• Geomechanics and Engineering
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• v.29 no.5
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• pp.523-533
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• 2022

Several prediction model of penetration rate (PR) of tunnel boring machines (TBMs) have been focused on applying to design stage. In construction stage, however, the expected PR and its trends are changed during tunneling owing to TBM excavation skills and the gap between the investigated and actual geological conditions. Monitoring the PR during tunneling is crucial to rescheduling the excavation plan in real-time. This study proposes a sequential prediction method applicable in the construction stage. Geological and TBM operating data are collected from Gunpo cable tunnel in Korea, and preprocessed through normalization and augmentation. The results show that the sequential prediction for 1 ring unit prediction distance (UPD) is R²≥0.79; whereas, a one-step prediction is R²≤0.30. In modeling algorithm, a gradient boosted regression tree (GBRT) outperformed a least square-based linear regression in sequential prediction method. For practical use, a simple equation between the R² and UPD is proposed. When UPD increases R² decreases exponentially; In particular, UPD at R²=0.60 is calculated as 28 rings using the equation. Such a time interval will provide enough time for decision-making. Evidently, the UPD can be adjusted depending on other project and the R² value targeted by an operator. Therefore, a calculation process for the equation between the R² and UPD is addressed.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.4
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• pp.55-62
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• 2018

Problems on vibration due to blasting for infrastructure development are getting important because of a civil appeal. Blasting-induced vibration is representative construction pollution, hence, it is possible that a number of environmental damages occur. In this study, borehole test blasting was conducted at Sintanjin area, Daejeon and square root equation with 95% confidence level was proposed for prediction of blasting-induced vibration. The vibration value predicted from this equation was more conservatively evaluated than the values predicted from U.S. Department of Interior, Bureau of Mines (USBM) and Nippon Oil & Fats Co., Ltd. (NOF) equations. Therefore, the proposed equation in this study seems to contribute for safety blast design. However, for optimal blast design, inducing equation for prediction of blasting-induced vibration through the identical test blasting with field construction such as rock slope blasting would be required.

• Journal of the Korean Solar Energy Society
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• v.33 no.3
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• pp.114-123
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• 2013

In these days, most of the office buildings are being required to save energy for maintenance. lighting system constitutes 20% to 30% of the total annual electrical energy consumption in office buildings. As an energy saving strategy for lighting system, dimming control system based on illuminance sensors came into use. But the system is accompanied with many illuminance sensors to control lighting and needs a lot of initial investment. In this study, the prediction equation for indoor daylighting illuminance distribution is proposed through the review for conventional research results and field measurements. The proposed equation was verified by the comparison between predicted results and field measurement results. The developed prediction equation for daylighting can be used to control the indoor illuminance level with the limited sensor when dimming control system is operated.

• The Journal of Engineering Geology
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• v.19 no.3
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• pp.409-415
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• 2009

Kozeny-Carman equation has been generally applied to prediction of permeability for soil. The Kozeny-Carman equation has indicated fairly good results in prediction of sandy soils, but it is known that the equation is not appropriate for fine-grained soils such as cohesive soils. Therefore, a theoretical equation based on Kozeny-Carman equation is proposed to predict of permeability for cohesive soils in this paper. To develop the theoretical equation, soil properties of cohesive soil existed in the coastal areas and compacted cohesive soil used for the core of a dam were investigated and analyzed. As the results of this limited study, the most related factors between soil properties and permeability were #200 passing percentage for compacted cohesive soil, and clay content for cohesive soil at the coast areas.

