412 research outputs found
Towards applying FCM with DBSCAN for Detecting DDoS Attack in Cloud Infrastructure to Improve Data Transmission Rate
Cloud is a pay-to-use technology which can be used to offer IT resources instead of buying computer hardware. It is time saving and cheaper technology. This paper analyzes the DDoS attack on cloud infrastructure and can be detected by using FCM with DBSCAN hybrid algorithm that classifies the clusters of data packets and detects the outlier in that particular data packet. The experimental outcome shows that the enhanced hybrid approach has better results in detecting the DDoS attack. The DDoS attack targets the main host of the cloud infrastructure by sending unwanted packets. This attack is a major threat to the network security. The FCM with DBSCAN hybrid approach detects outliers and also assigns one specific data point in clusters to detect DDoS attack in cloud infrastructure. By using this hybrid approach the data can be grouped as clusters and the data beyond the noise level can also be detected. This algorithm helps in identifying the data that are vulnerable to DDoS attack. This detection helps in improving the data transmission rate
Cellular Automata with Synthetic Image A Secure Image Communication with Transform Domain
Image encryption has attained a great attention due to the necessity to safeguard confidential images. Digital documents, site images, battlefield photographs, etc. need a secure approach for sharing in an open channel. Hardware â software co-design is a better option for exploiting unique features to cipher the confidential images. Cellular automata (CA) and synthetic image influenced transform domain approach for image encryption is proposed in this paper. The digital image is initially divided into four subsections by applying integer wavelet transform. Confusion is accomplished on low â low section of the transformed image using CA rules 90 and 150. The first level of diffusion with consecutive XORing operation of image pixels is initiated by CA rule 42. A synthetic random key image is developed by extracting true random bits generated by Cyclone V field programmable gate array 5CSEMA5F31C6. This random image plays an important role in second level of diffusion. The proposed confusion and two level diffusion assisted image encryption approach has been validated through the entropy, correlation, histogram, number of pixels change rate, unified average change intensity, contrast and encryption quality analyses
Interfacial Hot Carrier Collection Controls Plasmonic Chemistry
Harnessing non-equilibrium hot carriers from plasmonic metal nanostructures
constitutes a vibrant research field. It promises to enable control of activity
and selectivity of photochemical reactions, especially for solar fuel
generation. However, a comprehensive understanding of the interplay of
plasmonic hot carrier-driven processes in metal/semiconducting heterostructures
has remained elusive. In this work, we reveal the complex interdependence
between plasmon excitation, hot carrier generation, transport and interfacial
collection in plasmonic photocatalytic devices, uniquely determining the charge
injection efficiencies at the solid/solid and solid/liquid interfaces.
Interestingly, by measuring the internal quantum efficiency of ultrathin (14 to
33 nm) single-crystalline plasmonic gold (Au) nanoantenna arrays on titanium
dioxide substrates, we find that the performance of the device is governed by
hot hole collection at the metal/electrolyte interface. In particular, by
combining a solid- and liquid-state experimental approach with ab initio
simulations, we show a more efficient collection of high-energy d-band holes
traveling in [111] orientation, resulting in a stronger oxidation reaction at
the {111} surfaces of the nanoantenna. These results thus establish new
guidelines for the design and optimization of plasmonic photocatalytic systems
and optoelectronic devices
Electrochemical capacitance of CO-terminated Pt(111) dominated by the CO-solvent gap
Catalysis and Surface Chemistr
STANDARDIZATION OF A SIDDHA FORMULATION AMUKKARA CURANAM BY HPTLC
Amukkara curanam, a Siddha formulation, currently used in all types of gastric disorders, rheumatic pain, insomnia and sexual insufficiency, was investigated for the estimation of the marker compounds, withaferine A and piperine contents in a prepared standard formulation and a commercial formulation by using HPTLC method of analysis. The two formulations were subjected to methanol, ethyl acetate and chloroform extractions by using Soxhhlet apparatus The chromatogram was developed using chloroform: methanol (8.5:1.5 v/v) and toluene: ethyl acetate (7:3 v/v) as mobile phases for the estimation of withferine A and piperine respectively. The detection and quantification were performed at a wavelength of 220 nm for withaferine A and 254 nm for piperine. The linear regression analysis of calibration plots of withferine A and piperine exhibited linear relationship in the range of 5 â 15 Âľg and 50 â 150 ng respectively, while the % recovery was found to be 94.52% w/w of withaferine A and 98.73%w/w of piperine, thus proving the accuracy and precision of the analysis. Methanol and ethyl acetate were found to be the suitable solvents for the extraction of withaferin A and piperine respectively. The withaferine A content in standard formulation was found to be much higher in all the three extracts than that of the commercial sample. However, the piperine content in all the three extracts of standard formulation was slightly lower than the respective extracts of commercial formulation. The proposed HPTLC method was found to be rapid, simple and accurate for quantitative estimation of withferine A and piperine in different formulation extracts
