Supply-demand processes take place on a large variety of real-world networked systems ranging from power grids and the internet to social networking and urban systems. In a modern infrastructure, supply-demand systems are constantly expanding, leading to constant increase in load requirement for resources and consequently, to problems such as low efficiency, resource scarcity, and partial system failures. Under certain conditions global catastrophe on the scale of the whole system can occur through the dynamical process of cascading failures. We investigate optimization and resilience of time-varying supply-demand systems by constructing network models of such systems, where resources are transported from the supplier sites to users through various links. Here by optimization we mean minimization of the maximum load on links, and system resilience can be characterized using the cascading failure size of users who fail to connect with suppliers.

We consider two representative classes of supply schemes: load driven supply and fix fraction supply. Our findings are: (1) optimized systems are more robust since relatively smaller cascading failures occur when triggered by external perturbation to the links; (2) a large fraction of links can be free of load if resources are directed to transport through the shortest paths; (3) redundant links in the performance of the system can help to reroute the traffic but may undesirably transmit and enlarge the failure size of the system; (4) the patterns of cascading failures depend strongly upon the capacity of links; (5) the specific location of the trigger determines the specific route of cascading failure, but has little effect on the final cascading size; (6) system expansion typically reduces the efficiency; and (7) when the locations of the suppliers are optimized over a long expanding period, fewer suppliers are required. These results hold for heterogeneous networks in general, providing insights into designing optimal and resilient complex supply-demand systems that expand constantly in time.

Topsy is an online analytical tool that evaluates millions of archived and real-time tweets based on their relevancy to a specific criterion. This report studies what Topsy considers relevant, how to create a relevant tweet, the accuracy of Topsy’s relevancy score and whether Topsy is an acceptable tool for use in gauging class participation. After thorough investigation, Topsy was determined to be a great analytical tool for monitoring Twitter participation, yet lacks the fundamental ability to distinguish between tweets relevant to coursework and tweets relevant to everything else.

This project is developing and testing a new approach to teaching engineering and science students that leverages their interest in experiment and experience. Unlike a traditional liberal arts pedagogy involving reading about ethics, discussing the readings, and writing new analyses, this pedagogy uses games to position students in a series of potentially adversarial relationships that force them to confront some of the salient problems of sustainability, including environmental externalities, the Tragedy of the Commons, weak vs. strong sustainability and intra-generational equity. Recent tests allow students at different universities to play the games simultaneously using information communication technologies (ICT). In each game, students must ask themselves the questions related to moral cognition , "What are my obligations to my fellow students?” and moral conation, “What am I willing to risk in my own sense of well-being to meet these obligations?" We hypothesize that this approach will result in students that are actively engaged in learning exercises, and result in an improved ability to identify ethical problems, pose potential solutions, and participate in group deliberations with regard to moral problems.

This poster, first presented at the National Academy of Engineers Frontiers of Engineering Education workshop in Long Beach CA in Oct 2012, explains the necessity of developing engineering cognition, affection, and conation by completing the whole Kolb Learning Cycle. It emphasizes experience and reflection as essential, but overlooked, aspects engineering education with the potential to create transformation of the student.