1. Department of Information & Communication Systems, Hohai University, Changzhou 213022, China
2. Guangdong Provincial Key Lab of Petrochemical Equipment Fault Diagnosis, Guangdong University of Petrochemical Technology, Maoming 525000, China
3. Integrated Management Coastal Research Institute, Universidad Politecnica de Valencia, 46000 Valencia, Spain
4. Instituto de Telecomunicações, University of Beira Interior, 6201-001 Covilhã, Portugal