Hierarchical planning

The concept of successive planning is to decompose the overall decision problem into smaller subproblems and to tackle each of these with a suitable solution methodology. This decomposition often follows the principals of hierarchical planning, as most practical problems can be structured hierarchically. In the area of supply chain management, the so-called supply chain planning matrix is an... 

In Section 11.4.5, we have already seen that the SNP optimizer is restricted to plan in the SNP horizon. If campaign production problems are solved in the context of hierarchical planning it is important that the SNP optimizer respects setup operations of PP/DS orders in the overlap of the SNP and PP/DS horizon. This... 

Planned orders are place holders for process orders that have yet to be checked for planning feasibility by detailed scheduling. In a hierarchical planning model they are interpreted as a hint to the details planner that they should create and schedule a process order. They are often the result of an automated MRP (material requirements planning) run that is based on planned independent requirements and does not consider resource capacities. 

To integrate an organizational unit that uses multipurpose batch plants into the company, IT infrastructure with its ERP system, a hierarchical planning approach is most often used. Starting from a material requirements planning (MRP) run, capacity requirements are determined and roughly checked, although the check of the capacity requirements is not directly combined with the material requirements. 

The challenge in supply planning is that specifically the available production quantities per month can depend on the schedule of the products on a specific resource if change-overs consume significant time so that the overall capacity error in die rough-cut master plan would not be acceptable. Therefore, supply network planning includes also the aspect of hierarchical planning, where production quantities based on a discrete monthly... 

While the model of abstract refinement is quite satisfactory for the hierarchical planning of the process synthesis methodology, it is quite cumbersome and possibly incorrect as a model to describe the intricate web of design actions from one milestone to the next. Instead, the transformational model (Balzer et al., 1976 Scherlis and Scott, 1983 Stephanopoulos, 1989) provides a more appropriate vehicle. This model converts specifications into designs through a series of correctness-... 

The overall design methodology was modeled as a hierarchical planning process. It starts with project specifications, goes through a predefined set of intermediate design milestones, and ends with a number of design alternatives. 

ES-EPA (Expert System for Environmental Pollutant Analysis) is an expert system for producing laboratory test plans, including the appropriate sampling methods, pretreatments, test methods and their order. ES-EPA generates test plans in a stepwise manner from abstract plans called "templates" to detailed plans, using a hierarchical planning mechanism. The knowledge base contains information on analysis items, test methods, test equipment, pretreatments and other necessary information. The prototype system has been successfully tested for various cases in the domain. The development of a delivery version has been completed and it will soon be used in the field on a daily basis to further verify its feasibility. 

In order to have multiple representations of a plan with different abstraction levels, a hierarchical planning mechanism is necessary. The method is first to sketch a plan that is complete but vague and then gradually refine the vague parts into more detailed sub-plans until the plan consists of a complete sequence of detailed components (Z) ... 

A simplified schematic of the hierarchical planning mechanism of ES-EPA is shown in Figure 2. There are four representations of a plan with different abstraction levels Level 1, 2, 3 and 4. In this figure, the rectangular boxes represent specific tasks that can not be expanded any further, and boxes with rounded corners represent abstract components. 

On Level 4, all the abstract components are expanded into specific task components. The hierarchical planning mechanism stops on this level. Then rules for detailed modification are applied to the plan. Certain components might be added or deleted after the application of these rules. 

The top level hierarchical plan becomes the input for the next level of planning, which is the master production schedule (MPS) or master schedule level. This schedule is always prepared in terms of end items (i.e., what is shipped from the factory or plant). If the factory produces bicycles, then the end item is a bicycle. But, if the factory produces front wheels for another factory that assembles them onto frames, then the end item is the front wheel. Planning for the MPS is constrained by the earlier planning which resulted in the production plan. Remember that the production plan was developed in terms of product families. The MPS is very specific about the end item. For example, the production plan for an apparel factory may have scheduled 200 dozen men s long sleeve shirts for the month of January. The production plan did not specify color or design, just the family of shirts that would be produced. The MPS might then divide up these 200 dozen into specific end items to be produced in specific time periods. This is illustrated in Figure 9.3 for the month of January. Note that the shirts that are scheduled to be produced in all of the weeks of January total the 200 dozen scheduled to be produced in January. 

Ozdamar, L. and T. Yazgac, A Hierarchical Planning Approach for a Production-Distribution System , International Journal of Production Research, 37 (1999), 3759-3772. 

Deterministic, backlog not allowed in the aggregate model A hierarchical planning approach proposed... 

Fox, M. D. Long (1995). Hierarchical planning using abstraction. lEE Control Theory and Applications. 

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