• Ocean and Polar Research
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• v.28 no.4
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• pp.467-473
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• 2006

The EM 120, a newly installed multibeam echo sounder on RM Onnuri, has several advantages over the previously installed SeaBeam 2000 in performance and thus data quality. The EM 120 system provides a bottom topographic map with high resolution by (1) increasing the number of beams, (2) increasing the across track swath range, (3) measuring the more accurate sound velocity within the water column, and (4) improving stabilization for pitching, rolling, and yawing of the ship. This study compares EM 120 and SeaBeam 2000 echo sounders in terms of the data quality from the same survey area in the Clarion-Clipperton Zone, NE Pacific. Our result shows that the EM 120 provides more precise topographic data than the SeaBeam 2000. Although overall trends of data, such as topographic direction and relief, are similar for both echo sounders, the water depths measured by the EM 120 are shallower than that of SeaBeam 2000 by 80 to 90 meters.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.278-282
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• 2007

The riding comfort and the durability of train are effected by the rail irregularities such as track gauge, superelevation, alignment, longitudinal level, twist, cant and cross level. Inspection and estimation of irregularities are very important to maintain the rail condition. Generally, the EM120 has been utilized to measure the rail irregularities once a month in Korea. However, the EM120 can be operated at night time only, because the inspection speed of EM120 is much slower than the speed of high-speed trains. Also, the EM120 is too slow to inspect effectively for the whole commercial line. Therefore, we have mounted the track inspection system on the High-Speed Rolling Stock 350 eXperimental (HSR350X) and measured the rail irregularities to confirm the condition of a rail while running 300km/h. In this paper, the track inspection system mounted on HSR350X is mainly considered, and the measured results through test run are introduced.

• Proceedings of the KSR Conference
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• 2002.10a
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• pp.666-671
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• 2002

All work related to maintenance of track has been impletemented on the basis of the measured result from EM series cars in Korea. However, since these types of cars measure only versine value of the track irregularities instead of the real ones, this method will cause the confusion to maintenance operators if commercial speed should increase. This study was showing and explaining the program developed to get the real irregularities from the versine value. Finally, the reconstruction profiles completed by two different methods were compared with artificial track irregularities to confirm the their practicality.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.1264-1269
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• 2006

Measurement and estimation of rail irregularity is an important factor to concern travelling safety of train. Now a day, rail irregularity have been measured by EM120 and ROGER 1000K imported from MERMAC Co. Italy and making researches actively in Korea. This paper mainly consider to find correlation between acceleration value of wheel axle in HSR350x and rail irregularity value measured by EM120.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.25 no.4
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• pp.331-338
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• 2012

Irregularity data inspected by EM-120, an railway inspection system in Korea includes unavoidable incomplete and erratic information, so it is encountered lots of problem to analyse those data without appropriate pre-data-refining processes. In this research, for the efficient management and maintenance of railway system, characteristics and problems of the detected track irregularity data have been analyzed and efficient processing techniques were developed to solve the problems. The correlation between track irregularity and seasonal changes was conducted based on ARIMA model analysis. Finally, time series analysis was carried out by various forecasting model, such as regression, exponential smoothing and ARIMA model, to determine the appropriate optimal models for forecasting track irregularity progress.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.10a
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• pp.119-120
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• 2012

• Journal of Korean Society of Steel Construction
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• v.18 no.1
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• pp.47-51
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• 2006

Measuring the track geometry of a high-speed railway is the most important task in track construction and track maintenance work. Measuring accuracy is particularly sign the formulation of the maintenance plan and in the assessment of the work quality, and because it can set the train speed limit. To determine the track geometry of a high-speed railway, it is important to use KNR's track recording coach (EM-120). According to the result of the spectrum analysis, noise near the 1-m wave band was found on the track recording data. A new filter was thus applied to remove the noise from the track recording data. A similar result can be acquired when this method is used in real track geometry.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.28 no.4
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• pp.369-374
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• 2015

