• Korean Journal of Radiology
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• 제24권7호
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• pp.626-639
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• 2023

Objective: To investigate the association of clinical, pathologic, and magnetic resonance imaging (MRI) variables with progressive disease (PD) during neoadjuvant chemotherapy (NAC) and distant metastasis-free survival (DMFS) in patients with triple-negative breast cancer (TNBC). Materials and Methods: This single-center retrospective study included 252 women with TNBC who underwent NAC between 2010 and 2019. Clinical, pathologic, and treatment data were collected. Two radiologists analyzed the pre-NAC MRI. After random allocation to the development and validation sets in a 2:1 ratio, we developed models to predict PD and DMFS using logistic regression and Cox proportional hazard regression, respectively, and validated them. Results: Among the 252 patients (age, 48.3 ± 10.7 years; 168 in the development set; 84 in the validation set), PD was occurred in 17 patients and 9 patients in the development and validation sets, respectively. In the clinical-pathologic-MRI model, the metaplastic histology (odds ratio [OR], 8.0; P = 0.032), Ki-67 index (OR, 1.02; P = 0.044), and subcutaneous edema (OR, 30.6; P = 0.004) were independently associated with PD in the development set. The clinical-pathologic-MRI model showed a higher area under the receiver-operating characteristic curve (AUC) than the clinical-pathologic model (AUC: 0.69 vs. 0.54; P = 0.017) for predicting PD in the validation set. Distant metastases occurred in 49 patients and 18 patients in the development and validation sets, respectively. Residual disease in both the breast and lymph nodes (hazard ratio [HR], 6.0; P = 0.005) and the presence of lymphovascular invasion (HR, 3.3; P < 0.001) were independently associated with DMFS. The model consisting of these pathologic variables showed a Harrell's C-index of 0.86 in the validation set. Conclusion: The clinical-pathologic-MRI model, which considered subcutaneous edema observed using MRI, performed better than the clinical-pathologic model for predicting PD. However, MRI did not independently contribute to the prediction of DMFS.

• 한국방재학회 논문집
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• 제6권4호통권23호
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• pp.37-47
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• 2006

도시화로 인한 유출량의 증가 및 도달시간의 단축은 도시재해의 한 원인이 되고 있다. 이를 막기 위하여 도시 배수유역내에 저류지를 설치하여 하수관거의 통수능 이하로 방류량을 조절하는 방안을 고려할 수 있다. 기초계획 단계에서의 저류지 설계를 위해서는 복잡한 연관성을 지니고 있는 제반 변수를 고려하지 않고 대표적인 관련 주요변수를 택하여 저류용량을 결정하는 여러 가지 저류지 계획모형이 이용되고 있다, 기왕의 저류지 계획모형에서는 주로 도시화 특성인자인 첨두유량비$(\alpha)$와 도달시간비$(\gamma)$를 활용하고 있다. 본 연구에서는 재해영향평가서 22개소의 저류지를 분석대상으로 하여 도시화에 따른 도시배수유역 특성인자와 저류지 특성인자간의 분석을 통해 저류지의 계획단계에서 활용할 수 있도록 편의성을 도모하고자 한다. 첨두유량비 $\alpha$가 도달시간비 $\gamma$보다 저류 용량에 미치는 영향이 더욱 민감함을 알 수 있었으며, 개발전 후의 유출계수비 $\beta$가 설계강우강도의 지역계수 n값 보다 $\alpha$에 미치는 영향이 작음을 알 수 있었다. 사다리꼴 설계수문곡선을 사용하는 경우에는 강우지속기간이 저류비에 미치는 영향이 큰 것을 알 수 있었다.

• 한국산업보건학회지
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• 제22권3호
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• pp.175-183
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• 2012

Objectives: This study developed a harmonized method for risk assessment based on the Hazard & Risk Evaluation of Chemicals (HREC) according to the Industrial Safety and Health Act (ISHA). Methods: Three preliminary studies, performed during 2010 and 2011 by the Occupational Safety and Health Research Institute and three academic research groups, were compared. The differences in risk assessment, especially in the dose-response assessment method, were analyzed. A new harmonized method for dose-response assessment was suggested and its applicability for the HREC was examined. Results: Considering the various steps of each dose-response assessment, the equivalent steps in quantitative correction, uncertainty factor 2 (UF2) for intra-species uncertainty, and UF3 for the experimental period in the uncertainty correction were relatively high. Using our new method, the total correction values (quantitative correction plus uncertainty correction) ranged from 72~15,789 to 30~60, and the ratio of the threshold limit value (TLV) to the reference concentration decreased from 12.8~1900 to 5.4~11.8. Furthermore, when we performed risk characterization by our new method, hazard quotient (HQ) values for chloroethylene, epichlorohydrin, and barium sulfate became 3.0, 14.1, and 1.13 respectively, whereas three previous studies reported HQ values of 7.1, 4580, and 87.3 considering reasonable maximum exposure (RME) conditions. HQs of the three chemicals were calculated to be 0.6, 2.4, and 0.1 respectively, when compared to their TLVs. Conclusions: Our new method could be applicable for the HREC because the total correction values and the ratio of TLVs were within reasonable ranges. It is also recommended that additional risk management measures be applied for epichlorohydrin, for which the HQ values were greater than 1 when compared with both reference values and the TLV. Our proposed method could be used to harmonize dose-response assessment methods for the implementation of risk assessment based on the HREC according to ISHA.

