• International Journal of Automotive Technology
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• v.7 no.6
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• pp.741-747
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• 2006

It has been almost impossible to predict the fatigue life in the field of rubber materials by numerical methods. One of the reasons is that there are no obvious fracture criteria and excessively various ways of mixing processes. Tearing energy is considered as a fracture criterion which can be applied to rubber compounds regardless of different types of fillers, relative to other fracture factors. Fatigue life of rubber materials can be approximately predicted based on the assumption that the latent defect caused by contaminants or voids in the matrix, imperfectly dispersed compounding ingredients, mold lubricants and surface flaws always exists. Numerical expression for the prediction of fatigue life was derived from the rate of rough cut growth region and the formulated tearing energy equation. Endurance test data for dumbbell specimens were compared with the predicted fatigue life for verification. Also, fatigue life of industrial rubber components was predicted.

• Journal of Welding and Joining
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• v.23 no.4
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• pp.17-26
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• 2005

HAZ (Heat Affected Zone) which occurs during welding thermal cycle has an important effect on the mechanical properties of the weld metal. So there were many efforts to develop the model which is able to predict the microstructure and mechanical properties in weld HAZ and lots of metallurgical models have reported since early 1940. These models are justifiable based on the reasonable assumption and analytical approach, but they also have limitation by interesting alloying system and assumption in each literature. Therefore, this study summaries the previous models for prediction of properties in weld HAZ. Then several issues to solve for developing the more reliable model were proposed.

• Publications of The Korean Astronomical Society
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• v.11 no.1
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• pp.263-277
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• 1996

We have intensively carried out numerical calculations on flare predictions from the solar activity data for photospheric sunspots, chromospheric flare and plages, coronal X-ray intensities and 2800MHz radio fluxes, by using multilinear regression method. Intensities of solar flares for the next day have been predicted from the solar data between 1977-1982 and 1993-1996. Firstly, we have calculated flare predictions with the multilinear regression method, by using separate solar data in growth and decay phase of sunspot area and magnetic field strength from the whole data on solar activities. Secondly, the same operations as above have been made for the remaining data after removal of the data with large deviation from the mean calculated by the above prediction method. we have reached a conclusion that average hit ratio of correct predictions to total predictions of flares with class of M5 over has been as high as 70% for the first case and that of correct prediction number to total observation number has been shown as 61%.

• Communications for Statistical Applications and Methods
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• v.28 no.3
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• pp.217-232
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• 2021

The Korea film industry has matured and the number of movie-watching per capita has reached the highest level in the world. Since then, movie industry growth rate is decreasing and even the total sales of movies per year slightly decreased in 2018. The number of moviegoers is the first factor of sales in movie industry and also an important factor influencing additional sales. Thus it is important to predict the number of movie audiences. In this study, we predict the cumulative number of audiences of films using stacking, an ensemble method. Stacking is a kind of ensemble method that combines all the algorithms used in the prediction. We use box office data from Korea Film Council and web comment data from Daum Movie (www.movie.daum.net). This paper describes the process of collecting and preprocessing of explanatory variables and explains regression models used in stacking. Final stacking model outperforms in the prediction of test set in terms of RMSE.

• Journal of Korean Society for Atmospheric Environment
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• v.28 no.3
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• pp.261-272
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• 2012

In this study, climate variability was predicted by the Weather Research and Forecasting (WRF) model under two different scenarios (current trends scenario; SC1 and managed scenario; SC2) for future urban growth over the Seoul metropolitan area (SMA). We used the urban growth model, SLEUTH (Slope, Land-use, Excluded, Urban, Transportation, Hill-Shade) to predict the future urban growth in SMA. As a result, the difference of urban ratio between two scenarios was the maximum up to 2.2% during 50 years (2000~2050). Also, the results of SLEUTH like this were adjusted in the Weather Research and Forecasting (WRF) model to analysis the difference of the future climate for the future urbanization effect. By scenarios of urban growth, we knew that the significant differences of surface temperature with a maximum of about 4 K and PBL height with a maximum of about 200 m appeared locally in newly urbanized area. However, wind speeds are not sensitive for the future urban growth in SMA. These results show that we need to consider the future land-use changes or future urban extension in the study for the prediction of future climate changes.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.8 s.179
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• pp.2074-2082
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• 2000

