• 한국환경보건학회지
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• 제48권5호
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• pp.272-281
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• 2022

Background: The constant consumption of chemical products owing to expanding industrialization has led to an increase in public interest in chemical substances. As the production and disposal processes for these chemical products cause environmental problems, regional information on the hazard level of chemical substances is required considering their effects on humans and in order to ensure environmental safety. Objectives: This study aimed to identify hazard contribution and spatiotemporal characteristics by region and chemical by calculating a hazard-based result score using pollutant release and transfer register (PRTR) data. Methods: This study calculated the chemical discharge and hazard-based result score from the Risk-Screening Environmental Indicators (RSEI) model, analyzed their spatiotemporal patterns, and identified hotspot areas where chemical discharges and high hazard-based scores were concentrated. The amount of chemical discharge and hazard-based risk scores for 250 cities and counties across South Korea were calculated using PRTR data from 2011 to 2018. Results: The chemical discharge (high densities in Incheon, Daegu, and Busan) and hazard-based result scores (high densities in Incheon, Chungcheongnam-do, and some areas of Gyeongsangnam-do Province) showed varying spatial patterns. The chemical discharge (A, B) and hazard-based result score (C, D) hotspots were identified. Additionally, identification of the hazard-based result scores revealed differences in the type of chemicals contributing to the discharge. Ethylbenzene accounted for ≥80% of the discharged chemicals in the discharge hotspots, while chromium accounted for >90% of the discharged chemicals in the hazard-based result score hotspots. Conclusions: The RSEI hazard-based result score is a quantitative indicator that considers the degree of impact on human health as a toxicity-weighted value. It can be used for the management of industries discharging chemical substances as well as local environmental health management.

• 한국산업보건학회지
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• 제21권2호
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• pp.103-109
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• 2011

Object: we investigated some factors which can affect workers' comprehension of chemical hazard information and their actions to protect themselves from the hazard. Method: Comprehension score of chemical hazard information and the rate of wearing personal protective equipment (PPE) was surveyed for the 109 workers from 15 factories who were exposed to N, N-dimethylformamide. Difference of the worker's comprehension score of hazard information was analyzed by education interval, work duration and the way of occupational safety and health management between self-managed or sub-contracted. Result: Mean comprehension score of N, N-dimethylformamide hazard, which was given as a short quiz composed of 10 "true" or "false" problems, was 65%. Mean percentage of wearing PPE was improved as the education program was done within a month but decreased after 6 months. Eighty seven % of workers got the chemical hazard information from the material safety data sheet placed at workplace. Conclusion: Education interval and comprehension score affected the rate of wearing PPE. The way of occupational safety and health management self-managed or sub-contracted did not affect the workers' comprehension score on hazard information nor the rate of wearing PPE.

• Communications for Statistical Applications and Methods
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• 제9권3호
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• pp.753-763
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• 2002

When there is one change-point in the hazard rate model, a change-point estimator with the partial score process is suggested and compared with the previously developed estimators. The limiting distribution of the partial score process we used is a function of the Brownian bridge. Simulation study gives the comparison of change-point estimators.

• 한국산업보건학회지
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• 제32권3호
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• pp.253-267
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• 2022

Objectives: This study was performed to check whether the CRS (Chemical Ranking and Scoring) system is appropriate as a method to determine substances as candidates for substances subject to permission and to apply this system to the selection of candidates for substances subject to permission. Methods: A risk score was obtained by multiplying the hazard score and the exposure score and then ranking them. The hazard sub-indicators are carcinogenicity, germ cell mutagenicity, reproductive toxicity, specific target organ toxicity-repeated exposure, respiratory sensitization and endocrine disrupting chemicals. Exposure sub-indicators are persistence, bioaccumulation and emission volume. Sensitivity analysis was performed for missing values. Correlation analysis and multivariable linear regression analysis were performed among hazard, exposure and risk in order to confirm that CRS was an appropriate method. Results: As a result of the sensitivity analysis on missing values, it was confirmed that the effect on the risk ranking was not sensitive. Correlation and regression analysis confirmed that exposure had a greater effect on risk than hazard. Conclusions: The CRS system, which derives a risk score using a hazard and exposure score, is judged to be appropriate as a method for the selection of preliminary of candidates for substances subject to permission. Benzene, cadmium, nickel, and cobalt were selected as priority candidates for substances subject to permission.

