1 ISDE Revision Topics 2012 ISDE Revision Topics 2012 Compiled by Sheila Cassidy-Allan using J Burns slides
Jan 17, 2016
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ISDE Revision Topics 2012
ISDE Revision Topics 2012
Compiled by Sheila Cassidy-Allan using J Burns slides
Exam Details
Date – Thursday 24 MayTime – 9amDuration 2hrs
Suggested time to read scenario and questions 30 minutes
Answer 2 of the 3 questions available
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ISDE Review
Goals of HCISafetyEffectivenessEfficiencyUsabilityAppealJustify Trade offs
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User Centred Activities
User AnalysisPrototypingUsability SpecificationsEvaluationTask Analysis
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User Characteristics
Physical DifferencesGeneral Differences
IntelligenceMotivationKnowledgeEducation
Cultural Differences
ISDE 2009
User characteristics: physical differences
Age (use larger fonts for older people)
Vision limitations, such as colour blindnessOther physical limitations that might restrict
movementSmall children don’t have good fine-muscle
control: see big buttons on next slide
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Frequent Uses/Infrequent User?
How can we design our interface to suit both types of users?
ISDE 2009
System Related User Characteristics
What characteristics can you expect of the users of your interface?frequency of usediscretion to use the systemknowledge of the task which the system will supportknowledge of computersexperience of other similar systemsgeneral abilities, e.g. literacy, visionattitude towards computers (and your system)existing skills (keyboard, mouse)
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Task Analysis
How is it used?How does it inform our design?
Task sequence – in what orderTask Frequency – how oftenTask Criticality – how importantTask Allocation – who or how
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Design Guidelines (Heuristic) use simple and natural dialogue sequencesspeak the users languageminimise user memory loadbe consistentprovide feedbackprovide clearly marked exitsprovide shortcutsprovide good error messagesprevent errors
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Ambiguous Design
What is this?Give an example
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Discretionary User?
What is this?Give an example
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UCD Activities
PrototypingWhat are the key techniques?
Horizontal /Vertical High & Low Fidelity prototypes examples?ThrowawayEvolutionaryIncremental and requirement gathering
+ and – of each
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What is a prototype?
In interaction design it can be (among other things):a series of screen sketchesa storyboard, i.e. a cartoon-like series of scenes a Powerpoint slide showa video simulating the use of a systema lump of wood (e.g. PalmPilot)a cardboard mock-upa piece of software with limited functionality written in the target language or in another language
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General Features of Prototyping
Enables the designer to quickly build or create examples of :-
The data entry formThe menu structure and orderThe dialogue stylesError messages
Should be inexpensive to develop – intention is to discard/modify it
Should not require programming skills
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What to prototype?
•Work flow, task design
•Screen layouts and information display
•Difficult, controversial, critical areas
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Low-fidelity Prototyping
•Uses a medium which is unlike the final medium, e.g. paper, cardboard
•Is quick, cheap and easily changed
•Examples:sketches of screens, task sequences, etc‘Post-it’ notesstoryboards‘Wizard-of-Oz’
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Paper Based Prototyping
Paper based prototypes These have no functionality but can still be useful
for:- Generating ideas Gaining insights into what the user might want or is thinking
Eg a paper based design of a data entry screen
Storyboards and Snapshotsusing “film-scripting” techniques to visualise
interactions between users and the systemThis is very quick and cheap
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Storyboards
•Often used with scenarios, bringing more detail, and a chance to role play
•It is a series of sketches showing how a user might progress through a task using the device
•Used early in design for example check availability or book What are the stages?
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High-fidelity prototyping
•Uses materials that you would expect to be in
the final product.
•Prototype looks more like the final system than a
low-fidelity version.
•For a high-fidelity software prototype common
environments include Macromedia Director, Visual
Basic, and Smalltalk.
