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It has
been said that a software package capable of
analyzing accelerated life data from tests conducted
using time-varying stresses is widely needed and
that the development of such a package would be a
major undertaking, requiring a team of engineers,
statisticians and programmers.
It
is, it was and...
ReliaSoft did it!
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The first, and still the only,
commercially available software package designed expressly for
quantitative accelerated life testing data analysis, ReliaSoft's
ALTA software provides an
intuitive and user-friendly way to utilize tremendously complex
and powerful mathematical models. The software provides the
life-stress relationships required to analyze accelerated life
test data with up to 8 simultaneous stress types where stress is
constant or varies with time!
When you apply
quantitative accelerated life data analysis principles and use
the ALTA software for analysis, you can significantly
reduce test times, resulting in
faster time to market, lower
product development costs,
lower warranty costs and other benefits.
Quantitative Accelerated Life Testing (QALT)
In quantitative accelerated life testing (QALT), the stresses
that cause product failure are accelerated under controlled
conditions to cause the product to fail in a shorter period of
time without introducing additional failure mechanisms that
would not occur under normal use conditions. Unlike qualitative
accelerated tests (such as HALT/HAST), which precipitate
failures in order to identify failure modes, QALT produces
time-to-failure information that can be used to estimate the
expected life of the product under normal use conditions.
When such tests are performed
correctly, you can use mathematical models to extrapolate a
use-level cumulative distribution function (cdf) for the
product from the life data obtained under accelerated
conditions. You can use this analysis to determine reliability,
probability of failure, warranty time, mean life, B(X) life and
other information about the expected life of the product.
ReliaSoft’s ALTA Software
ReliaSoft’s ALTA software
provides full support for analysis of data obtained from
quantitative accelerated life tests. The software is available
in two versions: Standard and PRO.
The
Standard edition is intended
as an entry-level tool for the reliability professional
interested in basic quantitative accelerated life testing data
analysis applications.
ALTA 7 PRO provides advanced
capabilities made possible by extensive research and development
in complex quantitative accelerated life testing data analysis
techniques.
[See Comparison]

Features
include:
- Data Types: ALTA's
data entry spreadsheets support Complete, Right Censored
(Suspended) and, new in Version 7,
Interval or Left Censored data, entered individually and in
groups, with up to eight stress types (depending on the
life-stress model). In addition, the Monte Carlo utility
provides randomly generated data sets based on a specified
model, distribution and parameters.
- Distributions and
Life-Stress Relationships: ALTA supports data analysis
with the Weibull, lognormal and exponential distributions
combined with the following life-stress relationships:
Arrhenius, Eyring, Inverse Power Law, Temperature-Humidity
and Temperature-NonThermal.
ALTA PRO supports additional multi-stress and
time-varying stress models, including Proportional Hazards,
General Log-Linear (with user-defined transformations),
Cumulative Damage and,
new in Version 7, Generalized
Eyring.
- Time-Varying Stress
Profiles:
In ALTA PRO, you can define stress profiles that vary with
time, such as step-stress, ramp-stress, etc.
Enhanced in version 7, the Cumulative Damage model
now supports analysis of multiple time-varying stresses!
- Parameter Estimation
and Calculated Results: ALTA uses Maximum Likelihood
Estimation (MLE) for parameter estimation. The QCP and
Function Wizard quickly return calculated reliability
results (such as reliability given time, mean life,
acceleration factor, BX life, etc.) based on the data
analysis and your inputs. Confidence bounds are available
for all calculated results and parameters.
- Unparalleled Plotting
Capabilities:
ALTA automatically generates a complete array of
reliability plots, with customizable plot settings. This
includes Probability, Reliability vs. Time, pdf, Life vs.
Stress, Acceleration Factor vs. Stress, etc. Plots are
metafile graphics (*.wmf) that can be annotated and used in
your reports and presentations.
- Accelerated Test
Planning Utility: New in Version 7,
this utility implements the complex mathematical models
required to design an effective accelerated life testing
plan, which accounts for the type of stress, method of
applying stress, stress levels, number of units to be tested
at each stress level and an applicable life-stress model.

- Utilities for Related
Analyses:
Degradation Analysis, Tests of Comparison, Likelihood
Ratio Analysis and flexible spreadsheets for your own custom
analyses.
- Integration with
Weibull++ and Other Software: Now
in version 7, ReliaSoft's
ALTA 7
and Weibull++ 7
are now more closely linked than ever before. Now a single
project file (*.rs07) can contain both ALTA and Weibull++
analysis folios and you can easily switch back and forth
between the two products with the click of a button! It's
now easier than ever to transfer data from ALTA to Weibull++
for additional analysis, keep your Weibull++ analysis of
field data together with the original QALT estimates, and
much more. ReliaSoft also makes it easy to access ALTA
analysis results from within
BlockSim,
RENO,
Xfmea and
RCM++.
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