• 한국안전학회지
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• 제26권5호
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• pp.99-104
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• 2011

An ILRT Interval for a nuclear power plant in Korea was extended from once in five years to once in ten years. Therefore, it is necessary to evaluate risk impact for ILRT interval extensions. In this paper, input data were generated for the reference plants, KSNP, using raw data such as meteorological data, population distribution data and source term data. And, using MACCS II code the risk impact assessment was performed based on the two methodologies of NUREG-1493 and NEI Interim Report. The risk impact derived from an ILRT interval extension was identified not to be significant. It is considered to apply this study and results to making an accident management plan and safety goal, and to the field of public acceptance.

• Asian Pacific Journal of Cancer Prevention
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• 제15권5호
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• pp.2257-2262
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• 2014

A series of studies have explored the role of cytosolic serine hydroxymethyltransferase (SHMT1) C1420T polymorphism in cancer risk, but their results were conflicting rather than conclusive. To derive a more precise estimation of the association between C1420T and cancer risk, the present meta-analysis of 28 available studies with 15,121 cases and 18,023 controls was conducted. The results revealed that there was no significant association between the polymorphism and cancer risk overall. In stratified analysis by cancer type (breast cancer, gastrointestinal cancer, leukemia, lymphoma, and others), the results showed that 1420T allele was associated with decreased risk in leukemia (CT vs. CC: OR= 0.825, 95% CI =0.704-0.966; and CT+TT vs. CC: OR= 0.838, 95% CI = 0.722-0.973), but the same results were not present for other cancer types. When subgroup analysis was performed by source of control (population-based [PB] and hospital-based [HB]), a borderline inverse association was observed for the HB subgroup (CT vs. CC: OR= 0.917, 95% CI = 0.857-0.982) but not for the PB subgroup. Stratifying by geographic area (America, Asia and Europe), significant inverse association was only found in Asia subgroup (CT vs. CC: OR= 0.674, 95% CI = 0.522-0.870). In summary, the findings suggest that SHMT1 C1420T polymorphism is not associated with overall cancer development, but might decrease cancer susceptibility of Asians as well as reduce leukemia risk. Large well-designed epidemiological studies will be necessary to validate the risk identified in the current meta-analysis.

• 한국물환경학회지
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• 제26권4호
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• pp.629-636
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• 2010

According to the spatial movements of the Nak-dong river watershed, the changes in heavy metal concentrations were simulated by WASP7.3. The risk assessment was performed using the predicted data of WASP7.3. The target heavy metal was manganese (Mn). In the simulated manganese data of WASP7.3, the average concentration by regions was from 0.03 mg/L to 0.07 mg/L. It is lower than drinking water standard in korea. The risk assessment was presented that it was high at the junction of Nak-dong river and Kumho river. It was influenced by the discharge of industrial complexes and large cities which were located in the junction. In comparison of drinking water standard and predicted data of WASP7.3 risk assessment, whole watershed was also low level at predicted data. However, to keep the similar risk value ($10^{-7}$) in adults and children anywhere, it requires the additional treatment of the point source discharges. It was also reflected by regions. Through this study, it was possible to evaluate heavy metal influence in unattainable monitoring regions and to estimate heavy metal addition and reduction by locations. Therefore, the outcomes of WASP7.3 can connect with the risk assessment and it can evaluate the safety of human by regions.

• 대한방사선기술학회지:방사선기술과학
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• 제45권6호
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• pp.553-560
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• 2022

The purpose of this study is to evaluate the clinical risk according to the applicator heterogeneity, mislocation, and tissue heterogeneity correction through a dose verification program during brachytherapy of cervical cancer. We performed image processing with MATLAB on images acquired with CT simulator. The source was modeled and stochiometric calibration and Monte-Carlo algorithm were applied based on dwell time and location to calculate the dose, and the secondary cancer risk was evaluated in the dose verification program. The result calculated by correcting for applicator and tissue heterogeneity showed a maximum dose of about 25% higher. In the bladder, the difference in excess absolute risk according to the heterogeneity correction was not significant. In the rectum, the difference in excess absolute risk was lower than that calculated by correcting applicator and tissue heterogeneity compared to the water-based calculation. In the femur, the water-based calculation result was the lowest, and the result calculated by correcting the applicator and tissue heterogeneity was 10% higher. A maximum of 14% dose difference occurred when the applicator mislocation was 20 mm in the Z-axis. In a future study, it is expected that a system that can independently verify the treatment plan can be developed by automating the interface between the treatment planning system and the dose verification program.

