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Unbiasing Beta for the Crow-AMSAA (NHPP) Model

The Crow-AMSAA (NHPP) model is probably the most popular model in reliability growth and repairable system analysis. With this model, maximum likelihood estimation (MLE) is used to estimate the parameters. However, it is well known that the MLE solution for the shape parameter is biased (i.e., the estimated beta value is too high), which affects the accuracy of the results. This is a particular concern when working with small sample sizes. In this article, we will explain how the bias is corrected in RGA.


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ReliaSoft Recognized at University of Arizona College of Engineering Celebration

The University of Arizona's Department of Systems and Industrial Engineering celebrated their 50th Anniversary and acknowledged the support of ReliaSoft during the Homecoming weekend festivities on November 9 - 11. Doug Ogden, ReliaSoft's Vice President of Customer Service, attended the ceremony and delivered an acceptance speech. The entire staff of ReliaSoft is proud to be a part of the Department's 50th Anniversary celebration! For more details please visit:


SMRP Conference 2012

ReliaSoft participated once again in the Society for Maintenance & Reliability Professionals (SMRP) Annual Conference. We wish to send a special thanks to all the engineers who attended Mr. Claudio Spano's presentation on PAS-55, and we certainly appreciate all the visitors who stopped by our booth. SMRP provides an excellent venue to broaden one's knowledge and expertise, which aligns well with ReliaSoft's goal to expose more engineers to asset performance management supported by reliability engineering.


Congratulations to the 2012 ARS Excellent Presentation Award Winners!

Each year, engineers have the opportunity to present at one of the Applied Reliability Symposium (ARS) events held five times a year at locations around the world. One of the coveted goals for many presenters is achieving an ARS Excellent Presentation Award. The winners are selected based on votes cast by the attendees. We are pleased to recognize the winners from events recently held in Chennai, India and Jakarta, Indonesia.

The winners for the 2012 ARS, India were:

  • Gold - Sivasubramanian Srinivasan of Honeywell Technology Solutions
    Building Reliability in Electronics Design Through Derating Analysis

  • Silver - Pradeep Bhattacharjee of Defence Research & Development Laboratories 
    Structural Reliability Evaluation and Optimization Using Response Surface Method

  • Bronze - Umakant Katu of Whirlpool of India Ltd.
    Effective Use of Combined PoF and QALT for Life Prediction of an Appliance Motor

The winners for the 2012 ARS, Asia Pacific were:

  • Gold - Randolph Phillips of Baker Hughes
    Designing for Life Cycle Costs in the Oil and Gas Services Industry

  • Silver - Erny Cahyaningsih of ConocoPhillips Indonesia
    RCM Implementation in ConocoPhillips Indonesia

  • Bronze - Rony Arsanto of PT. Badak NGL
    Reliability Leading - Lagging Indicator in PT. Badak NGL

The presentation proceedings are now available for purchase at ReliaSoft's Online Store.

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