1. HCI

2. What is HCI?
Human Computer Interaction is a term used to describe the interaction between a user and a computer.
‘Computer’ is not just the PC, but also machines like cash points, photocopiers or even a jumbo jet

3. Nature of HCI HCI Ergonomics & Human Factors Cognitive Psychology
Engineering
Social &
Organisational
Psychology
HCI
Design
Computer
Science
Soft
sciences
Artificial
Intelligence
Linguistics

4. The Importance Of HCI Safely - a jumbo jet pilot Effectively
A good design can ensure users carry out their tasks
Safely - a jumbo jet pilot
Effectively
users do not video the wrong side
Efficiently
Users do not spend 5 minutes trying to find the correct way to insert a cash card
Well-designed systems can improve the output of employees
Enjoyably -a child learning mathematics

5. Consequences of poor interface design
User frustration
Low productivity
Stress
Under-utilisation of system
Increased mistakes in data entry
Poor volume of throughput

6. Designing Useable Systems
Who will use the system
What tasks they will be doing
The environment
What is technologically feasible?

7. Colour
Colour is very effective for highlighting, but must be used carefully.
Colours have a meaning
Red - danger / warmth
Green – normality
Blue – cold
Colour can be used to make things easier to spot, such as when you are overdrawn.

8. Colour and Design Use background colours carefully
The screen should not contain too much bright colour.
Don’t use too many colours on one screen
do not exceed 6 different colours
Be consistent across the whole system
one colour should not be used for more than one purpose.

9. Colour Hints
Colours which clash should be avoided e.g. purple with pink.
Care should be taken as 8% of men and 0.4% of women are colour blind, and have difficulty with colours such as green, red, and yellow.

10. Colour Hints (Cont)
Colour can be used to convey greater amounts of information more clearly e.g. air traffic control
Colour should be used to improve user performance
Colour and brightness effect perceived size. Warm colours are larger (red, yellow). Cold colours are smaller (blue, green).

11. Avoid text over pictures
Bright Clashing Colours
Colours with insufficient contrast should be avoided e.g. yellow and white
Avoid text over pictures

12. Presentation And Contrast
Positive presentation is when the background is fairly subdued, i.e. white background, dark text
Negative presentation – dark background, white text.
A bright area on a dark background seems larger than the reverse.
Which is best???

13. Other Factors
Take care in spacing fonts, and choosing a correct font for screen use.
Letter Spacing
|3 looks like a B. Space it out | 3
Some fonts can be difficult to read, and should be avoided.
You must be careful how you word things, so that they are not misinterpreted. – different words can mean different things for different cultures / countries
Consider the lighting – Different levels of light can affect the colours seen

14. Microsoft Access And HCI
Form Design
Report Design
AutoExec Macros
Autonumbers on forms
Course 2 forms

15. Memory Capacity Modality Permanency STM : Miller’s magic rule (7 + -2)
LTM : infinity?
Modality
STM : Acoustic, visual
LTM : Semantic
Permanency
STM : decays
LTM : permanent

16. Aardvark
Cat
Dog
Turtle
Snake
London
Bristol
Robbie Williams
Test
George
Tony
Human
Alien
Outline
Enrol
Student

17. Memory Primacy and recent effect Minimise distraction during tasks
Do not overload STM
Increase structuring of information
Be consistent.
Images are helpful when accompanied by text
Avoid similar sounding names
Material is far more easily recognised than recalled

18. Remember? Aardvark Cat Dog Turtle Snake London Bristol Robbie Williams
How many words?
Aardvark
Cat
Dog
Turtle
Snake
London
Bristol
Robbie Williams
Test
George
Tony
Human
Alien
Outline
Enrol
Student

19. Design Principles Useable Internally Transparent to the User
Autoexec macro
Guidance not control
Predictability
Reversibility
Consistency
Reduces learning load
Increases recognition
User Friendly
1.      Easy to start
2.      Self-contained,
3.      Quick access.
4.      Always appear friendly to the user.
5.      The user should know what to do and when to do it, why they are doing it, and how they do it at every stage.
6.      Minimum of Effort to complete the task,
7.      Robust,
8.      On Screen Help Available.
9.      Re-configurable, e.g. Colour, Fonts
10.  Use of WYSIWYG where possible
Internally transparent to the user/ Autoexec macro
1.      All internal mechanisms should be transparent to the user, as this could distract or confuse them.
Guidance not control
1.      Simplified Choices
2.      Validation of data is important, so a screen should be designed so the user can’t make a mistake.
Predictability
1.      All actions should be predictable to the user
2.      Every response should be acknowledged
Reversibility
1.      Dangerous responses should be queried e.g. Are you sure?
2.      Good Recovery From Error.
Consistency
1.      Intuitive to Use
2.      Screen Layout should be consistent. Headings should always be at the top, and instructions should always be in the same place.
3.      Consistent in responses.
Reduces learning load
1.      Cramped or crowded screens should be avoided. The screen should only contain the information needed for the current task..
2.      Users should not be expected to remember chunks of information from one screen to the next.
3.      Use Clear and Concise Wording. Jargon should be avoided in all messages. Messages should also be constructive. They should tell the user exactly what to do i.e. ‘Enter your surname here’ or ‘Press to continue’. They should use the same word or picture for the same thing throughout the system, e.g. Just ‘Exit’ not ‘Quit’, ‘Leave’, ‘Back’
Increases recognition
1.      If a form is represented on the screen, it should follow the same layout as a paper-based version
2.      Items that are grouped should be kept near together on the screen.

