National Engineers Week: A Q&A with Olivier de Weck

On engineering systems and the book Engineering Systems: Meeting Human Needs in a Complex Technological World


To celebrate National Engineers Week (February 19-25), MIT Press has conducted a series of Q&As with the authors of the new Engineering Systems series books.

First is Olivier L. de Weck, author (with Daniel Roos and Christopher L. Magee) of Engineering Systems: Meeting Human Needs in a Complex Technological World. He is associate professor of aeronautics and astronautics and engineering systems; executive director of the MIT Production in the Innovation Economy (PIE) study; and co-director of the Center for Complex Engineering Systems at KACST and MIT.

Q. What is an "engineering system"?

A. An engineering system is a system that has both a high degree of technical or technological complexity as well as social complexity and where both of these complexities are intertwined in a way that makes them inseparable.

It's a system designed/evolved by humans having some purpose; it is large scale and complex and will have a management or social dimension as well as a technical one. Examples of engineering systems are the electrical grid, our road, rail and air transportation networks, and the internet. Today, most of our needs as human beings for things such as water, food, medical care, and education are being met by complex engineering systems. Many of us don't realize how intricate the underlying systems have become when we open the water tap, take a prescribed medication, or buy food at our local grocery store.

Q. How does engineering systems differ from "traditional" engineering?

A. Traditional engineering is often explained as the harnessing of mathematics and physical laws from the underlying natural sciences such as physics, chemistry, and biology to design and produce artifacts that solve useful problems and are embodied by particular technologies. Of course engineering is very much associated with these activities, but we believe that engineering has a larger role to play in society. The engineering systems described above are not simply artifacts that require technology, but they are intricate networks of hardware, software, natural elements, and human actors that interact in complex and sometimes surprising ways. One of the key aspects is that policies and regulations underline the way in which these systems are operated and evolved. Therefore, engineering must not only tackle the technological part of the design but also the social, regulatory part of system design. Rather than solving problems in different disciplinary silos, new integrated approaches are needed. Traditional engineering and the engineering systems approach are not at odds with each other — engineering systems is a broader interpretation of what engineering is and should be.

Q. How is the language used by engineers and the language used to describe what they do changing?

A. The traditional engineering concepts based on physical laws such as mass, force, momentum, charge, energy, performance, stability, efficiency, etc., continue to be very important. If the products and systems produced by engineers don't meet basic functional requirements and constraints in the end, then a viable solution has not been obtained. However, achieving technical feasibility or even optimality may no longer be enough. Increasingly, technical systems have to satisfy challenging lifecycle requirements such as being environmentally and economically sustainable, being easy to change to new circumstances, or being able to inter-operate with other systems and by a large range of human users that were not initially considered. The new language of engineers focuses increasingly on more abstract concepts such as complexity, system architecture, modularity, evolvability, regulatory compliance, policy robustness, and resilience. One of the reasons for this trend is that the world is changing at an increasingly fast pace and that, especially since 2001, we have become more aware of unintended consequences and vulnerabilities in engineering systems that are triggered by natural disasters and man-made attacks.

Q. Can you briefly tell us about the "(re)visioning perspective" framework that you set out in the book?

A. The (re)visioning framework is a holistic way in which engineering systems can be viewed, models, analyzed and ultimately understood. First, we need to define the scale and scope of the system that we seek to analyze. Next, we ask what the key functions are that the system should perform, followed by mapping the relationship between the structural elements that make up the physical manifestation of the system. Finally, we want to understand how the system behaves dynamically — both at short time scales (seconds, minutes, hours, days) and at longer time scales (weeks, months, years, decades). The elements of the (re)visioning perspective challenge everyone who works on an engineering system. To understand an engineering system, and hence to improve it or address problems with it, requires a careful assessment of the system's scale and scope, its function (or functions, since a system may have more than one), its structure (or architecture), and — because, as we would expect of a system that is partially designed and partially evolved, it is dynamic and changes over time — its temporality.

None of these can be divorced from how the system's social complexity and social effects are understood. The interactions within these large-scale complex sociotechnical systems as well as their interactions beyond the system boundaries raise yet more challenges. Engineering systems have complex causation relationships, and analysis of complex engineering systems must rest on the foundation of bidirectional causation, considering all the feedback relationships that exist.

Q. What are the dangers of ignoring the (re)visioning perspective?

A. There are a couple of things that come to mind immediately. The first is the danger of linear thinking, leading to simple extrapolation of trends into the future. Engineering systems may have very non-linear elements and feedback mechanisms leading to the potential for unexpected and non-intuitive behaviors like instabilities and failure cascades, saturation effects, or super-linear growth, as well as unexpected compensation behaviors when major failures or disruptions occur. A more fundamental danger is that the system boundary is chosen too narrow or too broad and that suggested improvements may not really work because the key levers for improvements are located elsewhere.

One of my favorite examples is the attempt to reduce congestion and pollution in Mexico City by only allowing cars with odd or even-numbered license plates to drive on any given day. Human ingenuity found many workarounds (such as purchasing a cheaper older car), ultimately undermining the intended effects of the policy.

Q. In Chapter 4, you discuss the top "four ilities" of traditional engineering — quality, maintainability/reliability, safety, and flexibility — and state that engineering systems has made this list of "ilities" much longer. Why is that, and what would you consider to be the top four "ilities" of the engineering systems epoch?

