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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.
21

Real-time state estimation of a distributed electrical power system under conditions of deregulation

Kusekwa, Mashauri A. D. January 2010 (has links)
Thesis (DTech (Electrical Engineering))--Cape Peninsula University of Technology, 2010. / Static state estimation is a mathematical procedure in which physical measurements from sub-stations and physical model are combined in an optimal way. That is, the measurements obtained from the sub-stations are used with the physical model and the states of the power system are selected or calculated such that the states match the measurements in some best way. The states of a power system are the bus voltage magnitude and voltage angle of each bus of the system. Static state estimation is an increasingly common part of electrical power utility energy management systems (EMS). It plays a critical part in a day-to-day operation of a power system utility. The system measurements obtained from static estimation are used for realtime operations like optimal power flow calculations and contingency analysis. Proper system operations with regards to avoidance of insecure conditions includes situational awareness, therefore, the static estimator plays an important role in power system security. A further motivation: in increasingly electrical power deregulation, more economic operations mean savings for customers and electrical power provider alike. Economic benefit might be realized if system operators have a more accurate situational awareness of the system through improved power system state estimator. The objective of the study was to develop method, algorithm and MATLAB program for solution of power system state estimation using parallel processing techniques. In achieving the objective, the study has concentrated on development of an approximate Tanzanian power system network model comprising of 30 buses and used as a case study; decomposing the bus admittance matrix of the model into 3 interconnected sub-systems; development of mathematical model for real and reactive power injections, real and reactive power flows in the transmission lines and tie-lines connecting the sub-systems; development of measurement data model for voltage magnitude, real and reactive power injections, real and reactive power flows; formulating of a constrained weighted least absolute value state estimation problem; development of decomposition-coordination method and algorithm; and formulating algorithm and MATLAB program for solving the constrained state estimation problem using parallel processing technique.
22

Identificação neuroanatômica de áreas cerebrais relacionadas à produção do canto em uma espécie de pássaro Suboscine da Amazônia (Myiozetetes cayanensis) / Neuroanatomical identification of cerebral areas related to the song production in a suboscine amazonian bird (Myiozetetes cayanensis).

Muriele Lobato Brito 27 February 2018 (has links)
A comunidade cientifica, ao longo dos anos, comprovou aprendizagem vocal em tres ordens de aves (papagaios, beija-flores e passeriformes oscines). Contudo, mais recentemente, estudos feitos em tres especies de Suboscines, Sayornis Phoebe, Procnias tricarunculata e Chiroxiphia linearis revelaram a existencia de um sistema rudimentar do canto e/ou extensivas variacoes vocais quantitativas e qualitativas entre as populacoes reprodutivas, sugerindo que estas especies sao capazes de aprender o seu canto. Esta evidencia incita a investigacao de outras especies de passaros Suboscines, visto que a distincao entre passaros aprendizes e nao-aprendizes vocais nao e tao obvia quanto se pensava. Uma especie de passaro Suboscines amazonica, Myiozetetes cayanensis, desperta o nosso interesse devido a complexidade estrutural do canto em dueto que pode inferir alguma aprendizagem do canto. Com o intuito de identificar as regioes de controle da producao do canto nestes animais nos utilizamos diferentes tecnicas de marcacao celular coloracao de Nissl, hibridizacao in situ radioativa e injecao de tracadores neuronais; ferramentas neuroanatomicas estas que nos forneceram pistas sobre a presenca de areas cerebrais potencialmente envolvidas no sistema de controle do canto. Dos tres nucleos envolvidos na producao do canto, conseguimos identificar apenas o nucleo hipoglosso - porcao traqueosiringeal (NXIIts) e somente atraves da injecao do tracador neuronal CTB. Identificamos o NXIIts tanto em macho quanto em femeas e ao quantificar os dados verificamos que o volume deste nucleo e 2 vezes maior nos machos do que nas femeas, inferindo um possivel dimorfismo sexual. Ao compararmos o volume total de NXIIts entre o nosso animal experimental e uma especie de passaro Oscine, Taeniopigia guttata, verificamos que este nucleo foi quase 2 vezes maior em Taeniopigia guttata machos e femeas. Nao foram identificados nucleos telencefalicos que se assemelhassem ao HVC e ao RA de Oscines por meio de nenhuma das tecnicas utilizadas, o que nos leva a concluir que, em Myiozetetes cayanensis, nao haja sistema de controle do canto e que seu canto seja inato / Along the years vocal learning has been repeatedly demonstrated in three bird orders (parrots, hummingbirds and the oscine songbirds). But recently some studies developed in three spicies of suboscine birds, Sayornis Phoebe, Procnias tricarunculata e Chiroxiphia linearis, demonstrated the existence of a rudmentary song system and/or extensive qualitative and quantitative vocal variations between reproductives populations suggesting that these species are capable of learning their songs. This evidence instigates the investigation of other suboscine songbirds spieces, since the distinction between learning and non-learning vocal birds is not that clear as thought. An amazon uboscine bird, Myiozetetes cayanensis, has attracted our attention due to the structural complexity of its duet song that may imply some vocal learning. Therefore, we tried to identificate the song control regions in this animals by means of different technics: Nissl staining, radioactive in situ hibridization and injections of neural tracers; neuroanatomical tools that provided important clues of cerebral areas implicated in the song system control. We identified only one of the three nuclei involved in the controlling of song production, the NXIIts and only by the injection of the neural tracer CTB. The NXIIts was identified both in males and females. When we quantified the data, we observed that the NXIIts was 2 times larger in males than in females, indicating a possible sexual dimorphism. We also compared the total volume of NXIIts between our experimental animal and a oscine species, Taeniopygia guttata. The volume of NXIIts was almost 2 times larger both in males and females of Taeniopigia guttata. We didint identified any nucleus that guards some resemblence to the oscine HVC or RA through none of the techniques that we tested. Therefore, we can assume that Myiozetetes cayanensis have no song control system and that their song are inate
23

