Institute of Research and Community Outreach Petra Christian University Jl. Siwalankerto 121-131 Surabaya 60236 Indonesia Phone : +62-31-2983139, 2983147 Fax : +62-31-8436418, 8492562 E-mail : jurnal_informatika@petra.ac.id Homepage : http://puslit2.petra.ac.id/ejournal