• 대한치과교정학회지
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• 제10권1호
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• pp.15-27
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• 1980

This study was undertaken to compare the craniofacial morphology of Class II, Division 1 malocclusion with that of normal occlusion in children, and to investigate the incidence of various Class II, Division 1 craniofacial skeletal patterns. The subjects consist of thirty seven boys and fifty three girls with Class II, Division 1 malocclusion, and forty six boys and eighty one girls 10-15 years with normal occlusion. Measurements were recorded, tabulated and analyzed on the lateral cephalograms by the degree of SNA, SNB and ANB. The following characteristics of the Class II, Division 1 skeletal pattern were observed. 1. The anteroposterior relationship of the maxilla to the cranium in the Class II, Division 1 was very similar to that of normal occlusion. 2, Mandible of the Class II, Division 1 malocclusion was in the posterior position in relation to the cranial anatomy when compared to normal. 3. The chin point as measured by SN Pog and NS Gn showed distal positioning in relation to normal occlusion. 4. SN to mandibular plane angle was large in Class II, Division 1 malocclusion. 5. Mandibular incisor inclination was not significantly different between Class II, Division 1 malocclusion and normal occlusion, but maxillary incisors inclined and positioned labially and consequently overjet was large in Class II, Division 1 malocclusion. 6. Class II, Division 1 malocclusion was divided into four types of craniofacial skeletal pattern. The most common Class II, Division 1 pattern was found to be type C in which SN-Mand. Pl. was above mean range of normal occlusion. The next frequent pattern was found to be type A in which maxilla and mandible were within normal range of protrusion while upper incisors were severly labially inclined.

• 한국지반신소재학회논문집
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• 제17권1호
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• pp.85-93
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• 2018

현행 고속철도 교대 접속부 표준단면은 교대배면에서부터 시멘트안정처리골재, 일반골재, 토공부로 하부 지지강성이 점진적으로 변화하도록 설계하고 있다. 일반골재와 토공부의 배면기울기는 기울기가 클수록 구조적으로 안정적이지만 이에 대한 명확한 기준이 없다. 따라서 본 논문에서는 대형 원심모형실험기를 이용하여 교대 뒤채움 배면구간의 토공과 일반골재의 기울기를 변화하여 현행 표준단면과 침하 및 지지력 특성을 비교하였다. 실험결과 철도하중이 경험하는 하중단계에서는 1:2단면과 1:1.5 기울기 단면이 거의 유사한 성능을 가지고 있는 것으로 평가되었다.

• 한국지반공학회논문집
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• 제21권4호
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• pp.115-122
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• 2005

본 연구에서는 토사사면의 안전율을 산정하고 최소임계단면을 탐색하기 위하여 개별요소법과 유전자 알고리즘으로 조합된 새로운 해석방법이 제안되었다. 안전율 산정시, 한계평형법에 근거한 통상적인 사면안정 해석법들은 전체적인 힘평형을 만족하지 못하기 때문에 절편간에 작용하는 힘의 경사와 위치에 대한 가정이 불가피하다. 개별요소법에 근거하여 개발된 사면안정해석법은 힘과 변위간의 적합조건을 만족할 수 있다. 또한 제안된 해석기법에서는 최소임계 단면을 탐색하기 위하여 실수형 유전자 알고리즘이 적용되었다. 이 방법은 지역해에 쉽게 수렴하는 간편한 최적화기 법보다 안정적으로 전역해를 탐색할 수 있다 제안된 해석기법의 적용성을 검토하기 위하여 예제해석이 수행되었다.

• 한국환경과학회지
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• 제16권9호
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• pp.1011-1018
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• 2007

This study was conducted to analysis the ecological characteristics of "Wando HolIy"$(llex{\times}wandoensis)$ which is expecting as a possible ornamental tree with its beautiful leaves, flowers and fruits, and to find special breeding material which have particular characteristics and also provide correct environmental information which are required for commercial cultivation. The hill of Galmoon-Ri, Gunoei-Myon, Jeonnam Province, Korea, were reported as a original habitat of native $llex{\times}wandoensis$. The investigation shows that soil pH of native habitat was 6.18, hardness was 2.39, humidity was 38.6%, direction of slope is SSW, and average inclination was $15^{\circ}. The vegetation around $I.{\times}wandoensis$ is occupied by trees like an Quercus variabilis, Q. serrata, Q. acuta and so on. These are mixed forest of deciduous trees. Tree height reached up to about 12m and its coverage is about 30%. Q. salicina, Camellia japonica, I. integra, Cryptomeria japonica account for sub-tree layer. Tree height is around 8m and coverage is about 20%. Shrub layer was taken by Viburnum furcatum, Callicarpa japonica, Styrax japonica, Eurya japonica, Lindera obtusiloba, Ligustrum japonicum, Smilax china, Cornus walteri etc. Tree height reaches around l.2m and coverage is around 20%. Herb layer includes Trachelospermum asiaticum var. intermedium, Cymbidium goeringii, Dryopteris bissetiana, Disporum viridescens, Disporum smilacinum, Sasa borealis var. gracilis etc. Trachelospermum asiaticum var. intermedium, which are observed in southern evergreen zone, are dominant and its coverage is around 20%. The native habitat was in spoiled condition because of artificial thin out.

