Heuristic allocation

Since scope economies are especially hard to quantify, a separate class of optimization models solely dealing with plant loading decisions can be found. For example, Mazzola and Schantz (1997) propose a non-linear mixed integer program that combines a fixed cost charge for each plant-product allocation, a fixed capacity consumption to reflect plant setup and a non-linear capacity-consumption function of the total product portfolio allocated to the plant. To develop the capacity consumption function the authors build product families with similar processing requirements and consider effects from intra- and inter-product family interactions. Based on a linear relaxation the authors explore both tabu-search heuristics and branch-and-bound algorithms to obtain solutions. 

Solution construction and Evaluation module-. Each ant constructs a solution in two stages. In the h stage, an ant, at each construction step, allocates an operation of a p>articular job to one of its available resources. The ants use a probabilistic choice rule which is a function of the pheromone trail Tyy(fn) and a heuristic information based on processing time. Ant z chooses to allocate operation Oy to the route r with a probability given by... 

Heuristics are used to bind the operations to functional unit instances, and a clique partitioning algorithm is used to allocate and bind registers. Finally, multiplexors and interconnections are added in a straight-forward manner, and optimized using a set of interconnect transformations. 

First, an ASAP schedule is constructed, assuming infinite resources, and one cycle per operation. Then optimizations are applied, moving operations to other control steps to reduce the maximum number of operations of each type in any one control step, and grouping operations into functional units so as to have a minimum number of functional units. Uien the scheduler traverses the control step schedule, passing the operations in each control step to the data path allocator. The data path allocator tries to bind those operations using heuristics if it fails, the scheduler tries to delay operations until later control steps, and if that also fails, the user is notified that the resource constraints should be increased. 

In the case of dynamic allocation, there is an additional requirement to consider how these heuristics apply to the same functions but in different situations for example, a task could conceivably be repetitive and monotonous in one situation but encourage a feeling of usefulness in another. 

The final step is to interrogate the TAFEI diagram by creating a transition matrix. All possible states are entered as headers, as shown in Table 7.3. The cells represent state transitions (e.g., the cell at row 1, column 2 represents the transition between state 1 and state 2). With support from the allocation heuristics and CWA-based... 

Undertake and analyze allocations— With this, and any mandatory assignments and heuristics (such as those already present in BS 11064-1 2001 or those presented in the next section) in mind, the analyst should work through the task analysis and annotate each higher level goal or subgoal as follows ... 

In BS/EN/ISO 11064-1 2001 preliminary function allocations are performed using an overview approach comprised of four basic heuristics. Human factors best practice offers an extension to this approach in the form of Fitts List (Fitts, 1951). The expanded collection of heuristics is anchored around information-processing stages and the relative performance of humans or automation in performing them. Fitts List is shown in Table 7.4. 

The first example reflects human factors best practice by illustrating the use of a freely available HTA tool. This tool enables many of the basic requirements of BS/ EN/ISO 11064-1 2001 to be met, including the definition of task requirements, using the outputs of the HTA, combined with heuristics, in order to perform a preliminary allocation of function, then going further to help meet the requirements for job design. 

From the diagram, it is clear that the heuristics driving these allocation decisions are sensitive to the situations in which functions are occurring for example, in steady-state operation perhaps the automation can be relied upon to make systan operators aware of potential faults. In these conditions, it might be sufQdent for human operators to be relatively passive receptors and to have information pushed onto them however, in abnormal situations, it might be necessary to augment this function with human attributes. Rather than being passive receptors of information. 

Ramirez-Marquez, X. Coit, D.W., 2004. A heuristic for solving the redundancy allocation problem for multistate series-parallel systems. Reliability Engineering System Safety, 83(3) 341-349. 

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