Journal Articles

Permanent URI for this collectionhttps://idr.nitk.ac.in/handle/123456789/19884

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Author: search.filters.author.Kulkarni, M.

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    Congestion controlling schemes for high-speed data networks: A survey
    (IOS Press Nieuwe Hemweg 6B Amsterdam 1013 BG, 2019) Kharat, P.; Kulkarni, M.
    The data networks are basically designed with the aim of maximum throughput and fair resource allocation by managing available resources. A transport layer plays an important role in throughput and fairness with the help of congestion control algorithms (variants). This survey targets mainly congestion issues in high-speed data networks to improve efficiency at connection or flow level. Transmission Control Protocol (TCP) is a dominating transport layer protocol in the existing network because of its reliable service and deployment in most of the routers. A cause of congestion may be different in wired and wireless network and needs to be handled separately. Packet delay, packet loss and time out (RTO) are not caused by congestion in case of wireless network. This has been taken into account in our consideration. To overcome the dominance of TCP, Google proposed UDP based solution to handle congestion control and reliable service with minimum latency and control overhead. In the literature several methods are proposed to classify transport layer Protocols. In this survey congestion control proposals are classified based on situation handled by the algorithm such as pure congestion, link loss, packet reordering, path optimization etc. and at the end congestion control at flow level has been addressed. © 2019 - IOS Press and the authors.
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    A novel optimal fuzzy system for color image enhancement using bacterial foraging
    (Institute of Electrical and Electronics Engineers Inc., 2009) Hanmandlu, M.; Verma, O.P.; Kumar, N.K.; Kulkarni, M.
    A new approach is presented for the enhancement of color images using the fuzzy logic technique. An objective measure called exposure has been defined to provide an estimate of the underexposed and overexposed regions in the image. This measure serves as the dividing line between the underexposed and overexposed regions of the image. The hue, saturation, and intensity (HSV) color space is employed for the process of enhancement, where the hue component is preserved to keep the original color composition intact. A parametric sigmoid function is used for the enhancement of the luminance component of the underexposed image. A power-law operator is used to improve the overexposed region of the image, and the saturation component of HSV is changed through another power-law operator to recover the lost information in the overexposed region. Objective measures like fuzzy contrast and contrast and visual factors are defined to make the operators adaptive to the image characteristics. Entropy and the visual factors are involved in the objective function, which is optimized using the bacterial foraging algorithm to learn the parameters. Gaussian and triangular membership functions (MFs) are chosen for the underexposed and overexposed regions of the image, respectively. Separate MFs and operators for the two regions make the approach universal to all types of contrast degradations. This approach is applicable to a degraded image of mixed type. On comparison, this approach is found to be better than the genetic algorithm (GA)-based and entropy-based approaches. © 2009 IEEE.
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    Performance comparison of MANET routing protocols
    (2010) Kumar, J.; Kulkarni, M.; Gupta, D.
    A Mobile Ad hoc Network (MANET) is a collection of wireless mobile nodes forming a temporary network without using any existing infrastructure. Since not many MANETs are currently deployed, research in this area is simulation based. We have compared different routing protocols like DSR, DSDV, AODV to study the mobility characteristics of different scenarios in which MANETs may be deployed. Evaluation of the impact of different mobility models on the performance of these routing protocols is carried out, based upon different parameters-throughput, Packet delivery ratio, end to end delay, and offered traffic load. Also, mobility models are compared based on these performance parameters in various routing protocols. © 2010 Praise Worthy Prize S.r.l. - All rights reserved.
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    Energy efficient routing protocols for wireless sensor networks: A survey
    (2011) Shivaprakasha, K.S.; Kulkarni, M.
    Wireless Sensor Networks (WSNs) have become one of the emerging trends of the modern communication systems. They find their applications in various fields like habitat monitoring, home automation, environment monitoring, battle field environment etc. WSNs are different from Mobile Adhoc Networks in the perspective of energy awareness, adaptive communication patterns and the routing algorithms. As the sensor devices are powered by batteries, which cannot be recharged often, the power awareness is one of the major requirements in WSNs. Many energy aware routing protocols have been proposed in the literature. In this survey, an attempt has been made to summarize the various energy aware routing protocols available in the literature and also a comparative analysis of these has been made considering various network parameters like the delay, routing overhead, QoS, type of routing protocol etc. © 2011 Praise Worthy Prize S.r.l. - All rights reserved.
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    Classification of FSO channel models using radial basis function neural networks and their ber performance with Luby transform codes
    (2012) Prakash, G.; Kulkarni, M.; Sripati Acharya, U.; Kalyanpur, M.N.
    Free Space Optical (FSO) communication systems offer a license free and cost effective access performance. FSO links can suffer from data packet corruption and erasure. Error control codes can help to mitigate turbulence induced fading and can improve the error performance of such links. Various statistical models have been proposed to describe the atmospheric turbulence channels. The choice of the appropriate model for varying level of turbulence is dependent on the atmospheric parameters. In this paper we classify the channels using Radial Basis Function Neural Networks to decide the best fit. We then investigate the error performance of FSO channels modeled as Gamma- Gamma and K distribution functions with Luby Transform encoding which are rateless codes. Simulation results are used to compare the performance of different modulation schemes with Luby Transform encoding and also to classify the appropriate distribution function for the channel model. © 2012 by IJAI (CESER Publications).
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    Hybrid scheme for CFO cancellation in OFDM systems
    (Acta Press, 2013) Savitha, H.M.; Kulkarni, M.
