• Structural Engineering and Mechanics
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• 제38권4호
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• pp.479-501
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• 2011

Even though fiber reinforced polymer (FRP) has been widely used as a retrofitting material, the FRP behavior and effect in FRP retrofitted structure under blast loading, impulsive loading with instantaneous time duration, has not been accurately examined. The past studies have focused on the performance of FRP retrofitted structures by making simplifications in modeling, without incorporating accurate failure mechanisms of FRP. Therefore, it is critical to establish an analytical model that can properly consider the specific features of FRP material in evaluating the response of retrofitted concrete structures under blast loading. In this study, debonding failure analysis technique for FRP retrofitted concrete structure under blast loading is suggested by considering FRP material characteristics and debonding failure mechanisms as well as rate dependent failure mechanism based on a blast resisting design concept. In addition, blast simulation of FRP retrofitted RC panel is performed to validate the proposed model and analysis method. For validation of the proposed model and analysis method, the reported experimental results are compared with the debonding failure analysis results. From the comparative verification, it is confirmed that the proposed analytical model considering debonding failure of FRP is able to reasonably predict the behavior of FRP retrofitted concrete panel under blast loading.

• KDI Journal of Economic Policy
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• 제27권2호
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• pp.123-154
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• 2005

본 논문은 우리나라 가계의 내구재 소비결정에 관한 실증분석이다. 기존의 연구에 의하면 표준적인 항상소득가설은 비내구재 소비에 대해서는 비교적 높은 설명력을 나타내지만 내구재 소비에 대해서는 설명력이 거의 없는 것으로 나타난다. 본 연구에서는 이러한 항상소득가설의 대안으로서 조정비용의 존재를 허용하는 (S, s)모형을 고려한다. (S, s)모형에 의하면 내구재 소비는 조정비용 때문에 매 순간 최적 수준을 유지하지는 못하지만, 일단 조정이 이루어지는 경우에는 최적 수준을 달성할 것으로 예상된다. 본 논문은 (S, s)모형의 이러한 예측을 검증하기 위하여 한국가구 패널조사자료에 나타난 각 가계의 내구재 소비와 비내구재 소비의 관계 및 내구재 소비의 기간 간 변화를 살펴본다. 분석결과에 의하면 표준적인 항상소득가설은 기각되는 반면 (S, s)모형은 대체로 자료와 일치하는 것으로 나타난다.

• 한국컴퓨터정보학회논문지
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• 제26권4호
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• pp.181-188
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• 2021

본 연구의 목적은 패널자료의 분석을 통해 청소년의 학교생활적응과 생활만족도 간의 인과관계를 파악함으로써 학교생활적응 및 생활만족도의 제고와 관련된 함의를 얻는 것이다. 연구목적의 달성을 위해 한국아동·청소년패널조사(2010-2016) 초4패널의 제1차 내지 제7차 자료를 사용하여 학교생활적응과 생활만족도 간의 관계를 자기회귀 교차지연 모형을 적용하여 검정하였다. 연구결과는 다음과 같았다. 첫째, 조사대상 기간에 걸쳐 이전 시점의 학교생활적응은 이후 시점의 학교생활적응을 안정적으로 예측하였다. 둘째, 조사대상 기간에 걸쳐 이전 시점의 생활만족도는 이후 시점의 생활만족도를 안정적으로 예측하였다. 셋째, 조사대상 기간에 걸쳐 이전 시점의 학교생활적응은 이후 시점의 생활만족도를 안정적으로 예측하였으나 그 반대 방향의 인과성은 유의하지 않았다. 끝으로, 청소년의 학교생활적응과 생활만족도 증진을 위한 함의를 제시하였다.

• 한국산업융합학회 논문집
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• 제27권4_2호
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• pp.961-972
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• 2024