•Danger that users think they have a full
system…….see compromises
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Aims of Prototyping in Software
The aim of prototyping is to resolve uncertainty about
functional and user requirementsoperation sequencesuser support needsrequired representations“Look and Feel” of the interfaceappropriateness of the design
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Software Prototyping
A software prototype will be a version of the proposed system with limited functionality
Will differ from the final system in terms ofSize, reliability robustness & completeness
A software prototype is “executable”can be thrown away, or evolvemay serve many different purposesshould be “quick and dirty” (and cheap!) is an integral part of user-centred design approaches
based on evaluation/modification
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Collecting Users Opinions
Questionnaires“open” (free form reply) or “closed” (answers “yes/no”
or from a wider range of possible answers)latter is better for quantitative analysis
important to use clear, comprehensive and unambiguous terminology, quantified where possiblee.g., daily?, weekly?, monthly? Rather than “seldom”,
“often” and there should always be a “never”Needs to allow for “negative” feedbackAll Form Fill-in guidelines apply!
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Components of a usability specification
Statement of the usability goalStatement of the usability attributeusability attributeStatement of the criteriacriteria which will represent
attainment of the specification Now level Worst case Planned level Best case
Statement of which set or subset of usersusers the specification applies to
A statement of preconditionspreconditions for the measurement
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Sample specification
Usability Goal: Users can quickly obtain a balance from an ATMAttribute: TimeMeasuring method: Observe and record Time
taken by users to obtain balance Now level: 30 secsWorst case: 25 secsPlanned level: 20 secsBest case: 15User class: AllPreconditions: Users are familiar with ATMs
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Usability Engineering
What is UE?You should now be able to write a
specification!What are the components of a usability
Specification?
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Interaction Elements
IconsSound/ Music speechVideo/PicturesTextColourWhat are some of the key design issues
surrounding each of these?
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The Primary Styles of Interaction
Q & AMenu selectionForm fill-inCommand languageDirect manipulationNatural language/Anthropomorphic
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Advantages and Disadvantages of MenusAdvantages
shortens learning curve reduces keystrokes structures decision-making permits use of dialogue-management tools allows easy support of error-handling
Disadvantages imposes danger of deep-nested menu hierarchies may slow frequent users consumes screen “real estate” requires rapid display rate
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Advantages and Disadvantages of Form Fill-inAdvantages
simplifies data entry requires modest training makes assistance convenient permits use of form-management tools
Disadvantages consumes screen “real estate”
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Q & A
Simple interaction styleUsers respond to series of questionsInput is usually Y/N or a particular single
inputPrint whole document?No of pages to print?No of copies
Evaluation J T Burns Feb 2010
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Reasons for Evaluation
UnderstandingUnderstanding the real worldparticularly important during requirements
gatheringComparingComparing designs
rarely are there options without alternativesvaluable throughout the development process
EngineeringEngineering towards a targetoften expressed in the form of a metric
Checking conformanceChecking conformance to a standard
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Evaluation Techniques
How applied? – how long, amount of errors (usability spec)
Techniques for doing evaluationsQuestion design
appropriate questionsJustification
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Observation and Monitoring - Direct Observation Protocol
Usually informal in field study, more formal in controlled laboratories
data collection by direct observation and note-takingusers in “natural” surroundingsquickly highlights difficultiesGood for tasks that are safety critical“objectivity” may be compromised by point of view
of observerusers may behave differently while being watched
(Hawthorne Effect)
Evaluation J T Burns Feb 2010
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Heuristic EvaluationUseful where method of operation is not fully
predictable and where user might not be a complete novice
Relies on a ‘team’ of evaluators to evaluate the designEach individually critiques the design –4/5
evaluators discover 75% of problemsSet of Design Heuristics (general guidelines) is
used to guide the evaluators – Prevent errors
Important Lectures to revise
Process of Interaction –wk 4Prototyping – wk 7-8Usability Engineering – wk 8Evaluation – wk 14&15
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