• 한국수소및신에너지학회논문집
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• 제24권2호
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• pp.150-159
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• 2013

To enhance the performance of SEWGS system by holding the WGS catalyst in a SEWGS reactor using bed inserts, effects of insert geometry and shape of WGS catalysts on CO conversion were measured and investigated. Small scale fluidized bed reactor was used as experimental apparatus and WGS catalyst (particle and tablet) and sand were used as bed materials. The parallel wall type and cross type bed inserts were used to hold the WGS catalysts. The CO conversion with steam/CO ratio was determined based on the exit gas analysis. The measured CO conversion using the bed inserts showed high value comparable to physical mixing cases. Moreover, gas flow direction was confirmed by bed pressure drop measurement for each case. Most of input gas flowed through the catalyst side when we charged tablet type catalyst into the bed insert and this can cause low $CO_2$ capture efficiency because the possibility of contact between input gas and $CO_2$ absorbent is low in this case. New bed insert geometry was proposed based on the results from this study to enhance contact between input gas and WGS catalyst and $CO_2$ absorbent.

• 국제지역연구
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• 제21권1호
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• pp.303-324
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• 2017

유엔임무단에 파병되는 한국군의 평화활동 성과를 측정하는 현행평가방식에 대해 적절성, 타당성, 신뢰성문제가 불가피하게 제기되고 있다. 이에 본고는 유엔현장임무단과 국제개발커뮤니티에서 널리 채택한 바 있는 성과기반평가(RBE)모델을 한국군 파병부대의 평화활동에 부합하도록 보완 및 적용하는 방안을 제시하고자 한다. 연구결과, 논리체계모형을 토대로 기획과 평가단계를 통합하는 RBE모델을 토대로 파병 전기획, 파병기간 중 모니터링과 단계적 평가, 파병 후 영향평가의 사이클로 귀결되는 틀을 제안하였다. 둘째, 현행 한국군 평화활동의 모니터링과 평가체계를 RBE모델 기준을 적용하여 검증한 결과, 평가조직 운용 및 논리체계모형에 해당되는 요소들이 기준을 충족하지 못하거나 부분적으로만 충족하였고 파병사후 영향평가는 거의 수행하지 않은 것으로 나타났다. 결론적으로 전술한 문제점들의 해결방안과 민-관-군 분야 전문가가 참여하는 합동조사단 운용을 정책제안으로 제시하였다.

• 융합정보논문지
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• 제11권7호
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• pp.31-38
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• 2021

본 논문은 감성 분석에 사용되는 RNN 모델의 최적화를 얻기 위한 성능분석을 위하여 하이퍼파라미터 튜닝에 따른 손실과 정확도의 추이를 관찰하여 모델과의 상관관계를 연구하였다. 연구 방법으로는 시퀀셜데이터를 처리하는데 가장 최적화된 LSTM과 Embedding layer로 히든레이어를 구성한 후, LSTM의 Unit과 Batch Size, Embedding Size를 튜닝하여 각각의 모델에 대한 손실과 정확도를 측정하였다. 측정 결과, 손실은 41.9%, 정확도는 11.4%의 차이를 나타내었고, 최적화 모델의 변화추이는 지속적으로 안정적인 그래프를 보여 하이퍼파라미터의 튜닝이 모델에 지대한 영향을 미침을 확인하였다. 또한 3가지 하이퍼파라미터 중 Embedding Size의 결정이 모델에 가장 큰 영향을 미침을 확인하였다. 향후 이 연구를 지속적으로 이어나가 모델이 최적의 하이퍼파라미터를 직접 찾아낼 수 있는 알고리즘에 대한 연구를 지속적으로 이어나갈 것이다.

• 한국초전도ㆍ저온공학회논문지
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• 제24권3호
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• pp.57-61
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• 2022

One of the major applications of REBCO coated conductor (CC) tapes is in superconducting magnets or coils that are designed for high magnet fields. For such applications, the CC tapes were exposed to a high level of stresses which includes uniaxial tensile or transverse compressive stresses resulting from a large magnetic field. Thus, CC tapes should endure such mechanical load or deformation that can influence their electromechanical performance during manufacturing, cool-down, and operation. It has been reported that the main cause of critical current (I_c) degradation in CC tapes utilized in coil windings for superconducting magnets was the delamination due to transversely applied stresses. In most high-magnetic-field applications, the operating limits of the CC tapes will likely be imposed by the electromechanical properties together with its I_c dependence on temperature and magnetic field. In this study, we examined the influence of the transverse compressive stress on the I_c degradation behaviors in various commercially available CC tapes which is important for magnet design Four differently processed REBCO CC tapes were adopted to examine their I_c degradation behaviors under transverse compression using an anvil test method and a newly developed instantaneous I_c measurement system. As a result, all REBCO CC tapes adopted showed robustness against transverse compressive stresses for REBCO coils, notably at transverse compressive stresses until 250 MPa. When the applied stress further increased, different Ic degradation behaviors were observed depending on the sample. Among them, the one that was fabricated by the IBAD/MOCVD process showed the highest compressive stress tolerance.

