Download Computing Science

[COMP(H)07]
NATIONAL
QUALIFICATIONS
2007
TIME: 2 HOURS 30
MINUTES
COMPUTING
HIGHER
Estimate Examination Paper
Attempt all questions in Section I.
Attempt all questions in Section II.
Attempt one sub-section in Section III
Part A
Part B
Part C
Artificial Intelligence
Computer Networking
Multimedia Technology
Page 8
Page 14
Page 18
Questions 20 to 26
Questions 27 to 30
Questions 31 to 34
For the sub-section chosen, attempt all questions.
Read all questions carefully.
Do not write on the question paper.
Write as neatly as possible.
This test paper must be withdrawn from candidates after the examination and any follow-up
discussion of marks/grades awarded. This is to ensure the ‘sight unseen’ status of this paper is
maintained for your centre and other schools/colleges during the diet of prelim examinations in
2006/2007. Submission of this test paper for Appeals purposes will assume that these conditions
have been applied.
© 2006-2007 Perfect Papers – All rights reserved.
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SECTION I
Attempt all questions in this section.
1.
Write the number -55 as an 8-bit binary number using two’s complement.
2.
Graphics can be represented as vectors or bit maps.
3.
4.
5.
6.
Marks
1
State two advantages of storing graphics as vectors and one advantage of storing graphics as bit
maps.
3
Describe the function of the data bus and what effects the data bus can have on the performance of a
computer system.
2
Julie has a 300 page document to print.
Which method of compensating for the differing speeds of processor and printer is more suitable for
this job? Explain your answer.
2
Describe the function of the disk defragmenter utility program and explain how it improves the
performance of a computer system.
2
A teacher wants to network four computers, one for each member of his department.
What would be the most suitable type of network in this situation? Explain your answer.
2
7.
Name two different network topologies and describe the consequences of a node failure in each.
3
8.
Name and describe two pieces of documentation that should come with a piece of software.
2
9.
The price of an item is calculated and stored as a variable itemprice.
(a)
(b)
10.
11.
Using code from a programming environment with which you are familiar, show how you
would display itemprice as pounds and pence.
3
What type of variable should itemprice be stored as?
1
Describe one difference between using an interpreter and a compiler to translate a HLL program in
terms of efficiency.
2
A program is written to store a list of house prices. An algorithm is used to find the number of houses
in the array that cost more than £100 000. Which standard algorithm should be used?
1
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SECTION I (continued)
Marks
12.
13.
Scripting languages are often used to create macros.
(a)
What is a macro?
1
(b)
Describe how a scripting language differs from a procedural language
2
State and describe three ways in which a piece of software can be evaluated.
3
(30)
[END OF SECTION 1]
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SECTION II
Attempt all questions in this section.
14.
Marks
Julie wants to purchase a digital camera.
(a)
The specifications for two cameras are shown below.
•
•
•
•
•
•
•
(b)
(c)
NicePix 2000
5.0 million pixels
2.8x optical zoom (equiv. 38106 mm)
Bright Lens 1:3.0 (wide) - 5.0
(tele)
Super macro mode up to 2 cm
(wide)
28MB internal memory
5 Scene modes
Movie recording function (up to
memory card's capacity)
•
•
•
•
•
•
•
Halcian 4
4.0 megapixels
Compact size and lightweight body
3x optical zoom lens, covering the
key photographic range of 38 to
114mm (35mm equivalent)
2.0" LCD monitor simplifies
composition and playback
D-Lighting provides a powerful incamera solution to repair and restore
underexposed images
In-Camera Red-Eye Fix
Face-priority AF automatically
locates and focuses on people's faces
ensuring superb, crisply focused
portraits
Which camera should Julie purchase? Give two reasons for your answer.
2
Julie sees that most cameras use compact flash cards to store the pictures. Describe two
advantages of using compact flash cards.
2
Julie takes a picture that is stored as a bit mapped image. The image is 1024 by 768 pixels with
a bit-depth of 24.
(d)
(i)
Apart from file size, what effect does the bit-depth of an image have?
1
(ii)
Calculate the file size of the image. Show all working and express your answer in
appropriate units.
3
Julie also uses a scanner to import pictures into her computer. The scanner is connected to her
computer via a USB interface. Describe two functions of the interface and how they would be
used in this situation.
4
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SECTION II (continued)
Marks
15.
A computer has a 24-bit data bus and a 32-bit address bus.
(a)
Calculate the maximum amount of memory that could be addressed by this computer. Express
your answer using suitable units.
3
(b)
Describe two types of read only memory.
