• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.110.1-110.1
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• 2012

We studied the source regions of 12 solar energetic particle (SEP) events seen between 2010 August and 2012 January at STEREO-A, B and ACE, when the two STEREO spacecraft were separated by about $180^{\circ}$. All events were associated with strong flares (C1 - X6) and fast coronal mass ejections (CMEs) accompanied by type II radio bursts. We have determined the arrival times of the SEP events at the three spacecraft. EUV waves observed in $195{\AA}$ and $193{\AA}$ channels of STEREO and SDO/AIA are tracked across the Sun and the arrival time of the EUV wave at the photospheric source of open field lines extending to the spacecraft connection points at 2.5 Rsun estimated. We found 7 events with flux enhancements in all spacecraft and 4 in two spacecraft. Most events came from a single source. The results show that magnetic field connections between source regions and the spacecraft play an important role in abrupt flux enhancements. In the most cases, EUV waves at the Sun are associated with a wide longitudinal spread of the SEPs.

• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.303-306
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• 2000

복잡한 형상을 지닌 터빈 블래이드의 결함을 검사하기 위해 현재 $35^\circ,\; 38^\circ,\; 40^\circ$의 횡파 굴절각을 지닌 탐촉자를 사용하고 있다. 이와 같은 굴절각은 초음파 빔의 경로를 Snell의 법칙에 의해 설정하고 있다. 그러나 터빈 블래이드 검사용 초음파 탐촉자를 제작하는 과정에서 $35^\circ$의 횡파 굴절각을 갖는 경사각 탐촉자는 제작이 어려움을 알았다. 이러한 원인은 철강재료의 종파임계각이 $33.2^\circ$의 횡과굴절각에 대응되며, 종파임계각 근처에서는 전반사 현상 때문에 에너지 투과율이 매우 작아 실제 시험대상체에 입사되는 에너지가 거의 없으며 또한 횡파굴절각이 약 $37.5^\circ$ 일때에 휭파의 에너지 투과율이 최대가 되어 wedge를 $37.5^\circ$ 이하의 횡파굴절각을 갖도록 설계하더라도 측정을 하면 $37.5^\circ$ 근처의 횡파굴 절각을 갖게된다. 즉, 종파임계각 근처에서는 전반사 현상에 의해 경계면에서의 에너지 투과가 매우 작아 횡파 굴절각은 Snell의 법칙이 아닌 초음파 에너지의 투과 정도를 나타내는 echo transmittance의 크기에 의해 결정된다.

• Journal of Hydrospace Technology
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• v.2 no.2
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• pp.68-79
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• 1996

The present report describes the results of the cooperative experimental study organized by the High-Speed Marine Vehicle Committee of the Korea Towing Tank Conference. The study aims to improve model test technique and accuracy and to self-evaluate their own capabilities. The resistance tests of a 23m class planing hull were performed at the towing tanks of the Korea Research Institute of Ships and Ocean Engineering (KRISO), Hyundai Maritime Research Institute (HMRI), Seoul National University (SNU), Inha University (IU) and Pusan National University (PNU). In addition, the longitudinal wave cut was measured antral and analyzed at the KRISO. All the results of total resistance, trim and mean sinkage are presented in this report and the results show fairly good agreements comparing with the ITTC HSMV committee's report.

• Journal of Families and Better Life
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• v.29 no.6
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• pp.137-151
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• 2011

This study examines the condition of transfers between mothers and adult children, analyzing the influencing factors in such transfers. Specifically the study examines the influence of financial transfers and economic resources on financial transfers and grandchild caregiving between mothers and adult children. The sample of 3719 mothers with adult children was extracted from the first wave of the Korean Longitudinal Survey of Women and Families. The major findings are as follows. Mothers's socio-demographic characteristics are important factors in explaining financial transfers between mothers and adult children. Mothers who have jobs and spouses are more likely to provide economic resource to their adult children than those who don't have. In terms of receiving economic resources from adult children, statistically meaningful factors are mothers' age, labor market participation, marital status, household income, household asset, and children's labor market participation. Especially, labor market participation of mothers and adult children is statistically powerful factor in financial transfers and caregiving.

• Journal of Family Resource Management and Policy Review
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• v.15 no.4
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• pp.65-78
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• 2011

The purpose of this study was to examine the experience of retirement and how life satisfaction after retirement differs depending on the individual, family, and social characteristics of middle-aged and elderly Korean men and the experience of retirement. Data were drawn from the first wave of the Korean Longitudinal Study of Ageing (KLoSA). The sample consisted of 278 retired middle-aged and elderly Korean men aged between 45 and 64. The results showed that middle-aged and elderly Korean retirees' reasons for retirement differed depending on their health satisfaction. In addition, their retirement satisfaction varied according to their education, health satisfaction, economic satisfaction, and reasons for retirement. Regarding their life satisfaction, it was predicted by their age and satisfaction with health status, economic situation, marriage, and relationship with their children.

