• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.911-920
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• 2010

A closed-type erosion control dam were suggested as an effective method to protect from debris flow damages caused by seasonal rainstorm, typhoon, and local heavy rain. However, design method on a closed-type erosion control dam currently practiced in the engineering is not well established with respect to type of the dam, design parameters, maintenance and so forth. In this study, design parameters for closed-type erosion control dam were evaluated and the comparison of design parameters used in Korea and Japan was performed. Based on the results of this study, modification of design method for closed-type erosion control dam are recommended.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.9
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• pp.934-942
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• 2007

In this study, the characteristics of the load-sensitive hydraulic control system for closed center type of a wheel loader were analyzed using developed analysis program based on Amesim tool. From the parametric analysis, the effects of each factor were revealed. Through the simulation with varying parameters, the system parameter effects on the controllable region and the pump pressure and load pressure variations were studied. The results were compared with the experimental ones. The results and discussions of the present paper could aid in the design of a load-sensitive hydraulic control system for closed center type.

• 제어로봇시스템학회:학술대회논문집
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• 1987.10b
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• pp.364-369
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• 1987

It has recently shown that a solenoid valve can be utilized in a hydraulic position-control system by discontinuous control methods. The objective of this study is to investigate the effects of solenoid valves on the response characteristics of a hydraulic position-control system by applying two kinds of discontinued control methods i.e., Simple On-Off (SOF) and Pusating On-Off(POF) controls. Three types of solenoid valves i.e. low-frequency, closed-center type (LF/C), high-frequency, closed-center type (HF/C), low-frequency, tandem-center type(LF/T) were used in this study. Effects of loading conditions and control parameters on the response characteristics were experimentally examined and compared each other. Pressure transients within the actuator were also studied.

• Journal of the Economic Geographical Society of Korea
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• v.23 no.4
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• pp.408-424
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• 2020

This study attempts to analyze the spatial clustering of survived and closed coffee shops based on the land price and land use for each coffee shop location. The locational characteristics of survived and closed coffee shops for each cluster type are identified through various locational properties such as transport factors (physical accessibility), shop properties (franchise information, newly open/closed business experience), and spatial density (kernel density estimation). To this end, we categorize the clusters of survived and closed coffee shops into three types (general locational distribution type, commercialization type of residential area and location type of commercial center), and then analyze their locational characteristics. As the result, we found that the locations of newly open and closed coffee shops show different distribution characteristics, even though they are classified into the same type due to the double sidedness of new open and closed locations. The results of this study can be provided as basic data for planning the location of coffee shop as well as regional commercial district.

• Transactions on Electrical and Electronic Materials
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• v.11 no.4
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• pp.178-181
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• 2010

An automotive IC voltage regulator which consists of one-chip based on a metal-oxide semiconductor field effect transistor (MOSFET) is investigated experimentally with three types of packaging. The closed type is filled with thermal silicone gel and covered with a plastic lid on the MOSFET. The half-closed type is covered with a plastic case but without thermal silicone gel on the MOSFET. Opened type is no lid without thermal silicone gel. In order to simulate the high temperature condition in engine bay, the operating circuit of the MOSFET is constructed and the surrounding temperature is maintained at $100^{\circ}C$. In the overshoot the maximum was mainly found at the half-closed packaging and the magnitude is dependent on the packaging type and the surrounding temperature. Also the impressed current decreased exponentially during the MOSFET operation.

• 한국초전도학회:학술대회논문집
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• v.15
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• pp.95-95
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• 2005

• Journal of ILASS-Korea
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• v.28 no.2
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• pp.75-88
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• 2023

In this paper, the atomization characteristics of bi-swirl coaxial injectors for a 420 N-class bipropellant thruster were investigated. Three types of injectors, namely closed-type, open-type, and screw-type, were manufactured and designed to have the same spray angle and injection pressure drop. Water was used as a simulant, and cold-flow tests were conducted under ambient temperature and pressure conditions. Since the inner and outer injectors were designed to be the same type, only the inner fuel injectors that were easy to measure were used. Using a phase doppler particle analyzer, the velocity and diameter of atomized droplets were measured. Closed-type swirl injector exhibited droplet distributions with relatively high velocities and small SMD compared to the other two injectors. Open-type swirl injector formed droplets with reverse velocities in the center region and had a large recirculation zone. Screw-type swirl injector showed a sharp decrease in droplet velocity and size with radial distance from the liquid film breakup point. For the same design requirements, the closed-type swirl injector has superior atomization performance.

• Korean Institute of Interior Design Journal
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• no.20
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• pp.91-97
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• 1999

Telecommuting becomes a new form of work according to the development of information technology. Therefore, the purpose of this study is to provide basic data for the interior space planning of telecommuting centers by means of surveying office workers' opinions. The major findings of this research are as follows. The opinion about whether to use telecommuting center if provided is showed highly positively. In the matter of space type of telecommuting center, 'mixing type I (open plan office but division with high partition)' is the most preferred, the next, is 'closed type'. The most preferred type of workstation is 'independent type', the next is 'X type' and the third is 'link type'. Preferred partition height is '1,300-1,500mm'. When planning telecommuting center, the most important element of space plan is 'size and layout of workstation' and the second is 'private space for confidential work'. In public workplace, the most important element 'refreshment space', and the second one is 'mailing system'.

• Journal of the Korean Solar Energy Society
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• v.32 no.3
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• pp.114-122
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• 2012

Vertical closed-loop ground source heat pump systems(GSHP) have been installed widely in Korea since it can extract moderate temperature level of geothermal heat in a small area. As a ground heat exchanger, a vertical closed -loop type with brine circulation is mostly preferred since it is simple and less harmful to ground environment. However, it requires a secondary heat exchange loop between the refrigerant in a heat pump and the brine. By adding a geothermal heat exchanger in the secondary heat exchange loop, circulation pumps should be attached and the temperature difference between refrigerant and ground is increased, which are important parts of performance degradation. In this paper, annual and seasonal performances of direct expansion(DX) geothermal heat pump were estimated mathematically as an alternative of classical indirect geothermal heat pump based on the annual performance evaluation. As results, DX geothermal heat pump showed 43% higher annual performance than the classical U-tube geothermal heat pump.

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.357-359
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• 1999

It is necessary for the optimum design of switching devices to calculate repulsion forces acting on the closed electric contacts flowing over-current, e.g. inrush current and overload currents. In this paper, the forces generated by currents and flux densities at the contact point when circuit breakers are in closed position are obtained by using 3D finite element method. According to the analysis, the optimum configuration of wipe springs and arc extinguishing chambers are newly designed and consequently type tests show satisfactory results.