• Journal of Wetlands Research
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• v.23 no.1
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• pp.7-13
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• 2021

Due to rapid industrial development, population growth, and improvement of living standards, the amount of sewage and wastewater, including nutrients, is increasing every year. In addition to the increasing amount of sewage and wastewater generation, untreated linked treated water (manure, livestock manure, industrial wastewater, leachate, food waste) is also increasing, and many of the linked treated water flows directly into nearby sewage treatment plants. The associated treated water causes many problems because of its own characteristics, low flow rate with high concentration compared to existing inflow sewage. In order to solve this problem, it is necessary to investigate the quantity and quality of the connected treated water whichh is flowed into the sewage treatment plant, and a study the effect on sewage treatment. Therefore, in this paper, we would like to examine the effect of the linked treated water. Seasonal effect associated with water pollution conditions was considered. In addition, a scenario was created through the distribution and inflow of connected treated water along with the water temperature conditions. Through scenario analysis, we intend to optimize the operating conditions of linked processing.

• Journal of Digital Convergence
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• v.20 no.4
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• pp.279-290
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• 2022

As the growth of the live streaming service market is accelerating due to COVID-19, the number of downloads and reviews of live streaming mobile applications is also rapidly skyrocketing. This study is to research game streaming applications using Twitch reviews as database. A total of 8 topics are extracted through LDA topic modeling and 7 out of them are detected to be inconvenience factors. Then, to pinpoint the main inconvenience factors, co-occurrence analysis is used in order to find out main factors. Finally, based on previous studies, several solutions are provided, which can solve the inconvenience factors(advertisement, UI design, technology problems) as well as strengthening digital competitiveness. This study will serve as an opportunity to improve digital competitiveness not only for Twitch but also for other game live streaming service companies in the future.

• Journal of Korea Society of Industrial Information Systems
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• v.27 no.5
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• pp.145-156
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• 2022

In recent years, as there is growing concern with ESG (Environmental, Social, and Governance), the strategic direction of business management is changing from maximizing shareholders wealth to maximizing stakeholders value. ESG is reshaping a corporation's supply chain management strategies. The purpose of this study is to explore the ESG challenges in supply chain management. As a result of network text analysis and topic modeling analysis on 3226 news articles, 'Suppliers', 'Sustainability', 'Shared Growth' 'Carbon Neutral', 'Safety and Health', 'Responsible Business Alliance', 'Supply Chain Due Diligence Law' were identified as the main issue. Since ESG initiatives in the supply chain are not limited to the efforts of individual firms, future research should focus on figuring out what difficulties and challenges exist in the diffusion of ESG practices along multi-tiered supply chains, and how to overcome them.

• International conference on construction engineering and project management
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• 2013.01a
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• pp.467-474
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• 2013

Construction contactors must continuously seek to improve their cash flows, which reside at the heart of their financial success. They require careful planning, analysis, and optimization to avoid the risk of bankruptcy, remain profitable, and secure long-term growth. Sources of cash include bank loans and retained earnings, which are conceptually similar in that they both incur a cost of capital. Financial management therefore requires accurate yet customizable modeling capabilities that can quantify all expenses, including said cost of capital. However, currently existing cash flow models in construction engineering and management have strongly simplified the manner in which interest is assessed, which may even lead to overstating it at a disadvantage to contractors. The variable nature of cash balances, especially in the early phases of construction projects, contribute to this challenging issue. This research therefore extends a new cash flow model with an accurate interest calculation. It utilizes singularity functions, so called because of their ability to flexibly model changes across any number of different ranges. The interest function is continuous for activity costs of any duration and allows the realistic case that activities may begin between integer time periods, which are often calendar months. Such fractional interest calculation has hitherto been lacking from the literature. It also provides insights into the self-referential behavior of compound interest for variable cash balances. The contribution of this study is twofold; augmenting the corpus of financial analysis theory with a new interest formula, whose strengths include its generic nature and that it can be evaluated at any fractional value of time, and providing construction managers with a tool to help improve and fine-tune the financial performance of their projects.

• Smart Media Journal
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• v.13 no.2
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• pp.95-107
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• 2024

The development of environmentally friendly products and services has become a trend, and the development and utilization of eco-friendly textiles with economic value is gaining attention as a new business model. Analyzing and identifying trends and developments in eco-friendly textiles can provide important information and insights for various stakeholders such as companies, governments, and consumers to help them achieve sustainable growth. For this study, we collected and analyzed data from newspaper articles mainly covering the textile and fashion sector from 2000 to June 2023. A total of 12,331 articles containing the keyword 'eco-friendly textiles' were collected, and after performing morphological analysis on the extracted data, Latent Dirichlet Allocation and Dynamic Topic Modeling analysis were performed to identify topics by year. The results of the study are expected to provide strategic guidance and insights for the sustainable development of the textile industry, thereby helping to promote the research, development, and commercialization of eco-friendly textiles.

