• Journal of the Korean Association of Geographic Information Studies
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• v.25 no.1
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• pp.1-15
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• 2022

In order to trust and use autonomous vehicles, safe driving on the road must be guaranteed. For this, the first infrastructure to be equipped with autonomous driving is traffic safety facility. On the other hand, autonomous vehicles(Level 3) and general vehicles are driving on the road, it is necessary to additionally manage existing general traffic safety facilities. In this study, a field management system for traffic safety facilities based on autonomous driving infrastructure was studied, and a pilot field management system was implemented in the demonstration area(Pangyo). The pilot system consists of a GNSS(Global Navigation Satellite System) receiver, a field management equipment, and a field management app. As a result of field demonstration,, it was confirmed that traffic safety facility information was easily transmitted and received even in downtown areas and that could be efficiently operated and managed. It is expected that the results of this study will be used as reference materials for the spread of autonomous driving infrastructure to local governments and infrastructure construction in the future.

• Journal of Convergence for Information Technology
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• v.11 no.11
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• pp.172-177
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• 2021

As part of the digital era, a digital twin that simulates the weak part of a product by performing a stress test that reduces the lifespan of some expensive equipment that cannot be done in reality by accurately moving the real world to virtual reality is being actively used in the manufacturing industry. Due to the development of IoT, the digital twin, which accurately collects data collected from the real world and makes it the same in the virtual space, is mutually beneficial through accurate prediction of urban life problems such as traffic, disaster, housing, quarantine, energy, environment, and aging. Based on its action, it is positioned as a necessary tool for smart city construction. Although digital twin is widely applied to the manufacturing field, this study proposes a smart city model suitable for the 4th industrial revolution era by using it to smart cities and increasing citizens' safety, welfare, and convenience through the proposed model. In addition, when a digital twin is applied to a smart city, it is expected that more accurate prediction and analysis will be possible by real-time synchronization between the real and virtual by maintaining realism and immediacy through real-time interaction.

• Journal of the Society of Disaster Information
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• v.18 no.2
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• pp.269-279
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• 2022

Purpose: The purpose of this study is to develop a deep learning-based personal protective equipment detection model for disaster prevention at construction sites, and to apply it to actual construction sites and to analyze the results. Method: In the method of conducting this study, the dataset on the real environment was constructed and the developed personal protective equipment(PPE) detection model was applied. The PPE detection model mainly consists of worker detection and PPE classification model.The worker detection model uses a deep learning-based algorithm to build a dataset obtained from the actual field to learn and detect workers, and the PPE classification model applies the PPE detection algorithm learned from the worker detection area extracted from the work detection model. For verification of the proposed model, experimental results were derived from data obtained from three construction sites. Results: The application of the PPE recognition model to construction site brings up the problems related to mis-recognition and non-recognition. Conclusions: The analysis outcomes were produced to apply the object recognition technology to a construction site, and the need for follow-up research was suggested through representative cases of worker recognition and non-recognition, and mis-recognition of personal protective equipment.

• Smart Structures and Systems
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• v.14 no.5
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• pp.917-942
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• 2014

Multivariate statistics based damage detection algorithms employed in conjunction with novel sensing technologies are attracting more attention for long term Structural Health Monitoring of civil infrastructure. In this study, two practical data driven methods are investigated utilizing strain data captured from a 4-span bridge model by Fiber Bragg Grating (FBG) sensors as part of a bridge health monitoring study. The most common and critical bridge damage scenarios were simulated on the representative bridge model equipped with FBG sensors. A high speed FBG interrogator system is developed by the authors to collect the strain responses under moving vehicle loads using FBG sensors. Two data driven methods, Moving Principal Component Analysis (MPCA) and Moving Cross Correlation Analysis (MCCA), are coded and implemented to handle and process the large amount of data. The efficiency of the SHM system with FBG sensors, MPCA and MCCA methods for detecting and localizing damage is explored with several experiments. Based on the findings presented in this paper, the MPCA and MCCA coupled with FBG sensors can be deemed to deliver promising results to detect both local and global damage implemented on the bridge structure.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.40 no.3
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• pp.195-206
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• 2022

The primary purpose of this study was to analyze assessment factors by identifying and prioritizing live fire shooting area requirements using the AHP (Analytic Hierarchy Process) technique. Derived assessment factors for candidate sites were divided into six categories. Of these, four categories (base-to-range distance, weapon danger area, range terrain, and size) were in the realm of physical geography while the remaining two (land use and proximity to habitation) fell under the general heading of human geography. A case study was also conducted to select several alternative firing ranges using derived factors. The optimal location was analyzed by evaluating the candidate site using each assessment factor. As a result, it was found that assessment factors applying to GIS (Geographic Information System) were able to effectively analyze a suitable location for relocation of the focal training facility, taking into consideration public-safety issues, training requirements, and residents' past and likely future complaints. Through this process, it can prevent the waste of time and effort in determining an optimal location for a live fire shooing range.

