• Korean Journal of Food Science and Technology
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• v.29 no.2
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• pp.273-278
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• 1997

In order to investigate the punch properties of some vegetables-cucumber, radish, garlic, ginger and potato-force, distance, and time were measured with a texturometer, and the correlations between compositions and cell characteristics of samples were characterized. Many reflection and rupture points on the force-distance and distance-time curve were observed, and these points appeared when the cells of sample were resisted and yielded against the applied force. They were big and clear at the slow crosshead speed. The regression analysis for force-time and distance-time to the rupture point showed $R^{2}>0.95$. The rupture time and rupure force were 5.63 sec, 4.88 N in ginger and 4.15 sec, 2.00 N in cucumber. The rupture forces become large values at the fast crosshead speed. As cell sizes were increased, the moisture content and rupture distance were increased, while the viscosity of juice, density, regularity of cell, and slope of force-time were decreased. Rupture force, time and distance were decreased at the large specific gravity of samples. The slopes of distance-time curve were inversely proportional to slope of force-time curve.

• The KIPS Transactions:PartB
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• v.14B no.2
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• pp.81-88
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• 2007

We implement automobile license plates recognition system. These days automobile license plate recognition systems are widely used for tracing stolen cars. managing parking facilities, ticketing speeding cars, and so on. Recognition systems largely consist of three parts plates extraction, segments extraction, and segment recognition. For plates extraction, we measure the degree of inclination of plate. We use filters that extract only the horizontal components of the front of an automobile to measure the degree of inclination. For segment extraction, we trace the change of the number of blocks that consist solely of foreground pixels or background pixels as the horizontal scanning line moves along upward. For recognition of each individual letter or digit, we devise a variant of template matching method, called comparative template matching. Through experiments, we show that comparative template matching is less prone misled by noises and exhibits higher performance compared to the traditional method of template matching or histogram based recognition.

• Applied Chemistry for Engineering
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• v.10 no.2
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• pp.206-211
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• 1999

Mixed-bed ion exchange performance was studied experimentally with variations of cation to anion resin ratio, resin weight and temperature at ultralow sodium chloride solution concentrations of less than $1.0{\times}10^{-4}M$. Analyzing the effluent concentration histories the performance test was examined as a function of tested solution volume for a laboratory-scale continuous flow column until both the cation and anion-exchange resins were exhausted. Initial leakage was observed for both cation and anion breakthrough curves, but serious at cation breakthrough curve because of low selectivity coefficient. The slope of breakthrough curve was affected by selectivity coefficient and temperature. The slope of anion breakthrough curve was steep because of the large selectivity coefficient, and ion exchange rates increased as temperature increased. The temperature effect decreased as the total volume was increased or as the resins were exhausted.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.11
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• pp.1148-1153
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• 2006

Signal measuring system to analyze ion concentrations in biofilm was constructed with ion selective microeleclrode and electrometer. In order to evaluate the performance and applicability of signal measuring system, the following characteristics, such as slope of calibration curve, detection limit, variation of response according to the time, and potentiometric selectivity coefficient, were investigated. The slope of calibration curve showed high degree of association for primary ion concentration. The response of the system was log-linear in standard solution down to $10{\mu}M$ and signal measuring system was not sensitive for interfering ions. In comparison with commercial electrometer, the fabricated electrometer system had similar tendencies for the slope of calibration curve, detection limit, and response time. Therefore the signal measuring system could be used to investigate ion profiles in biofilm as a cost effective and reliable measuring system.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.12
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• pp.1251-1256
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• 2015

This study investigates the friction noise characteristic in relation to the corrosion of metal by using the frictional reciprocating and pin-on-disk system. From the experiments, it is found that the corrosion of metal advances the onset time and increases the magnitude of friction noise. Further, it is observed that the effect of corrosion on friction noise stems from the alteration of tribo-surface during repetitive frictional motion. The alteration of the corrosive contact surface induces a negative friction-velocity slope, by which the corrosion of metal can generate dynamic instability faster than non-corrosion of metal.

