Faculty Publications

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    Performance analysis of secondary storage media through file systems benchmarking
    (Institute of Electrical and Electronics Engineers Inc., 2019) Rakshith, G.; Rozario, R.; Rhevanth, M.; Nikitha, K.M.; Mohan, B.R.
    Efficient performance of a disk I/O operation involves a multitude of factors such as the type of the disk, I/O scheduling, and the type of the file system used. Due to the various types of file systems available, with each having different structure and logic, properties of speed, flexibility, security, size and more, it becomes imperative to have an objective overview of the merits and demerits of each file system according to the needs of the users. In this work, we present a thorough performance evaluation of ext4, NTFS and Btrfs filesystems along with CFQ, NOOP and Deadline I/O schedulers tested on regular hard disk drives and SSDs. © 2019 IEEE.
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    Exploring the Application of Data Envelopment Analysis in the Evaluation of Public Transport Organizations
    (Springer Science and Business Media Deutschland GmbH, 2022) Praveen Kumar, P.P.; George, V.; Mulangi, R.H.
    The work provides details on a study on performing a comparative analysis of productivity and efficiency of selected public transport organizations in India. The data envelopment analysis (DEA) method was used in this study using sub-routines specially developed in the open-source R programming environment used in statistical analyses. The DEA approach is a commonly adopted non-parametric method of analysis for the measurement of efficiency-related characteristics. Based on the availability and consistency of information, selected input and output data on 27 State Road Transport Undertakings (SRTUs) were used in this study. The scores of efficiencies were then computed using an input-oriented DEA model with constant return to scale. Finally, the analysis was used to distinguish between efficient and inefficient SRTUs based on weights assigned to peer units. The results of this study indicate that only 10 out of the 27 SRTUs performed well. It was also found that the performance parameters could be improved by reducing the quantity of input-related parameters in order to maintain the same level of output. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.
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    Static behavior of thermally loaded multilayered Magneto-Electro-Elastic beam
    (Techno-Press, 2017) Mahesh, M.; Kattimani, S.C.
    The present article examines the static response of multilayered magneto-electro-elastic (MEE) beam in thermal environment through finite element (FE) methods. On the basis of the minimum total potential energy principle and the coupled constitutive equations of MEE material, the FE equilibrium equations of cantilever MEE beam is derived. Maxwell's equations are considered to establish the relation between electric field and electric potential; magnetic field and magnetic potential. A simple condensation approach is employed to solve the global FE equilibrium equations. Further, numerical evaluations are made to examine the influence of different in-plane and through-thickness temperature distributions on the multiphysics response of MEE beam. A parametric study is performed to evaluate the effect of stacking sequence and different temperature profiles on the direct and derived quantities of MEE beam. It is believed that the results presented in this article serve as a benchmark for accurate design and analysis of the MEE smart structures in thermal applications. © Copyright 2017 Techno-Press, Ltd.
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    A benchmark study of automated intra-retinal cyst segmentation algorithms using optical coherence tomography B-scans
    (Elsevier Ireland Ltd, 2018) Girish, G.N.; Anima, V.A.; Kothari, A.R.; Sudeep, P.V.; Roychowdhury, S.; Rajan, J.
    (Background and objectives) Retinal cysts are formed by accumulation of fluid in the retina caused by leakages from inflammation or vitreous fractures. Analysis of the retinal cystic spaces holds significance in detection and treatment of several ocular diseases like age-related macular degeneration, diabetic macular edema etc. Thus, segmentation of intra-retinal cysts and quantification of cystic spaces are vital for retinal pathology and severity detection. In the recent years, automated segmentation of intra-retinal cysts using optical coherence tomography B-scans has gained significant importance in the field of retinal image analysis. The objective of this paper is to compare different intra-retinal cyst segmentation algorithms for comparative analysis and benchmarking purposes. (Methods) In this work, we employ a modular approach for standardizing the different segmentation algorithms. Further, we analyze the variations in automated cyst segmentation performances and method scalability across image acquisition systems by using the publicly available cyst segmentation challenge dataset (OPTIMA cyst segmentation challenge). (Results) Several key automated methods are comparatively analyzed using quantitative and qualitative experiments. Our analysis demonstrates the significance of variations in signal-to-noise ratio (SNR), retinal layer morphology and post-processing steps on the automated cyst segmentation processes. (Conclusion) This benchmarking study provides insights towards the scalability of automated processes across vendor-specific imaging modalities to provide guidance for retinal pathology diagnostics and treatment processes. © 2017 Elsevier B.V.
