N. Nuraini (1), E. Soewono (2), K.A. Sidarto (3) (1) Industrial and Financial Mathematics Research Group, Faculty of Mathematics and Nat-
ural Sciences, Institut Teknologi Bandung, Bandung 40132, Indonesia., Indonesia,
(2) Industrial and Financial Mathematics Research Group, Faculty of Mathematics and Nat-
ural Sciences, Institut Teknologi Bandung, Bandung 40132, Indonesia., Indonesia,
(3) Industrial and Financial Mathematics Research Group, Faculty of Mathematics and Nat-
ural Sciences, Institut Teknologi Bandung, Bandung 40132, Indonesia., Indonesia