• 한국산학기술학회논문지
• /
• 제18권6호
• /
• pp.646-652
• /
• 2017

본 연구는 한국 아동 청소년 패널조사를 활용하여 청소년의 우울과 신체화 증상에 대한 종단적 상호 인과관계를 자기회귀교차지연 모형을 통해서 확인하기 위해 실시하였다. 본 연구의 대상자들은 한국청소년정책연구원에서 실시하는 한국 아동 청소년 패널조사 2011년 2차, 2013년 4차, 2015년 6차에 모두 참여한 1968명의 청소년들을 대상자로 선정하였고, SPSS 18.0 프로그램과 AMOS 18.0 프로그램을 이용하여 자료를 분석하였다. 연구결과, 이전 시점의 우울과 신체화 증상은 모두 다음 시점의 우울과 신체화 증상에 영향을 미치는 것으로 나타났으며, 이전 시점의 우울은 다음 시점의 신체화 증상의 교차지연효과에도 영향을 미치는 것으로 나타나 이전 시점의 우울의 정도가 높을수록 다음 시점의 신체화 증상의 정도가 높아지는 것으로 나타났다. 또한 이전 시점의 신체화 증상은 다음 시점의 우울의 교차지연효과에도 영향을 미치는 것으로 나타나 이전 시점의 신체화 증상의의 정도가 높을수록 다음 시점의 우울의 정도가 높아지는 것으로 나타났다. 본 연구는 청소년의 정신건강 간호중재를 위한 기초자료를 마련했다는데 의의가 있으나, 인지적이고 심리적인 요인들은 다양한 요인들에 의해 변화하기 때문에 이와 관련된 종단적 연구들도 필요하다고 생각한다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1995년도 하계학술대회 논문집 C
• /
• pp.1350-1352
• /
• 1995

This paper discribed the characteristic of I-t cross-over-point between current limited-fuse and explusion fuse(Bay-O-Net Fuse) and fuse protection in pad-mounted transformer that was generated internal faults and the short circuit of secondary side(load side). In the I-t cross-over-point, current limited fuse was melted when transient recovery voltage was raised rapidly.

• 대한화장품학회지
• /
• 제10권1호
• /
• pp.8-12
• /
• 1984

Increasing the oil volume in the oil : water mixtures using isopropyl myristate, oleic acid as oils, the solubilities of methyl, propyl and butyl parabens and the MICs (minimum hibitory concentrations) to E. coli were increased. But in liquid paraffin, the solubility was reversed. The relation between MIC and solubility of parabens had constant factor of 0.7 as saturation fraction percent. The solubility of methyl paraben was crossed over in those of propyl and butyl parabens, when the oil volume was increased. When the oil was used over the cross-over point, methyl paraven was useful to preserve the systems, and below the cross-over point the more lipophilic propyl and/or butyl parabens were effective.

• Fibers and Polymers
• /
• 제7권4호
• /
• pp.328-332
• /
• 2006

Poly(ethylene terephthalate) (PET) and poly(ethylene glycol) (PEG) copolymers cross-linked with pentaerythritol, a four-way cross-linker, are prepared to compare their mechanical and shape memory properties with the one cross-linked by glycerol. Composition of PEG and pentaerythritol is varied to search for the one with the best mechanical and shape memory properties. The highest shape recovery rate is observed for the copolymer composed of 30 mol% PEG-200 and 2.5 mol% pentaerythritol. Four-way cross-linking by pentaerythritol significantly improves shape recovery rate and retention of high shape recovery rate after repeated use compared to the one cross-linked by glycerol, a three-way cross-linker, and difference and advantage of additional cross-linking point are discussed.

• 한국자동차공학회논문집
• /
• 제16권2호
• /
• pp.87-92
• /
• 2008

The breakup processes and spray plume characteristics of liquid jets injected in subsonic air cross-flows were experimentally studied. The behaviors of column, penetration, breakup of plain liquid jet and droplet sizes, velocities have been studied in non-swirling cross-flow of air. Nozzle has a 1.0 mm diameter and Lid ratio=5. Experimental results indicate that the breakup point is delayed by increasing air momentum, the penetration decreases by increasing Weber number and the split angle is increased by increasing air velocity or decreasing injection velocity. SMD increases according as increasing height or decreases in accordance with increasing air velocity. This phenomenon is related to the momentum exchange between column waves and cross-flow stream. Droplet vector velocities were varied from 11.5 to 33 m/s. A higher-velocity region can be identified in down edge region at Z/d=40, 70 and 100. Lower-velocity region were observed on bottom position of the spray plume.

