• Nuclear Engineering and Technology
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• 제52권4호
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• pp.764-775
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• 2020

Periodic safety reviews (PSRs) are conducted on operating nuclear power plants (NPPs) and have been mandated also for research reactors in Korea, in response to the Fukushima accident. One safety review tool, the probabilistic safety assessment (PSA), aims to identify weaknesses in the design and operation of the research reactor, and to evaluate and compare possible safety improvements. However, the PSA for research reactors is difficult due to scarce data availability. An important element in the analysis of research reactors is the reactor protection system (RPS), with its functionality and importance. In this view, we consider that of the AGN-201K, a zero-power reactor without forced decay heat removal systems, to demonstrate a risk-informed safety improvement study. By incorporating risk- and safety-significance importance measures, and sensitivity and uncertainty analyses, the proposed method identifies critical components in the RPS reliability model, systematically proposes potential safety improvements and ranks them to assist in the decision-making process.

• 대한안전경영과학회지
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• 제16권4호
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• pp.101-111
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• 2014

Aviation safety is increasingly important to secure the safety of the Republic of Korea Air Force (ROKAF). A critical activity for enhancing aviation safety is to analyze an accident throughly and to identify causes that can explain it reasonably. The results of such a systematic accident investigation can be effectively used for improving information displays, task procedures, and training systems as well as for reorganizing team structure and communication control system. However, the current practice of analyzing aviation accidents in ROKAF is too superficial and simple to diagnose them systematically. Additionally, the current practice does not give a full consideration to human factors that have been identified as main causes of most of the aviation accidents. With this issue in mind, this study aims to suggest a new approach to analyzing aviation accidents related to human factors.The proposed method is developed on the basis of several models and frameworks about system safety, human error, and human-system interaction. Its application to forty-two human factors-related accidents, which have occurred in ROKAF during the last ten years, showed that the proposed method could be a useful tool for analyzing aviation accidents caused by human factors.

• Nuclear Engineering and Technology
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• 제48권1호
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• pp.153-163
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• 2016

Environments in nuclear power plants (NPPs) are changing as the design of instrumentation and control systems for NPPs is rapidly moving toward fully digital instrumentation and control, and modern computer techniques are gradually introduced into main control rooms (MCRs). Within the context of these environmental changes, the level of performance of operators in a digital MCR is a major concern. Situation awareness (SA), which is used within human factors research to explain to what extent operators of safety-critical systems know what is transpiring in the system and the environment, is considered a prerequisite factor to guarantee the safe operation of NPPs. However, the safe operation of NPPs can be guaranteed through a team effort. In this regard, the operating team's SA in a conventional and digital MCR should be measured in order to assess whether the new design features implemented in a digital MCR affect this parameter. This paper explains the team SA measurement method used in this study and the results of applying this measurement method to operating teams in different MCR environments. The paper also discusses several empirical lessons learned from the results.

• Nuclear Engineering and Technology
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• 제50권4호
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• pp.532-541
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• 2018

Decision support systems are a key focus of research on developing control rooms to aid operators in making reliable decisions and reducing incidents caused by human errors. For this purpose, models of complex systems can be developed to diagnose causes or consequences for specific alarms. Models applied in safety systems of complex and safety-critical systems require rigorous and reliable model building and testing. Multilevel flow modeling is a qualitative and discrete method for diagnosing faults and has previously only been validated by subjective and qualitative means. To ensure reliability during operation, this work aims to synthesize a procedure to measure model performance according to diagnostic requirements. A simple procedure is proposed for validating and evaluating the concept of multilevel flow modeling. For this purpose, expert statements, dynamic process simulations, and pilot plant experiments are used for validation of simple multilevel flow modeling models of a hydrocyclone unit for oil removal from produced water.

• Toxicological Research
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• 제32권1호
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• pp.5-8
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• 2016

Risk assessment is the process of quantifying the probability of a harmful effect to individuals or populations from human activities. Mechanistic approaches to risk assessment have been generally referred to as systems toxicology. Systems toxicology makes use of advanced analytical and computational tools to integrate classical toxicology and quantitative analysis of large networks of molecular and functional changes occurring across multiple levels of biological organization. Three presentations including two case studies involving both in vitro and in vivo approaches described the current state of systems toxicology and the potential for its future application in chemical risk assessment.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권5호
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• pp.1484-1502
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• 2023

The medical sector actively changes and implements innovative features in response to technical development and revolutions. Many of the most crucial elements in IoT-connected health services are safeguarding critical patient records from prospective attackers. As a result, BlockChain (BC) is gaining traction in the business sector owing to its large implementations. As a result, BC can efficiently handle everyday life activities as a distributed and decentralized technology. Compared to other industries, the medical sector is one of the most prominent areas where the BC network might be valuable. It generates a wide range of possibilities and probabilities in existing medical institutions. So, throughout this study, we address BC technology's widespread application and influence in modern medical systems, focusing on the critical requirements for such systems, such as trustworthiness, security, and safety. Furthermore, we built the shared ledger for blockchain-based healthcare providers for patient information, contractual between several other parties. The study's findings demonstrate the usefulness of BC technology in IoHT for keeping patient health data. The BDSA-IoHT eliminates 2.01 seconds of service delay and 1.9 seconds of processing time, enhancing efficiency by nearly 30%.

