Computers C.W. Johnson, Univ ersit y of Glasgo w, Glasgo w, - PDF document

Computers C.W. Johnson, Univ ersit y of Glasgo w, Glasgo w, G12 8QQ. Scotland. johnson@dcs.gla.ac.uk, h ttp://www.dcs.gla .a c.uk/ � johnso n Octob er 2001 c CS-1Q: HCI (Lecture 2) � C.W. Johnson, 2001 1

Intro duction � Logical and physical I/O devices. � Dialogue st yles: - text; fo rms; menus; graphics. � WYSIWYG, Metapho r and Direct Manipulation. � Breakdo wn. c CS-1Q: HCI (Lecture 2) � C.W. Johnson, 2001

Input Devices � Several physical devices implement a logical device. Ac kno wledgemen t: Microsoft and Ericsson � T ext input implemented b y: { k eyb oa rds, sp eech recognition, handwriting, gloves. c CS-1Q: HCI (Lecture 2) � C.W. Johnson, 2001

Input Devices � P ointing implemented b y: { mice, touch-screens, track er balls, ey e-tracking. � Cameras also used to p rovide input: { automatic facial recognition using feature extraction. � P eople a re themselves b ecoming input devices: { systems track the user's lo cation. c ontext awar e c CS-1Q: HCI (Lecture 2) � C.W. Johnson, 2001

Output Devices � Printed output: - laser p rinters; ink-jets; impact and thermal p rinters. Ac kno wledgemen t: P anasonic and NEC � Graphical output: - CRT o r LCD displa ys; p rojecto rs. c CS-1Q: HCI (Lecture 2) � C.W. Johnson, 2001

Output Devices � Audio output: - stereo/surround sp eak ers; headphones. � P otential p roblems: - ea rcons o r audito ry icons? - pitch/timb re, relationship to music? c CS-1Q: HCI (Lecture 2) � C.W. Johnson, 2001

Virtual Realit y � Displa ys: helmet mounted o r p rojection. � Input devices: head and b o dy tracking. Ac kno wledgemen t: www.vrealities.com � Many usabilit y issues: - most systems lack fo rce feedback; - stresses on b o dy holding a 3D p osition; - pa rallax p roblems and nausea. c CS-1Q: HCI (Lecture 2) � C.W. Johnson, 2001

Virtual Realit y � F o rce feedback o r haptics : - jo ysticks; moto r-driven feedback; The Bed; - some of these a re input and output devices. � Financial exp ense, relaibilit y etc. c CS-1Q: HCI (Lecture 2) � C.W. Johnson, 2001

Desktop Virtual Realit y � T echnologies: - QuicktimeVR; - Virtual Realit y Ma rkup Language; - DirectX and Spatial Audio. � Many usabilit y issues: - 3D spatial p ositioning with 2D devices; - navigation and w a y-�nding is ha rd; - animation of environments requires scripts; - VRML `face plant'. c CS-1Q: HCI (Lecture 2) � C.W. Johnson, 2001

Dialogue St yles � styles : Dialo gue { manner in which info rmation is p resented and received. � The most common a re: { T ext (emb edded systems, phones); { F o rms ( B2B systems, call centres); { Menus (desktop systems, some w eb interfaces); { Graphics (desktop, palmtops, the w eb). � Most interfaces no w mix all of these st yles; { but p rop o rtions va ry dep ending on users. c CS-1Q: HCI (Lecture 2) � C.W. Johnson, 2001

T ext � onts : F - describ e the shap e of a cha racter; - vs sans-serif. serif � size : Point - determines size of a cha racter; - 1 p oint is a 72nd of an inch. � It's the RELA TIVE not the absolute size. c CS-1Q: HCI (Lecture 2) � C.W. Johnson, 2001

F o rms � Mo re advanced fo rms: { automatic pa rsing, context-sensitive. � Must p rovide title of the fo rm. c CS-1Q: HCI (Lecture 2) � C.W. Johnson, 2001

F o rms � Navigation: { tab to move b et w een �elds; { ENTER to submit the fo rm. � Must p rovide a cancel option. c CS-1Q: HCI (Lecture 2) � C.W. Johnson, 2001

Menus � Many di�erent t yp es: { hiera rchical; pull do wn; tea r-o�; p op-up. � The is 7 + o r - 2. magic numb er c CS-1Q: HCI (Lecture 2) � C.W. Johnson, 2001

Menus � Lo w consequence options at the top. � Dynamic menus recon�gured b y item frequency . c CS-1Q: HCI (Lecture 2) � C.W. Johnson, 2001

Graphics � Icons help to p romote p ro duct identit y . � What is the of the image? semantics c CS-1Q: HCI (Lecture 2) � C.W. Johnson, 2001

WYSIWYG � What y ou see is what y ou get. n slideitem f What get. g you see is not what you � F ew systems p rint exactly what y ou see on the screen. � F onts on the p rinter di�er from those on screen. � Can b e deeply frustrating... � c CS-1Q: HCI (Lecture 2) C.W. Johnson, 2001

Metapho r � Computers rely on bina ry signals, p eople don't. � Provide an abstract view of underlying complexit y . � Sho w a desktop with folders and a trash-can. � Do not sho w complex path info rmation: D: n > Users n profiles n Johns on � c CS-1Q: HCI (Lecture 2) C.W. Johnson, 2001

Direct Manipulation � Go o d metapho rs: - supp o rt skill transfer; - go o d metapho rs reduce training requirements; - go o d metapho rs encourage explo ration. � But systems must supp o rt: dir e ct manipulation { rapid, incremental and reversible actions. � What happ ens when the metapho r b reaks do wn? � c CS-1Q: HCI (Lecture 2) C.W. Johnson, 2001

Summa ry � Logical and physical I/O devices. � Dialogue st yles: - text; fo rms; menus; graphics. � WYSIWYG, Metapho r and Direct Manipulation. � Breakdo wn. � c CS-1Q: HCI (Lecture 2) C.W. Johnson, 2001

F urther Reading � Shneiderman on: - interaction devices pp305-343; - direct manipulation pp 185-228. � Lots mo re, read it fo r op en assessment! � c CS-1Q: HCI (Lecture 2) C.W. Johnson, 2001