Institute of Information Science, Academia Sinica, NanKang 115, Taipei, Taiwan, Republic of China.|Institute of Information Science, Academia Sinica, NanKang 115, Taipei, Taiwan, Republic of China.|Institute of Information Science, Academia Sinica, NanKang 115, Taipei, Taiwan, Republic of China.|Institute of Information Science, Academia Sinica, NanKang 115, Taipei, Taiwan, Republic of China.|Institute of Information Science, Academia Sinica, NanKang 115, Taipei, Taiwan, Republic of China.|Institute of Information Science, Academia Sinica, NanKang 115, Taipei, Taiwan, Republic of China.