• Radiation Oncology Journal
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• 제36권2호
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• pp.139-146
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• 2018

Purpose: IBTR! 2.0 nomogram is web-based nomogram that predicts ipsilateral breast tumor recurrence (IBTR). We aimed to validate the IBTR! 2.0 using an external data set. Materials and Methods: The cohort consisted of 2,206 patients, who received breast conserving surgery and radiation therapy from 1992 to 2012 at our institution, where wide surgical excision is been routinely performed. Discrimination and calibration were used for assessing model performance. Patients with predicted 10-year IBTR risk based on an IBTR! 2.0 nomogram score of <3%, 3%-5%, 5%-10%, and >10% were assigned to groups 1, 2, 3, and 4, respectively. We also plotted calibration values to observe the actual IBTR rate against the nomogram-derived 10-year IBTR probabilities. Results: The median follow-up period was 73 months (range, 6 to 277 months). The area under the receiver operating characteristic curve was 0.607, showing poor accordance between the estimated and observed recurrence rate. Calibration plot confirmed that the IBTR! 2.0 nomogram predicted the 10-year IBTR risk higher than the observed IBTR rates in all groups. High discrepancies between nomogram IBTR predictions and observed IBTR rates were observed in overall risk groups. Compared with the original development dataset, our patients had fewer high grade tumors, less margin positivity, and less lymphovascular invasion, and more use of modern systemic therapies. Conclusions: IBTR! 2.0 nomogram seems to have the moderate discriminative ability with a tendency to over-estimating risk rate. Continued efforts are needed to ensure external applicability of published nomograms by validating the program using an external patient population.

• Journal of Radiation Protection and Research
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• 제35권1호
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• pp.6-11
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• 2010

Embodying the safety of radioactive waste disposal requires the relevant safety criteria and the corresponding stylized methods to demonstrate its compliance with the criteria. This paper proposes a conceptual model of risk-based safety evaluation for integrating complex potential radiation exposure situations in radioactive waste disposal. For demonstrating compliance with a risk constraint, the approach deals with important exposure scenarios from the viewpoint of the receptor to estimate the resulting risk. For respective exposure situations, it considers the occurrence probabilities of the relevant exposure scenarios as their probability of giving rise to doses to estimate the total risk to a representative person by aggregating the respective risks. In this model, an exposure scenario is simply constructed with three components:radionuclide release, radionuclide migration and environment contamination, and interaction between the contaminated media and the receptor. A set of exposure scenarios and the representative person are established from reasonable combinations of the components, based on a balance of their occurrence probabilities and the consequences. In addition, the probability of an exposure scenario is estimated on the assumption that the initiating external factors influence release mechanisms and transport pathways, and its effect on the interaction between the environment and the receptor may be covered in terms of the representative person. This integrated approach enables a systematic risk assessment for complex exposure situations of radioactive waste disposal and facilitates the evaluation of compliance with risk constraints.

• 수산해양기술연구
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• 제60권2호
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• pp.170-178
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• 2024

This study aimed to quantitatively analyze the risk using data from 329 safety accidents that occurred in aquaculture fisheries management vessels over the recent five years (2018-2022). For quantitative risk analysis, the Bayesian network proposed by the International Maritime Organization (IMO) was used to analyze the risk level according to the fishing process and cause of safety accidents. Among the work processes, the fishing process was analyzed to have the highest risk, being 12.5 times that of the navigation, 2.7 times that of the maintenance, and 8.8 times that of the loading and unloading. Among the causes of accidents, the hull and working environment showed the highest risk, being 1.7 times that of fishing gear and equipment, 4.7 times that of machinery and equipment, and 9.4 times that of external environment. By quantitatively analyzing the safety accident risks for 64 combinations of these four work processes and four accident causes, this study provided fundamental data to reduce safety accidents occurring in aquaculture fisheries management vessels.

• 대한족부족관절학회지
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• 제23권4호
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• pp.189-195
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• 2019

Purpose: The aim of this study is to evaluate if the Ilizarov external fixation procedure with axial compression can help to obtain fusion across the ankle joint in patients with a high risk of nonunion. Materials and Methods: From January 2006 to December 2015, the study reviewed 17 patients who underwent ankle arthropathy with a high risk of nonunion and who underwent ankle fusion using the Ilizarov external fixator with axial compression and auto bone grafting. After the lateral surface of the ankle joint was exposed through a lateral trans-fibular approach, massive removal of the articular cartilage and excision of any loose or avascular bone were done. With the cortical bone harvested from the pelvis as corticocancellous bone blocks, we inserted the two cortical blocks longitudinally into the anterior and posterior part of the free ankle space from lateral to medial to make the rectangular chamber to fill the cancellous bones. After the Ilizarov external fixator was equipped, we tightened the frame by 5 mm to compress the bone graft space. We accessed the American Orthopaedic Foot and Ankle Society (AOFAS) AnkleHindfoot score both preoperatively and postoperatively. Results: The average age at the time of operation was 63.4 years (range, 47~78 years). The mean frame time was 17.4 weeks (range, 15~23 weeks). The average follow-up period was 3.7 years (range, 2~6 years). Osseous fusion was obtained in 15 patients (88.2%). There were two stable pseudarthroses among the rheumatoid arthritis patients, and we continued their follow-up. The mean AOFAS AnkleHindfoot score improved from 48.5 to 73.7 points. Conclusion: Ankle arthrodesis using the Ilizarov external fixation with axial compression and auto bone grafting on the ankle arthropathy that had difficult conditions to achieve union is considered one of the useful methods with a correspondingly low incidence of complications.

