Computer Science Department, Purdue University, West Lafayette, IN, USA.|IBM Research, Thomas J. Watson Research Center, Yorktown Heights, NY, USA.|Computer Science Department, Purdue University, West Lafayette, IN, USA.|Computer Science Department, Purdue University, West Lafayette, IN, USA.|Department of Biological Sciences, Purdue University, West Lafayette, IN, USA.|Computer Science Department, Purdue University, West Lafayette, IN, USA.