Studies on Cooperative Information Systems

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This research aims at realizing distributed cooperative work environments for integrating and utilizing various information resources distributed among networks. Themes of this research include pursuing cooperative interoperability of distributed heterogeneous multimedia information and modeling cooperative information systems by extending object-oriented model.In 1998, mechanisms for dynamic updating of environments are designed for a virtual office application system. Transaction in cooperative systemsare required more detailed control and flexibility than conventional transactions. A new method that realizes such tranactions has been developed. We also have exarnined trends in technologies related to data warehouse, made a submission about guidelines for the research community, developed a new method for view update that improves in efficiency of conventional solutions, and designed and implemented an action history view function on a cooperative hypermedia system.In 1999, the devel … More opment of a multimedia cooperative processing system that is a platform for development of application systems such as a distance education system and a virtual office system has proceeded, and feedback from users was obtained by experiments about usage. We also studied extension of interoperability in multimedia databases supporting personalization for each user and a model for multimedia information systems based on extension of view functions of object-oriented databases. The model was incorporated with the architecture of our cooperative hypermedia system. In addition to these, utilization of a data warehouse technology in cooperative systems and parallel processing for increasing efficiency and a guarantee of correctness in cooperative processing were studied.In 2000, we have integrated our research results about cooperative information systems, reorganized them as basic techniques for developing practical cooperative systems. First, a mechanism for management of transitions of working status in a cooperative hypermedia system was designed, implemented, and evaluated. It shows that the mechanism decreases a operating load of work managers and supports cooperative work that has complex working statuses. Secondly, we integrated action history view mechanisms into our education support system and used the system in practice. It became clear that the action history view mechanisms are useful in practical application such as education systems. We also studied methods for raising WWW cache hit-rate and proposed a new concept web-warehouse, which integrates WWW and data warehouse technologies and provides more advanced utilization of WWW data. Less