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Padmanabhan V.,Thejus Engineering College | Beena V.,Government Engineering College at Thrissur
2012 International Conference on Power, Signals, Controls and Computation, EPSCICON 2012 | Year: 2012

To meet the future energy requirement and to give quality and pollution free supply to growing and environment conscious population, the present world is giving special attention to natural, clean and renewable energy sources. Due to growing demand for electrical energy and environmental issues such as pollution and global warming effect, solar energy is considered among one of the best options for generating clean energy. In this paper a fuzzy logic controller (FLC) is used as an intelligent method for Maximum Power Point Tracking (MPPT) for a Photo Voltaic (PV) system. Fuzzy logic has been used for tracking the Maximum Power Point of PV systems because it has the advantages of being robust, relatively simple to design and does not require the knowledge of an exact model © 2012 IEEE.


John S.P.,Thejus Engineering College | Samuel P.,Cochin University of Science and Technology
Information Security Journal | Year: 2011

In cluster-based key management techniques, the details of the mobile nodes are gathered always before joining or starting the clustering process,which produces congestion and additional overhead. In this paper, to reduce overhead and congestion of a cluster head, we propose a predictive clustering technique for effective key management. The predictive technique predicts the node movement and proactively sends information in cases of cluster movement. The combined metric for prediction is estimated based on route expiration time and node velocity. In key management technique, each cluster head retains the public key of its member nodes only and act as a router when dealing with nodes of other cluster members. Using this technique, the overhead on centralized key management schemes is reduced. Moreover, the need of each node storing all public keys is diminished, thus minimizing the storage overhead on each node. By simulation results, we show that the proposed scheme is more efficient for minimizing overhead and congestion. © 2011 Copyright Taylor and Francis Group, LLC.


John S.P.,Thejus Engineering College | Samuel P.,Cochin University of Science and Technology
International Journal of Business Data Communications and Networking | Year: 2014

Owing to the wireless and dynamic nature, MANETs are susceptible to security attacks from malicious nodes. Key management, certificate exchange and certificate revocation mechanisms play a vital role in securing the network from attacks. When the certificate of a malicious node is revoked, it is denied from all activities and isolated from the network. This paper surveys various existing mechanisms in key management and certificate exchange. Key management methods are broadly classified into two types namely, contributory and distributive methods. Here, certificate distribution and exchange techniques are classified as trust-based and non-trust based methods. Certificate revocation techniques are classified as voting-based, cluster-based and trust-based schemes. The merits and demerits of each mechanism along with the performance are analyzed. Finally, a comparison table is designed to compare the existing mechanisms in an effective manner. © 2014, IGI Global.


John S.P.,Thejus Engineering College | Samuel P.,Cochin University of Science and Technology
ICINA 2010 - 2010 International Conference on Information, Networking and Automation, Proceedings | Year: 2010

In MANET, when a node is compromised it tends to reveal the other node's key information and corrupts the whole network. The scalable method of cryptographic key management (SMOCK) proposes a method to deal with such node compromise attacks. But it has certain main drawbacks such as over dependent on centralized server and increase in key-pair when node increases. To deal with these drawbacks, we present an enhanced hierarchical key management scheme using a stable and power efficient cluster management technique. Each cluster head retains the public key of its member nodes only and act as a router when dealing with nodes of other cluster members. Using this technique, the overhead on centralized server is reduced. Moreover, the need of each node storing all public keys are diminished thus minimizing the storage overhead on each node. By Simulation results, we show that our proposed scheme achieves better delivery ratio and resilience with reduced delay and overhead. © 2010 IEEE.


John S.P.,Thejus Engineering College | Samuel P.,Cochin University of Science and Technology
Ain Shams Engineering Journal | Year: 2014

In MANET, security is more challenging due to problems related to key exchange. It is necessary to secure the exchanges in MANETs for assuring the development of services in the network. The self-organized MANET is visualized as a key communication technology enabler for application such as network centric warfare, disaster relief operations, emergency situations, and intelligent transportation systems. In this paper, we propose a self-organized key management technique coupled with trusted certificate exchange for mobile ad hoc networks. The proposed architecture consists of one coordinator node, servers and normal mobile nodes. The coordinator acts as a mediator for transmitting the message among the servers and mobile nodes. Each node generates its own public/private key pairs using server-signed public keying technique. Then multi-path certificate exchange technique is employed where public key of the nodes is certified by different nodes. Those nodes that issued the certificates are validated using the Eigen Vector Reputation Centrality. By simulation results, we show that the proposed approach improves security. © 2014 Production and hosting by Elsevier B.V. on behalf of Ain Shams University. This is an open access article under the CC BY-NC-ND license.


