• 한국산업보건학회지
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• 제25권4호
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• pp.506-515
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• 2015

Objectives: This study was conducted to evaluate the status of hazard communication regarding dental materials among dental hygienists in the Daegu Metropolitan City and the North Gyeongsang-do Province area. Materials: A total of 310 dental hygienists were surveyed using self-administered questionnaires to investigate the status of hazard communication on dental materials and information needs. We collected instructions for use and material safety data sheets(MSDSs) for 67 dental materials frequently used at dental hospitals located in the Daegu Metropolitan City and the North Gyeongsang-do Province area. Results: The questionnaire surveys showed that only 11% of the 310 dental hygienists had knowledge of MSDS and 46.8% of respondents never read instructions for use before using materials. Just 7.4% of dental hygienists have undergone training on hazard information for dental materials. In particular, dental hygienists working at dental clinics had significantly lower response rates on knowledge of MSDS(p<0.001), reading of instructions for use(p=0.042) and training on the hazard information of dental materials(p=0.004) than those in dental hospitals or general hospitals. The essential information most desired by dental hygienists was hazard identification(82.3%) followed by first-aid measures(53.9%), handling and storage(51%), disposal considerations (49%) and toxicological information(47.1%). All dental materials were on foreign products which came from Japan(59.7%), the USA(26.9%) and Liechtenstein(13.7%). In terms of usage, 56.7% of dental materials were prosthetic, followed by conservation(31.3%), orthodontics(9%), and prevention(3%). We found that dental hygienists had accessed MSDSs for only five dental products among the 67 dental materials. The instructions for the use of the 67 dental materials provided hazard identification(64.2%), first-aid measures(83.6%), handling and storage(97%), disposal considerations(20.9%) and toxicological information(26.9%). Conclusions: Based on the results of this study, the hazard communication system for dental hygienists working at dental clinics should be improved.

• Journal of the Korean Wood Science and Technology
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• 제39권6호
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• pp.531-537
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• 2011

본 연구는 지상부 사용조건에서 야외에 노출된 목재의 부후위험을 평가하기 위하여 수행되었다. 국내 72개 장소에서 10년 동안 축적된 기후자료를 활용하여 Scheffer 지수가 계산되었으며, 이에 근거하여 목재부후위험지도가 작성되었다. 제주, 서귀포, 광주, 전주 지역의 Scheffer 지수가 65 이상으로 부후위험이 높은 지역에 속하는 것으로 나타났으며, 이 지역을 제외한 나머지 지역은 Scheffer 지수가 35에서 65 사이의 값을 보여 부후위험이 중간 정도인 것으로 판명되었다. 그러나 기후조건에 따른 Scheffer 지수의 편차가 크기 때문에 부후위험이 중간정도로 판단된 지역이 기후변화에 따라 부후위험이 높은 지역으로 변할 수 있는 가능성이 높은 것으로 보인다. 특히 최근의 국내 기후가 아열대성으로 변화하는 경향을 고려할 때 국내 부후위험은 점차적으로 증가할 것으로 판단된다.

• 한국지반환경공학회 논문집
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• 제10권7호
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• pp.111-115
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• 2009

국내에서는 지반의 설계응답스펙럼을 확률론적으로 생성한 지진재해도와 결정론적으로 유도된 지진계수를적용하여 생성한다. 지진재해도와 지진계수는 호환되지 않지만, 현 설계기준은 이런 근본적인 비호환성을 무시하고 있다. 지진재해도와 지진계수를 동일한 확률론적 기반에서 생성한다면 이와 같은 문제를 극복할 수 있지만, 기존의 방법으로는 지진계수를 확률론적으로 생성할 수 없다. 본 논문에서는 동반논문에서 신(新) PSHA의 결과물로써 생성된 지진기록을 입력지진파로 활용하여 1차원 등가선형 지반응답 해석을 수행하였으며 이의 결과를 기반으로 등재해스펙트럼을 생성하였다. 등재해스펙트럼의 또 한가지 장점은 지반물성치의 불확실성과 임의성이 과학적으로 고려되었다는 점이다. 등재해스펙트럼은 나아가 확률론적인 지진계수를 도출하는데 활용되었다. 확률론적인 지진계수를 내진설계기준에서 제시된 지진계수를 비교한 결과, 확률론적으로 계산된 지진계수는 결정론적으로 계산된 결과와 상당한 차이가 있는 것으로 나타났다.

