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Steganographic techniques with varying degrees of embedding capacity, perceptual transparency, and security are presented. These techniques have been developed to protect privileged or confidential information restricted to public access and to replace cryptography methods. In this study, three embedding algorithms, namely, least significant bit insertion, bit-plane complexity segmentation, and enhanced version of pixel value difference (EPVD) were implemented and analyzed in terms of the main steganography issues (payload, invisibility, and security) using a different proper performance metrics. This study was motivated by the minimal research focus accorded to hiding data in compression domain for the class of video-based embedding methods. Therefore, analyzing steganographic algorithms is generally based on hiding information in the quantized AC-Coefficients of the frames during the MPEG-2 compression process. Simulation results reveal that EPVD provides better embedded payload and acceptable visual quality, but lower PSNR value.

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The aim of this paper is to determine the Fekete-Szegö inequalities for a normalized analytic function defined on the open unit disk lies in a region starlike with respect to 1 and it is symmetric with respect to the real axis by using the operator given recently by the authors. As a special case of this result, Fekete-Szegö inequality for a class of functions defined by fractional derivatives is also obtained.

Ad hoc underwater acoustic networks represent a very challenging field in digital communications due to the extreme nature of the underwater acoustic channel and also the requirement to meet critical needs in order to establish long range propagation, decentralisation and reliability. As a fact the underwater acoustic communications speed is five times less than the magnitude of the radio waves, and this makes the underwater acoustic suffer from high propagation delay and minimum throughput. This paper discusses the influence of the backoff windows on the ad hoc on demand Destination Sequenced Distance Vector (DSDV) protocol. Underwater Acoustic Media Access Control (UAMAC) is implemented in a NS2 simulator to adopt the Multiple Access Collision Avoidance and Acknowledgment (MACAW) scheme. The simulation results for the developed system are presented.