• Journal of Dental Rehabilitation and Applied Science
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• v.24 no.2
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• pp.213-230
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• 2008

The aim of this study was to analyze the initial movement and the stress distribution of each tooth and periodontal ligament during the lingual lever-arm retraction of 6 maxillary incisors using FEA. Two kinds of finite element models were produced: 2-properties model (simple model) and 24-properties model (multi model) according to the material property assignment. The subject was an adult male of 23 years old. The DICOM images through the CT of the patient were converted into the 3D image model of a skull using the Mimics (version 10.11, Materialise's interactive Medical Image Control System, Materialise, Belgium). After series of calculating, remeshing, exporting, importing process and volume mesh process was performed, FEA models were produced. FEA models are consisted of maxilla, maxillary central incisor, lateral incisor, canine, periodontal ligaments and lingual traction arm. The boundary conditions fixed the movements of posterior, sagittal and upper part of the model to the directions of X, Y, Z axis respectively. The model was set to be symmetrical to X axis. Through the center of resistance of maxilla complex, a retraction force of 200g was applied horizontally to the occlusal plane. Under this conditions, the initial movements and stress distributions were evaluated by 3D FEA. In the result, the amount of posterior movement was larger in the multi model than in the simple model as well as the amount of vertically rotation. The pattern of the posterior movement in the central incisors and lateral incisors was controlled tipping movement, and the amount was larger than in the canine. But the amount of root movement of the canine was larger than others. The incisor rotated downwardly and the canines upwardly around contact points of lateral incisor and canine in the both models. The values of stress are similar in the both simple and multi model.

• The korean journal of orthodontics
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• v.31 no.4 s.87
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• pp.447-458
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• 2001

The purpose of this study was to evaluate 1) in vivo, the expression of chondroitin 4-sulfate (CH-4S), a structural element of glycosaminoglycans(GAGs), in periodontal tissue during the experimental movement of rat incisors, by labelled streptavidine biotin immunohistochemical staining for CH-4S, 2) In vitro, the expression of CH-4S in cultured human periodontal ligament(PDL) cells supplemented with 10ng/ml of $TGF-{\beta}_1$, 20ng/ml of PDGF-BB, 1ng/ml $TNF-\alpha$, or $1{\mu}g/ml$ LPS by western blot analysis. The results of this study were as follows ; 1. The expression of CH-4S was stronger in pulp, PDL, osteoblasts, osteoclasts and osteocytes in experimental group than in control group, but was rare in dentin, and cementum of experimental groups, regardless of the duration of force application, which was not different from that of control group. 2. In experimental group, the expression of CH-4S in pulp began to increase at 1 day after force application and got to the highest degree at 7 days. After 14 days, the expression in CH-4S immunoreactivity was decreased, and became similar to that of control group at 28 days. 3. The expression of CH-4S in PDL was noted in adjacent to alveolar bone. PDL showed higher intensity of immunolabelling after 1 day of orthodontic tooth movement. And the expression was more stronger in the tension side than that of pressure side of PDL at 1 day, but more stronger in the pressure side than that of tension side of PDL at 4 days. After 7 days, a decrease in CH-4S expression was observed. 4. The expression of CH-4S in alveolar bone got to the highest degree at 4 days, and At 7 days, a decrease in CH-4S expression was observed. 5. PDGF-BB notably raised the expression of CH-4S in the PDL cells at 3 days of cultivation 6. The expression of CH-4S of PDL cells was decreased with the application of $TNF-\alpha$ at 1 day. 7. Admixture of $TGF-{\beta}_1$ and PDGF-BB got more expression of CH-4S in PDL as compared to only $TGF-{\beta}1$ or PDGF-BB. A similar decrease of the expression of CH-4S was observed in the case of application of LPS or $TNF-\alpha$.

