Der Lehrstuhl Datenbank- und Informationssysteme der Universität Rostock

Im Jahr 2014 feierte der Lehrstuhl Datenbank- und Informationssysteme (LS DBIS) an der Universität Rostock sein zwanzigjähriges Bestehen. Zur Jubiläumsveranstaltung mit ehemaligen und aktuellen Studenten, Mitarbeitern, Kollegen und Kooperationspartnern wurde diverses Material aus 20 Jahren aufbereitet. In diesem Beitrag soll daraus ein Rückblick auf 20 Jahre Forschung und Lehre im Bereich Datenbank- und Informationssysteme sowie ein Ein- und Ausblick auf aktuelle Forschungsarbeiten gegeben werden

Nomothesi@ api - reengineering the electronic platform

Ο στόχος αυτής της εργασίας, είναι να συμβάλει στον τομέα της αναπαράστασης νομικής γνώσης και στην ενσωμάτωση αυτής στην περιοχή των ανοιχτών δεδομένων στην Ελλάδα, τόσο από τεχνολογική σκοπιά, όσο και από άποψη διαφάνειας. Η Νομοθεσί@, είναι μια πλατφόρμα που σκοπό έχει να δώσει πρόσβαση στην ελληνική νομοθεσία, με τη χρήση ενός νομικού XML/RDF προτύπου και με διασυνδεδεμένα δεδομένα (linked data). Αυτή η νέα έκδοση της Νομοθεσίας προτείνει την αντικατάσταση του προηγούμενου προτύπου XML για τα ελληνικά νομικά έγγραφα για ένα νέο RDF, μια νέα Spring MVC αρχιτεκτονική και την παροχή πολλών REST υπηρεσιών όπως αυτή ενός SPARQL Endpoint. Η σύνδεση δεδομένων αφορά τη διασύνδεση και την ανοιχτή δημοσίευση ελληνικών δημόσιων δεδομένων και των νομοθετικών δεδομένων κατά μήκος της Ευρωπαϊκής Ένωσης, με σκοπό την ενίσχυση της ηλεκτρονικής διακυβέρνησης. Πάνω σε αυτές τις αρχές, προσπαθήσαμε να επεκτείνουμετη Νομοθεσί@ με ένα ενοποιημένο RDF Σχήμα δεδομένων, προκειμένου να δημιουργηθεί ένα RESTful API για να αξιοποιήσει ολόκληρη την πολύτιμη σημασιολογική πληροφορία που έχει να προσφέρει η ελληνική νομοθεσία και να ενθαρρύνει περαιτέρω και πιο πολύπλοκα έργα που βασίζονται στον τομέα του διαδικτύου για την αναζήτηση και την περιήγηση της νομοθεσίας.The objective of this thesis is to contribute in legal knowledge’s representation and its integration in the area of Open Data in Greece, both from a technological perspective and in terms of transparency. Nomothesi@, is a platform to provide access to Greek Legislation, by means of a legal XML/RDF syntax and linked data. This new version of Nomethesi@ proposes the replacement of the previous XML standard for Greek legal documents to a new RDF one, a new Spring MVC architecture and many REST services such as a SPARQL Endpoint. Linking data is about interlinking and publishing openly Greek public data and legislative data across EU in order to enhance E-Government. On these fundamentals, we tried to expand Nomothesi@ with a unified RDF Schema, in order to create a RESTful API to serve all the precious semantic information Greek Legislation has to offer and to encourage further and more complex projects based on web services for searching and browsing legislation

n-Gram-based text compression

We propose an efficient method for compressing Vietnamese text using n-gram dictionaries. It has a significant compression ratio in comparison with those of state-of-the-art methods on the same dataset. Given a text, first, the proposed method splits it into n-grams and then encodes them based on n-gram dictionaries. In the encoding phase, we use a sliding window with a size that ranges from bigram to five grams to obtain the best encoding stream. Each n-gram is encoded by two to four bytes accordingly based on its corresponding n-gram dictionary. We collected 2.5 GB text corpus from some Vietnamese news agencies to build n-gram dictionaries from unigram to five grams and achieve dictionaries with a size of 12 GB in total. In order to evaluate our method, we collected a testing set of 10 different text files with different sizes. The experimental results indicate that our method achieves compression ratio around 90% and outperforms state-of-the-art methods.Web of Scienceart. no. 948364

MEASURING APPLICATION DOMAIN KNOWLEDGE: RESULTS FROM A PRELIMINARY EXPERIMENT

Conceptual models are used in IS development for capturing and specifying requirements. However, the mere understanding of the syntax or semantics of a modeling language is not the most crucial factor. More relevant is pragmatic knowledge about the application domain. The problem that this paper addresses is how one can verify that a shared understanding of the application domain exists. In our study we show that domain-specific languages are an indicator for separating novices from experts in a given application domain. Novices and experts can be distinguished based on the domain-specific language they use. We demonstrate that these different language communities can be observed empirically by employing latent semantic analysis (LSA) as an instrument and by measuring semantic similarity. The separation of groups using LSA is also possible if the terminology, the application domain, or the expert-layperson-status of the examined group are unknown. Therefore the separation based on domain-specific languages is independent of the domain under consideration or the prior knowledge of the researcher. This provides a useful measurement instrument for studying the role of application domain knowledge in future research

CRIS-IR 2006

The recognition of entities and their relationships in document collections is an important step towards the discovery of latent knowledge as well as to support knowledge management applications. The challenge lies on how to extract and correlate entities, aiming to answer key knowledge management questions, such as; who works with whom, on which projects, with which customers and on what research areas. The present work proposes a knowledge mining approach supported by information retrieval and text mining tasks in which its core is based on the correlation of textual elements through the LRD (Latent Relation Discovery) method. Our experiments show that LRD outperform better than other correlation methods. Also, we present an application in order to demonstrate the approach over knowledge management scenarios.Fundação para a Ciência e a Tecnologia (FCT) Denmark's Electronic Research Librar

