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There are many definitions of complexity, therefore many natural, artificial and abstract objects or networks can be considered to be complex systems, and their study (complexity science) is highly interdisciplinary. Examples of complex systems include ant-hills, ants themselves, human economies, climate, nervous systems, cells and living things, including human beings, as well as modern energy or telecommunication infrastructures. Image File history File links Information_icon. ...
For the Computer Science term, see Computational complexity theory. ...
System (from Latin systēma, in turn from Greek sustēma) is a set of entities, real or abstract, comprising a whole where each component interacts with or is related to at least one other component. ...
Categories: Stub | Myrmecology ...
Subfamilies Aenictogitoninae Agroecomyrmecinae Amblyoponinae (incl. ...
Trinomial name Homo sapiens sapiens Linnaeus, 1758 Humans, or human beings, are bipedal primates belonging to the mammalian species Homo sapiens (Latin: wise man or knowing man) under the family Hominidae (the great apes). ...
The Human Nervous System The nervous system of an animal coordinates the activity of the muscles, monitors the organs, constructs and also stops input from the senses, and initiates actions. ...
Drawing of the structure of cork as it appeared under the microscope to Robert Hooke from Micrographia which is the origin of the word cell. Cells in culture, stained for keratin (red) and DNA (green). ...
Beyond the fact that these things are all networks of some kind, and that they are complex, it may appear that they have little in common, hence that the term "complex system" is vacuous. However, all complex systems are held to have behavioural and structural features in common, which at least to some degree unites them as phenomena. They are also united theoretically, because all these systems may, in principle, be modelled with varying degrees of success by a certain kind of mathematics. It is therefore possible to state clearly what it is that these systems are supposed to have in common with each other, in relatively formal terms. A mathematical model is an abstract model that uses mathematical language to describe the behaviour of a system. ...
Definition
Complex Systems is a new approach to science that studies how relationships between parts give rise to the collective behaviors of a system and how the system interacts and forms relationships with its environment. Part of a scientific laboratory at the University of Cologne. ...
System (from Latin systēma, in turn from Greek sustēma) is a set of entities, real or abstract, comprising a whole where each component interacts with or is related to at least one other component. ...
Applications of complex systems theory The study of complex systems is bringing new vitality to many areas of science where a more typical reductionist strategy has fallen short. Complex systems is therefore often used as a broad term encompassing a research approach to problems in many diverse disciplines including neurosciences, social sciences, meteorology, chemistry, physics, computer science, psychology, artificial life, evolutionary computation, economics, earthquake prediction, heart cell synchronisation, immune systems, reaction-diffusion systems, molecular biology, epilepsy and inquiries into the nature of living cells themselves. In these endeavors, scientists often seek simple non-linear coupling rules which lead to complex phenomena (rather than describe - see above), but this need not be the case. Human societies (and probably human brains) are complex systems in which neither the components nor the couplings are simple. Nevertheless, they exhibit many of the hallmarks of complex systems. Reductionism in philosophy describes a number of related, contentious theories that hold, very roughly, that the nature of complex things can always be reduced to (explained by) simpler or more fundamental things. ...
Neuroscience is a field of study which deals with the structure, function, development, genetics, biochemistry, physiology, pharmacology and pathology of the nervous system. ...
This article or section does not adequately cite its references or sources. ...
Satellite image of Hurricane Hugo with a polar low visible at the top of the image. ...
For other uses, see Chemistry (disambiguation). ...
Physics (Greek: (phúsis), nature and (phusiké), knowledge of nature) is the science concerned with the discovery and understanding of the fundamental laws which govern matter, energy, space, and time and explaining them using mathematics. ...
Computer science, or computing science, is the study of the theoretical foundations of information and computation and their implementation and application in computer systems. ...
Psychology is an academic and applied discipline involving the scientific study of mental processes, emotion, personality, behavior, and relationships. ...
Artificial Life, (commonly Alife or alife) is a field of study and art form that examines systems related to life, its processes and its evolution through simulations using computer models, robotics, and biochemistry [1] (called soft, hard, and wet approaches respectively[2]). Artificial life compliments traditional Biology by trying to...
