• Environmental and Resource Economics Review
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• v.28 no.2
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• pp.231-276
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• 2019

This paper analyzed the impact of the penetration of EV(electric vehicle) and FCEV(fuel cell electric vehicle) into the automobile industry, using a static CGE approach. There are contrasting view on the economic impact of EV/FCEV penetration: negative economic impact due to shrunken intermediate inputs versus positive impact because of input saving technical progress. Regarding environment, there is no clear consensus whether EV or FCEV will contribute to the reduction of $CO_2$ emissions in Korea. This study attempts to provide an answer to these questions. By giving shocks to the input coefficients of automobile industries and automobile using sectors, as well as to the final demands for energies. we integrated the Bass diffusion model into the CGE framework, The result suggests that the EV penetration has adverse impact on the $CO_2$ emission while the FCEV penetration has positive impact. On the other hand, both EV and FCEV have positive impacts on GDP. When considering automobile manufacturing sectors only, adverse impacts on $CO_2$ are demonstrated both for EV and FCEV. However, since the size of $CO_2$ increase is small, these results does not alter the overall effects.

• Journal of the Korean Wood Science and Technology
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• v.47 no.4
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• pp.519-532
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• 2019

The objectives of this study were to evaluate the effects of shelling ratio and resin content on the properties of bamboo oriented strand board (BOSB) from betung (Dendrocalamus asper) and to determine the correlation between the results of dynamic and static bending tests. Strands were steam-treated at $126^{\circ}C$ for 1 h under 0.14 MPa pressure and followed by washing with 1% NaOH solution. Three-layer BOSB with the core layer perpendicular to the surface was formed with shelling ratios (face:core ratio) of 30:70; 40:60; 50:50; 60:40 and binded with 7% and 8% of phenol formaldehyde (PF) resin with the addition of 1% of wax. The evaluation of physical and mechanical properties of BOSB was conducted in accordance with the JIS A 5908:2003 standard and the results were compared with CSA 0437.0 standard for commercial OSB (Grade O-1). Non-destructive testing was conducted using Metriguard Model 239A Stress Wave Timer which has a wave propagation time from 1 to $9,999{\mu}s$ and a resolution of $1{\mu}s$. BOSB with 8% resin content showed better physical and mechanical properties than those with 7% resin content. The increase of the face layer ratio improved the strength of BOSB in parallel direction to the grain. The results suggested that shelling ratio of 50:50 could be used as a simple way to reduce PF resin requirements from 8% to 7% and to meet the requirements of CSA 0437.0 standard. The results of non-destructive and destructive tests showed a strong correlation, suggesting that non-destructive test can be used to estimate the bending properties of BOSB.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.1
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• pp.391-400
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• 2019

In the case of fire, a structure loses its original stiffness due to the temperature rise, and the load bearing capacity decreases. The loss of structural strength increases with increasing fire time of the structure. To prevent the collapse of buildings, it is very important to understand whether or not the members are damaged. On the other hand, there is insufficient data to be a guideline for diagnosing and evaluating the residual strength of the members in Korea. Therefore, this study examined the resistance performance by Finite-Element-Analysis of composite beams, which are composite structures among structural members. Composite beam modeling was carried out based on the model used in the Electrical Penetration Room (EPR) in cooperation with KEPCO. The heat transfer analysis and structural analysis of the critical phase were performed using ANSYS, a finite element analysis program. ANSYS was used to perform heat transfer analysis and structural analysis at the static analysis. To analyze the residual performance, the temperature distribution of the composite beam and the maximum displacement result of the heat-affected structure analysis were derived and the experimental data and the structural analysis result data were compared and analyzed.

