scholarly journals Nadir Correction of AIRS Radiances

2010 ◽  
Vol 27 (3) ◽  
pp. 470-480 ◽  
Author(s):  
Chee-Kiat Teo ◽  
Tieh-Yong Koh
Keyword(s):  
Water Vapor ◽  
Standard Deviation ◽  
The Other ◽  
Mean Square ◽  
Atmospheric Infrared Sounder ◽  
Limb Effect ◽  
Atmospheric Window ◽  
The Mean ◽  
Optimal Set ◽  
Atmospheric Windows

Abstract A statistical method to correct for the limb effect in off-nadir Atmospheric Infrared Sounder (AIRS) channel radiances is described, using the channel radiance itself and principal components (PCs) of the other channel radiances to account for the multicollinearity. A method of selecting an optimal set of predictors is proposed and demonstrated for one- and two-PC predictors. Validation results with a subset of AIRS channels in the spectral region 649–2664 cm−1 show that the mean nadir-corrected brightness temperature (BT) is largely independent of scan angle. More than 66% of the channels have a root-mean-square (rms) bias less than 0.10 K after nadir correction. Limb effect on the standard deviation (SD) of BT is discernible at larger scan angles, mainly for the atmospheric windows and the water vapor channels around 6.7 μm. After nadir correction, nearly all atmospheric window channels unaffected by solar glint and more than 76% of water vapor channels examined have BT SDs brought closer to nadir values. For the window channels affected by solar glint (wavenumber > 2490 cm−1), BT SDs at the scan angles with the strongest impact from solar reflection were improved on average by more than 0.6 K after nadir correction.

scholarly journals An alternative to the rejection of observations

1932 ◽  
Vol 137 (831) ◽  
pp. 78-87 ◽  
Keyword(s):  
Standard Deviation ◽  
Continuous Function ◽  
Large Deviations ◽  
Opposite Direction ◽  
Standard Error ◽  
The Other ◽  
Cause Of Error ◽  
The Mean ◽  
Normal Law ◽  
Usual Rule

1. It is widely felt that any method of rejecting observations with large deviations from the mean is open to some suspicion. Suppose that by some criterion, such as Peirce’s and Chauvenet’s, we decide to reject observations with deviations greater than 4 σ, where σ is the standard error, computed from the standard deviation by the usual rule; then we reject an observation deviating by 4·5 σ, and thereby alter the mean by about 4·5 σ/ n , where n is the number of observations, and at the same time we reduce the computed standard error. This may lead to the rejection of another observation deviating from the original mean by less than 4 σ, and if the process is repeated the mean may be shifted so much as to lead to doubt as to whether it is really sufficiently representative of the observations. In many cases, where we suspect that some abnormal cause has affected a fraction of the observations, there is a legitimate doubt as to whether it has affected a particular observation. Suppose that we have 50 observations. Then there is an even chance, according to the normal law, of a deviation exceeding 2·33 σ. But a deviation of 3 σ or more is not impossible, and if we make a mistake in rejecting it the mean of the remainder is not the most probable value. On the other hand, an observation deviating by only 2 σ may be affected by an abnormal cause of error, and then we should err in retaining it, even though no existing rule will instruct us to reject such an observation. It seems clear that the probability that a given observation has been affected by an abnormal cause of error is a continuous function of the deviation; it is never certain or impossible that it has been so affected, and a process that completely rejects certain observations, while retaining with full weight others with comparable deviations, possibly in the opposite direction, is unsatisfactory in principle.

Effect on Polymer Chain Structure Caused by the Molar Fraction of 4-Hydroxybutyrate in Poly(3-hydroxybutyrate- co -4-hydroxybutyrate)

2012 ◽  
Vol 602-604 ◽  
pp. 776-780
Author(s):  
Zhi Qiang Li ◽  
Mei Li ◽  
Wei Jia Fan
Keyword(s):  
Molecular Weight ◽  
Intrinsic Viscosity ◽  
Polymer Chain ◽  
Molar Fraction ◽  
Chain Structure ◽  
The Other ◽  
Mean Square ◽  
Polarizing Microscope ◽  
Other Hand ◽  
The Mean

