1. University of Tennessee,Dept. of Electrical Eng. and Computer Sci.,Knoxville,TN,USA,37996
2. Princeton University,Dept. of Physics,Princeton,NJ,USA,08544
3. Rochester Institute of Technology,Dept. of Electrical and Microelectronic Eng.,Rochester,NY,USA,14623
4. Pennsylvania State University,School of Electrical Eng. and Computer Sci.,University Park,PA,USA,16802