Browsing by Author "Kumar, M.S."
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Item Coding In WDM Systems to Counter Impacts of SRS and Channel Beat Noise(International Academy of Microwave and Optical Technology (IAMOT), 2006) Mruthyunjaya, H.S.; Umesh, G.; Kumar, M.S.Depletion in power due to Stimulated Raman Scattering (SRS) impairs Wavelength Division Multiplexed (WDM) system performance. This is countered usually by placing optical amplifiers to maintain required Bit Error Rate (BER) performance. Also, impact of crosstalk in N x N WDM systems causes high noise power. In this paper we propose the use of block codes for forward error correction as a possible method for improving the performance of WDM systems in the presence of SRS and crosstalk. Our results show that with 200 users and with error control coding, the detector can effectively receive the required power and attain the desired BER performance in SRS limited WDM systems. Our results also show that the multiplexer crosstalk effectively comes down to -44 dB from -34 dB. © 2006 ISRAMT. All Rights Reserved.Item Estimating anisotropic heterogeneous hydraulic conductivity and dispersivity in a layered coastal aquifer of Dakshina Kannada District, Karnataka(Elsevier B.V., 2018) Priyanka, B.N.; Kumar, M.S.; Mahesha, M.The solution for the inverse problem of seawater intrusion at an aquifer scale has not been studied as extensively as forward modeling, because of the conceptual and computational difficulties involved. A three-dimensional variable-density conceptual phreatic model is developed by constraining with real-field data such as layering, aquifer bottom topography and appropriate initial conditions. The initial aquifer parameters are layered heterogeneous and spatially homogeneous that are based on discrete field measurements. The developed conceptual model shows poor correlation with observed state variables (hydraulic head and solute concentration), signifying the importance of spatial heterogeneity in hydraulic conductivity and dispersivity of all the layers. The conceptual model is inverted to estimate the anisotropic spatially varying hydraulic conductivity and the longitudinal dispersivity at the pilot points by minimizing the least square error of state variables across the observation wells. The inverse calibrated model is validated for the hydraulic head at validation wells and the solute concentration is validated with equivalent solute concentration derived from the electrical resistivity, which shows good results against the field measurements. The verification of estimated anisotropic hydraulic conductivity with the electrical resistivity tomography image shows good agreement. This investigation gives an insight about constraining the highly parameterized inverse model with real-field data to estimate spatially varying aquifer parameters for an effective simulation of the seawater intrusion in a layered coastal aquifer. © 2018 Elsevier B.V.Item Iterative or Turbo decoding of parallel concatenated binary error control codes in Binary Phase Shift Keyed (BPSK) Communication System corrupted by both Additive White Gaussian Noise (AWGN) and oscillator phase noise is discussed. As an example of application of the discussed theory, iterative decoding technique of Parallel Concatenated block Codes (PCBC) is applied to a coherent Optical Code Division Multiple Access (OCDMA) network in the presence of Multiple Access Interference (MAI), detector shot noise and laser phase noise. Remarkable improvement in performance resulting from the use of turbo decoding in the OCDMA network is also discussed.(Medknow Publications, Performance of iteratively decoded parallel concatenated error control codes in phase noise corrupted BPSK systems) Kumar, M.S.; Bhat, K.N.H.; Umesh, G.2004Item Long haul, repeaterless, coherent optical multichannel communication systems employing hybrid multiplexing schemes wherein Wavelength Division Multiplexing (WDM) and Optical Code Division Multiplexing (OCDM) are combined is analyzed in the presence of performance limiting factors such as Inter Channel Interference (ICI), Stimulated Raman Scattering (SRS) and detector shot noise. Error control coding techniques in the form of rate 1/2 convolutional codes are employed in the system to counter these performance limiting factors. It is seen that the use of error control coding technique can enhance the system performance to such an extent that a Bit Error Rate (BER) performance of less than 10-8 is achievable without crossing the SRS power threshold for as many as 1000 to 1200 channels. Advantages of the hybrid multiplexed system over systems relying solely on WDM or OCDM are also discussed along with the advantages of using error control coding compared to optical amplification in countering the performance degrading factors.(Fachverlag Schiele und Sohn GmbH, Coding to enhance performance of hybrid multiplexed coherent optical communication systems in the presence of ICI and SRS) Kumar, M.S.; Bhat, K.N.H.; Umesh, G.2003Item Monitoring land use and land cover changes in coastal karnataka(Springer Science and Business Media Deutschland GmbH, 2021) Kumar, M.S.; Venkatesh, V.; Gowthami, S.B.; Anjita, N.A.; Nayana, N.; Regi, L.; Dwarakish, G.S.The dynamics of land use/land cover can be studied by using digital change detection techniques which are highly significant for the evaluation and development of management strategies in a region. The environmental and hydrological processes prevailing in the area can be interpreted only by analyzing the alterations in the past and present land use and land cover classes. In view of this, the present study is executed to analyze the typical land use change in the coastal region over the three decades by analyzing historical and current land use/land cover (LU/LC) datasets. Landsat 5 and Landsat 8 satellite datasets were considered for change detection analysis using unsupervised