• Advances in concrete construction
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• 제15권6호
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• pp.391-404
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• 2023

In this study, the modeling of the transverse connection of fully precast steel-UHPC (Ultra-High-Performance Concrete) lightweight composite bridges were conducted. The transverse connection between precast components plays a critical role in the overall performance and safety of the bridge. To achieve an accurate and reliable simulation of the interface behavior, the cohesive model in ABAQUS was employed, considering both bending-tension and compression-shear behaviors. The parameters of the cohesive model are obtained through interface bending and oblique shear tests on UHPC samples with different surface roughness. By validating the numerical simulation against actual joint tests, the effectiveness and accuracy of the proposed model in capturing the interface behavior of the fully precast steel-UHPC lightweight composite bridge were demonstrated.

• 국제학술발표논문집
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• The 3th International Conference on Construction Engineering and Project Management
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• pp.658-668
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• 2009

Earth-moving operation has a great impact on the overall budget and schedule of any heavy civil projects. More often than not, the operational decisions are made largely based on field personnel's experience and judgment. In particular, decisions on earth moving operations by scraper-dozer fleets have been heavily influenced by the following belief: "The longer a dozer pushes a scraper for loading, the better earth-moving productivity is gained by the fleet." Even though there is some truth to this notion, scraper-dozer earth moving operations involve a much complex process that requires a systematic analysis for predicting the maximum production. To this end, this paper presents a spreadsheet-based scraper-dozer fleet operation model for its production optimization. Various optimization techniques, including a genetic-algorithm method, are presented for comparison and each technique's pros and cons are discussed.

• 환경영향평가
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• 제10권4호
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• pp.319-326
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• 2001

This study is aimed at the development of a comprehensive web-based partial differential equation solver (WPDES) using multidimensional finite element method, which can be operated on the basis of world wide web. Overall issues of engineering and environmental information management and facility control could be implemented using this solver. This paper describes the development technique of the model, which is first part on development of partial differential equation solver. Conventional commercial general solver of computational fluid dynamics problems were investigated. All the relevant environmental models were analyzed to develop integrated environmental management system using WPDES. The governing equations and the parameters of investigated models were analyzed and integrated. Several numerical modules were invented for each partial differential term in partial differential equation of many related modeling problems. Each module was coded in the fashion of object oriented method, and was combined independently for the overall governing equation. WPDES has unique characteristic, which can analyze the problem through the suitable combination of modules without development of additional models for each environment problem with different governing equation, main variables, and parameters.

• 기술혁신연구
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• 제9권1호
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• pp.1-19
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• 2001

Importance of technology evaluation cannot be overemphasized to support the effective investment policy. Most of the technology evaluation relies on either quantitative analysis for the value or qualitative comparison due to some attribute. When qualitative comparison is made, typically not only individual attribute. but also overall score is evaluated by the committee of experts. In this paper, we consider the qualitative evaluation procedure used in a venture incubating center and validate if the relationship between the average score of individual attribute and the overall score is significant. Additionally, we identify if the initially evaluated scores are good indicators for the realized future value of technology. Structural equation modeling approach is used and we expect that our approach can make important contributions on improving the currently used technology evaluation method.

• Journal of Sport and Applied Science
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• 제8권1호
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• pp.1-10
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• 2024

The purpose of this study was to examine the structural relationship among organizational justice, athlete satisfaction, team commitment, and organizational citizenship behavior toward college athletes. To achieve this purpose, this study employed a convenience sampling method via a questionnaire dissemination. A total of 285 responses were collected from college athletes. Among those, 21 responses were excluded as they were not completed, leaving 264 usable data. The data was computed in SPSS 28.0 and AMOS 28.0, and analyzed with correlation analysis, reliability analysis, confirmatory factor analysis, and structural equation modeling analysis. Overall, organizational justice had a positive influence on athlete satisfaction, team commitment, and organizational citizenship behavior. Athlete satisfaction had a positive influence on team commitment and organizational citizenship behavior. However, there was no relationship between team commitment and organizational citizenship behavior. These findings provided empirical foundational data on the impact of organizational justice on psychological and behavioral outcomes and the overall efficiency and effectiveness of organizations, with a focus on college athletes who played a central role in the context of college sports setting.

