Chapter 7 Overview

• Metaphors – verbal metaphors – interface metaphors • Ubiquitous computing • Conceptual models – user’s models, design models, system image

Metaphor

A figure of speech in which a term is transferred from the object it ordinarily designates to one it can designate only by implicit comparison or analogy, as in the phrase evening of life.

conveys an abstract concept in a more familiar and accessible form Verbal Metaphors

• Knowledge about a familiar domain in terms of elements and their relation to each other is mapped onto elements and relations in an unfamiliar domain • Example: typewriters and word processors – Elements: keyboard, spacebar, return key, ... – Relations: only one key at a time, hitting a key results in a character display, ... • Dissimilarities also are present – once users are aware of discrepancies and differences they can develop a new mental model

Verbal Metaphors

• Verbal metaphors can be useful tools to help new users understand a new system – explicitly providing a verbal metaphor in training – but also needs to describe aspects of the system as a computer system. Need to incorporate aspects of the system’s structure and function. Interface Metaphors

• Combine a familiar domain with the system structure to make a concrete system image • Beyond use of verbal metaphor as training tool; creates electronic counterparts to physical objects • Interface metaphor is the model that is learned • Example: Star and the • Issue: incorporating functionality that is not part of the interface metaphor

Composite interface metaphors

• Composite metaphors: desktop metaphor combined with other metaphors. – example: scroll bar – menus –windows • Represent multiple mental models • Potential problem: conceptual mismatch between previous knowledge and interface object behavior – “tearing” sheets of paper off of a notepad – but can lead to developing more elaborate mental models Metaphors for application areas

• Operating environment – desktop • Spreadsheets – ledger sheet • Multimedia environments – Rooms

Ubiquitous computing

• “Invisibly enhancing the world that already exists” • Unconscious and effortless tool use • Enabling technology: active badges • Application technology: “invisible computers” Ubiquitous Computing

"Ubiquitous computing names the third wave in computing, just now beginning. First were mainframes, each shared by lots of people. Now we are in the personal computing era, person and machine staring uneasily at each other across the desktop. Next comes ubiquitous computing, or the age of calm technology, when technology recedes into the background of our lives." --Mark Weiser

Ubiquitous Computing

• Scenario: http://www.ubiq.com/hypertext/weiser/SciAmDraft3.html • Ubiquitous computing: http://nano.xerox.com/hypertext/weiser/UbiHome.html • Ubiquitous computing versus virtual reality: http://www.ubiq.com/hypertext/weiser/VRvsUbi.gif • Mark Weiser: http://www.ubiq.com/hypertext/weiser/ Conceptual models

• The ways in which systems are conceptualized and understood by different people – system users (user model) – system designers (design model) • User’s model, design models, system image

User’s model, Design model, System image

Design User’s Model Model

Designer User

Documentation System System Image