Reliability HotWire: eMagazine for the Reliability Professional
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Issue 59, January 2006

*Hot Topics
*Reliability Basics
*Tool Tips
*Latest Software Updates
*Hot News
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Hot Topics

Analysis of Non-Homogeneous Warranty Data

When performing reliability analysis on warranty returns data, it is important to differentiate between cases where the data can be considered to be homogeneous and cases where the data are non-homogeneous. In the case of homogeneous data, all sold and returned units are considered to be exactly the same, i.e. the same population with no design changes and/or modifications. In many situations, however, the units being sold might not all be considered the same due to differences in design, material, etc. For example, many times design changes are made to enhance and/or improve the reliability of the product as the product matures.

In this article, we will explore how non-homogeneous warranty data can be analyzed and how predictions can be made from such data. To analyze such cases, one needs to extract each homogeneous group, fit a life model to each group and then project the expected returns for each group based on the number of units at risk for each specific group.

To read more, see 

Reliability Basics

Parametric Recurrent Event Data Analysis and the GRP Model

Issue 57 introduced the concept of recurrent event data and presented a non-parametric approach to analyze such data. Weibull++ 7 also offers a parametric approach that is performed using the Parametric RDA Specialized Folio. This type of folio can capture the trend, estimate the rate and predict the total number of recurrences. The failure and repair data of a repairable system can be treated as one type of recurrent event data. Past and current repairs may affect the future failure process. For most recurrent events, time (distance, cycles, etc.) is a key factor. With the time, the recurrence rate may keep constant, increase or decrease. For other recurrent events, not only the time, but also the number of events can affect the recurrence process, e.g. the debugging process in software development.


The parametric analysis approach utilizes the General Renewal Process (GRP) model. In this model, the repair time is assumed to be negligible so that the processes can be viewed as point processes. This model provides a way to describe the rate of occurrence of events over time such as in the case of data obtained from a repairable system. This model is particularly useful in modeling the failure behavior of a specific system and understanding the effects of the repairs on the age of that system.

To read more, see 

Tool Tips
  • Can a Weibull++ 7 Warranty Analysis Folio be converted to a different data format?

  • Can values in a RENO Spreadsheet be used during Flowchart simulation?

To read more, see 

Latest Software Updates
New service releases are now available for Weibull++ (SR 7.0.6), BlockSim (Version 6.5.1), RGA (Version 6.5.1), Xfmea Standard (SR 3.0.5), Xfmea Enterprise (SR 3.0.3) and RCM++ (SR 3.0.5). To determine the compile revision of the application on your computer, select About from the Help menu. More Software Downloads...


Application Date Created Version
Weibull++ 7    
Weibull++ 7 12/16/05 7.0.6
Weibull++ 7 Update N/A SR 7.0.6
BlockSim 12/16/05 6.5.1
BlockSim Update N/A Version 6.5.1 is a FREE Version UPDATE to BlockSim.
RGA 12/16/05 6.5.1
RGA Update N/A Version 6.5.1 is a FREE Version UPDATE to RGA.
Xfmea Standard 12/13/05 3.0.5
Xfmea Standard Update N/A SR 3.0.5
Xfmea Enterprise 12/19/05 3.0.3
Xfmea Enterprise Update N/A SR 3.0.3
RCM++ 12/13/05 3.0.5
RCM++ Update N/A SR 3.0.5
Hot News
* New Online Web Store - ReliaSoft is proud to announce its newly enhanced online Web store. Due to popular demand, customers in the USA and abroad now have the ability to use our online "ReliaSoft Web Store" to place an order automatically, obtain a pro-forma invoice or even get a product quotation. ReliaSoft has also added a new eDelivery feature that allows the customer to download a "product pack" instead of ordering a retail shrink-wrap package. The eDelivery product consists of a self extracting *.zip file that includes all of the installation files and detailed resource documentation needed to install and operate the software. The primary benefits of eDelivery include instant delivery and customer savings: ReliaSoft offers eDelivered products at a reduced price, there are no shipping fees and there may be no customs charges for eligible countries. Additional ordering information can be obtained at:
* Improved Software/Training Bundle Options - ReliaSoft has long been the leader in creating exceptional reliability software products as well as providing the training to put the software to use. ReliaSoft USA has now expanded on existing software and training bundling options, providing some of the world's top reliability tools with the most comprehensive training you can find in the market today, wrapped up in one simple discounted package. More than ever before, the combination of tools and training is essential to a focused approach in today's highly competitive environment. Learn more about the various options at:
* Applied Reliability Symposium, Orlando 2006 - Please mark your calendars and begin thinking about attending the 2006 Applied Reliability Symposium ( this June 14 - 16 in Orlando, FL. The Symposium has been booked for the Sheraton World Resort, which is within walking distance of Sea World and 5 minutes away from Walt Disney World and Universal Studios. Registrations are currently being accepted at
Public Training Event Calendar
February 2006
February 23 - 24, 2006: RS 470 - FMEA/FMECA and Xfmea  in Singapore
February 27 - March 3, 2006: MSMT Foundations in Tucson, Arizona
March 2006
March 1 - 2, 2006: Applied Reliability for the Semiconductor Industry in Malaysia
March 20 - 24, 2006: MSMT Foundations in Philippines
March 27 - 28, 2006: RS 480 - Introduction to RCM Principles and Applications in Tucson, Arizona
March 27 - 29, 2006: RS 522 - Advanced System Analysis and BlockSim in Tucson, Arizona
March 30 - 31, 2006: RS 470 - FMEA/FMECA and Xfmea in Tucson, Arizona
April 2006
April 3 - 7, 2006: MSMT Foundations in Cologne, Germany
April 5 - 7, 2006: RS 525 - Advanced Probabilistic and Risk Decision Analysis and RENO in Tucson, Arizona
April 24 - 28, 2006: MSMT Foundations in Tucson, Arizona
April 24 - 28, 2006: MSMT Foundations in Taipei, Taiwan
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