Poly(3-hydroxybutyrate-co-4-hydroxybutyrate)copolymer [P(3HB-co-4HB)] is a kind of biodegradable high molecular polymer produced by bioaccumulation. Because of the good biodegradability and biocompatibility, P(3HB-co-4HB)s have attracted wide attention . At first, the intrinsic viscosity[η] in good solvent of P(3HB-co-4HB) s with varying contents of 4HB was investigated in different temperature. Second, observed the changes of crystallization gathered state caused by the varying contents of 4HB by polarizing microscope. The results show that to the P(3HB-co-4HB)s in same molecular weight, the intrinsic viscosity[η] in good solvent barely changes when the mole fractions of 4HB increase. On the other hand, the mean square end to end distances[0] of macromolecular flexible chains increase with the mole fractions of 4HB. At the same time, the states of aggregation change from spherulites to dendrites. In this investigation, we discuss the reasons of the differences in depth.

scholarly journals Study of Aerosol Influence on Nighttime Land Surface Temperature Retrieval Based on Two Methods

2015 ◽  
Vol 2015 ◽  
pp. 1-16 ◽  
Author(s):  
Caixia Gao ◽  
Enyu Zhao ◽  
Chuanrong Li ◽  
Yonggang Qian ◽  
Lingling Ma ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Water Vapor ◽  
Standard Deviation ◽  
Land Surface ◽  
Simulated Data ◽  
Mean Square ◽  
Surface Emissivity ◽  
Land Surface Emissivity ◽  
Instrument Noise ◽  
Temperature Retrieval

The aim of this study is to evaluate the aerosol influence on LST retrieval with two algorithms (split-window (SW) method and a four-channel based method) using simulated data under typical conditions. The results show that the root mean square error (RMSE) decreases to approximately 2.3 K for SW method and 1.5 K for four channel based method when VZA = 60° and visibility = 3 km; an RMSE would be increased by approximately 1.0 K when visibility varies from 3 km to 23 km. Moreover, a detailed sensitivity analysis under a visibility of 3 km and 23 km is performed in terms of uncertainties of land surface emissivity (LSE), water vapor content (WVC), and instrument noise, respectively. It is noted that the four-channel based method is more sensitive to LSE than SW method, especially for dry atmosphere; LST error caused by a WVC uncertainty of 20% is within 1.5 K for SW method and within 0.8 K for four-channel based method; the instrument noise would introduce LST error with a maximum standard deviation of 0.5 K and 0.04 K for the four-channel based method and SW method, respectively.

scholarly journals Nature versus Nurture in Shallow Convection

2010 ◽  
Vol 67 (5) ◽  
pp. 1655-1666 ◽  
Author(s):  
David M. Romps ◽  
Zhiming Kuang
Keyword(s):  
Standard Deviation ◽  
The Other ◽  
Cloud Base ◽  
Shallow Convection ◽  
Eddy Simulation ◽  
Cloud Properties ◽  
Nature Versus Nurture ◽  
Large Eddy ◽  
The Mean ◽  
Single Set

Abstract Tracers are used in a large-eddy simulation of shallow convection to show that stochastic entrainment (and not cloud-base properties) determines the fate of convecting parcels. The tracers are used to diagnose the correlations between a parcel’s state above the cloud base and both the parcel’s state at the cloud base and its entrainment history. The correlation with the cloud-base state goes to zero a few hundred meters above the cloud base. On the other hand, correlations between a parcel’s state and its net entrainment are large. Evidence is found that the entrainment events may be described as a stochastic Poisson process. A parcel model is constructed with stochastic entrainment that is able to replicate the mean and standard deviation of cloud properties. Turning off cloud-base variability has little effect on the results, which suggests that stochastic mass-flux models may be initialized with a single set of properties. The success of the stochastic parcel model suggests that it holds promise as the framework for a convective parameterization.

scholarly journals Catalogue of Clusters that are Members of Superclusters

1983 ◽  
Vol 104 ◽  
pp. 185-186
Author(s):  
M. Kalinkov ◽  
K. Stavrev ◽  
I. Kuneva
Keyword(s):  
Standard Deviation ◽  
Correlation Coefficient ◽  
The Other ◽  
Clusters Of Galaxies ◽  
Number Of Clusters ◽  
Abell Clusters ◽  
The Mean ◽  
Abell Cluster ◽  
Image Position

