• 대한조선학회논문집
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• 제49권3호
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• pp.239-246
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• 2012

It is the well-known fact that most part of goods transported are moved on the unfavorable ocean and even a small amount of accident on sea is extremely dangerous for human lives, financial losses, and social responsibility. Among the several causes of accidents, those by fire have occurred frequently and their damage has been highly serious. The aim of this paper is to assess the risk of fires due to oil leakage in the machinery space. To define the possible fire scenario, our team has performed the search of casualty database and reviewed the previous and various studies in the field. As a result, it is noted that the quantitative risk of the fire scenario have been evaluated on the ground of the FSA risk model. The expected frequency of a fire amounts to incidents during the life of a ship, and the expected financial damage amounts to 5,654 USD per a ship. By adopting Safety Instrumented System (SIS) introduced in IEC 61508 and IEC 61511, SIS model is designed to prevent oil leakage fire as a risk reduction method. It is concluded that System Integrity Level (SIL) 1 seems to be appropriate level of SIS.

• 대한조선학회논문집
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• 제49권6호
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• pp.447-460
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• 2012

In this study, the shutdown system of the fuel gas supply system is designed based on the Safety Integrity Level of IEC 61508 and IEC 61511. First of all, the individual risk($10^{-4}$/year) and the risk matrix which are the risk acceptance criteria are set up for the qualitative risk assessment such as the HAZOP study. The natural gas leakage at the gas supply pipe is identified as the highest risk among the hazards identified through the HAZOP study and as a safety instrumented function the shutdown function for leakage was defined. SIL 2 and PFD($2.5{\cdot}10^{-3}$) for the shutdown function are determined by the layer of protection analysis(LOPA). The shutdown system(SIS) carrying out the shutdown function(SIF) is verified and designed according to qualitative and quantitative requirements of IEC 61508 and IEC 61511. As a result of SIL verification and SIS conceptual design, the shutdown system is composed of two gas detectors voted 1oo2, one programmable logic solver, and two shutdown valve voted 1oo2.

• Korean Journal of Acupuncture
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• 제27권2호
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• pp.107-120
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• 2010

Objectives : The aim of this study is to measure pulse waveforms by applying 5-level graded pressure, and selecting optimum pulse waveforms. Also to proposing the possibility of using AW(Area of the 1/3 upper height of h1) rate in respect to AT(Total Area) for risk assessment of hypertension or arteriosclerosis is another aim of the study. Methods : Pulse waveforms of normotensive were measured by 5-level graded pressure. The pulse waveforms well reflecting properties of blood vessel(having the largest h1) were selected for optimum pulse waveforms. Various parameters(h-parameter, t-parameter, and others) of optimum pulse waveforms were analyzed. AIx(Augmentation index) was calculated by height-parameters to assess arterial stiffness. The area rate of the 1/3 upper height for h1 in respect to total area was analyzed according to aging. Results : According to aging 1. in height-parameter, h2 and h3 were increased but h5 was decreased. 2. In time-parameter, t2, t3, and t5 were getting short. 3. Area of systolic period was increased, and that of diastolic period decreased. 4. AIx rose by aging. 5. AW was significantly increased despite no changes in AT. Conclusions : By analyzing optimum pulse waveforms of 5-level graded pressure method, we could complement weakness of single graded pressure method. Also, possibility of applying the AW rate to risk assessment of hypertension or arteriosclerosis was confirmed in normotensive population which might not be assessed by AIx.

• 드라이브 ㆍ 컨트롤
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• 제13권4호
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• pp.14-22
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• 2016

This paper presents a stochastic and predictive working-risk-assessment algorithm for excavators based on a one-layer laser scanner. The one-layer laser scanner is employed to detect objects and to estimate an object's dynamic behaviors such as the position, velocity, heading angle, and heading rate. To estimate the state variables, extended and linear Kalman filters are applied in consideration of laser-scanner information as the measurements. The excavator's working area is derived based on a kinematic analysis of the excavator's working parts. With the estimated dynamic behaviors and the kinematic analysis of the excavator's working parts, an object's behavior and the excavator's working area such as the maximum, actual, and predicted areas are computed for a working risk assessment. The four working-risk levels are defined using the predicted behavior and the working area, and the intersection-area-based quantitative-risk level has been computed. An actual test-data-based performance evaluation of the designed stochastic and predictive risk-assessment algorithm is conducted using a typical working scenario. The results show that the algorithm can evaluate the working-risk levels of the excavator during its operation.