• KCI Concrete Journal
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• 제11권3호
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• pp.115-126
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• 1999

An analytical method based on the nonlinear layered finite element method is developed to simulate an overall load-deflection behavior of strengthened beams. The developed model distinguishes itself by its capability to trace residual flexural behavior of a beam after the fracture of brittle strengthening materials at peak load. The model. which uses a rather advanced numerical technique for iterative convergence to equilibrium, can be regarded as superior to the two models based on load control and displacement control The model predictions were compared with the experimental results and it was observed that there was good agreement between them.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제5B권3호
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• pp.267-271
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• 2005

This paper deals with two kinds of novel shape switched reluctance motors (SRM) with magnetic barriers in order to improve operating performances of prototype. The magnetic barriers make rotor poles more saturated, and consequently inductance profiles are distorted. The changed inductance affects input current shape and eventually torque characteristics. In order to analyze the complicated flux pattern of the SRM with magnetic barriers and its terminal characteristics simultaneously, coupled field circuit modeling method is used. The finite element method is used to model the nonlinear magnetic field, and coupled to the circuit model of the SRM overall system. After experimental results are presented to prove the accuracy of the method, the several analysis results are compared, and the improved rotor shape is presented.

• 한국소음진동공학회논문집
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• 제18권9호
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• pp.952-960
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• 2008

Fan noise prediction method is presented for air conditioning, automobile and electronic cooling system applications where fan acts as an internal equipment having very complicated flow interaction with other various system components. The internal flow paths and distribution in the fan-applied systems such as computer or air conditioner are analyzed by using the FNM(flow network modeling). Fan noise prediction method comprises two models for the discrete frequency noise due to rotating steady aerodynamic lift and blade interaction and for the broadband noise due to turbulent boundary layer and wake vortex shedding. Based on the fan operation point predicted from the FNM analysis results and fan design parameters, the present far noise model predicts overall sound pressure level and spectrum. The predictions for the flow distribution, the fan operation and the noise level in air cooling system by the present method are well agreed with 3-D CFD and actual noise test results.

• 전기학회논문지
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• 제65권11호
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• pp.1907-1912
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• 2016

In fact, in order to obtain good performances and low torque ripple, a high-resolution sensor is needed, which is costly and usually needs a special construction for the machine. So researchers are becoming aware of their cost and are exploring the possibility of cost reduction. Information of rotor position is necessary to drive Linear Switched Reluctance Motor(LSRM). Therefore, linear optical encoder is used to detect a mover position. Normally, since the price of encoder, which is used for linear motor is relatively higher than the one used for rotory motor and the cost of additional equipment increases with the length of motor. This is not always appropriate, considering economical efficiency in case of using the linear optical encoder. As a results, LSRM has a great part for the total cost. Therefore, in this paper, we propose LSRM position detecting modeling with reflective type photo-sensor. Additionally, we have investigated the possibility of the reduced position sensor for LSRM drives with advanced control technique. To certify the overall characteristics of the proposed method, a simulation using PSIM software has been carried out and the informative results are displayed.

• 한국산학기술학회논문지
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• 제15권2호
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• pp.1027-1035
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• 2014

휴대용 기기에서 가장 중요한 설계 요소는 소비 전력이다. 본 논문에서는 휴대용 온습도 측정기 설계 초기에 전력 소비 모델을 제시하고, 제시된 모델에 입각해 휴대용 온습도 측정기의 소비 전력을 설계한다. 이렇게 설계된 휴대용 온습도 측정기의 소비 전력을 사전 검증함으로써 제품 구현 전에 설계 검증을 완료하기 위한 전력 소비 설계 모델링 방안을 제시하고자 한다. 한편, 대기 모드에서 소비 전류를 효과적으로 감소시키기 위한 전력 소비 설계 개선 방안도 제시한다. 휴대용 온습도 측정기 구현을 통해 전력 소비 모델링에 입각한 설계 방법론의 타당성을 확인할 것이다.