• Smart Structures and Systems
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• v.20 no.1
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• pp.75-83
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• 2017

Effectively monitoring the concrete cracks is an urgent question to be solved in the structural safety monitoring while cracks in hydraulic concrete structures are ubiquitous. In this paper, two experiments are designed based on the measuring principle of Pulse-Pre pump Brillouin Optical Time Domain Analysis (PPP-BOTDA) utilizing Brillouin optical fiber sensor to monitor concrete cracks. More specifically, "V" shaped optical fiber sensor is proposed to determine the position of the initial crack and the experiment illustrates that the concrete crack position can be located by the mutation position of optical fiber strain. Further, Brillouin distributed optical fiber sensor and preinstall cracks are set at different angles and loads until the optical fiber is fractured. Through the monitoring data, it can be concluded that the variation law of optical fiber strain can basically reflect the propagation trend of the cracks in hydraulic concrete structures.

• Smart Structures and Systems
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• v.24 no.6
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• pp.783-791
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• 2019

Prefabricated reinforced-concrete shear walls are used extensively in building structures because they are convenient to construct and environmentally sustainable. To make large walls easier to transport, they are divided into smaller segments and then assembled at the construction site using a variety of connection methods. The present paper proposes a precast shear wall assembled using steel shear keys, wherein the shear keys are fixed on the embedded steel plates of adjacent wall segments by combined plug and fillet welding. The anchoring strength of shear keys is known to affect the mechanical properties of the wall segments. Loading tests were therefore performed to observe the behavior of precast shear wall specimens with different anchoring components for shear keys. The specimen with insufficient strength of anchoring components was found to have reduced stiffness and lateral resistance. Conversely, an extremely high anchoring strength led to a short-column effect at the base of the wall segments and low deformation ability. Finally, for practical engineering purposes, a design approach involving the safety coefficient of anchoring components for steel shear keys is suggested.

• Smart Structures and Systems
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• v.29 no.5
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• pp.715-728
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• 2022

Recently, numbers of long span pedestrian suspension bridges have been constructed worldwide. While recent tragedies regarding pedestrian suspension bridges have shown how these bridges can wreak havoc on the society, there are no specific guidelines for construction standards nor safety inspections yet. Therefore, a structural health monitoring system that could help ensure the safety of pedestrian suspension bridges are needed. System identification is one of the popular applications for structural health monitoring method, which estimates the dynamic system. Most of the system identification methods for bridges are currently adapting output-only system identification method, which assumes the dynamic load to be a white noise due to the difficulty of measuring the dynamic load. In the case of pedestrian suspension bridges, the pedestrian load is within specific frequency range, resulting in large errors when using the output-only system identification method. Therefore, this study aims to develop a system identification method for pedestrian suspension bridges considering both input and output of the dynamic system. This study estimates the location and the magnitude of the pedestrian load, as well as the dynamic response of the pedestrian bridges by utilizing artificial intelligence and computer vision techniques. A simulation-based validation test was conducted to verify the performance of the proposed system. The proposed method is expected to improve the accuracy and the efficiency of the current inspection and monitoring systems for pedestrian suspension bridges.

• Smart Structures and Systems
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• v.33 no.1
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• pp.27-39
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• 2024

The effectiveness of conventional tuned liquid dampers (TLDs) in controlling the wind-induced response of tall flexible structures has been indicated. However, the impaired control effect in the detuning condition or a considerably high mass cost of liquid may be incurred in ensuring the high-level serviceability. To provide an efficient TLD-based solution for wind-induced vibration control, this study proposes a serviceability-oriented optimal design method for isolated TLDs (ILDs) and derives analytical design formulae. The ILD is implemented by mounting the TLD on the linear isolators. Stochastic response analysis is performed for the ILD-equipped structure subjected to stochastic wind and white noise, and the results are considered to derive the closed-form responses. Correspondingly, an extensive parametric analysis is conducted to clarify a serviceability-oriented optimal design framework by incorporating the comfort demand. The obtained results show that the high-level serviceability demand can be satisfied by the ILD based on the proposed optimal design framework. Analytical design formulae can be preliminarily adopted to ensure the target serviceability demand while enhancing the structural displacement performance to increase the safety level. Compared with conventional TLD systems, the ILD exhibits higher effectiveness and a larger frequency bandwidth for wind-induced vibration control at a small mass ratio.

• Korean Journal of Computational Design and Engineering
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• v.18 no.2
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• pp.83-92
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• 2013

IFC based open BIM has internationally developed as a solution for interoperability problem among different software applications. Despite much interest and effort, the open BIM technologies are rarely introduced to the construction industry and need more technical development for a practical application as well. This research aims to develop automated code checking modules for quality assurance process of BIM data. The research have analyzed domestic regulations focusing on super-tall buildings and developed open BIM-based code checking modules for the evacuation regulations. The modules are able to validate evacuation regulations such as installation of emergency elevator and fire safety zone. The authors expect to improve the process of BIM quality assurance and enhance the quality of BIM data by this research on automated checking system.