Department of Computer Science, National Tsing Hua University, Hsinchu, Taiwan 300, Republic of China.|Department of Computer Science, National Tsing Hua University, Hsinchu, Taiwan 300, Republic of China.|Department of Computer Science, National Tsing Hua University, Hsinchu, Taiwan 300, Republic of China.|Department of Computer Science, National Tsing Hua University, Hsinchu, Taiwan 300, Republic of China.|Department of Computer Science, National Tsing Hua University, Hsinchu, Taiwan 300, Republic of China.|Department of Computer Science, National Tsing Hua University, Hsinchu, Taiwan 300, Republic of China.|Department of Computer Science, National Tsing Hua University, Hsinchu, Taiwan 300, Republic of China.