scholarly journals Correlation between spatial resolution and ball distortion rate of panoramic radiography

2020 ◽  
Author(s):  
Han-Gyeol Yeom ◽  
Sam-Sun Lee ◽  
Jo-Eun Kim ◽  
Kyung-Hoe Huh ◽  
Won-Jin Yi ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Spatial Resolution ◽  
Panoramic Radiography ◽  
Reference Value ◽  
Vertical Line ◽  
Line Pair ◽  
Horizontal Line ◽  
Student’S T ◽  
High Degree ◽  
Distortion Rate

Abstract BackgroundThe purpose of this study was to analyze the correlation between spatial resolution and ball distortion rate of panoramic radiography and to elucidate the minimum criterion for ball distortion rate, which is very relevant to clinical readability.MethodsHorizontal and vertical spatial resolution and ball distortion rates were calculated in the same position, such as the incisor, premolar, molar, and temporomandibular joint area with various object depths corresponding to 48 mm. Three devices were evaluated. A region showing spatial resolution above the reference standard was selected, and the ball distortion rate corresponding to the same region was divided into horizontal and vertical phantom groups.The mean and standard deviation of the obtained ball distortion rates were calculated. Student’s t-test was used to statistically analyze the mean difference in ball distortion rates between vertical and horizontal phantom groups.ResultsIn all devices, the horizontal line pair phantom, but not the vertical line pair phantom, was readable in all areas measured at the line pair value of at least 1.88 lp/mm. The line pair value tended to be higher toward the center and lower toward the outside. The ball distortion rate tended to decrease closer to the center and increased further away. In addition, ball distortion rates could not be measured at some areas as they were not recognized as balls due to the high degree of distortion at the outermost and innermost sides. The number of balls satisfying the reference value using the horizontal line pair phantom was 102 (mean of ball distortion rates, 20.98; standard deviation, 15.25). The number of balls satisfying the reference value using the vertical line pair phantom was 49 (mean of ball distortion rates, 16.33; standard deviation, 14.25). However, mean ball distortion rate was not significantly different between the two groups.ConclusionsFocal layer of panoramic radiography could be evaluated by the spatial resolution using horizontal and vertical line pair phantoms and by assessing ball distortion rates through a ball-type panorama phantom. A ball distortion rate of 20% could be used as a threshold to evaluate the focal layer of panoramic radiography.

scholarly journals Correlation between spatial resolution and ball distortion rate of panoramic radiography

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Han-Gyeol Yeom ◽  
Jo-Eun Kim ◽  
Kyung-Hoe Huh ◽  
Won-Jin Yi ◽  
Min-Suk Heo ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Panoramic Radiography ◽  
Distortion Rate

Design of High-Degree Student’s t-Based Cubature Filters

2017 ◽  
Vol 37 (5) ◽  
pp. 2206-2225 ◽  
Author(s):  
Yulong Huang ◽  
Yonggang Zhang
Keyword(s):  
Student’S T ◽  
High Degree

The situation of English speaker’s place of origin depending on Chinese dialects

2021 ◽  
Vol 29 (1) ◽  
pp. 161-171
Author(s):  
Min Wang
Keyword(s):  
Undergraduate Students ◽  
English Language ◽  
Native English Speakers ◽  
Speaking Rate ◽  
Advanced Degrees ◽  
Phonological Features ◽  
Place Of Origin ◽  
Chinese Dialects ◽  
Student’S T ◽  
High Degree

Abstract This study examines the ability to identify different Chinese dialects through the English language and evaluates how often respondents pay attention to phonological features and rate of speech to explain their categorizations. The research includes 100 Chinese undergraduate students and 100 young people without advanced degrees aged 20 to 25. Discrete independent data samples collected during the interview of participants are analyzed with the help of such statistical methods as Student's t-test, Mann-Whitney U-test, and Wilcoxon's test. The obtained results indirectly show the ability of respondents to identify native and non-native English speakers around the world, as well as determine their nationality. The outcomes of the paper explicate who, in general, categorize Chinese dialects better and which dialects are the most recognizable. Research data reveal a high degree of stereotypization of various dialects, especially the Beijing and U dialects. Moreover, based on the data obtained, it can be concluded that speaking rate significantly affects the perception and classification of a speaker from a particular province of China.

