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.

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 The evaluation of effectiveness of the device "Coilbox" on the mill 1680

2018 ◽  
pp. 300-308
Author(s):  
N.I. Podobedov ◽  
V.V. Verenev ◽  
V.V. Korennoi
Keyword(s):  
Comparative Analysis ◽  
Standard Deviation ◽  
Polyurethane Foam ◽  
Dynamic Loads ◽  
Dynamic Factor ◽  
Mean Square ◽  
Mean Square Deviation ◽  
The Mean ◽  
The Moment ◽  
Hot Rolled

The aim of the work is to conduct a comparative analysis of the results of rolling hot-rolled strips in the finishing group of mill stands of 1680 strips with and without the use of an intermediate rewinding device (PUF). A comparative analysis of the results of measurements of the moment and longitudinal thickness during rolling in the finishing group of stands is given. Given the distribution of torque in the cages along the length of the strip. It is shown that the mean square deviation of the moment is noticeably less than the rolling time without PUF. The level of dynamic loads and the dynamic factor of the moment of elastic force during the rolling of bands with polyurethane foam and without polyurethane foam practically did not change. It is shown that when rolling without PUF on the finished strip there remains a trace of the temperature wedge in the form of a wedge of thickness. When rolling with PUF, the thickness of the strip along its length becomes more uniform. When rolling without PUF, a trace of a wedge of thickness in the form of a wedge remains on the finished strip. When rolling with PUF, the thickness of the strip along its length becomes more uniform. In general, a comparison of the average moment along the stripes, the standard deviation, the coefficient of variation of the moment and the deviation of the thickness shows the advantages of rolling with PUF.

Peak Accelerations From the 17 October 1989 Loma Prieta Earthquake

1989 ◽  
Vol 60 (4) ◽  
pp. 151-166 ◽  
Author(s):  
David M. Boore ◽  
Linda Seekins ◽  
William B. Joyner
Keyword(s):  
Standard Deviation ◽  
Main Shock ◽  
Free Field ◽  
Strong Motion ◽  
Loma Prieta Earthquake ◽  
The Mean ◽  
Correction For Attenuation ◽  
Loma Prieta ◽  
Predicted Values

Abstract Peak accelerations of the Loma Prieta main shock have been tabulated from instruments maintained by a number of organizations. We have analyzed a subset of 86 records from nominally free-field sites, which have been subdivided into rock, alluvium, and bay-mud categories according to data available in various reports. After correction for attenuation, the peak accelerations on rock, alluvium, and bay-mud sites are factors of 1.6, 1.8, and 4.5 larger, on the average, than Joyner and Boore’s (1988) predicted values for a M= 6.9 earthquake. The mean motions for the rock and alluvium sites are somewhat greater than one standard deviation away from the predicted value, but the mean acceleration from the bay-mud sites is well outside the range expected from analyses of data from previous earthquakes from rock and alluvium sites. Large amplitudes of motions on bay-mud sites relative to rock sites (a factor of 2.8 for the average of the recordings of the Loma Prieta main shock) has been found previously from recordings of distant earthquakes and explosions, but the Loma Prieta earthquake provided the first opportunity to study the relative amplitudes from strong-motion recordings.

scholarly journals On the improbability of a random distribution of the Stars in Space

1910 ◽  
Vol 84 (571) ◽  
pp. 369-371
Keyword(s):  
Standard Deviation ◽  
Uniform Distribution ◽  
Random Distribution ◽  
Square Root ◽  
Mean Square ◽  
Mean Square Deviation ◽  
The Mean

In a recent paper Prof. Karl Pearson obtains the following results:— (i) If P = log 10 π when π denotes the parallax of a star, and σ P be the standard deviation, or square root of the mean square deviation of a series of values of P from the mean; then, for a uniform distribution of stars in space, 25 σ P 2 = 0·5240. (ii) If ͞m be the mean magnitude of all stars down to and including those of magnitude m 0 , then ͞m = m 0 — 0·7238, and σ m 2 = 0·5240.

the effects of resonance with Jupiter in the system of short-period comets

1974 ◽  
Vol 22 ◽  
pp. 193-203
Author(s):  
L̆ubor Kresák
Keyword(s):  
Structural Effects ◽  
Order Resonance ◽  
Mean Motion ◽  
Short Period ◽  
The Mean ◽  
Compound Effect ◽  
Low Order

AbstractStructural effects of the resonance with the mean motion of Jupiter on the system of short-period comets are discussed. The distribution of mean motions, determined from sets of consecutive perihelion passages of all known periodic comets, reveals a number of gaps associated with low-order resonance; most pronounced are those corresponding to the simplest commensurabilities of 5/2, 2/1, 5/3, 3/2, 1/1 and 1/2. The formation of the gaps is explained by a compound effect of five possible types of behaviour of the comets set into an approximate resonance, ranging from quick passages through the gap to temporary librations avoiding closer approaches to Jupiter. In addition to the comets of almost asteroidal appearance, librating with small amplitudes around the lower resonance ratios (Marsden, 1970b), there is an interesting group of faint diffuse comets librating in characteristic periods of about 200 years, with large amplitudes of about±8% in μ and almost±180° in σ, around the 2/1 resonance gap. This transient type of motion appears to be nearly as frequent as a circulating motion with period of revolution of less than one half that of Jupiter. The temporary members of this group are characteristic not only by their appearance but also by rather peculiar discovery conditions.

The Bordeaux Automatic Meridian Circle

1978 ◽  
Vol 48 ◽  
pp. 227-228
Author(s):  
Y. Requième
Keyword(s):  
Mean Square Error ◽  
Mean Square ◽  
Meridian Circle ◽  
The Mean ◽  
Full Automation

In spite of important delays in the initial planning, the full automation of the Bordeaux meridian circle is progressing well and will be ready for regular observations by the middle of the next year. It is expected that the mean square error for one observation will be about ±0.”10 in the two coordinates for declinations up to 87°.

At Least One Standard Deviation Above the Mean

1969 ◽  
Vol 14 (9) ◽  
pp. 470-471
Author(s):  
M. DAVID MERRILL
Keyword(s):  
Standard Deviation ◽  
The Mean

The mean-square generalized delayed decision feedback sequence detector

2003 ◽  
Vol 14 (3) ◽  
pp. 265-268 ◽  
Author(s):  
Maurizio Magarini ◽  
Arnaldo Spalvieri ◽  
Guido Tartara
Keyword(s):  
Decision Feedback ◽  
Mean Square ◽  
The Mean

The Estimation of Blood Platelet Survival

1972 ◽  
Vol 28 (03) ◽  
pp. 447-456 ◽  
Author(s):  
E. A Murphy ◽  
M. E Francis ◽  
J. F Mustard
Keyword(s):  
Standard Deviation ◽  
Least Squares ◽  
Experimental Error ◽  
Blood Platelet ◽  
Least Squares Estimation ◽  
Systematic Relationship ◽  
Platelet Survival ◽  
The Mean ◽  
Normally Distributed

SummaryThe characteristics of experimental error in measurement of platelet radioactivity have been explored by blind replicate determinations on specimens taken on several days on each of three Walker hounds.Analysis suggests that it is not unreasonable to suppose that error for each sample is normally distributed ; and while there is evidence that the variance is heterogeneous, no systematic relationship has been discovered between the mean and the standard deviation of the determinations on individual samples. Thus, since it would be impracticable for investigators to do replicate determinations as a routine, no improvement over simple unweighted least squares estimation on untransformed data suggests itself.

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