• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.1058-1065
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• 2015

This paper present a current predicting control method for PMSM (permanent magnet synchronous motor) to improve the tracking performance of stator current, which regards the current vector as the control target. Solving the model state equation in the static frame (α-β frame), the dynamic change of current vector will be gained as three independent terms. These change terms, which contain the prediction of current vector, are discretized and simplified by Taylor series expansion and used to get the voltage vector as the predictive control quantity. SVPWM will transform the control voltage to the switching signal of inverter, which is newly deduced for the current vector. Simulation and experiment results are given to testy and verify the performance of this method.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.5
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• pp.355-364
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• 2002

The goal of this research is to reduce noise level of an outdoor unit of air conditioner by changing its dynamic characteristics using SDM (structural dynamics modification) technique. At first, the emitting noise was measured and analyzed. The measurement records show the most critical frequency components which influences on the noise level. Then it was tried to move the natural frequencies outside the critical frequency region by SDM. Since it is very difficult to get a reliable FE model of air conditioner, experimentally measured frequency response functions were used to derive sensitivities that are very important to obtain design changes. The positions of modification and the thickness of modifying structures were determined to improve the dynamic characteristics of air conditioner. The recommended design guideline to move its natural frequencies outside the targeting frequency range was obtained. Then in order to prove its effectiveness, the changed design was experimentally tested and found that the SDM result is very effective to reduce not only its vibration but also its emitting noise.

• Journal of Venture Innovation
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• v.6 no.1
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• pp.95-114
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• 2023

As the Fourth Industrial Revolution progresses, the importance of startups is becoming more prominent. Additionally, the role of accelerators in ensuring the sustainability of startups is also being emphasized. Therefore, in this study, among the services provided by accelerators to startups, the mentoring service, education service, funding service, and networking service tried to empirically analyze the structural relationship that affects startup performance through the dynamic capabilities of start-ups. To achieve this, we conducted a survey in February 2023 targeting startup CEOs and executives who had experience with accelerator program services. A total of 238 valid responses were analyzed using structural equation modeling with Amos 24. The results of the empirical analysis were as follows. The accelerator program services, including mentoring, education, funding, and networking services, had a significant positive effect on startup dynamic capabilities. Among the accelerator program sub-factors, networking services had the highest impact on startup dynamic capabilities, followed by mentoring, funding, and education services. Furthermore, startup dynamic capabilities were found to have a significant positive effect on startup performance. On the other hand, startup dynamic capabilities were found to mediate the relationship between mentoring, education, funding, networking services, and startup performance. Dynamic capabilities are a critical factor for startups, and the finding that accelerator programs can have a significant impact on startup performance by mediating these dynamic capabilities is significant both academically and practically.

• Journal of The Korean Association of Information Education
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• v.16 no.4
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• pp.475-482
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• 2012

A class is a complex and interactive process between a teacher and students. This paper describes a software design and implementation of the tool easily to analyze and quantize teaching ability. Our proposed software is implemented based on Flanders linguistic method. The software can easily represent the linguistic analysis results by abstracted graphic drawings. We carry out the performance test of our implemented software targeting incumbent teachers. In the experimental, we could demonstrate the effectiveness and practicality of our implemented software.

• Proceedings of the IEEK Conference
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• 2004.06a
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• pp.11-14
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• 2004

Digital Video Broadcasting - Satellite (DVB-S) [1] (EN 300 421(bibliography)) was introduced as a standard in 1994. However, by combing with higher order modulation, promise more powerful alternatives to the DVB-S / DVB-DSNG coding and modulation schemes. Variable rate coding and modulation (VCM) may employed to provide different levels of error protection to different service components. Adaptive coding and modulation (ACM) provides more exact channel protection and dynamic link adaptation to propagation conditions, targeting each individual receiving terminal. By these reasons, DVB-S2 introduced. This paper derives exact symbol error rate(SER) of 16-Amplitude Phase Shift Keying(APSK) modulation by using Craig's formula. 16-APSK modulation is used in DVB-S2. The difference between Union Bound and Craig's formula is 1.26dB in low SNR and 0.1dB in high SNR.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.5 s.176
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• pp.1271-1280
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• 2000

A sensor placement technique to identify structural parameter was developed. Experimental results must be acquired to identify unknown dynamic characteristics of a targeting structure for the comparison between analytical model and real structure. If the experimental environment was not equipped itself properly, it can be happened that some valuable information are distorted or ill-condition can be occurred. In this work the index to determine exciting points was derived from the criterion of maximizing parameter sensitivity matrix and that to choose measurement points was from that of preserving the invariant of sensitivity matrix. This idea was applied to a compressor hull structure to verify its performance. The result shows that the selection of measurement and excitation points using suggested criteria improve the ill-conditioning problem of inverse type problems such , as model updating.

