• Journal of the Korean Regional Science Association
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• v.35 no.2
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• pp.33-47
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• 2019

The purpose of this study is to examine the effect of urban decline on Subjective Well-being(SWB). According to the scale of the city, the municipal districts of Korea are classified into metropolitan cities, middle cities, and small cities. The SWB in the growth area, the maintenance area, and the declining area according to the degree of relative decline of each city group was examined. In addition, in order to consider the complex nature of urban decline, SWB was divided into overall life satisfaction, household income satisfaction, and housing environment satisfaction. Panel models were also used to identify the dynamic relationship between the progress of urban decay and the change in SWB. The empirical analysis of this study examined the effect of decline on the SWB for the local residents. As a result, it was confirmed that the effect of urban decline on the SWB of the residents varies according to the size of the city where the individual resides, according th the SWB by the division. In the case of metropolitan inhabitants, the decline of the housing environment of the residents due to deterioration of the physical environment was confirmed as a result of the decline of the city, but the overall life satisfaction was increased due to the decrease of the social costs such as congestion in an overcrowded area. On the contrary, in the case of the residents of the small cities, it is confirmed that the decline of the city reduces the overall life satisfaction, household income satisfaction, and housing environment satisfaction.

• Journal of Korean Society of Steel Construction
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• v.19 no.6
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• pp.751-760
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• 2007

The purpose of this study is to evaluate the seismic performance of the frame which is assumed to be used with Welded Unreinforced Flange-Bolted web (WUF-B) connections and detailed in compliance with FEMA 350 recommended seismic design criteria. In FEMA 350, these types of connections are only valid for Ordinary Moment-Resisting Steel Frames (OMRSFs). For this purpose, based on test results, we proposed an analytical model for the Post-Northridge WUF-B connections with different panel zone strength ratios. Using the connection model, SAC Phase II three and nine-story frames were modeled and analyzed. From a nonlinear static pushover analysis, ductility, maximum strength, and the maximum interstory drift ratio were investigated for buildings with Post-Northridge details. Moreover, the maximum interstory drift ratio of each performance level (IO and CP) was also investigated through Incremental Dynamic Analysis (IDA). Analytical results were compared with those of buildings with either Pre-Northridge connection or ductile connections with no fracture. The analytical results showed that buildings with Post-Northridge WUF-B connections provide superior strength and interstory drift ratio capacity than buildings with Pre-Northridge WUF-B connections.

• The Korean Journal of Financial Management
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• v.24 no.1
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• pp.109-147
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• 2007

According to the perspective of capital structure theory, we analyzed the dynamism of the capital structure determinants by using panel data of 244 KOSDAQ firms based on two-step GMM system methodology suggested by Blundell Bond(1998). This dynamic methodology had not been used to analyse capital structure determinants in Korea. In the dynamic model of capital structure, profit had negative effect on the book leverage and market leverage, which meant supporting pecking order theory. Growth opportunity (MBR) affected negatively to the market leverage. For the determinants of leverage, earnings volatility had significantly positive effect on KOSDAQ 50 firms. KOSDAQ and KOSDAQ 50 firms had the target leverage. The adjustment speed in KOSDAQ firms was 0.4958 on the book leverage, it was faster than in KOSDAQ 50 firm's 0.2863 on the book leverage and the adjustment speeds for the market leverage were 0.7651 for KOSDAQ firms and 0.5643 for KOSDAQ 50 firms. There was difference in adjustment cost between KOSDAQ firms and KOSDAQ 50 firms.

• The Journal of the Korea Contents Association
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• v.17 no.6
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• pp.504-513
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• 2017

This study investigated one of the controversial issues on debate or even controversial between policy makers at the government and corporate levels: To examine any financial determinants on the cash holdings of the firms in the advanced and emerging capital markets. Futhermore, it focused on the large representative firms headquartered in the U.S. and the Republic of Korea, taking into account scarcity of the previous literature concentrated on the comparative studies on this particular subject. Several legitimate, but robust econometric estimations such as static and dynamic panel data models and Tobit regression, were applied to investigate possible financial factors ono the cash liquidity. Given the continued debates or arguments on the excess cash reserves between interest partied at the government and corporate levels in the advanced and/or emerging capital markets, and more accelerated capital transfers among associated nations by engaging in the arrangements of the FTAs, the results of the study may provide a vision to search for the optimal level of corporate cash holdings for firms in the two nations.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.2
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• pp.127-134
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• 2020

High supersonic aircraft are exposed to high temperature environments by aerodynamic heating during supersonic flight. Thermal protection system structures such as double-panel structures are used on the skin of the fuselage and wings to prevent the transfer of high heat into the interior of an aircraft. The thin-walled double-panel skin can be exposed to acoustic loads by supersonic aircraft's high power engine noise and jet flow noise, which can cause sonic fatigue damage. Therefore, it is necessary to examine the behavior of supersonic aircraft skin structure under thermal-acoustic load and to predict fatigue life. In this paper, we designed and fabricated thermal-acoustic test equipment to simulate thermal-acoustic load. Thermal-acoustic testing of the titanium specimen under thermal-acoustic load was performed. The analytical model was verified by comparing the thermal-acoustic test results with the finite element analysis results.

