• 대한수학회논문집
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• 제35권4호
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• pp.1329-1352
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• 2020

In this paper we consider a class of nonlinear evolution equations on infinite dimensional Banach spaces driven by vector measures. We prove existence and uniqueness of solutions and continuous dependence of solutions on the control measures. Using these results we prove existence of optimal controls for Bolza problems. Based on this result we present necessary conditions of optimality.

• Nuclear Engineering and Technology
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• 제54권4호
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• pp.1245-1252
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• 2022

As regulatory bodies require full implementation of security controls in nuclear power plants (NPPs), security functions for critical digital assets are currently being developed. For the ultimate introduction of security controls, not alternative measures, it is important to understand the relationship between possible cyber threats to NPPs and security controls to prevent them. To address the effectiveness of the security control implementation, this study investigated the types of cyber threats that can be prevented when the security controls are implemented through the mapping of the reorganized security controls in RS-015 to cyber threats on NPPs. Through this work, the cyber threat that each security control can prevent was confirmed, and the effectiveness of several strategies for implementing the security controls were compared. This study will be a useful reference for utilities or researchers who cannot use design basis threat (DBT) directly and be helpful when introducing security controls to NPPs that do not have actual security functions.

• 대한수학회논문집
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• 제28권2호
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• pp.285-295
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• 2013

In this note we present sufficient conditions for the existence of Radon-Nikodym derivatives (RND) of operator valued measures with respect to scalar measures. The RND is characterized by the Bochner integral in the strong operator topology of a strongly measurable operator valued function with respect to a nonnegative finite measure. Using this result we also obtain a characterization of compact sets in the space of operator valued measures. An extension of this result is also given using the theory of Pettis integral. These results have interesting applications in the study of evolution equations on Banach spaces driven by operator valued measures as structural controls.

• Asia pacific journal of information systems
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• 제5권2호
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• pp.79-100
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• 1995

Internal Control(IC) comprises the plan of organization and all of the coordinating methods and measures adopted in a business to safeguard its assets, check the accuracy and reliability of its accounting data, promote operational efficiency and encourage adherence to the prescribed managerial policies. If an organization's IC is not adequate, Accounting Information System (AIS) will be vulnerable to accomplish the organizations successes. Therefore, an effective and efficient IC is essential to its successes. The purpose of this study is to analyze the impact of EDP IC on the perceived usefulness of AIS. Do the general controls indirectively affect to the usefulness of AIS through th application controls? To solve these problems, a research model and a set of hypotheses were established and empirically tested. 60 financial institutions (banks, insurance companies, security companies) agreed to participate in the study. Data were gathered through structured interviews with 60 information systems managers and 537 users of accounting information of each company. Survey forms were designed and collected from financial institutions in Seoul. Information systems' managers of financial institutions responded to questionnaire(1) which consists of a series of 70 questions related to practice and perceived importance. Questionnaire (2) was received from 537 users, who responded to series of 17 questions related to the perceived usefulness. The results of analysis are summarized below. Effects of general controls are more direct on AIS's usefulness than those of application controls. Whereas, indirect effects of application controls are geater than those of general controls. Therefore, the greater the effects of application controls on general controls, the higher the perceived usefulness of AIS. In conclusion, this study supports that the perceived usefulness of AIS is affected by IC which are composed of general controls and application controls. The results of this study has significant implication to financial institution as computer fraud potential increases. Because of global competitions, financial institutions should restructure to IC and AIS in order to take advantage of the technological progress in Information System.

• Tuberculosis and Respiratory Diseases
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• 제79권4호
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• pp.234-240
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• 2016

Transmission of tuberculosis (TB) is a recognized risk to patients and healthcare workers in healthcare settings. The literature review suggests that implementation of combination control measures reduces the risk of TB transmission. Guidelines suggest a three-level hierarchy of controls including administrative, environmental, and respiratory protection. Among environmental controls, installation of ventilation systems is a priority because ventilation reduces the number of infectious particles in the air. Natural ventilation is cost-effective but depends on climatic conditions. Supplemented intervention such as air-cleaning methods including high efficiency particulate air filtration and ultraviolet germicidal irradiation should be considered in areas where adequate ventilation is difficult to achieve. Personal protective equipment including particulate respirators provides additional benefit when administrative and environmental controls cannot assure protection.

