• 대한치과교정학회지
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• 제49권3호
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• pp.140-149
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• 2019

We are currently living in an era where the use of computer-aided design/computer-aided manufacturing has allowed individualized orthodontic treatments, but has also incorporated enhanced digitalized technology that does not permit improvisation. The purpose of this systematic review was to analyze publications that assessed the accuracy and efficiency of the $Invisalign^{(R)}$ system. A systematic review was performed using a search strategy to identify articles that referenced $Invisalign^{(R)}$, which were published between August 2007 and August 2017, and listed in the following databases: MEDLINE, Embase, Cochrane Library, Web of Knowledge, Google Scholar, and LILACS. Additionally, a manual search of clinical trials was performed in scientific journals and other databases. To rate the methodological quality of the articles, a grading system described by the Swedish Council on Technology Assessment in Health Care was used, in combination with the Cochrane tool for risk of bias assessment. We selected 20 articles that met the inclusion criteria and excluded 5 due to excess biases. The level of evidence was high. Although it is possible to treat malocclusions with plastic systems, the results are not as accurate as those achieved by treatment with fixed appliances.

• 한국연안방재학회지
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• 제5권4호
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• pp.193-201
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• 2018

The recent increase in size and speed of ships resulted in the existing maritime routes becoming narrow relative to the size of new ships. At the same time, as the improvement and optimization in marine transportation take place and the construction of structures in seas and harbor improvements pick up speed, there is an increasing probability of marine accidents. Due to these environmental changes, the need to professionally analyze the effect of marine structures on navigation arose to ensure safety of ships and a law was enacted and introduced for the Maritime Traffic Safety Audit (MTSA). In this study, a Qualitative assessment for verifying the effectiveness of MTSA was carried out with case analysis and analysis model in other similar audit scheme. It is expected that an analyzed result for effectiveness of MTSA will be a steppingstone for enhancing the MTSA and keeping maritime traffic safety as its own purpose.

• Nuclear Engineering and Technology
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• 제54권3호
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• pp.926-939
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• 2022

The area of this study will cover the location-wise seismic response variation of an electrical cabinet in nuclear power point (NPP) based on classical reliability analysis. The location-based seismic ground motion (GM) selection is carried out with the help of probabilistic seismic hazard analysis using PSHRisktool, where the variation of reliability analysis can be understood from the relation between the reliability index and intensity measure. Two different approaches such as the first-order second moment method (FOSM) and Monte Carlo Simulation (MCS) are helped to evaluate and compare the reliability assessment of the cabinet. The cabinet is modeled with material uncertainty utilizing Steel01 as the material model and the fiber section modeling approach is considered to characterize the section's nonlinear reaction behavior. To verify the modal frequency, this study compares the FEM result with recorded data using Least-Squares Complex Exponential (LSCE) method from the impact hammer test. In spite of a few investigations, the main novelty of this study is to introduce the reader to check and compare the seismic reliability assessment variation in different seismic locations and for different earthquake levels. Alongside, the betterment can be found by comparing the result between two considered reliability estimation methods.

• International Journal of Advanced Culture Technology
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• 제11권3호
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• pp.346-357
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• 2023

The purpose of this study is to suggest improvement plans for prevention regulations by reflecting the toxicity, fire and explosion effects of hazardous materials factories and surrounding areas using an off-site consequence assessment program. Regarding the effects of the hydrogen cyanide leak accident, which is the 1st petroleum of the 4th class flammable liquid, Areal Locations of Hazardous Atmospheres (ALOHA) program was used to compare and analyze the extent of damage effects for toxicity, overpressure, and radiation. As a result, the toxicity was analyzed to exceed 5km in the area with Acute exposure guideline level (AEGL)-2 concentration or higher, the overpressure was 103m in the range of 1 psi or more, and the radiant heat was analyzed to be 724m in the range of 2kw/m² or more. Toxicity and radiation affected the area outside the hazardous material storage area, but the overpressure was limited to the inside of the hazardous material storage area. Therefore, we propose to improve the safety management of hazardous materials by conducting a risk assessment for hazardous materials and reflecting the results in internal and external emergency response plans to prepare prevention regulations.

