• International Area Studies Review
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• v.20 no.2
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• pp.63-83
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• 2016

This paper examines the determinants of efficiency in a KOSDAQ-listed manufacturing firm. We use Data Envelopment Analysis (DEA) to estimate the efficiency of the export manufacturing firm. We employ two inputs (number of employees, equity) and one output (sales) in the DEA. The determinants of export manufacturing firm efficiency are estimated using the panel Tobit model. An analysis of 369 export manufacturing firms from 2013 to 2015 indicates the following results: First, the R&D intensity, the wage and salary intensity, total asset, and equity ratio each had a negative impact on both the CCR and BCC efficiency scores. However, export intensity had a negative impact on CCR efficiency scores in a KOSDAQ-listed total export manufacturing firm. Second, the R&D intensity had a positive impact on both the CCR and BCC efficiency scores, but export intensity, the wage and salary intensity, and equity ratio each had a negative impact on the CCR and BCC efficiency scores in a KOSDAQ-listed large export manufacturing firm. Third, the R&D intensity, the wage and salary intensity, total asset, and equity ratio each had a negative impact on both the CCR and BCC efficiency scores; respectively, in a KOSDAQ-listed small and medium export manufacturing firm.

• Korean Journal of Remote Sensing
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• v.33 no.5_3
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• pp.821-834
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• 2017

The increase in the rate of industrialization due to urbanization has caused the Urban Heat Island phenomenon where the temperature of the city is higher than the surrounding area, and its intensity is increasing with climate change. Among the cities where heat island phenomenon occurs, Seoul city has different degree of urbanization, green area ratio, energy consumption, and population density in each administrative district, and as a result, the strength of heat island is also different. So It is necessary to analyze the difference of Urban Heat Island Intensity by administrative district and the cause. In this study, the UHI intensity of the administrative gu and the administrative dong were extracted from the Seoul metropolitan area and the differences among the administrative districts were examined. and linear regression analysis were conducted with The variables included in the three categories(weather condition, anthropogenic heat generation, and land use characteristics) to investigate the cause of the difference in heat UHI intensity in each administrative district. As a result of analysis, UHI Intensity was found to be different according to the characteristics of administrative gu, administrative dong, and surrounding environment. The difference in administrative dong was larger than gu unit, and the UHI Intensity of gu and the UHI Intensity distribution of dongs belonging to the gu were also different. Linear regression analysis showed that there was a difference in heat island development intensity according to the average wind speed, development degree, Soil Adjusted Vegetation Index (SAVI), Normalized Difference Built-up Index (NDBI) value. Among them, the SAVI and NDBI showed a difference in value up to the dong unit and The creation of a wind route environment for the mitigation of the heat island phenomenon is necessary for the administrative dong unit level. Therefore, it is considered that projects for mitigating heat island phenomenon such as land cover improvement plan, wind route improvement plan, and green wall surface plan for development area need to consider administrative dongs belonging to the gu rather than just considering the difference of administrative gu units. The results of this study are expected to provide the directions for urban thermal environment design and policy development in the future by deriving the necessity of analysis unit and the factors to be considered for the administrative city unit to mitigate the urban heat island phenomenon.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.4
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• pp.197-202
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• 2000

A simple numerical procedure is presented to determine the stress intensity factors for crack in a stiffened panel subjected to a uniaxial uniform stress normal to the crack. Two types of stiffened panels are analyzed by the finite element method for various values of crack lengths, stiffness ratios, and stiffener spacings. From the finite element solution, the stress intensity factors were determined by using hybrid extrapolation method. Results are presented in graphical forms for upper mentioned parameters.

