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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

Task-based data-acquisition optimization for sparse image reconstruction systems

Chen, Yujia, Lou, Yang, Kupinski, Matthew A., Anastasio, Mark A. 10 March 2017 (has links)
Conventional wisdom dictates that imaging hardware should be optimized by use of an ideal observer (TO) that exploits full statistical knowledge of the class of objects to be imaged, without consideration of the reconstruction method to be employed. However, accurate and tractable models of the complete object statistics are often difficult to determine in practice. Moreover, in imaging systems that employ compressive sensing concepts, imaging hardware and (sparse) image reconstruction are innately coupled technologies. We have previously proposed a sparsity-driven ideal observer (SDIO) that can be employed to optimize hardware by use of a stochastic object model that describes object sparsity. The SDIO and sparse reconstruction method can therefore be "matched" in the sense that they both utilize the same statistical information regarding the class of objects to be imaged. To efficiently compute SDIO performance, the posterior distribution is estimated by use of computational tools developed recently for variational Bayesian inference. Subsequently, the SDIO test statistic can be computed semi-analytically. The advantages of employing the SDIO instead of a Hotelling observer are systematically demonstrated in case studies in which magnetic resonance imaging (MRI) data acquisition schemes are optimized for signal detection tasks.
2

Inovace interního informačního systému Audiovizuálního centra Mendelovy univerzity v Brně

Schubert, David January 2011 (has links)
No description available.
3

Efektivnost záloh na jednocestné nápojové obaly v hospodářské praxi České republiky / Effectiveness of a deposit system on one-way containers in Czech republic

Slavík, Jan January 2003 (has links)
The reasons of the contemporaly regulation in the waste management regarding the theoretical basis (on that the regulation is built) are the main objectives of this work. Because of high induced costs of the erroneous state measures built on wrong expectations in the economy and because of less effectiveness and efficiency of these measures this analysis is very important. The test of induced costs should be accomplished on the example of the deposit system on one-way containers (PET bottles and cans), which should be implemented into the public law in the Czech republic in next few years. Hardly any measure in the waste management is provoking so intensive diskussion, as the deposit system on some beverages does. What is the main reason? Especially the rise of abatement costs by subjects influenced by the deposit system and the influence on the system of separate collection. The deposit system and the separate collection are competitive systems because of the reciprocal relationship. Regarding the driving forces of the regulation the main goal of this work is the modelling of costs and benefits of the deposit system in the Czech republic and the analysis of the decision making proces of affected subjects.
4

Modelling and control of advanced mechatronic system

Yan, Xiaomo January 2017 (has links)
Control of mechatronic systems remain an open problem in control theory despite the research work worldwide in the last decade. Uncertainties in mechatronic systems, which includes faults, and disturbance, will often cause undesired behaviours, affecting the systems performances, may lead to the system failure, or even causing safety issues. Control reconfiguration is an active approach in control systems field. However, controller reconfiguration involves changes in its parameters and structure. System stability might not be able to be guaranteed during the parameters tuning, which might cause more damage to system stability, sometimes may cause safety issues. Due the on-line reconfiguration has a scope, during which the system stability can not be guaranteed. This leads that the systems must be turned off during reconfiguration process. In many industrial areas, such as metallurgy, forging, and manufacturing, shutting down the streamline leads to significant levels of lost productivity and unacceptable economic losses. As alternative to control reconfiguration approach, in this thesis two methods are proposed to deal with faults and disturbances. The first method is the fault matrix observer and the second one is the set-point re-planning. The idea of both methods is to compensate the faults and disturbances which affect the system performances without changing the controller structure or controller parameters.
5

Racionalizace výrobních procesů v podniku / Rationalization of Production Processes in the Company

Novakov, Ivan January 2016 (has links)
The diploma thesis focuses on rationalization of manufacturing processes in company Honeywell Safety Products Partizanske s.r.o.. Main target is to track actual state of processes, which are connected to manufacturing activity, search for reasons of collisions and try to minimize or eliminate them. By designing of multiple optimization solutions, evaluating of data and after applying best-fitted solution can be collision eliminated on purpose. These solutions are exposed to economic analyse and possible share with Company. Economic perspective can help to easier identify which of solution could have bigger impact after implementation to support prosperity of mentioned company.
6

