Department of Applied Mathematics and Institute of Statistics, National Chung Hsing University, Taichung 402, Taiwan.|Department of Applied Mathematics and Institute of Statistics, National Chung Hsing University, Taichung 402, Taiwan.|Department of Applied Mathematics and Institute of Statistics, National Chung Hsing University, Taichung 402, Taiwan.|Department of Applied Mathematics and Institute of Statistics, National Chung Hsing University, Taichung 402, Taiwan.|Department of Applied Mathematics and Institute of Statistics, National Chung Hsing University, Taichung 402, Taiwan.|Department of Applied Mathematics and Institute of Statistics, National Chung Hsing University, Taichung 402, Taiwan.