large number of sensor nodes are connected through a multi-hop wireless network and each node keeps sensor data.
A query optimiser is located on the gateway node to generate distributed query processing plans after receiving queries from outside.
Expression in Cougar
it is proposed to divide the model of the sensor data into a user expression and an internal expression.
First, the user expression is a query, and an Abstract Data Type (ADT) is defined for the sensor, and it proposes the query language of the syntax similar to SQL. For instance, query processing for a monitor can be described as follows.
SINA aims to achieve scalability and low power consumption in sensor networks.
SINA consists of the following function components.
Hierarchical clustering: The sensor nodes contain the function to build the hierarchical cluster structure dynamically.
Attribute based Name management: The sensor node is managed by the name based on the attribute but note ID. For instance, [type = temperature, location = NE, temperature = 103] means all the sensors indicating 103 degrees in the northeast division.
Position management: The position of the sensor node is measured, and managed by GPS etc.