Anoop Tiwari

A Comparison of Peak to Average Power Reduction Schemes for OFDM

In this paper we are introduced newly but powerful and less noisy peak to average power reduction techniques for Orthogonal Frequency Division Multiplexing (OFDM). These two techniques are comparing and show its results. One investigated technique is Threshold selected mapping (TSLM).In this scheme the transmitted signal is minimum PAPR by thresholding a selected signal from a set of signals and the another investigated technique is modernized selected mapping (MSLM). In this scheme the transmit signal is separate in two part real and imaginary then selected from minimum PAR of each set of signals. This real and imaginary combined. They both techniques introduce some computational complexity. The comparisons of TSLM and MSLM schemes are by simulation results.

Sediment composition and its effect on the productivity in Larsemann Hills, East Antarctica

The sediment cores collected from lakes L-8, L-10, and L-12 of Larsemann Hills, East Antarctica, were investigated for sediment components (sand, silt, clay, total organic carbon, total nitrogen, total phosphorus, elemental TOC/TN ratio, and biogenic silica or biogenic opal), major elements (Al, Fe, Mn, Ti, Mg, Ca), and trace metals (Cr, Co, Zn, Cd, Pb, Ba, Cu, Ni) to understand the source, processes, and productivity in the lacustrine sediments. In lake L-10, average sand content was higher than in lakes L-8 and L-12 which indicated the high intensity of mechanical weathering, resulted in releasing coarse-grained material from the rocks in the catchment area. High Ti/Al molar ratios (2.00–3.32) in all the three cores resulted from shorter transportation distance from different parent sources. Higher clay content near the surface in all the three lakes indicated deposition of fine-grained particles supplied by ice-melt water owing to ice-free conditions in the area in recent years. Relatively, higher biogenic silica along with high total organic carbon associated with high clay in the upper section of lakes L-10 and L-12 and middle section of core L-8 indicated deposition of finer particles from suspension which facilitated high primary productivity due to exposure of the lakes to the ice-melt water influx. Further, Mg/Ca ratio in all the three lakes was high near the surface indicating enrichment of biogenic sedimentation. C/N ratio was found to be much less than 10, indicating the major source of organic matter is autochthonous and exclusively derived from algae (C/N < 10) in all the cores. The metal concentration was found to be higher in core L-8 and was found to be associated with finer sediments, as compared to cores L-10 and L-12 where coarser sediments must have diluted the metal content. Ba was found to be of biogenic origin in cores L-8 and L-12 while in core L-10 it was of lithogenic origin. Cd, Zn, and Ni in all the three lakes were found to be mainly of biogenic origin, whereas all other metals studied were of lithogenic origin. Thus, the concentration of trace metals in Larsemann Hill lake sediments is entirely by natural processes regulated by lithology, catchment processes, and climatic conditions.

A Robust Method for Image Steganography based on Chaos Theory

The Internet provides very economical real-time communications between computers and delivers services/products almost instantly to the users. The sensitive data transmitted through the internet must be secured as it is growingly susceptible to security related problems such as eavesdropping, malicious interventions etc. The steganography is an alternative to cryptographic techniques for secured transmission of data over the internet, where the secret message is hidden in some other innocuous communication so that only the rightful recipient can able to detect the presence of the secret message and extract it. Recently, many data embedding schemes have been proposed for achieving the robustness of this technique. However, most of the schemes lack to strike a tradeoff between the embedding capacity and the visual quality. In this paper, we have proposed a new method for hiding messages in a color image in the spatial domain based on chaos theory, which uses chaotic maps to embed data. This method is robust as well as has the higher payload capacity and compression resistant.

Linear Block Equalizers in Rayleigh Fading Channel with Normalized Channel Impulse Response

Linear adaptive equalizers are widely used in wireless communication systems in order to reduce the effects of the channel distortion. Various researchers have used linear block equalizers for different modulations techniques. In this paper the BER performance of different M-PSK and M-QAM modulations with the block based LMS and RLS linear equalizers are compared over the flat and frequency selective Rayleigh fading channel. For achieving better performance the Rayleigh channel is modeled with four multipath channels and normalized channel impulse response under the presence of AWGN noise. The maximum Doppler shifts frequencies are varied for evaluating the performance of the equalizers. Using the normalized channel impulse response improves the BER performance of the communication system for the higher values of M as 512 and 1024. Transmitted and received constellation diagrams are also compared for different equalizers. Performance is also compared for the different equalizer weights and block sizes. General Terms Adaptive Equalizers, Rayleigh fading channel, Wireless communication

A Mixed Model Binary Imaging Strategy Using Wireless Sensors for Brain Imaging

Cognitive radio is a new paradigm for wireless communications offering a solution to conciliate the current spectrum demand growth and underutilization without changes to the existing legacy wireless systems. Segmentation of brain structures from MR images is crucial in understanding the disease progress, diagnosis, and treatment monitoring. Atlases, showing the expected locations of the structures, are commonly used to start and guide the segmentation process. Classification of complex motor activities from brain imaging is relatively new in the fields of neuroscience and brain-computer interfaces (BCIs). In many cases, the quality of the atlas may have a significant effect in the final result. In this paper we propose a novel mixed model Binary Imaging Strategy using Wireless Sensors for brain imaging. In this technique we first segmented the images and deform with the manual contour. Our study shows that the expected result is good in various areas.

Primal Remonstrance Evolution of NIR Single Chip Optical Sensor for Mental Tomography and their Practicability

The brain is arguably, the least understood of all the major organs in the human body. While the basic physical structure of the brain and the functioning of separate mental domains and cells inside have been understood for some time, our agreement of the mental functioning as a Research system is still largely taking shape. Here the internal optical signalling based monolithic sensor pops the questions as to feasibility. First, the use of NIR light due to less optical absorption. It shows low signalling level compared to visible light. Another challenge of resolution, due to low signals system designing is also a big call out. Also the small spatial scales of a monolithic IC are a great challenge. In this paper we have discuss the work guarantee the assess the extent of these challenges. A combination of experimental study and computer simulation shows that these challenges can be met and that a monolithic internal optical signalling tomography sensor is fundamentally feasible General Terms Optical Sensor Technology