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Dhanaraj S.,Sree Saraswathi Thyagaraja College | Karthikeyani V.,Thiruvalluvar Government Arts College
Proceedings of the 2013 International Conference on Pattern Recognition, Informatics and Mobile Engineering, PRIME 2013 | Year: 2013

Spam filters are the most used software tool used by businesses and individual to block spam mails entering into their mail boxes. Until recently, majority of research effort was expended on controlling text-based spam emails. However, the past few years have envisaged a novel approach, where the spammers embed the text message into an image. Thus, the anti-spam filtering research is forced to move from text-based techniques to image-based techniques. Spam and the spam blockers designed to combat it have spawned an upsurge in creativity and innovation. Many software developers are developing new and every more effective spam filtering software. All the methods have a common dream that is to eliminate 100% of the spam, which is still not a reality. To reduce the gap between this reality and dream, researchers have proposed many different types of spam filters and this paper provides a review of them. © 2013 IEEE. Source

Selvapandiyan M.,Sri Vidya Mandir Arts and Science College | Arumugam J.,Sri Vidya Mandir Arts and Science College | Sundaramoorthi P.,Thiruvalluvar Government Arts College | Sudhakar S.,National Physical Laboratory India
Journal of Alloys and Compounds | Year: 2013

The influence of MgSO4 doping on the properties of zinc tris-thiourea sulphate single crystals grown at room temperature by slow evaporation solution growth technique was studied. Powder XRD analysis confirmed the orthorhombic crystal structure with noncentrosymmetric space group Pca21. The mechanical properties of the grown crystals were analysed by Vicker's microhardness method. Functional groups present in the materials were identified by FTIR spectral analysis in the range between 4000 and 400 cm1. The UV-Vis spectrum indicates that the UV cut-off wavelength of the crystals has less than 297 nm. The thermal stability of the grown crystals was determined with the aid of thermo-gravimetric analysis (TGA) and differential scanning calorimetry (DSC). Second order nonlinear optical behaviour of the grown crystals have been confirmed by Kurtz powder second harmonic generation (SHG) test. © 2013 Elsevier B.V. All rights reserved. Source

Selvapandiyan M.,Bharathiar University | Sudhakar S.,Chonbuk National University | Sundaramoorthi P.,Thiruvalluvar Government Arts College
Journal of Alloys and Compounds | Year: 2012

Pure and KI doped single crystals of ZTS were grown by slow evaporation technique. The grown crystals were subjected to X-ray diffraction, UV-visible spectrum, FTIR analysis, micro hardness studies, TGA/DSC and SHG. X-ray diffraction analysis revealed that the structure of grown crystal belongs to orthorhombic system. The mechanical property of the grown crystals has been analyzed by Vickers microhardness method. Optical transparency of the grown crystals was studied by UV-visible spectroscopic method. The functional groups and modes of vibrational frequencies have been identified by using FTIR spectral data. The thermal stability of the grown crystal was investigated using thermo gravimetric analysis and differential scanning calorimetry (TGA/DSC) studies. Second harmonic generation was confirmed by using Nd: YAG laser. The analysis results confirmed that these crystals have better nonlinearity and good mechanical strength than KDP. © 2012 Elsevier B.V. Source

Moorthy M.,Muthayammal Engineering College | Sathiyabama S.,Thiruvalluvar Government Arts College
Journal of Computer Science | Year: 2012

Problem statement: In 802.11-based Wireless LAN (WLAN), there is an mproved risk of security attacks. To defeat concealed attacks, there is a necessity to authenticate both access points and wireless stations. Approach: We propose a defensive technique for DDoS attack in WLAN. This authentication technique includes an Authentication Server (AS) in addition to the Wireless Station (WS) and Access Point (AP). Results: The authentication server holds both normal and attacker databases. The attacker database can be constructed from the outcome of fuzzy decision making. After WS and AP registers itself with AS, WS sends authentication request message to AS through the nearest AP. Before granting the session key for the WS, the AS checks the occurrence of WS in the attacker database. If it is found to be an attacker, AS denies the session key for the WS, there by isolating the WS from further communications. In order to prevent the authentication request flooding attacks, traffic pattern filtering rule is implemented. Conclusion/Recommendations: By simulation results, we show that the proposed technique is more efficient defensive mechanism against DDoS attack. © 2012 Science Publications. Source

Sundaramoorthi P.,Thiruvalluvar Government Arts College
Optik | Year: 2015

Single crystals of urea with l-alanine were grown by low temperature solution growth method from aqueous solution. The cell parameters and crystalline nature of the grown crystals were determined from single and powder X-ray diffraction studies. The qualitative analyses of the presence of functional groups in the grown crystals were estimated from FTIR analysis. The UV-visible spectrum reveals the optical property of the grown crystal. The second harmonic generating (SHG) properties are demonstrated using Kurtz-Perry powder technique. Photoluminescence shows that the grown crystal has a blue fluorescence emission. Photoconductivity study reveals the negative photoconductivity nature of the crystal. The low value of dielectric loss with high frequency for these samples suggests that the samples possess enhanced optical quality with lesser defects and this parameter is of vital importance. © 2015 Elsevier GmbH. All rights reserved. Source

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