• Economic and Environmental Geology
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• v.19 no.4
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• pp.297-304
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• 1986

Earthquake disaster is dependent upon both site intensity and strength of structures. The higher the strength, structures become more safe, which in turn increases the construction cost. Therefore, it is necessary to decide an optimum design intensity in which the safety is balanced with the cost. Such an optimum design intensity for major man-made structures in Korea is determined in the present study from a simulation model as follows. 1) Hypothetical earthquake time series are generated from the probability distribution to represent appropriately the seismicity of Korea. 2) The strength of structures constructed with a certain design intensity is assumed to exponentially decrease with the elapsed time. The construction cost is also expressed as a function of design intensity. 3) Comparing the seismic intensity generated from the earthquake time series with the strength of structures, the safety of structures is examined. Then the time until the structure is damaged by an earthquake is obtained within the designed life time. 4) The above simulation is iterated several hundred times and hence the mean life time of structures having a certain design intensity is obtained. 5) After all, the optimum design intensity to minimize the annual mean loss, the ratio of construction cost to mean life time, is estimated. The major conclusions obtained from the above simulation model are as follows. 1) Depending upon the designed life time ($T_p$), the optimum design intensities are appeared to be 0. 05-0. 10g for $T_p=50yr$ and 0. 08-0.13g for $T_p=100yr$. 2) According to the sensitivity analysis, the optimum design intensity increases with the rapid strength decrease of structure and decreases with the increase of initial construction cost.

• Journal of the Korean Society of Physical Medicine
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• v.10 no.1
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• pp.63-69
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• 2015

PURPOSE: Low-intensity exercise with transient restriction of blood flow to muscle could be an alternative rehabilitation method which avoids the problems associated with conventional high-intensity exercise. However, the mechanism of low-intensity exercise with transient restriction of blood flow is not clearly known. Thus, the purpose of this study was to investigate the mechanism of improvement of muscular function after low-intensity exercise with transient restriction of blood flow using H-reflex analysis. METHODS: Twenty one healthy young adults with no medical history of neurological or musculoskeletal disorder voluntarily participated in this study. The ${\alpha}$-motor neuron excitability of the triceps surae was assessed using the H-reflex. The amplitude of the M-wave and H-reflex were measured across three conditions: rest, after low-intensity exercise without restriction of blood flow and after low-intensity exercise with restriction of blood flow. The subjects performed low-intensity ankle plantar flexion exercise at their own pace for one minute without or with transient restriction of blood flow achieved by a sphygmomanometer cuff on popliteal fossa at a pressure of 120mm of mercury(120 mmHg). RESULTS: No significant changes of the excitability of the ${\alpha}$-motor neuron were obtained across three different conditions. CONCLUSION: This study found that low-intensity exercise with transient restriction of blood flow did not influence to ${\alpha}$-motor neuron excitability of the triceps surae. From the results, I could come to the conclusion that further study will be required.

• Korean Journal of Clinical Pharmacy
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• v.31 no.3
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• pp.198-204
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• 2021

Background: Cardiovascular (CV) disease is known as one of the major causes of death from disease worldwide. Statin therapy plays a pivotal role in atherosclerotic cardiovascular disease (ASCVD) lowering the LDL-cholesterol level effectively. The purpose of this study was to evaluate the association of the intensity of statin therapy in adult patients of Korea and the risk of ASCVD of the patient group. Methods: We used data from sample of patients from the Health Insurance Review and Assessment Service (HIRA-NPS-2018). We analyzed the patterns of prescribing statins including types of statin, statin intensity, and number of patients with ASCVD or risk of ASCVD. Results: 155,512 patients were included in the analysis, and 27,950 patients (18.0%) was over 75 years. High-intensity statin usage was increased in ASCVD patients compared with the low-intensity statin use. The OR (odds ratio) of high-intensity statin were increased in myocardial infarction patients compared with low-intensity statin use showing the highest OR; 12.40 (95% CI; 9.48-16.22). At patient groups of angina, ischemic heart disease and carotid disease, high-intensity statin prescription rate was increased compared with low-intensity statin. However, there was no statistical significance between both statin prescription rates in patients of peripheral arterial disease, abdominal aneurysm, diabetic mellitus and atherosclerosis. Conclusion: The statin prescription rate showed intensity increasing tendency according to the risk of ASCVD. More aggressive statin therapy might be beneficial for the ASCVD patients based on the recent guidelines of dyslipidemia.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.4
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• pp.336-345
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• 2012