• The Journal of Korean Institute of Information Technology
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• v.16 no.11
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• pp.51-59
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• 2018

The Multi-Mission Unmanned Surface Vehicle(MMUSV), which is manufactured using glass Fiber Reinforced Plastic(FRP) material, is designed to perform a surveillance and reconnaissance on the sea. Various navigation sensors, such as RADAR, RIDAR, camera, are mounted on a mast to perform an autonomous navigation. And a dummy gun is mounted on the deck of the MMUSV for a target tracking and disposal. It is necessary to analyze a strength for structures mounted on the deck because the MMUSV performs missions under a severe sea state. In this paper, a strength analysis of the mast structure is performed on static loads and lateral external loads to verify an adequacy of the designed mast through a series of simulations. Based on the results of captive model tests, a strength analysis for a heave motion of the mast structure is conducted using a simulation tool. Also a simulation and fatigue test for a mounting part between the MMUSV and the dummy gun are performed using a specimen. The simulation and test results are represented that a structure of the mast and mounting part of the dummy gun are appropriately designed.he impact amount are performed through simulation and experiments.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.32 no.2
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• pp.125-132
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• 2019

This paper presents a seismic reliability analysis method for an offshore wind turbine with a twisted tripod support structure under earthquake loading. A three dimensional dynamic finite element model is proposed to consider the nonlinearity of the ground-pile interactions and the geometrical characteristics of the twisted tripod support structure where out-of-plane displacement occurs even under in-plane lateral loadings. For the evaluation of seismic reliability, the failure probability was calculated for the maximum horizontal displacement of the pile head, which is calculated from time history analysis using artificial earthquakes for the design return periods. The application of the subset simulation method using the Markov Chain Monte Carlo(MCMC) sampling is proposed for efficient reliability analysis considering the limit state equation evaluation by the nonlinear time history analysis. The proposed method can be applied to the reliability evaluation and design criteria development of the offshore wind turbine with twisted tripod support structure in which two dimensional models and static analysis can not produce accurate results.

• Smart Structures and Systems
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• v.24 no.6
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• pp.769-781
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• 2019

Dynamic displacement response of civil structures is an important index for in-construction and in-service structural condition assessment. However, accurately measuring the displacement of large-scale civil structures such as high-rise buildings still remains as a challenging task. In order to cope with this problem, a vision-based system with the use of industrial digital camera and image processing has been developed for long-distance, remote, and real-time monitoring of dynamic displacement of supertall structures. Instead of acquiring image signals, the proposed system traces only the coordinates of the target points, therefore enabling real-time monitoring and display of displacement responses in a relatively high sampling rate. This study addresses the in-situ experimental verification of the developed vision-based system on the Canton Tower of 600 m high. To facilitate the verification, a GPS system is used to calibrate/verify the structural displacement responses measured by the vision-based system. Meanwhile, an accelerometer deployed in the vicinity of the target point also provides frequency-domain information for comparison. Special attention has been given on understanding the influence of the surrounding light on the monitoring results. For this purpose, the experimental tests are conducted in daytime and nighttime through placing the vision-based system outside the tower (in a brilliant environment) and inside the tower (in a dark environment), respectively. The results indicate that the displacement response time histories monitored by the vision-based system not only match well with those acquired by the GPS receiver, but also have higher fidelity and are less noise-corrupted. In addition, the low-order modal frequencies of the building identified with use of the data obtained from the vision-based system are all in good agreement with those obtained from the accelerometer, the GPS receiver and an elaborate finite element model. Especially, the vision-based system placed at the bottom of the enclosed elevator shaft offers better monitoring data compared with the system placed outside the tower. Based on a wavelet filtering technique, the displacement response time histories obtained by the vision-based system are easily decomposed into two parts: a quasi-static ingredient primarily resulting from temperature variation and a dynamic component mainly caused by fluctuating wind load.

• The Journal of the Korea Contents Association
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• v.21 no.6
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• pp.248-260
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• 2021

This study assumes that the smooth school life of adolescents from multicultural families is recognized as an important part of multicultural support policies and practices as a basis for realizing an integrated society, and system elements that are meaningful for their flexibility to adapt to school (individuals, families, schools) By empirically analyzing the effect of, we tried to bring out highly effective implications for the composition of a multidimensional practice system. Therefore, this study is a causal model in which self-identity (individual factor) and parental parenting attitude (family factor), which are important variables for each system level, are set as independent variables, and school support (school factor) consisting of teacher support and companion support is set as control variables. After collecting data through a questionnaire survey by interviews with 162 middle and high school students in Gyeonggi and Gangwon regions, the effect was analyzed through multiple regression analysis. As a result of the analysis, it was confirmed that school support has a very important static moderating effect in the positive (+) effect of adolescents' self-identity and parenting attitude on school adaptability. It was confirmed that the modulating effect is relatively more important.

