Two important areas of decision-making in distribution system design involve facility location and inventory policy determination. Facility location analyzes questions such as how many facilities should be opened, where they should be located, and which customers should be assigned to which DCs. Inventory policy determination involves more tactical decisions such as the order quantities and frequencies at each level or echelon in the network. It is believed that these two decisions can influence each other significantly. Including a multi-echelon inventory policy decision in a location analysis allows a user to capitalize on the strengths that each DC has to offer (e.g., lower labor rates, land costs, etc.). Likewise, when the locations of two facilities are known, a multi-echelon inventory policy can be designed better to incorporate the exact lead times and fixed costs between the facilities at each level of the system. Despite this, the two problems are typically solved independently. This research addresses these problems together and investigates different heuristic methods for solving a combined inventory-location model. We begin by presenting the background and formulation for each problem. These formulations are then combined to show how the two problems can be mathematically formulated together. Rather than solve the problem exactly, two heuristic methods using different philosophies are tested. We apply these heuristic methods to the combined inventory-location problem to determine how much we can improve distribution network design solutions and what type of heuristic methodology is most effective in gaining these improvements. Our results show that the combined inventory-location model is capable of improving on the solutions obtained by a location model with a fixed inventory policy. The improvement based on the data sets tested in this research was approximately $60,000. However, in cases where the inventory costs are a larger portion of the total cost, the improvement made by the inventory-location model increased to over $1,000,000. We also found that our second heuristic method tested provided statistically significant improved results over our first heuristic method. Moreover, the second heuristic method typically ran 67% faster. The improved results, although small in a relative sense (the average improvement was 0.18%), would still represent a large absolute improvement in supply chain costs. As much as $174,000 was saved in the data sets tested for this research. / Master of Science

In this study, we focus on a real life problem that involves a single item which is used in military operations. The items in use fail according to a Poisson process and lead times are deterministic. Four alternative inventory control models are developed. Among these models, a two-echelon system consisting of a depot in the upper and several bases in the lower echelon is operated currently. This system is compared to a single-echelon system that consists of several bases. The comparison reveals the importance of the holding cost incurred for the items intransit between the depot and the base which is ignored in most of the studies in literature. Both the two and single-echelon models are also extended to have repair ability. A continuous-review base-stock policy is used for all models. Exact models are formulated. The results are obtained under various lead time, unit costs and demand parameters. Results of four different settings are compared and the findings are reported.

La distribution de marchandises est un secteur en constant développement et constitue un facteur économique important. Par contre, dans les villes, il contribue notamment aux problèmes de congestion, pollution, bruit et d'autres dérangements à la population des villes. Pour faire face à ces problèmes, une nouvelle discipline est née à la fin du XXe siècle, la " City Logistics ", qui a comme objectifs principaux la réduction de la congestion, la pollution et le bruit occasionné par le transport de marchandises en ville. Dans les dernières années, plusieurs études et expériences se sont développées en toute l'Europe, mais pour l'instant une politique commune en matière de logistique urbaine n'a pas encore été proposée par l'Union Européenne. En Italie, seulement certaines villes de petite taille ont expérimenté des politiques de " city logistics " avec succès, mais sans un lien entre elles. Nous observons que ces expériences utilisent des centres urbains de distribution de marchandises, ce qui peut se traduire en un système de transport à deux ou plus niveaux. Plusieurs études en recherche opérationnelle ont traité des problématiques liées à des systèmes à niveaux multiples pour la distribution de marchandise. Néanmoins, l'optimisation des coûts de transport est en générale réalisé en considérant chaque niveau indépendant des autres, ou en approximant les coûts du transport dans certains niveaux pour simplifier. Un autre problème est le manque d'une unification de la terminologie utilisée dans ces études, qui difficulte la recherche bibliographique. Le but de cette recherche est, d'un coté, proposer des lignes guide d'accion en matière de planification de la distribution urbaine de marchandises, en unifiant certains termes, et d'un autre coté présenter une famille de problèmes d'optimisation de routes des véhicules qui considère les systèmes à niveaux multiples dans son ensemble et pas comme une somme de systèmes indépendants. Dans un premier temps, nous présentons les principales expériences de " city logistics " en Italie, ainsi que des lignes d'action dans la planification des systèmes de distribution urbaine des marchandises qui puissent devenir opérationnels et efficients. Ensuite nous présentons les principales problématiques et limites de l'optimisation de systèmes de transports à niveaux multiples, en unifiant les concepts et la notation. Nous proposons une nouvelle famille de problèmes d'optimisation de routes de véhicules pour des systèmes à niveaux multiples, en détaillant le cas basique : le problème de routes de véhicules à deux niveaux. Nous proposons des modèles mathématiques pour ce problème et des résultats numériques pour illustrer les avantages et les limites de la modélisation de ces systèmes.

With the ongoing globalization and changes in the economic environment, organizations need to be flexible and adaptable towards new situations and opportunities. In a context where firms strategically reach across national borders, firms are encountering differing cultural backgrounds. Multinational corporations (MNCs) are confronted with the question of how to fill executive positions. The need for employees with international expertise arises to reap the advantage of nationality diversity by matching the complexity of the global environment with the right level of board capital. Such firm managers must work in increasingly international contexts and cross-cultural environments. Scholars have regarded diversity as an essential element that helps organizations and their executives to deal with uncertainties arising from globalization. (Koles 2014). The top executives of an organization are regarded as an essential criterion for firm´s success. Top managers have considerable influence over the fate of the organizations they lead. These trends have led to increasing instability in classic employment relationships and show greater diversity and mobility within organizational and occupational boundaries (Dokko/Wilk/Rothbard 2009; Greenhaus/Callanan 2012; Biemann/Zacher/Feldman 2012; Koch et al. 2017). This dissertation further aims at advancing our empirical understanding of top managers diversity, internationalisation and their careers. The three research manuscripts that form the core of this thesis advance research on top managers in several ways and extend knowledge in the area of executive characteristics. All three manuscripts are anchored in the European context and address topics that are relevant yet underexplored in extant, mostly centred in the US and Western economies top management literature (Tosi/Greckhamer 2004; Carter et al. 2009; Boyd et al. 2012; Dauth 2012).

