Faculty Publications
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Item Design, Implementation, and Evaluation of a Low-Cost Visible Light Communication Testbed(Springer Science and Business Media Deutschland GmbH, 2024) Salvi, S.; Geetha, V.The proposed testbed demonstrated and studied the behavior of channels and modulation techniques. Modulation techniques such as On-Off Keying (OOK) and Pulse Duration Modulation (PDM) were implemented on the testbed. Their performance was evaluated based on the distance between the transmitter and receiver, bit rate, and accuracy. A free-space optical communication channel model was also implemented in MATLAB to study the impact of physical characteristics on channel performance. Physical factors such as room dimensions, LED power, and transmitter field of view (FoV) were considered for the simulation. Additionally, the results of the proposed testbed were compared with the standard indoor free-space optical communication channel model implemented in MATLAB. It was observed that the PDM modulation technique consistently provided a 2x improvement in accuracy over OOK modulation for the same distance. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.Item Securing native XML database-driven web applications from XQuery injection vulnerabilities(Elsevier Inc. usjcs@elsevier.com, 2016) Palsetia, N.; Deepa, G.; Ahmed Khan, F.; Santhi Thilagam, P.S.; Pais, A.R.Database-driven web applications today are XML-based as they handle highly diverse information and favor integration of data with other applications. Web applications have become the most popular way to deliver essential services to customers, and the increasing dependency of individuals on web applications makes them an attractive target for adversaries. The adversaries exploit vulnerabilities in the database-driven applications to craft injection attacks which include SQL, XQuery and XPath injections. A large amount of work has been done on identification of SQL injection vulnerabilities resulting in several tools available for the purpose. However, a limited work has been done so far for the identification of XML injection vulnerabilities and the existing tools only identify XML injection vulnerabilities which could lead to a specific type of attack. Hence, this work proposes a black-box fuzzing approach to detect different types of XQuery injection vulnerabilities in web applications driven by native XML databases. A prototype XQueryFuzzer is developed and tested on various vulnerable applications developed with BaseX as the native XML database. An experimental evaluation demonstrates that the prototype is effective against detection of XQuery injection vulnerabilities. Three new categories of attacks specific to XQuery, but not listed in OWASP are identified during testing. © 2016 Elsevier Inc.Item Black-box detection of XQuery injection and parameter tampering vulnerabilities in web applications(Springer Verlag service@springer.de, 2018) Deepa, G.; Santhi Thilagam, P.S.; Ahmed Khan, F.A.; Praseed, A.; Pais, A.R.; Palsetia, N.As web applications become the most popular way to deliver essential services to customers, they also become attractive targets for attackers. The attackers craft injection attacks in database-driven applications through the user-input fields intended for interacting with the applications. Even though precautionary measures such as user-input sanitization is employed at the client side of the application, the attackers can disable the JavaScript at client side and still inject attacks through HTTP parameters. The injected parameters result in attacks due to improper server-side validation of user input. The injected parameters may either contain malicious SQL/XML commands leading to SQL/XPath/XQuery injection or be invalid input that intend to violate the expected behavior of the web application. The former is known as an injection attack, while the latter is called a parameter tampering attack. While SQL injection has been intensively examined by the research community, limited work has been done so far for identifying XML injection and parameter tampering vulnerabilities. Database-driven web applications today rely on XML databases, as XML has gained rapid acceptance due to the fact that it favors integration of data with other applications and handles diverse information. Hence, this work proposes a black-box fuzzing approach to detect XQuery injection and parameter tampering vulnerabilities in web applications driven by native XML databases. A prototype XiParam is developed and tested on vulnerable applications developed with a native XML database, BaseX, as the backend. The experimental evaluation clearly demonstrates that the prototype is effective against detection of both XQuery injection and parameter tampering vulnerabilities. © 2017, Springer-Verlag Berlin Heidelberg.Item Experimental evaluation of diamond burnishing for sustainable manufacturing(Institute of Physics Publishing helen.craven@iop.org, 2018) Sachin, B.; Narendranath, S.; Dupadu, D.Diamond burnishing is one of the most popular surface finishing technique used to