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Model Construction An OR model is an abstract representation of an existing problem situation. It can be in the form of a graph or chart, but mostly, an OR model consists of a set of mathematical relationship. In OR terminology, these are called objective function and constraints.
Model Solution
Once models are constructed, they are solved using the OR techniques, presented in the next section. Actually it is difficult to separate model construction and solution in most cases, since OR technique usually applies to a specific type of model. Thus, the model type and solution method are both part of the OR technique.
Implementation of Results
The results of an OR technique are information which helps in making a decision. The beauty of OR process lies in obtaining, the results which are implement able or we call it a feasible whole exercise will go waste.
OR is an On-going Process
Once the five steps described above are completed, it does not necessarily mean that OR process is completed. The model results and the decisions based on the results provide feedback to the original model. The original OR model can be modified to test different conditions and decisions that might occur in the future. The results may indicate that a different problem exists that had not been thought of previously, thus the original model is altered or reconstructed. As such, the OR process is continuous rather than simply consisting of one solution to one problem.
Operations Research Techniques:
Two of the five steps of OR process, model construction and solution, encompass the actual use of OR techniques. These techniques can be loosely classified into five categories.
Linear mathematical programming technique consist of first, identifying problem as being solvable by linear programming; second formulation of unturned problem and then finding the solution by using established mathematical techniques. It derives its name from the fact that the functional relationship in the mathematical model are linear and the solution techniques consists of a predetermined mathematical steps i.e. program.
Probabilistic techniques covers those problem in which all parameters are not known with certainty. The solution results are assumed to be known with uncertainty, with probability that other solution might exist.
Inventory techniques are specifically designed for the analysis of inventory problem frequently encountered by the business firms. This particular business function is singled out for attention, since it typically represents a significant area of cost for almost every business. This category is divided into probabilistic and deterministic techniques.
Network techniques consist of models that are represented by diagrams rather than strictly mathematical relationship i.e. pictorial representation of the system under consideration. These models can represent either probabilistic or deterministic systems.
Other techniques consist of all the remaining techniques, which do not come under the four heads mentioned above. For example, Dynamic programming employs a different modeling and solution logic than linear programming. In non-
2) Sectoral Planning:
OR can also be employed in a particular sector of the Economy, e.g. in agriculture, in finance, in industry, in marketing, in production, in management etc.
a) Scheduling all operations within a sector can be done by using OR e.g. production scheduling + Distribution planning + marketing + Personnel management + maintenance + ...............
b) Schedule of some operations within a sector can be done by employing OR e.g. Inventory planning in agriculture or distribution of fertilizer etc.
3) Micro Economic Planning:
This sort of activity involve for example: Planning the operations of a Company. Improving the layout of a workshop in a company. Finding size of a hospital in an area etc.
There is a great potential for utilizing OR in this area of planning in our country.
POTENTIAL AREAS OF APPLICATIONS
As mentioned earlier OR can be applied in every field of life. Here are few of the many fields where OR has potential application. This list is by no means comprehensive or exhaustive but definitely will provide an idea of the power of OR as a separate discipline.
Operations Research in the Public Sector
Federal, Provincial and Local Government
Development of Country Structure Plans
Manpower Planning and Career Development in Govt. Departments Organization of Long-Term planning groups at the National Level Corporate Planning in Local Government Allocation of Government Houses Estimation of Future Requirement of School/College Building Placing of Fire Brigade in a City Measuring the Effectiveness of Police Timetabling in Schools and Colleges for Efficient use of Space
Health Management policies for 120-bed nursing units Optimum size of general hospitals Appointment systems for hospital outpatients Stock control for regional and area health units National and area planning of health services Manpower planning for nurses, radiographers, etc. Commissioning of a new general hospital Simulation of pathology laboratories Organizing an ambulance service Care provided by community nurses
Defense Arms control and disarmament studies Communications network development Logistic support in operations Field experimentation War games and other models of battle Equipment procurement Reinforcement and redeployment problems
Operations Research in Industry & Commerce
Finance and Investment
Personnel Personnel shift planning Manpower planning Manpower for an assembly line Effects of flexible working hours
Distribution Distribution of Products. Returnable bottles: how many? Refinery crude tank capacity Depot location of pharmaceutical products Trucking policy for dairy products Distribution of newspapers to newsagents
OR in Transport
Rail Rail freight management Required fleet size of locomotives and rolling stock Forecasting passenger traffic Planning reconstruction of main-line termini Introduction of freightliners
Road Designing urban road networks Forecasts of car ownership Implementation of bus lanes Re-routing bus services Purchasing and maintenance of buses Introduction of flat-fare buses Bus services in rural areas Preparation of crew rosters
Air
Planning the introduction of Boeing 737/Airbus 300 Allocation of aircraft and crew to routes Location of Islamabad Airport Karachi-Lahore - Islamabad - Peshawer: aircraft requirements
Sea Potential traffic for new container services Shipbuilding requirement in the 1990's Optimum ship size for given routes Construction and management of a container terminal
EXAMPLE
Before proceeding further let us take an example, which will help to understand the scope of application in various activities. Given below are some of the major activities which
OPERATIONS:
Oil production from fields
Transportation of Crude
๏ from fields to refineries ๏ from fields to export ports (Jetties) ๏ from import ports (Jetties) to refineries
- Storage of Crude
๏ on fields ๏ at Ports ๏ at refineries
- Refinery Scheduling
Normally, there is a tendency of management to give false information, in order to create a better image, and sometime there may be a lack of adequate communication between OR practitioner and management. To meet these circumstances there should be a healthy interaction with the statistical machinery so as to enhance the quality and availability of data.
Satisfactory power of computer machinery along with associated support should be available so as to analyze the data and forecast correctly. For this management should be aware of modern techniques and tools of management.
Last but not the least management should be ready to accept the change and be enthusiastic to know the correct alternatives.
CONCLUSION
In the proceeding paras we traced briefly the history of OR; defined OR, and its process; elaborated various techniques of OR; identified various areas of application and requirements for successfully applying OR. Before concluding it will be most appropriate to quote Stafford Beer, the famous OR Scientists.
"We call that work operational (with a large O) because it is based in the world of genuine activity, the places where things actually happen. All good sciences, as distinguished from all mysticism is found in empiricism. It involves actual observation, actual measurement and actual experiment."
We call our work Research (with a capital R) because we deal with problems to which no one knows the answer.
"Doing that thing is called RESEARCH!"
Finally I would say,
"We need OR teams of outstanding abilities, working on problems of decision & control at the National Level. Because these problems are usually discussed in economic terms, they are currently assumed to be purely economic problems." BUT THEY ARE NOT
"Interdisciplinary Scientific teams are needed to evaluate issues subject to conflicting criteria."
