SEG 3210 User Interface Design & Implementation

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1Unit D-Design methods(c) elsaddik

SEG 3210

User Interface Design & Implementation

Prof. Dr.-Ing. Abdulmotaleb El Saddik

University of Ottawa (SITE 5-037)

(613) 562-5800 x 6277

elsaddik @ site.uottawa.ca

abed @ mcrlab.uottawa.ca

http://www.site.uottawa.ca/~elsaddik/

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Unit D: User Centered Design and Prototyping

1. System Centered Design

2. User Centered Design

3. 3. Case Study: Olympic Messaging System (OMS)

4. Participatory Design

5. Design Rationale

6. UI Prototyping

7. Paper-based prototypes

8. Software-based prototypes

9. Where Does All This Fit Into the Software Engineering Process?

10. Key Points to Review

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• What can be built easily on this platform?

• What can I create from the available tools?

• What do I as a programmer find interesting to work on?

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There is no fixed process for HCI design ...• ... Just a series of techniques that have been found helpful• ... And some guidelines to help choose and sequence those

techniques

Key principles of user-centered design:1. It should involve users as much as possible so they can

influence the design

2. It should integrate knowledge and expertise from all the disciplines that influence HCI design

3. It should be highly iterative so testing can be done and so users will be satisfied.

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Some attributes one needs to be a good UI designer:

1. A sense of empathy with users• An ability to understand their mental models• An ability to rapidly learn their domain and tasks

2. Hands-on experience with a wide variety of software.• The more software you see, the more ideas you

will have• Analyze all the software you know for

malfunctions• This will prevent you from repeating errors!

3. Familiarity with UI design techniques and guidelines

Golden rule of interface design: “Know The User”

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Some critical aspects of the general SE process needed to produce good UIs:

(Note: These alone are not enough!)

1. The goal of all activities must be solving the customer’s problem

2. Extensive data gathering and analysis must be done to ensure we understand all aspects of the problem.

3. Well-structured requirements must be reviewed and agreed-to.

4. Foster a disciplined software engineering process.5. Effective regimes must be in place for:

• Quality assurance

• Configuration management

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3. Case Study: Olympic Messaging System (OMS)

Developed by Gould for the 1984 Los Angeles Olympics• Led to the recognition of the term ‘user-centered design’

• Objective:• Develop a system to allow communication among thousands of

people during the Olympics

• Assumptions:• Telephones will not work as people are constantly moving and

participating in events

• Non-computer users

• To be used by over 20 000 people from kiosks

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Some of the techniques used:1. Initial analysis, interviewing, site visits etc.2. Usage scenarios prepared

• Commented on by many people

• Result: Changes made and some functions dropped3. User guide prepared

• Modified 200 times before final version decided4. Simulations constructed and evaluated

• Primary purpose: Designing help messages

• Result: Discovered need for consistent ‘undo’ and ‘go back’ functionality

5. Prototype constructed• Result: Many more iterations

6. ‘Hallway’ method• Soliciting opinions of passers-by

7. ‘Try-to-destroy-it’ method• Hire hackers to try and break it

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Conclusions:1. Focus on users and their tasks early, and keep them central2. Measure reactions using prototype manuals and systems3. Design iteratively because even highly-skilled designers get it

wrong4. Usability factors must evolve together and be under the

control of one group5. The extra work of user-centered design greatly reduces work

later on

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Problem• intuitions wrong• interviews etc not precise• designer cannot know the user

sufficiently well to answer all issues that come up during the design

Solution• designers should have access

to pool of representative users• END users, not their managers

or union reps!

The user is just like me

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• Users become first class members in the design process• active collaborators vs. passive participants

• Users considered subject matter experts • know all about the work context

• Iterative process• all design stages subject to revision

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Advantages• users are excellent at reacting to suggested system designs

• designs must be concrete and visible• users bring in important “folk” knowledge of work context

• knowledge may be otherwise inaccessible to design team• greater buy-in for the system often results

Drawbacks• hard to get a good pool of end users

• expensive, reluctance ...• users are not expert designers

• don’t expect them to come up with design ideas from scratch• the user is not always right

• don’t expect them to know what they want

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Methods for involving the user

At the very least, talk to users• surprising how many designers don’t!

