• Nuclear Engineering and Technology
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• v.54 no.6
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• pp.2107-2119
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• 2022

Accurate remaining useful life (RUL) prediction for critical components of nuclear power equipment is an important way to realize aging management of nuclear power equipment. The electric gate valve is one of the most safety-critical and widely distributed mechanical equipment in nuclear power installations. However, the electric gate valve's extended service in nuclear installations causes aging and degradation induced by crack propagation and leakages. Hence, it is necessary to develop a robust RUL prediction method to evaluate its operating state. Although the particle filter(PF) algorithm and its variants can deal with this nonlinear problem effectively, they suffer from severe particle degeneracy and depletion, which leads to its sub-optimal performance. In this study, we combined the whale algorithm with regularized particle filtering(RPF) to rationalize the particle distribution before resampling, so as to solve the problem of particle degradation, and for valve RUL prediction. The valve's crack propagation is studied using the RPF approach, which takes the Paris Law as a condition function. The crack growth is observed and updated using the root-mean-square (RMS) signal collected from the acoustic emission sensor. At the same time, the proposed method is compared with other optimization algorithms, such as particle swarm optimization algorithm, and verified by the realistic valve aging experimental data. The conclusion shows that the proposed method can effectively predict and analyze the typical valve degradation patterns.

• Journal of the Korean Operations Research and Management Science Society
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• v.34 no.3
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• pp.85-104
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• 2009

Managers have come to realized that a large and increasing amount of sources for a corporate competitive advantage can be found in their company's supply chain. At a fundamental level, there is a similar consensus that building a collaborative supply management is a more effective way of managing firms' supply chains. This paper is an attempt to examine the effects of collaborative supply management by probing a mechanism which shows how competences and/or performance are transferred from suppliers to markets through the supply chains. Research hypotheses regarding the relationships between collaborative supply management, supplier Performance, buyer internal performance (new product development and operational performance), and buyer market performance were empirically validated by utilizing a structural equation modeling analysis. The research result Indicates the positive impacts of a collaborative supply chain on supply performance as well as buyer internal and market performance, which also well illustrate how the improved competence and/or performance of suppliers engendered from the supplier-buyer collaboration flows throughout the entire supply chain.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.11
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• pp.1021-1031
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• 2020

This study aims to invest in empirical relationships in a model that becomes the process of Team-Performance due to participation in practical training through causality between Training Effectiveness variables, soft-skill competence, Employee-Creativity, and team performance. This study uses a quantitative approach. The analytical tool used is structural equation modeling (SEM) using AMOS version 23 software. Accidental sampling technique is used to collect the sample. As many as 202 respondents filled up a survey questionnaire with complete and valid answers. This study's results significantly contribute to fill the gap of inadequate empirical evidence that can answer critical questions about the missing link between training and employee-performance, more specifically between training-effectiveness and team-performance. The results showed that practical training would encourage employees' soft-skill competence, improve Employee-Creativity, and improve Team-Performance. Furthermore, training-effectiveness also plays a significant role in enhancing employee-creativity and helping in optimal team-performance. This study also found that the relationship between employee-creativity and team-performance did not show positive and significant results; therefore, empirically, it did not support the hypothesis built in this study. Practical training targeted towards increasing soft-skills and creativity is a fundamental reason which not only aims to contribute toward organizational performance but also provides personal feedback for self-development.

• Earthquakes and Structures
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• v.15 no.1
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• pp.9-17
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• 2018

This paper provides recommendations for setting performance requirements for the seismic design of building structures in Hong Kong. Fundamental issues relating to the required level of structural safety will be addressed, which is then followed with a recommended seismic action model for structural design purposes in Hong Kong. The choice of suitable performance criteria of structures and the return period of the design seismic actions are first discussed. The development of the seismic hazard model for Hong Kong is then reviewed. The determination of the design response spectrum and the choice of design parameters for structures of different importance classes will also be presented.

