• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2008년도 추계 학술발표회
• /
• pp.1518-1525
• /
• 2008

This paper concerns optimum design of 2-Arch tunnel. A 2-Arch tunnel adopted in a subway tunnel construction site is considered in this study. A calibrated 3D finite element model was adopted to conduct a parametric study on the lagged distance between left and right tunnel faces. The results of analysis were examined to determine optimum lagged distance for minimizing the interaction between the left and right tunnels. The results indicated that the shotcrete lining stress and the center pillar load are more influenced by the second tunnel excavation than the tunnel deformation. Also shown is that a lagged distance of 20m is sufficient to minimize the interaction between two tunnels. Fundamental mechanism of 2-arch tunnel was also investigated based on the results.

• 한국터널지하공간학회 논문집
• /
• 제11권3호
• /
• pp.255-264
• /
• 2009

본 연구에서는 2-Arch 터널의 3차원 거동 메카니즘에 관한 내용을 다루었다. 이를 위해 도심지 지하철에 적용된 2-Arch 터널을 고려하였으며 3차원 유한요소해석을 수행하여 좌우 터널의 이격거리, 지반조건, 토피고 등에 대한 매개변수연구를 실시하였다. 해석결과 토대로 다양한 조건에 대한 터널 천단침하 및 쇼크리트 응력, 중앙기둥 작용하중 등을 중점으로 분석하였으며, 그 결과를 토대로 좌우 터널 이격거리, 지반조건, 토피고에 따른 2-Arch 터널의 거동 메카니즘을 고찰하였다. 그 결과 숏크리트 라이닝 응력 및 중앙 기둥 작용하중은 후행터널 시공에 큰 영향을 받는 것으로 나타났으며 터널관통지층이 취약할 경우 후행터널이 선행터널의 거동에 영향을 미치는 영향거리가 증가하는 것으로 분석되었다. 본 논문에서는 해석 결과를 토대로 2-Arch 터널의 시공중 변위 및 숏크리트 라이닝 응력 변화 경향에 대한 구체적인 내용을 기술하였다.

• 한국철도학회논문집
• /
• 제7권2호
• /
• pp.155-162
• /
• 2004

In order to account for a price variation of apartment that places near a newly constructed subway station, a spatial hedonic model was developed to examine spacial characteristics that affect a purchasing price of an apartment using a White Estimator. In particular, the paper aims to examine various effects of subway 7 construction on an apartment price in Seoul Metropolitan Area. As explanatory variables, an apartment size, distance to a closest subway station, distance to the Central Business District (CBD) of Seoul, the number of years after building, and a lagged variable of the apartment purchasing price were used. The lagged variable plays a role of representing a spatial weighted average of previous prices of other apartments that locate within 3 km from the apartment. For a precise study, an entire sample was divided into two sets, southern area and southwestern area of Seoul, and two different spatial hedonic models were estimated. Not only before and after analysis, but also with and without analysis were conducted to compare with different effects of the spatial characteristics of two areas. The results show that before the construction of the subway 7, the prices of the apartments in the southern area were more sensitive to the apartment size, the distance to a closest subway station, the distance to the CBD, and the prices of the other apartments locating within 3km rather than those in the southwestern area. After the construction, on contrast, it is found that the apartment purchasing prices in the southwestern area are more sensitive than those in the southern area due to people's expectation regarding a new development around the subway station. In addition, the prices of the apartments locating closely with a transfer station are more likely to go up by increase in the apartment size, the distance to the station, and the prices of the other apartments within 3 km. Compared with the negative effects of the distance to the station on the prices in the other models, the positive effect of the distance to the transfer station might be caused by the characteristics of commercial area in which people are not likely to live.

• Communications for Statistical Applications and Methods
• /
• 제29권4호
• /
• pp.471-486
• /
• 2022

Autoregressive moving average (ARMA) models involve nonlinearity in the model coefficients because of unobserved lagged errors, which complicates the likelihood function and makes the posterior density analytically intractable. In order to overcome this problem of posterior analysis, some approximation methods have been proposed in literature. In this paper we first review the main analytic approximations proposed to approximate the posterior density of ARMA models to be analytically tractable, which include Newbold, Zellner-Reynolds, and Broemeling-Shaarawy approximations. We then use the Kullback-Leibler divergence to study the relation between these three analytic approximations and to measure the distance between their derived approximate posteriors for ARMA models. In addition, we evaluate the impact of the approximate posteriors distance in Bayesian estimates of mean and precision of the model coefficients by generating a large number of Monte Carlo simulations from the approximate posteriors. Simulation study results show that the approximate posteriors of Newbold and Zellner-Reynolds are very close to each other, and their estimates have higher precision compared to those of Broemeling-Shaarawy approximation. Same results are obtained from the application to real-world time series datasets.

