• 대한치과교정학회지
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• 제53권2호
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• pp.106-115
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• 2023

Objective: To evaluate the null hypothesis that there is no difference in a set of clinical predictors of potentially impacted canines between low-risk patients with and without displaced canines. Methods: The normal canine position group consisted of 30 patients with 60 normally erupting canines ranked in sector I (age, 9.30 ± 0.94 years). The displaced canine group comprised 30 patients with 41 potentially impacted canines ranked in sectors II to IV (age, 9.46 ± 0.78 years). Maxillary lateral incisor crown angulation, inclination, rotation, width, height, and shape, as well as palatal depth, arch length, width, and perimeter composed a set of clinical predictors, which were evaluated on digital dental casts. Statistical analyses consisted of group comparisons and variable correlations (p < 0.05). Results: There was a significant association between sex and mesially displaced canines. Unilateral canine displacement was more prevalent than bilateral displacement. The crown of the maxillary lateral incisors was significantly angulated more mesially and rotated mesiolabially in low-risk patients with displaced canines, who also had a shallower palate and shorter anterior dental arch length. Lateral incisor crown angulation and rotation, as well as palatal depth and arch length, were significantly correlated with the canine displacement severity. Conclusions: The null hypothesis was rejected. Maxillary lateral incisor angulation inconsistent with the "ugly duckling" stage as well as a shallow palate and short arch length are clinical predictors that can significantly contribute to the early screening of ectopic canines in low-risk patients.

• 디지털융복합연구
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• 제20권3호
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• pp.75-83
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• 2022

OECD 국가 중 보행자 사망 비율이 가장 높은 대한민국은 보행자 중심으로 법령이 제정하면서 안전한 보행환경 개선을 위해 노력하고 있다. 이 연구는 노인 인구와 학원이 밀도가 높은 대구광역시를 대상으로 보행자 교통사고 클러스터를 포아송분포를 이용한 스캔통계량으로 파악하고자 한다. 어린이와 노인에 관한 교통사고의 대중 인식을 수집하여 워드클라우드로 살펴본 결과 어린이는 정부와 기업인의 캠페인을 중심으로 노출되고 있고, 노인은 사고감소를 위한 정책연구를 중심으로 노출되고 있었다. 어린이 보행자 교통사고의 상대적 위험성은 공단이 많은 평리·내당·용산동에서 높았고, 학원 밀집도가 높은 만촌·봉무·범어동에서 낮았다. 노인 보행자 교통사고의 상대적 위험성은 도심에 가까운 용산·죽전·두류·내당동에서 높았고, 범어·삼덕·팔공·봉무동에서 낮았다. 대구광역시 내당동과 용산동은 어린이와 노인 보행사고 위험성이 높아 보행 안전 취약지역으로 파악되었다. 이는 스캔통계량이 교통사고 위험 지역 탐색에 효과적임을 의미한다.

• 대한토목학회논문집
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• 제30권6C호
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• pp.219-229
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• 2010

우리 나라는 산지가 국토 면적의 약 70%를 차지하고 있기 때문에 장마나 태풍 시 집중 강우에 의하여 다수의 사면 붕괴가 발생하고 있으며, 이러한 사면 붕괴로 인해 많은 인명과 재산피해가 발생되고 있다. 이러한 상황하에서 사면 붕괴로 인한 피해를 경감시키기 위해서는 광범위한 지역에 걸쳐 분포되어 있는 사면을 대상으로 붕괴가 예상되는 위험한 사면부를 추출하여 방재 대책을 강구할 필요성이 있으며, 이를 위해서는 사면의 안정성 또는 위험도의 정량적 평가가 선행되어야 한다. 그러나 국내에는 아직까지 광역의 수많은 사면을 대상으로 강우와 지형적 요인 및 토질공학적 요인을 고려한 위험도 예측모델이 구축되어 있지 않은 실정이다. 따라서, 본 연구에서는 유역 내 지하수위의 시간 변화를 구하는 집수모델과 무한사면의 안정해석모델을 조합한 해석기법을 제안하고, 이를 이용한 해석 사례를 소개하고자 한다.

