• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.10
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• pp.185-190
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• 2007

In this paper, minimum sampling rates and method of nonlinear characterization were suggested for low power, quasi-memoryless PAs. So far, the Nyquist rate of the input signal has been used for nonlinear PA modeling, and it is burdening Analog-to-digital converters for wideband signals. This paper shows that the input Nyquist rate sampling is not a necessary condition for successful modeling of quasi-memoryless PAs. Since this sampling requirement relives the bandwidth requirements for Analog-to-digital converters (ADCs) for feedback paths in digital pre-distortion systems, relatively low-cost ADcs can be used to identify nonlinear PAs for wideband signal transmission, even at severe aliasing conditions. Simulation results show that a generic memoryless nonlinear RF power amplifier with AMAM and AMPM distortion can be successfully identified at any sampling rates. Measurement results show the modeling error variation is less than 0.8dB over any sampling rates.

• Journal of the Korea institute for structural maintenance and inspection
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• v.13 no.2 s.54
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• pp.172-180
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• 2009

Normally in order to build a semi-active control system equipped with MR damper, the dynamic modeling of the damper is required to numerically predict its dynamic damping force and also its behavioral characteristics. For the dynamic modeling of the MR damper, this paper attempts to predict and evaluate its dynamic behavior by applying specifically both a power model and a Bingham model. Dynamic loading tests were performed on the squeeze type of damper specially designed for this research, and force-displacement hysteresis loops confirmed the effectiveness of the damper as a semi-active control device. In the meantime, in order to evaluate the effectiveness of each model applied, the model parameter for each model was identified. On the basis of the parameter, we derived the error ratio of the force-velocity relationship curve and the dynamic damping force, which was contrasted and compared with the experimental results of the squeeze type of damper. Finally, the squeeze type of MR damper developed in this research was proved to be valid as a semi-active control device, and also the evaluation of the two dynamic models showed they were working fine so that they were likely to be easily utilized to numerically predict the dynamic characteristics of any dampers with MR fluid as well as the squeeze type of MR damper.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.1_2
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• pp.15-34
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• 2006

This paper introduces an empirical modeling technique. This technique uses a set of sample results which are collected from a few small scale simulations. Empirical models are developed by applying a couple of statistical estimation techniques to these samples. We built two types of models for cache miss rates in Symmetric Multiprocessor systems. One is for the changes of input data set size while the specification of target system is fixed. The other is for the changes of the number of processors in target system while the input data set size is fixed. To develop accurate models, we built individual model for every kind of cache misses for each shared data structure in a program. The final model is then obtained by integrating them. Besides, combined use of Least Mean Squares and Robust Estimations enhances the quality of models by minimizing the distortion due to outliers. Empirical modeling technique produces extremely accurate models without analysis on sample data. In addition, since only snail scale simulations are necessary, once a set of samples can be collected, empirical method can be adopted in any research areas. In 17 cases among 24 trials, empirical models present extremely low prediction errors below $1\%$. In the remaining cases, the accuracy is excellent, as well. The models sustain high quality even when the behavioral characteristics of programs are irregular and the number of samples are barely enough.

• Journal of Mechanical Science and Technology
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• v.15 no.4
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• pp.448-458
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• 2001

The primary goal of virtual prototyping is to eliminate the need for fabricating physical prototypes, and to reduce cost and time for developing new products. A virtual prototyping seeks to create a virtual environment where the development of a new model can be flexible as well as rapid, and experiments can be carried out effectively concerning kinematics, dynamics, and control aspects of the model. This paper addresses the virtual environment used for virtual prototyping of a passenger vehicle. It has been developed using the dVISE environment that provides such useful features as actions, events, sounds, and light features. A vehicle model including features, and behaviors is constructed by employing an object-oriented paradigm and contains detailed information about a real-size vehicle. The human model is also implemented not only for visual and reach evaluations of the developed vehicle model, but also for behavioral visualization during a crash test. For the real time driving simulation, a neural network model is incorporated into the virtual environment. The cases of passing bumps with a vehicle are discussed in order to demonstrate the applicability of a set of developed models.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.12
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• pp.1073-1087
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• 2020

The purpose of this paper is to (1) evaluate a proposed conceptual model based on integrated Technology Acceptance Model (TAM) and Corporate Social Responsibility (CSR); (2) compare the differences between Vietnam and South Korea regarding the effects of consumer perception of CSR activities and technology acceptance on intention to adopt mobile banking. Structural Equation Modeling (SEM) was conducted to analyze the data collected from the field survey questionnaires administered to a convenience sample of Vietnamese and Korean banking customers. The results showed that there is a difference between South Korea and Vietnam with regard to intention to use mobile banking services. While the effects of social responsibility and environmental responsibility on trust, trust on perceived usefulness, perceived risk on intention to use, perceived usefulness on intention to use were significant in the context of Vietnam but those effects were not significant in South Korea. Therefore, this study has attempted to fill this gap by empirically examining some of the important factors influencing the adoption of m-banking from the Vietnamese and Korean customers' perspectives. Finally, practical and theoretical implications for both banks and researchers in the m- banking context are also discussed in the concluding section.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.6
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• pp.399-407
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• 2020