• Particle and aerosol research
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• v.19 no.4
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• pp.145-154
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• 2023

Granular bed filters are widely used to remove particulate matter in flue gas and are filled with various shapes of packing material. The packing material plays an important role in determining the overall collection performance, such as pressure drop and collection efficiency. The pressure drop of a granular bed filter has been calculated using the Ergun equation, while the collection efficiency has been predicted using the log-penetration equation based on the single sphere theory. However, a prediction equation of collection efficiency for a granular bed filter filled with non-spherical packing materials has not been suggested yet. Therefore, in this study, three different shapes of packing materials (sphere, cylinder, and irregular) were prepared to propose a prediction equation. The pressure drop and collection efficiency in a granular bed filter filled with each shape of packing material were measured experimentally and compared with theoretically predicted values. We found that experimentally measured pressure drops matched well with values theoretically predicted using the Ergun equation considering the shape factor. However, experimental collection efficiencies were higher than theoretical ones predicted by the log-penetration equation using the single sphere theory. We modified the log-penetration equation by employing a shape factor and found a good relationship between experimental and theoretical collection efficiencies.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.1 no.1
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• pp.133-140
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• 2002

The object of this paper is to predict the surface roughness using the experiment equation of surface roughness, which is developed with a full factorial design in turning. $3^3$ full factorial design has been used to study main and interaction effects of main cutting parameters such as cutting speed, feed rate, and depth of cut, on surface roughness. For prediction of surface roughness, the arithmetic average (Ra) is used, and stepwise regression has been used to check the significance of all effects of cutting parameters. Using the result of these, the experimental equation of surface roughness, which consists of significant effects of cutting parameters, has been developed. The coefficient of determination of this equation is 0.9908. And the prediction ability of this equation was verified by additional experiments. The result of that, the coefficient of determination is 0.9718.

• Fire Science and Engineering
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• v.17 no.2
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• pp.50-55
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• 2003

The lower flash points for the binary system, n-butanol+n-decane, were measured by Pensky-Martens closed cup tester. The experimental results showed the minimum in the flash point versus composition curve. The experimental data were compared with the values calculated by the reduced model under an ideal solution assumption and the flash point-prediction models based on the Van Laar and Wilson equations. The predictive curve based upon the reduced model deviated form the experimental data for this system. The experimental results were in good agreement with the predictive curves, which use the Van Laar and Wilson equations to estimate activity coefficients. However, the predictive curve of the flash point prediction model based on the Willson equation described the experimentally-derived data more effectively than that of the flash point prediction model based on the Van Laar equation.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.105-108
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• 2007

Recently, due to the high interests for well being life, claims about noise ad vibration are increased very rapidly. Therefore more reliable and exact evaluation of noise impact has been required. Until now in Korea, only one prediction equation for the assessment of railway environmental noise was used. But that equation has many limits and weak points because of the update was not performed from 1993. So in this study, the performance of another equation proposed by authors was compared to the former. As a result, proposed prediction equation may be used to evaluate the impact of railway noise in the future.

• Proceedings of the Korea Concrete Institute Conference
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• 1995.10a
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• pp.124-128
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• 1995

It is the "maturity rule" that concrete of the same mix, at the same maturity, has the same strength. In this study, the Nurse-Saul function which was proposed to account for the effects of temperature and time on strength development is used in computing maturity. After existing various functions to relate concrete strength to the maturity value are considered, new strenth-maturity function is proposed. Tests are conducted in order to compare prediction value with measured concrete strength. The constants in proposed prediction equation are determined by standard specimens(cylinders) test, and the equation is adopted to predict strength of slab. The slab was cast in the laboratory from the same batch of mole, and cores are cut from slab in order to estimate the actual strength. Tehese values are used to compare with proposed equation. equation.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.366-371
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• 2004

For the reduction and efficient management of railway noise, first of all prediction of railway noise is necessarily requisted. At home and abroad many studies for prediction of raiiway nearby noise have been accomplished. But it is impossible to predict easily and exactly for the Korean Railway, because the acoustic powers for each rolling stock operated in Korea have not been built yet. So in this study, prediction model equation for environmental noise for Korean rolling stock Mugungwha was suggested using SEL of engine and rolling noise component separately. In this prediction model, the number of car, distance from the rail can be considered. Finally for the validation of prediction nlodel equation, the predicted Leq was compared to the measured Leq.