• Journal of Power Electronics
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• v.18 no.1
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• pp.266-276
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• 2018

This paper presents a new step-up and step-down multi-pulse auto-transformer rectifier unit (ATRU) topology. This structure can achieve a wide range of output voltages, which solves the problem of auto-transformer output voltage being difficult to regulate. Adding middle taps to the primary winding and reasonably setting the number of auto-transformer windings, constituted two groups of three-phase output voltages with a $30^{\circ}$ phase difference. Multi-pulse output DC voltage is obtained after a three-phase output voltage across two rectifier bridges and inter-phase reactor. Thus, the output DC voltage is related to the number and configuration of the auto-transformer winding. In this paper, the relationship between the voltage ratio of the auto-transformer and the ratio of winding, input current and auto-transformer kilovoltampere rating are deduced and validated by simulations. On this basis, the output voltage range is optimized. An experiment on two different voltage ratio principle prototypes was carried out to verify the correctness of the analysis design.

• Journal of Digital Contents Society
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• v.17 no.1
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• pp.1-10
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• 2016

< My Little Television > with the new format which extends one person media broadcasting to terrestrial broadcasting is creating a huge Topic Index. It started the first broadcast on April 2015 and has continued the number one in viewer rating in the same time. While viewers directly participate in the program through the Daum TV Pod and a host communicates with viewers in a real time, various opinions are being reflected on the program. While a lot of information about the program has spread through SNS, it has led to raising the viewer rating of program. Recently, the Topic Index on the program has been published through the big data analysis rather than the program evaluation only by the viewer rating. The research on the correlation between the program viewer rating and amount of buzz has increased. In this study, it has analyzed how the Topic Index which is an extended concept of the amount of buzz affects the viewer rating. Study results show that the Topic Index is analyzed to positively influence the viewer rating. It will give a lot of help in studying big data of SNS on the program.

• Journal of Korea Trade
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• v.24 no.7
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• pp.1-28
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• 2020

Purpose - This paper empirically investigates the predictors and main determinants of consumers' ratings of mobile applications in the Google Play Store. Using a linear and nonlinear model comparison to identify the function of users' review, in determining application rating across countries, this study estimates the direct effects of users' reviews on the application rating. In addition, extending our modelling into a sentimental analysis, this paper also aims to explore the effects of review polarity and subjectivity on the application rating, followed by an examination of the moderating effect of user reviews on the polarity-rating and subjectivity-rating relationships. Design/methodology - Our empirical model considers nonlinear association as well as linear causality between features and targets. This study employs competing theoretical frameworks - multiple regression, decision-tree and neural network models - to identify the predictors and main determinants of app ratings, using data from the Google Play Store. Using a cross-validation method, our analysis investigates the direct and moderating effects of predictors and main determinants of application ratings in a global app market. Findings - The main findings of this study can be summarized as follows: the number of user's review is positively associated with the ratings of a given app and it positively moderates the polarity-rating relationship. Applying the review polarity measured by a sentimental analysis to the modelling, it was found that the polarity is not significantly associated with the rating. This result best applies to the function of both positive and negative reviews in playing a word-of-mouth role, as well as serving as a channel for communication, leading to product innovation. Originality/value - Applying a proxy measured by binomial figures, previous studies have predominantly focused on positive and negative sentiment in examining the determinants of app ratings, assuming that they are significantly associated. Given the constraints to measurement of sentiment in current research, this paper employs sentimental analysis to measure the real integer for users' polarity and subjectivity. This paper also seeks to compare the suitability of three distinct models - linear regression, decision-tree and neural network models. Although a comparison between methodologies has long been considered important to the empirical approach, it has hitherto been underexplored in studies on the app market.

• Proceedings of the Korean Geotechical Society Conference
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• 2003.03a
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• pp.265-272
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• 2003

In this study, the rock mass classification results from the face mapping and the resistivity inversion data are compared and analyzed for the reliability investigation of the determination of the rock support type based on the surface electrical survey. To get the quantitative correlation, rock engineering indices such as RCR(rock condition rating), N(Rock mass number), Q-system based on RMR(rock mass rating) are calculated. Kriging method as a post processing technique for global optimization is used to improve its resolution. The result of correlation analysis shows that the geological condition estimated from 2D electrical resistivity survey is coincident globally with the trend of rock type except for a few local areas. The correlation between the results of 3D electrical resistivity survey and the rock mass classification turns out to be very high. It can be concluded that 3D electrical resistivity survey is powerful to set up the reliable rock support type.

