• The korean journal of orthodontics
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• v.34 no.6 s.107
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• pp.497-505
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• 2004

The purpose of this study was to evaluate the post-retention stability of the lower incisor axis in Class II division 2 malocclusions. The dental casts and lateral cephalograms from before (T1) and after (T2) orthodontic treatment and long-term post-retention (T3) in 62 Class II division 2 malocclusion cases were included in this study. After several linear and angular measurements at each time were taken, the significance in the amount of change of the lower incisor axis for each gender and extraction versus non-extraction was evaluated. The results showed that the lower incisors that inclined labially during treatment were unstable and relapsed to the original lingual position in Class II division 2 malocclusions (p<0.001). There was no significant difference between extraction and non-extraction groups for the amount of lingual relapse of the lower incisors (p>0.05). There was no significant difference between male and female groups for the axial change of the lower incisors (p>0.05). As a result of multiple regression analysis, the cephalometric measurement best predicting the lower incisor position to the A-Pog line post-retention was pre-treatment L1-Apog(mm) and pre-treatment SNGoMe$(^{\circ})$. Because of the instability of labially inclined lower incisors after orthodontic treatment, the treatment goal should be the pre-treatment incisor axial position.

• Journal of the Korean GEO-environmental Society
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• v.23 no.8
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• pp.23-28
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• 2022

In Korea, 70% of the land is mountainous and structures occupy a high proportion in railway and road construction. In particular, in recent years, the construction of high-speed railways and highways for high-speed driving is rapidly increasing. At the same time, the construction of tunnels is also increasing. The number of tunnel construction cases in which long-term deformation occurs after tunnel excavation is completed is increasing. The stability of these tunnel structures depends entirely on the characteristics of the rock surrounding the tunnel excavation. In the case of pyroclastic rock, which is the subject of this study, it is generally vulnerable to weathering and has a characteristic that its strength decreases over a long period of time. Tunnel design and construction planning considering the strength characteristics of pyroclastic rocks are essential. This study analyzed the cases of over-deformation that occurred at the tunnel site in the pyroclastic section. Based on this study, a plan for tunnel design and construction management in an area where pyroclastic rock exist in the future is presented.

• Journal of Dental Rehabilitation and Applied Science
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• v.38 no.2
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• pp.97-109
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• 2022

Purpose: This study aims to investigate the risk indicators contributing to implant failure, and analyze the relationship between risk indicators and marginal bone loss (MBL) through long-term follow-up over 3 years. Materials and Methods: From 2003 to 2017, patients' medical charts with a history of dental implant surgery at Chonnam National University Dental Hospital were reviewed retrospectively. The patient's demographic variables, and clinical variables were recorded. Periapical radiographs were used to evaluated the changes in MBL around implants. And we analyzed implant survival rates. Multiple regression analysis with backward elimination was conducted to correlate the patient's clinical variables and implant failure and Pearson correlation analysis was performed to the correlated between implant long-term survival rates and MBL and initial stability. Results: In multiple regression analysis, there was a statistically significant negative correlation between abutment connection type (β = -.189, P < .05), with or without SPT (β = -.163, P < .05), diabetes (β = -.164, P < .05), osteoporosis (β = -.211, P < .05) and MBL. Anticoagulant medication influenced the long-term success rate of implants. PTV values at the second implant surgery showed a statistically significant negative correlation with long-term implant survival (P < .05). Conclusion: For the long-term success of the implant, the appropriate abutment connection type must be selected and the periodic SPT is recommended. Systemic diseases such as diabetes and osteoporosis and anticoagulant medication should be considered. Furthermore, since high PTV at the second implant surgery correlated with the long-term survival rates of the implant, initial stability should be carefully considered before undergoing the prosthetic procedure.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.997-1001
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• 2009

