• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.6 no.2
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• pp.19-27
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• 1988

In determining the horizontal positions, economic, speedy, and accurate analytical adjustment methods have studied and developed for a long time. From now on, the adjustment methods using both angles and distances are expected because the development of more precise instruments, E.D.M, and electronic total station provide us with more advantages than the conventional measurement system. The objective of this paper is to study the characteristics of triangulation, trilateration, and combination method due to change of the weight factor of angles, distances, azimuthes, and control point coordinates of combined geodetic network. The results of this study show that combined method is more accurate and effective than other methods in case of combined geodetic network as the other simple networks.

• Journal of the Korean Institute of Navigation
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• v.15 no.2
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• pp.87-96
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• 1991

The change of water level at Mokpo Harbour and its adjacent coastal area due to the construction of the Youngsan Estuary Barrage and the Third Land Reclamation Work of estuary barren had been roughly expected. Periodical floods, which occur 2 times per month, are also being observed at the low lying commercial areas near the Mokpo Old Harbor. Although it is said that the highest tidal current component among the tidal current records at the approaching channel to Mokpo Harbor is reduced to 6 kts, because of the esturary barrage, they do not give any precise statement or a deep analysis for the flooding and periodical water level change under certain environmental conditions. Moreover, they never tried the analysis of development plan considering the natural disaster such as typhoon or other extreme conditions. Thus, it is necessary to collect and analyze the data related to floodings, harbor oscillations, currents, and water quality , etc. because of the development considering the extreme condition. Thus, it is necessary to collect and analyze the data related to floodings, harbor oscillations, currents, and water quality, etc. because of the development considering the extreme condition and to evaluate the field observation and measurement, including the numerical model simulation based on the scientific approaches. This study deals the problem of the water level change among the integrated analyses of the coastal area changes. The result can be used for the integrated planning to give a strong foundation and it will contribute to the development of local area.

• Toxicological Research
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• v.19 no.3
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• pp.235-240
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• 2003

The modification of CYP2E1 activity is of considerable interest because of its role in the metabolic activation of a variety of toxic chemicals. In the present studies, the time-course of changes in human CYP2E1 activities was determined after treatment with ethanol, glycerol, 4-methylpyrazole or isoniazid using intact HepG2 cells transfected by human CYP2E1. Hydroxylation of chlorzoxazone was chosen for the measurement of CYP2E1 activity. CYP2E1 protein levels were increased upon cultivation of cells in the presence of ethanol, glycerol, 4-methylpyrazole or isoniazid for 24 hr. After 24 hr cultivation, ethanol or glycerol increased CYP2E1 activities, whereas 4-methylpyrazole or isoniazid inhibited. This different effect of the chemical inducers on CYP2E1 activi-ties persisted to subsequent 24 hr. Competitive inhibition study suggested that 4-methylpyrazole or isoniazid has stronger binding affinity to CYP2E1 than ethanol or glycerol. These results demonstrate that different binding affinity of the chemical inducers to the active site of CYP2E1 plays important role in determining real CYP2E1 activity in intact cells after treatment with the chemical inducers. Present study would be helpful in precise understanding of human CYP2E1-mediated toxicity.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.250-255
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• 2003

The position of a 3-dimensional(3D) point can be measured by using calibrated stereo camera. To obtain more accurate measurement ,more accurate camera calibration is required. There are many existing methods to calibrate camera. The simple linear methods are usually not accurate due to nonlinear lens distortion. The nonlinear methods are accurate more than linear method, but it increase computational cost and good initial guess is needed. The multi step methods need to know some camera parameters of used camera. Recent years, these explicit model based camera calibration work with the development of more precise camera models involving correction of lens distortion. But these explicit model based camera calibration have disadvantages. So implicit camera calibration methods have been derived. One of the popular implicit camera calibration method is to use neural network. In this paper, we propose implicit stereo camera calibration method for 3D reconstruction using support vector machine. SVM can learn the relationship between 3D coordinate and image coordinate, and it shows the robust property with the presence of noise and lens distortion, results of simulation are shown in section 4.

• Journal of the Korean Geosynthetics Society
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• v.18 no.4
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• pp.87-95
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• 2019

Earth-work calculation is the important data for estimating the optimal construction cost at the construction site. Earth-work calculations require the accurate terrain data and precise soil volume calculations. Drone surveying technology provides accurate topography in a short time and economic advantages. In this paper, a drone surveying technique was used to derive a high precision soil volume calculation system. Field demonstration were performed to verify the accuracy of the volume measurement system. The results of earth-work calculation using drone survey were compared with those of GPS surveying. In addition, the developed earth-work volume calculation algorithm is compared with the existing aerial survey software (Pix4D) to verify the accuracy.

