• 한국철도학회:학술대회논문집
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• 한국철도학회 2002년도 추계학술대회 논문집(II)
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• pp.826-833
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• 2002

In recent years, due to the continuous concentration of population and sharp increment of commuters around Seoul metropolitan area, traffic jam has become one of severe problems along with housing in this area. In oder to solve the problem like the one mentioned above, several countries such as Japan, France and so on gradually operate double deck trains as efficient, reliable and comfortable mass transportation systems. However, the double deck train has weak points such as big cross sectional area and high mass center that cause unsafe vehicle running performances and interface problems between the vehicles and infrastructures. Therefore, prior to operate double deck trains on the existing lines, careful investigations should be performed. For these reasons, we have investigated foreign double deck trains and studied the technologies for a double deck train as an alternative way to carry heavy transportation efficiently and comfortably.

• Communications for Statistical Applications and Methods
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• 제22권3호
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• pp.305-312
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• 2015

We extend a generalized partially linear single-index model and newly define a generalized partially double-index model (GPDIM). The philosophy of sufficient dimension reduction is adopted in GPDIM to estimate unknown coefficient vectors in the model. Subsequently, various combinations of popular sufficient dimension reduction methods are constructed with the best combination among many candidates determined through a bootstrapping procedure that measures distances between subspaces. Distinguishing values are newly defined to match the estimates to the corresponding population coefficient vectors. One of the strengths of the proposed model is that it can investigate the appropriateness of GPDIM over a single-index model. Various numerical studies confirm the proposed approach, and real data application are presented for illustration purposes.

• 응용통계연구
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• 제8권1호
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• pp.27-38
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• 1995

본 논문에서는 사회적으로나 개인적으로 매우 민감한 조사에서 모집단이 양적속성을 갖는 여러 개의 층으로 구성되어 있을 때, 층의 크기를 모르는 경우 층화표본을 위하여 이중추출법을 이용하는 층화이중추출법에 의한 양적속성의 무관질문모형을 제안하였다. 그리고, 층화이중추출에 있어서 각 층의 표본배분에 관해 비례배분, 최적배분으로 나누어 각 층의 크기를 알고 있는 경우에 층화추출법에 의한 양적속성의 무관 질문모형과 그 효율성을 비교하였다.

• 천문학회보
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• 제44권1호
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• pp.47.4-47.4
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• 2019

Recent observations on the double red clumps in the bulge validate the close connection in stellar populations between Galactic globular clusters (GCs) and the Milky Way (MW) bulge. Intriguingly, diverse phenomena observed in early-type galaxies (ETGs) and their GC systems are also indicating the similarities with Galactic GCs with multiple populations. Here, we present the population synthesis for the Galactic bulge and ETGs using stellar populations observed in the Galactic GCs with multiple populations. Our new models well explain observations of both the MW bulge and ETGs. Also, the inclusion of GC-originated population to the population synthesis model shows substantial impacts on the age-dating of stellar populations. The implication of this result for the interpretation of the formation history and the age-dating of ETGs will be discussed in detail.

• 한국인구학
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• 제29권1호
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• pp.71-95
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• 2006

이 연구에서는 결혼 만족과 결혼 안정에 영향을 미치는 관련 변인들을 실증 분석하였으며, 특히 성에 대한 이중 기준이 결혼 만족과 결혼 안정의 관계에 어떤 영향을 미치는지에 분석의 초점을 두었다. 이 단계 군집표집에 의해 선정된 370명의 기혼 여성으로부터 수집된 자료를 다단계 다중회귀분석을 통해 분석하였다. 결혼 만족에 영향을 미치는 요인으로는 부부간의 상호소통, 친밀성, 성적 만족을 분석에 포함시켰으며, 결혼 안정에 영향을 미치는 요인으로는 조사 대상자의 경제활동 여부, 가구 소득 수준 결혼 만족을 분석에 포함시켰다. 그리고 성에 대한 일반적 태도를 바탕으로 조사 대상자를 성에 대한 단일 기준 집단과 이중 기준 집단으로 나누었다. 분석의 결과는 부부간의 상호 소통과 친밀성은 결혼 만족에 영향을 미치나, 성적 만족은 결혼 만족과 관계가 없음을 보여 주고 있다. 그리고 결혼 만족과 결혼 안정은 매우 높은 관계를 보이고 있는데, 성에 대한 이중 기준이 결혼 만족과 결혼 안정의 관계 수준을 약화시키는 것으로 나타났다.

