2,091 research outputs found
Disentangling the dominant drivers of gravity wave variability in the Martian thermosphere
In this study, we extracted the amplitudes of the gravity waves (GWs)from the
neutral densities measured in situ by the neutral gas and ion mass spectrometer
aboard the Mars atmosphere and volatile evolution mission. The spatial and
temporal variabilities of the GWs show that solar activity (the F10.7 cm solar
flux corrected for a heliocentric distance of 1.66 AU), solar insolation, and
the lower atmospheric dust are the dominant drivers of the GW variability in
the thermosphere. We developed a methodology in which a linear regression
analysis has been used to disentangle the complex variabilities of the GWs. The
three dominant drivers could account for most of the variability in the GW
amplitudes. Variability caused by the sources of GWs and the effects of winds
and the global circulation in the mesosphere and lower thermosphere are the
other factors that could not be addressed. The results of the present study
show that for every 100 sfu increase in the solar activity, the GW amplitudes
in the thermosphere decrease by ~9%. Solar insolation drives the diurnal,
seasonal and latitudinal variations of ~9%, ~4% and ~6%, respectively. Using
the historical data of the dust opacity and solar activity, we estimated the GW
amplitudes of the Martian thermosphere from MY 24 to MY 35. The GW amplitudes
were significantly reduced during the maximum of solar cycle 23 and were
highest in the solar minimum. The global dust storms of MY 25, 28, and 34 lead
to significant enhancements in the GW amplitudes.Comment: Accepted for publication in the astrophysical journal; 18 page
Application of Taguchi approach and Utility Concept in solving the Multi-objective Problem when
The traditional Taguchi method is widely used for optimizing the process parameters of a single response problem. Optimizationof a single response results the non-optimum values for remaining. But, the performance of the manufactured products isoften evaluated by several quality characteristics/responses. Under such circumstances, multi-characteristics response optimizationmay be the solution to optimize multi-responses simultaneously. In the present work, a multi-characteristics responseoptimization model based on Taguchi and Utility concept is used to optimize process parameters, such as speed, feed, depthof cut, and nose radius on multiple performance characteristics, namely, surface roughness (Ra) and material removal rate(MRR) during turning of AISI 202 austenitic stainless steel using a CVD coated cemented carbide tool. Taguchi’s L8 orthogonalarray (OA) is selected for experimental planning. The experimental result analysis showed that the combination of higherlevels of cutting speed, depth of cut, and nose radius and lower level of feed is essential to achieve simultaneous maximizationof material removal rate and minimization of surface roughness. The ANOVA and F-tests are used to analyze the results.Further, the confirmation tests are conducted and the results are found to be within the confidence interval
PCO-IB: Churn Analysis P2P Networks Using A Peer Co-Operative Intensive Based Schema
The Peer-to-Peer networks used technology of distributed computing. The P2P network is essential for network communication. P2P networks are utilized in many applications due to these benefits. For example, record sharing, broadcast communications, and media streaming. There are a lot of nodes connected to the P2P network. Peers of network frequently join and leave the network at the same time. In the P2P network, this kind of paradigm is called churn. Numerous new examination works uncovered that stir is the primary issue looked by the present P2P organization. Content availability, data accuracy, and overhead were significantly reduced by the churn process. An Incentive-Based (IB) schema was proposed in this paper in order to circumvent the limitations of the P2P network for multimedia transmission. The IB schema that has been proposed encourages fair communication and cooperation among the nodes. Multimedia transmission efficiency in real-time P2P networks is maximized by the IB schema. In this paper, IB outline for the most part centered around the upgrade of the P2P organizations. The proposed construction is carried out utilizing Organization Test system. In P2P networks, the proposed IB schema improved multimedia transmission performance
Domain swapping in human αA and αB crystallins affects oligomerization and enhances chaperone-like activity
αA and αB crystallins, members of the small heat shock protein family, prevent aggregation of proteins by their chaperone-like activity. These two proteins, although very homologous, particularly in the C-terminal region, which contains the highly conserved "α-crystallin domain," show differences in their protective ability toward aggregation-prone target proteins. In order to investigate the differences between αA and αB crystallins, we engineered two chimeric proteins, αANBC and αBNAC, by swapping the N-terminal domains of αA and αB crystallins. The chimeras were cloned and expressed in Escherichia coli. The purified recombinant wild-type and chimeric proteins were characterized by fluorescence and circular dichroism spectroscopy and gel permeation chromatography to study the changes in secondary, tertiary, and quaternary structure. Circular dichroism studies show structural changes in the chimeric proteins. αBNAC binds more 8-anilinonaphthalene-1-sulfonic acid than the αANBC and the wild-type proteins, indicating increased accessible hydrophobic regions. The oligomeric state of αANBC is comparable to wild-type αB homoaggregate. However, there is a large increase in the oligomer size of the αBNAC chimera. Interestingly, swapping domains results in complete loss of chaperone-like activity of αANBC, whereas αBNAC shows severalfold increase in its protective ability. Our findings show the importance of the N- and C-terminal domains of αA and αB crystallins in subunit oligomerization and chaperone-like activity. Domain swapping results in an engineered protein with significantly enhanced chaperone-like activity