• Annals of Occupational and Environmental Medicine
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• 제35권
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• pp.3.1-3.11
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• 2023

Background: Studies on the risk of mercury (Hg) in Korean fishery products focus primarily on total Hg levels as opposed to methylmercury (MeHg) levels. None of the few studies on MeHg in tuna investigated tuna from Japanese restaurants. Few have evaluated lead (Pb), cadmium (Cd) and arsenic (As) in tuna. Thus, this study aimed to conduct a risk assessment by evaluating heavy metal concentrations in tuna from Japanese restaurants. Methods: Thirty-one tuna samples were collected from Japanese restaurants in the Republic of Korea. They were classified according to region and species. The concentration of heavy metals in the samples was analyzed using the Ministry of Food and Drug Safety Food Code method. The rate of exceedance of maximum residue levels (MRLs) and the risk compared to the provisional tolerable weekly intake (PTWI) set by the Joint Food and Agriculture Organization/World Health Organization Expert Committee on Food Additives (%PTWI) were evaluated for risk assessment. Results: The mean of MeHg, Pb, Cd and As concentrations were 0.56 ± 1.47 mg/kg, 33.95 ± 3.74 ㎍/kg, 14.25 ± 2.19 ㎍/kg and 1.46 ± 1.89 mg/kg, respectively. No sample exceeded the MRLs of Pb and Cd, but 9.7% of the samples exceeded the MRL of MeHg. The %PTWIs of MeHg, Pb, Cd and As were 4.2037, 0.0162, 0.0244 and 1.1627, respectively. The %PTWI of MeHg by age group and sex was highest among men aged 19-29 years (10.6494), followed by men aged 30-49 years (7.2458) and women aged 19-29 years (4.8307). Conclusions: We found that 3 out of 31 samples exceeded the MRL of MeHg. The %PTWI of MeHg showed significant differences based on age and sex, and the value was likely to exceed a safe level depending on individuals' eating behaviors. Therefore, improved risk management for MeHg is required.

• 환경영향평가
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• 제15권6호
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• pp.373-383
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• 2006

The spatial mapping of risk is very useful data in planning for disaster preparedness. This research presents a methodology for making the landslide life risk map in the Boeun area which had considerable landslide damage following heavy rain in August, 1998. We have developed a three-stage procedure in spatial data analysis not only to estimate the probability of the occurrence of the natural hazardous events but also to evaluate the uncertainty of the estimators of that probability. The three-stage procedure consists of: (i)construction of a hazard prediction map of "future" hazardous events; (ii) validation of prediction results and estimation of the probability of occurrence for each predicted hazard level; and (iii) generation of risk maps with the introduction of human life factors representing assumed or established vulnerability levels by combining the prediction map in the first stage and the estimated probabilities in the second stage with human life data. The significance of the landslide susceptibility map was evaluated by computing a prediction rate curve. It is used that the Bayesian prediction model and the case study results (the landslide susceptibility map and prediction rate curve) can be prepared for prevention of future landslide life risk map. Data from the Bayesian model-based landslide susceptibility map and prediction ratio curves were used together with human rife data to draft future landslide life risk maps. Results reveal that individual pixels had low risks, but the total risk death toll was estimated at 3.14 people. In particular, the dangerous areas involving an estimated 1/100 people were shown to have the highest risk among all research-target areas. Three people were killed in this area when landslides occurred in 1998. Thus, this risk map can deliver factual damage situation prediction to policy decision-makers, and subsequently can be used as useful data in preventing disasters. In particular, drafting of maps on landslide risk in various steps will enable one to forecast the occurrence of disasters.

• Journal of Radiation Protection and Research
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• 제28권3호
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• pp.189-197
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• 2003

Level 3 PSA(사고결말분석)는 원자력 발전소의 사고 시 누출된 방사성 핵종으로 인해 야기되는 환경 및 인체에 미치는 영향(공중위험도)을 평가하는 것이다. 본 논문에서는 원자력 발전소의 중대사고시 환경으로 방출되는 방사성물질의 방출특성과 그 결과로 인체에 미치는 영향에 대하여 확률론적 사고영향분석코드인 MACCS를 이용하여 평가하였다. 이러한 평가는 관련 변수들의 상대적 중요도를 파악하는데 유용할 뿐만 아니라 소외리스크(Offsite Risk)를 최소화시키기 위한 대책개발에 있어 중요한 지표가 될 수 있다. 특히 방출고도, 열 함량, 방출기간의 3가지 중요 변수를 선정하여, 이들 변수들의 변화에 따라 영향을 받는 조기사망자 수와 암 사망자 수의 변화를 분석하였다. 또한, 참조원전의 위험성 평가를 위하여 IPE(Individual Plant Examination)에서 제시된 STC(Source Term Category) 19가지 시나리오에 대한 각 사고별 빈도와 MACCS코드를 수행한 결과값을 이용하여 참조원전의 위험성 평가를 수행하였다.

