D S R G. Alina Mashko. User interface. Department of vehicle technology. Faculty of Transportation Sciences

Transcription

1 User interface Alina Mashko Department of vehicle technology Faculty of Transportation Sciences Czech Technical University in Prague

2 HCI design process 4 Basic steps

3 Step 1 What is wanted Study of market of existing alternatives, preceding versions, etc. Focus groups, interviews, brainstorming, questionnaires. QFD analysis. State of the art research.

4 Steps 2-3 Step 2 Formulation of system purpose and functions (what should it do) Its functioning in various scenarios, response to various scenario events Evaluation Step 3 Design recommendations per system purpose (functions and human response to it) System prototype and testing Steps 2 and 3 is often a cycloid process till goal design is achieved

5 Step 4 System design implementation and realization System architecture Integration Specifications and technical documentation

6 GUI design requirements Intuitive Learnable (quickly) to use Least surprise principle Behavior per user expectations Icons appearance Sequence of procedures Intuitive can be tricky in some specialized programs. Which one is more intuitive for you?

7 GUI elements and functions Button is the most popular GUI element Feedback to user actions via GUI elements e.g.: item highlighting, button click visual, blink, text notification Non-GUI elements of interface feed: sound signal, vibration. Examples Send text with ENTER (or OK button) Checkbox for item selection Selection list Driving Simulation Research Group FTS-CTU

8 Dashboard GUI elements

9 GUI design requirements (contd.) Simple (isn t overloaded with unnecessary information, visuals) Complete (It lets the user do everything that the program is capable of doing) ISO 9241, Ergonomics of Human System Interaction, adopts traditional usability categories with specific measures.

10 Cluttered interface example

11 Find current population of US 86% of users failed (

12 Last generation cluster

13 New generation cluster

14 Examples

15 Problems of interaction

16 A persona design approach Is based on prototypical, composite, hypothetical users. Prototypical includes basic user characteristics Composite comprises characteristics of a group of users Hypothetical imagining (drawing a portrait) possible situation of a particular user (not the designer!)

17 A scenario approach Sequences of typical events/tasks Deploy emergency events (e.g. system failure, user failure)

18 Hierarchical task analysis Starts from overall goal and breaks down into numbered sub-goals

19 Evaluation/assessment Who is giving this feedback? Typical user, member of target group, a fellow etc. When are you getting this feedback? On an early prototype or an established product? How has this evaluation been arrived at? As compared to guidelines or from simulation, or from use in a realistic context What has been used as a measure? Quantitative (eg. time to complete task, error rate) Qualitative (ease of use ratings) Compared to recommendations or alternatives Consistency

20 Evaluation Analytical evaluation (by experts) Cognitive walkthrough (evaluation by experts based on user set of questions) (e.g. Polson, 1992) Heuristic evaluation - evaluated by experts compliance with usability principles (e.g. Nielsen & Molich) Model-based evaluation (e.g. GOMS) Usability testing (controlled conditions) Hypothesis test Field studies (natural conditions)

21 Analytical (heuristic) evaluation (Nielsen, 1992)

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23 Digital design

24 ??? Why did it fail? What did it fail to notify about? Why am I seeing this? Source: About Face 3: The Essentials of Interaction Design, Third Edition Why do I need to ok this?

25 Interface design principles User interfaces designed by engineers follow the implementation model (eg.: switch between DVD and TV, mowing within/between drive in Windows) The goal of interface design is to shield users from implementation model. Eg.: Users don t understand Boolean Algebra

26 from Mechanical to Information/digital New technology demands new representations. (Example: phone) Mechanical-Age representations degrade user interaction. (Eg.: typing an individual address on an envelope using a computer) Design principles: - Don t replicate Mechanical-Age artifacts in user interfaces without Information-Age enhancements. - Significant change must be significantly better.

27 Examples: digital calendar Good or bad?

28 Users User demands depend on experience Most users are intermediates

29 Design principles Nobody wants to remain a beginner Imagine users as very intelligent but very busy. Design for different intelligence levels

30 Research Qualitative Stakeholder interviews Subject matter expert (SME) interviews User and customer interviews User observation/ethnographic field studies Literature review Product/prototype and competitive audits

31 User interviews Avoid a fixed set of questions Ask goal-oriented questions Ask system-oriented questions Ask workflow-oriented questions Ask attitude-oriented questions Focus on goals first, tasks second Avoid making the user a designer Avoid discussions of technology Encourage storytelling Ask for a show and tell Avoid leading questions

32 Personas approach Try to design an automobile that pleases every possible driver, you end up with a car with every possible feature, but that pleases nobody. Software today is too often designed to please too many users, resulting in low user satisfaction.

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34 Partially based on: Avoid leading questions, by Alan Cooper (Author), Robert Reimann (Author), David Cronin (Author)