2
(c)
Describe how a processor would carry out a memory read operation. Your answer should
mention the buses and registers used at each stage.
4
State the function of two of the lines on the control bus and explain their purpose.
2
(d)
16.
Kat is using her computer to word process a report.
(a)
(b)
(c)
Kat stores her report on the hard disk of her computer system. Describe how the following
functions of the operating system would be involved in this process.
(i)
Memory management
1
(ii)
File management
1
(iii) Resource allocation
1
Kat is very concerned that her computer could be infected by a virus or a trojan horse. Explain
the difference between these.
2
Kat purchases anti-virus detection software. Describe two features of her computer system that
KAT should check to ensure that the software is compatible with it.
2
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SECTION II (continued)
Marks
17.
A school requires a piece of software to be created that stores the names and grades of all pupils in
arrays and is able to find the highest and lowest average grades.
(NOTE: Grades are numbers between 1 and 7)
(a)
(b)
A systems analysis is carried out at the start of the process. Describe the document that is
produced at the end of this process.
A design is produced to solve the problem and is shown below.
1.
2.
3.
4.
5.
18.
Initialise Variables
Enter pupils names and grades
Find highest grade
Find lowest grade
Display results
(i)
Name the design methodology shown above.
1
(ii)
Step 3 uses the parameters grade and highest_grade. State the data types of these
parameters and whether they should called by reference or by value.
4
Using a methodology you are familiar with, refine step 3.
6
(iii)
(c)
2
The programmer makes use of a module library when implementing the program design.
(i)
What is a module library?
1
(ii)
Describe two advantages to the programmer of using a module library for this task.
2
A company has just upgraded the operating system on their computer network.
(a)
(b)
(c)
What type of maintenance may have to be carried out on the company’s computer software?
Give a reason for your answer.
1
Describe the other two types of maintenance that can be carried out on software and describe a
situation where they may be required.
3
Describe what a programmer can do to make a program more maintainable.
1
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SECTION II (continued)
Marks
19.
A hospital uses a computer program to record five readings of the pulse rates of a patient during a
day. These readings are then used to get an average reading for the day. These pulse rates should
range from 60 to 120 beats per minute.
(a)
Three different types of test data should be used to ensure that a program works correctly.
Describe each of these types of test data.
3
(b)
For each type of test data described in part (a), give a set of data for the program.
3
(c)
Describe exhaustive testing and state why it would not be possible to exhaustively test this
program.
2
Describe the process of acceptance testing.
1
(d)
(60)
[END OF SECTION II]
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SECTION III
Marks
Part A – Artificial Intelligence
Attempt all questions.
20.
21.
Much research is being carried out in the area of artificial intelligence.
(a)
What is meant by the term artificial intelligence?
1
(b)
Justify why the following aspects of human behaviour are considered to be intelligent:
(i)
Cognitive ability
1
(ii)
Creativity
1
A computer vision system is being developed to assist with spacecraft docking. It is intended that one
or more TV cameras mounted on one spacecraft will view the other craft during approach. A
computer will process the digitised images to obtain information at each stage about whether the two
vehicles are aligned and positioned correctly and approaching at the right speed.
The stages involved in any computer vision system can be represented by the diagram below.
Image
Acquisition
(a)
(b)
Signal
Processing
Edge
Detection
Object
Recognition
Image
Understanding
Explain the need for data compression in the signal processing stage of the spacecraft docking
vision system.
2
Object recognition in the vision system that is being developed for the spacecraft docking
system makes use of an artificial neural system (ANS).
(i)
Explain how an artificial neural network would be used to assist in object recognition.
(ii)
The ANS being used in the spacecraft docking system is an example of a software
model rather than a hard-wired model. Explain why this is the case.
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SECTION III
Marks
Part A – Artificial Intelligence (continued)
22.
Programs such as Deep Blue, the chess playing software developed by IBM, have demonstrated that it
is possible to develop game playing programs that exhibit intelligence.
(a)
(i)
Name one other game playing program that has successfully exhibited intelligence.
(ii)
Explain the success of these and other successful game playing programs.
(b)
Explain the failure of game playing programs such as Backgammon and Scrabble.
(c)
Many successful examples of game playing programs make use of search techniques.
(i)
3
2
Compare a breadth-first search with a depth-first search in terms of:
• the order of visiting nodes
• memory implications
Your answer should refer to the following search tree.
D
J
A
H
E
(d)
X
C
Q
F
L
M
G
S
R
N
B
W
P
I
(ii)
Explain the need for heuristics in successful game playing programs.
