Telephone System Reliability Testing via Orthogonal Arrays and Field Data
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Solution Overview
Problem
Existing reliability testing methods for software-controlled telephone systems, such as those using the Taguchi method and orthogonal arrays, fail to effectively identify mean-time-to-failure due to arbitrary selection of test parameters and inability to mimic realistic system usage across varying environments, leading to inefficient and unreliable results.
Innovation Solution
The integration of orthogonal arrays with field data to generate test parameters that reflect realistic operational profiles, allowing for the computation of mean-time-to-failure and other reliability statistics by scheduling testing matrices according to actual usage patterns, enabling efficient, repeatable, and remotely executable reliability tests.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If orthogonal arrays are used for testing, then the number of test parameter combinations is reduced, but the test parameters become arbitrary and do not reflect realistic system usage
Solution Approach 1:
The patent transforms the test parameter selection from arbitrary orthogonal array values to field-observed realistic values. By changing how parameters are selected (from random orthogonal values to actual field data values), the test maintains the efficiency of orthogonal arrays while achieving realistic system usage representation.
Solution Approach 2:
The patent copies actual field operational data to create test parameters. Instead of generating synthetic test data, it replicates real-world usage patterns observed in field environments, ensuring that the test scenarios accurately reflect how the system is actually used.
2Adaptability or versatility
If random test generation is used, then test coverage is broad, but the tests do not converge to mean-time-to-failure with a given confidence factor
Solution Approach 1:
The patent uses field data as feedback to guide test parameter selection. By analyzing actual operational data from the field and using it to inform test generation, the system achieves both broad coverage and statistically valid reliability metrics that converge to mean-time-to-failure.
3Loss of time
If exhaustive system tests are replaced by orthogonal array techniques, then testing time is reduced, but the tests cannot provide acceptable solutions for systems with too many possible states
Solution Approach 1:
The patent makes the orthogonal array dynamic by generating different arrays for different environmental conditions. Instead of using a single static orthogonal array, it adapts the array generation to match specific operational environments, allowing the same methodology to handle systems with many states across varying conditions.
Data Source
AI summary
A method for generating reliability tests for a telephone system is based upon sampling an orthogonal array which covers various combinations of test parameters. Field data is collected of actual telephone activity on a telephone system. The field data is evaluated so as to determine call-mix characteristics. Probabilistic weights for the different call-mix characteristics are obtained, and then the probabilistic weights are used to sample the test case scenarios generated in the orthogonal array which have the same call-mix characteristics. These test case scenarios are used to run tests on the telephone system. These tests are preferably performed using automated test scripts. After the test data is collected, reliability metrics are calculated from the test data.