Introduction - Lecture 1 - Human-Computer Interaction (1023841ANR)

This lecture forms part of the course Human-Computer Interaction given at the Vrije Universiteit Brussel.

Transcript

1. Human-Computer Interaction Introduction, History and Interface Types Prof. Beat Signer Department Vrije beatsigner.com Universiteit of Computer Brussel Science Department of Computer Science Vrije Universiteit Brussel beatsigner.com 2 December 2005
2. Course Organisation ▪ Prof. Dr. Beat Signer Vrije Universiteit Brussel PL9.3.60 (Pleinlaan 9) +32 2 629 1239 bsigner@vub.be wise.vub.ac.be/beat-signer A close-up of a person smiling Description automatically generated ▪ Ingela L. Rossing Vrije Universiteit Brussel PL9.3.56 (Pleinlaan 9) +32 2 629 3749 ingela.rossing@vub.be wise.vub.ac.be/ingela-rossing September 21, 2026 Beat Signer - Department of Computer Science - bsigner@vub.be 2
3. Course Organisation … ▪ Bingyan Li Vrije Universiteit Brussel PL9.3.58 (Pleinlaan 9) +32 2 629 3487 bingyan.li@vub.be wise.vub.ac.be/bingyan-li September 21, 2026 Beat Signer - Department of Computer Science - bsigner@vub.be 3
4. Course Goals ▪ After attending the course Human-Computer Interaction, the student has an understanding of general HCI principles and user interface design guidelines as well as the interaction design process and its use for the humancentred design of digital and physical products. The student is able to reflect on the qualities and shortcomings of different interaction styles, while placing the user at the core of the interface design process. September 21, 2026 Beat Signer - Department of Computer Science - bsigner@vub.be 4
5. Course Goals … ▪ The student can apply the theoretical background, the human-computer interaction principles and the interaction design lifecycle model discussed in the course to create interfaces with good usability and user experience. Students are further able to explain their decisions based on the theory as well requirements analysis and evaluations. ▪ The student is able to assess the usability and effectiveness of user interfaces by using the tools and principles studied during the course. Based on these tools and principles, the student is further able to match different interface and interaction types for a given context. September 21, 2026 Beat Signer - Department of Computer Science - bsigner@vub.be 5
6. Exercises ▪ The course content is further investigated in the exercise sessions ▪ the topics covered in the exercise sessions will also be helpful for the assignment ▪ Additional content might be covered in exercises strongly recommended to attend all exercise sessions! ▪ exam covers content of lectures and exercises ▪ ▪ Exercise sessions assistants: Ingela Rossing (ingela.rossing@vub.be) and Bingyan Li (bingyan.li@vub.be) ▪ 3 groups (starting on September 21) ▪ - WPO1: Thursday 11:00–13:00 in D.3.05, WPO2: Wednesday 14:00–16:00 in D.2.18 and WPO3: Thursday 16:00–18:00 in D.2.14 September 21, 2026 Beat Signer - Department of Computer Science - bsigner@vub.be 6
7. Course Material ▪ All material will be available on Canvas ▪ lecture slides, exercises, research papers, tutorials, ... ▪ Make sure that you are subscribed to the Human-Computer Interaction course on Canvas ▪ https://canvas.vub.be/courses/49809 ▪ Handouts are on Canvas the day before the lecture ▪ slides will also be available on the WISE website - https://wise.vub.ac.be/course/human-computer-interaction September 21, 2026 Beat Signer - Department of Computer Science - bsigner@vub.be 7
8. Lecture Schedule 2 3 4 5 6 7 8 Lecture 1: Introduction, History and Interface Types G.1.53 Exercise 1: Discussion of Existing Interfaces and Interactions D.3.05/D.2.18/D.2.10 Lecture 2: HCI and Interaction Design G.1.53 Exercise 2: Requirements Analysis D.3.05/D.2.18/D.2.14 Lecture 3: Requirements Analysis and Prototyping G.1.53 No Exercise Lecture 4: Human Perception and Cognition G.1.53 Exercise 3: Low-Fidelity Prototyping D.3.05/D.2.18/D.2.14 Lecture 5: Design Guidelines and Models G.1.53 Exercise 4: Mid-Fidelity Prototyping (FIGMA) and Design Validation D.3.05/D.2.18/D.2.14 Lecture 6: Evaluation Methods G.1.53 No Exercise D.2.23 E.1.02 Lecture 7: HCI Research Methods P2.0.05 Exercise 5: Project Feedback (Low-Fidelity Prototype) D.3.09/D.2.18/D.2.14 September 21, 2026 Beat Signer - Department of Computer Science - bsigner@vub.be 8