John S.P.,Thejus Engineering College | Samuel P.,Cochin University of Science and Technology
International Review on Computers and Software | Year: 2013

In Mobile Ad Hoc Networks (MANET), the certificate exchange technique helps the nodes to authenticate themselves with the members in the network before they get joined and starts accessing the network resources. The paths we use for certificate exchange should be secured and reliable. In MANET, the existing routing protocols do not provide security so that an active attacker can alter the control packets which can compromise the routing protocol's integrity. Also the replay attack occurs when an attacking node listens to packets and then re-broadcast the same packets. In order to overcome these issues, in this paper, we propose a secure multipath routing protocol for certificate exchange which is based on optimized link state routing (OLSR) in MANET. Our proposed approach employs the neighborhood authentication technique that provides integrity. In this technique, the control message such as HELLO and topology control messages are used to construct the routing along with list of shareholder nodes. These control messages assist in attaining and distributing topology information and the generated signatures validates the integrity. Also in order to prevent the replay attacks, the timestamp exchange mechanism is employed. By simulation results we show that the proposed approach offers more security in MANET. © 2013 Praise Worthy Prize S.r.l. - All rights reserved.


Sreedevi A.,Thejus Engineering College | Priyanka K.P.,Nanoscience Research Center | Babitha K.K.,Nanoscience Research Center | Aloysius Sabu N.,Nanoscience Research Center | And 2 more authors.
Indian Journal of Physics | Year: 2015

Silver tungstate (α-Ag2WO4) nanoparticles were synthesized by chemical precipitation method. Thermodynamic stability of the α-Ag2WO4 nanoparticles was studied by thermogravimetric and differential thermal analysis. These nanoparticles were structurally characterized by X-ray diffraction, Fourier transform infrared spectroscopy and Raman spectroscopy. The structure and morphology of these nanoparticles were studied by scanning electron microscopy and high-resolution transmission electron microscopy. The composition of nanoparticles near and at the surface was estimated by using energy-dispersive X-ray analysis. The optical properties of these nanoparticles were investigated by UV–Visible as well as photoluminescence spectroscopy. The effects of calcination temperature on the geometric parameters and optical properties of α-Ag2WO4 nanoparticle samples was also investigated. © 2015, Indian Association for the Cultivation of Science.


Babitha K.K.,Nanoscience Research Center | Sreedevi A.,Thejus Engineering College | Priyanka K.P.,Nanoscience Research Center | Sabu B.,University of Mumbai | Varghese T.,Nanoscience Research Center
Indian Journal of Pure and Applied Physics | Year: 2015

Cerium oxide (ceria) nanoparticles were synthesized using cerium nitrate and ammonium carbonate as precursors. As-synthesized CeO2 powders were calcined between 400-850°C for 2 h. The samples were characterized by thermogravimetric analysis, X-ray powder diffraction, transmission electron microscopy, Fourier transform infrared, UV-Visible, photoluminescence and Raman spectroscopies. The FTIR spectrum exhibits strong broad band below 600 cm-1 which is due to Ce-O stretching mode to confirm the formation of pure CeO2. It is shown that average particle size increases as calcination temperature is increased and the absorption is red shifted. PL studies observed that emission band is blue shifted and intensity of emission peaks decreases with increase in calcination temperature. Raman spectrum is characterized by the presence of a very strong band near 464 cm-1. The desired structural and optical properties of CeO2 nanoparticles make it as a promising material for photocatalytic and optoelectronic applications.


Krishnan B.,College of Engineering, Trivandrum | Vasantha P.A.,Thejus Engineering College
Journal of Computing in Civil Engineering | Year: 2015

A fuzzy logic-based modeling approach using the universal soil-loss equation (USLE) along with selection and application of the appropriate coir geotextile (CG) in soil erosion control was attempted in this study. The fuzzy logic model was developed to address issues of soil erosion risk with constant rainfall intensity. Two simple and efficient fuzzy logic soil erosion models were developed, of which one was for predicting soil erosion intensity (fuzzy-soil erosion model, or F-SEM) and the other was for selecting an appropriate CG type for soil erosion control based on types of soil in various combinations of slope angle and length, crop cover, rainfall intensity, and so forth (fuzzy-CG model, or F-CGM). These two models were developed in such a way that the input data requirement was the minimum for model execution. The considered input parameters were the main primary governing factors that influence soil erosion intensity in the USLE platform. F-SEM and F-CGM was compared with actual field data and found to be very closely matching. F-SEM predicts the erosion intensity of an area, and F-CGM can be used in the selection of CGs for erosion control application. © 2014 American Society of Civil Engineers.


John S.P.,Thejus Engineering College
International Conference on Intelligent Systems Design and Applications, ISDA | Year: 2012

Mobile ad hoc networks play a vital role in the military tactical and other security-sensitive operations. Due to unreliable wireless media, host mobility and lack of infrastructure, providing secure communications is an immense challenge in this unique network environment. Specifically Key Distribution cryptographic techniques are typically applied in order to provide secure communications in wired and wireless networks. In Distributed Key Management Model Surplus memory usage and amplified Process Time were sufficiently needed. In order to address this current issue a novel one hop virtual group Shared Based Key Management system called is presented. It minimizes the number of key usage, memory usage and improves throughput; simultaneously acquiring increasing rate in Quality of Service. Experiment is made for the above supposed strategies wherein 10% to 20% rise is obtained in our proposed strategy. © 2012 IEEE.

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