Conference Papers

Permanent URI for this collectionhttps://idr.nitk.ac.in/handle/123456789/28506

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Author: search.filters.author.Acharya, S.

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    Virtual medical board: A distributed Bayesian agent based approach
    (Knowledge Systems Institute Graduate School office@ksi.edu, 2013) Dutta, A.; Acharya, S.; Krishna, A.; Bhattacharya, S.
    Distributed Decision Making has become of increasing importance to get solution of different real life problems. Application of agent and multi agent system in this Distributed Decision Support System is an evolving paradigm. One of such real life problem is medical board formation. But always formation of a medical board with a group of expert physicians may not be always possible due to lack of infrastructure, availability, time etc. In these situations the role of multi agent based distributed decision making can comes into play. In this paper we develop a Virtual Medical Board System in which a number of software agents (expert agents) act as a group of expert physicians with knowledge base(KB), reasoning capability. They coordinate with each other to diagnose a patient. © © 2013 by Knowledge Systems Institute Graduate School.
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    On the improved performance of luby transform codes over selective repeat ARQ in turbulent free space optical links
    (2013) Prakash, G.; Nayak, A.; Kulkarni, M.; Acharya, S.
    Free Space Optical (FSO) links are capable of offering high data transfer rates, secure and low interference links for connectivity as a last mile solution. However, atmospheric turbulence can degrade the performance for distances over 1 km. This degradation is in the form of packet loss and hence drop in the error performance. Error Control Coding (ECC) can be used to mitigate the effects of the atmospheric turbulence. In this paper we prove analytically and verify through simulations that Luby Transform(LT) Codes show an improved performance over Automatic Repeat Request(ARQ) schemes for FSO transmission. FSO systems are limited by the safety limits of the input power to the laser transmitter. A notable contribution in this paper is that we prove that this improvement with LT codes is within Maximum Permissible Exposure (MPE) limit for an FSO link for a BER performance of 10-5. © 2013 IEEE.
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    Characterization of magnetorheological brake utilizing synthesized and commercial fluids
    (Elsevier Ltd, 2019) Acharya, S.; Shyam Saini Tak, R.; Bhanu Singh, S.; Kumar, H.
    Magnetorheological (MR) brakes produce braking torque due to variation in the magnetorheological properties of the MR fluid when external magnetic field is applied. In this study, MR fluids having 70% and 80% weight fractions of iron powder were prepared and MR brake characteristics were tested for prepared MR fluids and a commercial Lord MRF 132 DG fluid. It was found that there was an increase in braking torque with applied current to MR brake at all speeds indicating the MR effect. With increase in weight fraction, there is an increase in braking torque though the reduction in speed is not significant. However, in case of MRF 132 DG fluid, the decrease in rpm is significant especially at higher speeds. Though, the prepared fluids and commercial fluid produce closer braking torque values at higher currents, the increase in braking torque without magnetic field to that with magnetic field at maximum current of MR brake utilizing commercial fluid is very high due to its low viscous torque. Finally, analysis in finite element method magnetics software combined with analytical equations was used to compute torque and compared with experimental results of MR brake utilizing commercial fluid. © 2019 Elsevier Ltd.
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    Optimal design and analyses of t-shaped rotor magnetorheological brake
    (Institute of Physics Publishing helen.craven@iop.org, 2019) Acharya, S.; Saini, R.S.S.; Kumar, H.
    Magnetorheological (MR) brakes, belonging to the class of electromagnetic brakes, have a potential to replace conventional hydraulic brakes owing to reversible, rapidly controllable torque characteristics. In this study, T-shaped rotor MR brake was considered due to their higher braking torque capability and compactness compared to other configurations of brake. Optimal design of the brake was performed considering brake rotor radius, rotor thickness, flange length, casing thickness, coil height and coil width. Magnetostatic analyses were performed for different combinations of parameters of the brake dimensions to compute the magnetic flux density generated in the MR fluid region and the torque ratio and mass were calculated. The optimum dimensions of the brake were determined based on maximization of torque ratio and minimization of mass of the brake using multi-objective Genetic algorithm optimization technique. Further, magnetostatic analyses of the T-rotor brake with optimal dimensions were performed and torque characteristics were compared with those obtained for brake with simple disk rotor. It was concluded that T-rotor brake produces higher braking torque compared to simple disk rotor type MR brake for similar dimensions. © 2019 IOP Publishing Ltd. All rights reserved.
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    Broker-based mechanism for cloud provider selection
    (Inderscience Publishers, 2020) Achar, R.; Santhi Thilagam, P.; Acharya, S.
    Cloud computing has recently emerged as a new computing paradigm for delivering on demand virtualised computing resources over the internet on a pay-as-use basis. Applications hosted in cloud have different requirements which include both low level (resource) requirements and high level (performance) requirements. However, most of the cloud providers satisfy SLAs based on resource requirements rather than providing performance guarantees to applications. This gap creates a need for selecting a more suitable cloud provider who can satisfy performance requirements of applications along with resource requirements. This work aims at proposing a broker-based approach to rank cloud providers based on QoS requirements of customers. It helps the SaaS providers to save cost and complexity in choosing a suitable cloud provider for hosting applications. The experimental results show that proposed approach selects the suitable cloud provider for hosting various types of applications satisfying the needs of different cloud customers. © 2020 Inderscience Enterprises Ltd.