A semantic solution for data integration in mixed sensor networks
چکیده
The number of sensors deployed for a myriad of applications is expected to increase dramatically in the coming few years. This is spurred by advances in wireless communications and the growing interest in wireless sensor networks. This growth will not only simplify the access to information sources but also will motivate the creation of numerous new ones. Paradoxically, this growth will make the task of getting meaningful information obtained from disparate sensor nodes not a trivial one. On the one hand, traffic overheads and the increased probabilities of hardware failures make it very difficult to maintain an always-on, ubiquitous service. On the other hand, the heterogeneity of the sensor nodes makes finding, extracting, and aggregating data at the processing elements and sink nodes much harder. These two issues (in addition to distribution, dynamicity, accuracy, and reliability issues) impose the need for a more efficient and reliable techniques for information integration of data collected from sensor nodes. In this paper, we first address the issues related to data integration in wireless sensor networks with respect to heterogeneity, dynamicity, and distribution at both the technology and application levels. Second, we present and discuss a query processing algorithm which make use of the semantic knowledge about sensor networks expressed in the form of integrity constraints to reduce network traffic overheads, improve scalability and extensibility of wireless networks and increase the stability and reliability of networks against hardware and software failures. Third, we discuss a scenario of what we believe a uniform interface to data collected from sensor nodes that will map sensor specific data to the global information source based on a context exported by the data integration system