• 산경연구논집
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• 제9권7호
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• pp.43-52
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• 2018

Purpose - The main purpose of this paper is to examine the effect of children's age on maternal labor supply in Korea using survival analysis. Specifically, we focus on the career re-interruption of women having children under age 12, which has rarely been studied in the existing literature. Research design, data, and methodology - We use micro data from the Korea Labor and Income Panel Study (KLIPS) surveyed from 1998 to 2016. Instead of using a pre-school child dummy or the number of young children as an explanatory variable, 9 children's age dummies are included to capture the effect of nurturing 0 to 9 years old children. This study estimates the hazard of a woman's exiting the labor market after her first experience of the career interruption, rather than the hazard of the first career interruption itself. A Cox proportional hazard model is applied to numerically capture the impact of children's age on behavioral changes in maternal labor supply. The sample used in this analysis is women between 15 and 54 years old. Most of all, we restrict the sample to women who had at least a child between 0 and 12 years old at the time of quitting their jobs. Results - The Cox proportional hazard model estimates show a strong negative effect of a 0-year-old child on maternal labor supply. Mothers with newborns have a high hazard ratio of labor force exit after the re-entry. The hazard of women with infants is three times higher than those with children aged 10 to 18. Additionally, the results show that not only newborns, but also children in the age of school-entry have a negative impact on their mother's labor supply. Conclusions - The findings reveal that children's ages need to be properly expanded and included when analyzing the effect of children and their ages on married women's labor supply, especially on women's career re-interruption. A large negative effect of 7-year-old children on maternal labor supply found here indicates that supporting mothers with school age children as well as pre-school children is necessary to prevent mothers from leaving the labor market.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2007년도 정기총회 및 학술발표대회
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• pp.632-635
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• 2007

Detention pond has an important role in peak flow reduction to mitigate flood damage. Design of detention pond is accomplished through the preliminary stage, planning stage, and design stage in general. New development projects produce increased peak flow and flow amounts. In this case it is necessary to design the detention pond easily and simply. The simple procedure of detention pond design is proposed in this study. The relevant variables are peak flow ratio ($\alpha$) for the before and after development, and storage ratio which is ratio of storage volume to flow amounts. Simplified method for the detention pond design with runoff reduction is easily used for practical purposes.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 춘계학술대회 논문집
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• pp.71-74
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• 2008

In order to resolve the problems which appear after the clean large ingot production process, the impurities which are involved in the steel smelting process should be removed by developing cleaner materials. Through the rationalization of cogging process that is the first forging process of large ingot the quality is to be improved. For the sake of the optimization of an open die forging process and the improvement of the subject matter frequency ratio, a hazard precise die forging process must be developed and a Near Net Shape Forming accomplished. As a result, energy can be reduced by minimizing an after control process. In order to produce large axes and other forming parts, processing techniques are to be developed. In this context, this paper is a study about a reduction ratio, dies width ratio and rotary angles, the amount of overlap, and intends to analysis cogging processes, utilizing Deform-3D cogging module

• Journal of the Korean Data and Information Science Society
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• 제22권2호
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• pp.217-225
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• 2011

정신장애 질병과 관련된 위험인자를 찾는 것은 매우 중요한 일이다. 또한 질병과 관련된 위험인자들의 연관성을 나타내는 위험비는 의학에서 주된 관심이 된다. 따라서 우리는 정신장애 질병과 위험인자 간의 연관성을 살펴보기 위해 오즈비를 활용한다. 본 논문에서는 베이지안 네트워크를 정신장애질병인 섬망자료에 적용하여 선별된 주요 위험인자들의 오즈비를 찾았다. 특히 선별된 주요 위험인자들이 단일로 존재할 때의 오즈비와 위험인자가 복합적으로 존재할 때의 오즈비를 통하여 섬망에 가장 위험한 영향을 미치는 위험인자를 규명하였다.

