• 한국콘텐츠학회논문지
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• 제15권2호
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• pp.507-519
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• 2015

본 연구에서는 스마트폰, 태블릿 PC를 활용한 스마트러닝 환경에서 기기의 유형 및 모달리티(modality)가 학습자의 주관적인 상호작용경험에 미치는 영향을 실험연구를 통해 검증하였다. 분석 결과, 모달리티는 사회적 실재감 및 학습자의 상호작용경험(상호작용경험 평가, 다른 학습자에 대한 태도)에 유의미하게 긍정적인 영향을 미치는 것으로 나타났다. 스마트 기기 유형의 경우 사회적 실재감 및 학습자의 상호작용경험에 직접적으로 미치는 영향은 없었으나, 모달리티가 사회적 실재감 및 학습자의 상호작용경험에 영향을 미칠 때 조절변인으로서 상호작용효과를 가지는 것으로 나타났다. 이러한 연구 결과는 다양한 기기를 활용한 스마트러닝 환경에서 사회적 실재감 및 학습자 간 상호작용을 증진시킬 수 있는 학습 환경의 설계 원리를 제시한다는 측면에서 시사점을 가진다.

• 대한조선학회논문집
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• 제50권1호
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• pp.33-40
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• 2013

Since most of yacht sails are made of thin fabric, they form cambered sail shape that can efficiently generate lift power by aerodynamic interaction and by external force delivered from supporting structures such as mast and boom. When the incident flow and external force alter in terms of volume or condition, the shape of sail also change. This deformation in shape has impact on the peripheral flow and aerodynamic interaction of the sail, and thus it is related to the deformation of the sail in shape again. Therefore, the precise optimization of aerodynamic performance of sail requires fluid-structure interaction (FSI) analysis. In this study, the simplified sail without camber was under experiment for one-way FSI that uses the result of flow analysis to the structural analysis as load condition in an attempt to fluid-structure interaction phenomenon. To confirm the validity of the analytical methods and the reliability of numerical computation, the difference in deformation by the number of finite element was compared. This study reproduced the boundary conditions that sail could have by rigs such as mast and boom and looked into the deformation of sail. Sail has non-linear deformation such as wrinkles because it is made of a thin fabric material. Thus non-linear structural analysis was conducted and the results were compared with those of analysis on elastic material.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집A
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• pp.465-470
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• 2001

In this study, the seismic analysis of rack structure with fluid-structure interaction is performed through use of the Finite Element Method(FEM) code ANSYS. Fluid-structure interaction can specify in terms of an hydrodynamic effect which is defined as the added mass per unit length divided by the area of the cross section. Using the Floor Response Spectrum(FRS) obtained through the time-history analysis, modal analysis and seismic analysis under Operating Basis Earthquake(OBE) and Safe Shutdown Earthquake(SSE) condition is carried out. The fluid-structure interaction effects on the rack structure are investigated.

• Journal of Radiation Protection and Research
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• 제36권1호
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• pp.1-7
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• 2011

A simple mathematical model of simultaneous combined action of environmental agents has been proposed to describe the synergistic interaction of microwave and high ambient temperature treatment on animal heating. The model suggests that the synergism is caused by the additional effective damage arising from an interaction of sublesions induced by each agent. These sublesions are considered to be ineffective if each agent is taken individually. The additional damage results in a higher body temperature increment when compared with that expected for an independent action of each agent. The model was adjusted to describe the synergistic interaction, to determine its greatest value and the condition under which it can be achieved. The prediction of the model was shown to be consistent with experimental data on rabbit heating. The model appears to be appropriate and the conclusions are valid.