An attempt is made to establish the membership of Abell clusters in superclusters of galaxies. The relation is used to calibrate the distances to the clusters of galaxies with two redshift estimates. One is m10, the magnitude of the ten-ranked galaxy, and the other is the “mean population,” P, defined by: where p = 40, 65, 105 … galaxies for richness groups 0, 1, 2 …, and r is the apparent radius in degrees given by: The first iteration for redshift, z1, is obtained from m10 alone: The standard deviation for Eq. (1) is 0.105, the number of clusters with known velocities is 342 and the correlation coefficient between observed and fitted values is 0.921. With zi from Eq. (1), we define Cartesian galactic coordinates Xi = Rih−1 cosBi cosLi, Yi = Rih−1 cosBi sinLi, Zi = Rih−1 sinBi for each Abell cluster, i = 1, …, 2712, where Ri is the distance to the cluster (Mpc), and Ho = 100 h km s−1 Mpc−1.

Rapid Rhino versus Merocel nasal packs in septal surgery

2011 ◽  
Vol 125 (12) ◽  
pp. 1244-1246 ◽  
Author(s):  
A Hesham ◽  
A Ghali
Keyword(s):  
Standard Deviation ◽  
Pain Score ◽  
Visual Analogue Score ◽  
Nasal Packing ◽  
The Other ◽  
Septal Surgery ◽  
Patient Tolerance ◽  
Operative Complications ◽  
The Mean

AbstractObjective:To compare Rapid Rhino and Merocel packs for nasal packing after septoplasty, in terms of patient tolerance (both with the pack in place and during removal) and post-operative complications.Materials and methods:Thirty patients (aged 18–40 years) scheduled for septoplasty were included. Following surgery, one nasal cavity was packed with Rapid Rhino and the other one with Merocel. Patients were asked to record pain levels on a visual analogue score, on both sides, with the packs in situ and during their removal the next day. After pack removal, bleeding was compared on both sides.Results:The mean ± standard deviation pain score for the Rapid Rhino pack in situ (4.17 ± 1.78) was less than that for the Merocel pack (4.73 ± 2.05), but not significantly so (p = 0.314). The mean pain score for Rapid Rhino pack removal (4.13 ± 1.76) was significantly less that that for Merocel (6.90 ± 1.67; p = 0.001). Bleeding after pack removal was significantly less for the Rapid Rhino sides compared with the Merocel sides (p <0.05).Conclusion:Rapid Rhino nasal packs are less painful and cause less bleeding, compared with Merocel packs, with no side effects. Thus, their use for nasal packing after septal surgery is recommended.

scholarly journals Prevalencia de síndrome de burnout en los estudiantes de la Carrera de Enfermería de la Universidad Central del Ecuador

2020 ◽  
Vol 4 (8) ◽  
pp. 38-54
Author(s):  
Luzmila De Jesús Carvajal Andrade ◽  
◽  
Belén del Rocío Logacho Villacís ◽  
Ramiro Rogelio Rojas Jaramillo ◽  
◽  
...  
Keyword(s):  
Standard Deviation ◽  
Confidence Interval ◽  
Key Words ◽  
Nursing School ◽  
The Other ◽  
Burnout Syndrome ◽  
Information Analysis ◽  
Academic Burnout ◽  
Upper Limit ◽  
The Mean

This research has been conducted in order to determine the Prevalence of the burnout syndrome among students from third to eighth semester who are attending the Nursing School. It was a prevalence study; the data were collected using the survey’s technique, in a questionnaire divided in five sections applied to 172 students. The information analysis was calculated using the Mean method and the Standard Deviation for the Academic burnout, while for the Labor burnout it was utilized the punctuation of: high, medium and low scales. The outcome results showed that the prevalence of the burnout Syndrome in both academic and labor was low. The 2.3 % of students had the Academic burnout, (Confidence interval: 95%, lower limit: 0.44% and upper limit: 4.21%) with a probability of 3.52%, on the other hand the Labor burnout was of 4% among students in the shifting internship, with a probability of 1.22%. Key words: Syndrome burnout, Stress, nursing.

