Development and Application of Systems Science and Systems Engineering

YU Jingyuan, LI Ming, YU Weishu

1 China Aerospace Academy of Systems Science and Engineering, Beijing 100048

Abstract: Systems science and systems engineering, as a new science and technology domain in modern science and technology, is developing rapidly, and showing greater and greater vitality. QIAN Xuesen is recognized as the pioneer and founder of systems science and systems engineering in China. His whole innovation process from systems thinking to systems practice has made pioneering contributions at different levels from engineering, technology, science to philosophy. These achievements and contributions have very important scient ific value and practical sign ificance.

Presenting QIAN Xuesen’s contribution in systems science and practice, this paper elaborates the development and application of systems science and systems engineering.

Key words: systems science, systems engineering, systemism

1 INTRODUCTOIN

First, let’s look at systems science and systems engineering from the perspective of the overall development of modern science and technology in order to understand some characteristics of systems science and systems engineering and its relationship with other science and technology.

From the perspective of the development trend and characteristics of modern science and technology, the following major aspects are closely related to the emergence and development of systems science and systems engineering.

First, the development of modern science and technology presents two obvious trends, i.e. high differentiation and high comprehensiveness. On one hand, the existing disciplines and fields are more and more subdivided, and new disciplines and fields are constantly emerging. On the other hand, different disciplines and fields intersect, combine and merge with each other, and develop towards the meta-synthesis which complement each other and promote each other. From this development trend, systems science and systems engineering is the science and technology in this latter development trend.

Second, the rise of complexity science has attracted great attention at home and abroad. In the middle of 1980s, complexity research appeared abroad. Complexity research and complexity science go in hand with the trend of high integration and have a close relationship with systems science.

One of the founders of complexity science and Nobel Prize laureate Gell-Mann wrote in his bookThe Quark and the Jaguarthat “research has shown that physics, biology, behavioral science, and even art and anthropology can be linked together in a new way. Some facts and ideas may seem irrelevant at first, but new methods can easily link them up”. Gell-Mann did not say what this new approach and method is, but from later research on complex systems and complex adaptive systems, it can be seen that this new approach is the systems approach and this new method is the systems method. The so-called complexity is actually system complexity.

Third is the development of scient ific methodology. During the development from latter-day science to modern science,scientific methodology has experienced reductionism, holism and then systemism, dialetical unity of reductionism and holism.Systemism method is closely related to the emergence and development of systems science.

Fourth, the modern information revolution with computer,network and communication as its core has brought about changes in the way of thinking of human beings, resulting in the systems thinking featuring human-machine combined, humannetwork combined and human-dominated. This way of thinking makes human beings more intelligent and capable of understanding and dealing with more complex things. This systems thinking mode also provides a theoretical and technical basis for the systemism method and its application.

Fifth is the transformation of innovation mode. From individualoriented innovation to group-oriented innovation, the innovation mode and innovation system featuring that of human-machine combined, human-network combined and human-dominated have emerged. Especially the national innovation system has become a powerful driving force for innovation-driven development.

Sixth, modern social practice is more and more complex.The more complex the social practice, the more comprehensive and systematic it is. Social practice is a systems practice as well as a systems engineering, so systems science and systems engineering are even more needed.

QIAN Xuesen’s thinking on systems science and system of systems science collectively reflect the above characteristics.

2 SYSTEMS SCIENCE AND SYSTEMISM

Great achievements have been made in modern science and technology. QIAN Xuesen pointed out that today mankind is studying and exploring the objective world that consists of five levels, i.e. ultra-microcosmic, microcosmic, macrocosmic, cosmoscopic and swelling-cosmic. Among them, the macrocosmic level is the Earth where we live. Life and organisms appeared on the Earth, and then came mankind and human society.

Disciplines and fields are generated when we study different problems in the objective world from different angles. The objective world as a whole features mutual connection, interaction and in fluence. Thus, the science and technology reflect objective laws of different fields and levels in the objective world which are also knowledge systems featuring mutual connection,interaction and in fluence. (See Figure1)

Figure 1 Five levels of the objective world

There is no systems science among the sciences as seen in Figure 1, but it is the development of these sciences that nurtures and generates systems science.

QIAN Xuesen pointed out that the emergence of systems science is a scient ific revolution, which is a leap for mankind in understanding the objective world. So, what is studied in systems science? Why is systems science so important?

From the point of view of dialectical materialism, things in the objective world are universally connected, “the world is a whole, featuring universal connection, and there is a relationship of mutual influence, interaction and restriction among all elements within anything and between things”. There must be objective laws since objective things are a whole, with universal connection, that we should study, understand and apply.

The most basic and important concept that can reflect and summarize the objective fact and essential feature of the universal connection of objective things is the system. The so-called system refers to a whole which is composed of interrelated,interacting and mutually in fluenced components and has certain functions. The system thus summarized and de fined is ubiquitous in the objective world, which includes nature, society and human beings.

Based on the systems thinking and combined with the development of modern science and technology, QIAN Xuesen clearly pointed out that “systems science studies the objective world from the perspective of the whole and part, the local and the global, as well as the hierarchical relationship of things”. That is, it studies the objective world from the perspective of systems, which are the basic object of the research and application of systems science.

