• Journal of Chest Surgery
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• v.55 no.3
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• pp.189-196
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• 2022

Background: This study investigated the predictive value of the frailty index calculated using laboratory data and vital signs (FI-L) in patients who underwent coronary artery bypass grafting (CABG). Methods: This study included 508 patients (age 67.3±9.7 years, male 78.0%) who underwent CABG between 2018 and 2021. The FI-L, which estimates patients' frailty based on laboratory data and vital signs, was calculated as the ratio of variables outside the normal range for 32 preoperative parameters. The primary endpoints were operative and medium-term all-cause mortality. The secondary endpoints were early postoperative complications and major adverse cardiac and cerebrovascular events (MACCEs). Results: The mean FI-L was 20.9%±10.9%. The early mortality rate was 1.6% (n=8). Postoperative complications were atrial fibrillation (n=148, 29.1%), respiratory complications (n=38, 7.5%), and acute kidney injury (n=15, 3.0%). The 1- and 3-year survival rates were 96.0% and 88.7%, and the 1- and 3-year cumulative incidence rates of MACCEs were 4.87% and 8.98%. In multivariable analyses, the FI-L showed statistically significant associations with medium-term all-cause mortality (hazard ratio [HR], 1.042; 95% confidence interval [CI], 1.010-1.076), MACCEs (subdistribution HR, 1.054; 95% CI, 1.030-1.078), atrial fibrillation (odds ratio [OR], 1.02; 95% CI, 1.002-1.039), acute kidney injury (OR, 1.06; 95% CI, 1.014-1.108), and re-operation for bleeding (OR, 1.09; 95% CI, 1.032-1.152). The minimal p-value approach showed that 32% was the best cutoff for the FI-L as a predictor of all-cause mortality post-CABG. Conclusion: The FI-L was a significant prognostic factor related to all-cause mortality and postoperative complications in patients who underwent CABG.

• Tuberculosis and Respiratory Diseases
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• v.86 no.4
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• pp.272-283
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• 2023

Background: In patients with chronic obstructive pulmonary disease (COPD), decreased muscle mass is a frequently encountered comorbidity in clinical practice. However, the evaluation of muscle mass in patients with COPD in real-world practice is rare. Methods: We retrospectively reviewed the electronic medical records of all patients with COPD who underwent bioelectrical impedance analysis at least once between January 2011 and December 2021 in three hospitals. Then, we analyzed the performance rate of muscle mass measurement in the patients and the correlation between muscle mass, clinical parameters, and COPD prognosis. Results: Among the 24,502 patients with COPD, only 270 (1.1%) underwent muscle mass measurements. The total skeletal muscle mass index was significantly correlated with albumin, alanine transaminase, and creatinine to cystatin C ratio in patients with COPD (r=0.1614, p=0.011; r=0.2112, p=0.001; and r=0.3671, p=0.001, respectively). Acute exacerbation of COPD (AE COPD) was significantly correlated with muscle mass, especially the truncal skeletal muscle mass index (TSMI) in males (r=-0.196, p=0.007). In the multivariate analysis, TSMI and cystatin C were significant risk factors for AE COPD (hazard ratio, 0.200 [95% confidence interval, CI, 0.048 to 0.838] and 4.990 [95% CI, 1.070 to 23.278], respectively). Conclusion: Low muscle mass negatively affects the clinical outcomes in patients with COPD. Despite its clinical significance, muscle mass measurement is performed in a small proportion of patients with COPD. Therefore, protocols and guidelines for the screening of sarcopenia in patients with COPD should be established.

• Annals of Hepato-Biliary-Pancreatic Surgery
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• v.28 no.2
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• pp.248-261
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• 2024

Backgrounds/Aims: This study aimed to investigate patterns and factors affecting recurrence after curative resection for pancreatic ductal adenocarcinoma (PDAC). Methods: Consecutive patients who underwent curative resection for PDAC (2011-21) and consented to data and tissue collection (Barts Pancreas Tissue Bank) were followed up until May 2023. Clinico-pathological variables were analysed using Cox proportional hazards model. Results: Of 91 people (42 males [46%]; median age, 71 years [range, 43-86 years]) with a median follow-up of 51 months (95% confidence intervals [CIs], 40-61 months), the recurrence rate was 72.5% (n = 66; 12 loco-regional alone, 11 liver alone, 5 lung alone, 3 peritoneal alone, 29 simultaneous loco-regional and distant metastases, and 6 multi-focal distant metastases at first recurrence diagnosis). The median time to recurrence was 8.5 months (95% CI, 6.6-10.5 months). Median survival after recurrence was 5.8 months (95% CI, 4.2-7.3 months). Stratification by recurrence location revealed significant differences in time to recurrence between loco-regional only recurrence (median, 13.6 months; 95% CI, 11.7-15.5 months) and simultaneous loco-regional with distant recurrence (median, 7.5 months; 95% CI, 4.6-10.4 months; p = 0.02, pairwise log-rank test). Significant predictors for recurrence were systemic inflammation index (SII) ≥ 500 (hazard ratio [HR], 4.5; 95% CI, 1.4-14.3), lymph node ratio ≥ 0.33 (HR, 2.8; 95% CI, 1.4-5.8), and adjuvant chemotherapy (HR, 0.4; 95% CI, 0.2-0.7). Conclusions: Timing to loco-regional only recurrence was significantly longer than simultaneous loco-regional with distant recurrence. Significant predictors for recurrence were SII, lymph node ration, and adjuvant chemotherapy.