OPTIPAC: A User-Oriented Computer System for Optimization in Engineering Design

McDonald, John Franklin 05 1900 (has links)
<p> A description is given of the multi-technique nonlinear optimization system called OPTIPAC.</p> <p> The overall organization of the program is outlined and the significant features of each of the method subroutines are discussed. Considerable emphasis has been placed on the documentation for the system, and the two manuals which have been written are described briefly. The results of three test problems are included to demonstrate the value of having a variety of techniques in the package.</p> <p> A preliminary evaluation of OPTIPAC's performance is given, with relevant suggestions for further development.</p> / Thesis / Master of Engineering (MEngr)
7

Optimal operation & security analysis of power systems with flexible resources

Polymeneas, Evangelos 07 January 2016 (has links)
The objective of this research is to present a comprehensive framework for harnessing the flexibility of power systems in the presence of unforeseen events, such as those associated with component outages or renewable energy variability. Increased penetration of variable resources in the power grid, mainly in the form of wind and solar plants, has resulted in variable power flow patterns, increased thermal unit cycling and higher reserve capacity requirements. Furthermore, the variability of renewable energy output has increased the system’s ramping requirements and threatens the system’s voltage control capabilities. However, new sources of flexibility and network control are emerging to address these problems. Specifically, energy storage systems, demand side management, distributed energy resources and flexible transmission operation can participate by providing ramping services and/or voltage control, as well as by alleviating transmission congestion. This research focuses on contributing to modeling and optimization approaches for scheduling the operation of these sources of flexibility in a certain look-ahead horizon, ensuring a state of the art level of modeling accuracy, with full inclusion of voltage control considerations which do not exist in current DC-OPF modeling approaches. Also, by including reactive power flows, the network congestion model proposed is above par compared to the current state-of-the-art for look-ahead dispatch literature. Nevertheless, the model is further expanded by including a thermal model for transmission lines, which allows for the implementation of dynamic line ratings in look-ahead economic dispatch. The benefits from these augmented modeling capabilities are documented and compared with current operating practices. Once an AC-OPF look-ahead optimization problem has been established, and the corresponding components have been modeled, further contributions are made in the area of remedial action schemes. The developed formulations allow for the identification of appropriate corrective actions that will restore feasibility in infeasible cases. Finally, a combination of contingency filtering and contingency analysis approaches is developed, to allow for fast identification and analysis of critical outages in the transmission system. The filtering approach is based on a basic Taylor expansion of network power flow equations as well as a new formulation of margin indices that directly quantify the proximity to constraint violation in the post-outage system state. The analysis approach is based on low-rank modifications of the Jacobian matrix of network equations, to produce good estimates of post-outage operating states and map the effect on the system’s operating constraints. Compared to current state of the art, advances are made both in the speed and the accuracy of the analysis, since the proposed filtering and analysis methods are fully unbalanced. The need for unbalanced security analysis is discussed and justified. Through the contributions made in this research, a roadmap to increase flexibility in power system operations is developed. Namely, an enhanced modeling capability allows for integration of additional sources of flexibility and voltage control and a highly accurate security analysis and remedial actions formulation allows for improved response to unforeseen critical outages and rapid generation changes.
8

Influência do ângulo entre trajetórias lineares no tempo de execução de blocos em usinagem CNC de superfícies / Influence of the angle between linear interpolations in the execution time of a block in CNC machining of surfaces

Moreira, Flávio Camarinho 25 June 2010 (has links)
O presente trabalho trata do desenvolvimento e análise de uma ferramenta de auxílio à otimização de programas CN com relação aos parâmetros tecnológicos planejados. Os atuais módulos de otimização presentes em sistemas CAM não levam em consideração variáveis relativas ao desempenho da máquina ferramenta e do processo, tais qual a dinâmica e a potência da máquina ferramenta, e a capacidade de processamento do CNC. Tal lacuna de informação pode gerar discrepâncias entre os resultados planejados e a realidade, o que faz com que constantes reajustes do processo baseados na experiência do operador sejam necessários. Nesse trabalho, é proposta e avaliada uma ferramenta de monitoramento de variáveis características da máquina ferramenta, cuja principal função é a previsão do tempo de usinagem na fabricação de superfícies complexas. Uma vantagem adicional do sistema de monitoramento proposto é sua implementação através do próprio controle da máquina ferramenta, em máquinas CNC, caracterizadas como de arquitetura aberta, sem a utilização de sensores externos. / The present work is about development and analysis of a support tool for optimization of NC programs with special regard to planned technological metal cutting parameters. The optimization modules presents in CAM systems do not consider the real performance of the machine-tool. Such an information gap can generate discrepancies between planned results and reality, demanding constant adjustments based on the operator\'s process experience. The present work consists of proposing and evaluating of a monitoring tool of the machine characteristic variables, whose the main function is to predict the machining time in the manufacturing of complex surfaces. As an additional advantage, the monitoring is carried through the machine-tool control, in open-CNC machines, without the use of external sensors.
9

