Optimalisasi penatausahaan dan pengendalian persediaan logistik bencana alam pada Direktorat Perlindungan Sosial Korban Bencana Alam (PSKBA) dengan pendekatan Soft System Methodology (SSM) = Optimization of administration and control of natural logistic disaster inventory at the Directorate of Social Protection for Natural Disaster Victims (PSKBA) with the Soft System Methodology (SSM) approach