Fatal error: Uncaught Error: Class "DataObject" not found in /home/aake8592/subdomains/jurnal.aakpekalongan.ac.id/lib/pkp/classes/announcement/AnnouncementType.inc.php:17 Stack trace: #0 {main} thrown in /home/aake8592/subdomains/jurnal.aakpekalongan.ac.id/lib/pkp/classes/announcement/AnnouncementType.inc.php on line 17