• The Korean Journal of Pain
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• v.34 no.3
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• pp.250-261
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• 2021

Background: Complex regional pain syndrome type I (CRPS-I) consists of disorders caused by spontaneous pain or induced by some stimulus. The objective was to verify the effects of photobiomodulation (PBM) using 830 nm wavelength light at the affected paw and involved spinal cord segments during the warm or acute phase. Methods: Fifty-six mice were randomized into seven groups. Group (G) 1 was the placebo group; G2 and G3 were treated with PBM on the paw in the warm and acute phase, respectively; G4 and G5 treated with PBM on involved spinal cord segments in the warm and acute phase, respectively; G6 and G7 treated with PBM on paw and involved spinal cord segments in the warm and acute phase, respectively. Edema degree, thermal and mechanical hyperalgesia, skin temperature, and functional quality of gait (Sciatic Static Index [SSI] and Sciatic Functional Index [SFI]) were evaluated. Results: Edema was lower in G3 and G7, and these were the only groups to return to baseline values at the end of treatment. For thermal hyperalgesia only G3 and G5 returned to baseline values. Regarding mechanical hyperalgesia, the groups did not show significant differences. Thermography showed increased temperature in all groups on the seventh day. In SSI and SFI assessment, G3 and G7 showed lower values when compared to G1, respectively. Conclusions: PBM irradiation in the acute phase and in the affected paw showed better results in reducing edema, thermal and mechanical hyperalgesia, and in improving gait quality, demonstrating efficacy in treatment of CRPS-I symptoms.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.248-258
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• 2021

The study analyzed the financial determinants of corporate R&D intensity that require more attention from academics and practitioners in the Korean capital market. Domestic small and medium enterprises (SMEs) may face with developing substitutes by making more R&D investments in scale and scope, given the unprecedented economic conditions such as the limitation of importing core components and materials from other nation(s). KOSDAQ-listed SMEs were selected as sample data, whose R&D expenditures may be less than those of large firms during the post-global financial turmoil period (2010~2018). Static panel data model was applied, along with Tobit and stepwise regression models, for examining the validity of results. Logit, probit, and complementary log-log regressions were also employed for a relative analysis. R&D expenditures in the prior year, the interaction effect between the previous R&D intensity and high-tech sector, firm size, and growth rate were significant to determine R&D intensity. Moreover, a majority of explanatory variables were found to change between the years 2011 and 2018, while time-lagged effects between the R&D intensity and growth rate exist. Results of the study are expected to be used for future research to detect optimal levels of R&D expenditures for the value maximization of SMEs.

• Journal of Industrial Convergence
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• v.18 no.6
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• pp.155-163
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• 2020

The purpose of this study was to verify the effect of job stress of caregivers on service quality for improve the quality of elderly long-term care services and the mediating effect of organizational commitment in the process. To this end, 30 long-term care facilities were randomly sampled out of 1,705 long-term care facilities in Gyeonggi-do, and as a result of a questionnaire survey of 500 caregiver for one month in May 2020, 443 samples were collected, and a total of 415 samples were finally analyzed. As for the analysis method, SPSS WIN 21.0 was used to verify the mediation model using frequency analysis, descriptive analysis, correlation analysis, and regression analysis. As a result of the study, first, job stress had a negative effect on service quality and organizational commitment. Second, organizational commitment has a static effect on service quality. Third, organizational commitment was verified as a perfect mediating in the relationship between job stress and service quality. This suggested the importance of the effect of organizational commitment in the process between job stress and service quality of caregivers and sought a policy ways to to improve the service quality of caregivers.