Small Boat Attack in Malacca Straits
Small Boat Attack in Malacca StraitsChiam, Tou Wei (David)Lee, Kah HockNov 3, 2011
OA4202 Project Presentation
Background
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Threat of Small BoatsUSS ColeSea Tigers (LTTE)Gibraltar Plot
Why ?Fast and ManeuverableNarrow Sea StraitsHeavy Shipping TrafficSovereign Islands and CoastsSmall Boat Threat1. 2002, Aden, Yemen, Problem for the Small Boat
3What is the best Starting Location & Minimum Risk Path to attack a Naval Warship along Malacca Straits ?
Naval WarshipTerrorist Small BoatMalacca StraitsAssumptions
4Warship is moving at constant speed, along a pre-determined route independent of small boat.
Small Boat Threat is aware of Warship locations at each point along its route.
Movement and Distances are based on the Manhattan convention.
As our project is unclassified, Data is generic and not based on actual operational systems.
Channel of Interest : Width 45 nm, Length 50 nmGridded Map :Abstraction to Network Model
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= 5 nm x 5 nm Malacca Straits9 Squares10 Squares
Network Representation
6Nodes Position of Ships on Grid per time stepEdges Movement of Small Boat to next time step
Time Step: 15 mins (5nm @ cruise speed of 20 kts)t minst + 15 minst + 30 mins
Small Boat Movement Edges
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1. Stationary or Loiter2. Slow (20kts)3. Fast (40 kts)Based on Speed :
Based on Environment :No Entry to Land Nodes
2. Slow Speed upon entry, exit and within Shipping Lane
Edge Costs
Edge Cost = Reliability (0 to 1) = 1 - Risk (0 to 1)Risk Components: 1. Exposure Risk Environmental Cover 2. Proximity Risk Distance to Warship 3. LOS Risk Line-of-Sight with Warship8Total Edge Risk = [(We * Exposure Risk) + (Wp * Proximity Risk)] * LOS Risk
We,Wp : Normalised weights for multi-objective risk assessment (currently set to be equal, 0.5)Risk Assignment
Exposure Risk
Proximity Risk
Within LOS Risk Factor = 0.8
In Shipping LaneNear Coast (< 10nm)Risk LevelYesYes0.1YesNo0.2NoYes0.4NoNo0.8Distance from WarshipRisk Level< 10 nm0.910 to < 15 nm0.5>= 15 nm09Minimum Risk to Shortest Path LP
10Attacks on the Network
11Surveillance Points on Grid - Coastal Radars, Cameras - Escorts - Patrol Aircraft
Surveillance Effects - Edge Level: Reduces Reliability of a single edge - Node Level: Reduces Reliability of all incoming edges
Surveillance EffectAdditional Edge CostBlocking(# time steps) x max(edge cost)Degradation0.5 Maximize Attack Effects
12Max-Min conversion for GAMS
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ABCDResults: Fixed Start Locations
14CAStart LocationProbability to reach HVUSteps to ReachA0.2354B0.1084C0.0447D0.02011BDResults: Any Start Location
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Takes most Direct Route to Warship as she comesShipping LanesExploits Shipping Lanes and Coast for coverMinimal Risk Path starts near to WarshipB Small Boat Path Warship Path Coastal Land SeawaterSurveillance Effects on Path
16Edge BlockingNode BlockingB Small BoatW Warship Path Incoming Edge Blocked Destination Node Blocked
Node Blocking Trends
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SP=0SP=1SP=2SP=3
SP=4SP=5SP=6SP=7SP = # Surveillance PointsNode Degradation Trends
18SP=0SP=1SP=2SP=3SP=4SP=13SP=14SP=15SP = # Surveillance Points
Operator Resilience Curves
193: All nearby paths with Shipping Lanes and Coast Cover are blocked
SP=2SP=35-7: Minimal Changes in Path Direction 8-11: Projected to Completely Block at 11.Operator Resilience Curves
203: All nearby paths with Shipping Lanes and Coast Cover are blocked5-7: Minimal Changes in Path Direction 8-11: Projected to Completely Block at 11.
SP=5SP=6SP=7Operator Resilience Curves
213: All nearby paths with Shipping Lanes and Coast Cover are blocked5-7: Minimal Changes in Path Direction 8-11: Projected to Completely Block at 11.
SP=7Operator Resilience Curves
223: Path crosses a SP14: All possible degradation Nodes covered in Direct Path to WarshipSP=2SP=3
SP=0
Operator Resilience Curves
233: Path crosses a SP14: All possible degradation Nodes covered in Direct Path to WarshipSP=14SP=15
SP=0
Mixture of Surveillance Assets
24Consider 2 types of assets:Small AreaInfluences arcs connecting nearest neighborPenalty 50%Large AreaInfluences arcs connecting up to 2 nodes awayLess effective than short range (Penalty 20%)
Mixture of Surveillance Assets
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From 3 assets onwards, Small Area asset has more impact
9Mixture of Surveillance Assets
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Large Area asset complements limitation of Small Area asset
Mixture of Surveillance Assets
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If we had more time
28Potential EnhancementsInterdiction represented by path in time (Persistence)Mixture of Area and Directional influence assetsCosts of assets, subject to budgetConcurrent attempt by more than 1 boat
29
~ Questions ~
Computational Complexity
30# Nodes : - Length (10) x Width (9) x Time Steps (13) = 1170 - With Start, End Nodes & Inaccessible Land Nodes = 847
# Edges : - Moves per node = Stationary(1) + Slow(4) + Fast (8) = 13 - # Nodes x Moves per node = 10895 - With Start, End Nodes and Prohibited Moves = 5698
General LP : O(big x small2) = O(n x m2) MIP :O(# branch iterations x (n x m2))