• Smart Structures and Systems
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• v.23 no.2
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• pp.107-122
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• 2019

As one of the most important parameters in structural health monitoring, structural frequency has many advantages, such as convenient to be measured, high precision, and insensitive to noise. In addition, frequency-change-ratio based method had been validated to have the ability to identify the damage occurrence and location. However, building a precise enough finite elemental model (FEM) for the test structure is still a huge challenge for this frequency-change-ratio based damage detection technique. In order to overcome this disadvantage and extend the application for frequencies in structural health monitoring area, a novel method was developed in this paper by combining the cross-model cross-mode (CMCM) model updating algorithm with the frequency-change-ratio based method. At first, assuming the physical parameters, including the element mass and stiffness, of the test structure had been known with a certain value, then an initial to-be-updated model with these assumed parameters was constructed according to the typical mass and stiffness distribution characteristic of shear buildings. After that, this to-be-updated model was updated using CMCM algorithm by combining with the measured frequencies of the actual structure when no damage was introduced. Thus, this updated model was regarded as a representation of the FEM model of actual structure, because their modal information were almost the same. Finally, based on this updated model, the frequency-change-ratio based method can be further proceed to realize the damage detection and localization. In order to verify the effectiveness of the developed method, a four-level shear building was numerically simulated and two actual shear structures, including a three-level shear model and an eight-story frame, were experimentally test in laboratory, and all the test results demonstrate that the developed method can identify the structural damage occurrence and location effectively, even only very limited modal frequencies of the test structure were provided.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.9
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• pp.3194-3210
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• 2022

Wall obstruction is the main factor leading to the non-line of sight (NLoS) error of indoor localization based on received signal strength indicator (RSSI). Modeling and correcting the path loss of the signals through the wall will improve the accuracy of RSSI localization. Based on electromagnetic wave propagation theory, the reflection and transmission process of wireless signals propagation through the wall is analyzed. The path loss of signals through wall is deduced based on power loss and RSSI definition, and the theoretical model of path loss of signals through wall is proposed. In view of electromagnetic characteristic parameters of the theoretical model usually cannot be accurately obtained, the statistical model of NLoS error caused by the signals through the wall is presented based on the log-distance path loss model to solve the parameters. Combining the statistical model and theoretical model, a hybrid model of path loss of signals through wall is proposed. Based on the empirical values of electromagnetic characteristic parameters of the concrete wall, the effect of each electromagnetic characteristic parameters on path loss is analyzed, and the theoretical model of regional path loss of signals through the wall is established. The statistical model and hybrid model of regional path loss of signals through wall are established by RSSI observation experiments, respectively. The hybrid model can solve the problem of path loss when the material of wall is unknown. The results show that the hybrid model can better express the actual trend of the regional path loss and maintain the pass loss continuity of adjacent areas. The validity of the hybrid model is verified by inverse computation of the RSSI of the extended region, and the calculated RSSI is basically consistent with the measured RSSI. The hybrid model can be used to forecast regional path loss of signals through the wall.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1289-1294
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• 2003

This paper proposes a novel and efficient intelligent digital redesign technique for a Takagi-Sugeno (TS) fuzzy system. The term of intelligent digital redesign involves converting an existing analog fuzzy-model-based controller into an equivalent digital counterpart in the sense of state matching. In this paper, we suggest the discretization method based on the dual-rate sampling approximation is first proposed, and then attempt to globally match the states of the overall closed-loop TS fuzzy system with the pre-designed analog fuzzy-model-based controller and those with the digitally redesigned fuzzy-model-based controller. To show the feasibility and the effectiveness of the proposed method, a computer simulation is provided.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2004.04a
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• pp.25-32
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• 2004

In this proposed work new finite element model for multi-delaminated plates is proposed. In the current analysis procedures of multi-delaminated plates, plate element based on Mindlin plate theory is used in order to obtain accurate results of out-of-plane displacement of thick plate. And for delaminated region, plate element based on Kirchhoff plate theory is considered. To satisfy the displacement continuity conditions, displacement vector based on Kirchhoff theory is transformed to displacement of transition element. The numerical results show that the effect of delaminations on the modal parameters of delaminated composites plates is dependent not only on the size, the location and the number of the delaminations but also on the mode number and boundary conditions. Kirchhoff based model have higher natural frequency than Mindlin based model and natural frequency of the presented model is closed to Mindlin based model.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2003.09b
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• pp.129-132
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• 2003