In this paper, an EM sensing based prestressing force estimation method is proposed, in which it can estimate tensile force of PS tendon for PSC girder. The PSC girder has more improved performance than the general concrete girder by introducing the prestressing to the concrete. Thus the PSC girder bridge is widely constructed due to its high performance and low cost. However, the prestressing force has not been managed nevertheless it is major factor for the maintenance of the PSC girder bridge. The prestressing force was just measured during construction using jacking device and after that, it can not be managed. For this reason, this paper proposes a tensile force estimation method of PS tendon based on EM sensor. The permeability of ferroelectric material is changed according to the induced stress to the material, in which it can be measured using EM sensor. To measure the permeability of PS tendon, the EM sensor was fabricated and verified by performing the MTS test. The test was performed using 7-wire steel tendon under the 0, 40, 80, 120, 160, 200 KN of tensile force. The permeability of PS tendon was gradually decreased according to the increasement of tensile force. The regression method was used to find the relation between permeability and stress. As a result, the permeability has linear relation with the tensile force of PS tendon and the pre-stressing force can be estimated by the derived estimation equation.

• Aerospace Engineering and Technology
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• v.8 no.2
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• pp.140-148
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• 2009

MOV(Main Oxidizer shut-off Valves) control the combustion of launch vehicle systems by the supply and the isolation of liquid oxygen to a main combustion chamber in launch vehicle systems. Moreover, in the steady operational state, the MOV should secure a constant flow rate of liquid oxygen for combustion instability in the combustion chamber. Concerning the development of MOV, TM(Technology Model) has been manufactured and normal operations of the valve have been verified. However, the Cv of TM has been proved to be too low as compared with a design specification value. Therefore, CFD analysis have been performed by modification of the configurations of TM in order to increase sufficiently Cv of EM(Engineering Model), which is the following model of TM. The modifications of TM configurations such as partial scale-up of valve, increase of stroke length, and outlet angle of 120o would result in a considerable augmentation of Cv. It has been verified by flow capacity tests that the improved Cv of EM is min. 212, which is higher than Cv of TM, 161 by about 32%.

• Journal of Food Hygiene and Safety
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• v.12 no.2
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• pp.141-152
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• 1997

This study was performed to investigate the toxic effect of pyrrolizidine alkaloids from symphytum officinale i n rat. For this experiment, 120 male and female rats of Sprague-Dawley strain were used. The experimental groups were divided into five: Group CM and CF served as normal control with its gender. Group EM1 and EF1 were fed a 1% Symphytum officinal extract diet for 8 weeks. Group EM2 and EF2 fed a diet containing 2% extract diet. 4% extract diet into group EM3 and EF3 and 8% extract diet into group EM4 and EF4 were given. The results were as follows: 1. The major alkaloids of Symphytum officinale extract were symphytine, echmidine, and lasiocarpine. The amounts of total alkaloid were 168 $\mu\textrm{g}$ PAs/$m\ell$ extract. And contents of Pas in leaves were 0.05% wt.. 2. Total serum bilirubin concentrations increased significantly in group EM2, EM3, and EM4. Group EF1, EF2, EF3, and EF4 showed statistical significance for the group CF (p<0.05). 3. Aspartate transaminase activities were increased significantly in group EM3 and EM4 (p<0.05). Aspartate transaminase activities of EF1, EF2, EF3, and EF4 showed statistical significance for the group CF (p<0.05). 4. Alanine transaminase activities increased significantly in group EM3, EM4 (p<0.05). Alanine transaminase activities of EF1, EF2, EF3, and EF4 showed statistical significance for the group CF (p<0.05). 5. Alkaline phosphatase activities increased significantly in group EM2, EM3, and EM4 (p<0.05). Alkaline phosphatase activities of EF1, FE@, EF3, and EF4 showed statistical sigmificance for the group CF (p<0.05). 6. istopathological analysis of liver specimens from group EM3 and EM4 showed focal necrosis, periportal necrosis and apoptpsis. Hepatocytes obtained from group EM2 showed fatty change and hydropic degeneration in group EM3 and EM4. Chromatolysis and chromatin margination was shown in group EF2 and EF3. With the above results, it was demonstrated that the Symphytum officinal extract could induce functional change of liver, and histopathological change of liver in rats fed a diet containing extract. In conclusion, because of the risk of intoxication or adverse effect, the composition, dosage and mode of administration of herbal products should be monitored strictly. And this study serves as a reminder that herbal as well as orthodox medications may have serious side effects.