• Biomaterials and Biomechanics in Bioengineering
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• v.1 no.1
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• pp.13-25
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• 2014

In the current study, a drug-eluting stent coated with biodegradable polymers and sirolimus was developed by using an ultrasonic nanocoater and characterized in aspects of surface smoothness and coating thickness. In addition, in vitro release profiles of sirolimus by changing top coating layer with different biodegradable polymers were investigated. Smooth surfaces with variable thickness could be fabricated by optimizing polymer concentration, flow rate, nozzle-tip distance, gas pressure, various solvents and ultrasonic power. Smooth surface could be generated by using volatile solvents (acetone, chloroform, and methylene chloride) or post-treating with solvent vapor. Coating thickness could be controlled by varying injection volume or polymer concentration, and higher concentration could reduce the coating time while obtaining the same thickness. The thickness measurement was the most effectively performed by a conventional cutting method among three different methods that were investigated in this study. Release profiles of sirolimus were effectively controlled by changing polymers for top layer. PLGA made the release rate 3 times faster than PDLLA and PLLA and all top layers prevented burst release at the initial phase of profiles. Our results will provide useful and informative knowledge for developing drug-eluting stents, especially coated with biodegradable polymers.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05a
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• pp.38-42
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• 2001

To observe the Langmuir films, displacement current measuring system(Nippon Laser & Electronics), $\pi-A$ isotherms measuring device, and Brewster Angle Microscope(BAM) were used. As results, for 8A5H, big tilt angle changes of many molecules were detected before liquid expanded phase when the monolayer was compressed and expanded by barrier. Also many small and bright points were detected by BAM when the displacement current radically changed. In $\pi$-A isotherms, surface pressure of 8A5H was radically decreased between 35 and 40[mN/m] and monolayer was assumed to be collapsed in solid condensed phase, since large bright domain was observed without change of displacement current and this bright boundary was not classified part of domain in BAM image. If we observe behaviors of molecules on the water surface in these three measurement at the same time, we can get more precise informations on L films and it could be good data for fabricating LB films.

• Journal of Welding and Joining
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• v.24 no.6
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• pp.13-20
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• 2006

Resistance spot welding is widely used for joining sheet metals in the automotive manufacturing process. Recently, servo-gun is used to increase the productivity and precise control the acting force. However, force control mechanisms have not been investigated with servo-guns until now. In this paper, it is proved that servo-motor current is proportional to torque and by experiment, experimental equation between servo-motor current and electrode force was derived. Algorithm for feedback control of electrode force was suggested using current measurement. In addition, applying soft touch method to this system the impact between electrode and specimen, which is the problem of air gun, could be reduced. Indentation made the force decrease in holding time of resistance spot welding. In order to overcome this problem, force compensation using the servo gun was used and it improved weld strength in good welding current range.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.559-563
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• 1996

Total 215 magnet power supplies are under operation in Pohang Light Source(PLS). Current, voltage and peak power handling capabilities of DC power supply are in the range of 21 to 643V, 45 to 850A and 0.94 to 531KW, respectively. The DC power supplies can be categoriezed as uni-polar and bipolar power. Typical required stability and ripple of uni-polar power supplies are ${\pm}0.005%$ and ${\pm}0.05%$, respectively. The bipolar power supplies should be maintained within ${\pm}0.05%$ stability and ${\pm}0.5%$ ripple. Precise measurement results show that all power supplies meet or exceed the required specifications. The long term operation reliability to be sufficient for a stable operation of the Pohang Light Source.

• Proceedings of the KIPE Conference
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• 2003.07a
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• pp.439-445
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• 2003

Since 1960s. container shipping volume has increased dramatically and continuous on a trend of rapid growth, and so the number of containers handled at the port increases. In order to improve yard crane operating efficiency, the precise position measurement of the yard crane is important. This paper describes the method to measure the absolute position of yard crane using the output pulse of an encoder and infrared sensors. The crane position is calculated by counting the output pulse of an incremental encoder, which is mounted on the wheel in the crane. By the way, the wheel slippage on rail may cause some errors in crane position information obtained from encoder pulses, and the errors in the crane position information are compensated with infrared sensors. The performance of proposed method is verified on experimental results with the simulator of yard crane, the size of which is about 1/10 with the real crane.