achieve an excellent surface finish. The aim of the present study is to investigate the effect of process parameters in diamond burnishing of 17-4 PH stainless steel (PH SS) under cryogenic environment. The requirement of a sustainable environment for various machining processes urged to explore the importance of cryogenic burnishing over other cooling techniques. Surface modification was achieved by the application of liquid nitrogen (LN2) during diamond burnishing. The process parameters considered to reduce the surface roughness (Ra) and increase the surface hardness (H) are burnishing speed, burnishing feed and burnishing force. The diamond burnishing experiments were conducted based on the L9 orthogonal array. The significant parameters and the optimal level of each parameters were determined by using analysis of variance (ANOVA) and main effect plots respectively. Multi-response optimization has been carried out for cryogenic diamond burnishing of 17-4 PH stainless steel by using Taguchi's grey relation analysis (TGRA). From the TGRA, it was observed that at burnishing speed 73 m min-1, burnishing feed 0.048 mm/rev and burnishing force 150 N, improved diamond burnishing performance characteristics were obtained. An improvement in grey relation grade (GRG) was found to be 38.47%. Cryogenic diamond burnishing has led to modifications in the microstructure and also an improvement in the subsurface hardness of the material. © 2018 IOP Publishing Ltd.Item Evaluation of a commercial MR damper for application in semi-active suspension(Springer Nature, 2019) Desai, R.M.; Jamadar, M.E.H.; Kumar, H.; Joladarashi, S.; Rajasekaran, S.C.; Amarnath, G.As the rheology of a magneto-rheological (MR) fluid can be controlled by an externally applied magnetic field, the damping force generated by a MR damper can be controlled by varying the current supplied to an electromagnet inside the damper. This paper presents the experimental evaluation of such a MR damper RD-8040-1 by Lord Corporation, USA, and its application in a semi-active suspension. The experiments were carried out in damping force testing machine. Sinusoidal displacement input was given to the test damper. The set of experiments were repeated for different levels of current (0–1.5 A in steps of 0.25 A) supplied to the MR damper. Plots of force versus displacement for each frequency of excitation and plots of maximum force versus frequency of excitation show that higher values of current lead to elevated values of MR damper forces. This increase in MR damper load with current supplied is studied and analyzed to develop a mathematical model of the MR damper under investigation. The nonlinear softening hysteretic behavior of the MR damper is simulated by using genetic algorithm provided in the optimization toolbox of MATLAB. Calculations on energy dissipation and equivalent damping coefficient of the MR damper show that the same damper can make the suspension system behave as an underdamped system, critically damped system or overdamped system depending on the value of current supplied to it. The application of this MR damper for heavy vehicle driver’s seat suspension is explored with the help of MATLAB simulations. © 2019, Springer Nature Switzerland AG.Item Revisiting design choices in queue disciplines: The PIE case(Elsevier B.V., 2020) Imputato, P.; Avallone, S.; Tahiliani, M.P.; Ramakrishnan, G.Bloated buffers in the Internet add significant queuing delays and have a direct impact on the user perceived latency. There has been an active interest in addressing the problem of rising queue delays by designing easy-to-deploy and efficient Active Queue Management (AQM) algorithms for bottleneck devices. The real deployment of AQM algorithms is a complex task because the efficiency of every algorithm depends on appropriate setting of its parameters. Hence, the design of AQM algorithms is usually entrusted on simulation environments where it is relatively straightforward to evaluate the algorithms with different parameter configurations. Unfortunately, several factors that affect the efficiency of AQM algorithms in real deployment do not manifest during simulations, and therefore, lead to inefficient design of the AQM algorithm. In this paper, we revisit the design considerations of Proportional Integral controller Enhanced (PIE), an algorithm widely considered for network deployment, and extensively evaluate its performance using a Linux based testbed. Our experimental study reveals some performance anomalies in certain circumstances and we prove that they can be attributed to a specific design choice of PIE, namely the use of the estimated departure rate to compute the expected queuing delay. Therefore, we designed an alternative approach based on packet timestamps, implemented it in the Linux kernel and proved its effectiveness through an experimental campaign. © 2020Item An experimental evaluation of the microstructure, mechanical and functional fatigue properties of the boron-doped Cu-Al-Be SMA wires(Elsevier Ltd, 2021) Singh, R.K.; Biswas, P.; Murigendrappa, S.M.; Kattimani, S.An experimental evaluation of the