• Asian-Australasian Journal of Animal Sciences
• /
• 제19권11호
• /
• pp.1551-1555
• /
• 2006

This study was carried out to investigate the use of three different mathematical models (Wood, Quadratic and Cubic) for describing the lactation curve of Akkaraman ewes. Data were collected from 42 ewes that were three years of age and from the same flock raised in The State Farm of $G{\ddot{o}}zl{\ddot{u}}$ in Konya Province. All ewes lambed in March. They were hand milked twice daily and the first milk test was performed with in the first month after lambing (mean = 27.8 day, SD = 4.26) in an attempt to describe the peak yield. The differences between estimated total milk yields by the models were not significant. The models were adequate for describing total milk yield. The differences between peak yields were not significant. The Wood model estimated the time of peak yield earlier than the other models and observed values (p<0.01). Especially the Cubic model's peak time was very close to really peak time (34.30 vs. 35.33 days). $R^2$ values of the models ranged from 85.85% to 96.20%. The Cubic model gave the best $R^2$ value (p<0.01). Correlation coefficients between descriptive values of the models changed from 0.32 to 1.00. Total milk yields of the models were highly correlated (above 0.99) with the total milk yield calculated by the Fleischmann method (p<0.01). As a result the Cubic model showed the best fit to the data collected from Akkaraman ewes and allowed a suitable description of the shape of the lactation curve.

• 대한교통학회지
• /
• 제27권6호
• /
• pp.89-96
• /
• 2009

본 연구는 고속도로 인터체인지와 이격거리가 아파트 가격에 미치는 영향관계를 정의하기 위하여 수행하였으며, 국외 선행연구고찰을 바탕으로 연구방향을 설정하였다. 자료수집의 일관성을 확보하기 위하여 세력권을 단순화시키고자 서울외곽순환고속도로의 인터체인지 내측(서울지역)과 외측(경기지역) 주변 최대 6.0km까지의 아파트가격을 조사하였다. 서울외곽순환고속도로 전체를 대상으로 분석한 결과 고속도로 인터체인지의 거리에 따라 아파트가격이 일정한 추세로 분포함을 알 수 있었다. 구체적으로 고속도로 인터체인지 세력권 전체적 측면의 아파트의 가격은 a) 상승하나 b) 인터체인지 인접지역은 상대적으로 감소하며 c) 약 2.0~4.0km에 가장 높은 가격을 보이다 d) 그 이후 인터체인지와 멀어지면서 급격히 감소하는 것을 알 수 있었다. 또한 고속도로 인터체인지 이격거리와 아파트 가격의 추세는 기존 철도(지하철)의 역세권이 가지는 (-)의 1차 선형이었던 것과는 대비되게 2차 형태의 곡선(Polynomial Curve)과 유사한 것을 알 수 있었다.

• Radiation Oncology Journal
• /
• 제24권4호
• /
• pp.280-284
• /
• 2006

목 적: 원자력의학원에 설치되어 있는 MC50 사이클로트론에서 생성되는 중성자선의 의학적 이용을 위하여 생물학적 특성을 평가하고자 하였다. 대상 및 방법: 35 MeV 양성자를 15 mm 베릴륨 표적에 부딪혀서 생성된 중성자선에 대하여 물리적 방사선선량을 측정한 후 체외실험(in-vitro)을 하였다. EMT-6 세포주(cell line)를 이용하여 $0{\sim}5\;Gy$의 중성자선을 조사 후 생존분획(surviving fraction)을 구하였다. 또한 감마선의 효과를 피하기 위하여 납차폐를 한 후에 동일 조건에서 생존분획을 구하였다. 엑스선 실험에서는 0, 2, 5, 10, 15 Gy를 조사 후 생존분획을 측정하였다. 결 과: MC50의 중성자선은 조사야 $26{\times}26\;cm^2$, 전류 $10{\mu}A$, 깊이 2 cm에서 84%의 중성자와 16%의 감마선으로 구성되어 있었고, 총선량률은 9.25 cGy/min이었다. 엑스선을 이용하여 측정한 생존분획곡선은 선형이차함수모델 (linear quadratic model)을 적용하였을 때 ${\alpha}/{\beta}$비는 0.611 (${\alpha}=0.0204,\;{\beta}=0.0334,\;R^2=0.999$)이었다. 중성자선에 있어서 생존분획곡선은 저선량 영역에서 어깨영역(shoulder area)을 가지고 있었고, 모든 실험에서 선형이차함수모델에 잘 맞았다. ${\alpha}$의 평균값은 -0.315 (범위, $-0.254{\sim}-0.360$)였고, ${\beta}$값은 0.247 (범위, $0.220{\sim}0.262$)이었다. 납차폐를 하였을 때에도 생존분획곡선에서 어깨영역은 없어지지 않았다. 중성자선의 RBE (relative biological effectiveness) 값은 생존분획이 0.1일 때 $2.07{\sim}2.19$ 범위였고, 0.01일 때 $2.21{\sim}2.35$였다. 결 론: MC50에서 생성된 중성자선은 상당량의 감마선을 내포하고 있으며 이것이 생존분획곡선에서 어깨영역이 나타나는 데에 기여하였을 것이다. MC50의 중성자선의 RBE 값은 약 2.2였다.

