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High dynamic range (HDR) images contain more details of dark and bright regions, which cannot be captured by the standard cameras. Raw HDR data is represented with floating-point precision, and the commonly used lossless/near-lossless HDR image encoding formats produce files that require large storage and are not suitable for transmission. Methods have been proposed for lossy encoding using single- and dual-layer structures, but the codecs are generally more complex and often require additional metadata for decoding. We propose a dual-layer codec in which companding, which is a closed-form transformation and hence can be reversed without any additional data, is used to generate the first layer. The residual data stored in the second layer is quantized linearly and do not need metadata either for decoding. The proposed codec is computationally light, has higher accuracy, and produces smaller size files compared to the existing codecs. This has been validated through an extensive evaluation using different metrics, and the results are reported in the paper. [ABSTRACT FROM AUTHOR]

In this paper, single and multiple S-box encryption issues are discussed and a new algorithm is then proposed to solve those issues. As the single S-box encryption completely fails to encrypt the plain image because a single S-box replaces the pixels of the same region with a unique symbol. To break this type of correlation in the image, chaos has been extensively used. The multiple S-boxes techniques are becoming more popular over the last decade to overcome the drawbacks of single S-box encryption. However, replacing single S-box with multiple S-boxes is somehow good for the encryption of those images which contain more number gray levels i.e 256 gray levels, but it cannot properly conceal the pixels of an image having less number of gray levels i.e binary or plain white images which contain only one gray level. To solve these issues, a dynamic substitution based encryption algorithm (DSA) is proposed, which is specially designed for the highly correlated images. Security analysis and evaluation show that the proposed algorithm can accomplish to conceal the highly correlated data. [ABSTRACT FROM AUTHOR]

Most of recent research in multicore processor architectures has been shifted towards reconfigurable architectures due to increasing complexity of computing systems. These systems provide better application-specific energy and throughput balance with their reconfigurable behavior. They perform automatic run time resource allocation for an application as per its needs. But in terms of performance, current methodologies produce some unpredictable results because of the actual variety of the workloads. Therefore, we need optimization of the system resources usage by employing some optimization algorithms. Early research in the field of reconfigurable architecture using optimization algorithms has produced efficient results for energy consumption with the reconfiguration of cache sizes and associativity, number of cores and operating frequency. In this research, we propose particle swarm optimization (PSO) based algorithm, Integer PSO (IPSO) for design space exploration of reconfigurable computer architectures to have better energy and throughput balance. The results obtained by IPSO are evaluated by using various SPLASH-2 benchmark applications. Evaluation shows notable reduction in energy consumption without major effect on throughput. Simulation results also support the use of IPSO in design space exploration of multicore reconfigurable processor architectures. [ABSTRACT FROM AUTHOR]

The fields of applied sciences and engineering require Pseudorandom Number Generators which exhibit useful statistical properties. In this paper, a novel algorithm for generating pseudorandom numbers has been proposed. This new algorithm is based on Duffing map. The aim of this paper is to generate pseudorandom bit streams based on chaotic map. The main objective is to find its potential to be used in applied sciences and engineering applications. To use this algorithm effectively in practical applications, the strength of this algorithm has been tested using various statistical tests like initial seed value, key sensitivity test, CPU performance test and pseudorandom orbit. The proposed pseudorandom number generator is further analyzed and evaluated with NIST statistical test suite. The results obtained from these experimental and statistical tests demonstrate and prove that the new generator has the potential to be applied successfully in mathematical sciences, applied physics, computer science and electrical engineering etc. [ABSTRACT FROM AUTHOR]

Chaos has been applied extensively in secure communication over the last decade, but most of the chaotic security protocols defined, are cryptographically weak or slow to compute. Also, study of chaotic phenomena as application in security area is not discussed in detail. In this paper, we have intensely studied chaos, their influence in secure communications and proposed a steganography technique in spatial domain for digital images based upon chaotic maps. By applying chaos effectively in secure communication, the strength of the overall anticipated algorithm has been increased to a significant level. In addition, few security statistical analyses such as correlation, entropy, energy, contrast, homogeneity, peak signal to noise ratio, and mean square error have also been carried out and shown that it can survive against various differential attacks such as the known message attack, known cover attack, known stego attack, and stego only attack. [ABSTRACT FROM AUTHOR]

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