Interviews• used to discover user’s culture, requirements, expectations,

etc.• contextual inquiry:

• interview users in their workplace, as they are doing their job

Explain designs• describe what you’re going to do• get input at all design stages

• all designs subject to revision• important to have visuals and/or demos

• people react far differently with verbal explanations

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5. Design Rationale

Def: the reasoning behind the design of a software It could be understood as either:• The process of choosing among design alternatives• A document carefully explaining why certain design decisions

are made

Who needs design rationale:• Other developers and maintainers

• So the design remains consistent

• So old analysis is not repeated• Trainers

• So they can answer learners’ questions

• Learners may develop a better mental model• Marketing personnel

• So they can answer customers’ questions• New staff or new projects

• So consistency is maintained

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Ways people record design decisions

• Not at all!

• Minutes of meetings

• Buried in lengthy narrative

• Table with ...• Alternatives considered

• Pros and cons of alternatives

• Alternative chosen

• This approach is reasonable

• Diagrams plus tables plus a small amount of narrative• This is ideal but needs computer support to make it fast

• We will look at some diagramming techniques

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Approaches to Document Design

• Issue analysis• Determine UI issues to be resolved and options for their resolution

• Design space analysis• exploration of a space of alternatives

• For several options, determine goals they would achieve

• Claims analysis• Look for ‘claims’ explicit or implicit in a design decision

• Reason about whether the claim is legitimate• e.g. A design has single-letter commands• Implicit claim: This is faster to use• Is it really? Document reasoning

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Issued-Based Analysis

• Originated with the IBIS system in 1970:(Issued-Based Information Systems)

• PHI is a more modern variant (Procedural Hierarchy of Issues)

Steps:1. Build a hierarchy of issues (‘questions’)

• Sub-issues are issues that, if resolved, would help solve higher level issues• Identify high level (prime) issues• Repeatedly identify sub-issues breadth-first

2. Resolve issues starting at the bottom level• List options (positions or answers) i.e. ways of dealing with each

issue

• List arguments for and against each option

• Choose the best answer3. Leave the hierarchy, options, arguments and chosen option in

the design documentation!

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An example issue hierarchy for a library system

How should the user navigate the Library?

How to get more detail?

How to get related books?

How to exit system?

How to go to higher level?

How to go to previous screenHow to

exit?

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Design space analysis

• Exploration of space of alternatives• Better quality because designer will have explored more

alternatives• And documents them at the same time

• Use of QOC notation• Questions: highlight issues that must be considered• Options

• Criteria: argue for or against various alternatives

Steps to make a decision about an issue:1. List the options as in issue analysis2. List positive criteria (benefits gained, or goals achieved by

choosing one or more options).3. Show which criteria argue for or against each option4. Pick the option that best meets goals

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Design space analysis

An example navigation problem:• Mechanisms are needed to

move...• A: Within items on a screen• B: To and from a greater level

of detail• C: To and from related screens

at the same level of detail

Options• Option 1

• A: tab / back tab• B: right arrow / left arrow• B’: left arrow• C: + / -

• Option 2• A: tab / back tab• B and C: return / escape

• Option 3• A: down arrow or tab / up arrow

or back tab• B: return / escape• B’: select ‘higher level’ (A) then

return (B) or escape• C: select ‘up’ (A) then return

(B) /• select ‘down’ then returnA

B

C

B’

?

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Design space (omitting negative criteria)

Option 2

Option 3

Option 1

Easy to browse in a level

Well known protocol

Good mental model

Few keys to learn

Single keys to move

Leaves arrow keys free for editing

Guessing may work since multiple methods achieve same result

Can get to higher level fast

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Using Design rationale

Design rationale is critical in UI design because:• There are usually numerous alternatives

• Unless analysis is systematic, one may• ... pick a suboptimal alternative• ... not even think of one or more alternatives

• Alternatives depend on the context• If the context changes, one can quickly study the reasoning to see

if a system change is needed

Design rationale is good for both• Actively designing• Recording (documenting) the design

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Using Design rationale

As a minimum, use design rationale when:• There is deliberation over a decision• Reviewers raise issues• Opinion war is looming• Accommodation is necessary• Special knowledge is applied• Testing reveals shortcomings• Uncertainty remains• A kludge had to be made

Use issue and design space analysis in a brainstorming environment• And record the results

Analyze all claims (evaluate them)• And record the results

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6. UI Prototyping

UI Prototyping involves a scaled down analysis-design-evaluate cycle• It is an analysis technique

Two key kinds of UI prototypes:• Paper based

• Quick and inexpensive

• Stimulates ideas in a brainstorming environment• Software based

• Demonstrate functionality and usability

• A simulation of the eventual system

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Why is it essential to prototype the UI?

