BIS2040 final session: Revision and exam preparation.

BIS2040 final session:Revision and exam

preparation

The exam

A two hour paper Five questions on the paper You will choose three out of the five Expect each question to have several

parts - usually (a), (b) & ( c) There won’t be any questions on neural

nets

Exam technique

Don’t be tempted to do less than three questions However well you do on the questions you

attempt, you’ll lose more marks than you could have gained by doing a third question

Exam technique

Don’t be tempted to do more than three questions If you do, the marker will simply ignore your

last answer So your last answer would be a complete

waste of time and effort

Exam technique

Try to write something on each part of the questions that you choose

The marks beside each part of the question are a guide as to how much time it’s worth spending on that part of the question.

Exam technique

You should pick your questions carefully, avoiding any that look hard All the questions carry equal marks, so

there’s no advantage to picking a hard question.

Exam technique

You should spend about 35 minutes on each question. This gives you 5 minutes choosing time at

the start, and 10 minutes finishing-off time at the end.

Exam technique

You need to be quite sure you grasp what a question is about, before you start to answer it.

Subject matter

The exam will cover topics that have been covered in the lectures

Not Kappa-PC - that was covered by the coursework, and won’t be in the exam

Subject matter

The material in the Module Handbook should be enough to cover any of the answers to any of the questions

If you go beyond the material in the handbook, using other material that you’ve read, that’s fine, and liable to get you extra marks.

Exam technique

Sometimes a student reads the question, and remembers something that sounds vaguely similar, and writes about that.

If the question says “describe the techniques of knowledge elicitation” and you write about the techniques of knowledge representation, you won’t get any marks.

Major themes in the course

The nature of knowledge-based systems and of skill, and expertise and experts Expert systems: advantages and risks

The architecture of expert systems their reasoning mechanisms other features that make them work


The various different forms of knowledge representation logic rules (rules are particularly important) semantic nets frames

Case-based reasoning what it is how it differs from rule-based reasoning


Knowledge acquisition how it’s done why it’s difficult what the techniques are

Neural networks what they consist of what they’re good for what they can and can’t do

Examples of expert systems

Exam strategy

The pattern in recent exams has been that there has been a whole exam question devoted to each of the following topics: case-based reasoning knowledge elicitation knowledge representation using rules knowledge representation using other things the nature & architecture of KBS

Exam strategy

This suggests that you don’t need to learn the whole syllabus.

You could just pick certain lectures, covering certain topics, and thoroughly master the content of them so that you feel reasonably confident of answering likely questions in that field.

You could just pick three topics (which is risky) or four topics (which is safer).


The nature of knowledge-based systems and of skill, and

expertise and experts Expert systems:

advantages and risks


The nature of knowledge-based systems and of skill, and

expertise and experts Expert systems:

advantages and risks

The sort of answer that is required:Short written pieces, explaining concepts, or explaining how and why things are done the way they are in the expert systems business.Chapter 1 material, and “distinctive features” from chapter 3.


The architecture of expert systems their reasoning

mechanisms other features that

make them work


The architecture of expert systems their reasoning

mechanisms other features that

make them work

Could be part of a question - unlikely to be more.

The sort of answer that is required:

Short written pieces, explaining concepts, or diagrams.


The various different forms of knowledge representation rules (rules are

particularly important)


The various different forms of knowledge representation rules (rules are

particularly important)

Expect a whole question on rule-based reasoning.


Short written pieces, explaining concepts. Likely to be at least one “skills” part.

Chapter 2 & chap. 3 material.


The various different forms of knowledge representation logic semantic nets frames


The various different forms of knowledge representation logic semantic nets frames

Expect a whole question on non-rule-based knowledge representation.


Mostly “skills” answers -short written pieces are rare in this section.

Chapter 4 material.


Case-based reasoning what it is how it works how it differs

from rule-based reasoning


Case-based reasoning what it is how it works how it differs

from rule-based reasoning

Expect a whole question on case-based reasoning.


Short written pieces, explaining concepts. Alternatively, short case histories.

Chapter 9 material.


Knowledge acquisition how it’s done why it’s difficult what the

techniques are


Knowledge acquisition how it’s done why it’s difficult what the

techniques are

Expect a large part of a question on knowledge acquisition. Related topics, like system development & e.s. shells, might provide the other parts. The sort of answer that is required:Short written pieces, explaining concepts. Chapter 6, 7 & 8 material.





Not likely to be given a question on its own.

If it appears at all, likely to be part of another question.


Short case histories or comparisons

Chapter 5 & chap.9 material.


