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Lecture 6Lecture 6(Ref. Chapter 8)(Ref. Chapter 8)

Design, prototyping and Design, prototyping and constructionconstruction

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OverviewOverview •Prototyping and construction

•Conceptual design

•Physical design

•Tool support

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Prototyping and Prototyping and constructionconstruction

•What is a prototype? •Why prototype?•Different kinds of prototyping

low fidelityhigh fidelity

•Compromises in prototypingvertical horizontal

•Construction

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What is a prototype?What is a prototype?

In other design fields a prototype is a small-scale model:

a miniature cara miniature building or town

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What is a prototype?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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Why prototype?Why prototype?

•Evaluation and feedback are central to interaction design•Stakeholders can see, hold, interact with a prototype more easily than a document or a drawing•Team members can communicate effectively•You can test out ideas for yourself •It encourages reflection: very important aspect of design •Prototypes answer questions, and support designers in choosing between alternatives

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What to prototype?What to prototype?

•Technical issues

•Work flow, task design

•Screen layouts and information display

•Difficult, controversial, critical areas

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Low-fidelity PrototypingLow-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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StoryboardsStoryboards

•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

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SketchingSketching

•Sketching is important to low-fidelity prototyping

•Don’t be inhibited about drawing ability. Practice simple symbols

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ActivityActivity

Produce a storyboard that depicts how Produce a storyboard that depicts how to use a change machine to get to use a change machine to get change.change.

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•Index cards (3 X 5 inches)

•Each card represents one screen

•Often used in website development

Using index Using index cardscards

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‘‘Wizard-of-Oz’ prototypingWizard-of-Oz’ prototyping•The user thinks they are interacting with a computer, but a developer is responding to output rather than the system. •Usually done early in design to understand users’ expectations

>Blurb blurb>Do this>Why?

User

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High-fidelity prototypingHigh-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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Compromises in prototypingCompromises in prototyping•All prototypes involve compromises•For software-based prototyping maybe there is a slow response? sketchy icons? limited functionality? •Two common types of compromise

• ‘horizontal’: provide a wide range of functions, but with little detail• ‘vertical’: provide a lot of detail for only a few functions

•Compromises in prototypes mustn’t be ignored. Product needs engineering

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Construction Construction

•Taking the prototypes (or learning from them) and creating a whole

•Quality must be attended to: usability (of course), reliability, robustness, maintainability, integrity, portability, efficiency, etc

•Product must be engineered

Evolutionary prototyping

‘Throw-away’ prototyping

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Conceptual design: from Conceptual design: from requirements to designrequirements to design

•Transform user requirements/needs into a conceptual model •“a description of the proposed system in terms of a set of integrated ideas and concepts about what it should do, behave and look like, that will be understandable by the users in the manner intended” •Don’t move to a solution too quickly. Iterate, iterate, iterate•Consider alternatives: prototyping helps

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Three perspectives for a Three perspectives for a conceptual modelconceptual model

•Which interaction mode?•How the user invokes actions•Activity-based: instructing, conversing, manipulating and navigating, exploring and browsing. •Object-based: structured around real-world objects

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Three perspectives for a Three perspectives for a conceptual modelconceptual model

•Which interaction paradigm? desktop paradigm, with WIMP interface (windows, icons, menus and pointers),ubiquitous computingpervasive computingwearable computingmobile devices and so on.

•Is there a suitable metaphor?(contd)….

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Is there a suitable metaphor?Is there a suitable metaphor?

•Interface metaphors combine familiar knowledge with new knowledge in a way that will help the user understand the product.

•Three steps: understand functionality, identify potential problem areas, generate metaphors

•Evaluate metaphors:How much structure does it provide?How much is relevant to the problem?Is it easy to represent?Will the audience understand it?How extensible is it?

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Expanding the conceptual modelExpanding the conceptual model

•What functions will the product perform? What will the product do and what will the human do (task allocation)?

