“Multi-Agent Systems for Distributed Data Fusion in Peer-to-Peer Environment”

1. “Multi-Agent Systems for Distributed Data Fusion in Peer-to-Peer Environment” Smirnova Vira ”Cheese Factory”/ 19.12.2002

2. Main goals • To design a new model for fault-tolerant and high availability of Distributed Sensor Networks and data fusion • To modify existing data fusion process into a new one by combining multi-agent systems with P2P environment • To consider the behaviour of the system in common failure conditions • To compare complex distributed systems such as DSN, MADSN and P2PDSN

3. Multi-agent systems • are collections of several computational entities, called agents, interacting with one another MAS can be characterized as: • each agent has incomplete information or capabilities for solving the problem and, thus, has a limited viewpoint, • there is no global control in the system, • location of data is decentralized and • computation is asynchronous.

4. AOIE and PAGE paradigms P- Percepts A – Actions G- Goals E - Environment A – Agent O – Organization I – Interaction E – Environment

5. Distributed Sensor Networks • General DSN (architecture) example of one cluster

6. MADSN – Mobile Agent based Distributed Sensor Network • is an extension of DSN that is based on applying mobile agent technologies The difference between them is that MADSN is an improved DSN architecture that uses mobile agents

7. Data Fusion I • Centralized DF is characterized by a hierarchy of nodes, in which all information is passed up the hierarchy to a centralized fusion node • disadvantages: • low availability of the fused picture at the lower level nodes • a single point of failure in the system • limits the ability of the individual participants to operate independently • can require significant communications bandwidth

8. Data Fusion II • Decentralized DF – is charecterised by system that consists of a network of sensors nodes each with its own processing facility. • advantages: • higher availability of the fused picture at the lower level nodes • no single point of failure in the system • no global knowledge of sensor network topology (just knowledge about neighbors) • bandwidth requirements are less then CDF

9. Peer-to-Peer By realizing DDF I have used some of ideas from P2P systems. P2P – collection of distributed resources connected by a network.

10. P2PDSN The whole model consists of several major functional modules: • collecting of measurements from sensors, • analyzing of collected data, • representation of data to user and • controlling and monitoring the current state of Distributed Sensor Network

11. Agents and their Organization in the System • “1” – (CA – SA) Control messages • “2” – (SA – CA) Sensors’ measurements • “3” – (CA – AA) Push measurement data • “4” – (AA – CA) Push analyzed data • “5” – (VA – CA) Request for getting analyzed data, Request for commands • “6” – (CA – VA) Analyzed data • “7” – (user – VA) User’s requests and commands • “8” – (VA – user) Representation of analyzed data

12. Interactions between agents the idea of interaction is not only transfering bits through channel, it means to reach the high-level interoperability via communication!

13. States of P2PDSN Each of the presented agents has their own tasks, responsibilities and goals which depends ot their state A state of agent is controlled by the arrival and content of the message Example of state diagram

14. Deficiencies in System States There are four main categories that were not taken into account in the design and require further research: • 1.      Tampering of agents, • 2.      Tampering of messages, • 3.      Unreliability of the network and • 4.      The implementation of the system

15. Metrics DSN MADSN P2PDSN Network topology Hierarchic star Hierarchic ring Mesh Transferred entities Data Computation Data Bandwidth consumption High Low Medium Scalability No Yes Yes Extensibility Low Medium High Load balancing No No Yes Information repository Hierarchic Hierarchic Distributed Search efficiency High High Low Fault-tolerance Low Medium High Information coherence Low Medium High Comparison between DSN, MADSN and P2PDSN models

16. Conclusion • was developed a model that allows disparate systems to interact automatically with one another in order to optimize data fusion and data management processes • was described in the thesis multi-agent system suits well for realizing P2PDSN system because of the desired characteristics it possesses which allow agents to represent a peers due to their autonomous and social nature

17. Conclusion (2) From an engineering point of view the system is: • fault-tolerant because there is no a single point of failure, • high-available, because there are several copies of the same data but in different locations, • extensible because new peers (agents) can be added dynamically and • flexible according to previous benefits.

18. Further work Unanswered questions are: • the security, • loosing of messages, • loops, • denial of services and technical possibilities of devices that can be used in the system. Also the system has to be implemented for more detail testing and verifying that all the components work together.

19. Thank you for your attention!!!