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    DetLogic: A black-box approach for detecting logic vulnerabilities in web applications
    (Academic Press, 2018) Deepa, G.; Santhi Thilagam, P.S.; Praseed, A.; Pais, A.R.
    Web applications are subject to attacks by malicious users owing to the fact that the applications are implemented by software developers with insufficient knowledge about secure programming. The implementation flaws arising due to insecure coding practices allow attackers to exploit the application in order to perform adverse actions leading to undesirable consequences. These flaws can be categorized into injection and logic flaws. As large number of tools and solutions are available for addressing injection flaws, the focus of the attackers is shifting towards exploitation of logic flaws. The logic flaws allow attackers to compromise the application-specific functionality against the expectations of the stakeholders, and hence it is important to identify these flaws in order to avoid exploitation. Therefore, a prototype called DetLogic is developed for detecting different types of logic vulnerabilities such as parameter manipulation, access-control, and workflow bypass vulnerabilities in web applications. DetLogic employs black-box approach, and models the intended behavior of the application as an annotated finite state machine, which is subsequently used for deriving constraints related to input parameters, access-control, and workflows. The derived constraints are violated for simulating attack vectors to identify the vulnerabilities. DetLogic is evaluated against benchmark applications and is found to work effectively. © 2018 Elsevier Ltd
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    An efficient cost optimized scheduling for spot instances in heterogeneous cloud environment
    (Elsevier B.V., 2018) Domanal, S.; Guddeti, G.
    In this paper, we propose a novel efficient and cost optimized scheduling algorithm for a Bag of Tasks (BoT) on Virtual Machines (VMs). Further, in this paper, we use artificial Neural Network to predict the future values of Spot instances and then validate these predicted values with respect to the current (actual) values of Spot instances. On-Demand and Spot are the key instances which are procured by the cloud customers and hence, in this paper, we use these instances for the cost optimization. The key idea of our proposed algorithm is to efficiently utilize the cloud resources (mainly VMs instances, Central Processing Unit (CPU) and Memory) and also to optimize the cost of executing the BoT in the heterogeneous Infrastructure as a Service (IaaS) based cloud environment. Experimental results demonstrate that our proposed scheduling algorithm outperforms state-of-the-art benchmark algorithms (Round Robin, First Come First Serve, Ant Colony Optimization, Genetic Algorithm, etc.) in terms of Quality of Service (QoS) parameters (Reliability, Time and Cost) while executing the BoT in the heterogeneous cloud environment. Since the obtained results are in the form of ordinal, hence we carried out the statistical analysis on both predicted and actual Spot instances using the Spearman's Rho Test. © 2018 Elsevier B.V.
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    Hygrothermal coupling analysis of magneto-electroelastic beams using finite element methods
    (Taylor and Francis Ltd. michael.wagreich@univie.ac.at, 2018) Mahesh, M.; Kattimani, S.C.; Joladarashi, S.
    In this article, the finite element (FE) method has been used to assess the coupled static behavior of hygro-thermo-magneto-electroelastic (HTMEE) beam. Influence of externally applied hygrothermal loads on the direct (displacements, electric and magnetic potentials) and derived quantities (stresses, electric displacement and magnetic flux densities) of HTMEE beam have been studied in detail. The principle of total potential energy and the coupled constitutive equations of HTMEE material are used for the FE formulation. A generalized condensation technique is adopted to solve the global FE equations of motion. Numerical examples are discussed to examine the effect of hygrothermal loads and distinct effect of moisture concentration on the behavior of the beam. Particular emphasis has been placed to analyze the influence of temperature and moisture dependent elastic stiffness coe?cients associated with empirical constants. Considering the independent effect of temperature and moisture on the coupled static responses, the most significant combination of the empirical constants corresponding to temperature dependency and moisture dependency are explored. Extensive computational examples are considered to examine the significant effect of boundary conditions, temperature gradient, moisture concentration gradient and empirical constants on the static behavior of HTMEE beam. It is observed that the static behavior of HTMEE beam is significantly influenced by the hygrothermal loads and empirical constants. The results presented in this article would serve as a benchmark results in design and analysis of HTMEE structures for sensors and actuators applications. © 2018 Taylor & Francis.
