• Nuclear Engineering and Technology
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• 제51권4호
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• pp.1024-1031
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• 2019

The Molten Salt Fast Reactor (MSFR) with its liquid circulating fuel and its fast neutron spectrum calls for a new safety approach including technological neutral methodologies and analysis tools adapted to early design phases. In the frame of the Horizon2020 program SAMOFAR (Safety Assessment of the Molten Salt Fast Reactor) a safety approach suitable for Molten Salt Reactors is being developed and applied to the MSFR. After a description of the MSFR reference design, this paper focuses on the identification of the Postulated Initiating Events (PIEs), which is a core part of the global assessment methodology. To fulfil this task, the Functional Failure Mode and Effect Analysis (FFMEA) and the Master Logic Diagram (MLD) are selected and employed separately in order to be as exhaustive as possible in the identification of the initiating events of the system. Finally, an extract of the list of PIEs, selected as the most representative events resulting from the implementation of both methods, is presented to illustrate the methodology and some of the outcomes of the methods are compared in order to highlight symbioses and differences between the MLD and the FFMEA.

• 한국정보처리학회논문지
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• 제7권5호
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• pp.1401-1408
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• 2000

소프트웨어 개발 초기 단계의 문제점이 개발 후반부 산물의 품질에 심각한 영향을미치기 때문에 설계 명세를 이용하여 위험 부분을 예측하는위험도 예측 모델은 전체 시스템 개발비용을 낮추는 데 중요한 역할을 하고 있으며, 이러한 예측 모델은 결과 산물이 매우 크고 실행 정확성이 요구되는통신 소프트웨어 같은 실시간 시스템 설계에 더욱 필요하다. 판별분석, 인공신경망, 분류트리 등의 기법들을 이용한 모델들이 제안되었으나 이들은 결과에 대한 원인 분석의 어려움, 낮은 확장성 등의 문제점들을 지니고 있었다. 본 논문에서는 유전자 알고리즘에 의해 구축된 퍼지 규칙 베이스를 이용한 위험도 예측 모델을 제안한다. 제안 모델은 예측 결과에 대한 원인 분석이 용이하고 높은 확정성과 적용성을 지니고 규칙수에 대한 제안이 없다. 이러한 내부특성들 비교의 모의 실을 통한 예측 정확도 비교를 통해 제안 모델이 타 모델들보다 우수함을 보였다.

• Physical Therapy Rehabilitation Science
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• 제13권1호
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• pp.53-70
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• 2024

Background: The conventional deadlift is a popular exercise for enhancing trunk, core, and lower extremity strength. However, its use in sports medicine is constrained by concerns of lumbar injuries, despite evidence supporting its safety and rehabilitative benefits. To optimize muscle activation using resistive bands in variable resistance therapy, we explored their feasibility in the deadlift. Design: Comparative experimental design Methods: Surface electromyography recorded muscle activity in the trunk and lower extremities during lifting, with normalization to the isometric Floor Lift using Maximal Voluntary Contraction. Kinematics were measured using inclinometer sensors to track hip and trunk sagittal plane angles. To prevent fatigue, each subject only used one of the three pairs of bands employed in the study. Results: Our study involved 45 healthy subjects (mean age: 30.4 ± 6.3 years) with similar baseline characteristics, except for years of lifting and strength-to-years-of-lifting ratio. Various resistance band groups exhibited significantly higher muscle activity than conventional deadlifts during different phases. The minimal resistance band group had notably higher muscle activity in the trunk, core, and lower extremity muscles, particularly in the end phase. The moderate resistance band group showed increased muscle activity in the mid-and end-phases. The maximum resistance band group demonstrated greater muscle activity in specific muscles during the early phase and overall higher activity in all trunk and lower extremity muscles in the mid and end phases of the deadlift (p<0.05). Conclusion: Our findings provide valuable insights into muscle activation with various resistance bands during deadlift exercise in clinical and gym settings. There appears to be a dose-response relationship between increased resistance bandwidth, external load, myoelectric activation, and range.

• 물과 미래
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• 제18권3호
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• pp.253-264
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• 1985

