Foundations of Systems Engineering

SEBOK Part 2 is a guide to knowledge associated with system , particularly knowledge relevant to systems engineering .

To download a PDF of Part 2, please click here.

Knowledge Areas in Part 2: Systems

Part 2: Systems, contains the following knowledge areas:

Introduction

How can systems engineers benefit from understanding the broader context for their discipline, in terms of theories and practices of systems science and other fields of systems practice?

Most systems engineers are practitioners, applying processes and methods that have been developed and evolved over decades. SE is a pragmatic approach, inherently interdisciplinary, yet specialized. Systems engineers usually work within a specific domain, using processes and methods that are tailored to their domain’s unique problems, constraints, risks and opportunities, and that capture domain experts’ knowledge of the best order to tackle issues as we approach a problem in the particular domain.

Specific domains in which systems approaches are used and adapted include

Technology products – integrating multiple engineering disciplines
Information-rich systems – command & control, air traffic management etc
Platforms – aircraft, civil airliners, cars, trains, etc -
Organisational and enterprise systems, which may be focused on delivering service or capability
Civil engineering/infrastructure systems

The specific skill-sets for each domain and system scale may be quite different. However there are certain underlying unifying principles based on systems science and systems thinking that will improve the effectiveness of the systems approach in any domain, and in particular, improve our ability to integrate complex systems that span traditional domain boundaries - increasingly needed to solve today’s complex system challenges. But as these different communities come together, they find that assumptions underpinning their world-views are not shared.

To bridge between different domains and communities of practice, we need a well-grounded definition of the “intellectual foundations of systems engineering”, and a common language to describe the relevant concepts and paradigms. We need to look beyond systems engineering to achieve this. An integrated systems approach for solving complex problems needs to combine elements of systems science, systems thinking and systems engineering, and needs to provide a framework and language that allow different communities to work together for a common purpose.

The Systems Praxis Framework

The term “systems praxis” refers to the whole intellectual and practical endeavour for creating holistic solutions to today’s complex system challenges. Systems praxis requires many communities to work together. To work together we must first communicate; and to communicate, we must first connect. The Framework for unifying systems praxis was developed by members of INCOSE and ISSS (IFSR 2012) as the first step towards a “common language for systems praxis”. The diagram below shows the flows and interconnections among elements of a “knowledge ecosystem” of systems theory and practice.

In this framework, the following elements are connected: Systems thinking is the core integrative element of the framework. It binds the foundations, theories and representations of systems science together with the hard, soft and pragmatic approaches of systems practice. Praxis “puts theories into action”. In systems praxis, as in any practical discipline underpinned by science, there is constant interplay between theories and practice, with theory informing practice, and outcomes from practice informing theory. Interdisciplinary systems science has a very wide scope and is grouped into three broad areas: • Foundations, which help us to organize knowledge, learning and discovery, and include: meta-theories of methodologies; ontology; epistemology; axiology; praxiology (theory of effective action); teleology, semiotics & semiosis; category theory; etc. • Theories about systems, abstracted from domains and specialisms so as to be universally applicable: general systems theory; systems pathology; complexity; anticipatory systems; cybernetics; autopoiesis; living systems; science of generic design; organization theory; etc. • Representations, that we can use to describe, analyse and make predictions about systems and their wider context – such as: models; dynamics; networks; cellular automata; life cycles; queuing theory; graph theory; rich pictures; narrative; games and dramas; agent based simulations; etc. Systems approaches to practice aim to act on the real world to produce desired outcomes without adverse unintended consequences; so practice needs to draw on the wide range of knowledge appropriate to the system of interest and its wider context. No one branch of systems science provides a satisfactory explanation for all aspects of a typical system “problematique”; a pragmatic approach judiciously selects an appropriate set of tools and patterns that will give sufficient and appropriate insights to manage the issue at hand. Systems approaches to practice are grouped into three broad areas. • Hard approaches are suited to solving well-defined problems using analytical methods and quantitative techniques. Strongly influenced by “machine” metaphors, they focus on technical systems, objective complexity, and optimization to achieve desired combinations of emergent properties. They are based on “realist” and “functionalist” foundations and worldview. • Soft approaches: are suited to problem structuring and open inquiry within a learning system metaphor; focus on communication, subjective complexity, interpretations and roles; and draw on subjective and “humanist” philosophies with constructivist and interpretivist foundations. • Pragmatic approaches apply multiple methodologies drawn from different foundations as appropriate to the situation. Heuristics, boundary techniques, model unfolding, etc, enable a deep understanding of assumptions, contexts, and complexity due to different stakeholders’ values and valuations. An appropriate mix of hard, soft and custom methods draws on both systems and domain-specific traditions. Systems may be viewed as networks, ecosystems, machines, societies, discourses, etc. The set of “clouds” that collectively represents systems praxis is part of a wider ecosystem of knowledge, learning and action. Successful integration with this wider ecosystem is key to success with real world systems. Systems science is augmented by “hard” scientific disciplines such as physics and neuroscience, and by formal disciplines such as mathematics, logic and computation; it is both enhanced by, and used in, humanistic disciplines such as psychology, culture, and rhetoric, and pragmatic disciplines, such as accounting, design, and law. Systems practice depends on measured data and specified metrics relevant to the problem situation and domain, on solicitation of local values and knowledge, and on pragmatic integration of legacy practices and discipline knowledge.