• 한국항해항만학회지
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• 제36권4호
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• pp.321-327
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• 2012

Logistics in a supply chain network has become an important operational strategy in a competitive market. A number of internal and external risks involved in the logistics operations in a company tend to create problems in fulfilling customer orders. This research presents how ERM (enterprise risk management) can be used to identify, assess, and control logistics risks. An electronic company's logistics activities were used as an industry case to demonstrate a way to identify and assess risks surrounding global logistics function. This paper has further presented action plans to mitigate the impact of the risks that occur.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 추계학술대회 논문집
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• pp.581-586
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• 2005

In this study, a hazard list is developed for accidents/incidents of Korean railway through identification of the risk sources. The risk sources are classified by the progress of the accidents/incidents, which consists of cause, triggering event, and failure of the safety system. The hazard list of railway accidents/incidents of Korea is then developed through extensive review of both domestic and foreign data for railway accidents/incidents risk sources. The list is refined for each of six subsystems of the railway system, which includes safety management system, operation management, human error and qualification management, installations and equipments, external hazard, and railway level crossing.

• 한국IT서비스학회지
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• 제10권1호
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• pp.135-149
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• 2011

In this paper, we propose the high-risk group detection model for patients with high blood pressure using case-based reasoning. The proposed model can be applied for public health maintenance organizations to effectively manage knowledge related to high blood pressure and efficiently allocate limited health care resources. Especially, the focus is on the development of the model that can handle constraints such as managing large volume of data, enabling the automatic learning to adapt to external environmental changes and operating the system on a real-time basis. Using real data collected from local public health centers, the optimal high-risk group detection model was derived incorporating optimal parameter sets. The results of the performance test for the model using test data show that the prediction accuracy of the proposed model is two times better than the natural risk of high blood pressure.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2004년도 추계학술대회
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• pp.343-348
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• 2004

신세계는 테러리스트에 의한 세계무역센터의 공격으로 인해 테러로부터의 안전과 보호를 강화하기 위해 초점이 맞추어져 있다. 본 연구는 해상테러 위험요소의 구조와 우선순위를 분석하고자 한다. 이를 위해 먼저 테러의 유형과 사례를 토대로 브레인스토밍법을 이용하여 해상테러 위험요소를 추출하였고, 퍼지구조모델법을 이용하여 위험요소를 그래프로 구조화 하였으며, 계층분석법을 이용하여 위험요소간의 우선순위를 분석하였다. 그 결과 외부영향이 가장 큰 것으로 나타났다.

• 환경영향평가
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• 제19권3호
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• pp.259-270
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• 2010

We conducted human risk assessment for exposure to inhalation of chemical substances emitted from the storage tanks of petroleum refineries. To assess human risk, this study calculated chemical emissions from the external floating roofs on storage tank at petroleum refineries, as well as concentrations thereof in the ambient air using the K-SCREEN model, and then determined risk in accordance with the Reference Concentration (RfC) values and Inhalation Unit Risk criteria developed by the US Environmental Protection Agency. The results indicated that non-carcinogenic chemicals have a hazard quotient of less than 1, meaning they have an insignificant effect on human health for residential areas near the storage tanks. Among the known carcinogens, the hazard risk for benzene slightly exceeded $10^{-6}$, indicating the need for corrective reduction measures. The methodology for health impact assessment devised herein provides findings useful in decision making for policy makers and the general public with respect to construction of industrial complexes. However, the methodology proposed herein does have limitations, including discrepancy in results induced by use of U.S. data (due to the lack of usable domestic data). More systematic studies from related researchers will be needed to address these issues and produce more reliable outcomes.

• 한국항해항만학회지
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• 제29권6호
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• pp.487-493
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• 2005

전 세계는 테러리스트에 의한 세계무역센터의 공격으로 인해 테러로부터의 안전과 보호를 강화하기 위해 초점이 맞추어져 있다. 본 연구는 해상테러 위험요소의 구조와 우선순위를 분석하고자 한다. 이를 위해 먼저 테러의 유형과 사례를 토대로 브레인스토밍법을 이용하여 해상테러 위험요소를 추출하였고, 퍼지구조모델법을 이용하여 위험요소를 그래프로 구조화 하였으며, 계층분석법을 이용하여 위험요소간의 우선순위를 분석하였다. 그 결과 외부영향이 가장 큰 위험요소인 것으로 나타났다.