Institute of Information Science, Academia Sinica, Taipei 115, Taiwan, ROC. chunnan@iis.sinica.edu.tw <chunnan@iis.sinica.edu.tw>|Institute of Information Science, Academia Sinica, Taipei 115, Taiwan, ROC. chunnan@iis.sinica.edu.tw <chunnan@iis.sinica.edu.tw>|Institute of Information Science, Academia Sinica, Taipei 115, Taiwan, ROC. chunnan@iis.sinica.edu.tw <chunnan@iis.sinica.edu.tw>|Institute of Information Science, Academia Sinica, Taipei 115, Taiwan, ROC. chunnan@iis.sinica.edu.tw <chunnan@iis.sinica.edu.tw>|Institute of Information Science, Academia Sinica, Taipei 115, Taiwan, ROC. chunnan@iis.sinica.edu.tw <chunnan@iis.sinica.edu.tw>|Institute of Information Science, Academia Sinica, Taipei 115, Taiwan, ROC. chunnan@iis.sinica.edu.tw <chunnan@iis.sinica.edu.tw>|Institute of Information Science, Academia Sinica, Taipei 115, Taiwan, ROC. chunnan@iis.sinica.edu.tw <chunnan@iis.sinica.edu.tw>|Institute of Information Science, Academia Sinica, Taipei 115, Taiwan, ROC. chunnan@iis.sinica.edu.tw <chunnan@iis.sinica.edu.tw>|Institute of Information Science, Academia Sinica, Taipei 115, Taiwan, ROC. chunnan@iis.sinica.edu.tw <chunnan@iis.sinica.edu.tw>|Institute of Information Science, Academia Sinica, Taipei 115, Taiwan, ROC. chunnan@iis.sinica.edu.tw <chunnan@iis.sinica.edu.tw>|Institute of Information Science, Academia Sinica, Taipei 115, Taiwan, ROC. chunnan@iis.sinica.edu.tw <chunnan@iis.sinica.edu.tw>|Institute of Information Science, Academia Sinica, Taipei 115, Taiwan, ROC. chunnan@iis.sinica.edu.tw <chunnan@iis.sinica.edu.tw>|Institute of Information Science, Academia Sinica, Taipei 115, Taiwan, ROC. chunnan@iis.sinica.edu.tw <chunnan@iis.sinica.edu.tw>|Institute of Information Science, Academia Sinica, Taipei 115, Taiwan, ROC. chunnan@iis.sinica.edu.tw <chunnan@iis.sinica.edu.tw>|Institute of Information Science, Academia Sinica, Taipei 115, Taiwan, ROC. chunnan@iis.sinica.edu.tw <chunnan@iis.sinica.edu.tw>|Institute of Information Science, Academia Sinica, Taipei 115, Taiwan, ROC. chunnan@iis.sinica.edu.tw <chunnan@iis.sinica.edu.tw>|Institute of Information Science, Academia Sinica, Taipei 115, Taiwan, ROC. chunnan@iis.sinica.edu.tw <chunnan@iis.sinica.edu.tw>|Institute of Information Science, Academia Sinica, Taipei 115, Taiwan, ROC. chunnan@iis.sinica.edu.tw <chunnan@iis.sinica.edu.tw>|Institute of Information Science, Academia Sinica, Taipei 115, Taiwan, ROC. chunnan@iis.sinica.edu.tw <chunnan@iis.sinica.edu.tw>