Real-time operational response methodology for reducing failure impacts in water distribution systems

Mahmoud, Herman Abdulqadir Mahmoud January 2018 (has links)
Interruption to water services and low water pressure conditions are commonly observed problems in water distribution systems (WDSs). Of particular concern are the unplanned events, such as pipe bursts. The current regulation in the UK requires water utilities to provide reliable water service to consumers resulting in as little as possible interruptions and of as short possible duration. All this pushes water utilities toward developing and using smarter responses to these events, based on advanced tools and solutions. All with the aim to change network management style from reactive to a proactive, and reduce water losses, optimize energy use and provide better services for consumers. This thesis presents a novel methodology for efficient and effective operational, short time response to an unplanned failure event (such as pipe burst) in a WDS. The proposed automated, near real-time operational response methodology consists of isolating the failure event followed by the recovery of the affected system area by restoring the flows and pressures to normal conditions. The isolation is typically achieved by manipulating the relevant on/off valves that are located closely to the event location. The recovery involves selecting an optimal combination of suitable operational network interventions. These are selected from a number of possible options with the aim to reduce the negative impact of the failure over a pre-specified time horizon. The intervention options considered here include isolation valve manipulations, changing the pressure reducing valve’s (PRV) outlet pressure and installation and use of temporary overland bypasses from a nearby hydrant(s) in an adjacent, unaffected part of the network. The optimal mix of interventions is identified by using a multi-objective optimization approach driven by the minimization of the negative impact on the consumers and the minimization of the corresponding number of operational interventions (which acts as a surrogate for operational costs). The negative impact of a failure event was quantified here as a volume of water undelivered to consumers and was estimated by using a newly developed pressure-driven model (PDM) based hydraulic solver. The PDM based hydraulic solver was validated on a number of benchmark and real-life networks under different flow conditions. The results obtained clearly demonstrate its advantages when compared to a number of existing methods. The key advantages include the simplicity of its implementation and the ability to predict network pressures and flows in a consistently accurate, numerically stable and computationally efficient manner under both pressure-deficient and normal-flow conditions and in both steady-state and extended period simulations. The new real-time operational response methodology was applied to a real world water distribution network of D-Town. The results obtained demonstrate the effectiveness of the proposed methodology in identifying the Pareto optimal network type intervention strategies that could be ultimately presented to the control room operator for making a suitable decision in near real-time.
10

Influência do ângulo entre trajetórias lineares no tempo de execução de blocos em usinagem CNC de superfícies / Influence of the angle between linear interpolations in the execution time of a block in CNC machining of surfaces

Flávio Camarinho Moreira 25 June 2010 (has links)
O presente trabalho trata do desenvolvimento e análise de uma ferramenta de auxílio à otimização de programas CN com relação aos parâmetros tecnológicos planejados. Os atuais módulos de otimização presentes em sistemas CAM não levam em consideração variáveis relativas ao desempenho da máquina ferramenta e do processo, tais qual a dinâmica e a potência da máquina ferramenta, e a capacidade de processamento do CNC. Tal lacuna de informação pode gerar discrepâncias entre os resultados planejados e a realidade, o que faz com que constantes reajustes do processo baseados na experiência do operador sejam necessários. Nesse trabalho, é proposta e avaliada uma ferramenta de monitoramento de variáveis características da máquina ferramenta, cuja principal função é a previsão do tempo de usinagem na fabricação de superfícies complexas. Uma vantagem adicional do sistema de monitoramento proposto é sua implementação através do próprio controle da máquina ferramenta, em máquinas CNC, caracterizadas como de arquitetura aberta, sem a utilização de sensores externos. / The present work is about development and analysis of a support tool for optimization of NC programs with special regard to planned technological metal cutting parameters. The optimization modules presents in CAM systems do not consider the real performance of the machine-tool. Such an information gap can generate discrepancies between planned results and reality, demanding constant adjustments based on the operator\'s process experience. The present work consists of proposing and evaluating of a monitoring tool of the machine characteristic variables, whose the main function is to predict the machining time in the manufacturing of complex surfaces. As an additional advantage, the monitoring is carried through the machine-tool control, in open-CNC machines, without the use of external sensors.

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