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North Slope Decision Support System: Ice Road Planning Algorithms 3 rd Stakeholder Workshop April 27-28, 2011

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Ice Road Routing: A Complex Problem Often multiple exploration sites Sometimes multiple possible starting points Avoidance of undesirable/difficult features Water availability Regulatory issues Path re-use in future seasons Multiple objectives Cost Time Risk/Reliability

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Ant Colony Systems Based on natural behavior of ants in route finding between nest and food Pheromones! Algorithm Development

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Ant Colony Systems Based on natural behavior of ants in route finding between nest and food Pheromones! Algorithm Development

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Ant Colony Systems Based on natural behavior of ants in route finding between nest and food Pheromones! Algorithm Development

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Ant Colony Systems Based on natural behavior of ants in route finding between nest and food Pheromones! Algorithm Development

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Issues to Solve Ants get lost in complex and open topologies Most traditional ACS applications are single objective Our real-world ants have to build their own roads and need water

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Graph Pruning Keep ants from getting lost by reducing topology to non-redundant paths

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Graph Pruning Keep ants from getting lost by reducing topology to non-redundant paths

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Traditional ACS includes link choice heurisitics Exploration versus Exploitation Probabilistic Choice weighted by pheromones and a priori suitability scores Multi-Objective Path-Finding Pher 1 Suit 1 Pher 2 Suit 2 Pher 3 Suit 3

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Multi-objective ACS includes multiple suitability scores, preference functions, and non- dominated sorting to find pareto-fronts Multi-Objective Path-Finding Pher 1 SuitA 1 SuitB 1 SuitC 1 Pher 2 SuitA 2 SuitB 2 SuitC 2 Pher 3 SuitA 3 SuitB 3 SuitC 3 Obj A Obj B

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22 11 33 As the ants move along the path, they search for the nearest available permitted lake to withdraw water from. Water Accounting 4

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On large open grids, sometimes the paths will have unnecessary bends or curves. Path Straightening

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The ants can determine the best starting point given a stretch of road. Multiple Start Points

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Steiner Problem Minimum Spanning Tree Multiple End Points Waypoint

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Steiner Problem Minimum Spanning Tree Multiple End Points

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When there are more than 3 endpoints then pheromone sharing is used. Multiple End Points

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START END RouteTravel Time (hrs) Construction Cost ($) New Permits Needed Orange0.251,400,0002 Green0.41,000,0001 Blue0.451,200,0000

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The resolution of the roads are limited by the 100m x 100m DEM data used. Water accounting for road construction is dependent upon available lake data. Some data may not be available. Limitations

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Demonstration

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1. Review Permitting Matrix 2. Lets sketch out planning process and identify tasks that NSDSS can help improve How does NSDSS fit into the planning process?

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Permitting Matrix

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Planning Process