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# Reliability Theory - Science topic

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Questions related to Reliability Theory

I wish to know the difference between the BN and Markov model. In what type of problems one is better than other?

In case of reliability analysis of a power plant, where equipment failures are considered, which model should be used and why?

Thank You!

I want to do a research about visual landscape in urban greening and people's preference of landscape,so I need some reliable theories about it to evaluate aesthetics.What's more,I research it with seasonal change,so it is necessary for me to know more about landscape aesthetics quality with seasonal changes. Thanks a lot,if you could help me.

Dear all,

**Does anyone know how can I estimate the NHPP reliability function through Non-parametric method?!**

I know the

**Kernel density estimation**is widely used in this area, but seems it has very complicated theory.I was wondering if you could suggest an example or statistical software directly.

Also, I am just attaching the needed formulas of Kernel model.

Thanks for your attention.

Best/Hamzeh

I am very confused about the formula for availability because it is given by uptime/uptime+downtime.

If f(t) represents the probability density of failure rate, then how it it possible that f(t) will follow exponential distribution whereas the failure rate is constant?

Dear all,

I really appreciate it if someone could reply my question.

The parameters based on NHPP are Shape= 0.46, Scale= 20.54.

and operation time

0, 50, 100, 200, 300, 400,..., 1000

for more detail, please find the attached file.

I do not understand why the reliability values are unreasonable!!

Thanks in advance,

Hamzeh

Hi all,

It is easy to show that the reliability of the MEAN score is the same as that of SUM score but I have not found any article/source of that. If you know such an article/source, please, send a note.

When forming the score of, for example, an attitude scale, we can form it by using either the SUM or MEAN operation. The alpha coefficient of reliability of the scale/score (KR20 or "Cronbach's alpha") uses the variance of the SUMMED scale/score in the formula/calculations and, hence, we cannot use the basic formula when estimating the reliability of a MEAN type of "sum". This is because the variance of the SUM is greater than the variance of MEAN and, if using the variance from MEAN type of "sum", we get faulty (out of range) result by using the classical formula. It's easy to show the reliability estimate is the same in both cases but I have not found a reference for that. Too obvious?

Let's say a system has a backup/standby unit. The failure rate and repair time of each unit are known. How to calculate the equivalent failure rate and repair time? I need these numbers to calculate the SAIDI and SAIFI. Correct me if I'm wrong, but I think those units are not in parallel redudancy since it takes time to switch to the standby unit in case of failure of main unit.

What are the cut-off values for the following reliability coefficients?

Guttman's (1945) Lambda 4 λ4

Bentler and Woodward's (1980) glb

McDonald's (1978) Omega-h ωh

McDonald's (1978) mega-t ωt

I failed to find any threshold for these coefficients.

Hello, I need a very short version of a reliable "Social Desirability Scale" (less than 10 could be ok). I already found the "Brief Social Desirability Scale (BSDS) -5 Ítems-", but found several studies that argue lack of its reliability. Could anyone help me with it?

Thank you

I am trying to perform a simulation using the available reliability techniques in particular the Monte Carlo simulation .I need to predict the reliability of the railway infrastructure system. This system is composed of the Track ,Signalling and Electricals. The available data for all the subsystems is recorded as follows is :

1) Incidences that cause delays

2) MTBF

3) MTTR

How can i approximate failure distributions for failure data given as MTBF /MTTR for a reliability model of a railway network.

A Monte Carlo simulation requires failure distributions which can be approximated by statistical means (Weibull/Lognormal)

How do I choose the correct distribution with the given data (MTBF/MTTR/train delay etc) for

1) Failure rate

2) Repair rate?

I have a scale of 10 items which all test respondents' knowledge on a specific legal issue. The responses could be true, false or unsure. Correct answers are given a score of 1. Incorrect answers and "unsure" answers are given a score of zero. Then the respondent is given a total knowledge score out of a possible 10. I ran a reliability analysis on this scale and resulted in Cronbach Alpha of .65. Can this scale be considered reliable?

Test of reliability and validity is the spirit of research without which research is worthless. But the case of literary studies (i.e., the analysis of fictional writings like drama, novels, poetry, stories) is different from other studies. so.. How can one make the literary research work reliable and valid?

Let's sketch a scenario... when one is dealing with the analysis of stories (written in different years e.g., 1999, 2003, 2007, 2013, 2016) that represent culture of one specific place. Whatever the culture of the place in 1999, is now not the culture of 2007...further 2007 is different from 2016... How we can make our research authentic..original. Researchers often generalize their research studies by amalgamating different literary pieces of different times and different studies. Why?

Is their any criteria to make a literary study reliable and authentic?

Dear all

I am wondering is it right to have a validity index value more than the value of the square root of the reliability index, while there is a rule that

max validity( = or less) sqrt Reliability index

is that rule valid for all method of extracting reliability and validity.

thank you

According to Bohmian quantum mechanics, dependence of quantum potential on all factors and boundary conditions, locally reflects the whole even in the one-particle case. But physicists usually use the term non-locality only in many-particle processes. Unfortunately, physicists usually do not consider the importance of the quantum potential and its dependence on form rather than amplitude in the one-particle case. Bohr was very clear about this non-locality. He did not use that word, he preferred to talk about the wholeness involved in quantum phenomena. What do you think about non-locality?

we will find the liner relationship between reliability and risk in the maintenance, Determination index that show weight tow criteria: risk and reliability

I have 144 EMG traces and the reaction time has been calculated by two different methods. I want to calculate a reliability statistic which will tell me how closely the two methods are related or consistent. Is this inter or intra reliability? Initially I was thinking Pearson's r, but now I think I need an absolute measure of reliability such as SEM. In which case I would calculate IntraClass Correlation, but I’m not sure it is within subject data? Any help would be much appreciated.