Spotlights

Human–Computer Interaction

User interfaces of computing systems inspired me from the very first; since I played with my Game Boy as a child: I was fascinated by the elegant solutions developed by clever minds to let humans communicate with machines; using convenient input devices (hardware) or graphical user interfaces (software).

My guiding principles:

1. Clear access for people who prefer other senses than vision
   • Accessibility (from June 28, 2025: EU Directive: European Accessibility Act)
2. Always treat input data carefully
   • clearly written business logic in program code
3. Do not overcrowd the screen
   • modest distribution of contents over several pages
   • sufficient size of control elements
   • Courage to make smart sacrifices (“sunk cost”)
4. The program must react like the user knows it
   • analyze popular apps
   • Cognitive Dimensions of interactive devices
5. Shortest possible reaction delay
   • users' time is precious
6. Clearly communicate longer reaction delays
   • loading indicators and no surprising jumps
7. Good preparation is half the work
   • Focus Groups for a first approach
   • Personas
   • Card Sorting
   • Storyboard→Wireframe→Simulation
   • test user observation already with very first prototypes
   • Ask experts among the future users:
     Heuristic Evaluation, Cognitive Walkthrough, Thinking Aloud

Teamwork

The benefits of working together are obvious in all areas of life, and range from getting things done faster, over sharing skills, to motivating each other. Mountaineering in a roped party as a collaborative project demonstrates within a single day that teamwork pays off.

Data Safety and Security

Error-free backends and robust network communication are of special interest to me: I feel good if data are transmitted and stored safely. That means:

1. Inevitable data corruption must be detected automatically.
   Possible reasons for data corruption are: transmission errors, hardware defects, software errors
2. Corrupted or lost data must be restorable.
3. Data changes must be traceable and reversible on demand.
4. Data should be preserved and readable even after decades if necessary.
5. My programs are optimized for data consistency.

Programming Languages

My considerable interest in programming languages stems from my interest in technology on the one hand and human languages on the other. During my professional career I have worked in-depth with more than 10 programming languages, which allowed me to develop a toolbox of robust solutions. All languages have their pros and cons, but even if you are forced to work with one of the most complicated languages, general concepts may help to write robust code.