Assignment
1. Create rine model using FlexSim
2. Study the effects of two factors (see barameters.xls) by experimenting with different values of the relevant parameters
3. Write a report (see report.pdf) where you present the results, discuss them and make conclusions
Studied factors
Line length (basic length = 4 stations)
Buffer size (basic size =2 places)
Processing time variation (basic values: Erlang = 1/10, K = 5 => average = 10, standard deviation = 4.47 = average/NX = 10/-45; )
Utilisation rate (basic value = 100 %). See note at the end of this instruction.
Observed and analysed results
Output
Throughput time
Output variation between simulation runs
Throughput time variation (of individual products)
USING PARAMETERS
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Line length
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Buffer size
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Processing time variation
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Utilisation rate
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x
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x
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4,47
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100%
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x = parameter to be varied in testing
Assignment
Things to consider
Run length, warm-up period length
Number of repetitions with each parameter value combination
Use CV (coefficient of variation = standard deviation 1 mean) to study variation of throughput times
How do I set the utilization rate?
If utilization rate is not your adjusted parameter, set interarrival time so low, that jobs are always available at the beginning of the line_ In this case the line Is always fully loaded and the output Is limited by the line itself.
If utilization rate is your adjusted parameter, you change it by adjusting the negative exponential distribution average at the source. You can show directly the average in your results and/or 'nominal" utilization rate so that 10 minutes average (= processing rate) corresponds to 100 %, 12 minutes to 10/12 = 83 %, 14 min to 71 % and 16 min to 63°10 Going much lower than that is not relevant, as you can conclude from the results.