Latin"systēma", in turn from Greek "polytonic|σύστημα" systēma) is a set of interacting or interdependent entities, real or abstract, forming an integrated whole.
The concept of an "integrated whole" can also be stated in terms of a system embodying a set of relationships which are differentiated from relationships of the set to other elements, and from relationships between an element of the set and elements not a part of the relational regime.
The scientific research field which is engaged in the transdisciplinary study of universal system-based properties of the world is general
systems theory, systems scienceand recently systemics. They investigate the abstract properties of the matter and mind, their organization, searching concepts and principles which are independent of the specific domain, independent of their substance, type, or spatial or temporal scales of existence.
The term "system" has multiple meanings  :
#A collection of organized things; as, a solar system.
#A way of organizing or planning.
#A whole composed of relationships among the members.
Most systems share the same common characteristics. These common characteristics include the following: [ [Michael Pidwirny] , "Definitions of Systems and Models", 1999-2007.]
# Systems have a structure that is defined by its parts and processes.
# Systems are generalizations of reality.
# Systems tend to function in the same way. This involves the inputs and outputs of material (energy and/or matter) that is then processed causing it to change in some way.
# The various parts of a system have functional as well as structural relationships between each other. The characteristics of systems have been studied in
general systems theory.
The term "System" has a long history which can be traced back to the
In the 19th century the first to develop the concept of a "system" in the
natural scienceswas the French physicist Sadi Carnot who studied thermodynamics. In 1824he studied what he called the "working substance" (system), i.e. typically a body of water vapor, in steam engines, in regards to the system's ability to do work when heat is applied to it. The working substance could be put in contact with either a heat reservoir (a boiler), a cold reservoir (a stream of cold water), or a piston (to which the working body could do work by pushing on it). In 1850, the German physicist Rudolf Clausiusgeneralized this picture to include the concept of the surroundings and began to use the term "working body" when referring to the system.
1980s the term complex adaptive systemwas coined at the interdisciplinary Santa Fe Instituteby John H. Holland, Murray Gell-Mannand others.
;Environment and boundaries:
Systems theoryviews the world as a complex system of interconnected parts. We scope a system by defining its "boundary"; this means choosing which entities are inside the system and which are outside - part of the "environment". We then make simplified representations ( models) of the system in order to understand it and to predict or impact its future behavior. These models may define the structureand/or the behaviourof the system.
;Natural and man-made systems:There are natural and man-made (designed) systems. Natural systems may not have an apparent objective but their outputs can be interpreted as purposes. Man-made systems are made with purposes that are achieved by the delivery of outputs. Their parts must be related; they must be “designed to work as a coherent entity” - else they would be two or more distinct systems
;Open system:An open system usually interacts with some entities in their environment. A
closed systemis isolated from its environment.
;Process and transformation process:A system can also be viewed as a bounded transformation process, that is, a process or collection of processes that transforms inputs into outputs. Inputs are consumed; outputs are produced. The concept of input and output here is very broad. E.g. An output of a passenger ship is the movement of people from departure to destination.
;Subsystem:A "subsystem" is a set of elements, which is a system itself, and a
partof a larger system.
Types of systems
Evidently, there are many types of systems that can be analyzed both
quantitatively and qualitatively. For example, with an analysis of urban systems dynamics, [A.W. Steiss] [ Steiss 1967, p.8-18.] defines five intersecting systems, including the physical subsystem and behavioral system. For sociological models influenced by systems theory, where Kenneth D. Bailey[ Bailey, 1994. ] defines systems in terms of conceptual, concreteand abstract systems; either isolated, closed, or open, Walter F. Buckley[ Buckley, 1967.] defines social systems in sociology in terms of mechanical, organic, and processmodels. Bela H. Banathy[Banathy, 1997.] cautions that with any inquiry into a system that understanding the type of system is crucial and defines Natural and Designed systems.
In offering these more global definitions, the author maintains that it is important not to confuse one for the other. The theorist explains that natural systems include sub-atomic systems, living systems, the
solar system, the galacticsystem and the Universe. Designed systems are our creations, our physical structures, hybrid systems which include natural and designed systems, and our conceptual knowledge. The human element of organization and activities are emphazized with their relevant abstract systems and representations. A key consideration in making distinctions among various types of systems is to determine how much freedom the system has to select purpose, goals, methods, tools, etc. and how widely is the freedom to select distributed (or concentrated) in the system. George J. Klir[Klir 1969, pp. 69-72] maintains that no "classification is complete and perfect for all purposes," and defines systems in terms of abstract, real, and conceptual physical systems, boundedand unbounded systems, discrete to continuous, pulse to hybrid systems, et cetera. The interaction between systems and their environments are categorized in terms of absolutely closed systems, relatively closed, and open systems. The case of an absolutely closed system is a rare, special case. Important distinctions have also been made between hard and soft systems. [ Checkland 1997; Flood 1999.] Hard systems are associated with areas such as systems engineering, operations research and quantitative systems analysis. Soft systems are commonly associated with concepts developed by Peter Checklandthrough Soft Systems Methodology(SSM) involving methods such as action researchand emphasizing participatory designs. Where hard systems might be identified as more "scientific," the distinction between them is actually often hard to define.