(iii)
Give one example of a heuristic that could be used in the game of X’s and O’s.
7
Explain the effect that the development of faster processors and increased memory has had on
the development of successful game playing programs.
2
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SECTION III
Marks
Part A – Artificial Intelligence (continued)
23.
The SHRDLU program was designed to allow the user to communicate in English and manipulate
coloured building blocks. The program made use of natural language processing techniques.
(a)
Explain the success of the SHRDLU program’s ability to interact in English with the user.
(b)
The ScotWest Newspaper Group has developed a natural language search engine for its Web
site. The SCOTTIE search engine allows users to enter query sentences in English and then
search its database of previous articles to find matches for the user criteria. A sample screen
from the SCOTTIE Web site is shown below.
2
Welcome to SCOTTIE, the search engine of the ScotWest Newspaper Group
Enter your query
When did Jack McConnell first enter politics?
Click to search our database of previous articles
SEARC
H
(i)
Explain the role of the independent test group during the development of the SCOTTIE
search engine.
(ii)
Explain two difficulties associated with the development of a natural language
interface for a search engine such as the one described above.
(iii)
Describe one application of natural language processing that could be used to extend
the natural language interface described above. You should justify your answer by
explaining how this application would enhance the current natural language interface
of the SCOTTIE search engine.
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SECTION III
Marks
Part A – Artificial Intelligence (continued)
24.
A development company has produced an expert system for a garden centre. The ERIK expert system
will be available for customers of the garden centre to consult at any time. It provides advice about
soil conditions and suggests plants that are suitable for the soil. The user interface of the expert
system includes an explanation and justification facility.
(a)
(b)
(c)
(d)
Justify the inclusion of an explanation and justification facility in the ERIK expert system
described above.
2
Although the ERIK expert system was costly to develop, it is hoped that it will bring several
benefits for the garden centre and the staff.
Suggest one possible benefit for the garden centre staff that could result from the development
of the ERIK expert system. Justify your answer.
1
Explain the need for a limited domain in an expert system and suggest a suitable domain for
the ERIK expert system.
2
A customer visiting the garden centre uses the ERIK expert system and buys several of the
plants that ERIK recommends for his soil type. It is later discovered, that the ERIK expert
system had been giving bad advice. The garden centre refunds all customers affected by the
bad advice and makes a claim against the development company.
(i)
Suggest one possible reason for the claim against the development company being
justified.
(ii)
Identify the type of maintenance that would be required to remove the source of the
bad advice.
2
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SECTION III
Marks
Part A – Artificial Intelligence (continued)
25.
Artificial intelligence researchers have been trying for over thirty years to create intelligent robots.
Although progress has been made in some areas, we are still a long way from the intelligent robots
that we often see in science fiction.
(a)
(b)
(i)
Explain the difficulties faced by researchers and developers of intelligent robots in
terms of processor power and navigation
(ii)
Suggest solutions to each of the difficulties you mentioned in part (i) above.
4
Many modern cars provide parking assistance as an embedded system. When activated by the
car driver, the parking assistance system first determines if there is enough room in the parking
space to park the car. If there is enough space, the system then helps the driver manoeuvre into
the parking space.
(i)
Describe one benefit of using embedded technology in a parking assistance system.
(ii)
Is the embedded parking assistance system an example of an intelligent robot? Explain
your answer.
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SECTION III
Marks
Part A – Artificial Intelligence (continued)
26.
A knowledge base contains facts and rules about flights available with a low cost carrier.
(a)
1
direct(edinburgh, paris).
2
3
4
5
6
7
8
9
10
direct(edinburgh, rome).
direct(glasgow, palma).
direct(glasgow, vienna).
direct(paris, salzburg).
direct(paris, nice).
direct(rome, turin).
direct(vienna, berlin).
direct(vienna, salzburg).
can_fly(X,Y) if
direct(X, Z) and
direct(Z, Y).
(i)
There is a direct flight from Edinburgh to
Paris.
It is possible to fly from X to Y if there is a
direct flight from X to Z and also a direct
flight from Z to Y.
Assuming a depth-first search is used, explain how the program would find the first
solution to the following query. You should use the line numbers to exemplify your
answer.
? can_fly(glasgow, X)
(ii)
(b)
Explain the use made of instantiation by the program when searching for the solution
to the query in part (i) above.
5
What would be the solution to the following query?
? can_fly(edinburgh, X) and not can_fly(glasgow, X)
2
(50)
[END OF SECTION III – PART A]
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SECTION III
Marks
Part B – Computer Networking
Attempt all questions.
27.
Below is a sample of XHTML coding.
