• 한국수산과학회지
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• 제54권4호
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• pp.404-410
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• 2021

Although, mouse bioassay for the monitoring of azaspiracids (AZAs) toxins in shellfish has been used previously, the reported method has low sensitivity and it is time-consuming. Recently, there is an interest in the quantitative analysis of AZAs using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The purpose of this study is to verify the simultaneous analysis of AZAs in shellfish and tunicate in Korea using LC-MS/MS. To validate the method, linearity, limit of detection (LOD), limit of quantification (LOQ), precision, accuracy, and repeatability were determined. All standard compounds were analyzed within 7 min. The correlation coefficients (R²) of the standard solution was higher than 0.9995 (within the range of 0.8-10.0 ㎍/L). The LODs and LOQs of AZAs in shellfish were 0.08-0.16 ㎍/kg and 0.23-0.50 ㎍/kg, respectively. The accuracy and precision of the method for determining AZAs in shellfish were 87.1-93.0% and 1.23-4.91%, respectively. Consequently, the verified LC-MS/MS method is suitable to analyze AZAs in shellfish and tunicates in Korea.

• 한국융합학회논문지
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• 제12권12호
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• pp.161-167
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• 2021

본 연구의 목적은 팀 기반 학습활동에서 인성교육이 자연스럽게 습득될 수 있도록 방법론적 접근을 통한 해결책을 제공하는 것이다. 2021년 봄 학기에 두 그룹 총 69명의 대학생을 대상으로 실험반은 교양영어 프로그램과 팀 기반 학습활동을 융합하여 강의를 진행하였고 통제반은 교양영어 프로그램에 맞춘 강의중심 수업을 실시하여 팀 활동이 인성교육 덕목에 영향을 줄 수 있는지를 연구하였다. 연구 결과, 실험반(p<.001)의 사후 테스트 결과에서 인성덕목 총점이 크게 향상되었다. 팀 기반 학습의 하위 항목인 리더십, 신뢰도, (과제)수행 및 책임감 간상호 밀접하게 상관관계가 있었으며 인성교육의 하위 항목인 자기조절, 배려, 소통, 자존감, 책임감에 대한 사전 및 사후 테스트 결과 통계적으로 유의미한 것으로 나타났다. 따라서 강의중심 수업보다는 학생들이 직접 참여한 팀 활동을 통한 수업은 인성교육에 효과적인 영향을 주었다. 다만, 현 연구는 모수가 제한적이기 때문에 보다 확장적인 심층 연구가 필요하며, 향후 다양한 교수법이 적용된 인성교육의 효과성에 대한 검증이 이루어졌으면 한다.

• 한국컴퓨터정보학회논문지
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• 제26권10호
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• pp.167-172
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• 2021

세월호 사고 이후 해양안전에 대한 국민적인 관심이 높아졌지만 해양레저관광인구가 증가됨에 따라 해양사고로 인한 인명피해가 갈수록 증가되는 추세이 있어 해양안전교육이 시급한 실정이다. 그러나 해양안전교육관련 시설이 지리적으로 우리나라 서쪽에 편향이 되어 있어 교육에 있어 지역적 불균형이 심각한 상황이다. 따라서 본 연구는 우리나라 동남권 특히, 부산에 위치한 한국해양수산연수원의 유휴시설을 해양안전교육센터로 활용하여 지역적 교육 불균형을 해소하고 교육콘텐츠 개발 방안과 예산과 전문인력 확보에 따른 문제점에 관하여 해결방안을 제시하였다. 또한 중력모형을 활용하여 수요추정한 결과 연간 15만명에서 13만명에 이를것으로 추정되었다. 본 연구는 객관적인 검증방법을 활용하여 기존 유휴부지를 해양안전교육센터로서 활용하는 정책적 제언에 관하여 충분한 사회정책적 타당성을 입증하였으며 향후 정책추진에 실질적 기여를 할 수 있을 것으로 기대된다.

