SENSOR NETWORK MANAGING APPARATUS AND METHOD THEREOF

• US 20100306189A1
• Filed: 08/21/2008
• Published: 12/02/2010
• Est. Priority Date: 11/29/2007
• Status: Active Grant

• Current Assignee: Electronics and Telecommunications Research Institute
• Original Assignee: Electronics and Telecommunications Research Institute
• Inventors: Park, Jong-Hyun, Kim, Min Soo, Lee, Yong Joon, Lee, Chung-ho
• Granted Patent: US 8,515,944 B2
• Time in Patent Office: Days
• US Class Current: 707/714
• CPC Class Codes: G06F 16/24544 Join order optimisation
• CPC Class Codes: H04L 41/12 Discovery or management of network topologies
• CPC Class Codes: H04L 67/125 involving control of end-device applications over a network
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

The present invention relates to a sensor network managing apparatus and a method thereof. The sensor network managing apparatus according to the present invention receives a query that includes a spatial join predicate for searching for target sensor nodes and a comparison predicate that is different for each sensor network, and generates query execution order information for searching for the target sensor nodes based on the spatial join predicate and the comparison predicate, wherein the spatial join predicate is related to a spatial location between sensor nodes respectively included in different sensor networks, and the comparison predicate are related to sensing values of sensor nodes of the sensor networks. In addition, the sensor node managing apparatus executes queries for the spatial join predicate and the comparison predicate on the plurality of sensor nodes on the basis of determined query execution order, and then extracts target sensor nodes as the query results. According to the present invention, an efficient method for searching for user-desired sensor nodes in more than two different sensor networks can be provided.

Claims

1. A sensor node managing apparatus that transmits/receives data through connection with more than two different sensor networks, each of which includes a plurality of sensor nodes, the sensor node managing apparatus comprising:

a query optimization unit receiving a query that includes a spatial join predicate for searching for target sensor nodes and a comparison predicate that is different for each sensor network, and

generating query execution order for searching for the target sensor nodes based on the received query, wherein the spatial join predicate is related to a spatial location between the sensor nodes respectively included in different sensor networks, and wherein the comparison predicate is related to sensing values of the sensor nodes from the respective sensor networks; and

a query execution unit executing the spatial join predicate and the comparison predicate on the more than two different sensor networks based on the query execution order received from the query optimization unit, and extracting the target sensor nodes by using a result of the execution.

2. The sensor node managing apparatus of claim 1, further comprising a spatial index unit storing location information of the sensor nodes respectively included in the more than two sensor networks,

wherein the query execution unit extracts sensor nodes that correspond to the spatial join predicate based on the location information stored in the spatial index unit.

3. The sensor node managing apparatus of claim 2, further comprising a query result storage unit storing selectivity information that includes sensor node extraction information of each sensor node network with respect to previous execution results of a previous spatial join predicate and a previous comparison predicate, which have been previously executed,

wherein, when selectivity information on the previous spatial join predicate and the previous comparison predicate is stored in the query result storage unit, the query optimization unit generates the query execution order based on the selectivity information stored in the query result storage unit.

4. The sensor node managing apparatus of claim 3, wherein the query optimization unit generates the query execution order for the comparison predicates to be executed on the more than two sensor networks based on the selectivity information of the previous spatial join predicate and the previous comparison operation predicate, after performing the spatial join predicate.

5. The sensor node managing apparatus of claim 4, wherein the target sensor node is at least more than two sensor nodes, each of which is included in a different sensor network.

6. The sensor node managing apparatus of claim 2, wherein the query execution unit executes the comparison predicate on each of the more than two sensor networks, and extracts sensor nodes that satisfy the comparison predicate for each of the sensor networks.

7. A sensor node managing method for managing more than two different sensor networks, each including a plurality of sensor nodes, the sensor node managing method comprising:

receiving a query that includes a spatial join predicate for searching target sensor nodes and a comparison predicate that is different for each sensor network, wherein the spatial join predicate is related to a spatial location between the sensor nodes, each included in a different sensor network, and wherein the comparison predicate is related to sensing values of the sensor nodes in each sensor network;

determining query execution order for searching target sensor nodes respectively included in the more than two different sensor networks on the basis of the spatial join predicate and the comparison predicate;

executing a query of the spatial join predicate and the comparison predicate for the plurality of sensor nodes on the basis of the determined query execution order; and

extracting the target sensor nodes as a query result of the executing of the query.

8. The sensor node managing method of claim 7, wherein the determining of the query execution order comprises:

determining whether selectivity information corresponding to the spatial join predicate and the comparison predicate is included in previous selectivity information of sensor nodes selected by a previous spatial join predicate and a previous comparison predicate that have been previously stored; and

determining query execution order for searching for target sensor nodes of the more than two different sensor networks on the basis of the corresponding selectivity information if the corresponding selectivity information exists.

9. The sensor node managing method of claim 8, further comprising randomly determining query execution order for the comparison predicate if the corresponding selectivity information does not exist.

10. The sensor node managing method of claim 8, wherein the executing of the query comprises:

extracting first candidate nodes of the spatial join predicate from among the plurality of sensor nodes based on stored location information of the plurality of sensor nodes;

executing a first comparison predicate on sensor nodes included in the first candidate nodes from among sensor nodes of a first sensor network based on the query execution order;

extracting second candidate nodes by executing the spatial join predicate on sensor nodes of a second sensor network, which correspond to the sensor nodes of the first sensor network, which have been selected by the first comparison predicate from the first candidate nodes; and

executing a second comparison predicate on the sensor nodes of the second sensor network among the second candidate nodes.

11. The sensor node managing method of claim 10, further comprising, after the extracting of the target sensor nodes, storing first selectivity information on an extraction ratio of the target sensor node for each of the more than two different sensor networks.