• The Transactions of the Korean Institute of Electrical Engineers D
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• v.52 no.8
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• pp.506-509
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• 2003

This paper describes the possibility of analyzing gait pattern from the changes of the lower leg electrical impedance. This impedance was measured by the four-electrode method. Two current electrodes were applied to the thigh, knee, and foot., and two potential electrodes were applied to the lateral, medial, and posterior position of human leg. The correlation coefficients of the joint angle and the impedance change from human leg movement was obtained using a electrogoniometer and 4ch impedance measurement system developed in this study. We found the optimal electrode position for knee and ankle joint movements based on high correlation coefficient, least interference, and maximum magnitude of impedance change. The correlation coefficients of the ankle, knee, and the hip movements were -0.913, 0.984 and 0.823, respectively. From such features of the human leg impedance, it has been made clear that different movement patterns exhibit different impedance patterns and impedance level. This system showed feasibility that lower leg movement could be easily measured by impedance measurement system with a few skin-electrodes.

• Proceedings of the IEEK Conference
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• 2003.07c
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• pp.2887-2890
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• 2003

This paper describes the possibility of analyzing gait pattern from the variation of the lower leg electrical impedance. This impedance is measured by the four-electrode method. Two current electrodes are applied to the thigh, knee, and foot, and two potential electrodes are applied to the lateral, medial, and posterior position of lower leg. The correlation coefficients of the joint angle and the impedance change from human leg movement was obtained using electrogoniometer and 4ch impedance measurement system developed in this study. We found the optimal electrode position for ankle, knee and hipjoint movements based on high correlation coefficient, least interference, and maximum magnitude of impedance change. The correlation coefficients of the ankle, knee, and the hip movements -0.87, 0.957 and 0.80. respectively. From such features of the lower leg impedance, it has been made clear that different movement patterns exhibit different impedance patterns and impedance level. This system showed possibility that lower leg movement could be easily measured by impedance measurement system with a few skin-electrodes.

• Journal of Welding and Joining
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• v.11 no.2
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• pp.27-41
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• 1993

The estimation of nugget sizes was attempted by utilizing the artificial neural networks method. Artificial neural networks is a highly simplified model of the biological nervous system. Artificial neural networks is composed of a large number of elemental processors connected like biological neurons. Although the elemental processors have only simple computation functions, because they are connected massively, they can describe any complex functional relationship between an input-output pair in an autonomous manner. The electrode head movement signal, which is a good indicator of corresponding nugget size was determined by measuring the each test specimen. The sampled electrode movement data and the corresponding nugget sizes were fed into the artificial neural networks as input-output pairs to train the networks. In the training phase for the networks, the artificial neural networks constructs a fuctional relationship between the input-output pairs autonomusly by adjusting the set of weights. In the production(estimation) phase when new inputs are sampled and presented, the artificial neural networks produces appropriate outputs(the estimates of the nugget size) based upon the transfer characteristics learned during the training mode. Experimental verification of the proposed estimation method using artificial neural networks was done by actual destructive testing of welds. The predicted result by the artifficial neural networks were found to be in a good agreement with the actual nugget size. The results are quite promising in that the real-time estimation of the invisible nugget size can be achieved by analyzing the process variable without any conventional destructive testing of welds.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.737-738
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• 2002

To develop and improve a GIS(Gas Insulated Switchgear), the prediction of the pressure in puffer cylinder and the flow between the nozzle and the moving electrode within GIS is very important.The leading companies in GIS business issue the results of the study of flow within GIS including arc plasma. In this study, the characteristics of the flow of the GIS developed by HHI(Hyundai Heavy Industries Co. Ltd.) was investigated. To simulate the compressible flow of GIS, the CFX, a commercial CFD code, was used. With moving grid method, the movement of piston and electrode was simulated. The moving grid method was superior to the method of varying the property of cells to move an obsticle, in stability and convergencce of solution. The calculated maximum pressure within the puffer cylinder was matched with experimental data within $5{\%}$ error. The oscilation of pressure in GIS after the movement of electrode was well predicted.

