\input zb-basic \input zb-ioport \iteman{io-port 05730556} \itemau{Zhang, Junqi; Liu, Kun; Tan, Ying} \itemti{KNOB particle swarm optimizer.} \itemso{Tan, Ying (ed.) et al., Advances in swarm intelligence. First international conference, ICSI 2010, Beijing, China, June 12--15, 2010, Proceedings, Part I. Berlin: Springer (ISBN 978-3-642-13494-4/pbk). Lecture Notes in Computer Science 6145, 78-85 (2010).} \itemab Summary: It is not trivial to tune the swarm behavior just by parameter setting because of the randomness, complexity and dynamic involved in particle swarm optimizer (PSO). Hundreds of variants in the literature of last decade, brought various mechanism or ideas, sometimes also from outside of the traditional metaheuristics field, to tune the swarm behavior. While, in the same time, additional parameters have to be afforded. This paper proposes a new mechanism, named KNOB, to directly tune the swarm behavior through parameter setting of PSO. KNOB is defined as the first principal component of the statistical probability sequence of exploration and exploitation allocation along the search process. The using of the KNOB to tune PSO by parameter setting is realized through a statistical mapping, between the parameter set and the KNOB, learned by a radial basis function neural network (RBFNN) simulation model. In this way, KNOB provides an easy way to tune PSO directly by its parameter setting. A simple application of KNOB to promote is presented to verify the mechanism of KNOB. \itemrv{~} \itemcc{} \itemut{Particle Swarm Optimizer; Exploitation; Exploration; search Strategy; KNOB} \itemli{doi:10.1007/978-3-642-13495-1\_10} \end