Geographic Information System (GIS) address-matching combined with other GIS processing offers new analytical opportunities in the area of transportation planning and analysis. Address-matching, an automated method for generating geographically-referenced (geocoded) point locations on a map from common tabular databases, can facilitate transportation analysis by providing a planning tool based on individual rather than aggregated spatial distributions more common to transportation issues.

This research focuses on large-scale manufacturing systems having a number of stations with multiple tools and product types with different and deterministic processing steps. The objective is to determine the production quantities of multiple products and the tool requirements of each station that maximizes net profit while satisfying strategic constraints such as cycle times, required throughputs, and investment. The formulation of the problem, named OptiProfit, is a mixed-integer nonlinear programming (MINLP) with the stochastic issues addressed by mean-value analysis (MVA) and queuing network models. Observing that OptiProfit is an NP-complete, nonconvex, and nonmonotonic problem, the research develops a heuristic method, Differential Coefficient Based Search (DCBS). It also performs an upper-bound analysis and a performance comparison with six variations of Greedy Ascent Procedure (GAP) heuristics and Modified Simulated Annealing (MSA) in a number of randomized cases. An example problem based on a semiconductor manufacturing minifab is modeled as an OptiProfit problem and numerically analyzed. The proposed methodology provides a very good quality solution for the high-level design and operation of manufacturing facilities.

This thesis describes preliminary research on the application of Markov Decision Processes (MDPs) to the optimisation of mine scheduling in an uncertain environment. The MDP framework is a novel approach to scheduling in a mining operation and option valuation. The task of scheduling in mining operations is dependent on the availability of models that permit the representation of some of the key stochastic properties of the environment, such as grade and price uncertainty. The tools used to model these processes are respectively sequential Gaussian simulation and Geometric Brownian motion. Three cases of increasing size are used to illustrate the results of the model and demonstrate its suitability to mine scheduling and option valuation. The computational efficiencies of solving an MDP formulation by Policy Iteration and Value Iteration are compared. The impact of the discount rate on the optimal policy is assessed. To determine the value of one or several options, an optimal policy without options is generated and valued. Then, the exercise is repeated with the relevant options to value (e.g., production rate, cut-off grade and time of mine closure). By comparing the values obtained in both cases, the financial benefit of having operational flexibility is determined, thus yielding the option value. A full size case study is conducted to validate the applicability of MDPs to real mining projects.

In this thesis, we study two stochastic vehicle routing problems. In the first part, we investigate a routing problem where the distributor wants to construct a set of delivery routes each day to serve a set of geographically dispersed customers, but wants to send the same driver to the same set of customers as much as possible due to business requirements. The stochastic nature of customer demands and the existence of hard delivery time windows make this fixed routes problem much harder. We introduce a new recourse policy based on limited vehicle sharing and develop heuristic approaches for constructing fixed routes respecting the new policy for large real-life instances. Among the key contributions is the introduction of sampling-based techniques to handle the feasibility issues arising from hard delivery windows. An extensive computational study based on real-life data demonstrates the efficacy of the proposed fixed routing system and route construction techniques. In the second part, we investigate the new policy in an abstract setting to understand its properties. We characterize the optimal traditional fixed routes solution in terms of total expected cost for simple instances of the problem. Next we present a series of results for the new policy. For example, we show that operational feasibility of a set of fixed routes can be checked in polynomial time, but identifying the optimal use of fixed routes is NP-complete. In the final part, we focus on a dynamic and stochastic routing problem, which arises when there are service level agreements in place between a distributor and its customers. Specifically, the distributor has to serve customer orders within two days after the order is received, but has the flexibility to choose the actual delivery day. However, future customer orders are unknown and are revealed dynamically through time. We develop heuristic and optimal policies for simple instances of the problem that use the stochastic information about future orders. We empirically compare the performance of the various policies with the performance of policies that do not use future information and with an offline optimal policy which has perfect information about future orders.

