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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.
1

Avaliação da aderência de práticas de armazenagem de resinas termoplásticas aos princípios da mentalidade enxuta

Silva, Brian 22 September 2008 (has links)
Made available in DSpace on 2015-03-05T17:04:34Z (GMT). No. of bitstreams: 0 Previous issue date: 22 / Nenhuma / Considerando a premente importância dos custos, o alto volume de produção e a geração de altos níveis de estoques inerentes ao processo produtivo de resinas petroquímicas, o presente estudo analisa as práticas de armazenagem no setor sob a ótica dos princípios da Mentalidade Enxuta. Este trabalho tem por objetivo apresentar o grau de aderência das operações de armazenagem de resinas termoplásticas aos princípios da Mentalidade Enxuta, a saber: (i) especificação do valor; (ii) identificação da cadeia de valor; (iii) fluxo; (iv) estabelecimento da produção puxada; e (v) perfeição. Para tanto foi desenvolvido um instrumento de avaliação, desmembrado em cada um dos cinco princípios, apoiado por um grupo focado com especialistas nas operações estudadas. Na seqüência, o instrumento foi aplicado a profissionais da área em três armazéns do Pólo Petroquímico de Triunfo/RS, de onde se extraiu o grau de aderência das práticas de armazenagem aos princípios da Mentalidade Enxuta e as lacunas existentes. A seguir as lacuna / The present study analyses storage practices in the petrochemical sector from the point of view of Lean Thinking, taking into consideration the pressing importance of costs, the high volume of production and high volume of inventory intrinsic to the process. The main objective of the study is to present the level adherence that the operations of thermoplastic resin storage have to the principles of the Lean Thinking. The evaluation process developed was broken down into five different sections, one for each of the Lean Thinking principles. Each section had the support by a specialist in the specific field. Following that, the process was applied to professionals of the different areas in three warehouses of the Petrochemical Region of Triunfo/RS, from where it was possible to derive the level of adherence so mentioned, and the existing gaps. Finally, the gaps were jointly analyzed, and operational alternatives to fulfill them in order to better improve the adherence of the entire process to the principles
2

Řízení zásobní funkce nádrže s využitím metod umělé inteligence / Management of water reservoir storage function using methods of artificial intelligence

Urbanec, Patrik January 2020 (has links)
The subject of this thesis is to control the storage function of the reservoir using artificial intelligence methods, including the construction of the appropriate control algorithm. The thesis is divided into the theoretical part and the part of the application of reservoir storage function control. The theoretical part describes the control algorithm and the prediction model. The following are basic optimization methods and artificial intelligence methods. The second part presents the historical data used for the prediction model. The following is a description of calibration and validation of the control module and evaluation of the application results. Finally, there is a comparison and summary of individual results, control algorithm and prediction model. According to the results, the control algorithm can be recommended for further investigation.
3

Vodohospodářské řešení nádrže Vlachovice na vodním toku Vlára / A Water Management Analysis of the Vlachovice Reservoir on the Vlára Watercourse

Rajsiglová, Veronika January 2017 (has links)
The thesis focuses on a process of water management analysis of storage and protective function of the Vlachovice reservoir on the Vlára watercourse. The work contains an alternative proposal of the reservoir storage volume in Microsoft Excel, spreadsheet program with accessible functions whereby progression of arithmetic and logical algorithm simulating operation of reservoir storage function is created. An alternative proposal of protective volume of the reservoir is created in HYDROG program, where calculations of transformation of flood waves for PV 100, PV 1 000, and PV 10 000 are performed. Moreover, the work includes simplified analysis of the hydropower potential of the proposed reservoir.
4

Stabilization of a class of nonlinear systems with passivity properties / Stabilisation d'une classe de systèmes non linéaires avec propriétés de passivité