A. We analyzed the prevalence of these lifecycle properties in the engineering literature going back all the way to 1884. It became clear to us that the classical engineering "illities" such as quality, safety, and reliability were essential in making artifacts such as cars, power stations, trains, and telephones work reliably and predictably. Then, during and after World War II, we detect a major shift as we entered the Epoch of Complex Systems. During the war, it was essential to produce systems effectively at a large rate; therefore, the concept of scalability and usability of weapons systems was a major factor driving success on the battlefield. Usability and the field of human factors was invented and subsequently drove major design considerations for commercial products and systems. Starting in the 1970s concern over environmental impacts and interoperability of military systems, as well as the development of the internet, gave rise to new system properties such as sustainability and interoperability, which continue to be of major interest today. Also, due to the unpredictability and rate of uncertainty in today's world, the desire for flexibility in systems continues to increase. One of the big challenges is to develop principles, methods, and tools for designing systems to be deliberately imbued with these properties with a level of rigor and predictability that is commensurate with that of the more traditional engineering properties. It also true that system properties that were once thought to have been masters, such as safety, must now be revisited due to the increasing sociotechnical complexity of today's systems.

Q. What do you mean by "partially designed, partially evolved"? How does this concept apply to the MBTA?

A. We usually think that engineers and designers have full control over their own inventions and creations. This may be true for smaller scale artifacts like watches, toasters, and cars; however, large scale engineering systems have lifetimes of decades or centuries. Over these long time periods the underlying demographics of users, economics, political imperatives, and natural environment may change in ways that were never considered by the original designers. Thus, parts of the system may be shut down or modified and new elements may be added in time. These patterns resemble more biological evolutionary processes rather than follow the initial plan laid out by a master designer. In terms of the MBTA (Boston's local transit system) I would like to mention the creation of the Silver Line, an innovative bus line that uses mostly dedicated lanes and tunnels and serves the airport and rapidly evolving waterfront district in South Boston. This is intimately connected to the Central Artery ("Big Dig") project that we discuss in the book. Did the original designers of Boston's first electric street car in 1889 envision the Silver Line? Most certainly not. The system evolved over time as new elements were added to better serve the rapidly evolving city.

Q. What are the "enablers of success" as engineers address the engineering systems challenges that face humanity?

A. This is a great question. The first thing that comes to mind is humility. Engineers must become aware not only of the intended consequences of their designs but also of the unintended consequences and the larger set of forces that will promote or inhibit the adoption of new technologies or "solutions" to pressing problems. Taking a broad socio-technical perspective, while preserving or deepening our understanding of the technical and social possibilities, is essential. The (re)visioning perspective is a useful initial starting point for organizing the thinking around large scale challenges of our time. There are examples of successes in taking this perspective, such as the transformation of IBM from a manufacturer of business machines to a provider of integrated business solutions and services; the innovative approach to transportation in cities such as Curitiba, Brazil; and the progress Australia has made in managing its scarce freshwater resources.

Success depends on the barriers being broken down that today keep engineers, social scientists, and management scientists from teaming together in the most effective way to address the world's problems. These barriers include the mental models those in various disciplines carry with them throughout their careers, the institutional obstacles that exist in academia and even in the business world, and the lack of understanding about what other disciplines might bring to the table (something we hope our book will make at least a small contribution to correcting).

Q. Using MIT as an example, how has the focus of engineering education changed over time?

A. MIT has been and continues to be one of the leaders in engineering education. After the adoption of the engineering science approach after World War II (most of the big breakthroughs were led by trained physicists, not by engineers), engineering was refocused on the fundamentals of mathematics, physics, chemistry, and the other underlying natural sciences. Starting in the late 1980s and early 1990s, there was a realization that MIT needed to also directly impact industry and government practice, which led to the creation of new programs that integrated aspects of engineering with management and, to a lesser extent, with the social sciences. Degree programs such as System Design and Management (SDM), Leaders for Manufacturing (LFM) — now Leaders for Global Operations (LGO) — and the Engineering Systems Division (ESD) were driven by the need for a new and broader approach to engineering. Another example is the lifecycle-oriented curriculum known as CDIO (conceive-design-implement-operate) in Aeronautics and Astronautics, as well as the recent Gordon Engineering Leadership (GEL) program in the School of Engineering. One of the most difficult questions is how to provide a deep foundation in fundamentals while also exposing engineering students to the most important concepts (such as cost analysis, strategy, material selection, supplier sourcing, regulatory science) that often dominate engineering practice in the real world. Much work remains to be done, also at MIT.

Q. What kinds of changes (if any) do you think we need to make in engineering education?

A. This may sound radical, but I think the time has come to fundamentally rethink the need for traditional departments. The distinctions between mechanical, electrical, chemical engineering , etc. are largely historical and a vestige of the past. Most of the systems and products being designed in the 21st century have a complex mix of mechanical, electrical, chemical, biological, and other cyber-physical elements and are designed for a large variety of human users. While engineers clearly must develop areas of deep expertise, it is not clear to us that this has to be done around the historically evolved stovepipes. It is interesting that none of the new universities that MIT is helping to get off the ground — such as Masdar Institute in Abu Dhabi, SUTD in Singapore, and SkTech in Moscow — have departments. They all have at their core an integrated modern curriculum that is centered on pillars or problem areas that map to large scale socio-technical challenges rather than to a set of clearly delineated governing equations such as the Navier-Stokes Equations (fluid dynamics), Maxwell's Equations (Electrical Engineering), or the Shannon-Hartley Law (Information Theory).

Engineering education must change as was also articulated in the well-known Engineer 2020 report released by the National Academy of Engineering. In the book we argue that "Engineering education, which since its early days has enjoyed a rich history, today has begun to broaden from preparing students for technical careers to educating technically grounded leaders who will run complex systems and enterprises and establish new entrepreneurial startups." We believe that the engineering systems concepts we discuss are an important step in that direction.


Topics: Aeronautical and astronautical engineering, Books and authors, Engineering Systems, Faculty, MIT Press, Production in the Innovation Economy (PIE)

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