Can the Vensim PLE version achieve seasonal forecasting?

[Xuanao Zhou]

My model's objective is to set safety stock based on the prediction of the next transportation time. Transportation time is influenced by multiple factors and exhibits seasonal patterns; it is longer in the summer and winter seasons and shorter in the spring and autumn seasons. Therefore, I hope to embed a seasonal forecasting module (using the Holt-Winters method) into the model. This module will use historical transportation time data to predict the next transportation time.

Additionally, in the variables I have set for statistical analysis of transportation time, there are instances with a value of 0, indicating no transportation tasks. In such cases, how should I select non-zero data for forecasting?

I have attempted first-order exponential smoothing, but I am uncertain if this approach is reasonable. My basic model is attached for reference.

Looking forward to your insights.

Best, Xuanao

[Administrator]

Start by adding units to your model. I would not bother simulating or doing anything else until your model passes this basic quality check. I can immediately see a problem (you've got a variable called month).

[tomfid]

I think the month variable is intentional, for creating a seasonal input.

Since the seasonal behavior has 3 episodes, switched in an IF THEN ELSE statement, I think you could create the same thing for seasonal smoothing - have 3 smoothing structures, one active during each episode.