Borja Rosales, Luis Pablo 06 July 2017 (has links)
Dans cette thèse, nous abordons le problème de la stabilisation des systèmes non linéaires. En particulier, nous nous concentrons sur les modèles où l'énergie joue un rôle fondamental. Ce cadre énergétique est adapté pour capturer les phénomènes de plusieurs domaines physiques tels que les systèmes mécaniques, les systèmes électriques, les systèmes hydrauliques, etc. Le point de départ des contrôleurs proposés sont les concepts de système passif, des sorties passives et des fonctions d'énergie (ou stockage). Dans ce travail, nous étudions deux classes de systèmes dynamiques, à savoir les Hamiltoniens à ports (PH) et les Euler-Lagrange (EL), qui conviennent pour représenter de nombreux processus physiques. Une première étape vers la construction des contrôleurs est de montrer la passivité des systèmes PH et la caractérisation de leurs sorties passives. Par la suite, nous explorons l'utilisation des différentes sorties passives dans deux techniques bien connues de contrôle par passivité (PBC), c'est-à-dire le contrôle par interconnexion (CbI) et l'équilibrage énergétique (EB), et nous comparons les résultats obtenus dans les deux approches. De plus, nous proposons une nouvelle méthodologie dans laquelle la loi de commande est composée d'un terme proportionnel (P), un terme intégral (I) et, éventuellement, un terme dérivatif (D) de la sortie passive. Dans cette stratégie, l'énergie du système en boucle fermée est façonnée sans qu'il soit nécessaire de résoudre des équations différentielles partielles (PDE). Nous analysons le scénario du régulateur PID à l'aide des différentes sorties passives précédemment caractérisées. Enfin, nous appliquons un schéma PID-PBC récemment proposé dans la littérature à un système mécanique complexe, à savoir un pendule inversé ultra flexible, représenté sous la forme d'un modèle contraint EL. La conception du contrôleur, la preuve de stabilité, ainsi que les simulations et les résultats expérimentaux sont présentés pour montrer l'applicabilité de cette technique aux systèmes physiques. / In this thesis we address the problem of stabilization of nonlinear systems. In particular, we focus on models where the energy plays a fundamental role. This energy-based framework is suitable to capture the phenomena of several physical domains, such as mechanical systems, electrical systems, hydraulic systems, etc. The starting point in the proposed controllers are the concepts of passive system, passive outputs and energy (storage) functions. In this work we study two classes of dynamical systems, namely port-Hamiltonian (PH) and Euler-Lagrange (EL), which are suitable to represent many physical processes. A first step towards the controller design is to show the passivity of the PH systems and the characterization of their passive outputs. Thereafter, we explore the use of the different passive outputs in two well-known passivity-based control (PBC) techniques, that is control by interconnection (CbI) and energy balancing (EB), and we compare the obtained results in both approaches. In addition, we propose a novel methodology in which the controller consists in a proportional (P), an integral (I) and, possibly, a derivative (D) term of the passive output. In this approach the energy of the closed-loop system is shaped without the necessity of solving partial differential equations (PDEs). We analyze the scenario of the PID controller using the different passive outputs previously characterized. Finally, we apply a PID-PBC scheme recently proposed in the literature to a complex mechanical system, namely an ultra flexible inverted pendulum, which is represented as a constrained EL model. The controller design, the stability proof, as well as simulations and experimental results are presented to show the applicability of this technique to physical systems.
5

Automatizace řešení zásobní funkce vodohospodářské soustavy / Automation Solution of Storage Function of Water Management System

Menšík, Pavel January 2012 (has links)
The impact of climate changes on various sectors of human activity and preparation of mitigation and adaptation measures are becoming an important subject of global policy, thus also the policy of the Czech Republic. According to the research results, the impact of climate changes on minimum discharges is very significant and indicates a threat to storage function of water sources, without adequate accumulation for period of drought. One of the ways of preventing or completely avoiding the appearance of these problems is the construction of new reservoirs or the re-evaluation of the size of the storage and protective capacity of existing reservoirs. In relation to climate changes and their impact on the water yield there is a growing need for the participation of operative control progressive methods of reservoir storage function today. The dissertation thesis is aimed at storage function of water management system. Aim of the dissertation work is to create program with graphical user interface, which allows solving the storage function of water management system. Program allows automatically set up optimization and simulation model of any water supply system and solve of optimal control and optimal development of the water supply system. The program was verified on the selected water supply subsystem.
6

Možnosti řízení zásobní funkce nádrže / Possibilities of reservoir storage function control

Pruch, David Unknown Date (has links)
Stochastic control of large open water reservior stock fiction with operates a given variance of flow values a certain probability distribution. Stochastic forecasting models for stochastic management were compiled as part of the thesis. The stochastic procedure has the choice of the procedur efor a certain probability scenário as aópposed to the deterministic procedure. The probability election is provided by a fan of options. The thesis deals with the construction and subsequent evalution of stochastic management of the reservoir fiction. Using stochastic models management was performed with some probability of exceeding the controlled watr outflow from the large open water reservior. The simulation took place an a fictional large open water reservior. Subsequently a comparsion was made between management using individual methods and using forecats. Stochastic kontrol performed the large open water reservoir´s stock fiction well. At the end of the diploma thesis the best settings for each forecast and kontrol model were selected.
7

Stochastické řízení zásobní funkce nádrže s pomocí metod umělé inteligence / Stochastic management storage function of water reservoir using method of artificial intelligence

Kozel, Tomáš Unknown Date (has links)
The main advantage of stochastic forecasting is fan of possible value, which deterministic method of forecasting could not give us. Future development of random process is described better by stochastic then deterministic forecasting. We can categorize discharge in measurement profile as random process. Stochastic management is worked with dispersion of controlling discharge value. In thesis is described construction and evaluation of adaptive stochastic model base on fuzzy logic, neural networks and evolution algorithm, which are used stochastic forecast from forecasting models described in thesis. The learning fuzzy model and neural network is used as replacement of classic optimization algorithm (evolution algorithm). Model was tested and validated on made up large open water reservoir. Results were evaluated and were compared with model base on traditional algorithms, which was used for 100% forecast (forecasted values are real values). The management of the large open water reservoir with storage function, which was given by stochastic adaptive managing, was logical. The main advantage of fuzzy model and neural network model is computing speed. Classical optimization model is needed much more time for same calculation as fuzzy and neural network model, therefore classic model used clusters for stochastic calculation.

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