scholarly journals Correcting for Gaussian Aerial Smoothing

1955 ◽  
Vol 8 (1) ◽  
pp. 54 ◽  
Author(s):  
RN Bracewell
Keyword(s):  
Two Dimensional ◽  
The Mean ◽  
Standard Deviations ◽  
The Difference

Let a. two-dimensional survey with a Gaussian aerial beam establish values at intervals of standard deviations. Then the correction for aerial smoothing is simply calculated as the difference between the value to be corrected and the mean of the neighbouring four values.

Analyzing designed experiments: Should we report standard deviations or standard errors of the mean or standard errors of the difference or what?

2019 ◽  
Vol 56 (2) ◽  
pp. 312-319
Author(s):  
Marcin Kozak ◽  
Hans-Peter Piepho
Keyword(s):  
Statistical Methods ◽  
Standard Errors ◽  
Designed Experiments ◽  
Treatment Standard ◽  
The Mean ◽  
Standard Deviations ◽  
The Difference

AbstractANOVA, one of the most common statistical methods applied in agronomy, offers a variety of results we can report when analyzing designed experiments. The focus, of course, is on treatment means, but what should we report to characterize precision? Should we choose treatment standard deviations (SDs) or standard errors of the mean or standard errors of the difference (SEDs)? We discuss why treatment raw SDs should not be reported as the result of ANOVA, and point out that most of the time it is SEDs that should be provided.

Water Sensation During Passive Propulsion for Expert and Nonexpert Swimmers

2017 ◽  
Vol 124 (3) ◽  
pp. 662-673 ◽  
Author(s):  
Kenta Kusanagi ◽  
Daisuke Sato ◽  
Yasuhiro Hashimoto ◽  
Norimasa Yamada
Keyword(s):  
Skin Resistance ◽  
National Level ◽  
Absolute Error ◽  
Transformation Method ◽  
Two Dimensional ◽  
Eyes Closed ◽  
Video Recordings ◽  
Linear Transformation Method ◽  
The Mean ◽  
The Difference

This study determined whether expert swimmers, compared with nonexperts, have superior movement perception and physical sensations of propulsion in water. Expert (national level competitors, n = 10) and nonexpert (able to swim 50 m in > 3 styles, n = 10) swimmers estimated distance traveled in water with their eyes closed. Both groups indicated their subjective physical sensations in the water. For each of two trials, two-dimensional coordinates were obtained from video recordings using the two-dimensional direct linear transformation method for calculating changes in speed. The mean absolute error of the difference between the actual and estimated distance traveled in the water was significantly lower for expert swimmers (0.90 ± 0.71 meters) compared with nonexpert swimmers (3.85 ± 0.84 m). Expert swimmers described the sensation of propulsion in water in cutaneous terms as the “sense of flow” and sensation of “skin resistance.” Therefore, expert swimmers appear to have a superior sense of distance during their movement in the water compared with that of nonexpert swimmers. In addition, expert swimmers may have a better perception of movement in water. We propose that expert swimmers integrate sensations and proprioceptive senses, enabling them to better perceive and estimate distance moved through water.

Implementation of a Mixing Length Turbulence Formulation Into the Dynamic Wake Meandering Model

2012 ◽  
Vol 134 (2) ◽  
Author(s):  
Rolf-Erik Keck ◽  
Dick Veldkamp ◽  
Helge Aagaard Madsen ◽  
Gunner Larsen
Keyword(s):  
Cross Section ◽  
Turbulent Mixing ◽  
Eddy Viscosity ◽  
High Fidelity ◽  
Mixing Length ◽  
Two Dimensional ◽  
Wake Region ◽  
Mean Velocity ◽  
The Mean ◽  
The Difference

The work presented in this paper focuses on improving the description of wake evolution due to turbulent mixing in the dynamic wake meandering (DWM) model. From wake investigations performed with high-fidelity actuator line simulations carried out in ELLIPSYS3D, it is seen that the current DWM description, where the eddy viscosity is assumed to be constant in each cross-section of the wake, is insufficient. Instead, a two-dimensional eddy viscosity formulation is proposed to model the shear layer generated turbulence in the wake, based on the classical mixing length model. The performance of the modified DWM model is verified by comparing the mean wake velocity distribution with a set of ELLIPSYS3D actuator line calculations. The standard error (defined as the standard deviation of the difference between the mean velocity field of the DWM and the actuator line model), in the wake region extending from 3 to 12 diameters behind the rotor, is reduced by 27% by using the new eddy viscosity formulation.

