The model page lets you navigate through the model and review all equations, values and dependencies. If you have a library of components, you can also use the model page to assemble a model by retrieving and connecting components from the library.
As in Ecolego, the model is visualized using an interaction matrix. Components are displayed on the diagonal and their relations on the off-diagonal elements. Once you select an item in the interaction matrix, information about the selected item is displayed in the text box to the right.
The menu for the model page has buttons for display options and for managing the library.
|Manage library…||Opens a window that lets you import components to your local library. See setting up the library.|
|Auto-zoom||When selected, the size of the interaction matrix will adjust to always fill the window. While this button is selected, the other zoom buttons are disabled.|
|Zoom selected||Zoom the selected cells of the matrix. When no cells are selected, the whole matrix will be displayed.|
|Zoom In||Increase the zoom factor.|
|Zoom Out||Decrease the zoom factor.|
|Help||Displays this help page.|
The interaction matrix is used to visualize the model. Important model components are displayed in the diagonal of the matrix, and connections between the components are displayed in the off diagonal elements in a clockwise fashion. This means that a connection from A to B is displayed in the cell on the same row as A and in the same column as B.
Large models are often divided boxes called sub-systems. A sub-system component has a thicker border, and when you move the mouse cursor over it a small plus (+) sign is displayed. When you click on the plus sign, the sub-system is expanded so you can see the components therein.
When you select items in the matrix, information about the selected items is displayed in the information text box.
On the right hand side is a white text box named Information. When you select one or more objects in the matrix, this window will give you information about the object(s), such as name, description and equations or values. The window is similar to a web page - each listed object has a link to the information page for the object. This way, by clicking links in the information box, you can navigate through the equations and relations to see how the model is constructed.
If you have access to a library of model components, you can use the interaction matrix to assemble a model for your assessment.
A model component is a sub-system with defined potential inputs and/or outputs. An output for one component can be connected to inputs of other components. When an input is connected to another model component, you do not need to supply values for this input.
Consider the following example:
The library contains a set of components for creating a model of a landscape.
One component - Soil - can be used to model the turnover of contaminants in agricultural soil.
Another component - Plant - models the uptake of contaminants in a plant.
An assessor needs to investigate impact of release of contamination from a site on plants growing in the region. Thus, he starts by adding a Plant model to the interaction matrix.
The Plant model has a time dependent input for the concentration of contaminants in the soil. The assessor, however, lacks measurements for the soil concentration - he only has measurements of the release rates from the site.
Thus, he adds a Soil component. The Soil component has a time dependent output giving the concentration in soil as well as inputs for the contamination rate of the soil. This way the assessor can, by connecting this output to the corresponding input of Plant, model the concentration in soil and just enter the release rate.
Model components are packaged in files with the extension .ecl. If you have such files, you can import them to your local library:
A component can consist of many objects - parameters, time dependent lookup tables, expressions and compartments. The model creator can define some of these to be (potential) inputs, and some to be (potential) outputs. This means that if you lack the data for a specific input, you can use another component to calculate it for you.
To connect two components, where the first has defined outputs and the other has defined inputs:
Make sure that both components are “closed” or “collapsed”.
Right-click the matrix cell which is on the same row as the first component and in the same column as the second component.
From the menu, select “Connector”. An arrow pointing from the first component towards the second appears in the matrix.
Double-click the arrow.
The window that appears has three pages:
Properties allows you to enter a new name for the connection.
Matrix allows you to change the image, color and font for the connection.
Values lets you connect outputs of the first component with inputs of the second component.
On the left hand side of the table, in the From column, each defined output of the first component is listed.
On the right hand side, in the To column, you select which input of the second component to connect the corresponding output to.
If you add a new component to the matrix, and there are already components in the matrix, you might be asked if you want to automatically connect the inputs of the new component to outputs of existing components. This happens when:
Note that automatic connection will only connect the inputs/outputs where the above requirements are fulfilled - the remaining connections you must do yourself.