• 자원ㆍ환경경제연구
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• 제16권3호
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• pp.683-699
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• 2007

이 연구는 선택실험법(CE)을 이용하여 다속성 사망 위험 감소와 관련된 선택들로부터 확률적 인간생명 가치(VSL)를 추정하였다. 사망 위험의 네 가지 속성들(사망 원인, 사망위험의 자발성, 사망 시기, 사망 위험 감소의 크기)을 이용하여 선택 대안들의 집합을 설계하였다. 다항 로짓모형의 추정 결과는 10년 동안 1/1,000의 사망 위험을 감소하기 위해 연간 27,930원, 성인의 사망 위험 감소를 위해 연간 116,773원, 자발적 사망 위험 감소를 위해 연간 97,682원, 비자발적 사망 위험 감소를 위해 연간 77,234원을 지불하려고 하였다. 이로부터 얻어진 다양한 확률적 인간생명가치로는 청소년 이하(18세 미만)인 경우 11.65~13.67억 원, 성인(18~59세)은 16.31~18.33억 원, 노인(60세 이상)의 경우는 11.28~13.30억 원으로 추정되었다.

• 전자공학회논문지
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• 제50권12호
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• pp.247-253
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• 2013

본 연구의 목적은 Direct DR(Digital Radiography), Indirect DR, I.I(Image Intensifier) DR에서 X선 광자 검출 방식에 따른 선량측정 및 획득된 영상을 정량적이고 객관적인 측정을 통해 DR System을 비교 평가 하는 것이다. Rando phantom을 사용하여 입사표면선량을 측정하였으며, 측정된 입사표면선량 값을 통해 PCXMC 프로그램을 사용하여 유효선량과 방사선 조사로 인한 위험을 평가하였다. 21cm 아크릴 phantom을 사용하여 SNR(Signal to Noise Ratio), NPS(Noise Power Spectrum), CNR(Contrast to Noise Ratio)을 측정하였으며, 측정값은 통계학적 분석기법을 사용하여 유의성을 평가하였다. 입사표면선량, 주요장기선량, 유효선량 모두 direct DR이 가장 낮게 측정되었으며, direct DR 선량을 기준으로 I.I type DR은 약 1.3배, indirect DR은 약 2.4배 높은 선량 비율로 측정되었다. 방사선량에 따른 위험도 역시 동일한 비율로 측정되었다. SNR 측정 결과 direct DR측정값을 기준으로 I.I DR은 약 7.25배, indirect DR이 약 1.48배 낮은 비율로 측정되었다. CNR 측정 결과 direct DR 측정값을 기준으로 I.I DR은 약 1.16배 높고, indirect DR이 약 0.87배 낮은 비율로 측정되었다. 따라서 a-selenium 검출소자를 사용하여 X선 광자를 검출하는 방식인 direct DR은 적은 선량으로 우수한 화질의 영상을 구현함으로써 선량에 민감한 소아나 생식선이 포함된 검사 등에 유용할 것으로 사료된다. 또한 많은 진단 정보를 위한 영상 평가가 요구되는 경우에는 indirect DR이 유용할 것으로 판단된다.

• Journal of Information Technology Applications and Management
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• 제26권6호
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• pp.47-63
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• 2019

The volatility of major crypto currencies was examined and they are diagnosed whether they have a systematic risk or not, by estimating market beta representing systematic risk using GARCH( Generalized Auto Regressive Conditional Heteroskedastieity) model. First, the empirical results showed that their prices are very volatile over time because of the existence of ARCH and GARCH effects. Second, in terms of efficiency, asymmetric GJR model was estimated to be the most appropriate model because the standard error of a market beta was less than that of the OLS model and GARCH model. Third, the estimated market beta of Bitcoin using GJR model was less than 1 at 0.8791, showing that there is no systematic risk. However, unlike OLS model, the market beta of Ethereum and Ripple was estimated at 1.0581 and 1.1222, showing that there is systematic risk. This result shows that bitcoin is less dangerous than Ripple and Ethereum, and ripple is the most dangerous of all three crypto currencies. Finally, the major cryptocurrency found that the negative impact caused greater variability than the positive impact, causing bad news to fluctuate more than good news, and therefore good news and bad news had a different effect on the variability.

• 한국의료질향상학회지
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• 제22권2호
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• pp.27-40
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• 2016

Purpose: Globally, falls are a major public health problem. The study aimed to evaluate the predictive validity of the Timed Up and Go test (TUGT) as a screening tool for fall risk. Methods: An electronic search was performed Medline, EMBASE, CINAHL, Cochran Library, KoreaMed and the National Digital Science Library and other databases, using the following keywords: 'fall', 'fall risk assessment', 'fall screening', 'mobility scale', and 'risk assessment tool'. The QUADAS-II was applied to assess the internal validity of the diagnostic studies. Thirteen studies were analyzed using meta-analysis with MetaDisc 1.4. Results: The selected 13 studies reporting predictive validity of TUGT of fall risks were meta-analyzed with a sample size of 1004 with high methodological quality. Overall predictive validity of TGUT was as follows. The pooled sensitivity 0.72 (95% confidence interval [CI]: 0.67-0.77), pooled specificity 0.58 (95% CI: 0.54-0.63) and sROC AUC was 0.75 respectively. Heterogeneity among studies was a moderate level in sensitivity. Conclusion: The TGUT's predictive validity for fall risk is at a moderate level. Although there is a limit to interpret the results for heterogeneity between the literature, TGUT is an appropriate tool to apply to all patients at a potential risk of accidental fall in a hospital or long-term care facility.

