On Accessing GSM-enabled Mobile Sensors

1. On Accessing GSM-enabled Mobile Sensors Zissis K. Plitsis, Ioannis Fudos, Evaggelia Pitoura and Apostolos Zarras University of Ioannina, Greece The Distributed Management of Data Laboratory ISSNIP 2005

2. Outline • Motivation and Approach • Technology and Services • System Architecture • Use Case: Integrating a Mobile Camera • Performance Evaluation • Conclusions On Accesing GSM-enabled Mobile Sensors

3. Motivation Accessing various kinds of GSM-enabled Mobile Sensors • Delivering image, temperature, seismic activity, measurements and other textual or not information • Controlled by SMS messages and delivering information by SMS/MMS On Accesing GSM-enabled Mobile Sensors

4. Motivation Our goal is to automate the process of incorporating these mobile sensors, in an ubiquitous and heterogeneous computing environment On Accesing GSM-enabled Mobile Sensors

5. Approach Introduction of: • A middleware framework that enables uniform WEB-based access to mobile sensors • Mobile Sensor Control Description (MSCD), describing sensor behavior and functionality On Accesing GSM-enabled Mobile Sensors

6. Approach • Produce HTML-based and WAP-based interfaces • Instantiate a sensor-customized proxy server, serving client requests for sensor information On Accesing GSM-enabled Mobile Sensors

7. Technology and Services S.M.S.: Short Message Service or Short Message Sending • Widely supported in mobile phones in most countries • Communication between mobile phones with short textual messages in an asynchronous way, as e-mails for mobile phones • Binding together the pertinent telephony and computing protocols with SMS comes “naturally”, as SMS can be used to form protocols • Relatively inexpensive On Accesing GSM-enabled Mobile Sensors

8. Technology and Services Except from HTTP, compatibility with WAP is provided by our system WAP (Wireless Application Protocol) allows low-end devices with limited CPU power, memory and storage to access the wireless WEB • Uses WML for publishing pages, containing cards for browsing in small screens with limited capabilities On Accesing GSM-enabled Mobile Sensors

9. Our Goal The proposed middleware framework is reflective as it self-customizes its interfaces with respect to behavioral constraints of the particular mobile sensor Our goal is: Web-based access transparency over mobile sensors On Accesing GSM-enabled Mobile Sensors

10. System Architecture Our framework consists of: A mobile sensor customizer,server proxies and WEB page proxies … On Accesing GSM-enabled Mobile Sensors

11. Architecture On Accesing GSM-enabled Mobile Sensors

12. Architecture Mobile Server Customizer and MSCD On Accesing GSM-enabled Mobile Sensors

13. Mobile Sensor Customizer and MSCD • Unifying the communication between clients and mobile sensors by providing the WEB-based interfaces • Using as input an MSCD, acquire the SMS control sequence that perform the operations on the mobile sensor • The MSCD of a mobile sensor, provided by means of an XML file, consists of the following elements: • Initialization information • Query delivery information • An XML scheme describes the structure of MSCD files On Accesing GSM-enabled Mobile Sensors

14. Example of a Mobile Sensor Control Description file for a mobile sensor providing images and temperature via SMS or MMS; the GSM Camera is the use case that will present later on.

15. An example of the initialization information in the MSCD file.

16. Examples of the delivery information in the MSCD file.

17. Architecture Server Proxy and WEB page Proxy On Accesing GSM-enabled Mobile Sensors

18. Application server: Server Proxy and WEB Page Proxy • Proxy Server • Collects requests for information issued by clients and translates them into sequences of sensors-specific SMS messages • Receives the specified information and makes it available in client-compatible formats • WEB Page Proxy • Builds a WEB page that contains the results obtained by the sensor, when this is requested The Proxy Server uses polling while waiting the page creation with the results and informs the client for the progress and the completion, in the case of HTTP, with a popup window. On Accesing GSM-enabled Mobile Sensors