• 인간식물환경학회지
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• 제22권2호
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• pp.167-180
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• 2019

This study was conducted to investigate effective ways to meet social and cultural interest in and needs of gardens and gardening. A total of 191 respondents who answered they were living in Gyeongnam region in the questionnaire were selected: 102 (53.4%) were males and 89 (46.6%) were females. In frequency of garden visits, 45% of the respondents answered they visited gardens once a year. Their preferred companion was family (43.6%), followed by friends/colleagues (24.3%). Their important motives of garden visits included admiration of gardens' scenery and ambience, pleasure in being outdoors, relaxing mentally and physically, and appreciation of plants. Relatively less important motives included understanding or educating about nature and environmental conservation, and interest in garden design and horticulture techniques. In the overall assessment of gardens and gardening, the quality of the establishment, management and operation of botanic gardens and arboreta in Gyeongnam region scored 3.32 scale, which was close to the level of 'fair.' Also, the respondents agreed at 3.91 scale that it was necessary to improve the garden creation, gardening, and garden culture. Meanwhile, many people in Gyeongnam region did not clearly understand differences between garden and public park, also had a very obscure perception of public garden. The results of importance-performance analysis (IPA) indicated that it is necessary to concentrate on directing and developing some programs such as admiration of beautiful and exotic plants, and education on garden culture including garden making and horticultural techniques.

• 전자통신동향분석
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• 제38권6호
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• pp.31-40
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• 2023

Given recent accidents involving autonomous vehicles, driver monitoring technology related to the transition of control in autonomous vehicles is gaining prominence. Driver status monitoring systems recognize the driver's level of alertness and identify possible impairments in the driving ability owing to conditions including drowsiness and distraction. In autonomous vehicles, predictive factors for the transition to manual driving should also be included. During traditional human driving, monitoring the driver's status is relatively straightforward owing to the consistency of crucial cues, such as the driver's location, head orientation, gaze direction, and hand placement. However, monitoring becomes more challenging during autonomous driving because of the absence of direct manual control and the driver's engagement in other activities, which may obscure the accurate assessment of the driver's readiness to intervene. Hence, safety-ensuring technology must be balanced with user experience in autonomous driving. We explore relevant global and domestic regulations, the new car assessment program, and related standards to extract requirements for driver status monitoring. This kind of monitoring can both enhance the autonomous driving performance and contribute to the overall safety of autonomous vehicles on the road.

• 벤처창업연구
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• 제16권6호
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• pp.157-175
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• 2021

본 연구는 기술보증기금이 2017년부터 2019년까지 기술평가를 통하여 보증 지원한 기술 중소기업 중 3,214개 기업을 대상으로 4차 산업혁명 기업과 일반 중소기업으로 구분한 후 경영 특성이 고성장 기업 결정에 미치는 영향을 실증 분석하였다. 고성장 기업 판단은 OECD(2007)의 정의를 적용하여 최근 2년간 매출액 증가율이 연간 평균 20% 이상인 기업이다. 표본 대상의 두집단이 비정규분포를 따르고 있어 Mann-Whitney U test 비모수 검증으로 평균치 차이 분석을 하였다. 또한 정규성 가정이 덜 엄격한 이변량 로지스틱 회귀분석을 실시하였다. 독립변수는 대표자 역량, 인적자본 역량, 기술혁신 역량, 기본 특성, 지역더미, 기술수준 더미이다. 이에 대응하는 하위변수는 대표자 학력, 대표자 동업종 경험 수준, 상시 종업원, 연구 인력, 지식 재산권 수, 연구개발 투자금액, 기업 업력, 총자산, 지역_수도권, 지역_중부권, 기술수준_첨단기술, 기술수준_중기술이다. 분석결과, 4차 산업혁명 기업은 대표자 동업종 경험수준, 상시종업원, 기업업력, 총자산, 기술수준_첨단기술의 연구가설이 지지되었다. 일반 중소기업은 대표자 동업종 경험수준, 연구인력, 총자산, 지역_수도권의 연구가설이 지지되었다.

