• Journal of the Korea Institute of Information and Communication Engineering
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• v.3 no.3
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• pp.559-567
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• 1999

A piezoelectric flextentional sonar transducer has been simulated using a coupled FE-BEM. The dynamics of the sonar transducer is modelled in three dimensions and is analyzed with external electrical excitation conditions. Different results are available such as steady-state displacement modes, underwater directivity patterns, resonant frequencies, bandwidths, quality factors, output acoustic powers and transmitting voltage responses. It is shown that the present barrel-stave sonar transducer of the piezoelectric material produces flextentional displacements which could be related with higher output power, lower quality factor and more omnidirectional beam pattern than other types of sonar transducers. The results of the present sonar transducer modelling are also compared with those of a commercial package such as ATILA.

• Journal of Power Electronics
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• v.11 no.5
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• pp.655-661
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• 2011

This paper presents two topologies for single-stage single-phase double-buck type PFC converters, designed to operate at high power factor, near sinusoidal input currents and adjustable output voltage. Unlike the known buck type PFC topologies, in which the output voltage is always lower than the maximum input voltage, the proposed converters can operate at output voltages higher than the ac input peak voltage. A reduced number of switches on the main path of the current are another characteristic of the two proposed topologies. To shape the input line currents, a fast and robust controller based on a sliding mode approach is proposed. This active non-linear control strategy, applied to these converters allows high quality input currents. A Proportional Integral (PI) controller is adopted to regulate the output voltage of the converters. This external voltage controller modulates the amplitude of the sinusoidal input current references. The performances of the presented rectifiers are verified with experimental results.

• Journal of Information Management
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• v.43 no.2
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• pp.23-42
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• 2012

This study is to investigate and analyze the service quality and satisfaction perceived by users and librarians of the Foreign Research Information Center (FRIC). The survey results reveal that three groups of in-campus (internal) user group, external user group and interlibrary loan librarian group has highly perceived the service quality and satisfaction of the FRIC. Two user groups have statistically significant different perceptions on the service quality, loyalty, and satisfaction. Internal user group perceived more highly than external user group, in 6 items of satisfaction, 1 item of loyalty, and 7 items of service quality. Structural equation models of satisfaction and loyalty on two user groups were proved to be appropriate. Material factor including success rate of copied text and general physical status of the copy influences significantly on the user satisfaction in both groups.

• Korean Journal of Agricultural Science
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• v.50 no.4
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• pp.869-881
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• 2023

A genetic improvement program in Korea was implemented to improve the performance of Hanwoo cattle by generating livestock with genetically desirable economic characteristics. In particular, in response to external changes, such as the expansion of Free Trade Agreement (FTA), the livestock genetic improvement program has increased farm income by improving the productivity and quality of Hanwoo cattle. Using production cost data from Statistics Korea, the total input and output indices of Hanwoo feeding cattle from 2008 - 2021 were estimated and the growth and productivity changes were analyzed. The productivity change measures results were used to estimate the cumulative effects of the Hanwoo genetic improvement program on quality improvement, another purpose of the program, using a finite distributed lag model. The average annual increase in output (market weight) of Hanwoo was 0.9%. However, total input increased by 1.6%, resulting in a 0.6% decline in total factor productivity. In contrast, the Hanwoo genetic improvement program contributed significantly to the production of high quality beef, rather than contributing to improved productivity of the cattle. Hanwoo carcass weight, which is used as a performance indicator for the livestock genetic improvement program, has significantly improved and is projected to increase at a slower rate. The collective findings indicate the need for new performance indicators that can comprehensively indicate the performance of the genetic improvement of Hanwoo.

• Journal of the Korean GEO-environmental Society
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• v.9 no.1
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• pp.17-25
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• 2008

In this study, external and internal pit growth rate model and external non-linear regression corrosion model were proposed by measuring pit depths and evaluating various soil factors known to contribute to the corrosion for metallic water pipes. Average pit depths of external and internal for metallic water pipes were measured 1.38 mm and 2.13 mm, and internal pit growth rate also fasted twice than external pit growth rate. This means the corrosion potential of water quality was higher than soil. The corelation between external corrosion rate and each soil corrosion factor was low. However, proposed external non-linear regression corrosion model considering all soil corrosion factors showed a little higher correlation ($R^2=0.46$) than conventional model.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2005.11a
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• pp.115-119
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• 2005

This study is to examine changes since autonomy of lotting-out price of apartment house and planning factors related to sale of apartment house through leaflet of sale of apartment house. Objects of the study were leaflets of sale of apartment houses through the Donga Il Bo daily newspaper from 2001 to 2003. The results of research can be summarized to three. First, traffic of locational factors in advertisement of sale of apartment house showed the highest frequency and it was found that it was an important planning factor of apartment house. Second, considering that advanced facilities and the highest finishing materials were used, quality of apartment house has been advanced. Third, considering that community space, theme park and green zone showed high occupancy in external space, there has been high increase in external space as well as in internal one since autonomy of lotting-out price.

