In paramRestDef, the refIDs show the IDs in the original model, which are to be combined into a new parameter (like a, b, g in source monitoring experiments), and the parameterString shows the new parameter name.

Therefore, we will have as many paramRestDef nodes as the new parameters that combined from original model nodes.

As well, we use refID to express the ID of the ending nodes of each branch, and use category to show the observed categories of these ending nodes respectively.

In treeDef, we use refID to denote the root ID of a tree, and frequency to the total frequency observed in this certain tree.

The main part of the original model is the source trees. For instance, in a typical source monitoring experiment, we may have source trees A, B and N. Moreover, the nodes under a tree denotes the processing steps and their sequential relationship.

 Main Structure of the project shows the three basic parts of the project: originalModel, subModel, and dataSets.

Original Model is a collection of trees. It is used to represent the structure of the original processing tree model in which no parameters or branches are combined. In other words, every single step/node in the tree has a unique parameter name.

Sub Model  represents the sub models we intend to test. In this part, we use treeDef to define the root node of each processing tree and use  nodeDef to define the ending nodes paired with their categories respectively. As well, we recruit paramRestDef to define the nodes that share a same parameter in the sub model. Please note that we can have more than one sub models here if we merely create another set of these definitions without indicating the tree structure/nodes' relation that has already been fixed in the original model.