Natural science studies the objective world from the perspective of material, material structure and material movement;social science studies the objective world from the perspective of human beings, human society and their development. Systems science is different from natural science and social science,but it has a profound inner connection with them. Systems science can connect the problems studied in natural science, social science and other fields as a system to conduct comprehensive,systematic and holistic research. This is why systems science has the characteristics of intersectionality, comprehensiveness and integrity. It is also these characteristics that make systems science the meta-synthesis of modern science and technology development and becomes a new science and technology domain in the modern science and technology system.

System structure, system environment and system function are three important basic concepts of the system. System structure refers to the inside of the system (system components and their relationship), and system environment refers to the outside of the system. The most important characteristics of the system is that as a whole it has properties not found in its components, which is the integrity of the system, and the external reflection of system integrity is the system function.

The integrity of the system means that we should attach great importance to the system as a whole. Recognition of the parts does not mean the recognition of the whole system.System integrity is not a simple addition of its component properties, but the results emerging from the system as a whole,which are reflected in emergence mechanism and laws.

The system research shows that the system structure, system environment, and the relationship between them determine the integrity and function of the system. This is a very important system law, and also the core issue of system research and application.

Theoretically speaking, studying how the system structure and environment determine the integrity and function of the system and revealing the general laws of system existence, evolution, coordination, control and development has become the basic task of systematology, especially complex giant systematology. The study on complexity abroad is essentially the exploration in system integrity, that is, the exploration in systematology.

On the other hand, from the application point of view, according to the above system principles, in order to make the system have the desired functions, especially the best functions,we can change and adjust the system structure or system environment and the relationship between them. However, the system environment generally cannot be changed arbitrarily,and can only be adapted voluntarily if it cannot be changed.However, the structure can be organized, adjusted, changed and designed.

Thus, we can coordinate and unify the whole and parts of the system with the environment by organizing, changing, and adjusting the relationship between the system components,hierarchies, and system environment, to make them coordinate with each other, creating the desired and best functions in the system as a whole. This is the basic connotation of system control, system management and system intervention. It is an applied theoretical problem to be studied by such disciplines as system management and system control, and it is also the main goal to be achieved by systems engineering and control engineering.

From the perspective of scient ific and technological development and engineering practice, science is the knowledge of understanding the world, technology is the knowledge of transforming the world, and engineering is the practice of transforming the objective world. From this point of view, after hundreds of years of development, natural science has three levels of knowledge structure, namely, basic science (basic theory), technological science (applied science) and engineering technology(applied technology). Like natural science, systems science also has three levels of knowledge structure.

The three levels of knowledge in the systems science system established by QIAN Xuesen are as follows.

First, systems engineering is at the level of engineering technology or application technology. It is the engineering technology directly used to transform the objective world. Unlike other engineering technologies, it is the technology of organizing and managing system.

Second, operations research, cybernetics and information theory are at the level of technological science, directly providing theoretical methods for systems engineering.

Third, systematology and complex giant systematic are at the level of basic science, revealing the objective system laws.

The establishment of this system is of great signi ficance to the development and application of systems science. At present,there is no such clear and rigorous systems science architecture abroad.

While establishing the systems science system, QIAN Xuesen also put forward the systemism. Systemism lies between philosophy and science and is a bridge between systems science and dialectical materialism. On one hand, dialectical materialism guides the research of systems science through systemism. On the other hand, the development of systems science has enriched and developed the philosophy of dialectical materialism through the re finement of systematology.

As for systemism, QIAN Xuesen clearly pointed out that “the systemism we advocate is neither holism nor reductionism, but the dialectical unity of holism and reductionism”.

According to the thought of systemism, we should first focus on the system as a whole in terms of system issues. In addition,we should also attach importance to the system components and unify the whole and part dialectically, and finally study and solve the problem as a whole. This goes beyond reductionism and develops holism, and is the advantage of systemism.

Using systemism to study and cognize the systems, reveal the objective laws of systems and establish systematic knowledge systems is the essence of systematic epistemology. From this perspective, the establishment of system of systems science is the embodiment of systematic epistemology.

To sum up, systems thinking is the philosophical content of dialectical materialism. The establishment of systemism and system of systems science makes systems thinking develop from a philosophical thought basis to a systematic science system. The system of systems science is the embodiment of the systems thinking at different levels from engineering, technology, science and philosophy. It enables the systems thinking established upon science. Philosophy and science are united, and practice and scientific theory are united, thus QIAN Xuesen’s thinking on systems science formed. QIAN Xuesen’s thinking on systems science is an important development and enrichment for systems thinking of dialectical materialism.

3 COMPLEX GIANT SYSTEMS AND SYSTEMATIC METHODOLOGY

In systems science, systems engineering has been applied and made remarkable achievements to fields such as in space systems engineering. In technological science, operations research, cybernetics and information theory have formed their own theories and methods. However, systematology, especially systematology on complex giant systems, first proposed by QIAN Xuesen, are emerging disciplines to be set up.

