• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.8
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• pp.287-297
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• 2020

This study examined ways of improving the internal insulation performance of aging university buildings, and to enhance the convenience of occupants in university buildings and the insulation effect of aging buildings. This research was conducted to solve the problem of continuous requests for improving the insulation performance of office workers in the Nehemiah Hall building of Handong University. The results showed that the internal temperature of Nehemiah Hall was low compared to the internal temperature of the adjacent building. Considering the characteristics of the building, the university chose insulating materials under the theme of internal insulation. The experiment was conducted by installing internal wall insulation used in the market by producing a model room that miniaturized the university professor's office. Based on the experimental results, an economic evaluation was conducted to analyze the insulation effect by measuring the heating time and actual heat transmission coefficient. An economic evaluation was conducted by experiment and theory and on a winter and summer basis. According to the research, when an Isopink (30 T) was introduced as an internal insulation material in 60 offices of Nehemiah Hall, it could save up to 1,071,600 won in total during the winter season and 109,200 won during the summer season.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.34 no.6
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• pp.619-627
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• 2016

Cells of a PV (photovoltaic) module can suffer defects due to various causes resulting in a loss of power output. As a malfunctioning cell has a higher temperature than adjacent normal cells, it can be easily detected with a thermal infrared sensor. A conventional method of PV cell inspection is to use a hand-held infrared sensor for visual inspection. The main disadvantages of this method, when applied to a large-scale PV power plant, are that it is time-consuming and costly. This paper presents an algorithm for automatically detecting defective PV panels using images captured with a thermal imaging camera from an UAV (unmanned aerial vehicle). The proposed algorithm uses statistical analysis of thermal intensity (surface temperature) characteristics of each PV module to verify the mean intensity and standard deviation of each panel as parameters for fault diagnosis. One of the characteristics of thermal infrared imaging is that the larger the distance between sensor and target, the lower the measured temperature of the object. Consequently, a global detection rule using the mean intensity of all panels in the fault detection algorithm is not applicable. Therefore, a local detection rule was applied to automatically detect defective panels using the mean intensity and standard deviation range of each panel by array. The performance of the proposed algorithm was tested on three sample images; this verified a detection accuracy of defective panels of 97% or higher. In addition, as the proposed algorithm can adjust the range of threshold values for judging malfunction at the array level, the local detection rule is considered better suited for highly sensitive fault detection compared to a global detection rule. In this study, we used a panel area extraction method that we previously developed; fault detection accuracy would be improved if panel area extraction from images was more precise. Furthermore, the proposed algorithm contributes to the development of a maintenance and repair system for large-scale PV power plants, in combination with a geo-referencing algorithm for accurate determination of panel locations using sensor-based orientation parameters and photogrammetry from ground control points.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.37 no.3
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• pp.83-92
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• 2019

This study aims to examine at the garden characteristics of salt merchant in Yangzhou, China during the Ming and Qing Dynasties, I looked at the background of garden formation through the literature. In addition, analyzed the garden design method and components of salt merchants. The results were as follows; First, the Yangzhou area in the past has achieved cultural and economic development with the establishment of the ancient Grand Canal. Salt merchants accumulated wealth through trade, and created many gardens under the background of securing materials for create garden through trade, forming political forces through the cultivation of students, and inflow of foreign cultures. Second, salt merchants in Yangzhou asked garden experts to design and create the garden as a place for exchange and relaxation. Also, through the production of landscape changes using Gasan(假山) and a long corridor(長廊), clear classification of spaces using architectural elements, and the placement of buildings in scenic areas adjacent to the water, the gardens with practical and aesthetic functions were owned. Third, the gardens of Yangzhou Salt Merchants have a building-oriented commercial space on the front, and a garden-centered design characteristic on the back. The garden of the commercial zone was built in a simple form using pots, oddly shaped stone, bamboo and fence patterns in the remained space, focusing on the front of the building. The garden at the back formed a curved waterway connected to the canal is refracted across the garden. The garden also features piled stones(疊石), stone bridges and ship-shaped stone building(石舫). In addition, the design reflected the introduction of trees that take into account the climate and color contrast of Yangzhou province, pavement of various materials and patterns.

