• 한국융합학회논문지
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• 제12권12호
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• pp.245-255
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• 2021

본 연구는 위챗 소셜미디어 플랫폼의 사회적, 오락적 요인이 이용자의 몰입과 중독에 어떤 영향을 주는지에 대한 실증 연구이다. 연구자들은 소셜미디어 위챗 이용자들의 중독이 늘어나고 있음에도 불구하고, 기존 소셜미디어 연구가 서비스 품질과 만족도 등에 그치고 있어 이용자의 몰입, 중독에 관한 연구가 필요할 것으로 보았다. 따라서 연구자들은 실증분석을 통하여 위챗 사용의 중독에 이르는 경로를 사회적 요인(사교성, 지불성)과 오락적 요인(오락성, 생활 관련성)으로 설정하고 위챗 이용자 체험이 사용 의도와 만족에 어떻게 영향을 미치는지 고찰하고 이용자의 위챗 몰입과 중독으로 이어지는 경로를 확인하고자 하였다. 연구결과 위챗의 사교성 등 기능적 요인이 인지된 용이성 및 유용성에 영향을 주고, 이에 대한 사용과 만족이후 몰입과 중독에 영향을 주는 것으로 검정되었다. 본 연구의 결과는 향후 소셜미디어의 중독적 사용관련 연구에 새로운 이론적 기반이 될 것으로 기대하고 있다.

• 설비공학논문집
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• 제16권1호
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• pp.8-15
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• 2004

Since the vehicle is regarded as the third living space, the comfortable conditions are required in the passenger compartment. For this reason, customers are concerned about the filtering performances and the importance of filter media has been greatly placed. Therefore the dust holding capacity, the efficiency of these filter media (dry paper, wet paper, non-woven) and the configuration of air filter for vehicle were measured in this study. The following results were obtained on the basis of air filter test. It shows that the thickness and poresize of filter media should be lower for the higher efficiency. The measurement result shows that the performance of round shape filters are higher than the square shape filters. The dust holding capacity of the wet paper and the non-woven paper is higher than the dry paper. As a result, this research can provide an important design parameter and product guidance of the intake air filter for vehicular engine.

• 천문학회보
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• 제35권1호
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• pp.67.1-67.1
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• 2010

Understanding the nature of MHD turbulence is of fundamental importance in astrophysics. The results of these studies can be used to develop the star formation theory. While most of previous studies have considered turbulence in uniform media, the stratification of media can play an important role. We performed three-dimensional numerical simulations of isothermal, compressible, MHD turbulence with different plasma beta's and different flow Mach numbers in stratified media to study the effects of stratification on turbulence. We found Statistics of turbulent flow in stratified media is different from in uniform media. In this talk, we present the statistical properties of the MHD turbulence, such as the PDF, power spectrum, and structure function.

• 한국분무공학회지
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• 제24권3호
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• pp.122-129
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• 2019

Flow uniformity in aftertreatment system is an important factor in determining uniform catalytic reaction and filtration. In this study, variety types of DOC-DPF system design were analyzed to increase flow uniformity. For this analysis, ANSYS Fluent was used with porous media setup for DOC and DPF. Turbulent flow was modeled by standard $k-{\varepsilon}$ model excepting porous media. Uniformity index was utilized to evaluate the flow uniformity quantitatively. Reference design showed low velocity region because two large vortex were generated before baffle. When radius of DOC-DPF system was increased, exhaust pressure acting on the inlet decreases and velocity distribution was shifted to one side. When inlet pipe was set to axial center of DOC-DPF system velocity distribution was symmetric. However, flow was not dissipated until the front end of DOC and showed higher uniformity index. When the volume of DOC was reduced while fixed volume of entire DOC-DPF system and baffle plate is located downstream of the DOC-DPF system, there was improvement in uniformity index.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제20권3호
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• pp.243-259
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• 2016

The Richards equation for water movement in unsaturated soil is highly nonlinear partial differential equations which are not solvable analytically unless unrealistic and oversimplifying assumptions are made regarding the attributes, dynamics, and properties of the physical systems. Therefore, conventionally, numerical solutions are the only feasible procedures to model flow in partially saturated porous media. The standard Finite element numerical technique is usually coupled with an Euler time discretizations scheme. Except for the fully explicit forward method, any other Euler time-marching algorithm generates nonlinear algebraic equations which should be solved using iterative procedures such as Newton and Picard iterations. In this study, lumped mass and distributed mass in the frame of Picard and Newton iterative techniques were evaluated to determine the most efficient method to solve the Richards equation with finite element model. The accuracy and computational efficiency of the scheme and of the Picard and Newton models are assessed for three test problems simulating one-dimensional flow processes in unsaturated porous media. Results demonstrated that, the conventional mass distributed finite element method suffers from numerical oscillations at the wetting front, especially for very dry initial conditions. Even though small mesh sizes are applied for all the test problems, it is shown that the traditional mass-distributed scheme can still generate an incorrect response due to the highly nonlinear properties of water flow in unsaturated soil and cause numerical oscillation. On the other hand, non oscillatory solutions are obtained and non-physics solutions for these problems are evaded by using the mass-lumped finite element method.