A comparison of the classification systems of luminous stars in the northern Milky Way II and IV, for stars assigned two-dimensional spectral types from objective-prism plates

1966 ◽  
Vol 24 ◽  
pp. 70-73
Author(s):  
C. B. Stephenson
Keyword(s):  
Milky Way ◽  
Classification Systems ◽  
Two Dimensional ◽  
Joint Project ◽  
Ob Stars ◽  
Luminosity Class ◽  
Objective Prism ◽  
The Mean ◽  
The Difference ◽  
Hydrogen Lines

For some years a survey for early-type luminous stars in the northern Milky Way has been underway at the Warner and Swasey Observatory and the Hamburg Observatory, as a joint project by the two institutions (1). With the aid of ultraviolet-transmitting objective prisms (Schott UBK7 glass), it has been possible at both institutions to recognize OB stars at a dispersion of about 600Å/mm. Moreover, the appearance of the Balmer discontinuity at low dispersion affords a valuable aid to two-dimensional classification of stars of late B to late F types (2, 3). These two-dimensional classifications, which are based essentially upon the appearance of the continuum (especially the Balmer discontinuity), the hydrogen lines, the K line, and the G band, are assigned in the MK classification nomenclature since they are well correlated with classifications made by means of the real MK classification criteria. The quality of the correlation depends upon location in the HR diagram, but the random probable error appears to be upward of one MK luminosity class and about a quarter of a full letter division in temperature class, except that luminosity class IV is nowhere well distinguished from class V, and class Iab is not really well distinguished from Ia and Ib.The present Cleveland system of assigning two-dimensional spectral types to stars from ultraviolet-included objective-prism plates tends to assign lower luminosities than those of the LS II (–LS I?) system. This fact alone accounts for certainly most of the difference between the numbers of stars assigned two-dimensional spectral types in LS II and in LS IV. The origin of this systematic difference of over a luminosity class is not well explained, but the difference is hardly alarming. The numbers of OB stars in the two catalogues are quite comparable and this is consistent with the fact that no classification system difference for OB stars is known to exist between these two catalogues.Slit spectrograms so far available support the belief that LS IV agrees better in the mean with the MK system than does LS II, though LS IV may also be slightly overluminous in the mean. There is one factor always tending to confuse the transformation from this objective-prism system to MK spectral types: stars having abnormally strong Balmer discontinuities will usually be included in our catalogues with some kind of MK classification, While those with abnormally weak Balmer discontinuities will more often be excluded or assigned to the OB group. This problem is by no means so serious as to detract significantly from the desirability of making objective-prism surveys that pay special heed to the Balmer discontinuity.

Enumeration of Total Bacteria and Coliforms in Milk by Dry Rehydratable Film Methods: Collaborative Study

1986 ◽  
Vol 69 (3) ◽  
pp. 527-531 ◽  
Author(s):  
Roy E Ginn ◽  
Vernal S Packard ◽  
Terrance L Fox ◽  
◽  
E Arnold ◽  
...  
Keyword(s):  
Collaborative Study ◽  
Plate Count ◽  
Standard Methods ◽  
Standard Plate Count ◽  
Milk Samples ◽  
Standard Plate ◽  
The Mean ◽  
Standard Deviations ◽  
The Difference ◽  
Total Bacteria

Abstract Eleven laboratories participated in a collaborative study to compare the dry rehydratable film (Petrifilm® SM and Petrifilm® VRB) methods, respectively, to the standard plate count (SPC) and violet red bile agar (VRBA) standard methods for estimation of total bacteria and coliform counts in raw and homogenized pasteurized milk. Each laboratory analyzed 16 samples (8 different samples in blind duplicate) for total count by both the SPC and Petrifilm SM methods. A second set of 16 samples was analyzed by the VRBA and Petrifilm VRB methods. The repeatability standard deviations (the square root of the between-replicates variance) of the SPC, Petrifilm SM, VRBA, and Petrifilm VRB methods were 0.0S104, 0.0444, 0.14606, and 0.13806, respectively; the reproducibility standard deviations were 0.7197, C.06380, 0.15326, and 0.13806, respectively. The difference between the mean Iog10 SPC and the mean logio Petrifilm SM results was 0.027. For the VRBA and Petrifilm VRB methods, the mean log10 difference was 0.013. These results generally indicate the suitability of the dry rehydratable film methods as alternatives to the SPC and VRBA methods for milk samples. The methods have been adopted official first action.

scholarly journals Wake Decay: Effect of Freestream Swirl

1997 ◽  
Author(s):  
J. M. Brookfield ◽  
I. A. Waitz ◽  
J. Sell
Keyword(s):  
Three Dimensional ◽  
Navier Stokes ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Mixing Rate ◽  
Rotating Blade ◽  
Blade Row ◽  
The Mean ◽  
The Difference ◽  
Fan Blade

A study of the effects of freestream swirl on the decay characteristics of wakes shed from a rotating blade row is presented. The freestream swirl behind the rotor causes the wakes to skew tangentially, stretching the wakes as they are convected from the rotor to the stator. The effect of stretching on wake decay is illustrated using a simplified two-dimensional model. The model is described and the results are compared to 1) measurements from a two-dimensional cascade facility where no stretching or skewing of the wakes occurs, 2) solutions obtained using a three-dimensional, Reynolds-averaged Navier-Stokes solver, and 3) experimental wake measurements taken behind a low hub-to-tip ratio fan. For typical fan geometries with hub-to-tip ratios of approximately 0.5 and rotor-stator spacings of one to two rotor chord lengths, the wake can be stretched by over 50 percent. The stretching increases the mixing rate which leads to a reduction in the mean wake velocity deficit of approximately thirty percent and a widening of the wake of about fifteen percent. These effects account for much of the difference seen between cascade wake measurements and those taken behind rotating fan blade rows. It is therefore important to include such effects when using cascade data for prediction of fluid mechanic, acoustic, or structural phenomena associated with fan wakes. Finally, the study also suggests a potential for small (< 3 dB) reductions in wake-stator interaction noise through tailoring the fan loading distribution to produce particular span wise wake decay characteristics.