• 한국초전도ㆍ저온공학회논문지
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• 제24권3호
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• pp.47-51
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• 2022

With the innovative development of bio, pharmaceutical, and semiconductor technologies, it is essential to demand a next-generation transfer system that minimizes dust and vibrations generated during the manufacturing process. In order to develop dust-free and non-contact transfer systems, the high temperature superconductor (HTS) bulks have been applied as a magnet for levitation. However, sintered HTS bulk magnets are limited in their applications due to their relatively low critical current density (J_c) of several kA/cm² and low mechanical properties as a ceramic material. In addition, during cooling to cryogenic temperatures repeatedly, cracks and damage may occur by thermal shock. On the other hand, the bulk magnets made by stacked HTS tapes have various advantages, such as relatively high mechanical properties by alternate stacking of the metal and ceramic layer, high magnetic levitation performance by using coated conductors with high J_c of several MA/cm², consistent superconducting properties, miniaturization, light-weight, etc. In this study, we tried to fabricate HTS tapes stacked bulk magnets with 60 mm × 60 mm area and various numbers of HTS tape stacked layers for magnetic levitation. In order to examine the levitation forces of bulk magnets stacked with HTS tapes from 1 to 16 layers, specialized force measurement apparatus was made and adapted to measure the levitation force. By increasing the number of HTS tapes stacked layers, the levitation force of bulk magnet become larger. 16 HTS tapes stacked bulk magnets show promising levitation force of about 23.5 N, 6.538 kPa at 10 mm of levitated distance from NdFeB permanent magnet.

• 센서학회지
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• 제30권4호
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• pp.250-254
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• 2021

A highly sensitive and selective non-dispersive infrared (NDIR) carbon dioxide gas sensor requires achieving high transmittance and narrow full width at half maximum (FWHM), which depends on the interface of the optical filter for precise measurement of carbon dioxide concentration. This paper presents the design, simulation, and fabrication of a Fabry-Perot filter based on a distributed Bragg reflector (DBR) for a low-cost NDIR carbon dioxide sensor. The Fabry-Perot filter consists of upper and lower DBR pairs, which comprise multilayered stacks of alternating high- and low-index thin films, and a cavity layer for the resonance of incident light. As the number of DBR pairs inside the reflector increases, the FWHM of the transmitted light becomes narrower, but the transmittance of light decreases substantially. Therefore, it is essential to analyze the relationship between the FWHM and transmittance according to the number of DBR pairs. The DBR is made of silicon and silicon dioxide by RF magnetron sputtering on a glass wafer. After the optimal conditions based on simulation results were realized, the DBR exhibited a light transmittance of 38.5% at 4.26 ㎛ and an FWHM of 158 nm. The improved results substantiate the advantages of the low-cost and minimized process compared to expensive commercial filters.

• Asia Marketing Journal
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• 제14권4호
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• pp.57-75
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• 2013

It is a well-established theory that emotion is influential in cognitive processing. Extensive prior research on emotion has shown that emotional factors, such as affect, mood, and feeling, play as information indicating whether he or she has enough knowledge. Most of their findings focused on the effect of emotional valence (i.g., one's subjective positivity or negativity related with the emotion). Recently, several studies on emotion suggest that there is another dimension of emotion, which affects the type of cognitive processing. The studies argue that emotional certainty facilitates heuristic processing, whereas emotional uncertainty promotes systematic processing. Based on the findings, current study examines the effect of certainty on attitudes and recall. Specifically, the authors investigate the effect of certainty on how much effort individuals use to process advertising information and how certainty affects attitude formation toward the advertised product. The authors also focus on recall to clarify the working mechanism of certainty on attitudes, because recall performance reflects the depth of information processing. Based on previous findings, the authors hypothesize that uncertainty (vs. certainty) leads to more favorable attitudes as well as better recall, and conduct an experiment using a fictitious advertisement with 218 participants. The results confirm the predicted effects of certainty only on attitudes not recall. A possible explanation of this discrepancy between attitudes and recall lies in the measurement method, unaided recall. To rule out this possibility, the authors perform an additional analysis with the participants who recall any correct information of the target advertisement. The results show certainty has a negative effect on both attitudes and recall. A bootstrapping test reveals that recall mediates the effect of certainty on attitudes. This result confirms that certainty decreases elaboration, which in turn leads to less favorable attitudes relative to uncertainty. Additionally, our data shows the association among certainty, recall, and attitudes by showing the indirect effect of certainty on attitudes via recall. This research encourages practitioners in the field to emphasize that they should focus on target audiences' emotional certainty before they provide the persuasive message, by showing that uncertainty promotes effortful processing, which in turn leads to better memory and more favorable attitudes.