Projeto de sistemas modulares de controle para sistemas produtivos. / Project of modular control systems for production systems.

Francisco Yastami Nakamoto 10 September 2008 (has links)
A competição no mercado globalizado, do ponto de vista do consumidor, aumentou consideravelmente a oferta de produtos e serviços, permitindo a escolha pela qualidade, preço, prazos e/ou disponibilidade. Entretanto, do ponto de vista das empresas, o desafio de atuar em um mercado saturado, dinâmico, competitivo e com aumento da demanda de produção orientado ao consumidor altera consideravelmente toda a estrutura da empresa. Desta forma, a flexibilidade torna-se um pré-requisito fundamental para que as empresas possam atuar neste mercado. Considerando-se o contexto apresentado, o objeto de estudo do presente trabalho são os Sistemas Produtivos Flexíveis (SPFs). Os SPFs são sistemas concebidos para atender às necessidades de um mercado dinâmico e competitivo. Isto causa complexidade no comportamento global desses sistemas exigindo diferentes propostas para o projeto de Sistemas de Controle de SPFs. A complexidade advém do fato de se perder a informação quanto ao pré-determinismo da seqüência de eventos que ocorrem no sistema global, além do fato de não existir previamente a definição de todos os processos de transporte com a designação prévia de todas as ordens de transporte que os transportadores presentes na planta devem executar. Neste contexto, o objetivo deste trabalho é apresentar como resultado uma proposta de sistema de controle modular para SPFs que atenda os requisitos de fluxo de informações envolvendo hierarquia e colaboração simultânea entre os módulos, respeitando a diversidade semântica presente na arquitetura. Apresenta-se então uma sistematização de projeto dos diversos módulos de controle e uma proposta de implementação de um algoritmo de designação dos transportadores para ser utilizado em tempo real permitindo a realização eficiente das atividades de transporte. / The competition in the globalized market increased considerably the demand for products and services to the customer point of view. However, the consumer\'s driven demand change the whole structure of the company. Thus, flexibility becomes an essential pre-requisite for companies to compete in the market. Considering the context presented, the object of study of this work is the Flexible Production System (FPS). The FPS must fulfill the needs on a dynamic and competitive market. This situation causes complexity in the overall performance of these systems, requiring different proposals for the design of the control systems. The complexity arises due to the fact that loses the information about the sequence of events that occur in the global system. Besides there is no previous exist definition for all processes of transport and prior designation for it. In this context, the objective of this work is to present a proposal for modular control systems to FPS that fits the requirements of information flow involving hierarchy and simultaneous collaboration between the modules. It will be presented systematization for the modular design of control as well as an implementation of an algorithm for designation of transport in real time leading to an efficient management of these activities.
24

Model-Based Control Development for an Advanced Thermal Management System for Automotive Powertrains

Merical, Kyle I. 09 August 2013 (has links)
No description available.
25

Optimal stopping for event-triggered sensing and actuation

Rabi, Maben, Johansson, Karl Henrik, Johansson, Mikael January 2008 (has links)
Novel event-triggered sensing and actuation strategies are presented for networked control systems with limited communication resources. Two architectures are considered: one with the controller co-located with the sensor and one with the control co-located with the actuator. A stochastic control problem with an optimal stopping rule is shown to capture two interesting instances of these architectures. The solution of the problem leads to a parametrization of the control alphabet as piecewise constant commands. The execution of the control commands is triggered by stopping rules for the sensor. In simple situations, it is possible to analytically derive the optimal controller. Examples illustrate how the new event-based control and sensing strategies outperform conventional time-triggered schemes. / <p>© 2008 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. Qc 20120220</p>
26

