Modeling City Model Example

Modeling: The model will have a chance (nature) node for each context information (such as age, religion etc.). These modes represent information about the user and thus also questions that will be presented to the user at the website.

At the beginning all values have some default value.
For each activity there will be 3 nodes: a chance node describing how much the user likes it on a scale of 1-5 (where each inner state: 1-5 will have a value of 0.2 probability), a decision node of whether or not the activity will take place and a value node. The value node will tell us how much we benefit from this activity. Some default values need to be inserted with some sense. For example, value node for going to the mall: in case the user wants to go to the mall we will get more than if he didn’t want to. Also negative values are possible here (up to the designer).
The value node will have as parents the decision node, the relevant chance node, and other decision nodes that are relevant to this activity (example: if you already go to a mall, a second one would be less desirable etc).

For each activity we will compute two things with the Smile engine:

1. The value of information of the chance node of this activity.

This enables us to calculate the total value of a schedule – by combining all the values of chosen activities. 

2. How much he is expected to like it -- this is the expected value of the "like" node.
Using these two items of information, we rank the activities on the top-right.

Ranking the questions - Here we compute the value of information of the different questions and use it to rank them and infer what questions are needed next.

*Note that value of information is a function that we get from the Smile API.

In case a user ranks an activity, removes it from a schedule or searches for it, we will update the model by changing the probability of the chance node that describes how much the user likes the activity. The way it changes it can be decided at a later stage.

In case a user answers a question we will update the model by changing the probability of the nature node that describes that type of activity – see appendix 5.4.

 

Here is an example of a mini model consisted of two types of activities and 3 possible activities.