Terahertz Magneto Optical Polarization Modulation Spectroscopy

We report the development of new terahertz techniques for rapidly measuring the complex Faraday angle in systems with broken time-reversal symmetry using the cyclotron resonance of a GaAs two-dimensional electron gas in a magnetic field as a system for demonstration of performance. We have made polarization modulation, high sensitivity (< 1 mrad) narrow band rotation measurements with a CW optically pumped molecular gas laser, and by combining the distinct advantages of terahertz (THz) time domain spectroscopy and polarization modulation techniques, we have demonstrated rapid broadband rotation measurements to < 5 mrad precision.Comment: 25 pages including 7 figures, introduces use of rotating polarizer with THz TDS for Complex Faraday Angle determinatio

Household, community, sub-national and country-level predictors of primary cooking fuel switching in nine countries from the PURE study

Introduction. Switchingfrom polluting (e.g. wood, crop waste, coal)to clean (e.g. gas, electricity) cooking fuels can reduce household air pollution exposures and climate-forcing emissions.While studies have evaluated specific interventions and assessed fuel-switching in repeated cross-sectional surveys, the role of different multilevel factors in household fuel switching, outside of interventions and across diverse community settings, is not well understood. Methods.We examined longitudinal survey data from 24 172 households in 177 rural communities across nine countries within the Prospective Urban and Rural Epidemiology study.We assessed household-level primary cooking fuel switching during a median of 10 years offollow up (∼2005–2015).We used hierarchical logistic regression models to examine the relative importance of household, community, sub-national and national-level factors contributing to primary fuel switching. Results. One-half of study households(12 369)reported changing their primary cookingfuels between baseline andfollow up surveys. Of these, 61% (7582) switchedfrom polluting (wood, dung, agricultural waste, charcoal, coal, kerosene)to clean (gas, electricity)fuels, 26% (3109)switched between different polluting fuels, 10% (1164)switched from clean to polluting fuels and 3% (522)switched between different clean fuels

DESIGN AND DEVELOPMENT OF COMPACT ASYMMETRIC COPLANAR STRIP FED ANTENNAS

Antennas are indispensable component of any wireless communication device. An antenna is a transducer between the transmitter and the free space waves and vice versa. They efficiently transfer electromagnetic energy from a transmission line into free space. But the present day communication applications require compact and ultra wide band designs which cannot be catered by simple microstrip based designs. PIFAs have solved the problem to some extend, but the field of antennas needs more innovative designs In this thesis the design and development of compact planner antenna are presented. Emphasis is given to the design of the feed as well as the radiator resulting in simple compact uniplanar geometries. The Asymmetric coplanar feed used to excite the antennas is found to be a suitable choice for feeding compact antennas.The main objectives of the study are the design of compact single, dual and multi band antennas with uniplanar structure and extension of the design for practical GSM/WLAN applications and Ultra compact antennas using the above techniques and extension of the design to antennas for practical applications like RFID/DVB-H. All the above objectives are thoroughly studied. Antennas with ultra compact dimensions are obtained as a result of the study. Simple equations are provided to design antennas with the required characteristics. The design equations are verified by designing different antennas for different applications.Department of Electronics, Cochin University of Science and Technolog

A review of literature on implementation and operational dimensions of supply chain digitalization: Framework development and future research directions

Supply chain digitalization (SCD) significantly improves supply chain performance. This article reviews the literature on the implementation and operational dimensions of SCD. The review was conducted by analyzing the publications in SCD from 2013 to 2022. A systematic literature review of 102 publications in SCD and thematic analysis was employed in this study. The key implementation and operational dimensions, research streams, and gaps in the literature on SCD were identified. A conceptual framework for SCD is also presented. This study has attempted to summarize the literature on key implementation and operational dimensions state-of-art literature in SCD. Gaps in literature were identified and grouped categorically for better understanding and further investigations. This study could benefit industry practitioners and academicians in the logistics and supply chain community

PIXEL PATTERN BASED STEGANOGRAPHY ON IMAGES

One of the drawback of most of the existing steganography methods is that it alters the bits used for storing color information. Some of the examples include LSB or MSB based steganography. There are also various existing methods like Dynamic RGB Intensity Based Steganography Scheme, Secure RGB Image Steganography from Pixel Indicator to Triple Algorithm etc that can be used to find out the steganography method used and break it. Another drawback of the existing methods is that it adds noise to the image which makes the image look dull or grainy making it suspicious for a person about existence of a hidden message within the image. To overcome these shortcomings we have come up with a pixel pattern based steganography which involved hiding the message within in image by using the existing RGB values whenever possible at pixel level or with minimum changes. Along with the image a key will also be used to decrypt the message stored at pixel levels. For further protection, both the message stored as well as the key file will be in encrypted format which can have same or different keys or decryption. Hence we call it as a RGB pixel pattern based steganography

DIGITAL DATA PROTECTION USING STEGANOGRAPHY

In today’s digital world applications from a computer or a mobile device consistently used to get every kind of work done for professional as well as entertainment purpose. However, one of the major issue that a software publisher will face is the issue of piracy. Throughout the last couple of decades, almost all-major or minor software has been pirated and freely circulated across the internet. The impact of the rampant software piracy has been huge and runs into billions of dollars every year. For an independent developer or a programmer, the impact of piracy will be huge. Huge companies that make specialized software often employ complex hardware methods such as usage of dongles to avoid software piracy. However, this is not possible to do for a normal independent programmer of a small company. As part of the research, a new method of software protection that does not need proprietary hardware and other complex methods are proposed in this paper. This method uses a combination of inbuilt hardware features as well as steganography and encryption to protect the software against piracy. The properties or methods used include uniqueness of hardware, steganography, strong encryption like AES and geographic location. To avoid hacking the proposed framework also makes use of self-checks in a random manner. The process is quite simple to implement for any developer and is usable on both traditional PCs as well as mobile environments