• Journal of Astronomy and Space Sciences
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• 제34권4호
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• pp.289-302
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• 2017

The key risk analysis technologies for the re-entry of space objects into Earth's atmosphere are divided into four categories: cataloguing and databases of the re-entry of space objects, lifetime and re-entry trajectory predictions, break-up models after re-entry and multiple debris distribution predictions, and ground impact probability models. In this study, we focused on reentry prediction, including orbital lifetime assessments, for space situational awareness systems. Re-entry predictions are very difficult and are affected by various sources of uncertainty. In particular, during uncontrolled re-entry, large spacecraft may break into several pieces of debris, and the surviving fragments can be a significant hazard for persons and properties on the ground. In recent years, specific methods and procedures have been developed to provide clear information for predicting and analyzing the re-entry of space objects and for ground-risk assessments. Representative tools include object reentry survival analysis tool (ORSAT) and debris assessment software (DAS) developed by National Aeronautics and Space Administration (NASA), spacecraft atmospheric re-entry and aerothermal break-up (SCARAB) and debris risk assessment and mitigation analysis (DRAMA) developed by European Space Agency (ESA), and semi-analytic tool for end of life analysis (STELA) developed by Centre National d'Etudes Spatiales (CNES). In this study, various surveys of existing re-entry space objects are reviewed, and an efficient re-entry prediction technique is suggested based on STELA, the life-cycle analysis tool for satellites, and DRAMA, a re-entry analysis tool. To verify the proposed method, the re-entry of the Tiangong-1 Space Lab, which is expected to re-enter Earth's atmosphere shortly, was simulated. Eventually, these results will provide a basis for space situational awareness risk analyses of the re-entry of space objects.

• East Asian mathematical journal
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• 제35권4호
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• pp.387-406
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• 2019

The Korea Foundation for the Advancement of Science and Creativity(KOFAC) developed AlgeoMath, a dynamic geometry software, with support from the Ministry of Education and 17 municipal and provincial education offices. Starting Nov. 7, 2018, AlgeoMath can be used for free by anyone. This study summarizes various discussions on the future direction of math education. The four aspects of the curriculum, textbook, teaching and learning, and assessment were explored on how AlgeoMath could contribute in realizing the future direction of math education. We confirmed that AlgeoMath can faithfully fulfill its role as a tool for changing math education, and we looked at what should be emphasized more and what should be complemented.

• Journal of Ship and Ocean Technology
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• 제4권4호
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• pp.1-18
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• 2000

The paper describes a formalisation of a Design for Safety methodology in an integrated envi-ronment, outlines early developments of a software tool, and presents the results of an appli-cation of the methodology to a case study. The approach adopted attempts link safety per-formance prediction through the utilisation of appropriate technical tools, safety assessment deriving from risk-based methodologies and disparate design activities and issues. Black-board systems have been utilised as the platform in the development of the integrated design environment, allowing safety assessment to become an integral part of the design process. Finally, the case study addresses the application of the developed methodology to three dif-ferent arrangements of a conventional passenger Ro-Ro vessel, with the aim to demonstrate the validity of the process and methodology adopted. The findings are presented and dis-cussed, and recommendations given for the way forward.

• 대한치위생과학회지
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• 제6권2호
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• pp.79-89
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• 2023

