• Korean Journal of Construction Engineering and Management
• /
• v.2 no.2 s.6
• /
• pp.90-97
• /
• 2001

The paper considers non-deterministic methods of analysing the risk exposure in a cost estimate. The method(referred to as the 'Monte Carlo simulation' method) interprets cost data indirectly, to generate a probability distribution for total costs from the deficient elemental experience cost distribution. The Monte Carlo method is popular method for incorporating uncertainty relative to parameter values in risk assessment modelling. Non-deterministic methods, they are here presented as possibly effective foundation on which to risk management in cost estimating. The objectives of this research is to develop a computerized algorithms to forecast the probabilistic total construction cost and the elemental work cost at the planning stage.

• Nuclear Engineering and Technology
• /
• v.49 no.2
• /
• pp.426-433
• /
• 2017

This paper describes the development process, the innovative techniques used and insights gained from the latest integrated, full scope, multistate Level 2 PSA analysis conducted at the Leibstadt Nuclear Power Plant (KKL), Switzerland. KKL is a modern single-unit General Electric Boiling Water Reactor (BWR/6) with Mark III Containment, and a power output of $3600MW_{th}/1200MW_e$, the highest among the five operating reactors in Switzerland. A Level 2 Probabilistic Safety Assessment (PSA) analyses accident phenomena in nuclear power plants, identifies ways in which radioactive releases from plants can occur and estimates release pathways, magnitude and frequency. This paper attempts to give an overview of the advanced modeling techniques that have been developed and implemented for the recent KKL Level 2 PSA update, with the aim of systematizing the analysis and modeling processes, as well as complying with the relatively prescriptive Swiss requirements for PSA. The analysis provides significant insights into the absolute and relative importances of risk contributors and accident prevention and mitigation measures. Thanks to several newly developed techniques and an integrated approach, the KKL Level 2 PSA report exhibits a high degree of reviewability and maintainability, and transparently highlights the most important risk contributors to Large Early Release Frequency (LERF) with respect to initiating events, components, operator actions or seismic component failure probabilities (fragilities).

• Safety and Health at Work
• /
• v.9 no.4
• /
• pp.416-420
• /
• 2018

Background: Urinary 1-hydroxypyrene (1-OHP) has been widely used as a biomarker of polycyclic aromatic hydrocarbons (PAHs) in occupationally exposed workers. The objective of this study is to investigate the concentration of urinary 1-OHP among charcoal workers as subjects and non-charcoal workers as controls. Methods: Early morning urine samples were collected from 68 persons (25 charcoal workers in Igbo-Ora, 20 charcoal workers in Alabata, and 23 non-charcoal workers) who volunteered to participate in this study. 1-OHP determination in urine samples was carried out using high performance liquid chromatography after hydrolysis. Descriptive and inferential statistics were used for data analysis at p < 0.05. Results: The mean urinary 1-OHP concentration (${\mu}mol/mol$ creatinine) among charcoal workers at Igbo-Ora and Alabata and non-charcoal workers were $2.22{\pm}1.27$, $1.32{\pm}0.65$, and $0.32{\pm}0.26$ (p < 0.01). There existed a relationship between respondent type and 1-OHP concentration. Charcoal workers were 3.14 times more at risk of having 1-OHP concentrations that exceed the American Conference of Governmental Industrial Hygienists guideline of $0.49{\mu}mol/mol$ creatinine than non-charcoal workers (relative risk = 3.14, 95% confidence interval: 1.7-5.8, p < 0.01). Conclusion: Charcoal workers are exposed to PAHs during charcoal production and are at risk of experiencing deleterious effects of PAH exposure. Routine air quality assessment should be carried out in communities where charcoal production takes place. Assessment of urinary 1-OHP concentration and use of personal protective equipment should also be encouraged among charcoal workers.

• Korean Journal of Remote Sensing
• /
• v.38 no.5_2
• /
• pp.781-791
• /
• 2022

It is crucial to provide forest fire risk forecast information to minimize forest fire-related losses. In this research, forecast models of forest fire risk at a mid-range (with lead times up to 7 days) scale were developed considering past, present and future conditions (i.e., forest fire risk, drought, and weather) through random forest machine learning over South Korea. The models were developed using weather forecast data from the Global Data Assessment and Prediction System, historical and current Fire Risk Index (FRI) information, and environmental factors (i.e., elevation, forest fire hazard index, and drought index). Three schemes were examined: scheme 1 using historical values of FRI and drought index, scheme 2 using historical values of FRI only, and scheme 3 using the temporal patterns of FRI and drought index. The models showed high accuracy (Pearson correlation coefficient >0.8, relative root mean square error <10%), regardless of the lead times, resulting in a good agreement with actual forest fire events. The use of the historical FRI itself as an input variable rather than the trend of the historical FRI produced more accurate results, regardless of the drought index used.

