CSC USI Class Meeting 4 September 13, 2006

Notations for Actions Actions for a keyboard and graphical input device (GID) include:  Tap: pressing and immediately releasing a key. Implemented with a momentary contact (spring-loaded) switch.  Click: Position the GID and tap the GID button.  Double click: Position the GID and tap the GID button twice quickly, without repositioning.

Notation for Actions (2)  Keystroke Level Model –K[ ], a keystroke. E.g. K[b] means tapping lower case b –P, pointing. E.g. positioning the GID –H, homing. E.g. moving from keyboard to GID or GID to keyboard –M, mental processing –R, responding

Notations for Action (3)  What does the description To create a right justified paragraph, use Control +. ask you to do?

Notations for Action (4) More actions:  Press and hold a key  Release a key –But on what signal or input?

Notations and Actions (5)  Raskin/Beck –Press and hold: b  –Release: b  –Tap: b  b , shortened to b  or just b –Release on signal: b  [ ] –Note that key names are italicized  Examples: –Create an upper case M: Shift  m  m  Shift , shortened to Shift  m 

Notations for Action (6)  Examples (continued) –Distinguish between Enter and E n t e r Enter is the name of a key and E n t e r is short for E  n  t  e  r  –b  [20] gives a string of bs –Ctrl  Alt  Del  brings up the Task Manager

Clock Setting  Set the clock one hour earlier, the common action at the end of daylight savings time.  GOMS model –Goal: stated above –Operations: –Methods: –Selection Rule:

Bad Interfaces  Detectable with GOMS model?

Interfaces and Widgets What can a user do? When? Where? How effectively?  Catalog of interface actions  Catalog of interface widgets

Modeling Actions  Task analysis: temporal issues  GOMS analysis: method issues  Keystroke level: operator issues

Task Analysis  Describes the process the user chooses to reach a goal in a specific domain  Hierarchical description, typically  Task modeling systems –GOMS (?) –ConcurTaskTrees –UAN (User Action Notation)

Research Project  Hypotheses (tonight)  Independent variables (tonight)  Dependent variables (tonight)  Bibliography (next week)  Background  Formal setting (let’s talk)

Theory Collection Visual processing  Three-stage visual system  Preattentive processing theory  Structured object perception theory (Biederman)  Scientific color theory (CIE)

Theory Collection (2) Motor Behavior Models  Hick-Hyman Law: choice time  Keystroke-Level Model: error-free task completion time  Three-state model of graphical input (Buxton)  Fitts’ Law: human movement  Guiard’s Model of Bimanual Skill

Theory Collection (3) Task analysis  Hierarchical model using ConcurTaskTrees ConcurTaskTrees

Research Project (2)  Experimental design –Between subjects –Within subjects  Sources of bias  Sources of subjects  Logic of conclusions

Research Project (3)  Institutional Review Board (IRB)  IRB form  Informed consent

Research Project (4)  Short presentation –One spokesperson –Five minutes –Hypothesis, variables, initial experimental design –PowerPoint or transparencies

Next Time  Read Carroll, Chapter 6. Note that this chapter describes several “spaces.”  Create a concept map that shows the relationships between these “spaces.” Make sure your map is labeled with your name so that it can be submitted.  Submit a revised IRB form and bibliography.  Research project presentation

Research Team Meetings