So here is one of my recent exam papers, with comments on how I would go about trying to answer it. I put myself in the shoes of a student faced with these questions.
Disclaimer: The advice contained here is only advice, and it is also not fully complete advice. Do NOT take these thought too rigidly. Do not come back to me and say 'but you said ...'. I just offer this in good faith, and hope it might be useful to some people.
Answer any 2 questions.
Two questions in one and a half hours. Take five minutes off for reading the questions and another ten minutes off for any tidying up or emergencies, and that leaves 30 minutes per question. That means: 3 marks per minute on average. I'll bear that in mind as I plan how to answer the questions.
Two questions, out of how many? Four. I need to select two from the four - gives me plenty of scope. But I'd better look over the questions and see which ones I think I can answer well. Which ones are in the general areas that I have most understanding of. In particular, I should look at the last parts of the question, because those are the hardest parts; the first parts are often bookwork.
In general, as examiner, I tend to structure my questions as follows (BUT BEWARE: A SIGNIFICANT MINORITY OF MY QUESTIONS HAVE A DIFFERENT STRUCTURE):
| Part a): Ask the student for a bit of bookwork, a bit of regurgitation of something in the course. | This part sets the scene, suggests that the question is going to be all about. | This part could probably be answered largely from the lecture notes. |
| Part b): Ask the student to give something deeper about part of what I asked for in part (a). | This part probes the student's understanding. Also it might prepare the student for answering the later part(s). | This might require some wider reading that I asked the students to do, or material that was discussed in more depth during the lectures or in one of my papers. It probably requires stuff from textbooks that I recommended, or any equivalents that the student has chosen. |
| Part c): Now ask the student to go further, and to go beyond what was in the course. I might set up a scenario and ask the student to discuss it, or might ask them to discuss some experience from their own lives using the concepts related to the question. | To test whether the student really understands this matter, to the extent that they can apply it in situations not presented on the course. I am testing whether the student can differentiate between what is relevant and what is not. |
The first parts of the question usually prepare for this part, so should be seen as a resource.
Here I might expect the student to bring in wider reading, or their own (relevant) experiences. |
Disclaimer: I do not guarantee that all my questions will be structured in this manner; I do not even guarantee that any of them will be. Therefore you should use the ideas above to understand the kinds of things I seek in questions, rather than as a rigid framework.
a) Explain the differences between a knowledge based system and a data base. (30 marks)
How much time to give to this? 30 marks, 3 marks per minute: 10 minutes. To plan and write. However, since the start of questions is usually easier book work, I should try to do it in a bit less time, so as to leave a bit more time to part (c).
'Explain'. This is half way, in amount of detail expected, between 'describe' and 'discuss'. It means that I have to say not only what the differences are (which would be description) but also what makes those differences come about - that is, the foundation of those differences. However I don't have to discuss the implications of the differences (which would be 'discuss'.)
b) Explain what inference engine, backward chaining and forward chaining are, and discuss how they make a knowledge based system seem 'intelligent'. (20 marks)
20 marks: about 6 minutes for this. The examiner expects less from this part than from the previous, but not much less. In part (b) of a question I am often expected to elaborate on what I said in part (a), so go a bit deeper, using course material. Three 'explains' and one 'discuss'. So, perhaps 3 minutes for 'discuss' and one minute each for the explains.
'Explain' again. What these things are and what is the foundation of them. But also, since there are several things to explain, I should also say something about the relationship between them. Inference engine involves the other two.
'Discuss'. This is more than explain - though in 3 minutes, it is perhaps only a partial discuss. It means that I have to say something about 'why'; I have to give reasons or implications. Normally 'discuss' implies giving reasons for and against, to give both sides of an argument rather than just one view, and to bring in what other people have said for and against. But only 2 or 3 minutes for this discussion, so not deep. Only give some reasons why inference engine and two types of chaining seem to make a KBS seem intelligent. Can I think of one reason connected with each of the three:
c) Discuss the similarities and differences between inference nets and rules as knowledge representation languages. (50 marks)
50 marks. That's a signal that this is the most important part of the question. Together with the fact that it's part (c). However, I'd better plan to spend at least half my time on it.
However, the first parts of the question lead up to this one, so I should at least be thinking along the right lines at the moment.
I can remember that we covered the differences and similarities in the course. So that will provide most of the material for this, but much of that discussion was in the lecture time rather than in the notes. So, can I remember it? Let's put down some rough ideas first.
'Discuss'. I need to state first what those differences and similarities are, and then give reasons for why they arise. Also I need to say something about the implications or importances of those similarities or differences.
The wording of the question suggests a format for my answer: A heading 'Similarities' and discuss those, then a heading 'Differences' and discuss those.
But after the former I should leave a few blank lines before the latter, in case I think of more similarities or more to say about them while discussing the differences. In particular, implications often occur to me while i am writing other things.
a) Explain what roles, tasks and features are. (30 marks)
'Explain'. As above, I need to say What these are and what is their foundation. Since there are three of them, I must also say something about the relationship between them.
