3,439 research outputs found
Performance analysis of unsupervised feature selection methods
Feature selection (FS) is a process which attempts to select more informative
features. In some cases, too many redundant or irrelevant features may
overpower main features for classification. Feature selection can remedy this
problem and therefore improve the prediction accuracy and reduce the
computational overhead of classification algorithms. The main aim of feature
selection is to determine a minimal feature subset from a problem domain while
retaining a suitably high accuracy in representing the original features. In
this paper, Principal Component Analysis (PCA), Rough PCA, Unsupervised Quick
Reduct (USQR) algorithm and Empirical Distribution Ranking (EDR) approaches are
applied to discover discriminative features that will be the most adequate ones
for classification. Efficiency of the approaches is evaluated using standard
classification metrics.Comment: 7 pages, Conference Publication
Influence of gravity waves and tides on mesospheric temperature inversion layers: simultaneous Rayleigh lidar and MF radar observations
Three nights of simultaneous Rayleigh lidar temperature measurements over Gadanki (13.5° N, 79.2° E) and medium frequency (MF) radar wind measurements over Tirunelveli (8.7° N, 77.8° E) have been analyzed to illustrate the possible effects due to tidal-gravity wave interactions on upper mesospheric inversion layers. The occurrence of tidal gravity wave interaction is investigated using MF radar wind measurements in the altitude region 86–90 km. Of the three nights, it is found that tidal gravity wave interaction occurred in two nights. In the third night, diurnal tidal amplitude is found to be significantly larger. As suggested in Sica et al. (2007), mesospheric temperature inversion seems to be a signature of wave saturation in the mesosphere, since the temperature inversion occurs at heights, when the lapse rate is less than half the dry adiabatic lapse rate
Image Encryption Based on Diffusion and Multiple Chaotic Maps
In the recent world, security is a prime important issue, and encryption is
one of the best alternative way to ensure security. More over, there are many
image encryption schemes have been proposed, each one of them has its own
strength and weakness. This paper presents a new algorithm for the image
encryption/decryption scheme. This paper is devoted to provide a secured image
encryption technique using multiple chaotic based circular mapping. In this
paper, first, a pair of sub keys is given by using chaotic logistic maps.
Second, the image is encrypted using logistic map sub key and in its
transformation leads to diffusion process. Third, sub keys are generated by
four different chaotic maps. Based on the initial conditions, each map may
produce various random numbers from various orbits of the maps. Among those
random numbers, a particular number and from a particular orbit are selected as
a key for the encryption algorithm. Based on the key, a binary sequence is
generated to control the encryption algorithm. The input image of 2-D is
transformed into a 1- D array by using two different scanning pattern (raster
and Zigzag) and then divided into various sub blocks. Then the position
permutation and value permutation is applied to each binary matrix based on
multiple chaos maps. Finally the receiver uses the same sub keys to decrypt the
encrypted images. The salient features of the proposed image encryption method
are loss-less, good peak signal-to-noise ratio (PSNR), Symmetric key
encryption, less cross correlation, very large number of secret keys, and
key-dependent pixel value replacement.Comment: 14 pages,9 figures and 5 tables;
http://airccse.org/journal/jnsa11_current.html, 201
Variabilities of mesospheric tides and equatorial electrojet strength during major stratospheric warming events
The present study demonstrates the relationship between the high latitude northern hemispheric major sudden stratospheric warming (SSW) events and the reversal in the afternoon equatorial electrojet (EEJ), often called the counter-electrojet (CEJ), during the winter months of 1998–1999, 2001–2002, 2003–2004 and 2005–2006. As the EEJ current system is driven by tidal winds, an investigation of tidal variabilities in the MF radar observed zonal winds during the winters of 1998–1999 and 2005–2006 at 88 km over Tirunelveli, a site close to the magnetic equator, shows that there is an enhancement of semi-diurnal tidal amplitude during the days of a major SSW event and a suppression of the same immediately after the event. The significance of the present results lies in demonstrating the latitudinal coupling between the high latitude SSW phenomenon and the equatorial ionospheric current system with clear evidence for major SSW events influencing the day-to-day variability of the CEJ
Low carbon building: Experimental insight on the use of fly ash and glass fibre for making geopolymer concrete
Due to the environmental impacts resulting from the production of Ordinary Portland cement (OPC), the
drive to develop alternative binders that can totally replace OPC is gaining huge consideration in the
construction field. In the current study, attempt was made to determine the strength characteristics of
glass fibre-reinforced fly ash based geopolymer concrete. Sodium hydroxide (NaOH) and sodium silicate
(Na2SiO3) were used as alkaline solutions (for activation of geopolymer reaction) at 12, 16, 20 M. Glass
fibres were added to the geopolymer concrete in varying proportions of 0.1e0.5% (in steps of 0.1%) by
weight of concrete. A constant weight ratio of alkaline solution to fly ash content of 0.43 was adopted for
all mixes. British standard concrete test specimens were cast for measuring compressive strength, splittensile
strength, and flexural strength. Concrete specimens were cured by heating in oven at 90 �C for
24 h and natural environment, respectively. From the results, thermally cured concrete samples had
