Chen, StephenMontgomery, James2013-05-022013-05-02June 20-23Chen, S. & Montgomery, J. (2013). Particle swarm optimization with thresheld convergence. Paper to be presented at IEEE Congress on Evolutionary Computation (CEC2013), June 20-23, 2013, Cancun, Mexico.9781479904549http://hdl.handle.net/1885/9936Many heuristic search techniques have concurrent processes of exploration and exploitation. In particle swarm optimization, an improved 'pbest' position can represent a new more promising region of the search space (exploration) or a better solution within the current region (exploitation). The latter can interfere with the former since the identification of a new more promising region depends on finding a (random) solution in that region which is better than the current 'pbest'. Ideally, every sampled solution will have the same relative fitness with respect to its nearby local optimum – finding the best region to exploit then becomes the problem of finding the best random solution. However, a locally optimized solution from a poor region of the search space can be better than a random solution from a good region of the search space. Since exploitation can interfere with subsequent/concurrent exploration, it should be prevented during the early stages of the search process. In thresheld convergence, early exploitation is “held” back by a threshold function. Experiments show that the addition of thresheld convergence to particle swarm optimization can lead to large performance improvements in multi-modal search spaces.7 pageshttp://www.ieee.org/publications_standards/publications/rights/ieeecopyrightform.pdf "… Authors and/or their employers shall have the right to post the accepted version of IEEE-copyrighted articles on their own personal servers or the servers of their institutions or employers without permission from IEEE, provided that the posted version includes a prominently displayed IEEE copyright notice and, when published, a full citation to the original IEEE publication, including a link to the article abstract in IEEEXplore. Authors shall not post the final, published versions of their papers." From January 2011, "the following copyright notice must be displayed on the initial screen displaying IEEE copyrighted material": "© 20xx IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works." - from publisher web site (as at 2/5/13)particle swarm optimizationthresheld convergencenichingcrowdingexplorationexploitationmulti-modal optimization201310.1109/CEC.2013.65576112015-12-10