This thesis contains an account of several modifications to two algorithms for unconstrained optimization, both of which are due to Gill and Murray. Chapter One contains a brief survey of unconstrained optimization and contains also some results which are used subsequently. Chapter Two contains an account of some work on iterative procedures for the solution of operator equations in Banach spaces due to Wolfe (1978a) in which it is suggested that it may be possible, in certain circumstances, to use high-order iterative procedures rather than Newton's method, thereby obtaining computational advantages. In Chapter Three the Newton-type algorithm of Gill and Murray (1974) is described and the ideas contained in Chapter Two are used to construct some modifications of this algorithm. Chapter Four contains some algorithms for the numerical estimation of both full and b and-type Hessian matrices. These algorithms may be used in conjunction with the optimization algorithms which are described in Chapters Three and Five. In Chapter Five the least-squares algorithm of Gill and Murray (1976) is described and the ideas contained in Chapter Two are used to construct some modifications of this algorithm. Chapter Six contains the computational results which were obtained by using the algorithms which are described in Chapters Three, Four and Five to solve the test problems which are listed in Appendices One and Two.

This thesis contains a description of algorithm, MW, for bounding the global minimizers and globally minimum value of a twice continuously differentiable function f :Rn → R1 R1 in a compact sub-interval of Rn. The algorithm MW is similar to the algorithm of Hansen (Han-80a] in that interval arithmetic is used together with certain of Hansen's ideas, but is different from Hansen's algorithm in that MW bounds the Kuhn Tucker points corresponding to the global minimizers of f in the given sab-interval. The Kuhn Tucker points are bounded with prescribed precision by using either of the algorithms KMSW [SheW-85c] or MAP [SheW-85b]. Numerical results which are obtained from Triplex [BaCM-82a] [MorC-83a] implementations of H and MW axe presented.

In this study, we have aimed to optimize patient flow in emergency departments while minimizing associated costs. In order to be able to compare the effect of any changes, we developed a simulation model for an emergency department using Queuing theory, and regarding the optimization we utilized Genetic Algorithm to find the best change. Basically, we have designed a Discrete Event based, multi-class, multi-server queuing network as we have considered the emergency department a set of stages associated with a queue of patients waiting to be served. Each stage has multiple service providers such as Nurses, Doctors or other staff. We also classified patients passing through the stages, according to their acuity level and personal characteristics. Then, we defined a function as a measure of the ED performance in respect to the calculated wait times and the cost. Finally, we developed a customized genetic algorithm to find the best performance which reflects the best allocation of service providers into multiple stages of the emergency department.

Master of Agribusiness / Department of Agricultural Economics / Keith Harris / The growing number of participants in the grain market shows just how globalized this sector is in Brazil nowadays. It is difficult to distinguish between mergers and acquisitions of local companies and that of investment funds, which are actively engaged in acquiring a part or even the totality of Brazilian companies. For instance, the soybean crushing company “XYZ” that acquired some assets such as crushing plants in the state of Mato Grosso, located on the center-west region of Brazil and access to two port terminals to export the byproducts. This thesis contains data from January of 2014 to September of 2017, which includes prices of soybean and by products, freight rates, basis at the ports and operational costs. This information is from different sources including government and private agencies and Thomson Reuters Eikon software. This information was used to build a model in Microsoft Excel and by using the Risk Solver Platform, a statistic calculator tool and to find a solution to improve “XYZ” profitability. The results of the model suggest changes in the origination of grains, a reduction of the volume in some locations and increasing the volume originated in other locations. After running two different scenarios, “XYZ” profit increased by 3.81 million of Brazilian Reais.

No description available.

