• 전력전자학회논문지
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• 제15권1호
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• pp.1-8
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• 2010

본 논문은 별도의 PWM-IC없이 저가 구현이 가능한 자려 발진 플라이백 컨버터의 대기전력 저감을 위한 회로를 제안한다. 제안된 자려발진 플라이백 컨버터는 기존 자려발진 플라이백 컨버터의 스위치 초기 동작을 위한 경로에서 발생하는 지속적인 전력손실 문제를 개선하기 위해 DC-Blocking 캐패시터를 삽입한 형태로써 약 1W의 대기전력 저감효과 및 시스템의 전력 변환 효율 향상이 가능하다. 본 논문에서는 제안된 회로의 동작원리를 설명하고, 실제 35W급 전원시스템을 구현하여 기존 회로와의 비교를 통해 제안된 회로의 타당성을 검증한다.

• The Journal of Asian Finance, Economics and Business
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• 제7권7호
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• pp.279-291
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• 2020

This study aims to develop the concept of innovation models with the marketing channel construct approach, marketing innovation, product segmentation, and customer insight; as well as improvements to the theory of resource-based combined with the method of service-dominant logic. This study approach is based on quantitative descriptive conducted with three stages of testing scenarios. The first test is the mapping of the innovation model construct through testing the validity and reliability with the moderation of customer orientation variables. The second scenario examines the relationship of influence between the independent variables on the dependent variable of 29 hypothetical analysis equation modeling. The unit of analysis was conducted on 497 SMEs involved in the food and beverage sectors, with the criteria being SMEs must have a rating of 4-5 points on the Go-Food applications software. The results shown that: 1) the construct used to develop an innovative model both directly and via moderation is positive and significant; 2) Through a complicated relationship that involves all components of the variable, it outlines a positive and significant effect except for the path of analysis (μ5). The theoretical and managerial implications state that the service-dominant logic approach and resource-based view theory have extreme reliability and interrelations.

• 한국소음진동공학회논문집
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• 제20권11호
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• pp.1089-1096
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• 2010

The relation between the vibration induced from machinery and the radiated sound is complicated. Acoustic intensity method is widely used to obtain the accuracy of noise measurement and noise identification. In this study, as groundwork, the complex acoustic intensity method is performed to identify noise source and transmission path on different free space point source fields. As an industrial application, the complex acoustic intensity method is applied to HVAC to identify sound radiation characteristics in the near field. Experimental complex acoustic intensity method was applied to HVAC, it is possible to identify noise sources in complicated sound field characteristics which noise sources are related with each other, and certificate the validity of complex acoustic intensity. Especially, it can be seen that complex acoustic intensity method using both of active and reactive intensity is vital in devising a strategy for identification of noise. Also, the vector flow of acoustic intensity was investigated to identify sound intensity distributions and energy flow in the near field of HVAC.

• 한국IT서비스학회지
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• 제7권2호
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• pp.197-221
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• 2008

This study is to identify quality factors having influence upon mobile internet service performance theoretically, derive the research model and the hypotheses concerning the cause and effect relationship between these factors and service performance and then analyze them empirically. In order to enhance the model's explanation power, trust and cognitive engagement as interviewing variables are included in the model. The theoretical background of this study was brought from relevant literature in the areas of the theory of reasoned action(TRA). technology acceptance model(TAM), product selection model, cognitive absorption theory and etc. The research model and hypotheses were statistically investigated and analysed through convergent and discriminant validity test, reliability test, and path analyses by means of statistical packages SPSS(12.0) and LISREL(8.72). For these empirical analyses. data were collected through the field survey of 373 users who were willing to continuously use the mobile internet services. Based on the results of the analyses, theoretical and practical significance and future study direction were suggested. The results of this study will be helpful to giving a guideline to companies such as mobile telecom, mobile contents provider and mobile handset manufactures when they have to establish the mobile Internet service marketing strategies.

• 대한가정학회지
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• 제51권1호
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• pp.89-95
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• 2013

The purpose of this study is to identify a causal relationship among green consumer behavior, environmental knowledge and environmental attitudes of students at the university of education. A total of 366 copies of questionnaires were used for the data analysis; 31 copies were excluded due to lack of response to any given question. To ensure the reliability and validity of the questions, technical statistics were performed, such as frequency, ratio, average, standard deviation, skewness, and kurtosis via SPSS 15.0, item-total correlation and the totality, and reliability analysis. A structural analysis was undertaken via AMOS 7.0 in a bootstrapping method in order to perform a path analysis among variables as well as to assess the suitability of the model. The findings of the study were led to the following conclusions: First, the causal model among green consumer behavior, environmental knowledge and environmental attitudes of students at the university of education is suitable to the empirical analysis on research variables. Second, the environmental attitudes of students at the university of education has a direct, positive effect on green consumer behavior. Third, the environmental knowledge of students at the university of education has an indirect, positive effect on green consumer behavior.

