Department of Computer Science, National Tsing Hua University, Hsinchu, Taiwan.|Department of Computer Science, National Tsing Hua University, Hsinchu, Taiwan.|Department of Computer Science, National Tsing Hua University, Hsinchu, Taiwan.|Department of Computer Science, National Tsing Hua University, Hsinchu, Taiwan.|Department of Computer Science, National Tsing Hua University, Hsinchu, Taiwan.|Department of Computer Science, National Tsing Hua University, Hsinchu, Taiwan.