• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.3
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• pp.1471-1477
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• 2014

This paper addresses the development on supply-demand outlook model of Jeju winter radish and introduces a projection of supply-demand and market prices during 2014-2018 using the model. The supply-demand outlook model is specified as a partial equilibrium model of Jeju winter radish. Each equation in the model is estimated by using the econometric techniques. A review of the model stability is also carried out by the references based on RMSPE, MAPE, and Theil's inequality coefficients. According to the reference of RMAPE, the error rates of the forecasting values of the cultivation ares, production quantity, and consumption quantity show less than 4% and the error rate of market price is below 10%. The cultivation area and production quantity are projected respectively to be increased to 6,650ha and 433,310MT in 2018.

• Food Science of Animal Resources
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• v.28 no.1
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• pp.63-68
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• 2008

To develop the somatic cell counting NIR Spectrum method within a range of 400-2500 nm, eosin-Y, methyl red, methylene blue, resazurin and amido black 10B were tested at 0.01% in raw milk. The PLS (Partial Least Square) results are summarized as follows: Correlation coefficients of the calibration model measurements by NIR spectroscopy in raw milk for eosin-Y, methyl red, methylene blue, resazurin and amido black 10B were 0.78, 0.65, 0.63, 0.65, 0.98 and 0.99, respectively. The correlation coefficients of the prediction model measurements by NIR spectroscopy in raw milk for eosin-Y, methyl red, methylene blue, resazurin and amido black 10B were 0.49, 0.21, 0.36, 0.47, 0.95 and 0.98 respectively. Based on these results, amido black 10B was the best additive for the NIRS somatic cell count method.

• Journal of the Korean institute of surface engineering
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• v.39 no.5
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• pp.240-244
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• 2006

Tribaloy 800 (T800) powder is coated on the Inconel 718 substrate by the optimal High Velocity Oxy-Fuel (HVOF) thermal spray coating process developed by this laboratory. For the study of the possibility of replacing of the widely used classical chrome plating, friction, wear properties and sliding wear mechanism of coatings are investigated using reciprocating sliding tester both at room and at an elevated temperature of $1000^{\circ}F\;(538^{\circ}C). Both at room temperature and at $538^{\circ}C$, friction coefficients and wear debris of coatings are drastically reduced compared to those of non-coated surface of Inconel 718 substrate. Friction coefficients and wear traces of both coated and non-coated surfaces are drastically reduced at higher temperature of $538^{\circ}C$ compared with those at room temperature. At high temperature, the brittle oxides such as $CoO,\;Co_3O_4,\;MoO_2,\;MoO_3$ are formed rapidly on the sliding surfaces, and the brittle oxide phases are easily attrited by reciprocating slides at high temperature through complicated mixed wear mechanisms. The sliding surfaces are worn by the mixed mechanisms such as oxidative wear, abrasion, slurry erosion. The brittle oxide particles and melts and partial-melts play roles as solid and liquid lubricant reducing friction coefficient and wear. These show that the coating is highly recommendable for the durability improvement coating on the surfaces vulnerable to frictional heat and wear.

• Journal of the Korea Society of Computer and Information
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• v.19 no.11
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• pp.17-24
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• 2014

This paper proposes a fault detection method for low-speed rolling element bearings of an induction motor using acoustic emission signals and histogram modeling. The proposed method performs envelop modeling of the histogram of normalized fault signals. It then extracts and selects significant features of each fault using partial autocorrelation coefficients and distance evaluation technique, respectively. Finally, using the extracted features as inputs, the support vector regression (SVR) classifies bearing's inner, outer, and roller faults. To obtain optimal classification performance, we evaluate the proposed method with varying an adjustable parameter of the Gaussian radial basis function of SVR from 0.01 to 1.0 and the number of features from 2 to 150. Experimental results show that the proposed fault identification method using 0.64-0.65 of the adjustable parameter and 75 features achieves 91% in classification performance and outperforms conventional fault diagnosis methods as well.

• Korean Journal of Agricultural Science
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• v.45 no.4
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• pp.823-837
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• 2018

The objective of this study was to evaluate the firmness and the sweetness index (SI) of tomatoes with a hyperspectral imaging (HSI) technique within the wavelength range of 1000 - 1550 nm. The hyperspectral images of 95 tomatoes were acquired with a push-broom hyperspectral reflectance imaging system, from which the mean spectra of each tomato were extracted from the regions of interest. The reference firmness and sweetness index of the same sample was measured and calibrated with their corresponding spectral data by partial least squares (PLS) regression with different preprocessing methods. The calibration model developed by PLS regression based on the Savitzky-Golay second-derivative preprocessed spectra resulted in a better performance for both the firmness and the SI of the tomatoes compared to models developed by other preprocessing methods. The correlation coefficients ($R_{pred}$) were 0.82, and 0.74 with a standard error of prediction of 0.86 N, and 0.63, respectively. Then, the feature wavelengths were identified using a model-based variable selection method, i.e., variable importance in projection, from the PLS regression analyses. Finally, chemical images were derived by applying the respective regression coefficients on the spectral image in a pixel-wise manner. The resulting chemical images provided detailed information on the firmness and the SI of the tomatoes. The results show that the proposed HSI technique has potential for rapid and non-destructive evaluation of firmness and the sweetness index of tomatoes.