• 대한기계학회논문집B
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• 제31권7호
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• pp.620-627
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• 2007

In this paper, we adapt a modified internal energy non-equilibrium first-order extrapolation thermal boundary condition to the thermal lattice Boltzmann model (TLBM). This model is the double populations approach to simulate hydrodynamic and thermal fields. The bounce-back boundary condition which is a traditional boundary condition of lattice Boltzmann method has only a first order in numerical accuracy at the boundary and numerical instability. A non-equilibrium first-order extrapolation boundary condition has been verified to be of better numerical stability than the bounce-back boundary condition and this boundary condition is proved to be of second-order accuracy for the flat boundaries. The two-dimensional natural convection flow in a square cavity with Pr=0.71 and various Rayleigh numbers are simulated. The results are found to be in good agreement with those of previous studies.

• 천문학회보
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• 제42권2호
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• pp.77.4-78
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• 2017

The presence of double red clump (RC; metal-rich counterpart of horizontal-branch) in high latitude field of the Milky Way (MW) bulge is widely interpreted as evidence for an X-shaped structure originated from the bar instability. However, Lee et al. (2015) recently suggested an alternative model, according to which the double RC is metal-rich manifestation of multiple stellar population phenomenon observed in globular clusters (GCs). Here we show that stars in bright RC are enhanced in CN compared to those in faint RC from our low-resolution spectroscopy. CN traces N, and N-rich stars are also enhanced in Na and He in GCs. Since GCs are the only environment that produce second generation stars with enhanced N, Na, & He, this is a direct evidence that stars in the classical bulge component of the MW were mostly provided by proto-GCs.

• 한국시스템다이내믹스연구
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• 제7권1호
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• pp.67-90
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• 2006

A series of system dynamics model was developed for forecasting demand and supply of human resource in the electricity industry. To forecast demand of human resource in the electric power industry, BLS (Bureau of Labor Statistics) methodology was used. To forecast supply of human resource in the electric power industry, forecasting on the population of our country and the number of students in the department of electrical engineering were performed. After performing computer simulation with developed system dynamics model, it is discovered that the shortage of human resource in the electric power industry will be 3,000 persons per year from 2006 to 2015, and more than a double of current budget is required to overcome this shortage of human resource.

• 지역사회간호학회지
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• 제31권3호
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• pp.269-278
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• 2020

Purpose: The study was conducted to identify the relationship between subjective family class and suicidal ideation and to determine the double mediating effect of social support and sense of coherence on their relationship. Methods: Secondary analysis of data from 2015 Korean Psycho-social Anxiety which was a population-based representative was performed. Double mediating effects of social support and sense of coherence on suicidal ideation were analyzed using the PROCESS macro (model 6) with bootstrapping methods. Results: Subjective family class directly influenced social support (β=.20, p<.001) and sense of coherence (β=.10, p<.001). Subjective family class directly influenced suicide ideation (β=-.08, p<.001). Sense of coherence was directly influenced by social support (β=.28, p<.001). Suicide ideation was indirectly influenced by subjective family class through social support (β=-.22, p<.001) and sense of coherence (β=-.36, p=.001). The size of direct effect of subjective family class on suicide ideation was 0.24 and the total size of indirect effect was 0.12. Conclusion: Intervention to improve social support and sense of coherence is needed to prevent the suicide among adolescents.

• 한국지구과학회지
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• 제35권5호
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• pp.362-374
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• 2014

This study investigated the initial mass function (IMF) and star formation history of high-mass stars in the Small Magellanic Cloud (SMC) using a population synthesis technique. We used the photometric survey catalog of Lee (2013) as the observable quantities and compare them with those of synthetic populations based on Bayesian inference. For the IMF slope (${\Gamma}$) range of -1.1 to -3.5 with steps of 0.1, five types of star formation models were tested: 1) continuous; 2) single burst at 10 Myr; 3) single burst at 60 Myr; 4) double bursts at those epochs; and 5) a complex hybrid model. In this study, a total of 125 models were tested. Based on the model calculations, it was found that the continuous model could simulate the high-mass stars of the SMC and that its IMF slope was -1.6 which is slightly steeper than Salpeter's IMF, i.e., ${\Gamma}=-1.35$.