• 한국항해항만학회지
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• 제37권4호
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• pp.345-350
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• 2013

제한수역에서 측벽부근을 대형선박이 항행할 경우, 측벽으로 인하여 발생하는 유체력이 대형선박의 조종운동에 상당히 크게 영향을 미친다는 것은 잘 알려져 있다. 이 논문에서는 방파제형상을 하고 있는 측벽 부근을 대형선박이 항행하는 경우, 선박과 방파제 형상간의 간섭력 추정을 위해 세장체 이론을 토대로 한 계산 방법을 적용하였으며, 선박에 미치는 측벽의 영향을 파악하기 위하여 방파제길이, 방파제와 선박간의 거리 및 수심을 변수로 하여 선박과 측벽과의 간섭력을 수치 계산하였다.

• 한국의류학회지
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• 제32권2호
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• pp.190-200
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• 2008

The purposes of this study were to identify brand equity factors influencing brand preference and to investigate the effects of preference and other factors on brand performance of domestic and imported fashion accessary(handbag, shoes, purse, etc.) brands. A total of 300 women aged between 20 and 49 years were surveyed during the month of September, 2006, on 2 domestic brands and 2 imported brands that were well-known to consumers. The data were analyzed with factorial analysis, multiple regression analysis, ANOVA, Cronbach's ${\alpha}$, etc., using the SPSS 10.0. The result of research showed: 1) Four factors of brand equity were identified: quality, awareness, image, and trust. 2) Quality, awareness, price acceptability, distribution proximity, and brand performance of the domestic brands were higher than those of the imported brands. But brand preference of the imported brands was higher than that of the domestic brands. 3) Brand preference of the domestic brands was affected by quality, awareness, image, and trust. And brand performance of the domestic brands was affected by appropriateness, brand preference, and distribution proximity. 4) Brand preference of the imported brands was affected by image, quality, awareness, and trust. And brand performance of the imported brands was affected by price acceptability, appropriateness, and distribution proximity.

• 산업경영시스템학회지
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• 제40권2호
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• pp.78-91
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• 2017

In this study, we conducted a comparative study on user's perception and behavior on public system service (PSS) using institutionalism theory and MGA (multi-group analysis) methodology. In particular, this study focuses on how institutional isomorphism is applied to public system services and how MGA can be implemented correctly in a variance based SEM (structural equation model) such as PLS (partial least square). A data set of 496 effective responses was collected from pubic system users and an empirical research was conducted using three segmented models categorized by public proximity theory (public firms = 113, government contractors = 210, private contractors = 173). For rigorous group comparisons, each model was estimated by the same indicators and approaches. PLS-SEM was used in testing research hypotheses, followed by parametric and non-parametric PLS-MGA procedures in testing categorical moderation effects. This study applied novel procedures for testing composite measurement invariance prior to multi-group comparisons. The following main results and implications are drawn : 1) Partial measurement invariance was established. Multi-group analysis can be done by decomposed models although data can not be pooled for one integrated model. 2) Multi-group analysis using various approaches showed that proximity to public sphere moderated some hypothesized paths from quality dimensions to user satisfaction, which means that categorical moderating effects were partially supported. 3) Careful attention should be given to the selection of statistical test methods and the interpretation of the results of multi-group analysis, taking into account the different outcomes of the PLS-MGA test methods and the low statistical power of the moderating effect. It is necessary to use various methods such as comparing the difference in the path coefficient significance and the significance of the path coefficient difference between the groups. 4) Substantial differences in the perceptions and behaviors of PSS users existed according to proximity to public sphere, including the significance of path coefficients, mediation and categorical moderation effects. 5) The paper also provides detailed analysis and implication from a new institutional perspective. This study using a novel and appropriate methodology for performing group comparisons would be useful for researchers interested in comparative studies employing institutionalism theory and PLS-SEM multi-group analysis technique.