In the middle of 1980s, QIAN Xuesen started the “Systematology Seminar” to establish systematology. He participated in all academic activities of the seminar during the seven years from 1986 to 1992 and, continued the study on systematology in the manner of “small seminars”.

He put forward a new categorization of systems based on the complexity of system structure and classified systems into simple, simple giant, complex, complex giant and special complex giant systems in the seminar. For example, creatures,the human body, human brain, social, geographical and galaxy systems are complex giant systems, among with which the social system is most complex and is also called a special complex giant system. All the systems are open and have exchanges of materials, energy and information with the external environment, they are so called open complex giant systems.

QIAN Xuesen spec ifically de fined though the seminars that systematology is a science studying the general law of system structure and functions (system evolution, coordination and control). It has established the basic framework of systematology with simple, simple giant, complex, complex giant and special complex giant systems (the social system) as the main line, formed the main research contents of systematology, put forward the methodology and methods of the study on systematology, laid a foundation and indicated its research direction.

Simple and simple giant systems have had their corresponding methodology and methods as well as theories, i.e. selforganization theory. However, complex, complex giant and social systems require new methodology and methods because the existing ones are not applicable. Therefore, the study on complex giant systems is called complex giant systematology.

Natural science is called “exact science” because it uses the research methods that from qualitative to quantitative in the process of development from latter-day science to modern science. Social science and theory on literature and art are called“descriptive sciences” because they use the speculative and descriptive methods that from qualitative to qualitative in the research of more complicated issues. Such trend is also changing with the development of science and technology. Some disciplines are gradually developing towards exactness, such as economics and sociology.

From the perspective of methodology, the methods of reductionism has played an important role in the development process. In particular, great success has been made in the field of natural science.

In the methods of reductionism, the object of study is decomposed into parts and it is deemed that the whole will be clear as long as its parts are studied clearly. If it fails to study its parts clearly, it will be decomposed deeper for study until it is made clear.

Based on this methodology, physics studies material structure at the quark level and biology and life sciences study life at the gene level. This is undoubtedly a great achievement made in the modern science and technology.

However, the truth is that we cannot explain the macrostructure with the knowledge of elementary particles or answer what life is with the knowledge of gene. Such facts make scientists aware that “de ficiencies of reductionism become increasingly apparent” (1999,Science).

That is, methods of reductionism decomposed the whole into parts for more detailed studies, which is its advantage.However, reductionism cannot deal with high-level and integrity-related questions, which is its disadvantage. Therefore, only focusing on parts and relying on reductionism is not enough. It is required to deal with the integrity-related problem, i.e. the so-called “emergence” issue in the study of complexity.

LI Zhengdao, a famous physicist, once talked about the development of physics in the 21st century, “I guess that the direction in the 21st century is integrity and uniformity. The elementary particles of microcosmic will be combined with the vacuum structure and large quantum states of macrocosmic. These will probably be the research objectives in the 21st century”.

To combine macrocosmic and microcosmic is to study how macrocosmic emerges from microcosmic. To solve the integrity-related problem is to establish an access path from microcosmic to macrocosmic and unify them.

At the same time, methods of reductionism cannot deal with the integrity issues of systems, especially complex, complex giant and social systems. From the perspective of systems, the decompose of systems into parts and study of single parts will cut off the relations with other parts. In this way, integrity issues of systems cannot be solved even if each part is studied clearly.

Bertalanffy, a biological scientist, was aware of this from an early period. In his words, when biological study has developed to molecular biology, the more of biology we understand at the molecular level, the vaguer our knowledge of biology as a whole will be. In such a case, he put forward a general systemism in 1940s, which was in fact holism, emphasizing the study of issues on the whole of creature system. Limited by the contemporary level of science and technology, a specific method system supporting the holism had not been developed. The study was still carried out at the whole and qualitative level.Fundamental problems could not be solved. As QIAN Xuesen mentioned, “the general systemism has been at the stage of conceptual explanation over decades. There are few specific theories and quantitative results”. However, the proposal of holism is indeed an important contribution to the development of modern science and technology.

The study of complexity occurred overseas in the middle of 1980s. As to complexity, QIAN Xuesen pointed out that “Issues that may not or should not be handled with the methods or methodology of reductionism currently shall or should be handled with new scientific methods are complexity issues.Complex giant systems are such issues”.

Integrity issues of systems, especially those of complex,complex giant and social systems, are complexity issues. Foreign scientists “used the term ‘complex systems’ in the study of complexity to represent systems that their properties cannot be explained with the understanding of their parts.” (1999,Science).

Foreign studies on complexity and complex systems are indeed innovative in terms of research methods, such as genetic and evolutionary algorithms, swarm software platforms, agentbased system modeling, art ificial life and society described with agent.

In terms of methodology, although the limitation of reductionism is well known, a new one has not been proposed. The methodology and methods are two issues at different levels.Methodology refers to the approach and research route to be followed in the study of issues. Spec ific methods are involved under the guidance of the methodology. If the methodology is inappropriate, fundamental problems cannot be solved even with the best method. Therefore, the methodology is more fundamental and important.

