Adaptive Data Hiding,Using Pixel-Value-Differencing and LSB Substitution

With the development of Internet communications, the security of message sending on the Internet has become very important. This article proposes a new adaptive data hiding method with a large data-embedding capacity for gray-scale images to raise the security of sending a message between sender and receiver in networks. At first, the image is divided into some blocks consisting of two consecutive pixels. If the values of both pixels are small, fewer secret bits will be embedded within the two pixels, otherwise, the difference value of two pixels is calculated, and according to the obtained difference value, the method will estimate the number of embedding bits into LSBs of two pixels. This number is adaptive and depends on the range to which the difference value belongs. A readjusting phase is presented to keep the difference of value pixels in the same range before and after embedding. Experimental results show that our method has increased the capacity of embedding bits in comparison with the several other methods.     

A high-resolution time-resolved study of incoherent interface motion during the massive transformation in TiAl alloy

Frame-by-frame analyses of in-situ high-resolution transmission electron microscope (HRTEM) heating experiments performed on a high-index incoherent massive transformation interface in TiAl alloy at 575°C show that the interface displays dynamic fluctuations in its trace that can be described in terms of a wavelike function with an amplitude of 0.21 nm and a fundamental wavelength of 1.15 nm. The interface moves forward with a constant average velocity of 0.023 nm/s, due to spreading of criticalsize advancing fluctuations along the interface at different locations, which causes it to remain relatively planar as it advances. This interface behavior is remarkably similar to that observed during previous in-situ optical microscopy studies on massive transformation interfaces in Cu−Ga alloy and is distinctly different from the behavior of highly faceted interphase boundaries. This article is based on a presentation made in the “Hume-Rothery Symposium on Structure and Diffusional Growth Mechanisms of Irrational Interphase Boundaries,” which occurred during the TMS Winter meeting, March 15–17, 2004, in Charlotte, NC, under the auspices of the TMS Alloy Phases Committee and the co-sponsorship of the TMS-ASM Phase Transformations Committee.     

A high-resolution time-resolved study of incoherent interface motion during the massive transformation in TiAl alloy

Frame-by-frame analyses of in-situ high-resolution transmission electron microscope (HRTEM) heating experiments performed on a high-index incoherent massive transformation interface in TiAl alloy at 575 °C show that the interface displays dynamic fluctuations in its trace that can be described in terms of a wavelike function with an amplitude of 0.21 nm and a fundamental wavelength of 1.15 nm. The interface moves forward with a constant average velocity of 0.023 nm/s, due to spreading of critical-size advancing fluctuations along the interface at different locations, which causes it to remain relatively planar as it advances. This interface behavior is remarkably similar to that observed during previous in-situ optical microscopy studies on massive transformation interfaces in Cu-Ga alloy and is distinctly different from the behavior of highly faceted interphase boundaries. This article is based on a presentation made in the “Hume-Rothery Symposium on Structure and Diffusional Growth Mechanisms of Irrational Interphase Boundaries,” which occurred during the TMS Winter meeting, March 15–17, 2004, in Charlotte, NC, under the auspices of the TMS Alloy Phases Committee and the co-sponsorship of the TMS-ASM Phase Transformations Committee.     

Application of the meta-heuristics for optimizing exergy of a HT-PEMFC

The aim of this study is to analyze the exergy efficiency of a high-temperature proton exchange membrane fuel cell. To do this purpose, meta-heuristic technique has been used. First, the model of a membrane fuel cell is simulated and the polarization diagram shows a potent agreement with empirical data. Then, a new improved version of collective animal behavior algorithm is utilized for evaluating and optimizing the thermodynamic irreversibility, exergy efficiency, and work of the fuel cell. The algorithm uses opposition-based learning and Lévy flight for improving the algorithm's premature convergence shortcoming. The result of this study shows that by comparison with standard collective animal behavior algorithm, genetic algorithm, and empirical results, the proposed algorithm has better achievements for both terms of optimal value finding and convergence strength.