scholarly journals Enhanced CORDIC Based Rotator Design for Sinusoidal Transforms

2020 ◽  
Vol 9 (3) ◽  
pp. 1001-1004
Keyword(s):  
Fourier Transform ◽  
Frequency Domain ◽  
Discrete Fourier Transform ◽  
Mean Square Error ◽  
Time Domain ◽  
Basis Function ◽  
The Other ◽  
Mean Square ◽  
Circular Rotation ◽  
The Mean

Transforms play an important role in conversion of information from one domain to the other. To be more specific transforms like Discrete Fourier transform (DFT) and Discrete Cosine transform (DCT) helps us to migrate from one time domain to frequency domain based on the basis function selected. The basis function of the every sinusoidal transform carries out a circular rotation to convert information from one domain to the other. There are applications related to communication which requires this rotation into the hyperbolic trajectory as well. Multiplierless algorithm like CORDIC improves the latency of the transforms by eliminating the number of multipliers in the basis function. In this paper we have designed and implemented enhanced version of CORDIC based Rotator design. The Enhanced version is simulated for order 1 to order 36 to emphasize on the results of the proposed algorithm. Results shows that the enhanced CORDIC rotator design surpasses the Mean square error after the order 18 compared to standard CORDIC. Unified CORDIC also can be implemented using the said algorithm to implement different three trajectories.

scholarly journals On The Estimation of Means and Variances In The Case Of Unequal Components

1975 ◽  
Vol 8 (3) ◽  
pp. 323-335 ◽  
Author(s):  
Esa Hovinen
Keyword(s):  
Standard Deviation ◽  
The Other ◽  
Insurance Companies ◽  
Loss Ratio ◽  
Weighted Mean ◽  
The Mean ◽  
Image Position ◽  
Statistical Work ◽  
Better Than

In practical statistical work one frequently meets certain problems. For instance, we may have the following data about loss ratios in certain insurance companies and corresponding, numbers of insurance in force:I assume further that we have no reason to believe that the companies, their loss ratios and their structure of insurances in force differ in any other way than by the size of companies. The problem is how to get quick estimates of mean losses and their variances in different companies?A straitforward way to estimate the mean loss ratio would be to compute the usual mean of numbers pi, (Σpi/6) = 14; its standard deviation is 6,5. As this procedure of the “first statistician” seems to be too simple and naive, a “more cautious” statistician would compute the weighted mean loss ratioThe “more cautious” statistician would arque that his result is much better than the other result 14. But what would be the variance of the estimate 7,1, and what is the variance in the different companies?

Performance of the short-period geophones of the IRIS/PASSCAL Array

1991 ◽  
Vol 81 (1) ◽  
pp. 232-242 ◽  
Author(s):  
William Menke ◽  
Larry Shengold ◽  
Guo Hongsheng ◽  
Hu Ge ◽  
Arthur Lerner-Lam
Keyword(s):  
Standard Deviation ◽  
Voltage Sensitivity ◽  
Mean Square ◽  
Negative Mass ◽  
Natural Period ◽  
Loma Prieta Earthquake ◽  
Short Period ◽  
Mass Displacement ◽  
The Mean ◽  
Cross Axis

Abstract We calibrated 64 Mark Products L22-D short-period geophones of the IRIS/PASSCAL Array using a mass-displacement test. The mean natural frequency of the 192 components was 2.1 Hz (slightly larger than the nominal value of 2 Hz) with a standard deviation of about ±0.15 Hz. The standard deviation of the voltage sensitivity is about ±5 per cent. Variability of both sensitivity and natural period are within the manufacturer's published specifications. Three types of nonlinearities were noted: a 5 per cent difference in parameters determined by positive and negative mass-displacements, possibly due to a nonlinear spring (observed on more than 90 per cent of the 192 components tested); apparent cross-axis errors in wide (1 to 2 Hz) bands near 10 Hz; and spurious resonance peaks at frequencies between 22 and 29 Hz (observed on about 20 per cent of the components). Array equalization of seismograms from the Loma Prieta earthquake aftershock survey indicate that the root mean square misfit between two seismograms recorded by different geophones at the same site can be reduced from ∼10 per cent to ∼5 per cent by application of the calibration results.

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