Abstract:

Once again, we present in this issue nine papers. First seven of them are part of the special issue guest-edited by Professor Joh Tadashi Dohi of Hiroshima University, Japan and Professor Won Young Yun, Pusan National University, South Korea.
Realizing the importance of the subject of Stochastic Modeling and Optimization Techniques, in performance assessment of large complex systems, when Professor Dohi approached me for bringing out a special issue of International Journal of Performability Engineering on this this subject, in which some recent results can be presented, I readily agreed to his suggestion We hope the readers of this journal will find some ideas and approaches useful for them on the subject of system performability analysis.

Only five papers (50 % of those presented) were selected from the papers presented at a special session on Stochastic Reliability Modeling and Optimization organized by the Guest Editors at the Conference QR2MSE 2014 which was held in Dalian, China, on July 22-25, 2014. These papers were invited from the authors based on the significance and discussion that followed the presentation of their papers at this conference and the authors were asked to submit an extended version of their papers for the special issue of International Journal of Performability Engineering. In addition to the five papers selected, two more papers were invited by the Guest Editors from well-known researchers which in their opinion would be supplementing the theme. All papers were once again peer-reviewed and revised based on the comments of the referees following the IJPE norms. The result of this exercise is before the readers. We would welcome comments from the readers of IJPE and researchers to initiate an academic discussion on the papers included in this special issue.

In addition to the above seven papers of the special issue section, we have included two more papers from the regular stream of IJPE.

The eighth paper, of this issue, Economic, Robust and Quality Design of Engineering Systems using a Hybrid Six Sigma-second Moment Approach, the authors claim to present a new approach to allocate means and tolerances while designing engineering systems Useful features of second-moment methods and design for Six Sigma methods are combined. The approach presented obviates the shortcomings of Taguchi’s expected loss function and the need to integrate over the failure region in probabilistic methods.

The ninth paper, Application of ANN to Monitor the Correlated Process using Higher Sample Size, claims that the modified chart, based on sum of chi-squares theory is able to counter the autocorrelation in the observations. Various optimal schemes of modified chart for sample size (n) of 10 are proposed at different levels of correlation (F). The ARLs of the modified chart are also validated and compared with the ARLs obtained by Artificial Neural networks (ANNs).

Besides these nine papers included in this issue, reviews of two latest books are provided in this issue for the benefit of IJPE readers.

I would like to express my sincere thanks to the Guest editors for making all the efforts to bring out the special issue and I also like to thank reviewers who helped us in this task of selecting papers. My thanks are also due to all the authors whose contributions are included in this issue.