• The Journal of Korean Medicine
• /
• v.24 no.4
• /
• pp.19-24
• /
• 2003

Background and Purposes : Smoking is a well-known risk factor for ischemic stroke. It may contribute to s1Toke by inducing the aggregation of platelets and formation of atheroma, reducing cerebral blood flow, and increasing fibrinogen. However, the relative risk varies according to different ethnicity and area. Therefore, we performed this study to assess the risk of smoking for ischemic s1Toke in Korea. Methods : Cigarette smoking habit was studied in 308 patients with ischemic s1Toke and in 348 age- and sex-matched control subjects who had no history of stroke using case control methods. In multiple logistic regression analysis, smoking had a significant value of odds ratio adjusted for hypertension, diabetes mellitus, and hyperlipidemia. Results : The adjusted odds ratio (AOR) and 95％ confidence interval (CI) was significant in the medium smokers (AOR, 1.92; 95％ CI, 1.11 to 3.33: p< 0.05) and heavy smokers (AOR, 2.80; 95％ CI, 1.64 to 4.78: p< 0.05). Furthermore, the OR was higher in hypertensive subjects than in normotensive subjects compared to non-smokers (AOR, 1.98; 95％ CI, 1.01 to 3.85: p< 0.05). Conclusions : Our findings suggest that smoking is an independent risk factor for ischemic stroke in Korea.

• Fire Science and Engineering
• /
• v.19 no.1 s.57
• /
• pp.20-28
• /
• 2005

Major petrochemical companies in the USA and the EU map out the strategies step-by-step hazard evaluation for the efficient risk management. They adopted the risk screening methods, such as Dow fire & explosion index, as a preliminary phase to execute detailed evaluation such as QRA (Quantitative Risk Assessment). In this study, The FEDI (Fire & Explosion Damage Index), which a kind of risk screening method proposed by Khan and Abbasi, was applied to the BTX plant in Korea. We showed that the FEDI can be effectively used to classify the hazard potential by comparison of the result from the FEDI and the result from QRA. And we showed that the characteristics and the quantities of chemical are the factors which have a largest effect on fire and explosion by executing relative sensitivity analysis of the FEDI. In conclusion, if the FEDI was applied as a preliminary phase of HAZOP, more efficient hazard evaluation can be possible.

• Safety and Health at Work
• /
• v.5 no.1
• /
• pp.27-31
• /
• 2014

Background: Carpal tunnel syndrome (CTS) is a common work-related peripheral neuropathy. In addition to grip force and repetitive hand exertions, wrist posture (hyperextension and hyperflexion) may be a risk factor for CTS among workers. However, findings of studies evaluating the relationship between wrist posture and CTS are inconsistent. The purpose of this paper was to conduct a meta-analysis of existing studies to evaluate the evidence of the relationship between wrist posture at work and risk of CTS. Methods: PubMed and Google Scholar were searched to identify relevant studies published between 1980 and 2012. The following search terms were used: "work related", "carpal tunnel syndrome", "wrist posture", and "epidemiology". The studies defined wrist posture as the deviation of the wrist in extension or flexion from a neutral wrist posture. Relative risk (RR) of individual studies for postural risk was pooled to evaluate the overall risk of wrist posture on CTS. Results: Nine studies met the inclusion criteria. All were cross-sectional or case-control designs and relied on self-report or observer's estimates for wrist posture assessment. The pooled RR of work-related CTS increased with increasing hours of exposure to wrist deviation or extension/flexion [RR = 2.01; 95% confidence interval (CI): 1.646-2.43; p < 0.01: Shore-adjusted 95% CI: 1.32-2.97]. Conclusion: We found evidence that prolonged exposure to non-neutral wrist postures is associated with a twofold increased risk for CTS compared with low hours of exposure to non-neutral wrist postures. Workplace interventions to prevent CTS should incorporate training and engineering interventions that reduce sustained non-neutral wrist postures.

• Journal of Environmental Health Sciences
• /
• v.49 no.6
• /
• pp.362-371
• /
• 2023

