Thesis (Ph.D)--Aerospace Engineering, Georgia Institute of Technology, 2009. / Committee Chair: Dimitri Mavris; Committee Member: Daniel Schrage; Committee Member: Hojong Baik; Committee Member: Jung-Ho Lewe; Committee Member: Kurt Neitzke. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Thèse--Strasbourg. / Bibliography: p. [257]-270.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1984. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 170-173).

Thesis (Ph.D.)--University of Texas at Dallas, 2007. / Includes vita. Includes bibliographical references (leaves 140-146)

The purpose of this study was to develop and empirically test the Supply Chain Integration Framework (SCI framework) in order to develop a framework to address the inefficiencies experienced in the public hospital pharmacies’ Supply Chain (SC) in Kenya. Supply Chain Management (SCM) can be regarded as a vibrant business entity that is changing and evolving continually because of constant changes in technology, competition and customer demands. The study investigated and analysed how the independent variables, namely SCI initiatives, performance improvement drivers, organisation environmental forces, workforce and management support, financial factors, flow and integration, regulatory framework and information sharing and technology influenced the SCI. The SCI was categorised into three components namely: customer order fulfilment, supplier collaboration and dedicated SC as the dependent variable. The literature reviewed established that globalisation and intensive worldwide competition, alongside technological developments, creates a completely new operating environment for organisations. The researcher reviewed various models and theories related to SCI which include systems theory, value chain models and value ecology models among others. An SCI framework was then developed to capture the interacting variables within the SCI network that could be adopted for the public hospital pharmacies in Kenya. The study was conducted using a survey questionnaire (Annexure B) that comprised both open and closed ended questions that were distributed to managers in public hospitals and pharmacies in Kenya. The population for the survey was 154 public hospital pharmacies in Kenya, with the final sample comprised of 280 respondents. The study was conducted using a survey questionnaire (Annexure B) that comprised both open and closed ended questions that were distributed to 325 respondents in 154 public hospitals and pharmacies in Kenya. The population for the survey was 154 public hospital pharmacies in Kenya, with the final sample comprised of 280 respondents. Exploratory factor analysis was used to ascertain the validity of the measuring instrument and the Cronbach alpha coefficients were used to measure the reliability of the measuring instruments. Key preliminary tests performed were the Kaiser-Meyer-Olkin test (KMO test) of sample adequacy, the Bartlett’s test of sphericity and the Kolmogorov-Smirnov test (Z-Statistic test) for normality and multi-collinearity diagnostic. Analysis of Variance (ANOVA) and multiple linear regressions were the main statistical procedures used to test the regression model fit and the significance of the relationships hypothesised among various variables in the study. Statistical softwares, namely Statistica 10 (2010) and Statistical Package for Social Sciences (SPSS) Version 18, were used to analyse quantitative data. The study identified five statistically significant relationships between customer order fulfilment and workforce and management support, financial factors, flow and integration, information sharing and technology, supplier collaborations and dedicated SCI. In addition, a total of six statistically significant relationships exist between the supplier collaborations and SCI initiatives i.e. performance improvement drivers, workforce and management support, financial factors, flow and integration, information sharing and technology adoption as well as dedicated SCI. Furthermore, four statistically significant relationships were found between dedicated SCI and SCI initiatives, workforce and management support, financial factors, flow and integration, information sharing and technology adoption.

In this thesis, we study the statistical issues in lost sales inventory systems, focusing on the complexity arising from the stochastic demand. We model the demand by the Zero Inflated Poisson (ZIP) distribution. The maximum likelihood estimator of the ZIP parameters taking censoring into account are derived separately for the newsvendor and the (s, S) inventory systems. We also investigate the effect of the estimation errors on the optimal policies and their costs. We observe from a simulation study that the MLE taking censoring into account performed the best in terms of cost as well as policy among various estimates. We then proceed to develop a Bayesian dynamic updating scheme of the ZIP parameters. It is applied to the newsvendor system. We perform a simulation study to investigate the advantage of the Bayesian updating approach over the traditional MLE approach. We conclude that the Bayesian pproach offers a better learning technique when one lacks of good understanding of the demand pattern in the first few periods. Since inventory policy affects the information acquisition and-the demand distribution updating process, how to determine the optimal inventory policy when the demand distribution is yet to be learned is the focus of the latter part of the thesis. We investigate the effect of demand censoring on the optimal policy in newsvendor inventory models with general parametric demand distribution and unknown parameter values. We provide theoretical proof of the conjecture that it is better off to adopt a higher than the myopic optimal policy in the initial periods when demand is learned in a censoring system. We show that the newsvendor problem with observable lost sales reduces to a sequence of single-period problems while the newsvendor problem with unobservable lost sales requires a dynamic analysis. We explore the economic rationality for this observation and illustrate it with numerical examples. / Business, Sauder School of / Graduate

