In this thesis, we consider a capacity allocation problem in flexible manufacturing systems. We assume limited time and tool magazine capacities on the Computer Numerically Controlled (CNC) machines. We have a set of operations that have to be assigned to the machines and each operation requires a set of tools to be processed. Our problem is to allocate the available capacity of the CNC machines to operations and their required tools. We consider two problems in this study: maximizing the total weight of operations where there are a limited number of tools of each type available and maximizing total weight minus total tooling cost where the tools can be used or purchased at a cost. We model the problems as Integer Linear Programs and show that they are NP-hard in the strong sense. For the total weight problem, we propose upper bounds, branch and bound algorithm for exact solutions and several heuristics for approximate solutions. For the bicriteria problem, we use Lagrangean relaxation technique to obtain lower and upper bounds. Our computational results have revealed that all solution approaches give satisfactory results in reasonable times.

Foi realizado um estudo quase experimental, com processo periódico de medida, entre 1986 e 1992, baseado em variáveis e indicadores referentes à produção de serviços de saúde ambulatoriais e hospitalares, no nível de saúde da população e no financiamento dos serviços. A população de intervenção foi a cidade de Londrina, através de seu sistema de serviços de saúde baseado na assistência primária. As populações de comparação foram as do Estado do Paraná e a do Brasil, que não foram objeto de ações semelhantes em igual período. O estudo teve o objetivo principal de avaliar as relações entre o aumento da capacidade operativa dos serviços de saúde ao nível ambulatorial e a demanda de serviços de saúde ao nível hospitalar. Constatou-se no estudo a redução das freqüências de internação hospitalar da população residente em Londrina, na vigência de uma política de saúde local que priorizou a extensão de cobertura dos serviços de saúde ao nível primário, e obteve como conseqüência o aumento das freqüências absolutas de consultas médicas e de atendimentos básicos; o aumento das razões de consultas médicas por habitante; o aumento das razões de consultas médicas por internação, e a melhora dos indicadores de saúde. / A quasi-experimental study design was carried out from 1986 to 1992, involving repeated measurements on population health variables and indicators related with: outpatient and hospital health services delivery; population health level and health services financing throughout the observational period. The unit under intervention was Londrina City, compared to the state of Parana and the Country - Brazil, which did not undergo analogous health services modifications. The main objective of the study was to evaluate the relationship amongst operational health service increased capacity at the primary level, and the demands for hospital admissions. The study concluded that the general hospital admission frequencies and rates were lowred during the time when the changing local health policy became effective, maintaining a time downward trend with the primary health services extension of coverage. Other health services indexes that showed improving profiles during the same period were: general population health indicators; medical consultations; basic non-medical attendances, and ratio of medicai visits per inhabitants-vear.

Foi realizado um estudo quase experimental, com processo periódico de medida, entre 1986 e 1992, baseado em variáveis e indicadores referentes à produção de serviços de saúde ambulatoriais e hospitalares, no nível de saúde da população e no financiamento dos serviços. A população de intervenção foi a cidade de Londrina, através de seu sistema de serviços de saúde baseado na assistência primária. As populações de comparação foram as do Estado do Paraná e a do Brasil, que não foram objeto de ações semelhantes em igual período. O estudo teve o objetivo principal de avaliar as relações entre o aumento da capacidade operativa dos serviços de saúde ao nível ambulatorial e a demanda de serviços de saúde ao nível hospitalar. Constatou-se no estudo a redução das freqüências de internação hospitalar da população residente em Londrina, na vigência de uma política de saúde local que priorizou a extensão de cobertura dos serviços de saúde ao nível primário, e obteve como conseqüência o aumento das freqüências absolutas de consultas médicas e de atendimentos básicos; o aumento das razões de consultas médicas por habitante; o aumento das razões de consultas médicas por internação, e a melhora dos indicadores de saúde. / A quasi-experimental study design was carried out from 1986 to 1992, involving repeated measurements on population health variables and indicators related with: outpatient and hospital health services delivery; population health level and health services financing throughout the observational period. The unit under intervention was Londrina City, compared to the state of Parana and the Country - Brazil, which did not undergo analogous health services modifications. The main objective of the study was to evaluate the relationship amongst operational health service increased capacity at the primary level, and the demands for hospital admissions. The study concluded that the general hospital admission frequencies and rates were lowred during the time when the changing local health policy became effective, maintaining a time downward trend with the primary health services extension of coverage. Other health services indexes that showed improving profiles during the same period were: general population health indicators; medical consultations; basic non-medical attendances, and ratio of medicai visits per inhabitants-vear.

The ambitious governmental policies, particularly in Europe, in pursuit of established energy targets require an increase in distributed generation. As a result, photovoltaic (PV) technologies have emerged, predominantly at residential Low Voltage (LV) feeders. However, PV rich LV feeders are highly likely to pose technical challenges such as significant voltage rise and thermal overloading. This inevitably limits the volume of PV systems that can be hosted on LV feeders. Therefore, the deployment of solutions that can enable feeders to accommodate greater volumes of PV systems without having any technical issues is crucial. This thesis, consequently, thoroughly investigates one of the potential solutions: transforming the radial operation of LV feeders into ring operation. European-style LV feeders are typically operated in a radial fashion and yet are designed to be reconfigurable with neighbouring feeders. It is, therefore, essential to identify the best pairing option (of PV rich LV feeders) in a practical and straightforward manner due to the large number of existing LV feeders in a given Distribution Network Operator (DNO) area. This thesis proposes a generic innovative methodology to enable DNOs to straightforwardly identify the best pairing feeder; a decision-making tool to facilitate the rapid uptake of PV systems. To accomplish this goal, an impact assessment of a set of real residential LV feeders is carried out to identify the first technical issue/constraint that limits their hosting capacity. Next, regression analyses are carried out to gain an understanding of the relation between this first occurrence of technical issue/constraint and the corresponding level of PV penetration. The most practical and adequately accurate metric needs to be chosen. Feeders are then classified based on the range of metrics to cover all possible pairing cases. Finally, the ring operation of feeders in each class is analysed and hosting capacities are compared to those of radial ones. This process creates a practical matrix from which DNOs can easily identify the best pairing feeders. DNOs are likely to be hesitant to adopt permanent ring operation as it is not typically adopted in traditional LV feeders. Therefore, the switch located between feeders can be operated over time (i.e., dynamic ring operation) to reduce the duration for which ring operation is in place. It is, however, challenging to identify the most favourable control strategy. This thesis proposes different strategies for dynamic ring operation. Note that the most preferable control strategy is that which preserves the benefits of permanent ring operation with the minimum duration of ring operation and minimum number of switching. To achieve this, four different control strategies are explored-using different control cycles and considering hosting capacity, duration and switching. The best control strategy is found to be able to increase hosting capacity as permanent ring operation, reduce switching actions and minimise duration of ring operation compared to other proposed strategies and, crucially, operate ring operation only when it is truly needed. Finally, this thesis investigates the use of ring operation with an LV on-load tap changer (OLTC) as this is recently available voltage control technologies and is increasingly drawing the attention of DNOs. Two approaches are investigated to increase hosting capacity and limit ring operations: the use of the switch and OLTC are controlled separately using local measurements (i.e., localised) and their simultaneous control at the LV transformer level (i.e., centralised). The latter gives the priority to the OLTC to minimise the duration of the ring operation. The assessments are extended to cover an integrated medium and low voltage network to obtain more realistic results. The results show that centralised approach provides better performance considering hosting capacity, the number of switching/tap actions and the duration of ring operation.