• 한국정보전자통신기술학회논문지
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• 제4권1호
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• pp.23-31
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• 2011

본 논문은 차세대 자동차 지능형 통합 스마트 모니터 시스템을 제작하였다. 차량의 계기판 장치는 많은 방해 요소를 감소시키며, 운전자들에게 영향을 주지 않고 도로에 집중할 수 있도록 하는 것이 필수적이다. 위험 경보는 시각적인 디스플레이와 함께 유용하게 사용되지만 기존의 방식은 문제가 있다. 차량 안전 시스템의 최적화는 위험을 알리는 각종 경보보다 더 필수적인 것은 운전자가 도로에 집중할 수 있는 시각적인 장치가 요구된다. 지능형 통합 스마트 모니터 시스템은 자동차에서 가장 많이 보는 정보인 자동차 속도, 엔진 회전속도, 연료, 엔진 온도, 연료 게이지, 회전표시등과 각종 경보 표시등 기본 정보를 모아서 운전자에게 제공한다. 본 논문에서 설계한 지능형 통합 스마트 모니터 시스템은 박막 트랜지스터 액정 표시 장치, 액정 표시 장치배경 조명 발광다이오드, 평면 미러, 특수 제작된 렌즈 및 구동회로로 구성되어 있으며, 운전자 안전성을 고려한 차세대 지능형 자동차 통합스마트 모니터 시스템을 제작, 분석하였다.

• 한국정보통신학회논문지
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• 제25권3호
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• pp.368-376
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• 2021

최근 딥러닝 기술이 발전함에 따라 자율 사물 기술이 주목받으면서 드론이나 자율주행차 같은 임베디드 시스템에서 DNN을 많이 활용하고 있다. 클라우드에 의지하지 않고 높은 인식 정확도를 위해서 큰 규모의 연산이 가능하고 다수의 DNN을 처리할 수 있는 임베디드 시스템들이 출시되고 있다. 이러한 시스템 내부에는 다양한 수준의 우선순위를 갖는 DNN들이 존재한다. 자율주행차의 안전 필수에 관련된 DNN들은 가장 높은 우선순위를 갖고 이들은 반드시 최우선적으로 처리되어야 한다. 본 논문에서는 다수의 DNN이 동시에 실행될 때 우선순위를 고려해서 DNN을 스케줄링하는 프레임워크를 제안한다. 낮은 우선순위의 DNN이 먼저 실행되고 있어도 높은 우선순위의 DNN이 이를 선점할 수 있어 자율주행차의 안전 필수 응용의 빠른 응답 특성을 보장한다. 실험을 통하여 확인한 결과 실제 상용보드에서 최대 76.6% 성능이 향상되었다.

• 항공우주시스템공학회지
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• 제18권2호
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• pp.12-20
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• 2024

초소형 위성체의 태생적 공간 제약으로 탑재 전장품은 발사진동환경 하 구조건전성 확보를 위한 보강설계 적용에 한계가 존재하며, 피로파괴에 취약한 고집적 소자의 실장으로 고신뢰도의 평가기법이 요구된다. 종래 전장품 구조건전성 평가를 위해 Steinberg 피로파괴 이론이 적용되고 있으나 최근 연구들에서 이론적 한계점들이 보고되고 있다. 본 논문에서는 상기 이론의 한계점을 극복한 임계변형률 이론기반 방법론을 적용하여 초소형 SAR 군집위성 S-STEP(Small SAR Technology Experimental Project)의 X대역 SAR 탑재체 구성품 중 DCU(Digital Control Unit)를 설계하였다. 설계 유효성 검증을 위해 단순화된 모델링 기법을 기반으로 모드 해석, 랜덤 해석을 수행하였다. 적용한 방법론을 기반으로 해석 결과분석 및 안전여유 도출과 발사진동환경시험 전후 기능시험을 통해 최종적으로 전장품의 구조건전성이 확보됨을 입증하였다.

• Safety and Health at Work
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• 제6권2호
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• pp.146-150
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• 2015

Occupational health and safety (OHS) is a broad field of professional practice, which involves specialists from different disciplines including but not limited to engineers, occupational health physicians, physical and biological scientists, economists, and statisticians. The preventive systems required to ensure workers are protected from injuries and illnesses dwell heavily on engineers; however, the extent to which the engineer can go regarding planning and implementing preventive measures is dependent on specific legal requirements, leadership commitment from the company, organization, and nation. The objective of this paper is to identify the areas of opportunities for improvements in OHS management in Ghana with regard to the nation's legal requirements, commitment of the Ghana government, and Ghanaian leadership as well as appropriate structuring of Ghanaian institutions responsible for monitoring and managing OHS in Ghana. This paper identified Ghana's fragmented legal requirements concerning OHS, which are under different jurisdictions with unclear responsibilities and accountabilities. The paper also highlights the training needs of Ghanaian academic institutions regarding OHS. Among other recommendations made including structuring of Ghanaian institutions to manage OHS in line with the ILO-OSH 2001, this paper aligns the recommendations with the articles and elements of International Labour Organization convention number 155 and OHSAS 18001 elements.