Managerial characteristics have an important influence on strategy implementation. Previous studies have looked at the alignment of managerial characteristics with strategic type and aspects of performance. In all cases, the focus has been on corporate strategy and, predominantly, in private sector organisations. This study combines these objectives and investigates alignment between managerial characteristics, strategy and perceived performance. It focuses on management at the functional level in a public sector setting and demonstrates that classical upper-echelon theory is also relevant when applied at the functional level of management. The Miles and Snow (1978) typology is applied to the functional strategy for Dubai government organisations, to investigate whether functional units pursuing strategies are led by functional managers with dissimilar attributes, and whether the alignment between managerial characteristics and strategy is related to performance of the functional unit. Based on the extant literature, a research model has been developed, which yields two types of hypothesis. Data was collected by means of interviews and surveys to obtain knowledge of strategy types, and demographic and psychological characteristics for the functional managers. Regression techniques have been used for data analysis rendering support for two types of hypothesis. Consequently, this study supports the view that Upper Echelon theory can also apply at the functional level, emphasising the role of the functional managers, at the lower management levels of the organisations, in strategy implementation.

This paper examines the effect of executive board-level national culture and board nationality diversity on corporate social performance (CSP). The sample constitutes of 130 executive boards of non-financial firms from Germany, France, the Netherlands, Sweden, Switzerland and the UK over the time period 2010-2014. Based on the upper echelon theory and the notion of national culture, board-level national culture is determined across Hofstede’s dimensions of power distance, individualism, masculinity and power distance. In this paper, no evidence is provided of a significant relationship between board-level national culture and the corporate social performance of the firm. In addition, nationality diversity as a double-edged sword could both enhance and hamper CSP. In this research, no significant relationship between board nationality diversity and CSP is found. In conclusion, alterations of the board composition in terms of nationality in order to foster CSP seem unjustified based on the results of this paper.

One of the significant side-effects of growing urbanization is the constantly increasing amount of freight transportation in cities. This is mainly performed by conventional vans and trucks and causes a variety of problems such as road congestion, noise nuisance and pollution. Yet delivering goods to residents is a necessity. Sustainable concepts of city distribution networks are one way of mitigating difficulties of freight services. In this paper we develop a two-echelon city distribution scheme with temporal and spatial synchronization between cargo bikes and vans. The resulting heuristic is based on a greedy randomized adaptive search procedure with path relinking. In our computational experiments we use artificial data as well as real-world data of the city of Vienna. Furthermore we compare three distribution policies. The results show the costs caused by temporal synchronization and can give companies decision-support in planning a sustainable city distribution concept.

Two-echelon vehicle routing problems which contain synchronization between vehicles can be deeply impacted by time uncertainty, because one vehicle's delay can propagate to other vehicles. In this paper, we evaluate the deterministic solution of such a problem based on simulated travel time scenarios. The information obtained by simulation is incorporated in the optimization procedure iteratively. Computational results show that the degree of synchronization in an instance is directly correlated with the potential improvements by reoptimization. We present findings on the number of travel time scenarios required to obtain a representative picture of the stochastic solutions. In addition, we demonstrate that time dependent travel times can be aggregated on a city-wide level and linearized as a function of free flow times without major loss of reliability.

We report on an industrial project in which we developed an inventory model to provide decision support for the design and deployment of the field service support system for a remanufacturable product. The product was a dialysis unit for home use. Each unit that was installed in a home would eventually be removed due to failure, or the need for preventative maintenance, or the termination of the service. Upon removal, each unit was shipped to a central depot for re-manufacturing so that it could be returned to service. We develop a model to determine the inventory requirements at each regional depot, and then describe how to use the model to determine the inventory requirements in the two-echelon system consisting of the central facility and the regional depots. / Singapore-MIT Alliance (SMA)

Increased product proliferation and global competition are forcing companies within the supply chain to adopt new strategies. Postponement is an effective strategy that allows companies to be agile and cost effective in dealing with the dynamics of global supply chains. Postponement centres around delaying activities in the supply chain until real information about the market is available, which reduces the complexity and uncertainty of dealing with a proliferation of products. A two-echelon divergent supply chain entailing a central production facility and N retailers facing stochastic demand is studied within the inventory-distribution system. A periodic review order-up-to strategy is incorporated at all echelons. Unique to the study, five different systems are created and the effectiveness of several postponement strategies (form and transshipment) under various operational settings are compared. The importance of postponement under an integrated supply chain context and its contribution to various sector implementations are also discussed. Simulation is used to analyze the performance of the systems especially with respect to cost, order lead time and the effectiveness of transshipment policies. The study is unique in determining factors that favour one system implementation over another and distinguishing sector requirements that support postponement. In the study, postponement is found to be an effective strategy in dealing with managing item variety, demand uncertainty and differences in review periods in the two echelon supply chain for different experimental settings.