classification method. K-means algorithm, a widely used unsupervised classification technique, was adopted in this study to classify coastal region of Karnataka for the years 1990 and 2019. The level-II classification was performed on LU/LC raster datasets (Landsat 5 and 8) which segregated the entire study area into ten classes, namely agricultural land, barren land, built-up area, water, forest, fallow or cultivated land, scrub forest, sandy area, swampy forest and wetlands. This study encapsulated that about 40% of the study area was occupied by water body followed by forestry with a percentage of around 30%. Major changes were observed in the barren land and scrub forest between 1990 and 2019, where the barren land was replaced by scrub forest in 2019. The accuracy assessment is performed to analyze the efficiency of the algorithm and the precision of the classified image which showed an accuracy of 81% in 1990 and 84% in 2019 demonstrating the ability of an algorithm to classify reliably. © Springer Nature Singapore Pte Ltd 2021.Item Reliable and robust transmission and storage of medical images with patient information(2004) Nayak, J.; Subbanna, Bhat, P.; Kumar, M.S.; Rajendra, Acharya, U.A new method for compact storage and transmission of medical images with concealed patient information in noisy environment is evinced. Digital Watermarking is the technique adapted here for interleaving patient information with medical images. The patient information, which comprises of text data and signal graph, is encrypted to prevent unauthorized access of data. The latest encryption algorithm (Rijndael) is used for encrypting the text information. Signal graphs (ECG, EEG EMG etc.) are compressed using DPCM technique. To enhance the robustness of the embedded information, the patient information is coded by Error Correcting Codes (ECC) such as (7,4) Hamming, Bose-Chaudhuri-Hocquenghem (BCH) and Reed Solomon (RS) codes. The noisy scenario is simulated by adding salt and pepper (S&P) noise to the embedded image. For different Signal to Noise Ratio (SNR) of the image, Bit Error Rate (BER) and Number of Character Altered (NOCA) for text data and percentage distortion (PDIST) for the signal graph are evaluated. The performance comparison based on the above parameters is conducted for three types of ECC. It is elicited that coded systems can perform better than the uncoded systems. � 2004 IEEE.Item Reliable and robust transmission and storage of medical images with patient information(2004) Nayak, J.; Subbanna Bhat, P.; Kumar, M.S.; Acharya, A.U.A new method for compact storage and transmission of medical images with concealed patient information in noisy environment is evinced. Digital Watermarking is the technique adapted here for interleaving patient information with medical images. The patient information, which comprises of text data and signal graph, is encrypted to prevent unauthorized access of data. The latest encryption algorithm (Rijndael) is used for encrypting the text information. Signal graphs (ECG, EEG EMG etc.) are compressed using DPCM technique. To enhance the robustness of the embedded information, the patient information is coded by Error Correcting Codes (ECC) such as (7,4) Hamming, Bose-Chaudhuri-Hocquenghem (BCH) and Reed Solomon (RS) codes. The noisy scenario is simulated by adding salt and pepper (S&P) noise to the embedded image. For different Signal to Noise Ratio (SNR) of the image, Bit Error Rate (BER) and Number of Character Altered (NOCA) for text data and percentage distortion (PDIST) for the signal graph are evaluated. The performance comparison based on the above parameters is conducted for three types of ECC. It is elicited that coded systems can perform better than the uncoded systems. © 2004 IEEE.Item Reliable transmission and storage of medical images with patient information using error control codes(2004) Nayak, J.; Bhat, P.S.; Kumar, M.S.; Rajendra, Acharya, U.A new method for compact storage and transmission of medical Images with concealed patient Information in noisy environment if evinced. Digital Watermarking is the technique adapted here for interleaving patient Information with medical images. The patient information, which comprises of text data and signal graph, is encrypted to prevent unauthorized access of data. The latest encryption algorithm (Rijndael) is used for encrypting the text information. Signal graphs (ECG, EEG EMG etc.) are compressed using DPCM technique. To enhance the robustness of the embedded information, the patient Information Is coded by Error Correcting Codes (ECC) Reed Solomon (RS) codes. The noisy scenario Is simulated by adding salt and pepper (S&P) noise to the embedded Image. For different Signal to Noise Ratio (SNR) of the image, Bit Error Rate (BER) and Number of Character Altered (NOCA) for text data and percentage distortion (PDIST) for the signal graph is evaluated. It Is elicited that coded systems can perform better than the uncoded systems. � 2004 IEEE.Item Reliable transmission and storage of medical images with patient information using error control codes(2004) Nayak, J.; Subbanna Bhat, P.; Kumar, M.S.; Acharya, A.U.A new method for compact storage and transmission of medical Images with concealed patient Information in noisy environment if evinced. Digital Watermarking is the technique adapted here for interleaving patient Information with medical images. The patient information, which comprises of text data and signal graph, is encrypted to prevent unauthorized access of data. The latest encryption algorithm (Rijndael) is used for encrypting the text information. Signal graphs (ECG, EEG EMG etc.) are compressed using DPCM technique. To enhance the robustness of the embedded information, the patient Information Is coded by Error Correcting Codes (ECC) Reed Solomon (RS) codes. The noisy scenario Is simulated by adding salt and pepper (S&P) noise to the embedded Image. For different Signal to