• Bulletin of the Korean Mathematical Society
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• v.59 no.3
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• pp.547-566
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• 2022

Let T be a bilinear Calderón-Zygmund operator, $b{\in}U_q>_1L^q_{loc}(G)$. We firstly obtain a constructive proof of the weak factorisation of Hardy spaces. Then we establish the characterization of BMO spaces by the boundedness of the commutator [b, T]_j in variable Lebesgue spaces.

• Communications for Statistical Applications and Methods
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• v.19 no.3
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• pp.405-414
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• 2012

In a stratified sample, the sampling frame is divided into non-overlapping groups or strata (e.g. geographical areas, age-groups, and genders). A sample is taken from each stratum, if this sample is a simple random sample it is referred to as stratified random sampling. In this paper, we study the bootstrap inference (including confidence interval) and test for a stratified population mean. We also introduce the bootstrap consistency based on limiting distribution related to the plug-in estimator of the population mean. We suggest three bootstrap confidence intervals such as standard bootstrap method, percentile bootstrap method and studentized bootstrap method. We also suggest a bootstrap test method computing the $ASL_{boot}$(Achieved Significance Level). The results of estimation are verified using simulation.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.8
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• pp.1033-1041
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• 2003

Two-phase flow pattern data during horizontal in-tube flow boiling are presented for pure and mixed refrigerants of R134a and Rl23, The flow pattern is observed through tubular sight glasses located at inlet and outlet of the test section, which is made of a stainless steel tube, 2m long with 10mm I.D., 1.5mm wall thickness. The obtained results are compared with the available various correlations for flow pattern. The flow pattern map of Hashizume was in good agreement with the present data except the region of low mass velocity. Weisman flow pattern map was also known to satisfactorily predict data for refrigerants in the region of annular flow. In this study, the flow pattern are simply classified into two groups; stratified(including intermittent, stratified and stratified-wavy) flow and annular flow. The transition quality from stratified to annular flow was obtained by modifying the liquid Froude number.

• The Korean Journal of Applied Statistics
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• v.23 no.6
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• pp.1081-1091
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• 2010

Clinical trials are often carried out as multi-center studies because the patients enrolled for a trial study are very limited in one particular hospital. In these circumstances, the use of an ordinary Jonckheere (1954) and Terpstra (1952) test for testing trend among several independent treatment groups is invalid. We propose a the stratified Jonckheere-Terpstra test based on van Elteren (1960)'s stratified test of Wilcoxon (1945) statistics and an application of our method is demonstrated through example data. A simulation study compares the efficiency of stratified and unstratified Jonckheere-Terpstra trend tests.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.12
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• pp.5251-5256
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• 2016

Background: Diagnostic karyotyping analysis is routinely used in acute myeloid leukemia (AML) clinics. Categorization of patients into risk stratified groups (favorable, intermediate and adverse) according to cytogenetic findings can serve as a valuable independent prognostic factor. Method and Material: A retrospective descriptive study was conducted based on the patient records of newly diagnosed non-M3 AML young adult cases undergoing standard 3+7 i.e, Daunorubicin and Ara-C (DA) as remission induction chemotherapy. Diagnostic cytogenetic analysis reports were analyzed to classify the patients into risk stratified groups according to South West Oncology Group criteria and prognostic significance was measured with reference to achievement of haematological remission after 1st induction chemotherapy. Results:A normal karyotype was commonly expressed, found in 47.2% of patients, while 65% (n=39) appeared to have intermediate risk cytogenetics, and 13.3% (n=8) adverse or unclassified findings. Favourable cytogenetics was least frequent in the patient cohort, accounting for only 8.3 % (n=5).The impact of cytogenetic risk groups on achievement of haematological remission was evaluated by applying Pearson Chi-square, and was found to be non-significant (df=12, p=0.256) but when the outcomes of favourable risk groups with intermediate, adverse and unclassified findings compared, results were highly significant (df=6, p=0.000) for each comparison. In patients of the favourable cytogenetic risk group, HR?? was reported in 40% (n=2/5), as compared to 62.2% (n=23/37) in the intermediate cytogenetic risk group, 57.1% (n=4/7) in the adverse cytogenetic risk group and 28.6% (n=2/7) in hte unclassified cytogenetic risk group. Conclusion: Cytogenetic risk stratification for AML cases following criteria provided by international guidelines did not produce conclusive results in our Pakistani patients. However, we cannot preclude an importance as the literature clearly supports the use of pretreatment karyotyping analysis as a significant predictive marker for clinical outcomes. The apparent differences between Pakistani and Western studies indicate an urgent need to develop risk stratification guidelines according to the specific cytogenetic makeup of South Asian populations.

• Imaging Science in Dentistry
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• v.54 no.1
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• pp.71-80
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• 2024

Purpose: This study aimed to evaluate age-stratified radiographic features in temporomandibular joint osteoarthritis using cone-beam computed tomography. Materials and Methods: In total, 210 joints from 183 patients(144 females, 39 males, ranging from 12 to 88 years old with a mean age of 44.75±19.97 years) diagnosed with temporomandibular joint osteoarthritis were stratified by age. Mandibular condyle position and bony changes (flattening, erosion, osteophytes, subchondral sclerosis, and subchondral pseudocysts in both the condyle and articular eminence, thickening of the glenoid fossa, joint space narrowing, and joint loose bodies) were evaluated through cone-beam computed tomography. After adjusting for sex, the association between age groups and radiographic findings was analyzed using both a multiple regression model and a multinomial logistic regression model(α=0.05). Results: The prevalence of joint space narrowing and protruded condyle position in the glenoid fossa significantly increased with age (P<0.05). The risks of bony changes, including osteophytes and subchondral pseudocysts in the condyle; flattening, erosion, osteophyte, and subchondral sclerosis in the articular eminence; joint loose bodies; and thickening of the glenoid fossa, also significantly rose with increasing age (P<0.05). The number of radiographic findings increased with age; in particular, the increase was more pronounced in the temporal bone than in the mandibular condyle (P<0.05). Conclusion: Increasing age was associated with a higher frequency and greater diversity of bony changes in the temporal bone, as well as a protruded condyle position in the glenoid fossa, resulting in noticeable joint space narrowing in temporomandibular joint osteoarthritis.

