Not a mystery any more. Complex Systems Engineering Not a mystery any more. It’s time to put complex systems to work.

Characteristics - structure Multi-scalar –Multiple levels of abstraction (not self-similar). IT systems involve quantum physics, solid-state electronics, gates and gate logic, software, business strategies, … Vulnerable to phase transitions: small change → big effect. –If the system involves real physical stuff … No feasibly simulatable bottom level. Quarks? Strings? –E.g., an evolutionary arms race. The different levels cannot be completely isolated from each other — or we would have magic –except for levels implemented in software. –Allows creative new uses, “emergence.” –Includes “loosely coupled” components with a certain degree of autonomy, e.g., agents. Multi-disciplinary (see levels of abstraction)

Characteristics - environment Entangled with its environment. –Systems are often built to act on their environments—to do something in the world. –Systems are (often) controlled/manipulated by modifying the environments within which they exist. Boundaries are not always clear. –System of systems. The operator goes home at night. Often a multi-sided platform. –Internet, Windows/Mac/Linux OS, game platform, shopping center. Must extract energy from its environment to persist. –“Far from equilibrium.” Requires continual adaptation to a changing environment. –Always under development/evolving, e.g., version x.y. –Is simultaneously deployed and under development, e.g., a wiki. –Must be understood more broadly than as “a deliverable” but as a social entity that also includes its developers and its users.

Our task Clarify and formalize these concepts. Make them intuitive and commonplace. Make them operational. –Adapt them to practice in building real systems. –Build tools to allow anyone to use them.