• 아태비즈니스연구
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• 제15권1호
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• pp.335-352
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• 2024

Purpose - Low fertility rate is a serious problem, and this study analyzes factors affecting total fertility rate using panel data from 16 metropolitan cities and provinces in Korea from 2000 to 2022. Design/methodology/approach - Estimating the SAR model considering the weak cross-sectional dependence that exists in variables related to the regional total fertility rate, and using the DKSE estimation method considering the strong cross-sectional dependence. Findings - Estimation results considering weak and strong cross-sectional dependence were similar, confirming the robustness of the results. Female labor force participation rate has a positive effect on total fertility rate, and employment rate has no effect. However, the interaction term is a negative (-) sign. Crude marriage rate has a positive effect on total fertility rate, and apartment price has a slightly positive effect. Environmental factor has no effect, and policy factor has a negative effect. Research implications or Originality - In order for an increase in the female labor force participation rate to lead to an increase in the total fertility rate, qualitative improvements in female employment must be made. Financial investment policies for childbirth must increase their effectiveness. The problem of low fertility rate requires not only population policy but also social, economic, cultural, environmental, and policy conditions to be considered.

• 대한안전경영과학회지
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• 제1권1호
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• pp.231-239
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• 1999

CAPM explains the rate of return for the risk asset by $\beta$, systematic risk. There are some assumption in CAPM. But CAPM can not explain the movement of stock price sufficiently due to limitation of the assumptions. Therefore many scholars study which variables with the exception of $\beta$ effect on the rate of return of risk asset for supplementing this limitation by using PER, size of firm etc.. But it will be natural that PER, size of firm etc. to be determinant factors of $\beta$ also effect on the abnormal rate of return, because PER, size of firm etc. used in their studies already effect on determination of $\beta$, . That is, the determinant factors of $\beta$ effect on determination of abnormal rate of return according as $\beta$, effects on abnormal rate of return. Therefore, this study tests empirically how the determinant factors of $\beta$, effect on determination of$\beta$, ,and how $\beta$ and the determinant factor of $\beta$ effect on the abnormal rate of return in CAPM.

• 오토저널
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• 제4권3호
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• pp.24-39
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• 1982

It has already been known that quenching effect is influenced greatly by stirring and changing coolant's temperature on quenching. But according to the past investigations its effect has not been taken into consideration quantitatively in the cooling process. The purpose of this study is that the influence of flow rate and temperature on the quenching effect of cooling water as quenching medium is quantitatively examined by using the open channel. The stream of water in this study is turbulent flow. The temperature of the specimen made of pure copper is measured by CA thermocouple in the vicinity of the surface and recorded by an automatic recorder during the quenching process in city water. The results obtained are as follows; 1. The quenching effect of cooling water generally increases with Reynolds Number(characteristic length; specimen diameter)as shown in the experimental formula; but at the realm of Reynolds Number from 1.2 * 10$^{4}$ to 9.2 * 10$^{4}$, the increasing rate of quenching effect shows little increase. 2. The increasing rate of quenching effect was increased under the flow rate of 221 cm/sec. On the other hand, it was decreased below this flow rate. 3. The quenching effect was influenced by the water temperature and the flow rate. But it was rather dependent upon the former than the latter. 4. Although the quenching effect appeared loosely in the water temperature of 50.deg. C, it was shown that the quenching effect increased in the low flow rate of 31 cm/sec. comparing with the still water. 5. It is desirable to design the quenching system to be over 1.2 * 10$^{4}$ in Reynolds Number or over, 3000$cm^{-1}$ / in V/v in order to increase the quenching effect of the system using open channel.annel.

