Lee. Special thanks to Kaushik Gala for proofreading this thesis, and to Vara Varavithya for helping me with various formalities of thesis submmition. Thanks to Andrew, Jerry, Idarto, Chimai and other "sysadmin" people for keeping the computers up and running. I am grateful to National Science Foundation, Lucent Technologies and Design Automation Conference for fimding parts of my research; TKF.F. and Iowa State University for providing financial support to attend conferences; and IBM for providing me with the opportunity to work two summers. I feel indebted to my aunts, uncles and cousins in US for their love and emotional support and for many wonderful vacations; eind to my parents for having faith in me.