• Journal of the Korean Wood Science and Technology
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• 제27권3호
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• pp.73-81
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• 1999

가장 보편적으로 사용되고 있는 도공용 안료인 클레이와 탄산칼슘의 배합비율을 실제 도공공정의 안료 혼합비와 근사하게 설정한 후, 이온성 라텍스를 적용해 봄으로서 이들의 상호작용과 도공지의 품질에 미치는 영향에 대해 검토해 보았다. 1,2급 클레이를 각각 35부, 탄산칼슘을 30부씩 혼합한 후, 제조한 도공액의 탈수량 및 침강중량비 측정 결과, 양성라텍스는 음이온성 라텍스보다 다분산 안료 배합하에서도 안료와의 상호작용이 크다는 것을 알 수 있었으며, 형성된 필터케이크충의 구조가 다공성임을 알 수 있었다. 이러한 결과는 제조한 도공지의 표면거칠기 및 투기도 등의 도공지 표면 및 내부육특성 측정을 통해 확인할 수 있었다. 결과적으로 양성라텍스를 사용하여 제조한 도공지의 인쇄적 성이 음이온성 라텍스를 사용한 경우보다 우수하였다. 이는 양성라텍스가 탄산칼슘이 일정비율 첨가된 안료 배합조건 하에서도 이오기의 전하반전 특성을 통해 클레이와의 정전기적 상호작용을 할 수 있다는 사실을 보여주었으며, 1급 클레이의 혼합비율 일부를 2급 및 탄산칼슘으로 대체하여 도공지의 품질 및 인쇄적성을 개량하였다.

• 한국연소학회지
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• 제17권3호
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• pp.1-8
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• 2012

The CO emission characteristics of interacting hydrogen and methane partially premixed flames were numerically investigated. A counterflow geometry was introduced to establish interacting two partially premixed flames. An one-dimensional OPPDIF code was used to simulate the interacting flames. The GRI-v3.0 was used to calculate the chemical reactions. Emission index for CO(EICO) was evaluated to quantify the CO emitted from the interacting flames. The global strain rate and equivalence ratios for each flame(${\Phi}_{CH_4}$ and ${\Phi}_{H_2}$) were used as parameters to control the extent of interaction between two partially premixed flames. When ${\Phi}_{CH_4}$ was kept to stoichiometric condition and ${\Phi}_{H_2}$ was at rich condition, unburned H2 species of hydrogen flame was transported to the methane flame and affected reactions related with CO formation. When ${\Phi}_{CH_4}$ increased from a stoichiometry to rich condition while ${\Phi}_{H_2}$ was kept to stoichiometric condition, EICO increased initially, had a peak value at ${\Phi}_{CH_4}=1.5$ and decreased gradually. This could be elucidated with an analysis for the elementary reactions related with CO formation.

• Geomechanics and Engineering
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• 제24권5호
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• pp.443-456
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• 2021

Structural design of the vertical displacements and shear strains in the earth fill (EF) dams has great importance in the structural engineering problems. Moreover, far fault earthquakes have significant seismic effects on seismic damage performance of EF dams like the near fault earthquakes. For this reason, three dimensional (3D) earthquake damage performance of Oroville dam is assessed considering different far-fault ground motions in this study. Oroville Dam was built in United States of America-California and its height is 234.7 m (770 ft.). 3D model of Oroville dam is modelled using FLAC3D software based on finite difference approach. In order to represent interaction condition between discrete surfaces, special interface elements are used between dam body and foundation. Non-reflecting seismic boundary conditions (free field and quiet) are defined to the main surfaces of the dam for the nonlinear seismic analyses. 6 different far-fault ground motions are taken into account for the full reservoir condition of Oroville dam. According to nonlinear seismic analysis results, the effects of far-fault ground motions on the nonlinear seismic settlement and shear strain behaviour of Oroville EF dam are determined and evaluated in detail. It is clearly seen that far-fault earthquakes have very significant seismic effects on the settlement-shear strain behaviour of EF dams and these earthquakes create vital important seismic damages on the swelling behaviour of dam body surface. Moreover, it is proposed that far-fault ground motions should not be ignored while modelling EF dams.

