?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adissertation&rft.aulast=Shelya+Putri+Nurhaliza+Abdillah&rft.aufirst=-&rft.au=Shelya+Putri+Nurhaliza+Abdillah%2C+-&rft.degree=S1&rft.inst=Universitas+Pendidikan+Indonesia&rft.date=22+July+2025&rft.title=OPTIMIZATION+OF+EMPLOYEE+CERTIFICATION+SYSTEM+UI+USING+USER+CENTERED+DESIGN+MODEL