• Journal of Microbiology and Biotechnology
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• v.21 no.4
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• pp.430-437
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• 2011

The effects of the agitation and aeration rates on the production of serratiopeptidase (SRP) in a 5-L fermentor (working volume 2-l) were systematically investigated using Serratia marcescens NRRL B-23112. The dissolved oxygen concentration, pH, biomass, SRP yield, and maltose utilization were all continuously measured during the course of the fermentation runs. The efficiencies of the aeration and agitation were evaluated based on the volumetric mass transfer coefficient ($K_La$). The maximum SRP production of 11,580 EU/ml with a specific SRP productivity of 78.8 EU/g/h was obtained with an agitation of 400 rpm and aeration of 0.075 vvm, which was 58% higher than the shake-flask level. The $K_La$ for the fermentation system supporting the maximum production (400 rpm, 0.075 vvm) was 11.3 $h^{-1}$. Under these fermentor optimized conditions, kinetic modeling was performed to understand the detailed course of the fermentation process. The resulting logistic and Luedeking-Piret models provided an effective description of the SRP fermentation, where the correlation coefficients for cell growth, SRP formation, and substrate consumption were 0.99, 0.94, and 0.84, respectively, revealing a good agreement between the model-predicted and experimental results. The kinetic analysis of the batch fermentation process for the production of SRP demonstrated the SRP production to be mixed growth associated.

• Knowledge Management Research
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• v.17 no.2
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• pp.165-185
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• 2016

Though Korea has received attention through an exceptional economic growth and the big K-POP fever all over the world, its happiness level is not so high. Therefore, this research aims to find not only the Korean' s condition of the happiness and unhappiness, but also the way to enhance their happiness. We collected various web data(89,127 cases from 2013/01 to 2014/12) through searching our own 26 keywords based on Alderfer's ERG Theory. Also, we tried to analyze the subjects related to happiness and unhappiness by using LDA topic modeling. As the result, the condition of happiness and unhappiness were the top topics extracted from each field. We conducted the second detailed analysis based on the data of condition of the happiness and unhappiness which are the top topics of the previous analysis. From the second analysis result, we proposed several ways to enhance happiness from the perspective of government, corporate, family, education, social welfare.This paper is meaningful because it catches the condition of happiness and unhappiness based on a real web data as well as transform the data into the knowledge. Also, this paper provides the practical methods from the view from all walks of life that may enhance happiness and relieve unhappiness.

• Research in Community and Public Health Nursing
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• v.30 no.4
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• pp.449-459
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• 2019

Purpose: The aim of this study is to explore different types of self-rated health trajectories among one-person households in Korea. Methods: We used five time-point data derived from Korea Health Panel (2011~2015). A latent growth curve modeling was used to assess the overall feature of self-rated health trajectory in one-person households, and a latent class growth modeling was used to determine the number and shape of trajectories. We then applied multinomial logistic regression on each class to explore the predicting variables. Results: We found that the overall slope of self-rated health in one-person households decreases. In addition, latent class analysis demonstrated three classes: 1) High-Decreasing class (i.e., high intercept, significantly decreasing slope), 2) Moderate-Decreasing class (i.e., average intercept, significantly decreasing slope), and 3) Low-Stable class (i.e., low intercept, flat and nonsignificant slope). The multinomial logistic regression analysis showed that the predictors of each class were different. Especially, one-person households with poor health condition early were at greater risk of being Low-Stable class compared with High-Decreasing class group. Conclusion: The findings of this study demonstrate that more attentions to one-person households are needed to promote their health status. Policymakers may develop different health and welfare programs depending on different characteristics of one-person household trajectory groups in Korea.

• Journal of the Korean Society of Industry Convergence
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• v.27 no.3
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• pp.635-644
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• 2024

Although the business model(BM) patents act as a creative bridge between technology and the marketplace, limited scholarly attention has been paid to the content analysis of BM patents. This study aims to contextualize converging BM patents by employing topic modeling technique and clustering highly marketable topics, which are expressed through a topic-market impact matrix. We relied on BM patent data filed between 2010 and 2022 to derive empirical insights into the commercial potential of emerging business models. Subsequently, nine topics were identified, including but not limited to "Data Analytics and Predictive Modeling" and "Mobile-Based Digital Services and Advertising." The 2x2 matrix allows to position topics based on the variables of topic growth rate and market impact, which is useful for prioritizing areas that require attention or are promising. This study differentiates itself by going beyond simple topic classification based on topic modeling, reorganizing the findings into a matrix format. T he results of this study are expected to serve as a valuable reference for companies seeking to innovate their business models and enhance their competitive positioning.

• Journal of the Korean Society for Library and Information Science
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• v.57 no.1
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• pp.45-68
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• 2023

The purpose of this study is to longitudinally analyze impact factors on library use. One of library use indicators, the number of circulated books was statistically analyzed with latent growth model and growth mixture model. Library data from 2014 to 2019 were collected from the National Library Statistics System, and 846 public libraries were analyzed. As results, the number of circulated books were decreased, but it was tempered. Next, with controlling the factor affecting the dependent variable, the size of collection and the number of participants in reading programs provided by public libraries were statistically significant. Lastly, 5 classes were identified by applying the growth mixture model, and the number of librarians was significantly associated with trajectory class membership.

