
Operations research defines as a mathematical method of problem-solving and decision-making in the organization.
Operational Research helps decision making in Manufacturing industries, Hydraulics & Piping Engineering, Airlines, Health Services, Game theory, etc.
These analytical methods help us to make better decisions and problem-solving skills.
Linear programming, transportation cases, queuing theory, job shop scheduling, sequencing model, break-even analysis are some analytical methods of decision making.
Furthermore, Graphical, simplex, Big-M are some mathematical methods in linear programming.
Operational researchers faced with a new problem must determine which of these techniques are most appropriate given the nature of the system.

Applications of OR
- Scheduling (of airlines, trains, buses, etc.)
- Assignment (assigning crew to flights, trains or buses; employees to projects; commitment and dispatch of power generation facilities)
- Facility location (deciding the most appropriate location for new facilities such as warehouse; factory or fire station)
- Hydraulics & Piping Engineering (managing flow of water from reservoirs)
- Health Services (information and supply chain management)
- Game Theory (identifying, understanding; developing strategies adopted by companies)
- Urban Design
- Computer Network Engineering (packet routing; timing; analysis)
- Telecom & Data Communication Engineering (packet routing; timing; analysis)

As per the journal Operations Research, The major sub-disciplines in modern operational research are;
- Computing and information technologies
- Financial engineering
- Manufacturing
- Service sciences
- Supply chain management
- Policy modeling and public sector work
- Revenue management
- Transportation
Resources:
Wikipedia: Operations research