Department of Computer Science, Rice University, 6100 Main Street, MS 132, Houston, TX, USA. cvthan@cs.rice.edu|Department of Computer Science, Rice University, 6100 Main Street, MS 132, Houston, TX, USA. cvthan@cs.rice.edu|Department of Computer Science, Rice University, 6100 Main Street, MS 132, Houston, TX, USA. cvthan@cs.rice.edu