MODELING POVERTY SEVERITY INDEX IN EASTERN INDONESIA BASED ON NONPARARAMETRIC SPLINE TRUNCATED APPROACH FOR PANEL DATA - Amelia, Dita; Suliyanto, Suliyanto; Aldawiyah, Najwa Khoir; Siagian, Kimberly Maserati; Suryono, Nadinta Kasih Amalia; Trisa, Nadya Lovita Hana (BAREKENG: Jurnal Ilmu Matematika dan Terapan, 2026)