Agent Story
There is a large, vast ocean that holds sharks and fish. This model is closely resembles a Predator/Prey model. The sharks are the predators and the fish are the prey. The sharks are attracted to the fish and the fish will attempt to swim away from the sharks. People are then added into the model and they have a determining factor on whether or not the sharks will feed in that area or the fish will swim in that area. There are also fishing boats which will deposit a food source to attract sharks to their location. The sharks will have a certain amount time they can survive until they have reached the age at which they expire. The fish will also have a certain amount of time to live before expiration. Both the sharks and the fish can reproduce but the fish have a faster reproduction rate. The people will not have a reproduction rate or birth rate but instead have some kind arrival rate at which some enter the ocean instead of being born in the ocean. The fishing boats will arrive randomly depending on how many sharks are in the ocean because they are attracted to the sharks because they are to feed them and other carnivorous sea life.
Extra: There will be a pollution factor that will cause less people to go to the ocean and less sharks and fish populating the ocean. There will also be a tide factor which will cause the location of most fish and sharks to be moved.
Agent Model
Agents
- Sharks
- Fish
- People
- Fish Boats
- Hunters
Factors
- Tide Factor
- Pollution Factor
- Trash Factor
Agent Behaviors
- There is a world
- Sharks move randomly on world
- Fish move randomly on world
- People move randomly on world
- Fish Boats move randomly on world
- Sharks are attracted to Fish
- Sharks eat Fish
- Fish swim away from Sharks
- People swim in the ocean and scare fish away from the surrounding area
- Sharks do not go near any people and vice versa
- People leave the ocean after a certain amount of time
- Sharks die after a certain amount of time due to age
- Sharks will die after not eating for a certain amount of time
- Fish will die after a certain amount of time due to age
- Fish Boats will attract Sharks to their location due to them dispersing “food” for the Sharks
- Fish Boats are attracted to Sharks because of their job to feed the Sharks
- Sharks reproduce to make more young
- Fish reproduce to make more young
- Fish have a larger reproduction chance than Sharks
- People have an arrival chance
- Hunters have a chance to become tired depending on the amount of sharks
- Hunters will kill a shark if they are next to one
- Hunters will pick up trash if they are next to one
- Fish will become entangled Fish if they are next to a trash
- Entangled Fish will die after a certain amount of steps
AgentCubes Examples
Challenges with the Agent Model
I ran into multiple challenges for this model. For once, the scent on the fish just wouldn't work and I have to finish the scent for the fish boats and fix the problem with the fish scent. I also had a problem with agents that were made to spawn other agents. For example, when I made the spawner for the agent(fish) which the spawner is called Coral_Reef. It wouldn't spawn them but it would spawn the opposing agent which was the snakes. They were spawning and the people were spawning too, but the fish weren't. I solved the problem by looking at the rules that defined the coral reef and discovered that the rule was never there in the first place. I had much more minor problems such as rules written wrong or an agent disappearing for no reason or never dying for no reason. The scent problem was really the only major problem with the model.
How I pushed the limits of my agent model and what I learned from it
I didn't push the limits of the agent model as much as I wanted it to do. I was able to have the fish move an extra couple of spaces when they are near a person which caused more of the fish to either stay away from sharks or more fish to be devoured by the sharks. This was unexpected for me because when I was in SSP, I added this feature to my agent model for the poachers and rhinos. This feature was added to the rhinos so they could survive longer. In the end, I was extremely satisfied with the end result, even if it was unexpected. The fish actually survived longer than I thought they would. I also learned how another food source could affect a predator/prey relationship drastically. The fish boats fed the sharks and that increased their population and the amount of fish eaten. I wouldn't think that the drop of fish would be so drastic. I also had to add spawner agents to the world so the populations' of all the agents wouldn't simply disappear off of the model.
**Update** I was able to add a significant amount of things to my website. I decided to turn the Hunters into Guardsmen or Lifeguards and allow them to pick up the new factor which I called Trash. The trash is left by people and they can catch fish and turn them into entangled fish which cannot move until a guardsmen/lifeguard comes and saves them, turning them back into a regular fish. I also added the pollution factor which will kill both fish and sharks alike. The pollution is made from the fish boats scouring the ocean. The pollution will also cause the people in the ocean and on the beachfront to leave.
System Model
Variable
- Sharks
- Fish
- People
- Fish Boats
- Hunters
Constants
- Pollution
- Tidal Waves
Relationships/Rates
- Sharks have a direct relationship with the Fish and they eat the Fish at a certain rate.
- Sharks have an indirect relationship towards People and they are never involved with the Sharks unless they are near a feeding ground which is affected by an interaction rate which will give the People and the Sharks interact with each other.
- Sharks have a direct relationship with the Fish Boats because of the Boats feeding them.
- Sharks reproduce young at a certain rate.
- Fish reproduce young at a certain rate.
- The Fish reproduction rate is much more faster than the Sharks reproduction rate
- Sharks will die after reaching a certain point or they will have a chance to die before reaching their expiration point or due to starvation.
- Fish will die after reaching a certain point or they will have a chance to die before reaching their expiration point.
- People arrive at the ocean at a certain rate.
- People leave the ocean no matter what after a certain time period.
- Sharks have a death rate
- Fish have a death rate
- People have an arrival rate
- Fish Boats have an arrival rate which is determined by the amount of sharks
- People have a depart rate
- Fish Boats have a depart rate
- Hunters have a direct relationship with Sharks when killing them off
Vensim Model Examples
Challenges with the System Model
The system model didn't have as many problems as the agent model. The main problem with this model was when I had system problems and the app I was using (Vensim) and it was not doing what I wanted to. It never saved the model and it messed up twice. I started a third time and was successful in finishing it. I had other minor problems such as the values skyrocketing and the slider bars not working whatsoever. The system model was extremely fun to make. I myself find system models much more easier to create than agent models.
How I pushed the limits of my system model and what I learned from it
The system model is where I pushed the limits extremely. I added a completely new agent that I didn't entend on adding to the model. I called the new agent "Hunters" and they were added because of something I hadn't expected. For some weird reason, the sharks population were enlarging by the second and they didn't seem to minimize. I needed to add some sort of killer agent that would allow fish to grow and the amount of people/tourists to grow. I also added a capture relationship between the fish boats and the fish. This caused something I didn't know would even happen. The increase of the capture rate would increase and decrease the amount of sharks at the same time. I figured out that it was caused because sharks grew off of the amount of fish and since they were getting captured but they were also getting fed by the fish boats.