Unit 2: interaction design. 2.1 Models of Interaction. Models of Interaction. Why To identify the likely root of difficulties As a framework to compare different interaction styles Terms of interaction. Norman’s Execution-Evaluation Cycle. Gulf of evaluation. Light-switching example.
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Models of Interaction • Why • To identify the likely root of difficulties • As a framework to compare different interaction styles • Terms of interaction
Norman’s Execution-Evaluation Cycle Gulf of evaluation Light-switching example Gulf of execution http://www.it.bton.ac.uk/staff/rng/teaching/notes/NormanGulfsC.GIF
Gulf of Execution • VCR programmed recording • VCR’s language • Hit the record button. • Specify time of recording via the controls • Select channel via the channel-up-down control. • Press the OK button. • User’s mental model • Hit the record button.
Gulf of Evaluation Security permission Non-linear check-out
Class Discussion • Amanda跟先生之間喜歡使用密語 • 他們以動物相互稱呼對方 • 即使在skype中，也模仿動物的叫聲 • Amanda: OrrrrrrrrrYiiiiiiYooooooo • Amanda’s husband: KoKo~KoKo~ • 某天，在Amanda先生在skype中看到： • Amanda: 在嗎? • 此訊息可能導致Amanda先生出現何種鴻溝?
Norman’s Execution-Evaluation Cycle • As a problem classifier • Amanda發現iBon的螢幕反光很嚴重 • Bob想要訂NBA熱身賽門票卻找不到位置 • Carol列印收據時找不到收據 • Clear and intuitive model • Only consider interface • Over-emphasize the user’s view
Poor Mapping In Articulation • Coverage (input/task) • Relative ease of translation
Different Articulation Effects of the Same Input Language Good mappingfor moving files Not-So-Good mapping for re-naming file extension in batch
Poor Mapping in Performance Disappeared shutdown? • Coverage (input language/core language) • Relative ease of translation
Class Discussion: Poor Mapping in Performance? Cannot shutdown remote PC Press Alt+F4
Poor Mapping in Observation What time is it? HTML editing in Notepad • Coverage (output/task) • Relative ease of translation
Designing Interactive Systems vs.Interaction Design • What a centralized stapler can change?
What is Design • Goal • Constraints • Trade-off • Good decision making • Creative solution
The Golden Rule of Design—Understand Your Material Design Chair A Using Chair B’s design? The materials for HCI?
Human Errors Slips Mistakes
2.4 Usability Metrics as Benchmarks What is wanted Analysis Design Evaluation
Sample Usability Specification Now level vs. Worse case
Usability Engineering • Early inclusion of usability in the SDLC • Explicit usability metrics in requirements spec. • Empirical evidence • Limitations • Only physical interactions observed • Usability ?= usability specification
2.5 Scenarios What is wanted Analysis Design Evaluation
Detailed Scenario Example: Proposed Scenario for Movie Player (1/3) • Brian would like to see the new ﬁlm Moments of Signiﬁcance and wants to invite Alison, but he knows she doesn’t like ‘arty’ ﬁlms. • He decides to take a look at it to see if she would like it and so connects to one of the movie-sharing networks. • He uses his work machine as it has a higher bandwidth connection, but feels a bit guilty.
Detailed Scenario Example: Proposed Scenario for Movie Player (2/3) • He knows he will be getting an illegal copy of the ﬁlm, but decides it is OK as he is intending to go to the cinema to watch it. • After it downloads to his machine he takes out his new personal movie player. • He presses the ‘menu’ button and on the small LCD screen he scrolls using the arrow keys to ‘bluetooth connect’ and presses the ‘select’ button.
Detailed Scenario Example: Proposed Scenario for Movie Player (3/3) • On his computer the movie download program now has an icon showing that it has recognized a compatible device and he drags the icon of the ﬁlm over the icon for the player. • On the player the LCD screen says ‘downloading now’, with a percent done indicator and small whirling icon.