Dynamic on-demand updating of data in real-time database systems

The amount of data handled by real-time and embedded applications is increasing. Also, applications normally have constraints with respect to freshness and timeliness of the data they use, i.e., results must be produced within a deadline using accurate data. This calls for data-centric approaches when designing embedded systems, where data and its meta-information (temporal correctness requirements etc) are stored centrally. The focus of this paper is on maintaining data freshness in soft real-time embedded systems and the target application is vehicular systems. The contributions of this paper are three-fold. We (i) define a specific notion of data freshness by adopting data similarity in the value-domain of data items using data validity bounds that express required accuracy of data, (ii) present a scheme for managing updates in response to changes in the data items; and (iii) present a new on-demand scheduling algorithm, On-Demand Depth-First Traversal denoted ODDFT, for enforcin...

• Type: Conference
• Year: 2004
• Where: SAC
• Authors: Thomas Gustafsson, Jörgen Hansson
• Keywords: Applied Computing, Data Freshness, Data Items, Embedded Systems, SAC 2004