• Journal of the Korea Institute of Building Construction
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• v.16 no.2
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• pp.133-140
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• 2016

The amount of labor input in a construction project is used as source data to estimate construction cost and to understand the productivity of the construction industry. However, there is a significant difference between the standard of estimation and the actual amount of labor input, and a plan is needed to resolve this problem. For this reason, to establish a system with which the actual amount of labor input can be inputted in a more accurate and simpler manner, a new method is proposed in this study. In the new method, a digital pen is used to minimize the difference from traditional handwriting on paper using a pen, and eliminate the redundant input of information. This study is expected not only to reduce the actual amount of labor input but also to contribute to the productivity of construction cost estimate through the sharing or utilization of the information on the web.

• Smart Structures and Systems
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• v.30 no.1
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• pp.35-47
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• 2022

Data-driven engineering is crucial for information delivery between design, fabrication, assembly, and maintenance of prefabricated structures. Design for manufacturing and assembly (DfMA) is a critical methodology for prefabricated bridge structures. In this study, a novel concept of digital engineering model that combined existing knowledge of DfMA with object-oriented parametric modeling technologies was developed. Three-dimensional (3D) geometry models and their data models for each phase of a construction project were defined for information delivery. Digital design models were used for conceptual design, including aesthetic consideration and possible variation during fabrication and assembly. The seismic performance of a bridge pier was evaluated by linking the design parameters to the calculated moment-curvature curves. Control parameters were selected to consider the tolerance control and revision of the digital models. Digitalized fabrication of the prefabricated members was realized using the digital fabrication model with G-code for a concrete printer or a robot. The fabrication error was evaluated and the design digital models were updated. The revised fabrication models were used in the preassembly simulation to guarantee constructability. For the maintenance of the bridge, the as-built information was defined for the prefabricated bridge piers. The results of this process revealed that data-driven information delivery is crucial for lifecycle management of prefabricated bridge piers.

• Journal of Internet Computing and Services
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• v.23 no.1
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• pp.39-47
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• 2022

Digital Twin is positioned as one of the establishment of a digital management system for core infrastructure in terms of collecting real data and implementing virtual space. However, there are currently no integrated three-dimensional marine information analysis tools and technologies in Korea, and unlike land, new 3D modeling technologies and data processing technologies are required to digitize flexible marine information, but there are limitations in implementation. Therefore, this study aims to present development directions in four areas: structure, data, modeling, and utilization platform of marine digital twin by analyzing trends related to marine digital twin and digital twin technology elements.

• International conference on construction engineering and project management
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• 2020.12a
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• pp.510-519
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• 2020

Within an intelligent automated cyber-physical system, the realization of the autonomous mechanism for data collection, data integration, and data analysis plays a critical role in the design, development, operation, and maintenance of such a system. This construct is particularly vital for fault-tolerant route-finding systems that rely on the imprecise GPS location of the vehicles to properly operate, timely plan, and continuously produce informative feedback to the user. More essentially, the integration of digital twins with cyber-physical route-finding systems has been overlooked in intelligent transportation services with the capacity to construct the network routes solely from the locations of the operating vehicles. To address this limitation, the present study proposes a conceptual architecture that employs digital twin to autonomously maintain, update, and manage intelligent transportation systems. This virtual management simulation can improve the accuracy of time-of-arrival prediction based on auto-generated routes on which the vehicle's real-time location is mapped. To that end, first, an intelligent transportation system was developed based on two primary mechanisms: 1) an automated route finding process in which predictive data-driven models (i.e., regularized least-squares regression) can elicit the geometry and direction of the routes of the transportation network from the cloud of geotagged data points of the operating vehicles and 2) an intelligent mapping process capable of accurately locating the vehicles on the map whereby their arrival times to any point on the route can be estimated. Afterward, the digital representations of the physical entities (i.e., vehicles and routes) were simulated based on the auto-generated routes and the vehicles' locations in near-real-time. Finally, the feasibility and usability of the presented conceptual framework were evaluated through the comparison between the primary characteristics of the physical entities with their digital representations. The proposed architecture can be used by the vehicle-tracking applications dependent on geotagged data for digital mapping and location tracking of vehicles under a systematic comparison and simulation cyber-physical system.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2004.11a
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• pp.571-574
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• 2004

It is rapidly expanding to provide Home Digital Service based on the Home Network System in intelligent apartment. Fortunately, Korea has one of the highest rates of Internet penetration and access in the world. Construction companies used the Home Network system as a strategy of differentiation and it is available to the customers to raise their asset value. Besides, the government has a positive response to accept the new movements to make the digital environment with 'u-Korea (Ubiquitous Korea)' as the slogan. However, the level of providing Home Digital Service is actually at the beginning. The develop the home network industry more effectively, the related industries' cooperation is essential. The purpose of this study is to propose a providing model of Home Network System for the construction company and to make a method to response the fast change of technology development and customer's request at the point of construction companies' view.

