ReP-ETD: A Repetitive Preprocessing technique for Embedded Text Detection from images in spam emails

Email service proves to be a convenient and powerful communication tool. As internet continues to grow, the type of information available to user has shifted from text only to multimedia enriched. Embedded text in multimedia content is one of the prevalent means for delivering messages to content viewers. With the increasing importance of emails and the incursions of internet marketers, spam has become a major problem and has given rise to unwanted mails. Spammers are continuously adopting new techniques to evade detection. Image spam is one such technique where in embedded text within images carries the main information of the spam message instead of text based spam. Currently, image spam is evaluated to be roughly 50% of all spam traffic and is still on the rise, thus a serious research issue. Filtering mails is one of the popular approaches used to block spam mails. This work proposes new model ReP-ETD (Repetitive Pre-processing technique for Embedded Text Detection) for efficiently and accurately detecting spam in email images. The performance of the proposed ReP-ETD model has been evaluated across the identified parameters and compared with other existing models. The simulation results demonstrate the effectiveness of the proposed model

Hydrodynamics of domain growth in nematic liquid crystals

We study the growth of aligned domains in nematic liquid crystals. Results are obtained solving the Beris-Edwards equations of motion using the lattice Boltzmann approach. Spatial anisotropy in the domain growth is shown to be a consequence of the flow induced by the changing order parameter field (backflow). The generalization of the results to the growth of a cylindrical domain, which involves the dynamics of a defect ring, is discussed.Comment: 12 revtex-style pages, including 12 figures; small changes before publicatio

A Surface Plasmon Resonance Investigation of the Selective Interaction of Organic Vapors with Cavitands

A class of supramolecules, called cavitands, that have been shown to exhibit discotic phases depending on the structure, are shown to have potential for sensing applications. Certain cavitands (macrocyclic compounds based on resorcinarenes) display selectivity of interactions with organic vapors. We use Surface Plasmon Resonance (SPR) to demonstrate this principle. The two cavitands chosen for this study, had both a different size and shape of the preorganized cavity and were exposed to a variety of aromatic and chlorinated hydrocarbons. QxCav-1 (cavitand) was found to have a marked preference for the aromatic compounds; with the sequence of selectivity, determined by SPR to be nitrobenzene > toluene > benzene. MeCav-2 (cavitand) on the other hand, showed higher selectivity to dichloromethane with respect to aromatic vapors at room temperature. Cavitands therefore represent attractive sensing materials, with potential for application in devices using optical transduction schemes based on a refractive index change

Supramolecular Surface Plasmon Resonance (SPR) Sensors for Organophosphorus Vapor Detection.

We synthesized cavitands containing COOH moieties at the upper rim of the cavity and evaluated the interaction between these cavitands and the sarin nerve gas simulant, dimethylmethylphosphonate (DMMP) using surface plasmon resonance (SPR) spectroscopy. The carboxylic acid group on the cavitand is expected to form a hydrogen bond with the P=O group of the organophosphorus vapors. Films of these cavitands produced a rapid and reversible SPR response to low concentrations of DMMP. We observed concentration dependent sorption of the DMMP molecule into the COOH containing layer in the ppb to ppm range. Spin-cast films and Langmuir-Blodgett (LB) depositions of bilayer thick cavitand films produced identical SPR shifts upon exposure to DMMP. The sensitivity of the sensor was enhanced via LB deposition of multiple bilayers. Eight-layer-thick films of the COOH cavitand showed sensitivity to DMMP concentrations as low as 16 ppb. The orientation of the COOH group into or out of the cavitand did not affect DMMP binding, but strongly influenced the water uptake. In both cases the molecular recognition event responsible for the DMMP uptake has been elucidated via crystal structure analyses of the complexes of COOH in/out cavitands with DMMP. Furthermore, we demonstrated that the COOH containing cavitand had an SPR sensitivity to DMMP higher than the standard fluoropolyol sensing layer, and that the cavitand layer was less prone to water vapor and alcohol interferences. Hence, cavitand layers containing a COOH moiety are promising for use as sensitive and specific sensors for nerve gas agents

Influence of Cavity Depth on the Responses of SPR Sensors Coated with Self-Assembled Monolayers of Cavitands

Cavitands are synthetic organic compounds with enforced cavities of molecular dimensions. Cavitand Self-assembled Monolayers are shown to be highly responsive materials for SPR based chemical vapor sensing. The SAM approach permits an unambiguous comparison of the influence of cavity depth and synergistic interactions between cavitand and guest molecule. This eliminates the possibility of response biases arising from differences in sensing layer morphology. Consistent with earlier results on spin coated cavitands, aromatic vapors are selectively complexed within cavitand 3 (quinoxaline-bridged cavitand) and show lesser affinity for cavitand 2 (pyrazine-bridged cavitand) and cavitand 1 (methylene-bridged cavitand) owing to their smaller cavity depths. Cavitand 1, with its meniscus shaped pi basic cavity, selectively interacts only with small molecules with acidic methyl groups such as nitromethane and acetonitrile. Modeling results corroborate the experimental data and show that increased van der Waals interactions within cavitand 3 are responsible for the higher selectivity towards aromatic vapors

Orientation of Cavitands at Air/Water and Air/Solid Interfaces Studied by SHG

Surface second harmonic generation (SHG) was used to probe orientation of cavitand molecules deposited on water as Langmuir films and on fused silica substrates either bare or functionalized with a surfactant. Measurements performed during compression of the Langmuir films reveal that while the surface density may vary, molecules always appear more or less oriented with their long axis perpendicular to the water surface. Phase measurements indicate that the vase-like heads of the molecules cover the water for Langmuir films, but face the air for monolayers spread on surfactant-coated substrates

Ekrv: Ensemble of knn and random committee using voting for efficient classification of phishing

Any efficient anti-phishing tool must be able to classify phishing activity as ‘phishing’ with utmost accuracy. The key factor that influences the accuracy of an anti-phishing tool is the selection of a classification algorithm whose prediction accuracy is the maximum with nil or least false-positive rate. This paper proposes the implementation of a hybrid approach involving random committee that is a type of Ensemble classification technique and k-nearest neighbor (kNN) algorithm which is available as IBK (instance-based with k neighbors) on WEKA, resulting in most encouraging prediction accuracy values. The proposed scheme is followed after the preprocessing phase that involves feature extraction using Consistency Subset Eval algorithm with the Greedy Stepwise search technique