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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Studies of inventory control and capacity planning with multiple sources

Zahrn, Frederick Craig 06 July 2009 (has links)
This dissertation consists of two self-contained studies. The first study, in the domain of stochastic inventory theory, addresses the structure of optimal ordering policies in a periodic review setting. We take multiple sources of a single product to imply an ordering cost function that is nondecreasing, piecewise linear, and convex. Our main contribution is a proof of the optimality of a finite generalized base stock policy under an average cost criterion. Our inventory model is formulated as a Markov decision process with complete observations. Orders are delivered immediately. Excess demand is fully backlogged, and the function describing holding and backlogging costs is convex. All parameters are stationary, and the random demands are independent and identically distributed across periods. The (known) distribution function is subject to mild assumptions along with the holding and backlogging cost function. Our proof uses a vanishing discount approach. We extend our results from a continuous environment to the case where demands and order quantities are integral. The second study is in the area of capacity planning. Our overarching contribution is a relatively simple and fast solution approach for the fleet composition problem faced by a retail distribution firm, focusing on the context of a major beverage distributor. Vehicles to be included in the fleet may be of multiple sizes; we assume that spot transportation capacity will be available to supplement the fleet as needed. We aim to balance the fixed costs of the fleet against exposure to high variable costs due to reliance on spot capacity. We propose a two-stage stochastic linear programming model with fixed recourse. The demand on a particular day in the planning horizon is described by the total quantity to be delivered and the total number of customers to visit. Thus, daily demand throughout the entire planning period is captured by a bivariate probability distribution. We present an algorithm that efficiently generates a "definitive" collection of bases of the recourse program, facilitating rapid computation of the expected cost of a prospective fleet and its gradient. The equivalent convex program may then be solved by a standard gradient projection algorithm.
12

Vícekriteriální analýza portfolia ve spojení s parametrickým programováním / Multi-criteria portfolio analysis in conjunction with parametric programming

Hofmanová, Andrea January 2014 (has links)
The presented diploma thesis deals with the issue of multi-criteria decision making in practice. The main aim is to demonstrate the possibilities of involvement the parametric programming in multi-criteria linear programming (MCLP). The first, theoretically oriented chapter, describes the necessary theoretical knowledge. In this chapter is presented the role of financial planning together with essential relationships, by which is determined the rest of the work. This chapter also discusses the issue of multi-criteria linear programming including a description of selected a priori methods. The selected a priori methods are lexicographic method, utility function method, minimization of the distance from the ideal solution and minimal component method. The second chapter is devoted to the practical application of multi-criteria optimization portfolio with a parametric budget. For all the analyzed methods are firstly discussed models without integer conditions, and consequently their modification with these conditions. For the purpose of this work was used solver in MS Excel spreadsheet along with the created macro.
13

Matematický model rozpočtu / Mathematical Model for Faculty Budget

Holá, Lucie January 2008 (has links)
The idea of this diploma thesis is an origin application of optimization models to solve a wage funds allocation problem on various institutes of each faculty. This diploma thesis includes an outline of linear programming models, nonlinear programming models, multiply programming models and parametric programming models. Studied questions are debating in wider context of distributing financial resources from the Budget of the Czech republic, through Ministry of education, youth and sports, universities, faculties after as much as various institutes. The accent is given on question of definition assessment scales of achievement criteria with general-purpose kvantification.
14

Možnosti systému Sinumerik při programování CNC obráběcích strojů / Sinumerik tools for programming of CNC machines

Kulenda, Martin January 2011 (has links)
The master’s thesis incorporates the control system Sinumerik 840D to the most widely used control systems of CNC machine tools. In the first thesis part are analyzed the NC programming methodics, which are relative only to the control system Sinumerik 840D and an essentials necessary to understand the issue in the area of CNC machine tools. Next part of the thesis includes design of the technology and processing of the NC program for machined component (gearbox cover). The NC program is made by ShopMill that is focused on a workshop area. During the program creation is combined a ShopMill and parametric programming, with using of a conditional jump instructions and repetitions. The final part of the thesis includes verification of the selected component production process by simulation and technical-economic evaluation of the designed technology.
15

Supervisory model predictive control of building integrated renewable and low carbon energy systems

Sadr, Faramarz January 2012 (has links)
To reduce fossil fuel consumption and carbon emission in the building sector, renewable and low carbon energy technologies are integrated in building energy systems to supply all or part of the building energy demand. In this research, an optimal supervisory controller is designed to optimize the operational cost and the CO2 emission of the integrated energy systems. For this purpose, the building energy system is defined and its boundary, components (subsystems), inputs and outputs are identified. Then a mathematical model of the components is obtained. For mathematical modelling of the energy system, a unified modelling method is used. With this method, many different building energy systems can be modelled uniformly. Two approaches are used; multi-period optimization and hybrid model predictive control. In both approaches the optimization problem is deterministic, so that at each time step the energy consumption of the building, and the available renewable energy are perfectly predicted for the prediction horizon. The controller is simulated in three different applications. In the first application the controller is used for a system consisting of a micro-combined heat and power system with an auxiliary boiler and a hot water storage tank. In this application the controller reduces the operational cost and CO2 emission by 7.31 percent and 5.19 percent respectively, with respect to the heat led operation. In the second application the controller is used to control a farm electrification system consisting of PV panels, a diesel generator and a battery bank. In this application the operational cost with respect to the common load following strategy is reduced by 3.8 percent. In the third application the controller is used to control a hybrid off-grid power system consisting of PV panels, a battery bank, an electrolyzer, a hydrogen storage tank and a fuel cell. In this application the controller maximizes the total stored energies in the battery bank and the hydrogen storage tank.

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