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Description of Old Czech Common Nouns Declension (with regard to Automatic Morphological Analysis of Texts in Old Czech Text Bank)
Synková, Pavlína ; Oliva, Karel (advisor) ; Petkevič, Vladimír (referee) ; Vepřek, Miroslav (referee)
The thesis aims at explicit description of Old Czech common nouns declension with regard to its application in a tool for automatic morphological analysis of (digitized) texts in Old Czech. This means that this description is intended to serve as a basis for automatic generation of word forms (jointly with their appropriate morphological information and lemma) which will then be used for assigning morphological categories (gender, number, case) and lemma to word forms occurring in Old Czech digitized texts. The thesis thus develops a base for the first step in transformation of text banks (which currently exist for the Old Czech period) into an Old Czech corpus offering more possibilities for linguistic research. The Old Czech period is defined as a period from the beginning of the 14th century (more precisely from the period when first coherent texts written in Czech appeared) approx. to the end of the 15th century. Nouns were chosen for this work, because they cover approx. 30% of texts in current Czech (which is the highest percentage from all parts of speech). Old Czech texts are taken into account only in a transcribed form (based on transcription rules used in the Old Czech Text Bank developed at the Institute of the Czech Language of the Academy of Sciences of the Czech Republic). On the one...
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Automatic Creation of Dictionaries from Translations
Sumbalová, Lenka ; Kouřil, Jan (referee) ; Smrž, Pavel (advisor)
The aim of this bachelor thesis was to make a system for automatic creation of dictionaries from translations. It describes the implementation of a system that generates Czech-English dictionary from the aligned parallel corpus and summarizes the results. It also analyzed CzEng parallel corpus, which was used as the data source for dictionaries and explainS the theoretical concepts related to this topic.
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Stemming of Czech Words
Hellebrand, David ; Bartík, Vladimír (referee) ; Chmelař, Petr (advisor)
The goal of this master's thesis is to develop stemming algorithm for czech language based on grammatical rules. You can find a description of stemming process and a comparsion of stemming algorithms in this project. The basics of czech grammar and Snowball language are also described here. The main part of this thesis concerns the implementation of the new czech stemming algorithm.
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Czech-English Translation
Petrželka, Jiří ; Schmidt, Marek (referee) ; Smrž, Pavel (advisor)
Tato diplomová práce popisuje principy statistického strojového překladu a demonstruje, jak sestavit systém pro statistický strojový překlad Moses. V přípravné fázi jsou prozkoumány volně dostupné bilingvní česko-anglické korpusy. Empirická analýza časové náročnosti vícevláknových nástrojů pro zarovnání slov demonstruje, že MGIZA++ může dosáhnout až pětinásobného zrychlení, zatímco PGIZA++ až osminásobného zrychlení (v porovnání s GIZA++). Jsou otestovány tři způsoby morfologického pre-processingu českých trénovacích dat za použití jednoduchých nefaktorových modelů. Zatímco jednoduchá lemmatizace může snížit BLEU, sofistikovanější přístupy většinou BLEU zvyšují. Positivní efekty morfologického pre-processingu se vytrácejí s růstem velikosti korpusu. Vztah mezi dalšími charakteristikami korpusu (velikost, žánr, další data) a výsledným BLEU je empiricky měřen. Koncový systém je natrénován na korpusu CzEng 0.9 a vyhodnocen na testovacím vzorku z workshopu WMT 2010.
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Parallel Corpus Manager
Kouřil, Jan ; Dytrych, Jaroslav (referee) ; Smrž, Pavel (advisor)
The goal of diploma project was to implement parallel corpus manager, which can align parallel texts in different languages and insert them into corpus, where several more processing functions are provided. Program provides possibilities of automatic text alignment and its interactive editing. These aligned texts are then inserted into corpus. Program can work with multiple corpora, parallel corpus is allways identified by a couple of languages. In corpus, there are possibilities to search by many categories, view and edit particular selections, lemmatize and morphologically tag given texts, sort selections, import and export data, in many ways edit corpus for further easy navigation and add new expressions to managed dictionaries. Particular chapters describe introduction to corpus problematics, theory of aligning parallel texts, morphological text tagging and lemmatization, external tools used in program, most common subtitle formats and implementation solution of particular problems.
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Determination of basic form of words
Šanda, Pavel ; Burget, Radim (referee) ; Karásek, Jan (advisor)
Lemmatization is an important preprocessing step for many applications of text mining. Lemmatization process is similar to the stemming process, with the difference that determines not only the word stem, but it´s trying to determines the basic form of the word using the methods Brute Force and Suffix Stripping. The main aim of this paper is to present methods for algorithmic improvements Czech lemmatization. The created training set of data are content of this paper and can be freely used for student and academic works dealing with similar problematics.
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Recognition of emotions in Czech texts
Červenec, Radek ; Smékal, Zdeněk (referee) ; Burget, Radim (advisor)
With advances in information and communication technologies over the past few years, the amount of information stored in the form of electronic text documents has been rapidly growing. Since the human abilities to effectively process and analyze large amounts of information are limited, there is an increasing demand for tools enabling to automatically analyze these documents and benefit from their emotional content. These kinds of systems have extensive applications. The purpose of this work is to design and implement a system for identifying expression of emotions in Czech texts. The proposed system is based mainly on machine learning methods and therefore design and creation of a training set is described as well. The training set is eventually utilized to create a model of classifier using the SVM. For the purpose of improving classification results, additional components were integrated into the system, such as lexical database, lemmatizer or derived keyword dictionary. The thesis also presents results of text documents classification into defined emotion classes and evaluates various approaches to categorization.
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Effect of the Czech Stemming Algorithm on the Document Retrieval
Pytelka, Petr ; Strossa, Petr (advisor) ; Pinkas, Otakar (referee)
This thesis deals with the measurement of the quality of the stemming/lemmatization algo-rithm for the Czech language in document processing systems and provides an analysis of the results. The theoretical part of the thesis describes the principles of the full-text search, the possibilities of implementation as well as the common problems which have to be solved in connection with the processing of natural language. Methods of evaluating the quality of lemmatization, using recall and precision, are discussed. In addition, the theoret-ical part covers the method of measuring the index of under-stemming and over-stemming, which can be applied for the purposes of a more detailed evaluation. An experiment for evaluating the lemmatization algorithms is proposed in the second part of the thesis. A specialized application has been developed to perform the experiment in three different systems, namely Apache Lucene, the PostgreSQL database systems and the Microsoft SQL Server. The experiment is based on the Prague Dependency Treebank cor-pus. It has been carried out both for the corpus as a whole and for selected word classes separately. Further analysis of the results for Czech stemmer in Apache Lucene leads to a proposal for several modifications of the algorithm. Such modifications result in measurable improvements. The results achieved show how metrics discussed, together with the values measured, can be used for improving the lemmatization algorithms and thus to improve the full-text search for Czech language.
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