• Journal of the Korean Chemical Society
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• v.46 no.1
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• pp.19-25
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• 2002

We measured the variations of potentials and current densities for several polymers. The results were carefully examined to identify various factors such as temperature and pH to influence the potential and rate. The Tafel slope for anodic dissolution was determined by the polarization effect under these conditions. The optimum conditions were established for each case. The second anodic current density peak and maximum current density were designated as the relative polarization sensitivity $(I_r/I_f)$. The mass-transfer coefficient value $({\alpha})$ was determined by the Tafel slope for anodic dissolution on the basis of the polarization effect under optimum conditions.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.8 no.1
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• pp.187-192
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• 1998

Generally the solidified microstructures of materials consist of the columnar and equiaxed dendritic regions, and many theoretical studies about columnar-to-equiaxed transition have been done because that is closely related to the mechanical and physical properties of products. In this study, the modified equation based on the Hunt's analytical columnar-to-equiaxed transition condition which was derived from heterogeneous nucleation and grain growth in front of the columnar dendrite tip under directional solidification, was obtained applying the growth-velocity-dependent distribution coefficient and liquidus slope to Hunt's. The effects of the number of nucleation sites, nucleation temperature, alloy composition, growth velocity and liquid temperature gradient on the transition for Al-Cu alloys have been investigated.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.9
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• pp.1925-1931
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• 2011

This paper suggests an approach to the subtle concept, "good", through the fuzzy logic and the design of the Canny edge detector of Gray scale images based on the rules of fuzzy anisotropic diffusion. The Canny edge detection algorithms design is to divide the gray levels into pixels and then calculate the diffusion coefficients at each pixel of non-edgy regions. Based on this processing, we present the Canny edge detector implementing fuzzy logic and comparing the results to other existing methods. The proposed approach is the narrow dynamic range of the gray-level image Sharpening the edge detection and has the advantage.

• The Transactions of the Korean Institute of Power Electronics
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• v.5 no.2
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• pp.131-139
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• 2000

일반적으로 시스템 인식과 제어에 이용하는 다층 신경회로망은 기존의 역전파 알고리즘을 이용한다. 그러나 결선강도에 대한 오차의 기울기를 구하는 방법이기 때문에 국부적 최소점에 빠지기 쉽고, 수렴속도가 매우 늦으며 초기 결선강도 값들이나 학습계수에 민감하게 반응한다. 이와 같은 단점을 개선하기 위하여 확장된 칼만 필터링 기법을 역전파 알고리즘에 결합하였으나 계산상의 복잡성 때문에 망의 크기가 증가하면 실제 적용할 수 없다. 최근 신경회로망을 선형과 비선형 구간으로 구분하고 칼만 필터링 기법을 도입하여 수렴속도를 빠르게 하고 초기 결선강도 값에 크게 영향을 받지 않도록 개선하였으나, 여전히 은닉층의 선형 오차값을 역전파 알고리즘에 의해서 계산하기 때문에 학습계수에 민감하다는 단점이 있다. 본 논문에서는 위에서 언급한 기존의 신경회로망 알고리즘의 문제점을 개선하기 위하여 은닉층의 목표값을 최적기법에 의하여 직접계산하고 각각의 결선강도 값은 반복최소 자승법으로 온라인 학습하는 알고리즘을 제안하고 이들 신경회로망 알고리즘과 비교하고자 한다. 여러 가지 시뮬레이션과 실험을 통하여 제안된 방법이 초기 결선강도에 크게 영향을 받지 않으며, 기존의 학습계수 선정에 따른 문제점을 해결함으로써 신경회로망 모델에 기초한 실시간 제어기 설계에 응용할 수 있도록 하였다. 또한, 유도전동기의 속도추정과 제어에 적용하여 좋은 결과를 보였다.

• Journal of the Korean Society of Propulsion Engineers
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• v.11 no.5
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• pp.14-22
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• 2007

A reversed trapezoidal fin with variable lateral surface slope is optimized using a two-dimensional analytic method. For a fin base boundary condition, convection from the inside fluid to the inside wall and conduction from the inside wall to the fin base are considered. Heat loss from the fin tip surface is not ignored. The maximum heat loss at the practical fin length, the corresponding optimum fin efficiency, fin length and fin base height are presented as a function of the fin inside and outside convection characteristic numbers. One of the results shows that the optimum fin shape becomes 'fatter and shorter' as the ratio of fin tip height to base height increases.