• With technical design documents alone ...• It is hard to imagine ramifications of design decisions

• It is hard to represent interactions in a complete, consistent and readable way

• The system may have high functionality with low usability

• People are much more likely to get the functional aspects of a system right up front

• The UI is where most complaints will come from

• It is too late to start fixing it once the product is built

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7. Paper-based prototypes

Paper-based prototypes• a paper mock-up of the interface look, feel, functionality• “quick and cheap” to prepare and modify

Purpose• brainstorm competing representations• elicit user reactions• elicit user modifications / suggestions

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Paper-based prototypes

Sketches• Drawing of the outward appearance of the intended system• Crudity means people concentrate on high level concepts• But hard to envision a dialog’s progression

Computer Telephone

Last Name:

First Name:

Phone:

Place Call Help

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Storyboarding• a series of key frames

• originally from film; used to get the idea of a scene• snapshots of the interface at particular points in the interaction

• users can evaluate quickly the direction the interface is heading

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Storyboard of a computer based telephone

Computer Telephone Last Name: First Name: Phone:

Place Call Help

Help->

Computer Telephone Last Name: Greenberg First Name: Phone:

Place Call Help

Dialling....

Cancel

Call

connected...

Computer Telephone

Last Name: Greenberg First Name: Phone:

Place Call Help

Connected

Hang up

Call completed...

Return

Help Screen You can enter either the person's name or their number. Then hit the place button to call them

Call by name->

Computer Telephone


Place Call Help

Establishing connection->

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Pictive• plastic interface for collaborative technology initiatives through

video exploration”

• design is multiple layers of sticky notes and plastic overlays• different sized stickies represent icons, menus, windows etc.

• interaction demonstrated by manipulating notes• contents changed quickly by user/designer with pen and note

repositioning

• session is videotaped for later analysis• usually end up with mess of paper and plastic!

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Pictive• can create pre-made interface components on paper• eg, these empty widgets were created in JBuilder/visual basic

and printed out:

buttons menu alert box

combo box

tabs

entries

list box

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Some ideas of paper prototyping

1. Draw diagrams on cards for each screen, window, menu• Don’t worry about being precise; sketch roughly

2. Draw different versions of the cards so you can experiment with which is best

3. Experiment walking through various tasks (‘scenarios’)4. Do the above in a brainstorming environment with users and

colleagues

Keep the design space open as long as possible!• Commit to a particular UI as late as possible• Storyboards are faster and cheaper than computer prototypes

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8. Software based prototype

• Actually works• Must be built quickly and cheaply• Is an integral part of user-centered design

• Evaluation and modification are fundamental• The code is generally thrown away

• But the design is kept!

• In incremental and evolutionary prototyping the code may be kept

• But watch out for unmaintainable code

A requirements animation:• Is a less functional kind of prototype

• A demonstration of the system that acts like a ‘movie’• walks through interactions

• Can be stepped through to illustrate tasks

• Can be quick to set up

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What parts of the UI should you prototype?

As much as possible, but emphasize:1. The top 20% of tasks

• That will usually consume 80% of a user’s time

2. Those aspects of the UI that are considered ‘unusual’ or ‘problematic’• E.g. Screens where you have unusual widgets

• Anything safety-critical, even if only used occasionally

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Approaches to limiting prototype functionality

• Vertical prototypes• includes in-depth functionality for only a few selected features• common design ideas can be tested in depth

• Horizontal prototypes• surface layers includes the entire user interface with no underlying

functionality• a simulation; no real work can be performed

• Scenario• scripts of particular fixed uses of the system; no deviation allowed

Vertical prototype

Horizontal prototype

Scenario

Full System

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Approaches to integrating prototypes and product:

• Throw-away• prototype only serves to elicit user reaction

• creating prototype must be rapid, otherwise too expensive

• Incremental• product built as separate components (modules)

• each component prototyped and tested, then added to the final system

• Evolutionary• prototype altered to incorporate design changes

• eventually becomes the final product

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Presenting SW-based prototype

Painting/drawing packages• draw each storyboard scene on computer

• neater/easier (?) to change on the fly than paper• a very thin horizontal prototype• does not capture the interaction “feel”

Control panel for pump 2

coolant flow 45 %

retardant 20%

speed 100%


coolant flow 0 %

retardant 20%

speed 100%

DANGER!

next drawing

Shut Down Shut Down

(for shut down condition)

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Scripted simulations and slide shows• encode the storyboard on the computer

• created with media tools• scene transition activated by simple user inputs• a simple horizontal and vertical prototype

• user given a very tight script/task to follow• appears to behave as a real system• but script deviations blows the simulation


coolant flow 45 %

retardant 20%

speed 100%

next drawing

Shut Down

(on mouse press over button)


coolant flow 0 %

retardant 20%

speed 100%

DANGER!