연구 배경 및 목적: 치매 유병률은 매년 증가하는 추세를 보이고 있으며, 치매와 구강 건강의 관련성에 대한 선행 연구들이 계속해서 진행되고 있다. 임상 치과위생사는 적절한 치과 의료서비스 제공을 위한 전문적인 역량이 필요하며, 치과위생사의 지식 수준을 객관적으로 측정할 수 있는 도구 개발이 필요하다. 이에 임상 치과위생사의 치매 환자 치과 진료 시 고려사항에 대한 지식 측정도구를 개발하고자 하였다. 연구 방법: 문헌 고찰을 바탕으로 예비문항을 구성하여 전문가 검증, 예비조사, 본조사를 진행하였다. 본조사는 임상 경력이 1년 이상인 치과위생사 220명을 대상으로 설문조사를 시행하였다. 수집된 자료를 바탕으로 타당도 분석, 신뢰도 분석을 진행하여 최종 문항을 선정하였고, 선정된 문항별 정답률을 확인하였다. 연구 결과: 수집된 자료 분석 결과, 총 40개의 예비문항 중 18문항이 삭제되어 총 6개 요인, 22문항이 선정되었으며, 선정된 문항의 Cronbach's α값은 0.791로 나타났다. 하위 항목 별 문항 수는 '치매 환자의 치과 진료 시 주의사항' 5문항, 치매 환자의 약물 부작용' 4문항, 치매 환자의 구강 관리 방법' 4문항, '치매 환자와의 의사소통' 4문항, '치매 환자의 심리적 반응' 3문항, '치매 환자 안내' 2문항으로 구성하였다. 정답률이 가장 높았던 문항은 '치매 환자 안내' 항목의 2번 문항이 98.6%, 정답률이 가장 낮았던 문항은 '치매 환자의 심리적 반응' 항목의 2번 문항이 5.9%로 나타났다. 결론: 본 연구를 통해 타당도와 신뢰도가 검증된 도구는 향후 임상 치과위생사와 치매 관련 후속 연구의 기반으로 활용할 수 있으며, 보수교육, 교육 프로그램 개발, 의료기관 내 업무 지침 개발의 기초 자료로 기여하고자 한다.

• 방사선산업학회지
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• 제17권3호
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• pp.265-273
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• 2023

To effectively and safely manage the radiation exposure to nuclear power plant (NPP) workers in accidents, major overseas NPP operators such as the United States, Germany, and France have developed and applied realistic 3D model radiation dose assessment software for workers. Continuous research and development have recently been conducted, such as performing NPP accident management using 3D-VR based on As Low As Reasonably Achievable (ALARA) planning tool. In line with this global trend, it is also required to secure technology to manage radiation exposure of workers in Korea efficiently. Therefore, in this paper, it is described the application method and assessment results of radiation exposure scenarios for workers in response to accidents assessment technology, which is one of the fundamental technologies for constructing a realistic platform to be utilized for radiation exposure prediction, diagnosis, management, and training simulations following accidents. First, the post-accident sampling after the Loss of Coolant Accident(LOCA) was selected as the accident and response scenario, and the assessment area related to this work was established. Subsequently, the structures within the assessment area were modeled using MCNP, and the radiation source of the equipment was inputted. Based on this, the radiation dose distribution in the assessment area was assessed. Afterward, considering the three principles of external radiation protection (time, distance, and shielding) detailed work scenarios were developed by varying the number of workers, the presence or absence of a shield, and the location of the shield. The radiation exposure doses received by workers were compared and analyzed for each scenario, and based on the results, the optimal accident response scenario was derived. The results of this study plan to be utilized as a fundamental technology to ensure the safety of workers through simulations targeting various reactor types and accident response scenarios in the future. Furthermore, it is expected to secure the possibility of developing a data-based ALARA decision support system for predicting radiation exposure dose at NPP sites.

• 한국압력기기공학회 논문집
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• 제10권1호
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• pp.75-81
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• 2014

A simulation of eddy current testing has been utilized for predicting the signal characteristics to the various defects and developing the probes. Especially, CIVA which is a simulation tool dedicated to nondestructive testing has a good accuracy and speed, and provides a three-dimensional graphical user interface for improved visualization and familiar data displays consistent with NDE technique. Although internal validations have been performed by the CIVA software development specialists, an independent validation study is necessary for the accuracy assessment of the software prior to practical use. For this purpose, in this study, eddy current testing signals of ASME FBH calibration standard tube for bobbin probe were simulated using CIVA and the results were compared to the experimental inspected signals based on the relationship between each flaw signal in terms of amplitude and phase, and the shape of the Lissajous curve. And then we verified the accuracy of the simulated signals and the possible range for simulation. Overall, there is a good qualitative agreement between the CIVA simulated and experimental results in the absolute and differential modes at the two inspection frequencies.