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    Exploring the support for high performance applications in the container runtime environment
    (Springer Berlin Heidelberg, 2018) Martin, J.P.; Kandasamy, A.; Chandrasekaran, K.
    Cloud computing is the driving power behind the current technological era. Virtualization is rightly referred to as the backbone of cloud computing. Impacts of virtualization employed in high performance computing (HPC) has been much reviewed by researchers. The overhead in the virtualization layer was one of the reasons which hindered its application in the HPC environment. Recent developments in virtualization, especially the OS container based virtualization provides a solution that employs a lightweight virtualization layer and promises lesser overhead. Containers are advantageous over virtual machines in terms of performance overhead which is a major concern in the case of both data intensive applications and compute intensive applications. Currently, several industries have adopted container technologies such as Docker. While Docker is widely used, it has certain pitfalls such as security issues. The recently introduced CoreOS Rkt container technology overcomes these shortcomings of Docker. There has not been much research on how the Rkt environment is suited for high performance applications. The differences in the stack of the Rkt containers suggest better support for high performance applications. High performance applications consist of CPU-intensive and data-intensive applications. The High Performance Linpack Library and the Graph500 are the commonly used computation intensive and data-intensive benchmark applications respectively. In this work, we explore the feasibility of this inter-operable Rkt container in high performance applications by running the HPL and Graph500 applications and compare its performance with the commonly used container technologies such as LXC and Docker containers. © 2018, The Author(s).
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    Investigation on the eect of using rubber as core material in sandwich composite plate subjected to low-velocity normal and oblique impact loadings
    (Sharif University of Technology, 2019) Mahesh, V.; Joladarashi, S.; Kulkarni, S.M.
    In this article, the structural performance of composite plate under low-velocity impact is studied. Two forms of layup sequence, namely, Jute-Epoxy laminate (JE) and Jute-Epoxy-Rubber sandwich (JE-R-JE), were considered for evaluation. Special emphasis was on evaluating the inuence of normal and oblique loadings. Various dynamic parameters, such as energy, peak load, and deformation, were analysed in detail to study the eect of impact angle on both laminate and sandwich structures. Stress analysis of both laminate and sandwich structures was carried out to discuss the eect of introducing rubber as a core material. The results revealed that using rubber as a core material had a signicant eect on energy absorption. In addition, it was noticed that increasing the angle of impact would yield better performance of the composite plate. The results presented here may serve as benchmark for eective utilization of composite plates in low-velocity impact applications. © 2019 Sharif University of Technology. All rights reserved.
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    An experimental investigation on low-velocity impact response of novel jute/rubber flexible bio-composite
    (Elsevier Ltd, 2019) Mahesh, V.; Joladarashi, S.; Kulkarni, S.M.
    This paper presents an experimental investigation on low velocity impact (LVI) behaviour of flexible biocomposite laminates with different stacking sequence namely jute/rubber/jute (JRJ), jute/rubber/rubber/jute (JRRJ), jute/rubber/jute/rubber/jute (JRJRJ) and subjected to different impact energy levels using a conical shaped impactor. The performances of the proposed flexible composites are evaluated based on their energy absorption, peak force, coefficient of restitution (CoR), energy loss percentage (ELP) and failure behavior. Results indicated that JRJ provides better energy absorption and JRJRJ provides better damage resistance when subjected to LVI. Microscopic analysis revealed that the flexible composites fail mainly due to the tearing mechanism of the matrix as opposed to cracking in case of conventional stiff composites. It was also found that flexible composites are free from delamination. Compared to conventional stiff composites, there is no catastrophic failure observed in the proposed flexible composite. The overall performance evaluation of these proposed flexible composites indicates that these flexible composites can be potential sacrificial materials such as claddings used to protect primary structural components subjected to LVI. The systematic methodology employed in the present study serves as a benchmark for the effective utilization and selection of flexible composites for LVI applications. © 2019 Elsevier Ltd