• Physical Therapy Korea
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• v.8 no.2
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• pp.87-94
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• 2001

Dexterity is defined in the present study as interdigital manipulative skill or the fine manipulative movements of objects held between the thumb and fingers. The Grooved pegboard test has been used to evaluate dexterity requring visual-motor coordination. The purpose of this study was to standardize the completion time of the Grooved pegboard test in different age groups and gender. Normative values for the Grooved Pegboard Test was developed on the sample of 282 healthy volunteers (89 men and 183 women). Subjects were stratified according to gender and dominant hand and were subdivided into six groups by blocking. The results of this study were as follows: 1) There was a significant difference in completion time between dominant and nondominant hand in both men and women groups (p<.05). 2) There were significant differences in completion time between men and women group (p<.05) 3) There were significant differences in completion time among age groups (p<.05).

• Journal of Oriental Neuropsychiatry
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• v.15 no.1
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• pp.27-41
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• 2004

This study was performed to evaluate the effects of Jowiseungchungtang and fluoxetine in the chronic mild stress(CMS) model of depression in rats. Chronic exposure to mild unpredictable stress was found to depress the consumption of sucrose solution in rats for 5 weeks. These CMS-treated rats were stratified into Jowiseungchungtang group, fluoxetine group and vehicle group. And control rats were also stratified into other CMS-treated group. The change of the consumption of sucrose solution was measured, and open field test were performed to investigate the anti-depression effect of Jowiseungchungtang and fluoxetine. The results were as follows : 1. The consumption of sucrose solution was significantly reversed in Jowiseungchungtang-treated group at 7 week, but there was no significant change in other groups. 2. CMS schedule decreased body weight. Jowiseungchungtang group and fluoxetine group showed significant decrease of body weight after 6 weeks. 3. In open field test, Jowiseungchungtang group and fluoxetine group showed no significant change of exploratory activity.

• Proceedings of the Korean Nuclear Society Conference
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• 1997.10a
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• pp.481-486
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• 1997

The interfacial shear stress is experimentally investigated for co-current air-water stratified flow in inclined rectangular channels having a length of 1854mm, width of 120mm and height of 40mm at almost atmospheric pressure. Experiments are carried out in several inclinations from $0^{\circ}\;up\;to\;10^{\circ}$. The local film thickness and the wave height are measured at three locations, i.e., L/H = 8,23, and 40. According to the inclination angle, the experimental data are categorized into two groups; nearly horizontal data group ($0^{\circ}\;{\leq}\;{\theta}\;{\leq}\;0.7^{\circ}$), and inclined channel data group ($0.7^{\circ}\;{\leq}\;{\theta}\;{\leq}\;10^{\circ}$). Experimental observations for nearly horizontal data group show that the flow is not fully developed due to the water level gradient and the hydraulic jump within the channel. For the inclined channel data group, a dimensionless wave height, $\Delta$h/h, is empirically correlated in terms of $Re_{G}$ and h/H. A modified root-mean-square wave height is proposed to consider the effects of the interfacial and wave propagation velocities. It is found that an equivalent roughness has a linear relationship with the modified root-mean-square wave height and its relationship is independent of the inclination.

• Journal of Preventive Medicine and Public Health
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• v.49 no.1
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• pp.61-68
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• 2016

Objectives: In South Korea (hereafter Korea), the number of adolescent offspring of immigrants has rapidly increased since the early 1990s, mainly due to international marriage. This research sought to examine the association between the experience of school violence and mental health outcomes, and the role of help-seeking behaviors in the association, among biethnic adolescents in Korea. Methods: We analyzed cross-sectional data of 3627 biethnic adolescents in Korea from the 2012 National Survey of Multicultural Families. Based on the victim's help-seeking behavior, adolescents who experienced school violence were classified into three groups: 'seeking help' group; 'feeling nothing' group; 'not seeking help' group. Multivariate logistic regression was applied to examine the associations between the experience of school violence and depressive symptoms for males and females separately. Results: In the gender-stratified analysis, school violence was associated with depressive symptoms in the 'not seeking help' (odds ratio [OR], 7.05; 95% confidence interval [CI], 3.76 to 13.23) and the 'seeking help' group (OR, 2.77; 95% CI, 1.73 to 4.44) among male adolescents after adjusting for potential confounders, including the nationality of the immigrant parent and Korean language fluency. Similar associations were observed in the female groups. However, in the 'feeling nothing' group, the association was only significant for males (OR, 8.34; 95% CI, 2.82 to 24.69), but not females (OR, 0.77; 95% CI, 0.18 to 3.28). Conclusions: This study suggests that experience of school violence is associated with depressive symptoms and that the role of victims' help-seeking behaviors in the association may differ by gender among biethnic adolescents in Korea.