• Journal of Korea Water Resources Association
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• v.53 no.5
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• pp.323-336
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• 2020

Owing to climate change, the annual precipitation in Korea has increased since the 20th century, and it is projected to continue increasing in the future. This trend of increasing precipitation will raise the possibility of floods; hence, it is necessary to establish national adaptation plans for floods, based on a reasonable flood risk assessment. Therefore, this study focuses on developing a framework that can assess the flood risk across the country, as well as computing the flood risk index (FRI). The framework, which is based on IPCC AR5, is established as a combination of three indicators: hazard, exposure, and capacity. A data-based approach was used, and the weights of each component were assigned to improve the validity of the FRI. A Spearman correlation analysis between the FRI and flood damage verified that the index was capable of assessing potential flood damage. When predicting scenarios for future assessment using the HadGEM3-RA based on RCP 4.5 and 8.5, the flood risk tends to be lower in the early and mid-21st century, and it becomes higher at the end of the 21st century as compared with the present.

• Ecology and Resilient Infrastructure
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• v.7 no.4
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• pp.327-335
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• 2020

The method of selecting an existing flood hazard area via a numerical model requires considerable time and effort. In this regard, this study proposes a method for selecting flood vulnerable areas through topographic analysis based on a surface runoff mechanism to reduce the time and effort required. Flood vulnerable areas based on runoff mechanisms refer to those areas that are advantageous in terms of the flow accumulation characteristics of rainfall-runoff water at the surface, and they generally include lowlands, mild slopes, and rivers. For the analysis, a digital topographic map of the target area (Seoul) was employed. In addition, in the topographic analysis, eight topographic factors were considered, namely, the elevation, slope, profile and plan curvature, topographic wetness index (TWI), stream power index, and the distances from rivers and manholes. Moreover, receiver operating characteristic analysis was conducted between the topographic factors and actual inundation trace data. The results revealed that four topographic factors, namely, elevation, slope, TWI, and distance from manholes, explained the flooded area well. Thus, when a flood vulnerable area is selected, the prioritization method for various factors as proposed in this study can simplify the topographical analytical factors that contribute to flooding.

• Journal of Environmental Science International
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• v.22 no.2
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• pp.163-171
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• 2013

The aggregate risk assessment on xylene and ethylbenzene was carried out according to the guidance established newly in 2010 with the purpose of providing information for risk management. In human exposure assessment, the results indicated that lower ages were exposed more and that, in the interior space at home, the highest level of human exposure occurred via inhalation. At outdoor spaces, exposures via inhalation and drinking were less than 1%. In human health risk characterization, xylene showed HI(Hazard Index) < 1 in all ages. When reasonable maximum exposure(RME) was applied, HI for young children was 0.64. The HI of ethylbenzene was also below 1(0.02~0.04) in all ages, indicating no potential risk. From this study, it is considered that xylene need to be continous monitoring with interest because this substance may be more sensitive on young age group. In additon, to reduce the uncertainty of the risk assessment, the korean exposure factors on young age group such as infant, children had to be established as soon as possible.

• Earthquakes and Structures
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• v.10 no.4
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• pp.849-865
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• 2016

Beside the invaluable advancements in constructing more secure buildings, the post-earthquake inspections have reported considerable damages. In other words, the modern buildings satisfactorily decrease fatalities but the monetary impacts still mostly remain an unsolved concern of the stakeholders, the insurance companies and society together. Therefore, the fundamental target of the researches shifted from current force-based seismic design regulations to the Performance-Based earthquake engineering (PBEE). At the moment, some probabilistic approaches, such as PEER framework have been developed to predict the performance of building at any desired hazard levels. These procedures are so time-consuming, to which many details are needed to be assigned. It causes their usage to be limited. On that account, developing more straightforward methods seems indispensable. The main objective of the present paper is to adapt an equivalent static method in different damage states. Consequently, constant damage spectrums corresponding to different limit states, soil types, ductility and fundamental periods are plotted and tri-linear formulas are proposed for further applications. Moreover, the sensitivity of outcomes to the employed hysteresis model, ductility, viscous damping and site soil type is investigated. Finally, a case study building with moment-resisting R.C. frame is evaluated based on the both of new and current methods to ensure applicability of the proposed method.