• 한국물환경학회지
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• 제23권1호
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• pp.87-96
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• 2007

In this paper a methodology of identifying individual pipes according to the internal and external characteristics of pipe is developed, and the methodology is applied to a case study water distribution pipe break database. Using the newly defined individual pipes the hazard rates of the cast iron 6 inch pipes are modeled by implementing the proportional hazards modeling approach for consecutive pipe failures. The covariates to be considered in the modeling procedures are selected by considering the general availability of the data and the practical applicability of the modeling results. The individual cast iron 6 inch pipes are categorized into seven ordered survival time groups according to the total number of breaks recorded in a pipe to construct distinct proportional hazard model (PHM) for each survival time group (STG). The modeling results show that all of the PHMs have the hazard rate forms of the Weibull distribution. In addition, the estimated baseline survivor functions show that the survival probabilities of the STGs generally decrease as the number of break increases. It is found that STG I has an increasing hazard rate whereas the other STGs have decreasing hazard rates. Regarding the first failure the hazard ratio of spun-rigid and spun-flex cast iron pipes to pit cast iron pipes is estimated as 1.8 and 6.3, respectively. For the second or more failures the relative effects of pipe material/joint type on failure were not conclusive. The degree of land development affected pipe failure for STGs I, II, and V, and the average hazard ratio was estimated as 1.8. The effects of length on failure decreased as more breaks occur and the population in a GRID affected the hazard rate of the first pipe failure.

• 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.

• 인터넷정보학회논문지
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• 제20권3호
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• pp.1-11
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• 2019

자동차, 원자력, 철도, 항공 등의 분야에서 발생하는 소프트웨어의 고장이나 사고는 바로 큰 재산 피해나 인명 피해로 연결될 수 있다. 이에 체계적이고도 효과적인 안전품질 관리의 필요성이 커지고 있으며, 최근 관련 산업 분야에서는 IEC 61508을 기반으로 안전 국제 표준이 제정되어 산업에 적용되고 있다. 국제 표준에서 명시하고 있는 안전 생명주기에 따르면 소프트웨어 안전성 품질을 확보하기 위해서는 개발 초기 단계에서 위험원 및 위험 분석(Hazard and risk analysis)을 통한 안전 요구사항을 개발하도록 권고하고 있다. 본 논문에서는 소프트웨어의 안전성 요구사항의 식별 및 정의를 위해 SysML을 활용한 STPA 기반의 위험원 분석 프로세스를 제안한다. 세부적으로는 SysML의 BDD과 IBD 다이어그램을 활용하여 기존 STPA 분석에서 활용되고 있는 제어구조도를 보다 명확하게 정의할 수 있도록 개선하였고, SD 다이어그램을 활용하여 안전 제약사항(요구사항)을 상세화할 수 있도록 하였다. 제안 방법의 적용 결과, STPA에서 누락되었던 위험원을 추가적으로 식별할 수 있었고, 위험원의 발생 시나리오도 상세하게 구체화할 수 있었다.

• Earthquakes and Structures
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• 제24권4호
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• pp.303-316
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• 2023

