Ratnakirti Roy

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This paper reviews the main challenges posed by the underwater environment for the development of efficient under water sensor networking solutions and proposes a novel medium access control (MAC) protocol with power control to increase efficiency and save on energy. Underwater channel is characterized by high propagation delay, limited bandwidth capacity,(More)
Steganography is the science of hiding crucial information in someinnocuous objects such that the mere existence of the hidden information is unidentifiable in human sight. Various unique methodologies have been implemented over time to hide information using steganography. In most of the methodologies the exact secret information is hidden inside the cover(More)
In this paper, recent advances in parallel software development for solving neutron transport problems are presented. The method of characteristics is based on the resolution of the differential transport equation following the tracking lines in order to collect the local angular flux components. Due to the excessive number of tracks in the demanding(More)
Steganography is the art of hiding information secretly inside a multimedia signal in such a way that its very existence is concealed. In this paper a new image steganography technique has been proposed which is based on the pixel value differencing and the pixel value sum of two consecutive pixels of a cover image. The proposed algorithm hides the secret(More)
Steganography is the art and science of concealing information inside apparently innocuous covers like images, audio and video such that the very existence of the hidden message remains imperceptible to an adversary. Image steganography has numerous implementations developed over time. It is evident that certain areas in the image are more efficient for(More)
This paper discusses the steganographic data hiding using the wavelet approach and the optimisation technique. The Discrete Wavelet Transform Using Haar Wavelet gives the excellent peak signal to noise ratio (PSNR) and less computation time. The particle swarm optimisation algorithm (PSO) is also used to hide the data so that the PSNR is improved. The(More)
We present a new computational methodology, based on 3D characteristics method, dedicated to solve very large 3D problems without spatial homogenization. In order to eliminate the input/output problems occurring when solving these large problems, we set up a new computing scheme that requires more CPU resources than the usual one, based on sweeps over large(More)
Image Realization Steganography aims in devising techniques that realize a secret message from a cover image using a suitable cover-to-secret mapping with low embedding rates. This paper presents an Image Realization Steganography technique which maps a secret image as a Longest Common Subsequence of a given cover image. The cover image being a string of(More)
Steganography is a process to hide secret data into a cover media in an imperceptible manner. In the spatial domain of image steganography, the most common technique is Least Significant Bit Replacement (LSBR). However, LSBR is extremely sensitive to compression attacks involving truncation of LSBs. As a possible solution to the drawback of the traditional(More)
Steganography techniques find importance in military applications because of their ability to communicate covertly. It is evident for any image steganography technique that if the payload can be represented in a smaller dimension than its original form, then the actual embedding requirement can be lessened thereby improving the statistical imperceptibility(More)