• International Journal of Highway Engineering
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• v.17 no.6
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• pp.117-126
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• 2015

PURPOSES : This study prioritizes potential technology for establishing a safe work zone environment on roadways. We consider almost all conceivable technologies that enable mitigation of unexpected accidents for both road workers and drivers. METHODS : This study suggests a methodology to set the priority of potential technology for establishing a safe work zone environment by using the analytical hierarchy process (AHP). For this purpose, the AHP structure was first developed. Thereafter, a web-based survey was conducted to collect experts' opinions. Based on the survey results, weights associated with the relevant criteria of the developed structure were estimated. With the consistency index (CI) and consistency ratio (CR), we verified the estimated weights. In addition, a sensitivity analysis was performed to confirm whether the estimated weights were reliable. We finally proposed the priority for potential technology for establishing a safe work zone environment on roadways. RESULTS : In the first level, safety technology has the highest priority, and real-time information delivery for work zone, hazard warning for drivers, and temporal automated operation for traffic facilities were selected in the second level of hierarchy. CONCLUSIONS : The results imply that establishing the priority will be useful to establish a future road map for improving the work environment for road workers and drivers by employing appropriate protection facilities and developing safety systems.

• 한국방재학회:학술대회논문집
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• 2011.02a
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• pp.83-83
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• 2011

도로의 동상방지층을 설치하기 위하여 동결관입깊이를 산정하며, 동결지수는 대기온도의 강도와 지속시간의 누가영향으로 표시된다. 대기온도는 일평균 대기온도를 사용하며 4개/일 평균(대기온도$_4$)을 사용하는 것이 일반적이지만, 현재 기상청에서 제공하고 있는 일평균 대기온도는 8개/일(대기온도$_8$)를 제공하고 있다. 이러한 일평균 대기온도의 산정하는 방법이 동결지수의 산정결과에 미치는 영향을 확인하기 위하여 한반도 남부지역(동결지수 $350^{\circ}C{\cdot}$일) 미만 6개지역을 저성토부, 절성경계부 및 절토부로 구분하여 15개소에 대하여 현장계측시스템을 구축하였다. 그리고 현장계측 시스템으로부터 얻어진 대기온도를 통하여 동결지수를 산정하여 비교하였다. 동결지수 비교결과 일반적으로 일평균 대기온도$_4$를 사용한 경우가 일평균 대기온도$_8$을 사용하는 경우보다 약 3% 전후 큰 것으로 나타나났으며, 6개 지역의 동결지수를 결정할 때 대기온도$_8$을 사용한 동결지수를 보정할 수 있는 보정식을 제안하였다.

• 한국방재학회:학술대회논문집
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• 2011.02a
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• pp.205-205
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• 2011

본 연구에서는 한반도의 유역별 대표 기상관측 지점을 선정하여 기후변화로 인하여 미래에 나타날 수 있는 가뭄의 경향성을 분석하였다. 분석을 위한 자료는 실제 강수량 자료(1974~1999년)와 A2시나리오를 따르는 5개의 GCMs(General Circulation Model) 자료를 통계적 상세화한 강수량 자료(1974~2099년)를 이용하여 산정한 지속기간 6개월의 SPI(Standardized Precipitation Index)를 사용하였다. 분석을 위한 대표 기상관측 지점으로는 춘천, 서울, 대전, 대구, 전주, 광주, 부산 지점을 선정하였으며 GCM으로는 호주(CSIRO : MK3), 미국(GFDL : CM2_1), 독일/한국(CONS : ECHO-G), 일본(MRI : CGCM2_3_2), 영국(UKMO : HADGEM1)의 GCM을 선정하였다. 가뭄의 통계적 특성을 분석하기 위하여 Mann-Kendall 검정을 통한 경향성 분석과 Wavelet Transform 분석을 통한 주기성 분석을 하였으며 Drought Spell을 이용하여 가뭄심도별 발생빈도를 보았다. 그 결과, 경향성 분석에서는 각 GCMs의 차이를 볼 수 있었으며 CSIRO : MK3.0, GFDL : CM2_1, MIUB : ECHO-G 모델에서는 전체적으로 가뭄이 완화되고 MRI : CGCM2_3_2, UKMO : HADGEM1 모델에서는 가뭄이 심화되는 것으로 나타났다. 주기성 분석에서는 춘천, 서울에서는 낮은 주기를 대전, 대구, 전주, 광주, 부산지점에서는 다소 긴 주기를 보여주었다. Drought-spell에 의한 분석에서는 전 관측지점에서 SPI의 이론적인 확률밀도 함수값과 유사하게 나타나고 있었으며 이를 통해, 미래에는 극심한 가뭄의 빈도가 증가하고 있는 것을 예측할 수 있었다.