I must be very careful, however. The words 'roles', 'tasks' and 'features' are used with many different meanings by many different people. Therefore I must explain what they meant on the course and not elsewhere.
I can then expect the rest of the question to develop my thinking about roles, tasks and features.
b) Consider the following account:A certain knowledge based system (KBS) was designed to help quantity surveyors to predict more accurately the budget that should be set for a new building. It would ask about 30 questions and then propose a budget, which could then be broken down and explained. It took into account many exceptional circumstances and was deemed highly 'intelligent' and very usable. It was expected that surveyors of lower degrees of experience would be able to undertake budget-setting. But it was found in practice that the senior surveyors, who already possessed much of the expertise, used the KBS, because it enabled them to check and explain their own expertise. The use of the KBS brought about a change of relationship with their clients, from expert-novice to two partners working towards a shared goal. This was because they changed their ways of operating with the clients, from simply receiving the client's requirements and calculating a suitable budget, to a two stage process, of giving a rough figure quickly and then working with the client to refine the figure. The latter was made easier because the KBS allowed the user to change answers already given to questions and to override assumptions made in the KB. It helped the client to clarity and refine their requirements.
Identify all the features, tasks and roles mentioned in this account. (50 marks)
50 marks. The most important part of the question. Take half the time. Some of the time will be taken with reading and identifying; the rest with writing.
'Identify'. I only have to pick them out and say whether they are a role, a task or a feature. I don't have to explain or discuss.
However, I might have to justify my decision. In some of them it might not be fully clear which something is. So I might have to say something like "This can be seen as either task and feature; feature if ... and task if ...". Or "I treat X as a feature because ... [and refer back to what I said in part (a)]."
'Identify all'. This means the examiner wants a complete list. Does this help me to know how many of each? Well, probably if I find only half a dozen then I have not found enough. (Actually there are 50, though the examiner did not expect all to be found; the top-marked student found 30, and that gave nearly full marks.)
Format of answer. 'Identify' invites me to just give three lists (of roles, tasks and features) - just bullet points. No lengthy prose. In fact, the examiner finds bullet lists much nicer to mark.
Maybe more than three lists? Maybe some things are both role and task etc. Either those things would go into both lists (duplicated) or there might be extra lists headed 'Role-Task' etc. That would depend on the subject. (In fact, in this particular case, you should NOT use composite lists, only the three basic ones, and duplicate.)
c) Discuss, with reference to the above account or other uses of sofware, how features can enable or hinder tasks, and how tasks can help people fulfil roles, and how the insertion of features into a working situation can change the task profile and how this can change the roles of people. (20 marks)
20 marks. Not much wanted here. Only 6 minutes' worth. But because it is part (c), it needs to be high quality stuff I give. So maybe a bit more than 6 minutes.
'Discuss'. As above, give reasons and implications, and give for and against. In this case, the for and against could be 'enable' and 'hinder', or it could refer to 'enable or hinder' on the one hand, versus 'have no effect' on the other.
It seems there are four sub-parts to this part:
two relating to the relationship between features and tasks, and two relating to that between tasks and roles. This has implications for the format of the answer and also how much time I give to it, and also to what I select as an example to refer to.
Format of answer. A useful format, therefore, would be to have one paragraph on each, or perhaps one sub-section with heading for each. That would help my thinking, and also make it easier for the examiner to see what I am getting at. However, in some cases, it might not be possible to neatly differentiate like that. About 1 or 2 minutes on each.
".. with reference to the above account ...". This is important, and many students overlooked it and forfeited marks by doing so. It means that my discussion of the four things should refer to things in part (b). I should therefore look for hints in the account on features that led to enabling tasks and ones that led to hindering tasks (it might the same feature that enabled one task and hindered another). And likewise for each part. Given that there is only 1 or 2 minutes for each, the examiner probably expects only one or two examples in each category. But there's more ...
Because the part began with 'discuss' rather than 'indicate', this implies that the links between features, tasks and roles might not be explicitly stated in the account. Rather, I would have to use my common sense. For example, the ability to change answers to questions (a feature) could help in the checking and explaining of ideas (two tasks) - this link is not explicitly mentioned, but seems reasonable.
Answering the last part of a question can often improve answers to previous parts. For example, as I answer this part of the question, I might see other features, tasks or roles in the account that I did not see before. So I would go back and add them to part (b) answer. Or I might think I have misclassified something, so I would go back and modify part (b) answer. Therefore I should have left some blank space before starting part (c) in order to accommodate such changes.
".. with reference to ... or other uses of sofware, ..." This gives me freedom to bring in another example, instead of using the above account. I would do this if I did not get on well with the account, or do not believe I can make the necessary common sense links mentioned above. If I'm going to do this, it should be some use of software with which I am very familiar, such as my use of email or word processor. And I should try to find an example, therein, of each of the four links above.
a) Briefly outline and explain the issues that need to be discussed at an early stage in the development of an Expert System, in order that a useful system is developed and brought into widespread use. (40 marks)
40 marks: 40% of 30 minutes: 12 minutes.
