1. School of Electrical Engineering and Computer Science Oregon State University Corvallis OR 97331 USA
2. School of Chemical, Biological, and Ecological Engineering Oregon State University Corvallis OR 97331 USA
3. School of Information Science and Engineering The Key Laboratory for Special Fiber and Fiber Sensor of Hebei Province Yanshan University Qinhuangdao 066004 China
4. School of Electrical Engineering The Key Laboratory of Measurement Technology and Instrumentation of Hebei Province Yanshan University Qinhuangdao 066004 China