• Journal of Digital Convergence
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• v.12 no.7
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• pp.65-76
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• 2014

This paper analyzes whether local public expenditures have converged during the 1985-2011 periods in Korea, using the sixteen metropolitan and provincial governments data. We analyze the convergence of per capita real local public expenditures in terms of both static view and dynamic view of convergence. Furthermore, we derive the estimating equation for per capita real local government expenditure growth function from theoretical model based on Skidmore et al.(2004)[23]. The main results from empirical analyses are such that an increase in aged people helped local government expenditures increase. Also, we found that the convergence speed of economic expenditure is greater than that of social welfare expenditure. Similarly the convergence speed of public capital expenditure is greater than that of public consumption expenditure. In the future we had better examine the convergence of local public goods taking into account their congestion rates.

• Korean Journal of Social Welfare
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• v.65 no.3
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• pp.183-206
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• 2013

Using Korean Labor and Income Panel Study (wave 1~11) database, this study analyzed the poverty duration of the poor as a whole and by households' characteristics. For this purpose, I first estimated poverty exit rates and reentry rates applying discrete-time hazard model to the sample, and then calculated poverty duration combining these two probability rates. The results show that about a half of poor households are transitory (short-term) poor with 1~2 years of poverty duration. A quarter is chronic (long-term) poor lasting for 5 or more years of poverty duration. The remained quarter can be categorized as the recurrent or mid-term poor. The socioeconomic characteristics of households greatly affect poverty duration. Long-term poverty is prevalent among female-head households, elderly households, single households, or households headed by a person with a lower level of education. If households' heads do not work, or work as temporary or daily-employed workers, the poverty duration tends to be longer. The findings suggest that the poor consist of various social classes with different characteristics. Efficient anti-poverty policy should be based on thoroughly identifying the specific characteristics and needs of each class.

• Smart Structures and Systems
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• v.13 no.4
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• pp.615-636
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• 2014

Aluminium Foam Sandwich (AFS) panels are becoming always more attractive in transportation applications thanks to the excellent combination of mechanical properties, high strength and stiffness, with functional ones, thermo-acoustic isolation and vibration damping. These properties strongly depend on the density of the foam, the morphology of the pores, the type (open or closed cells) and the size of the gas bubbles enclosed in the solid material. In this paper, the vibrational performances of two classes of sandwich panels with an Alulight(R) foam core are studied. Experimental tests, in terms of frequency response function and modal analysis, are performed in order to investigate the effect of different percentage of porosity in the foam, as well as the effect of the random distribution of the gas bubbles. Experimental results are used as a reference for developing numerical models using finite element approach. Firstly, a sensitivity analysis is performed in order to obtain a limit-but-bounded dynamic response, modelling the foam core as a homogeneous one. The experimental-numerical correlation is evaluated in terms of natural frequencies and mode shapes. Afterwards, an update of the previous numerical model is presented, in which the core is not longer modelled as homogeneous. Mass and stiffness are randomly distributed in the core volume, exploring the space of the eigenvectors.

• Earthquakes and Structures
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• v.14 no.3
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• pp.249-259
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• 2018

This paper aims to assess the seismic risk of a plane moment-resisting frames (MRFs) consisting of concrete-filled double skin steel tube (CFDST) columns and I-section steel beams. Firstly, three typical limit performance levels of CFDST structures are determined in accordance with the cyclic tests of seven CFDST joint specimens with 1/2-scaled and the limits stipulated in FEMA 356. Then, finite element (FE) models of the test specimens are built by considering with material degradation, nonlinear behavior of beam-column connections and panel zones. The mechanical behavior of the concrete material are modeled in compression stressed condition in trip-direction based on unified strength theory, and such numerical model were verified by tests. Besides, numerical models on 3, 6 and 9-story CFDST frames are established. Furthermore, the seismic responses of these models to earthquake excitations are investigated using nonlinear time-history analyses (NTHA), and the limits capacities are determined from incremental dynamic analyses (IDA). In addition, fragility curves are developed for these models associated with 10%/50yr and 2%/50yr events as defined in SAC project for the region on Los Angeles in the Unite State. Lastly, the annual probabilities of each limits and the collapse probabilities in 50 years for these models are calculated and compared. Such results provide risk information for the CFDST-MRFs based on the probabilistic risk assessment method.

• The Journal of Economics, Marketing and Management
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• v.7 no.1
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• pp.1-14
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• 2019

Purpose - Currently, the economic globalization has become a common channel for China's enterprise to perform the international economic activities. Due to this background, this paper tries to analyze the influence of internationalization level on operation performance of enterprises. Research design, data, and Methodology - This paper aims at 296 companies going listed in Shanghai Stock Exchange and Shenzhen Stock Exchange. The data about the listed companies during the 12 years from 2005 to 2016 have been collected. Relevant theories, including the theory of comparative advantage, monopolistic advantage and product life cycle in developed countries as well as the small scale technology and state on localized technological capacities in developing countries, have been summarized to provide theoretical basis for the influence of international operation on operation performance of the enterprises. Moreover, the current status of international operation of China's enterprises, including the dynamic cause of the internationalization of China's enterprises, its competitive advantage and disadvantage as well as the interest and potential risk of the internationalization, have been also analyzed. Results - Via adopting the panel data to conduct an empirical analysis, It can be found that the relationship between international operation level and operation performance of China's enterprises can be expressed as the S-curve of declining, rising and declining again. Conclusions - This paper has taken the lead in using Ohlson corporate value model to fill the gap in the relevant researches in China. It can also provide guidance for the international operation of China's enterprises. Meanwhile, the two systems for international operation and performance evaluation index have been put forward. The performance of international operation can be classified as financial performance or corporate value so that the operation effect of those China's enterprises going abroad can be better evaluated.