MOBILE MIDDLEWARE SUPPORTING CONTEXT MONITORING AND CONTEXT MONITORING METHOD USING THE SAME

• US 20080248789A1
• Filed: 03/26/2008
• Published: 10/09/2008
• Est. Priority Date: 04/06/2007
• Status: Active Grant

• Current Assignee: Korea Advanced Institute of Science and Technology
• Original Assignee: Korea Advanced Institute of Science and Technology
• Inventors: Lee, Jin-Won, Park, Soun-Eil, Kang, Seung-Woo, Lee, Hyon-Ik, Song, June-Wha, Park, Tai-Woo, Jang, Hyuk-Jae, Son, Yong-Joon
• Granted Patent: US 8,812,577 B2
• Time in Patent Office: Days
• US Class Current: 455/414.3
• CPC Class Codes: H04W 52/0267 by controlling user interface components
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

Disclosed herein is mobile middleware, a context monitoring method, a context-aware system, and a context-aware service provision method, which support energy-efficient context monitoring. The mobile middleware receives a request for a CMQ from context-aware application programs, receives sensor data from sensors, monitors whether the CMQ is satisfied, and transmits an event to the context-aware application programs according to results of the monitoring. In this case, the mobile middleware controls the sensors so that only sensor data required to determine whether the CMQ is satisfied needs to be transmitted so as to reduce energy consumption during the performance of the monitoring. Therefore, the mobile middleware can perform energy-efficient context monitoring, required by the context-aware application programs.

Claims

1. Mobile middleware, comprising:

a Context Monitoring Query (CMQ) processor for storing requested CMQS, receiving sensor data from sensors, monitoring whether the stored CMQs are satisfied, and transmitting an event according to results of the monitoring; and

a Reduced Source Cover (RSC) manager for controlling activation of the sensors so that, of the received sensor data, only data about context elements belonging to a minimum context element set (RSC) required to determine whether the CMQs are satisfied is generated.

2. The mobile middleware according to claim 1, wherein the mobile middleware is used in a Personal Area Network (PAN) environment.

3. The mobile middleware according to claim 1, wherein each of the CMQs comprises:

a NOTIFY clause for specifying Identifications (IDs) of context-aware application programs that requested respective CMQs;

a CONDITION clause for specifying at least one condition, including any one of the context elements, an operator, and a condition value, in a conjunctive normal form; and

a DURATION clause for specifying a time for which the monitoring is maintained.

4. The mobile middleware according to claim 1, wherein the CMQ processor comprises:

a CMQ table for storing query IDs, which are required to identify the CMQs, query results, which indicate results of the CMQs, and query elements, which indicate conditions included in the CMQs; and

a CMQ index for storing IDs of the context elements and current values of the context elements.

5. The mobile middleware according to claim 4, wherein each of the query elements comprises IDs of respective context elements, interval conditions, indicating ranges required by the context elements, and element results, indicating whether respective context elements satisfy the interval conditions.

6. The mobile middleware according to claim 4, wherein the CMQ index comprises:

an RS list including Region Segment (RS) nodes, generated by dividing possible values of the context elements, into region segments according to the ranges required by the CMQs; and

a source table having IDs of respective context elements, and pointers for pointing at RS nodes, including current values of the context elements.

7. The mobile middleware according to claim 1, wherein the RSC manager comprises:

an RSC calculator for calculating the RSC required to determine whether the CMQs are satisfied with reference to the results of the monitoring; and

a sensor controller for stopping sensing and data transmission performed by sensors, which provide data about context elements that do not belong to the RSC, or for reducing a data transfer rate of the sensors.

8. The mobile middleware according to claim 7, wherein the RSC calculator obtains a ‘

true’

context element set, which is a set of all ‘

true’

context elements, included in CMQs having results of ‘

true’

, among the CMQs, obtains a ‘

false’

context element set, which is a set of all ‘

false’

context elements, included in CMQs having results of ‘

false’

, among the CMQs, obtains a minimum ‘

false’

context element set, for which each CMQ having a result of ‘

false’

includes one or more ‘

false’

context elements and in which a number of ‘

false context elements’

is a minimum, among subsets of the ‘

false’

context element set, obtains a union of the ‘

true’

context element set and the minimum ‘

false’

context element set, and calculates the RSC without considering a first context element, when any one of CMQs, results of which become ‘

false’

due to the first context element included in the minimum ‘

false’

context element set in the union of the sets, can be determined to be ‘

false’

due to a second context element included in the ‘

true’

context element set.

