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Design and Implementation of System for Aggregations of Real Estate Offers in the Czech Republic
Drobník, Jakub ; Kučera, Jan (advisor) ; Chlapek, Dušan (referee)
The diploma thesis deals with the design and implementation of software for aggregations of real estate offers in the Czech Republic. The aim of the thesis is to create a system which aggregates the data of real estate offers from web pages. This thesis consists of two basic parts. The context of creating the system is described in the first part. The author discusses ways to retrieve data from websites - especially the extraction of data using automated robots - in the first part of the thesis. The design and implementation of the system are described in the second part. The author and sponsor define requirements for the system in the second part of the thesis. The outcome of this thesis is a prototype that aggregates data from real estate portals into the prepared database. The main contribution of the thesis is an example of a possible approach that can aggregate data from a particular market segment and put it into the database.
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Web application for matching business offers and requests built on top of Linked Data principles
Snoha, Matej ; Nečaský, Martin (advisor) ; Svoboda, Martin (referee)
The aim of this thesis is to design, develop and test a set of web application components built on top of Linked Data principles. This application works with public procurement data made available thanks to the OpenData.cz initiative. The role of the components developed is matching of business offers and requests as well as comparison of public contracts. Introduced are Semantic Web technologies in the context of web application development, an abstract component for the development of web applications using Linked Data as well as developed components based on it. In this work, we have gone through the application lifecycle, from analysis of available technologies and the requirements for the application through design of the application and its individual layers up to implementation of required functionality and subsequent deployment of functional application. 1
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Semantic annotations
Dědek, Jan ; Vojtáš, Peter (advisor) ; Maynard, Diana (referee) ; Železný, Filip (referee)
Four relatively separate topics are presented in the thesis. Each topic represents one particular aspect of the Information Extraction discipline. The first two topics are focused on our information extraction methods based on deep language parsing. The first topic relates to how deep language parsing was used in our extraction method in combination with manually designed extraction rules. The second topic deals with a method for automated induction of extraction rules using Inductive Logic Programming. The third topic of the thesis combines information extraction with rule based reasoning. The core of our extraction method was experimentally reimplemented using semantic web technologies, which allows saving the extraction rules in so called shareable extraction ontologies that are not dependent on the original extraction tool. The last topic of the thesis deals with document classification and fuzzy logic. We are investigating the possibility of using information obtained by information extraction techniques to document classification. Our implementation of so called Fuzzy ILP Classifier was experimentally used for the purpose of document classification.
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Modelování událostí na sémantickém webu
Hanzal, Tomáš ; Svátek, Vojtěch (advisor) ; Vacura, Miroslav (referee)
There are many ontologies and datasets on the semantic web that mention events. Events are important in our perception of the world and in our descriptions of it, therefore also on the semantic web. There is however not one best way to model them. This is connected to the fact that even the question what events are can be approached in different ways. Our aim is to better understand how events are represented on the semantic web and how it could be improved. To this end we first turn to the ways events are treated in philosophy and in foundational ontologies. We ask questions such as what sorts of things we call events, what ontological status we assign to events and if and how can events be distinguished from other entities such as situations. Then we move on to an empirical analysis of particular semantic web ontologies for events. In this analysis we find what kinds of things are usually called events on the semantic web (and what kinds of events there are). We use the findings from the philosophy of events to critically assess these ontologies, show their problems and indicate possible paths to their solution.
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Extrakce informací z webových stránek pomoci extrakčních ontologií
Labský, Martin ; Berka, Petr (advisor) ; Strossa, Petr (referee) ; Vojtáš, Peter (referee) ; Snášel, Václav (referee)
Automatic information extraction (IE) from various types of text became very popular during the last decade. Owing to information overload, there are many practical applications that can utilize semantically labelled data extracted from textual sources like the Internet, emails, intranet documents and even conventional sources like newspaper and magazines. Applications of IE exist in many areas of computer science: information retrieval systems, question answering or website quality assessment. This work focuses on developing IE methods and tools that are particularly suited to extraction from semi-structured documents such as web pages and to situations where available training data is limited. The main contribution of this thesis is the proposed approach of extended extraction ontologies. It attempts to combine extraction evidence from three distinct sources: (1) manually specified extraction knowledge, (2) existing training data and (3) formatting regularities that are often present in online documents. The underlying hypothesis is that using extraction evidence of all three types by the extraction algorithm can help improve its extraction accuracy and robustness. The motivation for this work has been the lack of described methods and tools that would exploit these extraction evidence types at the same time. This thesis first describes a statistically trained approach to IE based on Hidden Markov Models which integrates with a picture classification algorithm in order to extract product offers from the Internet, including textual items as well as images. This approach is evaluated using a bicycle sale domain. Several methods of image classification using various feature sets are described and evaluated as well. These trained approaches are then integrated in the proposed novel approach of extended extraction ontologies, which builds on top of the work of Embley [21] by exploiting manual, trained and formatting types of extraction evidence at the same time. The intended benefit of using extraction ontologies is a quick development of a functional IE prototype, its smooth transition to deployed IE application and the possibility to leverage the use of each of the three extraction evidence types. Also, since extraction ontologies are typically developed by adapting suitable domain ontologies and the ontology remains in center of the extraction process, the work related to the conversion of extracted results back to a domain ontology or schema is minimized. The described approach is evaluated using several distinct real-world datasets.
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Ontologický přístup k integraci geografických dat
Linková, Zdeňka ; Nedbal, Radim
A key point in modern automated data processing is metadata semantics representation. Employing Semantic Web existing features - ontologies - is a promising option. Ontologies open a novel approach to knowledge representation. The paper presents a GIS (Geographic Information System) domain application illustrating ontological approach to data integration and data processing automation in the specific system. This VirGIS system is an integration system that works with spatio-temporal data. We start our study with developing the data representation based on common Semantic Web techniques and build a VirGIS ontology.
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Integrace schémat založená na ontologiích
Linková, Zdeňka
Data integration usually provides a unified global view over several data sources. A crucial part of the task is the establishment of the connection between the global view and the local sources. For this purpose, two basic mapping approaches have been proposed: GAV (Global As View) and LAV (Local As View). On the Semantic Web, there can be considered also an ontological approach. In this paper, data integration is solved using ontologies of the sources. To express relationships between the global view and local source schemas, an ontology for the integration system is built. Thus, a schema integration task is transformed to an ontology merging task.
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Integrační systém založený na ontologiích
Linková, Zdeňka
Integration has been an acknowledged problem for a long time. With the aim at combining data from different sources, data integration usually provides a unified global view over these data. A crucial part of the task is the establishment of the connection between the global view and the local sources. Two basic approaches have been proposed for this purpose: Global As View (GAV) and Local As View (LAV). With the Semantic Web and its data description means, there is also another possibility - to employ ontologies for the relationship description in an integration system.
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