• 교육시설 논문지
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• 제27권1호
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• pp.3-10
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• 2020

Due to the frequent occurrence of large-scale disasters such as recent earthquakes, the problem of the safety of old school buildings has emerged. The need to secure safety management technology through constant monitoring is increasing in an attempt to supplement old school buildings with weak disaster response capabilities. Traditional research is approaching the development of an existing sensor-based risk precursor information monitoring system. However, unlike this, in this study, we will focus on the development of a data analysis platform as part of the development of a continuous monitoring system that can be prepared for earthquakes, collapses, and fires, based on constantly measured data. For this reason, the development of a safety diagnostic algorithm based on the optimal sensor-attached points and sensor data reflecting the fragile characteristics of old school buildings was derived. Utilizing this, a message and action manual system for each management / use entity of school buildings after retirement was constructed.

• Nuclear Engineering and Technology
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• 제52권2호
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• pp.381-396
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• 2020

Investigations of the commercial aircraft impact effect on nuclear island infrastructures have been drawing extensive attention, and this paper aims to perform the safety assessment of Generation III nuclear power plant (NPP) buildings subjected to typical commercial aircrafts crash. At present Part I, finite element (FE) models establishment and validations for both the aircrafts and NPP buildings are performed. (i) Airbus A320 and A380 aircrafts are selected as the representative medium and large commercial aircrafts, and the corresponding fine FE models including the skin, beam, fuel and etc. are established. By comparing the numerically derived impact force time-histories with the existing published literatures, the rationality of aircrafts models is verified. (ii) Fine FE model of the Chinese Zhejiang Sanao NPP buildings is established, including the detailed structures and reinforcing arrangement of both the containment and auxiliary buildings. (iii) By numerically reproducing the existing 1/7.5 scaled aircraft model impact tests on steel plate reinforced concrete (SC) panels and assessing the impact process and velocity time-history of aircraft model, as well as the damage and the maximum deflection of SC panels, the applicability of the existing three concrete constitutive models (i.e., K&C, Winfrith and CSC) are evaluated and the superiority of Winfrith model for SC panels under deformable missile impact is verified. The present work can provide beneficial reference for the integral aircraft crash analyses and structural damage assessment in the following two parts of this paper.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2022년도 가을 학술논문 발표대회
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• pp.229-230
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• 2022

According to the national building status, there are a total of 2.89 million buildings that are over 30 years old after completion, and the number is increasing by more than 70,000 to 80,000 buildings every year. As a result, the demand for demolition works is also increasing, and more than 3 to 4 collapse accidents occur steadily every year during demolition work. Major causes of accidents include non-compliance with plans, negligence of on-site supervisors, and failure to secure structural safety. Due to the strengthening of the Severe Disaster Punishment Act, there is growing interest in the demand for secure management of collapse detection during demolition works. Therefore, this study aims to investigate the applicability of real-time safety monitoring systems using a total station capable of 3D automatic displacement measurement in building demolition work for securing structural safety by the load changes during the demolition process.

• Smart Structures and Systems
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• 제18권3호
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• pp.585-599
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• 2016

Steel cables serve as the key structural components in long-span bridges, and the force state of the steel cable is deemed to be one of the most important determinant factors representing the safety condition of bridge structures. The disadvantages of traditional cable force measurement methods have been envisaged and development of an effective alternative is still desired. In the last decade, the vision-based sensing technology has been rapidly developed and broadly applied in the field of structural health monitoring (SHM). With the aid of vision-based multi-point structural displacement measurement method, monitoring of the tensile force of the steel cable can be realized. In this paper, a novel cable force monitoring system integrated with a multi-point pattern matching algorithm is developed. The feasibility and accuracy of the developed vision-based force monitoring system has been validated by conducting the uniaxial tensile tests of steel bars, steel wire ropes, and parallel strand cables on a universal testing machine (UTM) as well as a series of moving loading experiments on a scale arch bridge model. The comparative study of the experimental outcomes indicates that the results obtained by the vision-based system are consistent with those measured by the traditional method for cable force measurement.

• 한국구조물진단유지관리공학회 논문집
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• 제6권3호
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• pp.103-110
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• 2002

Maintenance monitoring of the tunnel which offers continuous data during and after tunneling has been applying to tunnels in order to meet the maintenance of tunnel and to confirm continuous security of the tunnel after tunneling. But, the maintenance monitoring of tunnel results for long period is not easy to find, and moreover, the rational analysis method on tunnel monitoring has not been established yet. In this study, the relationships between displacement and stress of the tunnel concrete lining using various analysis methods are compared with maintenance monitoring. The tunnel behavior were measured in the subway tunnel passing comparative soft the weathering and analyzed both security and mechanical characteristics of the tunnel concrete lining. Also, analyzed relationship between residual water pressure applied on tunnel design and one obtained by monitoring.