9. Lecture Schedule … 9 10 11 12 13 14 No Lecture Exercise 6: Heuristic Evaluation D.3.09/D.2.14 No Lecture Exercise 7: Evaluation (Usability / User Experience) D.2.18/D.2.14 No Lecture Exercise 7 for some Groups D.3.09/D.2.18 No Lecture No Exercise Lecture 8: Use Cases and Course Review G.1.53 No Exercise No Lecture Exercise 8: Project Presentation September 21, 2026 D.3.09/D.2.18/D.2.18 Beat Signer - Department of Computer Science - bsigner@vub.be 9
10. Assignment ▪ New applications for Brussels /Belgium ▪ you will design one of five different applications (Event Calendar Organiser, Brussels International Students, Brussels Chocolate Exploration, VUB Cafeteria App or Active Senior Gatherings) - project report, videos of prototypes and final presentation - evaluated based on creativity, application of Interaction Design process and HCI guidelines, documentation, requirements analysis and evaluation, prototypes and final presentation ▪ Assignment handed out in week 3 ▪ group project with 4 students per group - add yourself to a group on Canvas (under People) or send an email to Ingela Rossing by Friday, October 2 (ingela.rossing@vub.be) - final presentation (week of December 14), report and videos (December 23) ▪ assignment counts for 50% of the final grade September 21, 2026 Beat Signer - Department of Computer Science - bsigner@vub.be 10
11. Exam ▪ Written closed book exam covers content of lectures and exercises ▪ counts 50% for the overall grade ▪ ▪ Overall grade = written exam (50%) + assignment (50%) for the assignment students have some flexibility in distributing the grades (±2 points) ▪ note that the grade for the written exam as well as for the assignment have to be 8/20 or higher in order to pass the exam! ▪ September 21, 2026 Beat Signer - Department of Computer Science - bsigner@vub.be 11
12. Plagiarism and Use of GenAI ▪ The use of Generative AI (GenAI) is strictly limited to enhancing the clarity and readability of your written work. You may use it for grammar correction, sentence restructuring, and improving the flow of text. All project work must reflect your own original thought process and problem-solving skills. Any unauthorised use of GenAI beyond the above-mentioned permitted use will be considered a violation of academic integrity. Further, if GenAI has been used, this should be declared. ▪ Check slides from Plagiarism and GenAI Info Session ▪ https://canvas.vub.be/courses/30881/modules/items/713134 September 21, 2026 Beat Signer - Department of Computer Science - bsigner@vub.be 12
13. Course Outline 1. Introduction history of human-computer interaction ▪ interface types ▪ 2. HCI and Interaction Design human-computer interaction, interaction design process ▪ understanding and conceptualising interaction ▪ 3. Requirements Analysis and Prototyping data gathering and analysis for requirements ▪ different types of prototyping ▪ 4. Human Perception and Cognition vision, attention, recognition, memory, … ▪ hand-eye coordination ▪ September 21, 2026 Beat Signer - Department of Computer Science - bsigner@vub.be 13
14. Course Outline … 5. Design Guidelines and Models 6. Evaluation Methods ▪ DECIDE framework, usability testing, experiments, field testing, heuristic evaluations, A/B testing, predictive models 7. HCI Research Methods 8. Use Cases and Course Review various use cases ▪ course review and questions about exam ▪ September 21, 2026 Beat Signer - Department of Computer Science - bsigner@vub.be 14
15. Human-Computer Interaction Human-computer interaction is a discipline concerned with the design, evaluation and implementation of interactive computing systems for human use and with the study of major phenomena surrounding them. ACM SIGCHI Curricula for Human-Computer Interaction ▪ Human-Computer Interaction is a multidisciplinary field Computer Science ▪ Design ▪ Cognitive Science ▪ Psychology ▪ … ▪ September 21, 2026 Beat Signer - Department of Computer Science - bsigner@vub.be 15
