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Creating A Network
There are two ways to create a problem in the Belief and Decision Network Applet.
Load A Sample Graph
This is the way to load a prebuilt Bayes graph or Decision network. You can load from a set of
sample problems, or load from a URL.
On the menu bar, select File->Load Sample Graph. A dialog will pop up
with a choice of sample problems. Choose one.
On the menu bar, select File->Open Location. Type in the URL of the graph, and click load.
Create a network manually
Click the Create mode tab to display the Create panel. Click on the Create Node button and then click on
the canvas. A dialog will pop up to ask the user what the node's name is and what is the domain of the node. Click
'Done' to create the node. Place additional nodes in this manner. To create arcs, click the Create Arc button
and click on a node to define the starting point of that arc. Click on another node to define the end point of that
arc. Arcs define probabilistic dependencies. To modify a node's probabilities, click the Modify Probability Table
button and click on the node to be modified.
If the user wants to create a Decision Network (as opposed to a Belief Network), go to Network Options->Belief/Decision Mode and select Decision Network Mode. This will allow the user to set the node type as normal, decision, or
while creating nodes.
Solving A Problem
Click the Solve mode tab to go to Solve mode. Click the Query Node button. If the
network is a Belief Network, one can query nodes immediately. However, if it is a Decision Network,
some nodes (particularly decision nodes) cannot be queried until the network is optimized.
Clicking on the Optimize Decisions button will optimize the decision nodes.
There are two ways to solve a query. To switch between modes, go to Network Options->Query Modes, and
select either Brief Query Mode, Verbose Query Mode, or Prompt For Query Mode. If Prompt For Query Mode
is selected, every time a query or optimization problem is solved, a dialog will pop up prompting
the user to select either Brief or Verbose Query mode.
Brief Query Mode. Just click on a node after depressing the Query Node
button. This will solve for the probabilities of the domain of the node, and
will pop up a dialog informing the user of the results of the query.
Verbose Query Mode. Clicking on a node after depressing the Query Node button will pop up
a new canvas where the user can manually do variable elimination.