Shut Down

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Place Call Help

Return

Help Screen You can enter either the person's name or their number. Then hit the place button to call them


Place Call Help

Computer Telephone


Place Call Help

Computer Telephone


Place Call Help

Dialling....

Cancel

Computer Telephone


Place Call Help

Connected

Hang up


Place Call Help

Help-

Type name and place call

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Constructeurs d’Interfaces

• Outils qui permettent à un concepteur de présenter les gadgets logiciels (widgets) communs

• Mode de construction• changer les attributs des

objets

• Mode de test:• Les objets se comprotent

comme s’ils étaient dans les situation réelles

• Excellent pour montrer l’apparence et les sentiments

• un prototype horizontal plus large

• mais contraint à la librairie de widget

• Les fonctionnalités verticales sont ajoutées sélectivement

• En programmant

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L'évaluation d'un prototype fournit l'information sur

• Séquences de fonctionnalités et des opérations• Assister l'analyse des tâches

• Certains systèmes créent malheureusement des nouvelles tâches pour les usagers!

• e.g. le temps passé à organiser des fichiers, convertir les formats, traduire les schémas de codage

• La convivialité de l’apparence et les sentiments• Les symboles que les usagers peuvent reconnaître

• Ou la disposition ou les messages causent une confusion etc.

• Les besoins du support de l’usager• Ou l’aide et l’entrainement sont necessaires

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Quleques obstacles pour un prototypage efficace

1. Ceci prend du temps• Souvent il est entièrement omis ou l’évaluation est dépassée

• Mais l'évaluation lui donne 70% de sa valeur

2. Beaucoup de gérants n’ont pas l’expérience requise• La gestion peut faire penser que c’est vrai

• “La question n'est pas d’établir un système pilote et le jeter. Vous ferez cela. La question est de projeter à l'avance d’en construire un jetable” - Brooks

• Solution: entraîner les gérants

3. Il est difficile de s'adapter dans un processus contractuel• Particulièrement quand le contrat doit mettre en application des

spécifications données

• Solution: les Contrats doivent être basés sur “la résolution du problème”

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Conclusions à propos du prototypage

• Planifier assez de temps pour prototyper les aspects clés de n’importe quel système

• Évaluer les prototypes de façon appropriée

• Tenir compte que le prototypage seul ne vous donnera pas toutes les réponses

• D’autres techniques sont nécessaires pour générer les idées pour le prototype:

• Analyse des tâches• Modélisation conceptuelle• “Storyboarding”• Raisonnement de conception

• Il manque les issues non fonctionnelles telles que la fiabilité et la sûreté.

• Considérez les produits de concurrence précédents en tant que prototypes additionnels

• Mais vous devez compenser le prototype de toutes les différences ou déviations de ces derniers !

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9. Ou s’adapte tout ceci dans le processus du génie logiciel?

• En développant des interfaces usagers, l'analyse et la conception sont naturellement mélangées

• Il y a trois genres de conception:• Conception architecturale

• comment découper le système en couches

• Conception d’interface• comment faire fonctionner le système avec la tâche et le modèle conceptuel

• Conception détaillée• comment appliquer les écrous et les boulons physiques

User interface layer

Functional layer(s)

API (low-level commands)

(focus of task analysis and conceptual modelling)

(focus of functional analysis)

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Where does all this fit into the SW Eng. process?

General Requirements

Gathering, Scoping and Objective Setting

UI Analysis

& Design

Evaluation

Implementation Task analysis/ functional analysis

Requirements specification

Conceptual design

Prototyping

Detailed design

Architectural

Design

(Splitting system

into layer)

UI

Spec.

API

Spec.

Functional / OO

Analysis

Functional

Prototyping &

Other

Techniques

Detailed Design

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Pensées au sujet des caractéristiques

• L’importance des caractéristiques:• Tenez compte des accords contractuels ou partager avec les

membres d'équipe

• Formez la base pour des conceptions détaillées efficaces

• Forcer la pensée détaillée• mettez souvent les problèmes cachés en évidence

• Il y a un avancement pour rendre des caractéristiques mathématiquement formelles

• Ceci est encore non-réalisable pour les spécifications des IU

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Pensées au sujet des caractéristiques

Séparez clairement les composants suivants des spécifications(préparation rigoureuse en parallèle):

1. Spécifications formelles de l‘API et des couches inférieures• L‘API doit être établi un peu en avant de Spécifications d’IU.

