Talk:Complex system/Archive 1

i shored up the definition

it was very leaky and i think it's better now. what say you all? --DhruvBansal

The revision you made seems like a definite improvement to me. -R. S. Shaw 21:01, 17 September 2006 (UTC)

A paragraph was moved here

The following paragraph was moved here because it seems to be very much POV:

We often hear of groups having "strong" or "weak" boundaries but without any clear sense of the meaning. I believe that it is possible to gain some clarity by considering connectivity. I hypothesise that an individual agent can only have a certain number of connections to other agents (with human agents this number will change according to the state of the individual and also the state of the environment). We can then think of the strength of a group's boundaries as the proportion of connections which are made within the group - the greater the proportion, the stronger the group boundaries. If all connections are made within the group it forms a closed system.

At the least, phrases containing I should be avoided. -- Kimiko 18:14, 24 Aug 2003 (UTC)

I just reverted an edit that added apostrophes to a few headings in the page. I'm guessing they were an attempt to add emphasis, but they broke the index. Since I was unable to guess the desired result, I couldn't repair the edit. Since it crippled the page, I just removed them. Jmeppley 22:55, 13 Aug 2004 (UTC)

Just wanted to say that I know nothing about systems theory or anything like that, and I found this article informative and well written. Kudos! Fishel 23:28, 1 Sep 2004 (UTC)

This Article Should be Rewritten

I'm sorry to find so much confusion about complexity here, as much as everywhere else. I would seriously recommend that authors, and others interested, familiarise themselves with the subject before trying to present it. As a beginning, I would suggest Klaus Mainzer "Thinking in Complexity".

There is not even a word on neural networks, agents or oscilators. The whole article simply describes (some) attributes without even trying to describe the phenomenon itself.

The division on Systems Theory and Complex Systems also indicates a lack of understanding. I'll be glad if my page ([1]) can help. I can also contribute, if you wish, but my English might need some editing.

Sincerely, Damir

Interesting

The universe seems to be arranged in hierarchies. There are various levels at which you can understand it. The level we are most familiar with is the level of everyday life. Going down we run into the levels of organs, cells, molecular biology, chemistry. Each level has its own laws which work in certain "special cases" with all violations at the "extremes". Complex Adaptive Swarms exhibit similar layered behavior also, at each layer the swarm is made of smaller complex adaptive systems. This layered behavior doesn't appear in swarms made of simple systems. This all seems to imply that either there is no bottom to the layers of the universe(and no TOE) or, the bottom layer is made of smart, adaptive particles.--SurrealWarrior 18:09, 12 July 2005 (UTC)

Relationship with Socio-technical systems?

This seems to have some overlap with socio-technical systems, so I think some degree of integration or at least simple linking should be done, but I'll put it here for consideration before doing anything on it. Spalding 21:33, July 16, 2005 (UTC)

Rigorous definition??

There seems to be a completely lack a rigorous mathematical definition of what complex systems are, but then I suspect that is part of the problem with complex systems in that is can be tricky pinning down *exactly* what it is. Mathmo 08:34, 14 August 2005 (UTC)

I have re-written this

As the editors above note, this article was in a rather bad state. "Complexity" is a buzzword at the moment, and unfortunately many are confused over what is entailed. As a PhD student in complex systems, I thought I'd straighten it out as best I could - including a reasonably formal (but with links to the articles you would need to make it genuinely formal) definition that I find satisfying. The emphasis in what I have written is very much on non-linearity, because that is what it is all about really.

I would really very much prefer discussion on this page rather than a petulant reversion of my edits - I spent a good hour going through this. Duracell 21:03, 13 September 2005 (UTC) (http://www.ccs.fau.edu)

removed sentence

I just removed a sentence "complex systems are heavily inertial" inertia is a physical property of objects with mass. It is inappropriate to use in terms of a complex system, whether mathematical or real. In any case, the sentence is not true. Many complex systems are marked by rapid changes because although there are a large number of connections, there is also high connectivity, e.g. in the brain any neuron is only a hop skip and jump away from any other. So this sentence is rubbish.

The paragraph on network topology was removed. It had some issues and may have been misplaced, but it has some useful content. I put it back for now... Jmeppley 17:17, 18 October 2005 (UTC)

Complex Systems & Complexity

I have left comments under the "Complexity" heading after seeing that the article seemed lacking. Then I found this one (Complex Systems). If there are links between these two articles it doesn't seem very obvious. I don't understand why there are two different articles to begin with. Isn't Complexity just another name for the scientific field which studies complex systems?

It seems to me that there should just be one article called "Complex Systems Theory". Then "Complexity", "Complex Systems", and "Systems Theory" should ALL just redirect to that article.

If we're not going to do that, then at least there should be really obvious links between these two articles. Thanks, DT Strain - October 28, 2005

Proposed Merge

The Systems theory article comments, " In recent times complex systems has increasingly been used as a synonym". It is a smaller article, containing useful background and broadly covering the same subject matter, but not as extensive a treatment as Complex systems.