• Imaging Science in Dentistry
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• 제46권3호
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• pp.167-171
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• 2016

Purpose: Obstructive sleep apnea (OSA) is a common medical disorder with serious complications if untreated. Dentists play a vital role in the early diagnosis of this condition, thereby improving patients' prognoses. The purpose of this study was to identify patients with a high risk of OSA using simple cephalometric measurements in patients receiving routine dental care. Materials and Methods: The present study was conducted on 206 patients divided into a high-risk group and a control group after answering the Berlin questionnaire. Cephalometric analysis of a digital cephalogram was performed to measure the upper airway diameter (UAD) and mandibular-to-hyoid bone distance (MP-H) by 2 observers at 2 different times. Results: Among 206 patients, 93 (45%) were included in the high-risk group and 113 (55%) were in the control group. No significant difference was present between the groups with regard to gender, and the patients ranged in age from 18 to 65 years. The UAD measurements in the high-risk group were significantly lower than in the control group, and the MP-H measurements were significantly higher in the high-risk group than in the control group. The UAD was lower in middle-aged patients in both groups. Conclusion: Our study found that the UAD was lower in individuals with a high risk of OSA. Also, we found that middle-aged individuals of both genders were more likely to develop OSA. Dentists play a vital role in diagnosing patients at a high risk for OSA via thorough clinical examinations, risk factor analyses, and simple cephalometric analyses.

• Coupled systems mechanics
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• 제11권6호
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• pp.505-524
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• 2022

Floods represent extreme hydrological phenomena that affect populations, environment, social, political, and ecological systems. After the catastrophic floods that have hit Europe and the World in recent decades, the flood problem has become more current. At the EU level, a legal framework has been put in place with the entry into force of Directive 2007/60/EC on Flood Risk Assessment and Management (Flood Directive). Two years after the entry into force of the Floods Directive, Bosnia and Herzegovina (B&H), has adopted a Regulation on the types and content of water protection plans, which takes key steps and activities under the Floods Directive. The "Methodology for developing flood hazard and risk maps" (Methodology) was developed for the territory of Bosnia and Herzegovina, following the methodology used in the majority of EU member states, but with certain modifications to the country's characteristics. Accordingly, activities for the preparation of the Preliminary Flood Risk Assessment for each river basin district were completed in 2015 for the territory of Bosnia and Herzegovina. Activities on the production of hazard maps and flood risk maps are in progress. The results of probable climate change impact model forecasts should be included in the preparation of the Flood Risk Management Plans, which is the subsequent phase of implementing the Flood Directive. By the foregoing, the paper will give an example of the development of the hydrodynamic model of the Zujevina River, as well as the development of hazard and risk maps. Hazard and risk maps have been prepared for medium probability floods of 1/100 as well as for high probability floods of 1/20. The results of LiDAR (Light Detection and Ranging) recording were used to create a digital terrain model (DMR). It was noticed that there are big differences between the flood maps obtained by recording LiDAR techniques in relation to the previous flood maps obtained using georeferenced topographic maps. Particular attention is given to explaining the Methodology applied in Bosnia and Herzegovina.

• 한국산업융합학회 논문집
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• 제27권1호
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• pp.25-37
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• 2024

The objective of this study was to create intelligent rail robots that are optimized for facility management and implement digital twin systems for smart road tunnel management. An autonomous surveillance system is formed by combining the sensing platform consisting of railing robots, fixed cameras and environmental detection sensors with the digital twin data platform technology for tunnel monitoring and early fire suppression. In order to develop mobile rail robots for fire extinguishing, we also designed and manufactured robots for extinguishing & monitoring and fire extinguishing devices, and then we examined the optimization of all parts. Our next step was to build a digital twin for road tunnel management by developing continuous image display system and implementing 3D modeling. After constructing prototypes, we attempted simulations by configuring abnormal symptom scenarios, such as vehicles fires. This study's proposal proposes high-accuracy risk prediction services that will enable intelligent management of risks in the tunnel with early response at each stage, using the data collected from the intelligent rail robots and digital twin systems.