• 유통과학연구
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• 제18권1호
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• pp.95-105
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• 2020

Purpose: Will more expensive gifts be more pleasurable and appreciated? This is a general expectation of gift-givers. According to the previous study on Americans (Flynn and Adams 2009), recipients tend to appreciate gifts regardless of their price. It indicates that there is an interaction effect between position (giving / receiving) and gift price. This study expands the previous study and aims to answer the following two questions: "Are such an interaction effect observed in Korean, too?" and "What types of people prefer expensive gifts?" Research design, data, and methodology: Study 1 of the current research repeated the Study 3 of Flynn and Adams (2009), with an iPod (high-priced gift condition) and a music CD (low-priced gift condition). That is, a 2 (gift price: high / low) x 2 (position: giver / receiver) between-group design was used. Study 2 used gift certificates of 100,000 won (high-priced gift condition) and 5,000-won gift (low-priced gift condition). Unlike the previous study that measured only one dependent variable (gratitude), this study added five more dependent variables in an attempt to exclude alternative explanations, such as endowment effects or emotional conflicts. This study also measured individualism / collectivism, face sensitivity, and materialism to explore the types of people who prefer expensive gifts. Results: The interaction effect between gift price and position on the level of appreciation was not significant. Meanwhile the main effect of gift price and of position were significant. The gift-recipient was more appreciative than the gift-givers' expectation regardless of the price of gifts. To investigate individual differences, individualism/collectivism, face sensitivity, and materialism were examined, but none of these variables were significantly related to the preference for expensive gifts. Respondents who received gift certificates in Study 2 were less grateful than those who received iPods or music CDs in Study 1. Conclusions: This study found that Koreans tend to be more grateful if they receive expensive gifts, in contrast to the Flynn and Adams (2009)'s study with Americans. In addition, gift-recipients appreciated more than givers' expectation and were more grateful when they received tangible products rather than gift certificates.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2004년도 제22회 춘계학술대회논문집
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• pp.699-702
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• 2004

In this study, the affect of mounting axisymmetrical supersonic inlet to airfoil, which has 65 degree swept angle was numerically investigated. The parameter for this calculation are tree stream Mach number M=2.0 and 2.5, the distance between inlet spike and airfoil lower surface $L_{sw}$/$R_{cowl}$ = 1.21-1.54 and angle of attack to the airfoil 0-4. The mass capture ratio improved 3points in M=2.0 condition and 1points in M=2.5 while the mass capture ratio without airfoil surface was 57% and 71 % for each case. These are the result from increase of density and change of velocity deflection by the shock wave structure formed between inlet and airfoil surface. On the other hand, the distortion of Mach number at cowl lip plane increased by 13% in M=2.0, 3% in M=2.5 condition. The effects of the angle attack on the mass capture ratio is greater than that of the shock wave interaction between inlet and cowl, but the effects to the distortion is smaller in the range of this calculation condition. In the condition of M=2.0 with 4 degrees of angle of attack, inlet distortion of Mach number is mainly caused by the affects of the shock wave interaction between inlet and airfoil surface, while the largest angle of the velocity vector in the radial direction at cowl lip plane is caused by the affect of angle of attack. This large velocity vector made the flow inside the cowl subsonic and caused spillage, which interfere with the boundary layer of airfoil surface.

• Korea-Australia Rheology Journal
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• 제19권4호
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• pp.233-242
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• 2007

We performed a numerical investigation to find out the optimal choice of the spatial discretization in the distributed-Lagrangian-multiplier/fictitious-domain (DLM/FD) method for the solid/fluid interaction problem. The elastic solid bar attached on the bottom in a pressure-driven channel flow of a Newtonian fluid was selected as a model problem. Our formulation is based on the scheme of Yu (2005) for the interaction between flexible bodies and fluid. A fixed regular rectangular discretization was applied for the description of solid and fluid domain by using the fictitious domain concept. The hydrodynamic interaction between solid and fluid was treated implicitly by the distributed Lagrangian multiplier method. Considering a simplified problem of the Stokes flow and the linearized elasticity, two numerical factors were investigated to clarify their effects and to find the optimum condition: the distribution of Lagrangian multipliers and the solid/fluid interfacial condition. The robustness of this method was verified through the mesh convergence and a pseudo-time step test. We found that the fluid stress in a fictitious solid domain can be neglected and that the Lagrangian multipliers are better to be applied on the entire solid domain. These results will be used to extend our study to systems of elastic particle in the Stokes flow, and of particles in the viscoelastic fluid.