scholarly journals The Statistical Analysis of Anisotropies

1977 ◽  
Vol 74 ◽  
pp. 75-81
Author(s):  
Adrian Webster
Keyword(s):  
Statistical Analysis ◽  
Statistical Method ◽  
Point Processes ◽  
Radio Sources ◽  
The Many ◽  
Celestial Sphere ◽  
Radio Survey

One of the many uses to which a radio survey may be put is an analysis of the distribution of the radio sources on the celestial sphere to find out whether they are bunched into clusters or lie in preferred regions of space. There are many methods of testing for clustering in point processes and since they are not all equally good this contribution is presented as a brief guide to what seem to be the best of them. The radio sources certainly do not show very strong clustering and may well be entirely unclustered so if a statistical method is to be useful it must be both powerful and flexible. A statistic is powerful in this context if it can efficiently distinguish a weakly clustered distribution of sources from an unclustered one, and it is flexible if it can be applied in a way which avoids mistaking defects in the survey for true peculiarities in the distribution of sources.

scholarly journals The JPL 1986–3 Extragalactic Reference Frame

1988 ◽  
Vol 133 ◽  
pp. 461-464
Author(s):  
O.J. Sovers ◽  
C.D. Edwards ◽  
C.S. Jacobs ◽  
G.E. Lanyi ◽  
R.N. Treuhaft
Keyword(s):  
Rotation Axis ◽  
Time Variability ◽  
Radio Sources ◽  
Dual Frequency ◽  
Deep Space Network ◽  
Space Network ◽  
Celestial Sphere ◽  
Almost All ◽  
Comparable Quality

Intercontinental dual-frequency radio interferometric measurements were carried out during 1978 to 1985 between NASA's Deep Space Network stations in California, Spain, and Australia. Analysis of 6800 pairs of delay and delay rate observations made during 51 sessions produced a catalog of positions of 106 extragalactic radio sources, fairly uniformly distributed over the celestial sphere between −45° and +85° declination. Almost all of the resulting source positions have formal uncertainties between 0.5 and 3 milliarcseconds, with their distributions peaking somewhat below 1 mas. Root-mean-square uncertainties are 2.1 and 2.0 mas for RA and declination, respectively. Evidence is found for a long-term drift of the Earth's rotation axis in inertial space, relative to the 1984 IAU precession and nutation models. Tests for time variability of positions of 32 frequently observed sources place limits at the 1 mas/yr level. Comparisons with independently determined source catalogs of comparable quality show differences of positions of common sources that amount to a few mas, and may indicate the level of systematic errors in VLBI source position measurements.

A Study on Statistical Analysis of Si-Wafer Polishing Process for the Optimum Polishing Condition

2008 ◽  
Vol 389-390 ◽  
pp. 493-497 ◽  
Author(s):  
Sung Chul Hwang ◽  
Jong Koo Won ◽  
Jung Taik Lee ◽  
Eun Sang Lee
Keyword(s):  
Surface Roughness ◽  
Statistical Analysis ◽  
Process Parameters ◽  
Wafer Surface ◽  
Wafer Polishing ◽  
Ultra Precision ◽  
Important Processing ◽  
The Many ◽  
Selection Of ◽  
Si Wafer

As the level of Si-wafer surface directly affects device line-width capability, process latitude, yield, and throughput in fabrication of microchips, it needs to have ultra precision surface and flatness. Polishing is one of the important processing having influence on the surface roughness in manufacturing of Si-wafers. The surface roughness in wafer polishing is mainly affected by the many process parameters. For decreasing the surface roughness, the control of polishing parameters is very important. In this paper, the optimum condition selection of ultra precision wafer polishing and the effect of polishing parameters on the surface roughness were evaluated by the statistical analysis of the process parameters.

scholarly journals Statistical analysis of cytogenetic data

2021 ◽  
Vol 28 ◽  
pp. 146-150
Author(s):  
L. A. Atramentova
Keyword(s):  
Data Structure ◽  
Statistical Analysis ◽  
Confidence Interval ◽  
Statistical Method ◽  
Confidence Intervals ◽  
Study Design ◽  
Cytogenetic Study ◽  
Data Set ◽  
Statistical Errors ◽  
Cytogenetic Data

Using the data obtained in a cytogenetic study as an example, we consider the typical errors that are made when performing statistical analysis. Widespread but flawed statistical analysis inevitably produces biased results and increases the likelihood of incorrect scientific conclusions. Errors occur due to not taking into account the study design and the structure of the analyzed data. The article shows how the numerical imbalance of the data set leads to a bias in the result. Using a dataset as an example, it explains how to balance the complex. It shows the advantage of presenting sample indicators with confidence intervals instead of statistical errors. Attention is drawn to the need to take into account the size of the analyzed shares when choosing a statistical method. It shows how the same data set can be analyzed in different ways depending on the purpose of the study. The algorithm of correct statistical analysis and the form of the tabular presentation of the results are described. Keywords: data structure, numerically unbalanced complex, confidence interval.

scholarly journals PENGARUH PENAMBAHAN TEPUNG DAUN KEMANGI (Acimum spp) DALAM PAKAN TERHADAP PERFORMANS AYAM BROILER