Visibility in Information Spaces and in Geographic Environments. Post-Proceedings of the KI'11 Workshop (October 4th, 2011, TU Berlin, Germany)

In the post-proceedings of the Workshop "Visibility in Information Spaces and in Geographic Environments" a selection of research papers is presented where the topic of visibility is addressed in different contexts. Visibility governs information selection in geographic environments as well as in information spaces and in cognition. The users of social media navigate in information spaces and at the same time, as embodied agents, they move in geographic environments. Both activities follow a similar type of information economy in which decisions by individuals or groups require a highly selective filtering to avoid information overload. In this context, visibility refers to the fact that in social processes some actors, topics or places are more salient than others. Formal notions of visibility include the centrality measures from social network analysis or the plethora of web page ranking methods. Recently, comparable approaches have been proposed to analyse activities in geographic environments: Place Rank, for instance, describes the social visibility of urban places based on the temporal sequence of tourist visit patterns. The workshop aimed to bring together researchers from AI, Geographic Information Science, Cognitive Science, and other disciplines who are interested in understanding how the different forms of visibility in information spaces and geographic environments relate to one another and how the results from basic research can be used to improve spatial search engines, geo-recommender systems or location-based social networks

30th International Conference on Information Modelling and Knowledge Bases

Information modelling is becoming more and more important topic for researchers, designers, and users of information systems. The amount and complexity of information itself, the number of abstraction levels of information, and the size of databases and knowledge bases are continuously growing. Conceptual modelling is one of the sub-areas of information modelling. The aim of this conference is to bring together experts from different areas of computer science and other disciplines, who have a common interest in understanding and solving problems on information modelling and knowledge bases, as well as applying the results of research to practice. We also aim to recognize and study new areas on modelling and knowledge bases to which more attention should be paid. Therefore philosophy and logic, cognitive science, knowledge management, linguistics and management science are relevant areas, too. In the conference, there will be three categories of presentations, i.e. full papers, short papers and position papers

Proceedings of the 9th International Workshop on Information Retrieval on Current Research Information Systems

The recognition of entities and their relationships in document collections is an important step towards the discovery of latent knowledge as well as to support knowledge management applications. The challenge lies on how to extract and correlate entities, aiming to answer key knowledge management questions, such as; who works with whom, on which projects, with which customers and on what research areas. The present work proposes a knowledge mining approach supported by information retrieval and text mining tasks in which its core is based on the correlation of textual elements through the LRD (Latent Relation Discovery) method. Our experiments show that LRD outperform better than other correlation methods. Also, we present an application in order to demonstrate the approach over knowledge management scenarios

24th International Conference on Information Modelling and Knowledge Bases

In the last three decades information modelling and knowledge bases have become essentially important subjects not only in academic communities related to information systems and computer science but also in the business area where information technology is applied. The series of European – Japanese Conference on Information Modelling and Knowledge Bases (EJC) originally started as a co-operation initiative between Japan and Finland in 1982. The practical operations were then organised by professor Ohsuga in Japan and professors Hannu Kangassalo and Hannu Jaakkola in Finland (Nordic countries). Geographical scope has expanded to cover Europe and also other countries. Workshop characteristic - discussion, enough time for presentations and limited number of participants (50) / papers (30) - is typical for the conference. Suggested topics include, but are not limited to: 1. Conceptual modelling: Modelling and specification languages; Domain-specific conceptual modelling; Concepts, concept theories and ontologies; Conceptual modelling of large and heterogeneous systems; Conceptual modelling of spatial, temporal and biological data; Methods for developing, validating and communicating conceptual models. 2. Knowledge and information modelling and discovery: Knowledge discovery, knowledge representation and knowledge management; Advanced data mining and analysis methods; Conceptions of knowledge and information; Modelling information requirements; Intelligent information systems; Information recognition and information modelling. 3. Linguistic modelling: Models of HCI; Information delivery to users; Intelligent informal querying; Linguistic foundation of information and knowledge; Fuzzy linguistic models; Philosophical and linguistic foundations of conceptual models. 4. Cross-cultural communication and social computing: Cross-cultural support systems; Integration, evolution and migration of systems; Collaborative societies; Multicultural web-based software systems; Intercultural collaboration and support systems; Social computing, behavioral modeling and prediction. 5. Environmental modelling and engineering: Environmental information systems (architecture); Spatial, temporal and observational information systems; Large-scale environmental systems; Collaborative knowledge base systems; Agent concepts and conceptualisation; Hazard prediction, prevention and steering systems. 6. Multimedia data modelling and systems: Modelling multimedia information and knowledge; Contentbased multimedia data management; Content-based multimedia retrieval; Privacy and context enhancing technologies; Semantics and pragmatics of multimedia data; Metadata for multimedia information systems. Overall we received 56 submissions. After careful evaluation, 16 papers have been selected as long paper, 17 papers as short papers, 5 papers as position papers, and 3 papers for presentation of perspective challenges. We thank all colleagues for their support of this issue of the EJC conference, especially the program committee, the organising committee, and the programme coordination team. The long and the short papers presented in the conference are revised after the conference and published in the Series of “Frontiers in Artificial Intelligence” by IOS Press (Amsterdam). The books “Information Modelling and Knowledge Bases” are edited by the Editing Committee of the conference. We believe that the conference will be productive and fruitful in the advance of research and application of information modelling and knowledge bases. Bernhard Thalheim Hannu Jaakkola Yasushi Kiyok