Considerable research during the last two decades has concentrated on aggregate production planning: Supply Chain Analytics Case Study, RMIT, Singapore

Introduction

Considerable research during the last two decades has concentrated on aggregate production planning, inventory control, and scheduling. Aggregate planning procedures, which have been proposed for both manufacturing and service organizations, help determine monthly  (or quarterly) output, inventory, and manpower aggregates.

Inventory and scheduling procedures, using the aggregate decisions as input, tend to focus on such short–term decisions as (i) the sizing and timing of production (purchase) orders for specific items, (ii) sequencing of individual jobs (orders), and (iii) short–term allocations of resources to individual activities and operations. The total process of going from aggregate plans to more detailed plans can be called disaggregation.

Depending upon the nature of the production system, disaggregation decisions in a manufacturing organization may exist on one or more of the following three levels:

1. Given aggregate decisions on output and capacity, determine the timing and sizing of specific final product production quantities over the time horizon (sometimes referred to as a master schedule).

2. Given the timing and sizing of final product production quantities, determine the timing and sizing of manufactured (or purchased) component quantities.

Disaggregation problems in service organizations possess the complicating characteristics of stringent response time requirements, time-dependent demand rates, and no finished goods inventories to smooth production rates. Disaggregation decisions in service organizations also exist at three levels:

1. Given aggregate decisions on output and capacity, allocate manpower and other resources to specific operations over the time horizon (sometimes referred to as the staff sizing problem).

2. Given the allocation of resources to specific operations, determine the shift schedules and crew assignments of employees.

3. Given the shift schedule assignments, determine short-term adaptations, reallocations between operations, and priorities of the service requirements.

The right half of Figure 1 provides a basis for describing disaggregation problems in service organizations.