• Journal of Environmental Science International
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• v.11 no.4
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• pp.383-389
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• 2002

Odor sources of a chemical plant in Ulsan were surveyed and temperatures, humidities and flow rates of each exhaust gas were measured. The air samples collected from each source were transferred to the laboratory for sensory test and their odor concentrations were investigated. The odor emission rate of each source was estimated from the recorded results and assigned the sources expected to be needed for the odor prevention policy using the simple prediction equation of the affection by malodor to the nearest residential area. From the total odor emission rate of the examined plant and the relation table for expectable affection area it was concluded that total odor emission of this plant might be decreased for the prevention of residential complaint.

• 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.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.5
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• pp.1349-1355
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• 1990

By examining the fatigue deformation properties of 12% Cr rotor steel which has been proved to have high fatigue and creep rupture strength around 600deg. C, authors reviewed major fatigue life prediction models such as Manson, Langer and Morrow equations, and following results were obtained. (1) A simple life prediction model for 12% Cr rotor steel was obtained as follows : DELTA..epsilon.$_{t}$ =2.18+.sigma.$_{u}$ /E+ $N^{-0.065}$+ $e^{0.6}$ $N^{-0.025}$ This equation shows that fatigue life, N, can be easily determined when total strain range, DELTA..epsilon.$_{t}$ and ultimate tensile strength, .sigma.$_{u}$ are known by simple tension test on the given test conditions. (2) Life prediction equation with equivalent maximum stress, DELTA..sigma./2, corresponding maximum strain in one cycle at room temperature is as follows: DELTA..sigma./w=-7.01logN+96.69+96.69

• Journal of the Korean Geotechnical Society
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• v.27 no.9
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• pp.55-66
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• 2011

The compulsory replacement method for soft ground treatment is simple but excellent in economic feasibility. However, the accurate replacement depth is not easy to properly predicted since an theoretical algorithm has not presently been established so far. In this research a prediction equation is proposed in a new form based on the liquid limit and natural moisture content rather than on the bearing capacity of the soft soil layer. The equation is based on the monitoring as well as the confirmatory boring at the site. In addition, the equation has been derived from the data obtained from the analysis of the characteristics of silt/clay of Sihwa region. The final prediction equation has been drawn by applying the regression analysis method.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.603-608
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• 2008

A simple equation to find a optimum speed of desiccant rotor is presented in this theoretical study. Usually the determination of optimum speed of desiccant rotor requires tedious and lengthy procedures by solving governing differential equations with many complicated parameters. The determining equation of optimal rotating speed is derivated from governing differential equations with three linearization assumptions, which simplify temperature profile linear along the desiccant rotor depth, psychrometric chart within a proper range, and relative humidity-sorption capacity relation. This study shows that the dominant parameters of optimal rotating speed of desiccant rotor are NTU, flow velocity, desiccant rotor depth, and temperature different between dehumidification and regeneration. The comparison shows the good agreement between complicated calculation results and simple theoretical equation prediction.

• Proceedings of the Korea Concrete Institute Conference
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• 1993.04a
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• pp.124-129
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• 1993

In this study, a simple and accurate model equation for prediction of shear strength of reinforce concrete beams without web, reinforcement is proposed based on basic shear transfer mechanism and modified Bazant's size effect law. The proposed equation includes the effects of concrete strength, longitudinal steel ratio, shear span to depth ratio and effective depth. Comparisons with published experimental data indicate that the proposed equation estimates properly the effects of these factors. Among many equations, ACI code equation, Zsutty's equation and Bazant's equation are selected for comparison. As the result, the accuracy of the proposed equation is better than that of any other equations.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1990.10a
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• pp.53-58
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• 1990

The use of spreadsheet packages for solving noise control problems has been cited by several authors, eg Saha[1] and Thornton[2]. The effectiveness of using spreadsheet packages compared with the traditional computer programs written in high level languages was demonstrated when applied to relatively simple problems, such as the selection of hearing protectors or the prediction of noise equation which includes logarithmic additions at most represents the physics of the problem. The simplicity of the governing equation together with the requirement to handle a vast amount of data are considered to be the major reasons for noise control engineers to use spreadsheet packages. Although shipboard noise prediction seems to be very complicated, the calculation procedure itself is, in essence, identical especially true for prediction methods based on empirical formulae[3,4], ie the procedure that consists of the three basic elements, ie source, path and receiver. This paper discusses the application of spreadsheet package LOTUS 1-2-3 to shipboard noise prediction problems. A utility program of the package is written using macro functions and is shown to be especially useful for noise control engineers who are unfamiliar with spreadsheet packages. In addition, a new type of empirical formula, to estimate structureborne noise transmission loss, is proposed.

• Journal of the korean Society of Automotive Engineers
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• v.9 no.1
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• pp.69-76
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• 1987

This paper deals with the theoretical prediction and cyclic variation of combustion characteristics in a four stroke, single0cylinder, diesel engine. Theoretical calculations employed a simple empirical model of analysis of energy equation for the thermodynamic system of engine cylinder. The cyclic variation of combustion characteristics is investigated, in term of frequency distribution and standard deviation of peak characteristics, as obtained by combustion analyzer system. The results of theoretical prediction are shown to be in close agreement with the experimental data. The effect of fuel injection timing, engine speed, cooling water temperature, and the compression ratio on the cyclic variations of combustion characteristics were discussed.

• Aerospace Engineering and Technology
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• v.11 no.1
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• pp.169-177
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• 2012

This paper considers the explicit guidance algorithm to determine the closed-loop guidance law applicable to upper stages of a given space launch vehicle. It has the advantage of very simple forms derived from the flat earth assumption, which is appropriate for its on-board application. However the simple time-to-go prediction equation produces the degraded guidance performance of the launcher because of its inaccuracy. To overcome the problem, the elaborate prediction equations, which have been employed in Saturn and H-II, are attempted here. Finally, the simulation results show that the simple guidance approach requires the more accurate time-to-go prediction and gravity integrals for its broad application.

• Journal of the Korea Institute of Military Science and Technology
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• v.12 no.2
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• pp.139-145
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• 2009

This paper includes that there is the way to make the prediction of the remaining life of the barrel in small arms using analyzing dispersion. There are some ways to know the period to change the barrel such as the method of detecting the inner surface directly or inspecting the scratch using the optical sensor. However, it is a more easy way to check the dispersion for soldiers and the directors in a logistics command. Therefore, this study is conducted to focusing on the relation between firing round and dispersion. And the simple equation experimentally derives from pre-tests and analyses. Also, this equation is confirmed through the firing tests during the period of developing K11. In that sense, it can be easily applied to know the period of changing the barrel of small arms in the field army.