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Minimax in scheduling problems under uncertainty
Jeliga, Jan ; Branda, Martin (advisor) ; Lachout, Petr (referee)
In this work, we deal with fixed interval scheduling problems with the possibility of random delay of the end of the tasks (FIS). First, we pre- sent the basic deterministic FIS problems and ways to solve them. Next, we introduce the concept of minimax and present two well-known and one new FIS problem under uncertainty, when random task delays are conside- red to belong to a certain uncertainty set. Next, we deal with the solution of previously presented FIS problems for five chosen uncertainty sets. We present both previously achieved and original results. The work concludes with a summary of a numerical study of two problems. First, we explore the possibility of Lagrange relaxation application to the first presented problem. Next we explore the quality of approximation allowing to solve the later of problems as LP. 1
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Basic approaches to robust conditional value at risk
Nožička, Michal ; Branda, Martin (advisor) ; Petrová, Barbora (referee)
The work describes conditional value at risk, its robustification with respect to the probability distribution of yields of assets and its applications to optimal portfolio selection. In chapter one there are definitions of conditional value at risk and its generalization throught robustification and also motivation to these definitions. The basic properties of conditional value at risk, mainly coherence and continuity with respect to the parametr of confidence level, are discussed in chapter two. There is also shown that some of these properties are preserved after robustification. The third chapter is dedicated to the derivation of optimization problems of optimal portfolio selection on the basis of conditional value at risk and its robustification. This thesis describes only special cases so that the final problems are solveble by the means of linear programming. The fourth chapter describes particular utilization of these methods with usage of real data from financial markets. Powered by TCPDF (www.tcpdf.org)
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Robustness of the Markowitz portfolios
Petráš, Tomáš ; Dupačová, Jitka (advisor) ; Kopa, Miloš (referee)
This diploma thesis deals with the problem of portfolio optimization in relation to the mean vector and the variance matrix of yields. The emphasis is put on Mar- kowitz model. In the thesis there are explored some possibilities of robustification based on the used parametric set. Beside the classic formulation of the task our focus is also devoted to the cases in which short sales are not allowed. The core of the thesis constitutes of a simulation study that models the impact of errors in the estimation of the input parameters of Markowitz model. It takes into account different types of risk aversions and different approaches to modelling parameter perturbations . Therefore it specifies the hypothesis of the dominating influence of the mean vector estimate which is valid only for a risk lover. 1
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