• The korean journal of orthodontics
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• v.30 no.4 s.81
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• pp.423-431
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• 2000

Bone remodeling is a complex process regulated by various mediators. Cytokines are known to be associated with the mechanically induced response in orthodontic tooth movement. In particular, IL-$1\beta$ stimulates bone resorption and induces osteoclast proliferation. The purpose of this study was to identify and quantify IL-$1\beta$ in human gingival crevicular fluid(GCF), and to investigate the changes in its level during orthodontic tooth movement. Twelve patients(mean age of 19.2 years) were used as the subjects. An upper canine of each patient haying treatment lot distal movements served as the experimental tooth, whereas the contralateral was used as the control. The GCF of compression and tension side of the experimental teeth and the GCF of mesial side of control teeth was taken from the each subject immediately before activation, and at 1, 24, and 168 hr after initiation tooth movement. IL-$1\beta$ amount was detected by ELISA. The concentration of IL-$1\beta$ was higher in experimental group than in the control group after treatment. Its level was elevated after initiation of tooth movement and it was the highest level at 24 hr in compression side of experimental group. But there was no significant change in control group. The results indicate that the change in IL-$1\beta$ level in GCF is associated with orthodontic tooth movement.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.10a
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• pp.17-17
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• 2003

1960년대 경제개발 5개년 계획의 시작과 함께 우리나라 과학기술의 발전을 위한 투자가 본격화되었고, 과학기술 혁신이 정부정책의 가장 중요한 시책으로 부각되었다. 지난 40 여 년간 우리나라 과학기술은 선진기술의 모방에서 출발하여 효율적으로 단계별 성장을 거치면서 2000 년대에는 세계수준의 지식 및 기술을 창출할 수 있는 토대가 마련되었다. 본 발표에서는 한국과학기술의 현주소와 향후 전망을 분석하여 국내 연구개발의 방향을 조명해 보고자 한다. 1982년 특정연구개발사업을 시작으로 국가적 차원에서 목표설정 및 연구개발 자원을 전략적으로 집결하여 다양한 국가 연구개발 사업들이 수행되어 왔다. 그 후 20여년이 지난 현재 20개 부처에서 200 여개의 국가 연구개발사업이 추진되고 있으며, 이러한 연구개발사업의 성과로서 DRAM, TFT-LCD, CDMA 등 첨단 분야에서 세계 최고 수준의 국제경쟁력을 갖춘 기술들이 다수 확보되었다. 주력 산업인 IT산업, 자동차, 철강, 조선, 섬유 등도 기술혁신에 의한 국제 경쟁력 강화로 수출이 확대되면서 우리 경제의 견인차 역할을 하고 있다 최근 10년간 연구개발 투자규모는 3배 이상 증가하여 2000년 기준으로 세계 8위의 투자규모를 달성하였으며, 민간의 연구개발 투자 비중도 크게 늘어나 민간주도형 연구개발체제로 전환되게 되었다. 2001년에 이르러서는 총연구비 투자규모가 15조 이상으로서 이는 전체 GDP의 ∼3% 에 해당되는 수치이며 선진국 수준에 육박하고 있음을 짐작 할 수 있다. 지식기반사회를 선도하여 국가 경쟁력을 높이기 위해 정부는 연구개발 투자를 계속 확대할 정책을 시도하고 있으며 창의적 과학기술인력의 양성 체제 구축 및 효율적인 활용에도 적극 투자하고 있다. 과학기술부는 과학기술혁신의 중추적 역할을 담당하고 있으며 현재까지 20,000여개이상의 과제를 수행하여 국가경쟁력 강화에 크게 기여하여왔다. 정부는 국내외 과학기술 환경변화가 심한 21세기를 맞이하여 새로운 기회와 도약을 위하여 과학기술 중심국가 건설이라는 새로운 비전을 제시하게 되었다. vision 2025를 통해 2025년까지 21세기 첫 4반세기 동안 과학기술 경쟁력을 세계적인 수준으로 끌어올려 과학기술에 기반을 둔 선진국 진입을 실현하고자 다양한 정책적 대응을 물색하고 있다. 세계 시장규모, 전략적 중요성 등을 토대로 한 10대 산업을 육성하기 위하여 과학기술부는 기술수요조사를 바탕으로 49개 주요기술을 도출하여, 과학기술 일류 국가 실현, 국민소득 2만불 달성이라는 국가적 슬로건을 내걸고 “차세대 성장동력” 창출을 위한 범정부차원의 기획과 연구비의 집중투자를 추진하고 있다.

• The korean journal of orthodontics
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• v.25 no.5 s.52
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• pp.587-592
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• 1995

The purpose of this study was to observe the pattern of bone remodellings in the periodontal ligament of dog, in which experimental tooth movement was performed A control and 5 experimental dogs, one and half year in age, were studied. Light force (50-75g) was applied by placing open-coil spring between left mandibular premolars ; heavy force (250-300g), between right mandibular premolars. Experimental dogs were sacrificed at 12 hours, 1, 3 ,7 and 14 days after force application, respectively. And soft X-ray films were obtained and read on the sectioned periodontal tissue around mandibular premolars. The results were as follows. 1. New bone formation began to be observed in tension side at 7-day and increased at 14-day , No difference was observed between light force group and heavy force group. 2. Bone resorption was observed as a shape of destruction of lamina dura at 3-day and increased gradually at 7-day, 14-day.

