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Senthilkumar S.,Cr Engineering College
Automatic Control and Computer Sciences | Year: 2016

Cognitive Radio Network (CRN) is an intelligent wireless communication system that adapts itself to variations in the incoming radio frequency stimuli by modifying the operating parameters. Using the spectrum sensing techniques, the idle channels are detected, and allocated to the Secondary Users (SUs). The existing cooperative spectrum sensing techniques such as centralized sensing technique, Distributed sensing technique, and External sensing technique exploit efficient prediction models for allocating the frequency spectrum to SUs. For an optimal assignment of the channel using channel parameters, the channel estimation techniques such as pilot-assisted channel estimation, blind and semi blind estimation technique, and decision directed channel estimation technique are analyzed. The flexible nature of the CRN introduces various security attacks such as Primary User Emulation Attack, Objective Function Attack, Jamming Attack, Spectrum Sensing Data Falsification (SSDF), Control Channel Saturation DoS Attack (CCSD), Selfish Channel Negotiation (SCN), Sinkhole Attacks, HELLO Flood Attacks and Lion Attack. From the surveyed results, it is observed that the existing spectrum sensing, and prediction-based techniques consume more energy, and minimal data transmission rate for detecting the idle channel. Further, the end-to-end delay, energy consumption, end-to-end delay, and bandwidth are not minimized by the existing techniques. © 2016, Allerton Press, Inc.

Janani A.P.,Sri Krishna College of Engineering And Technology | Sakthivel M.,Anna University | Saravanan M.,Cr Engineering College
International Journal of Engineering and Technology | Year: 2013

Improving the performance of Mobile Ad hoc Network (MANET) routing protocols under highly mobile time sensitive communication scenario, like a military rescue operation, is a complex task since it reaches its optimum level of performance only after sometime. Our work proposes a modified version of AODV termed as AODV_HPR where certain nodes are assumed to be high energy transmission nodes known as High Power Routing (HPR) nodes, utilized for routing. The route is established only through HPR nodes which are capable of communicating to long distance. The simulation is performed in NS2 under varied node density with 50 percent HPR nodes and the results are compared with DSDV and AODV. The proposed AODV_HPR provided significant improvement in throughput and Packet Delivery Fraction (PDF) and significant reduction in dropped packets, end-to-end delay, MAC Load, routing load, energy consumption and overhead than conventional AODV.

Anandan V.K.,Indian Space Research Organisation Telemetry | Jagannatham D.B.V.,Cr Engineering College
IEEE Transactions on Geoscience and Remote Sensing | Year: 2010

An autonomous interference detection and filtering algorithm has been developed for removing the interference bands generated in the Doppler spectra of mesosphere-stratosphere-troposphere (MST) radar signals. The technique, implemented with the MST radar at Gadanki (13.5° N, 79° E), is based on identifying interferencelike band signals using a statistical signal variance approach for fixing the amplitude threshold, through which detecting the interference frequency and designing an adaptable notch filter to filter the undesired frequency bands are done. Signals received from the MST radar are sometimes contaminated with interference signals received from other objects or generated within the system through arcing of high-power devices. Multiple interference bands with different characteristics are observed in the power spectra, which contaminate the wind information and other atmospheric signals. The autonomous interference detection and filtering algorithm is applied to various cases, and it is found that the interference signals could effectively be removed, leaving behind the original signals. By this approach, the effective number of signal samples obtained is increased, which helps one to improve the temporal resolution. © 2009 IEEE.

Jeyabharathi J.,Cr Engineering College | Shanthi D.,PSNA College of Engineering and Technology
International Journal of Applied Engineering Research | Year: 2014

The rapid increase of available proteins, DNA and other biological sequences has made the problem of discovering the meaningful patterns from sequences, a major task for Bioinformatics research. Data mining of protein sequence databases poses special challenges, because several protein databases are non-relational whereas most of the data mining and machine learning techniques considers the data input to be a relational database. The existing sequence mining algorithms mainly focus on mining for subsequences. However, a wide range of applications such as biological DNA and protein motif mining needs an effective mining for identifying the approximate frequent patterns. The existing approximate frequent pattern mining algorithms have some delimitations such as lack of knowledge to finding the patterns, poor scalability and complexity to adapt into some other applications. In this paper, a Generalized Approximate Pattern Algorithm (GAPA) is proposed to efficiently mine the approximate frequent patterns in the protein sequence database. Pearson’s coefficient correlation is computed among the protein sequence database items to analyze the approximate frequent patterns. The performance of the proposed GAPA is analyzed and tested with the FASTA protein sequence database. FASTA database files hold the protein translations of Ensembl gene predictions. GAPA is compared with the existing methods such as Approximate Frequent Itemsets (AFI) tree and Approximate Closed Frequent Itemsets (ACFIM) in terms of support, accuracy, memory usage and time consumption. The experimental results shows GAPA is scalable and outperforms than the existing algorithms. © Research India Publications.

