Systematic and Random Errors Associated with Johnston's Cephalometric Analysis

1993 ◽  
Vol 20 (2) ◽  
pp. 101-107 ◽  
Author(s):  
Stephen D. Keeling ◽  
Sal R. Cabassa ◽  
Gregory J. King
Keyword(s):  
Random Error ◽  
Error Variance ◽  
Individual Case ◽  
Base Change ◽  
Mixed Dentition ◽  
Random Errors ◽  
Angular Measure ◽  
Basal Bone ◽  
Systematic And Random Errors ◽  
The Individual

This study examined intra- and interexaminer systematic and random errors associated with Johnston's cephalometric method of assessing skeletal and dental changes from pairs of radiographs. Data were obtained from the tracings of radiographs of 30 mixed dentition subjects, who had been treated to correct a Class II malocclusion. Measurements included molar and incisor crown movements relative to basal bone, apical base change, maxillary and mandibular displacement relative to the cranial base, and total molar and overjet reduction. In addition, the change in axial inclination of the incisors and molars was determined. A paired t- test for each pair of replicates for each measure was performed to examine inter- and intra-examiner bias. Estimates of the random error, the coefficient of reliability, and confidence limits (95 per cent level) of a single determination were undertaken. No systematic errors occurred between/within examiners for any linear or angular measure. Interexaminer random errors, based on the standard deviation of the mean difference between replicates, were greater than intra-examiner random errors for 12 out of 13 parameters. Measures assessing molar correction and overjet reduction had the least amount of random error variance within and across judges, while changes in mandibular position had the greatest. Because considerable random errors occurred, the Johnston analysis when used to assess skeletal changes, as well as individual molar and incisor movements, may have limited utility in clinical practice for the individual case.

scholarly journals Effects of systematic and random errors on the retrieval of particle microphysical properties from multiwavelength lidar measurements using inversion with regularization

2013 ◽  
Vol 6 (11) ◽  
pp. 3039-3054 ◽  
Author(s):  
D. Pérez-Ramírez ◽  
D. N. Whiteman ◽  
I. Veselovskii ◽  
A. Kolgotin ◽  
M. Korenskiy ◽  
...  
Keyword(s):  
Optical Data ◽  
Physical Parameters ◽  
Random Errors ◽  
Additive Property ◽  
Nasa Goddard Space ◽  
Microphysical Properties ◽  
Fine Mode ◽  
Systematic And Random Errors ◽  
The Individual ◽  
Multiwavelength Lidar

Abstract. In this work we study the effects of systematic and random errors on the inversion of multiwavelength (MW) lidar data using the well-known regularization technique to obtain vertically resolved aerosol microphysical properties. The software implementation used here was developed at the Physics Instrumentation Center (PIC) in Troitsk (Russia) in conjunction with the NASA/Goddard Space Flight Center. Its applicability to Raman lidar systems based on backscattering measurements at three wavelengths (355, 532 and 1064 nm) and extinction measurements at two wavelengths (355 and 532 nm) has been demonstrated widely. The systematic error sensitivity is quantified by first determining the retrieved parameters for a given set of optical input data consistent with three different sets of aerosol physical parameters. Then each optical input is perturbed by varying amounts and the inversion is repeated. Using bimodal aerosol size distributions, we find a generally linear dependence of the retrieved errors in the microphysical properties on the induced systematic errors in the optical data. For the retrievals of effective radius, number/surface/volume concentrations and fine-mode radius and volume, we find that these results are not significantly affected by the range of the constraints used in inversions. But significant sensitivity was found to the allowed range of the imaginary part of the particle refractive index. Our results also indicate that there exists an additive property for the deviations induced by the biases present in the individual optical data. This property permits the results here to be used to predict deviations in retrieved parameters when multiple input optical data are biased simultaneously as well as to study the influence of random errors on the retrievals. The above results are applied to questions regarding lidar design, in particular for the spaceborne multiwavelength lidar under consideration for the upcoming ACE mission.

scholarly journals Effects of systematic and random errors on the retrieval of particle microphysical properties from multiwavelength lidar measurements using inversion with regularization

2013 ◽  
Vol 6 (3) ◽  
pp. 4607-4644 ◽  
Author(s):  
D. Pérez-Ramírez ◽  
D. N. Whiteman ◽  
I. Veselovskii ◽  
A. Kolgotin ◽  
M. Korenskiy ◽  
...  
Keyword(s):  
Optical Data ◽  
Physical Parameters ◽  
Random Errors ◽  
Additive Property ◽  
Nasa Goddard Space ◽  
Microphysical Properties ◽  
Multi Wavelength ◽  
Fine Mode ◽  
Systematic And Random Errors ◽  
The Individual