• Information and Communications Magazine
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• v.25 no.1
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• pp.5-11
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• 2008

우리 경제의 성장잠재력 저하에 대한 우려가 심화되는 상황에서 국민소득 2만불 시대 견인을 위해 2004년 수립한 IT 산업 발전전략이 IT839이다. 신성장동력 핵심기술 개발 등 IT839전략에 힘입어 세계 최초로 WiBro, DMB 기술개발과 국제표준화에 성공하는 등 IT분야 기술개발을 주도하여, 선진국과의 기술격차가 1년 이상 단축되었으며, 특히, 이동통신 DIV 분야는 미국, 일본 등 선진국 수준으로 경쟁력이 향상되는 성과를 보았다. 한편, 최근 IT를 둘러싸고 있는 환경은 IT를 기반으로한 융복합화 진전, 글로벌화 심화, 인터넷 확산과 웹의 진전이다. 2008년에는 이런 환경변화 속에서 IT산업의 지속적인 성장을 위한 전략을 수립.추진할 계획이다. 무선 융합환경에서 신시장 창출 및 선점, 고부가가치 IT산업의 집중 육성, IT중소기업, 핵심인력 양성 등 경쟁력 향상을 위한 기반 구축도 강화한다. IT R&D 정책은 기초 원천기술분야 R&D 투자비중을 확대하고, IT와 비IT융합 등 융합분야 기술개발 투자도 확대할 것이다. 혁신형 IT 중소기업 육성을 위해 민간 정책협력 네트워크인 IT전문협의회 운영을 개선하고, 중소기업의 원가절감을 위한 공통서비스 확대, 대 중소 기업의 상생협력을 제도화는 등 IT정책 인프라도 고도화한다. 또한, 반도체, 디스플레이 이후의 글로벌 주력품목군으로 IT SoC, u-센서, IT-BT-NT 융합분야 등 3대 핵심분야를 선정하여 집중 육성하고, 부품기업간 협업 활성화를 적극 유도할 것이다. 시장이 원하는 글로벌 수준의 인재양성을 목표로 공학교육인증 확산, IT 융합분야를 중심으로 대학의 R&D 지원도 강화하며, 전공역략을 갖춘 IT 전문인력, 석박사급 핵심 연구개발 인력, IT재직자 교육 등 시장이 원하는 맞춤형 인력양성도 병행 추진한다. 마지막으로 SW산업의 글로벌 경쟁력을 제고하고 신시장 창출을 위해 노력도 강화한다. 조선, 자동차 등 비 IT분야의 SW활용을 확산하기 위한 선도프로젝트를 추진하고, 틈새분야 중 세계적 시장점유율을 갖춘 중소기업 제품에 임베디드SW를 탑재하여 첨단기능을 구현하는 시범사업도 적극 추진할 계획이다.

• The korean journal of orthodontics
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• v.25 no.1 s.48
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• pp.101-110
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• 1995

The purpose of this study was to observe the tissue response to the orthodontic force applied immediately after buccal horizontal subapical osteotomy of maxilla. Five mongrel cats weighing about 2.5 Kg were used for this experiment. The left upper canine and premolar of each cat served as a experimental side and the right ones as a control side. On the experimental side, a 100gm orthodontic force was applied between the upper canine and premolar immediately after the osteotomy. On the control side, the same orthodontic force was applied without the osteotomy. After 7days, the experimental animals were sacrificed. The results were as follows: 1. In the pressure zones of the experimental group, significant increase of osteoclasts and direct resolution along the alveolar bone surface was observed as compared with those of the control group. 2. In the pressure 2ones of the experimental group, a less extensive hyalinized zone was observed than those of the control group. 3. In the pressure zones of both group, no root resorption was found. 4. Tn the tension zones of the experimental group, new bone deposition increased along the alveolar bone surface as compared with those of the control group. In conclusion, the results suggest the possibility that early orthodontic treatment after orthognathic surgery may have some benefits if the stability of the repositioned segment at surgery is secured.