• Journal of the Korean Institute of Gas
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• v.24 no.4
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• pp.18-24
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• 2020

The purpose of this study is to validate thermal hinderance effects, i.e., feasibilities, of fire-proof structure for LPG tank exposed to fire from adjacent burning building. The panel materials suggested for the fire-proof structure are (1) 10 mm-thick wood, (2) wood with fireproof coating, (3) 75 mm-thick Expanded Polystyrene, (4) 75 mm-thick glass wool filled sandwich panel, and (5) 75 mm-thick autoclaved lightweight concrete. The square planar fire source of 1 ㎡, a matrix of nozzles releasing 120-140 g/s of LPG, is used to heat up the wall and the tank beyond, mimicking heat transfer from burning exterior wall finishes. The feasibility is tested by inspecting structural integrity after test, and then by examining temperatures at both sides of panels and tank's front surface as well as heat fluxes. As a result, it can be concluded that, among the suggested sample materials, fire-proof wall with ALC panel only showed the feasibility for explosion prevention with the proven evidences of structural integrity and least increase in temperature of tank.

• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.6
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• pp.629-636
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• 2022

Domestic eco-friendly vehicles currently account for 5.8% of the total registered vehicles in Korea. Hydrogen vehicles, one of the representative eco-friendly vehicles, have grown rapidly as they have been expanded to the market based on the government's policy to boost the hydrogen industry. Therefore, it is time to expand the safety review of hydrogen vehicles in various directions according to the increase in supply. In this study, the effect of internal heat damage was analyzed when a jet flame was generated by a hydrogen car in a road tunnel. It was simulated using Fluent, and the amount of jet flame injection was selected in consideration of the hydrogen tank capacity of commercial hydrogen vehicles for road tunnels. In addition, the study was conducted with the direction of the jet flame and the nozzle distance from the tunnel wall as variables. From the results, when the jet flame erupted in the road tunnel, high radiant heat emission of more than 20 kW/m² was generated in most areas within ±5 m in the longitudinal direction based on the vehicle (spray nozzle) and 5 to 7 m in the lateral direction based on the adjacent tunnel wall.

• Journal of the Korean Geotechnical Society
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• v.38 no.11
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• pp.55-67
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• 2022

This study applied the dynamic cone penetrometer test (DCPT) and light-weight deflectometer test (LWDT) to the quality control of subgrade base by performing DCPT, LWDT, and plate load test (PLT) at two earthwork sites. Although DCPT and LWDT were performed under the same conditions, the results showed significant variation with the test location. Because the measured value at the time of the initial blow, which varies depending on the test location, significantly influenced the test result. Thus, it was appropriate to ignore the first two blows as preliminary blows and use subsequent measurements as quality control indicators. In addition, DCPT, LWDT, and PLT results showed a high correlation under the same conditions. Especially regression analyses using averaged data for each experiment condition tended to yield significantly improved R² values over individual point data sets. This indicates that average DCPT and LWDT values at various adjacent locations are better quality control indicators for subgrade bases than individual point values.

• Journal of the Korean Geotechnical Society
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• v.37 no.11
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• pp.37-49
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• 2021

