scholarly journals Quantifying Repeatability Reproducibility Sources of Error and Capacity of a Measurement: Demonstrated Using Laboratory Soil Plasticity Tests

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Cheng Li ◽  
Jeramy C. Ashlock ◽  
Xuhao Wang
Keyword(s):  
Linear Shrinkage ◽  
Atterberg Limits ◽  
Error Sources ◽  
Soil Plasticity ◽  
Sources Of Error ◽  
Single Operator ◽  
Measured Characteristic ◽  
Thread Rolling ◽  
Testing Standards ◽  
Different Sources

The repeatability, reproducibility, and sources of error inherent in a given measurement are important considerations for potential users. To quantify errors arising from a single operator or multiple laboratories, most testing standards uses a one-way analysis of variance- (ANOVA-) based method, which utilizes a simple standard deviation across all measurements. However, this method does not allow users to quantify the sources of error and capacity (i.e., the precision to tolerance ratio). In this study, an innovative two-way ANOVA-based analysis method is selected to quantify the relative contributions of different sources of error and determine whether a measurement can be used to check conformance of a measured characteristic to engineering specifications. In this study, the standardized Atterberg limits tests, fall-cone device Atterberg limits tests, and bar linear shrinkage tests widely used for determining the soil plasticity were selected for evaluation and demonstration. Comparisons between results of the various testing methods are presented, and the error sources contributing to the overall variations between tests are discussed. Based on the findings of this study, the authors suggest use of two-way ANOVA-based R&R analysis to quantify the sources of measurement error and capacity and also recommend using the fall cone device and ASTM standardized thread rolling device for determining liquid and plastic limits of soils, respectively.

The calculation of deflexions of the vertical from gravity anomalies

1950 ◽  
Vol 204 (1078) ◽  
pp. 374-395 ◽  
Keyword(s):  
Gravity Data ◽  
Gravity Anomalies ◽  
Sources Of Error ◽  
Free Air ◽  
Gravity Measurements ◽  
Standard Deviations ◽  
The Difference ◽  
Different Sources

The theory of the application of gravity measurements to geodetic calculations is discussed, and the errors involved in calculating deflexions of the vertical are estimated. If the gravity data are given as free air anomalies from Jeffreys’s (1948) formula, so thdt the second and third harmonics of gravity are assumed known, the orders of magnitude of the standard deviations of the different sources of error are the following: Single deflexion: neglect of gravity outside 20° 1" Difference of deflexions: neglect of gravity outside 5° 0"·5 Calculation of effects of gravity from 0º·05 to 5° 0"·1 Calculation of effects of gravity within 0º·05 between 0"·1 and 0"·5 Estimates of the deflexions are made for Greenwich, Herstmonceux, Southampton and Bayeux, and the difference between Greenwich and Southampton is compared with the astronomical and geodetic amplitudes.

Influence of different sources of error on estimated kinetics parameters for a second-order reaction

2004 ◽  
Vol 71 (1) ◽  
pp. 47-60 ◽  
Author(s):  
Antonio R. Carvalho ◽  
Richard G. Brereton ◽  
Tom J. Thurston ◽  
Richard E.A. Escott
Keyword(s):  
Order Reaction ◽  
Second Order ◽  
Second Order Reaction ◽  
Kinetics Parameters ◽  
Sources Of Error ◽  
Different Sources

Generalizability theory

2015 ◽  
Author(s):  
David L. Streiner ◽  
Geoffrey R. Norman ◽  
John Cairney
Keyword(s):  
Basic Concept ◽  
Generalizability Theory ◽  
Optimal Strategies ◽  
Relative Magnitude ◽  
Reliability Theory ◽  
Fixed Number ◽  
Multiple Sources ◽  
Detailed Review ◽  
Sources Of Error ◽  
Different Sources

This chapter is a detailed review of generalizability theory (G theory), an extension of classical reliability theory originally devised by Cronbach. The basic concept is that any measurement contains multiple sources of error, and through the use of G theory these various sources can be calculated in a single study. This permits the researcher to examine the relative magnitude of different sources of error and the relation among them. The power of the method rests in its ability to use these estimates to devise optimal strategies for distributing observations. That is, G theory can be used to determine how a fixed number of observations should be distributed across raters, occasions, or cases to optimize reliability.

