes when compared with larger frame sizes.
367

Kriterier för automation vid inlagring : Ett beslutsunderlag i valet av artikelplacering / Criteria for automation during the put away process.

Svensson, Simon, Wadsten, Adam January 2019 (has links)
The role of warehouse in the value stream, plays a significant part in how well a company can satisfy the requirements of a customer. To be able to support the demand of the customers, production companies are forced to produce a bigger variety of models in the product range, which results in an increasing assortment. With an effective stock keeping, there is a potential to reduce waste and increase profitability. In the choice of warehouse-design, warehouse-operations have the opportunity of choosing between a number of different designs containing manual and automated put away.It has become common that companies are choosing a combination of automated and manual processes. With this combination of processes, the companies are faced with choices about stock locations. With the help of well developed criterias about stock locations, there is a potential to achieve a more effective put away. The purpose of the study has been formulated as ”Investigate when automation in warehouse management makes the put away process in a central warehouse more efficient”.   Through a case study on a warehouse, located in Nässjö, this report will answer the research questions regarding which of the manual and automated put away processes to use. The research questions are: Which criteria affect the decision of automated or manual put away? Based on the criteria that are raised in research question 1, when is it more efficient to store carton in AS/RS in comparison with manual picking with truck in pallet racking? The research questions wish to lift criteria as a basis for decision making and when it is more effective to use automated put away. The warehouse that this study is based on is using both automated and manual materials handling. The specific automation system that has been the basis for this study’s result is AutoStore. This report has a qualitative approach, the methods that has been used for collecting data are interviews, observations and document studies.   Dimension, process time and utilization were the three criteria that are presented in the result. Based on the pallets limit of space in the automated system, the dimension of the article is the first criteria. In addition to the article’s measurements, the articles shape and material of the package had an impact if the article would fit in the load carrier. The two put away processes include different operations that differ in how long they take to execute, which has an impact on the company's efficiency. One reason for the time consuming difference, turned out to be how the quantity affects the time for put away in AutoStore comparing with the constant time for manual put away. A time consuming operation in the process with AutoStore was the one with repacking for the systems pallet. The operation also turned out to affect the utilization rate, due to its measurement of a pallets fill rate.  The quantity of put away in combination with the dimensions of the article, affects the total utilization rate.   With the result, the aim of the study is to contribute to companies that contains a combination of warehouse-design with a basis for the decision making about stock locations.
368

Robust controller specification and design for a run-of-mine milling circuit

Craig, Ian Keith January 1993 (has links)
A thesis submitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy. / A new approach to the problem ofdesigning a control system for a run-of-mine (ROM) milling circuit is described. The ROM mill control problem is formalized in terms or a general linear system synthesis and analysis framework. Using this framework, u-synthesis and analysis is applied to a model of an industrial ROM milling circuit. The milling circuit uncertainty structure is obtained from plant perturbation tests. Correlations of plant parameter uncertainties and the choice of the location of uncertainty weights within the plant transfer function matrix structure, are discussed. Some comments are made as to possible sources of the plant uncertainties, and practical measures that can be taken to minimize them. The choice of performance weighting functions is discussed with regard to the economic and process-related importance of each plant output and issues of implementation such as the sampling rate to be used. A u-controller is obtained which provides robust performance in the face of significant model uncertainties. This controller is tested on a real industrial ROM milling circuit It is shown that the u-controller could be made to work on an industrial plant. Practical problems encountered are discussed, and reasons are given as to why the behaviour of the physical system differs form that observed in computer simulations. (Abbreviation abstract) / AC 2018
369

An Introduction to the DevOps Tool Related Challenges

Bheri, Sujeet, Vummenthala, SaiKeerthana January 2019 (has links)
Introduction : DevOps bridges the gap between the development and operations by improving the collaboration while automating the as many as steps from developing the software to releasing the product to the customers. To automate the software development activities, DevOps relies on the tools. There are many challenges associated with the tool implementation such as choosing the suitable tools and integrating tools with existed tools and practices. There must be a clear understanding on what kind of tools are used by the DevOps practitioners and what challenges does each tool create for them. Objectives: The main aim of our study is to investigate the challenges faced by the DevOps practitioners related to the tools and compare the findings with the related literature. Our contributions are (i) a comprehensive set of tools used by Developers and Operators in the software industries; (ii) challenges related to tools faced by the practitioners; and (iii) suggested recommendations and its effectiveness to mitigate the above challenges. Methods: we adopted case study for our study to achieve our research objectives. We have chosen literature review and semi-structured interviews as our data collection methods. Results: In our study we identified seven tools used by developers and operators which were not reported in the literature such as Intellij, Neo4j, and Postman. We identified tool related challenges from the practitioners such as difficulty in choosing the suitable tools, lack of maturity in tools such as Git, and learning new tools. We also identified recommendations for addressing tool related challenges such as Tech-Talks and seminars using complementary tools to overcome the limitations of other tools. We also identified benefits related to the adoption of such recommendations. Conclusion: We expect the DevOps tool landscape to change as old tools either become more sophisticated or outdated and new tools are being developed to better support DevOps and more easily integrate with deployment pipeline. With regard to tool related challenges literature review as well as interviews show that there is a lack of knowledge on how to select appropriate tools and the time it takes to learn the DevOps practices are common challenges. Regarding suggested recommendations, the most feasible one appears to be seminars and knowledge sharing events which educate practitioners how to use better tools and how to possible identify suitable tools.
370

Diagnóstico e proposta de modelo de avaliação operacional para automoção em terminais de contêineres no Brasil. / Diagnosis and proposal of operational evaluation model of automation in container terminals in Brazil.

