Systems engineering (SE) is essential to the success of many human endeavors. As systems increase in scale and complexity, SE is increasingly recognized worldwide for its importance in their development, deployment, operation, and evolution. The purpose of the SEBoK is to provide a widely accepted, community based, and regularly updated baseline of SE knowledge. This baseline will strengthen the mutual understanding across the many disciplines involved in developing and operating systems. Shortfalls in such mutual understanding are a major source of system failures, which have increasingly severe impacts as systems become more global, interactive, and critical.
Key terms.
A good first step towards understanding is to define key terms. Four terms will suffice for this Introduction: system, engineered system, systems engineering, and systems engineer.
Here are baseline definitions of what these terms mean for the purposes of the SEBoK:
• A system is “a set of elements and a set of inter-relationships between the elements such that they form a bounded whole relative to the elements around them” (Bertalanffy 1968) and which exists in an environment which contains related systems and conditions. While there are many definitions of the word “system,” the SEBoK authors believe that this definition encompasses most of those which are relevant to systems engineering.
• An engineered system is an open system of technical or sociotechnical elements that exhibits emergent properties not exhibited by its individual elements. It is created by and for people; has a purpose, with multiple views; satisfies key stakeholders’ value propositions; has a life cycle and evolution dynamics; has a boundary and an external environment; and is part of a system-of-interest hierarchy.
• Systems engineering is “an interdisciplinary approach and means to enable the realization of successful systems” (INCOSE 2012). It focuses on holistically and concurrently understanding stakeholder needs; exploring opportunities; documenting requirements; and synthesizing, verifying, validating, and evolving solutions while considering the complete problem, from system concept exploration through system disposal.
• A systems engineer is “a person who practices systems engineering” as defined above, and whose systems engineering capabilities and experience include sustained practice, specialization, leadership or authority over systems engineering activities. Systems engineering activities may be conducted by any competent person regardless of job title or professional affiliation.
Purpose of the SEBoK
The purpose of the SEBoK is to provide a widely accepted, community based, and regularly updated baseline of SE knowledge. This baseline will strengthen the mutual understanding across the many disciplines involved in developing and operating systems. Shortfalls in such mutual understanding are a major source of system failures, which have increasingly severe impacts as systems become more global, interactive, and critical. Ongoing studies of system cost and schedule failures (Gruhl-Stutzke 2005; Johnson 2006) and safety failures (Leveson 2012) have shown that the failures have mostly come not from their domain disciplines, but from lack of adequate SE.
Purpose Description
1 Inform Practice Inform systems engineers about the boundaries, terminology, and structure of their discipline and point them to useful information needed to practice SE in any application domain.
2 Inform Research Inform researchers about the limitations and gaps in current SE knowledge that should help guide their research agenda.
3 Inform Interactors Inform performers in interacting disciplines (system implementation, project and enterprise management, other disciplines) of the nature and value of SE.
4 Inform Curriculum Developers Inform organizations defining the content that should be common in undergraduate and graduate programs in SE.
5 Inform Certifiers Inform organizations certifying individuals as qualified to practice systems engineering.
6 Inform SE Staffing Inform organizations and managers deciding which competencies that practicing systems engineers should possess in various roles ranging from apprentice to expert.
The SEBoK is a guide to the body of systems engineering knowledge, not an attempt to capture that knowledge directly. It provides references to more detailed sources of knowledge, all of which are generally available to any interested reader. No proprietary information is referenced, but not all referenced material is free—for example, some books or standards must be purchased from their publishers. The criterion for including a source is simply that the authors believed it offered the best generally available information on a particular subject.
The SEBoK is global in applicability. Although SE is practiced differently from industry to industry and country to country, the SEBoK is written to be useful to systems engineers anywhere. Authors have been chosen from diverse locales and industries, and have refined the SEBoK to broaden applicability based on extensive global reviews of several drafts.
The SEBoK aims to inform a wide variety of user communities about essential SE concepts and practices, in ways that can be tailored to different enterprises and activities while retaining greater commonality and consistency than would be possible without the SEBoK. Because the world in which SE is being applied is evolving and dynamic, the SEBoK is designed for easy, continuous updating as new sources of knowledge emerge.
Scope and Context of the SEBoK
The SEBoK is one of two complementary products. The other, which uses the content of the SEBoK to define a core Body of Knowledge to be included in graduate SE curricula, is called the Graduate Reference Curriculum for Systems Engineering (GRCSE™). The GRCSE is not a standard, but a reference curriculum to be tailored and extended to meet the objectives of each university’s graduate program.
Most of the SEBoK focuses on domain-independent information—that which is universal to systems engineering regardless of the domain in which it is applied. Part 7 includes examples from real projects. These illustrate the concepts discussed elsewhere in the SEBoK, while detailing considerations relevant to domains such as aerospace, medicine, and transportation. The SEBoK also covers considerations for the disciplines of software engineering and project management, which are strongly intertwined with the practice of SE.
One summarizes the SEBoK’s definition by an international group of volunteer authors; its review by the SE community at large; its life cycle evolution management and support by the two primary international SE-related professional societies, the Institute of Electrical and Electronic Engineers (IEEE) and the International Council on Systems Engineering (INCOSE); and its use in derivative products and services by the community at large.