• Journal of Mechanical Science and Technology
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• 제15권1호
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• pp.44-51
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• 2001

One of the recent issues in design of the spot-welded structure such as the automobile body is to develop an economical prediction method of the fatigue design criterion without additional fatigue test. In this paper, as one of basic investigation for developing such methods, fracture mechanical approach was investigated. First, the Model I, Mode II and Mode III, stress intensity factors were analyzed. Second, strain energy density factor (S) synthetically including them was calculated. And finally, in order to decide the systematic fatigue design criterion by using this strain energy density factor, fatigue data of the ΔP-N(sub)f obtained on the various in-plane bending type spot-welded lap joints were systematically re-arranged in the ΔS-N(sub)f relation. And its utility and reliability were verified by the theory of Weibull probability distribution function. The reliability of the proposed fatigue life prediction value at 10(sup)7 cycles by the strain energy density factor was estimated by 85%. Therefore, it is possible to decide the fatigue design criterion of spot-welded lap joint instead of the ΔP-N(sub)f relation.

• 한국식품과학회지
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• 제20권2호
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• pp.133-139
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• 1988

액체 식품의 밀도를 예측할 수 있는 모델을 온도와 그 식품의 주요성분의 조성의 함수로 발전시키기 위하여 액체식품의 주요성분을 다음과 같이 water, protein, fat, carbohydrate, fiber, ash등 6가지 성분으로 분류하였고, 다시 세분하면 16가지의 주요성분을 분리 준비하여 그중 분말로 준비된 시료는 증류수를 사용하여 3종류의 서로 다른 농도의 현탁액을 만들어서 volumetric pycnometer를 사용하여 $0^{\circ}C$에서 $100^{\circ}C$의 온도범위에서 밀도를 측정하였다. 측정된 값으로부터 주어진 온도에서 각 순수성분의 밀도를 계산하였으며 이때 순수한 성분의 밀도는 온도의 증가에 따라 1차 함수의 관계로 감소한다는 사실을 알게 되었다. 계산된 밀도값으로부터 $0^{\circ}C$에서 $100^{\circ}C$의 온도범위에서 각 순수성분의 밀도 예측 모델의 계수를 OPT subroutine을 사용하여 결정하였다. 그리하여 Table 14 혹은 Table 15에 나타난 식을 활용하여 주어진 온도와 조성에서 액체식품의 밀도를 예측할 수 있을 것으로 사료된다.

• 한국염색가공학회지
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• 제19권6호
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• pp.7-11
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• 2007

A prediction model for yarn density profile was developed using the neural network methodology. The neural network model developed traces mass densities of a yarn within a section and predicts the mass profiles of the next yarn segment yet to be measured. The model does not require an assumption on the existence of a relationship between the past and future data sets. Four high-draft yarns made under different processing conditions were employed in order to test the performance of the model developed. It was shown that the model could predict the yarn density profiles without a significant error.

• Environmental Engineering Research
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• 제10권1호
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• pp.15-21
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• 2005

A computer program is developed for the prediction of the flow pattern and the removal efficiency of suspended solid (SS) in a circular secondary clarifier. In this study the increased density effect by SS on hydrodynamics has been systematically investigated in terms of Froude Number (Fr), baffle existence, and a couple of important empirical models associated with the particle settling and Reynolds stresses. A control-volume based-finite difference method by Patankar is employed together with the SIMPLEC algorithm for the resolution of pressure-velocity coupling. The k-ε turbulence and its modified version are incorporated for the evaluation of Reynolds stresses. The calculation results predicts well the overall flow pattern such as the waterfall phenomenon at the front end of the clarifier and the bottom density current with the formation of strong recirculation especially for the case of decrease of Fr. Even if there are some noticeable differences in the prediction of two turbulence models, the calculated results of the radial velocity profiles are generally in good agreement against experimental data appeared in open literature. Parametric investigation has been systematically made with the Fr and baffle condition with detailed analysis.

• 한국분무공학회지
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• 제26권4호
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• pp.171-181
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• 2021

This study presents a prediction methodology of thermodynamic properties by using RK-PR Equation of State in a wide range of temperature and pressure conditions including both sub-critical and super-critical regions, in order to obtain thermophysical properties for hydrocarbon aviation fuels and their products resulting from endothermic reactions. The density and the constant pressure specific heat are predicted in the temperature range from 300 to 1000 K and the pressure from 0.1 to 5.0 MPa, which includes all of the liquid and gas phases and the super-critical region of three representative hydrocarbon fuels, and then compared with those data obtained from the NIST database. Results show that the averaged relative deviations of both predicted density and constant pressure specific heat are below 5% in the specified temperature and pressure conditions, and the major sources of the errors are observed near the saturation line and the critical point of each fuel.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1998년도 춘계학술대회논문집
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• pp.168-174
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• 1998

In the present study, a method for measuring the relative density by the hardness measurement was proposed for sintered metal powder compacts. It is based on the indentation force equation, by which the relative density is related with the hardness, that was obtained by the finite element analysis of rigid-ball indentation on sintered metal powder compacts. For verifying the method, it was applied to prediction of density distributions in sintered and sintered-and-forged Fe-0.5%C-2%Cu powder compacts.

• 한국해양공학회지
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• 제28권5호
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• pp.396-403
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• 2014

This paper considered the prediction of the tension force in the design of a TLP tendon, particularly focusing on the springing problem. Springing is an important parameter that exerts a large tension in special cases. It is a nonlinear phenomenon and requires the 2nd-order wave loads to solve. In this paper, a new prediction method for springing and the resultant extreme tension on the tendon of a TLP is introduced. Using the 2nd-order response function computed using the commercial program WADAM, the probability density function of the 2nd-order tension is obtained from an eigenvalue analysis using a quadratic transfer function and sea spectra. A new method is then suggested to predict the extreme tension loads with respect to the number of occurrences. It is shown that the PDF suggested in this study properly predicts the extreme tension in comparison with the time histories of the 2nd-order tension. The expected tension force is larger than that from a linear analysis in the same time windows. This supports the use of the present method to predict the tension due to springing.

• 한국추진공학회지
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• 제26권5호
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• pp.1-10
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• 2022

로켓엔진용으로 개발된 구리크롬 합금에 대해 저주기 피로시험을 수행하고 여러가지 피로수명 예측방법을 이용해 예측수명을 구하여 이를 시험수명과 비교하여 보았다. 피로수명 예측방법으로는 Coffin-Manson 관계식, 소성 및 전 변형률 에너지 밀도 관계식, Smith-Watson-Topper 관계식, Tomkins 관계식, Jahed-Varvani 관계식 등 총 6가지 방법을 이용하였다. 피로 예측수명을 계산한 결과 모든 방법에서 시험수명 대비 분산범위 2 이내를 만족하였다. 예측수명 편차의 정량적 확인을 통해 전 변형률 에너지 밀도 관계식이 가장 우수한 결과를 나타냈다.

• Journal of the Korean Data and Information Science Society
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• 제13권1호
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• pp.139-145
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• 2002

This paper deals with the problem of obtaining the Bayesian predictive density function and the prediction intervals for a future observation and the p-th order statistics of n future observations for the exponential model under the censored sampling with incomplete information.

• Communications for Statistical Applications and Methods
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• 제20권6호
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• pp.427-438
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• 2013

Based on progressive Type II censored sampling which is an important method to obtain failure data in a lifetime study, we suggest a very general form of Bayesian prediction bounds from two parameters exponentiated Weibull distribution using the proper general prior density. For this, Markov chain Monte Carlo approach is considered and we also provide a simulation study.