Interfacce per umani Interfacce per umani vicini e lontanivicini e lontani

Stefano LevialdiStefano LevialdiDipartimento di InformaticaDipartimento di Informatica

Università di Roma, La SapienzaUniversità di Roma, La Sapienza

interfaces, what for?interfaces, what for?

without interfaces computers would be useless human-computer interfaces are not even as

carefully designed as computer-computer interfaces

computer science has a definite role in the design of human-computer interfaces

creativity is very important in the design of user interfaces

input-output devicesinput-output devices

keyboard - mouse - joystick - monitorkeyboard - mouse - joystick - monitor

are not to be confused with the are not to be confused with the interface, they may be seen as interface, they may be seen as portalsportals to the interface programto the interface program

Jef Raskin’s definition IJef Raskin’s definition I

interfaceinterface: the way that you accomplish : the way that you accomplish tasks with a product - what you do and tasks with a product - what you do and how it responds (1993)how it responds (1993)

simple tasks simple tasks simple interfaces simple interfaces complex tasks complex tasks complex interfacescomplex interfaces VCR watch settingVCR watch setting

12:30- minutes

+ minutes+ hours

- hours

three key issuesthree key issues

1-Predictability by picking a metaphor that the user

understands, then staying consistent with those rules

at all costs. predictability eliminates training time

and allows the user to make associations and jump chasms in self-training.

second issuesecond issue

2-Consistency once you create a behavior you stick with it. all windows or menus behave the same, a shortcut key that always does the same thing

(even across programs), mouse button or action always do the same

thing; configurability is often necessary, but is usually the enemy of predictability and consistency because a user can change something so that it is no longer predictable

exampleexample imagine someone rewired your car so that when

you pushed in the cigarette lighter it would ignite the car’s gas tank,

while this might be a nifty option (very James Bond) it is definitely unpredictable, especially if there is no warning label. Ironically, your cigarette WOULD get lit, so the label is accurate. While you might WANT this feature, there is very little probability you would like it! it.

third issuethird issue 3-Information

information display is about how much information you can get to the user, while still preserving screen real estate (and not being cluttered or overly complex),

this means choosing what is valuable information and displaying it - and NOT displaying irrelevant information,

more is not better, unless you NEED more. Efficiency and relevancy of the data presentation are most important.

exampleexample imagine if everything about your car was displayed in a myriad of

gauges all across your dashboard; even to the point where it obscured your view (imagine an airplane cockpit and you get the idea),

while it might be nice to know what the tire pressure is, or the relative humidity in the cars trunk, it is not necessary information. So this information would merely be available to impress your friends. Not only is the information useless, the overabundance of information and clutter would actually hinder you from getting work done (driving), by blocking your view and making you search for the information you care about.

is that the fuel temperature, fuel mixture, fuel pressure, or just the amount of fuel I have left?

positive featurespositive features

Prioritizing - Apple decided that the information on the screen should be displayed and positioned by importance. Immediate actions always appear in the center of the screen (dialogs/alerts/status). It is ordered like western reading/writing; upper-left is most important (first), lower-right is least important.

another featureanother feature

Simplicity: the word speaks for itself. Never make the user do two steps to complete an operation when one step will do. Never ask the user things they don't care about.

The other part of simplicity is to avoid adding so many functions that users can't remember HOW to do something. Simple choices, simple methods. KISS!

exampleexample Example: Imagine if to start your car, you had

to set the manual choke, hand prime the carburetor, crank a generator while simultaneously counter cranking a manual starter. Of course there would be a shortcut that if you crawled underneath your car, there would be a “start” button, but that wouldn't be in the manual.

designing human interfacesdesigning human interfaces

two sides of the design problem:

1) computer science issues (essentially programming a chosen set of algorithms favouring human-program communication and control) and

2) human issues (essentially exploiting and supporting user's skills)

on the design...on the design...

user interface design: complexities of the human-program communication needs + peculiarities of classes of human users: they should all be interviewed, understood, modelled, taken care of, documented, tested, validated, refined...

the ≠ modelsthe ≠ models

Model of the user Model of the system

value sensitive designvalue sensitive designGary Chapman 2000Gary Chapman 2000

chief privacy officer proprietary calendaring (Microsft, SUN) power over design: marks the difference expert systems or systems for experts?

(Scandinavian approach) web sites & on-line services: “opt-in” or “opt-

out”? a technical standard may influence 106 people!

formal approachesformal approaches

formal approaches help in abstracting the details and subtleties of how computers are used; interface features should not be looked at within particular applicationsundo in an airline reservation system ≠ in undo in an interactive system

general rules have been abstracted: low cognitive load, few basic icons, possibility of undoing all actions, bactracking availability, on-line help, etc.

usability R.B. Miller [Mil71] “a property reflecting the ease-of-

use of an information system” a broader view [91] “a feature based on 4 basic

factors: 1) effectivity, 2) learnability, 3) flexibility and 4) attitude”

Bevan [Bev93] “the level of efficacy, efficiency and satisfaction reached by a product which is employed by a class of users in order to reach given goals in specific environments”

Standard ISO 9241 (november 1995) D. Redmiles [Red02] “a property concerning systems

both useful and usable to which users have the right to access”

a few considerations...a few considerations...