In this modern era, energy is a key element required for sustainable development and prosperity of a society. Pakistan is an energy deficient country facing problems due to the shortage of over 4000 MW of electricity. The national energy sector is heavily dependent on imported fossil-fuel resources. The energy crisis is negatively affecting all economic and business activities, and it is widely recognized as a severe obstacle to growth and poverty reduction in the country. Establishment of wind farms can help to overcome the energy crisis. In this research, a national level wind energy roadmap is developed through scenario planning. Multiple future scenarios are developed using the fuzzy cognitive maps (FCM) approach. This research has extended technology roadmapping through FCM-based scenario analysis. Building scenarios with FCM is a very new approach, and for the first time FCM-based scenarios are developed for the wind energy sector of Pakistan. Based on these multiple scenarios, a technology roadmap has been developed. This research approach is applied to the wind energy sector of Pakistan as a case study. This approach has been used to establish objectives and national targets of the roadmap. Then in a systematic way, critical roadmap barriers are identified against each scenario, and appropriate action items have been proposed to overcome barriers and promote deployment of wind energy projects in Pakistan. The objectives and targets of the roadmap have been translated into action items. The technology roadmap has four layers: strategic objectives, targets, barriers, and action items. Expert panels have been utilized to develop scenarios and technology roadmaps. Validation of this research is also carried out using experts. This new approach has helped to develop a robust roadmap and enabled anticipation of a wide range of possible future outcomes. This research fills an important gap by combining scenario planning and technology roadmapping techniques in future studies, and it has enhanced flexibility of the developed roadmap. Moreover, for the first time multiple and plausible FCM-based scenarios are developed, which combine the benefits of both qualitative and quantitative analysis. Moreover, the technology roadmap for the wind energy sector of Pakistan is developed with a comprehensive study of practical obstacles and barriers towards deployment of wind energy technology. The research findings suggest that policy, financial, economic, lack of competition with conventional power plants, and technical are the most critical barriers towards deployment of wind energy projects in the country. Appropriate action items required to overcome the roadmap barriers against each scenario are also proposed in the developed roadmap. The experts also assigned responsibilities for the key roadmap action items to the major stakeholders.

No description available.

Braess' paradox is a counter-intuitive phenomenon which can occur in congesting networks. It refers to those cases where the introduction of a new link in the network results in the total travel time on the network increasing. The dissertation starts by introducing the traffic assignment problem and the concept of equilibrium in traffic assignment. The concept of equilibrium is based on Wardrop's first principle that all travellers will attempt to minimize their own travel time regardless of the effect on others. A literature review includes details of a number of papers that have been published investigating theoretical aspects of the paradox. There is also a brief description of Game Theory and the Nash Equilibrium. It has been shown that the equilibrium assignment is an example of Nash Equilibrium. The majority of work that has been published deals with networks where the delay functions that are used to compute the travel times on the links of the network do not include explicit representation of the capacity of the links. In this dissertation a network that is similar in form to the one first presented by Braess was constructed with the difference being that the well-known BPR function was used in the delay functions. This network was used to show that a number of findings that had been presented previously using simpler functions also applied to this network. It was shown that when it occurs, Braess' paradox only occurs over a range of values at relatively low levels of congestion. Real-world networks were then investigated and it was found that similar results occurred to those found in the simpler test networks that are often used in discussions of the paradox. Two methodologies of eliminating the paradox were investigated and the results are presented. / Decision Sciences / M.Sc.