• Human Ecology Research
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• v.56 no.1
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• pp.55-69
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• 2018

This study examined how the resources from work, family and community lowered family-to-work conflict (FWC) and enhanced family-to-work facilitation (FWF) of employed women with a child younger than 18 years old in order to provide empirical support for the Korean government's effort to create a family-friendly community as a way to help employed mothers balance work and family life. Information from 608 employed mothers living in 45 different communities were extracted from the 4th-wave of the Korean Longitudinal Survey of Women and Families in 2012, while community resources indicators were selected from the 2012 database of the Korean Statistical Information Service. Findings from the HLM analysis were as follows. First, there were significant variation in FWC and FWF among employed mothers depending on the communities they resided in. Second, work satisfaction, representative of work resource, relieved FWC and enhanced FWF, but spousal support, which represents family resource, affected neither FWC nor FWF. Third, community resources, as represented by family-friendly environment and frequent volunteering by community residents, lowered FWC but failed to enhance FWF. Lastly, family-friendly community resources served to mitigate the negative relationship between work satisfaction and FWC. This study is meaningful in that it provided empirical evidence for the contribution of community resources to work-family balance of employed mothers.

• The Journal of Engineering Geology
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• v.16 no.2 s.48
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• pp.179-187
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• 2006

Two specimens of mortar containing artificial slit and Geochang granite containing the straight notch were selected to be used in this research. Source mechanism of micro-crack by radiation pattern based on dislocation the-ory was estimated by the first motion of longitudinal wave and spatial distribution between the location of transducers for monitoring acoustic emission and source coordinates determined by the application of the least square method. Result of analysis showed that the orientation of dislocation surfaces due to shear dislocation and tensile dislocation squares considerably with crack direction visually observed. The ultimate goal of this study is to provide fundamental information for source mechanism of micro-crack within materials.

• Journal of the Korean Society of Combustion
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• v.21 no.2
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• pp.29-37
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• 2016

This study described the experimental investigations of combustion instability in a model gas turbine combustor. Strong coupling between pressure oscillations and unsteady heat release excites a self-sustained acoustic wave, which results in a loud and annoyed sound, and may also lead to a structural damage to the combustion system. In this study, in order to examine the combustion instability phenomenon of a dual swirling combustor configuration, the information of heat release and pressure fluctuation period with respect to the variation in both thermal power and combustor length was collected experimentally. As a result, the fundamental acoustic frequency turned out to increase with the increasing thermal power without respect to the combustor length. The frequency response to the combustor length was found to have two distinct regimes. In a higher power regime the frequency significantly decreases with the combustor length, as it is expected from the resonance of gas column. However, in a lower power regime it is almost insensitive to the combustor length. This insensitive response might be a result of the beating phenomenon between the interacting pilot and main flames with different periods.

• Journal of Preventive Medicine and Public Health
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• v.40 no.2
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• pp.137-144
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• 2007

Objectives : According to Rowe and Kahn (1998), successful aging is the combination of a low probability of disease, high functioning, and active engagement with life. The purpose of this study was to assess the relationship between active engagement with life and functioning among the community-dwelling elderly. Methods : Data were collected from Wave 2 of the Suwon Longitudinal Aging Study (SLAS), consisting of a sample of 645 persons aged 65 and older living in the community. A social activity checklist and social support inventory were used as measures of engagement with life, along with the Physical Functioning (PF) scale as a measure of functioning. The effects of social support and social activity on physical functioning, taking into account the covariates, were analyzed by hierarchical linear regression analysis. Results : Maintenance of social activity and social support were significantly associated with higher physical function, after adjusting for sociodemographic and health-related covariates. Social support appeared to be more prominent than social activity in predicting physical functioning. Conclusions : Social support and social activity are potentially modifiable factors associated with physical function in older persons. Studies examining the role social engagement may play in preventing disability are warranted.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.11 no.6
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• pp.181-192
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• 2001

The power flow analysis (PFA) has been performed to analyze the vibration of coupled plates excited by a point force in an arbitrary direction. The point force generates the out-of-plane vibration associated wish flexural waves and the in-plane vibration associated with longitudinal and shear waves. The energy governing equation for each type of waves was introduced and solved to Predict the vibrational energy density and intensity generated by the out-of-plane and in-plane components of the point force in an arbitrary direction. The wave transmission approach was used to consider the mode conversion at the joint of the coupled plates. Numerical results for vibrational energy density and intensity on the coupled plates were presented. Comparison of the results by PFA with exact results showed that PFA can be an effective tool to predict the spatial variation of the vibrational energy and intensity on the coupled plates at high frequencies.