Estimation of Field Populations of Cyst forming Nematodes of the GenusHeterodera

1961 ◽  
Vol 35 (S1) ◽  
pp. 63-76 ◽  
Author(s):  
D. W. Fenwick
Keyword(s):  
Crop Rotation ◽  
The Other ◽  
Sources Of Error ◽  
Different Types ◽  
Order Of Magnitude ◽  
Resistant Strains ◽  
The One ◽  
Different Sources ◽  
Factual Data ◽  
Types Of Error

Despite many recent advances in the study of nematicides and in the breeding of resistant strains of plants, control of cyst forming nematodes is still best accomplished by crop rotation; to be fully effective, it is also desirable that a field in which it is proposed to grow a susceptible crop should be sampled and an estimate made of the population of nematodes present: such an estimate is susceptible to different sources of error and although it is possible to decrease the magnitude of these errors a compromise has to be reached between the conflicting claims of precision on the one hand and the expenditure of man-power on the other; it is desirable that this compromise be based on factual data rather than guesswork; good estimates of the order of magnitude of the different types of error are therefore desirable.

Uncertainty and Interpretive Error

2019 ◽  
pp. 3-28
Author(s):  
Michael A. Bruno
Keyword(s):  
Diagnostic Imaging ◽  
Medical Diagnosis ◽  
Cognitive Biases ◽  
Anatomic Variation ◽  
High Variability ◽  
Error Sources ◽  
Sources Of Uncertainty ◽  
Sources Of Error ◽  
Course Of Action

Uncertainty pervades medical diagnosis and can rarely be entirely eliminated. Diagnostic imaging is meant to reduce that uncertainty, ideally to the point where a clinician feels confident enough to choose a course of action. But the process of diagnostic imaging is itself prone to high variability and error. Sources of variability include technical, procedural, and anatomic variation, the variable use of language to describe and report radiological abnormalities, and the range of variability in the manifestations of disease processes Cognitive biases and varying understanding of the prevalence and likelihood of disease among radiologists can also lead to interpretive error. This chapter explores the sources of error and the sources of uncertainty in the radiological process. There is considerable overlap between the two.

scholarly journals Recent proposals to estimate transient error within the classical test theory tradition

2006 ◽  
Vol 32 (4) ◽  
Author(s):  
G K Huysamen
Keyword(s):  
Classical Test Theory ◽  
Estimation Method ◽  
Reliability Estimation ◽  
Test Theory ◽  
Coefficient Alpha ◽  
Classical Test ◽  
Sources Of Error ◽  
Transient Error ◽  
Different Sources ◽  
Generalisability Theory

Reliability is conceptually defined in terms of consistency across test occasions but coefficient alpha, the most popular reliability estimation method, precludes the examination of such consistency. Three recent proposals to estimate transient error separately within a classical test theory tradition, and the results that they have yielded are reviewed. The merits of these proposals are compared with those of generalisability theory which differentiates between different sources of error variation. Although the procedures reviewed cannot match the advantages of generalisability theory, they may be sufficient in many applications.

XX. Of the effects of the density of air on the rates of chronometers

1824 ◽  
Vol 114 ◽  
pp. 372-412
Keyword(s):  
Royal Society ◽  
Variable Density ◽  
Sources Of Error ◽  
The Subject ◽  
Points Of View ◽  
Different Sources

Among the different sources of error to which chronometers are commonly considered to be liable, the effects of the variable density of the medium in which the balance performs its vibrations has, in some degree, been overlooked. That changes in the density of the medium, produce however a sensible influence on the rate of a delicate time-keeper will, I hope, clearly and satisfactorily appear, from the detail of the experiments, now respectfully submitted to the Royal Society. The investigation of the subject has been undertaken in the four following points of view: First , by subjecting different chronometers to a less pressure than that afforded by the ordinary state of the amosphere at the level of the ocean. Secondly , by submitting them to a greater pressure than that afforded by the atmosphere under the same conditions. Thirdly , by removing chronometers from condensed into rarified air, and vice versa . And fourthly , to determine how far the rates of chronometers are affected by the ordinary aberrations of atmopheric pressure at the level of the sea.