• 가정과삶의질연구
• /
• 제34권6호
• /
• pp.69-85
• /
• 2016

This study examined bidirectional associations between intergenerational residential proximity and older parents' mental and physical health. The data were drawn from first three waves of the Korean Longitudinal Study of Ageing (KLoSA, 2006, 2008, 2010), a nationally representative sample of adults 45 years or older and their spouses. The analytic sample consisted of 2,391 parents aged 60 years or older with at least one child who were continuously married between 2006 and 2010. Intergenerational residential proximity was measured with travel time between parental residence and that of the oldest of the continuously married children. For statistical analysis, autoregressive cross-lagged models were estimated using AMOS. Findings suggest that intergenerational residential proximity may have bidirectional associations with functional health, and an unidirectional association with life satisfaction. Specifically, a closer distance to a married son or daughter reported in 2006 was associated with poorer functional health of the parent in 2008. An older parent's greater number of functional limitations in 2006 was also related to a closer residential proximity to the married child in 2008. A greater residential proximity to a son, but not a daughter, reported in 2006 was associated with a higher level of parental life satisfaction in 2008. Overall, results suggest that having nearby a married adult child, particularly a married son, may help maintain parental health.

• Structural Engineering and Mechanics
• /
• 제75권5호
• /
• pp.571-583
• /
• 2020

Permeation grouting is of great significance for consolidating geo-materials without disturbing the original geo-structure. To dip into the filtration-induced pressure increment that dominates the grout penetration in permeation grouting, nonlinear filtration coefficients embedded in a convection-filtration model were proposed, in which the volume of cement particles in grout and the deposited particles of skeleton were considered. An experiment was designed to determine the filtration coefficients and verify the model. The filtration coefficients deduced from experimental data were used in simulation, and the modelling results matched well with the experimental ones. The pressure drop revealed in experiments and captured in modelling demonstrated that the surge of inflow pressure lagged behind the stoppage of flow channels. In addition, both the consideration of the particles loss in liquid grout and the number of filtrated particles on pore walls presented an ideal trend in filtration rate, in which the filtration rate first rose rapidly and then reached to a steady plateau. Finally, this observed pressure drop was extended to the grouting design which alters the water to cement (W/C) ratio so as to alleviate the filtration effect. This study offers a novel insight into the filtration behaviour and has a practical meaning to extend penetration distance.

• 한국ITS학회 논문지
• /
• 제18권5호
• /
• pp.64-78
• /
• 2019

본 논문은 공간 상관성을 고려하여 서울의 택시통행에 영향을 미치는 요인을 분석한 것으로 택시의 GPS 자료를 이용하였다. 먼저 이들 자료를 이용하여 택시통행의 평균 통행시간, 평균 통행거리, 시공간적 분포 등의 통행특성을 분석하였다. 분석결과, 상당수의 택시통행이 평일 오전 첨두(8-9시)와 심야(0-1시) 시간대에 집중하는 것으로 나타났으며, 평균 통행거리와 통행시간은 각각 5.9km와 13분으로 나타났다. 이는 택시가 주로 단거리 통행수단이나 심야에 대중교통의 대체수단으로 활용되고 있음을 보여주고 있다. 다음으로 Moran's I 검정을 통해 교통존 기반의 택시통행들이 공간적으로 상관성이 있음을 규명하였다. 따라서 이를 고려한 택시통행에 대한 공간회귀모형(공간시차모형과 공간오차모형)을 추정하였으며, 인구사회 변수(가구수, 고령자수, 여성인구비, 자동차대수 등), 교통서비스 변수(지하철역수, 버스 정류장수 등), 토지이용 변수(인구밀도, 고용밀도, 주거면적 등) 등을 독립변수로 고려하였다. 모형분석 결과 이들 변수들이 통계적으로 유의하게 택시통행에 영향을 미치는 것으로 나타났다.

