• Journal of Power Electronics
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• v.16 no.5
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• pp.1689-1697
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• 2016

Continuous conduction mode (CCM) boost converters are commonly used in home appliances and various industries because of their simple topology and low input current ripples. However, these converters suffer from several disadvantages, such as hard switching of the active switch and reverse recovery problems of the output diode. These disadvantages increase voltage stresses across the switch and output diode and thus contribute to switching losses and electromagnetic interference. A new topology is presented in this work to improve the switching characteristics of CCM boost converters. Zero-current turn-on and zero-voltage turn-off are achieved for the active switches. The reverse-recovery current is reduced by soft turning-off the output diode. In addition, an input current sensorless control is applied to the proposed topology by pre-calculating the duty cycles of the active switches. Power factor correction is thus achieved with less effort than that required in the traditional method. Simulation and experimental results verify the soft-switching characteristics of the proposed topology and the effectiveness of the proposed input current sensorless control.

• Journal of the Korean Society of Food Culture
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• v.32 no.5
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• pp.421-436
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• 2017

This study was conducted to examine the effects of Chinese perceptions of quality attributes on customer's satisfaction, revisit intention and recommendation intention for coffee shops in Beijing, China. Subjects of this study included 200 customers who had visited a coffee shop at least once during the last year. Statistical analyses were performed using SPSS v23.0 and AMOS v21.0. In this study, the majority of customers visited a coffee shop once or twice a week with friends. Respondents preferred tall-sized warm coffee in the store. The coffee shop quality attributes of were derived from five exploratory factors identified upon analysis of 30 observational variables. It was important to maintain and strengthen the quality attributes of coffee shops in this area because IPA(Importance Performance Analysis) analysis showed that "Doing great, keep it well" part was a desirable area because it had high importance and performance. Finally, path analysis revealed that customer satisfaction was influenced by employee attitude and affected revisit intention and recommendation intention.

• Journal of Information Processing Systems
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• v.17 no.2
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• pp.213-226
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• 2021

Given that most of the link prediction algorithms for signed social networks can only complete sign prediction, a novel algorithm is proposed aiming to achieve both link prediction and sign prediction in signed networks. Based on the structural balance theory, the local link tightness and global link tightness are defined respectively by using the structural information of paths with the step size of 2 and 3 between the two nodes. Then the total similarity of the node pair can be obtained by combining them. Its absolute value measures the possibility of the two nodes to establish a link, and its sign is the sign prediction result of the predicted link. The effectiveness and correctness of the proposed algorithm are verified on six typical datasets. Comparison and analysis are also carried out with the classical prediction algorithms in signed networks such as CN-Predict, ICN-Predict, and PSNBS (prediction in signed networks based on balance and similarity) using the evaluation indexes like area under the curve (AUC), Precision, improved AUC', improved Accuracy', and so on. Results show that the proposed algorithm achieves good performance in both link prediction and sign prediction, and its accuracy is higher than other algorithms. Moreover, it can achieve a good balance between prediction accuracy and computational complexity.

• Journal of Distribution Science
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• v.19 no.7
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• pp.61-73
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• 2021

Purpose: This study offers suggestions to e-commerce companies for increasing shoppers' repurchase intention by considering the effect of distribution information in online shopping. It applies complexity theory to incorporate habitual information search behavior and shopper characteristics into the Stimulus-Organism-Response model and indicates how these complex factors work together in online shopping. Research design, data, and methodology: This study used an interview survey of 158 Vietnamese consumers with an experience of online shopping. A fuzzy-set Qualitative Comparative Analysis (fsQCA) was used to examine the relationship between antecedents and outcomes depending on complex conditions in the given contexts. Results: The results (1) indicate the importance of observing information search patterns and investigating their influence on online distribution, and (2) clarify what kind of configurations, under what conditions, predict a high or low outcome; this provides evidence and hints for the development of frameworks for future studies. Conclusions: The findings suggest that shoppers' unconscious, habitual behavior can work with conscious attitude factors, such as satisfaction, to increase their repurchase intention. Hence, e-commerce companies should consider how to present useful distribution information and create functions that allow shoppers to engage with a variety of information while increasing their repurchase intention on the site.

