Group Transit Scheme Optimization

As one of the counter-piracy measures, the Group Transit Scheme was established in 2010 for vessel transiting the Gulf of Aden by Maritime Security Center -- Horn of Africa. The current group transit schedules divide transiting vessels into 5 groups of varying speeds uniformly spaced between 10 and 18 knots. Our motivation is -– based on the distribution of actual speeds of vessels transiting the Gulf -– to optimize the static group transit schedule and eventually provide a dynamic grouping scheme which takes into account not only the speed of transiting vessels however also their time of arrival.

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Current Group Transit Scheme

Gulf of Aden Group Transits are designed to group ships into different speed groups in order to exploit additional protection and assurance of traveling in a group. Each transit follows a recommended navigation track (NAV-TRACK) through the International recommended transit corridor (IRTC) at a published speed that avoids highest-risk piracy areas and time intervals and allows maximum effectiveness of supporting military assets if needed. There is one transit per day for each speed group -- see the Table below.

Speed Entry point A - time Entry point B - time
10 kts 04:00 GMT+3 18:00 GMT+3
12 kts 08:30 GMT+3 00:01 GMT+3
14 kts 11:30 GMT+3 04:00 GMT+3
16 kts 14:00 GMT+3 08:30 GMT+3
18 kts 16:00 GMT+3 10:00 GMT+3

The times for different speed groups to enter the IRTC are calculated so that the groups pass through the area of statistically greatest risk, between 47E and 49E, at night and they ensure that all ships, regardless of speed, are together at first light. This allows the military forces in the area to best position their assets in the area so as to protect ships against piracy and to provide assistance in case of attack.

 Group Transit Scheme Visualization

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Optimal Group Transit Schedules

The distribution of speeds of the transiting merchant vessels is expressed by a histogram with bins of a fixed width (can be set e.g. to 0.1, 0.5 or 1). The optimization problem can be formulated as a partitioning the bins with different vessel count into N groups to minimize the average delay of vessels when transiting the gulf.

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Dynamic Grouping

Dynamic transit grouping takes the optimization a step further by forming the groups dynamically based on the type and constraints of incoming vessels, rather then using a fixed schedule. In dynamic grouping, all transiting vessel register to a centralized authority, which dynamically assigns incoming vessels to groups with the most similar speed and smallest distance. Before entering the corridor, the registered vessels receive the recommended entry-time and group speed. Note that the times are selected as to follow the MSCHOA recommendations (transit the most dangerous areas at night), however, the speeds can differ significantly from the static group speeds (i.e. the speed of the group is determined by the slowest vessel).

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Results

The results are depicted on the following picture. The dashed lines symbolize the current scheme, the different coloring of bins symbolizes the optimal grouping scheme.

 Optimal Grouping for 5 groups.

The following table shows comparisons of different grouping schemes with the current scheme.

scheme Speed Level [Knots] saved time/vessel savings/year nr. of groups
current {10,12,14,16,18} 0 min 0 days 10.73
optimal 5 {10,12.2,14,15.4,17} 7 min 97 days 9.16
optimal 6 {10,11.7,13.3,14.6,16,17.6} 31 min 430 days 9.88
dynamic -- 56 min 778 days 12.14

Our simulation results show that noticeable improvements can be achieved by simply optimizing the number and spacing of speed levels. Further significant improvements should be possible if fixed schedule group transit is replaced by the dynamic, demand-responsive transit grouping.

