Ajay Kumar Bisoi

Bio: Ajay Kumar Bisoi is an academic researcher from KIIT University. The author has contributed to research in topics: Digital watermarking & Watermark. The author has an hindex of 9, co-authored 18 publications receiving 281 citations. Previous affiliations of Ajay Kumar Bisoi include International Centre for Theoretical Physics & Utkal University.

Comparative study of image encryption using 2D chaotic map

Abstract: Securing digital image during transmission is very much important in the current era. For this purpose, cryptographic techniques as well as chaotic maps can be applicable. In this paper, we have given a detailed study of the image encryption using different 2D chaotic maps such as Arnold 2D cat map, Baker map, Henon map, Cross chaos map and 2D logistic map. The security analysis of these techniques has been done by the help of NPCR (Number of Pixels Change Rate) and UACI (Unified Average Changing Intensity) values. The experimental results of NPCR and UACI show the effectiveness of the encryption processes of different techniques.

Non blind digital watermarking technique using DCT and Cross chaos map

Abstract: Digital watermarking is the process of embedding secret information into a digital signal which may be used to verify its authenticity or the identity of its owners. In this paper, a non-blind digital image watermarking algorithm based on Discrete cosine transform, Cross chaotic map and Arnold transform has been described. Initially, Arnold's transformation is applied on the watermark signal. Then, Cross chaos sequence is applied on this encrypted watermark to encrypt further. Discrete cosine transformation is applied to the cover image to transform the signal from the spatial domain to the frequency domain, where the watermark signal is embedded. It is a kind of non-blind scheme as the extraction needs the original image. Peak signal to noise ratio (PSNR) is used to evaluate the algorithm. The quality of the extracted watermark is evaluated using term Normalized cross-correlation (NC). From the results, it may be concluded that our algorithm is resistant enough against the common attacks.

Pseudoscalar-versus-pseudovector interactions in photo- and electroproduction of charged mesons

Abstract: The possibilities of distinguishing between pseudoscalar (ps) and pseudovector (pv) couplings by an analysis of experimental data on photoproduction and electroproduction processes are discussed. It is argued that the charged-${K}^{+}$ electroproduction experimental results may be more reliable for the purpose. It is seen that "Born terms" can explain the qualitative features of some existing data on photo- and electroproduction of $\ensuremath{\pi}$ and $K$ mesons.

[서평]「Applied Cryptography」

Abstract: The objective of this paper is to give a comprehensive introduction to applied cryptography with an engineer or computer scientist in mind. The emphasis is on the knowledge needed to create practical systems which supports integrity, confidentiality, or authenticity. Topics covered includes an introduction to the concepts in cryptography, attacks against cryptographic systems, key use and handling, random bit generation, encryption modes, and message authentication codes. Recommendations on algorithms and further reading is given in the end of the paper. This paper should make the reader able to build, understand and evaluate system descriptions and designs based on the cryptographic components described in the paper.

Global patterns of tropical forest fragmentation

Abstract: Remote sensing enables the quantification of tropical deforestation with high spatial resolution. This in-depth mapping has led to substantial advances in the analysis of continent-wide fragmentation of tropical forests. Here we identified approximately 130 million forest fragments in three continents that show surprisingly similar power-law size and perimeter distributions as well as fractal dimensions. Power-law distributions have been observed in many natural phenomena such as wildfires, landslides and earthquakes. The principles of percolation theory provide one explanation for the observed patterns, and suggest that forest fragmentation is close to the critical point of percolation; simulation modelling also supports this hypothesis. The observed patterns emerge not only from random deforestation, which can be described by percolation theory, but also from a wide range of deforestation and forest-recovery regimes. Our models predict that additional forest loss will result in a large increase in the total number of forest fragments-at maximum by a factor of 33 over 50 years-as well as a decrease in their size, and that these consequences could be partly mitigated by reforestation and forest protection.

Secure and robust digital image watermarking scheme using logistic and RSA encryption

Abstract: In the era of big data and networking, it is necessary to develop a secure and robust digital watermarking scheme with high computational efficiency to protect copyrights of digital works. However, most of the existing methods focus on robustness and embedding capacity, losing sight of security or requiring significant computational resources in the encryption process. This paper proposed a new digital image watermarking model based on scrambling algorithm Logistic and RSA asymmetric encryption algorithm to guarantee the security of the hidden data at the foundation of large embedding capacity, good robustness and high computational efficiency. The experiments involved applying the encryption algorithms of Logistic and RSA to the watermark image and performing the hybrid decomposition of Discrete wavelet transform (DWT) and Singular Value Decomposition (SVD) on the host image, and the watermark was embedded into the low-frequency sub-band of the host. The values of PSNR and NCC were measured to estimate the imperceptibility and robustness of the proposed watermarking scheme, and the CPU running time was recorded to measure the complexity of the proposed main algorithm in execution time. Experimental results showed the superiority of the proposed watermarking scheme.