Methods for Coalition Formation in Adaptation-Based Social Networks Levi Barton, Vicki H. Allan Utah State University

Overview Optimal Coalitions Dynamic Environment Agent Organized Network Agent Types Results Conclusions Questions

Optimal Coalition Formation Requires Complete Information Substantial Computation Time May Not Be Feasible

Dynamic Environment Incomplete Information –Limited Sensor Capabilities –Damaged Sensors –Communication Failures

Dynamic Environment Agents –Limited View of Environment –Discovery of Environment Tasks –Periodic Creation –Decreasing Value –Time Sensitive

Agent Organized Network Agents in Charge –Choose Neighbors –Choose Tasks

Agent Organized Network Network Arcs –Physical Distance –Limited Communication –Trust –Potential Team Members

Agent Organized Network Initial Network Arcs –Random Agent Locations –Distance Between Agents d –Arcs Added When d < 100

Agent Organized Network Tasks –Require Specific Skills –Specified by Array skillCount[1,…,skillMax]

Agent Organized Network Agents Paired to Tasks in Teams –Agent Team Connected in Network –Teams Formed Using Set of Friends of a Friend (FOAF) –FOAF Agent Set of Preferred Neighbors

Agent Organized Network Agent Skills –One Skill Per Agent Neighborhood Skills –Skills Possessed by Neighbors and Neighbor’s Neighbors (FOAF)

Agent Organized Network Agent Flow of Control

Rewiring Strategies Performance –Rewire Based on Performance Estimate Structural –Rewire Based on Network Structure Diversity –Rewire Based on Skill Diversity

Task Selection Basic –Select First Available Task Strategic –Select Best Available Task (If Ratio of Skills Needed in Task and Skills Available in Neighborhood is > 0.34)

Task Patience Patient –Remain Committed To Task Until Task Either Succeeds or Fails Impatient –Abandon Task if Number of Uncommitted Agents in Neighborhood is < Number of Skills Unfilled in Task

Agent Types

Four Categories –Basic Task Selection and Task Patience –Basic Task Selection and Task Impatience –Strategic Task Selection and Task Patience –Strategic Task Selection and Task Impatience

No Adaptation Basic + Patient Strategic + Patient Basic + Impatient Strategic + Impatient

No Adaptation

Performance Agents

Structural Agents

Maximum Committed Four Time Steps

Maximum Committed Ten Time Steps

Two Tasks Per Time Step

Four Tasks Per Time Step

Degree Limit of Five

Degree Limit of Ten

Degree Limit of Twenty

Average Density Degree Limit of Five

Average Density Degree Limit of Ten

Average Density Degree Limit of Twenty

Conclusions Best Agent Type –StructuralStratImpatient Agent Impatience Under High Task Load Strategic Under High Task Load Degree Limit Feasible

Questions?