• Title/Summary/Keyword: impact coefficient

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Determinants of Marriage Intention for Korean Youth using Youth Panel Data (청년패널조사데이터를 활용한 결혼의도의 결정요인)

  • Myungkeun Song;Won Seok Lee;Joonho Moon
    • Asia-Pacific Journal of Business
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    • v.15 no.1
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    • pp.87-98
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    • 2024
  • Purpose - The purpose of this research is to explore the determinants of marriage intention for Korean youth. Because Korean society is under the population decline, inspecting influential attributes become worthy. Design/methodology/approach - This study employed Korean Youth panel data. The determinants of marriage intention include subjective health, leisure time, Schwabe index, culture recreation ratio, and Engel coefficient. This study performed binary logistic regression to test the hypotheses. Findings - The results indicate that subjective health and leisure time positively impact on the likelihood of marriage intention. However, culture recreation ratio and Engel coefficient negatively affect the likelihood of marriage intention. Schwabe index exerts no significant effect on marriage intention. Research implications or Originality - The results could become useful information to build policy to solve the population decline problem

The impact of meteorological parameters on the biological productivity of mycorrhizal mushrooms in Eastern Siberia

  • Muzyka, Sergey Mikhailovich;Bondarenko, Olga Valentynovna;Makarova, Elena Aleksandrovna
    • Journal of Species Research
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    • v.4 no.2
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    • pp.169-172
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    • 2015
  • The correlation coefficient (r) between the meteorological parameters and the gross biological productivity of the most common mycorrhizal mushrooms was determined. The results can be both of theoretical and practical importance.

Automobile Collision Reconstruction Using Post-Impact Velocities and Crush Profile (충돌 후 속도와 충돌 변형으로부터 자동차 충돌 재구성)

  • 한인환
    • Journal of Korean Society of Transportation
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    • v.18 no.4
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    • pp.107-115
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    • 2000
  • We suggest a method which solves the planar, two vehicle collision reconstruction problem. The method based on the Principle of impulse and momentum determines the pre-impact velocity components from Post-impact velocity components, vehicle Physical data and collision geometry. A novel feature is that although the impact coefficients such as the restitution coefficient and the impulse ratio are unknown, the method can estimate automatically the coefficients and calculate the pre-impact velocity components. This reverse calculation is important for vehicle accident reconstruction, since the pre-impact velocities are unknown and Post-impact Phase is the starting Point in a usual collision analysis. However. an inverse solution is not always Possible with the analytical rigid-body impact model. Mathematically, one does not exist under the common velocity condition. On the other hand, our method has a capability of reverse calculation under the condition if the absorbed energy during the collision process can be estimated using the crush profile. To validate the developed collision reconstruction a1gorithm, we use car-to-car collision test results. The analysis and experimental results agree well in the impact coefficients and the Pre-impact velocity components.

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Comparison Analysis of Vegetation Index and Degree of Green Naturality (식생지수와 녹지자연도의 비교평가)

  • Han, Eui-Jung;Kim, Myung-Jin;Hong, Jun-Suk;Seo, Chang-Wan
    • Journal of Environmental Impact Assessment
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    • v.6 no.2
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    • pp.181-188
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    • 1997
  • Vegetation is an important factor in EIA(Environmental Impact Assessment) and it is assessed according to DGN(Degree of Green Naturality) in EIS(Environmental Impact Statement) preparation. But DGN has room for improvement of assessing vegetation Status. This study introduced NDVI(Normalized Difference Vegetation Index) for improving status assessment method that subjects to DGN. For the application of NDVI, Landsat TM data of Chunchon on May 2, 1989 and June 1, 1994, and data of Ulsan on November 5, 1984, November 2, 1992 and May 9, 1994 were used. It compared NDVI with DGN according to season and location. The correlation coefficient value for the spring image (1994, 0.7, p=0.01) was proved to be higher than that of autumn (1984, 0.5, p=0.01).

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Performance and modeling of high-performance steel fiber reinforced concrete under impact loads

  • Perumal, Ramadoss
    • Computers and Concrete
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    • v.13 no.2
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    • pp.255-270
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    • 2014
  • Impact performance of high-performance concrete (HPC) and SFRC at 28-day and 56-day under the action of repeated dynamic loading was studied. Silica fume replacement at 10% and 15% by mass and crimped steel fiber ($V_f$ = 0.5%- 1.5%) with aspect ratios of 80 and 53 were used in the concrete mixes. Results indicated that addition of fibers in HPC can effectively restrain the initiation and propagation of cracks under stress, and enhance the impact strengths and toughness of HPC. Variation of fiber aspect ratio has minor effect on improvement in impact strength. Based on the experimental data, failure resistance prediction models were developed with correlation coefficient (R) = 0.96 and the estimated absolute variation is 1.82% and on validation, the integral absolute error (IAE) determined is 10.49%. On analyzing the data collected, linear relationship for the prediction of failure resistance with R= 0.99 was obtained. IAE value of 10.26% for the model indicates better the reliability of model. Multiple linear regression model was developed to predict the ultimate failure resistance with multiple R= 0.96 and absolute variation obtained is 4.9%.

