Introduction:
Management deals with reality that is at once complex, dynamic, and multifaceted. It is neither possible nor desirable, to consider each and every element of reality before deciding the courses of action. It is impossible because of time available to decide the courses of action and the resources, which are limited in nature. More over in many cases, it will be impossible for a manager to conduct experiment in real environment.
Definition:
We can “define an operations research model as some sort of mathematical or theoretical description of various variables of a system representing some aspects of a problem on some subject of interest or inquiry. The model enables to conduct a number of experiment involving theoretical subjective manipulations to find some optimum solution to the problem on hand”.
Classification of Models
The models we use in operations research may broadly classify as:
1. Mathematical and Descriptive models
2. Static and Dynamic Models
Mathematical and Descriptive Models
Descriptive Model
1. A descriptive model explains or gives a description of the system giving various variables, constraints and objective of the system or problem.
2. The drawback of this model is as we go on reading and proceed; it is very difficult to remember about the variables and constraints, in case the problem or description of the system is lengthy one.
3. It is practically impossible to keep on reading, as the manager has to decide the course of action to be taken timely. Hence these models, though necessary to understand the system, have limited use as far as operations research is concerned.
Mathematical Model
1. We have identified the variables and constraints and objective in the problem statement and given them mathematical symbols x and y and a model is built in the form of an inequality of ≤ type. Objective function is also given. This is exactly a mathematical model, which explains the entire system in mathematical language, and enables the operations research person to proceed towards solution.
