Yahiko Kambayashi

Database Studies and the Infrastructure of the Knowledge Society

The major purpose of database studies is to determine how to organize a large amount of data to be used by various software packages and users. By sharing data, these software packages and people can communicate with each other. Previous inventions of knowledge sharing technologies such as printing and mass-communication have changed the world completely. We believe that the new way of sharing knowledge realized by a combination of database technology and World Wide Web usage will also change this world drastically. In this article we will discuss some of our recent results on the use of database technology and a project in the Graduate School of Informatics, related to the future knowledge society.

The Web can be regarded as a great source of knowledge, with the amount of data it contains doubling approximately every six months. Hence it is very important to develop methods to find useful knowledge within the contents of the Web. We have developed a graph-base solution referred to as a contents graph that can represent the contents of any part of the Web. Since Web pages with similar contents will have a similar contents graph, such graphs can be used for similarity-based retrieval. Compared with conventional searches based on the specification of multiple keywords, we can get better results due to the existence of word relationships represented by the edges of the graph.

By generating contents graphs for sites containing news items, important topics and their relationships can be identified. Using archived news data, it is relatively easy to determine the transition of important topics. Furthermore, differences in the importance of certain topics to different countries can be observed by comparing the graphs of their news sites. In order to extract useful knowledge it is essential to identify Web pages having certain specified characteristics. Such Web page characterization can be realized by contents graphs.


Integrated user interface of Kyoto SEARCH (From left, city map, location map, a partial graph for semantic navigation. Bottom, a list of related URL's)

As another example, by accumulating data from the Web, we may be able to get data on how people perceive a city. We have developed methods to identify and characterize items referred to as land marks. For each location we can obtain characterizing information for that location. This information is used by a Geographic Information System (GIS) called Kyoto SEARCH. It has an integrated user interface consisting of a contents graph for semantic navigation, a map, and corresponding URLs. A version of the system is also used in Korea.

Although there is a large amount of data on the Web, only a small percentages of it is used frequently. These Web pages are called hot spots. An important problem with hot spots is their dynamically changing nature. As the speed of data increase on the Web is much faster than that of conventional communication lines, it is important to develop technology for efficient data retrieval. One of the more promising technologies to achieve this is called Web cache, which operates by storing frequently used data near the place of usage. By considering the characteristics of Web data we have developed a generalized Web cache system called Web Warehouse. It has proved to be a good system in improving Web efficiency.

Information retrieval discussed above is a basis for knowledge sharing. The technique can be applied to a variety of areas including collaboration support. People in far apart locations can work together via the Internet. By storing all the operations in a database, the nature of the work can be analyzed. Furthermore, collaboration between users working at different times is possible. In a real meeting, all information is equally shared by all participants. In a distributed meeting, we can define security levels for shared documents so that some documents can be used only by authorized users. We have developed a system called VIEW Media to realize an advanced distributed collaboration environment. Webbased training is one of the many promising applications for collaboration support systems. A system called VIEW Classroom has been developed, versions of which are actually used at a high school and a university in Kyoto.

In the Graduate School of Informatics we have a 21C-COE project called "Informatics Research Center for the Development of a Knowledge Society Infrastructure". The knowledge society is a fundamental concept for the future where various types of information scattered across the ubiquitous Internet are transformed and presented as easily understandable knowledge. People and social systems share and utilize this knowledge, and new information resulting from subsequent understanding is further circulated as new knowledge.

This program promotes research on:

  1. Versatile deployment of intelligent information media (media processing, artificial intelligence and related areas);
  2. Information creation and circulation infrastructure (database, Web and related research);
  3. Social information systems as applications of the above research (e-commerce, education, medical informatics and other applications).

Besides research and education we also encourage activities of international collaboration and social interaction. We have overseas offices in Thailand, China and the U.S. At these offices are planned environment research collaboration with Thai organizations, bases of computer science research with the Chinese Academy of Sciences, and Web and database research with Silicon Valley companies.


The poster of
ALAN-K project

As a form of social interaction we have several projects within Kyoto City. The Kyoto-One project is a plan to develop a unified network covering Kyoto by connecting various existing networks. In the ALAN-K (Advanced LeArning Network in Kyoto) project, the use of computers to help the creativity of young people is emphasized. This project is supported by Dr. Alan Kay, who invented the concept of personal computers. Presently two primary schools, one junior high school and two senior high schools are participating the project.


ALAN-K workshop at Horikawa high school. Dr. Alan Kay (first from right on second row) with primary school children.


A meeting with students. Prof. Kambayashi is also actively involved in developing the professional capabilities of young people. He is currently involved in a project that dispatches students to Silicon Valley. He feels that in his field it is essential to have experience of the American culture of competitiveness.


The Kambayashi Lab. The students working under the professor come from a variety of backgrounds. Some are graduates of the Faculty of Engineering and some come from the Faculty of Economics. Others have been working or are international students.

Photo of Kambayashi

Yahiko Kambayashi

Born in 1943.
Graduate of the doctoral program, Graduate School of Engineering, Kyoto University
Ph.D., Kyoto University
Professor, Graduate School of Infomatics, Kyoto University
URL http://www.db.soc.i.kyoto-u.ac.jp/usr/yahiko/yahiko-e.html (External Link)

"It is no good if you are not sure of what to answer when asked 'what and why are you going to study?' I think that having a dream is the most important thing."

With the application within society of the fruits of research in mind, Prof. Kambayashi pursues his academic work while constantly thinking about how best to accumulate knowledge and ensure that it is reused widely. He is also actively involved in collaborative work with partners outside the university. At present he is engaged in a cooperative effort involving the local community, working together with nearby high schools to develop a study system for mathematics. Another current endeavor that Prof. Kambayashi is enamored of is the project in collaboration with Alan Kay. The project, in which they are currently involved in earnest, aims to foster creativity by giving children the opportunity to experience programming in a manner similar to making things out of Lego pieces. Prof. Kambayashi aims to tackle real problems facing society from the distinctive viewpoint of an academic researcher of computer systems. His smiling countenance expresses his strong faith in his work and his kindness toward other human beings.