• 한국컴퓨터정보학회논문지
• /
• 제24권7호
• /
• pp.153-160
• /
• 2019

This study aims to analyze the mutual influences between adolescents' multicultural acceptability and school adjustment. Research problems for research are as follows. First, is multicultural acceptability and school adjustment stable over time? Second, what is the longitudinal impact of school adjustment on multicultural acceptability over time? Third, what is the longitudinal impact of multicultural acceptability on school adjustment over time? The results of analyzing the research problems by applying the autoregressive cross-lagged model are as follows. First, the autoregressive model of school adjustment has a significant effect on the future time point and is stable over time. Second, the autoregressive model of multicultural acceptability have a significant effect on the future time point and is stable over time. Third, cross-lagged effect from school adjustment to multicultural acceptability has a statistically significant effect on the multicultural acceptability at a later time, and is stable over time. Fourth, cross-lagged effect from multicultural acceptability to school adjustment was not statistically significant at the time of multicultural acceptability, and there was no change with time. This study is meaningful to provide the theoretical and practical implications by verifying the influence of the three - year term data over time.

• 대한간호학회지
• /
• 제49권1호
• /
• pp.69-79
• /
• 2019

Purpose: This study aimed to identify the directionality of the causal relationship and interaction between depression and amount of smoking over time in hardcore smokers using longitudinal descriptive analysis. Methods: Secondary data from the Korean Welfare Panel Study were analyzed using autoregressive cross-lagged modeling. Participants included 342 hardcore smokers who participated in the 8th to 11th waves of the panel study. Results: Analyses revealed that change(s) in depression levels according to time had a significant positive relationship with the total amount of smoking per day (${\beta}=.29$, ${\beta}=.19$, ${\beta}=.17$, p<.001), while change(s) in total amount of smoking per day according to time had a significant positive relationship with depression (${\beta}=.43$, ${\beta}=.50$, ${\beta}=.38$, p<.001). Analysis of the cross-lagged effect between depression and total amount of smoking per day showed that depression at one time point had a significantly positive relationship with the total amount of smoking per day at the next time point (${\beta}=.14$, ${\beta}=.13$, ${\beta}=.13$, p=.021), and that the total amount of smoking per day at one time point had a significant positive relationship with depression at the next time point (${\beta}=.04$, ${\beta}=.04$, ${\beta}=.03$, p=.044). Conclusion: The findings in the present study confirmed a cross-interaction between depression and total amount of smoking per day in hardcore smokers. The present findings could be used to develop appropriate smoking-related interventions.

• 소음진동
• /
• 제7권1호
• /
• pp.43-53
• /
• 1997

This paper investigated the practical use for measuring the structural intensity (power flow per width of cross section) in a uniform semi-infinite beam in flexural vibration. The structural intensity is obtained as a vector at a measurement point, One-dimensional structural intensity can be obtained from 4-point cross spectral measurement, or 2-point measurement on the assumption of far field. The measurement errors due to finite difference approximation and phase mismatch of accelerometers are examined. For precise measurements, it would be better to make the value of k$\delta$(wave number x space between accelerometers) between 0.5 and 1.0. Formulation of the relation between bending waves in structures and structural intensity makes it possible to separate the wave components by which one can get a state of the vibration field. Experimental results are obtained from 2- and 4-point measurement performed at 200mm (near field) and 400mm (far field) apart from excitation point in random excitation. the results are compared with the theoretical values and measured values of input power spectrum in order to verify the accuracy of structural intensity method, 2-point method is suggested as the practical structural intensity method.

• 자원환경지질
• /
• 제41권2호
• /
• pp.219-223
• /
• 2008

해양에서 관측되는 해양지구물리 탐사자료에는 위치오차, 기기오차, 관측오차, 해상 상태 등 다양한 원인에 기인하는 오차가 포함되어 있다. 이에 의해 한 기관에서 해양지구물리 탐사 자료를 취득할 때나 여러 기관에서 취득된 해양지구물리 탐사자료를 취합할 때 많은 교차점오차가 발생하고, 이러한 교차점오차는 부적절한 해석을 야기하는 인위적인 이 상대를 만든다. 교차점오차를 줄이기 위한 다양한 방법들이 제시되었지만, 이들 대부분의 방법들은 교차점을 찾기 위해 각각의 점자료(point data) 혹은 선분자료(segment data)를 모두 비교함으로써, 불필요하게 많은 계산시간을 요구하게 된다. 따라서 본 연구에서는 중복구역나눔 방법을 도입하여 빠르게 교차점을 찾고, 가중치선형내삽 방법을 이용하여 교차점오차를 보정하는 포트란(FORTRAN) 프로그램 (FastXcorr)을 개발하였다.

• Journal of the Korean Society for Industrial and Applied Mathematics
• /
• 제9권2호
• /
• pp.29-43
• /
• 2005

We consider a surface reconstruction problem from geometrical points (i.e., points given without any order) distributed on a series of smooth parallel cross sections in ${\mathbb{R}}^3$. To solve the problem, we utilize the natural points ordering method in ${\mathbb{R}}^2$, described in [18], which is a method of reconstructing a curve from a set of sample points and is based on the concept of diffusion motions of a small object from one point to the other point. With only the information of the positions of these geometrical points, we construct an acceptable surface consisting of triangular facets using a heuristic algorithm to link a pair of parallel cross-sections constructed via the natural points ordering method. We show numerical simulations for the proposed algorithm with some sets of sample points.