Mapping of a multilayer panoramic radiography device

2021 ◽  
Author(s):  
Luciano Augusto Cano Martins ◽  
Eduarda Helena Leandro Nascimento ◽  
Hugo Gaêta-Araujo ◽  
Matheus L Oliveira ◽  
Deborah Queiroz Freitas
Keyword(s):  
Exposure Time ◽  
Panoramic Radiography ◽  
Anterior Region ◽  
Panoramic Image ◽  
Panoramic Radiographs ◽  
Acrylic Plate ◽  
Panoramic Images ◽  
Maxilla And Mandible ◽  
Distortion Rate

Objective: To map the shape, location, and thickness of the focal trough of a panoramic radiography device with a multilayer imaging program. Methods: An acrylic plate (148 × 148 × 3 mm) containing 1156 holes distributed in a matrix of 34 × 34 rows was placed in the OP300 Maxio at the levels of the maxilla and mandible. 20 metal spheres (3.5 mm in diameter) were placed on the holes of the plate under 15 different arrangements and panoramic images were acquired for each arrangement at 66 kV, 8 mA, and an exposure time of 16 s. The resulting panoramic radiographs from the five image layers were exported, the horizontal and vertical dimensions of the metal spheres were measured in all images using the Image J software, and the magnification and distortion rates of the spheres were calculated. All metal spheres presenting a magnification rate lower than 30% in both vertical and horizontal dimensions and a distortion rate lower than 10% were considered to map the focal troughs of each of the five image layers. Results: All panoramic image layers had a curved shape ranging from 39° to 51° for both dental arches and varied in position and thickness. The anterior region of maxilla was anteriorly displaced when compared to the anterior region of the mandible for all layers. Image layers are thicker at the level of the mandible than those at the level of the maxilla; also, inner layers were thinner and outer layers were thicker. Conclusion All image layers in the studied panoramic radiography device had a curved shape and varied in position and thickness. The anterior region of maxilla was anteriorly displaced when compared to that of the mandible for all layers.

A NEW METHOD OF PATTERN SHOOTING

Geophysics ◽  
1955 ◽  
Vol 20 (3) ◽  
pp. 539-564 ◽  
Author(s):  
J. O. Parr ◽  
W. H. Mayne
Keyword(s):  
Finite Number ◽  
Finite Length ◽  
Vertical Line ◽  
New Method ◽  
Horizontal Line ◽  
Wavelength Band ◽  
Continuous Band ◽  
Reversed Polarity ◽  
Multiple Detectors ◽  
Horizontal Area

In areas where reflection shooting is difficult, it is often necessary to attenuate the energy in a broad continuous band of disturbing wavelengths to less than a few hundredths of what would be recorded if all units were bunched together. The wavelength band of the attenuated energy should be adjacent to the band of reflection wavelengths received. Attenuation of the undesired energy is best accomplished with multiple detectors or charges. In many areas the pattern should attenuate energy horizontally propagated in all directions, not just in the direction of the detector line. Neither a finite number of uniformly effective, uniformly spaced units in line nor a uniformly effective sheet of finite length will accomplish this result. A system for gradation of the effectiveness of units described in this paper does produce this result (not only for in‐line disturbances but also for disturbances coming in from the side of the line). The attenuation band can be made broad with good attenuation or narrower with still better attenuation, as desired. The variation of effectiveness can be applied to detectors or charges arranged in a horizontal line, over a horizontal area, in a vertical line, or over a vertical area. The principle of varying effectiveness can also be applied to reversed‐polarity detectors in order to accentuate certain apparent wavelengths.

scholarly journals Reliable Acoustic Path and Direct-Arrival Zone Spatial Gain Analysis for a Vertical Line Array

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3462 ◽  
Author(s):  
Chunyu Qiu ◽  
Shuqing Ma ◽  
Yu Chen ◽  
Zhou Meng ◽  
Jianfei Wang
Keyword(s):  
Sound Propagation ◽  
Correlation Coefficients ◽  
Deep Ocean ◽  
Vertical Line ◽  
Horizontal Line ◽  
Acoustic Path ◽  
Vertical Arrays ◽  
Peak Structure ◽  
Line Array ◽  
Propagation Properties

