• Title/Summary/Keyword: 상호 교정

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Effect of Cooperative Learning on Conceptual Change of Atmospheric and Water Cycle (대기와 물의 순환 개념변화에 대한 협동학습의 효과)

  • Jeong, Jin-Woo;Jang, Myoung-Duk;Chun, Seon-Lye
    • Journal of the Korean earth science society
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    • v.25 no.2
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    • pp.63-73
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    • 2004
  • This study investigated the effect of cooperative learning on the middle school students’ conceptual change of atmospheric and water cycle and also examined the verbal interaction patterns in a cooperative group. The study also analyzed the relationship between the verbal interaction and students’ conceptual change in the cooperative learning situation. Two classes from a middle school were selected as an experimental group (cooperative learning group, n = 37) and a control group (traditional learning group, n = 37), respectively. The experimental group was taught by STAD cooperative learning model and received collaborative skill training. The results of the study can be summarized as follows: first, there were no significant differences in conceptual change between the two groups. As for the middle-achieving students on the pretest, however, the score of the cooperative learning group was significantly higher than that of the traditional learning group. Secondly, verbal interaction in the cooperative learning situation mainly happened among high- and middle achieving students. In addition, the students who were successful in undergoing conceptual change had more frequent verbal interactions than the students who were not. The study suggests that it is more important to interact between a teacher and students than to interact between the students and students in order to correct students’ misconception.

A STATISTICAL STUDY ON THE CORRELATION BETWEEN THE NASOPHARYNGEAL SPACE AND THE DENTOFACIAL STRUCTURES (비인두강(鼻咽頭腔)과 안면골격간(顔面骨格間)의 상관관계(相關關係)에 대(對)한 통계학적(統計學的) 연구(硏究))

  • Oh, Sungjin;Kinoshita, Z
    • The korean journal of orthodontics
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    • v.17 no.2
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    • pp.255-277
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    • 1987
  • 부정교합(不正交合)의 발생요인(發生要因)의 하나로서 비인두강(鼻咽頭腔)의 협착(狹窄)이 거론(擧論)되어 왔다 본(本) 연구(硏究)는 안면골격(顔面骨格)의 형태결정(形態決定)에 비인두강(鼻咽頭腔)의 기여정도(寄與程度)를 파악(把握)하고자 함에 있다 연구자료(硏究資料) 및 방법안(方法安) 한국인(韓國人) 성인(成人) 남녀(男女) 156 명(名)의 측모두부X선규격사진(側貌頭部X線規格寫眞)을 사용(使用)하여 NEC PC-9801 VM2 Personal Computer와 Oscon GT-4000 Digitizer에 의한 data 입력(入力)을 행(行)한 후 통계처리(統計處理)를 행(行)하였다 통계처리(統計處理)로서는 각계측치(各計測値)에 대하여 남녀별(男女別)로 평균치(平均値), 표준편차치(標準偏差値)를 산출(算出), Student's t-test를 행(行)하고, 비인두강(鼻咽頭腔) 계측항목(計測項目)과 안면골격(顔面骨格)의 각(各) 계측치간(計測値間)의 상관관계(相關關係)의 검토(檢討)를 행(行)하였다 결(結) 과(果) 1 남녀(男女)의 성차(性差)로서, 여자(女子)보다 남자(男子)가 상악골(上顎骨)에 대해 하악골(下顎骨)이 돌출(突出)되어 있었으며, 안면고(顔面高)가 컸다 2 Ba-S-PNS와 S-PNS-Ba간(間)에 부(負)의 상관(相關)이 인정(認定)되어, 이 두 계측치간(計測値間)애 상호작용(相互作用)이 있는 것으로 판단 되었다 3 비인두강(鼻咽頭腔)의 깊이는 하악(下顎)의 전후위치관계(前後位置關係)와 유의(留意)한 상관관계(相關關係)를 보였다 4 비인두강(鼻咽頭腔)의 깊이와 안면(顔面)의 깊이와는 관련성(關聯性)이 없는 것으로 판단 되었다 5 비인두강(鼻咽頭腔)의 깊이와 안면고간(顔面高間)에 유의(有意)한 부(負)의 상관(相關)이 시사(示唆)되었다 6 비인두강(鼻咽頭腔)의 고경(高經)과 안면고간(顔面高間)에 유의(有意)한 상관관계(相關關係)가 인정(認定)되었다.