• Journal of Electrochemical Science and Technology
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• v.5 no.2
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• pp.53-57
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• 2014

With the use of diffusion-limited aggregation modeling, we have investigated the effect of particle drift for dendritic growth. It is found that the morphology of dendritic growth is sensitive to the particle drift, i.e., the larger drift effect results in the denser growth of dendrite. From the analysis using the correlation function, we found the fractional dimension of each dendrite increases as the particles drift increases. Furthermore, we showed the height of dendrite significantly decrease for the slight change of particles drift. Finally, we discussed the strategy to reduce dendritic growth by modifying the transport properties of electrolytes.

• Research in Mathematical Education
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• v.27 no.1
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• pp.129-150
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• 2024

This study utilized South Korean elementary and middle school student data to examine the longitudinal change trajectories of learning motivation types according to the longitudinal change trajectories of mathematics academic achievement. Growth mixture modeling, latent growth model, and multiple indicator latent growth model were used to examine various change trajectories for longitudinal data. As a result of the analysis, it was classified into 4 subgroups with similar longitudinal change trajectories of mathematics academic achievement, and the characteristics of the mathematics subject, which emphasize systematicity, appeared. Furthermore, higher mathematics academic achievement was associated with higher self-determination and higher academic motivation. And as the grade level increases, amotivation increases and self-determination decreases. This study suggests that teaching and learning support using this is necessary because the level of learning motivation according to self-determination is different depending on the level of mathematics academic achievement reflecting the characteristics of the student.

• Research in Community and Public Health Nursing
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• v.30 no.3
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• pp.345-356
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• 2019

Purpose: The purpose of this study is to construct and test a structural equation model of posttraumatic growth (PTG) of earthquake victims based on Tedeschi and Calhoun's model (2004). Methods: Data were collected from 195 earthquake victims living in K. City. The exogenous variables include distress perception, resilience, and social support, and the endogenous variables include intrusive rumination, deliberate rumination, and posttraumatic growth. For data analysis, descriptive statistics, factor analysis, and structural equation modeling were performed. Results: The modified model showed a good fitness to the data. Moreover, 6 of the 9 paths of the final model were statistically significant, which include PTG affected by deliberate rumination (${\beta}=.58$, p<.001), resilience (${\gamma}=.18$, p=.001), and distress perception (${\gamma}=.20$, p=.002). These predictors explain 51.8% of variance in posttraumatic growth. Conclusion: Based on the results of this study, it is necessary to develop and disseminate preventive intervention programs to increase the resilience of earthquake-prone communities. In addition, after exposure to a community-scale traumatic event such as earthquake, we should provide social supports to alleviate distress perception and transition from intrusive rumination to deliberate rumination so that we can seek new meaning from the earthquake and facilitate posttraumatic growth.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2005.10a
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• pp.626-631
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• 2005

Monitoring data from agricultural reservoirs throughout the country were analyzed to evaluate the limiting factor for algal growth and correlationship between Chl-a, total phosphorus (TP), total nitrogen (TN), and chemical oxygen demand (COD). It was used for the analysis to monitored data of 394 reservoirs such as TP, TN, Chl-a, and COD from 1999 to 2003. This study analyzed water quality items in terms of areas, seasons. It turned out that phosphorus in agricultural reservoirs (about 80%) was dominant limiting factor for algal growth. Therefor, it appears that the appropriate managements of phosphorus in the agricultural watershed are crucial to prevent excessive on algal growth. Generally, there is correlation between Chl-a and TP while Chl-a do not have effect on TN. Also, Chl-a have influence on COD. This study could be used beneficially for water quality management of agricultural reservoirs and related water quality modeling.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.40 no.4
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• pp.46-54
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• 2017

'Consulting', which is the main research topic of the knowledge service industry, is a field of study that is essential for the growth and development of companies and proliferation to specialized fields. However, it is difficult to grasp the current status of international research related to consulting, mainly on which topics are being studied, and what are the latest research topics. The purpose of this study is to analyze the research trends of academic research related to 'consulting' by applying quantitative analysis such as topic modeling and statistic analysis. In this study, we collected statistical data related to consulting in the Scopus DB of Elsevier, which is a representative academic database, and conducted a quantitative analysis on 15,888 documents. We scientifically analyzed the research trends related to consulting based on the bibliographic data of academic research published all over the world. Specifically, the trends of the number of articles published in the major countries including Korea, the author key word trend, and the research topic trend were compared by country and year. This study is significant in that it presents the result of quantitative analysis based on bibliographic data in the academic DB in order to scientifically analyze the trend of academic research related to consulting. Especially, it is meaningful that the traditional frequency-based quantitative bibliographic analysis method and the text mining (topic modeling) technique are used together and analyzed. The results of this study can be used as a tool to guide the direction of research in consulting field. It is expected that it will help to predict the promising field, changes and trends of consulting industry related research through the trend analysis.