paradigms how can the usability of an interactive system be - PDF document

why study paradigms Concerns chapter 4 – how can an interactive system be developed to ensure its usability? paradigms – how can the usability of an interactive system be demonstrated or measured? History of interactive system design provides paradigms for usable designs What are Paradigms Paradigms of interaction New computing technologies arrive, • Predominant theoretical frameworks or creating a new perception of the scientific world views human—computer relationship. – e.g., Aristotelian, Newtonian, Einsteinian ( relativistic) paradigm s in physics We can trace some of these shifts in • Understanding HCI history is largely about understanding a series of paradigm shifts the history of interactive technologies. – Not all listed here are necessarily “ paradigm ” shifts, but are at least candidates – History will judge which are true shifts The initial paradigm Example Paradigm Shifts • Batch processing • Batch processing • Time-sharing Interactive computing Impersonal computing 1

Example Paradigm Shifts Example Paradigm Shifts • Batch processing • Batch processing @#$% ! C…P… filename Move this file here, • Timesharing • Timesharing dot star… or was and copy this to there. it R…M? • Networking • Networking • Graphical displays % foo.bar ABORT ??? dumby!!! Direct manipulation Community computing Example Paradigm Shifts Example Paradigm Shifts • Batch processing • Batch processing • Timesharing • Timesharing • Networking • Networking • Graphical display • Graphical display • Microprocessor • Microprocessor • WWW Global information Personal computing Example Paradigm Shifts Time-sharing • Batch processing • A sym biosis of physical • 1940s and 1950s – explosive technological and electronic worlds in growth • Timesharing service of everyday activities. • Networking • 1960s – need to channel the power • Graphical display • Microprocessor • J.C.R. Licklider at ARPA • WWW • Ubiquitous • single com puter supporting m ultiple users Computing 2

Video Display Units Programming toolkits • m ore suitable medium than paper • Engelbart at Stanford Research Institute • 1962 – Sutherland's Sketchpad • 1963 – augmenting man's intellect • computers for visualizing and manipulating • 1968 NLS/ Augment system demonstration data • the right programming toolkit provides • one person's contribution could drastically building blocks to producing complex change the history of com puting interactive system s Window systems and the Personal computing WIMP interface • 1970s – Papert's LOGO language for simple • humans can pursue more than one task at a graphics programming by children tim e • A system is m ore powerful as it becom es • windows used for dialogue partitioning, to easier to user “change the topic” • Future of computing in small, powerful • 1981 – Xerox Star first commercial windowing machines dedicated to the individual system • Kay at Xerox PARC – the Dynabook as the • windows, icons, menus and pointers now ultim ate personal com puter fam iliar interaction m echanism s Metaphor Direct manipulation • relating computing to other real-world activity • 1982 – Shneiderman describes appeal of is effective teaching technique graphically-based interaction – LOGO's turtle dragging its tail – visibility of objects – file m anagem ent on an office desktop – increm ental action and rapid feedback – word processing as typing – reversibility encourages exploration – financial analysis on spreadsheets – syntactic correctness of all actions – virtual reality – user inside the m etaphor – replace language with action • 1984 – Apple Macintosh • Problem s • the model-world metaphor – som e tasks do not fit into a given m etaphor – cultural bias • What You See Is What You Get (WYSIWYG) 3

Language versus Action Hypertext • actions do not always speak louder than • 1945 – Vannevar Bush and the memex words! • key to success in managing explosion of • DM – interface replaces underlying inform ation system • language paradigm • m id 1960s – Nelson describes hypertext as non-linear browsing structure • interface as mediator • interface acts as intelligent agent • hypermedia and multimedia • programming by example is both action • Nelson's Xanadu project still a dream today and language Computer Supported Multimodality Cooperative Work (CSCW) • a mode is a human communication • CSCW removes bias of single user / channel single computer system • Can no longer neglect the social aspects • emphasis on simultaneous use of multiple channels for input and output • Electronic mail is most prominent success The World Wide Web Agent-based Interfaces • Hypertext, as originally realized, was a • Original interfaces – Com m ands given to com puter closed system – Language-based • Simple, universal protocols (e.g. HTTP) • Direct Manipulation/ WIMP and mark-up languages (e.g. HTML) – Com m ands perform ed on “ world” representation made publishing and accessing easy – Action based • Critical mass of users lead to a • Agents - return to language by instilling proactivity and “intelligence” in com m and complete transformation of our processor information economy. – Avatars, natural language processing 4

Sensor-based and Context- Ubiquitous Computing aware Interaction “The most profound technologies are those that • Humans are good at recognizing the disappear.” “context” of a situation and reacting Mark Weiser, 1991 appropriately • Automatically sensing physical Late 1980’s: computer was very apparent phenomena (e.g., light, temp, location, identity) becoming easier How to make it disappear? • How can we go from sensed physical – Shrink and em bed/ distribute it in the physical world measures to interactions that behave as – Design interactions that don’t dem and our intention if made “aware” of the surroundings? 5