Ontology learning and question answering (qa) systems

Başkurt, Meltem
Ontology Learning requires a deep specialization on Semantic Web, Knowledge Representation, Search Engines, Inductive Learning, Natural Language Processing, Information Storage, Extraction and Retrieval. Huge amount of domain specific, unstructured on-line data needs to be expressed in machine understandable and semantically searchable format. Currently users are often forced to search manually in the results returned by the keyword-based search services. They also want to use their native languages to express what they search. In this thesis we developed an ontology based question answering system that satisfies these needs by the research outputs of the areas stated above. The system allows users to enter a question about a restricted domain by means of natural language and returns exact answer of the questions. A set of questions are collected from the users in the domain. In addition to questions, their corresponding question templates were generated on the basis of the domain ontology. When the user asks a question and hits the search button, system chooses the suitable question template and builds a SPARQL query according to this template. System is also capable of answering questions required inference by using generic inference rules defined at a rule file. Our evaluation with ten users shows that the sytem is extremely simple to use without any training resulting in very good query performance.


Ontology on Semantic Web
Doğandağ, Semra; Alpaslan, Ferda Nur (IOS PRESS, NIEUWE HEMWEG 6B, 1013 BG AMSTERDAM, NETHERLANDS, 2007-10-24)
OWL (Web Ontology Language) is a markup ontology language based on Description Logics (DL). It is about to become standard ontology language on the web, therefore different communities try to export their ontologies to OWL. Although OWL is highly expressive, it is not always easy to map a formalism to another one. There are some important conceptual modeling problems that should be revisited by OWL. In this paper we have chosen MPEG-7 as an example meta-language. MPEG-7 is written using XML-Schema. We discu...
Durak, Umut; Oğuztüzün, Mehmet Halit S.; Ider, S. Kemal (World Scientific Pub Co Pte Lt, 2009-12-01)
We apply an ontology based knowledge and software reuse methodology adhering to domain engineering principles. Our domain is trajectory simulation. A trajectory simulation is a piece of software to calculate the flight path and other parameters of a munition, such as its orientation and angular rates, from launch to impact. Trajectory Simulation ONTology (TSONT) has been constructed as part of the domain analysis. Object oriented and function oriented reuse infrastructures have been built based upon TSONT f...
Computational representation of protein sequences for homology detection and classification
Oğul, Hasan; Mumcuoğlu, Ünal Erkan; Department of Information Systems (2006)
Machine learning techniques have been widely used for classification problems in computational biology. They require that the input must be a collection of fixedlength feature vectors. Since proteins are of varying lengths, there is a need for a means of representing protein sequences by a fixed-number of features. This thesis introduces three novel methods for this purpose: n-peptide compositions with reduced alphabets, pairwise similarity scores by maximal unique matches, and pairwise similarity scores by...
Natural language query processing in ontology based multimedia databases
Aygül, Filiz Alaca; Çiçekli, Fehime Nihan; Department of Computer Engineering (2010)
In this thesis a natural language query interface is developed for semantic and spatio-temporal querying of MPEG-7 based domain ontologies. The underlying ontology is created by attaching domain ontologies to the core Rhizomik MPEG-7 ontology. The user can pose concept, complex concept (objects connected with an “AND” or “OR” connector), spatial (left, right . . . ), temporal (before, after, at least 10 minutes before, 5 minutes after . . . ), object trajectory and directional trajectory (east, west, southe...
Ontology evaluation: An example of delay analysis
Bilgin, Gozde; Dikmen Toker, İrem; Birgönül, Mustafa Talat (2014-06-24)
Ontologies have a place in knowledge sharing with their ability to capture real world information in a machine readable environment. Their application varies from any approach structured on ontological commitment to meta -level ontologies serving for variety of purposes. This variety continues also in methodologies for constructing the ontologies. There are wide range of ontologies differing in size and complexity that are created with different design criteria. The main point with the ontologies is their s...
Citation Formats
M. Başkurt, “Ontology learning and question answering (qa) systems,” M.S. - Master of Science, Middle East Technical University, 2010.