better mechanical properties than the ambient (natural) cured samples. Thermally cured concrete
specimen, containing 0.3% glass fibre and 16 M NaoH, achieved a maximum compressive strength of
24.8 MPa after 28 d, while naturally cured samples achieved a strength of 22.2 MPa. There was substantial
increase in tensile strength of geopolymer concrete due to the addition of glass fibres. Split
tensile strength increased by 5e10% in glass fibre-reinforced geopolymer concrete, containing 0.1e0.5%
glass fibre and 16 M NaoH when compared to the unreinforced geopolymer concrete (1.15 MPa)
Development of Web Application Framework for Lean Assessment Approach
Lean manufacturing is a process of eliminating non value added activities in an Industry. Non value added activities (NVA) are the activities, which does not add values to the products made in the industry. Industry uses either lean team or external lean consultant to carry out the lean manufacturing process. Lean manufacturing software is a web based application which helps the lean team as well as lean consultant to carry out their process in faster, reliable way of approaching their results. The Database Management System connected to web application stores, calculate and manipulate the data which are collected from data collection process and provide statistical data output which are further carried to decision phase by the lean team. An idea to make the lean implementation process go lean
Computational Analysis of Heat Transfer through Fins with Different Types of Notches
The Engine is one of the important component in an automobile which is subjected to high temperature and thermal stresses. In order to cool the engine the fins are another component which are used to dissipate the heat from the Engine. Fins are generally used to increase the heat transfer rate from the system to the surroundings. By doing computational flow analysis on the engine cooling fins, it is helpful to know about the heat dissipation rate and the Principle implemented in this project is to increase the heat transfer rate, so in this analysis, the fins are modified by putting different types of notches and are of same material. The knowledge of efficiency and effectiveness of the fins are necessary for proper designing of fins. The main objective of our analysis is to determine the flow of heat at various notches available and the analysis is done by using ANSYS – CFD Fluent software
Sonophotocatalytic mineralization of Norflurazon in aqueous environment
Norflurazon (4-chloro-5-(methylamino)-2-[3- trifluoromethyl)phenyl]pyridazin-3(2H)-one; C12H9ClF3N3O) is an excellent weed controlling agent being practiced in the agricultural lands. The excessive addition or the undissolved Norflurazon (maximum solubility 28 mg/L at 25 C) enters into the aquatic environment and causes the adverse effects associated with its high concentration. To avoid the perilous effects, visible light assisted photocatalysis set-up coupled with the 42 kHz ultrasound producing bath type sonicator is used to completely mineralize the Norflurazon. TiO2, ZnO and gold loaded zinc oxide nanocatalysts were utilized to study the mineralization of Norflurazon. AueZnO shows the greater efficiency for the sonophotocatalytic removal of Norflurazon among the various nanocatalysts employed to study the mineralization. The order of Norflurazon mineralization was sonophotocatalysis > sonocatalysis > photocatalysis. The additive effect was achieved for the sonophotocatalytic degradation. The high performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometric (LCMS) analyses were employed to identify the various intermediates produced during the mineralization. The identification of four pseudo molecular ions and various intermediates using the LCMS analysis evidently suggests the sonophotocatalytic degradation was preceded in various decay pathways. A suitable mechanism has been proposed for the sonophotocatalytic mineralization of Norflurazo
Poly-Gamma-Glutamic Acid (γ-PGA)-based encapsulation of Adenovirus to evade neutralizing antibodies.
In recent years, there has been an increasing interest in oncolytic adenoviral vectors as an alternative anticancer therapy. The induction of an immune response can be considered as a major limitation of this kind of application. Significant research efforts have been focused on the development of biodegradable polymer poly-gamma-glutamic acid (γ-PGA)-based nanoparticles used as a vector for effective and safe anticancer therapy, owing to their controlled and sustained-release properties, low toxicity, as well as biocompatibility with tissue and cells. This study aimed to introduce a specific destructive and antibody blind polymer-coated viral vector into cancer cells using γ-PGA and chitosan (CH). Adenovirus was successfully encapsulated into the biopolymer particles with an encapsulation efficiency of 92% and particle size of 485 nm using the ionic gelation method. Therapeutic agents or nanoparticles (NPs) that carry therapeutics can be directed specifically to cancerous cells by decorating their surfaces using targeting ligands. Moreover, in vitro neutralizing antibody response against viral capsid proteins can be somewhat reduced by encapsulating adenovirus into γ-PGA-CH NPs, as only 3.1% of the encapsulated adenovirus was detected by anti-adenovirus antibodies in the presented work compared to naked adenoviruses. The results obtained and the unique characteristics of the polymer established in this research could provide a reference for the coating and controlled release of viral vectors used in anticancer therapy.This work was funded by the Ministry of Higher Education and Scientific Research (Iraq). This work was also partially funded by the Research Investment Fund, University of Wolverhampton (Wolverhampton, United Kingdom) and the Italian Ministry of University and Research (MIUR)
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