This paper proposes a framework based on a new architecture that allows distributed smartcards to interact with one another as well as with application programs on their hosts. Since these interactions are handled distribution-transparently through message dispatching agents deployed on each host, the smartcards can autonomously conduct distributed protocols without turning to off-card application programs. The proposed framework thus reduces the complexity of application programs and makes it easier to develop smartcard-based services that offer a high level of functionality. The feasibility of the framework is evaluated and confirmed by implementing a smartcard-based optimistic fair trading protocol for electronic vouchers on this framework.

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This paper describes a Multimedia Multi-User Dungeon System for the Digital Museum.The Digital Museum is a computer aided museum. In the Digital Museum, we can not only see many actual exhibits as the same as usual museums, but access multimedia databases to acquire more information with kiosk terminals. As the interface of multimedia databases, we developed the Multimedia Multi-User Dungeon (MMMUD) System.The MMMUD System is a shared virtual environment system designed with client-server architecture. A MMMUD browser renders images of the virtual environment from the player's viewpoint. We can explore the virtual environment freely and can access materials in the virtual environment by applying tools to them. The MMMUD system provides realtime multi-user interactions. We can see motion of other players while we are exploring the virtual environment, and we can see other user's tool sessions while we are applying tools to exhibits. In addition, each MMMUD browser has a microphone and users in the same room or browsing the same exhibit can talk with others. Moreover, we can import chromakey video images in the virtual environment for explanation of materials and guidance of the virtual museum.