In this issue, we have included 10 papers presenting interesting research or case studies on different aspects of performability engineering. Generally, we always had more number of papers from researchers outside India than from India. This is the first issue in which papers from outside India and from India are equally distributed signifying keen interest in the area..
The literature in the past has focused primarily on reliability evaluation based on single node pair capacity requirements. In the first paper from India, a new reliability measure, as multi node pair capacity related reliability (MNPCRR), and an algorithm to evaluate this measure are proposed. This measure, authors claim is expected to help network designers in assessing and optimizing network performance and its effectiveness.
Embedded OSS is gaining a lot of importance these days, particularly for application with Android, Busybox but it presently suffers from quality and customer problems. So the second paper from Japan presents an approach for assessing software reliability based on flexible hazard rate model and formulates a total expected software cost model considering the environment for the usage of mobile device.
The third paper from Jordan attempts to investigate the critical factors and issues that are responsible for poor performance of existing software reliability models. The author identifies reasons attributable to 14 flaws which inhibit the improvement of software reliability modeling.
The fourth paper from India, tries to develop a list of Critical Success Factors for TQM implementation in Indian industries by doing a comparative study of 21 major 'National Quality Awards' and 14 frameworks as developed by various researchers. Then, using Principal Component Analysis, the paper proposes a new model for TQM implementation, which authors claim can help achieve manufacturing excellence and enhance competitive abilities of the industries.
The fifth paper jointly from Australia and U.S.A. presents a dynamic programming (DP) scheme to solve the problem of designing a network topology with maximum (s, t) reliability subject to given constraints, such as the computer centers location (nodes), their connecting links reliability and cost, and the maximum budget cost to install the links and suggests five different path-orders are proposed to improve the effectiveness of DPA.
Security authentication verifies the identity of an entity in a networked system. Risk assessment of an authentication mechanism is paramount to assure the security of a system. Though performability engineers have extended model-based evaluation techniques to assess security attributes such as system availability, confidentiality, and data integrity, authentication has so far not been found any connections to classical dependability measures. The sixth paper from U.S.A. presents a predictability model to quantify the risk of authentication violations. A RFID-based Electronic Toll Collection (ETC) system, demonstrates that the approach provides a useful metric.
The seventh paper from India presents reliability computation of a rotary system where reliability not only depends on the static design stresses but also on dynamic forces generated during operation by factors such as imbalance, misalignment, oil whirl, bend shaft, mechanical looseness etc. A model is proposed to incorporate the effect of imbalance mass on the reliability of rotary systems. The effect of rotating speed on reliability can also be assessed by this model.
The eight paper from U.S.A. presents an approach to validate computational models in the design space under uncertainty. The idea is to first characterize the model bias; then correct the original model prediction by adding the characterized model bias in the design space. A two-step calibration procedure is proposed and the model bias at each design configuration is approximated using the Maximum Entropy Principle (MEP) method.
The ninth paper is from an Indian private business entity representing ReliaSoft presents basically a tutorial case study on a compressor to demonstrate how their organization can help in reliability and maintainability studies.
The tenth paper also from India presents a case study on availability evaluation using Markov approach for a typical coal-fired power plant and identifies critical sub-systems and indicates plans for the preventive maintenance schedule.
In the end, I would like to thank all the authors who have contributed to this issue. I also like to record my appreciation and special thanks to all the anonymous referees who refereed papers and cooperated in maintaining the time schedule.