As mentioned above, QIAN Xuesen put forward the idea that systemism was the dialectical unity of holism and reductionism. Based on this idea, QIAN Xuesen proposed to unify the methods of reductionism and the methods of holism dialectically and established the methods of systemism.

In the application of the methods of systemism, the whole system is decomposed into parts, and then the studies on parts are integrated into the whole so as to realize the overall emergence of systems and finally study and solve issues on the whole.

The methods of systemism have absorbed the strong points from the methods of reductionism and holism, while making up for their respective limitations, surpassing the methods of reductionism and developing the methods of holism. This is the systematic methodology unifying the whole and the parts dialectically to study and solve system issues. This was a contribution of milestone sign ificance made by QIAN Xuesen to the scient ific methodology, which has greatly promoted the development of systems science and inevitably made a profound impact on other domains of science and technology such as natural science and social science.

QIAN Xuesen proposed the systematology methodology,as well as its method system and application mode.

He proposed the method of “meta-synthesis from qualitative to quantitative” and its practical form, “the Hall for Workshop of Meta-synthetic Engineering (HWME) from qualitative to quantitative”, which are collectively called the method of metasynthesis, based on the development of modern information technologies at the end of 1980s and the beginning of 1990s and called the application agency the Overall Design Department. In this way, the methods of systemism were materialized and a set of operable, effective methods system and application mode were developed.

QIAN Xuesen pointed out that HWME was a research platform integrating the following successful experiences, as well as scient ific and technological achievements:

1. Experience of seminars over decades;

2. Method of meta-synthesis from qualitative to quantitative analysis;

3. c3I and battle simulation;

4. Intelligence information technology;

5. Art ificial intelligence;

6. Virtual reality technology;

7. Intelligence system combining human and machine;

8. Systematology;

9. Other information technologies in the information revolution, such as network technology.

At the level of methods and technologies, it is both metasynthesis method and technology that integrated information,knowledge and wisdom with human-machine combined,human-network combined and human-dominated. At the level of application, it is meta-synthetic engineering with the Overall Design Department as the entity.

The essence of meta-synthesis is to combine the expert system, data, information and knowledge system and computer system, establishing a highly intelligent human-machine combined and integrated system.

The system has advantages in comprehensiveness, integrity,intelligence and wisdom. It integrates human thinking, achievements of thinking, experience, knowledge, human wisdom and various kinds of intelligence, data and information, realizing quantitative understanding from qualitative understanding in multiple aspects.

The human-machine combined and human-dominated way of systems thinking put forward by QIAN Xuesen is the theoretical foundation of the method of meta-synthesis. From the perspective of noetic science, both the human brain and computers may process information effectively, but they have great differences.

As to how the human brain thinks, QIAN Xuesen said, “logical thinking is a microcosmic method; imagery thinking is a macrocosmic method; creative thinking combines the microcosmic and macrocosmic methods. Creative thinking is the source of wisdom. Logical thinking and imagery thinking are means”.

Now, computers can indeed do many things even better and faster than the human brain from the logical thinking perspective. They are good at processing information rapidly and accurately. Many scient ific achievements have proved it, such as the mechanical theorem validated by the famous mathematician WU Wenjun and the current development of artificial intelligence.

However, computers can do little in terms of imagery thinking. They are greatly inferior to the human brain. So creative thinking can only rely on the human brain.

Since computers have advantages in logical thinking, the human-machine combined and human-dominated way of thinking will have greater ability. Its intelligence, wisdom and creativity will be stronger than those of the human brain and machines.This is also the systems principle of 1+1＞ 2, which reflects the way of systems thinking. (See Figure 2)

According to Figure 2, the human-machine combined,human-dominated way of thinking is at the highest end in terms of intelligence, wisdom and creativity. The emergence of such a wise man indicates the future occurrence of “new people”,which is not simply a human being, but “new people” with human-machine combined and human-network combined in the same “new society”. This trend has emerged and is continuing to develop. We should attach great importance to studies on the “new people” and “new society”.

Figure 2 The way of systems thinking

Information, knowledge and wisdom are three issues at different levels. Information is extensive, knowledge is profound and wisdom is high-level. We will not necessarily have knowledge with information or wisdom with information and knowledge. Knowledge may be obtained with the meta-synthesis of information. Wisdom may be achieved with that of information and knowledge. Human beings have been obtaining information, knowledge and wisdom since the beginning of history. Due to the development of computer-dominated modern information technologies, we can now obtain information, knowledge and wisdom in the human-machine combined, human-network combined, and human-dominated way which has advantages over just the human brain. This is progress of milestone sign ificance in the development history for humankind that we should pay great attention to.

The method of meta-synthesis is such a human-machine combined, human-network combined, and human-dominated method for obtaining information, knowledge and wisdom. It is an information processing, knowledge innovation and wisdom integration system with human-machine combined.

As there is a saying of “meta-synthesis” in the traditional Chinese culture, i.e. the comprehensive integration of each aspect of a quite complicated object so as to have understandings of the whole and achieve wisdom through meta-synthesis. QIAN Xuesen called the set of methods “meta-synthetic wisdom engineering”. “The theory of meta-synthetic wisdom” is the theoretical knowledge resulting from the further development of meta-synthetic wisdom engineering and its application.

