• 융합정보논문지
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• 제11권10호
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• pp.1-9
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• 2021

팬더믹의 영향으로 메타버스에 대한 관심이 증가하고 있으나, 지속성 있는 메타버스 운영을 위한 흥미 요인에 대한 이해는 부족한 실정이다. 따라서 본 연구는 사용자 커뮤니티 담화를 분석하여 메타버스 서비스의 흥미 요인을 밝히고자 한다. 이를 위해 게임 기반 메타버스의 대표 사례인 <모여봐요 동물의 숲>의 사용자 커뮤니티 담화를 수집해, Latent Dirichlet Allocation (LDA)를 활용해 토픽모델링을 실시했다. 추출된 토픽은 크래프팅과 성장을 위한 허들, 현실 연계 콘텐츠의 정보, 채집 활동과 수집 기록, 소셜라이징, 사용자 생성 콘텐츠와 자기표현, 시즈널 이벤트의 수행도, 캐릭터 상호작용과 슬롯 제한으로 나타났다. 게임 기반 메타버스의 흥미 요인은 성장과 확인 가능한 지표, 다양한 층위의 상호작용, 자기표현과 자유도, 현실세계와의 연결로 정리되고, 이를 통해 시간 기반 콘텐츠 운영, 운과 확률의 활용, 제약의 활용이라는 게임 기반 메타버스의 콘텐츠 기획 방향성을 도출했다. 본 연구는 실증적 담화 데이터를 활용해 흥미 요인을 도출했다는 것에 의의가 있다.

• 한국건설관리학회논문집
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• 제22권5호
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• pp.3-16
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• 2021

이 연구의 목적은 구성주의 교육이론 기반의 BIM/IPD(통합프로젝트수행)교육에 적합한 BIM협업 교육모델제안과 그 교육모델의 효율성을 검증하는 것이다. BIM/IPD기반 협업능력은 건설 전 분야 걸쳐 필요한 역량으로 보고 있다. '구성주의 협업 프로세스' 교육 방식을 실험군(구성주의 협업프로세스)과 대조군(빌딩스마트 협회 BIM 코디네이터 과정)에 적용하여 학습 전후의 상호작용 과정에서 학습효과의 개선을 인지측정(협업의 만족도, 협업의 수준)하고 실무능력(협업고도화지수측정)측정을 통한 '구성주의 협업프로세스'의 학습효과를 검증하는 것이다.

• Structural Engineering and Mechanics
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• 제69권3호
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• pp.257-268
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• 2019

Infills are as important members in structural design as beams, columns and braces. They have significant effect on structural behavior. Because of lots of variables in infills like material non-linear behavior, the interaction between frames and infill, etc., the infills performance during an earthquake is complicated, so have led designers do not consider the effect of infills in designing the structure. However, the experimental studies revealed that the infills have the remarkable effect on structure behavior. As if these effects ignored, it might occur soft-story phenomena, torsion or short-column effects on the structures. One simple and appropriate method for considering the infills effects in analyzing, is replacing the infills with diagonal compression strut with the same performance of real infill, instead of designing the whole infill. Because of too many uncertainties, codes and researchers gave many expressions that were not as the same as the others. The major intent of this paper is calculation the width of this diagonal strut, which has the most characteristics of infill. This paper by comprehensive on different parameters like the modulus of young or moment of inertia of columns presents a new formula for achieving the equivalent strut width. In fact, this new formula is extracted from about 60 FEM analyses models. It can be said that this formula is very efficient and accurate in estimating the equivalent strut width, considering the large number of effective parameters relative to similar relationships provided by other researchers. In most cases, the results are so close to the values obtained by the FEM. In this formula, the effect of out of plane buckling is neglected and this formula is used just in steel structures. Also, the thickness of infill panel, and the lateral force applied to frame are constant. In addition, this new formula is just for modeling the lateral stiffness. Obtaining the nearest response in analyzing is important to the designers, so this new formula can help them to reach more accurate response among a lot of experimental equations proposed by researchers.

