Overview of the Operations Research Modeling Approach:preparing to apply the model

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preparing to apply the model

What happens after the testing phase has been completed and an acceptable model has been developed? If the model is to be used repeatedly, the next step is to install a well-documented system for applying the model as prescribed by management. This system will include the model, solution procedure (including postoptimality analysis), and operating procedures for implementation. Then, even as personnel changes, the system can be called on at regular intervals to provide a specific numerical solution.

This system usually is computer-based. In fact, a considerable number of computer pro- grams often need to be used and integrated. Databases and management information systems may provide up-to-date input for the model each time it is used, in which case interface pro- grams are needed. After a solution procedure (another program) is applied to the model, additional computer programs may trigger the implementation of the results automatically. In other cases, an interactive computer-based system called a decision support system is installed to help managers use data and models to support (rather than replace) their decision making as needed. Another program may generate managerial reports (in the language of management) that interpret the output of the model and its implications for application.

In major OR studies, several months (or longer) may be required to develop, test, and install this computer system. Part of this effort involves developing and implementing a process for maintaining the system throughout its future use. As conditions change over time, this process should modify the computer system (including the model) accordingly.

Example. The application vignette in Sec. 2.2 described an OR study done for Continental Airlines that led to the formulation of a huge mathematical model for reassigning crews to flights when schedule disruptions occur. Because the model needs to be applied immediately when a disruption occurs, a decision support system called CrewSolver was developed to incorporate both the model and a huge in-memory data store representing current operations. CrewSolver enables a crew coordinator to input data about the schedule disruption and then to use a graphical user interface to request an immediate solution for how to reassign crews to flights. (Also see Selected References A4 and A6 for other examples where a decision support system played a vital role in an award-winning OR application.)

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