Dr. Satoshi Mizutani has interests of optimal maintenance policies in reliability theory such as inspection policy for computer systems and replacement policy for natural disaster. He has shown the several numerical examples of optimal replacement and checking times. His research for optimal maintenance and inspection policies has been published in Reliability Engineering & System Safety, International Journal of Reliability, Quality and Safety Engineering, Computers & Mathematics with Applications, and so on. Dr. Mizutani is a member of Nagoya Computer and Reliability Research organized by Professor Toshio Nakagawa in Japan.Professor Xufeng Zhao is interested in probability theory, stochastic process, reliability and maintenance theory, and applications in computer and industrial systems. He has published two books in maintenance theory from Springer and more than seventy research papers in peer-reviewed journals, and he is the author or co-author of twelvechapters from Springer and Wiley, etc. He has obtained one best paper award from IEEE Reliability Society Japan Chapter and five best paper awards from international conferences in reliability, maintainability, and quality. Professor Zhao serves as an associate editor for Stochastic Models, that is an affiliated publication of INFORMS, and the editorial board and guest editors of other journals. He also severs as a program chair for ISSAT International Conference on Reliability and Quality in Design.Professor Toshio Nakagawa has already published more than two hundred research papers on subject of maintenance and reliability theory in main reliability journals and has published five books titled on “Maintenance Theory in Reliability” in 2005, “Shock and Damage Models in Reliability Theory” in 2007, “Advanced Reliability Models and Maintenance Policies” in 2008, “Stochastic Processes with Applications to Reliability Theory” in 2011, “Random Maintenance Policies” in 2014 from Springer, and so on. His research group in Nagoya has continuously studied reliability and maintenance theory and their applications since 1988 and has published a large number of papers in reliability journals and at international conferences.