• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.6
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• pp.93-101
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• 2012

Bridge deck has a role in a comfortable and safe passage of vehicles. At the same time, it preserves upper structure against the abrasion and shearing due to impact of traffic loads in bridges or has a role to protect the plate from off adverse effect of climatic process as rain, chemicals. Currently, the total number of inspected bridges is 6,248 in the general national road and to maintain effectively, Introduction of GPR system mounted in the vehicle has been considered. In this research, the comparison and analysis of bridge deck condition on general national road has been performed with major variations of superstructure type, span lengths, located region and ages by using 'the current status of road bridge and tunnel' that is provided by MLTM(Ministry of Land, Transport and Maritime Affairs). As a result, Condition assessment grade, superstructure type, age and length were derived as a major factor to determine priority for the condition assessment.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.4
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• pp.13-18
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• 2016

Humidifiers are used to control indoor humidity. Element-type humidifiers have the advantages of simple structure and low energy consumption, and Japanese products have been widely used for the humidifying elements. In this study, a new humidifying element made of cellulose and PET was developed, and the performance was compared with that of a Japanese element. The mass transfer rates and pressure drops were measured for an element installed at the entrance of a suction-type wind tunnel. The humidification efficiency of the new element was 2 to 4% greater and the pressure drop was 23 to 32% smaller compared to the Japanese element. The mass transfer effectiveness ($j_m/f$) of the new element is also 5 to 28% higher. However, the water absorption capacity was smaller than that of the Japanese element, meaning further development is needed.

• Journal of Navigation and Port Research
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• v.36 no.5
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• pp.357-361
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• 2012

Anemometer is a meteorological instrument that measures wind direction and wind speed in real time, and is mounted to the cranes that are used at ports, shipbuilding yards, off-shore structure, or construction sites that are influenced by wind, and it is used in conjunction with the safety system. Load cell-type anemometer measures the wind direction through the ratio of load between 4 positions by mounting the thin plate to 4 load cells, and measures wind velocity through the summation of loads. In this study, we compared and analyzed the results in the theoretic approach, analytic approach and experimental approach to derive the correlation between load ratio and wind direction. Wind direction was selected as the design variable, and selected 9 wind direction conditions from $0^{\circ}{\sim}90^{\circ}$ with $11.25^{\circ}$ space for analysis, and 10 wind direction conditions with $10^{\circ}$ space for experiment.

• Journal of Korean Tunnelling and Underground Space Association
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• v.18 no.6
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• pp.511-524
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• 2016

Since a room-and-pillar underground structure is characterized by its grid-type array of room and pillar, its economical efficiency can be governed by excavation sequence. In this study, the construction period by the drill-and-blast method as a excavation method for a room-and-pillar underground structure was examined. In addition, the parallel excavation sequence was considered as the main sequence of a room-and-pillar underground structure. Sequences of mucking and support installation were derived to estimate the total excavation cycle by taking the case of a road tunnel into consideration. From the excavation cycle of room-and-pillar underground structure, the relationship between available maximum and minimum numbers of jumbo drill machines depending on the number of faces in operation was suggested.

• Journal of the Korean Institute of Landscape Architecture
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• v.36 no.3
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• pp.75-84
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• 2008

The purpose of this research is to find the visual characteristics and geographic structure in a landscape of mountains in Yangsan City. In order to carry out this study, 40 view points of 6 mountains in Yangsan City were selected to experience the mountainscape. The results are as follows. The mountainscape of Yangsan City was confirmed from the view point to the object of view as ranging in middle distance reverse, the angle of elevation 11${\sim}13^{\circ}$ which give the impression of confronted to the mountain, and the horizontal angle 50${\sim}90^{\circ}$ which gives the impression of vastness. This shows that mountainscapes are perceived impressively when seeing the mountain with the meaning to feel the texture of the mountain as a confrontational relationship rather than a pictorial relationship. The geographic structure of the view point which occurs in scenes of impressive experience is classified into eight types and its characteristics are investigated. The first type is corridor, and it emerges in a long narrow linear structure made from the surrounding environment with buildings or street trees. The second is tunnel in which a vision and light hidden while passing underneath a bridge, high-level road, or inside a tunnel can be seen. Third, the maze is formed by the mountain shape. The hill spur emerges when the direction of traffic changes after turning the coner of a building or mountain edge. The hill ground emerges at the top of a hill slope. Next, parallel emerges when the observer and the mountain are in the same direction of process. Confrontation occurs when confronting an isolated mountain. Finally, the view point emerges when passing through major points such as a bridge or square and the boundary of a village or city. This research arranged visual conditions that create impressive mountainscapes. Geographic characteristics in terms of Types that make possible to experience mountainscapes were described. The results of this research will be basic data collected for the management and preservation of mountainscapes and for landscape effect evaluation. Furthermore, this research suggests theoretical evidence to preserve and manage geographic structures that create view experiences as well as to preserve the landscape in terms of view points.