• 드라이브 ㆍ 컨트롤
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• 제19권1호
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• pp.62-68
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• 2022

Considering the characteristics of industrial machines that lack vehicle-induced wind, forced convection by a cooling fan is mostly required. Therefore, numerical analysis of an engine room is usually performed to examine the cooling performance in the room. However, most engine rooms consist of a number of parts and components at specific positions, leading to high costs for numerical modeling and simulation. In this paper, a new methodology for three-dimensional computer-assisted design simplification was proposed, especially for the pile of components and parts at the engine room outlet. A porous media model and regression analysis were used to derive a meta-model for imitating the flow rate reduction at the outlet by the pile. The results showed that the fitted model was reasonable considering the coefficient of determination. The final numerical model of the engine room was then used to simulate the velocity distribution by changing the mass flow rate at the outlet. The results showed that both velocity distributions were significantly changed in each case and the meta-model was valid in imitating the flow rate reduction by some piles of components and parts.

• 디지털융복합연구
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• 제16권4호
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• pp.313-319
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• 2018

본 연구는 최근 방송, 영화 등에 활발하게 사용되고 있는 드론의 무빙 영상이 수용자의 몰입도와 흥미 유발, 감정상태 등에 미치는 영향을 살펴본 실험 연구이다. 그동안 미디어 영상 효과 연구들은 영상의 움직임이 스토리 자체에 내재되어 있는 느낌을 주기 위해서 카메라의 움직임을 자제하는 것이 좋으며, 카메라의 움직임이 오히려 수용자의 자연스러운 시청에 방해가 될 수 있다고 주장하고 있다. 본 연구에서는 드론의 움직이는 영상이 시청자의 몰입도, 흥미 유발, 감정 상태 등에 어떤 영향을 미치는지 알아보기 위해서, 대학생들을 두 그룹으로 나누고, 한 그룹의 피실험자들에게는 무빙 중심으로 편집된 드론 영상물을 보여주고, 다른 한 그룹의 피실험자들에게는 호버링 중심으로 편집된 드론 영상물을 각각 보여준 다음, 설문조사를 통해 이들이 느낀 몰입도, 흥미도, 감정상태 등을 측정하고, 측정한 결과를 변량 분석하였다. 분석 결과, 드론의 움직임이 있는 영상물을 감상한 피실험자들은 드론의 움직임이 없는 영상물을 감상한 피실험자들에 비해, 흥미를 더 많이 느끼고, 긍정적인 감정상태를 더 많이 느낀것으로 나타났다. 그러나 드론의 무빙과 피실험자들의 몰입도 간에는 서로 관련이 없는 것으로 나타났다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집B
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• pp.241-246
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• 2000

Gas hydrates are solid solutions when water molecules are linked through hydrogen bondin create host lattice cavities that can enclose a large variety of guest gas molecules. The natural hydrate crystal may exist at low temperature above the normal freezing point of water and pressure greater than about 30 bars. A lot of quantities of natural gas hydrates exists in the ear many production schemes are being studied. In the present investigation, depressurization method considered to predict the production of gas and the simulation of the two phase flow - gas and - in porous media is being carried out. The simulation show about the fluid flow in porous have a variety of applications in industry. Results provide the appearance of gas and water prod the pressure profile, the saturation of gas/ water/ hydrates profiles and the location of the pl front.

• 대한기계학회논문집B
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• 제21권12호
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• pp.1668-1678
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• 1997

Numerical analyses were performed to investigate the characteristics of regenerator in oscillating flow by using moving boundary method and Darcy model. In this work, periodic adiabatic boundary condition was suggested as the boundary condition of adiabatic part so that the effects of the thermal inertia of the wall could be considered. In carrying out numerical analyses, two models were applied and compared. One called isotropic model has the same thermal conductivity in radial and axial directions within a porous media. The other called aeolotropic model has different conductivity in each directions. Isotropic model could not show the advantage of energy reduction which needs to maintain constant wall temperature difference between heater and cooler. But aeolotropic model could simulate the reduction of energy consumption.

• 화훼연구
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• 제16권3호
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• pp.205-210
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• 2008

본 연구는 ebb & flow 방식에서 기린초를 분화재배할 때 적당한 배지를 선발하기 위한 것으로서 분화용 양액 (Sonneveld액)을 관주한 후 생육과 양분흡수특성을 분석하였다. 피트모스와 펄라이트를 5:5 또는 7:3(v/v)으로 혼합한 배지는 코이어와 펄라이트를 동일한 비율로 혼합한 상토보다 가비중과 건물함량은 높았지만 수분함량은 낮았고 그 밖의 물리적 특성은 차이가 없었다. 피트모스 혼합 배지는 코이어 혼합 배지보다 pH는 낮고(5.4) EC는 높으며 ($0.3dS{\cdot}m^{-1}$), $NH_4-N$, $NO_3-N$, K, Ca의 함량이 많아서 기린초의 초장, 엽장, 분지수 등의 생육이 촉진되었다. 반면 코이어 혼합 배지는 양분함량, 특히 질소 함량이 낮아서 배양액을 공급하더라도 생육이 저조하였다. 그러므로 기린초의 분회용 배지는 피트모스와 펄라이트를 혼합한 것이 좋으며 최적 혼합 비율은 7:3과 5:5(v/v)가 모두 적당한 것으로 판단되었다.