Background: PM_2.5 pollution has been a persistent problem in South Korea, with concentrations consistently exceeding World Health Organization (WHO) guidelines. The aging of the population in the country further exacerbates the health impacts of PM_2.5 since older adults are more susceptible to the adverse effects of air pollution. Objectives: This study aims to evaluate how the health impact (premature death) due to long-term exposure to PM_2.5 in South Korea could change in the future according to the trend of change in the country's population structure. Methods: The study employs a relative risk function, which accounts for age-specific relative risks, to assess the changes in premature deaths by age and region at the average annual PM_2.5 concentration for 2022 and at PM_2.5 concentration improvement levels. Premature deaths were estimated using the Global Exposure Mortality Model (GEMM). Results: The findings indicate that the increase in premature deaths resulting from the projected population structure changes up to 2050 would significantly outweigh the health benefits (reduction in premature deaths) compared to 2012. This is primarily attributed to the rising number of premature deaths among the elderly due to population aging. Furthermore, the study suggests that the effectiveness of the current domestic PM_2.5 standard would be halved by 2050 due to the increasing impact of population aging on PM_2.5-related mortality. Conclusions: The study highlights the importance of considering trends in population structure when evaluating the health benefits of air pollution reduction measures. By comparing and evaluating the health benefits in reflection of changes in population structure to the predicted PM_2.5 concentration improvements at the provincial level, a more comprehensive assessment of regional air quality management strategies can be achieved.

• The Korean journal of internal medicine
• /
• v.39 no.3
• /
• pp.501-512
• /
• 2024

Background/Aims: Optimal risk stratification based on simplified geriatric assessment to predict treatment-related toxicity and survival needs to be clarified in older patients with diffuse large B-cell lymphoma (DLBCL). Methods: This multicenter prospective cohort study enrolled newly diagnosed patients with DLBCL (≥ 65 yr) between September 2015 and April 2018. A simplified geriatric assessment was performed at baseline using Activities of Daily Living (ADL), Instrumental ADL (IADL), and Charlson's Comorbidity Index (CCI). The primary endpoint was event-free survival (EFS). Results: The study included 249 patients, the median age was 74 years (range, 65-88), and 125 (50.2%) were female. In multivariable Cox analysis, ADL, IADL, CCI, and age were independent factors for EFS; an integrated geriatric score was derived and the patients stratified into three geriatric categories: fit (n = 162, 65.1%), intermediate-fit (n = 25, 10.0%), and frail (n = 62, 24.9%). The established geriatric model was significantly associated with EFS (fit vs. intermediate-fit, HR 2.61, p < 0.001; fit vs. frail, HR 4.61, p < 0.001) and outperformed each covariate alone or in combination. In 87 intermediate-fit or frail patients, the relative doxorubicin dose intensity (RDDI) ≥ 62.4% was significantly associated with worse EFS (HR, 2.15, 95% CI 1.30-3.53, p = 0.002). It was related with a higher incidence of grade ≥ 3 symptomatic non-hematologic toxicities (63.2% vs. 27.8%, p < 0.001) and earlier treatment discontinuation (34.5% vs. 8.0%, p < 0.001) in patients with RDDI ≥ 62.4% than in those with RDDI < 62.4%. Conclusions: This model integrating simplified geriatric assessment can risk-stratify older patients with DLBCL and identify those who are highly vulnerable to standard dose-intensity chemoimmunotherapy.

• Korean Journal of Clinical Pharmacy
• /
• v.25 no.2
• /
• pp.80-93
• /
• 2015

Objective: Pegfilgrastim is recently introduced that is long acting G-CSF for prophylaxis of febrile neutropenia. Treatment of non-Hodgikin's lymphoma (NHL) with R-CHOP is classified with relative high risk of febrile neutropenia. The study evaluated the prophylactic effect of pegfilgrastim to reduce the incidence of febrile neutropenia associated with R-CHOP of patient in NHL. And the risk factors associated with the incidence of FN and related events were evaluated. Methods: This retrospective study reviews the Electronic Medical Record of 68 NHL patients who received R-CHOP chemotherapy in single center between September 2013 and August 2014. These patients were classified who receive prophylaxis pegfilgrastim or no prophylaxis. Results: Sixty eight patients received R-CHOP with NHL. In 144 cycles of patients receiving pegfilgrastim, compared with no prophylaxis 178 cycles, had a lower incidence of febrile neutropenia (5.5% vs. 23.6%, p = 0.001), grade 3 or grade 4 neutropenia (14.4% vs. 89.8%, p < 0.001) and neutropenia related events (p < 0.05). The risk of febrile neutropenia after prophylaxis was significantly associated with age ${\geq}65$ (OR: 5.87, 95% CI 1.07-32.27, p = 0.042), $IPI{\geq}3$ (OR: 7.2, 95% CI 1.31-39.6, p = 0.023), S.alb < 3.5 g/dL (OR: 31.01, 95% CI 6.32-152.17, p < 0.0001). In multiple logistic regression analysis, lower baseline serum albumin (OR: 21.1, 95% CI 3.8-116.98, p = 0.001) was significantly associated with occurrence of febrile neutropenia. Conclusion: The study recommends prophylactic pegfilgrastim through risk assessment of febrile neutropenia in patients with non-Hodgikin's lymphoma receiving R-CHOP.