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Department of Computer Science

Revision notes for the CS405 examination 2010

The examination paper carries 50% of the module credit, has 5 questions on it (of which you should attempt 3) and is marked out of 50. The first question is compulsory, and carries 20 marks. The remaining 4 questions carry 15 marks, and you should answer two of them. CS405 is a three hour examination. This gives you ample time to think and write. For instance, if you spend approximately 70 minutes on answering question 1, and about 50 minutes on each of the other two questions, you will still have 10 minutes for reviewing your answers overall.

The CS405 lectures cover a very broad range of topics, and I appreciate that it is hard to find a suitable focus for your revision. My intention in these revision notes is to give you sufficient indication of the kinds of topics to be addressed in questions 2-5 to enable you to make a choice in advance about which two of these questions you wish to answer. For each of these questions, I shall give you pointers to the principal sources within the lecture notes and labs that you should consult in revising for them. Of course, it is in your interests to get as much broad familiarity with all the lecture material as possible. Much of the material is interconnected. It is also useful to be able to cite standard examples of models that we have studied in the course of the module.

The format of the examination has been the same for the last few years, apart from the fact that it used to be marked out of 100, and the specific topics change from year to year. (This year's paper will look a little different as it has been prepared in Latex rather than Word.) Here is a brief summary of the themes of the five questions on the paper.

Question 1: 20 marks

This compulsory question is concerned with the core ideas of EM, as illustrated by the EDEN model sudokuexperienceBeynon2009 introduced in Lab 5. If you have only engaged with the practical side of the module through using DOSTE, it is most important that you should study Lab 5 and become sufficiently familiar with EDEN to answer this question. (Note carefully that Lab 5 was problematic because we were unable to run it successfully using Web EDEN at that time, so it's important that you should invest time in it now in preparation for the exam.)

Key issues here are understanding what is meant by observables, dependencies and agents, and appreciating why it is generally appropriate to interpret an EM model in several different ways according to how you choose to interact with it and interpret that interaction. It will be important that you are familiar with the script for the model, and can identify the key dependencies in the model. Workshop 2A is particularly relevant, as it illustrates how the definitive notations Scout and Eddi are exploited.

At a meta-level, you should consider what it means for the sudokuexperienceBeynon2009 to be viewed as an artefact, a construal, a model and a program. For this purpose, you should identify (through studying Lab 5) how different modes of interaction and interpretation of sudokuexperienceBeynon2009 are associated with viewing it as an artefact, a construal, a model and a program.

Question 2: 15 marks

The theme of this question is "DOSTE vs EDEN" as a tool for EM. This topic was addressed in many lectures in the module e.g. Lectures 1, 4, 5 and 7. To tackle this question, you should be familiar with how to use and interpret DOSTE, as illustrated in the first four labs. A useful focus for your revision here is on what were identified in Lecture 7 (cf. Lecture 4) as "the three key concerns". In answering this question, you should be prepared to give illustrative examples of DOSTE and EDEN. These can be drawn from standard examples (e.g. Stargate, OXO or Sudoku) or from your own coursework (provided that you provide enough context to make your answer understandable).

Question 3: 15 marks

The principal theme of this question is the actual and potential use of dependency in modern software development. This theme was addressed by Antony Harfield (see Lecture 5 "Dependency in Action") and developed in Lecture 12 (notably in the discussion of "dependency by definition in Imagine-d Logo"). To answer this question, you will need to be familiar with relevant features from e.g. the Windows Presentation Foundation and Adobe Flex such as were discussed and illustrated in Lecture 5, and be able to relate these to the way in which dependency is handled in DOSTE and EDEN. You will also need to appreciate the challenges that we face if we try to "bolt-on" dependency to a conventional software development tool. For this purpose, you should be familiar with the discussion of the Imagine-d Logo prototype and the conclusions reached in that discussion.

Question 4: 15 marks

This question is a practical question about EM. Its focus is on the fact that a particular artefact can be interpreted in different ways (cf. the "cabinet digit" model discussed in Lecture 7). Depending on how you interpret an artefact, you will set about constructing it using EM in different ways - identifying different observables, dependencies and agents, and thinking of different metaphors for representing them. These metaphors in turn will lead you to use different notations - such as the definitive notations associated with EDEN and DOSTE (as represented by DASM). In this question, you will be presented with an artefact and asked to explain how you would go about applying EM when taking different interpretations (cf. how a digit is modelled quite differently from a filing cabinet).

Question 5: 15 marks

This is a broad essay-style question. It draws on a variety of themes discussed in the module that relate to the idea of linking computing activity to the essentially human processes of reflection and construction. A key notion here is that of construal, as introduced in Lecture 2, and developed throughout the module. Other relevant sources are:

  • Lecture 8, which considers Ben-Ari's reservations about "Constructivism in Computer Science Education" (Ben-Ari sees the computer is "an accessible ontological reality" - slide 6), and critiques this assumption using my construal of the vi editor for illustrative purposes.
  • Lecture 12, which revisits Papert's notion of constructionism, and critiques this by contrasting room models constructed using Logo and using Donald.
  • Lecture 17 on Human Computing, which examines EM in the context of Licklider's vision for (Hu)Man-Computer Symbiosis.


By way of general guidance, in making your choice of questions, you should consider carefully what background knowledge and experience you need to tackle each question. Though you may wish to specialise on DOSTE or EDEN as the principal EM tool of interest to you, it is essential to be sufficiently familiar with EDEN to answer question 1, and to know at least the basic principles behind DOSTE as a conceptual and practical tool. You are strongly advised to come to the examination having devoted focused attention to the specific topics highlighted in these revision notes in connection with Question 1 and two other questions of your own choosing. Also please bear in mind that I appreciate the difficulty of writing about EM, especially if English is not your first language, but you should not feel imtimidated by this. I can only award marks for what you write!