• Advances in concrete construction
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• v.16 no.5
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• pp.269-276
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• 2023

In order to study the effect of rubber particle size and admixture on the frost resistance of self-compacting concrete, three self-compacting concrete specimens with equal volume replacement of fine aggregate by rubber particles of different particle sizes were prepared, while conventional self-compacting concrete was made as a comparison specimen. The degradation law of rubber aggregate self-compacted concrete under freeze-thaw cycles was investigated by fast-freezing method test. The results show that the rubber aggregate has some influence on the mechanical properties and freeze-thaw durability of the self-compacting concrete. With the increase of rubber aggregate, the compressive strength of self-compacting concrete gradually decreases, and the smaller the rubber aggregate particle size is, the smaller the effect on the compressive strength of the matrix; rubber aggregate can improve the frost resistance of self-compacting concrete, and the smaller the rubber particle size is, the more obvious the effect on the improvement of the frost resistance of the matrix under the same dosage. Through the research of this paper, it is recommended to use 60~80 purpose rubber aggregate and the substitution rate of 10% is chosen as the best effect.

• The Journal of Korean Philosophical History
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• no.50
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• pp.9-36
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• 2016

This thesis aims to suggest probability of modern confrontation of Yulgok YiYi's thought. For this, find out the meaning of Li-Qi-Zhi-Miao(理氣之妙) and through the Qi-Fa-Li-Cheng-Yi-Tu(氣發理乘一途), and Li-Tong-Qi-Ju-Shou(理通 氣局說), Yin-Xim-Do-Xim-Shou(人心道心說), he creatively reveal the relation of Xin(心) Xing(性) Qing(情) Yi(意) continually. On one side he suggested the way of ideal man, on the other side he was showed adaptablity to the real world. So I think Yulgok had placed emphasis on the Zhongyong(中庸) and Yijing(周易), so he point out the meaning of ShiZhong (時中). Then he had high ideals practical Zhi-Zhonghe((致中和). So This paper is to find out his foundation of epistemology, and then to know It's modern meaning of methodology of moral Education's Implication on the relation of Xin(心) Xing(性) Qing(情) Yi(意). So We ca find out Ji(機) is very important the transition of Qi-Zhe(氣質).

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 1995.10a
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• pp.39-43
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• 1995

본 연구에서는 퇴적물 이동에 의한 해빈단면 및 해안선의 변화 형태를 파랑모델이나 순환모델의 도움없이 예측하는 간단한 수치 모델을 제시하는 데 그 목적이 있다. 해안선의 변형에 대한 연구는 그동안 많은 진척되었으며 최근 해빈단면의 변형 모델은 물론 3차원적인 복잡한 해저면에도 적응할 수 있는 복합적인 토사이동 모델이 활발히 개발되고 있다(Watanabe 등, 1980； Wang and Miao, 1992； 과학기술처, 1992). (중략)

• Journal of Power Electronics
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• v.9 no.6
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• pp.854-865
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• 2009

Super-lift dc-dc converters are a series of advanced step-up dc-dc topologies that provide high voltage transfer gains by super-lift techniques. This paper presents a developed graphical modelling method for super-lift converters and gives a thorough analysis with a consideration of the effects caused by parasitic parameters and diodes' forward voltage drop. The general guidelines for constructing and deriving graphical models are provided for system analysis. By applying it to examples, the proposed method shows the advantages of high convenience and feasibility. Both the circuit simulation and experimental results are given to support the theoretical analysis.

• 한국균학회소식:학술대회논문집
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• 2009.10a
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• pp.70-75
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• 2009

• Journal of applied mathematics & informatics
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• v.26 no.5_6
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• pp.839-850
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• 2008

In this paper, the symmetric accelerated overrelaxation (SAOR) method for solving $n{\times}n$ fuzzy linear system is discussed, then the convergence theorems in the special cases where matrix S in augmented system SX = Y is H-matrices or consistently ordered matrices and or symmetric positive definite matrices are also given out. Numerical examples are presented to illustrate the theory.