• 한국환경보건학회지
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• 제50권2호
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• pp.125-137
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• 2024

Background: The Korea Risk Information Surveillance System (K-RISS) was developed to enable the early detection of food and drug safety-related issues. Its goal is to deliver real-time risk indicators generated from ongoing food and drug risk monitoring. However, the existing K-RISS system suffers under several limitations. Objectives: This study aims to augment K-RISS with more detailed indicators and establish a severity standard that takes into account structural changes in the daily time series of K-RISS values. Methods: First, a Delphi survey was conducted to derive the required weights. Second, a control chart, commonly used in statistical process controls, was utilized to detect outliers and establish caution, attention, and serious levels for K-RISS values. Furthermore, Bai and Perron's method was employed to determine structural changes in K-RISS time series. Results: The study incorporated 'closeness to life' and 'sustainability' indicators into K-RISS. It obtained the necessary weights through a survey of experts for integrating variables, combining indicators by data source, and aggregating sub K-RISS values. We defined caution, attention, and serious levels for both average and maximum values of daily K-RISS. Furthermore, when structural changes were detected, leading to significant variations in daily K-RISS values according to different periods, the study systematically verified these changes and derived respective severity levels for each period. Conclusions: This study enhances the existing K-RISS system and introduces more advanced indicators. K-RISS is now more comprehensively equipped to serve as a risk warning index. The study has paved the way for an objective determination of whether the food safety risk index surpasses predefined thresholds through the application of severity levels.

• 품질경영학회지
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• 제49권3호
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• pp.299-312
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• 2021

Purpose: We provide a condition-based maintenance policy where a surrogate variable is used for monitoring system performance. We constructed a risk function by taking into account the risk and losses accompanied with erroneous decisions. Methods: Assuming a unique degradation process for the performance variable and its specific relationship with the surrogate variable, the maintenance policy is determined. A risk function is developed on the basis of producer's and consumer's risks accompanied with each decision. With a strategic safety factor considered, the optimal threshold value for the surrogate variable is determined based on the risk function. Results: The condition-based maintenance is analyzed from the point of risk. With an assumed safety consideration, the optimal threshold value of the surrogate variable is provided for taking a maintenance action. The optimal solution cannot be obtained in a closed form. An illustrative numerical example and solution is provided with a source code of R program. Conclusion: The study can be applied to situation where a sensor signal is issued if the system performance begins to degrade gradually and reaches eventually its functional failure. The study can be extended to the case where two or more performance variables are connected to a same surrogate variable. Also estimation of the distribution parameters and risk coefficients should be further studied.

• 정보보호학회논문지
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• 제31권4호
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• pp.779-791
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• 2021

보통의 웹 서비스는 불특정 다수에게 허용을 해야하는 접근 통제 정책으로 인하여, 지속적으로 해커들의 공격 대상이 되어 왔다. 이러한 상황에 대응하고자 기업들은 주기적으로 웹 취약점 점검을 실시하고, 발견된 취약점의 위험도에 따라 조치를 취하고 있다. 이러한 웹 취약점 위험도는 국내외 유관기관의 사전 통계 및 자체적인 평가를 통해 산정되어 있다. 하지만 웹 취약점 점검은 보안설정 및 소스코드 등의 정적 진단과는 달리 동적 진단으로 이루어진다. 동일한 취약점 항목일지라도 다양한 공격 결과를 도출할 수 있으며, 진단 대상 및 환경에 따라 위험도가 달라질 수 있다. 이러한 점에서 사전 정의된 위험도는 실제 존재하는 취약점의 위험도와는 상이할 수 있다. 본 논문에서는 이러한 점을 개선하고자 사이버 킬체인 중심으로 공격 결과 기반의 웹 취약점 위험도 평가 모델을 제시한다.

