User-Centred Design: Design Principles (lecture-4) Prof. Dr. Matthias Rauterberg Faculty Industrial Design Technical University of Eindhoven

© M. Rauterberg, TU/e2 The first most important invariant horizon –the horizon is always lighter than the ground ground –the ground is always darker than the horizon

© M. Rauterberg, TU/e3 The second most important invariant The Top –All good, strong and important things are at the top (e.g., God in heaven, the king, the boss, etc.). The Bottom –All small, weak and unimportant things are at the bottom line.

© M. Rauterberg, TU/e4 Limits of the Working Memory working memory –remember time < 5 sec –about 5-9 chunks –masking –interferences long-term memory –no capacity limits

© M. Rauterberg, TU/e5 Knowledge in the World and in the Head

© M. Rauterberg, TU/e6 The Difference between Internal and External Memory the mental model of the user about the external world is always incomplete all necessary information which is not in the internal memory must be provided by the environment (the “external memory”)

© M. Rauterberg, TU/e7 The Concept of Natural Mappings Definition [see Norman, D., 1988, p. 75ff]: –A design solution based on a natural mappings reduces the need for additional explanatory information in memory! –Natural mappings guarantee a minimum number of cognitive transformation steps. –If a design depends upon labels, it may be faulty. Labels are important and often necessary, but the appropriate use of natural mappings can minimize the need for them. Wherever labels seem necessary, consider another design!

© M. Rauterberg, TU/e8 Design of Light Switch Panels (1) Problem: –no direct mapping between switches and corresponding lamps

© M. Rauterberg, TU/e9 Design of Light Switch Panels (2)

© M. Rauterberg, TU/e10 Corrective Design (1) Problem: –sliding door can damage the open petrol flap

© M. Rauterberg, TU/e11 Corrective Design (2) Solution: –extra bar to lock the sliding door

© M. Rauterberg, TU/e12 Design of Door Handles

© M. Rauterberg, TU/e13 Design of Shower Faucets Natural mapping: –hot water left side or RED –cold water right side or BLUE Un-natural mapping: –something else (see figure)

© M. Rauterberg, TU/e14 Natural Mapping (1)

© M. Rauterberg, TU/e15 Natural Mapping (2)

© M. Rauterberg, TU/e16 Double Design Water-tap with –normal screw caps plus –infrared sensor for automatic opening

© M. Rauterberg, TU/e17

© M. Rauterberg, TU/e18 The most important design principle Perception Space –The physical space where the user’s attention is. Action Space –The physical space where the user acts in. Design Principle: –perception space and action space must coincide!

© M. Rauterberg, TU/e19 Design of Stove Controls (1)

© M. Rauterberg, TU/e20 Design of Stove Controls (2)

© M. Rauterberg, TU/e21 Interactive Directness: the desktop example Pull down menus Toolbar

© M. Rauterberg, TU/e22 action space perception space

© M. Rauterberg, TU/e23 Head-up Displays in Cars More information and less distraction Information on the state of the road, on the speed of the vehicle in front (supplied by the intelligent cruise control), on obstacles lying around the next bend in the road identified by the remote detection system, or direction arrows sent by the driver guidance system... drivers will be receiving more and more information from "intelligent" vehicle systems. Although the information is intended to enhance safe driving, there is a danger that an abundance of information may produce the opposite effect if driver glance-away time has to increase in order to apprehend the data.

© M. Rauterberg, TU/e24 Electronic Performance Support System Food processing plant worker with a first-generation prototype wearable computer. Possible applications include support for quality control data collection or assistance with environmental auditing. This system gives its users the information the users need to perform a task as they actually perform the task.

© M. Rauterberg, TU/e25 Airline Applications This remarkable ultra-lightweight computer, worn as a belt, delivers maximum information to users with a minimum of work. Designed for individuals who demand mobility, this computer offers voice control and heads up display for complete, hands-free operation. Users can enter or retrieve information while going about their jobs, instead of constantly returning to the shop area to check a stationary computer, or stopping work to punch keys.

© M. Rauterberg, TU/e26 Interlacing display and manipulation spaces Exercise-4: –Design a user interface for a computer system with some of the following components: input devices: joystick, graphic tablet with pen, keyboard, mouse, video camera, touch screen ouput devices: monitor, video projector other components: semitransparent mirrors

© M. Rauterberg, TU/e27 Two design principles for natural user interfaces (NUIs): No technical equipment inside to body space of the user! 2. design principle Perception space and action space must coincide! 1. design principle

© M. Rauterberg, TU/e28

© M. Rauterberg, TU/e29 The Virtual Workbench The KOSIMA project at the TU Aachen

© M. Rauterberg, TU/e30 virtual player real chip virtual chips overhead projector video camera NEW button NUI (1): The Digital Playing Desk

© M. Rauterberg, TU/e31 Digital Playing Desk: Playing time per game

© M. Rauterberg, TU/e32 Digital Playing Desk: winning chance per dialog technique computer win remis user win Cell Line Chart for "winning chance" Grouping Variable(s): Interface type Error Bars: ± 1 Standard Deviation(s) CIMITIDPD P<.001P<.080P<.020 P<.802 P<.001 P<.007

© M. Rauterberg, TU/e33 NUI (2): a team oriented planning tool

© M. Rauterberg, TU/e34 NUI (2): The Build-It System

© M. Rauterberg, TU/e35 Build-It System: the interaction handler

© M. Rauterberg, TU/e36 BUILD-IT: an integrative design tool design team with different domain knowledge unconstrained social interaction integration of form and content intuitive interaction style

© M. Rauterberg, TU/e37 Actual research goals... hand-written input speech input two-handed interaction new methods and concepts for integrative design