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Lab 6: The construal comprehension exercise

This lab will be devoted to work on the construal comprehension exercise as set out here. This exercise is required coursework for the MSc students studying CS405. It is also helpful for MEng students as a possible source of inspiration for your WEB-EM-8 submissions and because these construals will be the subject of the first - and only compulsory - question on the examination paper.

Further clarification for the construal comprehension exercise

For the construal comprehension assignment, you will generate:

  1. an EMPE presentation of the observables, dependencies and agents in your allocated construal.
  2. a list of key observables in the model (recorded in the observable 'listobs' using the symbolinfo tool) together with a list of descriptions of these observables (recorded in the observable 'listinfoobs' using the symbolinfo tool).
  3. a handout of not more than 5 A4 pages giving additional information about your construal.

Item 1 will be recorded in an Eden file which will be called intro.eden. (This is a revised version of the original intro.eden file which is given in your presnameofmodelAUTHORyear directory.)

Item 2 will be recorded in the definitions of listobs and listinfoobs which you generate using the symbolinfo tool - these definitions should be appended to the run.eden file in your presnameofmodelAUTHORyear directory.

Item 3 is a pdf file that you may wish to print out and distribute at your presentation session next Tuesday 12 noon to 1.30pm. This is the most appropriate way in which to present any output from the DMT (see below).

Items 1, 2 and 3 must be submitted via the BOSS system before the deadline of 12 noon on Tuesday 15th November.

All students are expected to attend the presentation session in CS0.01 on Tuesday 15th November and be prepared to deliver their presentation at any time between 12.10pm and 1.30pm - attendance will be taken into account in awarding marks.

Using the Dependency Modelling Tool (DMT)

The Dependency Modelling Tool (DMT) can be downloaded from the directory dmtWong2003 in the EM archive. It is a Java application that can parse eden scripts and display graphs that depict dependencies between observables. When you run the DMT v0.72, it brings up a window with buttons for drop down menus at the top

For the purposes of the construal comprehension exercise, you should select the 'Input window' option from the 'Script' menu, and enter EDEN definitions of observables that you have recorded using the symbolinfo tool. To get an idea of how this works, you should first enter a few random Eden definitions - such as

a is b+c;

b is 2*c;

c =35;

d is [a,b,c];

via the Script Input Window, and inspect the graph of dependency relations displayed in the DMT window. You can manipulate the location of nodes in this graph by selecting them by depressing the left mouse button and moving the mouse. You can also delete nodes by double-clicking with the mouse button.

To simplify the process of transferring definitions from the symbolinfo tool into the DMT Script Input Window, a simple file of EDEN commands called 'outputdefns.e' has been placed in the /dcs/emp/empublic/teaching/cs405/UsingEMPE/syminfoBeynon2011 directory. It is important to ensure that when you execute this file of commands, the EDEN interpreter is in a directory in which you have write permission - the interpreter will otherwise crash! (You can check the current directory in which the Eden interpreter is operating by invoking the command writeln(cwd()));). When you then execute this file from the Eden Input window, a file called somedefns.e containing all the non-explicit Eden definitions recorded by the symbol info tool is generated.

Some things you may wish to consider in making your presentation

For this exercise, the sole requirement is that you demonstrate that you are familiar with observables and dependencies in your construal and have identified the agents that might manipulate these.

When making your presentation, it may be helpful to consider issues such as:

  • describing the context for the construal
  • demonstrating how it can be used
  • explaining how it illustrates EM principles
  • exposing the observable and dependencies in the construal
  • summarising the pros and cons and potential of the construal.