• 사물인터넷융복합논문지
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• 제9권6호
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• pp.37-44
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• 2023

인터스트리4.0의 주요 기술인 인간-로봇 협업은 작업자의 안전을 보장하기 위한 추가적인 조치들이 필요하다. 협동로봇과 작업자간 충돌을 회피하는 기존 방식은 주로 로봇에 부착된 센서와 카메라를 기반으로 총돌을 탐지한다. 이러한 방식은 로봇, 사람 물체를 지속적으로 추적하고 충돌회피를 위한 복잡한 알고리즘이 필요하며, 작업 환경 변화에 빠르게 대응하지 못하는 단점이 있다. 본 논문은 인간과 로봇이 협업하는 과정에서 작업자가 위험을 느낄 때의 감정을 인식하여 협동로봇과의 충돌을 방지할 수 있는 웹 기반 플랫폼을 개발하였다. 이를 위해 웨어러블 뇌파장치를 이용하여 감정 관련 뇌파를 수집하고 저장하는 웹 기반 애플리케이션을 개발하였으며, 중립/긍정/부정 감정의 특징을 추출하고 분류하는 딥러닝 모델을 제안하였다. 또한 분류된 감정에 따라 모터동작을 제어하는 사물인터넷 인터페이스 프로그램을 개발하였다. 구현된 시스템의 성능분석을 위해 공개 데이터세트와 실제 수집된 데이터 세트를 사용하여 제안한 딥러닝 모델의 성능을 분석하였다. 공개 데이터 세트의 경우 정확도는 96.8%이며, 실제 수집 데이터세트의 경우 정확도는 70.7%이다.

• Applied Microscopy
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• 제45권1호
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• pp.1-8
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• 2015

We have developed a new HD-2700 (Hitachi High-Technologies Corp., Japan) scanning transmission electron microscope (STEM) that includes an automatic aberration correction function, and a large-solid-angle energy-dispersive X-ray spectroscopy detector that enables high-resolution and sensitive analysis. For observation with atomic resolution, using spherical-aberration-corrected STEM, in order that satisfactory performance of the device can be achieved readily, and within a short time, irrespective of the operator's skill level, a spherical-aberration-correction device with an automatic aberration-correction function was developed. This automatic aberration-correction function carries out the entire correction-related process (aberration measurement, selection and correction) automatically, with automatic selection of the aberrations that require correction, and automatic measurement of the appropriate corrections.

• 한국초등수학교육학회지
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• 제15권1호
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• pp.57-75
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• 2011

본 연구는 초등수학 5-나 단계의 수와 연산 영역, 도형 영역, 측정 영역에서 수학적 글쓰기의 한 방법인 상호글쓰기3) 활동이 학생들의 수학 학업성취도 및 성향에 미치는 영향을 알아보기 위하여 수행된 실험연구이다. 이를 위해 대구광역시 달서구에 소재한 J초등학교 5학년 2 개 학급(실험집단 : 31명, 비교집단 : 31명)을 대상으로 약 6주간 수행되었다. 본 연구에서는 수학 학업성취도 및 성향을 측정하는 두 검사도구를 선정하여 사전 사후 검사를 실시하였다. 사전검사의 분석 결과 두 집단은 동질집단이었고 사후검사는 연구문제 1과 2의 효과를 확인하는데 사용되었으며 검사결과는 t-검정으로 분석하였다. 연구결과는 아래와 같다. 첫째, 상호글쓰기 활동은 학업성취도에 있어 유의미한 결과가 나타나지 않았지만 통계적으로 어느 정도 차이가 있음을 확인할 수 있었고, 수와 연산 영역에 있어서는 유의미한 차이를 확인할 수 있었다. 둘째, 수학적 성향의 하위 영역인 수학적 자신감, 융통성, 의지, 호기심, 반성, 가치 모두에 있어서 긍정적인 영향을 받는 것으로 나타났다.