• Journal of the Korean Institute of Educational Facilities
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• v.27 no.1
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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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• v.50 no.4
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• pp.542-552
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• 2018

Operators face challenges to plan alternative countermeasures when no procedure exists to address the current plant state. A model-based approach is desired to aid operators in acquiring plant resources and deriving response plans. Multilevel flow modeling (MFM) is a functional modeling methodology that can represent intentional knowledge about systems, which is essential in response planning. This article investigates the capabilities of MFM to plan alternatives. It is concluded that MFM has a knowledge capability to represent alternative means that are designed for given ends and a reasoning capability to identify alternative functions that can causally influence the goal achievement. The second capability can be applied to find originally unassociated means to achieve a goal. This is vital in a situation where all designed means have failed. A technique of procedure synthesis can be used to express identified alternatives as a series of operations. A case of station blackout occurring at the boiling water reactor is described. An MFM model of a boiling water reactor is built according to the analysis of goals and functions. The accident situations are defined by the model, and several alternative countermeasures in terms of operating procedures are generated to achieve the goal of core cooling.

• Journal of KSNVE
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• v.9 no.1
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• pp.163-173
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• 1999

Precise and reasonable modelling is necessary and indispensable to the analysis of dynamic characteristics of mechanical structures. Also. the effective prediction of the change of modal properties due to the variation of design parameters is required especially for the application of finite element method to the structural dynamics problems. To meet those necessity and requirement, three model updating algorithms are proposed for finite element methods. Those algorithms are based on sensitivity analysis of the modal data obtained from experimental modal analysis(EMA) and analytical modal analysis(AMA). The adapted sensitivity analysis methods of the algorithms are 1)eigensensitivity(EGNS) method. 2)frequency response function sensitivity(FRFS) method. 3)sensitivity based element-by-element method (SBEEM), Singular value decomposition(SVD) is used for performing eigenanalysis and parameter estimation in the updating process. Those algorithms are applied to finite element of a plate and the updating capability of each algorithm is compared in terms of accuracy. reliability and stability of the updating process. It is shown that the model updating method using frequency response function is superior to the other methods in view of various updating capabilities.

• Journal of Mechanical Science and Technology
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• v.20 no.8
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• pp.1139-1148
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• 2006

This paper addresses the analytical modeling and dynamic response of the advanced composite rotating blade modeled as thin-walled beams and incorporating viscoelastic material. The blade model incorporates non-classical features such as anisotropy, transverse shear, rotary inertia and includes the centrifugal and coriolis force fields. The dual technology including structural tailoring and passive damping technology is implemented in order to enhance the vibrational characteristics of the blade. Whereas structural tailoring methodology uses the directionality properties of advanced composite materials, the passive material technology exploits the damping capabilities of viscoelastic material (VEM) embedded into the host structure. The VEM layer damping treatment is modeled by using the Golla-Hughes-McTavish (GHM) method, which is employed to account for the frequency-dependent characteristics of the VEM. The case of VEM spread over the entire span of the structure is considered. The displayed numerical results provide a comprehensive picture of the synergistic implications of both techniques, namely, the tailoring and damping technology on the dynamic response of a rotating thin-walled b ε am exposed to external time-dependent excitations.

• Journal of the Korean Society of Hazard Mitigation
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• v.9 no.1
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• pp.81-89
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• 2009

Until now, Korea carried out disaster management under the perception that the central government or the local government bodies are totally responsible. However as the size of disasters become larger, the capacity of the public disaster management did not live up to the expectations. To analyze this issue, this research conducted interviews on disaster response readiness by "individual resident-residents cooperation-public/private collaboration" according to each preparedness-response-recovery stage, as resident representatives (Head of Ri, Head of Tong) as subjects. Based on the interviews, surveys were conducted to deduct the necessary factors needed for the general residents to exhibit disaster prevention capabilities. The surveys consist of 6 factors-risk perception, evacuation inductively, individual evacuation response, disaster prevention system, lookout & precaution, information communication.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.1
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• pp.48-53
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• 2013

Polynomial response surface model has been widely used as approximation model which replace physical or numerical experiments in various engineering fields. Generally, low-order model is used to reduce experimental points required to construct the response surfaces, but this approach has limit to represent the highly non-linear phenomena. In this paper, we developed the method to expand modeling capabilities of polynomial response surfaces by increasing order of polynomial and selecting optimum polynomial basis functions. Genetic algorithm is used to choose optimal polynomial basis functions. Developed method was applied to analytic functions with 1 or 2 variables and wind tunnel test data modeling. The results show that this method is applicable to building response surface models for highly non-linear phenomena.

