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Towards classification and terminology of early life history stages in fishes
Peňáz, Milan
This review paper analyses and describes main approaches in the classification of fish ontogeny and concerning terminology, it tries to summarize main results obtained as well as to point out and to discuss the main existing confusing problems, such a differently understood and differently demarcated larval and juvenile life history periods. Important role of absolute yolk amount on the character of early ontogeny, with consequencies on the strategies of reproduction a population dynamics is also emsized.
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Okrajový jev v mnohorozměrných datech
Jiřina, Marcel ; Jiřina jr., M.
In this paper we show some strange features of multidimensional data and their influence on classification. We introduce the probability distribution mapping function, and the distribution density mapping function which maps probability density distribution of points in n-dimensional space to a similar distribution in one-dimensional space of distances. The power approximation of the probability distribution mapping function is introduced and an application for a probability density estimation including the boundary effect in high dimensions is shown. Some results obtained with the new method for classification are shown.
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Classification of electronic documents using cluster analysis
Ševčík, Radim ; Řezanková, Hana (advisor) ; Svátek, Vojtěch (referee)
The current age is characterised by unprecedented information growth, whether it is by amount or complexity. Most of it is available in digital form so we can analyze it using cluster analysis. We have tried to classify the documents from 20 Newsgroups collection in terms of their content only. The aim was to asses available clustering methods in a variety of applications. After the transformation into binary vector representation we performed several experiments and measured the values of entropy, purity and time of execution in application CLUTO. For a small number of clusters the best results offered the direct method (generally hierarchical method), but for more it was the repeated bisection (divisive). Agglomerative method proved not to be suitable. Using simulation we estimated the optimal number of clusters to be 10. For this solution we described in detail features of each cluster using repeated bisection method and i2 criterion function. In the future focus should be set on realisation of binary clustering with advantage of programming languages like Perl or C++. Results of this work might be of interest to web search engine developers and electronic catalogue administrators.
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Mezipodnikové srovnávání
Křižková, Jana ; Vávrová, Hana (advisor) ; Tyll, Ladislav (referee)
Práce se zabývá mezipodnikovým srovnáváním deseti textilek v České republice za časové období 2006-2008. Jsou aplikovány jedno a vícerozměrné metody mezipodnikového srovnávání a určeno pořadí společností dle každé z nich. Dále jsou podniky rožčleněny do skupin s využitím klasifikační analýzy a na závěr jsou data graficky znázorněna ve spidergramu. Diskutovány jsou výhody a nevýhody jednotlivých metod.
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