Computer Science Honours 2011

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 Growth of PC in past two decades of 20^th

century put new emphasis on user interface d

design

 Term usability has its roots in 14^th century

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 1980 term changes toward not only making something functional and usable, but also to

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maximize the entire user experience

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U i t f i th ft

 User interface is the software:

 usable software sells better

 unusable web sites are abandonedunusable web sites are abandoned

 usability rating

 ease of use, customer service and no‐hassle installation

installation

 Perception is sometimes superficial

 attractive UI may seem “user friendly”

 users blame themselves for UI failings

 people who make buying decisions are not always end‐users

end users

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http://www.webpagesthatsuck.com

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 Users’ time isn’t getting cheaper

 Design it correctly now, or pay for it later h

 Disasters happen:

 Therac‐25 radiation therapy machine – massive overdose

 Aegis radar system in USS Vincennes – Iranian i li h d

airliner shot down

 Supertanker accident off England – oil spill

 Predator UAV accident in Arizona

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 Usability: how well users can use the system’s functionality

 Usability: how well users can use the system s functionality

 useful – the system supports user objectives

 usable – the system supports these objectives in easy‐to‐use ways

 Dimensions of usability

 learnability: how well the product supports both initial orientation and deeper learning

 memorability: is it easy to remember what you learned

 effectiveness: accuracy and completeness with which users achieve effectiveness: accuracy and completeness with which users achieve specified goals

 efficiency: the speed (with accuracy) in which users complete their tasks

 errors: the ability of the interface to prevent errors or help users

 errors: the ability of the interface to prevent errors or help users recover from those that occur

 satisfaction: how pleasant or satisfying the interface is to use

 ISO 9241‐11 “Guidance on Usability”

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 Depends on the user

 novice users need learnability

 infrequent users need memorability

 experts need efficiency

 But no user is uniformly novice or expert

 domain experience

 application experience

 feature experiencep

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 Designing interactive products to support the way people communicate and interact in

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their everyday and working lives

 Sharp, Rogers and Preece (2007)

 The design of spaces for human communication and interaction communication and interaction

 Winograd (1997)

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 Develop usable products keeping the user experience in mind

 usability means easy to learn, effective to use and provide an enjoyable experience

I l i h d i

 Involve users in the design process

 both directly – through interviews and/or

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questionnaires

 and indirectly – through observation

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VS.

Peanut shaped to fit in hand Peanut shaped to fit in hand

Logical layout and colour-coded, distinctive buttons Easy to locate buttons

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N b f th t d h i i h t

 Number of other terms used emphasizing what is being designed

 user interface design, software design, user‐centred g , g , design (UCD), product design, web design, user

experience (UX), interaction architecture (IA),

participatory design (PD), design research, human

p p y g ( ), g ,

factors

 Interaction design is the umbrella term covering all of these aspects

all of these aspects

 fundamental to all disciplines, fields, and approaches concerned with researching and designing computer‐

based systems for people based systems for people

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“concerned with the design, evaluation, and

implementation of interactive computing systems for human use and with the study of major phenomena surrounding them” – ACM SIGCHI 1992

that “do” interaction design

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Interaction design and user interface design are

 Interaction design and user interface design are inseparable and mutually interdependent

 Interaction design:

▪ the design of how a user communicates, or interacts, with a computer or object

 HCI:

Th t d f h l k ith t d h t

▪ The study of how people work with computers and how computers can be designed to help people effectively use them

 User interface design:

▪ the overall process of designing how a user will be able to interact

▪ the overall process of designing how a user will be able to interact with a software application

 Usability:

▪ the characteristic of being easy to use, usually applied to software, the characteristic of being easy to use, usually applied to software, but relevant to almost any human artefact

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Interaction Design HCI

UID Usability

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http://www.youtube.com/watch?v=91Oitvw qCe8

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 It is no longer enough to design things that merely work

 Greater emphasis now placed on usability,

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user experience and how technology fits into an environment or overall system

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 Software designers have a lot to worry about:

 functionality – usability / interaction design

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 performance – size

 cost – reliability

 security – standardssecurity standards

 Many design decisions involve tradeoffs among different attributes

 We’ll take usability as our primary goal

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Requirements

Design Design

Implement Evaluate

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Design Implement Evaluate

http://www.usabilitynet.org/tools/methods.htm

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 “know thy user”

 who are they?

 what do they already know?

 what is their environment like?

 what are their goals?

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 Design guidelines

 help you to get started

 avoid bonehead mistakes

 no hard‐and‐fast rules ‐ may be vague or contradictory

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 Prototyping of traditional interfaces:

 cheap, throw‐away implementations

 low‐fidelity: paper, Wizard of Oz

 medium‐fidelity: HTML, Java, C#, C++

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 Prototyping of non traditional inputs?

 How can you model a camera based interaction?

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 storyboarding?

 a lot of code! need to know field well

There are tools for rapid prototyping that we will

 There are tools for rapid prototyping that we will examine in this class

 Suede speech based interfaces

 Suede – speech based interfaces

 d.tools and exemplar – physical devices / sensor devices

 Eyepatch vision based interfaces

 Eyepatch – vision based interfaces

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E l i h

 Evaluation puts prototypes to the test

 Two objectives for testing and measuring

1 diagnose usability problems

1. diagnose usability problems

 user based methods

 expert or heuristic evaluation

2. evaluate whether usability objectives have been achieved

bee ac e ed

 requirements for user performance and

satisfaction can be evaluated by performance testing