• Korean Journal of Construction Engineering and Management
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• v.22 no.5
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• pp.29-38
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• 2021

Governments and companies are trying to reduce occupational accidents in the construction industry; however, the number of disasters are not decreasing significantly. This study aims to identify the correlation between factors affecting construction disasters quantitatively. To this end, 1,197 cases of serious disasters provided by Korea Occupational Safety and Health Administration (KOSHA) were analyzed using affinity analysis, one of the data mining techniques. The data from KOSHA were preprocessed and analyzed with variables of accident type, project type, activity type, original cause materials, sensory temperature, time of the accident, and fall height, and the association rules were derived for fall accidents and the others. For fall accidents, 64 association rules with lift ratios of 1.38 or greater were derived, and for the other accidents, 59 association rules with lift ratios of 1.54 or greater were derived. After analyzing the derived association rules focusing on the relationship among accident factors, this study presented the significance of applying the affinity analysis to address the study's limitations. The significance of this study can be found in that the correlation among factors affecting construction accidents is presented quantitatively.

• Journal of the Korean GEO-environmental Society
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• v.12 no.5
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• pp.13-19
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• 2011

The strength of granular mixtures can be controlled by the majority of the mixture, fine grains. However, in some cases, the small amount of gravel in the mixture may influence the strength of the mixture. In this study, the effect of some dispersed gravels on strength of sand is evaluated. Gravels are embedded in the middle of each cemented sand layer. The size and number of embedded gravels varies. After two days curing, a series of unconfined compression tests is performed on the cemented sand with dispersed gravels. In addition to that, a series of direct shear tests is also carried out on clean sand with gravels to evaluate its friction angle. For the specimens with the same ratio of gravel weight of 7% in which gravel size and number are different, an unconfined compressive strength(UCS) of a specimen with gravels decreases up to 15% compared to a specimen without gravel and then increases with increasing gravel number. For specimens embedded with the same size of gravel, UCS decreases and then increases as a number of gravel increases. As a number of gravel increases, a friction angle of clean sand with gravels decreases up to $5^{\circ}$ and then recovers up to that of a specimen without gravel.

• The Journal of the Korea Contents Association
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• v.21 no.6
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• pp.435-444
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• 2021

This paper discusses the geometrical interpretation of the Taegeuk Shapes of Kameun Temple through the geometric analysis of mathematics. Based on the literature, This paper attempted to clarify that the origin of Gameunsa's founding of the spirit of patriotism may coincide with historical records through historical literature and geometric meaning. First, the background of the founding of Kameun temple, geographical location located near the East Sea, especially the history of the ancient Chinese mathematics at the time, And that mathematical knowledge influenced all fields such as agriculture, architecture, and art. Secondly, it is related to the historical record as the space of about 60 centimeters, which is uniquely underground, was identified as the structure of the excavated space. It is thought that there is a strong correlation with the origin that the King Munmu changed into a dragon, and set up the temple to be able to stay. Based on these, the clues of the interpretation of the taegeuk and the triangular pattern were searched in the samcheon yanggi(參天兩地) of the Oriental and circumference of the Western. The taegeuk and triangular patterns represent the symbols of yin-yang harmony, which correspond to the origin of its creation. the Korean people regarded the mysterious dragon as a symbol of yinyang harmony. In conclusion the Shapes of Kameun temple's stone is consistent with the contents mentioned in the historical record.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.5
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• pp.111-118
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• 2020

The U-shaped composite beam used in this study consist of a reinforced concrete structure, a beam steel structure supporting the slab, a reinforced concrete structure, and a U-shaped steel plate. The U-shaped composite beam was developed for the purpose of using it as a parking lot because it is highly constructible and has low floor height and long span. For the improvement of constructivity, the U-shaped composite beam ends are planned with standardized H-shaped steel and connected directly to the columns, and the middle of the U-shaped composite beam consists of U-shaped steel plates folded in U-shaped form using thin steel plates (t=6) instead of H-shaped steel. In the middle of the composite beam, where U-shaped steel plates are located, the depth of U-shaped beam may be planned to be small so as to satisfy the height limit of the parking lot. It is important to grasp the structural performance according to the change of depth because low beam depth is advantageous for the reduction of the floor height, but it is a inhibitor to the structural behaviors of U-shaped composite beam. In addition, since U-shaped composite beams are a mixture of steel frame structures, reinforced concrete structures and U-shaped steel plates, securing unity has a great influence on securing structural performance. Therefore, in this study, a structural experiment was conducted to understand the structural performance according to the depth change for U-shaped composite beam. A total of three specimens were planned, including two specimens that changed the depth using a criteria specimen planned for a general parking lot. The results of the experiment showed that the specimens who planned the depth greatly had better structural performance such as yield strength, maximum strength, and energy than the standard specimen.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.3
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• pp.546-559
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• 2021

This research aimed to develop the district unit plan simulation using procedural modeling based on shape grammar. For this, Esri's CityEngine 2020.0 was selected as a main development tool, and Inside Commercial Area in Bangi-dong, Songpa-gu, Seoul as the research site where about 25% of the total area was developed over the past five years. Specifically, the research developed the simulation through the following three phases of Data-Information-Knowledge after selecting necessary parameters. In the Data phase, 2 and 3 dimensional data were obtained by utilizing data sharing platforms. In the next Information phase, the acquired data were generated into various procedural models according to the shape grammar, and the 2D and 3D layers were then integrated using relevant applications. In the final Knowledge phase, three-dimensional spatial analysis and storytelling contents were produced based on the integrated layer. As a result, the research suggests the following three implications for the simulation development. First, data accuracy and improvement of sharing platforms are needed in order to effectively carry out the simulation development. Second, the guidelines for district unit plans could be utilized and developed into shape grammar for procedural modeling. Third, procedural modeling is expected to be used as an alternative tool for communication and information delivery.