• Journal of Practical Agriculture & Fisheries Research
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• v.22 no.1
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• pp.87-98
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• 2020

This study analyzed milk consumption behavior of college students. According to the results of the analysis, the respondents mainly purchase milk with a capacity of 900 to 1,000 ml at the hypermarket. However, it was found that convenience stores mainly purchase 200 ml capacity. According to the results of factor analysis on milk purchase factors, milk purchase factors were classified into nutritional and cosmetic attributes. Nutritional properties include nutritional ingredients, sterilization method, bio-origin, quality, HACCP labeling, milk fat ratio, etc., and external properties include brand, manufacturer, packaging/package design, and manufacturing date. In order to expand the milk consumption of the young generation, I think it is necessary to strengthen marketing strategies.

• The Research Journal of the Costume Culture
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• v.17 no.4
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• pp.548-560
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• 2009

This study was conducted to investigate purchasing behavior of jeans consumers and to find differences in jeans evaluative criteria according to consumers' characteristics. Male and female university students participated in the study. Quota sampling method was used to collect the data. Data from 492 questionnaires were used for the statistical analysis. Descriptive analysis, factor analysis, Cronbach's alpha coefficient, ANOVA, Duncan test, and t-test were conducted. Three factors of jeans evaluative criteria classified (i.e., external criteria, internal/aesthetic criteria, internal/quality criteria). Results indicated that most of respondents put on jeans wear more than three times per a week and 38.1% of respondents reported that they owned three to four jeans products on average. Department store was the most used place to buy jeans product with 44.2%. 27.5% of respondents spent from 50,000 won to 100,000 won on purchasing jeans. Style was the highest important jeans evaluative criterion with 36.2%, followed by fitness, price, color, condition of washing treatment. Women respondents considered aesthetic criteria and quality criteria more importantly than men did. Respondents who were on a high income and spent more than 200,000 won per a month on apparel more concerned aesthetic criteria and external criteria than the other respondents did. Results of this study provide a basis for understanding jeans consumers' purchase behavior and evaluative criteria.

• IE interfaces
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• v.19 no.3
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• pp.255-269
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• 2006

Digital manufacturing(DM) is the ability to describe every aspect of the design-to-manufacture process digitally-using tools that include digital design, CAD, office documents, PLM(Product Life-cycle Management) systems, analysis software, simulation, CAM software and so on. The major automotive companies are already deeply invested in DM with almost every process being digital rather than paper-based. But it has taken a long time for the digital process to mature into something usable and there have been some major barriers that have prevented from the DM becoming a reality. Thus many companies hesitate to make a decision of implementing the DM. This paper deals with a study investigating which factors are important for implementing the DM to industries successfully. The extended technology acceptance model (ETAM) is used as the relation model of cause and effect. The quality of hardware, the quality of software, the range of collaboration among companies and the preference of the user are defined as the external factors. Interview method is used for gathering input data, and the results are analyzed with SPSS. The results indicate that four external factors are effective on the successful implementation of DM, and the perceived usefulness is most important.

• Korean Journal of Agricultural Science
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• v.37 no.2
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• pp.303-308
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• 2010

Surface color is the most important quality factor for the grade evaluation of cherry tomato. Color is one of the representative indicators for the maturity which is closely related to the internal quality of cherry tomato, such as firmness, sugar content, and acidity. This study was carried out to investigate the relationship between surface color and internal quality of cherry tomatoes harvested from both hydroponic and soil culture at different ripening stages. To calculate the color values of cherry tomatoes an automatic color imaging system was constructed. A specially designed image processing algorithm for the color measurement was developed. The color values of L*, a*, b* were calculated from the initial color values of RGB and then compared with the internal quality. Statistical analyses indicated that the internal quality was more highly correlated with the surface color than size of cherry tomatoes. Color image features were also investigated to detect external damage of cherry tomatoes. The value of (R value - R mean value)/R mean value was the most effective image feature for the detection of damaged areas on the surface of cherry tomatoes. The results of this study demonstrated the feasibility of color sorting process as an alternative of the conventional drum type size sorting system for cherry tomato industry.