Micropiles are widely used in construction field to enhance bearing capacity and reduce settlement of existing foundation. It has various benefits such as low construction expense, simple installation process, and small construction equipment. Recently, new microple equipped with the base expansion structure at the end has been developed to improve the foundation bearing capacity. The improvement of load capacity can be conceptually achieved by expanding the base expansion structure when a load is applied to the micropile. However, the expansion mechanism of the base expansion structure and the improvement of load capacity of the micropile were not yet experimentally validated. Therefore, in this study, a series of centrifuge model tests was performed to evaluate the effect of the base expansion structure on the improvement of load capacity. Two types of soil, sand and weathered rock, were prepared and the loading tests were performed using the real micropile with the base expansion structure. During the tests, the earth pressures surrounding the base expansion structure were monitored. As a result, when a load of 30 kN was applied to the micropile, the increase in the ratio of the horizontal to vertical pressure increment (∆σ_h/∆σ_𝜈) ranged from 0.4 to 0.58 in sand and ∆σ_h/∆σ_𝜈 = 0.19 in weathered rock, respectively. Therefore, it can be concluded that the increase in the horizontal earth pressure adjacent to the base expansion structure will improve the bearing capacity of the micropile.

• The KIPS Transactions:PartA
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• v.12A no.6 s.96
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• pp.515-522
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• 2005

This paper presents a method for effectively modeling inlay/onlay prostheses restoring a tooth that are partially destroyed. An inlay/onlay is composed of internal surface adhering to an abutment, and external surface revealed to the outside sight. Internal surfaces are modeled using Minkowski sum expanding the grinded surface parts of abutments so that the internal surfaces can adhere to the abutments with closer contact. In modeling external surfaces, we exploit 3D mesh deformation techniques: DMFFD(direct manipulation free-form deformation)[19] and MWD(multiple wires deformation)[17] with three kinds of informations: standard teeth models, mesh data obtained by scanning a plaster cast of a patient's tooth, FGP(functionally guided plane) measuring the occlusion of the patients's teeth. The standard teeth models are used for building up the basic shapes of external surfaces, while the plaster fast and FGP data are used for reflecting the unique properties of adjacent md occlusal surfaces of the patients's teeth, which are slightly different to each other but very important for correct functioning. With these informations as input data, the adjacent and occlusal surfaces are automatically generated as mesh data using the techniques of DMFFD and m, respectively. Our method was implemented so that inlay/onlay prostheses fan be designed more accurately by visualizing the generated mesh models with requirements by dentists.

• Explosives and Blasting
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• v.24 no.2
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• pp.83-91
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• 2006

Over the past few decades, blasting vibration has been mainly analysed to understand characteristics of far field vibration in the area comparatively far from blast hole in the respect of proving limit of building damage. However, over the last few years, many works have been carried out to estimate damage within the rock adjacent to a blast hole, especially for the Purpose of over break in tunnel blasting and rock slope stability There are several methods to estimate rock damage, but method of using blast vibration has been mostly used to estimate rock damage. Formerly, to estimate rock damage, method of expecting near field vibration using the characteristics of far field vibration had mainly used but nowadays, it is practically possible to measure near field vibration according to development of monitoring system. A few repels relating to this have been studied aboard, but very little work has been conducted in our country because of difficulty of monitoring and choice of monitoring system. Accordingly, in this Paper, measurements of near field vibration were conducted and wave forms were analyzed and some problems were investigated in measuring system.

• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.2
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• pp.129-151
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• 2022

In the current work, a series of three-dimensional finite element analyses have been carried out to understand the behaviour of piles when the adjacent tunnelling passes underneath grouped piles with a reinforced pile cap. In the current study, the numerical analysis studied the computed results regarding the ground reinforcement condition between the tunnel and pile foundation. In addition, several key issues, such as the pile settlements, the axial pile forces, the shear stresses and the relative displacements have been thoroughly analysed, and the IoT platform based preliminary design guidelines were also presented. The pile head settlements of the nearest pile from the tunnel without the ground reinforcement increased by about 70% compared to the farthest pile from the tunnel with the maximum level of reinforcement. The quality management factor data of the piles were provided as API (Application Programming Interface) of various forms by the collection and refinement. Hence it has been shown that it would be important to provide the appropriate API by defining the each of data flow process when the data were created. The behaviour of the grouped piles with the pile cap, depending on the amount of ground reinforcement, has been extensively analysed, and the IoT platform regarding the quality management of piles has been suggested.