• Journal of the Korean Data and Information Science Society
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• 제27권4호
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• pp.1083-1090
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• 2016

In clinical studies, different types of outcomes (e.g. repeated measures data and time-to-event data) for the same subject tend to be observed, and these data can be correlated. For example, a response variable of interest can be measured repeatedly over time on the same subject and at the same time, an event time representing a terminating event is also obtained. Joint modelling using a shared random effect is useful for analyzing these data. Inferences based on marginal likelihood may involve the evaluation of analytically intractable integrations over the random-effect distributions. In this paper we propose a joint HGLM approach for analyzing such outcomes using the HGLM (hierarchical generalized linear model) method based on h-likelihood (i.e. hierarchical likelihood), which avoids these integration itself. The proposed method has been demonstrated using various numerical studies.

• International Journal of Reliability and Applications
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• 제2권1호
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• pp.27-36
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• 2001

This Paper proposes a new methodology for assessing the reliability of an accident management, which Is based on the reliability physics and the scheme to generate dynamic event tree. The methodology consists of 3 main steps: screening; uncertainty propagation; and probability estimation. Sensitivity analysis is used for screening the variables of significance. Latin Hypercube sampling technique and MAAP code are used for uncertainty propagation, and the dynamic event tree generation method is used for the estimation of non-success probability of implementing an accident management strategy. This approach is applied in assessing the non-success probability of implementing a cavity flooding strategy, which is to supply water into the reactor cavity using emergency fire systems during the sequence of station blackout at the reference plant.

• 한국컴퓨터정보학회논문지
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• 제24권5호
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• pp.59-66
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• 2019

According to the KT telecommunication statistics, people stayed inside their houses on an average of 11.9 hours a day. As well as, according to NSC statistics in the united states, people regardless of age are injured for a variety of reasons in their houses. For purposes of this research, we have investigated an abnormal event detection algorithm to classify infrequently occurring behaviors as accidents, health emergencies, etc. in their daily lives. We propose a fusion method that combines three classification algorithms with vision pattern, audio pattern, and activity pattern to detect unusual user events. The vision pattern algorithm identifies people and objects based on video data collected through home CCTV. The audio and activity pattern algorithms classify user audio and activity behaviors using the data collected from built-in sensors on their smartphones in their houses. We evaluated the proposed individual pattern algorithm and fusion method based on multiple scenarios.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제16권12호
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• pp.1269-1273
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• 2010

일반적으로 사용자는 휴대폰에서 촬영한 개인용 사진 컬렉션에 대하여 이벤트 기준으로 관리 및 접근하는 것을 선호한다. 본 논문에서는 휴대폰상의 개인용 사진 컬렉션에 대하여 계산 량이 적고 정확도가 높으며 증감적인 클러스터링을 지원하는 이벤트 클러스터링 알고리즘을 제안하였다. 제안한 방법은 실제 샘플 사진들을 수집하여 이벤트 내의 사진들의 시간 경과 치에 대한 통계적 분석을 통하여 이벤트 경계 구간을 결정하였으며, 시간 정보만으로 분할이 모호한 구간에서는 위치 정보와 시각 정보를 사용하여 보완하였다. 본 논문에서는 제안한 방법에 대하여 실험 및 검증을 수행하였으며, 기존의 일반적인 클러스터링 방법에 비하여 높은 성능을 나타내는 것을 확인하였다.

• 대한인간공학회지
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• 제22권1호
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• pp.81-94
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• 2003

The British railway safety research group has developed a risk assessment model for the railway infrastructure and major railway accidents. The major hazardous factors of the railway infrastructure were identified and classified in the model. The frequency rates of critical top events were predicted by the fault tree analysis method using failure data of the railway system components and ratings of railway maintenance experts, The consequences of critical top events were predicted by the event tree analysis method. They classified the Joss of accident due to railway system into personal. commercial and environmental damages. They also classified 110 hazardous event due to railway system into three categories. train accident. movement accident and non-movement accident. The risk assessment model of the British railway system has been designed to take full account of both the high frequency low consequence type events (events occurring routinely for which there is significant quantity of recorded data) and the low frequency high consequence events (events occurring rarely for which there is little recorded data). The results for each hazardous event were presented in terms of the frequency of occurrence (number of events/year) and the risk (number of equivalent fatalities per year).

• International Journal of Contents
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• 제16권1호
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• pp.25-33
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• 2020

We develop a simulation method that affords very high variability of virtual pedagogical situations involving many independent plans, still achieves authoring (or implementation) scalability. While each individual plan would be coherently drawn up by an agent for its respective goal, those independently-made plans might be coincidentally intertwined in their execution. The inevitable non-determinism involved in this multi-event plan encompassing pre-planned and unforeseen events is resolved by (multi-phase) dynamic planning and articulated sequencing of events in contrast to static planning and monolithic authoring in conventional narrative systems. Connections between events are dictated by their associated rules and their actual connections are dynamically determined in execution time by current conditions of background-world. This unified connection scheme across pre-planned and unforeseen events allows a multi-plan, multi-agent situation to be coherently planned and executed in a global scale. To further the variability of a situation, the inter-event coupling is made in a fine level of action along with a limited episteme of each agent involved. We confirm analytically the viability of our approach with respect to the situation variability and authoring scalability, and demonstrate its practicality with an implementation of a composite situation.