Evaluation of classical precipitation descriptions for Îłâ˛â˛(Ni3NbâD022) in Ni-base superalloys
The growth/coarsening kinetics of Îłâ˛â˛(Ni3NbâD022) precipitates have been found by numerous researchers to show an apparent correspondence with the classical (Ostwald ripening) equation outlined by Lifshitz, Slyozov and (separately) Wagner for a diffusion controlled regime. Nevertheless, a significant disparity between the actual precipitate size distribution shape and that predicted by LSW is frequently observed in the interpretation of these results, the origin of which is unclear. Analysis of the literature indicates one likely cause for this deviation from LSW for Îłâ˛â˛ precipitates is the âencounterâ phenomenon described by Davies et al. (Acta Metall 28(2):179â189, 1980) that is associated with secondary phases comprising a high volume fraction. Consequently, the distributions of both Îłâ˛â˛ precipitates described in the literature (Alloy 718) and measured in this research in Alloy 625 are analysed through employing the LifshitzâSlyozov-Encounter-Modified (LSEM) formulation (created by Davies et al.). The results of the LSEM analysis show good far better agreement than LSW with experimental distributions after the application of a necessary correction for what is termed in this research as âdirectional encounterâ. Moreover, the activation energy for Îłâ˛â˛ coarsening in Alloy 625 shows conformity with literature data once the effect of heterogeneous (on dislocations) precipitate nucleation at higher temperatures is accounted for
A Novel Coal-Associated Soil as an Effective Adsorbent for Reactive Blue Dye Removal
The project aims to remove reactive blue dye from the effluent of textile industries by utilizing coal-associated soil as an adsorbent, as it possesses effective physical properties and distinguishing characteristics. In comparison to other separation techniques, the adsorption method is the most effective, cost-effective, and straightforward. A batch adsorption investigation was carried out to examine the various adsorption-influencing factors, including solution pH, adsorbent dosage, contact time, temperature, and dye concentration. Contact time of 30 min, an adsorbent dosage of 10g.100 mL-1, a solution pH of 7, a temperature of 30°C, and an initial dye concentration of 100 mg.L-1 were found to be optimal for dye adsorption. Using two distinct kinetic models, the evaluation of kinetic studies revealed that the pseudo-second-order provided the greatest fit, with a higher R2 value than the pseudo-first-order. The thermodynamic parameters Gibbs free energy (ÎG°), entropy (ÎS°), and enthalpy (ÎH°) indicated that the current adsorption system was exothermic and spontaneous. Further study of the adsorption isotherm revealed that the Langmuir isotherm model provided the best fit, with an R2 value of 0.977%
Modelling Clock Synchronization in the Chess gMAC WSN Protocol
We present a detailled timed automata model of the clock synchronization
algorithm that is currently being used in a wireless sensor network (WSN) that
has been developed by the Dutch company Chess. Using the Uppaal model checker,
we establish that in certain cases a static, fully synchronized network may
eventually become unsynchronized if the current algorithm is used, even in a
setting with infinitesimal clock drifts
Quantum-mechanical effects in photoluminescence from thin crystalline gold films
Luminescence constitutes a unique source of insight into hot carrier
processes in metals, including those in plasmonic nanostructures used for
sensing and energy applications. However, being weak in nature, metal
luminescence remains poorly understood, its microscopic origin strongly
debated, and its potential for unravelling nanoscale carrier dynamics largely
unexploited. Here, we reveal quantum-mechanical effects emanating in the
luminescence from thin monocrystalline gold flakes. Specifically, we present
experimental evidence, supported by first-principles simulations, to
demonstrate its photoluminescence origin when exciting in the interband regime.
Our model allows us to identify changes to the measured gold luminescence due
to quantum-mechanical effects as the gold film thickness is reduced.
Excitingly, such effects are observable in the luminescence signal from flakes
up to 40 nm in thickness, associated with the out-of-plane discreteness of the
electronic band structure near the Fermi level. We qualitatively reproduce the
observations with first-principles modelling, thus establishing a unified
description of luminescence in gold and enabling its widespread application as
a probe of carrier dynamics and light-matter interactions in this material. Our
study paves the way for future explorations of hot-carriers and charge-transfer
dynamics in a multitude of material systems.Comment: Main text 21 pages and 4 figures. Supplemental Information 33 pages
and 17 figure
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