• ETRI Journal
• /
• 제35권5호
• /
• pp.915-918
• /
• 2013

This work presents an accurate finite-difference time-domain (FDTD) dispersive modeling of concrete materials with different water/cement ratios in 50 MHz to 1 GHz. A quadratic complex rational function (QCRF) is employed for dispersive modeling of the relative permittivity of concrete materials. To improve the curve fitting of the QCRF model, the Newton iterative method is applied to determine a weighting factor. Numerical examples validate the accuracy of the proposed dispersive FDTD modeling.

• 소성∙가공
• /
• 제11권1호
• /
• pp.75-83
• /
• 2002

Recently, the hydroforming process is widely applied to the automotive industry and rapidly spreaded to other industries. In this paper, An implicit finite element formulation for simulating axisymmetric tube hydroforming processes is performed. In order to describe normal anisotropy of the tube, Hill's non-quadratic yield function is employed. The frictional contact between die and tube and the frictionless contact between tube and fluid are considered using the mesh-normal vectors computed from the finite element mesh of the tube. The complete set of the governing relations comprising equilibrium and interfacial equations is linearized for Newton-Raphson procedure. In order to verify the validity of the developed finite element formulation, the axisymmetric tube bulge test is simulated and the simulation results are compared with experimental measurements. In a simulation of stepped circular tube hydroforming processes, an optimal hydraulic pressure curve is pursued by considering simultaneously internal pressures and axial forces.

• The Korean Journal of Ecology
• /
• 제18권2호
• /
• pp.265-273
• /
• 1995

Net photosynthetic rate (Pn) of Quercus mongolica leaves was determined under the controlled O₃concentrations of 0, 20, 30, 40, 50 or 60 ppb at every 10 min for 7 hr. Under the fumigation of the different O₃concentrations the relative net photosynthetic rate (RNPR) of the leaves decreased rapidly until 1 hr and thereafter decreased slowly. At below 20 ppb O₃the decrease of the RNPR was scarce but at above 20 ppb O₃the RNPR was inversely proportional to O₃concentration on a logarithmic curve. The RNPR at 60 ppb O₃, for example, was reduced 30％ less than that without O₃. Under the different O₃concentrations fumigated for the short period of time the Pn dependent upon PPFD was depicted as saturation equation and Pn dependent upon temperature as quadratic equation. Results of this study suggest that short-term low O₃of less than 60 ppb concentration may lead to reductions of Pn in Q. mongolica leaves.

• 한국유체기계학회 논문집
• /
• 제12권3호
• /
• pp.7-12
• /
• 2009

In this paper, shape optimization based on three-dimensional flow analysis has been performed for impeller design of centrifugal compressor. To evaluate the objective function of an isentropic efficiency, Reynolds-averaged Navier-Stokes equations are solved with SST (Shear Stress Transport) turbulence model. The governing equations are discretized by finite volume approximations. The optimization techniques based on the radial basis neural network method are used for the optimization. Latin hypercube sampling as design of experiments is used to generate thirty design points within design space. Sequential quadratic programming is used to search the optimal point based on the radial basis neural network model. Four geometrical variables concerning impeller shape are selected as design variables. The results show that the isentropic efficiency is enhanced effectively from the shape optimization by the radial basis neural network method.

• 한국경영과학회:학술대회논문집
• /
• 한국경영과학회/대한산업공학회 2005년도 춘계공동학술대회 발표논문
• /
• pp.842-847
• /
• 2005

Although there are many applications of Euclidean Voronoi diagram for spheres in a 3D space in various disciplines from sciences and engineering, it has not been studied as much as it deserves. In this paper, we present an edge-tracing algorithm to compute the Euclidean Voronoi diagram of 3-dimensional spheres in O(mn) in the worst-case, where m is the number of edges of Voronoi diagram and n is the number of spheres. After building blocks for the algorithm, we show an example of Voronoi diagram for atoms using actual protein data and discuss its applications for protein analysis.

• Journal of applied mathematics & informatics
• /
• 제6권2호
• /
• pp.669-684
• /
• 1999

We are interested in the problem of fitting a curve to a set of points in the plane in such a way that the sum of the squares of the orthogonal distances to given data points ins minimized. In[1] the prob-lem of fitting circles and ellipses was considered and numerically solved with general purpose methods. Especially in [2] H. Spath proposed a special purpose algorithm (Spath's ODF) for parabolas y-b=$c($\chi$-a)^2$ and for rotated ones. In this paper we present another parabola fitting algorithm which is slightly different from Spath's ODF. Our algorithm is mainly based on the steepest descent provedure with the view of en-suring the convergence of the corresponding quadratic function Q(u) to a local minimum. Numerical examples are given.

• Mass Spectrometry Letters
• /
• 제9권3호
• /
• pp.77-80
• /
• 2018

The focus of this paper is to present techniques to overcome certain difficulties in quantitative analysis with a time-of-flight mass spectrometer (TOF-MS). The method is based on conventional solid-phase extraction, followed by reversed-phase ultra high performance liquid chromatography of the extract, and mass spectrometric analysis. The target compounds included atenolol, atrazine, caffeine, carbamazepine, diclofenac, estrone, ibuprofen, naproxen, simazine, sucralose, sulfamethoxazole, and triclosan. The matrix effects caused by high concentrations of organic compounds in wastewater are especially significant in electrospray ionization mass spectroscopy. Internal-standard calibration with isotopically labeled standards corrects the results for many matrix effects, but some peculiarities were observed. The problems encountered in quantitation of carbamazepine and triclosan, due to nonlinear calibration were solved by changing the internal standard and using a narrower mass window. With simazine, the use of a quadratic calibration curve was the best solution.