• Geomechanics and Engineering
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• 제29권5호
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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 Biosystems Engineering
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• 제12권2호
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• pp.38-43
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• 1987

An experimental study was conducted to develop a thin-layer rewetting equation of short grain rough rice of Akihikari variety. Four thin-layer rewetting equations were experimentally determined from $25^{\circ}C$ to $45^{\circ}C$ and 70%RH to 85%RH conditions. Diffusion, Henderson, Page, and Thompson equations widely used as thin-layer drying equations were selected. Experimental data were fitted to these equations using linear regression analysis except diffusion equation. The diffusivity in the diffusion equation was determined by optimization method. Four equations were highly significant. In order to compare the goodness of fit of each equation, the error mean square of each equawas calculated. The diffusion model was not a very good model because the error mean square was very large. The other three models showed the same level or error mean square and could predict satisfactorily the rewetting rate or short grain rough rice.

• 소성∙가공
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• 제11권5호
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• pp.394-404
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• 2002

The drawbead model for a three-dimensional a finite element analysis of sheet metal forming processes is developed. The mathematical models of the basic drawbeads like circular drawbead, stepped drawbead, and squared drawbaed are first derived using the bending theory, belt-pulley equation, and Coulomb friction law. Next, the experiments for finding the drawing characteristics of the drawbead are performed. Based on mathematical models and drawing test results, expert models of basic drawbeads are then developed employing a linear multiple regression method. For the expert models of combined drawbeads such as the double circular drawbead, double stepped drawbead, circular-and-stepped drawbead, etc., those of the basic drawbeads are summed. Finally, in order to verify the expert models developed, the drawing characteristics calculated by the expert models of the double circular drawbead and circular-and-stepped drawbead are compared with those obtained from the experiments. The predictions by expert models agree well with the measurements by experiments.

• Preventive Nutrition and Food Science
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• 제4권2호
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• pp.85-87
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• 1999

A simple and rapid method to estimate the viscosity of chitosan using laboratory pipettes was developed. The voscosities of nine different chitosan samples, prepared ini 1 % acetic acid at a 1% concentration , were measured with a standard viscometer. Prior to measurement of flow time of 1% chitosan solution with a pipette, twelve pipettes were assorted into three groups with flow times of 4, 5 and 6 sec after measuring passage of 9 ml of 1% acetic acid througth a 10 ml pipette. With each group of pipettes. flow time of 1% chitosan solution was determined by measuring the delivery time of 5 ml of the 10ml solution through a 10 ml pipette. Results of regression analyses revealed high linear relationship(R2=0.9812, 0.9663, and 0.9754) between viscosities calculated with a viscometer and flow times measured with 4, 5 or 6 sec group pipettes. The viscosity of chitosan could be readily and accurately estimated from these linear regression equation by measuring flow times based on pipette delivery.

• 대한임상검사과학회지
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• 제45권2호
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• pp.54-59
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• 2013

NonHDL cholesterol values have been suggested as a risk marker for cardiovascular disease. NonHDL cholesterol values were calculated, using a very simple measurement [nonHDL cholesterol=serum total cholesterol-HDL cholesterol]. This formula is very useful as a screening tool for identifying dyslipoproteinemias, risk assessment, and assessing the results of hypolipidemic therapy. The data from the 2009 Korean National Health and Nutrition Examination Survey were used. Analysis was done for 1,992 subjects with lipid panels (Cholesterol, HDL, LDLdirect and Triglycerides) results. We studied the relationship between nonHDL cholesterol and LDL cholesterol. As a result, nonHDL cholesterol values were plotted against the LDL direct and calculated values. The linear regression equation for nonHDL cholesterol and direct LDL cholesterol was $nonHDLchol=23.60+1.03{\times}LDLdirect$ (p<0.0001, $r^2=0.80$) in all subjects. The subjects were classified into triglyceride values. When triglycerides are below 400 mg/dL, the linear fit to LDL direct is found to be $[nonHDLchol=17.34+1.07{\times}LDLdirect]$ (p<0.0001, $r^2=0.88$) and to the Friedewald LDL calculation is $[nonHDLchol=23.10+1.02{\times}LDLcalc]$ (p<0.0001, $r^2=0.82$). For triglycerides above 400 mg/dL, the linear fit equation is $[nonHDLchol=87.57+0.92{\times}LDLdirect]$ (p<0.0001, $r^2=0.50$) and to the LDL calculated, it is $[nonHDLchol=142.70+0.50{\times}LDLcalc]$ (p<0.0001, $r^2=0.32$). This study provides examples of the utility of nonHDL cholesterol concentrations in clinical medicine.

• 분석과학
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• 제16권3호
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• pp.185-190
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• 2003

회귀식 사용에 따른 불확도 계산의 정확성을 조사하기 위하여, 수정된 방법의 최소제곱법(Modified Least Square Method, MLS)과 회귀식에서 일반적으로 적용되는 불확도 처리 과정을 각각 1차 식에 적용하고 비교하였다. 회귀식에서 일반적으로 적용되는 불확도 처리 과정에서, 대부분의 경우 불확도 값이 크게 계산되고 있어 확률적으로 안전한 범위를 표기할 수 있는 것으로 평가되었다. 그러나, 표준시료 농도의 상대 표준불확도가 클 때 (교정점이 우발적으로 흩어지는 정도의 표준 편차가 5% 수준, 표준시료 농도의 상대 표준불확도가 7% 수준) 회귀식에서 일반적으로 적용되는 불확도 계산 방법으로 얻은 값이 고 농도 측정에서 매우 작게 평가되고 있어 확률적으로 매우 위험한 것으로 평가되었다. 이 경우, 통계학적으로 불확도를 정확히 계산하기 위하여, 수정된 방법의 최소제곱법이 유리하다고 판단하였다.