16. Beyond Human-Computer Interaction Interaction design addresses the design of interactive products to support the way people communicate and interact in their everyday and working lives. Y. Rogers, H. Sharp and J. Preece, Interaction Design: Beyond Human-Computer Interaction Interaction Design (IxD) defines the structure and behavior of interactive systems. Interaction Designers strive to create meaningful relationships between people and the products and services that they use, from computers to mobile devices to appliances and beyond. ixd.org September 21, 2026 Beat Signer - Department of Computer Science - bsigner@vub.be 16
17. Interaction Design (IxD) [Illustration by Dan Saffer] September 21, 2026 Beat Signer - Department of Computer Science - bsigner@vub.be 17
18. Analogue Computers ▪ Focus on technology and not on human-machine interaction (HMI) ▪ Only trained engineers could use the machines ▪ Interaction was limited to the programming of the machines (e.g. punched cards) and the printing of results September 21, 2026 Beat Signer - Department of Computer Science - bsigner@vub.be 18
19. Sketchpad (1963) ▪ Sketchpad developed as part of Ivan Sutherland’s PhD thesis at MIT drawing tool ▪ light pen and buttons ▪ first graphical user interface ▪ direct manipulation of graphical objects ▪ basis for many new interface ideas ▪ September 21, 2026 Beat Signer - Department of Computer Science - bsigner@vub.be 19
20. The Mother of All Demos (1968) ▪ Douglas Engelbart and his colleagues at the Stanford Research Institute developed the oNLine System (NLS) as part of the Augment Project ▪ vision about the future of interactive computing ▪ NLS was demonstrated at the Fall Joint Computer Conference in 1968 Douglas Engelbart showed first practical use of hypertext ▪ computer mouse ▪ remote collaboration (connected computers) ▪ raster-scan video monitors ▪ screen windows ▪ ... ▪ September 21, 2026 Beat Signer - Department of Computer Science - bsigner@vub.be 20
21. NLS Demo September 21, 2026 Beat Signer - Department of Computer Science - bsigner@vub.be 21
22. Xerox Alto (1973) and Xerox Star (1981) ▪ Personal workstation ▪ LAN to share resources ▪ Desktop metaphor ▪ ▪ ▪ ▪ windows, icons, menus, pointer (WIMP) interaction "filing cabinets" with hierarchical folders seeing and pointing rather than remembering and typing "What You See Is What You Get" (WYSIWYG) Xerox Star 8010 [http://www.digibarn.com/collections/systems/xerox-8010/] September 21, 2026 Beat Signer - Department of Computer Science - bsigner@vub.be 22
23. Apple Macintosh (1984) ▪ Successor of Apple Lisa ▪ ▪ corrected some mistakes aggressive pricing ▪ Old ideas (e.g. Xerox Star) but well executed ▪ Domination in the desktop publishing sector ▪ ▪ excellent graphics affordable laser printers September 21, 2026 Beat Signer - Department of Computer Science - bsigner@vub.be 23
24. "Evolution" of Interfaces original Macintosh Mac Studio comparison date January 1984 January 2026 +42 years price $2500 $5598 × 2.24 CPU 68000 Motorola 8 MHz 0.7 MIPS 32(80)-core M3 Ultra 4.06 GHz 28.63 TFLOPS × 508 × 40 900 000 memory 128 kB 96 GB × 750 000 storage 400 kB floppy drive 1 TB SSD drive × 2 684 000 monitor 9" black and white 512 x 342 68 dpi 27" colour 5120 x 2880 218 dpi ×3 × 84 × 3.2 devices mouse keyboard mouse keyboard same same GUI desktop WIMP desktop WIMP same [partly based on Beaudouin-Lafon 2004] September 21, 2026 Beat Signer - Department of Computer Science - bsigner@vub.be 24
25. Recent Changes and Opportunities in HCI ▪ Advances in graphical interfaces, speech, gesture and handwriting recognition, and artificial intelligence ▪ Emergence of the Internet, cell phones, wireless networks, sensor technologies, large and small screens, or virtual and augmented reality hardware innovative interaction with digital information and services ▪ combining the physical and digital in new ways ▪ - mixed reality, cross-media technologies, tangible interfaces, wearable computing, ... ▪ collaborative interfaces with social interaction September 21, 2026 Beat Signer - Department of Computer Science - bsigner@vub.be 25
