• Journal of the Earthquake Engineering Society of Korea
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• v.25 no.6
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• pp.305-314
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• 2021

The Gyeongju and Pohang earthquakes caused damages to many cultural properties; particularly, stone pagoda structures were significantly damaged among masonry cultural properties. To preserve these structures, it is necessary to understand their dynamic behavior characteristics under earthquakes. Analyses on such areas as deformation, frequency, maximum acceleration, permanent displacement, sliding, and rocking have to be performed. Although many analytical studies have already been conducted, dynamic behavior studies based on experiments are insufficient. Therefore, this study analyzed dynamic behavior characteristics by performing a shaking table experiment on a three-story stone pagoda structure at the Cheollongsa temple site damaged by the Gyeongju earthquake. As a result of the experiment, the displacements of stylobates did not occur significantly, but the tower body parts rotated. In particular, the rotation of the 1F main body stone was relatively larger than that of the other chief body stones because the 1F main body stone is relatively more slender than the other parts. In addition, the decorative top was identified as the component most vulnerable to sliding. This study found that the 1F main body stone is vulnerable to rocking, and the parts located on the upper part are more vulnerable to sliding.

• Journal of Auto-vehicle Safety Association
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• v.13 no.4
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• pp.7-13
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• 2021

This paper presents an vulnerable road user (VRU) classification and tracking algorithm using vision and LiDAR sensor fusion method for urban autonomous driving. The classification and tracking for vulnerable road users such as pedestrian, bicycle, and motorcycle are essential for autonomous driving in complex urban environments. In this paper, a real-time object image detection algorithm called Yolo and object tracking algorithm from LiDAR point cloud are fused in the high level. The proposed algorithm consists of four parts. First, the object bounding boxes on the pixel coordinate, which is obtained from YOLO, are transformed into the local coordinate of subject vehicle using the homography matrix. Second, a LiDAR point cloud is clustered based on Euclidean distance and the clusters are associated using GNN. In addition, the states of clusters including position, heading angle, velocity and acceleration information are estimated using geometric model free approach (GMFA) in real-time. Finally, the each LiDAR track is matched with a vision track using angle information of transformed vision track and assigned a classification id. The proposed fusion algorithm is evaluated via real vehicle test in the urban environment.

• International Journal of Internet, Broadcasting and Communication
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• v.14 no.1
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• pp.182-187
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• 2022

This study aims to study non-rechargeable wrist-type smart bands for those vulnerable to the digital environment. The transition to the digital age means improving the efficiency of human life and the convenience of management. In the digital age, it can be a very convenient infrastructure for the digital generation, but otherwise, it can cause inconvenience. COVID-19 is spreading non-face-to-face culture. The reality is that the vulnerable are complaining of discomfort in non-face-to-face culture. The core of the digital environment is smartphones. Digital life is spreading around smartphones. Technology that drives the digital environment is the core technology of the Fourth Industrial Revolution. The technologies are lot, big data, Blockchain, Smart Mobility, and AI. Related technologies based on these technologies include digital ID cards, digital keys, and nfc technologies. Non-rechargeable wrist-type smart bands based on related technologies can be conceptualized. Through these technologies, blind people can easily access books and manage their ID cards conveniently and efficiently. In particular, access authentication is required wherever you go due to COVID-19, which can be used as a useful tool for the elderly who feel uncomfortable using smartphones. It can also eliminate the inconvenience of the elderly finding or losing their keys.

• The Journal of the Convergence on Culture Technology
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• v.8 no.5
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• pp.597-602
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• 2022

In construction sites, many accidents occur without supervisors during night work, early work, and lunchtime work outside of regular working hours. The purpose of this study is to measure the safety level of workers and to provide basic data for preventing accidents during vulnerable times by analyzing the opinions of expert groups on working conditions. Working conditions were divided into four areas: basic conditions, physical environment, social environment, and physiological factors. After examining the correlation between the priority considerations determined by Analytic Hierarchy Process (AHP) and the safety level of workers investigated in advance, management plans for each factor was derived.

• Journal of Korean Association for Spatial Structures
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• v.23 no.2
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• pp.79-90
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• 2023

Existing reinforced concrete (RC) frame buildings have seismic vulnerabilities because of seismically deficient details. In particular, since cumulative damage caused by successive earthquakes causes serious damage, repair/retrofit rehabilitation studies for successive earthquakes are needed. This study investigates the repair effect of fiber-reinforced polymer jacketing system for the seismically-vulnerable building structures under successive earthquakes. The repair modeling method developed and validated from the previous study was implemented to the building models. Additionally, the main parameters of the FRP jacketing system were selected as the number of FRP layers associated with the confinement effects and the installation location. To define the repair effects of the FRP jacketing system with the main parameters, this study conducted nonlinear time-history analyses for the building structural models with the various repairing scenarios. Based on this investigation, the repair effects of the damaged building structures were significantly affected by the damage levels induced from the mainshocks regardless of the retrofit scenarios.