The three essays in this thesis address various problems in the general area of supply chain management. In general, supply chain management is concerned with management of the flow of goods, information, and funds among supply chain members, such as suppliers, manufacturers, distributors, retailers, and consumers. As such, its scope includes timing and quantity of material flow, logistics, improving efficiencies in problems with several decision makers, etc. The first essay in this thesis considers the problem of improving coordination in a decentralized system of retailers, while the second one addresses stability and profitability of Internet-based supply exchange alliances. The third essay analyzes a logistics problem, of finding an optimal route for a capacitated vehicle which travels on a graph and which can perform pickups and deliveries. In the first essay, we study a three-stage model of a decentralized distribution system with n retailers who each faces a stochastic demand for an identical product. In the first stage, before the demand is realized, each retailer independently orders her initial inventory. In the second stage, after the realization of the demand, each retailer decides what portion of her residual supply/demand she wants to share with the other retailers. In the third stage, residual inventories are transshipped in order to possibly meet residual demands, and an additional profit is allocated among the retailers. We study the effect of implementing various allocations rules in the third stage on the levels of the residual supply/demand the retailers are willing to share with others in the second stage, and the tradeoff involved in achieving a solution which is also optimal for the corresponding centralized system. The second essay is concerned with the formation of Internet-based supply exchange alliances among three or fewer retailers of possibly substitutable products. We provide some conditions, in terms of product substitutability and quality of suppliers, which would lead to the formation of a three member alliance, or a two member alliance, or no alliance at all. We also study the effect of alliance structure and quality of suppliers on the profit of a retailer. The third essay considers a vehicle routing problem with pickups and deliveries (VRPD problem) on some special graphs. Some vertices on the graph represent delivery customers, and other vertices represent pickup customers. The objective is to find a minimum length tour for a capacitated vehicle, which starts at a depot and travels on the graph while satisfying all the requests by the customers without violating the vehicle capacity constraint, and returns to a depot. We have developed linear time algorithms for the VRPD problem on a path and on tree graphs, linear and O (|V| log |V|) algorithm for a VRPD problem defined on a path with parametric initial capacity, and quadratic and O (|V|² log |V|) algorithms for a VRPD problem defined over a cycle graph. / Business, Sauder School of / Graduate

While Malawi’s Farm Input Subsidy Program (FISP) has been the focus of numerous studies on the impacts of subsidies on farm-household income, yields, fertilizer use and adoption, there still has not been much empirical work quantifying the program’s effects on maize supply and demand. In this study, we use the econometric framework proposed by Roberts and Schlenker (2013) to identify the effect of FISP on maize production as well as supply and demand price elasticities in Malawi. We use national aggregate data and find that the program has increased aggregate maize supply. Our results show that FISP has had an aggregate effect across years of about 3,746,870 metric tons from 2006-2013. We also find that the program has increased farmers’ responsiveness to changes in fertilizer prices. However, our estimates suggest that higher prices lead to higher quantities of fertilizer demanded, a relationship that is not consistent with economic theory.

No description available.

This study is concerned with the problem of locating p capacitated facilities on a chain graph, and simultaneously determining the allocation of their supplies in order to satisfy a continuum of demand which is characterized by some weighted probability density function defined on the chain graph. The objective is to minimize the total (expected) transportation cost. This location-allocation problem is also referred to as the capacitated p-median problem on a chain graph. Two unbalanced cases of this problem are considered, namely, the over-capacitated case when total supply exceeds total demand, and the deficit capacity case when total supply is less than total demand. Both these problems are nonconvex, and are shown to be NP-hard even if the demand density function is piecewise uniform and positive. We provide a first-order characterization of optimality for these two problems, and prescribe an enumerative algorithm based on a partitioning of the dual space in order to optimally solve them. An extension of these algorithms for solving the capacitated, unbalanced 2-median problem on a tree graph is also given. / M.S.