• Journal of the Korea Institute of Building Construction
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• v.22 no.4
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• pp.379-390
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• 2022

While the construction industry is striving to make changes suitable for the 4th industrial revolution era through the introduction of 4th industrial revolution technologies, such change is progressing more slowly than in other industries. Nevertheless, the recent digitization and digital transformation of the construction industry can provide a new paradigm to address and innovate the chronic problems faced by the construction industry. Therefore, in this study, a case study using a data hub and API for use of the data hub, which is essential for digitalization and digital transformation, was conducted, and the efficiency and feasibility of using the data hub and API were considered. When the API system was introduced, it was found that the average budget savings per person was about 23%, and the costbenefit ratio was about 4.4 times higher, indicating that the feasibility of the project was very high. The results and framework of this study can serve as fundamental research data for related research, and provide a worthy case study to promote the introduction of related technologies. This will ultimately contribute to digitalization and digital transformation for smartization of the construction industry.

• Journal of Wetlands Research
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• v.25 no.2
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• pp.83-90
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• 2023

Due to climate change, the occurrence of abnormal rainfall is increasing, and the intensity and scale of damage caused by heavy rain are increasing every year. In addition, as the frequency of heavy rains becomes more frequent, heavy rains often occur continuously, resulting in large flooding damage that has never been seen before in urban area. When near rivers and coastal areas are impermeable areas, the maximum flow increases rapidly as the rainfall intensity increases, so a comprehensive flood risk evaluation is needed considering the characteristics of the basin. In this study, the flood inundation risk evaluation was analyzed by giving scores on evaluation factors as a measure to prevent inundation in subway stations. Through the flood inundation risk evaluation process considering the comprehensive evaluation index, the flood risk evaluation was conducted on five urban railway stations with a large amount of traffic and floating population that had been inundated in the past. It is judged that by comprehensively analyzing this and establishing a inundation risk grade (grade 1 to 4) to establish a flood measure suitable for the risk grade.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.3
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• pp.353-362
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• 2023

In this research, the usage status and characteristics of user big data of Mobike, a dockless bike sharing service introduced in Suwon city, were analyzed, and multiple regression analysis was performed to identify factors influencing the demand for dockless bike sharing service. For analysis, usage data of bike sharing system in Suwon city in 2019 were obtained, and they were organized by areas. As a result of analyzing the characteristics of the influencing factors selected for each area, it was found that the extension of bicycle roads shows high in areas with high demand for bicycles or adjacent areas. Also, the population of 10-30's shows high in areas with high demand for bicycles or adjacent areas. In addition, it was analyzed that the use of bike sharing system is high in areas with high maintenance rate of bicycle roads and large-scale residential and commercial facilities near residential districts and adjacent areas. As a result of the multiple regression analysis, it is analyzed that length of bicycle·pedestrian roads (non-separated), population of 10-30's, number of railway stations, number of schools, number of commercial facilities, number of industrial facilities factors were significant. It is expected that it may be possible to create an environment in which citizens want to use dockless bike sharing service by identifying factors affecting the number of stationless shared bicycles. Also, the results of data analysis are considered to be contributing to policy data to promote the use of dockless bike sharing.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.4D
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• pp.679-686
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• 2006

Recently, the city railway in the Seoul Metropolitan Area (SMA) has offered a low quality of service as a passage time, because it was operated slowly. So, the people who live in modern society are not satisfied about passage time, therefore, this study tried to make that the subway in the SMA becomes a more functional and effective wide-area-transportation-network through an express train introduction's method which examined cases from abroad and current system. and then presented how express train could be applied to current system. In a case study, We used the An-San Line and Su-In Line as a examples and developed a schedule which can minimize the delaying time of subway by using Branch & Bound Algorithm. The train operational plan was loaded to consider a railroad siding, Obtained site, and the dispatch interval(three to ten minutes) for the express and local lines and finally, We presented an alternative operational plan which made by those factors.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.4D
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• pp.671-678
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• 2006

In this study, to describe vehicle-structure dynamic interaction phenomena with 1/4 vehicle model, nonlinear Hertzian contact spring and nonlinear contact damper are adopted. The external loads acting on 1/4 vehicle model are selfweight of vehicle and geometry information of running surface. The constraint equation on contact surface is implemented by the Penalty method with stabilization and the reaction from constraint violation. To describe pitching motion of various vehicles two types of the displacement constraint equations are exerted to connect between car bodies and between bogie frames, i.e., the rigid body connection and the rigid body connection with pin, respectively. For the time integration of dynamic equations of vehicles and structure Newmark time integration scheme is adopted. To reduce the error caused by inadequate time step size, adaptive time-stepping technique is also adopted. Thus, it is expected that more versatile dynamic interaction phenomena can be described by this approach and it can be applied to various railway dynamic problems with low computational cost.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.6D
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• pp.839-847
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• 2008