•How are the functions related to each other? sequential or parallel?categorisations, e.g. all actions related to telephone memory storage

•What information needs to be available?What data is required to perform the task? How is this data to be transformed by the system?

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Using scenarios in conceptual designUsing scenarios in conceptual design

• Express proposed or imagined situations • Used throughout design in various ways

1. As a basis for the overall design2. for technical implementation and scripts

for user evaluation of prototypes3. As a means of cooperation within design

teams 4. as a means of co-operation across

professional boundaries• Plus and minus scenarios to explore extreme

cases

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Using prototypes in conceptual Using prototypes in conceptual designdesign

•Allow evaluation of emerging ideas

•Low-fidelity prototypes used early on, high-fidelity prototypes used later

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Physical design: getting Physical design: getting concreteconcrete

•Considers more concrete, detailed issues of designing the interface•Iteration between physical and conceptual design•Guidelines for physical design

Nielsen’s heuristicsShneiderman’s eight golden rules (See next slide)Styles guides: commercial, corporate

decide ‘look and feel’ for youwidgets prescribed, e.g. icons, toolbar

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Shneiderman’s 8 golden rules

1.1. Strive for consistencyStrive for consistency2.2. Enable frequent users to use shortcutsEnable frequent users to use shortcuts3.3. Offer informative feedbackOffer informative feedback4.4. Design dialogs to tied closureDesign dialogs to tied closure5.5. Offer error prevention and simple error Offer error prevention and simple error

handlinghandling6.6. Permit easy reversal of actionsPermit easy reversal of actions7.7. Support internal locus of controlSupport internal locus of control8.8. Reduce short-term memory loadReduce short-term memory load

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Physical design: getting Physical design: getting concreteconcrete

•Different kinds of widget (dialog boxes, toolbars, icons, menus etc)

menu designicon designscreen designinformation display

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Menu designMenu design

•How long is the menu to be?

•In what order will the items appear?

•How is the menu to be structured, e.g. when to use sub-menus, dialog boxes?

•What categories will be used to group menu items?

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Menu designMenu design

•How will division into groups be denoted, e.g. different colors, dividing lines?

•How many menus will there be?

•What terminology to use? (results of requirements activities will indicate this)

•How will any physical constraints be accommodated, e.g. mobile phone?

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Icon designIcon design

•Good icon design is difficult•Meaning of icons is cultural and context sensitive•Some tips:

always draw on existing traditions or standardsconcrete objects or things are easier to represent than actions

•From clip art, what do these mean to you?

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ActivityActivity

Think a usual operation in a video Think a usual operation in a video conference or a chatting room and conference or a chatting room and create an icon for it.create an icon for it.

Let others think what it means.Let others think what it means. Check if it is similar to your original idea.Check if it is similar to your original idea.

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Screen designScreen designTwo aspects:

•How to split across screens moving around within and between screenshow much interaction per screen?serial or workbench style?

•Individual screen designwhite space: balance between enough information/interaction and claritygrouping items together: separation with boxes? lines? colors?

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Screen design: splitting functions Screen design: splitting functions across screensacross screens

•Task analysis as a starting point

•Each screen contains a single simple step?

•Frustration if too many simple screens

•Keep information available: multiple screens open at once

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Screen design: individual screen Screen design: individual screen designdesign

•Draw user attention to salient point, e.g. colour, motion, boxing•Animation is very powerful but can be distracting•Good organization helps: grouping, physical proximity•Trade off between sparse population and overcrowding

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Information displayInformation display

•Relevant information available at all times

•Different types of information imply different kinds of display

•Consistency between paper display and screen data entry

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Tool SupportTool Support 9 facilities that user interface software tools should 9 facilities that user interface software tools should

provide:provide:

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SummarySummary•Different kinds of prototyping are used for different purposes and at different stages

•Prototypes answer questions, so prototype appropriately

•Construction: the final product must be engineered appropriately

•Conceptual design (the first step of design)

•Physical design: e.g. menus, icons, screen design, information display

•Prototypes and scenarios are used throughout design