26. Interface Types ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ Command-based WIMP and GUI Virtual reality Web Consumer electronics Mobile Speech (Voice) Pen Touch Gesture ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ Gaze-based Multimodal Shareable Tangible Augmented and mixed reality Wearable Robots Brain-computer Smart (human-AI) … Haptic September 21, 2026 Beat Signer - Department of Computer Science - bsigner@vub.be 26
27. Command-based Interfaces ▪ Typing commands such as ls or rm in command line ▪ Combination of keys such as Ctrl + c and Ctrl + v ▪ Superseded by GUIs ▪ Still used by experts ▪ batch processing ▪ Alternative to GUIs for visually impaired users ▪ e.g. command-line interface for Second Life September 21, 2026 ▪ Syntax (e.g. how to combine commands) ▪ Which names can be remembered best ▪ Consistency in labeling and naming of commands Beat Signer - Department of Computer Science - bsigner@vub.be 27
28. WIMP and GUI ▪ Originated from Xerox Star interface ▪ Windows ▪ scroll, stretch, overlap, open, close, move ▪ Icons ▪ Original 1984 Mac OS desktop representing applications, objects or commands ▪ Menus ▪ scrollable list of options ▪ Pointer / Pointing Device ▪ mouse controlling the cursor September 21, 2026 Comodore 64, Magic Desk, 1983 Beat Signer - Department of Computer Science - bsigner@vub.be 28
29. Virtual Reality Interfaces ▪ Computer-generated graphical simulations ▪ illusion of participation in a virtual environment (VE) ▪ Use of CAVEs (Cave Automatic Virtual Environment) or headsets ▪ New ways of navigating in 3D space ▪ How to prevent users from experiencing nausea ▪ Identify most effective ways for ▪ First-person view or thirdperson perspective September 21, 2026 Meta Quest 3 headset navigation ▪ Best ways to interact with information Beat Signer - Department of Computer Science - bsigner@vub.be 29
30. Web Interfaces ▪ Website should be aesthetically pleasing ▪ usable ▪ easy to maintain ▪ ▪ Users do often not read all the content on a page before following a link ▪ Emphasis on content and the ▪ Bring the desktop to the use of links for navigation browser ▪ Where am I? What’s here? HTML5 and JavaScript ▪ AJAX ▪ … ▪ Web Content Accessibility ▪ September 21, 2026 Where can I go? Guidelines (WCAG) Beat Signer - Department of Computer Science - bsigner@vub.be 30
31. Mobile Interfaces ▪ Main difference in size and portability ▪ ready at hand 24/7 ▪ Real-time access to contextual information scanning product barcodes while shopping ▪ scanning QR codes ▪ ▪ Small screen and limited control space ▪ Location-based services ▪ Various guidelines on how to and recommendations design mobile interfaces ▪ Privacy issues ▪ September 21, 2026 location sharing applications Beat Signer - Department of Computer Science - bsigner@vub.be 31
32. Speech (Voice) Interfaces ▪ Various applications flight times or buying a ticket ▪ replace touchtone navigation ▪ real-time translators ▪ ▪ Supports visually impaired users ▪ Voice recognition and text- ▪ Natural interfaces vs. voiceto-speech technology based menu navigation specific grammars to improve ▪ Type of voice actor recognition rate ▪ Immediate confirmation of ▪ barge-in requests ▪ September 21, 2026 Beat Signer - Department of Computer Science - bsigner@vub.be 32
33. Pen Interfaces ▪ Based on writing skills edfestComponents developed from childhood ▪ digitalisation of handwriting ▪ Stylus on screen vs. digital pen and paper ▪ Quick and easy way to annotate documents ▪ Intuitive interfaces to integrate physical paper with digital information and services September 21, 2026 EdFest, Global Information Systems Group, ETH Zurich ▪ Switching from writing, annotating or sketching to the execution of commands ▪ context-sensitive menus ▪ Feedback for digital pen and paper interfaces Beat Signer - Department of Computer Science - bsigner@vub.be 33
