Conclusion

Following on from the publication of works concerning the concepts, methods, tools and domains of application of systems engineering and system-of-systems engineering and a work on modeling and simulation, the present work goes into greater depth regarding these notions. It the specifies the dimensions of complexity that characterize large-scale systems and shows the application of these notions through two case studies, while highlighting the fact that certain challenges and issues remain.

So, can we take an optimistic view of the current situation?

We should remember that systems engineering, which emerged in the 1950s, benefits from a corpus of material based around advances in cybernetics, information theory and systems theory in more general terms. It is therefore built on unshakeable scientific and mathematical foundations, and on paradigm breaking: from Cartesian principles to principles of cybernetics, teleology, holism, opening, etc. Systems engineering has been progressively enriched by technological and methodological developments throughout its 60 years of existence.

These considerable and sometimes “forgotten” acquisitions and the evolutions of our world mean we are confronted with a number of challenges and issues in terms of mastering complex systems (evolution in the way engineering is taught, organizational developments and the growing place of information processing and management activities mean that an Office suite and an email account are now indispensable in the arsenal of managers and engineers in their daily work). We must integrate the notion of services in the engineering of large-scale complex systems, (re)place architecture in a central role (something seen consistently throughout our two case studies), develop relationships and modes of interaction between stakeholders, and give greater consideration to domains such as the economic and social sciences, etc.

Systems engineering is an approach used to create and then solve complex problems through global and interdisciplinary efforts. The solutions obtained in this way should be optimized to give maximum satisfaction to all stakeholders. The quest for this optimum becomes even more difficult as we must give due consideration to new issues:

– an optimum solution cannot be “fragile”, but must be “sturdy”: this property is obtained through architectural robustness, resilience, insensitivity (or low sensitivity) to context variations, resistance to technological obsolescence and adaptability to new opportunities (whether in terms of technologies, services, economic models, etc.);

– the solution must successfully master new emergences created by the composition, federation, coalition, etc. of systems in a system of systems approach;

– the change in perspective that pushes us towards a “service-oriented” vision leads us to reconsider the notion of value (and thus its optimization), the very approaches used in architectural design, and the place of the human both as an actor participating in the creation of a service and as a user.

So, what is to be done? As we have suggested throughout this work, progress may be made by the development of both processes and methods, while reconsidering the role of the human participant who is, and must remain, a major actor in any engineering approach.

We must learn to integrate notions of resilience, robustness, varying dimensions of complexity, etc., in our approaches.

More generally, we must give consideration to questions of logistics, maintenance, dismantling, sustainable development, etc., in our large-scale complex systems. A necessary (but not sufficient) condition for this is better interoperability between teams and partners. This requires genuine integration and federation of disciplines (with an end to stove-pipe engineering and mutual ignorance between disciplines), the number of which seems to increase on a daily basis.

The effective assimilation of these scientific and technical considerations into our engineering approaches represents a considerable challenge. However, another challenge exists that poses a still greater challenge to our practices.

We need to reinvent the dynamics of the client/user/supplier relationship to move towards co-creation of future architectures and services, including both collaborative engineering and collective management practices. This can only be attained through co-development of such practices by these different stakeholders. The present work, based on case studies and written in collaboration with authors operating professionally on both sides of the mirror, was created with the desire of contributing to this process.