1. Semantic Web Based Architecture for Managing Hardware Heterogeneity in Wireless Sensor Network Authors: Sinisa Nikolić, MSc Valentin Penca, MSc Milan Segedinac, MSc Prof. Zora Konjović, PhD UNIVERSITY OF NOVI SAD FACULTY OF TEHNICAL SCIENCES SERBIA

2. Outline Introduction Existing solutions GLOSENT architecture Case study Conclusion 2of 20

3. Introduction WSN – a lot of sensor nodes(SN) SN – small size, low cost, battery- powered, processing, sensing, wireless communication WSN is not an isolated entity SWSN (System of WSNs) – user applications interact with heterogeneous WSNs 3of 20

4. Introduction (2) Heterogeneity of WSN appears both in hardware and software Ontology based-model for solving hardware heterogeneity in SWSN Specific middleware that provides communication based on exchange of ontologies 4of 20

5. Existing solutions Specific based and generic (middleware) based Key aspects TinyDB WSN is a distributed database, SQL like query, TinyOS Squawk Virtual machine (VM) based, specific application programming language, VM for a set of hardware platforms Impala Event-based programing model, mobile code is written from predefined set of instruction Mires Event-based, message oriented communication, publish/subscribe paradigm, Consumer (Appliaction)/ Producer(SN), TinyOS Table 1 – Existing middlewares 5of 20

6. Existing solutions SOA Multi layer architecture of WSN, services for gathering data, xml description of hardware OX-Framework – using OGC standards (describe types and usage of WSN entities), without sematic description and technologies 6of 20

7. Existing solutions Semantic Raw sensor data to reconstruct the context of event, hieratical organization semantic information and semantic services Ontologies for providing adaptive WSN Contextual ontologies to provide more flexible information processing 7of 20

8. GLOSENT Architecture GLObal SENsor neTwork deals with hardware heterogeneity using semantic technologies 8of 20

9. GLOSENT Architecture Figure 1 – The GLOSENT architecture 9of 20

10. Application segment Consist of Application proxy and Subapplications Subapplication – user application that uses appropriate communication methods and data formats Application proxy – bridge between sub placation and other parts of system Figure 2 – Application segment 10of 20

11. WSN segment Role of this segment is in gathering information and data representation from the sensor node network WSN modeled with metadata that describe: structure, method of use and control and data formats SN is a generalized notion related to any WSN device (base stations, rich uncles, routers, etc.) Uniform WSN representation relaying on ontology Figure 3 – WSN segment 11of 20

12. Middleware segment Mediates in the communication of WSN segment and application segment in a SWSN Middleware is not physical part of system, it is consisted from data (ontologies) of all mentioned proxies 12of 20

13. System Image Solving hardware heterogeneity in WSN consists of metadata models describing different WSN hardware platforms, metadata values describing particular devices and their relations, and sensor data (raw and/or aggregated sensor readings) current state of all WSN, represented with ontologies 13of 20

14. System Image Figure 4 – WSN ontology 14of 20

15. Implements the data persistency Stores the System image data and the information about Subapplications Central storage Figure 5 – Central storage 15of 20

16. Model of the WSN hardware platform SunSPOT SunSPOT is a WSN sensor node developed by Sun Microsystems. The device was developed based on IEEE 802.15.4 standard. SunSPOT can be used to measure light, temperature and acceleration, but its functionality can be extended with additional sensors Case study: Modeling SN in GLOSENT 16of 20

17. Some basic functionalities of SunSPOT device Extensible classification Classification of SunSPOT hardware components Figure 6 – Classification of components 17of 20

18. Cental storage based on SunSPOT contains the metadata that describe specific properties of SN general properties of each hardware platform Table 1 – TypeSN Table 2 – TypeSNProperties 18

19. Conclusion We have proposed an ontologically-based approach for modeling SWSNs The topology of the WSN is represented by high- level ontology, while the semantics of WSN is represented by appropriate classifications The GLOSENT architecture successfully solves the problem of WSN hardware heterogeneity 19of 20

20. Future work Dealing with other aspects of heterogeneity Using ontologies for representing Service Comand pattern based on ontologies Context-sensitive ontologies 20of 20

21. Thank you for attention! Questions?