MarkSAT

1
MarkSAT

• W. E. Walsh and M. P. Wellman

2
Objectives

• Offer a decentralized computation model
• Study the computational properties of
  decentralized systems
• Study how to use market model to solve SAT
  problems

3
Supply Chain Formation

• A Task dependency network
• A directed, acyclic graph (V, E)
• V G?A
• G goods, A agents
• A C???S
• C consumers, ? producers, S suppliers
• E edges
• lta, ggt agent a can provide a unit of good g
• ltg, agt agent a requires a unit of good g

4
Supply Chain Formation 3SAT

• 3SAT can be transformed into supply chain
  formation problem
• Supply chain formation problem is NP-Complete

5
Implementation of Decentralization

• An agent knows only the information of the goods
  in which it is interested
• An agent tries to maximize its surplus based on a
  price system
• Protocol in price system auction (price quotes
  and bidding)
• Global view
• Local interaction
• Local price information
• Local decision making

6
Features

• Distributed
• More distributed than Yokoos approaches
• Inefficient
• Much slower than GSAT
• Two much communication

7
Reference

• W. E. Walsh and M. P. Wellman, MarketSAT An
  Extremely Decentralized (but Really Slow)
  Algorithm for Propositional Satisfiability, in
  Proceedings of 17th National Conference on
  Artificial Intelligence, 2000