Faculty Publications
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Publications by NITK Faculty
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Item A simple and efficient mechanism to detect and avoid wormhole attacks in mobile ad hoc networks(2012) Raju, V.K.; Kumar, K.V.Mobile ad hoc networks are vulnerable to many kinds of attacks since they have unique characteristics like limited bandwidth, limited battery power and dynamic network topology. Among the various attacks possible in mobile ad hoc networks wormhole attack is one which is treated as a very severe attack. In this attack a malicious node records packets at one location in the network and tunnels them to another malicious node which is present in the other end of the network. In this paper, we have proposed an algorithm which detects and avoids the wormhole attack in the routing phase itself. Our mechanism is based on the total round trip time (RTT) of the established route and the average round trip times of the sender one hop neighbors, which is considered as maximum one hop round trip time. Our solution works for both mobile ad hoc networks and wireless ad hoc networks. © 2012 IEEE.Item Split personality malware detection and defeating in popular virtual machines(2012) Kumar, A.V.; Vishnani, K.; Kumar, K.V.Virtual Machines have gained immense popularity amongst the Security Researchers and Malware Analysts due to their pertinent design to analyze malware without risking permanent infection to the actual system carrying out the tests. This is because during analysis, even if a malware infects and destabilizes the guest OS, the analyst can simply load in a fresh image thus avoiding any damage to the actual machine. However, the cat and mouse game between the Black Hat and the White Hat Hackers is a well established fact. Hence, the malware writers have once again raised their stakes by creating a new kind of malware which can detect the presence of virtual machines. Once it detects that it is running on a virtual machine, it either terminates execution immediately or simply hides its malicious intent and continues to execute in a benign manner thus evading its own detection. This category of malware has been termed as Split Personality malware or Analysis Aware malware in the Information Security jargon. This paper aims at defeating the split personality malware in popular virtual machine environment. This work includes first the study of various virtual machine detection techniques and then development of a method to thwart these techniques from successfully detecting the virtual machines-VirtualBox, VirtualPC and VMware. Copyright © 2012 ACM.Item Modified RED algorithm to improve the performance of web traffic(2013) Dadhania, M.K.; Kumar, K.V.Reducing the delay of web traffic has been an important issue in Internet works. However, it is difficult to reduce delay while improving throughput. This is because, in order to reduce delay queue size should be less but to improve throughput queue size should be more. In our modification, web traffic and ECN marked packets are dropped only when high congestion occurs at router. We propose a solution to improve response time as well as the number of packets transmitted of web traffic without affecting throughput of bottleneck link. We applied this solution to RED algorithm and tested the performance and efficiency of modified RED algorithm as compared to the original RED algorithm. © 2013 IEEE.Item A Comparative Study of Different Capacitor Voltage Control Design Strategies for Z-Source Inverter(Taylor and Francis Ltd., 2022) Kumar, K.V.; Reddivari, R.; Jena, D.The Z-source inverter (ZSI) is a prominent single-stage power conversion topology compared to traditional voltage source inverter (VSI)/ current source inverter (CSI). It adds the additional buck–boost capability to input voltage with improved reliability. However, the non-minimum phase (NMP) behavior is the major disadvantage of ZSI due to the existence of the right half plane (RHP) zero in the converter transfer functions. The existences of RHP zero destabilize the wideband feedback loops, which imply high gain instability and introduce the constraints on controller design. This paper presents different types of controllers and its design to maintain the required capacitor voltage with better transient response for non-minimum phase ZSI. Different tuning algorithms have been considered for both proportional–integral (PI), and integral–proportional (IP) control schemes. Also, the unified control algorithm has been implemented with both simple boost pulse width modulation (SBPWM) and a modified space vector pulse width modulation (MSVPWM) schemes to obtain the required capacitor voltage. The converter performance is comprehensively analyzed for different controllers and observations are tabulated. The complete analysis has been carried out using the MATLAB/Simulink environment for the proposed models. © 2022 IETE.Item IMU-based segmental root mean square analysis of gait in individuals with cerebellar ataxia: a pilot cross-sectional study(Nature Research, 2025) Mendonca, J.; Joshua, A.M.; Shetty, S.; Chemmangat, K.; Krishnan, S.; Kumar, K.V.; Misri, Z.; Pai, R.; Pai, S.Cerebellar ataxia (CA) affects limb movement, balance, and gait. Subjective rating scales like Scale for the Assessment and Rating of Ataxia (SARA) may underestimate gait severity. Inertial measurement units (IMUs) offer an objective gait analysis. Impaired trunk control might compromise gait performance and stability in individuals with ataxia. This study quantified trunk kinematics and gait parameters using Root Mean Square (RMS) values, comparing CA to healthy individuals. Ten CA cases and twenty healthy controls were recruited. Six IMU sensors positioned at anatomical landmarks recorded data via two ESP32 microcontrollers using Wi-Fi. Participants walked a 10-meter path at a self-selected pace. RMS mean linear and angular velocity and angular deviation were calculated. Individuals with CA showed decreased mediolateral linear acceleration at the left shoulder (p = 0.001) and an increased vertical linear acceleration at the right ankle (p = 0.015), left shoulder (p = 0.028), and back (p = 0.019). Total angular velocity was lower at the right shoulder (p = 0.017), left shoulder (p = 0.005), back (p = 0.002), and both ankles (right: p = 0.001; left: p = 0.001). The correlation between IMU-derived features and SARA-gait score in the CA group was not statistically significant (all p > 0.05), except for the right shoulder’s mediolateral angular velocity (p = 0.046). Both ankle segments’ angular deviations (right: p = 0.001; left: p = 0.006) were reduced. The CA group revealed reduced RMS linear and angular velocities. IMU-based trunk and gait analysis provides a more objective method that would help in planning targeted rehabilitation treatments. Trial registration: The study was approved by the Institutional Ethics Committee (IEC), Kasturba Medical College, Mangalore, Manipal Academy of Higher Education (IEC KMC MLR 12/2023/483) on 21st December 2023 and the Clinical Trial Registration (CTRI/2024/07/070614) on July 15th, 2024. © The Author(s) 2025.