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A LONGITUDINAL ROENTGENO-CEPHALOMETRIC STUDY ON THE CEPHALO-FACIO-DENTAL RELATIONSHIPS OF NORMAL KOREAN CHILDREN AGED FROM 6 TO 11 YEARS BY SASSOUNI'S ANALYSIS (Sassouni분석법에 의한 한국 아동의 두개, 안모, 치아의 상호관계 변화에 관한 누년적 연구)

  • Ryu, Young Kyu
    • The korean journal of orthodontics
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    • v.17 no.2
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    • pp.165-183
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    • 1987
  • The purpose of this study is to investigate the cephalo-facio-dental relationships in the craniofacial complex and their changes with age, and to use them for diagnostic and treatment purposes in the orthodontics The author studied on the changes of the cephalo-facio-dental relationships, using serial lateral cephalometric roentgenograms of 46 boys and 47 girls aged from 6 to 11 years of normal Korean children Following results were obtained 1 Means and Standard deviation of Korean children were obtained. 2 In the evaluation of the craniofacial vertical proportions, lower anterior face was larger than the upper, and upper posterior face was larger than the lower at all ages 3 The growth change was more prominent in the anterior craniofacial vertical proportion than in the posterior, and growth increment in the upper anterior facial height dimension was larger than m the lower anterior. 4 In the evaluation of the craniofacial horizontal proportion, ANS, Pog, Go and 6 were all situated posterior to their reference ares, and point B was always situated anterior to the arc passing by point A. 5. Anteroposterior growth change was the most prominent in the mandible, and there was no significant difference between the horizontal growth increment in the cranial base and that in the maxilla 6 Growth increment in the horizontal direction was larger in the mandibular apical base than in the maxillary apical base 7 The upper central incisor and the upper first molar were gradually anterior positioned against their reference ares with age increase 8 The length of mandibular corpus was larger than that of cranial base from the seven years old, and the difference was increased as the age increased 9 With age, there was slight difference in the angular relationships formed by craniofacial reference planes and axial inclinations of upper and lower permanent teeth.

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A STUDY ON THE BITING FORCE OF ANTERIOR OPENBITE AND NORMAL OCCLUSION ADULTS (정상교합자와 전치부 개방교합자의 교합력에 관한 연구)

  • Kim, Dong-Ho;Lee, Dong-Joo
    • The korean journal of orthodontics
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    • v.25 no.4
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    • pp.487-495
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    • 1995
  • This study was undertaken to compare each maximum biting force and to investigate its relationship with the facial skeketal form, number and position of tooth contact between anterior openbite and normal occlusion adults, using the T-scan system and the lateral cephalogram. The subjects of this study consisted of a group of 25 individuals with normal occlusion and another group of 14 with anterior openbite. The obtained results of this study were as follows : 1. The maximum biting force of anterior openbite adults was less than that of normal occlusion adults. 2. In anterior openbite adults, there were negative correlations between the maximum, biting force and SN/MP, FMA, PP/MP mesurement of lateral cephalogram. 3. In anterior openbite adults, as the mesial angulation of lower first molar against the occlusal plane increased, the more the biting force decreased. 4. In both groups, the greater the number of tooth contact, the more the biting force increased. 5. In both groups, the center of effort for anteroposterior occlusal contact was located on the first molar region.

