CSC103 How Computers Work
Quiz4 & Assignment 4: Discussion & Best of the Week


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Quiz 4

The result (all quiz takings) are shown in the link on the syllabus page. The results were a bit weaker than usual, but more than compensated by the more heavily weighted assignment.

Assignment 4

The performance on this assignment was the best to date, with a class average of A (92.75).

This week let me highlight Claire Nadeau's clear and succinct responses to the first three questions:

  1. Each satellite can pinpoint the GPS receiver to a ‘sphere.’ Each sphere is slightly different, depending on the position of the satellite, and where all four spheres intersect is where the GPS unit is located. Any fewer number of satellites would drastically reduce accuracy. (http://en.wikipedia.org/wiki/Global_Positioning_System#Position_calculation_introduction)
  2. 2G phones were the first to be digitally encrypted, and were more efficient within the spectrum required for mobile phones because the digital voice data could be more compressed. They also introduced services like SMS texting. However, the weaker digital signal can’t always reach a tower, causing dropped calls. Under bad conditions, 2G phones will stop working more quickly. Also, the compression causes a loss of voice tone. 3G phones are even more efficient, meaning that they can offer more services, such as sending pictures and connecting to the internet. This was in response to demand for higher data rates. They are also more secure. However, 3G phones are expensive and tend to have a shorter battery life. (http://en.wikipedia.org/wiki/3G)( http://en.wikipedia.org/wiki/2G).
  3. Some programmers are worried that Microsoft will ‘force all free C# implementations underground’, meaning that any program written in the language while the language was free would be technically illegal to use.

Many of you had fun with Scratch, and I enjoyed running (and listening to!) your programs. Quite a few meowed. :-) Among the many I could highlight, here is Hu-Hsing Su's spiral, which gradually alters the shade of blue and simultaneously thickens the pen, and Marissa Cheng's and Valerie Vega's cute sprite:

HuiHsingMarissaValeria