• The Journal of Asian Finance, Economics and Business
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• v.7 no.11
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• pp.607-617
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• 2020

This study investigates the causal relationship between public and private external debt and economic growth in developing countries. Our model includes 18 selected Asian developing and transition economies from 1995 thru 2019. We employ the dynamic heterogeneous panel data methods, pooled mean group (PMG), robust cross-sectional augmented autoregressive distributed lag (CS-ARDL), and pairwise panel causality test. The results of PMG and CS-ARDL show the existence of causality between external debt and economic growth both in the short-run and long-run. The pairwise Granger causality test found the bidirectional causal relationship runs from total external debt, public external debt, and private external debt to economic growth and economic growth to external debt. The results showed first the existence of causality in the short-run and long-run between external debt and economic growth and the second, bi-directional causality that runs from external debt to economic growth and economic growth to external debt. Both the dynamic models and robust estimator found the same inferences about the impact of main variables on economic growth in Asian developing and transition economies. The findings of this study suggest to assure debt management, investment in productive sectors, increase domestic savings, decrease external dependency, and focus on international trade.

• Journal of Family Resource Management and Policy Review
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• v.18 no.2
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• pp.163-182
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• 2014

This study examined the effects of informal grandparent-provided child care and support on married women's additional birth plans. This study applied panel data analysis to three waves of the Korean Longitudinal Survey of Women and Family (KLoWF) and obtained two major findings, as follows. First, having a mother-in-law and co-residing with parents-in-law had a positive influence on married working women's additional birth plans. Child care provision from the parents of a married working woman also positively influenced her additional birth plans. Second, the analysis showed that housework assistance from a woman's mother-in-law or mother had no effect on her birth plans in both models investigated: the additional birth plan model for all women, both employed and unemployed, and the additional birth plan model for only working women. In conclusion, the findings of this study demonstrated that child care availability, with grandparents as the trusted providers, is a more important factor in married women's additional birth plans than housework assistance from their mothers-in-law and mothers.

• Journal of Korea Multimedia Society
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• v.24 no.2
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• pp.222-232
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• 2021

The power output of solar panels highly depends on environmental situations like weather and air pollution. Due to bad weather or air pollution, it is difficult for solar panels to operate at their full potential. Knowing the power output of solar panels in advance helps set up the solar panels correctly and work their possible potential. This paper presents an approach to predict the power output of solar panels based on weather and air pollution features using machine learning methods. We create machine learning models with three kinds set of features, such as weather, air pollution, and weather and air pollution. Our datasets are collected from the area of Seoul, South Korea, between 2017 and 2019. The experimental results show that the weather and air pollution features can be efficient factors to predict the power output of solar panels.

• Steel and Composite Structures
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• v.37 no.6
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• pp.633-647
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• 2020

This paper aims to study the seismic performance of external diaphragm connection between SST (square steel tube) column and H-shaped beam through experimental and analytical study involving finite element (FE) method and theoretical analysis. In the experimental study, three external diaphragm connection specimens with weak panel zone were tested under axial pressure on the top of the column and antisymmetric cyclic loads at the beam end to investigate the seismic performance of the panel zone. The hysteretic behavior, failure mode, stiffness and ductility of the specimens were discussed. Key point to be explored was the influence of the thickness of the steel tube flange on the shear capacity of the specimens. In the analytical study, three simplified FE models were developed to simulate the seismic behavior of the specimens for further analysis on the influence of steel tube flange. Finally, four existing calculation formulas for the shear capacity of the external diaphragm connection were evaluated through comparisons with the results of experiments and FE analysis, and application suggestions were put forward.

• Advances in aircraft and spacecraft science
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• v.9 no.5
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• pp.377-400
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• 2022

The aim of this work is a numerical comparison (FEM) between lattice pyramidal-core panel and honeycomb core panel for different core thicknesses. By evaluating the mid-span deflection, the shear rigidity and the shear modulus for both core types and different core thicknesses, it is possible to define which core type has got the best mechanical behaviour for each thickness and the evolution of that behaviour as far as the thickness increases. Since a specific base geometry has been used for the lattice pyramidal core, the comparison gives us the opportunity to investigate the unit cell strut angle giving the higher mechanical properties. The presented work considers a detailed FEM modelling of a standard 3-point bending test (ASTM C393/C393M Standard Practice). Detailed FEM modelling addresses to detailed discretization of cores by means of beam elements for lattice core and shell elements for honeycomb core. Facings, instead, have been modelled by using shell elements for both sandwich panels. On lattice core structure, elements of core and facings are directly connected, to better simulate the additive manufacturing process. Otherwise, an MPC-based constraint between facings and core has been used for honeycomb core structure. Both sandwich panels are entirely built of Aluminium alloy. Prior to compare the two models, the FEM sandwich panel model with lattice pyramidal core needs to be validated with 3-point bending test experimental results, in order to ensure a good reliability of the FEM approach and of the comparison. Furthermore, the analytical validation has been performed according to Allen's theory. The FEM analysis is linear static with an increasing midspan load ranging from 50N up to 500N.