As the global elderly population rapidly increases, the mental health of the elderly, particularly depression, has emerged as a significant social issue. This study analyzes the various factors influencing depression in the elderly based on the ICF model. Utilizing data from the Korea Welfare Panel Study, the study identifies the types of changes in depression among individuals aged 65 and older and examines the factors influencing these changes. This longitudinal secondary data analysis research uses the most recent three years of data (2021-2023) from the Korea Welfare Panel. The study sample consisted of 965 elderly individuals, and a latent class growth model was applied to identify the types of depression changes, while a multinomial logistic regression analysis was conducted to analyze the influencing factors. The analysis revealed that elderly depression could be categorized into four types: high-level decrease, high-level maintenance, low-level increase, and low-level maintenance. Main influencing factors included gender, age, education, poverty, social trust, social relationships, participation in economic activities, participation in religious activities, and health status. Particularly, social relationships and health status were significant factors affecting the types of depression changes. To mitigate depression in the elderly, a multifaceted approach considering both individual characteristics and social relationships and health status is required. The study suggests the development of community-based programs and trust-building activities at the community level to maintain and strengthen the social relationships of the elderly. These findings can serve as important foundational data for policies and practices aimed at improving the mental health of the elderly.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 가을 학술발표회 논문집
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• pp.105-110
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• 2002

This paper proposes an analytical method to predict the behavior of reinforced concrete beams subjected to reversed cyclic loading. The proposed method is based on the compatibility aided truss model and adopts the stress vs. strain curve of concrete which considers the softening effects. This model Is verified by comparing to the six reinforced concrete panel tests.

• 대한기계학회논문집A
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• 제29권2호
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• pp.350-359
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• 2005

Finite element method is a very effective method to simulate the forming processes with good prediction of the deformation behaviour. For the finite element modeling of sheet mental forming the accurate die model is required. Among finite element method, the static-implicit finite element method is applied effectively to analyze real-size auto-body panel stamping processes, which include the forming stage. This study is about analyzing the stamping process problems by using AutoForm commercial software which used static-implicit method. According to this study, the results of simulation will give engineers good information to access the die design of optimization.

• 노동경제논집
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• 제31권2호
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• pp.103-128
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• 2008

본 연구는 "한국노동패널조사" 자료를 사용하여 노동조합이 임금에 미치는 효과를 패널 분석하였다. 횡단면 분석을 통하여 구한 노동조합이 임금상승에 미치는 효과는 약 4.6%로 추정되었다. 고정효과 모델을 통하여 추정된 노조의 임금상승효과는 약 2.1%로 상당히 그 효과가 감소하였음을 알 수 있다. 따라서 보이지 않는 근로자의 특성과 노조가 있는 기업에 종사하며 노동조합에 가입하는 의사결정과 양(+)의 상관관계가 존재함을 유추해 볼 수 있으며 기존의 횡단면 분석의 연구 결과가 상당 부분 상향 편의되었음을 유추해 볼 수 있다.

• 품질경영학회지
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• 제41권4호
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• pp.601-610
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• 2013

Purpose: The purpose of this paper is to analyze the relationship between R&D investment and growth rate of manufacturing firms in Incheon. Methods: The balanced panel data of 246 firms which have existed for the period 2001-2012 are constructed. As a method of analysis, fixed effects panel data model is used. Results: There is a one year lag in the relationship between R&D intensity and the subsequent sales growth of firms and its relation depends on the firms' characteristics. Conclusion: We suggest the emphasis on R&D investment for firms' growth and the differentiated R&D program based on firm size. This article has the limitation that various types of R&D investment cannot be included in this analysis.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1998년도 춘계학술대회논문집; 용평리조트 타워콘도, 21-22 May 1998
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• pp.634-642
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• 1998

This paper deals with the analytical model of an elastic porous material in sound transmission loss of a double panel with fiber glasses. From the parametric analysis, it is concluded that the boundary condition, which is concerned to the contact between the skin panel and core materials, does not have much influence on sound transmission loss of a double panel with fiber glasses, and material properties of the porous material become, however, important factors to mass-spring-mass resonance. The comparisons of the prediction with the measurement of sound transmission loss of walls show good agreement between the two values.

• Structural Engineering and Mechanics
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• 제52권6호
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• pp.1209-1224
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• 2014

In Current paper, the voltages of patches optimization are carried out for minimizing the power consumption of piezoelectric patches and maximum vertical displacement of symmetrically FML panels using the modified multi-objective Elitist-Artificial Bee Colony (E-ABC) algorithm. The voltages of patches, panel length/width ratios, ply angles, thickness of metal sheets and edge conditions are chosen as design variables. The classical laminated plate theory (CLPT) is considered to model the transient response of the panel, and numerical results are obtained by the finite element method. The performance of the E-ABC is also compared with the PSO algorithm and shows the good efficiency of the E-ABC algorithm. To check the validity, the transient responses of isotropic and orthotropic panels are compared with those available in the literature and show a good agreement.