Systems Engineering: Historic and Future Challenges
We can view the evolution of Systems Engineering (SE) in terms of challenges and responses. Humans have faced increasingly complex challenges and have had to think systematically and holistically in order to produce successful responses. From these responses, generalists have developed generic principles and practices for replicating success.
Historical Perspective
Some of the earliest relevant challenges were in organizing cities. Emerging cities relied on functions such as storing grain and emergency supplies, defending the stores and the city, supporting transportation and trade, afterlife preparations, providing a water supply, and accommodating palaces, citadels, and temples. The considerable holistic planning and organizational skills required to realize these functions were independently developed in the Middle East, Egypt, Asia, and Latin America, as described in Lewis Mumford’s The City in History (Mumford 1961).
Megacities, and mobile cities for military operations, such as those present in the Roman Empire, emerged next, bringing another wave of challenges and responses. These also spawned generalists and their ideological works, such as Vitruvius and his Ten Books on Architecture ( Vitruvius: Morgan transl. 1960). “Architecture” in Rome meant not just buildings, but also aqueducts, central heating, surveying, landscaping, and overall planning of cities.
The Industrial Revolution brought another wave of challenges and responses. In the nineteenth century, new holistic thinking and planning went into creating and sustaining transportation systems, including canal, railroad, and metropolitan transit. General treatises, such as The Economic Theory of the Location of Railroads (Wellington 1887), appeared in this period. The early twentieth century saw large-scale industrial enterprise engineering, such as the Ford automotive assembly plants, along with treatises like The Principles of Scientific Management (Taylor 1911).
The Second World War presented challenges around the complexities of real-time command and control of extremely large multinational land, sea, and air forces and their associated logistics and intelligence functions. The postwar period brought the Cold War and Russian space achievements. The U.S. and its allies responded to these challenges by investing heavily in researching and developing principles, methods, processes, and tools for military defense systems, complemented by initiatives addressing industrial and other governmental systems. Landmark results included the codification of operations research and SE in Introduction to Operations Research (Churchman et. al 1957), Warfield (1956), and Goode-Machol (1957) and the Rand Corporation approach as seen in Efficiency in Government Through Systems Analysis (McKean 1958). In theories of system behavior and SE, we see cybernetics (Weiner 1948), system dynamics (Forrester 1961), general systems theory (Bertalanffy 1968), and mathematical systems engineering theory (Wymore 1977).
Two further sources of challenge began to emerge in the 1960s, and accelerated in the 1970s through the 1990s: the growth of software functionality in systems, and, awareness of the criticality of the human element in complex systems.
While software was responsible for functionality in 8% of military aircraft in 1960, this number had risen to 80% in 2000 (Ferguson 2001). One response to this challenge is the appearance of Model-Based Systems Engineering (MBSE), which is better suited to managing complexity, including that of software, than traditional document-centric approaches (Friedenthal 2008).
Concerning awareness of the human element, the response was a reorientation from traditional SE toward “soft” SE approaches. Traditional hardware-oriented SE featured sequential processes, pre-specified requirements, functional-hierarchy architectures, mathematics-based solutions, and single-step system development. In “soft” SE we find emergent requirements, concurrent definition of requirements and solutions, combinations of layered service-oriented and functional-hierarchy architectures, heuristics-based solutions, and evolutionary system development. Good examples are societal systems (Warfield 1976), soft systems methodology (Checkland 1981) and systems architecting (Rechtin 1991; Rechtin-Maier 1997). As with Vitruvius, architecting is not confined to producing blueprints from requirements, but instead extends to concurrent work on operational concept, requirements, structure, and life cycle planning.
Evolution of Systems Engineering Challenges
From 1990 on, rapidly increasing scale, dynamism, and vulnerabilities in the systems being engineered have presented ever-greater challenges. The Internet offers efficient interoperability of net-centric systems of systems (SoS), but brings new sources of system vulnerability and obsolescence as new Internet services (clouds, social networks, search engines, geolocation services, recommendation services, and electrical grid and industrial control systems) proliferate and compete with each other.
Meanwhile, challenges come from several ways in which solution approaches have proliferated:
- While domain-specific model-based approaches offer significant benefits, reconciling many different domain assumptions to get domain-specific systems to interoperate is a challenge.
- The appearance of many competing object-oriented methods posed a problem that was addressed by the development of the Unified Modeling Language (UML) (Booch-Rumbaugh-Jacobson 1998) and the Systems Modeling Language (SysML) (Friedenthal 2008). However, the wave of UML and SysML tools that followed, along with a number of alternative requirements and architecture representations intended to compensate for shortcomings of UML and SysML, again create dilemmas around interoperability and choice.
- Among the areas that have seen a sometimes bewildering growth of alternatives are: enterprise architecture, lean and agile processes, iterative and evolutionary processes, and methods for simultaneously achieving high-effectiveness, high-assurance, resilient, adaptive, and life cycle affordable systems.
This trend towards diversity has increased awareness that there is no one-size-fits-all product or process approach that works best in all situations. In turn, determining which SE approaches work best in which situation, and how to sustain workable complex systems of systems containing different solution approaches, emerges as yet another challenge.
Similarly, assessing and integrating new technologies experiencing increasing rates of change presents further SE challenges. This is happening in such areas as biotechnology, nanotechnology, and combinations of physical and biological entities on the one hand, and mobile networking, social network technology, cooperative autonomous agent technology, massively parallel data processing, cloud computing and data mining technology on the other.