• 디지털융복합연구
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• 제17권4호
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• pp.267-278
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• 2019

본 연구는 1인 게임방송 BJ에 대한 숭배와 인지된 동종 선호가 시청 충성도의 매개효과를 통해 게임 효능감에 미치는 영향을 실증적으로 검증하고자 하였다. 온라인 설문 조사를 통해 1인 게임방송 시청 경험이 있는 485명의 참가자들을 표본으로 수집하였으며, 수집된 데이터는 구조방정식모형 검증을 통해 분석되었다. 완전매개효과를 가정한 연구모형과 부분매개효과를 가정한 대안모형을 제시한 뒤 두 모형을 비교하였으며, 변인들 간의 직간접 효과를 분석하기 위해 부트스트래핑(bootstrapping)을 실시하였다. 연구 결과 BJ 숭배와 인지된 동종 선호는 시청 충성도의 완전매개효과를 통해 최종적으로 게임 효능감에도 유의미한 영향을 주는 것으로 밝혀졌다. 본 연구는 1인 게임방송이 시청자들의 게임 효능감 형성에 유의미한 영향을 미친다는 점을 밝혀내어 BJ에 대한 긍정적 인식을 제공하였다는 점에서 의의를 가진다.

• Nuclear Engineering and Technology
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• 제53권4호
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• pp.1119-1126
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• 2021

Spacer grid with mixing vane had been widely used in nuclear reactor core. One of the main feather of spacer grid with mixing vane was that strong swirl flow was formed after the spacer grid. The swirl flow not only changed the bubble generation in the near wall field, but also affected the bubble behaviors in the center region of the subchannel. The interaction between bubble and the swirl flow was one of the basic phenomena for the two phase flow modeling in fuel assembly. To obatin better understanding on the bubble behaviors in swirl flow, full three dimension numerical simulations were conducted in the present paper. The swirl flow was assumed in the cylindral calculation domain. The bubble interface was captured by Volume Of Fluid (VOF) method. The properties of saturated water and steam at different pressure were applied in the simulation. The bubble trajectory, motion, shape and force were obtained based on the bubble parameters captured by VOF. The simulation cases in the present study included single bubble with different size, at different angular velocity conditions and at different pressure conditions. The results indicated that bubble migrated to the center in swirl flow with spiral motion type. The lateral migration was mainly related to shear stress magnitude and bubble size. The bubble moved toward the center with high velocity when the swirl magnitude was high. The largest bubble had the highest lateral migration velocity in the present study range. The effect of pressure was small when bubble size was the same. The prelimenery simulation result would be beneficial for better understanding complex two phase flow phenomena in fuel assembly with spacer grid.

• 화약ㆍ발파
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• 제38권4호
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• pp.26-36
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• 2020

지하공간의 이용범위 확장 및 활용이 증가함에 따라 테러리스트들에 의한 지하 내부 폭발의 발생 가능성이 증가하고 있다. 본 연구에서는 심도 50m의 심도에 굴착된 원형 터널을 모델링한 후, 터널의 내부에 폭발하중을 가하였다. 폭발하중은 ATF(Bureau of Alcohol, Tobacco, and Firearms)에서 제시하는 6종류의 운반용 차량에 대한 최대 폭약량의 폭발하중을 산정하였다. 원형 터널 주변 지반은 국내 터널 설계에서 제시하는 지보패턴에 따른 3종류의 암반등급을 선정하였다. 비선형 동적해석을 수행하여 폭발하중과 지반 특성을 매개변수로 지표 변위를 분석하여 지상 구조물의 영향에 대해 평가하였다. 해석결과, 1등급암에 대해서는 지반의 융기에 대한 영향을 고려해야 하며, 2등급암과 3등급암은 부등침하에 대한 영향을 고려해야 한다. 특히, 3등급암은 40m 이내의 지상 구조물에 대해서는 정밀 분석이 요구된다. 또한 지표 변위는 탄성계수에 의한 영향이 주요인인 것으로 판단된다.

• Journal of the Korean Physical Society
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• 제73권11호
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• pp.1764-1773
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• 2018

A-PET is a quad-head PET scanner developed for use in small-animal imaging. The dimensions of its volumetric field of view (FOV) are $46.1{\times}46.1{\times}46.1mm^3$ and the gap between the detector modules has been minimized in order to provide a highly sensitive system. However, such a small FOV together with the quad-head geometry causes image quality degradation. The main factor related to image degradation for the quad-head PET is the mispositioning of events caused by the penetration effect in the detector. In this paper, we propose a precise method for modelling the system at the high spatial resolution of the A-PET using a LOR (line of response) based ML-EM (maximum likelihood expectation maximization) that allows for penetration effects. The proposed system model provides the detection probability of every possible ray-path via crystal sampling methods. For the ray-path sampling, the sub-LORs are defined by connecting the sampling points of the crystal pair. We incorporate the detection probability of each sub-LOR into the model by calculating the penetration effect. For comparison, we used a standard LOR-based model and a Monte Carlo-based modeling approach, and evaluated the reconstructed images using both the National Electrical Manufacturers Association NU 4-2008 standards and the Geant4 Application for Tomographic Emission simulation toolkit (GATE). An average full width at half maximum (FWHM) at different locations of 1.77 mm and 1.79 mm are obtained using the proposed system model and standard LOR system model, which does not include penetration effects, respectively. The standard deviation of the uniform region in the NEMA image quality phantom is 2.14% for the proposed method and 14.3% for the LOR system model, indicating that the proposed model out-performs the standard LOR-based model.