• 대한장애인치과학회지
• /
• 제7권1호
• /
• pp.1-10
• /
• 2011

The purpose of this study was to examine the general attitude of dental hygiene students toward the disabled and their oral care in an effort to improve their awareness of the disabled and their accessibility to them and suggest some of the right directions for dental hygiene education related to dental treatment for the disabled. The subjects in this study were dental hygiene students at three different colleges located in South Jeolla Province. The general attitude of the selected students toward the disabled and their oral care were investigated from November 1 to December 20, 2007. The findings of the study were as follows: When their general attitude toward disabled people was checked, they agreed the most that there was nothing that the disabled lagged behind nondisabled people. Those who felt the need for that took a more positive attitude in eight items, and the differences between them and the others were significant. Whether they were cognizant of the necessity of dental treatment education for the disabled made the most significant differences to each variable of their attitude toward the oral care of disabled people, and those who were aware of the necessity showed a more positive attitude in five items. The differences between them and the others were significant. The findings of the study illustrated that the dental hygiene students took a relatively favorable attitude toward disabled people's oral health care, and that they hardly felt a sense of distance to them. So it can be predicted that they will get to take the right attitude to them in the future. Yet the dental hygiene curriculum should give more weight to dental treatment education for the disabled and offer more relevant information, since they didn't get high scores on positive attitude.

• 한국지역지리학회지
• /
• 제4권1호
• /
• pp.77-98
• /
• 1998

본 연구는 제조업 중에서도 지역성장 및 연관산업에 대한 파급효과가 가장 큰 부문인 자동차 산업을 대상으로 새로운 조립공장 입지가 지역경제의 성장 및 발전에 미치는 영향을 경계지리학적 관점에서 논의했다. 우리 나라의 대표적 신산업지구로 발전하고 있는 광양만권의 율촌 산업단지를 사례로, 한국 최대의 자동차 조림기업인 현대자동차의 새로운 조립공장 입지가 광주 전남의 자동차산업 전반에 어떠한 영향을 미칠 것인지, 그리고 보다 미시적 수준에서 광양만권에 어떠한 파급효과를 초래할 것인지 탐색해보고자 했다. 노동집약적 특성과 자본 및 기술집약적 특성을 동시에 지니는 자동차 조립 및 부품생산 부문을 대상으로 첫째, 조립부문-부품생산부문의 공간적 비공간적 연계 특성을 규명하고 둘께, 광주 전남지역 자동차산업의 현 주소 및 이에 대한 신설 조립공장의 파급효과를 분석하며 셋째, 신설 조립공장 입지에 따른 광양만권 역내의 부품산업 발전 가능성을 전망함으로써 지역개발의 파급효과를 극대화할 수 있는 방안을 모색해보고자 하는 것이 본 연구의 목적이다.

• 한국산림과학회지
• /
• 제79권2호
• /
• pp.115-126
• /
• 1990

본(本) 연구(硏究)는 두 지역간(地域間)의 솔잎혹파리에 관한 서로 다른 유충(幼蟲)의 주광성(走光性), 우화율(羽化率), 성비(性比), 그리고 충영형성율(蟲癭形成率)을 찾고자 수행(遂行)하였다. 북쪽에서는 피해(被害)가 가장 심한 구성성분(構城成分)을 남쪽에서는 최초(最初)의 발생지(發生地)였던 무안지역(務安地域)을 선택, 이 두 지역(地域)에서 가져온 유충(幼蟲)을 원광대학교(圓光大學校) 곤충학(昆蟲學) 실험실(實驗室)에 옮겨 월동(越冬)을 시켰다. (1) 우집단간(雨集團間) 성숙유충(成熟幼蟲)의 크기에는 차이(差異)가 인정(認定)되지 않았고, (2) 주광성(走光性)에 있어서는 무안집단(務安集團)이 구성집단(構成集團)보다 높은 조도(照度)와 온도(溫度)에 있어서 더 민감(敏感)한 반응(反應)을 보였다. (3) 우화량(羽化量)에 있어서는 무안집단(務安集團)이 구성집단(構成集團)의 그것에 비해서 3배(倍)가량 높았으며, (4) 우화기간(羽化其間)에도 차이(差異)가 인정(認定)되었다. (5) 충영형성율(蟲癭形成率)은 두 집단간(集團間)에 큰 차이(差異)가 없었다. (6) 성별우화수(性別羽化數)에 있어서는 두 집단(集團) 모두 자충(雌蟲)이 웅충(雄蟲)에 비해서 훨씬 더 높게 나타났다. (7) 솔잎혹파리 기생봉류(寄生蜂類)에 대한 관찰내용(觀察內容)이 설명(說明)되었고, (8) 두 집단(集團)의 이질성(異質性)의 일단(一端)이 밝혀진 것으로 사료(思料)된다.