In this study, to investigate and to predict the crack growth behavior under variable amplitude loading, crack growth tests are conducted on 7075-T6 aluminum alloy. The loading wave forms are generated by normal random number generator. All wave forms have same average and RMS(root mean square) value, but different standard deviation, which is to vary the maximum load in each wave. The modified Forman's equation is used as crack growth equation. Using the retardation coefficient D defined in previous study, the load interaction effect is considered. The variability in crack growth process is described by the random variable Z which was obtained from crack growth tests under constant amplitude loading in previous work. From these, a statistical model is developed. The curves predicted by the proposed model well describe the crack growth behavior under variable amplitude loading and agree with experimental data. In addition, this model well predicts the variability in crack growth process under variable amplitude loading.

• Journal of Korean Society of Forest Science
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• v.112 no.2
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• pp.209-216
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• 2023

This study aimed to use national forest inventory data to develop a forest productivity index and yield prediction model of a Tilia amurensis stand. The site index displaying the forest productivity of the Tilia amurensis stand was developed as a Schumacher model, and the site index classification curve was generated from the model results; its distribution growth in Korea ranged from 8-16. The growth model using age as an independent variable for breast height and height diameter estimation was derived from the Chapman-Richards and Weibull model. The Fitness Indices of the estimation models were 0.32 and 0.11, respectively, which were generally low values, but the estimation-equation residuals were evenly distributed around 0, so we judged that there would be no issue in applying the equation. The stand basal area and site index of the Tilia amurensis stand had the greatest effect on the stand-volume change. These two factors were used to derive the Tilia amurensis stand yield model, and the model's determination coefficient was approximately 94%. After verifying the residual normality of the equation and autocorrelation of the growth factors in the yield model, no particular problems were observed. Finally, the growth and yield models of the Tilia amurensis stand were used to produce the makeshift stand yield table. According to this table, when the Tilia amurensis stand is 70 years old, the estimated stand-volume per hectare would be approximately 208 m³ . It is expected that these study results will be helpful for decision-making of Tilia amurensis stands management, which have high value as a forest resource for honey and timber.

• The Journal of the Korean dental association
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• v.15 no.6
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• pp.445-456
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• 1977

Author had experienced orthodontic cases that had been treated by the extraction of premolar at department of orthodontics, Tokyo Dental College. This report contains four cases which occlusion and profile were well improved by the orthodotic treatment. Four cases were all female. Two cases started orthodontic treatment at the age of puberty the other at adult. All the cases needed maximum anchorage. As a result, treatment were succeeded and profile was well advanced by growth and anchorage. In orthodontic treatment, the growth and anchorage are the KEY which lead to success. But the prediction of growth is very difficult.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.10
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• pp.49-55
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• 2000

This study describes the fatigue characteristics for Al2024 alloy, which is aircraft structure material. For this work, the plane-strain fracture toughness test, the plane-stress fracture toughness test and the crack growth rates test were conducted under the standard testing method. Test equipment is a computer-controlled closed-loop fatigue testing machine. The data of each test result is very important to aircraft structure reliability estimation, life prediction, design analysis, endurance analysis and damage tolerance analysis. In addition, the fatigue crack growth threshold($\DeltaKth$) value decreased as the stress ratio increased. Also, $\DeltaKth$ decreased as the thickness increased in LT, TL directions.

• Journal of Microbiology and Biotechnology
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• v.2 no.2
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• pp.129-134
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• 1992

Segregational instability of a recombinant plasmid, pDML6, encoding extracellular $\beta$-lactamase in Streptomyces lividans PD6 was characterized by growth kinetic analysis. The quantitative determination of the plasmid harbored in the mycelia was evaluated with mycelia fragmented mechanically, and also with colonies regenerated from protoplasts. Conditions for the formation of protoplasts and regeneration of protoplasts were established. The maximal specific growth rates of the host strain and the plasmid-harboring strain in a chemically defined medium without selection pressure were the same. The probability of plasmid loss from the harbouring cells was higher at higher growth rates. Mathematical models for the prediction of cell growth, substrate uptake, and accumulation of the cloned gene product were developed.