• The Journal of Asian Finance, Economics and Business
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• 제7권10호
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• pp.413-421
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• 2020

This study aims to develop a research framework to investigate the factors affecting organizational commitment among employees who are working in Foreign Direct Investment (FDI) enterprises in Vietnam. The authors designed an online survey distributed to employees in FDI enterprises, collecting the data from 312 employees. All scales in this study are adopted from previous studies; tools employed include Cronbach's Alpha, Exploratory Factor Analysis, and Confirmatory Factor Analysis (CFA) to examine the internal consistency, reliability, dimensionality, and validity of each variable. Then, the structural equation modelling (SEM) was utilized in order to estimate path correlations between variables. Results indicate that the leadership style has the strongest effect on organizational commitment, followed by job satisfaction and working performance. Moreover, working performance and job satisfaction are also influenced by leadership style. However, there is no statistical evidence to show that job satisfaction has an impact on working performance. In addition, bootstrapping method is used to show the indirect effect of variables; results reveal that leadership style, though, does not have indirect effect on working performance via job satisfaction, but it indirectly affects organizational commitment throughout working performance. In other words, the study finds that working performance mediates the link between leadership style and organizational commitment.

• 대한조선학회지
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• 제24권4호
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• pp.9-18
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• 1987

The hydrodynamic radiation forces acting on a ship travelling in waves have been conventionally treated by strip theories or by direct three dimensional approaches, most of which have been formulated in frequency domain. If the forward speed of a ship varies with time, or if its path is not a straight line, conventional frequency domain analysis can no more be used, and for these cases time domain analysis may be used. In this paper, formulations are made in time domain with applications to some problems the results of which are known in frequency domain. And the results of both domains are compared to show the characteristics and validity of time domain solutions. The radiation forces acting on a three dimensional body within the framework of a linear theory. If the linearity of entire system is assumed, radiation forces due to arbitrary ship motions can be expressed by the convolution integral of the arbitrary motion velocity and the so called impulse response function. Numerical calculations are done for some bodies of simple shapes and Series-60[$C_B=0.7$] ship model. For all cases, integral equation techniques with transient Green's function are used, and velocity or acceleration potentials are obtained as the solution of the integral equations. In liner systems, time domain solutions are related with frequency domain solutions by Fourier transform. Therefore time domain solutions are Fourier transformed by suitable relations and the results are compared with various frequency domain solutions, which show good agreements.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 1998년도 춘계학술대회 학술발표 논문집
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• pp.123-126
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• 1998

The theoretical foundations of GA are the Schema Theorem and the Building Block Hypothesis. In the Meaning of these foundational concepts, simple genetic algorithm(SGA) allocate more trials to the schemata whose average fitness remains above average. Although SGA does well in many applications as an optimization method, still it does not guarantee the convergence of a global optimum. Therefore as an alternative scheme, there is a growing interest in a co-evolutionary system, where two populations constantly interact and co-evolve in contrast with traditional single population evolutionary algorithms. In this paper, we propose a new design method of an optimal fuzzy logic controller using co-evolutionary concept. In general, it is very difficult to find optimal fuzzy rules by experience when the input and/or output variables are going to increase. So we propose a co-evolutionary method finding optimal fuzzy rules. Our algorithm is that after constructing two population groups m de up of rule vase and its schema, by co-evolving these two populations, we find optimal fuzzy logic controller. By applying the proposed method to a path planning problem of autonomous mobile robots when moving objects exist, we show the validity of the proposed method.

• Journal of Power Electronics
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• 제3권4호
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• pp.205-214
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• 2003

This paper proposes a simple control strategy based on the discontinuous PWM (DPWM) to balance the DC-link voltage of three-level neutral-point-clamped (NPC) inverter at low modulation index. It introduces new DPWM methods in multi-level inverter and one of them is used for balancing the DC-link voltage. The current flowing in the neutral point of the DC-link causes the fluctuation of the DC-link voltage of the NPC inverter. The proposed DPWM method changes the path and duration time of the neutral point current, which makes the overall fluctuation of the DC-link voltage zero during a sampling time of the reference voltage vector. Therefore, by using the proposed strategy, the voltage of the DC-link can be balanced fairly well and the voltage ripple of the DC-link is also reduced significantly. Moreover, comparing with conventional methods which have to perform the complicated calculation, the proposed strategy is very simple. The validity of the proposed DPWM method is verified by the experiment.

• 전기학회논문지
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• 제64권10호
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• pp.1448-1453
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• 2015

In this paper, we propose an alternative method of communication to improve the reliability of in-vehicle networks by jointly using wireless communication networks. Wired Communication networks have been used in vehicles for the monitoring and the control of vehicle motion, however, the disconnection of wires or hardware fault of networks may cause a critical problem in vehicles. If the network manager detects a disconnection or faults in wired in-vehicle network like the Controller Area Network(CAN), it can redirect the communication path from the wired to the wireless communication like the Zigbee network. To show the validity and the effectiveness of the proposed in-vehicle network architecture, we implement the Electronic Stability Control(ESC) system as ECU-In-the-Loop Simulation(EILS) and verify that the control performance can be kept well even if some hardware faults like disconnection of wires occur.