• 한국BIM학회 논문집
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• 제11권3호
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• pp.22-33
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• 2021

In order to maximize the use of BIM, all data related to individual elements in the model must be correctly assigned, and it is essential to check whether it corresponds to the IFC entity classification. However, as the BIM modeling process is performed by a large number of participants, it is difficult to achieve complete integrity. To solve this problem, studies on semantic integrity verification are being conducted to examine whether elements are correctly classified or IFC mapped in the BIM model by applying an artificial intelligence algorithm to the 2D image of each element. Existing studies had a limitation in that they could not correctly classify some elements even though the geometrical differences in the images were clear. This was found to be due to the fact that the geometrical characteristics were not properly reflected in the learning process because the range of the region to be learned in the image was not clearly defined. In this study, the CRF-RNN-based semantic segmentation was applied to increase the clarity of element region within each image, and then applied to the MVCNN algorithm to improve the classification performance. As a result of applying semantic segmentation in the MVCNN learning process to 889 data composed of a total of 8 BIM element types, the classification accuracy was found to be 0.92, which is improved by 0.06 compared to the conventional MVCNN.

• 한국전자통신학회논문지
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• 제16권5호
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• pp.789-798
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• 2021

본 연구는 레이다 시스템의 성능 검증 및 개선을 위한 표적 신호 모의장비의 표적별 레이다반사면적(RCS) 데이터의 수집 및 분석을 목적으로 민항기(B-747, B-737) 및 전투기(F-16) 기종에 대한 VHF 대역의 모노스태틱/바이스태틱 RCS를 전자기장 분석한 연구이다. 분석에 앞서, 전자기장 분석 도구들에 대한 데이터 교차 검증 및 분석 시간 비교를 통해 소요 시간을 최소화하였으며, 분석 해상도에 따른 보간 오차를 검토하여 분석범위를 선정하였다. 각 기종별로 획득된 RCS 데이터는 입/반사 고각 및 주파수별로 나누어 분석하였으며, 기체 모양 및 입/반사 각도에 따른 RCS 특징을 기술하였다. 마지막으로 RCS 분포 히스토그램을 통해 각 기종별 통계적 RCS 분포값을 제시한다. 향후 본 연구를 통해 획득한 RCS 데이터베이스는 VHF 대역 레이다 시스템의 항적 신호 모의를 위한 신호모사장치에 활용할 예정이다.

• Nuclear Engineering and Technology
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• 제51권5호
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• pp.1406-1416
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• 2019

In this research, a multi-slit prompt-gamma camera was developed to locate the distal dose falloff of the proton beam spots in spot scanning proton therapy. To see the performance of the developed camera, therapeutic proton beams were delivered to a solid plate phantom and then the prompt gammas from the phantom were measured using the camera. Our results show that the camera locates the 90% distal dose falloff (= d90%), within about 2-3 mm of error for the spots which are composed $3.8{\times}10^8$ protons or more. The measured location of d90% is not very sensitive to the irradiation depth of the proton beam (i.e., the depth of proton beam from the phantom surface toward which the camera is located). Considering the number of protons per spot for the most distal spots in typical treatment cases (i.e., 2 Gy dose divided in 2 fields), the camera can locate d90% only for a fraction of the spots depending on the treatment cases. However, the information of those spots is still valuable in that, in the multi-slit prompt-gamma camera, the distal dose falloff of the spots is located solely based on prompt gamma measurement, i.e., not referring to Monte Carlo simulation.

• 대한조선학회논문집
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• 제56권1호
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• pp.82-93
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• 2019

In this paper, the ductile fracture criteria for a marine structural steel (EH36) are presented and validated. The theoretical background of the recently developed Hosford-Coulomb (HC) fracture strain model and the DSSE fracture strain model which was developed to apply to the shell elements is described. In order to accurately estimate the flow stress in the large strain range up to the fracture, the material constants for the combined Swift-Voce constitutive equation were derived by the numerical analyses of the smooth and notched specimens made from the EH36 steel. As a result of applying the Swift-Voce flow stress to the other notched specimen model, a very accurate load - displacement curve could be derived. The material constants of the HC fracture strain and DSSE fracture strain models were independently calibrated based on the numerical analyses for the smooth and notch specimen tests. The user subroutine (VUMAT of Abaqus) was developed to verify the accuracy of the combined HC-DSSE fracture strain model. An asymmetric notch specimen was used as verification model. It was confirmed that the fracture of the asymmetric specimen can be accurately predicted when a very small solid elements are used together with the HC fracture strain model. On the other hand, the combined HC-DSSE fracture strain model can predict accurately the fracture of shell element model while the shell element size effect becomes less sensitive.

