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CSC 8570 -- USI. Class Meeting 8 November 1, 2005. Important Concepts. Models of physical action: Fitt’s Law, Hick’s Law, Keystroke Level Model GOMS model, in various forms Cognitive dimensions of notation What makes a good interface? Who says? GUEPs Mental models, in various forms.
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CSC 8570 -- USI Class Meeting 8 November 1, 2005
Important Concepts • Models of physical action: Fitt’s Law, Hick’s Law, Keystroke Level Model • GOMS model, in various forms • Cognitive dimensions of notation • What makes a good interface? Who says? • GUEPs • Mental models, in various forms
Important Concepts (2) • Applied perception • How humans perceive their surroundings • Usability models • That metrics for interfaces exist • Simple interfaces are best • Making better concept maps
Confusions – Mental Models • As theories • How one believes a system works, e.g. an ATM machine, a history list • As problem spaces • A set of partial solutions to a problem with transitions from one partial solution to the next, e.g. the “screen shots” as you solve a Sudoku puzzle
Mental Models (2) • As homomorphisms of the physical world • An analog picture of a description from which inferences may be drawn • Derived from language, perception, or imagination • The image, or pictorial context, drawn from a textual description
Mental Models (3) • As representations of representational artifacts (yoked state space) • A combination of the goal space and the operations available to transform the elements of the goal space. The model one uses when editing text or creating a webpage in a text editor.
Mental Models (4) • As computationally equivalent to external representations (internalization)
Confusions – GOMS • Match GOMS to the problem space view of a mental model • Compare GOMS and the KLM for a system • Develop two or three clear examples • Clock setting • Route discovery • POS credit card payment
Confusions – Others • Cognitive dimensions • Models and frameworks in general • Which are better • Which are more important • Three-stage visual model • Preparing for the exam
Button Experiment • Button syntax • Notation • Button semantics • Notation • Properties of buttons • Button class • Cognitive dimensions of the button • GUEPs supported/violated by the button
Interface Evaluation Models and techniques • GOMS analysis • Keystroke Level Model • Cognitive dimensions of notation • Hierarchy of design principles • Task analysis • Layout appropriateness
Interface Evaluation (2) Measurements • Time • Counts • Geometry • Satisfaction
Interface Evaluation (3) Musike Scoring System • Developed for menu-based systems • Modified for web pages • Provides weighted sum of scores of individual factors • Each individual factor to be based on a measurable design principle
Example -- AWSP • Evaluates web sites • Based on Jakob Neilsen’s design principles • Rewritten by Lea Taylor
AWSP Definitions • Above the Fold: The first screen content that is visible without scrolling • Examples: Content that provides insight into the results of following a link • External Ads: Ads for companies or organizations other than the focus of the current website
AWSP Definitions (2) • Liquid Layout: Layout that allows the text to adjust to the size of the available space • Widget: A simple interface feature such as a dropdown menu or a text box
www.allentownpa.org www.altoonapa.gov www.arnoldpa.org www.bethlehem-pa.gov www.cityofduquesne.com www.yorkcity.org www.cityoferiepa.com www.franklinpennsylvania.net www.harrisburgpa.gov www.cityoflancasterpa.com www.mckeesport.org www.newcastlepa.org www.cityofreadingpa .com www.cityofwilliamsport.org Web Site Assignment
Next Time • Read Carroll, Chapter 10. • Create concept map for Chapter 10