• Journal of Applied Tourism Food and Beverage Management and Research
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• v.7
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• pp.41-59
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• 1997

After the industrial revolution, we have changed whole life-styles. This trend has brought a change in our eating style. Nowadays, the great number of people go out to eat-even three meals a day. As a result, the growth rate of food service industry increases day by day. Some restaurants are managed by the large scale company and others by the small scale ownership. Though developed countries are in the maturity step of the product life cycle in this field, we are in the growth step. We will hold the in 2002. A lot of tourists and the press will rush to Korea. They must have their meals at the restuarant. Therefore, we need more practice to satisfy them and to lead to successful management in this field. Also, we need an evaluation to qualify each business so that our food service industry does not decline compared to other country's. This study is trying to find how to evaluate and qualify each business in the various areas: service, the quality of food, the mood of the restaurant and so on. In addition, it includes the restaurant rating form.

• Knowledge Management Research
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• v.13 no.3
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• pp.55-77
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• 2012

Selecting promising technology is becoming more and more difficult due to the increased number and complexity. In this study, we propose hybrid AHP/DEA-AR method and hybrid AHP/DEA-AR-G method to evaluate efficiency of technology alternatives based on ordinal rating data collected through survey to technology experts in a certain field and select efficient technology alternative as promising technology. The proposed method normalizes rating data and uses AHP to derive weights to improve the credibility of analysis, then in order to avoid basic DEA models' problems, use DEA-AR and DEA-AR-G to evaluate efficiency of technology alternatives. In this study, we applied the proposed methods to clean technology and compared with the basic DEA models. According to the result of the comparison, we can find that the both proposed methods are excellent in confirming most efficient technology, and hybrid AHP/DEA-AR method is much easier to use in the process of technology selection.

• Journal of the Korea Society of Computer and Information
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• v.21 no.7
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• pp.9-16
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• 2016

Collaborative filtering(CF) uses the purchase or item rating history of other users, but does not need additional properties or attributes of users and items. Hence CF is known th be the most successful recommendation technology. But conventional CF approach has some significant weakness, such as the new user problem. In this paper, we propose a approach using word embedding with skip-gram for learning distributed item representations. In particular, we show that this approach can be used to capture precise item for solving the "new user problem." The proposed approach has been tested on the Movielens databases. We compare the performance of the user based CF, item based CF and our approach by observing the change of recommendation results according to the different number of item rating information. The experimental results shows the improvement in our approach in measuring the precision applied to new user problem situations.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.864-869
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• 2003

KS F 2808 was revised in 2000 and KS F 2862-1 was newly established in 2001. Thus Related Korean Industrial Standard such as KS F 4724, KS F 4735, KS F 4736 should be revised according to KS F 2808 and KS F 28612-1. This study aims to elicit the new rating numbers such as R$\sub$w/, R$\sub$w/＋C, R$\sub$w/＋C$\sub$tr/, L$\sub$m/ defined in KS F 2862-1 instead of exiting rating number; transmission loss of 500Hz.

• Journal of Acupuncture Research
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• v.39 no.1
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• pp.49-52
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• 2022

Benign essential blepharospasm (BEB) is a condition/disease which involves involuntary muscle contractions causing the eye to repetitively close, making it impossible for the patient to perform daily activities. This study reports Korean medicine treatment of a rare case BEB in a 34-year-old male patient whose symptoms showed minimal improvement following botulinum toxin injection (the standard treatment). Acupuncture, pharmacopuncture, and herbal medicine treatment for 11 days resulted in clinical improvement for all symptoms as assessed by using the Jankovic Rating Scale, Blepharospasm Disability Index, numerical rating scale, duration of spasms lasting more than 1 hour per day, and number of spasms lasting less than 1 minute per day. This case report suggests that comprehensive Korean medicine treatment could be a treatment option for BEB in patients who do not respond well to botulinum toxin injection.

• Journal of Advanced Information Technology and Convergence
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• v.9 no.2
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• pp.41-54
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• 2019

The cinema circuit is facing a digital, network, and mobile age, which expands non-theater accessibility to movies. Application platforms are situated as the most competitive business model that provide digital content such as games, music, books, and movies. Consumers can acquire content-related information not just offline, but online as well. Therefore, item information provided by application platforms is required. The information provided by application platforms consists of richly descriptive information such as storyline summary, consumer reviews, and related articles, while non-descriptive normative information covers data such as sales ranking, release date, genre, rental or purchase cost, domestic/foreign classification, consumer rating, number of consumer ratings, film rating, and so on. In this study, we surveyed and analyzed statistically the correlation between real-time sales ranking and other comparable non-descriptive information.