CSC 310
Information Theory
TA: Darius Braziunas (darius@cs) Assignment #3 grading scheme The
assignment was graded by both Cosmin and Darius.
Question 1 (Cosmin)
 * 18 marks (6 for 1A, 6 for 1B, 6 for 1C) are awarded as follows: 1A (i), 1B (i), 1C (i) 3 marks for a good approximation of c(T) 1A (ii), 1B (ii), 1C (ii) 1 marks for a good approximation of R 1A (iii), 1B (iii), 1C (iii) 2 marks for the correct results * 2 marks (1 for 1A, 1 for 1B) are awarded for a proper argumentation (including induction, or an inductionlike explanation) supporting the relation between T and c(T). Specifically, it's not enough to observe (in 1A) that the first codewords have the lengths 1, 2, 3, 4 ..., you must also explain why the nth codeword has the length n (which is actually quite simple, but must not be overlooked). Ditto for 1B. Total: 20 marks Question 2 (Darius)  Q2: A. 2 B. 3 (2 for the matrix and one for the entropy) C. 3 (2 for the matrix and one for the entropy) D. 3 (2 for the matrix and one for the entropy) E. 3 (2 for the matrix and one for the entropy) F. 3 G. 3 (2 for p0 = p1 = .5, and 1 for .3651) Total: 20 marks Question 3 (Darius)  Q3: A. 6 (2 for each full code) B. 4 (one for each rate, and one for the comparison to H[7,4]) C. 6 (2 for each requested disttibution) D. 2 (1 for saying that one bit errors are corrected; 1 for saying that the [4,1] code can also detect 2 bit errors) Here, I also counted as correct the answers were the number of errors detected was given as d1, where d is the minimum distance (as long as the answers were consistent). E. 2 Total: 20 marks Question 4 (Cosmin)  * Notes: * If you CONSISTENTLY used the squared error for distortion (which gave you different final results), you will still receive proper credit. * If you started the calculations well, but you made mistakes on the way and obtained different (but credible) results, you will still receive proper credit. * 3 marks awarded for 4A. * 6 marks awarded for 4B. * 2 marks for each case (alpha = 0,30,60). * [The LloydMax algorithm is NOT applicable] * 6 marks awarded for 4C. * 2 marks for each case (alpha = 0,30,60). * [The LloydMax algorithm IS applicable] * If you didn't iterate using LloydMax, but you used an acceptable quantization method (such as equalweight quantization), and you did observe that LloydMax iterations can further improve the distortion, you will not be penalized. * If you didn't even mention LloydMax, you will be penalized by 1 point. * 5 marks awarded for 4D. * 1 mark for alpha = 60. * 3 marks for alpha = 0,30. * 1 mark for comparing the distortion values to the results obtained in 4B. Total: 20 marks Updated: April 16, 2003
