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

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~ 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))