Context is the information, which is created and obtained from the surrounding environment for the interaction between humans and computational services. A generic model is a key accessor to the context in any context-aware applications for ubiquitous computing. In the past decades, a number of context modeling techniques have been proposed e.g. markup scheme based, logic-based, graphical, and ontology-based. Since ontology in its nature is a promising tool to specify concepts and interrelations, it has been widely adopted in context modeling. However, in the rapid changing environments, semantics may vary according to the time factors and dynamic group of users. In this paper, we propose an ontology-based context model with temporal vector space in order to complement this deficiency.

A comprehensive video retrieval system should be able to accommodate and utilize various (complementary) description data in facilitating effective retrieval. We advocate a hybrid retrieval approach by integrating a query-based (database) mechanism with content-based retrieval (CBR) functions. We describe the VideoMAP/sup +/ architecture, discuss issues related to developing such a comprehensive video database management system, and its specific language mechanism (CAROL/ST with CBR) which provides an improved expressive power than pure query-based or CBR methods currently offer. We also describe an experimental prototype being developed based on a commercial object-oriented toolkit using VC++ and Java.

Videos are multi-faceted objects which can have different kinds of information descriptions. A comprehensive video retrieval system should be able to accommodate and utilize such various (complementary) description data in facilitating effective retrieval. In this paper, we present a hybrid approach by integrating a query-based (database) mechanism with content-based retrieval (CBR) functions. We describe the VideoMAP + architecture and its specific language mechanism (CAROL/ST with CBR) which provides an improved expressive power than what pure query-based or CBR methods currently offer. An experimental prototype is being developed using a commercial object-oriented toolkit on a PC platform.

The authors present a Web based architecture of a spatio-temporal video data management system, which can accommodate a wide range of activities by various types of users. Besides the support of basic concurrency control for video editing by multiple users, the system provides various kinds of profiles containing knowledge information and activity models which are useful for annotating abstracted information into video data and for processing video queries. We also describe the user interface facilities from the perspective of sample user interactions. This system is being built based on our earlier work of developing a comprehensive video data management system using extended object oriented concepts and techniques.