This paper proposes a novel and efficient intelligent digital redesign technique for a Takagi-Sugeno (TS) fuzzy system. The term of intelligent digital redesign involves converting an existing analog fuzzy-model-based controller into an equivalent digital counterpart in the sense of state matching. In this paper, we suggest the discretization method based on the dual-rate sampling approximation is first proposed, and then attempt to globally match the states of the overall closed-loop TS fuzzy system with the pre-designed analog fuzzy-model-based controller and those with the digitally redesigned fuzzy-model-based controller. To show the feasibility and the effectiveness of the proposed method, a computer simulation is provided.

• Journal of Korean Library and Information Science Society
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• v.34 no.3
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• pp.317-343
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• 2003

The purpose of this study is to develop a general model for web-based children's literature education and to validate the model. Both qualitative and quantitative methods were used for the analysis of this study. The findings of this research were three point. At First, the model of web-based children's literature education have five major components i.e., objects, construction of activity, display of activity, management of it, and evaluation of it. At second, the creative writing was revealed the core of the web-based children's education. The third, web-based children's literature activity can be followed by cyber learning community activities.

• Journal of Digital Convergence
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• v.7 no.4
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• pp.43-56
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• 2009

The concept causing all the fuss is "the utility computing or the usage-based IT service", which now represents the future for IT asset in all aspects of the way they work in business, the commercial and public sector. The core of "utility computing or usage-based IT service" is changing the IT assert from "ownership" to "borrowing", which enables managers to get greater utilization of data-centre resources at lower operating costs. This trend is spreaded in public sector centering the Governmental Internet data Center of Korea(NCIA). So, it has need to make an usage-based IT service model that is suitable for public sector. In this paper, we propose the usage-based IT service model that is composed of IT service framework, service pricing model and IT service architecture.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 1999.11a
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• pp.53-58
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• 1999

Recently, the size and complexity of the system we have to develop and to deal with are expanding quickly. Because of the great size of causally related network in itself, such a system will be very difficult to deal with based on the typical reduction model. One of alternatives for this is to adopt emergence-based paradigm instead of reduction-based paradigm. The first is based on the low level causality and the latter on the high level emergence. In this paper we proposed an emergence-based object model realizable in terms of engineering. It is the abstracted one from original object model using of such concepts as performance function, interest function and emotional layer. The suggested model allows us to emerge some important concepts which might be useful for implementing the complex system which can hardly be available by reduction paradigm.

• International journal of advanced smart convergence
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• v.12 no.3
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• pp.141-148
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• 2023

As the direction of education in the fourth industry in the 21st century, convergence talent education that emphasizes the connection and convergence between core competency-based education and academia is emerging to foster creative talent. The purpose of this paper is to present the criteria for evaluating the competency of learning outcomes in order to develop a strategic model for innovation in engineering teaching-learning. In this paper, as a study to establish the direction of implementation of convergence talent education, a creative innovation teaching method support system was established to improve the quality of convergence talent education. Firstly, a plan to develop a teaching-learning model based on computing thinking. Secondly, it presented the development of a teaching-learning model based on linkage and convergence learning. Thirdly, we would like to present educational appropriateness and ease based on convergence learning in connection with curriculum improvement strategies based on computing thinking skills. Finally, we would like to present a strategic model development plan for innovation in engineering teaching-learning that applies the convergence talent education program.

• Journal of the Korean Home Economics Association
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• v.29 no.2
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• pp.241-248
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• 1991

The aim of this study is to propose the criteria for a evaluation model of the lifetime household work and organize the model. The results were as follows: Three criteria for a evaluation model of the life-time household work were proposed. $\circled1$ An appropriate framework of the evaluation model should be based on the transition of the family life. $\circled2$ The model should include major variables influencing the value of household work of homemaker. $\circled3$ The model should be flexible enough to accommodate various evaluation methods, and should reflect idiosyncracies of different evaluation methods. In view of the criteria stated above, the present study is based on the family life cycle framework. And the age of the last offspring exhibits a consistent major influence in the evaluation based on the household work hours, while the education level of homemakers shows a consistent major influence in the evaluation based on household worker. So as to reflect these two major variables in the family life cycle framework.