• Smart Structures and Systems
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• v.6 no.5_6
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• pp.579-593
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• 2010

Low-power radio frequency (RF) chip transceiver technology and the associated structural health monitoring platforms have matured recently to enable high-rate, lossless transmission of measurement data across large-scale sensor networks. The intrinsic value of these advanced capabilities is the allowance for high-quality, rapid operational modal analysis of in-service structures using distributed accelerometers to experimentally characterize the dynamic response. From the analysis afforded through these dynamic data sets, structural identification techniques can then be utilized to develop a well calibrated finite element (FE) model of the structure for baseline development, extended analytical structural evaluation, and load response assessment. This paper presents a case study in which operational modal analysis is performed on a three-span prestressed reinforced concrete bridge using a wireless sensor network. The low-power wireless platform deployed supported a high-rate, lossless transmission protocol enabling real-time remote acquisition of the vibration response as recorded by twenty-nine accelerometers at a 256 Sps sampling rate. Several instrumentation layouts were utilized to assess the global multi-span response using a stationary sensor array as well as the spatially refined response of a single span using roving sensors and reference-based techniques. Subsequent structural identification using FE modeling and iterative updating through comparison with the experimental analysis is then documented to demonstrate the inherent value in dynamic response measurement across structural systems using high-rate wireless sensor networks.

• Journal of the Society of Disaster Information
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• v.19 no.3
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• pp.451-470
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• 2023

Purpose: Since COVID-19 was first discovered in China in December 2019, it has rapidly spread around the world, causing serious economic and social problems not only in individuals' lives, but also in businesses and countries. Individuals, businesses, and governments have all made various efforts to prevent the spread of COVID-19. Although the roles of individuals, companies, and the government are important to respond to and manage infectious diseases, previous studies have only partially studied the roles. Therefore, in this study, the roles of individuals, companies, and the government to achieve results in responding to infectious diseases disaster management A comprehensive study was conducted on this issue, and it was attempted to understand the impact of workers' perceptions of infectious disease disaster management and government and corporate capabil]ities on disaster response performance. Method: The survey was conducted for workers in the automobile manufacturing industry in Ulsan, Gyeongju, and Yangsan, and frequency analysis, factor analysis, correlation analysis, and regression analysis were performed. Result: It was found that worker perception had a positive effect on both government and corporate capabilities as well as disaster management performance. In addition, government capacity and corporate capacity had a positive effect on disaster management performance. Conclusion: The results of this study are meaningful in that they reveal that not only workers' perceptions but also the capabilities of the government and companies are important to achieve disaster response performance. In addition, workers should make good use of opportunities for education and participation provided by the government and corporations, and make the most social efforts that workers can make.

• Journal of the Korean Society of Safety
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• v.28 no.1
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• pp.158-163
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• 2013

While job stress evaluations are reported in the recent surveys upon the nuclear power plants(NPPs), any significant advance in the types of questionnaires is not currently found. There are limitations to their usefulness as analytic tools for the management of safety resources in NPPs. Data mining(DM) has emerged as one of the key features for data computing and analysis to conduct a survey analysis. There are still limitations to its capability such as dimensionality associated with many survey questions and quality of information. Even though some survey methods may have significant advantages, often these methods do not provide enough evidence of causal relationships and the statistical inferences among a large number of input factors and responses. In order to address these limitations on the data computing and analysis capabilities, we propose an advanced procedure of survey analysis incorporating the DM method into a statistical analysis. The DM method can reduce dimensionality of risk factors, but DM method may not discuss the robustness of solutions, either by considering data preprocesses for outliers and missing values, or by considering uncontrollable noise factors. We propose three steps to address these limitations. The first step shows data mining with response surface method(RSM), to deal with specific situations by creating a new method called response surface data mining(RSDM). The second step follows the RSDM with detailed statistical relationships between the risk factors and the response of interest, and shows the demonstration the proposed RSDM can effectively find significant physical, psycho-social, and environmental risk factors by reducing the dimensionality with the process providing detailed statistical inferences. The final step suggest a robust stress management system which effectively manage job stress of the workers in NPPs as a part of a safety resource management using the surrogate variable concept.

• Journal of Digital Convergence
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• v.18 no.9
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• pp.191-198
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• 2020

In this study, in order to propose an improvement plan for fire simulation training to improve fire response capability, fire simulation training is conducted for three business facilities, and changes according to whether training materials are used and whether the response time for each response stage is reflected in the training evaluation. The response posture and response ability of the training participants were observed and analyzed. As a result of the analysis, it was analyzed that most of the training participants improved their participation in training, response posture, and response ability when the use of training textbooks and response time for each response stage were reflected in the training evaluation. In the event of a fire simulation training, a number of training materials that can similarly implement the fire situation are used to improve and maintain the fire response capabilities (fire notification and fire report, initial extinguishing, and evacuation) of the training participants, and the target time for each response step. The result was that it can be used as a useful index for improving fire response capability and improving fire simulation training in the future and feedback only when quantitative training evaluation is conducted based on this setting.