Systems Engineering of Cyber-Physical Systems: An Integrated Education Program

Mark Andreessen “Software is eating the world”. [1] Elon Musk: “We really designed the Model S to be a very sophisticated computer on wheels,”.... “Tesla is a software company as much as it is a hardware company. A huge part of what Tesla is, is a Silicon Valley software company. We view this the same as updating your phone or your laptop.” [2] Increasingly, products, systems, and infrastructure in sectors that include transportation (aviation, automotive, rail, and marine), health care, manufacturing, and electrical power generation and distribution are cyber-physical systems (CPS). These systems use integrations of computation, networking, and physical processes to provide key functionality and value. The effective development of these systems often will depend on engineers skilled in cyber-physical systems engineering—trained in the analysis, modeling, implementation and testing of systems in which collaborating computational elements control physical entities and real-time processing plays a critical role. In this paper, we describe an experiential program for graduate studies that provides engineers with the critically important knowledge and skills needed for the design and development of Cyber-Physical Systems (CPS). 1 background Based on a 2015 National Academy of Science preliminary report [3] “Cyber-physical systems (CPS) are increasingly relied on to provide functionality and value to products, systems, and infrastructure in sectors including transportation (aviation, automotive, rail, and marine), health care, manufacturing, and electrical power generation and distribution. CPS are smart, networked systems with embedded sensors, computer processors, and actuators that sense and interact with the physical world (including people), support real-time, guaranteed performance and are often found in critical applications. As CPS become more pervasive, so too will demand for a workforce with the capacity and capability to design, develop, and maintain them.” While Systems Engineering (SE) education has dealt with the specification, design, development and evolution of many types of systems from very large systems for infrastructure, transportation, health care, manufacturing and military projects to very small embedded systems in these same areas, the particular juxtaposition of capabilities of CPS forces the systems engineer to simultaneously balance the demands of communicating physical entities controlled by real-time or near-real-time computation operating with and on behalf of human and system actors. Moreover, to effectively system engineer CPS, this very broad integration of cyber capabilities must be part and parcel of the entire system development cycle, from inception through specification, design and development, validation and evolution. The education challenge is not trivial. Engineers of cyber-physical systems require systems engineering skills that extend across a very broad range of technologies. Our objective with the Systems Engineering of Cyber-Physical Systems program we have developed is to build a series of courses that can satisfy these needs, in effect integrating the skills of hardware, software and systems engineering, for all of these are required to various degrees by everyone on the CPS team. This same approach may be applicable to all of systems engineering, and this can serve as an exemplar as we update our core SE curriculum. 2 educational gaps to be addressed The authors of this paper believe that the real issue is not so much what do CPS engineers need to know, but rather how do they need to think and what do they need to know how to do. In addition, it is critical that engineers of all systems, particularly CPSs, have skills in navigating the entire lifecycle, particularly the conceptual front-end of the development program, the verification and validation, through manufacturing and sustainment which are often neglected in traditional, single-discipline academic engineering programs focused on design and implementation. Again, this is reinforced by the findings of the NAS report [3] as noted below: “Norman Fortenberry, American Society for Engineering Education, described some of the attributes expected of modern engineers: flexibility to manage rapidly evolving technologies; an ability to define as well as solve problems; skill and experience with creativity, entrepreneurship, and public policy implications; and facility with both theory and application.” “... although traditional undergraduate curricula cover the fundamentals of math and science, programming, and problem solving well, they do less well with applications, software engineering, and problem identification.” “... few universities seemed to be emphasizing missionor safety-critical systems and that hands-on project work tends to ignore properties like fault tolerance and robustness.” “...there is a focus on developing new functions over understanding the tools and techniques needed to test and maintain current systems.” “... project-based learning should be integral to any CPS curriculum. Students need to work on complex interdisciplinary projects that encourage systems-level thinking. Doing so requires test beds that allow for the co-design of physical and computational components that demonstrate the benefits of integrating simulation and experimentation. ... design studios, where students can work on integrative CPS projects with multidisciplinary teams, are important.” “Several speakers stressed the value of hands-on projects. Philip Koopman, Carnegie Mellon University, noted that the tools needed to provide students with this experience must incorporate the challenges of large-scale systems and are often expensive and require frequent technology refreshes. Koopman also explained that developing problems that represent the complexity of CPS is difficult. Projects and problems must be realistic and motivating but also incorporate domain knowledge that is accessible to students. There is a risk that problems can become overly complicated—projects must be designed with the right amount of ‘messy’.” The National Institute of Standards and Technology (NIST) Foundations for Innovation in Cyber-Physical Systems report [4] as well as the European ARTEMIS Research agenda [5] points out similar needs across many CPS domains. The NIST report identifies 21 barriers and challenges for CPS reliability, safety, and security. In the top rated category of Metrics and Tools for CPS Verification and Validation (V&V), they cite challenges such as the need for increasing coverage of verification and validation while reducing costs, coping with complexity and scale of systems when performing verification and validation, and the inability to apply formal methods at appropriate abstraction levels, especially for a typical engineer. The Embedded Systems Survey found that university professional development courses came in 8th place with respect to the respondents’ self-assessment of effectiveness. Only 18 percent believed that such courses were effective compared to 43 percent for online training courses. The amount of self-reported training per year decreased almost 25 percent from 2012 to 2013 from 11.7 days to 9 days. It would appear that University degree programs and continuing education are missing the mark. It is the authors’ belief that academic courses do not provide experiences that can be readily applied at the workplace due to the many differences between the academic and workplace contexts. Providing relevant experiences is a critical aspect of the new pedagogical movement around connected learning such that students are able to make the intellectual leap to directly apply what they have learned in the workplace. 3 program objectives and philosophy Stevens Institute of Technology is one of several graduate schools in the USA offering Master of Systems Engineering degrees (as well as Ph.D.s in Systems Engineering). The Master’s degree is considered a professional degree, typically pursued by students with undergraduate degrees in various engineering fields such as civil, mechanical, electrical and software engineering as well as individuals working in engineering and/or large-scale operations roles. The Systems Engineering Master’s degree blends technical and management training to prepare systems engineers for positions of increasing responsibility. Upon graduation, students are well prepared to address systems integration and life cycle issues, and can apply systems thinking at the system, systems of system and enterprise levels. Among the ten courses taken for this degree are required courses in systems fundamentals (focused on front-end processes such as problem definition and requirements), system architecture and design, systems integration and project management of complex systems. Additionally, students must take a course in either modeling and simulation or design for system reliability, maintainability and supportability, or decision and risk analysis. The curriculum balances theory and practice giving students the opportunity to work on real-world problems in a variety of areas. Classical systems engineering relies on functional decomposition in its understanding and design of systems. The software-intensive nature of cyber-physical systems challenges this approach, thoroughly blending hardware, software, networking and human interactions, making decomposition irrelevant to the advancement of system understanding. With embedded software systems at their core, cyber-physical systems require a more integrated approach to the systems engineering life cycle. Our objective was to develop a Systems Engineering of Cyber-Physical Systems program targeting practicing embedded and CPS engineers, to endow them with systems engineering capabilities. This program is projected to include a Master’s Degree, beginning with a fourcourse Graduate Certificate, and a four-hour executives workshop, all sharing a common set of