20. Design Principles Compatibility Economy Structure
Between user’s mental model & task model
Economy
Minimum number of steps necessary
Structure
To reduce complexity

21. Fonts
Clear and not unusual. Some fonts can be difficult to read, and should be avoided.
Don’t use more than 2 fonts on a page
Take care in spacing fonts - |3 looks like a B. Space it out | 3
You must be careful how you word things, so that they are not misinterpreted.

22. Legibility
Be concise. Icons need careful design in order to be understood
Avoid blinking, zooming or moving text
Font Size to be readable
Left Justified most of the text – can centre or right justify a few lines for effect
Sans Serif Fonts are more readable, but people prefer serif fonts.
Avoid Caps for text

23. Other Factors Spell Check People scan text People don’t like to scroll
Don’t fill your pages with junk
Error Messages – don’t do silly things -

24. The User

25. Types Of User Assess the User Population Frequency Of Use Naive Novice
Skilled
Expert
Frequency Of Use
Regular
Occasional

26. User Characteristics Familiarity with computer systems
Frequency of use
Technophobia
Technomania
Is it compulsory for the job or optional
User physical abilities
Working environment – space, light, noise

27. Style of Interface Command Prompt Menus Direct Manipulation interfaces
Form Filling

28. Command Prompt DOS prompt / User types in command
Gives Little Help To User
User needs knowledge of commands
Powerful / Faster method
User can tell computer concisely what to do
Allow new commands to be defined
Lengthy learning curve / Difficult to program
Inappropriate for inexperienced / infrequent users
Save screen space

29. Menus Item picked from a list on the screen Menu Types
Pull Down, Pop Up, Full Screen, Bar
Useful for limited alternatives
Slow down interaction pace
Take up screen space
Difficult to meaningfully organise
Groupings for menus should be
mutually exclusive, easily identifiable

30. Menu Good for novice users Annoying for expert users (use shortcuts)
Reduce memorisation / Structure decision making
Shorten learning time of a new system
Show default selection
Sub menus can be used to expand choices (must be apparent to users)

31. Direct Manipulation WIMP Interfaces Windows Icons Mouse Pointers
Open more than one at once
Tile or cascade
Mimic a desk
Icons
Direct and understandable
Mouse
Pointers

32. Direct Manipulation Dialogue Boxes Radio and check boxes
List Boxes / Combo Boxes
Scroll Bars
Drag and Drop
Hyperlinks

33. Direct Manipulation Actions which are:
Rapid
Reversible (undo or redo action)
Incremental
Suitable for all levels of interaction
Immediately see if their actions are furthering their goals
Users experience less anxiety
Users gain confidence & mastery

34. Form Filling Useful for data entry Layout similar to paper form
Transition between paper and computer less painful
Must have
Meaningful Title
Relevant Fields with familiar names

35. Users / Interface

36. Useful Functions For all User Types
Context-sensitive Help
Accessible at any point. Should be specific to the situation, clear and concise. More help should be given to novice users.
Good documentation
User friendly, accurate, easy to use, no jargon. Several types of manual including a detailed training guide, a quick training manual, and a trouble-shooting guide. On line help is often used instead of manuals.

37. Normalisation

38. Normalisation
Normalisation provides an algorithm for reducing complex data structures into simple structures
Formalised by set of rules known as Codd’s laws
Tidying up the data so there is no data redundancy
Ensuring data is grouped logically

39. Why Use Normalization?
Relations formed by the process makes the data easier to understand and manipulate.
Provides a stable base for future database growth.
Simplifies relations and reduces anomalies.

