Informatics Publishing Limited

D. Senthil Kumar ¹, N. Kumaratharan ¹

Affiliations
1 Information Technology Department, Sri Venkateswara College of Engineering, Sriperumbudur, Tamil Nadu, IN

Abstract

Frequency hopping code division multiple access is a technique which provides high security in the wireless communication. Different types of code sequencing techniques are used for the frequency hopping. The prime codes are only coded in the time domain. However, the small code size becomes the major issue for one-dimensional codes. To deal with this limitation of one dimensional codes, a new family of two-dimensional codes is proposed. The new codes are modified from the well known prime-hop codes. Hence, it is referred as multilevel prime codes. The modified prime-hop codes preserve the same code correlation properties as the original prime-hop codes, i.e. the cross-correlating constraint is equal to one and the autocorrelation constraint is equal to zero, and can be generated with lower cost, lower complexity and lower power loss encoders/decoders.

Keywords

Frequency Hopping-Code Division Multiple Access, Multilevel Prime Code, Multiple Access Interference, Prime Code.

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R. Vishnu Varthan ¹, D. Senthil Kumar ¹

Affiliations
1 Department of Mechanical Engineering, Amrita School of Engineering, Amrita Vishwa Vidyapeetham, Amrita University, Coimbatore – 641112, Tamil Nadu, IN

Abstract

Fossil fuel reserves are depleting at an alarming rate and may become extinct in few decades. To counteract this crisis much emphasis is laid out on usage of alternate fuels. Also techniques like turbocharging are used to increase the efficiency of the IC engines thereby reducing the fuel consumption. While opting for such alternate solutions like biodiesel and turbocharging, the exhaust emissions should be checked to ensure that these solutions don’t pose a threat to the environment. So in this project the change in amount of component gases in the exhaust emissions were found out in four cases which are naturally aspirated with diesel, turbocharged with diesel, naturally aspirated with biodiesel and turbocharged with biodiesel. A single cylinder motorcycle diesel engine is used in this project. Emission characteristic tests were done in the naturally aspirated engine using diesel and biodiesel as fuels. Then a turbocharger designed for this engine is fitted to it and the same tests as above were conducted. Comparison in exhaust emissions which are NO_x, HC, CO and CO₂ was made for the above mentioned four cases. It was found that NOx emissions has increased by the usage of biodiesel as fuel, while turbocharger has decreased the NO_x levels. This is a concern to be addressed while using biodiesel as alternate fuel. Biodiesel and turbocharger both had a positive effect on HC emissions, i.e. reduced the HC emissions. The impact of biodiesel and turbocharger on CO emissions was not so significant with the former increasing the emissions and the latter decreasing it by providing more oxygen. Though CO₂ is not categorised as toxic emissions like other emissions; it is important to compare the amount emitted in the different cases. Biodiesel increases the amount of less-toxic CO₂ whereas turbocharger has reduced the CO₂ emissions. This is because the excess oxygen provided by turbocharging is used for the formation of water vapour rather than CO₂. Thus the important four emissions were compared to appreciate the effect of biodiesel and turbocharger. In future work the problem of increase in NOx by biodiesel fuel should be addressed and solution has to be formulated.

Keywords

Cotton Seed Methyl Ester, Diesel Engine Emission, Turbocharger

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P. Subathra ¹, A. Baskar ¹, D. Senthil Kumar ²

Affiliations
1 Department of Computer Science and Engineering, Amrita School of Engineering, IN
2 Department of Computer Science and Engineering, Anna University of Technology, Tiruchirappalli, IN

Abstract

Nowadays, digital images can be easily altered by using high-performance computers, sophisticated photo-editing, computer graphics software, etc. It will affect the authenticity of images in law, politics, the media, and business. In this paper, we proposed a Resampling technique using automatic selection of Region of Interest (ROI) method for finding the authenticity of digitally altered image. The proposed technique provides better results beneath scaling, rotation, skewing transformations, and any of their arbitrary combinations in image. It surmounts the protracted complexity in manual ROI selection.

Keywords

Digital Forensics, Interpolation, Resampling Detection, Auto-ROI.

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