• Journal of Magnetics
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• v.21 no.3
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• pp.399-404
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• 2016

This paper presents a new permanent magnet (PM) assisted topology for a recently introduced brushless wound rotor synchronous machine (BL-WRSM) [1]. The BL-WRSM had a dual-inverter configuration for generating a composite magneto motive force (MMF) with a fundamental component and a subharmonic component. The subharmonic component of the MMF is used for brushless excitation of the rotor. In this paper, additional PMs were introduced on the rotor of the BL-WRSM, making it a hybrid BL-WRSM. We also discussed the flux weakening operation for the hybrid BL-WRSM. The hybrid BL-WRSM offered advantages for starting the machine and provided better performance under full-load conditions. The finite element method (FEM) was used to analyze the performance of the hybrid BL-WRSM, and we compared its performance with BL-WRSM. Finally, prototypes were built with and without the PM-assistance, and experiments were conducted to demonstrate their performance.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2004.10a
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• pp.3-10
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• 2004

The earthquake-resistant structural systems have to ensure the sufficient stiffness and ductility for the stability. For those purposes, recently, the performance design concept to increase the degree of absorbed energy level of structures has been proposed. One practical way of the performance design in the spatial structures is to apply the isolation system to boundary parts of roof system and sub-structure to obtain the target performance. So, it is necessary to examine the characteristics of dynamic behavior of spatial structures governed by higher modes rather than lower modes different from the cases of high rise buildings. The objectives of this paper are to develop the equivalent lumped mass model to simplify the analytical processes and to investigate the dynamic behavior of roof system according to the mass and the stiffness of sub-structures as a fundamental study of performance design for the spatial structures.

• KIEAE Journal
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• v.4 no.3
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• pp.27-35
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• 2004

The conventional way to acquire sufficient amount of daylight in interiors is to provide large openings with clear glass. The use of clear glass on the whole facade, however, might cause a sort of visual problem because of the harness of direct sun and brighter sky surface than expected. They should be filtered in opticalway or bounced in the architectural. One of the common solutions for the problem might be the use of photometric glasses with various transmittances for the glass walls. This paper deals with performance data related to the impact of various transmittal glazing materials for window systems in terms of daylighting. A series of scale model measurements was carried out with the fundamental configuration of a commonly used all-glass facades. Additionally some experimental performance index was issued for the better expression of the need of natural lighting.

• Journal of the Korean Recycled Construction Resources Institute
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• v.1 no.3
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• pp.163-172
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• 2013

This paper presents a comprehensive review of recent advances in ultra-high performance concrete (UHPC). Fundamental characteristics of UHPC are elaborated with focus on its material constituents, mixing, and formulation procedures. Use of state-of-the-art materials such as carbon nanotubes or nano-silica is discussed as well, whose inclusion may enhance the performance of UHPC. The review evaluates supplementary treatment methods (e.g., pressuring curing) and identifies applicable standard test methods for determining the properties and behavior of UHPC. Site implementation is provided to link laboratory research with full-scale application. Research needs are suggested to further develop UHPC technologies from technical and socio-economical perspectives.

• Journal of Korea Multimedia Society
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• v.17 no.4
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• pp.441-457
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• 2014

Observed from the recent performance evaluation of clustering schemes in wireless sensor networks, we found that most of them did not consider various sensor characteristics and its application environment. Without considering these, the performance evaluation results are difficult to be trusted because these networks are application-specific. In this paper, for the fair evaluation, we measured several clustering scheme's performance variations in accordance with sensor data pattern, number of sensors per node, density of points of interest (data density) and sensor coverage. According to the experiment result, we can conclude that clustering methods are easily influenced by POI variation. Network lifetime and data accuracy are also slightly influenced by sensor coverage and number of sensors. Therefore, in the case of the clustering scheme that did not consider various conditions, fair evaluation cannot be expected.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.10a
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• pp.35-36
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• 2016

Recently, with the increasing demand of high performance of concrete, the mix design of concrete mixture has became low water-to-binder ratio with high binder content. To compensate these trend of mix design, high range water reducer, or superplascizier has been invented to achieve high flowable concrete. Although this superplasticizer provides favorable workability based on its dispersing action on the components of concrete mixture, it has an limitation of decreasing viscosity of the mixture, and thus it is difficult to secure sufficient workability for high performance concrete mixtures with high binder content. To improve the workability of concrete with high viscosity, recently, low-viscosity type superplasticizer was introduced, and in this research, a fundamental properties of low-viscosity type superplasticizer is evaluated.