NetLogo User Community Models
Growing peppers greenhouse
by J.P.M. van Ruijven (Submitted: 12/13/2009)
WHAT IS IT?
This model is built to show a greenhouse owner the amount of employees it needs to get the best result in harvesting peppers. More harvesters means more peppers are harvested, but also mean more costs. The goal of this model is to find the optimal amount of employees. Economics are not included in the model, but can be insterted when handling the results of a behaviour space.
HOW IT WORKS
Harvesters start walking through the greenhouse in straigth paths. Every step they take they check wether the patch they are on is green, red or white. If the patch is green, nothing will happen and the harvester will walk further. If the patch is red, the harvester will harvest the pepper and take it with him. The patch will now turn green again. If the patch is white, also nothing will happen and the harvester will walk further. Green means: on this patch is no pepper ready to be harvested. Red means: on this patch a pepper is ready to be harvested. White means: on this patch are no more peppers.
HOW TO USE IT
The SETUP button creates a greenhouse with not fullgrown plants in it and on the top line a number of employees is situated, determined by the number-of-harvesters button.
The GO button makes the plants grow and produce red peppers. The employees start harvesting the red peppers and collect them till they have collected 10 red peppers. The employees turn the red fields green again. When 10 peppers are collected, the employee jumps back to a random place in the top line of the field and the counter turns zero. The RED-CRATES counter adds one to the total amount.
The number-of-countdown slider determines the amount of peppers growing on a patch. If a pepper is harvested this patch-own goes down by 1. If this number becomes 0, the employee makes the patch white.
If there are not enough employees to harvest the peppers, some of them will rot. This happens when the pepper is red for a certain amount of time. This time can be set with the number-of-rot-time button.
THINGS TO NOTICE
Notice that when a small amount of employees is used, the number of crates at the end is far lower than when a lot of employees is used. How is this possible?
THINGS TO TRY
Try to vary the amount of harvesters and see the difference in the amount of peppers harvested.
EXTENDING THE MODEL
In the procedures tab some things can be adjusted. For example the amount of peppers that turn red every tick is now stated randomly as 1-4%. Also the speed of the turtles can be adjusted. Some things to extend the model are for example a variable speed of the employees. If there are less peppers, the employees can move faster. Another thing is a variable amount of employees.
A workaround was necessary where the employees needed to jump to the first line in the model. A new employee is now created on a random place at the top line and the old one dies when 10 peppers are harvested.
The rabbits-grass-weeds model uses the same idea of agents running around and then changing the patches.
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