In computer science evolutionary computation is a subfield of artificial intelligence (more particularly computational intelligence) involving combinatorial optimization problems. ...
This article or section does not cite its references or sources. ...
An earthquake is a phenomenon that results from the sudden release of stored energy in the Earths crust that creates seismic waves. ...
The heart and lungs, from an older edition of Grays Anatomy. ...
A request has been made on Wikipedia for this article to be deleted in accordance with the deletion policy. ...
Molecular biology is the study of biology at a molecular level. ...
Brains has several meanings. ...
Traditionally, engineering has striven to keep its systems linear, because that makes them simpler to build and to predict. However, many physical systems (for example lasers) are inherently "complex systems" in terms of the definition above, and engineering practice must now include elements of complex systems research. For alternative meanings see laser (disambiguation). ...
Information theory applies well to the complex adaptive systems, CAS, through the concepts of object oriented design. Complex adaptive systems, are a special case of complex systems. ...
Socio-cognitive complexity Socio-cognitive systems are complex from their nature. They include humans, organizations and are intelligence-based systems. The study of socio-cognitive complexity is the new domain in systemics and has to cope with a meta-complexity on higher levels in the hierarchy of abstract systems.[citation needed] Socio-cognitive may relate to systems, processes, functions, models, as well as can indicate the branch of science, engineering or technology, such as socio-cognitive research, socio-cognitive interactions. ...
Systems theory or general systems theory or systemics is an interdisciplinary field which studies systems as a whole. ...
Features of complex systems in nature
Relationships are non-linear In practical terms, this means a small perturbation may cause a large effect (see butterfly effect), a proportional effect, or even no effect at all. In linear systems, effect is always directly proportional to cause. See nonlinearity. Point attractors in 2D phase space. ...
In mathematics, nonlinear systems represent systems whose behavior is not expressible as a sum of the behaviors of its descriptors. ...
Relationships contain feedback loops Both negative (damping) and positive (amplifying) feedback are often found in complex systems. The effects of an element's behaviour are fed back to in such a way that the element itself is altered. It has been suggested that this article or section be merged with Feedback loop. ...
Complex systems are open Complex systems in nature are usually open systems — that is, they exist in a thermodynamic gradient and dissipate energy. In other words, complex systems are usually far from energetic equilibrium: but despite this flux, there may be pattern stability. See synergetics. An open system may refer to more than one thing: In the physical sciences, an open system (system theory) is a system that matter or energy can flow into and/or out of, in contrast to a closed system, which no energy or matter may enter or leave. ...
Thermodynamics (Greek: thermos = heat and dynamic = change) is the physics of energy, heat, work, entropy and the spontaneity of processes. ...
In thermodynamics, a thermodynamic system is said to be in thermodynamic equilibrium when it is in thermal equilibrium, mechanical equilibrium, and chemical equilibrium. ...
Inspired by the laser theory and founded by Hermann Haken, synergetics is an interdisciplinary science explaining the formation and self-organization of patterns and structures in open systems far from thermodynamic equilibrium. ...
Complex systems have a memory The history of a complex system may be important. Because complex systems are dynamical systems they change over time, and prior states may have an influence on present states. More formally, complex systems often exhibit hysteresis. In engineering and mathematics, a dynamical system is a deterministic process in which a functions value changes over time according to a rule that is defined in terms of the functions current value. ...
Hysteresis is a property of systems (usually physical systems) that do not instantly follow the forces applied to them, but react slowly, or do not return completely to their original state: that is, systems whose states depend on their immediate history. ...
Complex systems may be nested The components of a complex system may themselves be complex systems. For example, an economy is made up of organisations, which are made up of people, which are made up of cells - all of which are complex systems. This article needs to be cleaned up to conform to a higher standard of quality. ...
Drawing of the structure of cork as it appeared under the microscope to Robert Hooke from Micrographia which is the origin of the word cell. Cells in culture, stained for keratin (red) and DNA (green). ...
Boundaries are difficult to determine It can be difficult to determine the boundaries of a complex system. The decision is ultimately made by the observer.
