Accumulated Idle Time in Simulation

Without knowing exactly what you've set in your models it's hard to identify the cause of the problem you are seeing. My guess would be that the shift for the organizational unit is not set correctly.

I've attached a database with a very simple sample. (It's zipped so that the community software would let me upload it.) It contains an EPC with one function that is excuted by an organizational unit. The function has a processing time of one hour. The organizational unit has a schedule assigned with a calendar event that specifies a working time of two hours per day. When you simulate the EPC for a few days, the utilization of the organizational unit should be shown as 0.5 and the accumulated idle time should be as high as the accumulated processing time.

Before you try this, you should make sure that you have the latest version of ARIS 7.2 installed.

Thanks a lot, Ralf. I'll try this and post the results here.

I've run the simulation step-to-step and noted that every time the function is run, only 10 minutes are added to "Busy Time" and 9 hours and 50 minutes to "Idle Time", which is equivalent to 1 doctor working and the other 4 idle. If I set Processing Time to 50, Dynamic Wait Time shoots. I'm attaching a simplified version I'm using to debug.

I'm using a 2 hours shift calendar which assigned to both the start event and the role.

Another problem I encountered is assigning frequency to start event. If I assign a frequency of 50 to start even, it doesn't run according to the shift assigned but, instead, runs a 24-hour cycle and produces 50 runs. This, too, creates a lot of waiting processes for function assigned to the role, which is only available according to the shift. Assigning the same frequency to subsequent event doesn't create the exact number of tokens for the doctor to process.

It's not a good idea to assign the same shift calendar to the start event and to the role. Calendar events in a schedule model are either process instantiators or specifiers for working times, not both. So it's better to use two separate schedule models: one for process instantiation at the start event which includes only process instantiators and one with calendar event which specify working times for the role.

Note also that a schedule at a start event cannot be used to specify something like a shift. As mentioned above it's only used for process instantiation. The simulation will always run for 24 hours per day.

Regarding the frequency: In your screenshot it looks like a frequency is set at the event "ticket cretaed" (sic!). This won't have an effect. The frequency attributes are only relevant for start events. Also, if a schedule is assigned to a start event, this will overrule any frequency attribute.

In your screenshot it also looks like you set the attribute "Number of employees" at the connection between the role and the function. On the connection the attribute is ignored by simulation. It only has an effect if it is set directly at the role. When looking for simulation attributes in ARIS 7.2 you should look into the group "Business Simulator attributes", not in the group "Simulation" which has been used by ARIS 6 and earlier.

Thanks, Ralf. Your comments were immensely helpful! :)I had tried using two different calendars too, but couldn't sort this issue. And yes, I had assigned the "Number of employees" to the role, too, but didn't know why it wouldn't work!! This time, I changed the instantiations attribute of Process instantiation (a different calendar, though), and Voila!! working like a charm! :) Even the simulation is running for the two hours of the shift.

Thank you so much for the help!

Problem again! How do I control generation of tokens for the weekend? I've noticed "Number of process instances" and "Days of week of recurrence" attributes can't be used simultaneously. I guess the former is for work shifts, and latter only for start events. In my simulation, the assigned roles don't process anything on weekend but start event keeps generating tokens, creating a backlog for the roles.

Thanks!

You can make process instantiators with a weekly recurrence. If you only want process instances generated on weekdays, you can make five instantiators for the days from Monday to Friday.

Note that you should edit process instantiators with the context menu entry "Process instantiation..." of a calendar event.

Thanks Ralf, but I see no option of assigning weekdays by using"Processes instantiation.." I've tried using both Edit->Process Instantiation.. and Edit->Date and Time..  to all the Calendar events but to no avail. In the attached screeenshot, Mon-Wed are modeled using "Process instantiation.." and Thu-Fri using "Date and Time" entry. Can you please suggest what's the right way? The schedule for all weekdays is essentially the same: about 57 tokens and 2 hours duration.

P.S. I have 3 start events XOR-ed in the EPC, and only one is assigned a schedule. The other two have frequencies which are negligible compared to the first event.

Thanks!

If the start date of a process instantiator is on a certain weekday and the instantiator has a weekly recurrence, then it will always recur on the same weekday.

Thanks! The problem was I had assigned the same starting dates to almost all the Calendar Events.