• 한국자기학회지
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• 제22권2호
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• pp.66-72
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• 2012

강자성 초전도체의 발견은 상극으로 알려진 강자성과 초전도성이 어떻게 상호작용하여 조화롭게 공존하는지에 대한 학문적인 연구뿐만 아니라 새로운 기술적인 응용을 위한 광범위한 탐구를 이끌고 있다. 본 해설논문에서는 강자성 초전도체에 대한 이해를 돕기 위하여, 먼저 초전도체의 쿠퍼쌍을 깨뜨리는 강한 자기장의 궤도 효과와 상자성 효과에 대하여 설명한다. 자기장의 이러한 효과 이외에도 초전도체/강자성체 복합 구조의 계면에서 발생하는 근접 효과에 의해 단일상 쿠퍼쌍은 강자성체를 지나가는 동안 불안정하여 아주 짧은 침투깊이를 가진다. 그러나 쿠퍼쌍이 홀-진동수 삼중상인 경우 안정되고 긴 유효길이를 가지게 되는데, 새로운 스핀 전자소자로서의 개발을 위해 그 연구의 중요성이 높아지고 있다. 마지막으로 다양한 강자성 초전도체와 양자구속효과에 의해 두 성질이 공존하는 저차원의 물질들을 소개한다.

• 감성과학
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• 제21권2호
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• pp.73-88
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• 2018

본 연구는 손과 가까운 시각 정보의 처리적 특성이 과제전환에 미치는 영향을 살펴보기 위해 수행되었다. 최근 연구들은 손과 가깝게 제시된 정보에 대한 인지통제가 향상됨을 보고하고 있다. 이러한 인지통제 향상효과를 손 근접성과 주의의 관계를 통해 규명하고자 두 번의 실험을 실시하였다. 그 결과 과제전환 수행에서 단서와 목표자극의 감각양상에 따라 손 근접성의 효과가 달라짐을 관찰할 수 있었다. 첫 번째 실험에서 손에 근접한 자극에 대한 전환비용의 감소가 관찰되었다. 선행 연구들에서 전환비용의 감소원인으로 지목되었던 특징결합 문제를 제외시켰을 경우에도 동일한 결과가 관찰되었다. 즉, 손 근접성이 전환비용을 감소시켰음을 검증할 수 있었다. 두 번째 실험에서는 손 근접성과 감각양상의 상호작용이 전환비용에 미치는 영향을 살펴보기 위해 수행되었다. 과제전환에서 목표자극은 시각으로 단서는 시각 또는 청각으로 제시하였고, 단서의 준비성 효과를 관찰하기 위해 단서-목표자극 간격을 조변하였다. 연구 결과 손에 근접한 시각 단서는 과제 준비 시간을 단축시켜 전환비용을 감소시켰으나, 청각 단서의 경우 손에 근접할 때 오히려 과제 준비 시간이 더 오래 걸렸다. 시각 단서의 결과는 손에 근접한 시각 정보에 대한 신속한 주의정향으로 인한 이득으로 설명될 수 있다. 반면에 청각 단서에서 나타난 손실은 청각 단서와 시각 자극 간의 감각 간 전환이 손 근접성의 주의 범위 고정 효과로 인해 방해된 결과로 해석될 수 있다. 마지막으로 손 근접성의 주의효과로 인해 달라지는 전환비용에 대해 논의하였다.

• 한국환경과학회지
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• 제25권10호
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• pp.1349-1368
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• 2016

