• 제어로봇시스템학회:학술대회논문집
• /
• 2000.10a
• /
• pp.485-485
• /
• 2000

A design method of model following control system using neural networks is proposed. An unknown nonlinear single-input single-output plant is identified using a multilayer neural networks. A linear controller is designed fer the linear approximation model obtained by linearinzing the identification model. The identification model is also used as a plant emulator to obtain the prediction error. Deficient servo performance due to controlling nonlinear plant with only linear controller is mended by adjusting the linear controller output using the prediction output and the parameters of the identification model. An optimal preview controller is adopted as the linear controller by reason of having good servo performance lowering the peak of control input. Validity of proposed method is illustrated through a numerical simulation.

• Plant Journal
• /
• v.6 no.2
• /
• pp.56-61
• /
• 2010

In this paper, an integrated management software is developed to promote the business competitive power. The interoperability among the software accounts for an ever growing performance of petrochemical plant project. If the interoperability is built up, company has taken advantages of quality, schedule, cost, and safety by active communication. The advantage of an integrated management software is examined in three aspects. In efficiency aspect, It takes advantage of the saving about the various information and the standard of project performance procedure. In quality, the integration gave aid to a quality improvement through team collaboration and data management within project life cycle. In cost, poor communications between systems waste 30% of project costs. If information could be inputted once and used by all, reductions in delivery time up to 40% were possible. Therefore, 10% savings of engineering cost was also possible.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2008.10a
• /
• pp.65-67
• /
• 2008

Kyoto Protocol against global warming came into effect in Feb 2005. This paper presents a calculation $CO_2$ emission of D power plant for combusting LNG and heavy oil using the a, b, c coefficients obtained by the performance test. The authors also calculate the breakeven point of the fuel transfer from LNG to Oil considering recent $CO_2$ emission cost.

• Proceedings of the KIEE Conference
• /
• 1995.07b
• /
• pp.695-698
• /
• 1995

The shape and width of fuzzy membership function has an effect on performance of fuzzy controller. In this paper, fuzzy controller is proposed to improve the control performance of fuzzy controller. It has two fuzzy inference engine. The one is typical fuzzy inference engine, the other is proposed to infer optimal width of membership function in fuzzy controller from plant constant (K,T,L). To show the effectiveness of this fuzzy controller with double fuzzy inference engine, it is applied to plant (dead time + 1st order delay) with various plant constant.

• Proceedings of the KIEE Conference
• /
• 1995.07b
• /
• pp.813-816
• /
• 1995

The shape and width of fuzzy membership function has an effect on performance of fuzzy controller. In this paper, neuro-fuzzy controller is proposed to improve the control performance of fuzzy controller. It has membership function, that is adapt to plant constant by using trained neural network. This neural network has been trained with back propagation algorithm. To show the effectiveness of proposed neuro-fuzzy controller with adaptive membership function, it is applied to plant (dead time + 1st order) with various plant constant.

• Journal of Power Electronics
• /
• v.2 no.2
• /
• pp.130-138
• /
• 2002

The windup phenomenon appears and degrades control performance when a controller with integrating action is used and plant input is limited. An anti-windup integal-proportional(IP) controller is proposed for the variable-speed moter drives and it is experimentally applied to the speed control of a vector-controlled induction moter driven by a pulse width modulated (PWM) voltage source inverter (VSI). The consistency range of the IP controller is firstly derived and the intergal state is controlled to salisfy always the consistency range according to whether the the controller output is saturated or not. Although the operating condition like moter load or speed command is changed under the limited plant input, It is expermentally verified that the speed response has much improved performance, such as no overshoot and fast settling time, and the maximmum plant input is also effectively utilized.

• Journal of Applied Biological Chemistry
• /
• v.64 no.2
• /
• pp.153-158
• /
• 2021

Cordyceps militaris (CM) is one of the most important medicinal mushrooms known to possess various biological activities. Cordycepin (CP) is a bioactive compound present in the fruiting bodies of CM and is known to have anti-tumor, anti-metastatic immunomodulatory and anti-inflammatory activities. In this study, we aim to analyze CP quantitatively under various CM extraction conditions. CP was measured using high-performance liquid chromatography, quantified using a reversed phase column using a gradient elution system of water and acetonitrile, and detected with a UV absorbance wavelength of 260 nm. The CP content of CM was the highest in 100% ethanol extract of the fruiting bodies and 60% ethanol extract of the mycelium. This study provides an efficient analysis method to determine the optimal extraction conditions for CP that can be used as a basis for developing functional foods and pharmaceutical products derived from CM.

• Journal of Applied Biological Chemistry
• /
• v.64 no.1
• /
• pp.63-67
• /
• 2021

Isovitexin, a marker compound with various pharmacological activities, in Lespedeza cuneata, was analyzed using high performance liquid chromatography coupled with UV (HPLC/UV). There are no previous reports on using L. cuneata as the source material for the quantification of isovitexin. In this study, we developed an optimized method using HPLC-UV analysis, which was validated using various parameters. Our method demonstrated high specificity, and good separation of the chromatographic peak was achieved. Parameters such as linearity (r2≥0.9997), precision, and accuracy indicated that our proposed analytical method had good reliability and sensitivity. These results demonstrate the utility and convenience of our method for rapidly quantifying isovitexin in L. cuneata extracts.

• Journal of Applied Biological Chemistry
• /
• v.64 no.1
• /
• pp.57-61
• /
• 2021

Saikosaponin derivatives such as saikosaponins A, B1, B2, B3, B4, C, and D present in Bupleurum falcatum were analyzed by a high performance liquid chromatograph equipped with an evaporative light scattering detector, using different extraction solvents (water and 70% ethanol). The samples were injected into a YMC Pack Pro C18 column and separated using a gradient elution system with a mobile phase composed of acetonitrile and water at a flow rate of 1.1 mL/min. The content of saikosaponin derivatives was higher in 70% ethanol extract than in water extract. This study provides an efficient analytical method for determining the optimal conditions for extraction of saikosaponin derivatives, which can be used as a basis for development of functional foods and pharmaceutical products from B. falcatum.

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 1993.10a
• /
• pp.363-372
• /
• 1993

For more accurate height/depth control of the agricultural implements , the soil surface as a reference position should be measured as accurate as possible. A new measurement system using microwave was developed to detect the true soil surface even under plant and/or vegetation. Two-frequency continuous-wave radar was used as the measurement system. It could estimate the distance to the target by measuring the phase difference between two different frequencies continuous-waves which reflected on the target surface. The system performance was evaluated on the barely field where the average height of barley was 91.5 cm. The experimental results showed that the system performance was not affected by the existence of barely. The maximum measurement errors were 8.91 com and 8.44cm for two different experimental plots.