Integrating periodic data sequences based on freshness and synchronousness

Presents frameworks for acquiring data from servers that broadcast data periodically at constant intervals. We assume that different servers broadcast data for different periods at different intervals, and our focus is on choosing a fresh and synchronous combination of data, each obtained from a different server. We define an evaluation function to determine which data combination to use, taking into account both the freshness and the synchronousness of the data. Then we present a data acquisition framework for consecutive queries. For efficiency, the points of time that give the optimum data combinations are pre-computed. We show the pre-computation results can also be used for interactive queries which enable application programs to set limits on the data synchronousness and response time.