Publications

Papers

  • Ondrej Vanek and Ondrej Hrstka and Michal Pechoucek: Improving Group Transit Schemes to Minimize Negative Effects of Maritime Piracy. IEEE Intelligent Transportation Systems (to appear). 2014.
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  • Ondrej Vanek and Michal Pechoucek: Dynamic Group Transit Scheme for Corridor Transit. In Proceedings of the 5th International Conference on Modeling, Simulation and Applied Optimization (ICMSAO). IEEE Press, 2013.
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  • Ondrej Vanek and Michal Jakob and Ondrej Hrstka and Michal Pechoucek: Agent-based Model of Mariime Traffic in Piracy-affected Waters. Transportation Research Part C: Emerging Technologies.. 2013, vol. 36, p. 157–176. ISSN 0968-090X.
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  • Michal Jakob and Ondrej Vanek and Ondrej Hrstka and Michal Pechoucek: Agents vs. Pirates: Multi-Agent Simulation and Optimization to Fight Maritime Piracy. In 12th International Conference on Autonomous Agents and Multiagent Systems. 2012.
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  • Ondrej Vanek: Security Games with Mobile Patrollers (Extended Abstract). In Proceedings of 10th International Conference on Autonomous Agents and Multiagent Systems (AAMAS). 2011.
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  • Ondrej Vanek, Michal Pechoucek, Michal Jakob, Branislav Bosansky a Viliam Lisy: Agentni simulaci proti somalskym piratum. Scientific American, Czech Edition. 2011.
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  • Ondrej Vanek, Michal Jakob, Ondrej Hrstka, and Michal Pechoucek: AgentC: Agent-based System for Securing Maritime Transit (Demonstration). In Proceedings of The 10th International Conference on Autonomous Agents and Multiagent Systems. 2011.
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  • Ondrej Vanek and Michal Jakob and Viliam Lisy and Branislav Bosansky and Michal Pechoucek: Iterative Game-theoretic Route Selection for Hostile Area Transit and Patrolling. In Tenth International Conference on Autonomous Agents and Multiagent Systems. 2011.
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  • Michal Jakob and Ondrej Vanek and Michal Pechoucek: Using Agents to Improve International Maritime Transport Security. IEEE Intelligent Systems. 2011, vol. 26, p. 90-96. ISSN 1541-1672.
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  • Ondrej Hrstka and Ondrej Vanek: Optimizing Group Transit in the Gulf of Aden. In Proceedings of 15th International Student Conference on Electrical Engineering (POSTER). 2011.
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  • Branislav Bosansky, Viliam Lisy, Michal Jakob and Michal Pechoucek: Computing Time-Dependent Policies for Patrolling Games with Mobile Targets. Tenth International Conference on Autonomous Agents and Multiagent Systems. 2011.
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  • Ondrej Vanek and Branislav Bosansky and Michal Jakob and Michal Pechoucek: Transiting Areas Patrolled by a Mobile Adversary. In Proceedings of 2010 IEEE Conference on Compuattional Intelligence and Games. 2010.
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  • Michal Jakob and Ondrej Vanek and Stepan Urban and Petr Benda and Michal Pechoucek: Employing Agents to Improve the Security of International Maritime Transport. In Proceedings of AAMAS 2010 Workshop on Agents In Traffic and Transportation. 2010.
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  • Stepan Urban and Michal Jakob and Michal Pechoucek: Probabilistic modeling of mobile agents' trajectories. In Proceedings of the International Workshop on Agents and Data Mining Interaction (ADMI 2010). 2010.
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  • Michal Jakob and Ondrej Vanek and Stepan Urban and Petr Benda and Michal Pechoucek: AgentC: Agent-based Testbed for Adversarial Modeling and Reasoning in the Maritime Domain (Demo). In Proceedings of The Ninth International Conference on Autonomous Agents and Multiagent Systems. 2010.
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  • Ondrej Vanek: Agent-based Simulation of the Maritime Domain. In POSTER 2010, 14th International Student Conference on Electrical Engineering. CVUT, Fakulta elektrotechnicka, 2010.
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  • Ondrej Vanek: Agent-based Simulation of the Maritime Domain. Acta Polytechnica. 2010, vol. 50, p. 94-99.
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Books

  • Ondrej Vanek and Michal Jakob and Michal Pechoucek: Using Data-Driven Simulation for Analysis of Maritime Piracy. In Prediction and Recognition of Piracy Efforts Using Collaborative Human-Centric Information Systems. IOS Press, 2013, p. 109-116.
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Other

  • Ondrej Vanek: Computational Methods for Transportation Security. . 2013.
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  • Ondrej Vanek, Michal Jakob, Ondrej Hrstka, and Michal Pechoucek: Agent-based System for Securing Maritime Transit (May 2011). . 2011.
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Reports

  • Michal Jakob and Ondrej Vanek and Branislav Bosansky and Ondrej Hrstka and Vojtech Krizek and Stepan Urban and Petr Benda and Michal Pechoucek: Adversarial Modeling and Reasoning in the Maritime Domain - Year 2 Report. . 2010.
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  • Michal Jakob and Ondrej Vanek and Stepan Urban and Petr Benda and Michal Pechoucek: Adversarial Modeling and Reasoning in the Maritime Domain (Year 1 Report). . 2009.
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