|2.2 Text Compression Enrichment
Real World: Zip Compression
- Experiment with zip using text files with different contents. Are the results for small files as good as for large files? (On Macs, in the Finder choose “get info” for a file to see the actual number of bytes in the file, since the Finder display will show 4KB for any file that’s less than that.)
- Warning: results may vary. Zip works really well for text, but it might not compress other files very well because they are already compressed or don’t have the same kinds of embedded patterns that text documents do.
Challenge: Research the LZW algorithm
- .zip compression is based on the LZW Compression Scheme
- While the idea behind the text compression tool is similar to LZW (zip) algorithm, tracing the path of compression and decompression is somewhat challenging. Learning more about LZW and what happens in the course of this algorithm would be an excellent extension project for some individuals.
|Explore PT Requirements
Digital Artifact and Written Response Submitted in Google Drive Due Mon 10/9
|2.3 Encoding B&W Images Enrichment
- Check out the “Color by Numbers” from CS Unplugged (csunplugged.org) which uses a different clever encoding scheme for B&W images.
- Have students research raster graphics in anticipation of the subsequent lesson.
- Attempting to communicate with possible intelligent life beyond our solar system has been a dream for humans and the goal of scientists for many years. Questions about messages to send, as well as how to send messages deep into space to unknown recipients have been debated. In 1974, scientists sent the Arecibo message to the star cluster M13 some 25,000 light years away. Read about the message they sent using 1,679 binary digits (https://en.m.wikipedia.org/wiki/Arecibo_message).
- How would you change the content of the message? What would you delete and add? Why would your change be significant in a communication to other intelligent beings?
- Sketch the segment of the design you would alter. Remember, you must retain the original number of bits.
- List the details in this article that you understand more deeply because of what you have learned in this class up to this point.