It is a myth that a dissertation is the soul-wrenching creation solely of its author's time, toil and tenacity. Many people conspired to drag this author kicking and screaming towards his goal. I thank these people for conspiring to do so.

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I am thankful to Paul Reynolds, my advisor and friend, for giving me guidance and counsel, and for having faith and confidence in me. His patience in reading draft after draft of every paper, proposal and idea I wrote up continues to amaze me. No one should be subjected to the torture of reading my early attempts at technical writing, and thanks to Paul, no one will. I appreciate Paul's fine balance between giving me the freedom to pursue what fired me and reining in my imagination when it got the better of me. I thank him for always being willing to meet me whenever I barged into his office.

I am grateful to my committee members for their comments and suggestions. I have benefitted greatly from their advice. I thank Worthy Martin and James French for lending a sympathetic ear and putting my toils in perspective. It has been a pleasure working with my colleagues, in particular, Anh Nguyen-Tuong, Rashmi Srinivasa, Sudhir Srinivasan and Glenn Wasson. Many of the ideas in my work originated in discussions with them. I am deeply grateful to them for investing time and energy discussing ideas with me and tolerating my many opinionated digressions. Gabriel Ferrer, John Karro, Allison Powell and Rashmi Srinivasa deserve credit for reading sections of my work. Their incisive comments made me re-think how I presented my ideas. Any errors that remain in this presentation are attributable to my negligence or stubbornness.

I thank the Defense Modeling and Simulation Office, US Army SIMTECH and Janet Morrow for making it possible for me to do my research.

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This dissertation would not have been possible without Rashmi Srinivasa, my wife and friend. Her support and encouragement has seen me through tumultuous times. I thank her for simultaneously brandishing a sword to quell the demons of my insecurities, a spoon to bake delectable desserts and a wand to bring joy to my life in so many different ways.

I thank my parents, Subramanian and Shanta Natrajan, and brother, Arvind Natrajan, for their unflagging belief that despite their incomprehension about what I do, I must be saving the world. I am indebted to my parents for inculcating in me the dedication and discipline to do whatever I undertake well. I cannot thank my brother enough for showing me what it is to be a free spirit.

I have been fortunate to have many friends who cherish me despite my eccentricities. I risk doing them a disservice by not mentioning all of them here, but plead paucity of space. I thank Glenn Wasson for goading me through weight-lifting, imploring me to spike the volleyball, teaching me about baseball and being a sink for my bile during our coffee klatsches . I thank Anh Nguyen-Tuong for letting me ramble about programming languages at three in the morning, putting me in my place at racquetball and being a friend to me in my early days at UVa. I thank Suresh Balasubramaniam, Karine Boulle, Aaron Cass, John Jones, Gopal Kumar, Sally McKee, Venkataraman Pallassana, John Regehr, Prakash Vachaspati, Ravichandran Vancheeswaran, Murtuza Vasowalla, Aruna Viswadoss, Soumya Viswanathan, Chenxi Wang and Jennifer Wong for many good times.

Finally, I am thankful for the many diversions I have enjoyed during my sojourn here. Without them, crossing over to the realms of insanity would have been entirely within reach. My various hobbies, my books, my cooking, and beautiful, beautiful Charlottesville have connived to ensure that the road to my goal was not as bumpy as it could have been.