• Journal of Korean Neurosurgical Society
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• 제48권5호
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• pp.399-405
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• 2010

Objective : Patients with spontaneous intracerebral hemorrhage (ICH) presenting within 24 hours of symptom onset are known to be increased risk of hematoma expansion which is closely correlated with morbidity and mortality. We investigated whether tiny enhancing foci ('Spot sign') on axial view of 3-dimensional computed tomography angiography (3D-CTA) source images can predict subsequent hematoma expansion in spontaneous ICH. Methods : During a 2-year period (March 2007-March 2009), we prospectively evaluated 3D-CTA of 110 patients with spontaneous ICH. Based on source images of 3D-CTA, patients were classified according to presence or absence of 'Spot sign'; 'Spot sign' (+) group, 'Spot sign' (-) group. Radiological factors and clinical outcomes were compared between two groups. Results : Hematoma expansion occurred in 16 patients (15%). Mean Glasgow Coma Scale (GCS) score of patients with hematoma expansion was significantly different compared to score of patients without hematoma expansion (5 vs. 9, P < 0.001). Nineteen patients (16%) of 110 ICH patients demonstrated 'spot sign' on 3D-CTA. Among the 'spot sign' (+) group, 53% of patients developed hematoma expansion. Conversely 7% of patients without 'spot sign' demonstrated the hematoma expansion (p < 0.001). Initial volume and location of hematoma were significantly not associated with hematoma expansion except shape of hematoma. Conclusion : Our study showed that patients with hematoma expansion of spontaneous ICH had significant clinical deterioration. And the fact that 'spot sign' (+) group have higher risk of hematoma expansion suggests the presence of 'spot sign' on source images of 3D-CTA can give a clue to predict hematoma expansion in spontaneous ICH.

• Journal of Korean Neurosurgical Society
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• 제59권4호
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• pp.368-373
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• 2016

Objective : Delayed hinge fracture (HF) that develops after cervical open door laminoplasty can be a source of postoperative complications such as axial pain. However, risk factors related to this complication remain unclear. We performed a retrospective clinical series to determine risk factors for delayed HF following plate-only open-door cervical laminoplasty. Methods : Patients who underwent plate-only open-door laminoplasty and had available postoperative computed tomography (CT) scans (80 patients with 270 laminae) were enrolled. Hinge status, hinge gutter location, open location, hinge width, number of screws used, operation level, and open angle were observed in the CT to determine radiographic outcome. Demographic data were collected as well. Radiographic and clinical parameters were analyzed using univariate and multivariate logistic regression analysis to determine the risk factors for HF. Results : Univariate logistic regression analysis results indicated poor initial hinge status, medially placed hinge gutter, double screw fixation on the elevated lamina, upper surgical level, and wide open angle as predictors for HF (p<0.05). Initial hinge status seemed to be the most powerful risk factor for HF (p=0.000) and thus was collinear with other variables. Therefore, multivariate logistic regression analysis was performed excluding initial hinge status, and the results indicated that medially placed hinge gutter, double screw fixation on the elevated lamina, and upper surgical level were risk factors for HF after adjustment for other confounding factors. Conclusion : To prevent HF and to draw a successful postoperative outcome after cervical laminoplasty, surgical and clinical precautions should be considered.

• 정보보호학회논문지
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• 제25권4호
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• pp.829-838
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• 2015

스마트 폰의 보급이 확대됨에 따라 많은 종류의 악성코드가 등장하였다. 이 중 스파이웨어는 기존과 다르게 운영체제가 제공하는 기능을 보안 정책에 따라 사용자의 동의를 정상적으로 획득하여 설치된다. 하지만 사용자가 의도하지 않은 기능을 내포하고 있는 스파이웨어는 기존의 악성코드 감지방법으로 쉽게 잡아내지 못하고 있다. 이러한 상황에서 본 논문은 스파이웨어 중 도청을 감지하는 연구를 진행하였으며, 스파이웨어가 가진 문제를 해결하기 위한 새로운 접근을 통해 도청 감지 모델과 이를 실행하는 어플리케이션을 개발했다. 음성 도청을 판별하기 위해서 각 어플리케이션별 전력 사용량 도출 기능, 모듈별 전력 사용량 도출 기능, 네트워크 사용량 감지를 수행하였다. 전력 사용량 도출을 위한 Open Source Project인 Power Tutor에 네트워크 사용량 감지 기능을 추가하였으며, 여기서 측정 및 수집된 데이터를 알고리즘을 거쳐 도청 위험도를 판별했다. 또한 이 논문에서 구축된 어플리케이션은 데이터 수집, 데이터 분석, 그리고 위험군 산출을 통해 도청 위험군을 감지한다. 어플리케이션을 스마트 폰에 설치하여 데이터의 측정 및 수집을 진행하였으며, 도청 시뮬레이션을 위해 Vice Application을 Background로 하여 사용하였다.