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Derivational Morphology of Czech on Large Corpus Data
Faltusová, Marie ; Dytrych, Jaroslav (referee) ; Smrž, Pavel (advisor)
Subject of this thesis is study of word formation in the Czech language. The main aim is to create a module acquiring derivations from data of the electronic Dictionary of the Czech Language. This problematics has been solved by constructing three-level processing based on dictionary data. The first level is to obtain derivations from lemma definitions, the second step is making groups of basic forms according to their similarities, and the third stage is the evaluation of derivation pairs by number tag of derivation class to which they belong. I have managed to get more than 4 500 new words and evaluate over 20 000 derivative couples. The module has become a full-fledged part of the Morphological Analyzer of the Knowledge Technology Research Group, working at the Faculty of Information Technology of the Brno University of Technology.
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Morphological Segmentation in Czech using Word-Formation Network
Bodnár, Jan ; Žabokrtský, Zdeněk (advisor) ; Hana, Jiří (referee)
Morphological segmentation is segmentation of words into morphemes - smallest units carrying meaning. It is a low level Natural Language Processing task. Since morphological segmentation is sometimes used as method of preprocessing, achieving better results on this task may help NLP algorithms to better solve various problems, especially in scenarios involving small amount of data, and it may also also help the linguistic research. We propose a novel ensemble algorithm for morphological segmentation of Czech lemmas which makes use of the DeriNet derivation tree dataset. As a sideproduct we also created suggestions for improvements of the DeriNet dataset.
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Morphological segmentation of Czech Words
Vidra, Jonáš ; Žabokrtský, Zdeněk (advisor) ; Mareček, David (referee)
In linguistics, words are usually considered to be composed of morphemes: units that carry meaning and are not further subdivisible. The task of this thesis is to create an automatic method for segmenting Czech words into morphemes, usable within the network of Czech derivational relations DeriNet. We created two different methods. The first one finds morpheme boundaries by differentiating words against their derivational parents, and transitively against their whole derivational family. It explicitly models morphophonological alternations and finds the best boundaries using maximum likelihood estimation. At worst, the results are slightly worse than the state of the art method Morfessor FlatCat, and they are significantly better in some settings. The second method is a neural network made to jointly predict segmentation and derivational parents, trained using the output of the first method and the derivational pairs from DeriNet. Our hypothesis that such joint training would increase the quality of the segmentation over training purely on the segmentation task seems to hold in some cases, but not in other. The neural model performs worse than the first one, possibly due to being trained on data which already contains some errors, multiplying them.
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Derivational Morphology of Czech on Large Corpus Data
Faltusová, Marie ; Dytrych, Jaroslav (referee) ; Smrž, Pavel (advisor)
Subject of this thesis is study of word formation in the Czech language. The main aim is to create a module acquiring derivations from data of the electronic Dictionary of the Czech Language. This problematics has been solved by constructing three-level processing based on dictionary data. The first level is to obtain derivations from lemma definitions, the second step is making groups of basic forms according to their similarities, and the third stage is the evaluation of derivation pairs by number tag of derivation class to which they belong. I have managed to get more than 4 500 new words and evaluate over 20 000 derivative couples. The module has become a full-fledged part of the Morphological Analyzer of the Knowledge Technology Research Group, working at the Faculty of Information Technology of the Brno University of Technology.
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Prefixation in Contemporary Spanish
Řepíková, Kamila ; Čermák, Petr (advisor) ; Kratochvílová, Dana (referee)
This diploma thesis takes a comprehensive look at the matter of prefixation in contemporary Spanish and it is therefore divided into two parts. In the first one, we occupy ourselves with the area of constructional morphology and tackle theoretical matters. From the more general topics of word formation we then proceed to prefixation itself which we then attempt to define and describe in more detail. We outline the issues of concept delimitations, definition of prefixation, classification of prefixes and other controversial matters related to this process in the Spanish language. The second part of the thesis is of a more practical nature. There, we focus on the semantic meanings (locative and gradative) some prefixes may acquire. We then concentrate on specific prefixes (entre-, inter-, sobre-, super-), their distribution among word classes, and finally, using InterCorp, a parallel language corpus, we study Czech equivalents of selected elements.
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Multigrammars and Parsing Based on Them
Fiala, Jiří ; Lukáš, Roman (referee) ; Meduna, Alexandr (advisor)
This document deals with introduction focused on pragmatically oriented research at branch of theoretical computer science and with presentation of designed methods for chosen application topics. At this study the theoretical subject is represented by kind of generative system - multisequential grammar and application topics are chosen according to possibilities supported by multisequential grammars. In order to follow results published by Thompson (see [9]), Lindenmayer (see [26]), Mandelbrot (see [8]) and also studies published by Morneau (see [17]), which shows the relation between natural laws and human discipline - mathematics, we study the applications of multi-sequential grammars from two points of view: generative L-systems (which further includes applications of fractal geometry and biomathematics) and natural language processing (which further includes the design of proper abstract language). Some problems related to compiler construction are also mentioned.
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