• 의정연구
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• 제23권2호
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• pp.147-177
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• 2017

한국 선거에서 정치 이념의 역할에 대해 그동안 수많은 연구가 이루어졌으나, 지금까지의 연구들은 예외 없이 횡단면 데이터(cross-sectional data) 분석에 전적으로 의존하였다. 기존의 연구들과 달리 이 연구는 지난 제18대 대통령 선거에서 나타난 이념 투표의 영향을 패널 데이터 분석(panel data analysis)을 통해 보다 엄밀하게 검증한다. 구체적으로, "EAI 총선대선패널조사, 2012"를 이용하여 지난 18대 대통령 선거 시기(2012년 4월 중순-12월 하순)에 정치적이념이 유권자들의 후보 호오도(candidate evaluation)와 후보 선택(vote choice)에 미친 영향을 고정 효과(fixed effects) 분석과 변동 효과(random effect) 분석 등 표준적인 패널 데이터 분석을 통해 살펴보았다. 또한 이념투표의 대표적 설명 모형인 근접성 모형(proximity model)과 방향성 모형(directional change model)을 적용한 결과를 비교 분석하였다. 분석 결과, 지난 18대 대통령 선거에서 진보와 보수의 정치적 이념은 박근혜와 문재인후보에 대한 호오도 및 이들에 대한 지지에 독립적이고 유의미한 영향을 미쳤다고 할 수 있다. 즉, 유권자들은 특정 후보와의 이념적 차이가 크다고 느낄수록 그후보에 대한 지지 확률 및 호오도가 상대적으로 낮아졌다. 그리고 이러한 이념투표의 영향은 근접성 모형보다 방향성 모형에서 상대적으로 뚜렷하게 나타났다.

• 한국공간구조학회논문집
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• 제1권2호
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• pp.111-116
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• 2001

This paper is a study on the elasto-plastic analysis of reinforced concrete precast large panel connections by rigid element spring model. In the analysis of rigid element spring model, each collapsed part or piece of structures at limiting state of loading is assumed to behave like rigid bodies. The present author propose new elements for the improement and expansion of the rigid element spring model. In this study, it is proposed how the rigid element method can be applied to the elesto-plastic analysis of precat large panel connections. Some numerical results of analytical modeling and load displacement curves are shown.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.513-518
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• 2004

KARI(Korea Aerospace Research Institute) has developed smart unmaned aerial vehicle(UAV) since 2002. Smart UAV has tilt rotor configuration which can take off and land vertically. For designing and developing smart UAV, it is necessary to obtain design loads. ARGON which use the panel method is multidisciplinary aircraft design program developed and modified by KARI and TsAGI. Panel method is very useful to obtain aerodynamic loads, so it have been used widely for aircraft loads analysis. For flight loads analysis, we have to prepare regulations and load conditions, and then design aerodynamic panel model, mass model and structure model. In this paper, we introduce the flight loads analysis procedure briefly, and show the smart UAV loads analysis procedure and result using ARGON.

• Steel and Composite Structures
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• 제18권3호
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• pp.693-709
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• 2015

In this article, nonlinear free vibration behaviour of functionally graded spherical panel is analysed. A nonlinear mathematical model is developed based on higher order shear deformation theory for shallow shell by taking Green-Lagrange type of nonlinear kinematics. The material properties of functionally graded material are assumed to be varying continuously in transverse direction and evaluated using Voigt micromechanical model in conjunction with power-law distribution. The governing equation of the shell panel is obtained using Hamilton's principle and discretised with the help of nonlinear finite element method. The desired responses are evaluated through a direct iterative method. The present model has been validated by comparing the frequency ratio (nonlinear frequency to linear frequency) with those available published literatures. Finally, the effect of geometrical parameters (curvature ratio, thickness ratio, aspect ratio and support condition), power law indices and amplitude of vibration on the frequency ratios of spherical panel have been discussed through numerical experimentations.

• Communications for Statistical Applications and Methods
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• 제26권3호
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• pp.315-323
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• 2019

Panel data sets have recently been developed in various areas, and many recent studies have analyzed panel, or longitudinal data sets. Often a dichotomous dependent variable occur in survival analysis, biomedical and epidemiological studies that is analyzed by a generalized linear mixed effects model (GLMM). The most common estimation method for the binary panel data may be the maximum likelihood (ML). Many statistical packages provide ML estimates; however, the estimates are computed from numerically approximated likelihood function. For instance, R packages, pglm (Croissant, 2017) approximate the likelihood function by the Gauss-Hermite quadratures, while Rchoice (Sarrias, Journal of Statistical Software, 74, 1-31, 2016) use a Monte Carlo integration method for the approximation. As a result, it can be observed that different packages give different results because of different numerical computation methods. In this note, we discuss the pros and cons of numerical methods compared with the exact computation method.

