• Journal of dental hygiene science
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• v.24 no.2
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• pp.97-106
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• 2024

Background: Periodontitis and peri-implantitis are diseases caused by pathogenic microorganisms that cause tissue damage and alveolar bone destruction resulting in the loss of teeth and implants. Due to the biological differences in the tissues surrounding the implants, peri-implantitis progresses more rapidly and intensely than periodontitis, underscoring the importance of understanding the characteristics and interactions of pathogenic bacteria. This study aimed to quantitatively analyze the pathogenic microorganisms associated with periodontitis and peri-implantitis in Korean patients and evaluate the correlation between these bacteria. Methods: A total of 98 (52 males and 46 females) were randomly selected and classified into three groups (healthy group [HG]=25; periodontitis group [PG]=31; and peri-implantitis group [PIG]=42). The relative expression levels of 11 pathogenic microorganisms collected from the gingival sulcus fluid were determined using multiplex real-time polymerase chain reaction. Results: Eikenella corrodens, Fusobacterium nucleatum, and Prevotella nigrescens were highly prevalent in the HG, PG, and PIG patients. The results of the relative quantitative analysis of microorganisms showed that all bacteria belonging to the green, orange, and red complexes were significantly more abundant in the PG and PIG than in the HG (p<0.05). Porphyromonas gingivalis in the red complex showed a positive correlation with all microorganisms in the orange complex (p<0.05). Campylobacter rectus in the orange complex showed a significant positive correlation with all microorganisms in the red complex, and with F. nucleatum, P. nigrescens, Prevotella intermedia, and Eubacterium nodatum (p<0.05). Conclusion: P. gingivalis, C. rectus, and F. nucleatum exhibit strong interactions. Removing these bacteria can block complex formation and enhance the prevention and treatment of periodontitis and peri-implantitis.

• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.4
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• pp.31-39
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• 2010

Although driving patterns strongly influence greenhouse gas and air pollutant emission rate from light duty vehicles, emission measurements have been mainly based on chassis dynamometer testing with one standard driving pattern. And there has been limited work on quantifying the independent effect of driving parameters on emission rate because of multidimensional nature of real-world driving pattern. The objective of this study is to obtain the quantitative effect of relative positive acceleration (RPA) on vehicle emission rate. RPA has been used to define the occurrence of acceleration demanding large amounts of power in certain driving distance and shown to be a significant affecting parameter for real-world emission rate. 40 driving patterns have been developed with fixed driving parameters to investigate independent effect of RPA. For the same values of average vehicle speed and power, the trend in carbon dioxide emission rate and fuel consumption with respect to RPA is very clear. Emission rate of nitrogen oxide and particulate matter also increase with respect to RPA, but the trend is less clear. Carbon dioxide emission from diesel vehicle appear to be more affected by high accelerations compared to that from gasoline vehicle because of high intake air restriction during acceleration caused by turbocharger and intercooler. The results have implications for the possible reduction of environmental effects through better traffic planning and management, driver education and car design.

• Journal of Biomedical Engineering Research
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• v.25 no.4
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• pp.235-242
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• 2004

In this paper, we proposed the algorithm for detection of microtalcification by automatic threshold decision based on region growing method. The region for optimal threshold is grown from local maximum pixel by increasing repeatedly threshold in microralcification candidate region. Then, the optimal threshold is automatically decided at the maximum value of the contrast and edge sharpness in this region. Microcalcifications could be efficiently detected as satisfied result that true positive ratio is 81.5% and average false positive numbers are 1.1 about total 299 microcalcifirations in real image. In a result, we showed that this algorithm can be used to aid diagnostic-radiologist for the diagnosis of the early phase of breast cancer.

• The Transactions of the Korean Institute of Power Electronics
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• v.27 no.5
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• pp.410-416
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• 2022

A grid-connected inverter with critical loads uses mode transfer control to supply stable voltage to the load. An islanding detection method should also be used to quickly detect the grid fault and disconnect the inverter from the grid. However using the existing islanding detection method to detect islanding is difficult due to the small fluctuation of the voltage and frequency of the point of common coupling. This study proposes a reactive power P&O islanding detection method by using the positive feedback technique. The proposed method always injects a small variation of reactive power. When a grid fault occurs, the injected reactive power accelerates the reactive power injection reference. As a result, the reactive power reference value and the sensed reactive power become mismatched, and islanding is detected. Reducing the amount of real-time injected reactive power results in high efficiency and power factor. The simulation and experimental results of a 3 kW single-phase inverter are provided to verify the proposed islanding detection method.

• The Journal of Economics, Marketing and Management
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• v.11 no.3
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• pp.11-23
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• 2023

Purpose: This study empirically studied the effects of the perceived value of education and training on SME cooperative on job performance. Research design, data and methodology: From November 7 to 9, 2022, a survey was conducted targeting members and executives of SME cooperatives in their 20s and 60s across the country, and a total of 217 people were used for the final analysis. Verification of the research model was performed using SPSS & AMOS. Frequency analysis was conducted to examine the sample characteristics. Results: First, perceived value (functional value, service performance value, emotional value, convenience value) did not have a significant effect on organizational commitment. Second, perceived value (functional value, service performance value, emotional value, convenience value) were found to have a significant positive (+) effect on job satisfaction. Third, job satisfaction was found to have a significant positive (+) effect on organizational commitment. Fourth, organizational commitment was found to have a significant positive (+) effect on job performance. Fifth, job satisfaction was found to have a significant positive (+) effect on job performance. Conclusions: These results suggest that the perceived value of SME cooperative education and training can affect organizational commitment and job performance through job satisfaction, so it is necessary to strengthen online education and training to meet the emotional response of training subjects along.