• Smart Structures and Systems
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• 제23권2호
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• pp.141-153
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• 2019

This research deals with wave propagation of the functionally graded (FG) nano-beams based on the nonlocal elasticity theory considering surface and flexoelectric effects. The FG nano-beam is resting in Winkler-Pasternak foundation. It is assumed that the material properties of the nano-beam changes continuously along the thickness direction according to simple power-law form. In order to include coupling of strain gradients and electrical polarizations in governing equations of motion, the nonlocal non-classical nano-beam model containg flexoelectric effect is used. Also, the effects of surface elasticity, dielectricity and piezoelectricity as well as bulk flexoelectricity are all taken into consideration. The governing equations of motion are derived using Hamilton principle based on first shear deformation beam theory (FSDBT) and also considering residual surface stresses. The analytical method is used to calculate phase velocity of wave propagation in FG nano-beam as well as cut-off frequency. After verification with validated reference, comprehensive numerical results are presented to investigate the influence of important parameters such as flexoelectric coefficients of the surface, bulk and residual surface stresses, Winkler and shear coefficients of foundation, power gradient index of FG material, and geometric dimensions on the wave propagation characteristics of FG nano-beam. The numerical results indicate that considering surface effects/flexoelectric property caused phase velocity increases/decreases in low wave number range, respectively. The influences of aforementioned parameters on the occurrence cut-off frequency point are very small.

• 한국지리정보학회지
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• 제22권1호
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• pp.114-128
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• 2019

본 연구는 한반도 분할과 관련된 경계에 대해 공간적으로 분석한 것이다. 북위 $38^{\circ}$선에 대한 추출과 정전협정 전문의 부록의 지도를 디지타이징 함으로써 그 범위를 추출하였고, 정전협정 전문과 부록, 유엔사 규정 등 근거로 하여 보다 정확한 범위를 추출하고 잘못된 정보에 대해 올바르게 분석하고자 하였다. 비무장지대의 범위는 UNC 551-4(2014)와 UNC 551-5(2015)에 의거 남방한계선의 위치 변경이 없음과 비무장지대 내 군사정전위원회 본부구역이 제외됨을 확인하였다. 그 결과 비무장지대의 면적은 $889.7km^2$로 측정되었다. 군사분계선과 한강하구수역의 표식물을 확인하였으며, 특히 군사분계선의 표식물의 간격은 관리주체에 따라 다름을 확인할 수 있었다. 본 연구를 기점으로 보다 정확한 자료로써 공신력 있는 기관에서의 검증을 거쳐 DMZ 및 접경지역 연구, 교육에서 필요한 기초자료로서 활용할 수 있을 것이다.

• Ocean Systems Engineering
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• 제8권4호
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• pp.427-439
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• 2018

Floating Production Storage and Offloading (FPSO) units have the advantages of their ability to provide storage and offloading capabilities which are not available in other types of floating production systems. In addition, FPSOs also provide a large deck area and substantial topsides payload capacity. They are in use in a variety of water depths and environments around the world. It is a good solution for offshore oil and gas development in fields where there is lack of an export pipeline system to shore. However due to their inherently high motions in waves, they are limited in the types of risers they can host. The Low Motion FPSO (LM-FPSO) is a novel design that is developed to maintain the advantages of the conventional FPSOs while offering significantly lower motion responses. The LM-FPSO design generally consists of a box-shape hull with large storage capacity, a free-hanging solid ballast tank (SBT) located certain distance below the hull keel, a few groups of tendons arranged to connect the SBT to the hull, a mooring system for station keeping, and a riser system. The addition of SBT to the floater results in a significant increase in heave, roll and pitch natural periods, mainly through the mass and added mass of the SBT, which significantly reduces motions in the wave frequency range. Model tests were performed at the Korea Research Institute of Ships & Ocean Engineering (KRISO) in the fall of 2016. An analytical model of the basin model (MOM) was created in Orcaflex and calibrated against the basin-model. Good agreement is achieved between global performance results from MOM's predictions and basin model measurements. The model test measurements have further verified the superior motion response of LM-FPSO. In this paper, numerical results are presented to demonstrate the comparison and correlation of the MOM results with model test measurements. The verification of the superior motion response through model test measurements is also presented in this paper.