Abstract. In this work we study the effects of systematic and random errors on the inversion of multi-wavelength (MW) lidar data, using the well-known regularization technique, to obtain vertically-resolved aerosol microphysical properties. The software implementation used here was developed at the Physics Instrumentation Center (PIC) in Troitsk (Russia) in conjunction with NASA/Goddard Space Flight Center. Its applicability to Raman lidar systems based on backscattering measurements at three wavelengths (355, 532 and 1064 nm) and extinction measurements at two wavelengths (355 and 532 nm) has been demonstrated widely. The systematic error sensitivity is quantified by first determining the retrieved parameters for a given set of optical input data consistent with two different sets of aerosol physical parameters. Then each optical input is perturbed by varying amounts and the inversion is repeated. We find a generally linear dependence of the retrieved errors in the microphysical properties on the induced systematic errors in the optical data. For the retrievals of effective radius, number/surface/volume concentrations and fine mode radius and volume, we found that these results are not significantly affected by the range of the constraints used in inversions. But significant sensitivity was found to the allowed range of the imaginary part of the particle refractive index to reach. Our results also indicate that exist an additive property for the deviations induced by the biases induced in the individual optical data. This permits the results here to be used to predict deviations in retrieved parameters when multiple input optical data are biased as well as to study the influence of random errors on the retrievals. The above results can be applied to questions regarding lidar design, as for example the space-borne multi-wavelength lidar to be deployed in the upcoming ACE mission anticipated to provide optical data with 15% accuracy in each of the lidar channels.

Statistics and parallaxes

1978 ◽  
Vol 48 ◽  
pp. 7-29
Author(s):  
T. E. Lutz
Keyword(s):  
Experimental Design ◽  
Statistical Methods ◽  
Review Paper ◽  
Systematic Errors ◽  
Past Experience ◽  
Random Errors ◽  
Trigonometric Parallaxes ◽  
Systematic And Random Errors

This review paper deals with the use of statistical methods to evaluate systematic and random errors associated with trigonometric parallaxes. First, systematic errors which arise when using trigonometric parallaxes to calibrate luminosity systems are discussed. Next, determination of the external errors of parallax measurement are reviewed. Observatory corrections are discussed. Schilt’s point, that as the causes of these systematic differences between observatories are not known the computed corrections can not be applied appropriately, is emphasized. However, modern parallax work is sufficiently accurate that it is necessary to determine observatory corrections if full use is to be made of the potential precision of the data. To this end, it is suggested that a prior experimental design is required. Past experience has shown that accidental overlap of observing programs will not suffice to determine observatory corrections which are meaningful.

Shoulder Pain at Work: Causation Analysis

2017 ◽  
Vol 22 (1) ◽  
pp. 11-16
Author(s):  
Joel Weddington ◽  
Charles N. Brooks ◽  
Mark Melhorn ◽  
Christopher R. Brigham
Keyword(s):  
Epidemiological Data ◽  
Case Law ◽  
Individual Case ◽  
Shoulder Injury ◽  
Work Related ◽  
Clear Cut ◽  
The Individual ◽  
Causation Analysis ◽  
Injury Causation ◽  
Relevant Factors

Abstract In most cases of shoulder injury at work, causation analysis is not clear-cut and requires detailed, thoughtful, and time-consuming causation analysis; traditionally, physicians have approached this in a cursory manner, often presenting their findings as an opinion. An established method of causation analysis using six steps is outlined in the American College of Occupational and Environmental Medicine Guidelines and in the AMA Guides to the Evaluation of Disease and Injury Causation, Second Edition, as follows: 1) collect evidence of disease; 2) collect epidemiological data; 3) collect evidence of exposure; 4) collect other relevant factors; 5) evaluate the validity of the evidence; and 6) write a report with evaluation and conclusions. Evaluators also should recognize that thresholds for causation vary by state and are based on specific statutes or case law. Three cases illustrate evidence-based causation analysis using the six steps and illustrate how examiners can form well-founded opinions about whether a given condition is work related, nonoccupational, or some combination of these. An evaluator's causal conclusions should be rational, should be consistent with the facts of the individual case and medical literature, and should cite pertinent references. The opinion should be stated “to a reasonable degree of medical probability,” on a “more-probable-than-not” basis, or using a suitable phrase that meets the legal threshold in the applicable jurisdiction.

Judicial Lawmaking, Discourse Theory, and the ICTY on Belligerent Reprisals

2011 ◽  
Vol 12 (5) ◽  
pp. 1261-1278 ◽  
Author(s):  
Milan Kuhli ◽  
Klaus Günther
Keyword(s):  
International Criminal Court ◽  
International Criminal ◽  
International Criminal Tribunal ◽  
Individual Case ◽  
Criminal Court ◽  
Discourse Theory ◽  
Criminal Courts ◽  
Normative Expectations ◽  
Judicial Lawmaking ◽  
The Individual

Without presenting a full definition, it can be said that the notion of judicial lawmaking implies the idea that courts create normative expectations beyond the individual case. That is, our question is whether courts' normative declarations have an effect which is abstract and general. Our purpose here is to ask about judicial lawmaking in this sense with respect to international criminal courts and tribunals. In particular, we will focus on the International Criminal Tribunal for the Former Yugoslavia (ICTY). No other international criminal court or tribunal has issued so many judgments as the ICTY, so it seems a particularly useful focus for examining the creation of normative expectations.