The method of meta-synthesis can be used for both theoretical and applied studies.

Both theoretical and applied studies of complex, complex giant and social systems are conducted by the Overall Design Department with the method of meta-synthesis according to the systematology methodology.

Qualitative meta-synthesis combines the existing scientific theories, empirical knowledge and information with the judgment of experts (including the knowledge, wisdom and creativity of experts), proposing and constructing empirical hypotheses such as guesses, judgments, ideas, countermeasures and solutions for system issues. Such empirical hypotheses are generally qualitative, the reason is that no rigorous scient ific way is available for proving their correctness or truth.

In natural science and mathematical science, such empirical hypotheses are proved with exact logical reasoning and various experimental measures. Such process manifests the feature of studies from a qualitative nature to a quantitative nature, i.e. the research method of exact science.

In complex, complex giant and social systems, empirical hypotheses of system issues usually cannot be proposed by one expert or even experts in one field because of their characteristics of interdisciplinary, cross-domain and inter-hierarchy. Instead, empirical hypotheses are proposed by the expert system composed of experts in different fields and disciplines based on the knowledge and wisdom of expert groups. This is the reason why the method of meta-synthesis requires an expert system.

However, it is hard to prove their correctness with just the various methods used in natural science and mathematical science alone. For example, some issues in the social and geographical systems cannot be subjected to simple logical reasoning or tests. But empirical hypotheses should not only be described from speculation and qualitative-qualitative, which are common methods in social science and theory on literature and art.

The way for systems science to become an “exact science”is through human-machine combined, human-network combined, and human-dominated way of thinking and research methods. We should allow machines to complete what they can do to the greatest extent and give full play to advantages of computers in logical thinking in terms of adopting the way for cooperation between machines and human.

Wisdom of expert groups as well as scient ific theories and empirical knowledge, qualitative and quantitative knowledge and conceptual and perceptual knowledge in different disciplines and fields finally realize the meta-synthesis from qualitative to quantitative through human-machine interaction, repeated comparison and successive approximation, gaining precise quantitative understandings of systems and then drawing scientific conclusions on the correctness of empirical hypotheses.

Whether empirical hypotheses are true or not, they are a progress in understanding. Then, new empirical hypotheses proposed to continue quantitative studies. This is a cyclic and constantly deepened research process.

The application of the method of meta-synthesis is a research and work mode with the cooperation of expert system and the cooperation between expert system and machine system as well as that of the Overall Design Department.

In summary, it is realized in three steps, i.e. qualitative metasynthesis, qualitative-quantitative combined meta-synthesis and the meta-synthesis from qualitative to quantitative. The process is not separated but cyclic with approached approximation.

Complex, complex giant and social systems issues are generally unstructured. However, current computers can only process structured issues. According to the process of metasynthesis, the method of meta-synthesis is actually to approach unstructured issues with a structured sequence during the approximation.

The schematic diagram for the use of the method of metasynthesis for studies on decision-supporting is shown in Figure 3.

Such a set of methods is effective for processing complex,complex giant and social systems, and its scient ificity and effectiveness have been proved with successful cases.

The theoretical basis of the method of meta-synthesis is the science of thinking. Its methodology and method foundation is systems science and mathematical science. Its technological foundation is the computer-dominated modern information technology and network technology. Its philosophical foundation is the dialectical materialist epistemology and theory on practice.

In terms of methodology and method features, the method of meta-synthesis is in essence the methodology and method used to study inter-disciplinary, cross-domain and inter-hierarchy issues. It will inevitably produce an important impact on the system of systems science at different levels, thus facilitating the overall development of systems science.

QIAN Xuesen proposed to establish the science and technology of complex giant systems in the middle of 1990s.

The method of meta-synthesis allows the establishment of the theory of complex giant systems at the scientific level,i.e. the systemism of meta-synthesis, which is subordinated to theory on complex giant systematology. The general theory has not been fully developed as yet. However, we can establish it gradually with the methodology and methods for studying such systems. This is a new field of science.

At the technological level, the method of meta-synthesis may be applied for the development of technologies of complex giant systems, i.e. system technologies of meta-synthesis,especially technologies for the organization and management of complex giant systems, thus greatly facilitating the development of systems engineering.

Systems engineering is a technology for organizing and managing systems as well as the technology and method for their planning, study, design, realization, test and use. It was first applied in engineering systems, such as aerospace systems engineering.

The organizing and managing issues of complex giant and social systems cannot be handled by using just the engineering systems engineering, which is its limitation. In this case, the method of systems engineering needs to be developed. Due to the availability of the method of meta-synthesis, systems engineering may be used to organize and manage complex giant and social systems.

Therefore, systems engineering, which has developed from engineering systems engineering to complex giant systems engineering and social systems engineering, is a systems engineering technology and method available now for organizing and man-aging complex giant and social systems.

Figure 3 The schematic diagram for the use of the method of meta-synthesis for studies on decision-supporting

The application of systems engineering to different systems should integrate with their different scient ific theories, methods and technologies. For example, the knowledge of social sciences and theory on literature and art is required for the application to social systems.

