Simulation with AnyLogic/System Dynamics/Step 5. Adding constants

''' Step 5. Adding Constants '''

Now we will define constants of our model. In AnyLogic you define a constant by creating a parameter.

Define a constant representing total population


 * 1) Drag the Parameter [[File:Step_3._Adding_Adoption_from_Advertisement1.gif‎]] element from the System Dynamics page of the Palette view onto the diagram of active object class.
 * 2) On the General page of the Properties view, set up the parameter properties.
 * 3) Change the name of the constant. Type TotalPopulation in the Name edit box.
 * 4) In the Default Value edit box, type 100000. This will be the total population in our model. [[File:Adding constants 1.png]]

The rate, with which potential adopters come into contact with adopters, is assumed to be constant. So, we will define a constant to represent contact rate.

Define the ContactRate constant


 * 1) Define the constant in the same way. Enter the Name: ContactRate.
 * 2) Assume a contact rate of 100 per person per year. In the Default Value, type 100. [[File:Adding constants 2.png]]

In this model the volume of advertising and the probability that a potential adopter will adopt as the result of exposure to a given amount of advertising are assumed to be constant each period. So, we will add a constant to model the advertising effectiveness — the fractional adoption rate from advertising.

Define a constant representing advertising effectiveness


 * 1) Define a constant in the similar way. Name it AdEffectiveness.
 * 2) Set the value to 0.011. [[File:Adding constants 3.png]]

Define one more constant to specify the adoption fraction — the proportion of contacts that are sufficiently persuasive to induce the potential adopter to purchase the product.

Define the AdoptionFraction constant


 * 1) Name the constant <tt>AdoptionFraction</tt>.
 * 2) Set the value to <tt>0.015</tt>. [[File:Adding constants 4.png]]