• 치위생과학회지
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• 제17권5호
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• pp.383-397
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• 2017

We attempted to develop a problem-based learning (PBL) module for integrated education in dental hygiene with the aim of helping students gain clinical competencies necessary for dental hygienist work. To develop the PBL Module for Clinical Dentistry in Dental Hygiene course, the researchers identified literature related to not only educational technology, but also medical science, nursing, dentistry, and dental hygiene. During the design phase of the PBL module, problem scenarios and a plan for the teaching and learning process were developed. Developing problem scenarios involved describing a problematic situation and three questions related with that situation. To cultivate competencies required in dental clinics, each question was related to the diagnosis of a dental disease, dental treatment, and dental hygiene procedures for care. Teaching-learning process plan included the designs of operating environment, operational strategies, learning resources, facilitation of problem-solving process, and evaluation. It is necessary to evaluate the PBL module for integrated education in dental hygiene to confirm its effectiveness.

• 한국해양공학회지
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• 제27권1호
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• pp.24-30
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• 2013

The Korea Navy has been making constant efforts to apply M&S (modeling and simulation) to naval ship development, and the generalization of M&S for ship development is a trend. M&S for ship design is used for the V&V (verification and validation) of its design and operation, including design verification and ergonomic design that considers the crew using the Naval Ship Product Model. In addition, many parts of this M&S are repeatedly accomplished regardless of the kinds of ships. This study aims to standardize M&S, which repeatedly applies similar verifications for operation scenarios. A congestion assessment simulation for the major spaces of ships was the subject of the standardization based on the leading research results of various researchers, and a simulation automation solution was suggested. An information model using XML was proposed through the simulation automation concept, and a prototype system based on it was implemented. The usability was shown through a case study that verified the operability performance of the crew messroom.

• 전기학회논문지
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• 제63권10호
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• pp.1393-1401
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• 2014

In this paper the operational characteristics of stand-alone microgrid was analyzed using RTDS simulation models. The accuracy of developed simulation models were verified by comparing with the analysis results using the PSCAD/EMTDC simulation models. The proper scenarios and operation algorithms were developed and analyzed in accordance with various situations that can occur in the actual system, so as to establish operation scheme for the stand-alone microgrid system. The developed simulation models can be effectively utilized to design a newly installed stand-alone microgrid and to develop various operation scenarios for stand-alone microgrid. And these models can be applied for analyzing the transient phenomena due to system fault so that system protection can be properly designed.

• 산업경영시스템학회지
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• 제45권4호
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• pp.8-20
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• 2022

The paint removal of fighter jets is just as important as the painting, because perfect paint removal ensures the quality of the exterior painting on the aircraft. However, the current conditions for paint removal work of the ROKAF's are poor. It is identified that the painting process currently implemented by the ROKAF is not only exposed to harmful compounds such as harmful dust and hexavalent chromium, but also consumes a lot of water. Thus, the introduction of advanced facility is considered. This study compares the fighter jets painting removal process currently applied by the Korean Air Force with the improved laser coating removal process of the US Air Force, and conducts an incremental analysis to perform economic analysis for the introduction of advanced facility. Four scenarios were envisioned on the premise of an increase in the number of fighters in the future, incremental analysis shows that laser coating removal method is advantageous in all scenarios. In addition, it is recommended that paint removal cycle keeps the current 12-year and the outsourcing amount to civilian depot is reduced.

• Nuclear Engineering and Technology
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• 제56권4호
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• pp.1254-1266
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• 2024

This study investigates the application of supercritical carbon dioxide (S-CO₂) direct-cycle micro modular reactors (MMRs) in primary frequency control (PFC), which is a scenario characterized by significant load fluctuations that has received less attention compared to secondary load-following. Using a modified GAMMA + code and a deep neural network-based turbomachinery off-design model, the authors conducted an analysis to assess the behavior of the reactor core and fluid system under different PFC scenarios. The results indicate that the acceptable range for sudden relative electricity output (REO) fluctuations is approximately 20%p which aligns with the performance of combined-cycle gas turbines (CCGTs) and open-cycle gas turbines (OCGTs). In S-CO₂ direct-cycle MMRs, the control of the core operates passively within the operational range by managing coolant density through inventory control. However, when PFC exceeds 35%p, system control failure is observed, suggesting the need for improved control strategies. These findings affirm the potential of S-CO₂ direct-cycle MMRs in PFC operations, representing an advancement in the management of grid fluctuations while ensuring reliable and carbon-free power generation.