Concentrations of fine particulate matter ($PM_{2.5}$) and several of its particle constituents measured outside homes in Houston, Texas, and Los Angeles, California, were characterized using multiple regression analysis with proximity to point and mobile sources and meteorological factors as the independent variables. $PM_{2.5}$ mass and the concentrations of organic carbon (OC), elemental carbon (EC), benzo-[a]-pyrene (BaP), perylene (Per), benzo-[g,h,i]-perylene (BghiP), and coronene (Cor) were examined. Negative associations of wind speed with concentrations demonstrated the effect of dilution by high wind speed. Atmospheric stability increase was associated with concentration increase. Petrochemical source proximity was included in the EC model in Houston. Area source proximity was not selected for any of the $PM_{2.5}$ constituents' regression models. When the median values of the meteorological factors were used and the proximity to sources varied, the air concentrations calculated using the models for the eleven $PM_{2.5}$ constituents outside the homes closest to influential highways were 1.5-15.8 fold higher than those outside homes furthest from the highway emission sources. When the median distance to the sources was used in the models, the concentrations of the $PM_{2.5}$ constituents varied 2 to 82 fold, as the meteorological conditions varied over the observed range. We found different relationships between the two urban areas, illustrating the unique nature of urban sources and suggesting that localized sources need to be evaluated carefully to understand their potential contributions to $PM_{2.5}$ mass and its particle constituents concentrations near residences, which influence baseline indoor air concentrations and personal exposures. The results of this study could assist in the appropriate design of monitoring networks for community-level sampling and help improve the accuracy of exposure models linking emission sources with estimated pollutant concentrations at the residential level.

• Progress in Superconductivity
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• 제4권1호
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• pp.64-67
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• 2002

The attenuation of millimeter waves (70-100 ㎓) propagating along Josephson Junction stripline had been measured by pattern recognition near gap voltage and proximity current bump. Test series arrays of 2000, 3000, and 4000 Josephson junctions with the area of $12\mu\textrm{m}$$\times$ $38\mu\textrm{m}$ had two sub-arrays with 50 Junctions at both ends. The arrays were fabricated with and without applying a plasma nitridation process to Nb ground plane. The effects of a nitridationprocess measured by the pattern recognition near gap voltage and proximity current bump were about 1.3-1.7 ㏈ and 1.6-1.8 ㏈, respectively. This means that the last sub-arrays with a nitridation process receive 26-34% more power than those without a nitridation process.

• Wind and Structures
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• 제1권3호
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• pp.271-284
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• 1998

This paper uses the numerical simulation to investigate the interference effect of 3-D turbulent flow around two high rise buildings in proximity at the different relative heights, gaps, and wind velocities. The computer program used to carry out the simulation is based on the control volume method and the SIMPLEST algorithm. The ${\kappa}-{\varepsilon}$ model was used to simulate turbulence effects. Since the contracted flow between two adjacent buildings enhances the strength of vortex shedding from the object building, the pressure coefficient on each side wall of the object building is generally increased by the presence of apposed building. The effect is increased as the relative height or the gap between the two buildings decreases. The velocity on the vertical center line between two buildings is about 1.4 to 1.5 times the upstream wind velocity.

• Corrosion Science and Technology
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• 제15권1호
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• pp.6-12
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• 2016

Flow-Accelerated Corrosion (FAC) is a well-known degradation mechanism that attacks the secondary piping in nuclear power plants. Since the Surry Unit 2 event in 1986, most nuclear power plants have implemented management programs to deal with damages in carbon and low-alloy steel piping. Despite the utmost efforts, damage induced by FAC still occurs in power plants around the world. In order to predict FAC wear, some computer programs were developed such as CHECWORKS, CICERO, and COMSY. Various data need to be input to these programs; the chemical composition of secondary piping, flow operating conditions and piping geometries. CHECWORKS, developed by the Electric Power Research Institute (EPRI), uses a geometry code to calculate geometry effects. Such a relatively simple geometry code is limited in acquiring the accuracy of FAC prediction. Recently, EPRI revisited the geometry code with the intention of updating it. In this study, numerical simulations were performed for two adjacent $90^{\circ}$ elbows and the results were analysed in terms of the proximity effect between the two adjacent elbows.

• 오토저널
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• 제8권1호
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• pp.52-61
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• 1986

An iterative viscous-potential flow procedure has been developed and used to predict aerodynamic characteristics of automobiles in ground proximity. The method is capable of predicting the effects of separated flows. The viscous-potential flow iteration procedure provides the connection between potential flow, boundary layer and wake modules. The separated wake is modeled in the potential flow analysis by thin sheets across which exists a jump in velocity potential. The ground effect is properly accounted for by placing a body image in the potential flow calculation. The agreement between theory and experiment is good and, thus, demonstrates that the method can be used in the preliminary design stage.