Splay trees for data compression
Dennis Grinberg, Sivaramakrishnan Rajagopalan, Ramarathnam Venkatesan, Victor K. Wei · 1995
We present applications of splay trees to two topics in data compression. First is a variant of the move-to-front (mtf) data compression (of Bentley,Sleator Tarjan and Wei) algorithm, where we introduce secondary list(s). This seems to capture higher-order correlations. An implementation of this algorithm with Sleator-Tarjan splay trees runs in time (provably) proportional to the entropy of the input sequence. When tested on some telephony data, compression ratio and run time showed significant improvements over original mtf-algorithm, making it competitive or better than popular programs. For stationary ergodic sources, we analyse the compression and output distribution of the original mtf-algorithm, which suggests why the secondary list is appropriate to introduce. We also derive analytical upper bounds on the average codeword length in terms of stochastic parameters of the source. Secondly, we consider the compression (or coding) of source sequences where the codewords are required ...