Computational Thinking

Joel Gethin Lewis

Lecture 4: Compressing

What I'm going to talk about today:

1. Moving to four dimensions.
2. Artists working with space and time.
3. Text compression.
4. Spatial compression and Temporal compression.
5. The Fast Fourier Transform.
6. Bonus: three kinds of feedback: audio, visual and interactive.

1. Moving to four dimensions.

• Going from Cube to Hypercube.
• You can also go from the Sphere to the Hypersphere.
• You can also think of Time as the fourth dimension.
• You can use any variable as a new dimension, and measure distance between them using Pythagoras, as we saw in the previous article.
• Perfect Shapes in Higher Dimensions from Numberphile, which is a great channel to get lost in.

2. Artists working with space and time.

• Eadweard Muybridge, Sallie Gardner at a Gallop.
• Étienne-Jules Marey and the photographic gun.
• Marcel Duchamp, Nude descending a staircase.
• Umberto Boccioni, Unique Forms of Continuity in Space - see at the Tate Modern.
• James Turrell and skyspaces.
• Richard Long, A Line Made by Walking.

3. Text compression.

• Text compression is looking for patterns in text so that you can store those patterns, rather than the original content in order to reduce the file size of the text.
• Data compression is the general task of compressing any kind of information to save on bandwidth for transmission or file size for data storage, both of which used to be a lot more limited than today, to see how expensive and limited storage used to be, see this article.
• See this Computerphile video on Elegant LZ77 compression for more information.

4. Spatial compression and Temporal compression.

• JPEG is spatial compression for still images.
• MPEG is temporal compression for moving images and sound.
• Glitch and Glitch Art.
• See Rosa Menkman's amazing series of lectures on artefacts that result from accidents in both analogue and digital media (such as glitch, encoding and feedback).

5. The Fast Fourier transform.

• The Fast Fourier transform is a way of splitting up any waveform into a series of simpler waves.
• This can be very useful to find out how much bass, mid and treble any sound has and is used in music visualisers.
• See this great interactive website for an explanation and further links.
• See this interactive Better Explained article for a further, further explanation.

6. Bonus: three kinds of feedback: audio, visual and interactive.

• Feedback is when you feed the output of a signal into the input of it. It's a very powerful technique that can be used in a variety of fields:
• Audio feedback. Jimi Hendrix used this to great effect.
• Video feedback, the video equivalent.
• Nam June Paik, TV-Buddha. Media Art Net is a great resource.
• Douglas Trumbull, 2001 Star Gate Sequence.
• An Informal Catalogue of Slit-Scan Video Artworks and Research by Golan Levin. Slit Scan p5.js demonstration by Daniel Shiffman.
• Going around the corner piece by Bruce Nauman.
• Tell the story of making audio reactive visuals for Massive Attack in 2008.
• Finally, a great Twitter thread on the history of new media art from Greg J. Smith.

Thanks!

• Follow me on Insta! I follow back: @jgl
• Get in contact via: www.joelgethinlewis.com
• Website:
  https://jgl.github.io/ComputationalThinking2020
• Today's slides:
  https://jgl.github.io/ComputationalThinking2020/lecture4.html