So in summary: Integrative Systems Science allows us to identify, explore and understand patterns of complexity through contributions from the foundations, theories and representations of systems science and other disciplines relevant to the “problematique”. Systems approaches to practice address complex problems and opportunities using methods, tools, frameworks, patterns, etc, drawn from the knowledge of integrative systems science, while observation of the results of systems practice enhances the body of theory. And systems thinking binds the two together through appreciative and reflective practice using “system paradigms”, concepts, principles, patterns etc.

Scope of Part 2

Part 2 of the SEBoK contains a guide to knowledge about systems, which is relevant to a full understanding of SE. It does not try to capture all of the available system knowledge; rather, it provides an overview and guide too many aspects of systems theory and practice relevant to the SEBoK.

The following diagram summarizes the way in which the knowledge in SEBoK Part 2 is organized.

Figure 2. The relationships between key systems ideas and Systems Engineering. (SEBoK Original)

The diagram is divided into five sections, each describing how we have treated systems knowledge in the SEBoK.

The Systems Fundamentals Knowledge Area considers the question “What is a Systems? This section explores the wide range of system definitions and focuses on Open Systems, generic System Types, Complexity and Emergence. All of these ideas are particularly relevant to engineered system and to the groupings of such systems associated with the Systems Approach described in detail in KA 5 (i.e. product system , service system , enterprise system and system of systems (sos) Capability).
The Systems Science Knowledge Area provides an overview of the most influential movements in systems science. This section explores the chronological development of systems knowledge and discusses the underlying theories behind some of the approaches taken in applying it to real problems. This is useful background knowledge of general interest to systems engineers, in particular those involved in development of SE standards and descriptions.
The Systems Thinking Knowledge Area describes key Concepts, Principles and Patterns shared across systems research and practice and organizes them as a system of related ideas. Understanding this way of thinking should be a key competence for anyone undertaking systems research or practicing SE.
The Representing Systems with Models Knowledge Area considers the key role that abstract models play in both the development of system theories and the application of Systems Approaches.
The Systems Approach Applied to Engineered Systems Knowledge Area defines a structured problem or opportunity discovery, as well as exploration and resolution approaches that can be applied to all engineered systems , which is based on systems thinking and utilizes appropriate elements of system approaches and representations. This KA provides principles that map directly to SE practice.

It should be noted that, while the knowledge presented in this part of the SEBoK has been organized into these areas to facilitate understanding, the intention is to present a rounded picture of research and practice based on system knowledge. These knowledge areas are tightly coupled and should be seen together as a system of ideas for connecting understanding, research, and practice, based on system knowledge which applies to all types of domains and underpins a wide range of scientific, management, and engineering disciplines.

Systems Thinking is a fundamental paradigm describing a way of looking at the world. People competent in Systems Thinking are essential to the success of both research and practice. In particular, individuals who have an awareness and/or active involvements in both research and practice are needed to help integrated these closely related activities. This part of the SEBoK aims to help encourage such closer linked between the two systems domains as discussed in the Systems Praxis Framework.

Systems Thinking

The origins of systems thinking began in attempts to better understand complex situations in biology, organizations, control, etc. From these attempts come a set of fundamental concepts defining the idea of an open system and associated principles such as holism, emergence, etc. which have become the foundations of system thinking.

Figure 3. Systems Thinking and Systems Science. (SEBok Original)

Over time, systems thinking has been extended and refined by the creation of a set of abstract system models and a system of systems-concepts, which apply to all systems, independent of their domain.

System science is a community of research and practice which is based on systems thinking, and which adds to and evolves the systems thinking body of knowledge.

Systems Thinking stands alone as a way of thinking which “Systems People” can use to gain a fuller understanding of any situation and through this, guide a wide range of human activity.

