Hvad er usability? IT Universitetet i København Februar 2006 John Paulin Hansen

Flexibility-usability tradeoff

De 8 gyldne regler Konsistens - brydes mest ofte Understøt regelmæssige brugere Giv informativ feedback Afslut ordentligt Undgå fejl - og vær tolerant Fortrydelsesmuligheder Giv brugerne kontrollen Undgå overlast af korttidshukommelsen - understøt chunking

Fysiske grænser

Psykologiske grænser

Regelmæssige brugere

Forhindre fejl

Gould & Lewis 3 grundprincipper (1985) 1)Tidlig fokus på brugerne: Designere må i direkte kontakt med brugeren og forstå deres arbejde 2) Empiriske tests: Observationer, målinger og analyser på prototyper 3) Iterativt design: design, test, re- design, test osv.

Designprincipper På ordre (ovenfra) Vandfaldsmodellen –analyse, kravsspecifikation,design, udvikling og test Den iterative spiral: –Eksamination, definition, udvikling, eksamination, definition, udvikling......

Grunde til dårlig usability Fokus på teknik/maskine/system frem for brugeren Brugergruppen har ændret sig Design betragtes bare som ”common sense” Systemelementerne udvikles separat af specialistgrupper som ikke koordineres [fortsæt selv]

Gazetalk Commercial cameras Type-to-talk Synthetic speech MP3 player PDF reader Webbrowser Freeware and Open Source Danish, English and Japanese versions

Request Date: Tue, 06 Feb :41: Hi there I stay in South Africa and my father has had a brain stem stroke. He cannot move or speak. He can communicate with his eyes. We are currently using an alphabet chart, but it takes too long and he gets tired quickly. I'm looking for some type of EyeMouse. Something we can plug into a PC, Design like a virtual keyboard. Can you please advise me. I will appreciate any help. Thanks Nuno Lourenco

Reply Dear Nuno, I'm sorry to tell you but eye trackers that are accurate enough for your father to indicate at which letter your father is looking at are much too expensive and are not available for private use. If your father still can hear, you can ask him to look left or right or up or down under certain conditions. It may work as a yes or no. Lo Bour, PhD Department of Neurology/Clinical Neurophysiology, H2-222 Academic Medical Centre, University of Amsterdam

System requirements Fast Robust Mobile Affordable Changes with progress of diseases

Progress of ALS disease (amyotrophic lateral sclerosis) Loss of voice Reduced control of arms and legs Reduced control of fingers Reduced head movements Just eye movements

Problems with some existing systems –Difficult or impossible to calibrate - needs helper –Mostly for stationary, indoor use –Requires a rather complicated installation by computer experts –The price is prohibitive (more than $)

Standard cameras and PC Advantages: –High availability –Instant operation –Low cost –Steady increase in performance –System support Video cam Web cam

Design Proces 2000: DKM-studerende lavede prototype 2001: Usability studenter testede første version og kom med kritik 2002: Forbedrede versioner testes af ALS-patienter og usabilitystudenter afprøver nyt indtastningsprincip 2003: Kontrollerede eksperimenter 2005: Udvides med MP3 spiller, PDF-læser og web-browser 2006: Nye brugertest til simplificeringer.

Forbedringsforslag

Means-end of requirements