• Nuclear Engineering and Technology
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• 제55권3호
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• pp.958-967
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• 2023

This work studies the defect features in a dilute FeMnNi alloy by an Object Kinetic Monte Carlo (OKMC) model based on the "grey-alloy" method. The dose rate effect is studied at 573 K in a wide range of dose rates from 10^-8 to 10^-4 displacement per atom (dpa)/s and demonstrates that the density of defect clusters rises while the average size of defect clusters decreases with increasing dose rate. However, the dose-rate effect decreases with increasing irradiation dose. The model considered two realistic mechanisms for producing <100>-type self-interstitial atom (SIA) loops and gave reasonable production ratios compared with experimental results. Our simulation shows that the proportion of <100>-type SIA loops could change obviously with the dose rate, influencing hardening prediction for various dose rates irradiation. We also investigated ways to compensate for the dose rate effect. The simulation results verified that about a 100 K temperature shift at a high dose rate of 1×10^-4 dpa/s could produce similar irradiation microstructures to a lower dose rate of 1×10^-7 dpa/s irradiation, including matrix defects and deduced solute migration events. The work brings new insight into the OKMC modeling and the dose rate effect of the Fe-based alloys.

• 한국병원경영학회지
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• 제27권1호
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• pp.43-57
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• 2022

Background: Avoidable mortality rate has been widely used as an indicator of the quality of health care and the degree of inequality in health levels. The purpose of this study was to identify the factors affecting the avoidable mortality rate in the region. Methods: The data was MDIS(Microdata Integrated Service) Causes of Death Statistics, and the analysis period was from 2010 to 2019. Panel analysis was performed to identify the influencing factors on the avoidable mortality rate. Findings: Result showed that the current smoking rate had a significant positive effects on the avoidable mortality rate of both men and women. And the smoking cessation trial rate, low salt diet rate, weight control trial rate, annual vaccination rate had a significant negative effect. In the social environment, the divorce rate had a significant positive effect. In the economy environment, financial independence and social welfare budget rate had a significant negative effect. In the physical environment, the factory area rate had a significant positive effect. Practical Implication: Practical implication in order to lower the local avoidable mortality rate, various social determinants of health as well as health care resources should be considered together.

• 한국항공우주학회지
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• 제36권3호
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• pp.264-270
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• 2008

하이브리드 로켓 고체 연료의 연소율(Burning Rate)을 묘사하는 후퇴율은 연료 유속, 산화제 유속과 더불어 연료길이의 함수로 나타내어지나 일반적으로 가장 영향이 큰 산화제 유속만의 함수로 모델링된다. 그러나 이는 연료가 갖고 있는 고유의 열화학적 특성에 대한 영향이 내포되어 있지 않아 다양한 연료에 대한 공통된 관계를 나타내기 어렵다. 본 연구에서는 고체연료의 열화학적 특성과 연소에 따른 공기역학적 특성이 고려된 물질전달수(B Number)를 도입하여 다양한 연료에 공통으로 사용될 수 있는 연소율 관계식을 제시하고, 물질전달수 내의 공기역학적 특성의 영향을 분석하였다. 물질전달수와 산화제 유속의 함수로 표현된 연소율 식은 고정된 실험 지수항과 상수항으로 PMMA, PP 및 PE의 연소율을 모두 묘사할 수 있었고, 연소율 관계식에서 B Number에 내포된 공기역학적 효과는 미미하였다.

• International Journal of Concrete Structures and Materials
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• 제10권3호
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• pp.307-323
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• 2016

The nonlinear behaviors of recycled aggregate concrete (RAC) frame structure are investigated by numerical simulation method with 3-D finite fiber elements. The dynamic characteristics and the seismic performance of the RAC frame structure are analyzed and validated with the shaking table test results. Specifically, the natural frequency and the typical responses (e.g., storey deformation, capacity curve, etc.) from Model 1 (exclusion of strain rate effect) and Model 2 (inclusion of strain rate effect) are analyzed and compared. It is revealed that Model 2 is more likely to provide a better match between the numerical simulation and the shaking table test as key attributes of seismic behaviors of the frame structure are captured by this model. For the purpose to examine how seismic behaviors of the RAC frame structure vary under different strain rates in a real seismic situation, a numerical simulation is performed by varying the strain rate. The storey displacement response and the base shear for the RAC frame structure under different strain rates are investigated and analyzed. It is implied that the structural behavior of the RAC frame structure is significantly influenced by the strain rate effect. On one hand, the storey displacements vary slightly in the trend of decreasing with the increasing strain rate. On the other hand, the base shear of the RAC frame structure under dynamic loading conditions increases with gradually increasing amplitude of the strain rate.