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html
PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en"
lang="en">
<meta name="keywords" content="nouvelle, hotel, holiday, rooms,
resort, business, accommodation" />
<meta name="description" content="Room details and booking for
the Nouvelle Hotel" />
<head>
<title> Nouvelle Hotel </title>
</head>
<body>
<p>
Please choose a room type:
<br /><br />
<select name="room">
<option selected="selected">Single</option>
<option>Twin</option>
<option>Double</option>
</select>
</p>
</body>
</html>
(a)
With reference to the coding above, give two examples of where HTML may differ from
XHTML.
2
(b)
State the type of language that is shown above. Give a reason for your answer.
2
(c)
Users of mobile telephones and PDAs are now able to access pages of information through
their telecommunications provider.
(d)
(i)
Explain why the HTTP protocol is unsuitable for use with such devices.
1
(ii)
With this in mind, explain how pages from sites such as Google and BBC News are able
to be viewed.
2
Most major organisations ensure the their websites adopt a corporate identity, where each page
in the site maintains the same look and feel. Name and describe one method of ensuring each
page in the site adheres to the same format.
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SECTION III
Marks
Part B – Computing Networking (continued)
28.
Anthony has just set up a business based in the UK which offers online support to people with
computer problems. He has called his company Let Us Help, and wants to use www.letushelp as the
initial part of his URL.
(a)
Suggest a suitable domain name suffix and give a reason for your answer.
2
(b)
Describe two different types of search engine and explain how Anthony can expect his website
address to appear on their listings.
4
When a user enters the full URL of Anthony’s website into their browser, how does it match
this to an IP address?
2
When Anthony connects to his Internet Service Provider, he is allocated a static IP address.
Give one advantage and one disadvantage of having a static IP address as opposed to a
dynamic one.
2
The number of IP addresses available for use on the internet are predicted to run out. Describe
one proposal to solve this problem.
1
(f)
Explain the difference between an IP address and a MAC address.
1
(g)
Anthony wants his clients to be able to pay for their support through his website. How could
he reassure his customers that it would be safe for them to do this?
2
(c)
(d)
(e)
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SECTION III
Marks
Part B – Computing Networking (continued)
29.
A medical practice has installed a local area network in its offices. There are 18 computers on the
network in a building consisting of three floors of 6 offices.
(a)
(b)
The computers are connected using 100BaseTX Category 5 cable.
(i)
What speed of data transmission is this designed to operate at?
1
(ii)
What is the maximum distance for a segment of 100BaseTX Category 5 cable?
1
(iii)
What could be done to connect computers where this may be insufficient?
1
One of the doctor’s claims that that the network is faster when he starts work early in the
morning than it is throughout the day. With reference to CSMA/CD, explain how the amount
of traffic can reduce the network performance.
3
(c)
Which layer of the OSI model does CSMA/CD operate at?
1
(d)
Explain the purpose of the Application Layer.
2
(e)
The practice’s telephone system has been set up for Voice over IP (VOIP).
(f)
(g)
(h)
(i)
What is Voice over IP?
1
(ii)
Give two benefits to a company making use of such a system.
2
The company has a second practice located in a listed building. Legislation prevents them
from running cables through the walls. State two items of hardware required to provide them
with a wireless local area network and describe their function.
2
Staff are aware that some networks are open to other computers within range. Explain two
ways in which the surgery could ensure their wireless network is secure from such a threat.
2
Some of the doctors make use of Bluetooth to allow their Personal Digital Assistants to
transfer data between their computer and hand held device. Outline two differences between a
Wireless Local Area Network (WLAN) and a Wireless Personal Area Network (WPAN).
2
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Marks
Part B – Computing Networking (continued)
30.
(a)
(b)
A finance company has recently suffered a denial of service attack by exploiting a flaw in
software. How could the company reduce the risk of this occurring in the future.
Most organisations have recovery strategies in the event of data loss.
(i)
(ii)
(c)
Give an example of a software solution which could minimise the impact of such a
disaster.
1
Give an example of a hardware strategy to prevent loss of data.
1
The company use a proxy server to connect to the internet. Explain how Network Address
Translation can help with their network security.
(d)
1
The company have internet access across their network, but are concerned about possible
misuse by its employees. Give three steps the company could take to ensure staff are using
the resource properly.
2
3
(50)
[END OF SECTION III – PART B]
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SECTION III
Marks
Part C – Multimedia Technology
Attempt all questions.
31.
A multimedia product is being developed to support language students in their learning of the
vocabulary and the grammar of the language they are studying. The product will be delivered using
CD-ROMs and via a web-site where access will be restricted to those who have bought an annual
licence.
