# Questions tagged [compression]

Use this tag for questions about encoding information using fewer bits than the original representation.

80 questions
Filter by
Sorted by
Tagged with
29 views

### Can we modify the Lempel-Ziv 77 algoritm utilizing periodic functions in mathematical analysis?

The Lempel-Ziv 77 is a classical data compression scheme which was popular in early data compression algorithms. For example in deflate and GIF. One useful and curious special property of LZ77 is its ...
23 views

### Why Lempel-Ziv77 - “sliding window” algorithm uses a fixed length code for the buffer u?

I am a final year ECE student from Greece, studying about Information Theory a question came up. In the definition/description of LZ77 (Lempel-Ziv's algorithm), following is noted: "If n > 1, ...
14 views

### TOP p most informative elements in a mutually recursive multisets?

Let say we have two groups of multi-sets /repeatable elements are allowed/ i.e. ...
77 views

44 views

28 views

### Proof average codeword length of a prefix code $C$ is the sum of probability of all leaf vertices that are descendant

Let $I$ represent the set of all interior vertices in a binary tree. Define the probability of vertex $v \in I$ is $P(v)$, which is the sum of the probabilities of all leaf vertices that are ...
44 views

### How to increase the compression of an RGB image from a typical smartphone camera from 2:1 to perhaps 3:1?

I have been experimenting with a simple (fixed resolution) image file compressor that I designed and wrote from "scratch", for fun, and to keep my programming skills "sharp". So ...
17 views

### Is Prediction the same as Compression?

Just came across this transcript that states: The principle is that prediction is the same thing as compression. And what that means is that whenever you have a prediction algorithm, you can also get ...
51 views

### Extending Given Digits to make Perfect Powers

I read this article titled Extending Given Digits to make Primes or Perfect Powers by Sury B, which appeared in the Resonance periodical (October 2010, Indian Statistical Institute, Bangalore). In ...
18 views

### Let $W$ be random matrix and $b$ be vector. Let $x$ be secret vector; let $(y(x))_j = \max(W_j^Tx+b,0)$. Find $x' \in B(x;r)$ s.t $y(x')=y(x)$ whp

Let $1 \le n \le p$ be large positive integers. $W$ be a random $n \times p$ matrix with entries drawn iid from $\mathcal N(0,1/p)$ and let $b$ be an $n$-dimensional random vector with coordinates ...
167 views