9. The mobile middleware according to claim 8, wherein the minimum ‘

false’

context element set is an approximate minimum ‘

false’

context element set obtained using a greedy heuristic method.

10. The mobile middleware according to claim 1, further comprising a data processor for receiving the sensor data from the sensors and transmitting the sensor data to the CMQ processor.

11. The mobile middleware according to claim 10, wherein the data processor comprises:

a data collector for receiving the sensor data from the sensors and outputting the sensor data; and

a feature generator for receiving the sensor data from the data collector, extracting feature values from the sensor data, and outputting the feature values.

12. The mobile middleware according to claim 11, wherein the RSC manager comprises:

an RSC calculator for calculating the RSC, required to determine whether the CMQs are satisfied, with reference to the results of the monitoring;

a sensor controller for stopping sensing and data transmission performed by sensors, which provide data about context elements that do not belong to the RSC, or for reducing a data transfer rate of the sensors; and

a feature controller for controlling the feature generator so that a procedure for calculating feature values corresponding to context elements that do not belong to the RSC is obviated, thus reducing energy consumption caused by the procedure for calculating the feature values.

13. The mobile middleware according to claim 1, further comprising a context broker for converting the requested CMQs into system-level CMQs and outputting the system-level CMQs to the CMQ processor.

14. A context monitoring method, comprising:

registering a requested Context Monitoring Query (CMQ);

receiving sensor data from sensors and monitoring whether the registered CMQ is satisfied;

controlling activation of the sensors so that, of the received data, data about context elements belonging to a Reduced Source Cover (RSC) required to determine whether the CMQ is satisfied, is generated; and

providing an event according to the results of the monitoring.

15. The context monitoring method according to claim 14, wherein the context monitoring method is used in a PAN environment.

16. The context monitoring method according to claim 14, wherein the registering the CMQ comprises:

converting the requested CMQ into a system-level CMQ; and

storing the system-level CMQ.

17. The context monitoring method according to claim 14, wherein the controlling the activation of the sensors comprises:

calculating the RSC, required to determine whether the registered CMQ is satisfied, with reference to the results of the monitoring; and

stopping sensing and data transmission performed by sensors, which provide data about context elements that do not belong to the RSC.

18. The context monitoring method according to claim 14, wherein:

the monitoring whether the registered CMQ is satisfied is performed to receive the sensor data and feature value, extracted from the sensor data, and to thus monitor whether the registered CMQ is satisfied; and

the controlling the activation of the sensors is performed to control activation of the sensors and generation of the feature values so that, of the received sensor data and the received feature values, data about only context elements belonging to the RSC required to determine whether the CMQ is satisfied, is generated.

19. A context-aware service system, comprising:

at least one context-aware application program for requesting a Context Monitoring Query (CMQ) and receiving an event when the CMQ is satisfied;

at least one sensor for sensing user context information and generating sensor data; and

mobile middleware for receiving a request for the CMQ from the context-aware application program, registering the CMQ, receiving the sensor data from the sensor, monitoring whether the CMQ is satisfied, providing an event according to results of the monitoring, and controlling the sensor to reduce energy consumption caused by performance of the monitoring.

20. A context-aware service provision method, comprising:

at least one context-aware application program requesting a Context Monitoring Query (CMQ);

registering the requested CMQ;

receiving sensor data from at least one sensor;

monitoring whether the registered CMQ is satisfied using the sensor data received from the sensor;

calculating a Reduced Source Cover (RSC), required to determine whether the registered CMQ is satisfied during performance of the monitoring;

controlling the sensor according to results of calculation;

providing an event to the context-aware application program according to results of the monitoring; and

deleting the registered CMQ when a duration of the registered CMQ has elapsed.