scholarly journals Investigation of Systematic Errors for the Hybrid and Panoramic Scanners

2014 ◽  
Vol 71 (4) ◽  
Author(s):  
Mohd Azwan Abbasa ◽  
Halim Setan ◽  
Zulkepli Majid ◽  
Albert K. Chong ◽  
Lau Chong Luh ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Error Sources ◽  
System Calibration ◽  
Vertical Circle ◽  
3D Data ◽  
Short Period ◽  
Laser Scanners ◽  
The Many ◽  
Different Sources

The existence of terrestrial laser scanners (TLSs) with capability to provide dense three-dimensional (3D) data in short period of time has made it widely used for the many purposes such as documentation, management and analysis. However, similar to other sensors, data obtained from TLSs also can be impaired by errors coming from different sources. Then, calibration routine is crucial for the TLSs to ensure the quality of the data. Through self-calibration, this study has performed system calibration for hybrid (Leica ScanStation C10) and panoramic (Faro Photon 120) scanner at the laboratory with dimensions 15.5m x 9m x 3m and more than hundred planar targets that were fairly distributed. Four most significant parameters are derived from well-known error sources of geodetic instruments as constant (a0), collimation axis (b0), trunnion axis (b1) and vertical circle index (c0) errors. Data obtained from seven scan-stations were processed, and statistical analysis (e.g. t-test) has shown significant errors for the calibrated scanners.

scholarly journals Assessment of the Errors in the Transmission of the Orientation and Cartographic System from the Surface to an Underground Mine

2018 ◽  
Author(s):  
Lluís Sanmiquel ◽  
Marc Bascompta ◽  
Josep M. Rossell
Keyword(s):  
Technological Progress ◽  
Mining Industry ◽  
Mine Ventilation ◽  
Base Line ◽  
Sources Of Error ◽  
Underground Infrastructure ◽  
Important Challenge ◽  
Underground Workings ◽  
Different Sources

A proper transmission of the orientation between surface and underground workings, by means of vertical shafts, is an important challenge in the mining industry, especially when the mine exceeds 200 meters deep. In fact, this study is developed in a mine located to 700 meters deep. Likewise, this paper assesses the accuracy of this operation, in a case study, using the two shafts plumbing and gyroscope methods in order to compare and analyse the planimetric displacement of the base line due to different source of errors in each one. Upsides and downsides of both methods are analysed in the paper. Some disadvantages in each method have been reduced thanks to the technological progress, especially in the two shaft plumbing method. The different sources of error that affect the measures are thoroughly analysed in the study with the aim to compensate them and achieve the required precision for an underground infrastructure. Mine ventilation has been found as one of the most important sources of error in the plumbing method due to intake and return airflow. In this direction, the paper unfolds some measures to reduce the ventilation influence and details a compensation method to reduce ventilation errors.

Critical appraisal of the cone penetration method of determining soil plasticity

2006 ◽  
Vol 43 (8) ◽  
pp. 884-888 ◽  
Author(s):  
K Prakash ◽  
A Sridharan
Keyword(s):  
Laboratory Tests ◽  
Critical Appraisal ◽  
Soil Classification ◽  
Liquid Limit ◽  
Cone Penetration ◽  
Soil Plasticity ◽  
Testing Procedures ◽  
Thread Rolling ◽  
Rolling Method ◽  
Undrained Strength

Plasticity is a characteristic feature that all plastic soils possess. It is shown that the soil plasticity is mainly due to undrained cohesion. Soil plasticity characteristics obtained from laboratory tests are reasonable for use only when the testing procedures adopted to determine them measure the factors responsible for the soil plasticity. It is shown that this is the case with the percussion method of liquid limit determination and the 3 mm thread rolling method of plastic limit determination. Further, it is also shown that the results obtained from the cone penetration method cannot represent the soil plasticity fully, as the mechanisms that come into play during testing relate to undrained strength due to both undrained cohesion and undrained friction. It is stressed that the percussion and 3 mm thread rolling methods must be the only ones used to determine the plasticity of soils. The circumstance under which the cone penetration method can be used is also indicated.Key words: clays, laboratory tests, plasticity, soil classification.

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