The demo version requires the following hardware and software:
- An 80486 or Pentium-based IBM or compatible computer.
- At least 16 megabytes of memory.
- A hard disk with at least 2 megabytes of free space.
- A monitor with a resolution of at least 1024x768.
- Windows NT 3.5 or later, or Windows 95.

The demo software files are compressed into a zip file: lake.exe.
To install the demo version, follow the following instructions:

- Unzip lake in the directory of your choice, for example c:\lake,
by moving the lake.exe file to the directory of your choice and
then type lake in this directory and then press return.
Then a number of files will be generated in the selected directory .
- To start the software, go to the Start menu and choose Windows Explorer
from the Programs menu.
- Go to the drive and directory where you have installed the software;
In this example c:\lake
- Double click on the file demo.bat. Note: depending on the settings of
your Windows Explorer software the extensions ".bat" may be hidden.
- Option: you may create a shortcut by selecting the appropriate ".bat" file
and choosing the option Create Shortcut from the File menu.
You can drag this shortcut to your desktop.

User's guide

For the visualization of the model, the M-software (
has been used. The visualization within this graphical interface software consists of views.
Each view consists of a number of levels, made up out of boxes (within boxes) and sliders, buttons, or graphs.
After starting the program as described in the installation procedure, the first view will appear.

This view appears when starting the model.

From now on the program is mostly mouse-operated.
Depending on the location of the mouse there are a number of operations that can be performed using the mouse buttons (more information below).

If you press on the button start model, you will derive a new view, with a blue and a green button. You can choose to view the variables of the lake or the lake managers (farmers).

If you have chosen the lake, you will get a view that contains closed boxes of the most important variables.

You can open the boxes if you put the mouse cursor at the empty space below "Mud equation", push the right button of the mouse, and "open all". Note that the horizontal axis represents time. In the default case, the model ran 100 years, but this time horizon can be expanded by Options -> Model -> Max:
The variables listen in the view are:
L = the input of phosphorus in the lake
q (exponent) = affects the steepness of the sigmoid curve
scaling factor uncertainty = sf in the paper, the higher the more random influence on the input of phosphorus in the lake
s (sedimented) = proportion of P sedimented each year
k (permanent burial) = a small portion of the phosphorus in the mud is lost each year to permanent burial
h (flushed) = the proportion of P flushed each year
r (recycling) = maximum recycling rate of phosphorus
P = amount of phosphorus in the water
P0 = phosphorus value at t = 0
M = phosphorus in mud
M0 = initial value of M
f = value of sigmoid curve
Mud equation = one can exclude the mud equation of the biophysical system

If you have chosen for the lake managers, you will view:

with the variables:
expected value of P = according to the various perspectives compared with measured value
start distribution perspectives = allocation of perspectives at t = 0
b = constructed b value as described in the paper
ignorance of changes in P = the epsilon value as described in the paper
Average perspective = the distribution of the three perspectives
Average fitness of perspectives = the higher the fitness the better the perspectives explain the observations
Variance of perspectives = a measure of the variance of opinions
Learning = one can assume that agents do not learn; distribution of perspectives remain the same

An example of changing parameter values is given in the next view, in which the start distribution of perspectives is changed, leading to different results.

Suppose you enlarge the ignorance variable to 1.0; then the adaptation slows down.

Use of the mouse
At the menu bar at the top of the screen, a menu can be found with a number of specific items.
For using the software, the number of menu options has been restricted.
Below is a list of all menu items you can use. The other items cannot be used in this version of the software.

Menu Item Action
File Print Opens a menu to print the screen to printer or to a file
Exit Exits the model
Tools Scenario manager For saving and opening input scenarios
Viewer Options Freeze and rerun the model
Help About Gives information about the version of the M-software used

1. Disabled menu options are grey colored and will not be described.
2. A graph can be made active by pressing the left mouse button in the graph.
3. Whenever settings are changed, they have to be confirmed by a <return> before they will be activated.

The View Options is helpful because of the Freeze option.
After activating Freeze, you can change the inputs without direct rerunning of the model.
You have to press the Freeze button again to rerun the model.

If you press the right mouse button in a box, a menu will pop up.
Below is a list of all the possible menu items.
Note: Not all of the items will be shown at all times, e.g., if a box is already open, the menu item Open will not appear. There are some menus with a number of options that are disabled. These options are grey colored and will not be described.

Menu item Action
Open Opens a box
Close Closes a box
Open all Opens all boxes under the current level
Close all Closes all boxes under the current level
Zoom in Zooms in on a box and opens it
Zoom out Zooms out from a box
Reset Resets the contents of all boxes under the current level to their default values
Set reference Set the value of all boxes under the current level of a reference level, which will remain visible when one or more of the values is/are changed
Unset reference Removes all references of all boxes under the current level
Load ... Loads data from a data file into a box
Save ... Saves data from a box to a data file

When the mouse pointer is positioned within a graph, a menu with different options will appear. From the first four options (Show value, Drag, Scale X, and Scale Y) one option is always active. This option defines how the left mouse button will act.

Menu item Action
Show value Shows the location of the mouse pointer in XY coordinates.
Drag Enables one to drag the graph to shift the scale of the X and / or Y-axis.
Scale X Enables one to change the range of the X-scale.
Scale Y Enables one to change the range of the Y-scale.
Edit free Enables one to change the graph freely by dragging the line.
Edit line Enables one to change (parts of the) graph linearly.
Edit expo Enables one to change (parts of the) graph exponentially.