• 대한소아치과학회지
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• 제34권3호
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• pp.430-437
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• 2007

현재 혼합치열 분석 방법으로 가장 널리 사용되고 있는 Moyers의 예측표나 Tanaka와 Johnston의 예측방정식은 북유럽 인종의 백인 자료를 바탕으로 만들어졌기 때문에 한국인에게 적용하기에는 무리가 있다. 또한 최근에는 이들이 제시한 하악 전치에 기초한 방법이 미맹출 견치와 소구치 폭경의 합을 예측하기 위한 최적의 예측인자인지에 대해서도 의문이 제기되고 있다. 본 연구의 목적은 한국인 집단을 대상으로 미맹출 견치와 소구치의 근원심 폭경을 예측하기 위한 최적의 예측인자가 어떤 치아의 조합인지 밝히고, 그 조합을 이용한 예측 방정식을 제시하며, 새로운 예측 방정식의 임상 적용을 위해 그 타당성을 검증하는 것이다. 완전한 영구치열을 가진 성인 178명(남자 108명, 여자 70명, 평균 나이 21.63세)의 자료를 기초로 예측방정식을 도출하였으며, 53명의 청소년(남자 25명, 여자 28명, 평균 나이 14.22세)으로 검증집단을 구성하여 그 타당성을 검증하였다. 그 결과 다음과 같은 결론을 얻었다. 1. 한국인 혼합치열기 청소년에서 미맹출 견치와 소구치 폭경의 합을 예측하기 위한 최적의 치아 조합은 상악 중절치, 하악 측절치, 상악 제1대구치 폭경의 합이었다($r=0.65{\sim}0.80$). 2. 상악 중절치, 하악 측절치, 상악 제1대구치 폭경의 합을 기초로 하고 부가적인 설명 변수로 성별과 악궁을 포함시켜 계산한 예측 방정식은 다음과 같이 계산되었다. 남자, 상악: $Y\;=\;0.332{\times}X_0\;+\;6.195$ 남자, 하악: $Y\;=\;0.332{\times}X_0\;+\;5.269$ 여자, 상악: $Y\;=\;0.332{\times}X_0\;+\;5.929$ 여자, 하악: $Y\;=\;0.332{\times}X_0\;+\;5.003$ 예측 방정식의 설명력은 64%였으며 표준오차(SEE)는 0.71mm였다. 3. 새로운 예측 방정식을 검증 집단에 적용하여 검증한 결과, 약 97%에서 실제 측정한 견치와 소구치 폭경의 합과 예측치와의 차이가 1mm 이하였다.

• 한국수산과학회지
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• 제21권3호
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• pp.169-176
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• 1988

In order to obtain the objective indices which can assess the quality and the shelf-life of dried squid, nonenzymatic browning, carbonyl value, trimethyl amine (TMA) and trimethyl amine oxide (TMAO) decrease and panel test were determined in dried squid at various water activity levels. When the data of nonenzymatic browning fit a zero order equation, $r^2$ value were more than 0.92 except aw 0.52 for 0.8241. Through variance analysis for the data of browning extent and TMAO decrease, the confidence limits of regression equation were $99\%$ and their limit values of shelf-life were shown 0.45390 O. D./g. solid and 190.322 g/g respectively. In case of TMAO, $r^2$ value was calculated more than 0.95. Linear regression equation for the correlation between browning data and average panel score was Y=0.6138-0.053X and its $r^2$ value was 0.9285. Also in TMAO decrease, the equation was InY=2.0314+0.08269x and $r^2$ value was 0.7854. The shelf-life, evaluated by nonenzymatic browning, TMAO decrease and panel test, was 110-170 days at aw 0.45-0.76 except aw 0.15.

• 한국염색가공학회지
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• 제11권5호
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• pp.38-43
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• 1999

A calculation method of optimum parameters on dual adsorption isotherm system was examined. The optimum parameters were obtained by non-linear regression analysis based upon a limited solute concentration of dual adsorption isotherm. The results were analyzed with adducing experimental data of formerly reported treaties. The percentage mean deviation of dual adsorption equation calculated with optimum parameters was less than about 5% of experimental data, which was far less than results obtained with parameters of the adduced treatises.

• Bulletin of the Korean Chemical Society
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• 제22권4호
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• pp.388-394
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• 2001

Quantitative Structure-Activity Relationship (QSAR) have been established of 57 fluorovinyloxyacetamides compounds to correlate and predict EC50 values. Genetic algorithm (GA) and multiple linear regression analysis were used to select the descriptors and to generate the equations that relate the structural features to the biological activities. This equation consists of three descriptors calculated from the molecular structures with molecular mechanics and quantum-chemical methods. The results of MLR and GA show that dipole moment of z-axis, radius of gyration and logP play an important role in growth inhibition of barnyard grass.