No proper system exists for private investment projects, and efficient project management is not being achieved due to entanglements of management. Recognizing these circumstances, this paper has diagnosed the hard facts that project management organizations and systems are facing, and presented solutions to the factors that are obstructing the establishment of efficient project management system. This paper carried out focus group interviews on the experts who had participated in the Incheon International Airport Railway construction project, using the methodology of an exploratory case study. The results were systematically analyzed according to organizational behavior and causes corresponding to each of the problems were deduced. Private investment projects were divided into task environments and project organizations based on social science methodology and analyzed, and a final improvement plan for each participating organization was presented. An improvement plan was presented, and it was compared with the case study of Incheon bridge construction project, which is recognized as a model of successful project management, and its appropriateness evaluated.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1D
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• pp.95-103
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• 2006

One of the main functions of the 4D system includes visualizing numerical schedule data in construction. The existing 4D tools have an excellent function for simulating building projects that all activities are progressed according to vertical work zone. However, it is not easy to implement all of it in the civil engineering project because the construction activities of highway and railway projects are progressed on the horizontal work zone and the 4D simulation for those projects should include earthwork objects that depend on the natural ground condition. This study suggests a new methodology for improving those limitations of 4D system for the civil engineering project and develops a new system by the suggested methodology. To verify the developed system, this study attempts to simulate 4D object for horizontal elements such as earthwork, paving work and tunneling work. The morphing and multi-texturing techniques developed in the study can be new approaches to simulate 4D object for the earthwork such as cutting and banking whose activities are progressed on the natural ground condition. The research results can be expected as a draft function for improving the application of 4D system in civil engineering projects.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.2D
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• pp.299-309
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• 2006

Railway noise and vibration has been recognized as major problems with the speed-up of rolling stock. As a kind of solution to these problems, the decrease of stiffness of track pad have been tried. However, in this case, overturning of rail due to lateral force should be considered because it can have effect on the safety of running train. Therefore, above two things - decrease of stiffness of track pad and overturning of rail due to lateral force - should be considered simultaneously for the appropriate determination of spring coefficient of track pad. With this viewpoint, minimum spring coefficient of track pad is estimated through the comparison between the theoretical relationship about the overturning of rail and 3-dimensional FE analysis result. Two kinds of Lateral force and wheel load are used as input loads. Extracted values from the conventional estimation formula and the Shinkansen design loads are used. It is found that the overturning of rail changes corresponding to the change of the stiffness of track pad and the ratio of lateral force to wheel load. Moreover, it is found that the analysis model can have influence on the results. Through these procedure, minimum spring coefficient of track pad is estimated.

• Journal of Internet Computing and Services
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• v.24 no.6
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• pp.91-98
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• 2023

Recently, according to development of artificial intelligence, a wide range of industry being automatic and optimized. Also we can find out some research of using supervised learning for deteceting defect of railway in domestic rail industry. However, there are structures other than rails on the track, and the fastener is a device that binds the rail to other structures, and periodic inspections are required to prevent safety accidents. In this paper, we present a method of reducing cost for labeling using semi-supervised and transfer model trained on rail fastener data. We use Resnet50 as the backbone network pretrained on ImageNet. At first we randomly take training data from unlabeled data and then labeled that data to train model. After predict unlabeled data by trained model, we adopted a method of adding the data with the highest probability for each class to the training data by a predetermined size. Futhermore, we also conducted some experiments to investigate the influence of the number of initially labeled data. As a result of the experiment, model reaches 92% accuracy which has a performance difference of around 5% compared to supervised learning. This is expected to improve the performance of the classifier by using relatively few labels without additional labeling processes through the proposed method.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.44 no.1
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• pp.41-48
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• 2024

In 2017, the Ministry of the Interior and Safety conducted research for the revision of seismic design standards and performed studies on standard design response spectra. As a result, the Common Application Guidelines for Seismic Design Standards were introduced, and these guidelines have been implemented in the national design standards of the Ministry of Land, Infrastructure, and Transport for practical use. However, it should be noted that the research for proposing standard design response spectra during the 2017 revision was conducted before the occurrence of the significant seismic events in South Korea, such as the 2016 Gyeongju Earthquake and the 2017 Pohang Earthquake. To account for these recent major earthquakes, this study adjusted the standard design spectra based on the records of the 2016 Gyeongju Earthquake and the 2017 Pohang Earthquake and conducted ground response analyses accordingly. The results revealed variations in peak ground acceleration (PGA) at the ground surface even within the same ground classification. It was confirmed that this variation can lead to overestimation or underestimation of seismic loads.