• Décrire les données et les opérations de façon abstraite et précise

• Un prototype n’est pas suffisant

2. Spécification de l’IU• Peut être le résultat de la conception d’IU ou plus formel

• Dépend en quelque sorte des spécifications de l’API mais affecte aussi ce qui va être dans l’API.

• décrit• “look”: l’apparance de l’IU• sensation : détails des interactions

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Pensées concernant la conception de l’API

Ce qui doit être fait au niveau de la couche d’IU:• Compostion et affichage des sorties• Division en écrans; navigation à travers les écrans• Interprétation des évenements• Menus, boutons d’action et “hotkeys”• défilement, restructuration etc.• L’aide

Ce qui doit être fait aux couches inférieures• (i.e. communicant via l’API)• Actions effectuées sur les données• Requêtes pour les données• Requêtes des informations concernant l’état du système ou

l’objet• Charger et sauver les fichiers• Génération de la plupart des structures d’erreurs

• Quelques systèmes peuvent manipuler les « codes » mais ceci bloque les messages fortement utilisables

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Charactéristiques de l’API

• L’API doit servir l’interface usager• Penser en fonction des commandes qui peuvent servir l’usager à

accomplir sa tâche

• S’assurer que les besoins des E/S de l’IU sont servis via l’API• L’API doit permettre la flexibilité

• Replacement de l’IU comme les améliorations sont exigées

• IU alternatif (e.g. accès en ligne, ligne de commande)

• Tests automatiques

• Remplacement des couches inférieures• Les remplacements fournissent le même API

• En dépit de ce qui précède, l‘API devrait être aussi simple que possible

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Charactéristiques de l’API

• L’API doit fournir les opréations atomiques et composées.• Une opération atomique est l’unité de travail la plus petite qui

pourrait être exécutée.• e.g. supprimer un champ

• Une opération composée est une plus grande opération qui devrait être passée à travers l‘API comme un ensemble:

• Pour l’efficacité

• Puisque les opérations composées peuvent agir l'une sur l'autre

• e.g. cupprimer un ensemble de registres• Considérer plusieurs couches avec leur propre API

• Couche inférieure:• Ajouter, supprimer et modifier les objets• Trouver de l’information à propos des objets• Messages d’erreurs peuvent être des codes simples

• Couche du milieu:• Opérations sur des ensembles d’objets• Securité pour contrôler l’accès• Traiter les messages d’erreur

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10. Points essentiels à revoir

• Conception basée sur l’usager• Implique les usagers; hautement itérative

• Intègre la connaissance de plusieurs champs

• Un groupe dans un projet doit avoir le contrôle

• Besoins de conception d’IU: empathie, expérience dans les logiciels, connaissance des techniques et directives

• méthode Hallway et Try-to-destroy-it

• Implique les usagers:• À la toute fin, parler aux usagers

• Entrevues

• Expliquer la conception

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• Conception de raisonnement (design rationale)• Considérer systématiquement toutes les alternatives

• Enregistrer les résultats pour que les autres puissent comprendre

• Peut bénéficier des ingénieurs, entraîneurs, acheteurs, utilisateurs• Analyse d’édition: IBIS

• Explorer les éditions et les options

• Analyser les arguments pour choisir la meilleure option• Concevoir l’analyse d’espace

• Explorer les options et les critères positives

• Faire le lien entre les options et les criteres pour choisir la meilleure option

• Analyse de réclamation:• Raisons pour savoir s'ils sont légitimes

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• Story-boards ou prototypes sur papier• “Brainstorm” à propos des tâches: images de l’interface

• Garder la conception ouverte• Prototypes d’IU

• Essentiels parceque l’IU est une source majeur de problèmes

• Rapides, “cheap”, fonctionnels, généralement jetables

• Incrémentals, evolutionnaires, animations des exigences• Types de conception: ne peut être complètement séparés

• Specifications d’IU

• Architecture: couches d’IU/couches fonctionnelles (API)

• Conception détaillée: Détails physiques

SEG 3210 User Interface Design & Implementation

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Transcript of SEG 3210 User Interface Design & Implementation