• The Transactions of the Korean Institute of Power Electronics
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• v.6 no.3
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• pp.273-281
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• 2001

In this paper, we propose a CMAC(Cerebellar Model Articulation Controller) neural network for controlling a non-linear system. CMAC is a neural network that models the human cerebellum. CMAC uses a table look-up method to resolve the complex non-linear system instead of numerical calculation method. It is very fast learn compared with other neural networks. It does not need a calculation time to generate control signals. The simulation results show that the proposed CMAC controllers for a simple non-linear function and a DC Motor speed control reduce tracking errors and improve the stability of its learning controllers. The validity of the proposed CMAC controller is also proved by the real-time tension control.

• Journal of ILASS-Korea
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• v.6 no.4
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• pp.22-30
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• 2001

The objective of this study is to develop the new equations for the calculation of higher heating values(HHVs) of reformed diesel fuels by ultrasonic treatment. Therefore, higher heating values of reformed diesel fuels by ultrasonic treatment are determined experimentally and calculated from their viscosity and surface tension measurements. The HHVs of the fuels are supposed to be a function of viscosity(Pa s) and surface tension(N/cm). The equations developed for the samples represent the correlation obtained by means of regression analysis. The HHVs calculated by developing new equations using viscosities showes the differences from the measured values ranging from -0.66 to 1.19 % and the correlation coefficient was -0.9411. The HHVs calculated by developing new equations using surface tensions showed the differences from the measured values ranging from -0.70 to 1.51 % and the correlation coefficient was 0.9999. The viscosity and the surface tension are characteristic properties of ultrasonic reformed diesel fuels for developing new formulae.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.228-231
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• 2001

Construction of roof structure, cable suspended structure, for Pusan main stadium is adapted a lifting method that is VSL lifting system. 5 precesses are practiced for erection of the roof structure including the first lifting process for erection of upper cables and the second lifting process for erection of lower cables. Since all cables of this roof structure with two open speller sockets are determined their length, some cable were wrong length, the roof structure would be unstable. But At complete of erection for the roof structure each cab3e is attained to theoretical tension force with average $4\%$ errors.

• Aerospace Engineering and Technology
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• v.4 no.1
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• pp.31-38
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• 2005

Conceptual design of an Aerostat was completed. Configuration was determined based on wind tunnel test results of aeostat hulls to have longitudinal static stability. Hull surface area and volume were obtained by using of Cubic spline method for given configuration and length. Final length of a hull was determined by iteration process. Cable tension and payload were estimated for conceptual design. A parametric study was performed for various weight and misson altitude. As results, a 30m class aerostat was designed and described.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1991.04a
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• pp.41-45
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• 1991

구조 진동에 의해 발생하는 Relative Sound Power를 계산하는 문제가 최근 에 중요시되고 있다. 이 논문에서는 조화적인 집중하중에 대한 무한 탄성보 에서 방출하는 Relative Sound Power를 연구한다. Sound Power는 수치적으 로 적분되고 몇가지 인자들의 함수로써 적분인자를 표시하였다. Keitie와 Peng[2]는 진동하는 보로부터의 방출하는 Relative Sound Power에 대한 하 중 길이의 효과, 그리고 water 하중을 받는 보에서 방출하는 Acoustic radiation에 대한 Source 운동과 기초 강성의 효과를 연구하였다. 보의 진동 응답에서 light fluid loading과 heavy fluid loading에 의한 양쪽의 반응을 고 려한다. 보에는 기초 강성과 Damping 그리고 장력이 작용한다. water 하중 과 air 하중을 받는 보에서 Damping의 변화에 대한 보로부터 방출하는 relative sound power의 크기를 결정하였다. 일반적으로 인장력보다 압축력 이 작용할 때 relative sound power level이 크다는 것을 알고 있다. 실제로 인장력이나 압축력이 보에 작용할 때 relative sound power에 얼마나 영향을 미치는가를 계산하였다. 그리고 진동계로부터 방출하는 sound fluid loading 과 기초 강성에 기인한 복잡한 효과를 해석하였다. 이 논문의 목적은 강성계 수와 wavenumber 비, 그리고 fluid loading에 대한 sound power의 응답에 대하여 설명하고자 한다.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.23 no.3
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• pp.127-130
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• 1987

