566 research outputs found
High Performance Power Spectrum Analysis Using a FPGA Based Reconfigurable Computing Platform
Power-spectrum analysis is an important tool providing critical information
about a signal. The range of applications includes communication-systems to
DNA-sequencing. If there is interference present on a transmitted signal, it
could be due to a natural cause or superimposed forcefully. In the latter case,
its early detection and analysis becomes important. In such situations having a
small observation window, a quick look at power-spectrum can reveal a great
deal of information, including frequency and source of interference. In this
paper, we present our design of a FPGA based reconfigurable platform for high
performance power-spectrum analysis. This allows for the real-time
data-acquisition and processing of samples of the incoming signal in a small
time frame. The processing consists of computation of power, its average and
peak, over a set of input values. This platform sustains simultaneous data
streams on each of the four input channels.Comment: 5 pages, 3 figures. Published in the Proceedings of the IEEE
International conference on Reconfigurable Computing and FPGAs (ReConFig
2006). Article also available at
http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=4100006&isnumber=409995
Intensity and polarization line profiles in a semi-infinite Rayleigh-scattering planetary atmosphere. III. Variation of polarization profiles and the Stokes parameter Q over the disk
The variation of the polarization profiles, the Stokes parameters Q and U, and the angle defining the plane of polarization along the intensity equator and along the mirror meridian, on which μ = μ0, in a Rayleigh scattering atmosphere is studied. It is found that these variations are more complex than thought hitherto, particularly at large phase angles
A reconsideration of the effective depth of line formation in planetary atmospheres
A new definition of the effective depth of line formation is given which incorporates its dependence on the angle of emergence as well as on the position within the line. Solution obtained for isotropic scattering in the third approximation of discrete ordinates explains: (i) Variation of equivalent widths over the disc; (ii) Inverse dependence of this variation on line strength; and (iii) The phase effect for relative equivalent widths
Intensity and Polarization line profiles in a semi-infinite Rayleigh-scattering planetary atmosphere. II. Variations of equivalent width over the disk
The study of the variation of equivalent width in a Rayleighscattering planetary atmosphere along the intensity equator and along the mirror meridian on which μ =μ0 shows that the equivalent widths decrease monotonically towards the poles, the limb and the terminator with the following characteristics: (i) the weakest lines exhibit the maximum change; (ii) the Ier component shows more change than the Iel component; (iii) the decrease towards the limb or the terminator is not as sharp as that towards the poles; (iv)Iel component shows more decrease towards the limb while Ier component shows more decrease towards the terminator; and (v) the relation W (μ,φ;μ0,φ0)= W (μ0,φ0;μ,φ) holds for the total intensity. These results are qualitatively in agreement with the observations of absorption bands in the spectra of Venus, Jupiter and Saturn
Photometric and spectroscopic study of R CMa
UBV light curves and spectrograms of R CMa obtained with the 48-inch telescope of Japal-Rangapur Observatory during 1980-82 have been used for deriving the eclipse and orbital elements as well as the absolute dimensions of the components. The primary is found to be a Main-Sequence F2V star of mass 1.52M⊙ and the secondary a subgiant star of spectral type G8 and mass 0.20M⊙ which fills its Roche lobe, in agreement with Kopal and Shapley (1956) results, Kopal (1959), or Sahade's (1963) results. From a consideration of the possible evolution of this system it is concluded that a large fraction of the original mass of the secondary is lost from the system. A study of the period changes indicates the possible presence of a third component of mass of about 0.5M⊙ which is most likely to be an M dwarf
Techniques for the study of singularities with applications to resolution of 2-dimensional schemes
We give an overview of invariants of algebraic singularities over perfect
fields. We then show how they lead to a synthetic proof of embedded resolution
of singularities of 2-dimensional schemes.Comment: 26 pages; minor changes have been adde
Prevalence of Advanced, Precancerous Colorectal Neoplasms in Black and White Populations: A Systematic Review and Meta-analysis
Background & Aims
Colorectal cancer (CRC) incidence and mortality are higher in black vs white populations. The reasons for these disparities are not clear, yet some guidelines recommend screening black persons for CRC starting at ages 40–45 years. We performed a systematic review and meta-analysis to compare the prevalence of advanced adenomas (AAs) and advanced, precancerous colorectal neoplasms (ACNs) between asymptomatic black and white screen-eligible adults.