• Structural Monitoring and Maintenance
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• 제5권1호
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• pp.67-78
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• 2018

The stability of cutting slope influences the safety of railway operation, and how to identify the stability of the slope quickly and determine the rational monitoring plan is a pressing problem at present. In this study, the attribute recognition model of risk assessment for high cutting slope stability in the heavy haul railway is established based on attribute mathematics theory, followed by the consequent monitoring scheme design. Firstly, based on comprehensive analysis on the risk factors of heavy haul railway loess slope, collapsibility, tectonic feature, slope shape, rainfall, vegetation conditions, train speed are selected as the indexes of the risk assessment, and the grading criteria of each index is established. Meanwhile, the weights of the assessment indexes are determined by AHP judgment matrix. Secondly, The attribute measurement functions are given to compute attribute measurement of single index and synthetic attribute, and the attribute recognition model was used to assess the risk of a typical heavy haul railway loess slope, Finally, according to the risk assessment results, the monitoring content and method of this loess slope were determined to avoid geological disasters and ensure the security of the railway infrastructure. This attribute identification- risk assessment- monitoring design mode could provide an effective way for the risk assessment and control of heavy haul railway in the loess plateau.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.1545-1561
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• 2008

Among all transportations, railway transports have been promisingly offering excellent energy conservation and travelling time. Inevitably, they become a main role in not only transport goods but also passengers. With leap in development of technology, trains have tremendously enhanced their services in terms of speed, accessibility and comfort. However, the safety and ride quality have become a main issue as the train speed increased. The higher speeds have led the structural dynamics and health must be monitored from time to time to ensure that they are in good condition to provide reliable ride. Among all monitoring systems, the structural health monitoring (SHM) systems are imperative important due to its capability of in-situ monitoring and inherently reduce the maintenance frequencies and the huge associated cost. In this paper, SHM systems and the related non-destructive test and evaluation methods were discussed. The types of damages related to train vehicles as well as the damage hot spots are also included in this paper.

• 한국구조물진단유지관리공학회 논문집
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• 제6권2호
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• pp.145-155
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• 2002

It is essential for health monitoring of a cable-stayed bridge to provide more accurate and enough information from the sensors. In experimental modal testing, the chosen measurement locations and the number of measurements have a major influence on the quality of the results. The choice is often difficult for complex structures like a cable-stayed bridge. It is extremely important a cable-stayed bridge to minimize the number of sensing operations required to monitor the structural system. In order to obtain the desired accuracy for the structural test, several issues must take into consideration. Two important issues are the number and location of response sensors. There are usually several alternative locations where different sensors can be located. On the other hand, the number of sensors might be limited due to economic constraints. Therefore, techniques such as methodologies, algorithms etc., which address the issue of limited instrumentation and its effects on resolution and accuracy in health monitoring systems are paramount to a damage diagnosis approach. This paper discusses an optimum sensor placement criterion suitable to the identification of structural damage for continuous health monitoring. A Kinetic Energy optimization technique and an Effective Independence Method are analyzed and numerical and theoretical issues are addressed for a cable-stayed bridge. Its application to a cable-stayed bridge is discussed to optimize the sensor placement for identification and control purposes.

• Nuclear Engineering and Technology
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• 제56권5호
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• pp.1887-1894
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• 2024

Fatigue strength of the structural materials of lead-cooled fast reactors (LFRs) and accelerator-driven systems (ADS) may be degraded in liquid metal (Lead or lead-bismuth eutectic (LBE)) environments. The fatigue crack growth (FCG) data of structural materials in liquid LBE are necessary for damage tolerance design, safety assessment and life management of key equipment. A novel monitoring system for fatigue crack length was designed on the compliance method and the monitor technology of crack opening displacement (COD) of CT specimens by the linear variable differential transformers (LVDT) system. It can be used to predict the crack length by monitoring the COD of CT specimens in harsh high-temperature liquid LBE using a LVDT system. The prediction accuracy of this system was verified by FCG experiments in room temperature air and liquid LBE at 150, 250 and 350 ℃. The first results obtained in the FCG test for T91 steel in liquid LBE at 350 ℃ are presented.

• International Journal of Internet, Broadcasting and Communication
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• 제12권3호
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• pp.32-38
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• 2020

The deployment of geographically distributed wireless sensors has greatly elevated the capability of monitoring structural health in social-overhead capital (SOC) public infrastructures. This paper deals with the utilization of a distributed mobility management (DMM) approach for the deployment of wireless sensing devices in a structural health monitoring system (SHM). Then, a wireless sensing mechanism utilizing low-energy adaptive clustering hierarchy (LEACH)-based clustering algorithm for smart sensors has been analyzed to support the seamless data transmission of structural health information which is essentially important to guarantee public safety. The clustering of smart sensors will be able to provide real-time monitoring of structural health and a filtering algorithm to boost the transmission of critical information over heterogeneous wireless and mobile networks.