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Antenna Gain Measurement in Time Domain (시간 영역에서 안테나 이득 측정 연구)

  • Park, Jungkuy;Kim, Woo-Nyun
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.23 no.11
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    • pp.1217-1227
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    • 2012
  • There are several antenna calibration methods, so-called 3-Antenna Method, Standard Site Method, and Standard Antenna Method which measure the antenna gains or antenna factors. These methods yield the free space or quasi free space antenna gains in only the frequency domain. In this paper, an antenna calibration method using the time domain in the open area test site is discussed. The reflected waves due to the ground are traced in the time domain. After they are removed by the time gating function of network analyzer, the free space transmission coefficient $S_{21}$ is extracted. Such a way is applied to the broad band horn antenna ranging 1 GHz to 18 GHz, and the free space gains are obtained by Friis transmission equation. The method is checked by Standard Site Method in open area test site. The results show comparatively good agreement except for 18 GHz.

A STUDY ON RELATONS BETWEEN FACIAL SKELETAL PATTERNS AND DENTAL OCCLUSION (안골격형과 교합과의 상호관계에 대한 연구)

  • Chang, Young-Il
    • The korean journal of orthodontics
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    • v.12 no.1
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    • pp.21-26
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    • 1982
  • This study was undertaken to document relations between facial skeletal pattern and dental occlusion. The data in .this study were collected from pretreatment cephalometric radiographs and study models of patients' records present in the files of Orthodontic Department, Seoul National University Hospital. Patients were selected on the basis of a mandibular plane-sella nasion angle equal to or greater than $38^{\circ}$ (high SN-MP angle) or equal to or less than $26^{\circ}$ (low SN-MP angle). Patients in the mixed dentition and with missing permanent teeth were excluded for ease of assessing tooth size / arch circumference relationships and then 30 high SN-MP and 11 low SN-MP patients were selected among them. The mean age of these two groups of patients was high SN-MP, $12.8{\pm}1.23$ years and low SN-MP, $13.0{\pm}1.48$ years. The following conclusions were obtained. 1. In the maxilla and mandible the mean tooth size of high SN-MP patients was nearlly identical to the low SN-MP patients. 2. The mean maxillary arch circumference was increased in low SN-MP group compared with high SN-MP group and a smilar, but smaller, mean increase was present in mandible. 3. The difference between the mean maxillary circumference required and the mean maillary circumference present ranged from -4.8mm in the high SN-MP group to -1.3mm in the low SN-MP group. A small range of means occurred in the mandible (high SN-MP: -4.0mm to low SN-MP: -1.8mm). 4. In the maxilla and mandible the mean arch length was nearly identical in the high and low SN-MP groups. 5. The mean incisor inclination was increased as the SN-MP angle decreased in the maxilla and mandible. 6. The men distance of the maxillary first molar from anterior border of the pterygomaxillary fissure was nearly similar between high and low groups. 7. The mean mandibular intermolar width was increased from high SN-MP to low SN-MP patients.

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Construction of AC-DC Magnetic Field Standard Systems and Results of International Key Comparison (직류-교류 자기장 표준 시스템 제작 및 국제비교 결과)

  • Park, Po-Gyu;Kim, Young-Gyun
    • Journal of the Korean Magnetics Society
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    • v.14 no.6
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    • pp.201-206
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    • 2004
  • The AC-DC magnetic field standard systems were constructed for the calibration of magnetometers for low magnetic field and the tests for low magnetic field characteristics of sensors and materials. In the range of 1 mT, the expanded uncertainty of dc is 8${\times}$10$\^$-6/, ac uncertainties are 0.16% in 0.1~1 kHz, 0.26% in 1~5 kHz, and 0.44% in 5~20 kHz. We have been participated in international key comparison(KC) to achieve the equality and the mutual agreement between standard institutes for the results of calibrations and tests. KRISS participating in ac-dc magnetic flux density of KC got equal level of uncertainty results compare with the advanced nations. It confirm that measurement ability of magnetic flux density is high level in the world.