Article merge proposed. Comments? FT2 20:20, 30 October 2005 (UTC)

Not only should these two be merged, but we have another article out there lingering which is even closer titled: Complexity. It too should be merged.

I haven't looked at the complexity page, but I agree that it is conceptually similar or identical and the two should be merged. Systems theory, on the other hand, is a very old discipline, and I do not think that many of its practitioners would appreciate being forcibly thrown on the complex systems bandwagon by merging their page with this one, so I tihnk best leave that. Duracell 00:29, 1 November 2005 (UTC)

-- DT Strain, 31 October 2005

You're probably right Duracell. I don't really know as much about traditional Systems Theory to say (although it seems likely a separate article is called for), but I have a fairly decend layman's understanding of Complex Systems theory, and it's my understanding that "Complexity" is just a nickname for it. In my opinion, this article is the better and more complete of the two (although I'd make a few changes and additions), but I'd prefer to see "Complexity" merged into this one (Complex Systems) before making any other recommendations. -- DT Strain, 1 November 2005.

I don't think that the two pages should be merged. The term 'Systems Theory' has been the general indication for the interdisciplinairy field of study of systems since the 1950's. The term should for this reason be preserved as part of the history of science. In my opinion in the 1990's it happened that scientists started to use other terms to indicate the interdisciplinairy field of study as the term 'complex systems' and other terms. I think that it is important to keep dividing this development instead of wanting to make it to 'one single thing', with it has never been. - Mdd 17.09 15 November 2005 (CEST)

I have noticed that the cybernetics article needs attention from a specialist, and I wonder if there is not one underlaying problem here. This problem is to give a good represenation in the wikipedia of the whole field of system studies, cybernetics, complexity etcetera? I think that the current structure isn't optimal --- Mdd 12.05 23 November 2005 (CEST)

I have initiated that The merge is off because of the following reasons:

• From a historical perspective systems theory and complex systems theory are not the same.
• All ready in the 1950s all kinds of terms where cointed by the pioneers of the Systems movement like General systems theory , Systems theory , General empirical theory , Behavioral science , General systems , Systems research , General Systems Research and Systems science.
• Eversince more other terms came up and around 1970 people like Madridakis, Klir and Ackoff spoke about the terminological jungle charaterizing general systems theory.
• Other developments happened which are not quiet clear to me, like a kinds of terminological interferrances between system theory and General System theory (Bertalanffy) versus systems theory and General Systems Theory (the others) in the 1950s, between cybernetics and systems theory in the 1960s, between systems dynamics and systems theory in the 1970s, between systems science and systems theory in the 1980s and complex systems theory and systems theory in the 1990s. All this time the term systems theory seemed to restore itselve to a central general term in the movement.
• Another point is the institutionalization of the term system theory in all kinds of databases and information systems.

In historical perspective it's clear that systems theory and complex systems are not the same subject matter. --- Mdd 15.05 25 November 2005 (CEST)

Where would Linear system theory fit?

Where would Linear system theory, LTI system theory fit? I think someone needs to verify that it indeed is "used as a synonym" not just "used as a shortform for complex systems theory" :P--Ben 05:54, 19 November 2005 (UTC)

Well you can imagine what my opinion on that would be. Linear systems are not "complex systems" if that term is to be salvagable. "Complex system" is a bit of a problematic term since it is used/misused so frequently that it is in danger of becoming meaningless or vacuous. However, it does seem to me that the main thing that has thrust this area into the limelight is the devolopment of non-linear dynamical systems theory and the computers to explore it. That is ultimately what produces the really interesting behaviours, be it homeostasis, multistability or whatever. So, I would argue that linear systems theory should be kept distinct, and really thought of as seperate from complex systems. But I'm sure not everyone would agree. Duracell 20:37, 19 November 2005 (UTC)

NOTE: actually, re: linear systems: something that is of technical interesest is linearization, where one makes a linear approximation of a non-linear function at an equilibrium point (i.e. point attractor/repellor) to determine stability. In that sense, linear systems theory and non-linear systems theory are conjunctive. So a link should maybe be added - should this article be a general "overview" article, or should it go into technical details like this? Duracell 20:50, 19 November 2005 (UTC)

The question I have is "does the field of systemics encompass linear systems?" If no, then I find that very strange because to me "Systemics" and "Systems theory" suggests that it indeed does (and if yes, then obviously they shouldn't be merged.) Not all systems are non-linear, and thus not all systems are complex (which are defined as non-linear). "Complex systems" to me suggests a "a study of a type of system" rather than "a study of systems." --Ben 22:03, 21 November 2005 (UTC)

Yes, I think that is exactly right Duracell 18:32, 28 November 2005 (UTC)