• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1998년도 제13차 학술회의논문집
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• pp.429-434
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• 1998

The previously developed control design methodology, EALQR(Eigenstructure Assignment/LQR), has better performance than that of conventional LQR or eigen-structure assignment. But it has a constraint for the weigting matrix in LQR, that is the weighting matrix could be indefinite for high-order systems. In this paper, the effects of the indefinite weighting matrix in EALQR on the Sequency domain properties are analyzed. The robustness criterion and quantitative frequency domain properties are also presented. Finally, the frequency do-main properties of EALQR has been analyzed by applying to a flight control system design example.

• 전기학회논문지
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• 제58권5호
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• pp.923-928
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• 2009

The performance analysis and robust control of the interior permanent magnet synchronous motor(IPMSM) greatly depend on accurate value of its parameters. To achieve the high performance of torque control, it is necessary to consider exact inductance values because the inductances are nonlinear parameters of operating the IPMSM. Therefore many different methods have been performed for analysis of the methodology for the exact measurement of synchronous inductances. None of them is considered standard, and accuracy levels of all these methods are also not consistent. Among these experimental methods, the DC current decay test and the vector current control test are ideal for a laboratory environment. In this paper, these two test methods are compared by applying inductances to the IPMSM. The paper analyzes the measured inductances of the two methods and their differences with inductances obtained from the finite element method(FEM).

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 A
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• pp.171-173
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• 1993

This paper deals with a methodology of the dynamic voltage stability analysis. The several physical power system constraints e.q upper and lower lomit of SVC and OLTC are considered. The proposed equivalent load model is the combination induction motor and impedance load. The variation of System voltages and equivalent induction motor slips for actual power systems are simulated and plotted in this paper.

• 한국IT서비스학회지
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• 제1권1호
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• pp.119-139
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• 2002

It is noteworthy that IMT -2000 communication network based on All-HP/AIN(Advanced Intelligent Network) should accomodate current and future wire/wireless AIN service easily through integration and gearing AIN construction elements. In this paper. Intelligent Farmer model(I-Farmer Model) and methodology are suggested in order to solve the several problems including standardization on implementation of Q3 interface in Telecommunication Management Network(TMN) agents which is caused by heterogeneous platform environment and future maintenance. Also this paper proposes ITI algorithm transforming the system which is designed by I-Farmer model to Interface Specification Model(ISM) applying the I-Farmer model. In addition to ITI algorithm. we suggest NTS(Node to SIB) algorithm converting entity node and ILB/OLB component in agent system designed by the I-Farmer model to SIB of AIN GFP(Global Functional Plane) and to ASIB for application program.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 A
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• pp.337-339
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• 1995

A Linear Induction Machine(LIM) is the motor which is developed from an rotary induction machine. Usually, the electromagnetic field of an LIM is analyzed by Maxwell's equations. The structure of an LIM is different from a conventional rotary machine, an LIM has some particular characteristics such as the end effects. Hence, the mathematical analysis of an LIM is very complicated and the implementation of the equivalent model is difficult. In this paper, the dynamic equations and the equivalent model of a Double-sided short primary LIM(DLIM) is obtained by the winding function and a d-q theory. The validity of the proposed methodology is verified by numerical analysis.

• 한국정밀공학회지
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• 제15권11호
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• pp.108-120
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• 1998

In this paper, a new control system design algorithm, which has the advantages of the existing LQR and eigenstrcture assignment methods, is proposed. The method of the transformation matrix via block controller is utilized to develop the scheme. Using the proposed algorithm, LQR weighting matrices q and R, which satisfy the desired closed-loop eigenvalues and eigenvectors, can be achieved using only simple matrix computations. The usefulness of the proposed scheme is verified by applying to a numerical example and an automotive active suspension control system design.

• 한국의류학회지
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• 제45권4호
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• pp.661-673
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• 2021

The purpose of this study is to analyze the perceptions of obesity among appearance-conscious women in their 20s. It is intended to provide data necessary to produce garments for obese body types by identifying adult women's subjective assessments of obese body types and characteristics. The data were analyzed using Q Methodology in the QUANL program for PC. Type 1 was recognized as uniformly fat in the abdomen, with almost the same width and thickness. Type 2 was perceived to have more fat in the upper body and back, broad shoulders, and an inverted body type. Type 3 was perceived as having a fat lower half of the body, hips wider than the chest, and large thighs. Type 4 was identified as having few curves and fat concentrated in the abdomen. Further research of other age groups and regions is needed to ascertain the difference between perceived and actual body types.

• Journal of Korea Trade
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• 제25권7호
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• pp.19-40
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• 2021

Purpose - This paper's purpose is to investigate how foreign ownership and innovation affect firm value. Design/methodology - Firm innovation is defined as operational efficiency, which is calculated by adopting data envelopment analysis (DEA). Additionally, R&D intensity is included as a measure of innovation in the analysis. We used firm-level data from manufacturing companies in Korea. The sample comprised 3,753 firm-year observations for every year in the period 2003-2017. Findings - We found that foreign ownership and innovation are positively related to firm value (Tobin's Q). Foreign ownership moderates innovation's contribution to firm value, implying that foreign ownership may enhance the value relevance of firm innovation. In addition, we found that firm innovation partially mediates the relationship between foreign ownership and firm value. Originality/value - This highlights the important role of foreign investors' monitoring; wherein foreign investors enhance firm value by facilitating firm innovation. Our results suggest that foreign ownership can be crucial for innovation and may serve to address weak ownership structures.