• Steel and Composite Structures
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• v.48 no.2
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• pp.113-130
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• 2023

The present manuscript aims to investigate the deviation between the middle surface (MS) and neutral surface (NS) formulations on the static response of bi-directionally functionally graded (BDFG) porous plate. The higher order shear deformation plate theory with a four variable is exploited to define the displacement field of BDFG plate. The displacement field variables based on both NS and on MS are presented in detail. These relations tend to get and derive a new set of boundary conditions (BCs). The porosity distribution is portrayed by cosine function including three different configurations, center, bottom, and top distributions. The elastic foundation including shear and normal stiffnesses by Winkler-Pasternak model is included. The equilibrium equations based on MS and NS are derived by using Hamilton's principles and expressed by variable coefficient partial differential equations. The numerical differential quadrature method (DQM) is adopted to solve the derived partial differential equations with variable coefficient. Rigidities coefficients and stress resultants for both MS and NS formulations are derived. The mathematical formulation is proved with previous published work. Additional numerical and parametric results are developed to present the influences of modified boundary conditions, NS and MS formulations, gradation parameters, elastic foundations coefficients, porosity type and porosity coefficient on the static response of BDFG porous plate. The following model can be used in design and analysis of BDFG structure used in aerospace, vehicle, dental, bio-structure, civil and nuclear structures.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.20 no.4
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• pp.355-362
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• 2008

A reliability model of Level II AFDA is proposed to analyze the wave run-up occurring by the interaction of incident waves and sloped coastal structures. The reliability model may be satisfactorily calibrated by Level III Monte-Carlo simulation. Additionally, the partial safety factors of random variables related to wave run-up can be straightforwardly evaluated by the inverse-reliability method that use influence coefficients and uncertainties of random variables, and target probability of failure. In particular, a design equation for wave run-up is derived in the same form as that of deterministic design method so that the reliability-based design method of Level I may be applied easily. Finally, it is confirmed that results redesigned by the reliability-based design method of Level I with partial safety factors suggested in this paper are satisfactorily compared with results of CEM(2006) as well as those of Level II AFDA.

• The Korean Journal of Community Living Science
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• v.27 no.1
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• pp.5-17
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• 2016

The purpose of this study was to examine the mediating effects of young children's shyness on the relationship between teacher-children relationship and young children's social competence. The subjects of the study were 270 children from three years to five years old and their teachers in Busan. Frequency, t-test, Cronbach ${\alpha}$, Pearson's correlation coefficients, and hierarchial regression were used for data analysis. The results were as follows: first, teacher-children intimacy showed positive correlation with the young children's social competence. Teacher-children conflict showed negative correlation with the young children's social competence. Second, teacher-children intimacy showed negative correlation with the young children's shyness. Teacher-children conflict showed positive correlation with the young children's shyness. Third, young children's shyness showed negative correlation with the young children's social competence. Fourth, young children's shyness had partial mediating effects on the relationship between teacher-children intimacy and young children's sociability. Young children's shyness had partial mediating effects on the relationship between teacher-children intimacy and young children's popularity and leadership. Young children's shyness had partial mediating effects on the relationship between teacher- children conflict and young children's sociability. Young children's shyness had partial mediating effects on the relationship between teacher-children conflict and young children's popularity and leadership.

• Structural Engineering and Mechanics
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• v.7 no.2
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• pp.181-202
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• 1999

Dynamic response of axisymmetric arbitrary laminated composite cylindrical shell of finite length, using three-dimensional elasticity equations are studied. The shell is simply supported at both ends. The highly coupled partial differential equations are reduced to ordinary differential equations (ODE) with variable coefficients by means of trigonometric function expansion in axial direction. For cylindrical shell under dynamic load, the resulting differential equations are solved by Galerkin finite element method, In this solution, the continuity conditions between any two layer is satisfied. It is found that the difference between elasticity solution (ES) and higher order shear deformation theory (HSD) become higher for a symmetric laminations than their unsymmetric counterpart. That is due to the effect of bending-streching coupling. It is also found that due to the discontinuity of inplane stresses at the interface of the laminate, the slope of transverse normal and shear stresses aren't continuous across the interface. For free vibration analysis, through dividing each layer into thin laminas, the variable coefficients in ODE become constants and the resulting equations can be solved exactly. It is shown that the natural frequency of symmetric angle-ply are generally higher than their antisymmetric counterpart. Also the results are in good agreement with similar results found in literatures.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.758-761
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• 2004

This paper proposes a design and implementation of multiplierless digital PID (Proportional-Integral-Derivative) controller using FPGA (Field Programmable Gate Array) for controlling the speed of DC motor in digital system. The multiplierless PID structure is based on Distributed Arithmetic (DA). The DA is an efficient way to compute an inner product using partial products, each can be obtained by using look-up table. The PID controller is designed using MATLAB program to generate a set of coefficients associated with a desired controller characteristics. The controller coefficients are then included in VHDL (Very high speed integrated circuit Hardware Description Language) that implements the PID controller onto FPGA. MATLAB program is used to activate the PID controller, calculate and plot the time response of the control system. In addition, the hardware implementation uses VHDL and synthesis using FLEX10K Altera FPGA as target technology and use MAX+plusII program for overall development. Results in design are shown the speed performance and used area of FPGA. Finally, the experimental results can be shown when compared with the simulation results from MATLAB.