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

Environment”

Smirnova Vira

”Cheese Factory”/ 19.12.2002

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

Multi-agent systems are collections of several computational entities,

called agents, interacting with one another

MAS can be characterized as:1. each agent has incomplete information or capabilities for

solving the problem and, thus, has a limited viewpoint,2. there is no global control in the system,3. location of data is decentralized and

4. computation is asynchronous.

AOIE and PAGE paradigms

A – Agent

O – Organization

I – Interaction

E – Environment

P- Percepts

A – Actions

G- Goals

E - Environment

Distributed Sensor Networks General DSN (architecture)

DSN

example of one cluster

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

MADSN

DSN

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

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

Peer-to-Peer

By realizing DDF I have used some of ideas from P2P systems.

P2P – collection of distributed resources connected by a network.

P2PDSNThe 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

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

Interactions between agents

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

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

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

Comparison between DSN, MADSN and P2PDSN models

 

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

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

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.

Further workUnanswered 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.