• Journal of the Korea Institute of Building Construction
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• v.16 no.2
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• pp.177-183
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• 2016

The daily report includes the most detailed information and various daily planning and performance data recorded at a site, and includes work types, the number of workers, and the equipment and materials used. However, in the daily reporting process, some information can be omitted or distorted or even made redundant due to there being several steps of manual input. For this reason, the daily report is utilized for a simple report rather than for an appropriate purpose. Thus, to resolve the issues of the existing daily report system mentioned above, a daily report system using a digital pen was developed and then applied to an actual construction site to verify its applicability. As a result, it was found that 96.610% recognition accuracy of handwritten letters could be achieved. In addition, it was no longer necessary to enter the same information multiple times and no additional training or education for using a mobile device was needed. The digital pen-based daily report program developed in this study is expected to contribute to an improvement of information management efficiency and site document management work by addressing the problems of the existing report system.

• Journal of the Korea Institute of Building Construction
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• v.23 no.1
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• pp.93-102
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• 2023

Building supervision can be defined as a major task that involves managing and supervising the construction process to support the creation of high-quality results. To successfully perform supervision work, it is necessary to collect various information generated in uncertain field conditions, but today, supervision is performed based on documents such as reports, so there are limitations in collecting information. In fact, it has also been reported that the recent collapse of an apartment building in Korea was caused by limitations of information communication in th supervision work. Accordingly, this study analyzed the types of digital technologies that can be used to improve the efficiency of building supervision work, and presented the prioritized application of them. Priority application was quantitatively evaluated using analytic hierarchy process on data through a survey. It is expected that the results of this study can be used as basic data to set the roadmap of digital technology for building supervision in the future.

• KEPCO Journal on Electric Power and Energy
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• v.7 no.2
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• pp.285-293
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• 2021

The construction of underground structures such as power supply lines, communication lines, utility tunnels has significantly increased worldwide for improving urban aesthetics ensuring citizen safety, and efficient use of underground space. Those underground structures are usually constructed along with vertical cylindrical shafts to facilitate their construction and maintenance. When constructing a vertical shaft through the open-cut method, the walls are mostly designed to be flexible, allowing a certain level of displacement. The earth pressure applied to the flexible walls acts as an external force and its accurate estimation is essential for reasonable and economical structure design. The earth pressure applied to the flexible wall is closely interrelated to the displacement of the surrounding ground. This study simulated stepwise excavation for constructing a cylindrical vertical shaft through a centrifugal model experiment. One quadrant of the axisymmetric vertical shaft and the ground were modeled, and ground excavation was simulated by shrinking the vertical shaft. The deformation occurring on the entire ground during the excavation was continuously evaluated through digital image analysis. The digital image analysis evaluated complex ground deformation which varied with wall displacement, distance from the wall, and ground depth. When the ground deformation data accumulate through the method used in this study, they can be used for developing shaft wall models in future for analyzing the earth pressure acting on them.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.11
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• pp.37-46
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• 2013

This paper proposes the boost type bidirectional zero current switching(ZCS) DC/DC converter of transformer series construction for electric vehicle operation using low voltage battery. This converter can high boost through the double voltage circuit and series construction of output part using two converters. This converter system has the advantages that bidirectional power transfer is excellent, size and making of transformer because of this converter keeps the transformation ratio to 1:1. Proposed DC/DC converter uses the ZCS method to decrease the switching loss. By replacing reactance ingredients of L-C resonance circuit for ZCS with leakage inductance ingredients of high frequency transformer and half-bridge capacitor it reduces system size and expense because of not add special reactor. It can confirm to output of high voltage to operate the electric vehicle with low voltage of input and operation of ZCS in all load region through the result of PSIM simulation and experiment.

• Korean Journal of Digital Imaging in Medicine
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• v.12 no.2
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• pp.103-111
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• 2010

A total of 200 hospital employees participated in this study from January 2009 to June 2010. For the survey, each participant was given necessary items for external health exams. Cronbach's alpha was calculated for the survey regarding wireless networks. There was a need for educating data processing workers in the medical field regarding fundamental information prior to wireless network construction. The reason is high scores would be collected, which would reflect knowledge regarding data processing used at hospitals and the differences between paper charts and electronic charts. However, low scores were obtained which reflected knowledge regarding the differences between wired and wireless networks and Mini-PACS. Time for each patient was shortened to a maximum of three minutes and minimum of one minute for treatment and transmitting medical images when comparing pre and post wireless network construction(p < 0.01). Scores from the pre and post construction survey increase 1.98, 1.65, and 1.43 points for activity in the health screening area, usage of space in the health screening vehicle, and patient information storage respectively(p < 0.05). The number of patients receiving external health screenings twelve times was 3,655 prior to construction of a wireless network system. However, the number increased to 4,265 after construction. The increasing percentage was 17% in total. Prior to construction, X-ray images were taken 527 times, but after construction of a wireless network, this number growed to 1,194 and it was 116% increase. The loss of patient's medical treatment charts was reduced from 19.8% to 18.7% after construction. We believe that educating medical workers on Mini-PACS and Mini-OCS Systems will not only increase their efficiency but also make patients receiving better treatment.