근본적으로 저수지의 Storage-Yield 관계를 해석하는 데는 두가지 관점이 있다. 가장 보편적인 관점은 필요한 수요량을 공급하기 위하여 저수지의 필요저수용량을 결정하는 것이다. 이런 형태의 문제는 저수지의 계획이나 초기 설계단계에서 보통 생긴다. 두 번째 관점은 주어진 저수용량에 대한 방류량의 결정이며, 이것은 최종 설계나 더 상세한 분석을 위한 현존 저수지의 재평가에서 자주 생긴다. 본 연구의 목적은 저수지의 설계나 운영을 위한 Storage-Yield 관계를 산정하는 현재의 방법론을 개선하는 것이다. 저수지의 Storage-Yield 관계를 해석하느 s가장 적합한 기법을 찾기 위하여 잔차누가곡선기법(Residual mass curve technique), 개선된 저류량기법(Low flow technique)과 TPM 기법(Transition probability matrix technique)이 검토되었다. 저수지의 Storage-Yield 관계를 해석하는데 있어서 홍천댐 건설예정지점의 1917∼1940년 월유입량 자료와 Thomas-Fiering 모델에 의해 모의 발생된 자료를 가지고 위의 세가지 기법을 상세히 검토하였다. 저수지의 Storage-Yield 관계를 폭넓게 검토한 결과, 잔차누가곡선기법과 저류량기법은 예비 설계에 타당하며, TPM 기법은 월별 혹은 계절별 수요변동을 고려할 수 있기 때문에 최종 설계에 타당한 기법임을 알 수 있다.

• 한국항공우주학회지
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• 제40권3호
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• pp.258-263
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• 2012

본 논문은 천리안 위성의 추진계를 간략하게 소개하고 천리안 위성의 발사 및 초기 위성운용 수행 임무 중 위성 추진계의 일련의 과정에서 측정된 원격측정치를 제시한다. 일부 원격측정치는 기 개발된 프로그램의 계산결과와 비교하였다. 추진계의 압력변화는 주로 두단계로 구성된다. 첫 번째 단계는 위성 추진계의 초기화, 즉 안전을 위해서 추진제 탱크 후 단부터 추력기 상단까지 충전된 헬륨 가스를 진공인 우주공간으로 빼는 배출단계를 시작으로, 이 빈 배관망에 산화제와 연료를 각각 채우는 충전단계를 거치고 마지막으로 추진제 탱크의 압력을 일정한 압력까지 올리는 가압단계이다. 두 번째 단계는 목표궤도에 이를 때까지 수행하는 액체원지점엔진의 연소 단계이며, 이 단계에서는 추진제 탱크의 압력을 일정하게 유지 하기 위해서 가압제인 헬륨을 사용한다. 이 프로그램은 향후에 개발되는 정지 궤도복합위성의 기초 설계자료 생성에 사용할 수 있을 것이다.

• 대한건축학회논문집:구조계
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• 제34권4호
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• pp.75-82
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• 2018

BIM(Building Information Modeling) based design process can initiatively conduct a task through all phases from early design step to construction and maintenance step. Also BIM efficiently manage the building's energy by reflecting 3D design and construction life cycle. This paper proposes an efficient process to build AHU's BIM-based library. This study involves analyzing an AHU model for development of design module, and making the template model using the same 12 parts including the shapes of ducts, doors and frames. In consideration of each shape's direction and the status of existence, which are detailed shapes of parts upon making the template model, all the shapes of the AHU model can be expressed. By applying parametric modeling to the template model, a quick and precise modification and transformation can be conducted, thus the efficiency is enhanced. A user selects an AHU model from a 2D model selection program, and extracts shape information. The final AHU shape is completed through the automation work of unnecessary shape deletion by bringing the extracted shape information to the template model. This enables the user to build efficient AHU's BIM-based library, since the quick and precise modification and transformation of the template model are possibile, and all AHU model shapes can be expressed.

• Journal of Astronomy and Space Sciences
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• 제41권1호
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• pp.43-60
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• 2024

Korea Pathfinder Lunar Orbiter (KPLO) is South Korea's first space exploration mission, developed by the Korea Aerospace Research Institute. It aims to develop technologies for lunar exploration, explore lunar science, and test new technologies. KPLO was launched on August 5, 2022, by a Falcon-9 launch vehicle from cape canaveral space force station (CCSFS) in the United States and placed on a ballistic lunar transfer (BLT) trajectory. A total of four trajectory correction maneuvers were performed during the approximately 4.5-month trans-lunar cruise phase to reach the Moon. Starting with the first lunar orbit insertion (LOI) maneuver on December 16, the spacecraft performed a total of three maneuvers before arriving at the lunar mission orbit, at an altitude of 100 kilometers, on December 27, 2022. After entering lunar orbit, the commissioning phase validated the operation of the mission mode, in which the payload is oriented toward the center of the Moon. After completing about one month of commissioning, normal mission operations began, and each payload successfully performed its planned mission. All of the spacecraft operations that KPLO performs from launch to normal operations were designed through the system operations design process. This includes operations that are automatically initiated post-separation from the launch vehicle, as well as those in lunar transfer orbit and lunar mission orbit. Key operational procedures such as the spacecraft's initial checkout, trajectory correction maneuvers, LOI, and commissioning were developed during the early operation preparation phase. These procedures were executed effectively during both the early and normal operation phases. The successful execution of these operations confirms the robust verification of the system operation.

