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“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.