ISI Flashcards
Computers have become (improvements):
Cheaper
Smaller
More reliable
More powerful (faster + more storage
Early computer interfaces include:
Manchester Mark 1, IBM PC, BBC Micro
Features of modern GUI:
Use of: multiple overlapping windows,
icons to represent files & actions,
menus to display commands,
pointing device i.e. a mouse
Syntax is…
The structural or grammatical rules that define how symbols in a language are to be combined to form words, phrases & expressions. Language structure - how
Semantics is…
The meanings assigned to symbols and sets of symbols in a language. Language meaning - purpose
Possible future trends of user interface
More use of natural language integration, miniaturisation which will allow ‘wearable’ computing, 3D graphic interfaces, biological interfaces
Factors affecting development
Technical
Socio-economic
Technical factors affecting development
Hardware/software. Modern interfaces make big demands on hardware. They require: see sheet
Socio-economic factors affecting development
Expertise of users. Competition between companies e.g. Apple & Microsoft.
Interface modes
Graphical
Textual
Sensory
Multimodal
Graphical interfaces
Provide direct manipulation of objects e.g. Trash, save, open, print icons.
Textual interfaces
User enters commands by typing on keyboard. Results appear displayed as text
Advantages of textual interface over GUI
Less demands on system (processor time, memory requirements), precise commands can be made, which can be incorporated into a program (script), save time: user doesn’t need to move hands from keyboard to mouse
When is Textual interface more appropriate?
On small devices where GUI is impractical, for form-filling applications
Sensory interfaces e.g. Touch/sight
User receives information by seeing the screen and inputs information by touching the keyboard or pointing device
Touch-based devices
Touch pads (on laptops), Touch sensitive switches (on domestic appliances), Touch sensitive screens (on palmtop devices and public information devices)
Haptic interface
Used to describe interfaces that are based on the sense of touch
Sensory interface: sound
Sound can be used for alerts, speech output, speech input (natural language)
Speech output
Easily implemented, can be important for blind/partially sighted users, spoken alert to give additional emphasis to visual output
Speech input (natural language)
Requires much more complex processing e.g. Siri
Multimodal interfaces
Interfaces which combine to or more modes of interface in an integrated way e.g. Some form of sensory & text, sensory & graphic (speech & graphical)
World-wide-web
Required more user-friendly interface so HTML was created and software to display HTML documents - browser
To describe an interface, you must:
List all hardware devices used for input/output (keyboard,mouse,touchpad/monitor,loudspeaker etc) and explain how they are used
Typical users of a system
Novice users
Knowledgeable intermittent
Expert/frequent user
Novice users of a system
Have no expertise relevant to the application, so need the system to provide easily accessible advice and help
Knowledgeable intermittent of a system
Have used the system before, but may not do so often, so they may forget details of how to use it
Expert/frequent users of a system
Do not need the system to give them help unless they are accessing some unfamiliar section
Physical constraints
Size, weight, power requirements etc
Comparing mobile phones
Size, weight, output display, price, features
Describing the interface of a mobile phone
Mode, methods of input and output, typical users, physical constraints
PDA stands for:
Personal digital assistant
Examples of PDA Operating Systems
Palm OS
Windows mobile
Blackberry
Bluetooth is:
A technical industry standard that facilitates communication between wireless devices such as mobile phones, PDAs, handheld computers, laptops/desktops
Other interfaces
ATMs
kiosks
Where/How are kiosks used?
Corporate
Shopping Mall
Entertainment & Leisure
Libraries
Kiosks used in Corporate
Reception areas, visitor sign in, company introduction for visitors, multiple information pads
Kiosks used in Shopping Malls
Shop & floor layouts, product locator within mall, virtual “try-on” of personal goods, advertising video when not accessed, forthcoming shopping mall events, special offers from specific shops
Kiosks used in Entertainment & Leisure
Museum exhibit enhancement, sound & vision, FAQ interrogation, on request detailed info of museum exhibits
Kiosks used in libraries
Search for books, search for books via subject matter, reserve books not presently in library, self-serve ticket purchase system
Features of an intelligent interface
Adapt to needs of different users, learn new concepts & techniques, anticipate needs of user, take initiative & make suggestions to user, provide explanation of its actions
We need intelligent interfaces because:
Interfaces and software are becoming to complex, most current interfaces are inflexible, interfaces need to change when the user’s needs change
Intelligent interfaces
Predictive text messaging, spell & grammar checkers, adaptive menus, agents
Active agents
Appear as life-like characters, plan interactive behaviour autonomously, can initiate interaction
Interactive agents
Understand the user’s requests, answer clarification questions
Re-active agents
Respond immediately to interruptions
Proactive agents
Anticipate the user’s needs, adopt the user’s goals, provide unsolicited comments
NLP
Natural Language Processing
What is Natural Language Interaction?
Allows computer systems to work with natural language rather then the formal language it is designed to be able to use.
