• Wind and Structures
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• 제26권3호
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• pp.129-146
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• 2018

Extreme wind speed analysis has been carried out conventionally by assuming the extreme series data is stationary. However, time-varying trends of the extreme wind speed series could be detected at many surface meteorological stations in China. Two main reasons, exposure change and climate change, were provided to explain the temporal trends of daily maximum wind speed and annual maximum wind speed series data, recorded at Hangzhou (China) meteorological station. After making a correction on wind speed series for time varying exposure, it is necessary to perform non-stationary statistical modeling on the corrected extreme wind speed data series in addition to the classical extreme value analysis. The generalized extreme value (GEV) distribution with time-dependent location and scale parameters was selected as a non-stationary model to describe the corrected extreme wind speed series. The obtained non-stationary extreme value models were then used to estimate the non-stationary extreme wind speed quantiles with various mean recurrence intervals (MRIs) considering changing climate, and compared to the corresponding stationary ones with various MRIs for the Hangzhou area in China. The results indicate that the non-stationary property or dependence of extreme wind speed data should be carefully evaluated and reflected in the determination of design wind speeds.

• Journal of Information Technology Applications and Management
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• 제23권1호
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• pp.97-117
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• 2016

Drawing on the theoretical framework of customer value-satisfaction-loyalty, this study examines how scarcity message influences customers' value, satisfaction, and loyalty in the context of group-buying social commerce. Previous studies have argued that scarcity message limiting the avilability of products and service is a source of enhancing customer value. In this regard, this study posits scarcity message as a predictor of customer value. Furthermore, this study classifies customer value into two forms (i.e., utilitarian value and hedonic value) and verfies how scarcity message is associated with them. To test the proposed research model and hypotheses, this study performed structural equation modeling (SEM) analyses, using a total of 292 data collected on users who have experience in purchasing products and service through group-buying social commerce sites such as Coupang, Timon, and WeMakePrice. The key results are as follows : First, scarcity message increases utilitarian and hedonic values and further customer satisfaction. Second, utilitarian value increases customer satisfaction and repurchase intention while hedonic value has nothing to do with them. The findings imply that customers seek to maximize utilitarian value through group-buying social commerce. Finally, this study indicates that repuchase intention depends greatly on customer satisfaction.

• 유통과학연구
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• 제18권10호
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• pp.25-38
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• 2020

Purpose: Traditional markets have served as important locations for social-cultural and economic activities. It is a hub of economic transactions and where people gather and exchange information and goods, while also serving as the center of social activities, including commercial exchanges. Accordingly, this study aimed to contribute to the studies on the perceived value in traditional markets for customers in different aspects. Research design, data, and methodology: To analyze the proposed model, data was collected from 456 respondents and analyzed with SPSS 21.0 and AMOS 21.0. The data was analyzed with structural equation modeling (SEM) using path analysis. Results: According to the results of the analysis, the perceived value comprises utilitarian value, emotional value, economic value, and social value, all of which had a positive impact on attitude. Emotional value and social value had a positive impact on subjective norms, while utilitarian value and economic value did not have an impact on subjective norms. Also, attitudes and subjective norms were found to have a positive impact on behavioral intention. Conclusions: Through this study, the value that the traditional markets need to provide to consumers have been identified. Traditional markets should develop into places that can provide value for their consumers.

• 한국자동차공학회논문집
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• 제11권5호
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• pp.163-169
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• 2003

Modeling of engine-generator system and its control responses are investigated using high performance generator controller. The nonlinear engine is modeled using mean torque production model based on experimental engine map. In case of diesel engine. the amount of injected fief is decided by engine controller depending on the APS(Acceleration Position Sensor) value. An electromechanical generator model contains electrical circuits and moment of inertia. The generator controller maximizes the performance of generator using decoupling and linearized current feedback control. The generator control system consists of 3-phase IGBT inverter and controller board based on 32 bit floating point DSP. Field oriented control algorithm with digital current feedback control at 10kHz sampling enabled high performance torque and speed control of induction machine. Not only the steady state but also the transient state responses can be evaluated through a batch test of the engine generator system. Developed engine and generator modeling and control can be utilized in various applications such as Series Hybrid Electric Vehicle(SHEV), engine-generator for emergency, and other hybrid generation systems.

• 한국BIM학회 논문집
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• 제2권2호
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• pp.37-45
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• 2012

부재를 표준화하여 설계 및 제작 생산성을 높이고 기계화 시공을 가능하게 하는 모듈러 교량이 건설 산업에서 중요하게 대두되고 있다. 반복성이 높고 설계, 제작 시공 과정에서의 정보의 원활한 전달이 필요하기 때문에 BIM(Building Information Modeling) 기술에 기반한 변수 모델링 정의를 제시하였다. 모듈러 교량이 갖는 변수 범위를 고려하여 고정변수, 변동변수, 연관변수로 구분하여 정의하고 이를 설계, 해석, 제작에 활용할 수 있도록 하였다. 구조시스템 개발과정의 지식을 정보화하여 3차원 모델의 정확성과 활용성을 높였다.