In crack growth life, uncertainties are caused by variance of geometry, applied loads and material properties. Therefore, the reliability estimation for these uncertainties is required to keep the robustness of calculated life. The stress intensity factors are the most important variable in crack growth life calculation, but its equation is hard to know for complex geometry, therefore they are processed by the finite element analysis which takes long time. In this paper, the response surface is considered to increase efficiency of the reliability analysis for crack growth life of a turbine wheel. The approximation model of the stress intensity factors is obtained by the regression analysis for FEA data and the response surface of crack growth life is generated for selected factors. The reliability analysis is operated by the Monte Carlo Simulation for the response surface. The results indicate that the response surface could reduce computations that need for reliability analysis for the turbine wheel, which is hard to derive stress intensity factor equation, successfully.

• The KIPS Transactions:PartB
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• v.16B no.6
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• pp.471-478
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• 2009

The lung diseases classifying as one of the six incurable diseases in modern days are caused mostly by smoking and air pollution. Such causes the lung function damages, and results in malfunction of the exchange of carbon dioxide and oxygen in an alveolus, which the interest is augment with risk diseases of life prolongation. With this in the paper, we proposed a diagnosis method of lung diseases by applying parameters of voice analysis aiming at the getting the voice feature extraction. Firstly, we sampled the voice data from patients and normal persons in the same age and sex, and made two sample groups from them. Also, we conducted an analysis by applying the various parameters of voice analysis through the collected voice data. The relational significance between the patient and normal groups can be evaluated in terms of speech rates and intensity as a part of analized parameters. In conclusion, the patient group has shown slower speech rates and bigger intensity than the normal group. With this, we propose the method of voice feature extraction for lung diseases.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.2
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• pp.475-485
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• 1995

In this study, statistical analysis of fatigue data which had obtained from respective 24 fatigue crack, was examined for SiC whisker reinforced aluminium 6061 composite alloy (SiC$_{w}$/A16061) and aluminium 6061 alloy. SiC volume fraction in composite alloy is 25%. The analysis results stress intensity factor range and 0.1 mm fatigue crack initiation life for SiC$_{w}$/A16061 composite & A16061 matrix are the log-normal distribution. And regression analysis by linear model, exponential model and multiplicative model were performed to find out the relationship between fatigue crack growth rate(da/dN) and stress intensity for find out the relationship between fatigue crack growth rate(da/dN) and stress intensity factor range(.DELTA.K) in the SiC$_{w}$/A16061 composite and examine the applicability of Paris' equation to SiC$_{w}$A16061 composite. Also computer simulation was performed for fatigue life prediction of SiC$_{w}$/A16061 composite using the statistical results of this study.udy.

• Nuclear Engineering and Technology
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• v.49 no.4
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• pp.838-849
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• 2017

This paper proposes penalty factor equations that take into consideration the weld strength over-match given in the classified form similar to the revised equations presented in the Code Case N-779 via cyclic elastic-plastic finite element analysis. It was found that the $K_e$ analysis data reflecting elastic follow-up can be consolidated by normalizing the primary-plus-secondary stress intensity ranges excluding the nonlinear thermal stress intensity component, $S_n$ to over-match degree of yield strength, $M_F$. For the effect of over-match on $K_n{\times}K_{\nu}$, dispersion of the $K_n{\times}K_{\nu}$ analysis data can be sharply reduced by dividing total stress intensity range, excluding local thermal stresses, $S_{p-lt}$ by $M_F$. Finally, the proposed equations were applied to the weld between the safe end and the piping of a pressurizer surge nozzle in pressurized water reactors in order to calculate a cumulative usage factor. The cumulative usage factor was then compared with those derived by the previous $K_e$ factor equations. The result shows that application of the proposed equations can significantly reduce conservatism of fatigue assessment using the previous $K_e$ factor equations.