Department of ECE, Seoul National University, Seoul 151-744, Korea.|Department of ECE, Seoul National University, Seoul 151-744, Korea.|Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA.|Department of ECE, Seoul National University, Seoul 151-744, Korea.|Department of ECE, Seoul National University, Seoul 151-744, Korea, Interdisciplinary Program in Bionformatics, Seoul National University, Seoul 151-744, Korea and.|Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA, Department of Physics, Stanford University, Stanford, CA 94305, USA.