Venkateswarlu M.,Koneru Lakshmaiah College of Engineering | Mahamuda Sk.,Koneru Lakshmaiah College of Engineering | Swapna K.,Koneru Lakshmaiah College of Engineering | Prasad M.V.V.K.S.,Koneru Lakshmaiah College of Engineering | And 5 more authors.
Journal of Luminescence | Year: 2015

Abstract Lead Tungsten Tellurite (LTT) glasses doped with different concentrations of Ho3+ ions have been synthesized using the melt quenching method and characterized to understand their visible emission characteristic features using optical absorption and photoluminescence spectral studies. The Judd-Ofelt (JO) parameters measured from the absorption spectral features were used to evaluate radiative properties such as transition probability (AR), branching ratio (βR) and radiative lifetimes (τR) for the prominent fluorescent levels of Ho3+ ions in LTT glasses. The photoluminescence spectra recorded for all the Ho3+ doped LTT glasses at an excitation wavelength 452 nm gives three prominent emission transitions 5F4→5I8, 5F5→5I8 and 5F4→5I7, of which 5F4→5I8 observed in visible green region (546 nm) is relatively more intense than the other two transitions. The intensity of 5F4→5I8 emission transition in these glasses increases up to 1 mol% of Ho3+ ions and beyond concentration quenching is observed. Branching ratios (βR) and emission cross-sections (σse) were evaluated for the intense emission transition 5F4→5I8 in these glasses to understand the luminescence efficiency in visible green region (546 nm). The CIE chromaticity coordinates were also evaluated in order to understand the suitability of these glasses for visible luminescence. From the measured emission cross-sections and CIE coordinates, it was found that 1 mol% of Ho3+ ions in LTT glasses are most suitable for visible green luminescence in principle. © 2015 Elsevier B.V. All rights reserved.

Saravanan M.,Cr Engineering College | Sridhar S.,PSNA College of Engineering and Technology | Harikannan N.,PSNA College of Engineering and Technology
International Journal of Engineering and Technology | Year: 2014

A Hybrid flow shop scheduling is characterized 'n' jobs 'm' machines with 'M' stages by unidirectional flow of work with a variety of jobs being processed sequentially in a single-pass manner. The paper addresses the multi-stage hybrid flow shop scheduling problems with missing operations. It occurs in many practical situations such as stainless steel manufacturing company. The essential complexity of the problem necessitates the application of meta-heuristics to solve hybrid flow shop scheduling. The proposed Simulated Annealing algorithm (SA) compared with Particle Swarm Optimization (PSO) with the objective of minimization of makespan. It is show that the SA algorithm is efficient in finding out good quality solutions for the hybrid flow shop problems with missing operations.

Shanmugakala R.,Cr Engineering College | Tharmaraj P.,Thiagarajar College of Engineering | Sheela C.D.,The American College
Medicinal Chemistry Research | Year: 2014

A new series of transition metal complexes of 2,4-bis(indolin-3-one-2- ylimino)-6-phenyl-1,3,5-triazine) (BIPTZ) have been synthesized. The structural features of BIPTZ and metal(II) complexes were investigated using elemental analyses, magnetic susceptibility, molar conductance, mass, IR, UV-Vis, 1H NMR, 13C NMR, CV, and ESR spectral studies. Electronic absorption spectra and magnetic susceptibility measurements of the complexes predict their geometry. The redox behavior of the copper(II) complexes has been studied by cyclic voltammetry. All the synthesized compounds may serve as potential photoactive materials as indicated from their characteristic fluorescence spectrum. The Schiff base and its metal complexes were screened for anticonvulsant and anti-inflammatory activities in vivo. The metal(II) complexes are potent agents in treating neurochemical and behavioral abnormalities seen in Parkinson's diseased (PD) mice than free ligand. © 2013 Springer Science+Business Media New York.

Kandasamy V.K.,Alagappa Chettiar College of Engineering And Technology | Muthusamy S.,CR Engineering College | Pitchamuthu P.M.,Alagappa Chettiar College of Engineering And Technology
Advanced Materials Research | Year: 2014

The design process of shell and tube heat exchanger is difficult due to the complex geometric parameters with thermodynamic and fluid dynamic factors, which consume more time and minimum possibility for an optimum result in the case of conventional design. The optimum design of shell and tube heat exchanger was determined to predict optimum heat transfer coefficient with the effect of geometrical parameters such as number of baffles (NB), Shell diameter (Ds), Tube pitch (Pt) and Baffle spacing (LB). The analytical calculations were done using Response Surface Methodology on four factors, three level, central composite face centered design matrix with full replications technique by 95% confidence level. The results indicate that the geometrical parameters with optimum design. © (2014) Trans Tech Publications, Switzerland.

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