Patricio, Marcelo 08 October 2014 (has links)
Este trabalho apresenta um diagnóstico da questão de automação em terminais de contêineres no Brasil, assim como oferece uma proposta de um modelo que permita auxiliar a reflexão no momento da tomada de decisão na escolha da automação de equipamentos e/ou de processos que compõem as principais atividades de um terminal de contêineres. O processo de automação é recente na indústria portuária, teve seu início na década de 90 em países europeus cujos custos laborais eram altíssimos e necessitavam aumentar a produtividade e experimentar inovações. O modelo apresentado pretende ser uma proposta de análise expandida, isto é, um conceito amplo, que não verifique apenas análises financeiras, mas outros aspectos pertinentes à gestão e planejamento de um terminal, indicados por meio de um conjunto de variáveis. A saber: Layout existente ou proposto do terminal, Investimento financeiro CAPEX e OPEX, Confiabilidade dos sistemas de automação, Integração com sistemas de Tecnologia da Informação e Inteligência de Equipamento, em especial com os Sistemas de Operações dos Terminais, mas conhecidos como TOS (Terminal Operating System), Organização do trabalho e alterações de procedimentos operacionais, Contribuição para a segurança e meio ambiente, Obrigatoriedade legal do uso de automação, Custo e Intensidade do uso de mão de obra. A contextualização do setor e evolução da automação na indústria portuária; assim como um quadro atual da situação (diagnóstico) de automação dos terminais brasileiros será apresentada. Posteriormente, a revisão bibliográfica do tema com os principais artigos nacionais e internacionais. Todo esse arcabouço busca demonstrar o hiato existente entre os estágios automatizados e não automatizados; indicar os principais entraves existentes na implantação da automação por processo existente; promover a discussão da viabilidade desses terminais entre operadores, armadores, clientes e demais intervenientes em termos de produtividade, eficiência e de custos. A delicada questão da mão de obra avulsa não foi considerada uma variável restritiva do modelo por diversas razões: pois por si só seria restrição de implantação da automação pela reserva de mercado, especialmente para avulsos; ela permeia diversos itens listados anteriormente. Ao final dessa tese, além do diagnóstico de automação no país e de uma proposta de modelo para a tomada de decisão; espera-se contribuir a pesquisa e ao ensino da engenharia e áreas de gestão indicando do grau e desenvolvimento tecnológico na área de automação especificamente para terminais de contêineres. E, por derradeiro, fomentar uma reflexão sobre a profundidade das mudanças operacionais e organizacionais do trabalho que podem ocorrer. / This study aims a diagnosis of automation in container terminals in Brazil, and offers a proposal of model that allows assist the reflection at the time of decision making in the choice of automation equipment and/or processes that compose the main activities of a container terminal. The automation process is recent into port industry, beginning in the 90s in European countries whose labor costs were very high and needed to increase productivity and test innovations. The model to be presented is intended to be a proposal for expanded analysis, ie, a wide concept, which not only make financial analysis, but others relevant to the terminal management and planning, indicated by a set of variable features. Namely: existing or proposed layout, Financial Investment CAPEX and OPEX, Reliability of automation systems, integration of Information and Intelligence hardware technology systems, in particular with the Terminal Operating System (TOS), organization of work and changes in Standards Operating Procedures, Contribution to safety and the environment, legal obligation of the use of automation, cost and intensity of use of labor. The contextualization of the sector and the evolution of automation in the port industry; as the current situation (diagnosis) of Brazilian container terminals will be presented. Subsequently, the literature review of the topic with the main national and international articles. All this framework seeks to demonstrate the gap between automated and non-automated stages; indicate the main barriers in implementation of automation for existing process; further discussion of the viability of these terminals to operators, shipowners, customers and others stakeholders in terms of productivity, efficiency and cost. The delicate issue of dock workers was not considered a restrictive variable model for several reasons: it alone would restriction deployment automation by booking deployment automation, especially for dockers pool; it permeates many items listed above. At the end of this thesis, in addition to the diagnosis of automation in the country and a proposed model for decision making; is expected to contribute to research and education in engineering and management areas indicating the degree and technological development in automation specifically for container terminals. And at last, to promote reflections on the depth of operational and organizational job changes that may occur.

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