CS620 Final Term Modules 126-160

Cs620 final term topic 126 to 160

BS Computer science (Virtual University of Pakistan)

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Cs620 final term topic 126 to 160

BS Computer science (Virtual University of Pakistan)

Scan to open on Studocu

Studocu is not sponsored or endorsed by any college or university

Cs620 final term · Collections of Agents · Types of Agents

Agents are typically divided into three main types:

mobile agents that can move about the landscape;

stationary agents that cannot move at all; and

connecting agents that link two or more other agents.

NetLogo

In NetLogo, turtles are mobile agents, patches are stationary agents, and links are connecting agents. From a geometric standpoint, turtles are generally treated as shapeless area-less points, although they may be visualized with various shapes and sizes). Thus, even if a turtle appears to be large enough to be on several patches at the same time, it is only contained by the patch at the turtle ’ s center (given by XCOR and YCOR). Patches are sometimes used to represent a passive environment and are acted upon by the mobile agents; other times, they can take actions and perform operations.

Patches and Turtles

A primary difference between patches and turtles is that patches cannot move. Patches also take up a defined space/area in the world; thus, a single patch can contain multiple turtle agents on it.

Links

Links are also unable to move themselves. They connect two turtles that are the “ end nodes ” of the link, but the visual representations of the links do move when their end nodes move.

Links are often used to represent the relationship between turtles. They can also represent the environment — e.g., by defining transportation routes that agents can move along, or by representing friendship/communication channels. Despite these differences, all three share the ability to behave, that is, to take actions and perform operations on themselves.

Breeds of Agents

Besides these three predefined agent-types, modelers can also create their own types of agent called breeds. The breed of an agent designates the category or class to which the agent belongs. In the Traffic Basic model, all of the agents are of the same type, so it is not necessary to distinguish between different agent breeds. Instead, we used agents of the “ turtles ” breed, the default breed in NetLogo. Different breeds of agents are required if different agents have different properties or actions.

Wolf and sheep

we had two breeds of agents, the “ wolf ” the “ sheep ” breeds. Even though these two breeds had the same set of properties, it was useful to create two breeds because

each had different characteristic actions — wolves eat sheep, while sheep eat grass. We defined the breeds at the beginning of the model:

At the same time, we can define the properties that breeds have:

In this case, both the wolves and the sheep have the same property of “ energy, ” but we could also give them separate properties. For instance, we could give the wolves a “ fangstrength ” property and the sheep a “ wooliness ” property. The fang-strength could be used to determine how successful a wolf is at killing sheep. Wooliness, by contrast, could be an indication of how well the sheep was able to fend off the wolves ’ attack, if we assume that the wolves sometimes get a mouthful of wool instead of flesh. If this were the case, we would add two additional lines: