Queuing in PD

[ie_1989]

Hi Marlies
With refer to my previous posts, I am completing a simulation model of a subway station. The station has 2 trains and 2 platforms working with the same conditions(My main focus is on the lower part of the model where the train No.1 is located). The trains have the issue of availability. My problem is that some of the passengers aiming to get on the train (Blue and Yellow agents) don't consider this issue and exit the subway by means of the train when it is not available. As you know I had the same issue with the passengers aiming to leave the train, and by your trick I solved that problem.
I have attached the file named "Metro4". If the problem is solved for the lower side, the upper one will be straightforward. I really appreciate your useful and quick helps.

[marlies]

Hi,

I am glad to help, but can't find the attachment .

Regards, Marlies

[ie_1989]

I am really Sorry... My internet connection got some major problems... Now I have attached it.

[ie_1989]

Hi Marlies
I have attached the file "Metro4"
Thanks for your help in advance

[marlies]

Hi,

What could be the problem is the following:
- When the platform switches to available it executes the following code: {Send all approaching agents to this final activity}
- Also agents that come from the entries 1&3 will be triggered.
- The agent will be sent to the final activity and enter the train, even when (in the meantime) the availability will switch again. To check if the train already left, we would have to add additional triggers.

However, what I see happening in your model is that agents walk to their original destination in the waiting area and then continue walking to their goal location in the train. Because both locations are random locations, the walking distances get too long to get into the train in time.

To solve this you could add an action area before the agents enter the platform. Action areas can be found in Areas and then the button with the footsteps. In the action area's entry trigger choose the default option: Start Agent/Re-plan route. This will make them reroute to the train destination directly and as a result, will be in time.

See also attached model where I implemented this solution.

Regards,

Marlies

[ie_1989]

Hi Marlies, Thank you for your reply
Should I add the action area between waiting area and platform? or remove the waiting area before adding it ?

[ie_1989]

I added 2 action areas near to the entering/exit area to your file. As you mentioned, the chosen route by some of the agents becomes too long in some cases. Therefore the problem exists but with less intensity... Is there a way to force the agents to choose the nearest possible point of the entry/exit area to exit? So they won't have to follow a long path unnecessarily (I have also attached the file having more action areas)

[marlies]

Hi,

There are two ways to do that:
- Write script in the codebox of the location approaching (tab location) that includes the agents current location. The current x and y coordinates of the agent can be retrieved using:

Code: Select all

xabsloc(i, Model)

and

Code: Select all

yabsloc(i, Model)

.
- Another option is to split the train entry/exit into multiple enty/exits (modelling the compartments) and then assigning them to the closest via the default location distribution LeastEffort in the Agent Input > Activities.

Regards, Marlies

[ie_1989]

Thank you so much Marlies
I couldn't understand exactly the first way you mentioned for my problem. How can I use "xabsloc(i, Model)" or " yabsloc(i, Model)" in the script box of the Location Approaching? Should I use them in another function?
I also ran into trouble with my model. In the model the Agents get stuck in some locations without any obstacles. I can't figure it out why this happens
I have attached my model. Please help me with this issue
Thanks a lot

[marlies]

Hi,

I guess you are referring to the fact that agents get stuck in a semi-circle especially close to the gateways. This happened because of a problem in the ECM network. The best way to avoid these problems is to model the obstacles in straight and tidy lines, also when overlapping each other.

For example the network in the lower right part of the model looks like:

example1.JPG (78.99 KiB) Viewed 20117 times

. In the red marked areas some walkable space is missing. When walkable space is missing there is a potential problem. In this case you could choose to:
- Draw the overlap of the obstacles in this position in more exact way.
- Deselect the option "block sides"on the passageways and instead increase the wall width of the obstacle below. This will also simplify the network.

See also attached model where I implemented the 2nd option for the passageways.

FYI: the next version of the software can handle this way of drawing, until that version is released it is sometimes necessary to add corrections like the ones in this model..

Regards, Marlies