A Longitudinal Study on the Changes in Individual Local Government's Social Spending in South Korea (기초지방정부 사회복지비 지출비중의 변화요인 탐색)

  • Jang, Dong-Ho
    • Korean Journal of Social Welfare
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    • v.59 no.1
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    • pp.329-351
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    • 2007
  • This study analyzes the changes in individual local government's social spending from 1995 to 2004 in South Korea. Using the pooled time-series and cross-sectional data of 226 basic-level local governments, the resulting analyses of an error correction model are very interesting: First, a rising local population led to an immediate increase in social spending; Secondly, local governments gradually increased social spending when the elderly ratio had been high, but the levels of social spending in the previous year and local economy related spending level had been low. Thirdly, there were no spending changes associated with local elections and partisan politics. Fourthly, both cooperative and competitive intergovernmental relations had the most significant effect on the social spending and reduced geographical disparities in the level of spending across localities. In conclusion, this study suggests that we establish a more comprehensive intergovernmental network which lead to territorial justice in social welfare.

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Correlations between dental and skeletal maturity (치아성숙도와 골성숙도의 상호연관성에 관한 연구)

  • Lee, Young-Mi;Kim, Kwang-Won;Yoon, Young-Jooh
    • The korean journal of orthodontics
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    • v.30 no.2 s.79
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    • pp.143-157
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    • 2000
  • To investigate the developmental stages of dental and skeletal maturation by ages and the correlations among dental maturity, skeletal maturity of cervical vertebrae, and that of hand-and-wrist, the author used the cephalograms, orthopantomograms, and hand-and-wrist radiograms of 1055 patients (male 458, female 597) aged 7 to 20 years old. In the cephalograms, the skeletal maturity stages of each bone were mainly assessed by Hassel and Farman's cervical vertebrae maturation indicators (CVMI) method. In the orthopantomograms, the dental maturity stages of each tooth were mainly assessed by Nolla's tooth calcification stages method. In the hand-and-wrist radiograms, the skeletal maturity stages of each bone were mainly assessed by Fishman's skeletal maturity indicators (SMI) method. The results were as follows. 1. There was a high correlation among dental maturity, skeletal maturity of cervical vertebrae, and that of hand-and-wrist in the both sexes (P<0.001). 2. There was a high correlation (r=0.91-0.93) between skeletal maturity of cervical vertebrae and that of hand-and-wrist. 3. There was a high correlation (r>0.8) between skeletal maturity of hand-and-wrist and maturity of upper and lower canine, first premolar, and second premolar. 4. There was high a correlation(r=0.8) between skeletal maturity of cervical vertebrae and maturity of upper canine. 5. By the ages, dental maturity, skeletal maturity of cervical vertebrae, and that of hand-and-wrist were obtained in the both sexes. In summary, dental maturity, skeletal maturity of cervical vertebrae, and that of hand-and-wrist we of sufficient diagnostic worth as an index to predict adolescent growth.

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The effect of thickness and deflection of orthodontic thermoplastic materials on its mechanical properties (교정용 열가소성 재료의 두께와 변형량이 재료의 물리적 특성에 미치는 영향)

  • Min, Sam;Hwang, Chung-Ju;Yu, Hyung-Seog;Lee, Sang-Bae;Cha, Jung-Yul
    • The korean journal of orthodontics
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    • v.40 no.1
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    • pp.16-26
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    • 2010
  • Objective: The purposes of this study were to evaluate the force and stress depending on the type, deflection and thickness of the materials and to evaluate the mechanical properties of thermoplastic materials after repeated loading. Methods: Four types of thermoplastic products were tested. Force until the deflections of 2.0 mm and the stress when the materials were restoring to its resting position were evaluated. The mechanical properties of thermoplastic materials evaluated after 5 repeated loading cycles. Results: The interaction was observed between the thickness and the deflection (p < 0.05) from the regression equation. Thickness and amount of deflection rather than products and materials showed the largest effect on force and stress. In all products, at least 159 gf of force was required for more than 1.0 mm deflection or when materials with 1.0 mm thickness were deflected. The stress recorded was more than 19 gf/$mm^2$. During repeated loading, each group showed significant difference on the force and the stress (p < 0.01), 10 - 17% reduction of force and 4 - 7% reduction of stress in average. Conclusions: Proper thickness of thermoplastic materials and deflection level of tooth movement should be decided for the physiologic tooth movement. Force decay after repeated loading should be considered for the efficient tooth movement.