• Proceedings of the KIEE Conference
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• 2002.11c
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• pp.414-417
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• 2002

This paper describes the possibility of analyzing gait pattern from the variation of the lower leg electrical impedance. This impedance is measured by the four-electrode method. Two current electrodes are applied to the thigh and foot., and two potential electrodes are applied to the lateral aspect, medial aspect, and posterior position of lower leg. We found the optimal electrode position for knee and ankle joint movements based on high correlation coefficient, least interference, and maximum magnitude of impedance change. From such features of the lower leg impedance, it has been made clear that different movement patterns exhibit different impedance patterns and impedance level.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.4
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• pp.318-323
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• 2004

When a strong electric field is applied between a sharply curved electrode and a blunt surface, the corona may result in a gas movement in the electrode gap which is directed toward the blunt surface. That is called the corona wind. It enhances heat and mass transfer between the surface and the surrounding gas. Moreover such enhancement causes no noise or vibration, which can be applied in complex, isolated geometries, and allows simple control of surface temperatures. This paper examines the relationship between the corona wind and the relative humidity. The facility consists of high voltage power supply thin tungsten wire, plate electrode, multimeter, microammeter and flow meter. Gas velocity is a linear function of voltage, relative humidity and is proportional to the square root of the current. The maximum velocities for the positive and negative corona discharge are 1.9 m/s (2.74 CMM/m), 1.5 m/s(2.15 CMM/m), respectively.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.199-201
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• 2006

A lot of researches and experiments have been performed to make more efficient dye-sensitized solar cell. Among them, insertion of a grid electrode in DSC is one method to increase overall performance as being shortened distance of electrons' movement by diffusion. In this paper, we measured overall characteristics which is included voltage-current characteristic curve, efficiency, fill factor by comparison between DSC without and with grid electrode. As a result, we got maximum 1.8 times increase of efficiency and approximately 1.7 times rise of fill factor. And we experimented 8, 10, 12, 14mm of grid gap and compared their results to optimize grid gap which is able to incite the most effective movement of electrons. Consequently, we got the result that electrons' movement is the most effect ive when grid gap is approximately 12mm.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.799-801
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• 2002

To develop GIS (Gas Insulated Switchgear), prediction of the flow field including pressure in GIS is very important. The transport phenomena in GIS including arc is also being studied in these days. In this study, to predict the arc behaviour for GIS with voltage rating up to 800kV developed by HHI (Hyundai Heavy Industries Co. Ltd.), the analysis of flow and electric field in GIS were investigated. To simulate the compressible flow in GIS, the CFX, commercial CFD code, was used. The movement of the piston and the electrode of the GIS was simulated with moving grid method, which was superior to the method of varying the property of cells in the aspect of accuracy and convergence of solution. The calculated maximum pressure within the puffer cylinder was matched with experimental data within 5% error. Also, the oscillation of pressure in GIS after the movement of electrode was well predicted.

• Proceedings of the IEEK Conference
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• 2003.07c
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• pp.2891-2894
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• 2003

This paper describes the possibility of analyzing gait pattern from the variation of the lower leg electrical impedance. This impedance is measured by the four-electrode method. Two current electrodes are applied to the thigh and foot., and two potential electrodes are applied to the lateral aspect. medial aspect, and posterior position of lower leg. We found the optimal electrode position for knee and ankle joint movements based on high correlation coefficient, least Interference, and maximum magnitude of impedance change. From such features of the lower leg impedance, it has been made clear that different movement patterns exhibit different impedance patterns and impedance level.

• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.940-942
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• 2003

This paper describes the possibility of analyzing gait pattern from the variation of the lower leg electrical impedance. This impedance is measured by the four-electrode method. Two current electrodes are applied to the thigh and foot, and two potential electrodes are applied to the lateral aspect, medial aspect, and posterior position of lower leg. We found the optimal electrode position for knee and ankle joint movements based on high correlation coefficient, least interference, and maximum magnitude of impedance change. From such features of the lower leg impedance, it has been made clear that different movement patterns exhibit different impedance patterns and impedance level.