• Journal of Electrical Engineering and Technology
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• 제9권3호
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• pp.899-907
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• 2014

This paper deals with fault-tolerant control of five-phase induction motor (IM) drives under single-phase open. By exploiting a decoupled model for five-phase IM under fault, the indirect field-oriented control ensures that electromagnetic torque oscillations are reduced by particular magnitude ratio currents. The control techniques are developed by the third harmonic current injection, in order to improve electromagnetic torque density. Furthermore, Proportional Resonant (PR) regulator is adopted to realize excellent current tracking performance in the phase frame, compared with Proportional Integral (PI) and hysteresis regulators. The analysis and experimental results confirm the validity of fault-tolerant control under single-phase open.

• 한국식품조리과학회지
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• 제19권2호
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• pp.155-164
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• 2003

The purpose of this study was to examine, in a service context, construct validity and generalizability of widely used and accepted measures of perceived organizational support, job satisfaction, organizational commitment, and service duality, and to test each measures' predictive utility in this context with path analysis. Of 350 subjects, 309 subjects participated in the analysis. Descriptive statistics (frequencies), exploratory factor analysis, reliability analysis, zero-order partial correlation analysis, and confirmatory factor analysis were used for this study. The findings from this study are as follows. First, perceived organizational support significantly influenced job satisfaction, organizational commitment. and service quality. Second, Job satisfaction had a directional impact upon organizational commitment and service quality. Third, organizational commitment showed to have a predictive impart on service quality. Finally, the results of the study provide some insight into the types of internal marketing strategies that can be applied successfully by operators of hotel F & B departments.

• 한국콘텐츠학회논문지
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• 제21권12호
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• pp.47-56
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• 2021

본 연구는 네트워크 분석을 활용하여 대학생 인성 관련 연구의 동향을 파악하고 향후 연구 방향의 시사점을 제공하는데 그 목적이 있다. 이러한 연구목적을 위해 국내 학술지에 게재된 대학생 인성 관련 논문 194편을 대상으로 하였다. 연구결과를 정리하면 다음과 같다. 첫째, 대학생 인성 관련 연구는 2004년부터 발표되기 시작하여 2012년에 소폭 상승하였고, 2015년부터 상승곡선을 이어가다 2017년에 정점을 찍은 후, 하향추세인 것으로 확인된다. 둘째, 연결 중심성과 매개 중심성 분석에서 공통적으로 가장 높은 중심성을 가진 핵심 키워드는 '사회'와 '함양'이었다. 셋째, 1기(2004년-2010년)에는 개인적 차원과 인성의 인지적인 측면의 키워드, 2기(2011년-2015년)에는 사회적인 차원과 인성의 정서적인 측면의 키워드, 3기(2016년-2020년)에는 사회적인 차원과 인성의 인지·정서·행동적인 측면의 키워드가 핵심적이었다. 넷째, 토픽모델링 분석결과, 능력, 생활, 대인, 만족, 적응의 키워드로 이루어진 토픽 2와 역량, 도덕, 시민, 사회, 실천으로 이루어진 토픽 1이 가장 높은 비중을 차지하였다. 다섯째, 1기에는 토픽 4 단독, 2기에는 토픽 1과 토픽 2의 순으로, 3기에는 토픽 2와 토픽 1의 순으로 높은 비중을 차지하는 것으로 나타났다. 본 연구는 대학생 인성 관련 연구에 유용한 근거자료가 될 것이다.

• Journal of Microbiology and Biotechnology
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• 제28권5호
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• pp.784-795
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• 2018

Bacillus amyloliquefaciens Pc3 was isolated from Antarctic seawater with antifungal activity. In order to investigate the metabolic regulation mechanism in the biosynthesis of lipopeptides in B. amyloliquefaciens Pc3, GC/MS-based metabolomics was used when exogenous indole was added. The intracellular metabolite profiles showed decreased asparagine, aspartic acid, glutamine, glutamic acid, threonine, valine, isoleucine, hexadecanoic acid, and octadecanoic acid in the indole-treated groups, which were involved in the biosynthesis of lipopeptides. B. amyloliquefaciens Pc3 exhibited a growth promotion, bacterial total protein increase, and lipopeptide biosynthesis inhibition upon the addition of indole. Besides this, real-time PCR analysis further revealed that the transcription of lipopeptide biosynthesis genes ituD, fenA, and srfA-A were downregulated by indole with 22.4-, 21.98-, and 26.0-fold, respectively. It therefore was speculated that as the metabolic flux of most of the amino acids and fatty acids were transferred to the synthesis of proteins and biomass, lipopeptide biosynthesis was weakened owing to the lack of precursor amino acids and fatty acids.

