An image encryption approach using tuned Henon chaotic map and evolutionary algorithm

A new evolutionary-based image encryption method is proposed to protect the image content against adversary attacks from an insecure network throughout the Internet. Two-dimensional Henon chaotic map is the significant part of the encryption process, whereas its performance strongly depends on the fine tuning of its parameters, including α and β. Imperialist Competitive Algorithm (ICA) is applied to determine these parameters based on the input simple image, so that the pseudorandom number generated by the two-dimensional Henon map would be unique for each simple image, making it difficult to explore the encryption process. Experimental results assert that the proposed method is secure enough to resist against common attacks.

     

An electrostatically actuated microsensor for determination of micropolar fluid physical properties

Meccanica - Micropolar fluids as complex non-Newtonian fluids admittedly have numerous applications in various fields, especially in medicine. Blood as a micropolar fluid plays an important role in...     

Analysis of spatial transform motion estimation with overlappedcompensation and fractional-pixel accuracy

The authors investigate how the performance of spatial transform motion estimation can be significantly improved by incorporating overlapped compensation and fractional-pixel accuracy. An overlapped spatial transformation (OST) motion model is developed, which successfully addresses the inability of the conventional block matching technique to compensate for complex motion and inside-block motion field discontinuities. Simulation results show that the motion compensated prediction error of this method is reduced by 1.1 dB, compared with the conventional overlapped block matching motion estimation, for the same generated motion vectors overhead. To improve the performance, the overlap must be used in both the motion estimation and compensation processes. Further improvement can be obtained using half-pixel precision motion vectors. However, this improvement is comparatively less than the gain of conventional block matching from a half-pixel search     

Vibrational analysis of the fullerene family using Tersoff potential

Using Tersoff bond order potential, a vibrational analysis of the spherical fullerene family, namely C₆₀, C₈₀, C₁₈₀, C₂₄₀, C₂₆₀, C₃₂₀, C₅₀₀, and C₇₂₀ was performed. To evaluate the validity of our results, we have compared our simulation results with available experimental data and also with DFT B3LYP/6-31G(d) calculations. In general, molecular stiffness tends to decrease with increasing size, but its variation is limited in cases where mostly the tension-compression interaction sites are active such as the breathing mode. Furthermore, the bond length of each molecule is derived and compared with experimental and theoretical values calculated for graphene. Finally, vibrational frequencies are plotted in a histogram to reveal the common frequency gap and concentration points of the frequency distribution.     

A class of adaptive Dai–Liao conjugate gradient methods based on the scaled memoryless BFGS update

Minimizing the distance between search direction matrix of the Dai–Liao method and the scaled memoryless BFGS update in the Frobenius norm, and using Powell’s nonnegative restriction of the conjugate gradient parameters, a one-parameter class of nonlinear conjugate gradient methods is proposed. Then, a brief global convergence analysis is made with and without convexity assumption on the objective function. Preliminary numerical results are reported; they demonstrate a proper choice for the parameter of the proposed class of conjugate gradient methods may lead to promising numerical performance.     

Triazine-modified magnetite nanoparticles as a novel sorbent for preconcentration of lead and cadmium ions

We report on a new sorbent for preconcentration of cadmium and lead ions that is based on triazine-functionalized magnetite nanoparticles that were prepared by direct silylation of magnetic nanoparticles with 3-aminopropyltriethoxysilane-2,4-bis(3,5-dimethylpyrazol)-triazine. The sorbent was characterized by IR spectroscopy, X-ray powder diffraction, scanning electron microscopy, thermal and elemental analysis. The sorbent was applied to the preconcentration of lead and cadmium ions which then were quantified by FAAS. The effects of sample pH value, extraction time, of type, concentration and volume of eluent, and of elution time were optimized. The limits of detection are 0.7 ng mL^?1 for Pb(II) ion and 0.01 ng mL^?1 for Cd(II). The effects of potentially interfering ions often found in real samples on the recovery in the determination of cadmium and lead ions in real samples were also investigated. The accuracy of the method was confirmed by analyzing the certified reference materials NIST 1571 (orchard leaves) and NIST 1572 (citrus leaves). Finally, the method was successfully applied to the determination of cadmium and lead ions in some fruit samples. Figure

We report on a new sorbent for preconcentration of cadmium and lead ions that is based on triazine-functionalized magnetite nanoparticles. After optimization of the preconcentration step the method was successfully applied to the determination of cadmium and lead ions in some fruit samples     

Efficient packetisation scheme for bluetooth video transmission

The Bluetooth wireless link is likely to be the last hop in the delivery of an encoded streamed video clip. It is shown that it is preferable to optimally map arriving IP packets onto Bluetooth packets than to preserve the stream's internal synchronisation structure. Video quality improves and latency reduces, even when there is cross traffic on the piconet     

Smoothing transcoded MPEG-1 video streams for Internet transmission

An efficient smoothing scheme for the real-time transmission of MPEG-1 transcoded video over 'best-effort' IP networks is presented. The scheme uses intelligent partitioning and multiplexing of the packetised bit stream. Bit-rate smoothing is achieved by partitioning packets according to their picture type (I, P or B). Subsequently, the partitioned packets are multiplexed in such a way that each packet from an anchor (I and P) picture is followed by two packets from B-pictures. The proposed scheme smooths the bit rate of the encoded video, making it more suitable for adaptive video streaming applications. In such applications, the transmission bit rate is varied so as to adapt to the available network bandwidth. The scheme reorganises the transmission order of the packets, spreading the less important packets from the B-pictures into the more important packets from the anchor pictures. This indicates a reduction in the likelihood of losing more important anchor packets as the bandwidth bottleneck increases, implying an improvement in the quality of transmitted video. A variety of simulations results are presented to demonstrate these points.