Two heuristics based on branch and bound (B&B) are developed to solve closed-loop material requirements planning (MRP) lot-sizing problems that have general product structures and variable costs. A “look ahead method'’(LAM) heuristic allows for variable production/purchasing costs and uses a...

The four dimensional space-time paradigm is cohesive and inclusive, and better identifies the major constraints on goods and/or services production. It is intended to analyze and synthesize both the similarities and differences among industries and companies positioned in matrix categories, and...