• The Research Journal of the Costume Culture
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• v.9 no.5
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• pp.783-797
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• 2001

This study examines the cultural meanings of underclothes advertisements through the analysis of advertisement messages appeared in women's magazines of Korea which are , and published between 1965 and 1999 mainly targeting the women at the age of 20s through 40s. The method of study is mainly qualitative with subsidiary citations from the results of content analysis. The advertisement messages identified in underclothes advertisements are 1) body care, 2) gender role, 3) commercialization of eroticism, 4) feminism, 5) men's social status and masculinity, 6) social issues of concern and ideologies of the time. Advertisements produce a new meaning through a dynamic mixture of the advertisement's visual and verbal factors. Such a new meaning then can become a part of culture and therefore we can obtain insights of a society culture by analyzing the advertisement messages of underclothes advertisements. Advertisements bring definite changes to the culture through long-term and implicit influences on the constituents of the culture.

• Journal of applied mathematics & informatics
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• v.29 no.3_4
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• pp.721-741
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• 2011

In this paper we have considered a dynamical mathematical model of the sub-populations of potential smokers (non-smokers), smokers, smokers who temporarily quit smoking, smokers who permanently quit smoking and a class of smoking associated illness by introducing time dependent parameters and distributed time delay to acquire smoking habit. Here, we have established some sufficient conditions on the permanence and extinction of the smoking class in the community by using inequality analytical technique. We have introduced some new threshold values $R_0$ and $R^*$ and further obtained that the smoking class in the community will be permanent when $R_0$ > 1 and the smoking class in the community will be going to extinct when $R^*$ < 1. By Lyapunov functional method, we have also obtained some sufficient conditions for global asymptotic stability of this model. Computer simulations are carried out to explain the analytical findings. The aim of the analysis of this model is to identify the parameters of interest for further study, with a view to informing and assisting policy-maker in targeting prevention and treatment resources for maximum effectiveness.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.6
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• pp.39-46
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• 2023

In this study, the dynamic behavior of friction bearings of PSC (Pre-Stressed Concrete) box train continuous bridge was numerically analyzed at 10 km/h intervals up to 600 km/h according to the increasing speed of the next-generation high-speed train. A frame model was generated targeting the 40-meter single-span and two-span continuous PSC box bridges in the Gyeongbu High-Speed Railway section. The interaction forces including the inertial mass vehicle model with 38 degrees of freedom and the irregularities of the bridge and track were considered. It was calculated the longitudinal displacement, cumulative sliding distance and displacement speed of the bridge bearings at each running speed so that compared with the dynamic behavior trend analysis of the bridge. In addition, long-term friction test standards were applied to evaluate the durability of friction plates.

• The Research Journal of the Costume Culture
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• v.18 no.5
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• pp.809-823
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• 2010

The 21st century is the age of culture and sensitivity. As the interest in the art and culture grows, Artygen who prefers artistic designs grow in number. The desire to enjoy life from the increase of leisure time and financial afford ability created a new trend of party culture. This study analyzes the characteristics of Artygen who pursues artistic sense and sensitivity and suggests party-wear designs that please Artygen and accentuate individuality and personal preferences in a party, which is a type of popular entertainment these days. Through literature review, the background of Artygen and party was examined; First, in order to analyze the feature of art designs, photos of products that were in fashion from 2007 to 2009, (during which the term, 'Artygen', was coined) were collected. Second, in order to analyze the party-wear designs, photos of party-wear in wine party and club party popular among young people in the 20~30's were collected. Through the analysis, the party-wears targeting Artygen was developed based on the characteristics of popular art designs. The results of this study were as follows. First, from the result of analyzing the art design shown in product, casual, romantic, modern, dynamic and gorgeous images were. Second, art design shown in fashion, casual, romantic, chic, dynamic and gorgeous images were. Third, in wine party, romantic, elegant, gorgeous and formal images were in order and in club party, casual, gorgeous, chic and romantic images were in order. Fourth, the study displayed design by connecting aesthetic factor of artistic design to 2 wine party-wear of romantic and gorgeous images and 3 club party dresses of casual, gorgeous and chic images.