Comparison of polynomial profiles and input shaping for industrial applications

Pridgen, Brice 05 April 2011 (has links)
Command shaping creates reference commands that reduce residual vibrations in a flexible system. This thesis examines the use of command shaping for flexible system control in three industrial applications: cam-follower systems, sloshing liquids, and cherrypickers. One common type of command shaping is command smoothing which creates a smooth transition between setpoints. A specific type of command smoothing used in cam-follower systems is the polynomial profile. An alternative technique to reduce vibration in flexible systems is input shaping. In this thesis, input-shaped commands are compared to polynomial profiles for applications requiring both vibration suppression and fast motion. Simulation and experimental results show that input shaping is faster than polynomial profiles and provides a simple approach to suppressing residual vibration. Secondly, significant experimental contributions have been made in the area of slosh control. The oscillation of liquids in a container can cause liquid spillage or can cause stability issues, especially in space vehicles. In the past, a number of control techniques have been proposed, but only a few recommend the use of input shaping. This thesis describes the use of command shaping to limit slosh. Results are supported by numerical and experimental testing. Input-shaped commands reduce residual slosh amplitude compared to unshaped commands and polynomial profiles. Input-shaped commands can also accommodate uncertainties and changes in the sloshing frequencies. Lastly, a small-scale cherrypicker was constructed to study the use of input-shaping control on these types of aerial lifts. Cherrypickers have flexible dynamic effects that can cause dangerous and life-threatening situations. To study this class of machines and to provide future students an experimental testbed, several design criteria were established before construction began. The resulting machine achieved most design objectives, including a simple-to-use graphical user interface and accurate state measurements. Robust input-shaping controllers were implemented to limit endpoint vibration. The design of the cherrypicker is discussed and experimental results are reported.
27

Sensitivity-based Pricing and Multiobjective Control for Energy Management in Power Distribution Systems

January 2012 (has links)
abstract: In the deregulated power system, locational marginal prices are used in transmission engineering predominantly as near real-time pricing signals. This work extends this concept to distribution engineering so that a distribution class locational marginal price might be used for real-time pricing and control of advanced control systems in distribution circuits. A formulation for the distribution locational marginal price signal is presented that is based on power flow sensitivities in a distribution system. A Jacobian-based sensitivity analysis has been developed for application in the distribution pricing method. Increasing deployment of distributed energy sources is being seen at the distribution level and this trend is expected to continue. To facilitate an optimal use of the distributed infrastructure, the control of the energy demand on a feeder node in the distribution system has been formulated as a multiobjective optimization problem and a solution algorithm has been developed. In multiobjective problems the Pareto optimality criterion is generally applied, and commonly used solution algorithms are decision-based and heuristic. In contrast, a mathematically-robust technique called normal boundary intersection has been modeled for use in this work, and the control variable is solved via separable programming. The Roy Billinton Test System (RBTS) has predominantly been used to demonstrate the application of the formulation in distribution system control. A parallel processing environment has been used to replicate the distributed nature of controls at many points in the distribution system. Interactions between the real-time prices in a distribution feeder and the nodal prices at the aggregated load bus have been investigated. The application of the formulations in an islanded operating condition has also been demonstrated. The DLMP formulation has been validated using the test bed systems and a practical framework for its application in distribution engineering has been presented. The multiobjective optimization yields excellent results and is found to be robust for finer time resolutions. The work shown in this report is applicable to, and has been researched under the aegis of the Future Renewable Electric Energy Delivery and Management (FREEDM) center, which is a generation III National Science Foundation engineering research center headquartered at North Carolina State University. / Dissertation/Thesis / Ph.D. Electrical Engineering 2012
28

Switching Control Strategies for the Robust Stabilization of a DC-DC Zeta Converter / DC-DCゼータコンバータのロバスト安定化のためのスイッチング制御方策

Hafez, Bin Sarkawi 24 September 2021 (has links)
京都大学 / 新制・課程博士 / 博士(情報学) / 甲第23545号 / 情博第775号 / 新制||情||132(附属図書館) / 京都大学大学院情報学研究科数理工学専攻 / (主査)教授 太田 快人, 教授 山下 信雄, 教授 大塚 敏之 / 学位規則第4条第1項該当 / Doctor of Informatics / Kyoto University / DFAM
29

Řízení závlahového systému / Control of irrigation system

Farba, Marek January 2018 (has links)
This thesis deals with controlling the irrigation system. In the introduction there is a theoretical analysis of the irrigation units, the designed system and the programs used. The core of the paper is a description of the software development and visualization software developed. Subsequently, the process of designing printed circuit boards is described. The conclusion of the work is to verify the functionality of the irrigation system and the summary of the results achieved.
30

Systém pro řízení stínicí a vytápěcí techniky v budově / The System for Controlled Heating and Roller Blinds in the Building

Brudný, Tomáš January 2010 (has links)
The object of this project was to develop a device, which would by use to coordinate or control device wireless. The system divided to several independent devices, which assure high comfort for the user. The basic unit contains of touch panel which allow the user to control the system. The second unit is used for communication the system with GSM net. The third unit is used to coordinate the system from a PC. This unit makes possible data collection and their evaluation. This unit can as well control and coordinate any devises in the system. Part and parcel of this system are units which are used to drive the end consumers. The hole system is powered from a instead powers supply which is managed from a microprocessor. These devices make it possible, to the system to work without line voltage. The system is designed modular, so in the future it is possible to expand the system of others peripherals.

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