• Journal of the Korea Society of Computer and Information
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• v.26 no.5
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• pp.77-86
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• 2021

This study aims at exploring the change of the total fertility rate(TFR) in regional level and analysing what different effects the local labor market and housing market have on the change of TFR. Previous studies have emphasized that the job and housing issues of the youth are structural factors on the decline of TFR. However, considering that youth problem is variant in local level, the relationship of job and housing issues with TFR could be different in local level. This study analyses what effects the situation of local labor market and housing market have on the TFR from 2012 to 2018 in regional level. The result is that the employment and housing factors have different effects on capital areas and non-capital areas. While the high cost of housing has negative effects on TFR in capital areas, it has rather positive effects in non-capital areas. However, labor market variables have statistically insignificant effects on TFR.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.05a
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• pp.154-155
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• 2016

Although there is an increase in demand for free-form buildings, there are several problems such as increased cost and duration and decreased constructability arising from difficult member production and installation. To solve these problems, a technology to produce free-form panels using CNC machine was developed. According to the technology, the information on free-form buildings designed is delivered to the CNC machine, a form is shaped using the delivered information and free-form concrete panels are produced using the form. The limited construction site, duration and project cost as well as interferences with other work types should be considered upon in-situ production of free-form concrete panels. Thus, the purpose of this study is to conduct a base study on in-situ production layout of free-form concrete panels by system dynamics. With this study, we will discover the causal relationship of influence factors on in-situ production of free-form concrete panels, and improved productivity is expected through the production layout.

• Land and Housing Review
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• v.14 no.1
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• pp.33-46
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• 2023

This study investigated price factors for large apartment complexes in Seoul during the COVID-19 pandemic and compared Gangnam and non-Gangnam areas, which have been recognized as heterogeneous markets. We find that the change in apartment prices in large-scale complexes did not significantly affect the individual characteristics of apartments, unlike previous studies, but was affected by macroeconomic variables such as interest rates and money. On the other hand, considering the units of the interest rate and total monetary volume variables, the effects of two variables on the apartment sales price is significantly high. In addition, the Gangnam area model analysis shows that apartment prices are greatly affected by interest rates and currency volume, and, the non-Gangnam area model analysis shows that apartment prices are greatly affected by interest rates and currency volume, but the degrees are different from the Gangnam area model. Overall, our study shows that interest rates and money supply were the main factors of apartment price changes, but apartment prices in non-Gangnam areas are more sensitive to changes in interest rates and money supply.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.35 no.3
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• pp.141-148
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• 2022

In this study, the structural behavior of reinforced concrete members under simultaneous axial and blast loads was analyzed. Nonlinear dynamic analysis verification was performed using the experimental data of panels under fundamental blast load as well as those of reinforced concrete columns subjected to axial and blast loads. Because Autodyn is a program designed only for dynamic analysis, an analysis process is devised to simulate the initial stress state of members under static loads, such as axial loads. A total of 80 nonlinear dynamic finite element analysis procedures were conducted by selecting parameters corresponding to axial load ratios and scaled distances ranging 0%~70% and 1.1~2.0 (depending on the equivalent of TNT), respectively. The structural behavior was compared and analyzed with the corresponding degree of damage and maximum lateral displacement through the changes in axial load ratio and scaled distance. The results show that the maximum lateral displacement decreases due to the increase in column stiffness under axial loads. In view of the foregoing, the formulated analysis process is anticipated to be used in developing blast-resistant design models where structural behavior can be classified into three areas considering axial load ratios of 10%~30%, 30%~50%, and more than 50%.

• Journal of the Korean Geotechnical Society
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• v.17 no.6
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• pp.163-171
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• 2001

It is important to pay careful attention to the backfill construction for the structural integrity of concrete box culvert. To increase the structural integrity of culvert good compaction by the dynamic compaction roller with big capacity is as effective as good backfill materials. However structural distress of the culvert could be occurred due to the excessive earth pressure by great dynamic compaction load. In this study, two box culverts were constructed with change compaction materials and construction methods. Two type of on-site soils such as subbase and subgrade materials were used as backfill materials. In most case, dynamic compaction rollers with 11 to 12 ton weights were used and vibration frequency were applied from 2000 to 2500 rpm for the great compaction energy. Backfill compactions with good quality soils were carried out to examine the effect of cushions on dynamic lateral soil pressure. Expanded polystyrene (EPS) and rubber of tire were adapted as cushion materials and they are set on the culverts before backfill construction. This paper presents the main results on the characteristics of dynamic earth pressures. Test result indicates that the amounts of increased dynamic pressures are affected with backfill materials, depth of pressure cell, and compaction condition. The earth pressure during compaction can give harmful effect to box culvert because the value of dynamic earth pressure coefficient $(\DeltaK_{dyn}=\DeltaK\sigma_h\DeltaK\sigma_v)$ during compaction is greater than that of static condition. It was observed that cushion panels of EPS(t=10cm) and rubber(t=5cm) are effective to mitigate dynamic lateral pressure on the culverts.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.12
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• pp.7134-7147
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• 2014

