Lab 2B: Understanding the Lift Model
This lab is an exercise in 'construal comprehension'. The techniques and tools illustrated in the lab are essential preparation for making your own construals. They are also the basis for the first assignment, for MSc students only, which is worth 10% of the coursework credit. As in Lab 2A, the use of EDEN is scaffolded by the Empirical Modelling Presentation Environment (EMPE).
You are intended to study the lab with a partner and to work on adjacent workstations. You and your partner will configure two different interfaces to the Lift model. By examining the Lift model from two perspectives, you will find it easier to examine the observables and dependencies in detail.
In the course of this lab, you will first set up your own private work area for CS405 coursework and make your own copy of the /dcs/emp/empublic/teaching/cs405-2011/UsingEMPE directory within it. The presliftBeynon2003 subdirectory of this directory contains the resources you need to run the Lift construal in the EMPE. Explicit instructions for the setting up procedure can be found in an Appendix to this lab.
Once you and your partner have both set up your independent copies of the Lift model in the EMPE, you will be able to follow the further guidance given in the EMPE model itself. Your initial task is to configure the dual workstation environment for the comprehension task. In this environment, one workstation will be devoted to the EMPE and the other to the underlying tkeden interface, a text editor window, and a special purpose 'symbol info' tool for recording observables. View1 and View2 are images of the two interfaces to the model to be set up, as they should be displayed on your two workstations: these can also be viewed concurrently in the Appendix to the lab.
For background information, you may find it useful to refer to the webpage Using the EMPE mentioned under Further Study in Lab 2A, and to the instructions for using the symbol info tool.
Reflection on Lab 2B
The instructions for this lab reflect the fact that making EM construals is a process without clearly specified boundaries. As you become more familiar with the EM tools and make your own construals, you will need to explore for yourself and improvise in ways that cannot be set out in a recipe. The 'symbol info' tool illustrates the way in which useful activities can be supported by building informal extensions to an EM construal. EM requires a blend of manual and automated activity that more closely resembles 'playing a musical instrument' than 'operating a machine'. The balance between manual and automated activities typically changes as the construal matures. For instance, a change of state that is at first described by typing directly into the Input Window may later be realised by copying-and-pasting from a text file, then by the manual loading of an entire file, and finally by the automatic loading of the file in the appropriate context. The basic UNIX skills introduced in this lab are valuable in supporting these evolving modes of interaction.
Lab 2B also illustrates another theme that is characteristic of EM: the idea of disposing resources so as to support fruitful interaction. This relates to the notion of 'efficacy' (cf. the contrast Steve Russ draws between traditional computer science and EM. See also Eric Chan's PhD thesis).