• International Journal of Computer Science & Network Security
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• 제23권6호
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• pp.77-83
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• 2023

This research is conducted to minimize the potential security risks of conducting online exams to an acceptable level as vulnerabilities and threats to this type of exam are presented. This paper provides a general structure for the risk management process and some recommendations for increasing the level of security.

• 아태비즈니스연구
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• 제15권1호
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• pp.1-14
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• 2024

Purpose - We investigate whether a potential missing pricing factor plays a significant role in the idiosyncratic volatility puzzle. Design/methodology/approach - We theoretically show how a missing pricing factor can affect the idiosyncratic volatility puzzle, and also show how to get around the problem empirically. We adopt the Fama-French five factor model for the estimation of the idiosyncratic risk and use randomly constructed portfolios as test assets. Findings - We find that a missing factor does not drive the idiosyncratic volatility puzzle. Thus, we conclude that the idiosyncratic volatility does affect the risk premium of its stock. Research implications or Originality - The Fama-French five factor model does a pretty good job in explaining the risk premiums of stocks, and it can be used to reliably estimate idiosyncratic risk of stocks.

• 터널과지하공간
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• 제27권2호
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• pp.89-99
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• 2017

이산화탄소 지중저장 사업의 성공적인 수행을 위해서는 저장시스템의 안정성을 확보할 수 있는 대상 지층을 선정하고 현장 지질조건에 최적화된 주입 조건을 설계해야 한다. 본 연구에서는 국내 실증실험 대상 예상후보지의 하나인 장기분지의 지질구조를 바탕으로 2차원 간략해석모델을 구축하고 TOUGH-FLAC 연계해석기법을 사용하여 초기응력조건과 주입량이 이산화탄소 격리저장시스템에 미치는 영향을 분석하였다. 기초해석 결과, 수직응력이 수평응력보다 우세한 정단층 응력조건에서 전단미끄러짐 가능성이 가장 높은 결과를 보였으며, 단위시간당 주입량을 달리하는 주입량 시나리오 해석에서는 주입량을 단계적으로 증가시켜 주입하는 경우가 공극압의 증가폭이 가장 크고 활동마찰계수를 이용한 전단미끄러짐 가능성 평가 결과에서도 가장 불리한 것으로 평가되었다.

• 한국재난정보학회 논문집
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• 제11권1호
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• pp.23-34
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• 2015

본 연구에서는 충청북도 내 각 지자체를 대상으로 지역별 대설특성을 통한 잠재적 위험요인을 분석하였다. 분석결과, 35년 평균적설량으로 인한 잠재적 위험도는 제천시와 보은군이 가장 높았으며 35년 최대적설량을 통한 잠재적 위험요인에서는 다른 결과가 도출되는 것을 알 수 있었다. 잠재적 위험요인에 대한 지역의 빈도수를 살펴보면 가장 높은 지역은 보은군, 제천시, 괴산군, 영동군, 청주시 순으로 도출되었다. 본 연구는 일반적인 대설특성 뿐만 아니라 잠재적인 위험요인들을 도출하고 그에 대한 위험도를 제시하였다는 점에서 그 의의를 가진다. 본 연구의 결과는 향후 충청북도 각 지자체들의 제설대응체계 및 방안 마련에 기초자료로 활용할 수 있을 것이다.

• 한국지반환경공학회 논문집
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• 제19권10호
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• pp.13-19
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• 2018

2016년 경주지진에 이어 2017년에도 포항지진이 발생하여 우리나라 동남권 지역이 지진의 위협을 받고 있는 실정이다. 특히, 포항지진에서는 연안의 퇴적지반에서 액상화 현상이 발생하여 이에 대한 대책 마련이 크게 중요시되고 있다. 지반 액상화는 지표면 위의 구조물뿐만 아니라 지중의 시설에 대해 직접적인 영향을 줄 수 있기 때문에 발생 가능한 지진에 대한 시설물의 액상화 위험도를 파악하여 이에 대한 대책을 마련할 필요가 있다. 이 연구에서는 최근 국내에서 지진이 발생한 동남권 지역의 전력구를 대상으로 지진 시 액상화 위험도를 평가하였다. 이때, 발생 가능한 지진은 재현주기 1,000년으로 고려하였으며 지진 시 액상화 위험도는 액상화 발생가능성 지수를 통해 검토하였다. 액상화 위험도 분석은 2단계로 진행되었으며 1단계에서는 동남권 전력공동구 설치위치의 지반조사자료를 토대로 액상화 발생 가능성 지수를 산정하여 액상화 위험도를 분석하였다. 이때, 지반 내 증폭현상은 지반종별 지반증폭계수를 통해 고려되었다. 2단계 위험도 분석은 1단계 분석에서 액상화 발생 가능성이 매우 높게 판정된 전력구 주변의 시추공 정보를 바탕으로 지진응답해석을 수행하고 이를 토대로 액상화 발생 가능성 지수를 재산정하여 지진 시 액상화 위험도를 재분석하였다. 이때, 이용된 지반조사자료는 국토지반정보 통합DB센터의 자료이며 지진응답해석에서는 3가지의 실지진 가속도 시간이력곡선을 이용하였다. 연구결과, 국내 지중 시설물에 대한 액상화 위험도 평가를 1단계 광역기반의 액상화 위험도 평가를 수행하고 2단계 평가에서는 1단계 평가에서 위험한 곳으로 평가된 지역에 대해서 지진응답해석을 동반한 위험도 평가를 재수행하는 것이 매우 합리적이고 유효적절한 것으로 나타났다.