as far as the user is concerned, the interface IS the product

the system should treat all user input as sacred

a computer should not waste your time or require you to do more work than is strictly necessary

an interface is humane if it is responsive to human needs and considerate to human frailties

cognetics at workcognetics at work

users should set the pace of an interaction know thyself - ergonomics of the mind we must deal with unconscious &

conscious cognitive aspects of the human mind

different definitions have been coined to describe these two different cognitive aspects

locus of attentionlocus of attention

to focus - voluntary action locus of attention - might both be voluntary

or unaware one may concentrate on only 1 locus of

attention visual perceptions decay in 200 ms auditory perceptions decay in 1500 ms not all perceptions become memories

habit formationhabit formation

with repetition or practice, competence becomes habitual

any habit is a surrender of detail control “to fall into a habit is to begin to cease to

be” - Unamuno persistent use of an interface will cause to

develop habits...unable to avoid... create interfaces that do not allow habits

to cause problems to the user

habits & designhabits & design

take advantage of human habit formation allow users to develop habits that smooth

the workflow many ways of accomplishing the same

task: requires the shift of locus of attention to choose the “best” way

a habit cannot be undone by any single act of willpower - retraining is needed

L’insegnamento a distanza è L’insegnamento a distanza è variegatovariegato

e-learninge-learning contract learningcontract learning chunk learningchunk learning blendedblended learning learning CoD - contents on demandCoD - contents on demand role playing simulation…role playing simulation…

Aumento di studenti a distanza Aumento di studenti a distanza (in US)(in US)

2001 2002 2003

# U.S. students

106 2x106

?

International Data Corporation

Mercato dell’e-learning in Mercato dell’e-learning in ItaliaItalia

1929

45,8

74,8

120,6

191

297,1

0

50

100

150

200

250

300

350

2000 -01 - 02 -03 -04 -05 -06

Le tre comunitàLe tre comunità

docenti

amministrativi

studenti

Differenze con la didattica Differenze con la didattica tradizionaletradizionale

Al centro dell’attenzione non c’è più il soggetto ma il contenuto dei messaggi

La discussione non è dominata soltanto dai soggetti più estroversi ma anche i più timidi trovano uno spazio per esprimersi

Passaggio dalla cultura dell’insegnamento a quello dell’apprendimento: lo studente non è più un oggetto dell’insegnamento ma diventa il soggetto dell’apprendimento

Metodologie Metodologie d’apprendimentod’apprendimento

le attività cooperative la partecipazione degli

studenti e degli insegnanti

le nuove conoscenze emergenti da un dialogo con scambio di idee ed informazioni

[Turoff, 1995]

Collaborativo Personalizzato

possibilità di scegliere il percorso di studio più congeniale alle sue inclinazioni & esigenze

procede secondo il proprio ritmo.

Pro e ControPro e Contro

Flessibilità di spazio Flessibilità di tempo Condivisione delle

risorse Aumento dell’utenza Miglior gestione del

contenuto formativo Diminuzione dei costi

Difficoltà nell’uso delle tecnologie informatiche

Difficoltà nell’utilizzo della scrittura per comunicare

Mancanza di segni di comunicazione non verbale

Sovraccarico di messaggi da leggere

Pro Contro

Architettura del Sistema Architettura del Sistema MultiComMultiCom

Client/Server TCP/IP Linguaggio di

programmazione: Java

Basi di dati:MySql

Materiale didattico:formato

HTML/XML

CaratteristicheCaratteristiche Multipiattaforma Base dati per gestione di informazioni e di materiale didattico Comunicazione client-server e server-base di dati: protocollo

XML Serivizi di comunicazione:

Sincroni: chat Asincroni: posta elettronica, Forum, Faq,bacheca

Interazione fra docenti, studenti ed amministrativi Contenuti originali in Power Point 98, Word 98, html Materiale didattico su server scaricabile in locale Collegamenti ipertestuali fra corsi diversi

InnovazioniInnovazioni

Java + MySql = Java + MySql = Sistema aperto multipiattaformaSistema aperto multipiattaforma

XML =XML = per la comunicazione = indipendenza da per la comunicazione = indipendenza da

protocolli proprietariprotocolli proprietari per il materiale didattico = gestione flessibile per il materiale didattico = gestione flessibile

dei documenti dei documenti

Xml Xml (eXtensible Markup Language(eXtensible Markup Language

Per molte applicazioni e per diversi settori, gli esperti hanno già creato linguaggi di markup specifici, come ad esempio il Channel Definition Format, il Mathematical Markup Language ed altri, il Learning Material Markup Language.

E’ un metalinguaggio che permette di creare dei linguaggi personalizzati di markup

ArchitetturaArchitettura

SERVERSERVER

CLIENTCLIENT

Materialedidattico (XML)

Dbms

ServerMultiCom 2

MaterialeDidattico scaricato

(XML)

DbmsModulo

creazionematerialedidattico

Client – MultiCom 2

Internet Internet

Apache

MultiCommunity

Browser

DocentiDocenti

Accesso alle informazioni generiche e/o a quelle relative ai corsi

Gestione del materiale didattico Suddivisione degli studenti in gruppi Amministrazione ed utilizzo di:

Bacheche online, Faq, Newsgroup Messaggi, Chat

StudentiStudenti Iscrizione e richiesta dei corsi attivi Iscrizione ad un nuovo corso Accesso alle informazioni generiche e/o a quelle

relative ai corsi ed al materiale didattico Gestione del materiale didattico sul server * Suddivisione degli studenti in gruppi * Amministrazione * ed utilizzo di:

Bacheche online, Faq, Newsgroup Messaggi, Chat

* su autorizzazione

InterfacciaInterfaccia