Systems Science

Introduction

In the Systems Overview Knowledge Area we defined system as a general idea which can be applied to help understand complex real world situations, and System Science (glossary) as a collective term for a number of scientific disciplines which have applied this idea to different domains in different ways.

Principles and Concepts

general system theory (von Bertalanffy, 1968) considers the similarities between systems from different domain as a set of common systems principles and concepts. GST allows us to make comparisons between system based on different technologies; judge the goodness or completeness of a system and develop domain independent systems approaches which can form the basis of disciplines such as Systems Engineering.

• A principle is a rule of conduct or behavior. To take this further we can say that a principle is a “basic generalization that is accepted as true and that can be used as a basis for reasoning or conduct.” [WordWeb.com] A principle can also be thought of as a “basic truth or law or assumption.” [ibid.]

• A concept is an abstraction; a general idea inferred or derived from specific instances. For example, we look at our pet dog and we can infer that there are other dogs of that “type.” Hence, from this observation (or perhaps a set of observations) we develop a concept of a dog in our mind. Concepts are bearers of meaning, as opposed to agents of meaning and can only be thought about, or designated, by means of a name.

Principles depend on concepts in order to state this “truth.” Hence, principles and concepts go hand in hand; principles cannot exist without concepts and concepts are not very useful without principles to help us understand the proper way to act (Lawson and Martin 2008).

GST tends to concentrate on the principles and philosophy behind this idea. “Despite the importance of system concepts … we do not yet have a unified or integrated set (i.e. a system) of such concepts” (Ackoff, 1971).

While many researchers and practitioners have created GST concepts, these tend to be a stepping stone to theories and approaches. This situation is made worse by the variety of domains and disciplines in which systems research is conducted and reported. Ackoff proposes a System of System Concepts to bring together the wide variety of concepts which have been proposed. His 30 distinct concepts are grouped under four headings, or principles, “How Systems are formed”; “How System Change”; “How Systems Behave” and “How Systems Adapt and Learn”.

Lawson describes a System of System Concepts (Lawson 2010) where systems are categorized according to Fundamental concepts, Types, Topologies, Focus, Complexity and Roles. Hitchins (Hitchins, 2009) defines a similar set of principles which also consider some of the issues of hierarchy and complexity of particular relevance to a system approach.

In this Knowledge area we will identify a set of System Principles, against which the important System Concepts taken from a range of System Science (glossary) sources have been described. These concepts form a set of axioms, assumptions, and premises which can be applied to both the understanding of natural systems and social systems ; and to the understanding and/or intervention in engineered systems or sociotechnical systems .

The System Principles are summarized here, and used to organize the concepts in the Overview of System Concepts:

1. Wholeness: all systems are formed from groups of related elements into a whole with an observable shared identity in an environment.
2. Behavior: all systems exhibit behaviors resulting from the interaction between elements.
3. Survival Behavior: all systems have one or more stable state, and will act to sustain those states against environmental pressures of disturbances.
4. Goal Seeking Behavior: some systems will exhibit more complex combinations of behavior to create the functions needed to complete specific goals or broader objectives.
5. Control: all systems have regulation and control mechanism to guide their behaviors.
6. Effectiveness: some systems are able to assess their effectiveness against a desired objective and to adaption and learn to sustain and improve that effectiveness
7. Hierarchy: all systems form hierarchical structures, additional behaviors will emerge within the hierarchy due to interactions between system elements.
8. Complexity: at some levels of a hierarchy systems are sufficiently complex that they can only be understood, used or changed through a Systems Approach.

One of the purposes of this part of the SEBoK is to identify those aspects of systems science which apply to Systems Engineering, through the application a systems approach within a defined system context . The topics of Hierarchy, Complexity and Emergence help us to identify which system need a Systems Approach, and how to tailor that approach to suit the kinds of problem and appropriate solutions.

Topics

The topics contained within this knowledge area include:

• Overview of System Concepts
• System Context
• Complexity
• Emergence

References

Citations

von Bertalanffy, L. 1968. General system theory: Foundations, development, applications. Revised ed. New York, NY: Braziller.

Ackoff, R.L. 1971. Towards a System of Systems Concepts, Management Science, Vol.17 No. 11, USA.

Hitchins, Derek. 2009. What are the General Principles Applicable to Systems? Insight, 59-63.

Lawson, H., and Martin, J. N. 2008. On the Use of Concepts and Principles for Improving Systems Engineering Practice, INCOSE, Proceedings of the INCOSE International Conference, Utrecht.

Lawson, H. 2010. A Journey Through the Systems Landscape. London: College Publications, Kings College.

Primary References

Checkland, P. 1999. Systems Thinking, Systems Practice, New York, John Wiley & Sons.

Hitchins, D. 2007. Systems Engineering: A 21st Century Systems Methodology. Hoboken, NJ, USA: John Wiley & Sons.

Hitchins, Derek. 2009. What are the General Principles Applicable to Systems? Insight, 59-63.

Page, S. E. 2009. Understanding Complexity. The Great Courses. Chantilly, VA, USA: The Teaching Company.

Sheard, S. A. & Mostashari, A. 2008. Principles of Complex Systems for Systems Engineering. Systems Engineering, 12, 295-311.

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--Radcock 19:19, 15 August 2011 (UTC)