34. Gesture-based Interfaces ▪ Tracking of people’s body, arm and hand gestures Nintendo Wiimote ▪ Microsoft Kinect ▪ … ▪ ▪ Mid-air gestures also used for controlling home appliances ▪ Sign language interpreters Microsoft Kinect ▪ Detection (start /end) and recognition of mid-air gestures ▪ continous input stream ▪ Gestures vs. unconscious gesticulation ▪ Control device vs. hands-free September 21, 2026 Beat Signer - Department of Computer Science - bsigner@vub.be 34
35. Gaze-based Interfaces ▪ Control computer by simply looking at it ▪ Very fast and accurate hands-free input ▪ Good for pointing but less suited for smooth drawing ▪ Useful for evaluations in HCI ▪ Increasing use in Virtual and Mixed Reality September 21, 2026 Canon EOS R3 Eye Control AF ▪ Often needs some initial calibration ▪ How to distinguish deliberate gazing from accidental glancing? Beat Signer - Department of Computer Science - bsigner@vub.be 35
36. Multimodal Interfaces ▪ Enriched user experience by using multiple input and output modalities speech and gesture ▪ eye-gaze and gesture ▪ pen input and speech ▪ … ▪ ▪ Multiple modalities might SpeeG2, WISE lab, VUB ▪ Recognition and calibration of different aspects of a user’s behaviour is more difficult be used simultaneously or alternately ▪ Identify gains of combining different input and output modalities September 21, 2026 Beat Signer - Department of Computer Science - bsigner@vub.be 36
37. Tangible Interfaces ▪ Physical objects are coupled with digital representations ▪ Sensing of physical objects and feedback in digital or physical space ▪ Interplay of different devices and objects ▪ no enforced sequencing and no modal interaction ▪ Affordances of interface objects guide the user September 21, 2026 ArtVis, WISE lab, VUB ▪ Coupling between physical action and effect ▪ where to provide digital feedback ▪ What kind of physical artefacts should be used ▪ bricks, cubes, sticky notes, … Beat Signer - Department of Computer Science - bsigner@vub.be 37
38. Augmented and Mixed Reality ▪ Augmentation of the physical environment with digital information and services ▪ Information can be visualised (overlaid) in different ways head-mounted displays (HMDs) ▪ handheld displays ▪ fixed installations ▪ September 21, 2026 Microsoft HoloLens ▪ Form of the digital augmentation and when and where it should be applied ▪ Very different designs ▪ playful learning experience ▪ medical application Beat Signer - Department of Computer Science - bsigner@vub.be 38
39. Wearable Interfaces ▪ Various new materials flexible display technologies ▪ e-textiles ▪ ▪ Glasses, jewellery, shoes or jackets as user interfaces Smart contact lens ▪ Wearable technology for remote awareness ▪ Hug Shirt by CuteCircuit for mobile phone calls ▪ Wearable interfaces have to be comfortable ▪ Hygiene is an issue ▪ washing of e-textiles ▪ Social acceptance and privacy September 21, 2026 Beat Signer - Department of Computer Science - bsigner@vub.be 39
40. Robots ▪ Originally used in manufacturing assembly lines and to investigate hazardous locations ▪ More recently domestic robots for cleaning and gardening ▪ e.g. Roomba iRobot ▪ Pet robots and human-like robots used in therapies Emergent Communication, AI lab, VUB ▪ Ethical concerns ▪ robots with human- or animal-like behaviour ▪ Communication with robots ▪ human-”human” vs. human- machine interaction September 21, 2026 Beat Signer - Department of Computer Science - bsigner@vub.be 40
41. Smart/Intelligent Interfaces A screenshot of a computer ▪ Smart devices commu- AI-generated content may be incorrect. nicating with users and other devices often learn the context and user behaviour (AI) ▪ implicit interactions do not have to be triggered by user ▪ ▪ Smart environments such as smart homes or offices eSPACE authoring tool, WISE lab, VUB ▪ Minimise mismatch between user expectations and actions triggered by the system ▪ Intelligibility offers users insights about the system behaviour September 21, 2026 Beat Signer - Department of Computer Science - bsigner@vub.be 41