Dynamic network of multiplicity As well as coupling rules, the dynamic network of a complex system is important. Small-world or scale-free networks which have many local interactions and a smaller number of inter-area connections are often employed. Natural complex systems often exhibit such topologies. In the human cortex for example, we see dense local connectivity and a few very long axon projections between regions inside the cortex and to other brain regions. Small World may refer to a number of things, including the following: Small World, a comic novel by the British author David Lodge. ...
Location of the cerebral cortex Slice of the cerebral cortex, ca. ...
An axon, or nerve fiber, is a long slender projection of a nerve cell, or neuron, which conducts electrical impulses away from the neurons cell body or soma. ...
May produce emergent phenomena Complex systems may exhibit behaviors that are emergent, which is to say that while the results may be deterministic, they may have properties that can only be studied at a higher level. For example, the termites in a mound have physiology, biochemistry and biological development that are at one level of analysis, but their social behavior and mound building is a property that emerges from the collection of termites and needs to be analysed at a different level. A termite cathedral mound produced by a termite colony: a classic example of emergence in nature. ...
Quotes - From Sync by Steven Strogatz: "Every decade or so, a grandiose theory comes along, bearing similar aspirations and often brandishing an ominous-sounding C-name. In the 1960s it was cybernetics. In the '70s it was catastrophe theory. Then came chaos theory in the '80s and complexity theory in the '90s."
Various informal descriptions of complex systems have been put forward, and these may give some insight into their properties. A special edition of Science about complex systems Science Vol. 284. No. 5411 (1999). highlighted several of these: Steven H. Strogatz is Professor of theoretical and applied mechanics at Cornell University. ...
Science is the journal of the American Association for the Advancement of Science (AAAS). ...
- A complex system is a highly structured system, which shows structure with variations (Goldenfeld and Kadanoff)
- A complex system is one whose evolution is very sensitive to initial conditions or to small perturbations, one in which the number of independent interacting components is large, or one in which there are multiple pathways by which the system can evolve (Whitesides and Ismagilov)
- A complex system is one that by design or function or both is difficult to understand and verify (Weng, Bhalla and Iyengar)
- A complex system is one in which there are multiple interactions between many different components (D. Rind)
- Complex systems are systems in process that constantly evolve and unfold over time (W. Brian Arthur).
See also Complex adaptive systems are special cases of complex systems. ...
Self-organization is a process in which the internal organization of a system, normally an open system, improves automatically without being guided or managed by an outside source. ...
For the Computer Science term, see Computational complexity theory. ...
A dynamical system is a concept in mathematics where a fixed rule describes the time dependence of a point in a geometrical space. ...
A termite cathedral mound produced by a termite colony: a classic example of emergence in nature. ...
There are very few or no other articles that link to this one. ...
In mathematics, nonlinear systems represent systems whose behavior is not expressible as a sum of the behaviors of its descriptors. ...
Systems theory is a transdisciplinary/multiperspectual scientific domain that studies structure and properties of systems in terms of relationships from which new properties of wholes emerge. ...
In computer science, a multi-agent system (MAS) is a system composed of several agents, collectively capable of reaching goals that are difficult to achieve by an individual agent or monolithic system. ...
Process architecture is the structural design of general process systems and applies to fields such as computers (software, hardware, networks, etc. ...
External links Institutes Directories Articles The Open Directory Project (ODP), also known as dmoz (from directory. ...
Mailing Lists, Discussion Groups and Forums The Proceedings of the National Academy of Sciences of the United States of America, usually referred to as PNAS, is the official journal of the United States National Academy of Sciences. ...
Murray Gell-Mann (born September 15, 1929 in Manhattan, New York City, USA) is an American physicist who received the 1969 Nobel Prize in physics for his work on the theory of elementary particles. ...
- Complexity Digest
- NECSI Discussion Forum
- NECSI Complex Systems Wiki
- FRIAM Mailing List
- Complex Adaptive Systems Group
Specialized Wikis and Sites about Complex Systems - Shalizi's Notebooks
- DCS-Wiki
- NECSI Wiki
Conferences - NICO's Annual Complexity Conference
- NECSI's Sixth International Conference on Complex Systems (ICCS2006)
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