Yoshifumi MASUNAGA, Department of Mathematics and Information Science, Professor

[ Japanese / English ]

The aim of Masunaga laboratory is to do research and development of advanced database systems for the new century. The research topics under investigation in Masunaga Laboratory include the development of the virtual world database system (VWDB), three-dimensional (3D) moving object database system, data mining, and others:

We have introduced the concept and preliminary design of the "Virtual World Database System (VWDB)." The VWDB is different from traditional database systems such as relational database systems in that both the real world and the objects in it are captured as possible as they are in the real world. Therefore, database users can see the database objects as if they exist in the real world and can therefore grasp, move, and drop these objects in the database as is allowed in the real world. The CSG (Constructive Solid Geometry) approach to CAD (Computer Aided Design) is adopted in the VWDB to represent virtual world objects. Virtual reality systems and an object-oriented database system are then integrated to realize the VWDB. In the VWDB, users interact with the database objects in a multimodal manner. The design of a MUI (Multimodal User Interface) is given in this paper based on automata theory. The VWDB is the extended and revised version of the Block-World Database System (BWDM) that we previously developed (The figure shown above is an snapshot of the BWDB).

We have investigated a new data model for the realization of a 3D moving object database system. In contrast to the traditional approach, it can deal with spatio-temporal characteristics of moving objects in the 3D space. A spatio-temporal sampling theory is introduced that enables a database system to store and manipulate all of the necessary spatio-temporal information about moving objects. The 3D moving object database consists of three kinds of relations: a set of primary relations, such as POSI, ORI, GRAD, and SHAPE, store all the essential spatio-temporal features of a single moving object; a set of built-in derived relations, such as DIR, SPEED, TRACK, DIST, MDIR, and TOPOL, store, for example, the moving direction of a single object (DIR) and the topological relation between two objects (TOPOL); and a set of user-defined relations such as BACK and FRONT with which one can issue a variety of spatio-temporal queries on moving objects. A domain relational calculus-based moving object query language named MOQL is investigated.

The data mining is a joint research work with the National Astronomical Observatory of Japan. It aims to develop an automated astronomical signal identification system, which is an expert system that can distinguish noise and very weak signals as much as possible that helps astronomers to discover new species. The international standard relational database language SQL will be expanded to support data mining functions for classification and clustering.

REFERENCES

  1. Y. Masunaga and C. Watanabe: The Virtual World Database System- Its Concept, Design, and Prototyping-, Advances in Multimedia and Databases for the New Century-A Swiss/Japanese Perspective-, World Scientific (to appear, 2000)
  2. Y. Mausnaga and N. Ukai: Toward a 3D Moving Object Data Model - A Preliminary Consideration -, Proc. of 1999 International Symposium on Database Applications in Non-Traditional Environments (DANTE'99), IEEE Computer Science Press (to appear, 2000)
  3. Y. Mausnaga, H. Kawashima, and Y. Mizuno: A Prototyping of the Block-World Database System (in Japanese), IPSJ Transactions on Databases, Vol. 40, No. SIG3(TOD1)（1999）
  4. Y. Masunaga: New Generation Database Technologies for Collaborative Work Support and Spatio-Temporal Data Management，IEICE Transactions on Information and Systems（1999）
  5. Y. Masunaga and Y. Arakawa: Realization of Japanese Voice Access to Relational Database Sytems (in Japanese)， Transactions of IPSJ， Vol. 39, No. 4（1998）
  6. Y. Masunaga: Re-examination of Allen's Interval-based Temporal Logic ，Transactions of IPSJ，Vol. 39, No. 4（1998）
  7. Y. Masunaga: The Block-World Data Model for a Collaborative Virtual Environment,　Proc. Second Intl. Conf. on Worldwide Computing and Its Applications (WWCA'98), Springer (1998)
  8. Y. Masunaga: A Unified Approach to Representation, Synchronization and Storage of Temporal Multimedia Objects based on Time Interval Logic, Proc. 5th Intl. Conf. on Database Systems for Advanced Applications (DASFAA '97), World Scientific (1997)
  9. Y. Mausnaga, K. Nonaka, and H. Kiyomitsu: An Implementation of Synchronized Playback Scheme of Temporal Multimedia Objects based on Time Interval Logic (in Japanese)，Transactions of IEICE D-I, Vol.J79-D-I, No.10 ( 1996)
  10. Y. Masunaga: An Object-Oriented Approach to Temporal Multimedia Data Modeling, IEICE Transactions on Information and Systems, Vol.E78-D, No.11 (1995)
  11. Y. Masunaga: Foundation of Relational Database -Data Model Issues- (Book in Japanese), Ohm-sha, (1990)
  12. Y. Masunaga: Introduction to Relational databases (Book in Japanese), Science-sha (1991)

KEY WORDS

Multimedia database system; Spatio-temporal database system; Virtual world database system (VWDB); Moving object database system; Data mining

ADDRESS

2-1-1, Otsuka, Bunkyo-ku, Tokyo, 112-8610, Japan.
E-mail:
masunaga@is.ocha.ac.jp
Phone:+81-3-5978-5707
Fax:+81-3-5978-5707

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