• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.491-492
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• 2008

This paper describes the series-gap characteristics of transmission line arrester with switching and lightning impulse flashover test. The transmission line arrester exhibited external gap because it is must not flashover with switching impulse on the other hand it is must flashover with lightning impulse. In accordance, minimum and maximum length of series-gap was determinated with these tests. As gap length is increased flashover voltage was increased in the range of 315.4 kV~496.3 kV and negative polarity exhibited a high voltage. As a result, It was thought tat the series-gap length of transmission line arrester exhibited in the range of 580 mm~1100 mm.

• 한국전기전자재료학회논문지
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• 제33권1호
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• pp.56-59
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• 2020

Porcelain insulators are typically exposed to surface discharge and lightning impulse in service. This study investigates the insulation characteristics of the external and internal discharges of a porcelain insulator with respect to its flashover for a 154 kV transmission line. The experiments are also conducted using a wet flashover test and an impulse test based on the external discharge and the internal penetration, to classify the flashover voltage-time curve of the porcelain insulator. When an impulse with a strength of 2,500 kV/㎲ was applied three times to 6.5 mm ceramic samples, electrical penetration of approximately 70% occurred. The impulse experiment confirmed that the electrical penetration inside the porcelain insulator coincided with the area where the electric field was concentrated. The wet flashover voltage test revealed that the flashover threshold voltage increases by approximately 7% after cleaning of the surface.

• 복식문화연구
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• 제16권1호
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• pp.166-180
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• 2008

These days, sexual harassment in the workplace or at school is being socially visualized. In this study, the desirable direction for clothing behavior is suggested by discussing the relationship between sexual desire and clothing. The relationship between sexual impulse and clothing is provided by studying college student's general opinion about sexual desire, also different ideas from females and males about the clothes that cause sexual impulses were studied, moreover, the desirable direction for clothing behavior is suggested by comparing the perceptions of college students about overly revealing clothing. This study performed the self description method and in-depth interview method on male and female college students at 3 University for 3 weeks from May, 28, 2007 to June, 23, 2007. After which 564 survey papers were distributed. The program SPSS WIN 12.0 was used to statistically analyze the data Frequency analysis, cross analysis, T-test, and a reliability test were performed on the study subject. According to the study results, sexual impulses are affected not only by internal factors but also external factors such as clothing and it is an important point. Women should not only pursue an attractive external appearance but also consider how other people think and respond to the message, and they should protect themselves from sexual harassment, or sexual violence, which are anti-social behaviors, by wearing clothes that are less stimulating.

• 제어로봇시스템학회논문지
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• 제11권6호
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• pp.543-549
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• 2005

This paper deals with modeling and analysis fer the landing motion of a human-body model. First, the dynamic model of a floating human body is derived. The external impulse exerted on the ground as well as the internal impulse experienced at the joints of the human body model is analyzed. Second, a motion planning algorithm exploiting the kinematic redundancy is suggested to ensure stability in terms of ZMP stability condition during a series of landing phases. Four phases of landing motion are investigated. In simulation, the external and internal impulses experienced at the human joints and the ZMP history resulting from the motion planning are analyzed for two different configurations. h desired landing posture is suggested by comparison of the simulation results.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.84.2-84
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• 2002

$\textbullet$ The dynamic model of a floating human body is derived $\textbullet$ Introduction to impact model for human body $\textbullet$ Analysis of external impulse on the sole $\textbullet$ Analysis of internal impulse at the joints $\textbullet$ It is shown through simulation that the internal impulses for two different configurations

• Structural Engineering and Mechanics
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• 제13권3호
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• pp.329-343
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• 2002

In this research, the dynamic stability of an orthotropic elastic conical shell, with elasticity moduli and density varying in the thickness direction, subject to a uniform external pressure which is a power function of time, has been studied. After giving the fundamental relations, the dynamic stability and compatibility equations of a nonhomogeneous elastic orthotropic conical shell, subject to a uniform external pressure, have been derived. Applying Galerkin's method, these equations have been transformed to a pair of time dependent differential equations with variable coefficients. These differential equations are solved using the method given by Sachenkov and Baktieva (1978). Thus, general formulas have been obtained for the dynamic and static critical external pressures and the pertinent wave numbers, critical time, critical pressure impulse and dynamic factor. Finally, carrying out some computations, the effects of the nonhomogeneity, the loading speed, the variation of the semi-vertex angle and the power of time in the external pressure expression on the critical parameters have been studied.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2009년도 추계학술대회 논문집
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• pp.331-334
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• 2009

This paper presents the characteristics of external inductor for impulse current waveform with 10/350 ${\mu}s$ time parameters. Impulse generator was composed with capacitor having large capacitance and low working voltage for the safe of operator and small discharging sound. Parallel R-L-C circuits with crow-bar gaps and superposition method were proposed to make a high current lightning impulse according to IEC 62305-1. The high energy inductor with several taps for fitting half decay time T2 within the tolerance range and experimental data of inductance according to charging voltages were suggested.

• 한국소음진동공학회논문집
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• 제14권5호
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• pp.377-384
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• 2004

An Amplitude Proportional Friction Damper (APFD), in which the friction force is proportional to the system displacement, has been introduced and mathematically modeled. To understand the damping characteristics of APFD, analytical solutions for the impulse response has been derivedand compared to the viscous damper. It is found that APFD system has very similar damping characteristics to viscous damper even though it is a friction damper. APFD may be used as a cost-effective substitution for the viscous damper and could also be used to improve the simple friction or Coulomb dampersince APFD works with no stick-slip and always returns to original position when external disturbance is disappeared.

• Journal of Electrical Engineering and Technology
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• 제13권3호
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• pp.1346-1354
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• 2018

Quality of the power system depends upon the reliability of its components such as transformer, transmission lines, insulators, circuit breakers and isolators. The transient voltage due to internal or external reasons may affect the insulation level of the components. The insulation level of these components must be tested against these conditions. Different studies, testing of different electrical components against high voltage impulses and different industrial applications rely on the international manufactures for pulsed power generation and testing, that is quite expensive and large in size. In this paper a model of impulse voltage generator with capacitive load of pin type insulator is studied by simulation method and by an experimental setup. A ten stage high voltage impulse generator (HVIG) is designed and implemented for different applications. In this proposed model, the cost has been reduced by using small and cheap capacitors as an alternative for large and expensive ones while achieving the same effectiveness. Effect of the distributed capacitance in each stage is analyzed to prove the effectiveness of the model. Different values of front and tail resistances have been used to get IEC standard waveforms. Results reveal the effectiveness at reduced cost of the proposed model.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 추계학술대회 논문집 전력기술부문
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• pp.454-456
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• 2003

This paper describes a type test results of 154 kV transmission line arrester with external gap. The test was carried on surge arrester unit and line arrester with external gap, respectively. Withstand voltage test demonstrate the voltage withstand capability of the line arrester with external series gap under the dry and wet conditions. In insulation coordination test external series gap shall be discharged every time when lightning impulse voltage with the steepness of more than 1500 $kV/{\mu}s$ are applied under the wet condition.