Inter Arrival Pattern

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Chao Gao asked Mar 21, '17 Ben Wilson edited Mar 21, '17

Inter Arrival Pattern

interarrival-sample.txtI am trying to use flexsim to generate arrive patterns showed in the attached file, for every 10 minutes during a day, i am having a total quantity of units arrived during that time period, and within that 10 minutes, I just need uniform distribution, existing selection"Periodic rates" only has hourly period defined, is there an easy way to model this pattern? Thanks!

Software Version:

FlexSim 17.0.3

interarrival

interarrival-sample.txt (5.2 KiB)

Answer 1 · 2017-03-21T10:21:39Z

Raja Sekaran answered Mar 21, '17 Raja Sekaran edited Mar 21, '17

Hi Chao ,

I built a simple model the way you wanted but using process flow and attached it here.

In source activity, I have assign a label value(ArrivalNo) for each row.

Then assign a label Name (Interval) for each token.

Then get the value of Arrival quantity based on ArrivalNo.

In delay activity, delay time = Interval/Arrival quantity use this formula to hold the token certain length of time. Then you can create object based on token release.

I hope this will help you.

inter-arrival-pattern-1.fsm

arrivalno.png (14.1 KiB)

interval.png (2.5 KiB)

arrivaltable.png (10.7 KiB)

inter-arrival-pattern-1.fsm (19.6 KiB)

Answer 2 · 2017-03-21T14:11:26Z

Ben Wilson answered Mar 21, '17 Ben Wilson edited Mar 21, '17

Please find attached a version that uses the 3D objects+triggers, rather than process flow. Not saying this is better or worse than process flow, just a different approach that may fit better into certain existing models.

In the attached model, the Global Table "arrival schedule" + the Queue + the Processor = a Source.

Global Table

I imported your data, but first used Excel to convert the times to military time (00:00:00-23:59:59) for ease in translation to whatever your model time units might be. Also broke the hours, minutes, seconds, into their own columns, again for ease of time conversions.

The Queue

Added a reset trigger that sends itself a message at the time of the first arrival. This is how we kick off the schedule. This assumes your model starts at time 00:00:00. If you have a different start time, modify accordingly.

The message trigger handles creating the flowitems and giving each one a unique arrival time across the desired interval. The logic included in this sample model hard-codes the uniform distribution, but you could modify to handle other distributions based on your arrival schedule. Finally, the message trigger ends by scheduling the next arrival event with a delayed message.

Model time is assumed to be seconds, so code will need modification for other time units. This is for example purposes only.

The Processor

This is how we spread the arrivals across the duration specified in the arrival schedule. The processor acts as a delay for each flowitem, allowing each to arrive in the model (out the processor) according to the desired distribution across the duration.

multiplearrivalspertablerow.fsm

multiplearrivalspertablerow.fsm (17.7 KiB)

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