• Asian Journal of Business Environment
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• v.14 no.2
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• pp.11-18
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• 2024

Purpose: The purpose of this study is to empirically evaluate the unintended welfare losses induced by paid sick leave, examine the severity of the unintended moral hazard loss caused by paid sick leave, and evaluate how much moral hazard cost society can accept to obtain paid sick leave benefits. Research Design, Data and Methodology: We examine the Medical Expenditure Panel Survey data collected in 2013 and 2014 by employing a panel probit analysis to control for individual heterogeneity. Results: The estimation result shows that the probability of absence due to paid sick leave increases from 4.91% to 7.84%. Among them, excluding the probability of increasing absence from 1.29% to 2.69% due to the actual disease, the probability of absence due to the moral hazard was estimated to be 2.41% to 6.49% in the proposed models. Based on the result, if we evaluate the increase in absence caused by moral hazard as a social cost, the estimated cost is approximately $174 to $297 per worker per year. Conclusion: Considering these expected costs, our society can obtain the access benefit from paid sick leave if we are willing to accept the moral hazard cost.

• International Journal of Aeronautical and Space Sciences
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• v.16 no.2
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• pp.206-222
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• 2015

This work uses different finite element approaches to the free vibration analysis of reinforced shell structures, and a simplified model of a typical launcher with two boosters is used as an example. The results obtained using a refined one-dimensional (1D) beam model are compared to those obtained with commercial finite element software. The 1D models that are used in the present work are based on the Carrera Unified Formulation (CUF), which assumes a variable kinematic displacement field over the cross-sections of the beam. Two different sets of polynomials that correspond to Taylor (TE) or Lagrange (LE) expansions were used. The analyses focused on three reinforced structures: a stiffened panel, a reinforced cylinder and the complete structure of the launcher. The frequencies and natural modes obtained using one-dimensional models are compared to those obtained from classical finite element analysis. The classical FE models were built using a beam-shell or solid elements, and the results indicate that the refined beam models can in fact be used to investigate the behavior of very complex reinforced structures. These models can predict the shell-like modes that are typical of thin-walled structures that cannot be detected using classical beam models. The refined 1D models used in the present work provide results that are as accurate as those from solid FE models, but the 1D models have a much lower computational cost.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1994.10a
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• pp.38-45
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• 1994

P-version finite element model for the computation of stress intensity factors in two dimensional cracked panels by J-integral method is presented. The proposed model is based on high order theory and hierarchical shape function. The displacements fields are defined by integrals of Legendre polynomials which can be classified into three part such as basic mode, side mode, integral mode. The stress intensity factors are computed by J-integral method. The example models for validating the proposed p-version model are centrally cracked panel, single and double edged crack in a rectangular panel under pure Mode I. And the analysis results are compared with those by the h-version of FEM and empirical solutions in literatures. Very good agreement with the existing solution are shown.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.152-157
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• 2001

UTC(Unglazed Transpired Collector) system has recently emerged as a new solar air heating technology. It is relatively inexpensive because it has not a glazed material. And it demonstrates efficient particularly for the applications in which larger wall area facilities with a high outdoor air requirement. Mathematical algorithm for UTC thermal modeling has been understood for further improvement of the system. EES and TRNSYS model of actual solar wall panel could be developed for computer simulations under other conditions. Computer models could be validated with the measured data from fixed outdoor test cell in KIER(Korea Institute of Energy Research). Major design parameters could be identified such as panel configuration and absorptivity and emissivity values for UTC design.

• International Journal of Ocean System Engineering
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• v.3 no.1
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• pp.1-9
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• 2013

A design procedure for a ship with minimum resistance had been developed using a numerical optimization method called SQP (Sequential Quadratic Programming) combined with computational fluid dynamics (CFD) technique. The frictional resistance coefficient was estimated by the ITTC 1957 model-ship correlation line formula and the wave-making resistance coefficient was evaluated by the potential-flow panel method with the nonlinear free surface boundary conditions. The geometry of the hull surface was represented and modified by B-spline surface modeling technique during the optimization process. The Series 60 ($C_B$=0.60) hull was selected as a parent hull to obtain an optimized hull that produces minimum resistance. The models of the parent and optimized hull forms were tested at calm water condition in order to demonstrate the validity of the proposed methodolgy.