Checkland (1999) discusses the use of systems thinking as a way to both understand and intervene in a problem situation. Lawson (2010) defines three related contexts in which systems thinking can be used:

to better understand a current real world situation by defining an abstract Situation System;
to describe the Respondent System that might be used to understand, use, manage, sustain or change the situation system;
to understand how one or more system assets needs be acquired, modified, or created to achieve the purpose of the respondent system.

Systems Science

systems science is an interdisciplinary field of science that studies the nature of complex systems in nature, society, and science. It aims to develop interdisciplinary foundations, which are applicable in a variety of areas, such as engineering, biology, medicine and social sciences. This systems science is practiced by a community of system researchers who perform research based on systems thinking.

File:Fig 3 Systems Science and Systems Thinking RA.jpg

Figure 4. Systems Science and Systems Thinking. (SEBoK Original)

Many systems science practitioners also develop system methodologies that provide a framework of concepts and principles for tackling specific aspects of system problems.

These methodologies are grouped around a set of paradigms which define particular world views or ways of thinking about systems, e.g., hard systems, soft systems, system dynamics, etc.

Another output of system science is the emergence of a theory of problem solving (also referred to as a theory of engineering, design, intervention, etc.). Some of this theory is published, and some is embedded in the methodologies.

The work of system science expands the shared understanding of systems and is used to evolve the body of knowledge of systems thinking, both in expanding the system-concepts, and in creating new models or modeling notations.

Systems science should be conducted by researchers who are themselves competent in systems thinking. As discussed above, this will include understanding the situation system under study, creating a research resolution system, and understanding any needed research system assets.

Systems Approach

SE lifecycle and process definitions, standards, and guides are underpinned by aspects of systems science and make use of system methodologies, but this is often not done in a rigorous or consistent way. Those conducting SE are often simply following process definitions and are not aware of the fundamentals and relevance of systems thinking.

File:Fig 4 Systems Engineering and the Systems Approach RA.jpg

Figure 5. Systems Engineering and the Systems Approach. (SEBoK Original)

A Systems Approach can be defined, synthesizing elements of Systems Science to create:

A framework of activities that can be applied to complex situations requiring engineered system based solutions.
System principles within each activity that relate back to the systems thinking models and concepts.

The activities and principles of the systems approach can be mapped onto the processes of SE to increase the system science foundations of SE.

This mapping will provide guidance on which system-concepts should be considered when applying a process and which system models can be used to support process activities.

SE should be practiced by those who are themselves competent in systems thinking. As discussed above, this will include understanding the problem or opportunity situation of a system, creation of a respondent system, and the understanding of life cycle management any system products or services assets.

References

Works Cited

Checkland, P B. 1999. Systems Thinking, Systems Practice. Chichester, England, UK: John Wiley and Sons.

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

Primary References

Bertalanffy, L., von. 1968. General System Theory: Foundations, Development, Applications, rev. ed. New York, NY, USA: Braziller.

Checkland, P. B. 1999. Systems Thinking, Systems Practice. Chichester, UK: John Wiley & Sons.

Additional References

MITRE Corporation. 2011. Systems Engineering Guide: Comprehensive Viewpoint. Accessed 2/28/2012 at http://www.mitre.org/work/systems_engineering/guide/enterprise_engineering/comprehensive_viewpoint/

MITRE Corporation. 2011. Systems Engineering Guide: Systems Thinking. Accessed 2/28/2012 at http://www.mitre.org/work/systems_engineering/guide/enterprise_engineering/comprehensive_viewpoint/systems_thinking.html

Senge, P. M. 1990. The Fifth Discipline: The Art & Practice of the Learning Organization. New York, NY: Doubleday Business.

< Previous Article | Parent Article | Next Article >

SEBoK v. 1.9.1 released 30 September 2018

SEBoK Discussion

Please provide your comments and feedback on the SEBoK below. You will need to log in to DISQUS using an existing account (e.g. Yahoo, Google, Facebook, Twitter, etc.) or create a DISQUS account. Simply type your comment in the text field below and DISQUS will guide you through the login or registration steps. Feedback will be archived and used for future updates to the SEBoK. If you provided a comment that is no longer listed, that comment has been adjudicated. You can view adjudication for comments submitted prior to SEBoK v. 1.0 at SEBoK Review and Adjudication. Later comments are addressed and changes are summarized in the Letter from the Editor and Acknowledgements and Release History.

If you would like to provide edits on this article, recommend new content, or make comments on the SEBoK as a whole, please see the SEBoK Sandbox.

blog comments powered by Disqus