• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.6
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• pp.93-101
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• 2022

RC Slab bridges in Korea account for more than 70% of the total bridges for more than 20 years of service. As the number of aging structures increases, the importance of safety diagnosis and maintenance of structures increases. For highway bridges, cracks are a main cause of deck deterioration, which is very closely related to the decrease in bridge durability and service life. In addition, the damage rate of expansion joints and bearings accounts for approximately 73% higher than that of major members. Therefore, this study defined damage scenarios combined with devices damages and deck deterioration. The stress distribution and maximum stress on the deck were then evaluated using design vehicle load and daily temperature gradient for single and combined damage scenarios. Furthermore, this study performed damage-spread analysis and predicted condition ratings according to a deck deterioration model generated from the inspection and diagnosis history data of cracks. The heterogeneous damages combined with the member damages of expansion joints and bearings increased the rate of crack area and damage spread, which accelerated the time to reach the condition rating of C. Therefore, damage to bridge members requires proper and prompt repair and replacement, and otherwise it can cause the damage to bridge deck and the spread of the damage.

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.429-430
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• 2008

본 논문은 전기출력이 1400 MWe급으로 개발된 첨단 원자력 발전소인 APR1400(신형겨수로 1400) 제어계통에 적용되는 디지털시스템의 설계 및 성능 검증을 위해 개발 중인 디지털제어계통 검증시스템에 관한 것이다. APR1400 디지털제어계통은 발전소 출력 제어 및 안전운전과 관련 된 중요 기능들을 수행하며, 기존 원자력발전소와 달리 단일 디지털 Platform을 적용하고, Multi-Loop 개념과 네트워크을 적용하여 Controller와 케이블 수량을 줄인 특징을 가지고 있다. 이와 같을 설계는 지금가지 원자력발전소에는 적용된 적이 없기 때문에 사용자 측면에서는 디지털 제어 계통 설계 및 성능 관점에서의 검증을 위한 시스템이 요구되었다. 현재는 APR1400 시뮬레이터(발전소 모델링을 통한 모의시스템)를 이용한 검증시스템을 1차적으로 구축한 상태에 있으며, 시스템 전체 시험을 진행 중에 있다. 특히, 이번에 개발 중인 검증시스템은 구성이 간단하고 사용이 편리한 장점을 지니고 있을 뿐만 아니라 다양한 고장상황을 재현해 봄으로써 디지털제어계통의 성능을 확인해 볼 수 있는 특징을 보유하고 있다. 본 검증시스템의 활용방안으로는 첫째, 계통설계의 구현 가능성 관점에서의 확인시험을 수행하는 방안, 둘째, 발전소 시운전 착수 전 시운전요원 교육에 활용하는 방안, 셋째, 발전소 설계 변경 필요 시 설계 변경에 따른 영향 파악, 넷째, 디지털제어계통 유지보수 기술 습득 등에 효과적으로 활용 할 수 있을 것으로 본다. AFR1400 디지털제어계통은 현재 건설 중인 신고리 3,4호기 원자력발전소에 적용될 예정이며, 향후에는 해외 원자력 수출을 위한 기반기술로 활용될 수 있을 것으로 확신한다.

• Journal of Korea Multimedia Society
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• v.13 no.8
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• pp.1163-1170
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• 2010

In this paper, in order to develop a remote progress management system through the Internet, we show a design method to make easy maintenance by developing the system with both the JAVA language and GoF Design Patterns. For the system implementation, we added the RS232C and RS422/RS485 communication modules to PLC(Programmable Logic Controller) in the control box which provide the real time status data of machines. Also we set up the RS232C to Ethernet converter based on wireless environment to communicate the PLC control data. We use JAVA Swing components to implement the multi-tier architecture system supported the GUI of the Applet and Frame at the same time so that the manager grasps the progress of work easily at the remote machines through the Internet. The key objective of the multi-tier architecture is to share resources among clients, this proposed system can help to develop the software to control the remote machine, and also it has the advantage that developer who wants to make a similar software can make easy to add new function reusing the existing codes.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.8
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• pp.5695-5706
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• 2015

Recently adoption of BIM technology for building renovation and remodeling has been increased in construction industry. However most buildings have trouble in 2D drawing-based BIM modeling, because 2D drawings have not been updated real situations continually. Applying reverse engineering, this study analysed the point cloud data structure and the process for guideline of reverse engineering of architectural MEP, and deducted the relating considerations. To active usage of 3D scanning technique in domestic, the objective of this study is to analyze the point cloud data processing from real site with terrestrial LiDAR and the process from data gathering to data acquisition.

• Journal of the Korean Society of Systems Engineering
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• v.18 no.1
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• pp.1-13
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• 2022

The Yongin Light Rail train was manufactured by Bombardier Transportation in Canada in 2008 and is a privately invested railway line that has been operating in Yongin-si, Gyeonggi-do, since 2013. When the frequency of train failure increases due to aging, and there is a delay in the delivery period of imported parts used in the Bombardier manufactured trains, timely vehicle maintenance may not be performed due to lack of parts. To solve this problem, it is necessary to build a 'vehicle parts maintenance demand forecasting system' that analyzes the accurate and actual maintenance demand annual based on the condition of vehicle parts. The full scope of analysis in this paper analyzes failure data from various angles after opening of Yongin light rail vehicle to analyze failure patterns for each part and identify replacement cycles according to possible failures and consumption of parts. Based on this study, it is expected that Yongin Light Rail's maintenance system will change from the existing time-based replacement (TBM) concept to the condition-based maintenance (CBM) concept. It is expected that this study will improve the efficiency of the Yongin Light Rail maintenance system and increase vehicle availability. This paper is a fundamental for establishing of a system for predicting the replacement timing of vehicle parts for Yongin Light Rail. It reports the results of data analysis on some vehicle parts.

