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 induction-like 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 n-th 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 d-1, 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 Lloyd-Max algorithm is NOT applicable] * 6 marks awarded for 4C.   * 2 marks for each case (alpha = 0,30,60).   * [The Lloyd-Max algorithm IS applicable]   * If you didn't iterate using Lloyd-Max, but you used an acceptable     quantization method (such as equal-weight quantization), and you     did observe that Lloyd-Max iterations can further improve the     distortion, you will not be penalized.   * If you didn't even mention Lloyd-Max, 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