We investigate the underlying mechanism of universal sequential, fixed distortion, lossy source coding algorithms, through the 'eyes' of a random code. We model the adaptive codebook as a 'mixed type' random code, whose codeword type distribution evolves with time while its dimension goes to infinity. The evolution law in our model has a structure of a tree; a type inherits its frequency in the code from its parent-types matching probabilities. We find that this mechanism naturally selects the 'good' codeword types for compressing the (unknown) source. As a consequence, the code becomes optimal for the source, and approaches the rate-distortion function as the time, and hence the dimension, go to infinity. Beyond its analytical interest, this model also provides guidelines for developing lossy string matching ('Lempel-Ziv-like') algorithms.
|Number of pages||3|
|State||Published - 1996|
|Event||Proceedings of the 1996 19th Convention of Electrical and Electronics Engineers in Israel - Jerusalem, Isr|
Duration: 5 Nov 1996 → 6 Nov 1996
|Conference||Proceedings of the 1996 19th Convention of Electrical and Electronics Engineers in Israel|
|Period||5/11/96 → 6/11/96|