Based on these features, systems engineering is different from other technologies. It is a holistic technology of coordinating and unifying the whole and the part, and studying and solving system issues as a whole, a system technology of metasynthesis as well as a quantitative technology for global optimization. It is a technology and method for studying and solving system management issues on the whole.

QIAN Xuesen said that “the revolution of systems engineering in organization and management technologies and methods is a technological revolution”. The technological revolution will inevitably result in the revolution of organization and management.

The science and technology of complex giant systems created by QIAN Xuesen is in fact a meta-synthesis system composed of the idea, method, theory (basic theory and applied theory), technology and engineering of meta-synthesis. Therefore, the system of complex giant systems science has been formed, which is philosophically the theory of meta-synthetic wisdom, greatly promoting the system having developed from systems science into complex giant systems science.

The development trends of modern science and technology are highly differentiated and integrated. Systems science and complex giant systems science are the most fundamental and applicable knowledge in the highly integrated development trend. They will inevitably produce a great impact on the development of modern science and technology, especially its development towards meta-synthesis in the 21st century.

4 SYSTEMS ENGINEERING AND THEORY ON SYSTEMS PRACTICE

The thinking on systems science, systemism, system of systems science and complex giant systems science have not only an important scient ific value, but also an important practical signi ficance.

In terms of theory on practice, any social practice, especially complex social practice, is spec ifically purposeful and organized and is highly comprehensive, systematic and dynamic.

Social practice generally includes three important components. First is the object in practice, i.e. what to do, which reflects the purpose of practice. Second is the subject in practice,i.e. who will do it and how to do it, which reflects the organizing in practice. Third is the decision-making body, which decides whether to do it and how to do it.

From the perspective of systems, any social practice is a spec ific practice system. QIAN Xuesen said, “any social activity can form a system, the establishing organizing and effective operating of which will become systems engineering.” The object is a system. The subject is also a system which involves humans.Their combination is also a system. Therefore, social practice is systems practice as well as systems engineering.

Therefore, the organizing, managing and decision-making issues of social practice or engineering become those of systems.It is natural and inevitable to apply thinking on systems science,systemism, theories, methods and technologies of systems science to the organizing, managing and decision-making of social practice or engineering. It reflects a systematic theory on practice. This is the reason why systems science and systems engineering have wide applicability and strong vitality.

But in reality, we have not actually considered and processed the organizing and managing of social practice and engineering from the perspective of systems and used systems engineering to solve problems in various kinds of social practice and engineering.

People call it “systems engineering” when encountering social practice or engineering issues involving many complicated factors and are difficult to process. This has two meanings.First, it is systems practice or engineering as mentioned above from the perspective of practice or engineering. Second, from the perspective of science and technology, since it is systems engineering or practice, it shall be organized and managed with systems engineering technology, as systems engineering is a technology and method directly used to organize and manage systems. Technology and engineering are un ified dialectically and inseparable.

Unfortunately, people often only pay attention to the first meaning which is already an improvement, but pay less attention to the use of systems engineering technology. As a result,issues are all considered as systems engineering, but problems are not solved by systems engineering.

An entity is required to put systems engineering technology into practice. The development of the Chinese space industry has benefited from the successful application of systems engineering technology.

To organize thousands of people and develop high-quality and highly reliable model products with less input in a shorter period of time in large-scale scient ific and technological projects represented by aerospace science and technology such as missiles, satellites and manned space flight, a set of scient ific organizing and managing methods and technologies are required.

In large-scale scient ific and technological projects, there are theoretical issues at the level of science to be studied and solved and high and new technologies at the level of technology to be developed. Meanwhile, such theories and technologies should be applied to engineering practice so as to produce products and realize the industrialization or the diffusion towards other industries, thus promoting the national economic and social development and the national security. In essence, scient ific innovation, technological innovation, product innovation and even industrial innovation are integrated organically, thus realizing the innovation of meta-synthesis.

Such projects are featuring large scale, high input and great influence and are inter-disciplinary, cross-domain, interhierarchy and cross-departmental. Due to the long developing period, parallel development strategies with respective generations for use, development, advanced research and exploration are adopted.

Each model in aerospace systems is an engineering system.In terms of organizing and managing, the managing method of systems engineering with the Overall Design Department and two commanding lines is used. It has been proven in practice that the organizing and managing method is quite effective (see Figure 4).

The object system in practice (the plane I) should be studied and solved on the whole, i.e. to constitute an object system(engineering system) with scient ific and technological achievements with expected functions. This involves the structure,environment and functions of engineering systems. A research entity is required to conduct this work, i.e. the Overall Design Department.

Figure 4 The practice of systems engineering

The Overall Design Department is composed of professionals familiar with each aspect of the object system and led by an expert with extensive knowledge (called the Chief Designer).According to requirements for overall objectives of the system(functions of model system), the Overall Design Department designs an overall scheme for the system and technological approaches for realizing the whole system.

The Overall Design Department develops a model system as a component of the larger system that it is subordinated to and considers all its technological requirements first for realizing the technical coordination of the larger system (the environment of model system). It also designs the system as an entirety with the organic combination of various subsystems and considers technological requirements of each subsystem first for realizing the technical coordination of the whole system (the structure of model system). The Overall Design Department coordinates and resolves con flicts among subsystems and between subsystems and the system in the development first based on requirements for overall objectives (functions of model system).

