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%.