A method is developed in this paper to calculate the spatial gain of a vertical line array when the plane-wave assumption is not applicable and when the oceanic ambient noise is correlated. The proposed optimal array gain (OAG), which can evaluate the array’s performance and effectively guide its deployment, can be given by an equation in which the noise gain (NG) is subtracted from the signal gain (SG); hence, a high SG and a negative NG can enhance the performance of the array. OAGs and SGs with different array locations are simulated and analyzed based on the sound propagation properties of the direct-arrival zone (DAZ) and the reliable acoustic path (RAP) using ray theory. SG and NG are related to the correlation coefficients of the signals and noise, respectively, and the vertical correlation is determined by the structures of the multipath arrivals. The SG in the DAZ is always high because there is little difference between the multipath waves, while the SG in the RAP changes with the source-receiver range because of the variety of structure in the multiple arrivals. The SG under different conditions is simulated in this work. The “dual peak” structure can often be observed in the vertical directionality pattern of the noise because of the presence of bottom reflection and deep sound channel. When the directions of the signal and noise are close, the conventional beamformer will enhance the correlation of not only the signals but also the noise; thus, the directivity of the signals and noise are analyzed. Under the condition of having a typical sound speed profile, the OAG in some areas of the DAZ and RAP can achieve high values and even exceed the ideal gain of horizontal line array 10 logN dB, while, in some other areas, it will be lowered because of the influence of the NG. The proposed method of gain analysis can provide analysis methods for vertical arrays in the deep ocean under many conditions with references. The theory and simulation are tested by experimental data.

scholarly journals Πρόγνωση ασθενών με κακοήθεια που εισάγονται στη μονάδα εντατικής θεραπείας

2013 ◽  
Author(s):  
Σουσάνα Ανίσογλου
Keyword(s):  
Standard Deviation ◽  
Performance Status ◽  
T Test ◽  
Apache Ii ◽  
Saps Ii ◽  
Student’S T ◽  
Student’S T Test

ΣΚΟΠΟΣ: Η συλλογή, ανάλυση και επεξεργασία στοιχείων ογκολογικών ασθενών που νοσηλεύθηκαν στη Μονάδα Εντατικής Θεραπείας (Μ.Ε.Θ.) και η συσχέτισή τους με συγκεκριμένους πιθανούς παράγοντες κινδύνου .ΥΛΙΚΟ: Πρόκειται για μία προοπτική μελέτη παρατήρησης (prospective observational) σε δείγμα 125 ογκολογικών ασθενών που νοσηλεύθηκαν στη Μ.Ε.Θ. κατά την τελευταία διετία.ΜΕΘΟΔΟΣ: Αξιολογήθηκαν επιδημιολογικοί, κλινικοί και λειτουργικοί παράγοντες. Ειδικότερα ελέγχθηκαν η πρωτοπαθής νεοπλασματική νόσος, η ηλικία, η παρουσία στεφανιαίας νόσου, χρόνιας αποφρακτικής πνευμονοπάθειας, σακχαρώδους διαβήτη, νεφρικής ανεπάρκειας, ο δείκτης μάζας σώματος, η εφαρμογή χημειοθεραπείας ή και ακτινοθεραπείας, η διάρκεια νοσηλείας, τα score βαρύτητας (APACHE II, SAPS II, SOFA) και η έκβαση (εξιτήριο ή θάνατος) και έγιναν συσχετίσεις με τα προηγούμενα στοιχεία. Χρησιμοποιήθηκε το στατιστικό λογισμικό πακέτο SPSS 17.0 (SPSS, Chicago, IL, USA) για Windows. Οι συνεχείς μεταβλητές παρουσιάζονται ως μέσοι όροι + τυπική απόκλιση (mean + standard deviation). Για τη σύγκριση των μέσων όρων μεταξύ δύο ομάδων έγινε χρήση του student’s t-test, εφόσον οι μεταβλητές ακολουθούσαν την κανονική κατανομή και του Mann-Whitney U test στην αντίθετη περίπτωση. Για την ανάδειξη συσχετίσεων μεταξύ ποιοτικών μεταβλητών έγινε χρήση του x2 test.ΑΠΟΤΕΛΕΣΜΑΤΑ: Η θνητότητα ανήλθε στο 48.8%. Στατιστικά σημαντικοί παράγοντες κακής έκβασης κατά την εισαγωγή του ασθενούς στη ΜΕΘ ήταν τα score βαρύτητας (APACHE II, SAPS II, SOFA), το πτωχό performance status και τα συνυπάρχοντα σοβαρά νοσήματα. Στατιστικά σημαντικοί παράγοντες κακής έκβασης κατά τη διάρκεια νοσηλείας του ασθενούς στη Μ.Ε.Θ. ήταν η διάρκεια του μηχανικού αερισμού, η χρήση αγγειοσυσπαστικών, η πολυοργανική ανεπάρκεια και η σηπτική κατάσταση. Από τις εργαστηριακές εξετάσεις στατιστικά σημαντικές ήταν ο χαμηλός αριθμός αιμοπεταλίων και η θετική αιμοκαλλιέργεια. Ο στατιστικός έλεγχος αξιολόγησης κατά Hosmer Lemeshow παρά τον σχετικά μικρό αριθμό του δείγματος επιβεβαίωσε τη χρησιμότητα των APACHE II, SAPS II, SOFA ως προγνωστικών μοντέλων.ΣΥΜΠΕΡΑΣΜΑΤΑ: Η πρόγνωση ογκολογικών ασθενών που εισάγονται στη ΜΕΘ είναι μέτρια. Υπάρχουν σαφείς προγνωστικοί παράγοντες κινδύνου που μπορούν να συνθέσουν ένα είδος προγνωστικού μοντέλου, ωστόσο απαιτούνται περαιτέρω πολυκεντρικές μελέτες με προοπτικό χαρακτήρα σε μεγαλύτερο αριθμό ασθενών.

