Methods for Coalition Formation in AdaptationBased Social Networks

1
Methods for Coalition Formation in
Adaptation-Based Social Networks

• Levi Barton, Vicki H. Allan
• Utah State University

2
Overview

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

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Optimal Coalition Formation

• Requires Complete Information
• Substantial Computation Time
• May Not Be Feasible

4
Dynamic Environment

• Incomplete Information
• Limited Sensor Capabilities
• Damaged Sensors
• Communication Failures

5
Dynamic Environment

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

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Agent Organized Network

• Agents in Charge
• Choose Neighbors
• Choose Tasks

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Agent Organized Network

• Network Arcs
• Physical Distance
• Limited Communication
• Trust
• Potential Team Members

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Agent Organized Network

• Initial Network Arcs
• Random Agent Locations
• Distance Between Agents d
• Arcs Added When d lt 100

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Agent Organized Network

• Tasks
• Require Specific Skills
• Specified by Array skillCount1,,skillMax

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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

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Agent Organized Network

• Agent Skills
• One Skill Per Agent
• Neighborhood Skills
• Skills Possessed by Neighbors and Neighbors
  Neighbors (FOAF)

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Agent Organized Network

• Agent Flow of Control

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Rewiring Strategies

• Performance
• Rewire Based on Performance Estimate
• Structural
• Rewire Based on Network Structure
• Diversity
• Rewire Based on Skill Diversity

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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 gt 0.34)

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Task Patience

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

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Agent Types
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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

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No Adaptation
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No Adaptation
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Performance Agents
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Structural Agents
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Maximum Committed Four Time Steps
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Maximum Committed Ten Time Steps
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Two Tasks Per Time Step
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Four Tasks Per Time Step
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Degree Limit of Five
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Degree Limit of Ten
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Degree Limit of Twenty
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Average Density Degree Limit of Five
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Average Density Degree Limit of Ten
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Average Density Degree Limit of Twenty
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Conclusions

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

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Questions?