Formal languages
Include high level programming languages e.g. Pascal and low level machine languages. Straightforward, small vocab, meanings of words are unambiguous, rules (syntax) of language are defined very precisely.
Stages of natural language processing
Converting sound into digital data, splitting sound into phonemes, identifying words, extracting meaning, generating a response
Applications of NLP
Machine translation, database query systems, speech-driven word processors, command & control systems, natural language search engines
Reasons why good user interface design is important
User satisfaction, user efficiency & productivity, reduced maintenance & support costs, safety, legal requirements
Design methodologies
System-centred design
User-centred design
“No design” methodology
System-centred design
Design team thinks about what can be built easily on this platform, what can be created using existing tools etc. Focus on on hardware/software & designer. User is thought about later
User-centred design
What does user need to be able to do, what is user’s level of ability? User must be included in design process. Partnership between user & design team throughout the whole design process
“No design” methodology
Developers muddle along without any clear principles or jump straight into implementation without doing the necessary analysis and design work first
LUCID Methodology
Envision, discovery, design foundation, design detail, build, release
Stages included in envision
See sheet
Envision stage completed when:
See sheet
Purpose of discovery stage:
To develop a clear and detailed understanding of: the users of the application, user requirements, user environment
Design foundation is concerned with…
Establishing the major design decisions including: design metaphor, key screen layouts, navigation between layouts, colour scheme & key graphics
Design detail
See sheet
During the build stage…
Developers carry out all the coding to create the system, modules are tested as they are developed, usability evaluation is carried out, user documentation is written
Classes of user
Novice
Knowledgeable intermittent
Expert/frequent
Low fidelity prototyping
Usually paper-based, provide paper mock-up of the look, feel & functionality of the proposed interface. Simple quick & cheap to prepare/modify
Purpose of low fidelity prototyping
Brainstorming ideas for layout, illustrating design ideas, getting customer or user feedback on ideas, choosing from a variety of possible designs
Horizontal prototype
Represents in detail all the visible aspects of the use interface - all details of colour, fonts, layout, menus, actin buttons etc.
Vertical prototypes
Include some functionality but on,y for one or two selected features. From a particular form or screen there may be several options leading to other forms/screens. May have in-depth functionality for one of these
High fidelity prototype
Will often be written using the software development environment (programming language) which will be used for the final version.
Usability
Ease of learning, efficiency of use, memorability, error frequency & severity, subjective satisfaction
Ease of learning
How fast can a user who has never seen the user interface before learn it sufficiently well to accomplish basic tasks?
Efficiency of use
Once an experienced user has learned to use he system, how fast can they accomplish tasks?
Memorability
If a user has used the system before, can they remember enough to use it effectively the next time or does the user have to start over learning everything
Error frequency & severity
How often do users make errors while using the system, how serious are these errors, how do users recover from these errors?
Subjective satisfaction
How much does the user like using the system?
Qualitative techniques
Thinking aloud protocol
Co-discovery method
Question-asking protocol
Eye tracking
Thinking aloud protocol
Participant performs a task using the system. Whilst doing the task, they speak aloud their thoughts, feelings & opinions whilst interacting with the product
Co-discovery method
2 participants attempt to perform tasks together while being observed
Question asking protocol
Tester/developer prompts a user performing a task on the system by asking direct questions about the product. The ability or lack of ability to answer questions highlights areas of the interface which require improvement
Eye tracking
Allows testers to identify what users look at during the course of a usability test. A beam of light is projected into the user’s eye; a sophisticated camera picks up the difference between the pupil reflection and known reference points to determine what the user is looking at
Quantitative techniques
Time to learn Speed of task performance User error rates User retention of commands User satisfaction
Time to learn
Users want easy to learn software and so when considering time for learn, previous training/knowledge should be considered.
Speed of task performance
Clearly defined tasks can be set up & average time to complete them can be measured. Most useful when 2 alternative designs are being considered
Error rates
How often does a user make an incorrect choice
User retention of commands
How long can elapse before a user forgets how to carry out a task
User satisfaction
Can be judged qualitatively or quantitatively
Quality Inspection Methods
Heuristic evaluation, walkthroughs, feature sets, consistence inspections, adherence to standards
Heuristic evaluation
Small groups of experts are asked to evaluate every element of an interface against an agreed set of usability heuristics (generally agreed principles of good interface design)
Walkthroughs
When an expert adopts the role of a potential user & works their way through a task using the system. The expert records any problems that arise
Feature sets
Once major design decisions have been made further evaluations can be made of specific feature sets e.g. In word processing application - related to common tasks such as editing features, layout control features etc. Each set can be evaluated separately & independently to ensure they meet requirements
Consistency inspection
Ensure consistency across multiple products from the same company.
Questionnaire
Sent out to users who complete it by themselves by answering all the questions and then return it to sender
Survey
Completed during a one-to-one interview with user. Researcher asks questions and fills in the user’s responses. Can be done on phone or face-to-face