A model for the effect of bias for cholesterol on the population at risk.

1988 ◽  
Vol 34 (11) ◽  
pp. 2256-2259 ◽  
Author(s):  
M H Kroll ◽  
M Ruddel ◽  
R J Elin
Keyword(s):  
At Risk ◽  
Standard Deviation ◽  
Reference Values ◽  
Gaussian Distribution ◽  
Population Distribution ◽  
Reference Value ◽  
Mean Value ◽  
The Body ◽  
Methodological Bias ◽  
The Mean

Abstract The location of the Reference Value for an analyte within the population distribution affects the magnitude of error due to methodological bias. Using the gaussian distribution, we evaluated the effects of systematic and proportional biases of the method (positive and negative), mean value, and standard deviation on the magnitude of error. We chose four Reference Values for cholesterol as a model. For a population with a mean of 2.0 and SD of 0.36 g of cholesterol per liter, a 3% positive proportional bias causes sixfold more error at the 50th percentile than at the 97.5th. In general, the error for a given bias (proportional or systematic) is greater for a Reference Value within the body than at the tails of the distribution. Further, the magnitude of the error varies as a function of the mean and standard deviation of the population.

scholarly journals Assessment of maternal serum β hCG level in pregnancy induced hypertension and normotensive patients and to correlate between the level of β hCG with the severity of pre-eclampsia and eclampsia

2019 ◽  
Vol 8 (11) ◽  
pp. 4314
Author(s):  
Kapil Dev ◽  
Anoop Sharma ◽  
Rajeev Sood
Keyword(s):  
Standard Deviation ◽  
Elevated Serum ◽  
Fetal Outcome ◽  
Maternal Serum ◽  
Medical Complication ◽  
Normotensive Patient ◽  
The Mean ◽  
Student’S T ◽  
Β Hcg ◽  
One Year

Background: Hypertensive disorders during pregnancy are one of the most common medical complication seen during pregnancy, affecting around 5-10% of all pregnancies. Spectrum of this disease ranges from mildly elevated blood pressure with minimal clinical significance to severe hypertension with multi organ dysfunction. Pre-eclampsia complicates about 2-8% of all pregnancies. Pre-eclampsia incidence in India is about 8-10%. Various studies have depicted that, there is a strict relationship between PIH and elevated serum β-hCG level.Methods: This one-year prospective case control study toteled 200 pregnant women attending antenatal care and admitted in eclampsia ward fulfiling the inclusion criteria were studied. Serum βhCG levels were estimated by chemiluminescent microparticle immunoassay. Statistical analysis of data was done by student’s t-test and p-value.Results: The mean β hCG level in PIH patients was found to 36851.59 mIU/ml with standard deviation of 22916.58 while the mean β hCG in normotensive patient was 15433.26 mIU/ml with standard deviation of 6861.56. (p <0.001). The mean β hCG level in gestational hypertensive patients was 25206.19 mIU/ml with a standard deviation of 8696.9. The mean β hCG level in pre-eclamptic patients was 61697.67 mIU/ml with standard deviation of 18498.57. The mean β hCG level were 84106.38 mIU/ml with standard deviation of 11295.05 in the eclamptic patient. The above values were statistically significant (p <0.001).Conclusions: We concluded that there was a striking relation between the PIH including pre-eclampsia and eclampsia with the elevated serum βhCG level. Concluding that early detection of altered serum βhCG shell aid in better management of pre-eclampsia and eclampsia cases which would play a pivotal role in improving the maternal and fetal outcome.

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