GIS 기반의 HEC-HMS를 이용하여 유량자료가 있는 소하천인 정자천 유역을 대상으로 장기 강우 유출 분석을 하였다. 일반적으로 홍수량 산정은 단기해석으로 분석하나 평 갈수기와 홍수기 때의 하천 유황이 다르기 때문에 매개변수가 불일치할 것이라 생각되고, 이에 대한 보정이 필요한지 판단이 필요하다. 이를 위해 장기 연속모의를 통하여 매개변수의 보정 필요성을 검토하였다. 연구는 수치지도를 조합하여 ARC-VIEW로부터 Map파일 및 Basin파일을 생성하였고, 토지이용도와 토양도를 ARC-VIEW를 이용하여 CN value를 추출하였다. 계산조건중 손실량 산정방법은 SCS Curve Number법으로 하였고, 단위도 방법은 Clark UH법, 하도추적방법은 Muskingum방법, 기저유량산정방법은 Constant monthly로 설정하였다. 유역면적, 도달시간자료, 저류상수 값 등의 추출은 GIS기법을 이용하여 추출하였다. HEC-HMS의 장기 연속모의(Continuous Simulation)로 얻어진 Element Graph를 보면 대략적인 형태가 일치하나 2006년도에 대한 모의에서는 홍수기의 결과만 일치하는 것으로 보이고, 2007년도에 대한 모의에서는 평 갈수기와 홍수기의 그래프 형태가 유사하게 나타났다. 실측 유량보다 유량 값이 약간 크게 산출되어 홍수량 산정에서 볼 때 안정성에 무리가 없다고 판단되지만, 평 갈수기 기간에서 볼 때 연마다 하천의 매개변수가 일치하지 않는다고 생각되며, 홍수 후 유역의 변화로 매개변수가 변화한 것이라 생각된다. 향후 정자천유역의 보다 많은 강우사상과 실측유량을 통해 HEC-HMS의 유출량을 비교 분석하면 보다 더 정확한 해석이 가능할 것이며, 홍수가 빈번한 지역의 경우 유수지의 검토와 저수지의 시간당 방류량을 알 수 있다면 오차의 범위를 줄일 수 있다고 생각된다. 더 나아가 우리나라에 적합한 매개변수와 GIS 프로그램이 개발된다면 보다 쉽고 정확한 해석이 가능할 것이라고 생각된다.

• Journal of Korean Society of Archives and Records Management
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• v.19 no.4
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• pp.1-33
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• 2019

The key to the long-term preservation of electronic records is the long-term retention of the bitstream that contains the original functional attributes and appearances of the electronic records that were originally created and utilized. Considering economic and technical aspects, most of the major domestic and foreign archives have adopted a migration strategy that allows conversion to a new format depending on the stability and reliability of the format containing the original bitstream. However, as the type of electronic records varies and its scope continuously expands, several problems arise if a single migration strategy is observed. Therefore, the applicability of the emulation strategy is examined in this paper to reproduce the system and application environment where electronic records are created and utilized. As such, electronic records can be maintained without any changes in the bitstream by utilizing cloud computing technology.

• Proceedings of the KSLP Conference
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• 1996.11a
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• pp.88-88
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• 1996

본 연구목적은 한국어판 실어증감별진단검사를 이용하여 2회 이상 경과를 검토할 수 있었던 Broca실어의 3증례에 있어서의 개선경과를 초회평가시의 실어증 중등도가 거의 같은 일본의 장기 관찰예와 비교하여 장애 pattern의 검출 및 개선경과의 추적에 있어서의 한국판 실어증 감별진단검사의 유효성을 검토하였다. 그 결과, 신경학적으로 안정되어있는 실어증환자의 경우 중증도별로 보면, 언어과정 전반의 득점 profile은 유사성이 높았으며, 치료경과에 양국어의 일반성과 특수성이라고 하는 면에서는 금후 한층 더 상세한 토의가 요구되었다.

• The Journal of Engineering Geology
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• v.13 no.2
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• pp.157-170
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• 2003

This study is performed to investigate the cause of slope failure and to suggest suitable stabilization methods for the failed rock slopes. The slope which is located along the national highway between Maesan and Kakok in Dangjin-gun failed during the construction of roads. Site investigation, drilling program, field measurements, rainfall records, and stability analyses are used to investigate the cause of the slope failure. The problem determining the cut-slope angle based on the existing design manual for the construction of roads is reviewed based on the case history given in this paper. If weakness layer and geological structures such as folds and faults are developed in a slope, slope failure is possible even though the direction of slope and the direction of discontinuities depart more than $30^{\circ}$.

• Journal of the Korean GEO-environmental Society
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• v.17 no.11
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• pp.23-33
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• 2016

This study evaluated the stability and deformation subsea foundation after implementation of the contaminant isolation method by covering the contaminated materials using Zeolite and sands under subsea condition. The appropriate contaminant adsorption materials used in this study was selected as Zeolite based on the existing research results due to its efficiency. Safety (or stability) was evaluated by calculation and to analyze deformation after completing the contaminant isolation method. The minimum safety factors from slope stability analyses results were 30.1 and 11.2 depending on subsea submerged conditions and the amount of the maximum primary consolidation settlement from consolidation analysis results was 209.2 mm. In addition, change of consolidation amount with increasing consolidation time was evaluated based on consolidation degree.

• Journal of the Korean Vacuum Society
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• v.11 no.4
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• pp.189-193
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• 2002

We have developed a characteristics evaluating system for low vacuum gauges with a project of basis of vacuum technology construction. By using this system, we also performed a characteristics evaluation as to the accuracy, linearity, repeatability, gas sensitivity, and long-term stability of thermal conductivity gauges.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.223-224
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• 2010

As the demand on nuclear power is increasing, it is required to investigate for concrete durability in nuclear structure. However, the inspected datas for durability are insufficient in nuclear structure. The test specimens are prepared according to the mix design that has been used in the domestic nuclear structure. And, the characteristics of durability are investigated for the specimens. It will be needed to estimate the long-term durability.