Noise Ratio (SNR) of the image, Bit Error Rate (BER) and Number of Character Altered (NOCA) for text data and percentage distortion (PDIST) for the signal graph is evaluated. It Is elicited that coded systems can perform better than the uncoded systems. © 2004 IEEE.Item Stability analysis of a novel PMBLDC motor drive for electric scooter application(2016) Kumar, M.S.; Udyakumar, R.Y.A state of art design and stability analysis of high power density and high efficiency Permanent Magnet Brushless DC (PMBLDC) Motor drive suitable for light electric vehicle application is presented in this paper. The motor used is poly-phase, multi-pole, rectangular wave Permanent Magnet motor with outer rotor configuration. The spokes of the wheel is directly fitted in to the outer rotor of this proposed motor. In comparison to the conventional PMBLDC motor this motor has special features namely, reduction in volume and weight, saving in copper and elimination of cogging torque. The motor operates at high starting torque and high cruising speed. Hence the proposed PMBLDC drive will have high power density, high efficiency and fast dynamic performance which will be best suited for gearless electric vehicle application. The design and stability analysis are carried out on 3-phase, 8pole PMBLDC motor drive. Simulation results are obtained with Matlab. The objective of the light electric vehicle is to provide high efficiency controllability and safety with wide speed range. The simulation results show that the developed PMBLDC motor model with modular approach and enhanced efficiency is best suited for light electric vehicles. � 2015 IEEE.Item Stability analysis of a novel PMBLDC motor drive for electric scooter application(Institute of Electrical and Electronics Engineers Inc., 2016) Kumar, M.S.; Udyakumar, R.Y.A state of art design and stability analysis of high power density and high efficiency Permanent Magnet Brushless DC (PMBLDC) Motor drive suitable for light electric vehicle application is presented in this paper. The motor used is poly-phase, multi-pole, rectangular wave Permanent Magnet motor with outer rotor configuration. The spokes of the wheel is directly fitted in to the outer rotor of this proposed motor. In comparison to the conventional PMBLDC motor this motor has special features namely, reduction in volume and weight, saving in copper and elimination of cogging torque. The motor operates at high starting torque and high cruising speed. Hence the proposed PMBLDC drive will have high power density, high efficiency and fast dynamic performance which will be best suited for gearless electric vehicle application. The design and stability analysis are carried out on 3-phase, 8pole PMBLDC motor drive. Simulation results are obtained with Matlab. The objective of the light electric vehicle is to provide high efficiency controllability and safety with wide speed range. The simulation results show that the developed PMBLDC motor model with modular approach and enhanced efficiency is best suited for light electric vehicles. © 2015 IEEE.Item The theoretical model for realization of an all-fiber, polarization independent Group Velocity Dispersion (GVD) compensating module with transfer function given by Chebyshev polynomials of the second kind is proposed and investigated. The proposed realization of the GVD compensating module comprises of Mach-Zender interferometers formed by single mode fiber optic directional couplers. The realization of GVD compensating modules using single mode fiber optic couplers as proposed in this paper is superior to an earlier realization of a similar GVD compensating module, which used bulk optic components such as TiO2 birefringent crystals, polarizers and ?/4 plates. © by Fachverlag Schiele & Schön 2005.(An all-fiber polarization independent GVD compensating module) Kumar, M.S.; Bhat, K.N.H.; Umesh, G.2005Item Transmission and storage of medical images with patient information(Elsevier Ltd, 2003) Acharya, A.U.; Subbanna Bhat, S.; Kumar, M.S.; Min, L.C.Digital watermarking is a technique of hiding specific identification data for copyright authentication. This technique is adapted here for interleaving patient information with medical images, to reduce storage and transmission overheads. The text data is encrypted before interleaving with images to ensure greater security. The graphical signals are interleaved with the image. Two types of error control-coding techniques are proposed to enhance reliability of transmission and storage of medical images interleaved with patient information. Transmission and storage scenarios are simulated with and without error control coding and a qualitative as well as quantitative interpretation of the reliability enhancement resulting from the use of various commonly used error control codes such as repetitive, and (7,4) Hamming code is provided. © 2003 Elsevier Science Ltd. All rights reserved.Item Transmission and storage of medical images with patient information(Elsevier Ltd, 2003) Acharya, A.U.; Subbanna Bhat, S.; Kumar, M.S.; Min, L.C.Digital watermarking is a technique of hiding specific identification data for copyright authentication. This technique is adapted here for interleaving patient information with medical images, to reduce storage and transmission overheads. The text data is encrypted before interleaving with images to ensure greater security. The graphical signals are interleaved with the image. Two types of error control-coding techniques are proposed to enhance reliability of transmission and storage of medical images interleaved with patient information. Transmission and storage scenarios are simulated with and without error control coding and a qualitative as well as quantitative interpretation of the reliability enhancement resulting from the use of various commonly used error control codes such as repetitive, and (7,4) Hamming code is provided. © 2003 Elsevier Science Ltd. All rights reserved.