• The korean journal of orthodontics
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• v.25 no.4
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• pp.433-445
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• 1995

Tooth movement, the phenomena and mechanisms of which are still controversial, can be considered as part of the result of the inflammatory processes. The purpose of this study was to examine the activity of macrophage and T-cell, playing important roles in the immune reaction, in the periodontal ligament of dog, in which experimental tooth movement was performed. Six one and half year-old dogs, a control and 5 experimentals, were studied. Light force (50-75g) was applied by placing open-coil spring between left mandibular premolars ; heavy force (250-300g), between right mandibular premolars. Experimental dogs were sacrificed at 12 hours, 1, 3, 7 and 14 days since force application, respectively. And the histologic and the immunohistochemical evaluation on the obtained tissue were performed, using $\alpha$-1-antichymotrypsin and CD3 antibodies. The results were as follows : 1. There were more inflammatory cell infiltrations in heavy force group than in light force group until 3 days. But from 7 dsays on, no difference was not observed between groups ; Such an infiltration was more evident at pressure side than at tension side. 2. Osteoclastic activity at pressure side began to be seen in 12 hours, increasing until 7 days. After then it decreased ; Such an activity was more evident in heavy force group than in light force group. 3. Tearing of periodontal ligament and vascular dilatation at tension side began to be seen in 12 hours, increasing until 3 days. After then it decreased ; Such an observation was more evident in heavy force group than in light force group, but there was no difference between groups in 14 days. 4. $\alpha$-1-antichymotrypsin expression in control group was positive, mainly in sulcular epithelium, but negative in periodontal membrane, pulp, bone cells. 5. $\alpha$-1-antichymotrypsin expression in experimental group was more positive in pressure side than in tension side ; The expression was a little more positive in cervical area of tooth until 3 days, but after 7days, it was more positive in apical area. 6. $\alpha$-1-antichymotrypsin expression in light force group began to be observed in 12 hours and reached to the greatest level in 7 days, after which it decreased ; In heavy force group, it was the greatest in 3 days, after which it decreased. 3 Expression in the periodontium was almost negative.

• Journal of Biosystems Engineering
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• v.31 no.1 s.114
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• pp.9-15
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• 2006

Draft control is key technique in plow control system for automation of implement control system. To make the consistent draft force is an essential factor for preventing the reduction of working efficiency by tractor's slip and also improving the working efficiency. Therefore, the purpose of this study is to develop the draft sensor for draft control of plow and evaluate the usability of the algorithm of draft control system using proportional control valve. The developed draft control system could extract the draft force very well regardless of draft condition, change of setting draft force and response time in the response characteristic test. The maximum draft force at 3-Point linkage was 10,000 N and the deviation of the control system was 125.8 N in steady state condition. The developed control system worked very well with regard to the change of draft force in field and even in soil condition with soil reaction. The results of experiment showed the characteristics of response was sufficient to be used as the implement draft control system for tractor using proportional valve.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2004.11a
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• pp.67-72
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• 2004

최근 건설산업은 공공 및 민간부문의 발주물량 감소가 가시화되고 있으며, 최저가입제에 의한 사업수익율 하락 추세는 향후 건설업 붕괴위기, 건설산업 사양산업화라는 비관적 견해가 떠돌 만큼 건설업 전반이 심각한 위기를 맞고 있다. 정부는 재정 부족으로 인하여 SOC사업의 축소조정이 불가피하지만 국가경제의 악영향 해소와 신속한 경쟁력 회복을 위해 SOC사업에 대한 투자확대와 푹소범위 최소화의 필요성을 인식하고 있으며, 이에 재정부족과 SOC 확충이라는 두가지 문제를 해격하기 위해 민간투자사업이 활성화되고 있는 실정이다. 현재, 정부에 의해 주도되고 있는 민간투자사업의 제도 및 법률의 개정방향은 피간 건설업체가 주도하던 민자사업에 대하여 연기금 및 금융권으로의 전환을 예고하고 있으나, 현실적으로 금융권이 자체적으로 SOC 사업에 대한 투자를 위한 사업 타당성 분석이 어려운 실정이므로 이에 대한 대안으로 SOC 민간투자사업에 대한 노하우를 축적한 건설업체의 SOC 민간투자사업 분야에 아웃소싱 개닐념 도입, 특화하여 효율성을 극대화 시킴으로써 사업의 안정성 확보와 동시에 투자 수익 실현을 통하여 SOC 민간투자 활성화에 견인차 역학을 할 수 있는 전문운영회사의 도입에 대하여 논하고자 한다.