Systems engineering is an interdisciplinary, holistic approach to dealing with large and complex engineering projects through the application of systems theory.1 Within these large projects and systems that are composed of many specialized domains, systems engineering primarily focuses upon systems integration, i.e. the overall architecture through which the many diverse components to a project or technology are integrated into a functioning entirety by providing a systems view of the project.
The development of the definition of systems engineering has been a subject of some controversy and the term continues to be applied in both a narrower definition (as an extension of traditional engineering dealing primarily with physical technologies through a reductionist approach) and within a broader scope where it expanded the concept of engineering to include both physical technologies, social systems and the interaction between the two, what are called Socio-Technical Systems (STS).2
The emergence of the domain of systems engineering over the past few decades can be understood as a response to the challenges of engineering functional systems of unprecedented complexity. These complex engineered systems, such as urban infrastructure, enterprise systems, transportation systems and health care systems involve a high degree of both social and technical complexity, a large number of stakeholders, significant technical expertise within many specialized domains, and are enabled by a suite of financial, economic and regulatory contracts and institutions. Systems engineering then tries to bring the high degree of abstraction (provided by systems theory) required for integrating these complex projects into functioning solutions.
Systems engineering (as the name implies) inherits its theoretical foundations from systems theory and forms part of the system sciences, thus it places a greater enforcement upon understanding entities through the complex of relations that give them context within the whole system that they are a part of. Systems engineers apply the model of a system in order to model and integrate the diverse components to complex engineered systems and projects.
The many traditional domains of engineering, from electrical engineering to aerospace engineering are focused on specific areas of interest. But when projects become sufficiently large and diverse, there emerges a requirement for systems integration, and systems engineering performs this function being primarily focused on the coordination between components that results in the overall efficiency of the system.
System engineering is inherently interdisciplinary as complex engineered systems often involve qualitatively different components and require expertise from many different domains. Although systems engineers are not required to have a deep knowledge of all these different areas, they are expected to have a general understanding of them and their functional contribution to the project or system as an entirety.
Whereas the social domain has traditionally been largely excluded from the area of engineering (being focused primarily on technical solutions) systems engineering (taking a holistic perspective) is often concerned with both the social and technical dimension to complex projects and how they interact and work together. The concept of a socio-technical system is then important in that it provides some framework and terminology for modeling and trying to engineer the system on both levels.
The holistic perspective to systems engineering applies not just across domains but also across time as it tries to model and design the system, taking into consideration its full life-cycle. Through life-cycle analysis and life-cycle modeling languages, systems engineers try to examine and address all phases of the system’s existence to include the system conception, design and development, production and/or construction, distribution, operation, maintenance and support, retirement, phaseout, and disposal.
The growth in the domain of systems engineering is often understood as a response to the increased complexity of engineering systems and projects as they have become both larger in scale (exemplified by so-called ‘mega-projects’) and in inter-connectivity (typically due to information technology). Systems engineering employs a large degree of abstraction in order to deal with this complexity through an increased emphases upon models and computer simulation. From Systems Modeling Language (SysML) to Decision Matrix, a wide variety of standardized modeling methods and languages are employed.