• 한국지구과학회지
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• 제25권6호
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• pp.409-417
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• 2004

본 연구는 초등학교 과학수업을 위한 ICT 활용 수업모듈의 개발과 그 효과를 알아보고자 하는 연구이다. 연구의 결과, 첫째, ICT 활용 수업모듈을 활용한 집단은 전통적 집단에 비해 과학 학업성취도를 향상시키는데 효과적이었다. 둘째, ICT 활용 수업모듈을 활용한 집단은 전통적 집단에 비해 자기주도적 학습특성을 향상시키는데 효과적이었다. 특히, 자기주도적 학습특성의 하위요소인 개방성, 자아개념, 솔선수범, 미래지향적 자기이해, 창의성, 자기 평가력에 대해서 향상을 보였다. 그러나 자기주도적 학습특성의 하위요소인 학습열성, 책임감에서는 향상된 효과를 보이지 않았다. 셋째, ICT 활용 수업모듈을 활용한 집단은 전통적 집단에 비해 창의성을 향상시키는데 효과적이었다. 이를 세부적으로 보면, 창의성의 하위요소인 유창성, 독창성에서는 향상을 보이고 있으나 융통성에서는 효과를 보이지 않았다.

• 대한치과교정학회지
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• 제6권1호
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• pp.17-24
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• 1976

The primary objective of this study was to define the differences that exist. between different sexes on the dentoskeletal framework and the soft tissue profile around the mouth. For the purpose of this study, cephalometric radiographs were obtained from the centric occlusion with closed lip position, through the research on each 42 males and females aged from 17 to 22 years with normal occlusion and acceptable facial appearence. The results were as follows: 1. Maxillary to mandibular relationships. Among the angles formed by the long axis of the maxillary and mandibular anterior teeth, the maxillary and mandibular anterior alveolar bone, and the lower and upper lips (Fig.2), only the angle formed by the lips was more acute in males than in females. The males have a more rounded profile, and the females have a flatter profile in the lower third of the face. The differences is statistically significant for the angle formed by the lips. The fact that the lips have a difference greater than that of teeth or the alveolar bone indicates that the lip position is not entirely due to tooth and bony support. Possibly the thickness of the lips has an influence. 2. Occlusal plane. The occlusal plane was related to the anterior tooth inclination, anterior alveolar bone profile, and the lip contour, both maxillary and mandibular (Fig.3). Only the angle related to lower lip was statistically significant. The females again had the more obtuse angle, indicating a flatter profile than that of the males. 3.Skeletal planes. The angles formed by the anterior maxillary lips, teeth, and alveolar bone with the Frankfort plane and the angles of the mandibular lips, teeth, and, alveolar bone and the mandibular plane were investigated (Fig.4). Results were similar to those from maxillary to mandibular relationships. The results were statistically significant for the upper lip and the lower lip, only. 4. Esthetics. The facial line and the mandibular plane were compared with the esthetic line. These angles were different for the different sexes, but only the latter was statistically significant. This difference may be due to the profile contour of the nose.

• 대한치과교정학회지
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• 제47권5호
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• pp.313-322
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• 2017

Objective: Miniscrew-assisted rapid palatal expansion (MARPE) is a means for expanding the basal bone without surgical intervention in young adults. Here, we assessed the differences in dental, alveolar, and skeletal measurements taken before (T0), immediately after (T1), and 1 year after (T2) MARPE. Methods: Twenty-four patients (mean age, 21.6 years) who had undergone MARPE and cone-beam computed tomography at T0, T1, and T2 were included. Changes in the following parameters were compared using paired t-tests: intercusp, interapex, alveolar, nasal floor, and nasal cavity widths; inclination of the first molar (M1) and its alveolus; and thickness and height of the alveolar bone. A linear mixed-effects model was used to determine variables that affected periodontal changes in the M1. Results: MARPE produced significant increases in most measurements during T0-T2, despite relapse of some measurements during T1-T2. The alveolar thickness decreased on the buccal side, but increased on the palatal side. The alveolar crest level at the first premolar moved apically. Changes in the thickness and height of the alveolar bone were affected by the corresponding initial values. Conclusions: MARPE can be used as an effective tool for correcting maxillomandibular transverse discrepancy, showing stable outcomes 1 year after expansion.