Rapid post-earthquake damage estimation of subway stations is particularly necessary to improve short-term crisis management and safety measures of urban subway systems after a destructive earthquake. The conventional Performance-Based Earthquake Engineering (PBEE) framework with constant earthquake occurrence rate is invalid to estimate the aftershock risk because of the time-varying rate of aftershocks and the uncertainty of mainshock-damaged state before the occurrence of aftershocks. This study presents a time-varying probabilistic seismic risk assessment framework for underground structures considering mainshock and aftershock hazards. A discrete non-omogeneous Markov process is adopted to quantify the time-varying nature of aftershock hazard and the uncertainties of structural damage states following mainshock. The time-varying seismic risk of a typical rectangular frame subway station is assessed under mainshock-only (MS) hazard and mainshock-aftershock (MSAS) hazard. The results show that the probabilities of exceeding same limit states over the service life under MSAS hazard are larger than the values under MS hazard. For the same probability of exceedance, the higher response demands are found when aftershocks are considered. As the severity of damage state for the station structure increases, the difference of the probability of exceedance increases when aftershocks are considered. PSDR=1.0% is used as the collapse prevention performance criteria for the subway station is reasonable for both the MS hazard and MSAS hazard. However, if the effect of aftershock hazard is neglected, it can significantly underestimate the response demands and the uncertainties of potential damage states for the subway station over the service life.

• 대한원격탐사학회지
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• 제34권1호
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• pp.75-87
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• 2018

The Baekdu volcano (2,750 m a.s.l.) is located on the border between Yanggando Province in North Korea and Jilin Province in China. Its eruption in 946 A.D. was among the largest and most violent eruptions in the past 5,000 years, with a volcanic explosivity index (VEI) of 7. In this study, we processed and analyzed lahar-inundation hazard zone data, applying a geographic information system program with menu-driven software (LAHARZ)to a shuttle radar topography mission 30 m digital elevation model. LAHARZ can simulate inundation hazard zones created by large lahar flows that originate on volcano flanks using simple input parameters. The LAHARZ is useful both for mapping hazard zones and estimating the extent of damage due to active volcanic eruption. These results can be used to establish evacuation plans for nearby residents without field survey data. We applied two different simulation methods in LAHARZ to examine six water systems near Baekdu volcano, selecting weighting factors by varying the ratio of height and distance. There was a slight difference between uniform and non-uniform ratio changes in the lahar-inundation hazard zone maps, particularly as slopes changed on the east and west sides of the Baekdu volcano. This result can be used to improve monitoring of volcanic eruption hazard zones and prevent disasters due to large lahar flows.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 1997년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall 1997
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• pp.11-26
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• 1997

It has knows that the seismicity of the Korean Peninsula is relatively inactive than those of adjacent northern China and southwestern Japan. Recently the review of long term historical records and recent seismicity. In addition, it is considered that the modern society is more vulnerable to seismic hazard because of high urbanization and industrialization. From this viewpoint, the improvement and modification of the present regulation for aseismic design is strongly proposed. The purpose of the present study is to prepare seismic hazard maps for Korea to be used in improving the present regulation. The present study was performed as a cooperative project of eight Korean seismologists. Each seismologist calculated independently seismic hazard value at the given grid points based on his own judgement about methodology and seismicity. Then the values are unified with equal weight to produce a seismic hazard map. Seven seismic hazard maps for peak acceleration with 10 percentile probability of exceedance in 5, 10, 20, 50, 100, 250, 500 years are presented. This probability of exceedancd in such years corresponds to return period of 48, 95, 190, 475, 950, 2373, 4747 years, respectively. It is recommended to use a hazard map to be selected on the basis of the importance and the design level of structures.

• 대한안전경영과학회지
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• 제13권4호
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• pp.9-16
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• 2011

Modern systems become more complex and the demand for systems safety goes up sharply. Thus, the proper handling of the safety requirements in the systems design is getting greatly increased attention these days. Hazard analysis has been one of the active areas of research in connection with systems safety. In this paper, we study a subject on how the hazard analysis results can be incorporated in the systems design. To this end we set up a goal on how to systematically generate safety requirements that should reflect hazard analysis results and be implemented in the systems design and development. To do so, we first review the process for systems design and suggest the associated Model. Then the process and results of hazard analysis are analyzed and Modeled particularly with emphasis on the safety data. The resulting data Model incorporating both the hazard analysis and system life cycle is used in the generation of safety requirements. Based on the developed data Model, the generation of the requirements, the construction of requirements DB, and the change management later on is demonstrated through the use of a computer-aided software tool.