Ambitious projects to create smart services, smart hospitals, energy grids, and cities are underway. These promise improved system capabilities and quality of life, but carry risks of reliance on immature technologies or on combinations of technologies with incompatible objectives or assumptions. The advantages of creating network-centric systems of systems to “see first,” “understand first,” and “act first” are highly attractive in a globally competitive world, but carry challenges of managing complexes of hundreds of independently-evolving systems over which only partial control is possible. SE is increasingly needed but increasingly challenged in the quest to make future systems scalable, stable, adaptable, and humane.
To accommodate this complexity, the SEBoK presents alternative approaches along with current knowledge of where they work best. Being a wiki allows the SEBoK to evolve quickly while maintaining stability between versions.
References
Works Cited
Bertalanffy, L. von. 1968. General System Theory: Foundations, Development, Applications. New York, NY, USA: George Braziller.
Booch, G., J. Rumbaugh, and I. Jacobson. 1998. The Unified Modeling Language User Guide. Reading, MA, USA: Addison Wesley.
Checkland, P. 1981. Systems Thinking, Systems Practice. Hoboken, NJ, USA: Wiley, 1981.
Churchman, C.W., R. Ackoff, and E. Arnoff. 1957. Introduction to Operations Research. New York, NY, USA: Wiley and Sons.
Ferguson, J. 2001. "Crouching Dragon, Hidden Software: Software in DoD Weapon Systems." IEEE Software, July/August, p. 105–107.
Forrester, J. 1961. Industrial Dynamics. Winnipeg, Manitoba, Canada: Pegasus Communications.
Friedenthal, S. 2008. A Practical Guide to SysML: The Systems Modeling Language. Morgan Kaufmann / The OMG Press.
Goode, H. and R. Machol. 1957. Systems Engineering: An Introduction to the Design of Large-Scale Systems. New York, NY, USA: McGraw-Hill.
McKean, R. 1958. Efficiency in Government Through Systems Analysis. New York, NY, USA: John Wiley and Sons.
Mumford, L. 1961. The City in History. San Diego, CA, USA: Harcourt Brace Jovanovich.
Rechtin, E. 1991. Systems Architecting. Upper Saddle River, NJ, USA: Prentice Hall.
Rechtin, E. and M. Maier. 1997. The Art of Systems Architecting. Boca Raton, FL, USA: CRC Press.
Taylor, F. 1911. The Principles of Scientific Management. New York, NY, USA and London, UK: Harper & Brothers.
Vitruvius, P. (transl. Morgan, M.) 1960. The Ten Books on Architecture. North Chelmsford, MA, USA: Courier Dover Publications.
Warfield, J. 1956. Systems Engineering. Washington, DC, USA: US Department of Commerce (DoC).
Wellington, A. 1887. The Economic Theory of the Location of Railroads. New York, NY, USA: John Wiley and Sons.
Wiener, N. 1948. Cybernetics or Control and Communication in the Animal and the Machine. New York, NY, USA: John Wiley & Sons Inc.
Wymore, A. W. 1977. A Mathematical Theory of Systems Engineering: The Elements. Huntington, NY, USA: Robert E. Krieger.
Primary References
Bertalanffy, L. von. 1968. General System Theory: Foundations, Development, Applications. New York, NY, USA: George Braziller.
Boehm, B. 2006. "Some Future Trends and Implications for Systems and Software Engineering Processes." Systems Engineering. Wiley Periodicals, Inc. 9(1), pp 1-19.
Checkland, P. 1981. Systems Thinking, Systems Practice. Hoboken, NJ, USA: Wiley, 1981.
INCOSE Technical Operations. 2007. Systems Engineering Vision 2020, version 2.03. Seattle, WA: International Council on Systems Engineering, Seattle, WA, INCOSE-TP-2004-004-02.
INCOSE. 2012. Systems Engineering Handbook: A Guide for System Life Cycle Processes and Activities, version 3.2.2. San Diego, CA, USA: International Council on Systems Engineering (INCOSE). INCOSE-TP-2003-002-03.2.
Warfield, J. 1956. Systems Engineering. Washington, DC, USA: US Department of Commerce (DoC). Report PB111801.
Warfield, J. 1976. Societal Systems: Planning, Policy, and Complexity. New York, NY, USA: John Wiley & Sons.
Wymore, A. W. 1977. A Mathematical Theory of Systems Engineering: The Elements. Huntington, NY, USA: Robert E. Krieger.
Additional References
Churchman, C.W., R. Ackoff, and E. Arnoff. 1957. Introduction to Operations Research. New York, NY, USA: Wiley and Sons.
Forrester, J. 1961. Industrial Dynamics. Winnipeg, Manitoba, Canada: Pegasus Communications.
Goode, H. and R. Machol. 1957. Systems Engineering: An Introduction to the Design of Large-Scale Systems. New York, NY, USA: McGraw-Hill.
Hitchins, D. 2007. Systems Engineering: A 21st Century Methodology. Chichester, England: Wiley.
McKean, R. 1958. Efficiency in Government Through Systems Analysis. New York, NY, USA: John Wiley and Sons.
The MITRE Corporation. 2011. "The Evolution of Systems Engineering." The MITRE Systems Engineering Guide. Accessed 8 March 2012 at [[1]].
Rechtin, E. 1991. Systems Architecting. Upper Saddle River, NJ, USA: Prentice Hall.
Sage, A. and W. Rouse (eds). 1999. Handbook of Systems Engineering and Management. Hoboken, NJ, USA: John Wiley and Sons, Inc.
Taylor, F. 1911. The Principles of Scientific Management. New York, NY, USA and London, UK: Harper & Brothers.
Vitruvius, P. (transl. Morgan, M.) 1960. The Ten Books on Architecture. North Chelmsford, MA, USA: Courier Dover Publications.
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