A chaotic framework and its application in image encryption

A novel image encryption framework is proposed in this article. A new chaotic map and a pseudorandom bit generator are proposed. Apart from this, a novel image encryption system is designed based on the proposed map and the proposed pseudorandom bit generator. These three are the major contributions of this work that makes a complete cryptosystem. The proposed new chaotic map is proposed which will be known as the ‘RCM map’ and its chaotic property is studied based on Devaney’s theory. The proposed pseudorandom bit generator is tested using the NIST test suite. The proposed method is simple to implement and does not involve any highly complex operations. Moreover, the proposed method is completely lossless, and therefore cent percent of data can be recovered from the encrypted image. The decryption process is also simple to implement i.e. just reverse of the encryption procedure. A scrambling algorithm is also proposed to further enhance the security of the overall system. The simulation, detailed analysis, and comparative studies of the proposed overall image encryption framework will help to understand the strengths and weaknesses of it. The experimental results are very promising and show the prospects of chaos theory and its usage in the field of data security.

     

Recent developments in spectroscopy of quantum structures

Two spectroscopic techniques, modulated reflectance spectroscopy and surface photovoltage spectroscopy, are being used increasingly to probe the electronic structure of low-dimensional semiconductors. We have found improved versions of these techniques: soft contact electroreflectance and soft contact surface photovoltage which offer operational advantages as well as extend the range of these spectroscopies. We also provide analytic formulation for extracting the transition parameters from the measured surface photovoltage spectrum of a quantum structure.     

Experimental and numerical characterization of shape memory polymer and metal laminates

The interface strength of a Shape Memory Polymer – Stainless Steel (SMP-SS) laminate system has been studied under a wide range of test conditions. The adhesive strength of the laminates has been explored using the peel test at room temperature as well as the glass transition temperature of the SMP. The analysis was also repeated at varying speeds and SMP thickness in order to quantify the effect of strain rate and adherend thickness on the bond strength of the laminate.

The experimental tests have been validated using finite element analysis of the SMP – SS laminate system. The finite element study further explores the role of polymer stresses and strains in the polymer film and adhesive layer in inducing delamination and wrinkling.

Significant decrease in strains in the adherend are observed on increasing its thickness. The adhesive strength of the laminate system is found to decrease at higher temperatures. Also the adherend is observed to wrinkle at longitudiunal strains nearing 35%.     

Tribological Behavior of Al-SiC Metal Matrix Composite Under Dry,Aqueous and Alkaline Medium

The present study considers friction and wear behavior of aluminum matrix composites reinforced with SiC particles under three different working environments, viz., dry condition, aqueous medium and alkaline medium. The experiments are conducted with a pin-on-disk tribotester where the composite specimen slides against an alumina disk under the application of varying normal load and sliding speed. It is observed that wear increases with increase in applied load and sliding speed for all three working environments and the maximum wear occurs in the case of the alkaline medium followed by the aqueous medium and the dry condition. In general, the friction coefficient decreases with increase in applied normal load. The microstructure analysis of the worn sliding surface is done with the help of a scanning electron microscope and energy dispersive X-ray analysis. It is seen that the wear mechanism in dry condition is dominated by adhesive and abrasive wear while both mechanical and corrosive wear occur in corrosive environments.     

Defect analysis of thin film Si-based alloys deposited by hot-wire CVD using junction capacitance methods

We evaluate and compare the electronic properties of hot-wire CVD deposited a-Si:H and a-Si,Ge:H films with those produced by the glow discharge (PECVD) method. A good indicator of film quality with respect to solar cell applications is the narrowness of the band tail widths determined by transient photocapacitance (TPC) spectroscopy. We focus on the excellent electronic properties of hot-wire CVD a-Si,Ge:H alloys that have recently been produced by a 1800  °C filament temperature process. These alloy samples were compared to a-Si,Ge:H films of the same optical gaps deposited by PECVD. Light-induced degradation was examined in a few samples and compared to the behavior PECVD a-Si,Ge:H alloys of similar optical gap. The effects of intentional oxygen contamination were also studied on a series of HWCVD a-Si,Ge:H samples containing 29at.% Ge.     

Modified cuckoo search algorithm in microscopic image segmentation of hippocampus

Microscopic image analysis is one of the challenging tasks due to the presence of weak correlation and different segments of interest that may lead to ambiguity. It is also valuable in foremost meadows of technology and medicine. Identification and counting of cells play a vital role in features extraction to diagnose particular diseases precisely. Different segments should be identified accurately in order to identify and to count cells in a microscope image. Consequently, in the current work, a novel method for cell segmentation and identification has been proposed that incorporated marking cells. Thus, a novel method based on cuckoo search after pre‐processing step is employed. The method is developed and evaluated on light microscope images of rats’ hippocampus which used as a sample for the brain cells. The proposed method can be applied on the color images directly. The proposed approach incorporates the McCulloch's method for lévy flight production in cuckoo search (CS) algorithm. Several objective functions, namely Otsu's method, Kapur entropy and Tsallis entropy are used for segmentation. In the cuckoo search process, the Otsu's between class variance, Kapur's entropy and Tsallis entropy are employed as the objective functions to be optimized. Experimental results are validated by different metrics, namely the peak signal to noise ratio (PSNR), mean square error, feature similarity index and CPU running time for all the test cases. The experimental results established that the Kapur's entropy segmentation method based on the modified CS required the least computational time compared to Otsu's between‐class variance segmentation method and the Tsallis entropy segmentation method. Nevertheless, Tsallis entropy method with optimized multi‐threshold levels achieved superior performance compared to the other two segmentation methods in terms of the PSNR.     

The MSK: a simple and robust image encryption method

Multimedia Tools and Applications - This article proposes a new image encryption approach based on bitplane decomposition methods and chaotic maps. This approach does not depend on any additional...     

WTAOF-ILPB Based Feature Learning and LFSSOA-RBFNN Based Classification for Facial Micro-Expression Recognition

Wireless Personal Communications - The cloud computing paradigm offers several services to handle a large amount of data. These services include data storage, exploration, and analysis. Due to the...