Braess' paradox is a counter-intuitive phenomenon which can occur in congesting networks. It refers to those cases where the introduction of a new link in the network results in the total travel time on the network increasing. The dissertation starts by introducing the traffic assignment problem and the concept of equilibrium in traffic assignment. The concept of equilibrium is based on Wardrop's first principle that all travellers will attempt to minimize their own travel time regardless of the effect on others. A literature review includes details of a number of papers that have been published investigating theoretical aspects of the paradox. There is also a brief description of Game Theory and the Nash Equilibrium. It has been shown that the equilibrium assignment is an example of Nash Equilibrium. The majority of work that has been published deals with networks where the delay functions that are used to compute the travel times on the links of the network do not include explicit representation of the capacity of the links. In this dissertation a network that is similar in form to the one first presented by Braess was constructed with the difference being that the well-known BPR function was used in the delay functions. This network was used to show that a number of findings that had been presented previously using simpler functions also applied to this network. It was shown that when it occurs, Braess' paradox only occurs over a range of values at relatively low levels of congestion. Real-world networks were then investigated and it was found that similar results occurred to those found in the simpler test networks that are often used in discussions of the paradox. Two methodologies of eliminating the paradox were investigated and the results are presented. / Decision Sciences / M.Sc.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O problema de seqüenciamento da produção vem sendo estudado desde o início da década de 50 do século passado e tem recebido nestes últimos cinqüenta anos uma considerável atenção de pesquisadores de todo o mundo. Como resultado atualmente encontra-se disponível uma gama de métodos de otimização e aproximação voltados para solução deste tipo de problema, sendo que a aplicação destes métodos mostra-se limitada à solução de problemas padrões de seqüenciamento, os quais consideram um conjunto de simplificações que os distanciam dos problemas ocorrentes nos ambientes reais de produção. Nesta dissertação o problema de seqüenciamento da produção sob análise trata-se especificamente do problema ocorrente nas micro e pequenas empresas do setor de confecções situadas no município de Nova Friburgo, onde foi constatado que quase não há um planejamento prévio da produção e quando o mesmo ocorre é feito com base somente em informações empíricas sem a aplicação de nenhuma metodologia e sem o auxílio de qualquer ferramenta computacional. Tal falta de planejamento resulta em um mau aproveitamento dos recursos de produção e impede que a empresa possa produzir em maior escala, o que se mostra necessário já que usualmente a demanda supera a capacidade produtiva da maioria das empresas do setor de confecções, principalmente em se tratando do sub-setor de moda íntima o qual abrange a maioria das empresas do município de Nova Friburgo. Visando melhorar o potencial competitivo destas empresas, esta dissertação se propõe a modelar matematicamente o seu processo de produção e desenvolver uma ferramenta computacional para a programação da produção baseada no método Tabu Search. / The manufacturing scheduling problem has been investigated since the 50s of the past century, and has received in the last 50 years a lot of attention from researchers around the world. As a result of such research efforts a lot of approximation and optimization methods are now available for the solution of such problems. Nonetheless, the application of these methods has been limited to standard problems of scheduling which considers a member of simplifications that do not correspond to the practical situations found in real production sets. In the present dissertation the manufacturing scheduling problem is devoted to real small and companies of productions sector of Nova Friburgo, for which has been observed that there is almost no prior production planning made, and when it is performed it is based only on empirical information without the application of a methodology or the aid of a computational tool. Such lack of planning results in a poor use of the production resources and prevents the company to produce in a larger scale, which is necessary because usually the demand is larger than the production capability of the majority of the companies of productions sector, manly in the sub-sector of underwear which corresponds to the majority of the companies of Nova Friburgo. Seeking to enhance the competitive edge of such companies the present dissertation has the purpose of modeling the production process and develop a computational tool for the production scheduling based on the Tabu Search method.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O problema de seqüenciamento da produção vem sendo estudado desde o início da década de 50 do século passado e tem recebido nestes últimos cinqüenta anos uma considerável atenção de pesquisadores de todo o mundo. Como resultado atualmente encontra-se disponível uma gama de métodos de otimização e aproximação voltados para solução deste tipo de problema, sendo que a aplicação destes métodos mostra-se limitada à solução de problemas padrões de seqüenciamento, os quais consideram um conjunto de simplificações que os distanciam dos problemas ocorrentes nos ambientes reais de produção. Nesta dissertação o problema de seqüenciamento da produção sob análise trata-se especificamente do problema ocorrente nas micro e pequenas empresas do setor de confecções situadas no município de Nova Friburgo, onde foi constatado que quase não há um planejamento prévio da produção e quando o mesmo ocorre é feito com base somente em informações empíricas sem a aplicação de nenhuma metodologia e sem o auxílio de qualquer ferramenta computacional. Tal falta de planejamento resulta em um mau aproveitamento dos recursos de produção e impede que a empresa possa produzir em maior escala, o que se mostra necessário já que usualmente a demanda supera a capacidade produtiva da maioria das empresas do setor de confecções, principalmente em se tratando do sub-setor de moda íntima o qual abrange a maioria das empresas do município de Nova Friburgo. Visando melhorar o potencial competitivo destas empresas, esta dissertação se propõe a modelar matematicamente o seu processo de produção e desenvolver uma ferramenta computacional para a programação da produção baseada no método Tabu Search. / The manufacturing scheduling problem has been investigated since the 50s of the past century, and has received in the last 50 years a lot of attention from researchers around the world. As a result of such research efforts a lot of approximation and optimization methods are now available for the solution of such problems. Nonetheless, the application of these methods has been limited to standard problems of scheduling which considers a member of simplifications that do not correspond to the practical situations found in real production sets. In the present dissertation the manufacturing scheduling problem is devoted to real small and companies of productions sector of Nova Friburgo, for which has been observed that there is almost no prior production planning made, and when it is performed it is based only on empirical information without the application of a methodology or the aid of a computational tool. Such lack of planning results in a poor use of the production resources and prevents the company to produce in a larger scale, which is necessary because usually the demand is larger than the production capability of the majority of the companies of productions sector, manly in the sub-sector of underwear which corresponds to the majority of the companies of Nova Friburgo. Seeking to enhance the competitive edge of such companies the present dissertation has the purpose of modeling the production process and develop a computational tool for the production scheduling based on the Tabu Search method.