It analyzes, demonstrates, designs, coordinates and plans the structure, environment and functions of model engineering system with the system method and the meta-synthesis of theories and technologies of relevant disciplines, coordinates and un ifies the whole and the part and makes an overall scheme, including system modeling, simulation, analysis, optimization, test and assessment with computer and mathematics as tools so as to obtain a satisfying and best overall scheme for the system and provide such an overall scheme for the decision-making department as the scient ific basis for decision making. Once accepted by the decision-making entity, it will be put into practice by the relevant departments.

The Overall Design Department in aerospace model projects has been proved to be quite effective in practice. It has played an important role in the development of Chinese aerospace projects.

On the plane II, a development system should be organized according to the established overall scheme. The system involves scient ific research institutions, colleges, enterprises and international cooperation and requires the input of manpower,material and financial resources. Requirements for the development system include the reasonable and optimal allocation of resources and the development for a reliable and high-quality object system (engineering system) at lower costs and to be achieved in a shorter period of time. Systems engineering is required to organize and manage the system. However, different from the engineering system above, the development system is organized and managed here. The system involves overall issues of system structure, environment and functions as well as issues such as the mechanism.

This system is organized and managed by administrative power in the planned economic system. But the administrative system is not enough in the market economic system. The invisible hand, a market, is also required. The development system is composed of subjects with different interest. How to organize and manage the system well seems more complicated today. This is also what we should innovate and develop.

On the plane III, the engineering system and the development system are combined. This is a dynamic process, involving the organizing, managing and coordinating in terms of the science and technology of engineering system, as well as the subject of the development system. Therefore, two lines are formed, i.e. the technical commanding line led by the Chief Designer and the dispatch commanding line led by the Chief Commander. They are mutually coordinated (see Figure 5).

The object processed by the Overall Design Department above is an engineering system, also called as engineering systems engineering. What’s more, the way of reasonable and optimal allocation of resources in the development system also requires overall design in practice. The engineering and development systems are closely related. A new system is constituted through their combination. The new system also involves the mechanism, development strategies, planning, policies &measures, decision-making and management, etc.

It belongs to the category of social systems that is obviously much more complicated than the object system. Engineering system mainly involves the meta-synthesis of natural science and technology, while the new system requires social sciences and theory on literature and art besides natural science and technology.

How to organize and manage the system well also requires systems engineering. However, engineering systems engineering cannot process the organizing and managing of such systems. Social systems engineering is required instead. An entity is required for the application of social systems engineering,i.e. the Overall Design Department with the application of the method of meta-synthesis mentioned above.

Figure 5 The coordination of engineering system and development system

Different from the Engineering Department of Overall Design of aerospace models, this Overall Design Department has achieved substantial development, but the idea of systems science of studying and solving system management issues on the whole is consistent.

The Overall Design Department studies and solves organizing and managing issues of system practice and engineering with the method of meta-synthesis and the systems engineering technology. That is, it manages systems engineering by coordinating and unifying the whole and components of systems with the environment and solving problems on the whole. It reflects the systems theory on practice.

In 1978, QIAN Xuesen, XU Guozhi and WANG Shouyun published the paperTechnology of Organization and Management: Systems Engineering, greatly promoting the application of systems engineering in each field, particularly promoting social systems engineering applied to the organizing and managing at the national macroscopic level so as to facilitate scientific and democratic decision-making and modernization of organizing and managing.

In October 1991, QIAN Xuesen was given the award of“Scientist with National Outstanding Contributions” by the State Council and the Central Military Commission. He said on the award ceremony, “I think, current science and technology are not simply natural science, technology and engineering, but the whole knowledge system of mankind to understand and transform the objective world. The highest summary of the system is Marxist philosophy. We can establish a scient ific system and use it to solve problems in Chinese socialist construction.”

The scientific system mentioned here includes natural science, social sciences, mathematical science, systems science,noetic science, somatic science, geographical science, military science, behavioral science, architecture science and the theory on literature and art, etc. For the modern scient ific and technological system and the human knowledge system is constituted,see Figure 6.

Figure 6 Knowledge system of human to understand and reform the world

The modern science and technology system and the human knowledge system provide precious knowledge resources and wisdom sources for the national management and construction.We shall fully apply and exploit such knowledge and wisdom so as to achieve the wisdom through meta-synthesis. The method of meta-synthesis and meta-synthetic wisdom engineering in systems science provide us with effective scient ific methods and a strong technical means to achieve the meta-synthetic wisdom.

This is the scient ific and technological foundation of the application of systems science, science on complex giant systems and social systems engineering technology to the organization and management at the national macroscopic level by QIAN Xuesen.

QIAN Xuesen proposed to establish the National Overall Design Department on multiple occasions to apply social systems engineering to the national organization and management,which was highly valued and fully af firmed by the central leaders.

