Query Processing In Wide Area Sensor Databases

Sensor network has become a newly hot and front research area. It is acombined subject that crosses with sensor technology, embedded computingtechnology, distributed information processing technology and communicationtechnology, etc. It has been a revolution of information sensing, collecting andprocessing. So more and more countries' military, academic and industries payhigh attentions to sensor network.In this paper, aiming at the query problems in sensor network, we make adeep research on query problems and deep nesting query problems in wide areasensor databases which is based on IrisNet. Firstly, according to thecharacteristics of deep nesting query techniques used in wide area sensordatabases, we analyze the problems of data overkill and low rate of datautilizations, and then we present bool-type deep nesting query technique, andanalyze the characteristics of this technique. This technique uses a method ofsending subqueries directly to correlative sites to evaluate the predicates toprocess the problems of bool-type deep nesting query.Secondly, according to the problems of inefficient of query and even can'tquery problems when using bool-type deep nesting query technique to processnon-bool-type deep nesting queries, we present non-bool-type deep nestingquery technique. This technique uses a method of adding additive informationto correlative sites to make these sites to be a linear list, then query all sites oneby one in the linear list to process non-bool-type deep nesting queries. And inorder to improve the performance of non-bool-type deep nesting queryprocessing, we introduce a method of grouping sites.At last, according to the characteristics of bool-type deep nesting queryand non-bool-type deep nesting query in processing bool-type deep nestingqueries and non-bool-type deep nesting queries, we present deep nestingqueries decomposing optimize arithmetic. This arithmetic decomposes a queryinto bool-type and non-bool-type subqueries, then respectively use bool-typedeep nesting query technique and non-bool-type deep nesting query techniqueto process these subqueries to improve the performance of system query.