Assessing the validity of NART-estimated premorbid IQs in the individual case

1990 ◽  
Vol 29 (4) ◽  
pp. 435-436 ◽  
Author(s):  
J. R. Crawford ◽  
K. M. Allan ◽  
R. H. B. Cochrane ◽  
D. M. Parker
Keyword(s):  
Individual Case ◽  
The Individual

scholarly journals Evaluation of the SteamVR Motion Tracking System with a Custom-Made Tracker

2021 ◽  
Vol 11 (14) ◽  
pp. 6390
Author(s):  
Marcin Maciejewski
Keyword(s):  
Motion Tracking ◽  
Tracking System ◽  
Training System ◽  
Random Errors ◽  
Operational Conditions ◽  
Custom Made ◽  
Systematic And Random Errors ◽  
Position And Orientation ◽  
Motion Tracking System ◽  
System Operating

The paper presents the research of the SteamVR tracker developed for a man-portable air-defence training system. The tests were carried out in laboratory conditions, with the tracker placed on the launcher model along with elements ensuring the faithful reproduction of operational conditions. During the measurements, the static tracker was moved and rotated in a working area. The range of translations and rotations corresponded to the typical requirements of a shooting simulator application. The results containing the registered position and orientation values were plotted on 3D charts which showed the tracker’s operation. Further analyses determined the values of the systematic and random errors for measurements of the SteamVR system operating with a custom-made tracker. The obtained results with random errors of 0.15 mm and 0.008° for position and orientation, respectively, proved the high precision of the measurements.

Changing Beliefs About Emotions in IBS: A Single Case Design

2018 ◽  
Vol 47 (3) ◽  
pp. 303-317
Author(s):  
H.M. Bowers ◽  
A.L. Wroe
Keyword(s):  
Single Case ◽  
Individual Case ◽  
Single Case Design ◽  
Emotional Suppression ◽  
Cognitive Behavioural ◽  
Scale Scores ◽  
Irritable Bowel ◽  
The Individual ◽  
Beliefs About Emotions

Background: Previous research suggests benefits of targeting beliefs about the unacceptability of emotions in treatment for irritable bowel syndrome (IBS). Aims: The current study developed and tested an intervention focusing on beliefs and behaviours around emotional expression. Method: Four participants with IBS attended five group sessions using cognitive behavioural techniques focusing on beliefs about the unacceptability of expressing emotions. Bi-weekly questionnaires were completed and a group interview was conducted. This study used an AB design with four participants. Results: Averages indicate that participants showed decreases in beliefs about unacceptability of emotions and emotional suppression during the intervention, although this was not reflected in any of the individual trends in Beliefs about Emotions Scale scores and was significant in only one individual case for Courtauld Emotional Control Scale scores. Affective distress and quality of life improved during follow-up, with only one participant not improving with regard to distress. Qualitative data suggest that participants felt that the intervention was beneficial, referencing the value in sharing their emotions. Conclusions: This study suggests the potential for beliefs about emotions and emotional suppression to be addressed in cognitive behavioural interventions in IBS. That beliefs and behaviours improved before outcomes suggests they may be important processes to investigate in treatment for IBS.

On the Smoothing of Observed Data

1937 ◽  
Vol 33 (4) ◽  
pp. 444-450 ◽  
Author(s):  
Harold Jeffreys
Keyword(s):  
Standard Error ◽  
Random Error ◽  
Simple Function ◽  
Standard Errors ◽  
Random Errors ◽  
Previous Theory ◽  
Know How ◽  
True Value ◽  
Actual Error ◽  
Range Of Variation

1. It often happens that we have a series of observed data for different values of the argument and with known standard errors, and wish to remove the random errors as far as possible before interpolation. In many cases previous considerations suggest a form for the true value of the function; then the best method is to determine the adjustable parameters in this function by least squares. If the number required is not initially known, as for a polynomial where we do not know how many terms to retain, the number can be determined by finding out at what stage the introduction of a new parameter is not supported by the observations*. In many other cases, again, existing theory does not suggest a form for the solution, but the observations themselves suggest one when the departures from some simple function are found to be much less than the whole range of variation and to be consistent with the standard errors. The same method can then be used. There are, however, further cases where no simple function is suggested either by previous theory or by the data themselves. Even in these the presence of errors in the data is expected. If ε is the actual error of any observed value and σ the standard error, the expectation of Σε2/σ2 is equal to the number of observed values. Part, at least, of any irregularity in the data, such as is revealed by the divided differences, can therefore be attributed to random error, and we are entitled to try to reduce it.

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