40. Stages of Normalization
There are 3 stages:
1st Normal Form – 1NF
2nd Normal Form – 2NF
3rd Normal Form – 3NF
BCNF Boyce Codd Normal Form
4NF also exists

41. First Normal Form – 1NF
For a relation to be in 1NF all its attributes must be atomic
Each attribute must contain a single value not a repeating group of values.
Every non-primary key attribute must be functionally dependent on the Primary Key.

42. Un-normalised data Course Code Course Desc Employee Number Name Block
Room No
Date Joined Course
Allocated Hours
In line with recent policy all staff are released for two hours a week for staff dev. Employees work at their own pace in a lab. A total of six attributes are recorded about each employee including their normal office location (block and room), the date they joined the course and how many hours it is planned for them to work on it.

43. Un-normalised data A list of fields needed for the system
E.g. Staff Development Course
All staff are released for two hours a week for staff dev.
Employees work at their own pace in a lab.
A total of six attributes are recorded about each employee including their normal office location (block and room), the date they joined the course and how many hours it is planned for them to work on it.
In line with recent policy all staff are released for two hours a week for staff dev. Employees work at their own pace in a lab. A total of six attributes are recorded about each employee including their normal office location (block and room), the date they joined the course and how many hours it is planned for them to work on it.

44. First Normal Form (1NF)
An entity is in 1NF if, and only if, it has an identifying key and there are no repeating attributes or groups of attributes
To get to 1NF we must remove all repeating groups (data elements)

45. First Normal Form (1NF)
An entity is in 1NF if, and only if, it has an identifying key and there are no repeating attributes or groups of attributes
To get to 1NF we must remove all repeating groups (data elements)

46. Our Example COURSE EMP_ON_COURSE Course Code Course Desc.
Employee Number
Name
Block
Room No
Date Joined Course
Allocated Hours

47. Second Normal Form (2NF)
An entity is in 2NF if, and only if, it is in 1NF and has no attributes which require only part of the key to identify them uniquely
To get to 2NF we remove part key dependencies
All data items must be dependant on the primary key

48. Our Example Course is already in 2NF Emp_On_Course is not because
Attribute
Depends On
Name
Block
RoomNo
Employee No
Attribute
Depends On
Date Joined
Hours
Employee No + Course Code

49. So we..
Take out details that are linked only to employee into a separate table
If in any doubt, ask a question such as ‘Are these fields affected when they join a course’
Attribute
Depends On
Name
Block
RoomNo
Employee No

50. Cont. COURSE EMP_ON_ EMPLOYEE Course Code Course Desc Emp No
Date Joined Course
Allocated Hours
Name
Block
Room No

51. Problems Don’t loose Employees
Block and Room Number are related, so if one is updated the other will be affected.
If the block names change, then the whole of the employee records will have to be altered

52. Third Normal Form (3NF)
An entity is in 3NF if, and only if, it is in 2NF and no non-key attribute depends on another non-key attribute.
To get to 3NF we must remove attributes that depend on other non-key attributes
It removes any mutual dependence between non-key attributes

53. Third Normal Form 3NF In other words:
“The attributes is a relation in 3NF must depend on the key, the whole key and nothing but the key” !

54. How to do that: Dependency
Decide on the direction of the dependency between the attributes
If B determines A, then A is dependant on B
If A depends on B, create a new entity, keyed by B, with A as an attribute
Leave B in the original entity and mark it as a foreign key, but remove A from the original entity

55. Our Example: Dependency
If, given a value for A, there is only one possible value for B, then B is dependant on A
Therefore, given a value for room no., there is only one value for block. The same is not true vice-versa.
Hence Block is dependent on Room No.
Leave Room No in the original entity and mark it as a foreign key, but remove Block from the original entity

56. Our Example * Room No is a foreign key in the Employee entity
Hence the EMPLOYEE (2NF) entity becomes
EMPLOYEE
LOCATION
Employee No
Name
Room No *
Room No
Block
* Room No is a foreign key in the Employee entity

57. Entity Relationship Modelling
Course
Location
Emp_On_Course
Employee

58. Functional Dependency Notation
The notation for functional dependency is:
A is the determinant
A B
i.e. If we know a StudendId, we also know the associated
StudentName if they are functionally dependent on
StudentId.
The value of studentId uniquely determines the value
of StudentName.

59. Functional Dependency by TransivityIf
A B
and
B C
then
A C
C is transitively dependent on A

60. Background - Keys Primary key Foreign Key Unique Identifier
Can be made up of more than one attribute and then is called a composite key
If there is no obvious choice, use a number
Foreign Key
Does not belong to the entity
Used to relate entity to entity
A primary key in another table

61. To Normalise Follow 3 simple steps Remove all repeating data elements
Ensures data items are dependant on the primary key
Remove all fields dependant on non-key fields