• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 2000년도 춘계공동학술대회 논문집
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• pp.160-163
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• 2000

Due to the complexities of the real-world system, a water resource management program has to deal with various types of data. It appears that management personnel who has to use the program usually suffers from the technical burdens of handling large amount of data and understanding the optimization theory when they try to interpret the results. By combining the capabilities of database technology and modeling technique with optimization procedure we can develop a reliable decision supporting tool for multi-reservoir operation planning, which yields operating schedule for each dam in a river basin. We introduce two special data handling methodology for the real world application. First, by treating dams, hydro-electric power generating facilities and demand sites as separate database tables, the proposed data handling scheme can be applied to general water resource system in Korea. Second, by assigning variable names using predetermined key words, we can save searching time for identifying the moaning of the variables, so that we can quickly save the results of the optimization run to the database.

• 한국정보통신학회논문지
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• 제6권4호
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• pp.589-594
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• 2002

Hairpin 형태의 필터는 크기를 작게 설계할 수 있지만 설계방법이 복잡하다는 단절이 있다. 본 논문에서는 기존의 전송선로 이론과 J 인버터 회로를 이용하여 Hairpin Line 필터 설계에 새롭게 적용하였으며, 설계하는데 필요한 J 와 b 파라미터를 정확히 구하는 방법을 제시하고 있다. 인접하는 소자간의 상호 결합이 없는 부분을 고려하였으며, 각 단에서의 결합성분에 대한 전기적인 결합선로 길이를 J 와 b 파라미터로부터 구할 수 있다. 제시하고 있는 설계방법으로 Serenade 8.0을 이용하여 중심 주파수 2.6GHz에서 동작하는 소형의 Hairpin Line 대역 통과 필터를 설계하고 컴퓨터 시뮬레이션을 통하여 특성을 확인하였다.

• Mycobiology
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• 제38권4호
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• pp.331-335
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• 2010

In this study, we developed an efficient electroporation-mediated transformation system featuring Flammulina velutipes. The flammutoxin (ftx) gene of F. velutipes was isolated by reverse transcription-PCR. pFTXHg plasmid was constructed using the partial ftx gene (410 bp) along with the hygromycin B phosphotransferase gene (hygB) downstream of the glyceraldehydes-3-phosphate dehydrogenase (gpd) promoter. The plasmid was transformed into protoplasts of monokaryotic strain 4019-20 of F. velutipes by electroporation. High transformation efficiency was obtained with an electric-pulse of 1.25 kV/cm by using 177 transformants/${\mu}g$ of DNA in $1{\times}10^7$ protoplasts. PCR and Southern blot hybridization indicated that a single copy of the plasmid DNA was inserted at different locations in the F. velutipes genome by non-homologous recombination. Therefore, this transformation system could be used as a useful tool for gene function analysis of F. velutipes.

• Journal of Chest Surgery
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• 제23권6호
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• pp.1107-1117
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• 1990

The regulatory role of the post \ulcorner1-and \ulcorner2-adrenoceptors on cardiac function, particularly in coronary flow rate, was investigated in the isolated rat heart treated with 10-6 M propranolol. When introduced into the left atrium of the heart, phenylephrine[10-7-10-2 M] decreased coronary flow rate and increased mean coronary resistance in a dose related fashion, but did not affect heart rate. Methoxamine also elicited the increment of coronary resistance and the decrement of coronary flow rate, though the effects of methoxamine were weaker than those by phenylephrine. The effect of phenylephrine was inhibited by 1\ulcornerM prazosin and shifting the dose-response curve to the right. The effects of clonidine, a selective \ulcorner2-adrenoceptor agonist, were studied in the heart taken from reserpinized rats. Clonidine increased coronary resistance, decreased heart rate and coronary flow rate with a dose-dependent manner. These effects were abolished by 10-6 M yohimbine, a selective \ulcorner2-antagonist, and were not affected by 10-6M prazosin. Clonidine also decreased coronary flow and increased mean coronary resistance in electric paced heart. These effects were inhibited by rawoulscine, a selective ca-antagonist. These results indicate that the stimulation of both post \ulcorner1-and \ulcorner2-adrenoceptor causes coronary vasoconstiction. And it is inferred that this model of sympathomimetics-induced coronary vasospasm may provide a useful tool for investigating spasmolytic agents which are of benefit in the treatment of variant angina.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 춘계 학술발표회
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• pp.607-614
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• 2010

Shear behavior of granular soils largely affects the safety and stability of underground and earth structures. This study presents the characteristics of shear zone in a direct shear test using shear wave and electrical resistivity measurements. An innovative direct shear box made of transparent acrylic material has been developed to prevent direct electric current. Bender elements and electrical resistivity probe are embedded in the wall of direct shear box to estimate the shear wave velocities and the electrical resistivity at the shear and non-shear zones. Experimental results show that the void ratio and shear wave velocity at shear zone increase during shearing while the values remain constant at non-shear zone. The results demonstrate correlation among the contact force, small strain shear modulus, and void ratio at shear zone. This study suggests that the application of the modified direct shear box including shear wave and electrical resistivity measurements may become an effective tool for analyzing soil behavior at shear zone.