• Journal of Environmental Science International
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• v.32 no.3
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• pp.149-159
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• 2023

This study aimed to improve the level of satisfaction and service quality of a forest experience education program for vulnerable social groups by administering a survey problems of the program and suggested improvements. 428 participants in the program. Reliability analysis of the survey yielded values of, Cronbach's α value was higher than 0.8 for all items, indicating very high reliability. Importance-performance analysis (IPA), a method of measuring and comparing the degree of satisfaction, found two factors: "first need for correction" which included "diversity of programs" and "professionalism of programs"; and "the need for sustained effort" which included "benefits of programs", "the role of program instructors" and "the interest of programs". Previously, forest experience education focused on programs involving base expansion and promotion, or quantitative expansion education. Therefore, this study is meaningful in providing basic data on forest experience education for vulnerable social groups.

• Journal of Forest and Environmental Science
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• v.39 no.4
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• pp.213-224
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• 2023

As abnormal weather events due to climate change continue to rise, landslide damage is also increasing. Given the substantial time and financial resources required for post-landslide recovery, it becomes imperative to formulate a proactive response plan. In this regard, landslide susceptibility analysis has emerged as a valuable tool for establishing preemptive measures against landslides. Accordingly, this study conducted an annual landslide susceptibility analysis using the history of landslides that occurred over many years in the Jeolla region, and analyzed areas with a high potential for landslides in the Jeolla region. The analysis employed an ensemble model that amalgamated 10 data-based models, aiming to mitigate uncertainties associated with a single-model approach. Furthermore, based on the cumulative data regarding landslide susceptible areas, this research identified regions vulnerable to recurring landslide damage in Jeolla region and proposed specific strategies for utilizing this information at various levels, including local government initiatives, adaptation plan development, and development approval processes. In particular, this study outlined approaches for local government utilization, the determination of adaptation plan types, and considerations for development permits. It is anticipated that this research will serve as a valuable opportunity to underscore the significance of information concerning regions vulnerable to recurring landslide damage.

• The Journal of Information Systems
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• v.33 no.1
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• pp.69-90
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• 2024

Purpose In this paper, among the four information vulnerable groups(disabled, elderly, low-income, farmers and fishermen), the mediating effect of digital device usage attitudes in the effect of digital information utilization level of farmers and fishermen with a large digital information gap with the general public on life satisfaction was verified. Design/methodology/approach This study summarizes existing research related to the digital information gap between farmers and fishermen, and the empirical analysis is based on hierarchical regression analysis based on the 2022 Digital Information Gap Report (survey data on 2,200 farmers and fishermen) published by the Korea Intelligence Information Society Promotion Agency. Among the four major information vulnerable groups (the disabled, the elderly, low-income groups, and farmers and fishermen), attitudes toward using digital devices were examined in terms of the impact of the level of digital information use on life satisfaction among farmers and fishermen, who have a relatively large digital information gap with the general public. It was verified as a mediating effect. Findings As a result of the empirical analysis, attitudes toward the use of digital devices were found to play a mediating role in the impact of the level of digital information use on life satisfaction.

• Journal of Information Technology Applications and Management
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• v.31 no.3
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• pp.39-52
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• 2024

The development of autonomous driving technology is expected to bring about a major change in the mobility rights of the transportation vulnerable. It is very important to identify user requirements in developing autonomous vehicles and service technologies for the transportation vulnerable. User requirements were derived for the wheelchair disabled and the walking disabled. Through focus interviews, a total of 58 requirements were derived for wheelchair-using disabled people and 53 requirements for walking disabled people. A Kano survey was conducted on 33 wheelchair disabled and 34 walking disabled. After that, the quality types of functional requirements in terms of autonomous vehicles and service environment development were analyzed using the Kano model. Priority analysis was conducted on the functions required by the wheelchair disabled and the walking disabled. The results of this study can be used as basic data to determine the priorities of user function requirements in the early stages of autonomous vehicle and service technology development.

• Journal of the Earthquake Engineering Society of Korea
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• v.28 no.5
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• pp.275-283
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• 2024

Many school buildings are vulnerable to earthquakes because they were built before mandatory seismic design was applied. This study uses machine learning to develop an algorithm that rapidly constructs an optimal reinforcement scheme with simple information for non-ductile reinforced concrete school buildings built according to standard design drawings in the 1980s. We utilize a decision tree (DT) model that can conservatively predict the failure type of reinforced concrete columns through machine learning that rapidly determines the failure type of reinforced concrete columns with simple information, and through this, a methodology is developed to construct an optimal reinforcement scheme for the confinement ratio (CR) for ductility enhancement and the stiffness ratio (SR) for stiffness enhancement. By examining the failure types of columns according to changes in confinement ratio and stiffness ratio, we propose a retrofit scheme for school buildings with masonry walls and present the maximum applicable stiffness ratio and the allowable range of stiffness ratio increase for the minimum and maximum values of confinement ratio. This retrofit scheme construction methodology allows for faster construction than existing analysis methods.