• 한국항만경제학회지
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• 제27권3호
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• pp.135-146
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• 2011

오늘날 물류산업은 인수 합병을 통해 거대기업으로 전환되고 있으며, 세계물류시장에서의 경쟁은 점차 치열해지고 있다. 이에 우리나라 정부는 글로벌 경쟁력을 갖춘 물류기업으로 육성하기 위하여 관련기업들의 수직적 또는 수평적 통합을 추진하고 있다. 이의 일환으로 종합물류기업 인증제도를 시행하여 동북아 물류시장의 중심지화 전략을 추구하고 있다. 그런데 종합물류기업의 경쟁력에 있어서 효율성은 대단히 중요한 비중을 차지한다. 이에 본 고는 대형물류기업에 초점을 두고 효율성을 도출한 후 효율성에 영향을 미치는 요인을 식별한다. 토빗분석을 통해 자산, 자본금, 종업원 수의 증가가 효율성을 증가시킨다는 것과 자산의 영향력이 가장 크다는 것을 보인다. 또한 패널분석을 통해 자산, 자본금, 종업원이 매출액 증가에 긍정적 영향을 미친다는 것도 보인다. 이러한 패널분석결과가 장기분석과 부합하는가를 조사하기 위하여 패널공적분벡터를 이용하여 그룹공적분벡터가 양의 부호로 유의하다는 것과 자산과 종업원의 영향력이 별다른 차이를 보이지 않은 패널분석에 비해 장기에서는 상당한 차이를 보인다는 것을 밝힌다.

• Steel and Composite Structures
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• 제19권6호
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• pp.1403-1419
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• 2015

When precast concrete infill panels are connected to steel frames at discrete locations, interaction at the structural interface is neither complete nor absent. The contribution of precast concrete infill panels to the lateral stiffness and strength of steel frames can be significant depending on the quality, quantity and location of the discrete interface connections. This paper presents preliminary experimental and finite element results of an investigation into the composite behaviour of a square steel frame with a precast concrete infill panel subject to lateral loading. The panel is connected at the corners to the ends of the top and bottom beams. The Frame-to-Panel-Connection, FPC4 between steel beam and concrete panel consists of two parts. A T-section with five achor bars welded to the top of the flange is cast in at the panel corner at a forty five degree angle. The triangularly shaped web of the T-section is reinforced against local buckling with a stiffener plate. The second part consists of a triangular gusset plate which is welded to the beam flange. Two bolts acting in shear connect the gusset plate to the web of the T-section. This way the connection can act in tension or compression. Experimental pull-out tests on individual connections allowed their load deflection characteristics to be established. A full scale experiment was performed on a one-storey one-bay 3 by 3 m infilled frame structure which was horizontally loaded at the top. With the characteristics of the frame-to-panel connections obtained from the experiments on individual connections, finite element analyses were performed on the infilled frame structures taking geometric and material non-linear behaviour of the structural components into account. The finite element model yields reasonably accurate results. This allows the model to be used for further parametric studies.

• Communications for Statistical Applications and Methods
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• 제17권3호
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• pp.349-356
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• 2010

The ordinary least squares based estimator of the disturbance variance in a regression model for spatial panel data is shown to be asymptotically unbiased and weakly consistent in the context of SAR(1), SMA(1) and SARMA(1,1)-disturbances when there is measurement error in the regressor matrix.

• 천문학회지
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• 제54권1호
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• pp.9-16
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• 2021

The Ozone Dynamics Investigation Nano-Satellite (ODIN) is a CubeSat design proposed by Chungnam National University as contribution to the CubeSat Competition 2019 sponsored by the Korean Aerospace Research Institute (KARI). The main objectives of ODIN are (1) to observe the polar ozone column density (latitude range of 60° to 80° in both hemispheres) and (2) to investigate the chemical dynamics between stratospheric ozone and ozone depleting substances (ODSs) through spectroscopy of the terrestrial atmosphere. For the operation of ODIN, a highly efficient power system designed for the specific orbit is required. We present the conceptual structural design of ODIN and an analysis of power generation in a sun synchronous orbit (SSO) using two different configurations of 3U solar panels (a deployed model and a non-deployed model). The deployed solar panel model generates 189.7 W through one day which consists of 14 orbit cycles, while the non-deployed solar panel model generates 152.6 W. Both models generate enough power for ODIN and the calculation suggests that the deployed solar panel model can generate slightly more power than the non-deployed solar panel model in a single orbit cycle. We eventually selected the non-deployed solar panel model for our design because of its robustness against vibration during the launch sequence and the capability of stable power generation through a whole day cycle.

• 한국전자파학회논문지
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• 제25권1호
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• pp.47-52
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• 2014

본 논문에서는 대면적 정전식 터치스크린 구동 회로를 설계하기 위하여 여러 가지 터치스크린 패널 구조의 회로 모델을 제안하고, 그 모델의 사용 가능한 주파수 영역을 분석하였다. 터치스크린 패널 한 개 셀의 2D EM 시뮬레이션 결과를 이용한 전체 패널의 circuit 시뮬레이션을 통하여, 23인치 대면적 패널의 가장 긴 채널과 짧은 채널을 5개의 RC 소자의 회로 모델로 근사하였다. EM/circuit 시뮬레이션과 5개 소자의 RC 모델의 S 파라미터 비교를 통해, 5개 소자 모델이 130 kHz까지 10도 이내의 채널 위상 차이를 가지는 것을 확인하였다. 7개 RC 소자를 사용한 모델을 통하여 10도 이내의 채널 위상 차이를 가지는 모델의 주파수 영역을 200 kHz까지 확장하였다.