• Asian Pacific Journal of Cancer Prevention
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• 제15권21호
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• pp.9453-9458
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• 2014

Background: Breast cancer is the second leading cause of cancer death for women in the United States. Differences in survival of breast cancer have been noted among racial and ethnic groups, but the reasons for these disparities remain unclear. This study presents the characteristics and the survival curve of two racial and ethnic groups and evaluates the effects of race on survival times by measuring the lifetime data-based half-normal model. Materials and Methods: The distributions among racial and ethnic groups are compared using female breast cancer patients from nine states in the country all taken from the National Cancer Institute's Surveillance, Epidemiology, and End Results cancer registry. The main end points observed are: age at diagnosis, survival time in months, and marital status. The right skewed half-normal statistical probability model is used to show the differences in the survival times between black Hispanic (BH) and black non-Hispanic (BNH) female breast cancer patients. The Kaplan-Meier and Cox proportional hazard ratio are used to estimate and compare the relative risk of death in two minority groups, BH and BNH. Results: A probability random sample method was used to select representative samples from BNH and BH female breast cancer patients, who were diagnosed during the years of 1973-2009 in the United States. The sample contained 1,000 BNH and 298 BH female breast cancer patients. The median age at diagnosis was 57.75 years among BNH and 54.11 years among BH. The results of the half-normal model showed that the survival times formed positive skewed models with higher variability in BNH compared with BH. The Kaplan-Meir estimate was used to plot the survival curves for cancer patients; this test was positively skewed. The Kaplan-Meier and Cox proportional hazard ratio for survival analysis showed that BNH had a significantly longer survival time as compared to BH which is consistent with the results of the half-normal model. Conclusions: The findings with the proposed model strategy will assist in the healthcare field to measure future outcomes for BH and BNH, given their past history and conditions. These findings may provide an enhanced and improved outlook for the diagnosis and treatment of breast cancer patients in the United States.

• Asian Pacific Journal of Cancer Prevention
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• 제14권8호
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• pp.4727-4731
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• 2013

Background: There have been no large-scale population-based studies to estimate the subsequent risk of primary liver cancer (PLC) among patients with pyogenic liver abscess (PLA). This study aimed to provide relevant data. Materials and Methods: The Taiwan Longitudinal Health Insurance Database for the years 2000 and 2005 was used. The PLA group were adult inpatients who were newly diagnosed with PLA from 2000 to 2008. The control group was randomly selected and matched with the PLA group in terms of age, sex, and date in which medical treatment was sought other than for PLA. Results: There were 1,987 patients each in the PLA and control groups. In total, 56 had PLC, 48 (2.4%, 601.5 per 100,000 person-years) from the PLA group, and 8 from the control group. After adjusting for potential covariates, the hazard ratio of PLC for the PLA group was 3.4 times that of the control group (95% confidence interval = 1.6-7.3, p <0.001). The PLC risk for the PLA group was significantly higher within the first year after PLA diagnosis (hazard ratio: 35.4) as compared with the control group and became insignificant (hazard ratio: 2.0, 95% confidence interval = 0.8-4.9) more than one year after PLA diagnosis. Conclusions: Patients with PLA have a higher rate of PLC than matched controls, especially within the first year after the diagnosis of PLA, suggesting PLA is a warning sign for PLC.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2008년도 정기총회 및 학술발표대회
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• pp.153-156
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• 2008

Comparative analysis of forest fire danger rating on the forest characteristics of thinning area and non-thinning area on forest fire burnt area was studied in this work. To investigate the effect of thinning slash in forest fire, Gangneung-si Wangsan-myeon, Ulgin-gun Wonnam-Myeon, Samchok-si Gagok-Myeon, in which forest fire broke out, were selected. As a result that investigated forest fire danger ratio between thinning slash and non-thinning slash, leeward scorching ratio(36%), crown damage ratio(29%), mortality of branch at the former are higher than those at the latter, leeward scorching ratio of tree, where thinning slash is around, is 10%-20% higher than that of independent tree. So I estimate that thinning slash has a some effect on the intensity of forest fire. And the result to investigate damage of forest fire according to tree species shows that leeward scorching ratio of conifer is 5% higher than that of non-conifer, and mortality of branch of the former is 19% higher than that of the latter. It is considered that forest fire may affect directly to a tree trunk if it diffuse to piled thinning tree because there was no space between thinning trees and trees. Furthermore, it was found that re-ignition had a chance to occur due to lots of piled thinning trees.