Sensor data fusion imposes a number of novel requirements on query languages and query processing techniques. A spatial/temporal query language called /spl Sigma/QL has been proposed to support the retrieval and fusion of multimedia information from multiple sources and databases. In this paper we investigate fusion techniques, multimedia data transformations and /spl Sigma/QL query processing techniques for sensor data fusion. Fusion techniques including fusion by the merge operation, the detection of moving objects, and the incorporation of belief values, have been developed. An experimental prototype has been implemented and tested to demonstrate the feasibility of these techniques.

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Querying distributed multimedia databases and data sources for sensor data fusion

To support the retrieval and fusion of multimedia information from multiple real-time sources and databases, a novel approach for sensor-based query processing is described. The sensor dependency tree is used to facilitate query optimization. Through query refinement one or more sensor may provide feedback information to the other sensors. The approach is also applicable to evolutionary queries that change in time and/or space, depending upon the temporal/spatial coordinates of the query originator.

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Multi-sensor Information Fusion by Query Refinement

The sentient map is a new paradigm for visual information retrieval. It enables the user to view data as maps, so that gestures, more specifically c-gestures, can be used for the interaction between the user and the multimedia information system. Different c-gestures are then dynamically transformed into spatial/temporal queries, or ?-queries, for multimedia information sources and databases. An e-learning environment involving many academic institutions serves as a test bed to evaluate this approach.

The Sentient Map

To support the retrieval and fusion of multimedia information from multiple sources and databases, a spatial/temporal query language called ?QL was proposed. ?QL is based upon the ?-operator sequence and in practice expressible in SQL-like syntax. ?QL allows a user to specify powerful spatial/temporal queries for both multimedia data sources and multimedia databases, eliminating the need to write different queries for each. In this paper, we illustrate this approach by query processing examples for information fusion applications.

Spatial/Temporal Query Processing for Information Fusion Applications

The main goal of this work is to provide an advanced visual environment where users that are not skilled for what concerns the computer science domain may compose queries related to those geographical phenomena for which the third dimension is a relevant feature. Visual queries are composed in a 3D environment accessible from the web where the users manipulate geographical objects, called 3D geometaphors. The geometaphors represent the operands of an underlying algebra characterized by a set of topological, directional and metrical operators; such operators are expressed in the query environment in terms of visual relationships between the geographical objects. The introduction of the third dimension for querying the geographical databases has challenged the authors with a number of important issues related to the area of visualization, navigation and object manipulation. According to the principles of usability engineering, the authors have built different prototypes based on a client-server architecture that have been iteratively evaluated by experts and final users in order to discover drawbacks and to improve the quality of the proposal. The result is a coordinated user-friendly 3D visual metaphor for querying GIS on the web, where all the elements needed for composing a query have a visual, easy to understand, counterpart.

A usability-driven approach to the development of a 3D web-GIS environment

To support the retrieval, fusion and discovery of multimedia information, a spatial/temporal query language for multiple data sources is needed. In this paper we describe a spatial/temporal query language, the ∑QL, which is based upon the σ-operator sequence and in practice expressible in an SQL-like syntax. The general σ-operator and temporal σ-operator are explained, and applications of the σ-query language to vertical/horizontal reasoning and hypermapped virtual world are discussed.

Erland Jungert

Papers

A spatial/temporal query language for multiple data sources in a heterogeneous information system environment