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Noise Cancellation using Adaptive Filtering in ECG Signals : Application to Biotelemetry
Rajvansh Sehamby,Buta Singh 보안공학연구지원센터 2016 International Journal of Bio-Science and Bio-Techn Vol.8 No.2
The ECG (electrocardiogram) is a system that provides patient’s critical heart activity. The adaptive electrocardiogram filter will be designed to reduce noise caused by external systems & body artifacts. This paper aims to help to reduce the noise interference in the ECG signals and better diagnose results. Some of the most common examples of noise that the ECG filter would need to remove in order to give useful results includes power line interference, motion artifacts, muscle contraction, electrode contact noise and interference caused due other electronic equipment. ECG signals are weak and easily susceptible to noise and interference. In this paper I have presented an implementation of Least Mean Squares (LMS).
ARRAKIS: atlas of resonance rings as known in the S<sup>4</sup>G
Comeró,n, S.,Salo, H.,Laurikainen, E.,Knapen, J. H.,Buta, R. J.,Herrera-Endoqui, M.,Laine, J.,Holwerda, B. W.,Sheth, K.,Regan, M. W.,Hinz, J. L.,Muñ,oz-Mateos, J. C.,Gil de Paz, A.,Men&eac Springer-Verlag 2014 Astronomy and astrophysics Vol.562 No.-
<P>Context. Resonance rings and pseudorings (here collectively called rings) are thought to be related to the gathering of material near dynamical resonances caused by non-axisymmetries in galaxy discs. This means that they are the result of secular evolution processes that redistribute material and angular momentum in discs. Studying them may give clues on the formation and growth of bars and other disc non-axisymmetries. Aims. Our aims are to produce a catalogue and an atlas of the rings detected in the Spitzer Survey of Stellar Structure in Galaxies (S<SUP>4</SUP>G) and to conduct a statistical study of the data in the catalogue. Methods. We traced the contours of rings previously identified and fitted them with ellipses. We found the orientation of bars by studying the galaxy ellipse fits from the S<SUP>4</SUP>G pipeline 4. We used the galaxy orientation data obtained by the S<SUP>4</SUP>G pipeline 4 to obtain intrinsic ellipticities and orientations of rings and the bars. Results. ARRAKIS contains data on 724 ringed galaxies in the S<SUP>4</SUP>G. The frequency of resonance rings in the S<SUP>4</SUP>G is of 16 ±1% and 35 ±1% for outer and inner features, respectively. Outer rings are mostly found in Hubble stages −1 ≤T≤ 4. Inner rings are found in a broad distribution that covers the range −1 ≤T≤7. We confirm that outer rings have two preferred orientations, namely parallel and perpendicular to the bar. We confirm a tendency for inner rings to be oriented parallel to the bar, but we report the existence of a significant fraction (maybe as large as 50%) of inner features that have random orientations with respect to the bar. These misaligned inner rings are mostly found in late-type galaxies (T ≥4). We find that the fraction of barred galaxies hosting outer (inner) rings is ~1.7 times (~1.3 times) that in unbarred galaxies. Conclusions. We confirm several results from previous surveys as well as predictions from simulations of resonant rings and/or from manifold flux tube theory. We report that a significant fraction of inner rings in late-type galaxies have a random orientation with respect to the bar. This may be caused by spiral modes that are decoupled from the bar and dominate the Fourier amplitude spectrum at the radius of the inner ring. The fact that rings are only mildly favoured by bars suggests that those in unbarred galaxies either formed because of weak departures from the axisymmetry of the galactic potential or that they are born because of bars that were destroyed after the ring formation.</P>
Meidt, Sharon E.,Schinnerer, Eva,Knapen, Johan H.,Bosma, Albert,Athanassoula, E.,Sheth, Kartik,Buta, Ronald J.,Zaritsky, Dennis,Laurikainen, Eija,Elmegreen, Debra,Elmegreen, Bruce G.,Gadotti, Dimitri IOP Publishing 2012 The Astrophysical journal Vol.744 No.1
<P>With the aim of constructing accurate two-dimensional maps of the stellar mass distribution in nearby galaxies from Spitzer Survey of Stellar Structure in Galaxies 3.6 and 4.5 mu m images, we report on the separation of the light from old stars from the emission contributed by contaminants. Results for a small sample of six disk galaxies (NGC 1566, NGC 2976, NGC 3031, NGC 3184, NGC 4321, and NGC 5194) with a range of morphological properties, dust content, and star formation histories are presented to demonstrate our approach. To isolate the old stellar light from contaminant emission (e.g., hot dust and the 3.3 mu m polycyclic aromatic hydrocarbon (PAH) feature) in the IRAC 3.6 and 4.5 mu m bands we use an independent component analysis (ICA) technique designed to separate statistically independent source distributions, maximizing the distinction in the [3.6]-[4.5] colors of the sources. The technique also removes emission from evolved red objects with a low mass-to-light ratio, such as asymptotic giant branch (AGB) and red supergiant (RSG) stars, revealing maps of the underlying old distribution of light with [3.6]-[4.5] colors consistent with the colors of K and M giants. The contaminants are studied by comparison with the non-stellar emission imaged at 8 mu m, which is dominated by the broad PAH feature. Using the measured 3.6 mu m/8 mu m ratio to select individual contaminants, we find that hot dust and PAHs together contribute between similar to 5% and 15% to the integrated light at 3.6 mu m, while light from regions dominated by intermediate-age (AGB and RSG) stars accounts for only 1%-5%. Locally, however, the contribution from either contaminant can reach much higher levels; dust contributes on average 22% to the emission in star-forming regions throughout the sample, while intermediate-age stars contribute upward of 50% in localized knots. The removal of these contaminants with ICA leaves maps of the old stellar disk that retain a high degree of structural information and are ideally suited for tracing stellar mass, as will be the focus in a companion paper.</P>