this paper investigates the multiplicative spread spectrum watermarking method for the image. the information bit is spreaded into middle-frequency discrete cosine transform (dct) coefficients of each block of an image using a generated pseudo-random sequence. unlike the conventional signal modeling, we suppose that both signal and noise are distributed with laplacian distribution, because the ...

In this letter, we propose an efficient on-the-fly algorithm for maximum-likelihood decoding of Raptor codes used over the binary erasure channel. It is shown that our proposed decoding algorithm can reduce the actual elapsed decoding time by more than two-thirds with respect to an optimized conventional maximum-likelihood decoding. key words: raptor codes, on-the-fly decoding, maximum-likeliho...