The original meaning of operational research is operational research, operational research, operational research, operational research, which translates into operational research. It borrows the word "Shu" from "A Thousand Miles of Strategies" in Historical Records, which not only shows its military origin, but also shows that it has already sprouted in China. As a modern science, operational research was first introduced to Britain and the United States during the Second World War. Some scholars describe operational research as a scientific means to make decisions on various operations of organizational systems. In their groundbreaking works, P.M.Morse and G.E.Kimball defined operational research as: "Operational research belongs to the field of management, and uses mathematical methods to make overall plans for problems that need to be managed. An applied science to make decisions. " Another founder of operations research defines operations research as "a scientific method that people who manage systems must use to obtain the optimal solution about system operation." It uses many mathematical tools (including probability statistics, mathematical analysis, linear algebra, etc. ) and logical judgment method to study the organization and management, planning and scheduling of people, money and things in the system. In order to maximize the benefits, the origin of modern operational research can be traced back to decades ago, and scientific means were first tried in the management of some organizations. However, it is generally believed that the activities of operational research began with military tasks in the early days of World War II. At that time, there was an urgent need to effectively allocate scarce resources to various military operations and activities in each operation. Therefore, the United States and later the United States military management authorities called on a large number of scientists to deal with strategic and tactical issues by scientific means. In fact, this requires them to study various (military) actions. These groups of scientists are the earliest operation teams. During the Second World War, OR successfully solved many important operational problems, showing the great material power of science. It paved the way for the later development of OR. When the post-war industry resumed its prosperity, people realized that these problems were basically similar to those faced in the war, but the actual environment was different. Because of the increasing complexity and specialization in the organization, operational research sneaked into industrial and commercial enterprises and other departments. Since 1950s, it has been widely used. With the in-depth research and application of the application mechanism of system configuration, aggregation, decentralization and competition, a set of relatively complete theories has been formed, such as planning theory, queuing theory, storage theory and decision theory. Due to the maturity of its theory and the advent of electronic computers, it has greatly promoted the development of operational research, and many countries in the world have established specialized societies specializing in this field and related activities. On 1952, the United States established the Institute of Operations Research and published the magazine of Operations Research. Other countries in the world have also established operational research societies and periodicals, and established the International Association of Operational Research in 1957. The characteristics of operational research are: 1. Operational research has been widely used in the overall coordination of industrial and commercial enterprises, military departments, civil affairs and other research institutions, so 2. Operational research not only carries out creative scientific research on various operations, but also involves the actual management of organizations. It has strong practicability, and should eventually provide constructive suggestions to decision makers and receive practical results; 3. It aims at overall optimization, and tries to solve the conflict of interests among all departments of the system in the best way from the perspective of the system. It can also be regarded as an optimization technology, which provides an optimization method to solve various problems. The research methods of operational research are: 1. Extract essential elements from real life situations to construct mathematical models, so as to seek mathematical models. 2. Explore the structure of the solution and deduce the solution process of the system; 3. Seek the optimal solution of the system from the feasible scheme. The specific contents of operational research include: planning theory (including linear programming, nonlinear programming, integer programming and dynamic programming), graph theory, decision theory, game theory, queuing theory, storage theory, reliability theory and so on. Mathematical programming, that is, the above planning theory, is an important branch of operational research. As early as 1939, H.B.Kahtopob of the Soviet Union and F.L.Hitchcock of the United States first studied and applied linear programming methods in production organization management and transportation planning. 1947, Danziger and others put forward the simplex method for solving linear programming problems, which laid the foundation for linear programming theory and calculation. In particular, the emergence and perfection of electronic computers have made the planning theory develop rapidly. From the optimization of solving technical problems to the departments of industry, agriculture, commerce, transportation and decision analysis, thousands of large-scale linear programming problems with constraints and variables can be handled by computers. From the scope, it can be as small as a team's planning arrangement, as large as the whole department, and even the optimization scheme analysis of the national economic plan. All of them are useful, with strong adaptability, wide application and relatively simple calculation technology. The basic work of nonlinear programming was completed by H.W. Kuhn and A.W. Tucker in 195 1 year. By 1970s, mathematical programming was not only in theory, but also in method. It has further developed in the depth and breadth of application. Graph theory is an ancient and very active branch, which is the basis of network technology. The founder of graph theory is mathematician Euler. 1736, he published his first paper on graph theory, which solved the famous problem of the Seven Bridges in Konigsberg. After a hundred years, Kirchhoff first applied graph theory to analyze the power grid in 1847. Thus, graph theory was introduced into the field of engineering technology. Since 1950s, graph theory has been further developed. Using graphs to describe complex and huge engineering systems and management problems can solve many optimization problems in engineering design and management decision-making, such as the shortest time and the shortest distance to complete engineering tasks. The lowest cost, etc. Graph theory has been paid more and more attention by mathematics, engineering technology and management. Queuing theory is also called stochastic service system theory. After 1909, the queuing problem of Danish telephone engineer A.K.Erlang began to be studied in a more general way, and some important achievements were made. 1996 began the research on machine management, land and air transportation and so on. After 195 1 year, the theoretical work has made new progress and gradually laid the theoretical foundation of modern random service system. Queuing theory mainly studies various parameters of various systems, such as queuing length, queuing waiting time, provided services, etc. In order to get better service, it is a theory to study the random aggregation and dispersion of the system. Reliability theory is a theory that studies system faults to improve system reliability. The systems studied by reliability theory are generally divided into two categories: (1) unrepairable systems, such as missiles, whose parameters are life and reliability; (2) The important parameter of repairable systems, such as general mechanical and electrical equipment, is effectiveness. Its value is the ratio of system normal working time to normal working time plus accident repair time. Decision theory studies decision-making problems. The so-called decision-making is the process of choosing the best scheme scientifically with the help of certain theories, methods and tools according to objective possibilities. Decision-making problem consists of decision-maker and decision-making domain. Decision domain consists of decision space, state space and result function. The science of studying decision theory and method is decision science. The problems to be solved in decision-making are various, and there are different classification methods from different angles. According to the determination of the natural state faced by decision makers, it can be divided into deterministic decision-making, risky decision-making and decision-making under uncertainty. According to the number of objectives on which decisions are based, they can be divided into: single-objective decision-making and multi-objective decision-making; According to the nature of decision-making problems, it can be divided into: strategic decision-making and strategic decision-making, and various types of decision-making problems according to different standards. Different decision-making methods should be adopted for different types of decision-making problems. The basic steps of decision-making are: (1) determine the problem and put forward the decision-making goal; (2) Discover, explore and draw up various feasible schemes; (3) Choose the most satisfactory scheme from various feasible schemes; (4) the implementation and feedback of the decision, in order to seek the dynamic optimization of the decision. If the other side of the decision maker is also a person (a person or a group of people), and both sides want to win, this competitive decision is called game decision. The three basic elements that constitute a game problem are: player, strategy and the gain and loss of a game. At present, game problems can be generally divided into finite zero-sum two-person game, position game, continuous game, multiplayer game and differential game. Operational research is a hard subject in soft science, which has the properties of logical mathematics and mathematical logic, and is the basic theory and sum of systems engineering and modern management science.