• 대한치과교정학회지
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• 제47권5호
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• pp.277-288
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• 2017

Objective: Treating Class II subdivision malocclusion with asymmetry has been a challenge for orthodontists because of the complicated characteristics of asymmetry. This study aimed to explore the characteristics of dental and skeletal asymmetry in Class II subdivision malocclusion, and to assess the relationship between the condyle-glenoid fossa and first molar. Methods: Cone-beam computed tomographic images of 32 patients with Class II subdivision malocclusion were three-dimensionally reconstructed using the Mimics software. Forty-five anatomic landmarks on the reconstructed structures were selected and 27 linear and angular measurements were performed. Paired-samples t-tests were used to compare the average differences between the Class I and Class II sides; Pearson correlation coefficient (r) was used for analyzing the linear association. Results: The faciolingual crown angulation of the mandibular first molar (p < 0.05), sagittal position of the maxillary and mandibular first molars (p < 0.01), condylar head height (p < 0.01), condylar process height (p < 0.05), and angle of the posterior wall of the articular tubercle and coronal position of the glenoid fossa (p < 0.01) were significantly different between the two sides. The morphology and position of the condyle-glenoid fossa significantly correlated with the three-dimensional changes in the first molar. Conclusions: Asymmetry in the sagittal position of the maxillary and mandibular first molars between the two sides and significant lingual inclination of the mandibular first molar on the Class II side were the dental characteristics of Class II subdivision malocclusion. Condylar morphology and glenoid fossa position asymmetries were the major components of skeletal asymmetry and were well correlated with the three-dimensional position of the first molar.

• 대한치과교정학회지
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• 제48권4호
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• pp.224-235
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• 2018

Objective: The purpose of this study was to compare the skeletal, dental, and soft-tissue treatment effects of nonextraction therapy using the modified C-palatal plate (MCPP) to those of premolar extraction (PE) treatment in adult patients with Class II malocclusion. Methods: Pretreatment and posttreatment lateral cephalographs of 40 adult patients with Class II malocclusion were retrospectively analyzed. The MCPP group comprised 20 patients treated with total arch distalization of the maxillary arch while the PE group comprised 20 patients treated with four PE. Fifty-eight linear and angular measurements were analyzed to assess the changes before and after treatment. Descriptive statistics, paired t-test, and multivariate analysis of variance were performed to evaluate the treatment effects within and between the two groups. Results: The MCPP group presented 3.4 mm of retraction, 1.0 mm of extrusion, and $7.3^{\circ}$ lingual inclination of the maxillary central incisor. In comparison, the PE group displayed greater amount of maxillary central incisor retraction and retroclination, mandibular incisor retraction, and upper lip retraction (5.3 mm, $14.8^{\circ}$, 5.1 mm, and 2.0 mm, respectively; p < 0.001 for all). In addition, the MCPP group showed 4.0 mm of distalization and 1.3 mm of intrusion with $2.9^{\circ}$ distal tipping of the maxillary first molars. Conclusions: These findings suggest the MCPP is an effective distalization appliance in the maxillary arch. The amount of incisor retraction, however, was significantly higher in the PE group. Therefore, four PE may be recommended when greater improvement of incisor position and soft-tissue profile is required.

• 대한정형도수물리치료학회지
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• 제21권2호
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• pp.39-46
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• 2015

Background: The purpose of this study was to investigate the influence of short-term treadmill walking with high-heeled shoes on electromyography activities of the medial gastrocnemius, lateral gastrocnemius and tibialis anterior in healthy young females. Methods: Fifteen healthy females were recruited for this study. To measure muscle activation, the subjects were asked in random order to walk on a treadmill using either high-heeled shoes or barefoot conditions. The shoe heel height for high-heeled walking was 7 cm. The walking speed on the treadmill was 4 km/h, and the inclination rate of the treadmill was 10%. The subjects performed treadmill walking in the barefoot and high-heeled walking conditions for 5 minutes. Electromyography data were collected from the tibialis anterior, medial gastrocnemius, lateral gastrocnemius, and soleus on both firm and foam surfaces and during eyes-open and-closed conditions while standing. Results: Tibialis anterior activity was significantly different before and after the walking task while standing on a foam surface with eyes closed (p<.05). Conclusion: This finding suggests that the activity of the tibialis anterior may be lowered after high-heeled walking. Therefore, high-heeled shoes contribute to harmful effects at the ankle joints, increasing the risks of falling and musculoskeletal injury.