Showing papers by "Shu-Chuan Chu published in 2005"

A Parallel Particle Swarm Optimization Algorithm with Communication Strategies

Abstract: Particle swarm optimization (PSO) is an alternative population-based evolutionary computation technique. It has been shown to be capable of optimizing hard mathematical problems in continuous or binary space. We present here a parallel version of the particle swarm optimization (PPSO) algorithm together with three communication strategies which can be used according to the independence of the data. The first strategy is designed for solution parameters that are independent or are only loosely correlated, such as the Rosenbrock and Rastrigrin functions. The second communication strategy can be applied to parameters that are more strongly correlated such as the Griewank function. In cases where the properties of the parameters are unknown, a third hybrid communication strategy can be used. Experimental results demonstrate the usefulness of the proposed PPSO algorithm.

Equal-average Equal-variance Equal-norm Nearest Neighbor Codeword Search Algorithm Based on Ordered Hadamard Transform

Abstract: This paper presents a fast codeword search algorithm that performs the equalaverage equal-variance equal-norm nearest neighbor search (EEENNS) in the ordered Hadamard transform (OHT) domain. By reordering the rows of Hadamard transform matrix, we can obtain the OHT with better energy packing efficiency, which is very important to the partial distance search (PDS) stage. Four elimination criteria based on three characteristic values, the first element, variance, and norm of the transformed vector, are introduced to reject a large number of unlikely codewords. Experimental results show that the proposed OHTEEENNS algorithm outperforms most of existing algorithms in the case of high dimension, especially for high-detail images.

Multiple description watermarking for lossy network

Abstract: The paper proposes an innovative watermarking scheme based on vector quantization (VQ); it is suitable for media transmission over noisy channels with multiple description coding (MDC). Digital watermarking is one of the applicable tools that can be used to protect digital contents from illegal copying and distribution. In addition to conventional schemes that apply attacks on watermarked media, we focus our application on transmitting over noisy channels to consider both the error-resilient transmission of watermarked media, and the robustness of the watermarking algorithm. By modifying the multiple description vector quantization (MDVQ) algorithm for watermark embedding and extraction, simulation results not only demonstrate the effective transmission of a watermarked image, but reveal the robustness of the extracted watermark.

A new steganography scheme in the domain of side-match vector quantization

Abstract: This article reports a pioneer work on a steganography scheme in the domain of side-match vector quantization. The challenge associated with dynamic state code books had been resolved by two possible alternatives, namely code book partition by code words' mean and code book partition by pseudo random sequence. Experiment results reveal that imperceptibility required for secret communication can be ensured with the proposed approaches.