• 한국산림과학회지
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• 제97권3호
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• pp.332-339
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• 2008

경상북도 23개 시․군 산사태 발생지 172개소를 대상지로 선정하여 산사태 발생 특성을 다양한 요인별로 조사 분석하여 산사태 발생 위험 예측을 위한 판정기준표를 작성하였다. 산사태 위험 판정기준표는 수량화 I류를 이용하여 분석하였으며, 산사태 발생량에 영향을 많이 주는 요인은 경사위치, 경사길이, 모암, 방위, 임분경급, 종단명형, 경사도의 순으로 나타났다. 산사태 발생 위험 예측을 위한 산사태 붕괴 위험도 판정기준표를 작성한 결과, 107점 미만 : 안정(IV등급), 107~176점 : 위험도 소(III등급), 177~246점 : 위험도 중(II등급), 247점 이상 : 위험도 대(I등급)로 붕괴 위험도가 구분되었다.

• 환경영향평가
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• 제6권2호
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• pp.113-121
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• 1997

LHR(Landfill Hazard Ranking Model) was developed for assessing the relative hazard of landfills by using the method of value-structured approach. LHR consists of combining a multiattribute decision-making method with a qualitative risk assessment approach. A pairwise comparision method was applied to determine weights of landfill factors related. To prove the validity of weights allocation of landfill hazard evaluation factors, sensitivity analysis was applied. Firstly, the impact on landfill hazard score according to variations of weights of landfill hazard factors was analyzed. Secondly, the impact on landfill hazard score according to conditions change of landfill hazard factors was analyzed. As a result of sensitivity analysis, LHR composite scores are largely influenced by some factors following sequential order such as waste volume, proximity to sensitive environments, containment facilities, distance from drinking water supplies, and waste toxicity. The relative order of landfill hazard evaluated by LHR is not influenced by the weights change of individual factors. Therefore, LHR seems to be a credible model to determine priorities of landfill remediation based on the vulnerability of water resources.

• Journal of Hospice and Palliative Care
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• 제20권4호
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• pp.235-241
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• 2017

목적: Palliative Performance Scale (PPS)는 진행성 암환자에서 널리 사용되는 예후도구이다. PPS 측정이 생존에 대한 예측을 의미하지만, 연속적인 PPS 측정에 대한 유용성은 추가적인 연구가 필요하다. 본 연구에서는 완화 병동에 입원한 진행성 암환자를 대상으로 PPS score의 변화와 생존간의 연관성에 대해 진행한 연구이다. 방법: 2010년 1월부터 2012년 12월까지 서울성모병원 완화의학과에 입원한 환자 606에 대한 의무기록을 통하여 입원 당일의 PPS score와 입원 3일째의 PPS score 그리고, 두 score의 차이를 측정하여 점수의 변화와 생존간의 관련성을 분석하였다. 결과: PPS score의 변화와 생존과는 통계적으로 유의한 관련이 있었다. PPS score의 변화가 30% 이하인 군과 비교하였을 때, 30% 초과된 군에서 hazard ratio가 2.66(95% CI 2.19~3.22)로 확인되었다. 입원 3일째 PPS score가 30% 이하인 경우 독립적으로 생존에 대한 예측이 가능하였으며, PPS score 30% 초과된 군과 비교했을 때 hazard ratio는 1.67 (95% CI 1.38~2.02)로 확인되었다. 입원 당시의 PPS score는 생존과 독립적인 관련성은 없었다. 결론: 후향적으로 의무기록 분석을 통해 이루어진 본 연구에서 30% 이상의 PPS score 변화는 입원중인 말기 암환자의 생존과의 관련이 확인되었다. 입원 당시의 PPS score는 생존을 예측하지 못했다. PPS score의 변화는 말기암환자에서 단일 PPS score 측정보다 더 민감한 지표일 수 있다. 차후 더 많은 환자들에서 이에 대한 다기관, 전향적 연구가 필요하다.

