F. A. Zaini, Sulaima, M., I. A. W. A. Razak and A. N. F Ali 2023. INVESTIGATION OF OPTIMAL OFF-PEAK TARIFF RIDER (OPTR) BY USING PARTICLE SWARM OPTIMIZATION FOR SELECTED COMMERCIAL AND INDUSTRIAL CONSUMERS IN MALAYSIA. Journal of Engineering and Technology (JET). 14, 1 (Jun. 2023), 137–157.