On January 19, 2008, HU Jintao visited QIAN Xuesen and said, “I read your report on systems engineering while studying in the Party School of the CPC at the beginning of 1980s, which made a profound impression on me. Your theory emphasizes that we must pay attention to the whole, consider various factors as a whole and make clear their relations while handling complex issues. This is very creative. Now, we emphasize scient ific development. That is, we should make overall arrangements and pay attention to comprehensive and coordinated development”.

The General Secretary XI Jinping attaches great importance to the top-level design and the overall design.

Some departments in China are somewhat like the Overall Design Department, but they still use traditional research methods. Different from various existing committees of experts, the Overall Design Department is not simply a standing research entity. Moreover, it uses the method of meta-synthesis as its basic research method, serves the decision-making body with its research achievements and plays a supporting role in decisionmaking.

In terms of the modern decision-making system, there is not only the decision execution system, but also the decision supporting system under the decision-making body. The former is based on laws, regulations and power and strives for the high ef ficiency and low costs of decision making and execution. The latter is based on science and strives for scienti fic, democratic and programmed decision-making.

The two systems are different in structure, functions and effect as well as their organization, mechanism and operation, but are also mutually coordinated and collaborative. They complement each other’s advantages and serve the decision-making body jointly. The decision-making body combines them and develops the action and power for transforming the objective world.

In China, most departments unite them as one, meaning one department needs both decision execution and decision support. As a result, neither can be done well and the interests of the departments are increased. If we can establish the system of Overall Design Department and a set of decision-making supporting system, it will be the mechanism and organization& management innovation in terms of decision-making and management. . Its significance and influence will be great and profound.

The management for a project, engineering, unit, department and even a country is of different types of systems. The priority of system management is to study and solve issues on the whole, which had been greatly advocated by QIAN Xuesen. Only in this way can we make overall planning, give play to overall advantages of the system managed, and achieve the effect of 1+1＞ 2. This is the systems engineering management method based on theory on systems practice.

However, departments are separated and only pursue a local optimum but neglect the whole in reality from microcosmic,mesoscopic up to macrocosmic levels. There are issues about the organization and mechanism and interests of individual departments as well as the profound in fluence of the thinking mode of reductionism.

Overall advantages of systems cannot be exerted with such a decentralized management mode based on reductionism. Its best effect is 1+1=2 and even might be 1+1＜2. The latter occurs in most cases.

In conclusion, system of systems science and complex giant systems science manifest systems epistemology, the methods of meta-synthesis and its system manifest systems methodology,and systems engineering manifests theory on systems practice.

QIAN Xuesen’s theory on systemism mainly includes systems epistemology, methodology and theory on systems practice. It is different from the general system theory of Bertalanffy which is also holism. As QIAN Xuesen said, “The theory on systems systemism as we mentioned is not the ‘general system theory’ of Bertalanffy. It is more profound than the latter.”

Systems epistemology and the system of systems science and complex giant systems science reflect QIAN Xuesen’s thought on systems science. Theory on systems practice and systems engineering reflect his thought on systems practice, i.e.systems engineering. Systems methodology and the system of the method of meta-synthesis reflect QIAN Xuesen’s thought on systems meta-synthesis.

Thoughts on systems science, practice and meta-synthesis constitute QIAN Xuesen’s systems thought. QIAN Xuesen’s systems thought has greatly enriched and developed the systems thought of dialectical materialism.

In summary, QIAN Xuesen made pioneering contributions at different levels including engineering, technology, science and philosophy in the whole innovation chain ranging from systems thought to systems practice. Such systematic innovative achievements are unavailable overseas and are advanced, leading and realistic. They are great contributions to the development of modern science and technology, which have extensive and profound in fluence. We shall learn, study and apply them carefully and carry them forward.

In 1995, QIAN Xuesen spec ifically pointed out in the paperWe Shall Study How to Meet the 21st Century, “Systems science is a scient ific revolution emerging in the middle period of this century, while the practice of systems engineering will cause a technical revolution. The scient ific and technical revolution will inevitably trigger a revolution of organization and management in the 21st century.” He further indicated, “Systems science,systems engineering and the Overall Design Department are closely integrated with HWME, thus forming the methodology of studying and solving complexity issues of social systems which is interconnected in science, technology and practice. It has provided scient ific organization and management methods and technologies for the management of modern society and country. Its result will push scient ific, democratic and programmed decision making and management modernization to a new stage.”

5 CONCLUSIONS

Systems science is not simply a science in the 21st century.Meanwhile, systems science and systems engineering will bring an organization and management revolution in the 21st century which will produce extensive and a profound promotional effect on the management of the modernized society and country and have great and profound significance and influence. We shall attach great importance to the development and application of systems science and systems engineering.

General Secretary XI Jinping presided over the second plenary meeting of the Central Commission for Civil-Military Integration and Development on September 22, 2017 and said in his speech, “promoting civil-military integration and development is a systems engineering of which systems science, thinking and methods should be used.”

The successful 19th National Congress of the Communist Party of China symbolizes the entry of Chinese socialist modernization construction into a new era, which also brings new opportunities for the development and application of systems science and systems engineering. We shall greatly promote and give play to the revolutionary effect of systems science and systems engineering and make new contributions to the development and progress of the new era.