30. The LP Model Minimize t (L t w t + h t u t + f t v t + c t i t + a t b t ) s.t. u t - v t = w t – w t-1 for each period t : workforce change p t w t + i t-1 - i t + b t – b t-1 = d t for each period t: demand balance i T= =0, b T = 0 for last period T; closing out w t , u t , v t , i t , b t 0 for each time period t: nonnegativity