Institute of Statistical Science, Academia Sinica, Taipei, Taiwan. gshieh@stat.sinica.edu.tw|Institute of Statistical Science, Academia Sinica, Taipei, Taiwan. gshieh@stat.sinica.edu.tw|Institute of Statistical Science, Academia Sinica, Taipei, Taiwan. gshieh@stat.sinica.edu.tw|Institute of Statistical Science, Academia Sinica, Taipei, Taiwan. gshieh@stat.sinica.edu.tw|Institute of Statistical Science, Academia Sinica, Taipei, Taiwan. gshieh@stat.sinica.edu.tw|Institute of Statistical Science, Academia Sinica, Taipei, Taiwan. gshieh@stat.sinica.edu.tw|Institute of Statistical Science, Academia Sinica, Taipei, Taiwan. gshieh@stat.sinica.edu.tw