'Briefly outline and explain'. This is like an explanation, but need not be too detailed. 'Outline' means say what the issues are, which is of course part of explanation in this case. For example, can I think of some taxonomy of issues that were presented to me on the course that deal with early stages of development?
'Briefly' suggests that I should try to cover everything. Breadth rather than depth. It indicates that the examiner thinks that there are many issues, and that each one of them discussed in detail would take far more than 12 minutes.
Note how this can help me think of issues. If I find I have run out of things to say in 10 minutes then there is probably some issues that I have totally forgotten. I should try to think of what they are.
".. in order that a useful system is developed and brought into widespread use." This gives me a clue as to what types of issues the examiner is thinking about. It does not talk about user interface, nor about technical excellence, but about usefulness and widespread use. (Not that user interface and technical excellence are to be ignored; they might be relevant as part of the answer, but this wording suggests they are not the main issues.)
"early stage in the development .." In real life, many students spoke about all stages. That material was irrelevant to the question. Not only did that waste their time (because they were taking time writing it) but it can annoy the examiner and lose marks. Moreover, it tells the examiner that the student doesn't really understand the topic. Beware.
b) Discuss the strengths and weaknesses of rapid prototyping and a linear, specification-based approach to software development. When would each be appropriate? (30 marks)
'Discuss'. See above.
Format of answer. The wording suggests four parts: strengths of RP, weaknesses of RP, strengths of LS-B, weaknesses of LS-B. A paragraph or sub-section on each. With a fifth sub-section answering "When would each be appropriate?"
"When would each be appropriate?" This does not tell you 'discuss' etc. Rather, it is comes under the scope of the 'discuss' at the start. You should therefore discuss when each would be appropriate. Beware of little add-on parts to questions like this. Too many students ignore them, and lose important marks.
c) Discuss why the Client-Centred Approach is able to combine the strengths of both methods for building Expert Systems, and in what ways it can be better than either method. (30 marks)
'Discuss'. See above.
But note the emphasis on 'why'. The C-CA is something that was presented on the course. You are merely asked to discuss (reasons for and against, and implications) WHY it is able to ... and discuss in what ways ... Many students wasted time telling the examiner 'What' the steps of the C-CA are - which was not asked for. You should only explain 'what' in a 'discuss why' question if you need to do this for the purposes of telling why. Some students did not even attempt to 'discuss why'.
a) Explain the following techniques of knowledge acquisition and discuss when each might be used during a knowledge acquisition exercise, and why: i) Semi-structured interview ii) Books and papers iii) Role play (30 marks)
'Explain .. and discuss when .. '. Looks like I have to explain each (what and foundation) and then say when each should be used, and give reasons and implications of such use.
b) Explain what is meant by E (experience), U (understanding) and CPS (context-dependent problem solving) in the model of expertise presented on the course. Explain the relationship between them. (30 marks)
I am given what E, U and CPS stand for, and so should not waste my time telling examiner that. (Many did so.) However, I do need to say what each is, and what each is founded on. That includes saying what the characteristics of each is.
".. in the model of expertise presented on the course .." This tells me precisely what I am to talk aboot. I should not just talk about experience, understanding etc. in general terms. If I do, I am likely to lose marks, because the examiner will think I do not know the course work.
"Explain the relationship between them." Not only say what each is, but how they relate. Do not forget this part.
c) Explain how to overcome the problems of heuristics and describe a knowledge elicitation method for doing this. Illustrate the process from an example derived from your own experience. (Do NOT use the example given during the lectures.) (40 marks)
This has three parts:
'Explain'. This has been dealt with above. However, it would suggest that I should briefly state what I believe the problems of heuristics are, before I try to explain how to overcome them.
'Describe'. This means I just have to set out the method. I do not have to explain it in any depth, but just show that I know one that would be suitable. A method usually involves various steps. So I would set out the steps, and say what each is. However, the next part of the question tells me how much I need to say: namely, enough to allow me to illustrate the process.
'Illustrate'. This means that I must not just describe, explain or discuss in general terms, but must give an example. Many, many students forget, and omit the example, and so lose marks. I must think of an example that illustrates, in this case, the method that I have described above. If the question asks for an example or illustration, be sure to give one.
"(Do NOT use the example given during the lectures.)" This suggests that a method and an example to illustrate it were presented on the course. This can help me know which method the examiner is wanting, if I am not sure. Think back to the course. And, as I do so, I will probably remember a discussion of the problems of heuristics, which might help me answer the first part of part (c). How do I select my own example? Well, one thing that I should NOT do is to take the example given on the course and just modify it slightly; the examiner will see what I have done and take marks off. The examiner obviously wants me to take an effort to apply the course material in new ways. I must use my imagination.
So, you can see from the above, that the wording of exam questions can contain many hints and clues as to what is needed. I trust this discussion has been useful.
Last updated: 7 February 2001 email.