(a)
(b)
The development of the product involves the stages of analysis and design.
(i)
State the purpose of the analysis stage in the development of a multimedia product.
1
(ii)
Describe one technique that is used at the design stage of the development process for a
multimedia product.
2
A multimedia authoring tool is used to develop the product.
Describe two functions of the multimedia authoring tool that make it the suitable development
tool during this project.
(c)
2
Several movie clips have to be placed in a suitable order to make the progress of content for
each lesson appropriate.
Suggest one function of video editing software that would be used in this case,
supporting your choice with one reason.
(d)
2
During the development of the product the error message ‘no suitable codec available’ is
shown when the video file is played.
(i)
Explain the role of a ‘codec’.
1
(ii)
Describe one suitable codec that may allow the video to be played back in this
instance.
2
Describe the role of the graphics card in the playback of the video.
2
(iii)
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Part C– Multimedia Technology (continued)
32.
Matthew is creating a web-site for the East of Scotland Air Show. The web-site has a display of last
years show and information about this years show.
(a)
Matthew used a digital camera to capture the images from last years show
(i)
Describe how a digital camera captures and stores data.
(ii)
The digital camera may store the image as a jpeg or a tiff file format.
3
Recommend which file format Matthew should use to save the images to be used on
the web-site.
2
(b) Matthew uses an image editing program to increase the resolution of the images he has
captured.
(i)
(ii)
Re-sampling is one technique that may used to allow the resolution of the image to be
increased.
Explain the term re-sampling.
2
State one problem with the technique that you have chosen.
1
(c) Matthew adds text to his page and has to decide whether to anti-alias the font used or not. He
uses a font size of 12 for his text.
Recommend whether you feel Matthew should use anti-aliasing or not.
3
(d) Matthew is scanning a 5 inches by 4 inches as a 24-bit bit-map image. He scans the image at
72dpi.
Calculate the storage requirements for this scanning resolution of 72dpi
3
(e) Matthew knows that users will be viewing the web-site via dial-up, broadband and wireless
connections. He decides to use to select the interlacing option when saving the images.
Explain which user type will benefit most from the use of interlacing images, giving one
reason why.
2
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Part C– Multimedia Technology (continued)
33.
Jimmy has owned a Wakasaki motorcycle for many years and decides to create a web-site to promote
the motor cycle. He wants to show highlights of the many events that are organised by members of
the Wakasaki motorcycle club and to promote future events.
(a)
Jimmy has to decide between using a WYSIWYG editor or a text editor. He is relatively new
to creating web-sites but has created a couple for his family before.
Suggest which editor Jimmy should use, giving two supporting reasons.
(b)
Jimmy records a 2 minute recording of himself giving a brief history of the Wakasaki motor
bike.
(i)
Describe the role of the sound card in the capture of Jimmy’s voice.
(ii)
Jimmy’s voice may be recorded in a file format that is either a RAW or a RIFF.
Recommend which file format would be most suitable for Jimmy’s web-site.
(c)
(i)
(ii)
2
2
Jimmy has a stereo 2 minute sound file that plays when the web-site is accessed. The
sound file is sampled at 22.1Khz.
If the file is 10.12 Megabytes, what is the sampling depth in bytes?
3
The sound file seems to be louder than other music and narrations that are used on the
web-site.
Describe one technique that may be used to allow all music and sounds to appear at an
even volume.
(d)
2
2
Jimmy gets a friend to add an SVG image to his website.
(i)
(ii)
Why in this situation is the use of an SVG image better than using a bit-map for
Jimmy?
2
The SVG image contains a rectangle.
What is the basic format of a rectangle in SVG?
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Part C– Multimedia Technology (continued)
34.
The management of Edinbello Castle have decided to create an interactive web-site that
allows users to view details on the castle.
(a)
A 24-bit bit map image is created and a compression
algorithm is applied to it.
Describe one suitable technique for compressing an
image similar to the one shown.
2
(b)
Part of the web-site has video showing the internal rooms of the castle.
The developers have to decide whether to allow the users to download the videos or to
stream the video to the user’s machine.
Recommend either downloading or streaming as a suitable technique.
Your answer should to:
• Copyright issues
• Download times
• Comparison of broadband, wireless and dial-up connections
(c)
The management of Edinbello Castle have the choice of adding background music as a
MIDI file or MP3.
Which of MIDI or MP3 would you recommend be used, giving one supporting
statement.
[END OF SECTION III – PART C]
[END OF QUESTION PAPER]
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1
(50)