microstructure, mechanical and functional fatigue properties of the Cu-11.70Al-0.45Be doped with Bx (x = 0.05, 0.10, 0.12, and 0.14 wt%) SMA wires has been carried out. The experiments were performed to investigate microstructure, phase/precipitates, and transformation temperatures for both as-cast and wire samples. Furthermore, tensile properties, shape recovery ratio, and functional fatigue evaluation have also been carried out for the wire samples. The investigation shows that the addition of the minor amount of boron and secondary processes involved during the specimen preparation induced excellent grain refinement. The addition of boron decreased transformation temperatures; however, there was not a considerable change observed due to the secondary process. It was observed that tensile properties increases with the boron addition, and complete shape recovery was observed for all the selected alloys. Finally, functional fatigue tests were conducted under constant stress condition and observed that the number of cycles until the failure has increased and more distance recovery was achieved with an increase in boron doping. © 2021Item Effects of fiber addition on performance of high-performance alkali activated slag concrete mixes: An experimental evaluation(Taylor and Francis Ltd., 2022) Manjunath, R.; Narasimhan, M.C.; Kumar, S.There is an ever-increasing awareness on issues connected with emission of high amounts of greenhouse gases from various industries, including that from the concrete construction industry. Performances of alternative binder systems including geopolymers and alkali activated slag concretes are being investigated in this context. There is again a continuous drive to enhance their performances, both when green and on getting hardened and so also, simultaneous efforts are being made to take advantage of all the various fast-track, state-of-art construction technologies, leading to efficient, eco-friendly and economical infrastructure projects. The present authors have developed and evaluated a new set of such alkali activated slag concrete mixes having self-compacting property, along with higher mechanical properties (hereafter referred to as HPAASC mixes) using three industrial by-products, all obtained from iron and steel industry. While these HPAASC mixes have higher compressive strengths (in the range of 70–90 MPa), reasonable split and flexural strengths and are self-compacting, they continue to be brittle just as other high strength concrete mixes. In order to improve their cracking behaviour during failure, either under mechanical loads or on exposure to higher temperatures, addition of increasing amounts of steel fibers in HPAASC mixes is contemplated. Hence in the present study, the attempt is to study the effect of incorporation of fibers (within a small range of 0.4 ? 0.8%) in the new class of high-performance, fibre reinforced. Self-compacting alkali-activated slag concrete mixes–(referred to as HFSASC hereafter). The present study evaluates the properties such as flow ability, compressive strength and flexural toughness performances for these mixes. Results in the present study indicate that, while all the HFSASC mixes exhibit satisfactory passing and flowing abilities specified as per EFNARC standards for self-compacting mixes, they exhibit enhanced toughness characteristics too. © 2020 Informa UK Limited, trading as Taylor & Francis Group.Item Experimental and Statistical Evaluation of the Mechanical Performance of (Jute and Cocopeat) Plant and (Silk) Animal-based Hybrid Fibers Reinforced with Epoxy Polymers(Taylor and Francis Ltd., 2022) Lokesh, L.K.; Shanmugam, B.K.; Paavan Kumar, T.; Hanumanthappa, H.; Thimmegowda, M.; Mayya, S.D.; Yashaswini Srivatsav, S.K.; Kavitha Kumar, A.B.In India, research on the development of new composite materials is extensively increased. In the present study, composites are developed with the renewable materials of plant and animal-based natural fibers. The present study will lead to the experimental and statistical investigation of the composite produced with a combination of plant-based natural fibers, i.e., jute and coco peat powder with the animal-based natural fibers, i.e., silk. In the present study, jute and silk were utilized as reinforcement material, cocopeat powder as a filler material (5%), and epoxy resin as matrix material (35%). The composites were prepared with the varying composition of reinforcement material, and also the filler and matrix material were kept constant. Furthermore, mechanical properties such as tensile, flexural, and impact tests were performed on the developed composites. Further, a comparative study was drawn on the mechanical test results of tensile and flexural strength of the composite using power and polynomial regression model. The regression coefficient (R2) was used to study the correlation between the experimental and predicted values. The results showed that the polynomial regression is the best suitable mathematical model than the power regression model for predicting the composites’ tensile and flexural test performance. © 2022 Taylor & Francis.