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Interfacce per umani vicini e lontani Stefano Levialdi Dipartimento di Informatica Università di Roma, La Sapienza.

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Presentazione sul tema: "Interfacce per umani vicini e lontani Stefano Levialdi Dipartimento di Informatica Università di Roma, La Sapienza."— Transcript della presentazione:

1 Interfacce per umani vicini e lontani Stefano Levialdi Dipartimento di Informatica Università di Roma, La Sapienza

2 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

3 input-output devices  keyboard - mouse - joystick - monitor  are not to be confused with the interface, they may be seen as portals to the interface program

4 Jef Raskin’s definition I  interface: the way that you accomplish tasks with a product - what you do and how it responds (1993)  simple tasks simple interfaces  complex tasks complex interfaces  VCR watch setting 12:30 - minutes + minutes+ hours - hours

5 three 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.

6 second 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

7 example   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.

8 third 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.

9 example   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?

10 positive 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.

11 another 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!

12 example   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.

13 designing 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)

14 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...

15 the ≠ models Model of the userModel of the system

16 value sensitive design Gary 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 10 6 people!

17 formal approaches   formal approaches help in abstracting the details and subtleties of how computers are used; interface features should not be looked at within particular applications undo 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.

18 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”

19 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

20 cognetics 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

21 locus 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

22 habit 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

23 habits & 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

24 L’insegnamento a distanza è variegato  e-learning  contract learning  chunk learning  blended learning  CoD - contents on demand  role playing simulation…

25 Aumento di studenti a distanza (in US) # U.S. students x10 6 ? International Data Corporation

26 Mercato dell’e-learning in Italia ,8 74,8 120, ,

27 Le tre comunità docenti amministrativi studenti

28 Differenze con la didattica tradizionale   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

29 Metodologie d’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.

30 Pro 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

31 Architettura del Sistema MultiCom   Client/Server   TCP/IP   Linguaggio di programmazione: Java   Basi di dati: MySql   Materiale didattico: formato HTML/XML

32 Caratteristiche   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

33 Innovazioni  Java + MySql = Sistema aperto multipiattaforma  XML =  per la comunicazione = indipendenza da protocolli proprietari  per il materiale didattico = gestione flessibile dei documenti

34 Xml (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

35 Architettura SERVER CLIENT Materiale didattico (XML) Dbms Server MultiCom 2 Materiale Didattico scaricato (XML) Dbms Modulo creazione materiale didattico Client – MultiCom 2 Internet Apache MultiCommunity Browser

36 Docenti   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

37 Studenti   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

38 Interfaccia

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