• 음성과학
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• 제12권2호
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• pp.81-88
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• 2005

Electrodermal activity(EDA) is a bio-electric signal which occurs at the skin surface during the sweating. EDA reflects the activity of the sympathetic axis of the autonomic nervous system. EDA is associated with the eccrine sweat gland at the palmar and plamar surface. This study was aimed to characterize the relationship between EDA and auditory stimulus intensities. Acoustic stimulus used in this study were 500 Hz, 1 kHz, 2 kHz of narrow band noise, which were representative of speech frequencies in audible range. Stimulus intensity between 90 and 30 dB in 10 dB within dynamic range. After deriving the minimum stimulus intensity(threshold of skin potential) which elicited skin potential, and then the latency and amplitude were derived from waveform of skin potential, each latency and amplitude were compared to stimulus intensity. The waveform of skin potential were recorded stably, and the threshold of skin potential appeared nearly the hearing threshold level of the participant. The latency was decreased and the amplitude was increased according to the increase of the stimulus intensity. These results suggest that auditory evoked skin potential can be applicable to auditory assessment and audiological diagnosis tool.

• 대한전기학회논문지:전력기술부문A
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• 제53권11호
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• pp.610-618
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• 2004

With the development of industry and the improvement of living standards, better quality in power electric service is required more than ever before. Under these circumstances, to deliver reasonable voltage regulation methods in distribution systems need to be developed. So, This paper deals with optimal introduction of the line voltage regulator (SVR : Step Voltage Regulator) in power distribution systems. First, This paper investigates characteristics of SVR and performs economic evaluation of SVR's introduction by using Present Worth Method. This paper, also suggests proper location and optimal voltage regulation algorithm. In order to deliver suitable voltages to as many customers as possible, the optimal sending voltage of SVR should be decided by the effective operation of voltage regulators at the distribution feeders. The simulation results using a model distribution system and real distribution systems show that the proposed methods can be a practical tool for the voltage regulation in distribution systems.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 영호남학술대회 논문집
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• pp.327-330
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• 2000

The scanning Maxwell-stress microscopy (SMM) is a dynamic noncontact electric force microscopy that allows simultaneous access to the electrical properties of molecular system such as surface potential, surface charge, dielectric constant and conductivity along with the topography. The Scanning near-field optical / atomic force microscopy (SNOAM) is a new tool for surface imaging which was introduced as one application of the atomic force microscope (AFM). Operated with non-contact forces between the optical fiber and sample as well as equipped with the piezoscanners, the instrument reports on surface topology without damaging or modifying the surface for measuring of optical characteristic in the films. We report our recent results of its application to nanoscopic study of domain structures and electrical functionality in organic thin films by SMM. Furthermore, we have illustrated the SNOAM image in obtaining the merocyanine dye films as well as the optical image.

• ETRI Journal
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• 제34권4호
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• pp.527-535
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• 2012

A general equivalent circuit model is developed for a wireless energy transfer system composed of multiple coils via coupled magnetic resonances. To verify the developed model, four types of wireless energy transfer systems are fabricated, measured, and compared with simulation results. To model a system composed of n-coils, node equations are built in the form of an n-by-n matrix, and the equivalent circuit model is established using an electric design automation tool. Using the model, we can simulate systems with multiple coils, power sources, and loads. Moreover, coupling constants are extracted as a function of the distance between two coils, and we can predict the characteristics of a system having coils at an arbitrary location. We fabricate four types of systems with relay coils, two operating frequencies, two power sources, and the function of characteristic impedance conversion. We measure the characteristics of all systems and compare them with the simulation results. The flexibility of the developed model enables us to design and optimize a complicated system consisting of many coils.

• 한국공작기계학회논문집
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• 제16권1호
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• pp.75-79
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• 2007

The cathode design is one of the most important parts in order to enhance the performance of fuel cells. A 3-D model of the porous oxygen reducing cathode with perforated current collectors is analysed for the enhanced design in fuel cells. Simulation is performed using equations of electric potential balance, momentum balance, and mass balance. The gas concentrations are quite large and are significantly affected by the reactions that take place. The weight fraction of oxygen, velocity field for the gas phase, and local overvoltage are illustrated in the porous reactive cathode layer. The current density is also analysed and the result shows the distribution and variation are stated in a wide range. It is found that the rate of reaction and the current production is higher beneath the orifice, and decreases as the distance to the gas inlet increases. The significance of the results is discussed in the viewpoint of the mass transportation phenomena, which is inferred that the mass transport of reactants dictates the efficiency of the electrode in this design and at these conditions.