19. Use Case: Integrating a Mobile Camera Mobile Camera: Nokia Observation Camera; a stand-alone remote GSM-GPRS device with imaging hardware, motion detector, thermometer and microphone, ready to operate where there is GSM coverage On Accesing GSM-enabled Mobile Sensors

20. Integrating a Mobile Camera (2/4) The MSCD specification for the camera, shown in the example previously, is used for: • Customization of the proxy server and WEB page proxy • Creating the corresponding HTML and WAP based interfaces On Accesing GSM-enabled Mobile Sensors

21. Integrating a Mobile Camera (3/4) • The HTML interface consists of a form, by witch the client determines the context and the delivery information • Image and temperature may will be delivered in a result web page • Similarly the requested information may will be delivered as an MMS or SMS message On Accesing GSM-enabled Mobile Sensors

22. HTML Form for Selection

23. An instance of the interaction protocol

24. Result Page

25. Integrating a Mobile Camera (4/4) • The HTTP and WAP based interfaces: • http://sensor-proxy.cs.uoi.gr/index_ds.htm • wap://sensor-proxy.cs.uoi.gr/index_ds.wml Please, feel free to try them later! On Accesing GSM-enabled Mobile Sensors

26. Performance Evaluation Performance Evaluation to measure: The overhead introduced by our middleware framework in the case of accessing the GSM Camera. On Accesing GSM-enabled Mobile Sensors

27. Performance Evaluation (2/6) Query experiments performed: • Request image and temperature, through HTML-based interface • with image resolution default, high and compact • delivering on a WEB page • Request temperature only, through HTML-based interface • delivering to a mobile phone with an SMS message • The above experiments submitted through the WAP-based interface On Accesing GSM-enabled Mobile Sensors

28. Performance Evaluation (3/6) Measurements: • preparation time required by the server for sending the SMS messages to the mobile camera, in fact : the middleware framework overhead • overall response time, from the submission until the reception of results On Accesing GSM-enabled Mobile Sensors

29. Performance Evaluation (4/6) The Response time of the middleware was divided into three parts: • the preparation time required by the server • the processing time for the camera for sending the SMS/MMS messages with information, and • the time for message unpacking and processing at the WEB page proxy On Accesing GSM-enabled Mobile Sensors

30. Performance Evaluation fig.1

31. Performance Evaluation (5/6) • Important overhead of preparation at the proxy server, based on the server capabilities and the number of requests • This overhead is close to double in the case of many SMS control messages, when e.g. the resolution mode should change to high or compact and as expected: • High resolution mode results in larger image files and more time for unpacking the MMS messages that contains them On Accesing GSM-enabled Mobile Sensors

32. Performance Evaluation fig.2

33. Performance Evaluation (6/6) The overhead introduced by our middleware framework: • Almost doubles the time required by the system to deliver the results • Currently we work on reducing the overhead by optimizing the implementation and the capabilities of our prototype On Accesing GSM-enabled Mobile Sensors

34. Conclusions “WEB-based access transparency over different types of mobile sensors” can be achieved by: • XML-based control descriptions that specify the proprietary SMS/MMS-based communication protocols assumed by the sensors, leading to automated customization • WEB-based interfaces (HTML and WAP), based in the MCSD of the sensors On Accesing GSM-enabled Mobile Sensors

35. Conclusions An instance of the proposed middleware framework was implemented and evaluated for a GSM-enabled camera • A MSCD file was used for this camera and the functionality that it provide • That file specified the servers, the user interfaces that should be used and provide some protocols of requesting information On Accesing GSM-enabled Mobile Sensors

36. On Accessing GSM-enabled Mobile Sensors Thank you University of Ioannina, Greece The Distributed Management of Data Laboratory ISSNIP 2005

37. On Accessing GSM-enabled Mobile Sensors Questions… Feel free to try the following HTTP and WAP based interfaces: • http://sensor-proxy.cs.uoi.gr/index_ds.htm • wap://sensor-proxy.cs.uoi.gr/index_ds.wml On Accesing GSM-enabled Mobile Sensors