• 대한간호학회지
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• 제30권6호
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• pp.1437-1454
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• 2000

This study was designed to identify the attitudes of the people on organ donation and transplantation. The purpose of this study was to provide data to help inspire organ donation, and promote registration yield so donor candidates will have more favorable recipients through Q-methodology. A Q-sample was developed through a review of the literature and interviews. Thirty-three statements made up the final Q-sample. The P-sample consisted of twenty-eight subjects, excluding chronic organic disorder. The Q-sorts by each subject were coded and analyzed with the QUNAL computer program. The results were as follows: This study discovered five different types of organ donation and transplantation of twenty- eight subjects. Type I is 'utilitarian.' The people of this type consider human life very valuable and they recognize that organ transplantation is an affirmative medicine that should be performed to extend human life. They believe that are saving others' lives by donating organs. Type II is 'sardonist.' The people of this type approve of organ transplantation usefulness, but they have no intention of participating in the program because of it may trample on human rights. Type III is 'individualist.' The people of this type consider it proper for the activation of organ transplantation by the legal system. They believe that organ donation a valuable too, but needs support through social benefits to donors. Yet, they have not intention of doing what they propose. Type IV is 'familist.' The people of this type have strong attachments to life but they think that organ donation and transplantation should be done between within a family. Type IV is disposition of family intensive consideration rather than altruistic and utilitarianism. Type V is 'deontologist.' The people of this type recognize the benefits of transplantation, but have a negative opinion of activation. They worry about ethical and social problems occurring in the development of modern medicine. They believe that death is the only natural end to life, so they have strong negative opinions of euthanasia and brain death compared to other types. They regard transplantation to be a non-human behavior, because it involves a removing organs and breaking the boundary of death. The findings of this study are only preliminary and serve as a baseline to understanding the subjectivity of individuals on organ donation and transplantation. Therefore, the subjectivity of the five types will be applied to formulate the educational programs and public relations strategies for organ donation because the public's awareness toward organ donation is closely related to their values, beliefs, and attitudes.

• 유통과학연구
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• 제12권2호
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• pp.59-71
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• 2014

Purpose - In recent years, many firms have attempted various approaches to cope with the continual increase of aviation transportation. The previous research into freight charge forecasting models has focused on regression analyses using a few influence factors to calculate the future price. However, these approaches have limitations that make them difficult to apply into practice: They cannot respond promptly to small price changes and their predictive power is relatively low. Therefore, the current study proposes a freight charge-forecasting model using time series data instead a regression approach. The main purposes of this study can thus be summarized as follows. First, a proper model for freight charge using the autoregressive integrated moving average (ARIMA) model, which is mainly used for time series forecast, is presented. Second, a modified ARIMA model for freight charge prediction and the standard process of determining freight charge based on the model is presented. Third, a straightforward freight charge prediction model for practitioners to apply and utilize is presented. Research design, data, and methodology - To develop a new freight charge model, this study proposes the ARIMAC(p,q) model, which applies time difference constantly to address the correlation coefficient (autocorrelation function and partial autocorrelation function) problem as it appears in the ARIMA(p,q) model and materialize an error-adjusted ARIMAC(p,q). Cargo Account Settlement Systems (CASS) data from the International Air Transport Association (IATA) are used to predict the air freight charge. In the modeling, freight charge data for 72 months (from January 2006 to December 2011) are used for the training set, and a prediction interval of 23 months (from January 2012 to November 2013) is used for the validation set. The freight charge from November 2012 to November 2013 is predicted for three routes - Los Angeles, Miami, and Vienna - and the accuracy of the prediction interval is analyzed using mean absolute percentage error (MAPE). Results - The result of the proposed model shows better accuracy of prediction because the MAPE of the error-adjusted ARIMAC model is 10% and the MAPE of ARIMAC is 11.2% for the L.A. route. For the Miami route, the proposed model also shows slightly better accuracy in that the MAPE of the error-adjusted ARIMAC model is 3.5%, while that of ARIMAC is 3.7%. However, for the Vienna route, the accuracy of ARIMAC is better because the MAPE of ARIMAC is 14.5% and the MAPE of the error-adjusted ARIMAC model is 15.7%. Conclusions - The accuracy of the error-adjusted ARIMAC model appears better when a route's freight charge variance is large, and the accuracy of ARIMA is better when the freight charge variance is small or has a trend of ascent or descent. From the results, it can be concluded that the ARIMAC model, which uses moving averages, has less predictive power for small price changes, while the error-adjusted ARIMAC model, which uses error correction, has the advantage of being able to respond to price changes quickly.