Optimization methodologies are particularly relevant nowadays due to the ever-increasing power of computers and the enhancement of mathematical models to better capture reality. These computational methods are used in many different fields and some of them, such as metaheuristics, have often been found helpful and efficient for the resolution of practical applications where finding optimal solutions is not straightforward. Many practical applications are multi-objective optimization problems: there is more than one objective to optimize and the solutions found represent trade-offs between the competing objectives. In the last couple of decades, several metaheuristics approaches have been developed and applied to practical problems and multi-objective versions of the main single-objective approaches were created. The Alliance Algorithm (AA) is a recently developed single-objective optimization algorithm based on the metaphorical idea that several tribes, with certain skills and resource needs, try to conquer an environment for their survival and try to ally together to improve the likelihood of conquest. The AA method has yielded reasonable results in several fields to which it has been applied, thus the development in this thesis of a multi-objective variant to handle a wider range of problems is a natural extension. The first challenge in the development of the Multi-objective Alliance Algorithm (MOAA) was acquiring an understanding of the modifications needed for this generalization. The initial version was followed by other versions with the aim of improving MOAA performance to enable its use in solving real-world problems: the most relevant variations, which led to the final version of the approach, have been presented. The second major contribution in this research was the development and combination of features or the appropriate modification of methodologies from the literature to fit within the MOAA and enhance its potential and performance. An analysis of the features in the final version of the algorithm was performed to better understand and verify their behavior and relevance within the algorithm. The third contribution was the testing of the algorithm on a test-bed of problems. The results were compared with those obtained using well-known baseline algorithms. Moreover, the last version of the MOAA was also applied to a number of real-world problems and the results, compared against those given by baseline approaches, are discussed. Overall, the results have shown that the MOAA is a competitive approach which can be used `out-of-the-box' on problems with different mathematical characteristics and in a wide range of applications. Finally, a summary of the objectives achieved, the current status of the research and the work that can be done in future to further improve the performance of the algorithm is provided.

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Dissertation submitted in fulfilment of the requirements for the degree Master of Technology: Mechanical Engineering in the Faculty of Engineering at the Cape Peninsula University of Technology 2014 / The research described in this dissertation investigates the feasibility of casting inlet valves for an internal combustion engine using Ti6Al4V alloy. The engine valves operate in an extreme environment under high thermal cycles – this requires a material that can withstand such exposures. Ti6Al4V is the most common titanium alloy with high temperature creep and fatigue resistant behaviour, however, it is not all positive. Ti6Al4V alloy also yields many difficulties with respect to processing especially when the material is cast. It is therefore important to gain a thorough understanding of the pouring and solidification characteristics of this material. The main focus of this work was to investigate and optimise feeding and geometrical parameters to produce valves that are free from defects, especially porosity. An in depth analyses of the parameters that influenced the casting quality was performed, and it was found that casting orientation, inlet feeder geometry, initial and boundary conditions all played a vital role in the final results. These parameters were individually investigated by performing detailed numerical simulations using leading simulation software for each of these cases. For each case, a minimum of ten simulations was performed to accurately determine the effect of the alteration on casting soundness and quality. Furthermore, the relationships (if any) were observed and used in subsequent optimised simulations of an entire investment casting tree. The change of geometric orientation and inlet feeder diameter and angle showed distinct relationships with occurrence of porosity. On the other hand, alteration in the pouring parameters, such as temperature and time, had negligible effect on occurrence or position of porosity in the valve. It was found that investigating individual parameters of simple geometry and then utilising these best-fit results in complex geometry yielded beneficial results that would otherwise not be attainable.

Made available in DSpace on 2014-06-12T15:56:01Z (GMT). No. of bitstreams: 2 arquivo2386_1.pdf: 2486508 bytes, checksum: 840656846098d64ece51b53216ff079b (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2009 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Marcelo Xavier Natário Teixeira, João; Kelner, Judith. Finding an adequate escape pod to real time augmented reality applications. 2009. Dissertação (Mestrado). Programa de Pós-Graduação em Ciência da Computação, Universidade Federal de Pernambuco, Recife, 2009.

Made available in DSpace on 2014-10-09T12:38:50Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:59:42Z (GMT). No. of bitstreams: 1 02812.pdf: 5708328 bytes, checksum: a606b573bae516661b8d82305470dbda (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP