ACKNOWLEDGMENT
This research was carried out by the financial support of Directorate of Research and Community Service (DP2M) Directorate general of Higher Education, Ministry of National Education, Republic of Indonesia through Research Grant “Hibah Penelitian Hibah Bersaing” in the fiscal year 2008 with Number of Contract: 233/SP2H/PP/DP2M/III/2008, in 12th March 2008, All the contribution are acknowledged