• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.24 no.6
• /
• pp.653-659
• /
• 2015

The aim of this study is to develop a technique for the accelerated life test of the capacitor in a propulsion control device of a traction inverter used for a high-speed train. Using this technique, the accelerated life test can possibly estimate the life cycle of a capacitor under various temperature conditions and irregularly applied voltage. The accelerated life test is conducted for the capacitor of the traction inverter. The common proceedings of this test are selection of failure mechanism, determination of accelerated stress, range determination of the accelerated stress, determination of the test condition, and distribution and determination of the sample. From this result, the continuous applied voltage was not considered for the acceleration factors anymore. Therefore, the final result having an acceleration factor of 9.4 (= 13,626/1,445) was observed. Furthermore, the life-shortening acceleration effect for the irregular applied voltage condition can be applied to various situations.

• Journal of Industrial and Engineering Chemistry
• /
• v.67
• /
• pp.461-468
• /
• 2018

A highly sensitive, selective and rapid method for the determination of lead based on the reaction of lead (II) with 5-(4'-chlorophenylazo)-6-hydroxypyrimidine-2,4-dione (CPAHPD) and the solid phase extraction of the Pb(II)-CPAHPD complex with Amberlite XAD-2000 was developed, in the presence of pH 5.6 buffer solution and Triton X-114 medium. CPAHPD reacts with lead to form a violet complex with a molar ratio of 2:1 (CPAHPD to lead). This complex was enriched by the solid phase extraction with Amberlite XAD-2000. An enrichment factor of 500 was obtained by elution of the complex from the resin with a minimal amount of isopentyl alcohol(0.2 mL). In isopentyl alcohol medium,the molar absorptivity of the complex is $1.13{\times}10^6L\;mol^{-1}cm^{-1}$ at 647 nm. Beer's law is obeyed in the range of $5.0-160ng\;mL^{-1}$ in the measured solution. The relative standard deviation for 10 replicate samples of $50ng\;mL^{-1}$ level is 1.26%. The detection and quantification limits reaches 1.5 and $4.7ng\;mL^{-1}$ in the original samples. The presented procedure was successfully applied for determination of lead content in real samples such as vegetables, waters, biological and soil samples with satisfactory results.

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2000.11a
• /
• pp.136-138
• /
• 2000

The vehicle emissions of primary air pollutants are described by the emission factor (EF), defined as the emitted mass (g) of a compound per distance (km) and vehicle. The EF can be determined by exhaust measurements from single vehicles in dynamometric tests. However, the EF of a large number of vehicles has to be measured to obtain the representative results for actual road traffic emissions. Road traffic emissions can also be determined by exhaust measurements of driving vehicles or in tunnel measurements. (omitted)

• Proceedings of the Korea Information Processing Society Conference
• /
• 2023.11a
• /
• pp.371-373
• /
• 2023

factor 들이 많은 데이터의 군집화는 어려움을 요한다. K-means 클러스터링을 사용하여 군집화를 할 때, 각 데이터들이 가진 factor 의 개수가 상이한 경우 비슷한 성향을 가진 데이터임에도 불구하고 클러스터링이 적합하게 되지 않는 현상이 발생한다. 이러한 문제점을 해결하기 위해 최적의 군집화 개수를 결정하는 실루엣 기반 방법을 제안하고 제안기법의 성능을 평가한다.

• Journal of Environmental Impact Assessment
• /
• v.7 no.2
• /
• pp.113-125
• /
• 1998

The amount of mercury emitted from an incinerator depends on the properties of waste, combustion condition, and control devices. Mercury concentration in air proportionates to the increase of incinerator installation. The purpose of this study is to provide a method for determination of mercury emission factor which can predict the amount of mercury emitted from each incinerator specifically. Case study was performed for N municipal waste incinerator. Based on the method presented in this paper, we obtained mercury emission factor as 1.85~1.95 g Hg/t at N Municipal Waste Incinerator and this result was regarded as reasonable when compared with existing mercury emission factor in reference cases. Fluorescent lamps turned out to be the most important source(44.4%) of mercury in municipal waste and its amount will tend to increase, while batteries become less significant. In addition, medical waste is one of the major source of mercury.