Gender differences in suicide ideation among college students in Kuwait

2016 ◽  
Vol 33 (S1) ◽  
pp. S597-S597
Author(s):  
R. Alsalman
Keyword(s):  
College Students ◽  
Gender Differences ◽  
Suicide Ideation ◽  
Descriptive Statistics ◽  
Self Report ◽  
Clinical Population ◽  
The Mean ◽  
Standard Deviations ◽  
The Difference ◽  
Competing Interest

IntroductionThe Beck Scale for Suicide ideation (BSS) has consistently been regarded as a strong tool for measuring cognitive and somatic aspects of suicide ideation symptomatology in both clinical and non-clinical population. There is no study until this date that examines the BSS within Kuwaiti College students.ObjectiveThe present study aims at identifying impact of gender (male/female) on suicide ideation.MethodsThe sample was consisted of (584) undergraduates students (284 of males and 300 females). The study applies Beck Scale for Suicide ideation (BSS) and suicide Ideation Questionnaire (SIQ).ResultsTable 1 descriptive statistics for two standardized self-report measures means and standard deviations for these measures were within the expected ranges for college samples. The mean (BSS) score was 5.2 for males and 7.0 for females. The mean (SIQ) score was 11.3 for males and 13.7 for females.ConclusionBSS revealed significant gender differences in score indicated that females obtained higher scores than males on suicide Ideation although the magnitude of the difference was small.Table not available.Disclosure of interestThe author has not supplied his declaration of competing interest.

scholarly journals Secularism as Related to Gender and Religion

2015 ◽  
Vol 2 (3) ◽  
Author(s):  
Dr. Shashi Kala Singh ◽  
Mrs. Pushpa Singh
Keyword(s):  
Female Student ◽  
Economic Status ◽  
Male Student ◽  
School Students ◽  
Socio Economic Status ◽  
The Mean ◽  
Standard Deviations ◽  
The Difference ◽  
Age Range ◽  
Scale Data

The aim of the present study was to examine the gender and religion difference in secularism. Participants were 100 school students belong to Ranchi town (50 boys& 50 girls) of age range 13 to 16 years. All of these belong to middle socio-economic status. Respondents were given secularism scale. Data was analyzed by using means, standard deviations and “t”. The mean of male student was 31.53and female student was 29.97. The difference between the means was insignificant. Boys and girls showed similar level of secularism.Christian group showed significantly higher level of secularism than Muslim group.

scholarly journals Meta-analysis of the variance ratio

2017 ◽  
Author(s):  
Nicolas Traut
Keyword(s):  
Standard Deviation ◽  
Meta Analysis ◽  
Mean Difference ◽  
Variance Ratio ◽  
Mean Values ◽  
Variance Ratios ◽  
The Mean ◽  
Standard Deviations ◽  
The Difference ◽  
Fisher’S Ratio

IntroductionThe most commonly used effect size when using meta-analysis to compare a measurement of interest in two different populations is the standardised mean difference. This is the mean difference of the measurement divided by the pooled standard deviation in the two groups. The standard deviation is usually supposed to be the same for both groups, although this assumption is often made without any particular evidence. It is possible, however, that the difference of the measurement in the two populations resides precisely in their standard deviations. This could be the case, for example, if a population of patients exhibited more “abnormal” values than a control population – both large and small – even if the mean values were the same. Fisher’s test of equality of variance is designed to compare standard deviations. A variance ratio is a Fisher’s ratio and Fisher distribution can be used to give confidence intervals to the estimate for one study. However, confidence interval for one study can be very wide if the study does not contain enough subjects. Here we present an approach to combine variance ratios of different studies in a meta-analytic way which produces more robust estimates under these circumstances.

A one-dimensional self-gravitating stellar gas

1966 ◽  
Vol 25 ◽  
pp. 46-48 ◽  
Author(s):  
M. Lecar
Keyword(s):  
Gravitational Field ◽  
Phase Space ◽  
Motion Picture ◽  
Space Distribution ◽  
Two Dimensional ◽  
One Dimensional ◽  
Phase Space Distribution ◽  
Dimensional Phase Space ◽  
The Mean

“Dynamical mixing”, i.e. relaxation of a stellar phase space distribution through interaction with the mean gravitational field, is numerically investigated for a one-dimensional self-gravitating stellar gas. Qualitative results are presented in the form of a motion picture of the flow of phase points (representing homogeneous slabs of stars) in two-dimensional phase space.

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