• 한국환경보건학회지
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• 제32권5호
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• pp.522-531
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• 2006

This study has been conducted to evaluate the influence of ambient heavy metals to the air quality and to find their sources in Ulsan. Korea. The distribution characteristics of ambient heavy metals with wind direction were investigated by using pollution-rose diagram. Carcinogenic risk for five trace heavy metals (Pb. Cd, Cr, Mn, and Ni), which are classified to carcinogenic material by US EPA, are assessed according to the classification system of USEPA and WHO. According to pollution-rose calculation on pollutants sources, Pb and Cu in Deoksin, which is an adjacent to Onsan industrial complexes, were $0.1058\;and\;0.3242{\mu}g/m^3$. These concentration levels are the highest at all sampling sites. From this result we could confirm that it was affected by Onsan industrial complex that is located northeast of Deoksin.,And the maximum concentration of Cd, Cr, and Ni were $0.0306,\;0.0102,\;and\;0.0146\;{\mu}g/m^{3} in Yeocheon respectively. Because Yeocheon is in the Mipo industrial complexes, which have many combustors, incinerators, and manufacturing facilities compared to other regions. In carcinogenic risk assessment, Pb, Ni, and Mn concentration level at six sampling sites were lower than the risk level guideline values ($10^{-5}$) of WHO. However, $Cr^{6+}$ and Cd concentration in Yeocheon were 60% and 205% higher than the guideline values of WHO. Therefore it is very important that the emission from industrial complexes were carefully managed and controlled to improve air quality in residential area.

• 환경영향평가
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• 제5권1호
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• pp.47-60
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• 1996

지하수를 음용수로 공급시 질산오염문제는 한국을 포함한 세계의 여러나라에서 보고되어 왔다. 질산($NO_3$)은 청색증 유발물짙로서 뿐만 아니라 발암물질일 가능성도 동물실험을 통해 제기되고 있는 실정이다. 질산에 오염된 지하수로 인한 인체의 위해성을 감소시키기 위하여 여러 가지의 질산 위해성 관리 대책들은 개발될 수 있다. 이러한 여러가지의 대책들을 비교 평가할 때 기준이 되는 항목으로는 (1) 허용할 수 있는 인체의 위해도(Risk Level), (2) 비용, 그리고 (3) 적용하는 방법의 기술적 타당성을 들 수 있다. 그러나 불충분한 자료와 인간지식의 한계 때문에 각 기준항목을 대표하는 값의 대부분은 불확실성을 내포하게 된다. 본 논문에서는 의사결정권자들이 불확실성을 고려하면서 여러가지 대책들 중에서 최적의 대책을 선정하는데 이용하기 위한 다기준의사결정기법은 보여진다. 그리고 각 기준값의 불확실성을 표현하고 다기준의사결정기법과 불확실성을 결합시키기 위하여 퍼지집합이론(Fuzzy Set Theory)은 응용되어 진다.

• 대한인간공학회지
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• 제32권5호
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• pp.469-474
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• 2013

Objective: The purpose of this study was to analyze the risk factors of MSDs for the types of office work. Background: Physical risk factors of VDT(Video Display Terminal) associated with shoulder and neck musculoskeletal disorders(MSDs) include static work postures and workstation status. Method: In this study, office work was divided into data search, data entry and design work(drawings, etc.), and then we were surveyed 7 major work places which was included these works. We recorded working postures and obtained still images, depending on the types of office work. Then, RULA(Rapid Upper Limb Assessment) and ROSA(Rapid Office Strain Assessment) were used to analysis the risk factors. Results: The results of RULA showed that design work was under risk levels and required change, but ROSA showed that data entry and design work were high risk. The RULA is to evaluate the level of risk factors based on the working posture; on the other hand, the ROSA is to consider the use of peripheral, same as chair, keyboard/mouse, monitor and computer workstations. Conclusion: Conclusions of this study, the office work is necessary to identify the risk factors caused by the use of peripheral, as well as working posture.