• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.1044-1048
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• 2001

This paper proposes a nonlinear impedance circuit composed by diodes and inductors or capacitors. This circuit needs no control circuits and switches, and the impedance value is changed by the polarity of current or voltage. This paper presents one of these applications to improve the input current of capacitor input diode rectifiers. The rectifier using the nonlinear impedance circuit id constructed with four diodes and four capacitors in addition to the conventional rectifiers, that is, it has eight diodes and five capacitors, including a DC link capacitor. It makes harmonic components of the input current reduce and the power factor improve. A circuit design method is shown by experimentation and confirmed simulation. It explained that compared conventional pulse-width modulated (PWM)inverter with half pulse-width modulated (HPWM) inverter proposed HPWM inverter eliminated dead-time by lowering switching loss and holding over-shooting.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.05b
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• pp.967-970
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• 2003

본 논문에서는 멀티미디어 게임 흡인요소를 매개로 유식학 수행단계와 행동수정방법간의 연관성을 밝혔다. 수행단계와 흡인요소간의 연관성 파악을 위하여 11가지 선심소를 기저범주로 놓고 Roget 시소러스를 이용하여 참조정보를 탐색한 곁과 선심소의 상세범주를 얻었다. 이것과 함께 게임 흡인요소 분류를 Roget 시소러스에서 같은 방법으로 탐색하여 수행단계와 게임 흡인요소의 대응관계를 확인하였다. 한편, 게임 흡인요소에 대응하는 행동수정방법은 문헌연구를 통하여 확인하였다. 이로써 게임 흡인요소 악영향 순화방안을 서구의 심리학이론인 행동수정방법과 함께 불친 심리학인 유식학 이론의 수행방법을 적용하여 상호보완적으로 생각할 수 있었다.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.11c
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• pp.2451-2454
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• 2002

본 논문에서는 유식학의 선심소와 멀티미디어 게임 흡인요소간의 연관성을 밝혔다. 11가지 선심소를 기저범주로 놓고 Roget 시소러스를 이용하여 참조정보를 탐색한 결과 선심소의 상세범주를 얻었다. 이것을 게임의 흡인요소 분류표와 대조를 통하여 선심소와 게임 흡인요소의 대응관계를 확인하였다. 이로써 게임의 흡인요소를 유식학 이론의 입장에서 파악할 수 있는 토대를 마련하여, 유식학의 수행법으로 게임이 가지는 부정적 흡인요소의 영향을 완화시킬 수 있는 방법을 강구할 수 있었다.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.05a
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• pp.74-75
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• 2014

In remodeling business or construction of both new strucures and existing structures, Case that pile foundation was set is often. Micro pile, holding compressive force and tensile force by spherical friction, is supported by skin friction rather than end bearing capacity. but, This is weak in tension. Active area of micro pile's skin friction is narrow and micro pile don't do unification behavior hence. So bearing capacity was not fully mobilized in existing researching. In this study, in order to compensate for this method, micro pile to install Resisting Fixture is proposed.

• Korean Chemical Engineering Research
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• v.52 no.3
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• pp.289-293
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• 2014

In making emulsion type pressure sensitive adhesive (PSA), environmentally friendly Tween series nonionic surfactants were used to find out the possibility of substituting the traditional nonyl-phenyl nonionic surfactant (NP-40) by comparing their adhesive properties. Results exhibited that the PSA used Tween series nonionic surfactants showed much better adhesive properties in peel strength and holding power than that used NP-40.

• Proceedings of the KIEE Conference
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• 1999.07f
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• pp.2662-2664
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• 1999

To improve the current waveform of diode rectifiers, we propose a new operating principle for the voltage diode rectifiers. In the conventional voltage rectifier circuit, relatively large capacitors are used to boost the output voltage, while the proposed circuit uses smaller ones and a small reactor not to boost the output voltage but improve the input current waveform. A circuit design method is shown and confirmed simulation. It explained that compared conventional SPWM inverter with HPWM(Half Pulse-width modulated)Inverter. Proposed HPWM inverter eliminated dead-time by lowering switching loss and holding over-shooting. Output voltage and current of this paper were applied for real air-conditioner.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1992.10a
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• pp.101-105
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• 1992

Machined graphite/epoxy composite surfaces were studied by using SEM(Scanning Electron Microscopy). surface profilometry and its analysis to determine suitable surface describing parameters for machined unidirectional and laminate composite surface. The surface roughness and profile are found to be highly dependent on the fiber layup direction and the measurement direction. Machined unidirectional and 0.deg. 45 .deg. 90 .deg. plies in laminate composite surface profiles are found to be Gaussian in the direction of machining. Since there exist bare fibers without matrix smearing in 0 .deg. ply, higher surface roughness values were found in this orientation. It was possible to machine 90 .deg. and -45 .deg. plies due to the adjacent plies, which were holding those plies. It was found that the microgeometrical variations in terms of roughness parameters Ra without Dy (maximum Damage Depth) region and Dy are better descriptors of the machined laminate composite surface than commonly used roughness parameters Ra and Ra. The characteristics of surface profiles in laminate composite are well represented in CHD (Cumulative Height Distribution) plot and PPD (Percentage Probability Density) plot. Also, the power spectral density function is shown to be capable of identifying the wavelength distribution of the machining damage.

• Design & Manufacturing
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• v.14 no.1
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• pp.30-35
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• 2020

Plastic pulleys used for the purpose of power transmission have to very high roundness characteristics. The roundness of plastic pulleys is influenced by many factors. In this study, the effect of molding conditions on the roundness of pulleys was analyzed using a numerical analysis program. To improve the roundness, molding conditions that minimize the amount of deformation of the pulley were studied through an experimental design method. Among the experimental design methods, the Taguchi method was used, and the main molding conditions affecting the deformation of the pulley were the resin temperature and the holding pressure. It was found that the amount of deformation is reduced by about 2.86% when molding with the optimum molding conditions compared to when the optimum molding conditions are not applied.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1309-1313
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• 2008

This paper suggests an example of modification of the durability test specifications of electronic control unit for an automotive system in phase of design validation. The basic concept to redefine the specifications of durability test is based on the Arrhenius relationship for accelerated temperature test and the modified Coffin-Manson model for temperature cycle test. The ambient temperature of the powered-event durability test is increased to reduce the required test time of the current specification. Furthermore, the holding time between the events to cool down the temperature of the components is shortened and the resultant temperature rise affects the durability of the components. Thus, the acceleration factor due to the increased temperature range of temperature cycle is also estimated by the modified Coffin-Manson model.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.11 no.1
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• pp.33-38
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• 2015

The effects of post weld heat treatment(PWHT) on the mechanical properties of 2.25Cr-1Mo steels were investigated. As the PWHT temperature or holding time increased, the strength of low alloy steels progressively decreased due to softening process. After the conventional PWHT, the strength was larger than the minimum value of materials specification. The Charpy impact energy was hardly affected by the conventional PWHT. The trend of mechanical properties was analyzed in terms of tempering parameter. Most materials replaced from a power plant met the requirements of materials specification except for one heat. Same heat of materials with low impact energy were attributed to the voids formed during casting process.