• 대한가정학회지
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• 제44권5호
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• pp.79-87
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• 2006

The purpose of this study is to analyze whether service quality and perceived risk have an effect on purchase intention and satisfaction of the fashion merchandise in internet shopping malls. To this end, a survey was conducted from June 20 to July 30 in 2005, among married women aged in their 20s and 30s, on their purchase experience of fashion merchandise from internet shopping malls. The survey was conducted over the internet with 306 subjects. The statistical analysis methods were frequency analysis, reliability analysis, factor analysis, and multiple regression analysis. First, the service quality factors were determined to be reliability, responsibility, ease of transaction, order convenience, and site characteristics. Perceived risk factors were determined to be merchandise risk, information exposure risk, social psychological risk, and function risk. Second, service quality factors of responsibility, ease of transaction, order convenience, site characteristics and perceived risk factor of social psychological risk had an effect on internet purchase intention of the fashion merchandise. Greater site use convenience, lower price, simpler ordering, and lower social psychological risk were all positively correlated with higher internet purchase intention of fashion merchandise. Third, nice quality factors and social psychological risk had an effect on satisfaction degree in internet shopping.

• 반도체디스플레이기술학회지
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• 제19권4호
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• pp.22-27
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• 2020

In this paper, a generalized efficiency equation was proposed to estimate the internal loss of the SMPS (switched-mode power supply) with 3 variables. The first variable was an internal loss not related to the load current such as auxiliary power, the second was a loss proportional to the current such as diode loss, and the third was a loss proportional to square of the current such as conduction loss. Especially, theoretical internal losses of the totem pole bridgeless PFC which is widely used for high efficiency SMPS were expressed as output function to compare generalized efficiency equation. In addition, in order to reduce the conduction loss of the switch, when a multiple switch were paralleled, the correlation with the efficiency was analyzed and shown as a graph. In order to confirm the degree of the parallel switch structure on the efficiency improvement, a 2kW class totem pole bridgeless PFC was constructed and the effectiveness of the analysis was confirmed by comparing the generalized efficiency equation and theoretical loss analysis results with experimental data.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1988년도 한국자동제어학술회의논문집(국제학술편); 한국전력공사연수원, 서울; 21-22 Oct. 1988
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• pp.1055-1058
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• 1988

A systematic way of failure diagnosis in a linear system with decentralized estimators is developed. The generalized likelihood ratio (G.L.R) approach to failure detection and identification is used for designing a diagnosis system in each subsystem based on the innovation analysis. For the simplicity of the theoretical formulation, a design scheme of failure diagnosis is developed for the system decomposed into two subsystems. To demonstrate the effectiveness of our approach, several simulation studies have been carried out on a third-order linear system which is constructed of a second-order damped oscillator and a first-order lag.

• Journal of Mechanical Science and Technology
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• 제17권12호
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• pp.1867-1875
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• 2003

In exhaust pipes of automotive engines, the pulsating pressure waves are composed of fundamental frequency and high order harmonics. The nonlinearities in the exhaust pipe is caused by their interactions. The error between prediction and measurement is induced by the nonlinearities. We can not explain this phenomenon using linear acoustics theory. So power spectrum, which is used in linear theory, is not useful. This paper is concerned with the development of useful engineering techniques to detect and analyze nonlinearity in exhaust pipe of automotive engines. The study of higher order statistics has been dominated by work on the bispectrum. The bispectrum can be viewed as a decomposition of the third moment (skewness) of a signal over frequency and as such is blind to symmetric nonlinearities. The phenomenon of quadratic phase coupling (QPC) can be analyzed by the bicoherence function. Finally the application of these techniques to data from actual exhaust pipe systems is performed.

• 기술경영경제학회:학술대회논문집
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• 기술경영경제학회 2000년도 제17회 하계학술발표회 논문집
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• pp.65-83
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• 2000

In this study, we propose an expert system aided model necessary for extracting the rules, which can diagnose the success level of new product development project. For this purpose, first, we design a classification model to analyze the characteristics of $\ulcorner$parts development projects$\lrcorner$. Second, in order to select success factors, we explore literatures and interview with project managers working at large sized companies of electronic parts. And we conduct the enquete survey and statistical analysis to extract key success factors. Third, in order to decide the level of project success, we use the concept of 'Recearchitivity' as a framework of judgement criteria. Fourth, in order to extract diagnosis rules, we use expert system development tool.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 Ⅳ
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• pp.2451-2454
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• 2003

In this paper, we propose the computation reduction methods of LSP(Line spectrum pairs) transformation that is mainly used in CELP vocoders. In order to decrease the computational time in real root method the characteristic of four proposed algorithms is as the following. First, scheme to reduce the LSP transformation time uses met scale. Developed the second scheme is the control of searching order by the distribution characteristic of LSP parameters. Third, scheme to reduce the LSP transformation time uses voice characteristics. Developed the fourth scheme is the control of searching interval and order by the distribution characteristic of LSP parameters. As a result of searching time, computational amount, transformed LSP parameters, SNR, MOS test, waveform of synthesized speech, speech, spectrogram analysis, searching time reduced about 37.5％, 46.21％, 46.3％, 51.29％ in average, computational amount is reduced about 44.76％, 49.44％, 47.03％, 57.40％. But the transformed LSP parameters of the proposed methods were the same as those of real root method.