DETECTION OF PHISHING WEBSITES USING HYBRID MODEL
Online technologies have revolutionized the modern computing world. Thereare number of users who purchase products online and make payment through variouswebsites. There are multiple websites who ask user to provide sensitive data such asusername, password or credit card details etc. often for malicious reasons. This type ofwebsite is known as phishing website. The phishing website can be detected based on someimportant characteristics like URL (Uniform Resource Locator) and Domain identity.Several approaches have been proposed for detection of phishing websites by extracting thephishing data sets criteria to classify their legitimacy. However, there is no such approachthat can provide better results to the users from phishing attacks. This paper is an attemptto contribute in that area by presenting a hybrid model for classification to detect phishingwebsites with high accuracy and less error rate
Comparison of the antioxidant activity and total phenolic, flavonoid content of aerial part of Cleome viscosa L.
Cleome viscosa L. (Capparidaceae), commonly known as “wild mustard”, is an annual, sticky herb found as common weed all over the plains of India and throughout the tropics of the world. In traditional systems of medicine the plant is reported to possess beneficial effects as an anthelmintic, antiseptic, carminative, antiscorbutic, febrifuge, and cardiac stimulant.    The aim of the present study was to evaluate to antioxidant activity of 70% methnolic extract of leaf and stem part of Cleome viscosa (CV) by using different in vitro model such as β carotene bleaching assay, reducing power and free radical scavenging activity (DPPH and hydroxyl radical scavenging activity). Total phenolic content were estimated by the Folin–Ciocalteu colorimetric method using gallic acid as standard and expressed as mg/g gallic acid equivalent (GAE) and total flavonoid content was estimated by aluminium chloride colourimetric method. The total phenolic, flavonoid content and antioxidant activity of Cleome viscosa leaves were found to be 66.38±0.82mg/g, 0.54±0.04mg/g and 77.30% respectively. Cleome viscosa leaves showed high free radical scavenging activity as evidenced by the low IC50 values in both DPPH (1,1-diphenyl-2-picryl hydrazyl) (373.18 μg/ml) and hydroxyl radical (573.55 μg/ml) methods. Cleome viscosa leaves possess high phenolic, flavonoid content and potential antioxidant activity, reducing power and free radical scavenging activity in comparison to stem
A Novel Method to Improve the Efficiency of Classification Phase of a Decision Tree
So far, most of the research on classification algorithms in machine learning has been focused only on improving the training speed and further improving the technical performance evaluation measures of the constructed models. There is no focus on improving the runtime efficiency of the classification phase which is much required in some critical applications. In this paper, we are considering the computation complexity of a decision tree's classification phase as the major criterion. A novel approach has been proposed to predict the class label of an unseen instance using the decision tree in less time than the regular tree traversal method. In the proposed method, the constructed decision tree is represented in the form of arrays. Then, the process of finding the class label is carried out by performing the bitwise operations between the elements of the arrays and test instance. Empirical results on various UCI data sets proved that the proposed method outperforms the standard method and five other benchmark classifiers and its classification is at least four times faster than the regular method
A Hybrid Digital Watermarking Approach Using Wavelets and LSB
The present paper proposed a novel approach called Wavelet based Least Significant Bit Watermarking (WLSBWM) for high authentication, security and copyright protection. Alphabet Pattern (AP) approach is used to generate shuffled image in the first stage and Pell’s Cat Map (PCM) is used for providing more security and strong protection from attacks. PCM applied on each 5×5 sub images. A wavelet concept is used to reduce the dimensionality of the image until it equals to the size of the watermark image. Discrete Cosign Transform is applied in the first stage; later N level Discrete Wavelet Transform (DWT) is applied for reducing up to the size of the watermark image. The water mark image is inserted in LHn Sub band of the wavelet image using LSB concept. Simulation results show that the proposed technique produces better PSNR and similarity measure. The experimental results indicate that the present approach is more reliable and secure efficient.The robustness of the proposed scheme is evaluated against various image-processing attacks
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