• Transactions of Materials Processing
• /
• v.1 no.1
• /
• pp.42-51
• /
• 1992

The ring compression test has been widely employed as an experimental means to determine the friction factor. The calibration curves are obtained by the rigid-plastic finite element analysis for various work-hardening exponent and strain-rate hardening exponent. The effects of work-hardening exponent and strain-rate hardening exponent are thoroughly studied and discussed from the finite element computation. The change of friction factor during height reduction in ring compression is also discussed. Then, the method to estimate the change of friction factor during ring compression is proposed.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.27 no.6
• /
• pp.550-555
• /
• 2007

Stress intensity factor is one of the most important parameters in fracture mechanics. Both the stress field distribution and the crack propagation are closely related to these parameters. Due to the complexity of actual engineering problems, it is difficult to calculate the stress intensity factor by theoretical formulation, so photoelasticity method is a good choice. In this paper, modified two parameter method is employed to calculate stress intensity factor for opening mode by using data from more than one photoelastic fringe loop. For getting accurate experiment results, the initial fringes are doubled and sharpened by digital image programs from the fringe patterns obtained by a CCD camera. Photoelastic results are compared with those obtained by the use of empirical equation and FEM. Good agreement shows that the methods utilized in experiments are considerably reliable. The photoelastic experiment can be used for bench mark in theoretical study and other experiments.

• The Journal of the Acoustical Society of Korea
• /
• v.14 no.5
• /
• pp.29-35
• /
• 1995

Nonlinear distortion arising from the nonlinear movement of the loudspeaker diaphragm degradates the tone quality. The distortion is, in low frequency range, mainly caused by nonlinear characteristics of the suspension stiffness and the force factor. In this paper, the nonlinear suspension stiffness and the nonlinear force factor are modeled to the quadratic functions and a method is proposed to determine their coefficients. An additional mass to the diaphragm moved the quiescent point of the diaphragm and uncoupled the stiffness and the force factor. This made it possible to deter mine the coefficients of the nonlinear suspension stiffness by measuring the resonance frequencies at several quiescent points. The coefficients of the nonlinear force factor are then determined by fitting the curve which is calculated from the waveforms of input voltage and input current, and the displacement of the diaphragm at resonance frequency.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.20 no.9
• /
• pp.2792-2799
• /
• 1996

It was shown in the previous study that the numerically derived elastic work factor for CLS specimen was independent of fiber direction for a unidirectional case. Also, it was proposed the elastic work factor could be used to determine energy release rate from a single test record. In the present study, elastic work factor was derived from a simple beam theory to investigate its dependence on material property and geometric condition. Also, the elastic work factor of CLS specimen was applied experimentally to determine critical energy release rate in order to prove its validity determining critical energy release rate from a single specimen. For this purpose, critical energy release rate determined using the elastic work factor was compared with that determined by the compliance method. The results showed that while elastic work factor is affected by $t_2/t_1$ and $L_2/L_1$ it is independent of fiber angle for a unidirectional case. It was also found that critical energy release rates determined by both methods are comparable each other, thus elastic work factor approach can be used to determine energy release rate from a single test specimen.

• Journal of the Korea Society of Computer and Information
• /
• v.25 no.5
• /
• pp.199-208
• /
• 2020

The purpose of this study is to analyze the influence of career support and teacher relations of parents in order to determine the career determination of multicultural youths, and to confirm the influence of career preparation between parental career and care support and teacher relations. To this end, data from 2017 (the 7th year) was used among the data from the Multicultural Youth Panel Survey (MAPS). According to the analysis results, first, career support, teacher relations, and career preparation of multicultural youth parents have a positive impact on career determination. Second, the importance of the relative influence of career preparation, which is an internal context factor, was also confirmed in the process of determining the career path of multicultural youths. Third, it was analyzed that the higher the career and childcare support of multicultural youth parents, the more positive the teacher relationship, the higher the career determination. Career preparation was confirmed to play a role in mediating career support and teacher relations among multicultural youth parents in determining career paths. Based on the results of this analysis, practical alternatives were proposed to enhance the career determination of multicultural youths.