• 한국조경학회지
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• 제21권4호
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• pp.29-41
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• 1994

The purposes of this study are (a)to investigate the effect of follow-up on the increase of response rate;(b)to analyze the effect of follow-up on the statistics by predetermined response rates ; therefore, (c)to describe the importance of high response rate and to suggest methods in order to increase response rate in mail survey. Telephone directory of Seoul was utilized as a sampling frame, and modified Total Design Method(TDM) was applied to collect the data. The results are summarized as follows. 1. Final response rate was 76.5% by 2 follow-ups. 2. The first follow-up with telephone call had a significant effect on increase of response rate. As a result, follow-up by postcard in TDM could be omitted in this method. 3. The second follow-up by registered mail did not have a significant effect. Therefore, use of this procedure is depending upon such research situtations as importance of high response rate and cost available. 4. Follow-ups helped to make collected sample highly representative. 5. Most questionnaires were arrived on the first half of data collection period in each follow-up. 6. Most of questionnaires were collected for 10 weeks. Accumulated responses could be fitted by exponential and logistic curve, simultaneously. The fitted curve suggested that eventually limited number of questionnaires by arrived. So, if researchers want higher response rate, they have to conduct more follow-ups. 7. Statistics in the predetermined response rate were not changed significantly. But replications are needed to generalize this result.

• Nuclear Engineering and Technology
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• 제48권6호
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• pp.1376-1386
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• 2016

This study investigated the loading rate effect on the fracture resistance under cyclic loading conditions to understand clearly the fracture behavior of piping materials under seismic conditions. J-R fracture toughness tests were conducted under monotonic and cyclic loading conditions at various displacement rates at room temperature and the operating temperature of nuclear power plants (i.e., $316^{\circ}C$). SA508 Gr.1a low-alloy steel and SA312 TP316 stainless steel piping materials were used for the tests. The fracture resistance under a reversible cyclic load was considerably lower than that under monotonic load regardless of test temperature, material, and loading rate. Under both cyclic and monotonic loading conditions, the fracture behavior of SA312 TP316 stainless steel was independent of the loading rate at both room temperature and $316^{\circ}C$. For SA508 Gr.1a lowalloy steel, the loading rate effect on the fracture behavior was appreciable at $316^{\circ}C$ under cyclic and monotonic loading conditions. However, the loading rate effect diminished when the cyclic load ratio of the load (R) was -1. Thus, it was recognized that the fracture behavior of piping materials, including seismic loading characteristics, can be evaluated when tested under a cyclic load of R = -1 at a quasistatic loading rate.

• 무역학회지
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• 제44권1호
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• pp.17-30
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• 2019

This study is to investigate the effect of real exchange rate on bilateral trade balance between Korea and ASEAN 10 countries. Using quarterly data from 1991 to 2017 the paper analyzes whether or not the real depreciation of Korea's won could improve the trade balance in the short and long term. Based on Autoregressive Distributed Lag(ARDL) model, the empirical results show that trade balance, GDP, and real exchange rate are all cointegrated, representing the long-run relationship among variables. In the consideration of long-run relationship, the increases in ASEAN countries' GDP could have a negative impact and Korea's GDP positive impact on trade balance between Korea and ASEAN countries unexpectedly. For the main variable, the paper did not find the long-term effect of real exchange rate on the trade balance, for the short-term effect of the real exchange rate it was found that there exists the J-curve effect only in the case of Vietnam and Brunei. Therefore, these results imply that the intended policy concerning the exchange rate in the free-floating exchange rate system could be limited to improve the trade balance between Korea and ASEAN countries.