• Smart Structures and Systems
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• 제20권2호
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• pp.139-150
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• 2017

The structural strain plays a significant role in structural condition assessment of in-service bridges in terms of structural bearing capacity, structural reliability level and entire safety redundancy. Therefore, it has been one of the most important parameters concerned by researchers and engineers engaged in structural health monitoring (SHM) practices. In this paper, an SHM system instrumented on the Jiubao Bridge located in Hangzhou, China is firstly introduced. This system involves nine subsystems and has been continuously operated for five years since 2012. As part of the SHM system, a total of 166 fiber Bragg grating (FBG) strain sensors are installed on the bridge to measure the dynamic strain responses of key structural components. Based on the strain monitoring data acquired in recent two years, the strain-based structural condition assessment of the Jiubao Bridge is carried out. The wavelet multi-resolution algorithm is applied to separate the temperature effect from the raw strain data. The obtained strain data under the normal traffic and wind condition and under the typhoon condition are examined for structural safety evaluation. The structural condition rating of the bridge in accordance with the AASHTO specification for condition evaluation and load and resistance factor rating of highway bridges is performed by use of the processed strain data in combination with finite element analysis. The analysis framework presented in this study can be used as a reference for facilitating the assessment, inspection and maintenance activities of in-service bridges instrumented with long-term SHM system.

• Nuclear Engineering and Technology
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• 제48권6호
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• pp.1368-1375
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• 2016

A radiological safety assessment study was performed for the transportation of low level radioactive wastes which are temporarily stored in Korea Atomic Energy Research Institute (KAERI), Daejeon, Korea. We considered two kinds of wastes: (1) operation wastes generated from the routine operation of facilities; and (2) decommissioning wastes generated from the decommissioning of a research reactor in KAERI. The important part of the radiological safety assessment is related to the exposure dose assessment for the incidentfree (normal) transportation of wastes, i.e., the radiation exposure of transport personnel, radiation workers for loading and unloading of radioactive waste drums, and the general public. The effective doses were estimated based on the detailed information on the transportation plan and on the radiological characteristics of waste packages. We also estimated radiological risks and the effective doses for the general public resulting from accidents such as an impact and a fire caused by the impact during the transportation. According to the results, the effective doses for transport personnel, radiation workers, and the general public are far below the regulatory limits. Therefore, we can secure safety from the viewpoint of radiological safety for all situations during the transportation of radioactive wastes which have been stored temporarily in KAERI.

• Nuclear Engineering and Technology
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• 제50권8호
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• pp.1324-1329
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• 2018

This study presents a practical application of complementary safety indicators, which can be applied in a safety assessment of a radioactive waste repository by excluding a biosphere simulation and comparing the artificial radiation originating from the repository with the background natural radiation. Complementary safety indicators (radiotoxicity flux from geosphere and radiotoxicity concentration in seawater) were applied in the safety assessment of a rock-cavern type low and intermediate level radioactive waste (LILW) repository in the Republic of Korea. The natural radionuclide ($^{40}K$, $^{226,228}Ra$, $^{232}Th$, and $^{234,235,238}U$) concentrations in the groundwater and seawater at the Gyeongju LILW repository site were measured. Based on the analyzed concentrations of natural radionuclides, the levels of natural radiation were determined to be $8.6{\times}10^{-5}$ - $8.0{\times}10^{-4}Sv/m^2/yr$ and $6.95{\times}10^{-5}Sv/m^3$ for radiotoxicity flux from the geosphere and radiotoxicity concentration in seawater, respectively. From simulation results obtained using a Goldsim-based safety assessment model, it was determined that the radiotoxicity of radionuclides released from the repository is lower than that of the natural radionuclides inherently present in the natural waters. The applicability of the complementary safety indicators to the safety case was discussed with regard to reduction of the uncertainty associated with biosphere simulations, and communication with the public.