Laboratories for Information Technology, 21 Heng Mui Keng Terrace, Singapore 119613, Singapore. jinyan@lit.a-star.edu.sg|Laboratories for Information Technology, 21 Heng Mui Keng Terrace, Singapore 119613, Singapore. jinyan@lit.a-star.edu.sg|Laboratories for Information Technology, 21 Heng Mui Keng Terrace, Singapore 119613, Singapore. jinyan@lit.a-star.edu.sg|Laboratories for Information Technology, 21 Heng Mui Keng Terrace, Singapore 119613, Singapore. jinyan@lit.a-star.edu.sg|Laboratories for Information Technology, 21 Heng Mui Keng Terrace, Singapore 119613, Singapore. jinyan@lit.a-star.edu.sg