Reliability HotWire: eMagazine for the Reliability Professional
In this issue:

Issue 18, August 2002

*Hot Topics
*Reliability Basics
*Tool Tips
*Hot News
*Contribute to HotWire

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Hot Topics  
Accelerated Life Testing...Why?
Today's market is fast and furious and timing is everything. What may have taken years to accomplish in the past can now be done in months, or even weeks. If you can release a reliable product before your competitors can release theirs, then you have gained a great advantage. But how can you gain this advantage in time to market? One factor that can play an important role is accelerated life testing. 

Accelerated life testing is still a relatively new subject in reliability engineering, but it is starting to gain greater acceptance in the industry. Accelerated life testing is the process by which a product is forced to fail more quickly than it would have under normal use conditions. Forcing the product to fail more quickly reduces test time and still allows you to understand the life characteristics of the product. Conceptually, this is a wonderful idea, but there are still many concerns. How do I set up an accelerated life test? What are the benefits? How much will it cost and how much time/money will it save me? The answers to these questions are not simple and straightforward, but when is anything worth having easily accomplished?

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Reliability Basics  
The purpose of this section is to offer background and advice to the novice reliability engineer.

Contour Plots and Confidence Bounds on Parameters
There are multiple ways to estimate the confidence bounds of the estimated parameters of a selected distribution. One possible method is the likelihood ratio (LR) method and contour plots. Conceptually, this method is a great deal simpler than that of the Fisher Matrix (FM), although that does not mean that the results are of any less value. In fact, the LR method is often preferred over the FM method in situations where there are smaller sample sizes.

To read more, see 

Tool Tips  

The Tool Tips section addresses helpful hints and frequently asked questions about ReliaSoft software products.

  • What are the differences between ALTA and Weibull++?

  • When conducting a Likelihood Ratio Test in ALTA 6, what does the significance level represent?

  • Using the Function Wizard in ALTA or Weibull++, how can you calculate the results of functions such as R(t=MTBF)?

To read more, see 

Hot News
* Reliability Training Seminars - Next seminar in August in San Diego! The next ReliaSoft "Master the Subject, Master the Tools" seminar will be held in San Diego, California from August 19 - 23, 2002 at the Holiday Inn by the Bay. For more information on course content and how to register, see


Reliability Growth - New RG versions in the works - ReliaSoft is very pleased to announce a cooperative agreement with Dr. Larry Crow for the development of a new Reliability Growth software suite. The software will include the most advanced theoretical models, as developed by Dr. Crow, and will feature his methodology for reliability growth management and planning. Look for more details on this in the months to come.
* Harley Davidson joins the ranks of customers with ReliaSoft Corporate Wide Licensing - Harley Davidson is the most recent company to obtain Corporate Wide Licensing of ReliaSoft's Weibull++ software. Welcome aboard Harley Davidson!


New dates for the Reliability Training Courses at the GM Knowledge Center - We are pleased to announce that once again ReliaSoft will be providing training classes for GM employees at the General Motors Knowledge Center in Warren, Michigan. The courses offered will cover three diverse disciplines of reliability engineering and include life data analysis, accelerated life testing analysis and system reliability, maintainability and availability analysis. For more information, visit the GMU Knowledge Center Web site at or contact ReliaSoft at +1.520.886.0410. Class size is limited. GM suppliers should check with GM for class availability. The remaining 2002 class schedule is as follows:


August 26 - 28, 2002 - Life Data Analysis


August 29, 2002 - Accelerated Life Testing
- October 21 - 23, 2002 - Life Data Analysis
- October 24, 2002 - System Reliability
Contribute to HotWire
Contributions Welcomed
As always, your feedback and contributions are appreciated. ReliaSoft is able to provide the most user-friendly reliability software packages and support because we listen to our customers. This applies to our newsletters and publications as well. We welcome any suggestions or contributions you may have for Reliability HotWire. If you have a topic or article that you think would be useful to the readers of Reliability HotWire, feel free to contact us.

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