• 반도체디스플레이기술학회지
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• 제16권3호
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• pp.71-77
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• 2017

As the automobile industry has shifted to software, the Automotive SPICE standard has been established to ensure efficient product development process and quality. In the assessment model, the HIS Scope is the minimum standard for small and medium automotive electric companies to meet OEM requirements. However, in order to achieve the HIS Scope, the output of each process stage that meets the verification criteria of Automotive SPICE must be created. In particular, the test phase takes a lot of resources, which is a big burden for small and medium-sized companies. In this paper, we propose a methodology for creating test cases of software integration test phase based on UML sequence diagram, which is a software design phase of Automotive SPICE HIS Scope, by applying behavior model based testing method. We also propose a tool chain for automating the creation process. This will reduce the resources required to create a test case.

• 디지털융복합연구
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• 제10권3호
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• pp.121-126
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• 2012

본 논문에서는 의사의 진단 없이 개인의 건강관련 정보만을 이용하여 암 발생 위험도를 예측할 수 있는 소프트웨어 시스템(CARA)의 활용도를 극대화 할 수 있는 방안을 제안한다. 이를 위하여 CARA에 대한 전반적인 설명을 하고, 전국적인 인터넷 망을 활용하는 CARA 활용도 극대화 방안을 설명한다. CARA를 사용하면 암 발생 위험도가 높은 사람을 (병원에서의 진단 이전에)미리 선별할 수 있어 암으로 인한 피해를 줄일 수 있다. 또한 CARA는 개인정보와 암에 관련된 상관관계를 실험적으로 밝힐 수 있는 도구로도 사용될 수 있어 의학연구에도 도움을 줄 수 있다. CARA는 기존의 유사 소프트웨어와 달리 30종의 암을 동시에 고려하는 새로운 시스템으로 암의 조기발견에 매우 효과적으로 활용될 수 있다.

• Structural Engineering and Mechanics
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• 제46권2호
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• pp.213-229
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• 2013

Although performance based assessment procedures are mainly developed for reinforced concrete and steel buildings, URM (Unreinforced Masonry) buildings occupy significant portion of buildings in earthquake prone areas of the world as well as in IRAN. Variability of material properties, non-engineered nature of the construction and difficulties in structural analysis of masonry walls make analysis of URM buildings challenging. Despite sophisticated finite element models satisfy the modeling requirements, extensive experimental data for definition of material behavior and high computational resources are needed. Recently, nonlinear equivalent frame models which are developed assigning lumped plastic hinges to isotropic and homogenous equivalent frame elements are used for nonlinear modeling of URM buildings. The equivalent frame models are not novel for the analysis of masonry structures, but the actual potentialities have not yet been completely studied, particularly for non-linear applications. In the present paper an effective tool for the non-linear static analysis of 2D masonry walls is presented. The work presented in this study is about performance assessment of unreinforced brick masonry buildings through nonlinear equivalent frame modeling technique. Reliability of the proposed models is tested with a reversed cyclic experiment conducted on a full scale, two-story URM building at the University of Pavia. The pushover curves were found to provide good agreement with the experimental backbone curves. Furthermore, the results of analysis show that EFM (Equivalent Frame Model) with Dolce RO (rigid offset zone) and shell element have good agreement with finite element software and experimental results.

• Nuclear Engineering and Technology
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• 제55권1호
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• pp.119-130
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• 2023

Among the various elements of probabilistic safety assessment (PSA), human failure events (HFEs) and their dependencies are major contributors to the quantification of risk of a nuclear power plant. Currently, the dependency among HFEs is reflected using a post-processing method in PSA, wherein several drawbacks, such as limited propagation of minimal cutsets through the fault tree and improper truncation of minimal cutsets exist. In this paper, we propose a method to model the HFE dependency directly in a fault tree using the if-then-else logic. The proposed method proved to be equivalent to the conventional post-processing method while addressing the drawbacks of the latter. We also developed a software tool to facilitate the implementation of the proposed method considering the need for modeling the dependency between multiple HFEs. We applied the proposed method to a specific case to demonstrate the drawbacks of the conventional post-processing method and the advantages of the proposed method. When applied appropriately under specific conditions, the direct fault-tree modeling of HFE dependency enhances the accuracy of the risk quantification and facilitates the analysis of minimal cutsets.