2017 ◽  
Vol 1 (3) ◽  
pp. 172
Author(s):  
Merry Simanjuntak
Keyword(s):  
Body Weight ◽  
Statistical Analysis ◽  
Body Weight Gain ◽  
Beta Carotene ◽  
Production Performance ◽  
Feed Consumption ◽  
Feed Conversion ◽  
Broiler Performance ◽  
Randomized Design ◽  
The Many

The Chicken broiler is a type of superior race chicken that has high genetic properties, especially in growth. The use of herbs as medicines in medicine is now starting to increase, which is evident from the many traditional drugs manufacturers on the market. One of the herbs that can be used as an antibiotic for livestock is basil (Ocimum sp). Basil contains beta-carotene (provitamin A), which supports the function of vision, improves antibody function (influences immune function), protein synthesis to support growth process and as the antioxidant (Adnyana and Firmansyah, 2006). The purpose of this study was to determine the effect of the addition of basil leaves flour up to 12% level against broiler performance. The experiment was carried out experimentally using a completely randomized design (CRD). The results of statistical analysis showed that the addition of basil meal powder into the feed did not affect to feed consumption between levels (P> 0). The result of the statistical analysis showed that the addition of basil meal powder into the feed had no effect (P> 0,05) to the increase in body weight. The result of the statistical analysis showed that the treatment with the addition of basil powder into the feed had no effect (P> 0,05) to feed conversion. The result of this research can be concluded that the addition of basil powder into feed up to 12% level did not give significantly different effect on production performance such as feed consumption, body weight gain and feed conversion of the broiler.

scholarly journals Monitoring source variability with the Fast All Sky Telescope

1991 ◽  
Vol 131 ◽  
pp. 445-448
Author(s):  
Kenneth J. Johnston ◽  
Ralph L. Fiedler ◽  
Richard S. Simon
Keyword(s):  
Interstellar Medium ◽  
Radio Wave ◽  
Wave Scattering ◽  
Study Time ◽  
Time Variability ◽  
Radio Sources ◽  
Limited Sample ◽  
Extragalactic Radio Sources ◽  
Design Goal ◽  
Celestial Sphere

AbstractThe proposed Fast All Sky Telescope (FAST) is an interferometer which is intended to monitor the northern four-fifths of the celestial sphere every two days at 8.1 GHz and daily at 2.7 GHz. The design goal is to have a rms sensitivity of 10 mJy/beam at both frequencies. The array is planned to comprise 20 3-meter diameter antennas with a maximum baseline of 0.7 km. FAST will provide a valuable database that may be used to study time variability in a sensitivity limited sample of radio sources. This will significantly impact on the understanding of active Galactic and extragalactic radio sources, as well as on the understanding of radio wave scattering in the interstellar medium.

Comparison of Tensile Testing Flow Stress to Orthogonal Plate Machining Flow Stress in FCC, BCC, and HCP Materials at Various Levels of Hardness Using a Videographic Quick Stop Device

2015 ◽  
Author(s):  
Lewis N. Payton ◽  
Wesley S. Hunko
Keyword(s):  
Statistical Analysis ◽  
Flow Stress ◽  
Tensile Testing ◽  
Metal Cutting ◽  
Force Plate ◽  
Orthogonal Machining ◽  
Hcp Materials ◽  
Load Frame ◽  
Material Conditions ◽  
The Many

Basic and advanced metal cutting research has been an ongoing effort since Cocquilhat’s early work directed towards measuring the work required to remove a given volume of material when drilling in the year 1851. Over the 150+ years since his experiments, one of the persistent issues in metal cutting has been how best to determine the flow stress in a metal undergoing cutting. In all the many models proposed since then, the flow stress of metal flowing in front of a cutting tool has not proven to be the same as the flow stress of metal undergoing a tensile pull. This paper examines the flow stress phenomenon using an improved Videographic Quick Stop equipment at Auburn University. The orthogonal machining plates and tensile specimens were all cut from the same stock. Tensile testing of the stock was performed immediately prior to the machining of the plates in a standard MTS load frame to allow actual metal cutting experiments to be performed and compared to actual load frame data from the same stock. Machining was conducted in a specially modified Cincinnati Horizontal Milling machine using an improved Videographic Quick Stop Device (VQSD) to capture the geometry of the cutting formation simultaneously with the forces in the X, Y and Z-axes using a standard Kistler force plate dynamometer. Utilizing the VQSD greatly increases the number of replicates available for statistical analysis by the metal cutting researcher. This allows for comprehensive multivariate analysis of the data with high confidence (> 95%) in the meaning of the results obtained, along with for powerful regression. The results of the data collection and statistical analysis are then used to populate the various historical models predicting the flow stress in metal cutting. The results indicate that one model is superior to all the other models in predicting the flow stress as predicted by the accompanying tensile test data. Further improvements in this model may lead to instantaneous tensile strength measurement when metal cutting with the need for load frames. This in turn would allow optimization of cutting conditions to match material conditions, resulting in a better product and longer-lived tools.

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