Database Group


Hiroyuki Kitagawa, Professor

Hiroyuki Kitagawa received the BSc degree in physics and the MSc and DrSc degrees in computer science, all from the University of Tokyo.  He is currently a full professor at Graduate School of Systems and Information Engineering and at Center for Computational Sciences, University of Tsukuba. His research interests include integration of information sources, data mining, stream-based ubiquitous data management, web data management, XML, and scientific databases. He is a fellow of the IPSJ and the IEICE, and a Trustee of the DBSJ.

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About our group

The amount of information being produced by human activities is growing rapidly, and such an overwhelming situation makes the management and utilization of massive information difficult and challenging.  The database group in the computational informatics division is in charge of research and development in the field of data engineering. In particular, we have been engaging in the following research topics: infrastructure for integrating heterogeneous databases and various information sources, data mining and knowledge discovery technologies to discover knowledge and rules from massive data, XML-related technologies to deal with various data uniformly in the Internet environment. Additionally, we also have engaged in application studies in cooperation with other research groups in CCS.

Fig.1: Infrastructure for information integration.

Research topics

Infrastructure for Information Integration: We have been investigating infrastructures, systems, and applications, which enable us to integrate heterogeneous and distributed databases and information sources. We developed StreamSpinner, which is a stream processing engine capable of integrating data streams like sensor data, as well as conventional data sources like relational databases. Other related research topics includedistributed stream processing, a high-availability scheme, and stream processing for uncertain data.

Data Mining and Knowledge Discovery: We have been working on various data mining and knowledge discovery techniques to extract valuable knowledge from massive information resources, such as databases and the Web. In particular, our recent research focus is on outlier detection and web and social media mining.

XML and Web Programming: XML is a meta-language for data representation, and has been widely used as a standardized data format for data interoperability in network environments. As a consequence, the amount of data generated and/or stored in the form of XML is explosively increasing, and this seems to be the trend for the foreseeable future. For this, we have been addressing diverse issues aiming at developing efficient and effective means for the management of massive XML resources. We are particularly interested in OLAP (Online Analytical Processing) for XML, faceted-navigation for XML, and parallel Holistic Twig Joins.

Collaboration with Other Research Groups

GPV/JMA Archive:As a collaborative work with the global environmental science group in CCS, we have been developing, maintaining, and managing GPV/JMA Archive ( Its objective is to store meteorological data provided by the Japan Meteorological Agency (JMA), and make the stored data publicly available to external users.

ILDG / JLDG:The International Lattice Data Grid (ILDG) is an international project to facilitate sharing and exchange of lattice QCD gauge configurations among organizations in collaboration using a grid infrastructure. Japan Lattice Data Grid (JLDG) is a regional grid of ILDG in Japan. Our research group takes part in the activities in ILDG and JLDG, and has developed a search interface for QCDml ensemble XML metadata based on faceted-navigation for XML.

Fig.2: Faceted-navigation interface for QCDml ensemble metadata.

Web sites

KITAGAWA Data Engineering