NetLogo User Community Models

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## WHAT IS IT?

The model tries to illustrate the problem of maintaining common pool resources in a society with peoples of different attitudes towards the social benefit from serving comon interest. In this frame the model introduces social persons and opportunistic free riders into the world which are all focusing one common good of limited number and limited operation level, the bicycles.

## HOW IT WORKS

The agents of different breeds (social persons and freeriders) are setup in an environment (grid), which contains ground, introduced by patches with the attributive operation-level of -1 and grey color, operating bicycles, set as patches with operation-level of 20 and green color and broken bicycles with operation level underneath 5 and of brown color. The breeds are distinguished through the different value of the state variable attributes, which is willingness-to-repair, their attitude. According to their attitude, the breed react differently on the state of the patch there are on and also the state of the patch (operation level) changes due to interaction with agents. All agents are moving equally, if patches are grey. Nobodies state will change. If any agent reaches a green patch, which assumes an operating bicycle on it, it will follow subcommand of drive. This behavior influences social persons breed attributes, who gain willingness-to-repair through driving (benefiting) while the affected patches loosing operation-level and might turn brown (broken) if operation level is below 5. If it is a social person whose willingness-to-repair is above zero they will conduct the subcommands of repair and update the operation-level of the brown patches (broken bicycle). If their willingness is lower, they going to react as the free riders by walking off checking others when the reach broken bicycles.

## HOW TO USE IT

Start with setting up the environmental grid, which contains 10 % operating bicycle and a numer of social persons and freeriders shaped as persons with different colors.
Set two initial values of benefit-from-driving (= increase of willingness-to-repair through driving) which is one of major attribute, representing the ability of social persons to maintain common pool resource for communal use. High values will end of in exeggerated values of willingness-to -repair, try to adjust on lower numbers, since differences in values below 10 cause sensitive impact on stability of the system. Adjust also number of freeriders to see, at which level of number of freeriders the number of operating bikes will reach zero. Press "go" button to start the proceeding and watch the plots to check the emerging aggregated numbers and values.

## THINGS TO NOTICE

You might expect, that the number of freeriders, who are just (ab-)using the benificial part of the common pool resource, driving, might influence the outcome of maintenance and therefore the number of operating bicycle. The models shows that this assumption is wrong. While the number of opportunistic freeriders is only slightly affecting the number of operating bicycles the actual impact is done by the benefit and social agent receives from driving, using the common good.

## THINGS TO TRY

see chapter >HOW TO USE IT<. The user is free to create further slider on his/her own. There is room to add for example "loss-operation-level-through-riding" as quality-feature through attaching it in the interface and in the code inside the drive-subcommand. Other similar dynamic adjustment can be done through the introduction of variable effort-to-repair, which could be introduced as slider into repair-subcommand.

(suggested things for the user to try to do (move sliders, switches, etc.) with the model)

## EXTENDING THE MODEL

see chapter >THINGS TO TRY<. Further adaption can me done by more advanced users in adding more breeds to agentset. Like policemen, checking operation-level of bicycles and "confiscating" all with a level below "security-limit". One can adjust level of repairing through random operation-level, assuming social people with different knowledge about proper technical maintenance of bicycles. Or one might open up possibility of freeriders of beeing able to "enjoy" riding through receiving also willingness-to-repair and to switch into breed of social-persons after reaching certain value. If the fantasy stil did not reach its limits, the user might think about introducing cars as final state of a disappointed agent. There is much to try in order to create a more realistic picture of usage of common pool resources in an multifaceted society.

## NETLOGO FEATURES

(interesting or unusual features of NetLogo that the model uses, particularly in the Code tab; or where workarounds were needed for missing features)

## RELATED MODELS

(models in the NetLogo Models Library and elsewhere which are of related interest)

## CREDITS AND REFERENCES

(a reference to the model's URL on the web if it has one, as well as any other necessary credits, citations, and links)