This study examined one of the contemporary issues that may be interesting to academics and practitioners regarding the driving force of the growth rate for the firms belonging to the chaebols in the Korean capital markets. With respect to the empirical results obtained from two hypothesis tests, the first hypothesis was to identify any financial determinants on the growth rate by applying both dynamic panel data and static panel data models. The debt ratios relevant to the book- and market-value showed their positive relationships with the DV of GROWTH1, along with other significant IDVs such as one-period lagged DV of GROWTH_1, SIZE1 and FOS with statistical significance. Second, by employing conditional quantile regression (CQR) analysis, the control variables, such as ROA, SMARKET, time dummy variable of F2010 and F2011, and the industry dummies of IND3 and IND10, provided evidence of their significant influences on DV of GROWTH1.

• Korean Journal of Social Welfare Studies
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• no.36
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• pp.253-280
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• 2008

Previous research indicates that depressive symptoms and alcohol consumption are highly correlated with each other. However, there is lack of consensus on the causal relationship between depressive symptoms and alcohol use. In order to address this limitation, this paper examines causal relationship between the two variables using non-recursive structural equation modeling, controlling sociodemographic and psycho-socio-behavioral variables. Data included 14,469 community dwelling individuals who participated in Korea Welfare Panel Study in 2006. Results showed that the effects of alcohol consumption on depressive symptoms was statistically significant, whereas the effects of depressive symptoms on alcohol consumption was not. Significant portions of the effects of psycho-socio-behavioral variables on depressive symptoms were indirect through their effects on alcohol consumption. Based on the results, implications for intervention and future research were discussed.

• Asia-Pacific Journal of Business
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• v.13 no.1
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• pp.277-288
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• 2022

Purpose - This study analyzed the determinants of local unemployment rate in Korea using panel data from 16 metropolitan cities and provinces from 2000 to 2018. Design/methodology/approach - We use a dynamic spatial panel model that considers characteristics of the regional unemployment rate such as the common factors effect, spatial dependence, and serial correlations. Findings - The local unemployment rate is affected by the past and present values of the national unemployment rate. And it is significantly affected by the past local unemployment rate and the past neighboring unemployment rate because spatial dependence and serial correlations are clearly present. In addition, when the industrial structure diversity and labor productivity were high, the regional unemployment rate decreased, and when the education level was high, the regional unemployment rate increased. Research implications or Originality - In order to reduce regional unemployment rate, it is necessary to plan and establish regional customized industrial structure policies under the stance of diversification rather than specializing the regional industrial structure and accompany improvement of the quality of education with the number of years of education. In addition, the redistribution of labor from low labor productivity sectors to high labor productivity sectors through technology development will help to reduce the local unemployment rate.

• The Journal of Society for e-Business Studies
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• v.25 no.4
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• pp.125-141
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• 2020

Recent Studies emphasize the effect of investors attention, recognition and sentiment on the trading behavior of retail investors and stock price variation. In this study, we use Naver Trend to measure investors'attention and investigate the relation between investor attention and price synchronicity, total risk and systematic risk of stocks. Using various research methodologies such as portfolio analysis, fixed effect regression and dynamic panel analysis, we find consistent results. First, stock price synchronicity is increased with lager average search volume, but with less search variability. Second, both average search volume and its variability are positively related to total risk and beta of stocks. These results can be interpreted that search volume sharply increases only when stock-related event occurs.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.10
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• pp.3666-3672
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• 2010

This study dealt with the controller design of the cooling system for controlling the inside temperature of the LCD panel console(the rest console') using as an outdoor billboard. The cooling performance of the LCD console that had been developed by the preceding research, was insufficient in the performance of the controller. In order to improve the performance of the system, in this study defined the structure and the design condition of the system first, after measured the parameters having influence on the dynamic characteristics, and developed the mathematical model for the analysis of the system. Finally planned a controlling scheme of the system and simulated the controller for the performance checking, compared the performance of this system controller with the preceding one. The purpose of this study is the presentation of the more improving method for the system control.