SEM540b
Graphics and Human-Computer Interaction.
Examination
January 1997.
2 hours.
ANSWER ALL
QUESTIONS.
1. Discuss
the importance of graphics standards (both ISO standards and the “de-facto
standards” imposed by manufacturers). To what extent is the ISO GKS standard
included in the graphics facilities offered in the system used for your
workshop ? (20%)
Describe
the GKS Cell-array primitive. (5%)
A
heraldry system includes the icons “lion” and “cross” defined as cell-array
primitives with the array values given below, in addition to many other such
icons. The system displays a shield on the screen with the appropriate
background colour or colours. The design must be mapped on to a square area 100
to 150 in x-coordinates and the same in y-coordinates.
The
first shield design has a golden lion on a red background filling the entire
area. The second design has a red cross on a silver background in the first and
third quarters and a golden lion on a blue background in the second and fourth
quarters. Explain how the GKS cell-array primitive, with suitable settings, may
be used to produce these outputs. (10%)
Array “lion” contains 0 0 0 0 0 1 0 0
0 1 1 0 0 0 1 0
0 1 1 1 1 1 1 0
0 0 1 1 1 1 1 0
0 1 0 1 0 1 1 0
0 1 0 1 0 1 1 0
0 0 0 0 0 0 0 0
and the array “cross” contains
0 0 0 0 0
0 0 1 0 0
0 1 1 1 0
0 0 1 0 0
0 0 0 0 0
2 (a)
Any succesful interface between human and computer has to find the common
ground between two systems which differ greatly in properties such as size and
speed. Describe the constraints imposed on
this interface by the limits of human perception and memory. (8%)
(b)
It has been decided that an annual questionnaire collecting feedback from
stuudents will be automated. Since student numbers are large and time is
limited, all available terminals must be used. Some are colour and others
monochrome, some have graphics and others only text, most have a full WIMP
interface but a few have only screen and keyboard. Assuming an identical
interface is required on every terminal in the system, identify the constraints
on this common interface. (7%)
(c)
The aim of the questionnaire is to carry out a comparative survey of the
lecture courses within the school as perceived by the students. It will cover
topics such as the content of the course and its relevance to the subject as a
whole, the standard of teaching and the availability of other resources needed
for this course. You may also include questions on additional aspects that you
consider important.
Give
a detailed description of the interface, remembering that it should be easy to
understand and use and must comply with the constraints identified in (a) and
(b).
(15%)
(d)
How would your design differ if you had a free choice of system on which to run
this questionnaire? (5%)
3. One
of the methods which attempt to make personal computer systems more “friendly”
is the provision of handwritten input. This software is a subset of the much
larger problem of handwriting recognition in general. Describe the main
difference between “on-line” and “off-line” handwriting recognition and explain
the effect this difference has on the resulting systems. (10%)
Describe
in detail a possible system for handwritten input using a tablet and stylus. Your
proposed system should consider the following questions:
Will your system recognise letters or words and how
will it do this?
Will it recognise cursive handwriting?
Can it be used by several different people or is it
restricted to just one user?
Normally the security of such systems is assured by
requiring a password to be entered at the start of each session. Is it
practical for your system to recognise a signature instead? (20%)
Resit Paper
for SEM540 January 1997.
3-hour joint
paper on:
INTRODUCTION
TO DATABASES
GRAPHICS AND
HUMAN-COMPUTER INTERACTION.
SEM540b Section should use the same questions and
require the student to answer 2 out of 3 questions.
The percentages should be scaled up to give each
question out of 50%.