• Journal of the Society of Disaster Information
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• v.16 no.2
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• pp.276-290
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• 2020

Purpose: The construction history of domestic port facilities has been more than 100 years, and until recently, modern facilities have been continuously built and expanded. However, it is not easy to keep the required performance conditions at the time of initial construction due to changes in the marine environment and increase in volume. In particular, in the case of harbor structures that have a long service life, safety performance and function management are becoming very important due to the increase in the size of ships, the increasing frequency of use, and the increase in the scale of natural disasters. Method: Therefore, this study investigates the state change by structural type of port facilities and analyzes the rehabilitation activities and the history that contribute to the performance improvement and life extension activities. Result: Through this, we distinguished between performance improvement cost (CAPEX) and repair maintenance activity (OPEX) that can be used to establish port facility maintenance strategy, and suggested cost model that can be used to establish maintenance strategy. Conclusion: These studies are expected to contribute greatly to mid- to long-term investment decisions.

• Journal of Korean Tunnelling and Underground Space Association
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• v.22 no.5
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• pp.515-528
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• 2020

Underground concrete structures are usually designed to be used for decades, but in recent years, many of them are nearing their original life expectancy. As a result, it is necessary to promptly inspect and repair the structure, since it can cause lost of fundamental functions and bring unexpected problems. Therefore, personnel-based inspections and repairs have been underway for maintenance of underground structures, but nowadays, objective inspection technologies have been actively developed through the fusion of deep learning and image process. In particular, various researches have been conducted on developing a concrete crack detection algorithm based on supervised learning. Most of these studies requires a large amount of image data, especially, label images. In order to secure those images, it takes a lot of time and labor in reality. To resolve this problem, we introduce a method to increase the accuracy of crack area detection, improved by 0.25% on average by applying adversarial learning in this paper. The adversarial learning consists of a segmentation neural network and a discriminator neural network, and it is an algorithm that improves recognition performance by generating a virtual label image in a competitive structure. In this study, an efficient deep neural network learning method was proposed using this method, and it is expected to be used for accurate crack detection in the future.

• The KIPS Transactions:PartA
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• v.13A no.1 s.98
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• pp.45-52
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• 2006

To perform on-line maintenance for Distributed Information System, it is indispensable to disseminate files to participant nodes in the network. When users' requests for file deployment occur simultaneously in a short period a deployment server falls into overload phase, which is often called Flash Crowds. h common solution to avoid Flash Crowds is to increase hardware capacity. In this paper, we propose a software solution based on P2P, which does not cost any additional expense. In the proposed solution, nodes in the network are grouped into subnetworks one of which is composed of only neighboring nodes. In each subnetwork, copies of deployment files can be transferred to each other. Consequently, it brings about the effect of load balancing in deployment server. To raise the effectiveness, target files for deployment are packed into one package. Before being transferred, each package is divided into multiple equal-sized segments. A deployment server in a normal phase transmits a package requested from nodes in segment units. However a deployment server is overloaded, if segments already exist in the subnetwork participant nodes in the subnetwork receive necessary segments from neighboring nodes. In this paper, we propose data structures and algorithm for this approach and show performance improvement through simulation.

• Journal of the Korean Association of Geographic Information Studies
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• v.18 no.2
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• pp.105-119
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• 2015

The overseas expansion is essential to expand domestic geospatial industries in a state of saturation. But current overseas expansion method has be limited to expand global market. Inter-industry convergence strategies may be the most resonable alternative to expand global market through raising the expansion possibility to developing countries with ODA funds and to developed countries with converging global competitive industries. This research investigates various foreign developed and developing countries to draw each demand. As a result, easiness of convergence, confidentiality of information, complementarity of poor infrastructure, responsiveness of various demands and sustainability of system are needed to successful convergence on multiple industries. This research seeks convergence framework to meet this demands, and suggests each component. This convergence framework is consisted of geospatial convergence common framework, inter-industry convergence model and institutional supporting system for overseas expansion.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.4
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• pp.939-949
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• 2017

Prognostics and health management(PHM) is actively utilized by industry as an essential technology focusing on accurately monitoring the health state of a system and predicting the remaining useful life(RUL). An effective PHM is expected to reduce maintenance costs as well as improve safety of system by preventing failure in advance. With these advantages, PHM can be applied to the battery system which is a core element to provide electricity for devices with mobility, since battery faults could lead to operational downtime, performance degradation, and even catastrophic loss of human life by unexpected explosion due to non-linear characteristics of battery. In this paper we mainly review a recent progress on various models for predicting RUL of battery with high accuracy satisfying the given confidence interval level. Moreover, performance evaluation metrics for battery prognostics are presented in detail to show the strength of these metrics compared to the traditional ones used in the existing forecasting applications.