1. Bradley Department of Electrical and Computer EngineeringVirginia Polytechnic Institute and State UniversityBlacksburgVA24061USA
2. Virginia Electric and Power Company (d/b/a Dominion Virginia Power)RichmondVA23219USA
3. Network Dynamics and Simulation Science LaboratoryVirginia Bioinformatics Institute, Virginia Polytechnic Institute and State UniversityBlacksburgVA24061USA