The Impact of Corporate Social Responsibility on Brand Image: A Case Study in Vietnam

  • PHAN, Cuong Xuan;LE, Lam Van;DUONG, Duy;PHAN, Thuy Chung
    • The Journal of Asian Finance, Economics and Business
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    • v.8 no.4
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    • pp.423-431
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    • 2021
  • This paper examines the impact of university social responsibility on brand image and student satisfaction. Social responsibility impact on consumer behavior has been studied extensively. But the same impact has not been rigorously tested to the same extend in the education sector. Firstly, we analyze the perception of university social responsibility (USR) and its components, including (1) the quality of teaching programs, facilities, and academic staff; (2) supporting learning activities; and (3) human resource policies. Secondly, we investigate the relationship between university social responsibility, brand image, and student satisfaction. The study examined these relationships through a proposed economic model based on answers from a survey of 298 students at the University of Food Industry Ho Chi Minh City. From the above survey data, the author proceeds to quantify variables and, based on Cronbach's Alpha reliability coefficient, EFA factor analysis, and linear regression, to measure the impact of each social responsibility factor on business of the university and student satisfaction. The results show that university social responsibility actually affects the university's brand image and student satisfaction. Our findings suggest that universities should develop an appropriate marketing strategy to reinforce brand image and student satisfaction through the university social responsibility model.

Feasibility Study of Friction Characteristics for Impact Analysis (충돌 해석 시 마찰 모델 적용을 위한 기초 마찰 시험 연구)

  • Lee, Kwang-Hee;Lee, Chul-Hee
    • Tribology and Lubricants
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    • v.37 no.3
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    • pp.112-116
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    • 2021
  • Appropriate friction model usage is important for impact analysis because the relative motions between parts that are in contact for very short durations can vary greatly depending on the friction model. Vehicle seat components that have significant effects on impact analysis are also considered. This paper presents an experimental investigation of various material contact pairs to obtain the friction parameters of the Benson exponential friction model for impact simulation. The Coulomb friction model has limitations for impact analysis because of singularity at zero velocity. Metal/nonmetal materials are prepared, and friction tests are conducted for various sliding speeds, loads, and lubrication conditions. The obtained data are used in the friction model to implement finite element analysis. The parameters of the friction model are obtained by the curve-fitting method. The experimental results show that the friction coefficient with metal/nonmetal contact pairs is stable regardless of the working conditions. The friction model used in this study can also be applied for finite element analysis of the crash conditions, where the friction changes abruptly at the contact interface; the obtained friction parameters are also expected to be more accurate with more precise tests under different working conditions. These results can help improve the accuracy of the finite element analysis.

A Study on Improvement of Air Quality Dispersion Model Application Method in Environmental Impact Assessment (II) - Focusing on AERMOD Model Application Method - (환경영향평가에서의 대기질 확산모델 적용방법 개선 연구(II) - AERMOD 모델 적용방법을 중심으로 -)

  • Suhyang Kim;Sunhwan Park;Hyunsoo Joo;Minseop So;Naehyun Lee
    • Journal of Environmental Impact Assessment
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    • v.32 no.4
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    • pp.203-213
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    • 2023
  • The AERMOD model was the most used, accounting for 89.0%, based on the analysis of the environmental impact assessment reports published in the Environmental Impact Assessment Information Support System (EIASS) between 2021 and 2022. The mismatch of versions between AERMET and AERMOD was found to be 25.3%. There was the operational time discrepancy of 50.6% from industrial complexes, urban development projects between used in the model and applied in estimating pollutant emissions. The results of applying various versions of the AERMET and AERMOD models to both area sources and point sources in both simple and complex terrain in the Gunsan area showed similar values after AERMOD version 12 (15181). Emissions are assessed as 24-hour operation, and the predicted concentration in both simple and complex terrain when using the variable emission coefficient option that applies an 8-hour daytime operation in the model is lowered by 37.42% ~ 74.27% for area sources and by 32.06% ~ 54.45% for point sources. Therefore, to prevent the error in using the variable emission coefficient, it is required to clearly present the emission calculation process and provide a detailed explanation of the composition of modeling input data in the environmental impact assessment reports. Also, thorough reviews by special institutions are essential.

A Theoretical Study for the Formulation Design of PBX(I) (복합화약 조성설계에서의 이론적 연구(I))

  • Shim, Jung-Seob;Kim, Hyoun-Soo
    • Journal of the Korea Institute of Military Science and Technology
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    • v.11 no.2
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    • pp.109-115
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    • 2008
  • A Plastic Bonded Explosive(PBX) is mainly composed of nitramine explosive and polymer binder. The great number of serious applications of PBX requires the good adhesion between nitramine crystals and binder, which depends on the surface characteristics of a filler and binder. In the pursuit of the better design to achieve the enhanced adhesion, profound knowledge of the surface and interfacial characteristics of explosive and binder should be exploited. In this study, the influences of physicochemical properties between RDX and binders such as interfacial tension($\gamma_{SL}$), latent heat($Q_m$), and density($\rho$) on impact sensitivity of PBX were investigated. As experimental results, the major contribution factor to impact sensitivity of PBX was the interfacial tension, compare with other surface properties. The correlation coefficient of $H_{50}$ versus $\gamma_{SL}$ is 0.9932 when a polynomial regression method was used.

The Optimum Design according to System Variation of Impact Absorber for Spreader (스프레더용 충격흡수기의 시스템 변화에 따른 최적설계)

  • Seo, J.;Hong, D. K.;Kim, D. Y.;Ahn, C. W.;Han, G. J.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.05a
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    • pp.791-794
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    • 2002
  • On this study, the dynamic response of vibration absorber was operated by finite element analysis and this paper proposed the optimum value of spring constant and damping coefficient for three types of impact absorber. Also the reaction farce of piston which is the objective function was proposed by the optimum design and the model which has the optimum value among the reaction forces was shown.

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