42. Which Interface Should We Use? ▪ In the last few years there is a significant increase in the number of user interface types ▪ How to decide which interface is preferable for a given task or activity? speech vs. command-based interface ▪ multimodal vs. monomodal interface ▪ wearable vs. mobile interface ▪ virtual reality vs. augmented reality ▪ … ▪ ▪ Many of these questions are currently being researched ▪ this course will provide you some more insights about the design process and human-computer interaction-related issues September 21, 2026 Beat Signer - Department of Computer Science - bsigner@vub.be 42
43. Exercise 1 ▪ Discussion of existing human-computer interfaces and interactions September 21, 2026 Beat Signer - Department of Computer Science - bsigner@vub.be 43
44. Further Reading ▪ Parts of this lecture are based on the book Interaction Design: Beyond Human-Computer Interaction ▪ chapter 7 - Interface Types September 21, 2026 Beat Signer - Department of Computer Science - bsigner@vub.be 44
45. References ▪ Interaction Design: Beyond Human-Computer Interaction, Yvonne Rogers, Helen Sharp and Jenny Preece, Wiley (6th edition), April 2023 ISBN-13: 978-1119901099 ▪ Designing with the Mind in Mind: Simple Guide to Understanding User Interface Design Guidelines, Jeff Johnson, Morgan Kaufmann (3rd edition), November 2020, ISBN-13: 978-0192864550 ▪ Introduction to Human-Computer Interaction, Kasper Hornbaek, Per Ola Kristensson and Antti Oulasvirta, Oxford University Press, September 2025, ISBN-13: 978-0130461094 September 21, 2026 Beat Signer - Department of Computer Science - bsigner@vub.be 45
46. References ... ▪ Research Methods in Human-Computer Interaction, Jonathan Lazar, Jinjuan Heidi Feng and Harry Hochheiser, Morgan Kaufmann (2nd edition), May 2019, ISBN-13: 978-0128053904 ▪ Designing for Interaction: Creating Innovative Applications and Devices, Dan Saffer, New Riders (2nd edition), August 2009 ISBN-13: 978-0321643391 ▪ The Design of Everyday Things, Don Norman, Basic Books (revised and expanded edition), November 2013, ISBN-13: 978-0465050659 September 21, 2026 Beat Signer - Department of Computer Science - bsigner@vub.be 46
47. References ... ▪ B. Signer, Pen-based Interaction, Handbook of Human Computer Interaction, Major Reference Work, Springer Nature, 2025 ▪ https://beatsigner.com/publications/pen-based-interaction.pdf ▪ M.C. Norrie, B. Signer, M. Grossniklaus, R. Belotti, C. Decurtins and N. Weibel, Context-Aware Platform for Mobile Data Management, Wireless Networks (WINET), 13(6), Springer, December 2007 ▪ https://beatsigner.com/publications/norrie_WINET2007.pdf September 21, 2026 Beat Signer - Department of Computer Science - bsigner@vub.be 47
48. References ... ▪ L. Hoste and B. Signer, SpeeG2: A Speech- and Gesture-based Interface for Efficient Controller-free Text Entry, Proceedings of the 15th International Conference on Multimodal Interaction (ICMI 2013), Sydney, Australia, December 2013 ▪ https://beatsigner.com/publications/hoste_ICMI2013.pdf ▪ B. Dumas, B. Moerman, S. Trullemans and B. Signer, ArtVis: Combining Advanced Visualisation and Tangible Interaction for the Exploration, Analysis and Browsing of Digital Artwork Collections, Proceedings of AVI 2014, Como, Italy, May 2014 ▪ https://beatsigner.com/publications/dumas_AVI2014.pdf September 21, 2026 Beat Signer - Department of Computer Science - bsigner@vub.be 48
49. References ... ▪ A. Sanctorum and B. Signer, eSPACE: Leveraging Theoretical Foundations for the End-User Development of Cross-Device and IoT Applications, ACM Transactions on Computer-Human Interaction (TOCHI), February 2025 ▪ https://beatsigner.com/publications/sanctorum_TOCHI2025.pdf ▪ B. Signer, Towards Cross-Media Information Spaces and Architectures, Proceedings of the 13th International Conference on Research Challenges in Information Science (RCIS 2019), Brussels, Belgium, May 2019 ▪ https://beatsigner.com/publications/signer_RCIS2019.pdf September 21, 2026 Beat Signer - Department of Computer Science - bsigner@vub.be 49
50. References ... ▪ Sketchpad Demo ▪ https://www.youtube.com/watch?v=6orsmFndx_o ▪ Videos of the NLS demo ▪ https://www.youtube.com/watch?v=yJDv-zdhzMY September 21, 2026 Beat Signer - Department of Computer Science - bsigner@vub.be 50
51. Next Lecture HCI and Interaction Design 2 December 2005