• Asian Pacific Journal of Cancer Prevention
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• 제15권7호
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• pp.3071-3074
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• 2014

Background: To investigate the related risk factors of postoperative nosocomial pneumonia (POP) in patients withI-IIIa lung cancer. Methods: Medical records of 511 patients who underwent resection for lung cancer between January 2012 to December 2012 were retrospectively reviewed. Risk factors of postoperative pneumonia were identified and evaluated by univariate and multivariate analyses. Results: The incidence of postoperative pneumonia in these lung cancer patients was 2.9% (15 cases). Compared with 496 patients who had no pneumonia infection after operation, older age (>60), histopathological type of squamous cell carcinoma and longer surgery time (>3h) were significant risk factors by univariate analysis. Other potential risk factors such as alcohol consumption, history of smoking, hypersensitivity, hypertension, diabetes mellitus and so on were not showed such significance in this study. Further, the multivariate analysis revealed that old age (>60 years) (OR 5.813, p=0.018) and histopathological type of squamous cell carcinoma (OR 5.831, p<0.001) were also statistically significant independent risk factors for postoperative pneumonia. Conclusions: This study demonstrated that being old aged (>60 years) and having squamous cell carcinoma histopathological type might be important factors in determining the risk of postoperative pneumonia in lung cancer patients after surgery.

• 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.

• 상하수도학회지
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• 제29권3호
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• pp.381-393
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• 2015

This study is carried out in order to propose a drought risk assessment methodology. This methodology is required to deal with practical questions that a variety of stakeholder often raise in the course of discussions on mitigation measures. With a focus on the socioeconomic aspect of drought, more particularly, residents' hardship from water scarcity, it suggests basic concepts and a system of methods in order to assess hazard, exposure, vulnerability and risk. The case study shows a considerable possibility of the methodology in evaluating potential levels of damages in a certain area, in identifying the boundary of districts where risk is disproportionately concentrated, and also in understanding the underlying risk factors of those districts. The authors think that the proposed methodology is able to offer risk information in terms of socioeconomic damages, and therefore contribute to reducing information gaps that policy-makers are currently encountered with.

• 대한상부위장관⦁헬리코박터학회지
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• 제18권4호
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• pp.225-230
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• 2018

Upper gastrointestinal (GI) bleeding (UGIB) is the most common GI emergency, and it is associated with significant morbidity and mortality. Early identification of low-risk patients suitable for outpatient management has the potential to reduce unnecessary costs, and prompt triage of high-risk patients could allow appropriate intervention and minimize morbidity and mortality. Several risk-scoring systems have been developed to predict the outcomes of UGIB. As each scoring system measures different primary outcome variables, appropriate risk scores must be implemented in clinical practice. The Glasgow-Blatchford score (GBS) should be used to predict the need for interventions such as blood transfusion or endoscopic or surgical treatment. Patients with GBS ${\leq}1$ have a low likelihood of adverse outcomes and can be considered for early discharge. The Rockall score was externally validated and is widely used for prediction of mortality. The recently developed AIMS65 score is easy to calculate and was proposed to predict in-hospital mortality. The Forrest classification is based on endoscopic findings and can be used to stratify patients into high- and low-risk categories in terms of rebleeding and thus is useful in predicting the need for endoscopic hemostasis. Early risk stratification is critical in the management of UGIB and may improve patient outcome and reduce unnecessary health care costs through standardization of care.

• 한국안전학회지
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• 제33권6호
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• pp.77-84
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• 2018

Report documents of industrial and occupational accidents have continuously been accumulated in private and public institutes. Amongst others, information on narrative-texts of accidents such as accident processes and risk factors contained in disaster report documents is gaining the useful value for accident analysis. Despite this increasingly potential value of analysis of text information, scientific and algorithmic text analytics for safety management has not been carried out yet. Thus, this study aims to develop data processing and visualization techniques that provide a systematic and structural view of text information contained in a disaster report document so that safety managers can effectively analyze accident risk factors. To this end, the risk factor map using text mining and self-organizing map is developed. Text mining is firstly used to extract risk keywords from disaster report documents and then, the Self-Organizing Map (SOM) algorithm is conducted to visualize the risk factor map based on the similarity of disaster report documents. As a result, it is expected that fruitful text information buried in a myriad of disaster report documents is analyzed, providing risk factors to safety managers.