456 research outputs found
Synthesis of Novel Nano-Strawberry TiO2 Structures with the Aid of Microwave Inverter System: Growth Time Effect on Optical Absorption Intensity
A novel anatase TiO2 with nanostrawberry-like structure with high porosity has been synthesised on ITO, with the aid of microwave power in a very short duration of 6 minutes. The growth of these novel TiO2nanostructures on ITO is attained stoichiometrically by using ammonium hexafluoro titanate, Hexamethylenetetramine, and Boric acid as precursor, capping agent, and reducing agent, respectively. Optical absorption intensity and thickness of these nanostructure layers can be varied by the growth time. A highly porous, 2.25 µm thickest layer has been successfully synthesised on ITO, and the average diameter of these nanostructures was found approximately 70±2.5nm. These highly porous nanostructures are expected to be good candidate for photocatlysis applications and efficient photovoltaic performances of dye sensitised solar cells
Digital rights management techniques for H.264 video
This work aims to present a number of low-complexity digital rights management (DRM) methodologies for the H.264 standard. Initially, requirements to enforce DRM are analyzed and understood. Based on these requirements, a framework is constructed which puts forth different possibilities that can be explored to satisfy the objective. To implement computationally efficient DRM methods, watermarking and content based copy detection are then chosen as the preferred methodologies.
The first approach is based on robust watermarking which modifies the DC residuals of 4×4 macroblocks within I-frames. Robust watermarks are appropriate for content protection and proving ownership. Experimental results show that the technique exhibits encouraging rate-distortion (R-D) characteristics while at the same time being computationally efficient.
The problem of content authentication is addressed with the help of two methodologies: irreversible and reversible watermarks. The first approach utilizes the highest frequency coefficient within 4×4 blocks of the I-frames after CAVLC en- tropy encoding to embed a watermark. The technique was found to be very effect- ive in detecting tampering. The second approach applies the difference expansion (DE) method on IPCM macroblocks within P-frames to embed a high-capacity reversible watermark. Experiments prove the technique to be not only fragile and reversible but also exhibiting minimal variation in its R-D characteristics.
The final methodology adopted to enforce DRM for H.264 video is based on the concept of signature generation and matching. Specific types of macroblocks within each predefined region of an I-, B- and P-frame are counted at regular intervals in a video clip and an ordinal matrix is constructed based on their count. The matrix is considered to be the signature of that video clip and is matched with longer video sequences to detect copies within them. Simulation results show that the matching methodology is capable of not only detecting copies but also its location within a longer video sequence. Performance analysis depict acceptable false positive and false negative rates and encouraging receiver operating charac- teristics. Finally, the time taken to match and locate copies is significantly low which makes it ideal for use in broadcast and streaming applications
Chromium induced changes in growth and physiological attributes of Chicory (Cichorium intybus L), an important medicinal plant
This study was conducted to determine the impact of different concentrations (25, 37.5 and 50 mg kg-1 soil) of chromium (Cr) on growth, photosynthetic pigments, protein content, proline content, activities of antioxidant enzymes and seed yield of Cichorium intybus in a pot experiment. The results revealed that all the Cr treatments significantly (P </= 0.05) reduced the growth, photosynthetic pigments (chlorophyll a, chlorophyll b and total chlorophyll and carotenoids contents), protein content and seed yield in C. intybus. The activities of catalase (CAT), superoxide dismutase (SOD), peroxidase (POD) and proline content in C. intybus leaves increased significantly (P </= 0.05) with increasing levels of Cr treatments. Cr accumulation was found greater in the roots than in the shoots and enhanced with increasing Cr concentrations. Hence, C. intybus may serve as a bio-meter of Cr in Cr contaminated soils
A Bayesian Approach to Survival Analysis of Gompertz Model with R and JAGS
The Gompertz distribution of lifetimes was introduced in 1825 and a probability model was derived for studying human mortality. In this paper, an attempt has been made to Bayesian fitting of Gompertz distribution. The Bayesian approach is implemented with R and JAGS for analytic and simulation tools. Our main target is to explore the use of Laplace Approximation for Bayesian analysis. A real right censored data is used. Finally, the model is compared with Weibull distribution using Bayesian prediction tools
Bayesian estimation using Lindley’s approximation of Inverted Kumaraswamy distribution based on lower record values
In this paper, we have considered estimation of unknown parameters based on lower record values for Inverted Kumaraswamy distribution. Maximum likelihood and approximate Bayes estimators based on lower record values for unknown parameters of this distribution are obtained. Lindley’s approximation (L-approximation) is used to obtain approximate Bayes estimators under DeGroot loss function based on lower record values. A Simulation study and a real data analysis are presented to illustrate the results.Publisher's Versio
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