• Proceedings of the Korean Geotechical Society Conference
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• 1991.10a
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• pp.235-254
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• 1991

In the analysis of seepage behavior through the porous media, unsaturated domain should be included for obtaining more accurate results. The seepage programs considering its domain have been developed and practically used widely. The programs are reviewed and two case studies are presented in this paper. The case studies are performed using PC-SEEP and obtained good results for the cases of saturated-unsaturated transient flow.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2005.10a
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• pp.101-103
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• 2005

• Proceedings of the Korea Information Processing Society Conference
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• 2016.04a
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• pp.526-528
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• 2016

EPDW는 Event-Process-Data-Work의 약자로 소프트웨어 아키텍처이다. 이 아키텍처는 Event 지향적인 프로그래밍 아키텍처이다. Event 가 발생하면 Process에서 가공하고 Data로 만들어 Work가 처리하는 기본구조를 가지고 있다. 모든 Event는 EventDivider 흐름이 관리되며 Process는 EventDivider에 등록된다. Work는 하나의 기능단위로써 필요한 controller들과 Process들을 가진다. 이를 통해 Event 가공의 코드의 재사용 및 분산방지가 된다. 그리고 Event 흐름의 단순화와 추적의 용이성을 증대해 디버깅에 이점을 가진다.

• Journal of the Korea Computer Graphics Society
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• v.28 no.3
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• pp.79-89
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• 2022

With the popularity and the advanced graphics hardware technology of mobile devices, various mobile applications that help children with physical activities have been studied. This paper presents SandUp, a mobile application that guides the play of building sand castles using artificial intelligence and augmented reality(AR) technology. In the process of building the sandcastle, children can interactively explore the target virtual sandcastle through the smartphone display using AR technology. In addition, to help children complete the sandcastle, SandUp informs the sand shape and task required step by step and provides visual and auditory feedback while recognizing progress in real-time using the phone's camera and deep learning classification. We prototyped our SandUp app using Flutter and TensorFlow Lite. To evaluate the usability and effectiveness of the proposed SandUp, we conducted a questionnaire survey on 50 adults and a user study on 20 children aged 4~7 years. The survey results showed that SandUp effectively helps build the sandcastle with proper interactive guidance. Based on the results from the user study on children and feedback from their parents, we also derived usability issues that can be further improved and suggested future research directions.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.3173-3177
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• 2007

Recently, we have many problems on the process of the sludge. In past, the sewage sludge was treated by reclaimed land or thrown away in the sea. But these methods caused environmental pollution. Today, many researchers are studying various methods for reducing its volume. One of these method, this study is to reduce the moisture of sewage sludge and to solidify it using a dryer and curing equipment. In this research, we investigated about design parameter and operation condition of the equipment. The curing equipment reduces the percentage of water content from 30% of dryer to 10%. So, we have to study the curing characteristics and performance of curing equipment. For example, there are internal flow characteristics and change of the percentage of water content. And we investigated the change of data at outlet along the initial condition, temperature, humidity and air flow. Using this data, we achieve the experimental results of curing efficiency by each geometry and operating condition. And we also investigated numerical analysis of internal flow using CFD code. This research is basic study for optimal design of the curing equipment.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• v.y2005m4
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• pp.35-38
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• 2005

The computational fluid dynamic analysis has been conducted for the thermo-chemical flow field in an arcjet thruster with mono-propellant hydrazine ($N_{2}H_4$) as a working fluid. Coupled Reynolds Averaged Navier-Stokes (RANS) equations and Maxwell equations were used to account for the Ohm heating and Lorentz forces. Hydrazine chemistry and thermal radiation were also incorporated to the fluid dynamic equations by assuming infinitely-fast reactions and optically thick media. In addition to the thermo-physical understandings of the flow field inside the arcjet thruster, results shows that performance indices are improved by amount of $20\%$ in thrust and $200\%$ in specific impulse with the 0.6kW are heating.

• Journal of Korea Soil Environment Society
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• v.5 no.3
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• pp.35-54
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• 2001

It is difficult to accurately predict each flow rate of landfill gas and leachate extracted from many of wells, which have been completed into a waste landfill containing gas and water. However it may be approximately predicted if we can define only relative fluid permeability of gas and leachate flowing through landfill porous media. Therefore numerical simulation using multi-phase flow equations makes use of ei s input data of the relative permeability which is measured and calculated in laboratory environment like in-situ, and consequently we can quantitatively obtain each flow rate of gas and leachate from collection wells. These series of technologies can provide with the important informations to determine the success or failure of landfill gas energy and landfill stabilization. This paper analyses the characteristics of landfill gas collection by six classes of case studies for none described landfill.

• Journal of the Korean Home Economics Association
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• v.47 no.2
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• pp.81-95
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• 2009

The purpose of this study is to examine gender equity in the quantity and flow experience of leisure time of urban dual-earner couples having preschool children. The quantity of leisure time is measured by primary activity and the flow experience of leisure time is measured by primary and secondary activities. The data collected by Korean National Statistical Office in 2004 is used. The sample for this study consists of 255 couples, and the statistical methods are frequency, percentage, paired t-test, and one-way ANOVA. The following is a summary of the major findings. The first, the pattern of the leisure time was different between husbands and wives. The quantity of leisure time of husbands was longer than that of wives. The husbands spent more time to perform social activities, media contact, sports and outdoor activities, while women did more in religious activities. The second, husband's leisure flow experience was higher than that of wives. The pure leisure time of wives was shorter than that of husbands and wives experienced more contaminated leisure time by a secondary activity. In other words, wives's leisure is more likely to be interrupted, to involve episodes of shorter duration, and to be associated with personal care and unpaid work.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2005.11a
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• pp.132-135
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• 2005

The computational fluid dynamic analysis has been conducted for the thermo-chemical flow field in an arcjet thruster with mono-propellant hydrazine $(N_2H_4)$ as a working fluid. Coupled Reynolds Averaged Navier-Stokes (RANS) equations and Maxwell equations were used to account for the Ohm heating and Lorentz forces. ionization and thermal radiation effects were also incorporated to the fluid dynamic equations by assuming infinitely-fast reactions and optically thick media. In addition to the thermo-physical understandings of the flow field inside the arcjet thruster, results shows that performance indices are improved by amount of 20% in thrust and 70% in specific impulse with the 0.6kW are heating.

• Journal of Korean Society for Atmospheric Environment
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• v.15 no.6
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• pp.799-804
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• 1999

Particle collection characteristics of the MOUDI cascade impactor has been studied for coarse particles in the range of 2 to 20$mu extrm{m}$ in aerodynamic diameter. A vibrating orifice aerosol generator was empolyed to generate monodisperse test aerosols. The oleic acid and sodium chloride(NaCl) particles were used as test aerosols. Aluminum foil and Teflon filter were selected as impaction media. The sampling flow rate was changed from 25 to 35L/min. Particle collection efficiency for single stage was examined for liquid particles. The stage response was obtained experimentally for the cascade impactor composed of three stages and a backup filter. The results showed that most of particle collection efficiencies measured in this work are similar to the efficiency curves obtained by Marple et al.(1991). For particles less than cut-off size of the stage, the collection efficiencies of solid particles are similar to those of loquid particles. However, the collection efficiency of solid particles decreases with mereasing particle diameter for the particles greater than the actual cut-off size of the impactor. The particle collection efficiency increases with increasing sampling flow rate at the same particel size. However, the collection efficiency curves seem not to be greatly shifted with the flow rate. The stage responses obtained by direct measurements in this work are in good agreement with those derived from the collection efficiency curves for single stage.