• Communications for Statistical Applications and Methods
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• 제27권6호
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• pp.675-688
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• 2020

In survival analysis of observational data, the inverse probability weighting method and the Cox proportional hazards model are widely used when estimating the causal effects of multiple-valued treatment. In this paper, the two kinds of weights have been examined in the inverse probability weighting method. We explain the reason why the stabilized weight is more appropriate when an inverse probability weighting method using the generalized propensity score is applied. We also emphasize that a marginal hazard ratio and the conditional hazard ratio should be distinguished when defining the hazard ratio as a treatment effect under the Cox proportional hazards model. A simulation study based on real data is conducted to provide concrete numerical evidence.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2015년도 학술발표회
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• pp.236-236
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• 2015

Flood is one of the major natural disasters affecting millions of people. Thailand also, frequently faces with this type of disaster. Especially, 2011 mega flood in Central Thailand, inundated highway severely attributed to the failure of national economic and risk to life. Lesson learned from such an extreme event caused flood monitoring and warning becomes one of the sound mitigations. The highway flood hazard mapping accomplished in this research is one of the strategies. This is due to highway flood is the potential risk to life and limb, and potential damage to property. Monitoring and warning therefore help reducing live and property losses. In this study, degree of highway flood hazard was assessed by weighting factors for each cause of the highway flood using Multi Criteria Analysis (MCA) based Analytic Hierarchy Process (AHP). These weighting factors are the essential information to classify the degree of highway flood hazard to enable pinpoint on flood monitoring and flood warning in hazard areas. The highway flood causes were then investigated. It was found that three major factors influence to the highway flood are namely the highway characteristics, the hydrological characteristics and the land topography characteristics. The weight of importance for each cause of the highway flood in the whole country was assessed by weighting 3 major factors influence to the highway flood. According to the result of MCA analysis, the highway, the hydrological and the land topography characteristics were respectively weighted as 35, 35 and 30 percent influence to the cause of highway flood. These weighting factors were further utilized to classify the degree of highway flood hazard. The Weight Linear Combination (WLC) method was used to compute the total score of all highways according to each factor. This score was later used to categorize highway flood as high, moderate and low degree of hazard levels. Highway flood hazard map accomplished in this research study is applicable to serve as the handy tool for highway flood warning. However, to complete the whole warning process, flood water level monitoring system for example the camera gauge should be installed in the hazard highway. This is expected to serve as a simple flood monitor as part of the warning system during such extreme or critical event.

• 한국산업보건학회지
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• 제32권3호
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• pp.209-220
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• 2022

Objectives: This study was performed to suggest how to re-establish criterion for toxic substances under the Chemical Control Act (CCA) in South Korea by comparing the GHS (Globally Harmonized System of Classification and Labeling of Chemicals) score and toxic properties. Methods: Toxic substances were classified into seven groups (Acute toxicity (1A), Chronic toxicity (2C), Environmental hazards (3E), Acute toxicity & chronic toxicity (4AC), Chronic toxicity & environmental hazards (5CE), Acute toxicity & environmental hazards (6AE), and Acute toxicity & chronic toxicity & environmental hazards (7ACE)) according to their toxic properties. The GHS score was calculated to sum up five toxicity indicators (health acute toxicity, health repeated toxicity, carcinogenicity, health other chronic toxicity and environmental hazards). Results: The GHS score of 7ACE was higher by 7 times that of 1A. 1A is the only group which has lower than the total GHS score. The highest score was 47, for sodium chromate (CAS no. 7775-11-3), which belongs to group 7ACE. This is classified as acute toxicity, carcinogenicity, germ cell mutagenicity, reproductive toxicity, and acute and chronic environmental hazard. On the other hand, the lowest score was 2.75, which was assigned to 177 chemicals belonging to group 1A. When the health acute toxicity indicator was omitted from the toxic criterion, toxic substances could be divided into the sub-groups 'human chronic hazards group' (HCG) and 'environmental hazards group' (EG) according to their GHS score and properties. Conclusions: The proposed criterion for toxic substances is to establish sub-groups defined as HCG and EG for separate control and that the 1A group be moved to substances requiring preparation for accidents under the CCA.