• Asian Pacific Journal of Cancer Prevention
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• 제13권6호
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• pp.2481-2484
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• 2012

Aim: The risk factors mostly strongly associated with gastric cancer are gastric bacteria Helicobacter pylori and diet. Using a case-control study among residents in Jinan, we examined the association between the salt taste and gastric cancer according to H. pylori infection, smoking and histological type as well as tumor site. Methods: This population-based case-control study included 207 cases and 410 controls. Data on potential risk factors of gastric cancer were obtained by interview of cases and controls with a questionnaire, salt taste preference was measured for all subjects, and IgG antibodies to H. pylori were applied to assess infection. Risk measures were determined using unconditional logistic regression. Results: The proportions of salt taste at intervals of 1.8-7.2 g/L and ${\geq}7.2$ g/L were significantly higher in cases than controls, with ORs of 1.56 (1.23-3.64) and 2.03 (2.12-4.11), respectively, subjects with high salt intake having an elevated risk for gastric cancer when infected with H. pylori. Significant modification by smoking and tumor site was observed across the different measures of salt intake, the highest salt taste showed higher cancer risk in ever smokers or with non-cardia cancers. Conclusion: Our study supports the view that high intake of sodium is an important dietary risk factor for gastric cancer, with a synergistic effect found between salt and H.pylori and smoking, dependent on the tumor site.

• 한국CDE학회논문집
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• 제21권1호
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• pp.42-50
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• 2016

Traditional tactile controls that include push buttons and rotary switches may cause significant visual and biomechanical distractions if they are located away from the driver's line of sight and hand position, for example, on the central console. Gestural controls, as an alternative to traditional controls, are natural and can reduce visual distractions; however, their types and numbers are limited and have no feedback. To overcome the problems, a driver interface combining gestures and visual feedback with a head-up display has been proposed recently. In this paper, we investigated the effect of this type of interface in terms of driving performance measures. Human-in-the-loop experiments were conducted using a driving simulator with the traditional tactile and the new gesture-based interfaces. The experimental results showed that the new interface caused less visual distractions, better gap control between ego and target vehicles, and better recognition of road conditions comparing to the traditional one.

• Asian Pacific Journal of Cancer Prevention
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• 제16권7호
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• pp.2739-2743
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• 2015

Background: More than 1 million cancer survivors reside in Korea. We here investigated activity limitations of cancer survivors compared to controls without a history of cancer. Materials and Methods: Using the 4th and 5th Korea National Health and Nutrition Examination Survey (2007-2012) data, we identified 1,155 adult cancer survivors. Activity limitations were defined as limitation in activities of daily living, experience of lying in a sickbed, and number of days lying in a sickbed during the last month. Descriptive analysis and multiple logistic regression compared these measures for survivors and controls by sex and age groups. Results: Approximately 29.4% of cancer survivors reported limitation in activities of daily living, 14.6% experienced lying in a sickbed, and 4.3% experienced more than 15 days lying in a sickbed during the last month. After controlling for demographic and health-related factors, cancer survivors were more likely to report activity limitation than controls. The associations were similar across sex and age groups. Conclusions: Cancer survivors have increased activity limitation compared to controls and these limitations persist across sex and age. Targeted interventions and improved management are essential for improving cancer survivor daily life.

• 한국통신학회논문지
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• 제19권5호
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• pp.892-900
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• 1994

ITU-TSS에서는 최근 B-ISDN의 신호 전송을 위하여 service specific connection oriented protocol(SSCOP)을 권고하였다. SSCOP에서는 오류 제어 및 흐름 제어를 위하여 주기적으로 상태 정보를 교환한다. 본 논문에서는 SSCOP를 end-to-end의 경우와 link-by-link인 경우로 나누어 이산 대기 모델로 분석하였다. 메시지의 에러율, 트래픽 부하, 상태 정보의 교환주기 등의 영향을 고려하여 성능 측정값으로써 지연기산, 수신단 버퍼 크기, 그리고 전송 효율의 평균값을 구하고 성능 분석의 결과를 검증하기 위하여 시뮬레이션을 수행하였다.

• 정보보호학회논문지
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• 제29권4호
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• pp.877-884
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• 2019

기술발전에 따라 원자력시설에 사용되는 장비가 아날로그 시스템에서 디지털 시스템으로 변경되는 추세이다. 컴퓨터와 디지털시스템의 비율이 증가함에 따라 원자력시설은 사이버 위협에 노출되었다. 그 결과 사이버보안에 대한 관심이 높아지고 사이버 공격으로부터 시스템을 보호해야 한다는 인식의 변화가 생겼다. 국내 규제기관에서 발행한 KINAC/RS-015는 필수디지털자산에 대해 101가지 사이버보안 통제항목을 제시하였지만 디지털자산의 특성을 고려하지 않은 일반적인 항목이다. 모든 사이버보안 통제항목을 필수디지털자산에 적용하는 것은 많은 작업량과 효율성을 떨어뜨린다. 본 논문에서는 필수디지털자산의 특성을 파악하고 적절한 보안조치항목을 제시함으로써 효과적인 사이버 보안 통제항목 적용을 제안한다.