node Quiz

    Imagine a full binary tree in which the probability of getting from any parent node to one of its child nodes is 50%. Associate labels of '0' and '1' to the paths to the child nodes of each parent node. Then the probability of getting from the root to a leaf node is a negative power of 2, and the length of the path (from the root to that leaf node) is the negated base-2 logarithm of that probability. Now imagine a random bit stream in which each bit has an equal chance of being either 0 or 1. Think of the full binary tree as describing a Huffman encoding for a script whose characters are located at the leaf nodes of the said full binary tree. Each character decodes a string of bits whose length is the length of the path from the root node to the leaf node corresponding to that character. Now use "Huffman decoding" to convert the bit stream to a character stream (of the given script). The average compression ratio between the bit stream and the character stream can be seen to be equal to the information entropy of the character stream.

Initially, we set the following 2 criteria to determine the concentration of a protein: 1) the retention times of peaks in multichromatograms of transitions should be the same between endogenous peptide, thereby confirming that the peptide originated from the target protein; and 2) the transition should have an average peak height for endogenous peptide above 1000 cps in the massive lymph node metastasis group.