Bee Vibration
Moods Median Test
Mood’s Median Test

This nonparametric hypothesis test tests the equality of population medians. While not as powerful as the Kruskal-Wallis Test, it is useful for smaller sample sizes, when there are a few outliers or errors in the data as it focuses only on the median value.

One assumption to check concerns the similarity or equality of the underlying variances (or shapes) of the different…

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Data to collect to optimize maintenance

Data to collect to optimize maintenance

Information for Maintenance Planning

One of the considerations when planning maintenance is the timing of replacement of parts of the system. In some cases it makes sense to wait for the item to fail, sometimes, it makes sense to replace on a interval or set amount of operating time, and yet in others we can measure indicators that a replacement is necessary.
I order to make these decisions we…

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Expectation and Moment Generating Functions

Expectation and Moment Generating Functions

Expectation and Moment Generating Functions

In statistics and reliability we use distributions to describe time to failure patterns. The four functions commonly used in reliability engineering include

  • The probability density function
  • The cumulative distribution function
  • The reliability function
  • The hazard function

We often use terms like, mean, variance, skewness, and kurtosis to describe…

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at Mountain Winery Concerts

at Mountain Winery Concerts

Benefits of Reliability Engineering

Benefits of Reliability Engineering

Benefits of Reliability Engineering

We see the terms ‘reliable’ and ‘reliability’ in daily advertising, business names and in casual conversations on a regular basis. Reliability has meaning and importance in our society. Product and brand reputations are made or broken by their product reliability performance.

Reliability engineering or the work to minimize failures, improve maintenance…

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Censored Data and CDF Plotting Points

Censored Data and CDF Plotting Points

2008-04-30 RockClimbing
Censored Data and CDF Plotting Points

Reliability testing and data collection is messy business. We rarely receive perfect data where all units involved have a precise time to failure record. Sometimes we do not precise time to failure information or some of the units are still operating.

The data is censored. There are a few common types of censoring each of which have statistical techniques to…

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4 Electronics Nondestructive Evaluations

4 Electronics Nondestructive Evaluations

2008-04-18 RockClimbing
4 Electronic Nondestructive Evaluations

It is possible to use the circuit design or the circuit itself to evaluate electronics. This ranges from checking is the system is wired correctly (the right parts are present and attached properly) to a complex evaluation including the proper functioning of firmware and attached software.

Beyond visual inspection, we need a way to evaluate the microscopic…

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8 Nondestructive Evaluation Techniques

8 Nondestructive Evaluation Techniques

2008-04-21 RockClimbing (3)
8 Nondestructive Evaluation Techniques

There are times when we need to evaluate a product to determine is it assembled correctly or when looking for clues concerning a failure mechanism. Simple visual inspection may be sufficient and there are times when we need more information or detail.

A great first step is the use of an appropriate nondestructive evaluation (NDE) method. Done correctly we…

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8 Factor of Design for Maintainability

8 Factor of Design for Maintainability

2009-06-02 RockClimbing (2)
8 factors of design for maintainability

The first time I changed the oil filter of my car (first car in high school) I smashed my knuckles against an grimy block of metal. More than once. It may have been my lack of experience or improper tools. Or, it may have been a rather poor design

Watching the Indy 500, especially the pit stops, I quickly realized there has to be something different about…

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Reliability Testing Considerations
Considerations for Reliability Testing

Reliability testing to determine what will fail or when will failures occur is expensive. Organizations invest in the development of a product and attempt through the design process to create a product that is reliable.

The design process has many unknowns though. This includes uncertainties about materials, design margins, use environments, loads, and aging…

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