Methods
We searched Ovid MEDLINE, PubMed, Embase, and the Cochrane Library to identify articles (published from 1946 through June 2017) that reported prevalence values of AA or ACN in average-risk black and white individuals undergoing screening colonoscopy. Two authors independently assessed study quality and risk for bias using a modified validated quality assessment instrument. Following the PRISMA guidelines, 2 authors independently abstracted descriptive and quantitative data from each study. We performed a random effects meta-analysis to determine risk differences and odds ratios (ORs).
Results
From 1653 articles, we identified 9 studies for analysis, comprising 302,128 individuals. Six of the 9 studies were of high methodological quality, had a low risk for bias, and were included in the meta-analysis. In these 9 studies, the overall prevalence values for AA and ACN did not differ significantly between back (6.57%) and white screened individuals (6.20%; OR, 1.03; 95% CI, 0.81–1.30). Among a subgroup of 5 studies, the prevalence of proximal AA and ACN was significantly higher in black (3.30%) than in white screened individuals (2.42%; OR, 1.20; 95% CI, 1.12–1.30). Excluding the largest study did not affect overall prevalence (OR, 0.99; CI, 0.73–1.34) but eliminated the difference in prevalence of proximal AA or ACN (OR, 1.48; 95% CI, 0.87–2.52).
Conclusions
In a meta-analysis, we found the overall prevalence of AA and ACN did not differ significantly between average-risk black and white persons, indicating that the age at which to begin CRC screening need not differ based on race
Peak reduction technique in commutative algebra
The "peak reduction" method is a powerful combinatorial technique with
applications in many different areas of mathematics as well as theoretical
computer science. It was introduced by Whitehead, a famous topologist and group
theorist, who used it to solve an important algorithmic problem concerning
automorphisms of a free group. Since then, this method was used to solve
numerous problems in group theory, topology, combinatorics, and probably in
some other areas as well.
In this paper, we give a survey of what seems to be the first applications of
the peak reduction technique in commutative algebra and affine algebraic
geometry.Comment: survey; 10 page
Log canonical thresholds of Del Pezzo Surfaces in characteristic p
The global log canonical threshold of each non-singular complex del Pezzo
surface was computed by Cheltsov. The proof used Koll\'ar-Shokurov's
connectedness principle and other results relying on vanishing theorems of
Kodaira type, not known to be true in finite characteristic.
We compute the global log canonical threshold of non-singular del Pezzo
surfaces over an algebraically closed field. We give algebraic proofs of
results previously known only in characteristic . Instead of using of the
connectedness principle we introduce a new technique based on a classification
of curves of low degree. As an application we conclude that non-singular del
Pezzo surfaces in finite characteristic of degree lower or equal than are
K-semistable.Comment: 21 pages. Thorough rewrite following referee's suggestions. To be
published in Manuscripta Mathematic
Capsulization of Weather Broadcasting System using Raspberry pi
Weather broadcasting plays an important role in human life, so the collection of information about the temporal dynamics of weather changes is very important. The fundamental aim of this project is to develop an embedded system and design a weather broadcast system which enables the broadcasting of weather parameters for different sector. Such a system contain pair of sensors like temperature, pressure and humidity, which is used to sense the atmospheric parameter. Block diagram consist of the Raspberry pi, DHT-22 and BMP-180 sensor which is used for analyze the atmospheric parameters. The data from the sensors are collected by the microcontroller and it stored in SD cardand LCD screen is used to display the result
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