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The parasitoid community of two microlepidopteran species living on hops
Hovorka, Tomáš ; Janšta, Petr (advisor) ; Libra, Martin (referee)
Interactions between parasitoids, phytophagous insects and their host plants play one of the crucial role in the trophic relationships of terrestrial food webs. According to current knowledge, more than half of all known terrestrial species are part of this food web (parasitoids- herbivores-plants). In many species of herbivore hosts, interactions with parasitoids have led to the evolution and diversification of different defense strategies. An example of a primary defense strategy against predators and parasitoids is the formation of shelters such as leaf mines, leaf cocoons or galls. These strategies are a key factor influencing the composition of the parasitoid community. In this thesis, the complex of parasitoids in two microlepidopteran species with different life strategies living on hops (Humulus lupulus) was investigated. The caterpillars of Caloptilia fidella (Lepidoptera: Gracillaridae) first mine within leaves of hops, later, when they start to feed exophagously, they create leaf rolls and cocoons on the outer surface of the leaf. Caterpillars of the species Cosmopterix zieglerella (Lepidoptera: Cosmopterigidae) remain in the mine throughout their larval development. The obtained parasitoids were identified both based on morphology and with the help of two gene fragments, namely CO1 and...
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Data fusion
Janíková, Veronika ; Hovorka, Tomáš (advisor) ; Anděl, Jiří (referee)
This bachelor's thesis deals with a data fusion, which is a one of the possible solutions to the common problem of data availability in praxis. In the first part, practical use of data fusion, especially in marketing, fundamental algorithms and data fusion problems are discussed. The main part of this thesis deals with the so-called "unconstrained statistical fusion". Firstly, one of the possible processes of this type of fusion is described theoretically in detail. This process involves branching into four different types of data fusion. Next, a method of theoretical evaluating the quality of the general fusion model is designed using statistical indicators. The practical part of the thesis contents processes of four types of unconstrained statistical fusion and their evaluation which both are programmed in statistical program R. Furthermore, the fusion is applied to our artificially generated database and also to a real data collected in praxis by Czech public opinion research company Median. In the very last part of the thesis, the results of fusions applied to these two databases are interpreted, evaluated and discussed.
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Importance sampling
Hovorka, Tomáš ; Hlávka, Zdeněk (referee) ; Antoch, Jaromír (advisor)
In the present work we study the important sampling method. This method serves as a variance reduction technique for the Monte Carlo simulations. The basic theoretical properties of important sampling estimators are shown. A number of methods how to choose an alternative density is presented and compared on many examples. Among others: translation and scaling of original density, dominating point method, random translation over the surface of d-dimensional sphere method and method combining translation and scaling of original density. In the conclusion we attempted to set up some rules for choosing an appropriate method in dependence on the form of the problem to be solved.
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