The paper examines social entrepreneurial intention through outcome expectations. The proposed model incorporates outcome expectations from social cognitive career theory and theory of planned behaviors. The study also introduces a scale for outcome expectations in social entrepreneurship, including solving social problems, innovation, family tradition of social involvement, meaning in life, prestige and social recognition, competitive and favorite job and wealth. A survey of 279 students was conducted through face-to-face structured interviews. The confirm factor analysis and technique of structural equation modeling were used to explore relationships among latent constructs. Research results show that the outcomes impact only through three determinants of theory of planned behavior and do not have significant impact to social entrepreneurial intention. It suggests that outcome expectations may be a flexible factor. Individual outcome expectations can shift to motivations when facing favorable conditions such as family support, government support, etc. The findings suggest that the ability to predict social entrepreneurial intention of attitude toward behavior, subjective norms, and perceived behavioral control. The proposed model in this study contributes importantly to the emerging literature on entrepreneurial intention, particularly to social entrepreneurial intention. This study is also the first quantitative study to measure the impact of outcome expectations on social entrepreneurial intention.

• Journal of Families and Better Life
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• v.27 no.6
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• pp.21-29
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• 2009

This study investigated the effects of three factors-mothers' parenting beliefs; child care-home involvement; and the home learning environment - on the school readiness of 3- to 5-year-olds. The subjects were 366 children who were enrolled in child care centers located in Seoul and the Kyoungki area, and their mothers. The Structural Equation Modeling (SEM) technique was employed to test the pathways to children's school readiness as indicated by the child's abilities in vocabulary, math and reading. The results showed that mothers' stronger beliefs in their responsibilities in their children's academic and behavioral development predicted greater involvement in child care and better quality in the home learning environment. Likewise, the quality of the learning environment predicted the extent of the child's readiness for school. No direct relation was found between child care involvement and the child's school readiness. The results imply that multiple factors - parental, child-care-related, and home environmental- explain the extent to which the child is prepared to adjust to scholastic life.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.3
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• pp.167-175
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• 2020

The study aims to examine the relationships between service quality, experience value, relationship quality and behavior intentions. Validated measurements were identified from a literature review. The total of 309 valid respondents were used in this research. The measurement model and the conceptual model depicting hypothesized relationships were evaluated based on the 309 responses using confirmatory factor analysis and a structural equation modeling, accordingly. In addition, this study systematized the concepts, defined and tested the component scales of the relationship model between service quality, experience value, relationship quality and behavior intentions from the collected data, which helps to adequately identify the relationship between the factors in the model as well as the impact. The findings confirm that service quality influences experience values, relationship quality and purchase intention. Service quality, experience value, relationship quality and behavior intentions altogether are not well understood in current literature despite the important implication for managers, academicians and consumers alike. Contributes to a better fit between relationship marketing models and managerial practice in business markets. This study provides managerial implications regarding service quality and experience value so that firms and marketers can consult and apply. Managers should not only focus on the improvement of service quality but overall strategic planning.

• Journal of Korean Society of Steel Construction
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• v.12 no.1 s.44
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• pp.93-102
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• 2000

Substructuring-based hierarchical approach for design analysis and optimization of structural frames is presented in this study. The conceptual framework of this method is in the hierarchical modeling for design processes as well as structural systems and the methodology combining substructuring analysis and multilevel optimization. Mathematical models for analysis and synthesis are established on the common basis of substructuring systems. Modularized behavioral analysis, design sensitivity analysis and optimization are linked and integrated on the mathematical and structural basis of substructuring. Substructures are coordinated with the active constraints for system level and the weight ratio criteria. Numerical examples for test frames show the validity and effectiveness of the present approach.

• The Research Journal of the Costume Culture
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• v.28 no.1
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• pp.45-61
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• 2020

As consumers have transformed into the influential entities in the recent consumption environment, it needs a new concept to describe their characteristics. Drawn on the notion of smart consumer experience, this study views the multiple traits of new consumers as consumer smartness. Therefore, elaborating the concept of consumer smartness, this study aims to develop its measurement and validate it by examining the relationship with external variables. Two online surveys were conducted by a professional survey company that had nationwide consumer panels. A total of 531 adult consumers who had purchased fashion goods online completed a self-administered questionnaires. A series of exploratory and confirmative factor analysis generated 21 measuring items with six underlying constructs of consumer smartness such as innovativeness, opinion leadership, self-disclosure, marketing literacy, dissatisfaction, and technology sophistication. In order to validate the measurement, this study conducted a Pearson's correlation test and structural equation modeling analysis with consumer smartness and external constructs. The result shows that there was a significant positive relationship between consumer smartness and behavioral intentions online. In addition, consumer smartness influenced their shopping and sharing intention which supported the validity of new measurement of consumer smartness. This study provides a theoretical and empirical ground of understanding consumer smartness as new consumer characteristics in the changing environment of fashion retailing.