A cultural system may be defined as the interaction of different elements of
culture. While a cultural system is quite different from a social system, sometimes both systems together are referred to as the sociocultural system. A major concern in the social sciences is the problem of order. One way that social order has been theorized is according to the degree of integration of cultural and social factors.
An economic system is a mechanism (
social institution) which deals with the production, distribution and consumption of goods and services in a particular society. The economic system is composed of people, institutionsand their relationships to resources, such as the convention of property. It addresses the problems of economics, like the allocation and scarcity of resources.
Application of the system concept
Generally systems modeling is a basic principle in engineering and in social sciences. The system is the representation of the entities under concern. Hence inclusion to or exclusion from system context is dependent of the intention of the modeler.
No model of a system will include all features of the real system of concern, and no model of a system must include all entities belonging to a real system of concern.
ystems in information and computer science
computer scienceand information science, system could also be a method or an algorithm. Again, an example will illustrate: There are systems of counting, as with Roman numerals, and various systems for filing papers, or catalogues, and various library systems, of which the Dewey Decimal Systemis an example. This still fits with the definition of components which are connected together (in this case in order to facilitate the flow of information).
System can also be used referring to a framework, be it software or hardware, designed to allow software programs to run, see platform.
ystems in engineering
In engineering, the concept of a "system" is usually well defined. It is used in numerous different concrete contexts, and it is the subject of the basic engineering activities, such as: planning, design, implementation, building, and maintaining.
Systems engineeringis also a generalized theoretical branch of the different engineering approaches and paradigms.
ystems in social and cognitive sciences and management research
Social and cognitive sciences recognize systems in human person models and in human societies. They include human brain functions and human mental processes as well as normative ethics systems and social/cultural behavioral patterns.
management science, operations researchand organizational development(OD), human organizations are viewed as systems (conceptual systems) of interacting components such as subsystems or system aggregates, which are carriers of numerous complex processes and organizational structures. Organizational development theorist Peter Sengedeveloped the notion of organizations as systems in his book "The Fifth Discipline". Systems thinkingis a styleof thinking/ reasoningand problem solving. It starts from the recognition of system properties in a given problem. It can be a leadership competency. Some people can "think globally while acting locally". Such people consider the potential consequences of their decisions on other parts of larger systems. This is also a basis of systemic coachingin psychology.
Organizational theorists such as
Margaret Wheatleyhave also described the workings of organizational systems in new metaphoric contexts, such as quantum physics, chaos theory, and the self-organization of systems.
In modern systemic
socio-cognitiveengineering the concept "system" is generalized to so-called intelligence-based systems. The Top-down Object-based Goal-oriented Approach (TOGA meta-theory) integrates formally the concepts of "system", " process", "function" and " goal" in frame of one congruent conceptualization meta-system. Among others, this paradigm enables the computational analysis of heterogeneous human-organization-technology aggregates and recognition of their pathological properties such as organization vulnerability, crisisand changes [ Adam Maria Gadomski, "Modeling of socio-cognitive vulnerability - TOGA meta-theory approach" [http://www.progettoreti.enea.it/cnip06/slides/Poster/Gadomski.pdf *] , International Workshop on Complex Network and Infrastructure Protection, [http://www.progettoreti.enea.it/cnip06/program.htm CNIP2006] , Rome ] .
;Examples of systems
* Systems in human anatomy
;Theories about systems
;Other related topics
Complexity and organization
Glossary of systems theory
* System of Systems
System of Systems Engineering
* Alexander Backlund (2000). "The definition of system". In: "Kybernetes" Vol. 29 nr. 4, pp. 444-451.
Kenneth D. Bailey(1994). "Sociology and the New Systems Theory: Toward a Theoretical Synthesis". New York: State of New York Press.
Bela H. Banathy(1997). [http://www.newciv.org/ISSS_Primer/asem04bb.html "A Taste of Systemics"] , ISSS The Primer Project.
Walter F. Buckley91967). " Sociology and Modern Systems Theory", New Jersey: Englewood Cliffs.
Peter Checkland(1997). "Systems Thinking, Systems Practice". Chichester: John Wiley & Sons, Ltd.
Robert L. Flood(1999). "Rethinking the Fifth Discipline: Learning within the unknowable". London: Routledge.
George J. Klir(1969). Approach to General Systems Theory, 1969.
* [http://www.physicalgeography.net/fundamentals/4b.html "Definitions of Systems and Models"] by Michael Pidwirny, 1999-2007.
* [http://www.muellerscience.com/SPEZIALITAETEN/System/System_Definitionen.htm "Definitionen von "System" (1572-2002)"] by Roland Müller, 2001-2007 (most in German).
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