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In this paper, a novel watermarking technique for the tamper detection of text images is pro- posed. Entropy of every sentence is computed and Markov matrix using the occurrences of the characters is used to generate a character pattern. Entropy and character patterns are converted to Unicode Zero Width Characters (ZWCs) by using a lookup table. The ZWCs of entropy of each sentence is embedded at the end of every sentence after terminator. ZWCs of the character patterns are embedded in the end of the text of the image. On receiver side, ZWCs are extracted and converted to numerical form using the same lookup table. Entropy of every sentence and character patterns are recalculated and compared with extracted values for tamper detection. Comparison of technique with existing state-of-art techniques shows the effectiveness of the proposed technique.

Existing tamper detection techniques for document images use the textual information of the image to create a zero watermark. These techniques cannot authenticate a document image if the image is tampered with in non-textual regions. In order to resolve this problem, a tamper detection technique for document images is proposed using the concept of zero watermarking. The input document image is transformed by applying lifting wavelet transform to get its subbands. These subbands are further partitioned into non-overlapping blocks of the same size. Features of each blocks are extracted to create a zero watermark. This watermark is combined with the key watermark in order to create a meaningful watermark. This meaningful watermark is stored by a trusted authority. On the receiver side, the meaningful watermark is compared to the watermark generated using tampered image to check the authenticity of the cover image. The tampered regions of the cover image can also be localized using this technique. The experimental results demonstrate the effectiveness of the technique in comparison to the existing authentication techniques.

A novel thermotolerant Streptomyces sp. ssr-198 with capacity to produce multicomponent holocellulolytic enzymes was isolated and identified using 16S rDNA sequencing. Important chemical components of medium were optimized by rotatable central composite design (RCCD) using response surface methodology (RSM) to achieve maximal yield of holocellulolytic (endoglucanase, exoglucanase and xylanase) enzymes. Optimization resulted in 246%, 83%, and 96% higher yield of endoglucanase, exoglucanase and xylanase respectively as compared to unoptimized conditions. The concentrated crude enzymes were partially characterized in terms of optimum pH (6.0) and temperature (60 °C). Multiple endoglucanase and xylanases with diverse molecular weights were detected in the zymogram. The study demonstrated the ability of this newly isolated Streptomyces strain to produce a high titer of holocellulolytic enzymes with potential application in the saccharification of lignocellulosic biomass.

This paper presents the performance analysis of interior permanent magnet synchronous motor (IPMSM) fed from improved power quality converter–inverter system as a variable speed drive for air-conditioning (Air-Con). The improved power quality converter (IPQC) makes the input power factor unity and also reduces the total harmonic distortion (THD) of input supply current. This converter consists of two uncontrolled unidirectional and two bi-directional switches. It provides constant DC-link voltage during transient and steady state conditions. This converter has high efficiency as only two switches conduct at a time and IPMSM also offers high efficiency as compared to other electric motors. The proposed drive system is an appropriate solution for energy conservation in the AC distribution system, in the motor and in the compressor of Air-Con. The detailed model and the simulated results of the proposed drive system are presented to demonstrate the features of improved power quality and energy conservation.