• Proceedings of the KSME Conference
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• 2004.11a
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• pp.504-509
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• 2004

Chemical machining(CHM) is a special process which material removed by contact of strong etchant. The application as industrial process was started from aircraft industry after 2nd world war. Chemical milling, one of the CHM process, initially became commercial bussiness and it was called chem-mill. Even today, this process widely used to remove the material from aircraft wings and fuselage panel in aircraft industry. In this study, it is attempted to design the cylinder pattern which minimize the weight within the allowable stress using chemical milling.

• Journal of Sensor Science and Technology
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• v.19 no.2
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• pp.92-98
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• 2010

The capacitive sensor has a simple structure, compact size and low cost, but a small dynamic range. The small range is caused by use of gap variation. If the sensor takes area variation type with one plate moving horizontally, it can have a large measurable range. While the area variation has relatively low sensitivity, some studies have found methods to improve the sensitivity. Even though the methods are effective, parameters of the results are limited and 2 dimensional. This study provides more practical and 3 dimensional analysis and suggests relations between parameters. Using the results, the optimized design parameters of a high dynamic range capacitive sensor can be found.

• Journal of the Korea Institute of Military Science and Technology
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• v.16 no.6
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• pp.881-888
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• 2013

A basic study was performed to develop a mini gas generator by using a commercial automotive airbag inflater. The mini gas generator can be used for industrial and military application like a seat belt pretensioner. Some parameters were experimentally investigated to reduce the size of the inflater. Basic combustion tests were performed in the closed chamber and measured the pressure and the temperature behavior according to the design parameters. From the study, essential parameters were determined to design a mini gas generator.

• Proceedings of the KIEE Conference
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• 1990.11a
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• pp.380-383
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• 1990

When the MOSPET is applied as a switching device for the resonant inverter, a damped oscillating noise is appeared at specific frequency band. This damped Oscillation is caused by the series and parallel resonance due to distributed circuit parameter of snubber and main circuit. This paper describes the frequency-impedance characteristic of the resonant inverter and optimal snubber design strategy to reduce the RF noise.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.449-451
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• 2007

We made 980 thermal conductivity measurements on igneous, metamorphic, sedimentary, and volcanic rock samples from Korea. The average thermal conductivity of igneous, metamorphic, sedimentary, and volcanic rocks are 3.41 W/m-K, 3.98 W/m-K, 4.10 W/m-K, and 3.21 W/m-K, respectively. Thermal conductivity values of a rock type generally have a wide range because thermal conductivity depends on various factors such as dominant mineral phase, micro-structure, anisotoropy and so on. Thermal properties (thermal conductivity, thermal diffusivity and specific heat) are important variables which are used to design a geothermal heat pump(GHP) system. Therefore, our thermal property data can contribute on a efficient design of a GHP system.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1530-1533
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• 2005

In this paper, we design a Linear Quadratic Gaussian controller for the active suspension. We can improve the inherent suspension problem, trade-off between the ride quality and the suspension travel by selecting appropriate weights in the LQ-objective function. Because any definite rules for selecting weights do not exist, we use an optimization-algorithm, Evolution Strategy (ES) to find the proper control gains for selected frequencies, which have major effects on the vibrations of the vehicle's state variables. The frequencies and proper control gains are used for the neural network data. During a vehicle running, the trained on-line neural network is activated and provides the proper gains for non-trained frequencies. For the full-state feedback control, Kalman filter observes the full states and Fourier transform is used to detect the frequency of the road.

• Proceedings of the KIEE Conference
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• 2004.07d
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• pp.2242-2244
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• 2004

This paper deals with the design of a reduced-order stabilizing controller for the linear system. The coupled lineal matrix inequality (LMI) problem subject to a rank condition is solved by a sequential semidefinite programming (SDP) approach. The nonconvex rank constraint is incorporated into a strictly linear penalty function, and the computation of the gradient and Hessian function for the Newton method is not required. The penalty factor and related term are updated iteratively. Therefore the overall procedure leads to a successive LMI relaxation method. Extensive numerical experiments illustrate the proposed algorithm.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.31 no.10
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• pp.868-875
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• 2007

In this paper, performance characteristics of a domestic kim-chi refrigerator are predicted by using the theoretical calculation and experimental method. The objective of this study is to find out the best design points of the refrigeration system and to calculate an adiabatic characteristic with variation to outdoor temperatures. The best design points such as refrigerant charge amount and capillary length were experimentally investigated. And the theoretical calculation is conducted as a function of calculation parameters and outdoor temperatures. According to this study results, the best design points of a refrigeration system with 2 rooms are 95 g of a refrigerant charge amount and 3500 / 3500 mm of capillary lengths and the best design points of a refrigeration system with 3 rooms are 100 g of a refrigerant charge amount and 3000/3000/6000mm of capillary lengths. And the power consumptions of both systems are 13.57 and 18.2 kWh/month. The worst part of heat loss is a front side of a domestic kim-chi refrigerator body.

• Journal of the Korean Institute of Educational Facilities
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• v.12 no.6
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• pp.26-35
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• 2005

The purpose of this study is to suggest improved Special Instruction Classrooms(SIC) in terms of architectural planning based on the analysis of design characteristics and problems. For this study, SICs in 20 elementary schools located in Daegu were selected and investigated. The results of investigation showed that: first, the vertical separation type is mostly preferred for the layout of SICs; second, the top floor is preferred for the location of SICs. We suggest that first, each SIC should be located with consideration of the characteristics of subjects(); second, the degree of adjacency-room preference for each room should be taken into consideration for the zoning of the SICs(, ); finally, a direction for improvement for suitable architectural design of each SICs should be based on the feasibility of learning space().

• Aerospace Engineering and Technology
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• v.4 no.1
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• pp.129-142
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• 2005

A semi-monocoque truncated cone structure, which is a main structure for the payload adapter of KSLV-I, was designed. Static test was performed to confirm the reliability of the cone structure under the design loads. Strains and displacements are measured during four load cases; the compressive axial, pure bending, pure shear, and combined loading conditions. The results showed that the cone structure satisfies the design requirements. An equivalent axial load was applied to the cone structure so that the global buckling of the cone structure occurred. The measured buckling load was compared with the predicted one by finite element method. The results show a good agreement.