• The Journal of Engineering Geology
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• v.19 no.1
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• pp.1-8
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• 2009

Geophysical surveys were conducted on an upper part of a natural slope located at Daejeon University. Electrical resistivity and seismic refraction measurements were carried out to obtain information on a weathered zone and internal structure at shallow depth, while AMT measurement a bed rock and geological structure at deep depth. With all the techniques applied, these results show a good correlation between electrical resistivity images and refraction velocity distributions for the characterization of a weathering and geological structure at depth. In particular, AMT survey seems to be the powerful tool for detecting a distribution of a bed rock with deep depth. The combined geophysical investigation produced a detailed image of a subsurface structure and improved well in the interpretation.

• Journal of Navigation and Port Research
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• v.27 no.6
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• pp.639-643
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• 2003

The emphasis is put on the detailed knowledge on manoeuvring characteristic for the safe navigation while avoiding terrible collision between ships and on the guideline to the design and operation of the ship-waterway system The numerical simulation of manoeuvring motion was carried out parametrically for different ship types, ship-velocity ratios, separation and stagger between ships. As for the calculation parameters, the ratios of velocity difference (hereafter, $U_2$/$U_1$ ) between two ships were considered as 0.6, 1.2, 1.5. From the inspection of this investigation, it indicates the following result. Considering the interaction force only as parameter, the lateral distance between ships is necessarily required for the ship-velocity ratio of 1.2, compared to the cases of 0.6 and 1.5 regardless of the ship types. Furthermore, regardless of the ship-velocity ratio, an overtaking and overtaken vessel can be manoeuvred safely without deviating from the original course under the following conditions: the lateral distance between two vessels is approximately kept at 0.5 times of ship-length and 5 through 10. degrees of range in maximum rudder angle. The manoeuvring characteristic based on this investigation will be very useful for keeping the safety of navigation from the practical point of ships design and traffic control in restricted waterways.

• Proceedings of the KSRS Conference
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• v.1
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• pp.390-393
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• 2006

It is well known that synthetic aperture radar (SAR) provides information on ocean winds and surface waves. SAR data are of particularly high value in extreme weather conditions, as radar is able to penetrate the clouds providing information on different ocean surface processes. In this presentation some recent results on SAR observation of extreme wind and ocean wave conditions is summarised. Particular emphasize is put on the investigation of typhoons and extratropical cyclones in the North Pacific. The study is based on the use of ENVISAT ASAR wide swath images. Wide swath and scansar data are well suited for a detailed investigation of cyclones. Several examples like, e.g., typhoon Talim will be presented, demonstrating that these data provide valuable information on the two dimensional structure of the both the wind and the ocean wave field. Comparisons of the SAR observation with parametric and numerical model data will be discussed. Some limitations of standard imaging models like, e.g., CMOD5 for the use in extreme wind conditions are explained and modifications are proposed. Finally the study summarizes the capabilities of new high resolution TerraSAR-X mission to be launched in October 2006 with respect to the monitoring of extreme weather conditions. The mission will provide a spatialresolution up to 1m and has full polarimetric capabilities.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.3
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• pp.784-795
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• 1995

This paper represents the results of the experiments of the three-dimensional flow and the aerodynamic loss caused by the three-dimensional flow within the plane bucket blades. To research the secondary flow and the aerodynamic loss, the large-scale plane bucket blade of lst-stage in the low pressure steam turbine is made of FRP. The detailed investigation of the secondary flow and the aerodynamic loss using 5-hole pressure probe within turbine cascade has been carried out in the low speed wind tunnel. The limiting streamlines of the suction and endwall surface have been visualized by the oil film method. The flow visualization of the secondary flow has been performed by the laser light sheet technique and image processing system. By using the method mentioned above, it is possible to observe the evolution of the pitchwise mass-averaged flow deviation angle and total pressure loss coefficient, the secondary flow, and the aerodynamic loss through the cascade.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.274-278
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• 2002

Surface finishing is still indispensable for most rapid prototyping (RP) processes because of the inherent stair-stepped surface and shrinkage of the parts. These problems can be minimized in the $VLM-_ST$ Process, because it uses expandable polystyrene foam sheets, each of which has a thickness of3.9 mm and a linear-interpolated side slope. The use of thick layers, however, limits the process capability of constructing fine details. This study focuses on the design of post-processing tool for fine details of $VLM-_ST$ parts and investigation of thermal characteristics during EPS foam cutting using the post-processing tool. To calculate the heat flux from the tool into the foam sheet, the tool was modeled as a heat source of radiation for finite element analysis. Results of the analysis agreed well with those of the experiment.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.1161-1170
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• 2009

