O problema de dimensionamento de lotes, objeto desse estudo, considera um ambiente composto por múltiplas plantas independentes, múltiplos itens e múltiplos períodos. O ambiente de produção tem capacidade limitada e as plantas podem produzir os mesmos itens. Cada planta tem uma demanda própria e é permitida a transferência de lotes entre as plantas, o que envolve um certo custo. Este problema tem como caso particular o de dimensionamento de lotes com máquinas paralelas. O objetivo desta dissertação é propor uma heurística baseada na meta-heurística GRASP (Greedy Randomized Adaptive Search Procedures). Além disso, uma estratégia path relinking foi incorporada ao GRASP como uma fase de melhoria do algoritmo. Para verificar a eficiência da heurística proposta, os seus resultados são comparados aos da literatura tanto no caso de máquinas paralelas quanto no de múltiplas plantas. Como resultado, o problema de múltiplas plantas obteve melhores resultados quando comparado aos da heurística da literatura. Com relação ao problema de máquinas paralelas, a heurística proposta se mostrou competitiva / The lot sizing problem, which is the aim of this study, considers an environment consisting of multiple independent plants, multiple items and multiple periods. The production environment has limited capacity and the plants can produce the same items. Each plant has its own demand and the lot transfers between the plants are permitted, which involves a certain cost. This problem has as a particular case the parallel machines lot sizing problem. The objective of this dissertation is to propose a heuristic based on the GRASP (Greedy Randomized Adaptive Search Procedures). Furthermore, a path relinking phase is embedded in the GRASP to obtain better performance. To verify the efficiency of the proposed heuristic, its results were compared with the literature as for the multi-plant as for parallel machines problem. Computational tests showed that the proposed heuristic performed better than other literature heuristic concerning the multiplant problem. Concerning the parallel machines, the heuristic is competitive

O problema de dimensionamento de lotes, objeto desse estudo, considera um ambiente composto por múltiplas plantas independentes, múltiplos itens e múltiplos períodos. O ambiente de produção tem capacidade limitada e as plantas podem produzir os mesmos itens. Cada planta tem uma demanda própria e é permitida a transferência de lotes entre as plantas, o que envolve um certo custo. Este problema tem como caso particular o de dimensionamento de lotes com máquinas paralelas. O objetivo desta dissertação é propor uma heurística baseada na meta-heurística GRASP (Greedy Randomized Adaptive Search Procedures). Além disso, uma estratégia path relinking foi incorporada ao GRASP como uma fase de melhoria do algoritmo. Para verificar a eficiência da heurística proposta, os seus resultados são comparados aos da literatura tanto no caso de máquinas paralelas quanto no de múltiplas plantas. Como resultado, o problema de múltiplas plantas obteve melhores resultados quando comparado aos da heurística da literatura. Com relação ao problema de máquinas paralelas, a heurística proposta se mostrou competitiva / The lot sizing problem, which is the aim of this study, considers an environment consisting of multiple independent plants, multiple items and multiple periods. The production environment has limited capacity and the plants can produce the same items. Each plant has its own demand and the lot transfers between the plants are permitted, which involves a certain cost. This problem has as a particular case the parallel machines lot sizing problem. The objective of this dissertation is to propose a heuristic based on the GRASP (Greedy Randomized Adaptive Search Procedures). Furthermore, a path relinking phase is embedded in the GRASP to obtain better performance. To verify the efficiency of the proposed heuristic, its results were compared with the literature as for the multi-plant as for parallel machines problem. Computational tests showed that the proposed heuristic performed better than other literature heuristic concerning the multiplant problem. Concerning the parallel machines, the heuristic is competitive

本論文針對多廠區訂單分配（Multi-plant order allocation）問題進行探討，此問題模式下企業擁有多間製造不同產品之工廠，且生產成本、產能、運送成本等也各自不同，因此這些因素都必須納入訂單分配時的考量。研究中同時考量三個目標：製造成本、配送前置時間和工廠平均產能利用率之均衡性，利用層級分析法（AHP）將三者進行結合，以達到多目標規劃。除了提出此模型架構外，並以基因演算法（Genetic Algorithm）結合層級分析法進行問題的求解，以達到最佳的分配方式，而為了加強求解的品質與效率，利用禁忌搜尋法（Tabu Search）來改善演化過程中，對於產生不可行解的處理方式。在研究最後，將計算結果與過去研究成果作比較，顯示採用基因演算法混合禁忌搜尋法，在求解多廠區訂單分配問題時，可以得到較佳的結果。

This thesis consists of four self-contained essays. The common theme of the essays is the behavior of multi-plant firms. An underlying idea in all four of them is that firms possess intangible assets such as management skills and organizational expertise, technological knowledge, marketing know-how and better access to finance capital or natural resources. These assets are typically specific to the respective firm. Due to market imperfections and failures, firms tend to internalize the advantages of firm-specific assets and exploit them themselves rather than sell or lease them to other firms. For instance, intangible assets are often joint inputs in the sense that knowledge developed by one unit can be transferred to another unit within the same firm at a low cost and without diminishing the amount of knowledge available to the first unit. Furthermore, the assets are typically only partly appropriable by their owner, and the market transactions of the assets are hampered due to information asymmetries between a potential buyer and seller. The literature on multinational firms emphasizes the role of intangible firm-specific assets in creating ownership advantages that, together with location and internalization advantages, explain the pattern of foreign direct investments. The essays in this thesis are based on the view that the ownership advantages created by firm-specific assets are the "raison d'etre" of large multi-plant firms. The existence of such assets is assumed to create multi-plant economies of scale and give incentives to make better use of capacity or overheads to gain advantage in size, economies of interdependent activities, integration and/or diversification. Rather than studying the international aspects of firms with intangible assets, the first three essays empirically explore different aspects of multi-plant firm behavior in domestic markets. This analysis has been made possible by the access to unique plant-level data on the thirty largest multinational manufacturing corporations in Sweden. The sample corporations play an important role in the Swedish economy. For instance, the thirty corporations account for about 70 percent of aggregate industrial R&D in 1999. This should be compared with their share of total manufacturing employment, which was about 30 percent during the period of study. The first essay examines the sources of productivity growth within multi-plant firms and particularly emphasizes the role of external restructuring and ownership changes in explaining why multi-plant firms may sustain higher productivity growth as compared to single-plant firms. The second and the third essay explore the idea that large multi-plant corporations exploit their ownership advantages when acquiring partial- and full-firm assets. The second essay analyzes whether technological intangible assets may explain transfers of productive capacity from acquiring corporations to their target. The third essay explores the idea that multi-plant corporations search for targets matching their firm-specific organizational capabilities when acquiring corporate assets. Uncertainty about the matching outcome explains why some acquisitions end in divestitures. However, the likelihood of a "good" match is expected to increase in the buyer's organizational capabilities. The fourth essay, coauthored with Karolina Ekholm, extends the analysis to encompass the international aspects of multinational firms. In this essay, we develop a theoretical model analyzing the localization decisions of multi-plant firms beyond the national borders. More specifically, we develop a two-country model where firms can choose to separate their innovative activities generating an intangible asset from the production of the final good. In our model, there are two agglomeration forces: knowledge spillovers associated with R&D and backward and forward linkages associated with high-tech production. We analyze how the interplay of these forces affects the localization decisions of the firms. / Diss. Stockholm : Handelshögsk., 2003