• Korean Journal of Construction Engineering and Management
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• v.23 no.1
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• pp.46-53
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• 2022

The railway platform is an important facility closely related to the safety of passengers, trains, and images of railway facilities, and requires thorough facility management. However, the problem that the finishing material (plastering mortar) for the joint finishing of dissimilar materials (concrete+granite) falls off in the direction of the track at the platform podium is occurring multiple times across the country. Since these problems threaten the safety of train operation and the safety of passengers, immediate and continuous management is required. This study tried to derive improvement plans through the analysis of the drop-off problem of finishing materials occurring at the platform podium. The status of missing finishing materials for the platform podiums of about 200 railway stations and the related design and construction standards of the Korea National Railway were investigated. After that, the cause of the drop-off of the finishing material was analyzed, and as a result, it was found that the main cause was the boundary between the roadbed and the architectural process that occurred during construction. Subsequently, in connection with the derived causes and design, construction standards, (1) improvement of finishing materials or construction methods, (2) design of finishing materials that are easy to adjust height, (3) design of separate finishing methods, (4) improvement methods and durability were suggested.

• Korean Journal of Construction Engineering and Management
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• v.23 no.4
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• pp.15-25
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• 2022

As the incidence and mortality of serious disasters in the construction industry are the highest, various efforts are being made in Korea to reduce them. Among them, risk assessment is used as data for disaster reduction measures and evaluation of risk factors at the construction stage. However, the existing risk assessment involves the subjectivity of the performer and is vulnerable to the domestic construction site. This study established a DB classification system for risk assessment with the aim of early identification and pre-removal of risks by quantitatively deriving risk factors using BIM in the risk assessment field and presents a methodology for risk assessment using BIM. Through this, prior removal of risks increases the safety of construction workers and reduces additional costs in the field of safety management. In addition, since it can be applied to new construction methods, it improves the understanding of project participants and becomes a tool for communication. This study proposes a framework for deriving quantitative risks based on BIM, and will be used as a base technology in the field of risk assessment using BIM in the future.

• Journal of the Institute of Convergence Signal Processing
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• v.23 no.4
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• pp.241-248
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• 2022

Shear Reinforcement of Dual Anchorage(SRD) is used to reinforce the safety of reinforced concrete structures at construction sites. Welding is used to make shear reinforcement, and welding plays an important role in determining productivity and competitiveness of products. Therefore, a weld bead detection inspection is required. In this paper, we suggest an algorithm for inspecting welding beads using image data of welding beads. First, the proposed algorithm calculates a brightness value in a vertical direction in an image, and then divides a welding bead in a vertical direction by finding a position corresponding to a 50% height point of the brightness value distribution in the image. The welding bead area is also divided in the same way for the horizontal direction, and then the segmentation image is analyzed if there is a welding bead. The proposed algorithm reduced the amount of computation by performing analysis after specifying the region of interest. In addition, accuracy could be improved by using all brightness values in the vertical and horizontal directions using the difference of brightness between the base metal and the welding bead region in the SRD image. The experiment compared the analysis results using five algorithms, such as K-mean and K-neighborhood, as a method to detect if there is a welding bead, and the experimental result proved that the proposed algorithm was the most accurate.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.2C
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• pp.109-117
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• 2010

Gas hydrate dissociation can generate large amounts of gas and water in gas hydrate bearing sediments, which may eventually escape from a soil skeleton and form voids within the sediments. The loss of fine particles between coarse particles or collapse of cementation due to water flow during heavy or continuous rainfall may form large voids within soil structure. In this study, the effect of void formation resulting from gas hydrate dissociation or loss of some particles within soil structure on the strength of soil is examined. Glass beads with uniform gradation were used to simulate a gas hydrate bearing or washable soil structure. Glass beads were mixed with 2% cement ratio and 7% water content and then compacted into a cylindrical sample with five equal layers. Empty capsules for medicine are used to mimic large voids, which are bigger than soil particle, and embedded into the middle of five equal layers. The number, direction, and length of capsules embedded into each layer vary. After two days curing, a series of unconfined compression tests is performed on the capsule-embedded cemented glass beads. Unconfined compressive strength of cemented glass beads with capsules depends on the volume, direction and length of capsules. The volume and cross section formed by voids are most important factors in strength. An unconfined compressive strength of a specimen with large voids decreases up to 35% of a specimen without void. The results of this study can be used to predict the strength degradation of gas hydrate bearing sediments in the long term after dissociation and loss of fine particles within soil structure.

• Journal of Environmental Impact Assessment
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• v.32 no.5
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• pp.338-352
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• 2023

As of 2019, Korea's fine dust is the most severe among 38 OECD countries, and in the same year, 「the Framework on Disaster and Safety Management」 was revised to define fine dust as a social disaster. Currently, the government is working to achieve its emission reduction goals by preparing a comprehensive fine dust management plan (2022-2023) consisting of a total of five areas, 42 tasks, and 177 detailed tasks. However, it is necessary to come up with measures in consideration of the various spatial characteristics of the city, not just as a source of emission. Therefore, in this study, the shape of the city was classified using the LCZ (Local Climate Zone) classification system into 17 types by building type and land cover type in Busan, and the average annual PM10 and PM2.5 concentration were mapped using the IDW technique. In addition, Fragstats and Moving Window were used to quantify the LCZ classification system. Finally, correlation analysis and regression analysis were conducted to analyze the relationship between the LCZ classification system and PM10 and PM2.5. As a result, it was confirmed that the type of low height of the building and the type of green space with trees had a positive effect on the concentration of PM10 and PM2.5. Therefore, this study is expected to be used as basic data to establish fine dust reduction policies based on efficient spatial planning.