Browsing by Subject "distribution"

Now showing 1 - 4 of 4

Open Access
Capital's response to globalization : "a comparative analysis of the adjustment patterns of mark-ups in post-liberalization developing countries"
(2004) Buturak, Gökhan
In this thesis, I investigate the capital’s response to the new world economic order termed as “globalization”. It is asserted in many theoretical and popular writings that increased pressures of global competition would squeeze the profit margins and reduce capital returns. I discuss this proposition theoretically and then test for it using manufacturing data for a selected group of developing countries under post-liberalization. I utilize time series and panel data econometrics to study the behavior of markups (gross profit margins) against wage costs, trade openness, and investment share in the GDP as a proxy for capacity utilization. Contrary to expectations, I find no significant conclusive evidence on the sign of “openness” on profit margins in many countries of my sample. My results also reveal that though mark-ups are negatively related with real wage costs in most of the Latin American countries in my sample, they have a positive and statistically significant relation to real wage costs in Turkish manufacturing. Finally, investment shares and mark-ups reveal a negative relationship for Argentina and Turkey and a positive one for Colombia.
Open Access
Integrated scheduling of production and logistics operations of a multi-plant manifacturer serving a single customer area
(2009) Çelen, Merve
Increasing market competition forces manufacturers to continuously reduce their leadtimes by minimizing the total time spent in both production and distribution. Some studies in the relevant literature indicate that scheduling production and logistics operations in a coordinated manner leads to improved results. This thesis studies the problem of scheduling production and distribution operations of a manufacturer serving a single customer area from multiple identical production plants dispersed at different geographical locations. The products are transported to the customer area by a single capacitated truck. The setting is inspired by the operations of a leading soft drink manufacturer, and the objective is set in line with their needs as the minimization of the total completion time of the jobs. The completion time of a job is defined as the time it reaches at the customer area. We consider both this general problem and four special cases motivated by common practical applications. We prove that both the main problem and three of its special cases are NP-hard at least in the ordinary sense. We develop mixed integer programming (MIP) models for all these problems and propose a pseudo-polynomial dynamic programming mechanism for the remaining special case. Since the MIP models are able to provide optimal solutions only for small instances in a reasonable amount of time, heuristics are also proposed to solve larger instances. Fast lower bounds are developed to facilitate the performance assessment of these heuristics in medium and large instances. Evidence from extensive computational experimentation suggests that the proposed heuristics are both efficient and effective.
Open Access
A mobile ammunition distribution system design on the battlefield
(2010) Toyoğlu, Hünkar
Ammunition has been the most prominent factor in determining the outcome of combat. In this dissertation we study a military logistics problem in which ammunition requirements of the combat units, which are located on the battle- field, are to be satisfied in the right amount when and where they are needed. Our main objective is to provide a decision support tool that can help plan ammunition distribution on the battlefield. We demonstrate through an extensive literature review that the existing models are not capable of handling the specifics of our problem. Hence, we propose a mathematical programming model considering arc-based product-flow with O(n 4 ) decision variables and constraints. The model is a three-layer commodity-flow location routing formulation that distributes multiple products, respects hard time windows, allows demand points to be supplied by more than one vehicle or depot, and locates facilities at two different layers. We then develop a new mathematical programming model with only O(n 3 ) decision variables and constraints by considering node-based product-flow. We derive several valid inequalities to speed up the solution time of our models, illustrate the performance of the models in several realistically sized scenarios, and report encouraging results. Based on these mathematical models we propose two three-phase heuristic methods: a routing-first location-second and a location- first routing-second heuristic. The computational results show that complex real world problems can effectively be solved in reasonable times with the proposed heuristics. Finally, we introduce a dynamic model that designs the distribution system in consecutive time periods for the entire combat duration, and show how the static model can be utilized in dynamic environments.
Open Access
Review of an approach to obstruction theory
(1994) Kırdar, Mehmet
In this work, we summarized an approach to obstruction tlieory developed by E. Thomas. We gave some illustrative examples to demonstrate the method. These are : 2-plane fields on manifolds revi(iwing works of Thotnas, 3 and 4 fields on (4k-f3)-dimensional manifolds.