• Korean Journal of Environment and Ecology
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• v.23 no.1
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• pp.41-49
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• 2009

This research conducted a survey on the feeding crane's size, formation and distribution distance subsequent to road pattern and feeding flock's size during the wintering season eight times at the Cheolwon basin in Korea from December 2005 until February 2006. The survey results are as follows: First, the feeding flocks of the Red-crowned and White-naped Crane were found to mainly consist of two to four individuals. Mono-specific feeding flocks were more identified than hetero-specific feeding flocks in both Red-crowned and White-naped Cranes. There existed a significant difference in the ratio by size between the feeding Red-crowned and White-naped Cranes. The crane's average distribution distance from the paved road was much farther than from the unpaved road, paved farm road and unpaved farm road. In case of the white-naped crane, there was a difference in its distance length from between the road and farm road and there existed a significant difference only in the paved road in the distance length by road pattern between these two bird species[Red-crowned and White-naped Crane]. Such a result indicates that crane species don't prefer the road with frequent vehicular traffic to the road with low vehicular traffic. 5 or more individuals of feeding flocks of the Red-crowned Crane were located at a farther distance length from the paved road comparing to less than 5 individuals of the whole feeding flocks and less than 5 individual feeding flocks. 5 or more individuals of feeding flocks of the White-naped Crane were located at a farther distance length from the paved road, paved farm road and unpaved farm road than less than 5 individuals of feeding flocks of the White-naped Crane; however, there existed no difference in distance length subsequent to their group size. Conclusively, it was found out that the flocks with a larger size were more greatly affected by interrupting factors. Considering such results, there seems to be a more relation to the fact that larger size feeding flocks of crane species have a higher efficiency in the lookout for their surroundings.

• The Journal of Engineering Geology
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• v.19 no.2
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• pp.217-225
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• 2009

A series of model borehole experiments and analyses for density compensation were performed to achieve the effective density correction of gamma-gamma log obtained from PVC cased boreholes. A follow-up survey was made for clarifying the variation property of detector responses depending on casing types, the presence of borehole fluid, and the degree of separation between probe and borehole wall. A special emphasis was placed on the comparison of gamma responses obtained from above and below ground water tables. Finally, we could quantify the detector responses as a function of separation between the probe and borehole wall, construct standoff compensation charts, and the limitations of the compensation have been discussed for the environments of both above and below ground water tables.

• Journal of the Korean Geotechnical Society
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• v.15 no.1
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• pp.15-29
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• 1999

This study presents an analytical method of estimating the developed horizontal active thrusts against GRS-RW( Geosynthetic Reinforced Soil Retaining Wall) system adapted to the case of distanced surcharge. In addition, the design charts that could be used for preliminary design of GRS-RW system are presented. The proposed method of analysis uses two body translation mechanism as well as force polygon concept. taking into account the effect of facing's rigidity. Besides. the effect of tension cracks in c-\Phi$ soils, seismic effects and horizontal distance from the back face of wall to uniformly distributed surcharge loadings are also included. The results of horizontal active thrusts obtained from the developed method of analysis are compared with those from Jarquio's modified Boussinesq equation.

• Journal of Korean Society of Transportation
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• v.27 no.6
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• pp.89-96
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• 2009

The present study is performed to identify the relationship between apartment prices and distances from freeway interchanges. To collect consistent data and to simplify the sphere of the influence, the Seoul beltway was selected as the target road. Two sides of the Seoul beltway such as the inner side and the outer side are partitioned following the whole beltway line. The maximum distance to be taken care of in data collection was 6.0km from freeway interchanges. Results show that there exist consistent patterns between apartment prices and distances from freeway interchanges. In detail, if the apartment is located on the sphere of the influence, it is shown that a) the prices are increased overall b) the prices are low at very near of interchanges c) the prices are increasing up to the points of about 2.0~4.0km from interchanges d) the prices are decreasing after the points. Additionally, it is shown the pattern observed was following approximately a quadratic curve which is different from the liner curve obtained from the similar study over the sphere of the influence in railway(Subway).

