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The " traditional " way of designing constellations of communications satellites in low Earth orbit is to optimize the design for a specified global capacity. This approach is based on a forecast of the expected number of users and their activity level, both of which are highly uncertain. This can lead to economic failure if the actual demand is(More)
This paper describes the concept of Time-Expanded Decision Networks (TDNs), a new methodology to design and analyze flexibility in large-scale complex systems. This includes a preliminary application of the methodology to the design of Heavy Lift Launch Vehicles for NASA's space exploration initiative. Synthesizing concepts from Decision Theory, Real(More)
Understanding how and why changes propagate during engineering design is critical because most products and systems emerge from predecessors and not through clean sheet design. This paper examines a large data set from industry including 41,500 change requests that were generated during the design of a complex sensor system spanning a period of 8 years. In(More)
This paper is a summary of topics presented and discussed at the 2006 European–U.S. Multidisciplinary Optimization (MDO) Colloquium in Goettingen, Germany, attended by nearly seventy professionals from academia, industry, and government. An attempt is made to accurately reflect the issues discussed by this diverse group, qualified by interest, experience,(More)
Designing a large-scale complex system, such as a city of the future, with a focus on sustainability requires a systematic approach toward integrated design of all subsystems. Domains such as buildings, transportation, energy, and water are all coupled. Designing each one in isolation can lead to suboptimality where sustainability is achieved in one aspect(More)
This paper examines the optimization of wireless sensor network layouts. To transmit their data to the base, all the sensors are required to be connected to a high-energy communication node, which serves as a relay from the ground to a satellite or to a high-altitude aircraft. The sensors are assumed to have a fixed communication and a fixed sensing range,(More)