The Roads in Gangwon Province generally was made on purpose to use the military road. In case of these roads, tremendous dangerous cut slopes do exist and its road linear shape was badly designed. In order to make up for this situation, the government has continuously established the new road or performed the public works such as the straight line of the curved road. Soksil 2 cut slope was made through the road improvement work. This has small surface failures and collapses. In spite of dry season, this slope are leaking lots of groundwater at the unbelievable point. So as to get curious phenomenon right, we performed a detailed field investigation, the geomorphological analysis, the stability analysis considering field characteristic and ultimately proposed the countermeasure to make sure stability of Sokil 2 cut slope.

• 보존과학연구
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• s.15
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• pp.104-127
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• 1994

Traditional architecture has structural limits after some terms because it almost made by wood elements. So in the name of 'Restoration', by anatural process, repair works are accomplished. But the repair works of traditional buildings have some problems in spite of best men power and technology. To overcome this problems, we need more detailed studies for examine the reasons of destruction in elements of wooden buildings. The life limits of wooden buildings are caused by natural circumstances and humanic circumstances, the former has bad effect on the damage in wooden buildings. There are various elements of damage in the wooden buildings, earthquake, the falling of a thunderbolt, fire, and rain, microorganism, insect, and so on. Moreover pollutions-sulfurous acid gas, acidorganic matters -are important reason of shortening the life of wooden buildings. From 1981 till now we investigated important traditional buildings under repair works by the way scientific analysis to catch the sample - seramics, woods, insects, metals, etc. In this reports we suggest various method of investigation with two samples of tradional house made by wood, one is Kim Joo Tea House, the order is Simgum-dang of Magok-Sa(dwelling of monk).

• East Asian mathematical journal
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• v.36 no.2
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• pp.229-251
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• 2020

Problem Based learning(PBL) is a teaching and learning method to increase mathematical ability and help achieving mathematical concepts and principles through problem solving using the learner's mathematical prerequisite knowledge. In addition, the recent instructional situations or environments have focused on the learner's self construction of his learning and its process. In spite of such a quite attention, it is not easy to apply and execute PBL program actually in class. Especially, there are some difficulties in actually applying and practicing PBL in the areas of mathematics education in not only secondary school but also in college. Its reason is that in order to conduct PBL instruction constantly in real or experimental class there is no more concrete and detailed instructional content during the consistent and long period. However, to whom is related to mathematics education including instructors called scaffolders, investigation and recognition on the degree of the learner's acquisition of mathematical thinking skills and strategies is an very important work. By the reason, in this study, the instructional content was to be explored and developed to be conducted during 15 weeks in one semester, which was based on Problem Based Learning environment by the subject of the theories relevant to mathematics education in the college of education.

• Journal of Korean Society for Geospatial Information Science
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• v.14 no.1 s.35
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• pp.75-83
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• 2006

Satellite imagery is generally used for investigating the damage from natural disaster for wide area and remotely piloted vehicle or aerial photos are used for the local damage. But for more detailed information such as damages of public facilities, these methods are inadequate and so in this case field surveying has been carried out. We tried to estimate the damage of public facilities faster and more accurately using photogrammetric method. We developed a digital stereo camera system by fixing two digital cameras on a frame, and with this system the photos of actually damaged areas were collected. The damages were estimated from these stereo photos. Then the estimated data was compared with field surveying data in order to verify our system.

• Journal of the Korean Electrochemical Society
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• v.5 no.4
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• pp.221-225
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• 2002

Assisted by the highly sensitive confocal microprobe Raman spectrometer and proper surface roughening procedure, the Raman investigation on the adsorption and reaction of methanol was performed on Pt-Ru electrodes with different coverages. A detailed description of the roughening process of the Pt electrodes and the underpotential deposition of the Ru was given. Reasonably good Raman signal reflecting the metal-carbon vibration and CO vibration was detected. The appearance of vibrations of the Ru oxides, together with the existence of Ru-C, Pt-C and CO bands, clearly demonstrates the participation of the bi-functional mechanism during the oxidation process of methanol on Pt-Ru electrodes. The Pt-Ru electrode was found to have a higher catalytic activity over Pt electrodes. This preliminary study shows that electrochemical Raman spectroscopy can be applied to the study of rough electrode surface.