The Cavitation inception in oil hydraulic pipeline was investigated experimentally and numerically. In the experiment, negative pressures below -1 MPa (absolute pressure) were measured, associated with the transient flows in oil hydraulic pipeline. These experimental results show that the common hydraulic oil in the experimental pipeline withstands large tensions. The growth of a spherical bubble in a infinite volume of viscous compressible fluid due to a stepwise pressure drop was investigated to obtain the critical bubble radius. The calculated value of the critical bubble radius corresponding to the negative pressure measured in the experiment is so small that the premised condition about the bubble shape in the analysis is unsatisfactory. The physical significance of this calculated result implies the fact that there hardly exist free bubbles which can act as cavitation nuclei in the experimental pipeline.

• Korean Journal of Soil Science and Fertilizer
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• v.17 no.1
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• pp.7-11
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• 1984

A study was carried out to develop a modified Gardner's method, which enabled us to obtain simultaneously both the unsaturated hydraulic conductivities and the moisture retention curves by the use of a soil moisture pressure-plate extractor. The unsaturated hydraulic conductivity was calculated from soil moisture changes under different tension ranges in the pressure- plate extractor by means of Gardner's pressure-plate outflow equation. From 30mbar-tension to 10bar-tension, the unsaturated hydraulic conductivities obtained on three soils (Bonryang sandy loam, Yesan silt loam, and Pogog clay loam) varied $3.09{\times}10^{-2}cm/day{\sim}4.06{\times}10^{-6}cm/day$, $1.34{\times}10^{-2}cm/day{\sim}7.30{\times}10^{-6}cm/day$, and $1.83{\times}10^{-2}cm/day{\sim}8.50{\times}10^{-6}cm/day$, respectively. In comparison with the outflow method, it is inconvenient to perform the periodic determinations of the soil moisture content that require release of the applied Pressure before readjusting the pressure desired for each measurement. Nevertheless, the main advantage of the modified method is that the unsaturated hydraulic conductivities of different soils can be calculated simultaneously with a small amount of each soil sample. It is concluded that the unsaturated hydraulic conductivity can be calculated from soil moisture changes in the soil moisture pressure-plate extractor.

• Applied Chemistry for Engineering
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• v.5 no.3
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• pp.457-465
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• 1994

Interfacial tension between liquid soil and aqueous solution of surfactant can be obtained from theoretical and/or experimental data. A correlation factor(r) between work(Wac) from theotical interfacial tension and detergency was 0.93 at lower concentration(0.04%) and 0.37 at higher concentration(0.1%) but a correlation factor(r) from experimental data(Wae) was 0.95 and 0.84, respectively. There were, therefore, good correlation between adhesional work and detergency at lower concentration but large deviation between them from theoretical and experimental one at higher concentration.

• Fire Science and Engineering
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• v.18 no.3
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• pp.9-17
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• 2004

The values of physical properties of the inert gases of Ar, $N_2$, $CO_2$ were calculated by the empirical equations. The regression coefficients were obtained by the experimental data and the resulting calculated values. For the empirical equation with a lower regression coefficient, a new correlation was suggested. At an atmosphere pressure, the empirical equation was confirmed by the experimental values for the viscosity, density, saturated pressure, and surface tension of Ar, $N_2$, $CO_2$. The correlation coefficients of the empirical equations proposed in this work was higher than 0.99.

• Composites Research
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• v.31 no.6
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• pp.385-391
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• 2018

In this study, carbon fibers were fabricated via carbonization of oxidized polyacrylonitrile (oxi-PAN) under different carbonization conditions. Carbonization of oxi-PAN fiber was performed under four different temperature (1300, 1400, 1500, $1600^{\circ}C$) with four different fiber tensions (14, 25, 35, 45 MPa). Effect of carbonization process on the structural development and mechanical properties of carbon fiber were characterized by single filament fiber tensile test and Raman spectroscopy. A clear correlation exists between the Raman spectrum and the tensile modulus of carbon fiber and effect of carbonization temperature on the tensile modulus showed increased tendency only at higher fiber tension (${\geq}25MPa$) while tensile strength showed decreased or random tendency. Therefore, it may be concluded that the optimization of carbonization temperature of oxi-PAN fiber also requires optimization of fiber tension.