# Dynamic Agent Prioritisation with Penalties in Distributed Local Search

### Amina Sambo-Magaji, Inés Arana, Hatem Ahriz

#### Abstract

Distributed Constraint Satisfaction Problems (DisCSPs) solving techniques solve problems which are distributed over a number of agents.The distribution of the problem is required due to privacy, security or cost issues and, therefore centralised problem solving is inappropriate. Distributed local search is a framework that solves large combinatorial and optimization problems. For large problems it is often faster than distributed systematic search methods. However, local search techniques are unable to detect unsolvability and have the propensity of getting stuck at local optima. Several strategies such as weights on constraints, penalties on values and probability have been used to escape local optima. In this paper, we present an approach for escaping local optima called Dynamic Agent Prioritisation and Penalties (DynAPP) which combines penalties on variable values and dynamic variable prioritisation for the resolution of distributed constraint satisfaction problems. Empirical evaluation with instances of random, meeting scheduling and graph colouring problems have shown that this approach solved more problems in less time at the phase transition when compared with some state of the art algorithms. Further evaluation of the DynAPP approach on iteration-bounded optimisation problems showed that DynAPP is competitive.

#### References

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#### Paper Citation

#### in Harvard Style

Sambo-Magaji A., Arana I. and Ahriz H. (2013). **Dynamic Agent Prioritisation with Penalties in Distributed Local Search** . In *Proceedings of the 5th International Conference on Agents and Artificial Intelligence - Volume 1: ICAART,* ISBN 978-989-8565-38-9, pages 276-281. DOI: 10.5220/0004259202760281

#### in Bibtex Style

@conference{icaart13,

author={Amina Sambo-Magaji and Inés Arana and Hatem Ahriz},

title={Dynamic Agent Prioritisation with Penalties in Distributed Local Search},

booktitle={Proceedings of the 5th International Conference on Agents and Artificial Intelligence - Volume 1: ICAART,},

year={2013},

pages={276-281},

publisher={SciTePress},

organization={INSTICC},

doi={10.5220/0004259202760281},

isbn={978-989-8565-38-9},

}

#### in EndNote Style

TY - CONF

JO - Proceedings of the 5th International Conference on Agents and Artificial Intelligence - Volume 1: ICAART,

TI - Dynamic Agent Prioritisation with Penalties in Distributed Local Search

SN - 978-989-8565-38-9

AU - Sambo-Magaji A.

AU - Arana I.

AU - Ahriz H.

PY - 2013

SP - 276

EP - 281

DO - 10.5220/0004259202760281