We introduce the natural class SP 2 containing those languages which may be expressed in terms of two symmetric quanti ers. This class lies between P 2 and P 2 P 2 and naturall...
Estimating the cardinality (i.e. number of distinct elements) of an arbitrary set expression defined over multiple distributed streams is one of the most fundamental queries of in...
Reverse skyline queries over uncertain databases have many important applications such as sensor data monitoring and business planning. Due to the existence of uncertainty in many...
—Recently, many new applications, such as sensor data monitoring and mobile device tracking, raise up the issue of uncertain data management. Compared to “certain” data, the ...
We describe the design and implementation of a system for logic-based multimedia retrieval. As highlevel logic for retrieval of hypermedia documents, we have developed a probabilis...