Operational research is a science that studies decision-making problems. It mainly studies how to make the best decision through scientific methods and techniques under limited resources. The research objects of operational research mainly include the following aspects:

1. Decision-making Problems: Operations Research mainly studies various decision-making problems, including production planning, logistics management, project management, resource allocation, etc.

2. Mathematical model: operational research mainly describes and solves decision-making problems by establishing mathematical models. These models usually include linear programming, integer programming, nonlinear programming, dynamic programming, network optimization and so on.

3. Algorithms: Operations Research also studies how to solve these mathematical models, including various optimization algorithms, heuristic algorithms and meta-heuristic algorithms.

4. Software tools: operational research also studies how to use computer software tools to solve practical decision-making problems, including various operational research software and data analysis software.

Operational research is widely used, covering almost all economic and social activities. The following are some major application areas:

1. production and manufacturing: operational research can be used to optimize production planning, inventory management, quality control, etc.

2. Logistics and supply chain management: operational research can be used to optimize logistics path, scheduling strategy, inventory management, etc.

3. Project management: Operational research can be used to optimize project schedule, resource allocation and risk management.

4. Finance and investment: operational research can be used to optimize investment portfolio, risk management, asset pricing, etc.

5. Energy and environment: operational research can be used to optimize energy supply, environmental protection, waste treatment, etc.

6. Transportation: Operational research can be used to optimize traffic flow, route selection and transportation mode selection.

7. Health care: Operational research can be used to optimize the allocation of medical resources, disease prevention, medical service quality, etc.

8. Military and national defense: operational research can be used to optimize troop deployment, tactical strategy, weapon system design, etc.