7.5 VVT COST, TIME AND RISK OPTIMIZATION
As mentioned before, it is virtually impossible to carry out a complete VVT process due to resource constraints, chiefly time and money. Nevertheless, once we can estimate the cost, time and risk of system VVT and model the process mathematically, we can provide VVT engineers and organizations in general with a tool to select a VVT strategy for specific business objectives.
Operations Research (OR) (i.e., optimization theory and practice) based on mathematical programming is a well-established field described in hundreds of books and thousands of articles. In their book, Avriel and Golany (1996) have bridged the gap between the theory of mathematical programming and the real-world practice of industrial engineering. This reference text presents issues in linear, integer, multiobjective, stochastic, network and dynamic programming.
7.5.1 Optimizing the VVT Process
Single-Objective Optimization Problems
According to Avriel and Golany (1996), any Single Objective Optimization Problem (SOOP) is composed of three basic ingredients: (1) an objective function, which we want to minimize or maximize, (2) unknowns or variables, which affect the value of the objective function, and (3) constraints that permit the unknowns to take on certain values but exclude others.
The optimization problem then is: Find values of the variables that minimize or maximize the objective function while satisfying the constraints. For example, in choosing to optimize ...