• Food Science of Animal Resources
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• v.33 no.2
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• pp.155-161
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• 2013

This study developed predictive models to evaluate the kinetic behaviors of Bacillus cereus and Staphylococcus aureus in milk during storage at various temperatures. B. cereus and S. aureus (3 Log CFU/mL) were inoculated into milk and stored at $10^{\circ}C$, $15^{\circ}C$, $20^{\circ}C$, and $30^{\circ}C$, as well as $5^{\circ}C$, $15^{\circ}C$, $25^{\circ}C$, and $35^{\circ}C$, respectively, while bacterial populations were enumerated. The growth data were fitted to the modified Gompertz model to estimate kinetic parameters, including the maximum specific growth rate (${\mu}_{max}$; Log CFU/[$mL{\cdot}h$]), lag phase duration (LPD; h), lower asymptote ($N_0$; Log CFU/mL), and upper asymptote ($N_{max}$; Log CFU/mL). To describe the kinetic behavior of B. cereus and S. aureus, the parameters were fitted to the square root model as a function of storage temperature. Finally, the developed models were validated with the observed data, and Bias (B) and Accuracy (A) factors were calculated. Cell counts of both bacteria increased with storage time. Primary modeling yielded the following parameters; ${\mu}_{max}$: 0.14-0.75 and 0.06-0.51 Log CFU/mL/h; LPD: 1.78-14.03 and 0.00-1.44 h, $N_0$: 3.10-3.37 and 2.09-3.07 Log CFU/mL, and $N_{max}$: 7.59-8.87 and 8.60-9.32 Log CFU/mL for B. cereus and S. aureus, respectively. Secondary modeling yielded a determination of coefficient ($R^2$) of 0.926.0.996. B factors were 1.20 and 0.94, and A factors were 1.16 and 1.08 for B. cereus and S. aureus, respectively. Thus, the mathematical models developed here should be useful in describing the kinetic behaviors of B. cereus and S. aureus in milk during storage.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.10
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• pp.509-519
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• 2016

This study intends to examine how the subjective health perception of drinkers influences the depression trajectory change by using longitudinal data for elderly drinkers. This study has set up a balanced panel by combining the results from "Aging study panel research" conducted in the year 2006 (1st), 2008 (2nd), 2010 (3rd), 2012 (4th). A total of 543 elderly drinkers, who have responded to each research have been selected as targets for the final analysis. In the analyses, descriptive statistics and Latent Growth Modeling were conducted to examine the causal relationship between the observed and latent variables. The results are as follows: First, it was found that there was a negative correlation-with statistical significance-between the initial value of subjective health perception and the initial status of depression symptom. Second, there was a positive correlation between the initial value of subjective health perception and the changes of depression symptom. This indicates that elderly drinkers with high health perception usually have high degree of depression change; however, this does not mean it was statistically significant. Third, there was a statistically significant correlation between subjective health perception change and depression symptom change. It was found that the depression change level would be low if the subjective health perception change level was high. Thus, we can assume that the depression symptoms of elderly drinker c would slow down if the subjective health perception level increases.

• 한국노년학
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• v.37 no.3
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• pp.727-745
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• 2017

This study purported to examine the effects of precarious employment and social capital on the changes of self-rated health status among the middle aged and the young-old population in South Korea. The study analyzed 12 year follow-up data generated by the Korean Labor and Income Panel Study(KLIPS 6-17), which included 10532 employed subjects aged 55 to 75. Multi-level growth curve modeling was performed by fixed and random effect models using STATA 13.0 program. Afterwards, Hausman test was performed, which resulted in support of the estimation by fixed effect model. The results showed that a day labor position was significant factor affecting the deteriorated changes of self-rated health status over time. In addition, wage, weekly working hours, and private/relational social capitals were also found to be significant factors affecting the changes of the self-rated health status. The results supported the divergence hypothesis as well as the cumulative advantage theory. Efforts should be made to develop and implement various employment support policies and social service programs to alleviate the health inequality of the employed workers over their middle-aged to young-old period.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.33 no.1
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• pp.22-30
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• 2023

Currently, almost all product development in the jewelry industry utilizes 3D CAD and 3D printing. In this situation, 3D CAD modeling and 3D printing ability units in colleges, Tomorrow Learning Card Education, and Course Evaluation-type jewelry design related education are conducted with developed curriculum based on the standards for training standards, training hours, training equipment, and practice materials presented by NCS. Accordingly, this study analyzes 3D CAD modeling and 3D printing training facilities, training hours, training equipment, etc into three categories of NCS precious metal processing and jewelry design, and studies the development of educational systems such as 3D CAD/3D printing curriculum and various environments that meet these standards. Education using this 3D CAD/3D printing education system will enable us to continuously supply professional talent with practical skills not only in the jewelry industry but also in the entire 3D CAD/3D printing manufacturing industry, which is called as one of the pillars of the 4th Industry. The quality of employment of trainees receiving education and the long-term retention rate after employed can also have a positive effect. In addition, excellent educational performance will help improve the recruitment rate of new students in jewelry jobs or manufacturing-related departments, which are difficult to recruit new students in recent years.

• 한국노년학
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• v.29 no.4
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• pp.1611-1628
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• 2009

It is well known that health and psychosocial factors are closely associated with depressive symptoms. Due to limitations in available data and analysis methods, however, little is known about the effects of health and psychosocial factors on depression trajectory. In order to address the limitations, this study examines the predictors of depression trajectory using latent growth curve modeling involving individuals aged 60 and over who participated in the Korean Welfare Panel Study (N=4,919). Controlling for socioeconomic variables, health and psychosocial variables were cross-sectionally associated with depressive symptoms, which is consistent with previous findings. However, the effects of health and psychosocial variables on the rate of depressive symptom change varied. Health variables were significantly associated with the levels of depressive symptoms at wave 1, but these were not significantly associated with the rate of depressive symptoms change. By contrast, although psychosocial variables were significantly associated with depressive symptoms at wave 1, the effects of psychosocial variables on the rate of depressive symptom change varied. Specifically, while self-esteem and family relationship were positively associated with the rate of depressive symptom change, social relationship was negatively associated with the rate of depressive symptom change. Based on the findings, this study discussed implications for intervention and future research.