Neural networks what they consist of what they’re good for what they can and

can’t do


Neural networks what they consist of what they’re good for what they can and

can’t do} But this

won’t be in the exam

“skill” questions

Skill 1: the “draw up a frame system” question

Question:

A colour scientist is interviewed. Part of the interview transcript reads as follows:


"We can think of colours as warm colours, cold colours and pseudo colours. Warm colours include reds and yellows. Cold colours include greens and blues. Magentas are pseudo colours. Actually, it's probably best to think of warm colours and cold colours as different sorts of true colour, as opposed to pseudo colours.


"Every colour has a saturation and a luminosity. And every colour has two CIE coordinates: x and y - they're numbers, between zero and one. Every true colour has a dominant wavelength.


"For example, this is a green: it's called Wratten 58 Green. Its dominant wavelength is 540.3 nanometres, its saturation is 86.2%, its luminosity is 23.7%, its CIE coordinates are X = 0.24 and Y = 0.70. What about white? Well, I suppose I'd call that a pseudo colour, because it hasn't got a dominant wavelength. Its CIE coordinates are 0.33 and 0.33."


Provide a description of a frame system which represents this information.


What’s it all about?


What’s it all about?

Colours.

Therefore all the frames in this system will be types of colour, or examples of colour.


What types of colour, and what examples of colours, are mentioned?


What types of colour, and what examples of colours, are mentioned?

Types: warm, cold, pseudo, reds, yellows, greens,

blues, magentas, true, whites

Examples: Wratten 58 Green

- each of these will be a frame in its own right.


What are the qualities that describe all colours?


What are the qualities that describe all colours?

Saturation, luminosity, CIE coordinate X, CIE coordinate Y

- each of these will be a slot in the top-level frame “colours”

- the value, in each case, will be “?”,

meaning “it’s different for every colour, so you really can’t say what it is for colours in general”


Are there any other qualities that describe some, but not all, of the colours?


Are there any other qualities that describe some, but not all, of the colours?

Yes - dominant wavelength

- This will be a slot in the frame “true colour”. Its value will be “?”.


Are any restrictions on permitted values mentioned?


Are any restrictions on permitted values mentioned?

Yes - a CIE coordinate X has to be a number greater than 0 and less than 1, and so does a CIE coordinate Y.


What are the subclass_of relations for all the frames we listed earlier?


What are the subclass_of relations for all the frames we listed earlier?

“...warm colours and cold colours [are] different sorts of true colour…”

“...Warm colours include reds and yellows. Cold colours include greens and blues. Magentas are pseudo colours. …”

etc


Listing all these relationships, we have: warm colour is a subclass of true colour cold colour is a subclass of true colour pseudo colour is a subclass of colour reds is a subclass of warm colour yellows is a subclass of warm colour greens is a subclass of cold colour blues is a subclass of cold colour magentas is a subclass of pseudo colour true is a subclass of colour whites is a subclass of pseudo colour


and: Wratten 58 Green is an instance of green


Putting this all together, we have the following frames:

Name: colour Subclass_of: thing Slots:

Name: Value: Restrictions:saturation ?Luminosity ?CIE coordinate X ? >0, <1 CIE coordinate Y ? >0, <1


Name: true colour Subclass_of: colour Slots:

Name: Value: Restrictions:dominant wavelength ?


Name: pseudo colour Subclass_of: colour

Name: warm colour Subclass_of: true colour

Name: cold colour Subclass_of: true colour

Name: magenta Subclass_of: pseudo colour


Name: red Subclass_of: warm colour

Name: yellow Subclass_of: warm colour

Name: green Subclass_of: cold colour

Name: blue Subclass_of: cold colour


Name: white Subclass_of: pseudo colour Slots:

Name: Value: Restrictions:CIE coordinate X 0.33CIE coordinate Y 0.33


Name: Wratten 58 Green Instance_of: green Slots:

Name: Value: Restrictions:saturation 86.2%luminosity 23.7%CIE coordinate X 0.33CIE coordinate Y 0.33dominant wavelength 540.3 nm

Skill 2: the “draw up a semantic net ” question

Question

Draw a semantic net which expresses the information in the following piece of text:


“Turning to Nabisco, Nabisco is a biscuit company operating in the UK. Like other food companies, biscuit companies have to meet stringent quality standards. Nabisco has three major competitors. Among other things, Nabisco makes cookies, and cookies are a specialised product sold to select consumer groups.”


Step 1 - locate the things:

































Step 2 - locate the relationships:


















Step 2 - locate the relationships:“Turning to Nabisco, Nabisco is a biscuit company operating in the UK. Like other food companies, biscuit companies have to meet stringent quality standards. Nabisco has three major competitors. Among other things, Nabisco makes cookies, and cookies are a specialised product sold to select consumer groups.”

Nabiscooperates_inUKFood companyhave_to_meetstringent quality standardsNabiscomakescookieSpecialised productsold_toselect consumer group


Step 2 - locate the relationships:“Turning to Nabisco, Nabisco is a biscuit company operating in the UK. Like other food companies, biscuit companies have to meet stringent quality standards. Nabisco has three major competitors. Among other things, Nabisco makes cookies, and cookies are a specialised product sold to select consumer groups.”