    In this paper, we combine maximum likelihood estimation (MLE) technique with improved sinc power (ISP) pulse shaping to cancel inter-carrier interference caused by carrier frequency offset in coded orthogonal frequency division multiplexing (OFDM) systems, thereby achieving an improved bit error rate (BER) performance as compared to the above two schemes. The BER performance of the OFDM system was checked for ISP pulse shaping alone, MLE technique with low pass filtering, and a hybrid scheme of MLE technique with ISP pulse shaping. It has been shown that, at normalized carrier frequency offset of 0.2 and BER of 10-5, the hybrid scheme with convolutional coding could achieve a BER performance improvement of around 1.78 and 4.83 dB, respectively, as compared to MLE technique with low pass filtering and ISP pulse shaping alone. © International Journal of Modelling and Simulation 2013.
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    Improved network survivability using multi-threshold adaptive range clustering (M-TRAC) algorithm for energy balancing in wireless sensor networks
    (2013) Shivaprakasha, K.S.; Kulkarni, M.; Joshi, N.
    Wireless Sensor Networks (WSNs) have become one of the most prominent areas of research in the field of modern communication systems. But unlike IP based routing, WSNs focus on data centric communication. Thus routing is one of the important issues to be considered for a WSN. As sensor networks are generally deployed in hostile environments, batteries cannot be recharged often. Thus energy conservation is one of the important design parameters for WSNs. Many energy aware routing protocols were proposed in the literature. Cluster based algorithms were proved to be better compared to multi-hop routing. In this paper an attempt is made in proposing a novel cluster based energy efficient routing algorithm for WSNs namely the Multi-Threshold Adaptive Range Clustering (M-TRAC) algorithm, which incorporates centralized network management with variable thresholds in order to assure a uniform load distribution amongst nodes, thus improving the network lifetime. © 2013 - IOS Press and the authors. All rights reserved.
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    BER performance enhancement for secure wireless communication systems based on DCSK-MIMO techniques under Rayleigh fading channel
    (2013) Abdulameer, L.F.; Jokhakar, J.D.; Sripati, U.; Kulkarni, M.
    There has been a growing interest in the use of chaotic techniques for enabling secure communication in recent years. This need has been motivated by the emergence of a number of wireless services which require the channel to provide very low bit error rates (BER) along with information security. As more and more information is transacted over wireless media, there has been increasing criminal activity directed against such systems. This paper investigates the feasibility of using chaotic communications over Multiple-Input-Multiple-Output (MIMO) channels. We have studied the performance of differential chaos shift keying (DCSK) with 2×2 Alamouti scheme and 2×1 Alamouti scheme for different chaotic maps over additive white Gaussian noise (AWGN) and channels disturbed by Rayleigh fading. Both the inherently wideband DCSK modulation and the space-time block code (STBC) are techniques that can mitigate the effect of multipath fading. The use of these schemes allows us to enhance security without degrading the BER performance for Rayleigh fading channels. We have employed an exact method to analyze the performances of DCSK communication system over fading channel. Our simulations indicate that the combination of the STC and tent map provides the best BER performance in addition to security when compared to the choice of other maps. Hence, this study shows that the use of these schemes can allow the user to enhance security without degrading the BER performance while communicating over these channels. © 2013 Allerton Press, Inc.
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    Performance analysis of energy efficient modulation and coding schemes for wireless sensor networks
    (2013) Shivaprakasha, K.S.; Kulkarni, M.; Patkar, R.
    Sensor nodes of a typical wireless sensor network (WSN) are battery driven, so energy conservation is a critical factor for node's life time. Thus optimisation of energy consumption is a major objective in the area of WSNs. One such method is asymmetric communication which uses different channel codes and modulation schemes for downlink (base station (BS) to node link) and uplink (node to BS link). In this paper, a performance analysis of different channel code-modulation pair for energy efficient asymmetric communication is carried out followed by the field programmable gate array implementation of channel codes required at the node. The per information bit node energy for the uplink has been calculated for efficient channel code-modulation pair, for three different channels, viz. additive white gaussian noise, Rayleigh flat-fading and log-normal shadowing channels, resulting in reduction in energy consumption at sensor nodes. © 2013 Copyright Taylor and Francis Group, LLC.
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    BER performance enhancement for secure wireless optical communication systems based on chaotic MIMO techniques
    (2014) Abdulameer, L.F.; Jignesh, J.D.; Sripati, U.; Kulkarni, M.
    There has been a growing interest in the use of chaotic techniques for enabling secure communication in recent years. This need has been motivated by the emergence of a number of wireless services which require the channel to provide low bit error rates (BER) along with information security. The aim of such activity is to steal or distort the information being conveyed. Optical Wireless Systems (basically Free Space Optic Systems, FSO) are no exception to this trend. Thus, there is an urgent necessity to design techniques that can secure privileged information against unauthorized eavesdroppers while simultaneously protecting information against channel-induced perturbations and errors. Conventional cryptographic techniques are not designed for protecting information integrity when data is being transferred over a harsh communication medium. Hence, a separate channel coding protocol is often necessary to achieve this goal. Our work indicates that the use of a suitable Chaotic Shift Keying (CSK) map combined with an appropriate Space-Time Code (STC) can allow both requirements to be met. In this paper, we have concentrated on investigating the error rate performance of chaotic-wireless optical communication links operating over atmospheric channel, where the turbulence-induced fading is described by the Gamma-Gamma and log-normal distributions. The main aim of the paper is to assess the feasibility of employing Space-Time Coded chaotic communications over Multiple Input Multiple Output (MIMO) communication channels. Our simulations indicate that the combination of the STC and tent map provides the best BER performance in addition to security when compared to the choice of other maps. © 2013 Springer Science+Business Media Dordrecht.