• 한국시뮬레이션학회논문지
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• 제16권2호
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• pp.65-74
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• 2007

가상생산기술은 신제품의 개발, 새로운 장비 개발 및 새로운 제조시스템 개발에 유용한 도구이며, 특히 3D 시뮬레이션 기술은 가상생산의 핵심기술이다. 3D 시뮬레이션 기술은 기계적 시뮬레이션 기술과 이산사건 시뮬레이션 기술로 구분할 수 있다. 본 논문에서는 휴대폰 카메라에 장착되는 렌즈모듈 조립을 생산하는 국내 회사의 사례를 소개한다. 이 회사에서는 렌즈모듈 조립공정을 현재 수작업으로 하고 있는데 자동화시스템을 개발하기로 결정하였으며 이를 위해 3D 시뮬레이션 기술을 도입하기로 하였다. 3D 시뮬레이션 기술은 시스템 개념설계단계에서부터 적용이 되었는데, 단위 장비 개발을 위해서는 $CATIA^{(R)}$와 $IGRIP^{(R)}$이 활용되었으며, 시스템 설계를 위해서는 이산사건 시뮬레이션 도구인 $QUEST^{(R)}$가 활용되었다. 논문의 목적은 새로운 자동화 설비의 기술적. 경제적 타당성을 검증하는 것이다. 개발결과 takt time 이 기존의 수작업에 비해 4분의 1 수준으로 감소되었으며, 이에 따른 작업자 인원도 대폭 감소되었다.

• 정보처리학회논문지D
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• 제9D권1호
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• pp.81-90
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• 2002

More than 50% of defects and errors in the software development projects are related to the requirements[14]. But the development methodologies can not provide enough supports to the requirements management and changes. In the real world, the requirements keep changing as the requirements at the early development phase are usually incomplete, the developer′s understanding of the problem will be constantly changed during the software process, and new requirements may emerge with the organizational and environmental changes. In this paper, a requirements management process that can be integrated into the development methodologies is proposed to extend the requirements management over the whole development life-cycle and to support the requirements changes at the design/implementation/test phases. To evaluate the proposed process, it was compared to the existing requirements managements processes and models, and examined through a integration test with a widely used development methodology "MaRMI" to show the expected improvements at each development phase.

• Animal Bioscience
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• 제36권8호
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• pp.1228-1240
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• 2023

Objective: This experiment was conducted to evaluate the effects of different levels of dietary crude protein (CP) on growth performance, blood profiles, diarrhea incidence, nutrient digestibility, and odor emission in weaning pigs. Methods: A total of 240 weaning ([Yorkshire×Landrace]×Duroc) pigs (8.25±0.050 kg body weight [BW]) were assigned to six treatments based on sex and initial BW, with five replicates of eight pigs per pen in a randomized complete block design. Experimental diets with different crude protein levels for early and late weaning phases were as follows: i) CP16, corn-soybean-based diet containing 16%/15% CP; ii) CP17, corn-soybean-based diet containing 17%/16% CP; iii) CP18, corn-soybean-based diet containing 18%/17% CP; iv) CP19, corn-soybean-based diet containing 19%/18% CP; v) CP20, corn-soybean-based diet containing 20%/19% CP; and vi) CP21, corn-soybean-based diet containing 21%/20% CP. Results: In the early weaning period, average daily feed intake increased when the dietary CP level decreased (linear, p<0.05). During the entire experimental period, average daily gain and the gain to feed ratio decreased when the dietary CP level increased (linear, p<0.01). Additionally, a decrease in dietary CP level resulted in a linear increase in final BW (linear, p<0.05). In the early and late weaning periods, blood urea nitrogen (BUN) decreased when the dietary CP level decreased (linear, p<0.01). There were no significant differences in creatinine, glucose, total protein, triglyceride or insulin-like factor-1 levels over the experimental period. The concentrations of immunoglobulin A (IgA) and IgG were not significantly affected by dietary CP levels during the experimental period. In the early weaning period, fecal and urine N decreased when the dietary CP level decreased (linear, p<0.01). No differences in nutrient digestibility among the treatments during the early weaning period were found. Throughout the whole experimental period, when the dietary CP level decreased in the weaning pig diet, the diarrhea incidence decreased linearly (linear, p<0.01). Throughout the whole experimental period, when the dietary CP level decreased in the weaning pig diet, ammonia, amines and hydrogen sulfide decreased linearly (linear, p<0.01). Conclusion: Reducing dietary CP could decrease diarrhea incidence, the concentration of BUN in serum and odor emission in manure. Furthermore, it could improve N excretion in feces and urine and growth performance in weaning pigs.