• Journal of Yeungnam Medical Science
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• v.39 no.4
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• pp.285-293
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• 2022

Background: This study was conducted to analyze the effects of low skeletal muscle mass index (SMI) and obesity on aging-related osteoarthritis (OA) in the Korean population. Methods: A total of 16,601 participants who underwent a dual-energy X-ray absorptiometry and 3,976 subjects with knee X-rays according to the modified Kellgren-Lawrence (KL) system were enrolled. Knees of ≥KL grade 2 were classified as radiologic OA. The severity of joint space narrowing (JSN) was classified by X-rays as normal, mild-to-moderate, and severe JSN in radiologic OA. The subjects were grouped as normal SMI (SMI of ≥-1 standard deviation [SD] of the mean), low SMI class I (SMI of ≥-2 SDs and <-1 SD), and low SMI class II (SMI of <-2 SDs). Obesity was defined as a body mass index (BMI) of ≥27.5 kg/m². Results: The modified KL grade and JSN severity were negatively correlated with the SMI and positively correlated with BMI and age. The SMI was negatively correlated with age. JSN severity was significantly associated with a low SMI class compared to a normal SMI, which was more prominent in low SMI class II than class I. Obesity was significantly associated with more severe JSN, only for obesity with a low SMI class. Furthermore, patients with a low SMI class, regardless of obesity, were prone to having more severe JSN. Conclusion: This study suggested that a low SMI class was associated with aging and that an age-related low SMI was more critically related to the severity of JSN in OA.

• Journal of Forest and Environmental Science
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• v.30 no.1
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• pp.101-106
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• 2014

The purpose of this research was to figure out the stand structure and growth characteristic with relation to DBH, height, and volume in sixteen Pinus koraiensis plantations of Gangwon province region. Age class was diversely distributed from age class II (16 yr) to age class VIII (77 yr), and, in terms of site index, sixteen regions were superior: nine regions 'high', seven regions 'middle'. The distribution of DBH by sites appeared a bell-shaped curve, and the number of trees was the most in diameter section of 18-22 cm. The dispersion of DBH was various with age and widest ranging from 18 cm to 58 cm in age class VII-VIII. The distribution of height was also a bell-shaped curve with the smaller deviation than the distribution of DBH, and most of trees were in height section of 14-18 m. The correlation of DBH and height was high (r=0.75), and the volume bigger than 1.0 $m^3$ was presented from DBH 35 cm, height 20 m.

• Journal of Families and Better Life
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• v.29 no.1
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• pp.111-126
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• 2011

The aim of the present study was to compare child care center directors and teachers' recognition of criteria for class placements, specifically for children who were born in January or February, children's ability, and for mixed-age classes. The subjects were 398 center directors and 383 teachers in Seoul, Gyeonggi-do, Jeolla-do, Gangwon-do, Choongcheong-do and Gyeongsang-do. Data were analyzed by SPSS 12.0 and the t-test and Chi-square test were used. The results were as follows: (1) Most child care center directors and teachers believed that children born in January or February should share a classroom with classmates of the same age. (2) Most child care center directors and teachers believed that regardless of a child's ability, it was desirable for the child to be in a class with classmates of the same age. (3) Child care center directors thought that the current criteria for teacher-child ratios within a mixed-age classroom were acceptable but should be lowered if the child care center was not experiencing financial problems. Meanwhile, most of the teachers thought that lower teacher-child ratios within a mixed-age classroom was desirable.

• The korean journal of orthodontics
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• v.44 no.1
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• pp.13-19
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• 2014

Objective: The aim of this study was to evaluate long-term changes in the pharyngeal airway dimensions after functional appliance treatment in adolescents with skeletal Class II malocclusions. Methods: Pharyngeal airway dimensions were compared between subjects with skeletal Class II malocclusions (n = 24; mean age: $11.6{\pm}1.29$ years) treated with a Class II bionator and age-matched control subjects with skeletal Class I occlusions (n = 24; mean age: $11.0{\pm}1.21$ years) using a series of lateral cephalograms obtained at the initial visit (T0), after treatment (T1), and at the completion of growth (T2). Results: The length of the nasopharyngeal region was similar between adolescents with skeletal Class I and Class II malocclusions at all time points, while the lengths of the upper and lower oropharyngeal regions and the pharyngeal airway areas were significantly smaller in the skeletal Class II adolescents before treatment when compared to the control adolescents (p < 0.05). However, following treatment with a functional appliance, the skeletal Class II adolescents had increased pharyngeal airway dimensions, which became similar to those of the control subjects. Conclusions: Functional appliance therapy can increase the pharyngeal airway dimensions in growing adolescents with skeletal Class II malocclusions, and this effect is maintained until the completion of growth.

• International Journal of Reliability and Applications
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• v.3 no.1
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• pp.17-23
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• 2002

The class of “new better than used of a specified age” is a large and practical class of life distributions. Its properties, applicability, and testing was discussed by Hollander, Park and Proschan (1986). Their test, while remaining the yardstick for this class, suffers from weak efficiency and weak power, especially for specified ages below the average age. Thus, it is beneficial to have an alternative testing procedure that would work better for early ages and still work well for later ages. This is exactly the subject of the current note. The test developed here is also simpler than that of Hollander, et. al. (1986).