• 대한전기학회논문지:전력기술부문A
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• 제53권10호
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• pp.565-572
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• 2004

This paper proposes an expert system which can enhance the accuracy of real-time bus reconfiguration strategy by adopting local minimum tree search method and minimize the spreading effect of the fault by considering totally the operating condition when a main transformer fault occurs in the automated substation. The local minimum tree search method to expand the best-first search method. This method has an advantage which can improve the performance of solution within the limits of the real-time condition. The inference strategy proposed expert system consists of two stages. The first stage determines the switching candidate set by searching possible switching candidates starting from the main transformer or busbar related to the event. And, second stage determines the rational real-time bus reconfiguration strategy based on heuristic rules for the obtained switching candidate set. Also, this paper studies the generalized distribution substation modelling using graph theory and a substation database is designed based on the study result. The inference engine of the expert system and the substation database is implemented in MFC function of Visual C++. Finally, the performance and effectiveness of the proposed expert system is verified by comparing the best-first search solution and local minimum tree search solution based on diversity event simulations for typical distribution substation.

• 정보처리학회논문지D
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• 제8D권5호
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• pp.513-522
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• 2001

능동 데이터베이스는 미리 정의된 규칙(rule)에 의해 규칙에 대응하는 사건이 발생하면 자동으로 트리거나 되어 조건을 평가하고 조치를 수행한다. 이러한 능동 규칙은 연속적으로 서로 다른 트리거 할 수 있고 그로 인해 종료하지 못하고 무한한 순환적 동작을 반복할 가능성이 있다. 따라서 이 논문에서는 규칙집합의 종료를 보장하는 종료 분석방법을 제안한다. 여기서 제안한 방법은 정확한 종료 분석을 위해 복합사건의 규칙과 규칙 실행시간을 고려한다. 아울러 규칙간에 형성되는 비활성과 관계를 이용하여 그래프를 기존의 트리거그래프와 결합시킴으로서 규칙 종료의 복잡성 개선과 분석 결과의 정확성을 향상시킨다.

• Nuclear Engineering and Technology
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• 제50권8호
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• pp.1234-1245
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• 2018

The risk of multi-unit nuclear power plants (NPPs) at a site has received considerable critical attention recently. However, current probabilistic safety assessment (PSA) procedures and computer code do not support multi-unit PSA because the traditional PSA structure is mostly used for the quantification of single-unit NPP risk. In this study, the main purpose is to develop a multi-unit Level 2 PSA method and apply it to full-power operating six-unit OPR1000. Multi-unit Level 2 PSA method consists of three steps: (1) development of single-unit Level 2 PSA; (2) extracting the mapping data from plant damage state to source term category; and (3) combining multi-unit Level 1 PSA results and mapping fractions. By applying developed multi-unit Level 2 PSA method into six-unit OPR1000, site containment failure probabilities in case of loss of ultimate heat sink, loss of off-site power, tsunami, and seismic event were quantified.

• 한국지진공학회논문집
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• 제2권4호
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• pp.41-52
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• 1998

한반도 동남부에 위치하고 있는 동래단층은 단일 불연속면 단층이 아니라 수많은 소단층을 포함하는 단층대의 형태를 보여준다. 동래단층의 고응력을 해석하기 위하여 부산시 금정구에서 울산시에 이르는 단층 주변의 노두에서 329개의 소단층 자료를 측정하였다 먼저 수집된 솬층 자료의 기하학적인 특징을 살펴보면 주향은 NE계열(N10E, N30E, N70E) 이 우세하며 경사의 경우는 65。 이상의 곡각의 단층이 우세하게 분포한다. 그리고 선주각의 경우는 30。이하가 전체의 절반 이상을 차지한다. 동래단층의 고응력을 해석하기 위해서 수집된 자료를 Angelier의 집적연산 방법과 Choi의 방법을 병행하여 실시하였다 그 결과 동래단측 지역에서 확인된 지구조 사건은 (1) NNE-SSW 압축응력 및 ESE-WNW 인장응력 (사건 1) (2) NNE-SSW 인장응력 (사건II)(3) ESE-WNW 인장응력 (사건III) (4) ENE-WSW 압축응력 및 NNW-SSE 인자응력(사건V) 이다. 이들 지구조 사건에 따른 동래단층 운동을 살펴보면 먼저 사건 I에 의해서 동래단층 지역에 우수감가의 NS주향 좌수 감각의 ENE-WSW 가지는 주향이동성 단층들이 형성되었고 이후 사건 II, III에의해서 정단층성 단층들이 발달되고 사건 IV에 의해서 NNE 주향의 동래단층이 우수 주향이동운동으로 길게 연장 발달한 것으로 추정된다.