Robust image watermarking scheme using bit-plane of hadamard coefficients

Multimedia Tools and Applications - Nowadays, due to widespread usage of the Internet, digital contents are distributed quickly and inexpensively throughout the world. Watermarking techniques can...     

Queue Analysis and Multiplexing of Heavy-tailed Traffic in Wireless Packet Data Networks

Recent research based on traffic measurements shows that Internet traffic flows have a fractal nature (i.e., self-similarity property), which causes an underestimation of network engineering parameters when using the conventional Poisson model. Preliminary field measurements demonstrate that packet data traffic in wireless communications also exhibits self-similarity. In this paper, we investigate the queuing behavior of self-similar traffic flows for data applications in a packet-switching single-server wireless network. The traffic is generated by an on–off source with heavy-tailed on periods and exponentially distributed off periods. We extend previous analysis of a relation among the asymptotic distribution of loss probability, traffic specifications, and transmission rate for a wireline system to a wireless system, taking into account wireless propagation channel characteristics. We also investigate the multiplexing of heavy-tailed traffic flows with a finite buffer for the downlink transmission of a wireless network. Computer simulation results demonstrate that assumptions made in the theoretical analysis are reasonable and the derived relationships are accurate.     

Statistical optimization of process conditions for photocatalytic degradation of phenol with immobilization of nano TiO<Subscript>2</Subscript> on perlite granules

Response surface methodology (RSM) using D-optimal design was applied to optimization of photocatalytic degradation of phenol by new composite nano-catalyst (TiO₂/Perlite). Effects of seven factors (initial pH, initial phenol concentration, reaction temperature, UV irradiation time, UV light intensity, catalyst calcination temperature, and dosage of TiO₂/perlite) on phenol conversion efficiency were studied and optimized by using the statistical software MODDE 8.02. On statistical analysis of the results from the experimental studies, the optimum process conditions were as follows: initial pH, 10.7; initial phenol concentration, 0.5 mM; reaction temperature, 27 °C; UV irradiation time, 6.5 h; UV light intensity, 250 W; catalyst calcination temperature, 600 °C; and TiO₂/perlite dosage, 6 g/L. Analysis of variance (ANOVA) showed a high coefficient of determination (R²) of 91.8%.     

Interactive multi-modal suturing

We present a mechanics-based interactive multi-modal environment designed as part of a serious gaming platform. The specific objectives are to teach basic suturing and knotting techniques for simple skin or soft tissue wound closure. The pre-wound suturing target, skin, or deformable tissue is modeled as a modified mass-spring system. The suturing material is designed as a mechanics-based deformable linear object. Tools involved in a typical suturing procedures are also simulated. Collision management modules between the soft tissue and the needle, the soft tissue and the suture are analyzed. In addition to modeling the interactive environment of a typical suturing procedure, basics of the modeling approaches on the evaluation of a stitch formed by the user are also discussed. For example, if needle insertion points are too close from each other or to the edge of the wound, when the suture is pulled, the suture will tear the soft tissue instead of suturing the incision together. Experiment results show that our simulator can run on a standard personal computer and allow users to perform different suturing patterns with smooth graphics and haptic feedback.     

Removal of Diazinon from aqueous solution by electrocoagulation process using aluminum electrodes

Electrocoagulation (EC) is an electrochemical method to treat polluted wastewaters and aqueous solutions. In this paper, the removal of Diazinon was studied by EC on aluminum electrode. The effect of several parameters such as initial concentration of Diazinon, current density, solution conductivity, effect of pH, and electrolysis time were investigated on EC performance. The obtained results showed that the removal efficiency of EC depends on the current density, initial concentration of Diazinon and electrolysis time. The optimum pH is 3 and also the solution conductivity has no significant effect on removal efficiency.     

Polyol-Derived Alkoxide/Hydroxide Base Catalysts II: Transesterification Reactions

Biodiesel, fatty acid methyl ester (FAME), was produced by transesterification of canola oil with methanol in the presence of a series of alkoxide/hydroxide base catalysts produced from glycerol, 1,2-propanediol, 1,3-propanediol, xylitol, or sorbitol produced by dehydration reaction of sodium hydroxide in the presence of polyols. Transesterification reactions proceeded efficiently in the presence of sodium alkoxide catalysts prepared at three different mole ratios of sodium hydroxide to glycerol (1:1, 2:1, and 3:1). The production of methyl ester during the course of the reaction was determined repeatedly and the reaction progress was compared with that achieved in a reaction catalyzed by freshly prepared anhydrous sodium methoxide as a standard catalyst. Sodium alkoxide/hydroxide catalysts activity during the first 2 min of the reaction was in the order of: sorbitol < xylitol < sodium methoxide < 1,2-propanediol < 1,3-propanediol < glycerol regardless of the mole ratio of sodium hydroxide to glycerol. All catalysts showed a higher methyl ester accumulation at higher ratios of sodium hydroxide to polyol and had the following order 1:1 < 2:1 < 3:1 (sodium hydroxide:glycerol). Several of these catalysts were as powerful as sodium methoxide in catalyzing the transesterification reaction at the same mole concentration. All alkoxide/hydroxide catalysts resulted in a high FAME accumulation (>95 wt%) in a single transesterification batch reaction.     

Active only integrator and differentiator with tunable time constants

In this paper new active only current-mode integrator and differentiator with electronically tunable time constants are described. They are composed of one operational amplifier (OA) and two operational transconductance amplifiers (OTAs), and are suitable for monolithic implementation either with CMOS or bipolar technologies. No realizability conditions are imposed for the proposed circuits and all of the active sensitivities are low. The performances of the circuits are demonstrated on the PSPICE platform.     

Effect of micronisation and electromagnetic radiation on physical and mechanical properties of Canadian barley

The effect of micronisation (high‐intensity infrared heating) and microwave radiation of normal barley (NB), high‐amylose barley (HAB) and waxy barley (WB) on the physical and mechanical properties was studied. Samples were tempered to 42–45% moisture content and then subjected to infrared or microwave radiation to reduce the moisture content to approximately 10%. The grain surface temperature during radiation was maintained at 100 °C. The changes in physical and mechanical properties were compared with unprocessed samples. Thermal radiation increased slightly the volume of the kernels because of the diffusion of water vapour from inside to the outer surface. These changes resulted in a decrease in particle and bulk densities. Thermal radiation affected the Hunter colour values, as well. The mechanical properties including bio‐yield point, modulus of elasticity and breakage susceptibility were affected by micronisation and microwave heating.