• 한국재난정보학회 논문집
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• 제19권2호
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• pp.411-420
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• 2023

연구목적: 수소충전소의 위험성 평가의 한계를 보완하고자 운영중 발생 가능한 사고에 대한 안전성 및 사업연속성을 강화하기 위한 방안으로 기업재해경감활동을 적용을 제안한다. 연구방법: 수소충전소 설치 및 운영의 시간 흐름에 따라 위험을 구분하고, 핵심업무를 식별, 위험시나리오를 도출하여 이를 분석, 평가, 처리하는 과정을 통해 위험을 경감, 제거,전가, 수용할 수 있는 기업재해경감활동의 일부적용을 탐구해 보았다. 연구결과:수소충전소 설치전 단계에 시행하고 있는 위험평가는 기존의 연구 결과가 적절히 적용되고 있다. 그러나 운영단계에서 발생 가능한 위험에 대해서는 한계가 있어 몇 가지 예시 시나리오를 가지고 기업재해경감활동을 적용해 보니 안전성과 사업연속성 강화 방안으로 적용이 가능하다는 결과를 도출하였다. 결론:현재 시행중인 수소충전소 위험성평가는 모두 적절하게 활용되고 있다. 그러나 운영단계에서 발생 가능한 위험에 대한 평가와 대응방안으로 다양한 위험시나리오를 적용하는 기업재해 경감활동을 제안한다.

• International Journal of Aeronautical and Space Sciences
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• 제17권3호
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• pp.391-400
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• 2016

In satellite operations, stable maneuvering of a satellite's onboard antenna to prevent undesirable vibrations to the satellite body is required for high-quality high-resolution images. For this reason, the onboard antenna's angular rate is typically minimized while still satisfying the system requirement that limits the speed of the onboard antenna. In this study, a simple yet effective method, called the ground station searching method, is proposed to reduce the angular rate of a satellite's onboard antenna. The performance of the proposed method is tested using real flight data from the KOMPSAT-3 satellite. Approximately 83% of arbitrarily selected real flight scenarios from 66 test cases show reductions in the onboard antenna's azimuth angular rates. Additionally, reliable solutions were consistently obtained within a reasonably acceptable computation time while generating an onboard antenna tracking profile. The obtained results indicate that the proposed method can be used in real satellite operations and can reduce the operational loads on a ground operator. Although the current work only considers the KOMPSAT-3 satellite as a test case, the proposed method can be easily modified and applied to other satellites that have similar operational characteristics.

• 한국통신학회논문지
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• 제32권5A호
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• pp.441-450
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• 2007

본 논문에서는 위성망 자원할당 및 분석 툴(SNRAT : Satellite Network Resource Allocation & Analysis Tool)을 활용하여 위성통신체계에 대한 링크성능 분석결과를 제시하였으며, 모의위성망을 구성하여 성능분석 툴로 예측한 링크 성능을 검증하였다. 통신위성은 지상장비와 달리 정지궤도에 발사하여 궤도 내 운용을 시작하면, 더 이상 성능의 수정이나 수리가 불가능하고, 운용 가능한 수명이 제한되어 있기 때문에 적기에 배치하여 운용하는 것이 매우 중요하다. 따라서, 위성 발사 전 위성망 자원할당 및 분석 툴을 이용하여 통신품질, 지원용량 및 항재밍 성능 등을 예측하고, 모의위성망을 구축하여 지상단말과 망제어기와 같은 지상장비 및 중계기 규격의 적합성을 증명하였으며, 여러 망 운용 시나리오에 대한 시험을 통해 최적의 운용방안을 도출하였다.

• 대한교통학회지
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• 제29권2호
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• pp.7-14
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• 2011

본선 교통류 제어 방안 중 가변속도제어 모형을 제시하고 서울 내부순환로를 중심으로 효과를 검증하였다. 차량 검지기로부터 수집된 데이터 보정 및 평활화 수행후 패턴분석을 통해 도시고속도로의 평일 상태를 4가지로 분류하고 중심 값을 산출하였다. 그리고 분석단위의 상태를 판단하기 위한 상태변수로 전이교통량, 평균밀도, 평균속도를 설정하였으며 제시된 모형과 시나리오에 근거하여 검증한 결과 안전성 및 효율성을 향상시킬 수 있었다. 또한 유입교통량에 따라 가변속도제어의 감속 정도와 유효 적용시간을 산출하였다.

• Korean Journal of Hydrosciences
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• 제5권
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• pp.17-31
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• 1994

Because of the Keumkangsan-Dam and the Peace-Dam constructed in recent years, it is expected that the peak flood discharge and the peak flood stage at the Hwachun-Dam site have been changed. In this study, two methods were used to simulate and compare the effects of the upstream dam construction on the change of the discharge and the stage. One is the storage function method widely used for the hydrological routing in the country. The other is the DWOPER(Dynamic Wave Operational Model) package conducted on four different scenarios: (1) before the construction of the Keumkangsan-Dam and the Peace-Dam; (2) the exclusion of the Keumkangsan-Dam watershed (before the construction of the Peace-Dam); (3) the exclusion of the Keumkangsan-Dam watershed (after the construction of the Peace-Dam) ; (4) the exclusion of the Peace-Dam watershed. The results of the four test cases from the two methods show that the peak flood discharge and the peak flood stage at the Hwachun-Dam site are reduced due to the construction of the Peace-Dam. From these findings, it is suggested that the operational criteria for the optimal dam-operation of the Hwachun-Dam need to be modified.