• 한국정보통신학회논문지
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• 제18권12호
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• pp.3069-3078
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• 2014

본 연구에서는 다양한 수중무기폭발 체계 중 대표적인 비닉(庇匿) 무기체계인 기뢰를 중심으로 공격형 부설에 의한 억제 시 적함 탐지의 핵심이 될 자력계를 신규 Modeling & Simulation에 의해 성능 개선의 효과를 사전 검증한다. 또한, 신규 3축 자력계를 설계/제작/실험을 진행한 결과를 다룬다. 신규 자력계를 새로운 신형 수중무기체계에 적용하기 위해 상용 전자기장 수치해석 도구를 이용해 잠수함을 모델링하여 실 함정의 자기장특성을 예측한다. 실험의 마지막 단계로 축소 모형을 제작하여 실제 해상시험을 하지 않더라도 육상에서 성능검증 할 수 있는 방법을 제시한다.

• Computers and Concrete
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• 제2권5호
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• pp.389-409
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• 2005

The Finite Element Analysis (FEA) is evidently a powerful tool for the analysis of structural concrete having nonlinearity and brittle failure properties. However, the result of FEA of structural concrete is sensitive to two modeling factors: the shear transfer coefficient (STC) for an open concrete crack and force convergence tolerance value (CONVTOL). Very limited work has been done to find the optimal FE Modeling (FEM) methodologies for structural concrete members strengthened with externally bonded FRP sheets. A total of 22 experimental deep beams with or without FRP flexure or/and shear strengthening systems are analyzed by nonlinear FEA using ANAYS program. For each experimental beams, an FE model with a total of 16 cases of modeling factor combinations are developed and analyzed to find the optimal FEM methodology. Two elements the SHELL63 and SOLID46 representing the material properties of FRP laminate are investigated and compared. The results of this research suggest that the optimal combination of modeling factor is STC of 0.25 and CONVTOL of 0.2. A SOLID 46 element representing the FRP strengthening system leads to better results than a SHELL 63 element does.

• Journal of Power Electronics
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• 제19권1호
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• pp.24-33
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• 2019

A new modeling method for AC-AC switched capacitor converters (SCCs) is introduced in this study. The proposed analytical method aims to accurately describe the input-output characteristics of AC-AC SCCs and establish a mathematical model for static voltage conversion ratio and equivalent resistance, which are key performance metrics for SCCs. A quantitative analysis of converter regulation capability is addressed on the basis of the modeling method. In this analysis, the effects of the control parameters and individual components on SCCs are illustrated extensively. Component stresses, such as the peak value and transient variation of the voltage/current of the converter, are also presented. The effectiveness of the proposed method is verified by comparing it with the existing modeling method and applying it to an AC-AC SCC with a conversion ratio of three. Two 1 kW prototypes are built in a laboratory, and their experimental results exhibit good agreement with the theoretical analysis.

• 전기전자학회논문지
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• 제24권4호
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• pp.1098-1103
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• 2020

본 논문은 리튬 이온 이차 전지의 전기적 실험 및 전기화학적 모델링을 통한 배터리 수명 상태(SOH)의 추정 방법을 다룬다. 배터리 전기적 노화 실험을 통하여 실제 배터리 수명 상태를 확인하기 위하여 전류 적산법을 사용한다. 전기적 실험에서 도출한 내부저항 값을 사용하여 SOH를 추정하며, 전기화학 모델링에서 사이클 수의 증가에 따른 SEI Layer의 변화를 통해 SOH를 추정한다. 실제 배터리 수명 상태를 포함한 세 가지 방법의 SOH 추정 방법에 가중치를 적용하여 새로운 SOH를 도출하며, 이는 전류적산법을 사용하여 구한 실제 값과의 오차를 줄여주어 추정 성능을 높인다.

• 융합경영연구
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• 제9권4호
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• pp.31-43
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• 2021

Purpose: This study investigated how consumption values influence consumers' purchasing decisions regarding environmentally friendly products. Based on the Consumption Values Theory, six dimensions of consumption values were defined: functional value-quality, functional value-price, emotional value, social value, conditional value, and epistemic value. In particular, the current study analyzed the differential impact of the environmentally friendly consumption values between two consumer groups - users and nonusers. By doing so, more effective marketing strategies can be applied to the target groups. Research design, data, and methodology: The online survey was conducted through Macromill Embrain in Korea to collect data from users vs. nonusers of environmentally friendly products. There were 215 usable responses in the users sample and 225 responses in the nonusers sample. Structural equation modeling (SEM) was performed by using AMOS 18.0. Results: The results revealed that four dimensions of consumption values, i.e., functional value-price, emotional value, conditional value, and epistemic value, positively influenced the users, while functional value-price and epistemic value positively influenced purchase intention toward environmentally friendly products among the nonusers. Conclusions: These results have important implications for applying effective marketing strategies for target consumers. Theoretical and practical implications are also discussed.