• International Journal of Highway Engineering
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• v.11 no.1
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• pp.37-45
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• 2009

The minimum distance between tunnel and interchange has several steps to go through for road users; when road user comes out of tunnel, he/she reads information on road sign and tries to change the lane, and then reaches the destination (interchange). So that's why that minimum distance between tunnel and interchange has to be designed to reflect human factors sufficiently for road's users. This study aims to set for minimum distance between tunnel and interchange with involved human factors. People aged from their twenties to their seventies took part in this experiment by using driving simulator. As a result, the minimum distance between them was loom long. When it comes to this study for minimum distance between tunnel and interchange, this study will be significant in some ways reason why this method can be applied to all road facilities for road safety on scientific basis. In the near future, It will make a recommendation concerning the most suitable data for road safety by contributing better guideline.

• Journal of Korean Tunnelling and Underground Space Association
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• v.11 no.3
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• pp.255-264
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• 2009

This paper concerns the behavior of 2-Arch tunnel constructed under various conditions. A 2-Arch tunnel section adopted in a subway tunnel construction site is considered in this study. A calibrated 3D finite element model was adopted to conduct parametric studies on a variety of construction scenarios including lagged distance between left and right tunnels, overburden, and geological condition. The results of analyses were examined in terms of crown settlement, shotcrete lining stress, and load on center column in relation to the lagged distance, cover depth, and the ground condition. The results indicate that the shotcrete lining stress and the center pillar load are more influenced by the second tunnel excavation than the tunnel deformation. Also shown is that a greater lagged distance is required to minimize the interaction between two tunnels when the ground condition becomes weaker. Fundamental mechanisms of 2-arch tunnel were also discussed based on the results.

• Journal of Korean Tunnelling and Underground Space Association
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• v.4 no.2
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• pp.113-121
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• 2002

This study is focused on establishing influence zone caused by tunnelling in limestone site. Therefore, the numerical analysis using the FLAC2D was performed considering various locations and magnitudes of cavities. To reduce the stress concentration, the shape of cavities was designed to ellipse. This parametric study reveals that the cavities located at crown part and edge part of tunnel greatly have influenced on stability of tunnel. The effect of distance between tunnel and cavity which is larger than 1-0D (Tunnel diameter) dose not directly related to stability of tunnel, but the nearer a cavity location was, the larger displacement and stress of reinforcement occured within 0.25D.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.9
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• pp.847-851
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• 2016

Due to global warming it is estimated that the arctic ocean route will be avaliable and traffic will increase by approximately year 2030. However, most navigation in the arctic is based on the ice breaker captains'orders, there is no exact measurement of convoy speed and distance between ships. So, this research was conducted to find out the minimum safe separation distance and minimum breaking distance via ship controling simulations, and the results are as stated. For breaking distances, for ships that have a lead distance which is 2~4 times the width of the ship and traveling less than 7 knots, crash astern and crash astern & hard rudder showed no significant difference. But ships traveling at 10 knots there was a decrease in breaking distance of 1L, from 3.5L to 2.5L. By analyzing 10 subject ships by crash astern the breaking distance for 5 knots is 0.98L~1.8L, for 8 knots is 1.9L~4.0L. The minimum safe separation distance in narrow sea-ways is 6L, but as the arctic sea-way is only one-way 3L is required. As the result, it is found that in the arctic the safe escort speed is less than 5 knots, if the escort speed is 8knots or more and by using crash astern & hard rudder to break the safe distance should be kept at 3.4L.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2011.11a
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• pp.21-22
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• 2011

In this study, an analytical algorithm for collision avoidance is proposed, which is applicable to designing collision avoidance maneuvers for two encountering ships. The minimum separation distance is defined and an appropriate maneuver sequence is computed for safe and effective collision avoidance. Two approaches: 1) collision avoidance through speed change and 2) collision avoidance through heading change, are considered, and the initiation point of the avoidance maneuver is computed analytically using the geometric configuration of the two encountering ships. To verify the feasibility of the proposed algorithm, numerical simulations are carried out using a set of ship-to-ship encountering scenarios.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.9
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• pp.983-988
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• 2009

This paper analyzed the induced voltages on a telecommunication line due to high-speed a.c. electrified railway system. The induced voltages were measured by domestic regulation, 2 test lines with 2 km length were installed near railway in parallel to compare the influence for distance from disturbing line. The analysis was made on the induced voltages with the distance from railway, line length, and the different earthing point, and also on the waveform and spectrum distributions. The statistical induced voltages for the time for a day and dates was analyzed.