• The korean journal of orthodontics
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• v.47 no.4
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• pp.248-255
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• 2017

Objective: The purpose of this study was to investigate whether the craniofacial patterns of Korean children with snoring and adenotonsillar hypertrophy (ATH) could be categorized into characteristic clusters according to age. Methods: We enrolled 236 children with snoring and ATH (age range, 5-12 years) in this study. They were subdivided into four age groups: 5-6, 7-8, 9-10, and 11-12 years. Based on cephalometric analysis, the sagittal and vertical skeletal patterns of each individual were divided into Class I, II, and III, as well as the normodivergent, hypodivergent, and hyperdivergent patterns, respectively. Cluster analysis was performed using cephalometric principal components in addition to the age factor. Results: Three heterogeneous clusters of craniofacial patterns were obtained in relation to age: cluster 1 (41.9%) included patients aged 5-8 years with a skeletal Class I or mild Class II and hyperdivergent pattern; cluster 2 (45.3%) included patients aged 9-12 years with a Class II and hyperdivergent pattern; and cluster 3 (12.8%) included patients aged 7-8 years with a Class III and hyperdivergent pattern. Conclusions: This study found that the craniofacial patterns of Korean children with snoring and ATH could be categorized into three characteristic clusters according to age groups. Although no significantly dominant sagittal skeletal discrepancy was observed, hyperdivergent vertical discrepancy was consistently evident in all clusters.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.6
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• pp.324-333
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• 2018

The aim of this study was to investigate the latent classes and predictors of chronic diseases such as hypertension, dyslipidemia, arthritis, thyroid disease, depression, atopy, allergy, and diabetes. The subjects of this study were Korean citizens who participated in the Korea National Health and Nutrition Examination Survey in 2014. Stratified cluster sampling method was used with a sample size of 7,550. Latent hierarchy analysis was applied to this data. Four classes were identified. Class 1 consisted of participants with hypertension and diabetes. Class 2 consisted of participants with atopy and allergies. Class 3 consisted of participants with dyslipidemia, arthritis, thyroid disease, and depression. Class 4 consisted of participants without any chronic diseases. In comparing Class 1 to Class 4, age, physical activity, self-management, obesity, and presence of high cholesterol were found to be significant. In comparing Class 2 to Class 4, gender, age, and education level were significant. When Class 3 was compared to Class 4, gender, age, pain and discomfort, as well as high cholesterol were found to be significant. Diabetes and hypertension should be treated as comorbid conditions, applying integrated treatments involving effective drug treatment, diet, and physical activity programs. Atopy was found to be strongly correlated with allergies. Thyroid disease was found to coexist with dyslipidemia and arthritis, along with having a strong correlation to depression. Age-appropriate preventive measures can help reduce the risk of chronic diseases.

• International Journal of Reliability and Applications
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• v.16 no.1
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• pp.27-34
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• 2015

Based on increasing concave ordering a new class of life distribution is introduced. The new class of life distribution is named used better than aged in increasing concave ordering and is denoted by UBAC(2). The implication of our proposed class of life distribution with other classes is given. The properties of UBAC(2) under convolution, discrete mixture and formation of a coherent system are studied. Finally a characterization of the proposed class of life distributions by Laplace transform is discussed.

• The Journal of the Korean dental association
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• v.19 no.12 s.151
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• pp.1027-1030
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• 1981

2065 patients who visited orthodontic department form 1977. 7. 16. to 1981. 9. 30. were surveyed on the yearly tendency of patient distribution and the state of Angle's Classification. The results were as follows: 1. There was increased visiting rate of patient per year except the year 1980. 2. 8-13 age group was 55% in total visiting patient and 20 age over group was 11.0%. 3. Class I malocclusion was 42.3% in total visiting patient, more Class III malocclusion was prevalent than Class II malocclusion.

• Journal of Korean Society of Forest Science
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• v.12 no.1
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• pp.13-21
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• 1971

As one part of the ecological studies of Korean white pine plantation, a synecological survey was made on the undergrowth vegetation of Korean white pine plantations of different age class i.e., 5, 15, 25, 35, and 40 year age classes under which shrub and ground vegetation were distinctly different. And, the results are summarized as follows. 1. In shrub, the important species is Corylus heterophylla var. japonica and the dominant species in each age-class stand are as follows; 5 year-class ; Quercus mongolica, Lespedeza Maximowiczi. 15 year-class ; Corylus heterophylla var. japonica, Lespedeza Maximowiczi. 25 year-class ; Corylus heterophylla var. japonica. 35 year-class ; Corylus heterophylla var. japonica, Maackia amurensis. 40 year-class ; Corylus heterophylla var. japonica. 2. The higher the age class of the plantation are, the lower the height and the density of the shrub become. 3. Dominant species of ground-vegetation under the shrub of each age-class are as follows; 5 year-class ; Arundinella hirta var. cilia, Miscanthus purpurascens. 15 year-class ; Arundinella hirta var. ciliata, Potentilla Freyniana. 25 year-class ; Physematium manchuriense, Viola xanthopetala, Rubus craegifolius. 35 year-class ; Viola xanthopetala, Rubus crataegifolius. 45 year-class ; Viola xanthopetala, Rubus crataegifolius. 4. The standing crops of ground vegetation under the shrub were decreased with increasing age-class, which also caused the decreasing height and density and changing floristic composition of the shrub. 5. The ratio of the standing crop of root to the standing crop of shoot was increased as the age class increased. 6. The floristic composition of ground vegetation has shown a change from heliophyte to sciophytes on the sere.