Mallikarjuna K.,RGMCET |
Satya Prasad K.,JNTUK |
International Journal of Applied Engineering Research | Year: 2015
For the purpose of image coding and compression, many algorithms are available in the existing literature. As an alternative to these traditional approaches, in this paper, we have used Discrete Rajan Transform for sparsification and image compression. On simulation, it was observed that Discrete Rajan Transform yielded higher quality image than the other candidate transforms used, namely Discrete Cosine Transform and Discrete Wavelet Transform. While the Discrete Cosine Transform gives better compression ratio, the image quality degrades because of the artifacts that result from the transform. Discrete Rajan Transform is effective in introducing sparsity in images and thereby improving compressibility, the compromise being a loss of data. The Peak Signal to Noise Ratio is better in comparison with the other candidate transforms used in this research. © Research India Publications.
Rao S.N.,RGMCET |
Kumar D.V.A.,SDIT |
Proceedings of 2013 International Conference on Power, Energy and Control, ICPEC 2013 | Year: 2013
This paper presents a new class of three phase seven level inverter based on a multilevel DC link (MLDCL) and a bridge inverter to reduce the number of switches. There are 3 types of multilevel inverters named as diode clamped multilevel inverter, flying capacitor multilevel inverter and cascaded multilevel inverter. Compared to diode clamped & flying capacitor type multilevel inverters cascaded H-bridge multilevel inverter requires least no. of components to achieve same no of voltage levels and optimized circuit layout is possible because each level have same structure and there is no extra clamping diodes or capacitors. However as the number of voltage levels m grows the number of active switches increases according to 2×(m-1) for the cascaded H-bridge multilevel inverters. Compared with the existing type of cascaded H-bridge multilevel inverter, the proposed MLDCL inverters can significantly reduce the switch count as well as the number of gate drivers as the number of voltage levels increases. For a given number of voltage levels, the required number of active switches is 2 (m-1) for the existing multilevel inverters, but it is m+3 for the MLDCL inverters. The output of proposed MLDCL is synthesized as the staircase wave, whose characteristics are nearer to a desired sinusoidal output. The proposed MLDCL inverter topologies can have enhanced performance by implementing the pulse width modulation (PWM) techniques. This paper also presents the most relevant control and modulation methods by a new reference/carrier based PWM scheme for MLDCL inverter and comparing the performance of the proposed scheme with that of the existing cascaded H-bridge multilevel inverter. Finally, the simulation results are included to verify the effectiveness of the both topologies in multilevel inverter configuration and validate the proposed theory. A hardware set up was developed for a singlephase 7-level D.C. Link inverter topology using constant pulses. © 2013 IEEE.
Venkatanarayana M.,KSRMCE |
Jayachandra Prasad T.,RGMCET
ARPN Journal of Engineering and Applied Sciences | Year: 2012
The concept of cepstrum thresholding (CT) is applied to estimate smoothed nonparametric spectrum. The CT method is applied to Mesosphere, Stratosphere and Troposphere (MST) radar data for spectral cleaning. This method is not superior as compared with the conventional Periodogram method. So, to enhance the spectral visibility in Doppler Profile (DP), the CT technique is modified. The modified cepstrum (MC) is developed and implemented, to validate, it is applied to radar data. An adaptive spectral moment's estimation technique is utilized for analyzing the Doppler spectra of the MST radar signals. From the Doppler frequency components, the radial velocities in the direction of the zonal (U), meridional (V), and vertical (W) are estimated. In turn, the wind velocity is estimated from U and V components. The proposed method works well even at higher altitudes and results are compared with the traditional methods such as Peak detection technique and the matched filter. © 2006-2012 Asian Research Publishing Network (ARPN).
Surya Kumari J.,RGMCET |
International Journal of Power Electronics and Drive Systems | Year: 2013
The output power of Photovoltaic (PV) arrays is always changing with weather conditions, i.e., solar irradiation and atmospheric temperature. Therefore, a Maximum Power Point Tracking (MPPT) control to extract maximum power from the PV arrays at real time becomes indispensable in PV generation system. In recent years, a large number of techniques have been proposed for tracking the maximum power point (MPP). MPPT is used in photovoltaic (PV) systems to maximize the photovoltaic array output power, irrespective of the temperature and radiation conditions and of the load electrical characteristics the PV array output power is used to directly control the dc/dc converter, thus reducing the complexity of the system. The resulting system has high-efficiency. This paper presents in details comparison of most popular MPPT algorithms techniques which are Perturb & Observe algorithm (P&O) and Improved Perturb & Observe algorithm (IP&O). In this paper, an improved perturbation and observation method (IP&O) based on adaptive algorithm is proposed, which is automatically adjusts the reference step size and hysteresis bandwidth for power cumparison. The results show that the IP&O increases the total PV output power at an unsettled weather condition compare to traditional perturbation and observation method (P&O). © 2013 Institute of Advanced Engineering and Science. All rights reserved.
Sankar A.S.,P.A. College |
Prasad T.J.,RGMCET |
Giriprasad M.N.,Jawaharlal Nehru Technological University Anantapur
International Conference and Workshop on Emerging Trends in Technology 2011, ICWET 2011 - Conference Proceedings | Year: 2011
Digital Rights Management is a method of controlling access to copyrighted material. Steganography- the art of hiding secrete messages inside other messages, innocuous wrapper, as until recently had been the poor cousin of cryptography, to communicate privately in an open channel. This area of study got widespread popularity after its alleged use by many extremist groups while hatching and executing their plans remotely. Because of this, in the recent past, many law enforcement and government agencies have also shown keen interest in it. There are many other reasons like Digital Rights Management applications (Watermarking and Finger Printing), which acted as catalyst too. This paper proposes a new steganographic encoding scheme which separates the colour channels of the windows bitmap images and then hides messages Randomly using polynomials in the LSB of any colour component of a chosen pixel. The authors, implemented image steganography based on Least Significant Bit Insertion method using Polynomial. The advantages and disadvantages of this method have also been discussed. Copyright © 2011 ACM.