• Journal of Distribution Science
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• v.21 no.10
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• pp.11-19
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• 2023

Purpose: Personality qualities are essential to the prosperity of any contemporary company because they foster the growth of pleasant emotions in telecommunications distribution employees. Research design, data and methodology: Thus improving their overall psychological well-being and productivity. Talent retention is facilitated by mutual respect between management and staff. The success of the company as a whole, including the development and maintenance of emotions with customers, also depends on the psychological well-being of employees. The aim is to demonstrate how a positive and satisfied emotional workforce contributes to psychological well-being in the 21st century. Result: The research aims to better understand the personality traits that influence the psychological well-being of employees. In addition, between January and March 2023, a total of 179 employees in the telecommunications distribution industry in the Peruvian city of Chiclayo were surveyed using structural modelling methods to measure employee satisfaction. It also shows how various ideas, approaches and models can be used in the real world. Conclusion: The significance of the model on the perception of telecommunications workers in Peru is demonstrated by the results, which indicate an R² value of 0.681 for positive emotions and an R² value of 0.792 for employees' psychological well-being.

• The Journal of Economics, Marketing and Management
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• v.11 no.5
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• pp.29-44
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• 2023

Purpose: This study analyzed the effect of the perceived value of the OTT platform on consumers' technology acceptance, continuous use intention, and WOM using the Expanded TAM. Research design, data and methodology: A survey was conducted targeting OTT platform users in their 20s to 40s nationwide from August 10 to 16, 2022, and a total of 208 people were used in the final analysis. To verify the research model, frequency analysis, CFA, and SEM analysis were performed using SPSS and AMOS. Results: First, the perceived value of the OTT platform was found to have a positive effect on consumers' technology acceptance (perceived usefulness, perceived ease of use, and perceived enjoyment). Second, the perceived ease of use of OTT platform consumers was found to have a positive effect on perceived usefulness and perceived enjoyment. Third, it was found that the perceived usefulness and perceived enjoyment of OTT platform consumers had a positive effect on the continuous use intention, and WOM. Fourth, it was found that the continuous use intention the OTT platform had a positive effect on the WOM. Conclusions: Word of mouth and continuous use of existing customers are important for OTT platform companies to retain existing customers and secure new customers. Through the perceived value of the OTT platform, efforts should be made to provide various contents that consumers can enjoy along with usefulness and convenience of functions.

• Korean Journal of Microbiology
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• v.47 no.1
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• pp.87-91
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• 2011

The aim of this study was to compare the performance of conventional culture and real-time PCR for detection of Cronobacter spp. in powdered foods. Infant formula, baby food and Misugaru inoculated with Cronobacter were enriched in distilled water as first enrichment step, followed by incubating in Enterobacteriaceae enrichment (EE) broth as second enrichment step. A loopful of enriched sample was streaked onto Druggan-Forsythe-Iversen agar, followed by incubating at $37^{\circ}C$ for 24 h. One milliliter of the enriched distilled water and EE broth were used in real-time PCR assay. No statistical differences were observed in the number of positive samples between culture method and real-time PCR (p>0.05) in all types of food samples. The number of positives of real-time PCR was higher in the first enrichment media (distilled water) than the second enrichment media (EE broth), though there was no significant difference (p>0.05). It appears that some components of the second enrichment broth, EE broth, inhibit the reaction of real-time PCR. These results show that real-time PCR using a single enrichment with distilled water could be useful as an effective screening method for detection of Cronobacter while saving much time and labor compared to conventional culture method.

• Journal of the Korean Society of Systems Engineering
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• v.20 no.1
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• pp.50-63
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• 2024

This study analyzed the relationships between positive attitude, leisure attitude, and leisure satisfaction among university students participating in a leisure activity support education program using the metaverse. The results are as follows. First, positive attitude was found to have a significant impact on leisure attitude. Perspective diversification influenced the cognitive and emotional factors of leisure attitude, self-acceptance influenced the emotional factor, and social adaptation influenced both the cognitive and emotional factors. Second, leisure attitude was found to have a significant impact on leisure satisfaction. Cognitive and emotional attitudes influenced all factors of leisure satisfaction, while behavioral attitude primarily influenced the relaxation factor. Third, positive attitude was found to have a significant impact on psychological, social, relaxation, and physiological factors of leisure satisfaction. Perspective diversification and self-acceptance played important roles, while social adaptation influenced all factors of leisure satisfaction. These findings provide important implications for the curriculum design of leisure activity support education programs using the metaverse for university students, focusing on enhancing positive attitude. The metaverse environment offers experiences similar to real-life interactions, which can contribute to enhancing participants' positive attitude and improving their leisure satisfaction. Program design should include elements that enhance participants' self-acceptance and social adaptation abilities, as well as focus on improving self-regulation skills. Through this, university students can enrich their leisure experiences, ultimately contributing to improving their overall quality of life.

• Journal of the Economic Geographical Society of Korea
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• v.6 no.1
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• pp.211-231
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• 2003

In this study, first, current state and future prospects of indirect real estate investment systems after foreign exchange crisis are analyzed, and second, policy alternatives for activating indirect real estate investment markets are examined. After foreign exchange crisis, various indirect real estate investment systems, such as REITs, ABS and CRC, were introduced. Present market size of indirect real estate investment is not larger than expected. The reasons are the problems of incomplete system on the one hand, and real estate market conditions on the other hand. But long term prospects of indirect real estate investment markets may not be pessimistic. Considering the positive effects of indirect real estate investment systems to the real estate and financial markets, policy supports for activating indirect real estate investment market may be needed. The representative alternatives are reconciliation and integration of indirect real estate investment systems, upgrading the infrastructure of real estate industry, and activating the networks between indirect real estate investment markets and related markets such as financial makets, capital markets, restructuring markets.