• Tunnel and Underground Space
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• v.30 no.5
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• pp.462-472
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• 2020

Rock classification is fundamental discipline of exploring geological and geotechnical features in a site, which, however, may not be easy works because of high diversity of rock shape and color according to its origin, geological history and so on. With the great success of convolutional neural networks (CNN) in many different image-based classification tasks, there has been increasing interest in taking advantage of CNN to classify geological material. In this study, a feasibility of the deep CNN is investigated for automatically and accurately identifying rock types, focusing on the condition of various shapes and colors even in the same rock type. It can be further developed to a mobile application for assisting geologist in classifying rocks in fieldwork. The structure of CNN model used in this study is based on a deep residual neural network (ResNet), which is an ultra-deep CNN using in object detection and classification. The proposed CNN was trained on 10 typical rock types with an overall accuracy of 84% on the test set. The result demonstrates that the proposed approach is not only able to classify rock type using images, but also represents an improvement as taking highly diverse rock image dataset as input.

• Journal of Cadastre & Land InformatiX
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• v.51 no.2
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• pp.5-20
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• 2021

With the available national spatial information that started from the sinkholes that occurred nationwide in 2014 and integrated 15 areas of underground information, the Underground Spatial Integrated Map has been continuously maintained since 2015. However, until recently, as disasters and accidents in underground spaces such as hot water pipes rupture, cable tunnel fires, and ground subsidence continue to occur, there is an increasing demand for quality improvement of underground information. Thus, this paper attempted to prepare a plan to improve the quality of the Underground Spatial Integrated Map data. In particular, among the 15 types of underground information managed through the Underground Spatial Integrated Map, quality validation improvement measures were proposed for underground facility (structure-type) data, which has the highest proportion of new constructions. To improve the current inspection methods that primarily rely on visual inspection, we elaborate on and subdivide the current quality inspection standards. Specifically, we present an approach for software-based automated inspection of databases, including graphics and attribute information, by adding three quality inspection items, namely, quality inspection methods, rules, and flow diagram, solvable error types, to the current four quality inspection items consisting of quality elements, sub-elements, detailed sub-elements, and quality inspection standards.

• Korean Journal of Environment and Ecology
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• v.25 no.5
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• pp.639-648
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• 2011

We recorded the movement of wildbirds nine times at Hoam 1st Tunnel, Kkachisan Park, Deungneung pass to compare the movement between eco-corridor and neighboring crossing road from June to September, 2006. Among three areas, birds did not prefer the eco-corridor at pass type such as Kkachisan Park and Deungneung pass, however number of species and individuals were high at the eco-corridor at Hoam 1st Tunnel. Over 90m width and the slope location of eco-corridors can be beneficial for wild birds to enhance the movement along eco-corridors between isolated two patches. Average foliage volume under two meters showed the relation with bush nesters, and that from 7 to 8m had the highest relationship with canopy nesters. In Seoul city, target species should be considered at the construction of eco-corridors according to site characteristics, but Paradoxornis webbianus could be suggested as a main target species at eco-corridors. To enhance the movement of diverse wildbirds, we would implement that eco-corridors could be located at the slope area with the size of 1ha (over 90m width), eco-corridors could be planted and managed with the high foliage volume of shrub layer under twometers and canopy layer over 8 meters.

• Journal of Korean Tunnelling and Underground Space Association
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• v.25 no.3
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• pp.201-220
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• 2023

Power cable tunnels is one of the underground structures meant for electricity transmission and are constructed using shield TBM method when transitting across urban and subsea regions. With the increasing shaft depth for tunnels excavation when the shield TBM excavated the rock mass, the review of selecting closed-type shield TBM in rocks becomes necessary. A simplified shield TBM design method is also necessary based on conventional geotechnical survey results. In this respect, design method and related design program are developed based on combined results of full-scale tests, considerable amount of accumulated TBM data, and numerical simulation results. In order to validate the program results, excavation data of a completed power cable tunnel project are utilized. Thrust force, torque, and power of shield TBM specification are validated using Kernel density concept which estimates the population data. The robustness of design expertise is established through this research which will help in stable provision of electricity supply.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.11
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• pp.2150-2158
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• 1992

This study was carried out to investigate the flow structure and mixing process of a cross mixing flow formed by two round jets with respect to the ratio of mass flow rate. This flow configuration is of great practical relevance in a variety of combustion systems, and the flow behaviour of a cross jet defends critically on the ratio of mass flow rate and the cross angle. The mass flow rate ratios of two different jets were controlled as 1.0, 0.8, 0.6, and 0.4, and the crossing angle of two round jets was fixed at 45 degree. The velocities issuing from jet nozzle with an exit diameter of 20mm were adjusted to 40m/s, 32m/s, 24m/s, and 16m/s, and the measurements have been conducted in the streamwise range of $1.1X_0$to $2.5X_0$ by an on-line measurement system consisted of a constant temperature type two channel hot-wire anemometry connected to a computer analyzing system. The original air flow was generated by a subsonic wind tunnel with reliable stabilities and uniform flows in the test section. For the analysis of the cross mixing flow structure in the downstream region after the cross point, the mean velocity profiles, the resultant velocity contours, and the three-dimensional profiles depending upon the mass flow rate ratio have been concentrately studied.