Nabiscooperates_inUKFood companyhave_to_meetstringent quality standardsNabiscomakescookieSpecialised productsold_toselect consumer group

major_competitor1

Nabisco has major_competitor2

major_competitor3


Step 3 - locate the implied relationships:





Nabisco instance of biscuit company




biscuit companyis afood company




cookieis aspecialised product


You’re now in a position to draw the diagram. Each of the “things” is given its own box, and written in:

NabiscoNabisco

Stringent quality

standards

Cookie UK

Major competitor 1

Major competitor 2

Major competitor 3

Select consumer

group

Specialised product

Food company

Biscuit company


The boxes are joined together using arrows - it’s important the the arrows point in the right direction. If a biscuit company is a food company. Then the arrow that will be called “isa” points from biscuit company to food company.

NabiscoNabisco

Stringent quality

standards

Cookie UK

Major competitor 1

Major competitor 2

Major competitor 3

Select consumer

group

Specialised product

Food company

Biscuit company


Finally, each arrow is given an appropriate label:

NabiscoNabisco

Stringent quality

standard

Cookie UK

Major competitor 1

Major competitor 2

Major competitor 3

Select consumer

group

Specialised product

Food company

Biscuit company

isa

isa

instance_of

operating_in

makes

has_to_meet

sold_to

has

has

has

Skill 3: the “draw up an and-or chart ” question

Question

Here are some rules describing the macroeconomic functioning of the British economy. Draw an and-or chart representing this information.

If exports decrease or imports increase or public spending increases, then the budget needs more money.

If production decreases, then exports decrease.

If workers’ incentives decrease then production decreases.

If taxes increase or real wages decrease then workers’ incentives decrease .

If import prices decrease then imports increase.

If the pound rises then import prices decrease.

If the housing shortage increases or real rates decrease then public spending increases.


Step 1: decide what the ultimate conclusion (the final piece of advice) is.

This may be obvious. If it isn’t obvious, the task is to find a rule

whose conclusion isn’t the condition for any of the other rules.

In this case, it’s this one:

If exports decrease or imports increase or public spending increases, then the budget needs more money.


If workers’ incentives decrease then production decreases.

If taxes increase or real wages decrease then workers’ incentives decrease .

If import prices decrease then imports increase.

If the pound rises then import prices decrease.

If the housing shortage increases or real rates decrease then public spending increases.


The conclusion that you’ve just located belongs in a box at the top of your diagram.

The conditions of this rule each go into a box immediately below the top box in the diagram.


The budget needs more money

Exports decrease

Imports increase

Public spending increases


Notice that, because the conditions had the word “or” between them, the lines leading down to the next row of boxes aren’t connected by an arc.

If the conditions had had the word “and” between them, the lines would have been connected by an arc.


From now on, it’s a question of extending the diagram downwards.

If any on the boxes in the bottom row is the conclusion of another rule, follow the same procedure to draw some boxes underneath it.


For instance, there is a box in the bottom row like this:

Is there a rule that has this as its conclusion? Yes:


So the box gets another

box underneath it:

Exports decrease

Exports decrease

Production decreases


For instance, there is a box in the bottom row like this:

Is there a rule that has this as its conclusion? Yes: If the housing shortage increases or real rates

decrease then public spending increases.

So the box gets another 2 boxes underneath it:



Housing shortage increases

Real rates decrease


Repeat this until you’ve covered all the rules that you were given.

It’s a good idea to cross out each rule as you deal with it. When all the rules are crossed out, the diagram should be complete.

Skill 4: the “turn this logic statement into English”

question

You need to know what the logic symbols mean:

means “and”

means “or”

means “if … then ...”

means “… if and only if ...”

means “not”


question

You need to know that a predicate adds a quality to an item, or specifies a relationship between two (or more) items)

If H stands for “happy” and A stands for “Andy”, thenH(A) stands for “Andy is happy”

If L stands for “loves” and B stands for “Beth”, then L(A,B) stands for “Andy loves Beth”.


question

You need to realise that a letter inside the brackets of a predicate may well be a variable, standing for something vague like “something”.


question

Provided you know all this, this sort of question is easy.

You just write a framework for the logic connective, and slot phrases representing the predicates into it.


question

If H stands for “happy” and A stands for “Andy”, and B stands for “Beth”, L stands for “loves” and R stands for “rich”, and C stands for “clever”, what does

R(A) C(B) L(B, A) stand for?The logic symbols tell you that it will beif… and … then …The predicates tell you what to put into the gaps:if Andy is rich and Beth is clever then Beth loves

Andy.

BIS2040 final session: Revision and exam preparation.

Documents

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