• Biomolecules & Therapeutics
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• 제30권3호
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• pp.232-237
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• 2022

Autism spectrum disorder (ASD) having core characteristics of social interaction problems and repetitive behaviors and interests affects individuals at varying degrees and comorbidities, making it difficult to determine the precise etiology underlying the symptoms. Given its heterogeneity, ASD is difficult to treat and the development of therapeutics is slow due to the scarcity of animal models that are easy to produce and screen with. Based on the theory of excitation/inhibition imbalance in the brain with ASD which involves glutamatergic and/or GABAergic neurotransmission, a pharmacologic agent to modulate these receptors might be a good starting point for modeling. N-methyl-D-aspartic acid (NMDA) is an amino acid derivative acting as a specific agonist at the NMDA receptor and therefore imitates the action of the neurotransmitter glutamate on that receptor. In contrast to glutamate, NMDA selectively binds to and regulates the NMDA receptor, but not other glutamate receptors such as AMPA and kainite receptors. Given this role, we aimed to determine whether NMDA administration could result in autistic-like behavior in adolescent mice. Both male and female mice were treated with saline or NMDA (50 and 75 mg/kg) and were tested on various behavior experiments. Interestingly, acute NMDA-treated mice showed social deficits and repetitive behavior similar to ASD phenotypes. These results support the excitation/inhibition imbalance theory of ASD and that NMDA injection can be used as a pharmacologic model of ASD-like behaviors.

• Nuclear Engineering and Technology
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• 제54권2호
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• pp.589-600
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• 2022

Investigations on the molten-pool sloshing behavior are of essential value for improving nuclear safety evaluation of Core Disruptive Accidents (CDA) that would be possibly encountered for Sodium-cooled Fast Reactors (SFR). This paper is aimed at synthesizing the knowledge from our recent studies on molten-pool sloshing behavior with solid particles conducted at the Sun Yat-sen University. To better visualize and clarify the mechanism and characteristics of sloshing induced by local Fuel-Coolant Interaction (FCI), experiments were performed with various parameters by injecting nitrogen gas into a 2-dimensional liquid pool with accumulated solid particles. It was confirmed that under different particle-bed conditions, three representative flow regimes (i.e. the bubble-impulsion dominant, transitional and bed-inertia dominant regimes) are identifiable. Aimed at predicting the regime transitions during sloshing process, a predictive empirical model along with a regime map was proposed on the basis of experiments using single-sized spherical solid particles, and then was extended for covering more complex particle conditions (e.g. non-spherical, mixed-sized and mixed-density spherical particle conditions). To obtain more comprehensive understandings and verify the applicability and reliability of the predictive model under more realistic conditions (e.g. large-scale 3-dimensional condition), further experimental and modeling studies are also being prepared under other more complicated actual conditions.

• 문화기술의 융합
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• 제8권4호
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• pp.469-476
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• 2022

3D 모델링 기술과 대화 인공지능 알고리즘의 발달로 인해 다양한 분야에서 디지털 휴먼이 활용되고 있고, 신한 은행, 농협 은행 등 주요 은행을 중심으로 은행에서도 가상 은행원이 등장하기 시작했다. 그러나 디지털 휴먼과 관련된 연구는 주로 외형 위주이며, 로봇 의인화 과정에서 고려되어야 하는 퍼소나 설정에 대한 연구는 미비하다. 본 연구에서는 은행 업무라는 구체적인 맥락에서 발화 전략의 의인화 수준과 개인정보 활용 수준이 다른 3가지 시나리오(학생증 수령, 입출금 통장 개설, 전세 자금 대출 상담)에 대한 사용자 경험을 알아보기 위해 실험을 진행하였다. 연구 결과, 사회적 실재감과 유용성은 시나리오와 의인화 수준에 대해 상호작용 효과가 있었다. 친밀감, 신뢰도, 인지된 지능에는 상호작용 효과가 없었지만 경향성을 확인 할 수 있었다.