• Journal of Microbiology and Biotechnology
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• 제25권11호
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• pp.1842-1848
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• 2015

Cyanidin-3-glucoside (C3G) has been known to be more bioavailable than cyanidin-3-rutinoside (C3R), the most abundant anthocyanin in black raspberry (Rubus occidentalis). The aim of this study was to enhance the bioavailability of anthocyanins in black raspberry by cleaving ʟ-rhamnose in C3R using crude enzyme extracts (CEEs) from Aspergillus usamii KCTC 6956, A. awamori KCTC 60380, A. niger KCCM 11724, A. oryzae KCCM 12698, and A. kawachii KCCM 32819. The enzyme activities of the CEEs were determined by a spectrophotometric method using ρ-nitrophenyl-rhamnopyranoside and ρ-nitrophenyl-glucopyranoside. The CEE from A. usamii had the highest α-ʟ-rhamnosidase activity with 2.73 U/ml at 60℃, followed by those from A. awamori and A. niger. When bioconversion of C3R to C3G in black raspberry was analyzed by HPLC-DAD, the CEEs from A. usamii and A. awamori hydrolyzed 95.7% and 95.6% of C3R to C3G, respectively, after 2 h incubation. The CEEs from A. kawachii and A. oryzae did not convert C3R to C3G in black raspberry.

• The Journal of Asian Finance, Economics and Business
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• 제7권3호
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• pp.149-156
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• 2020

The study aims to investigate a close relation between macro and non-macro variables on stock performance of tourism companies in Korea. The sample used in this study includes monthly data from January 2001 to December 2018. The stock price index of the tourism companies as a dependent variable are obtained from Sejoong, HanaTour, and RedcapTour as three leading Korean tourism companies that have been listed on the Korea Stock Exchange. This study assesses the tourism stock performance using the quantile regression approach. This study also investigates whether global crisis events as the Iraq War and the global financial crisis as non-macro variables have a significant effect on the stock performance of tourism companies in Korea. The results show that the oil prices, exchange rate and industrial production have negative coefficients on stock prices of tourism companies, while the effects of tourist expenditure and consumer price index are positive and significant. We estimate the result of quantile regression that non-macro determinants have statistically a significant and negative effect on tourism stock performance because the global crisis could threaten traveler's safety and economy. Overall, empirical results suggest that the effects of macro and non-macro variables are statistically asymmetric and highly related to tourism stock performance.

• Journal of Species Research
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• 제6권1호
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• pp.25-41
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• 2017

As a subset study for the collection of Korean indigenous prokaryotic species, 62 bacterial strains belonging to the phylum Actinobacteria were isolated from various sources. Each strain showed higher 16S rRNA gene sequence similarity (>98.75%) and formed a robust phylogenetic clade with closest species of the phylum Actinobacteria which were defined with valid names, already. There is no official description on these 62 actinobacterial species in Korea. Consequently, unrecorded 62 species of 25 genera in the 14 families belonging to the order Actinomycetales of the phylum Actinobacteria were found in Korea. Morphological properties, basic biochemical characteristics, isolation source and strain IDs are described in the species descriptions.

• 한국학교보건학회지
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• 제31권1호
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• pp.29-38
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• 2018

Purpose: The purpose of this study is to investigate the mediator effect of major satisfaction in relation to depression and job-seeking stress of university students according to the majors. Methods: This descriptive study was conducted in three universities randomly chosen from 47 universities in Seoul, Korea. Participants were 241 undergraduate students who were eligible and agreed to participate in the study. Data were collected from October 27 to November 10, 2014. The data were analyzed with descriptive statistics, $x^2$ test, Fisher's exact test, t-test, Kruskal-Wallis test, Pearson correlation coefficients, simple and multiple regression techniques with the PASW/WIN 20.0 program. Results: There were significant negative, negative, and positive correlations between job-seeking stress and major satisfaction, major satisfaction and depression, and job-seeking stress and depression regardless of major field, respectively. Moreover, in the major group in natural science and engineering, the link between job-seeking stress and depression was partially mediated by major satisfaction. Conclusion: The findings of this study contribute to providing basic data for the development of job-seeking stress and depression intervention programs and future study for university students.

• ETRI Journal
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• 제35권6호
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• pp.1058-1067
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• 2013

An approach for game bot detection in massively multiplayer online role-playing games (MMORPGs) based on the analysis of game playing behavior is proposed. Since MMORPGs are large-scale games, users can play in various ways. This variety in playing behavior makes it hard to detect game bots based on play behaviors. To cope with this problem, the proposed approach observes game playing behaviors of users and groups them by their behavioral similarities. Then, it develops a local bot detection model for each player group. Since the locally optimized models can more accurately detect game bots within each player group, the combination of those models brings about overall improvement. Behavioral features are selected and developed to accurately detect game bots with the low resolution data, considering common aspects of MMORPG playing. Through the experiment with the real data from a game currently in service, it is shown that the proposed local model approach yields more accurate results.

• 대한치과교정학회지
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• 제42권5호
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• pp.249-254
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• 2012

Objective: To investigate the stem cell-like characteristics of human periodontal ligament (PDL) stromal cells outgrown from orthodontically extracted premolars and to evaluate the potential for myogenic differentiation. Methods: PDL stromal cells were obtained from extracted premolars by using the outgrowth method. Cell morphological features, self-replication capability, and the presence of cell-surface markers, along with osteogenic, adipogenic, and chondrogenic differentiation, were confirmed. In addition, myogenic differentiation was induced by the use of 5-aza-2'-deoxycytidine (5-Aza) for DNA demethylation. Results: PDL stromal cells showed growth patterns and morphological features similar to those of fibroblasts. In contrast, the proliferation rates of premolar PDL stromal cells were similar to those of bone marrow and adipogenic stem cells. PDL stromal cells expressed surface markers of human mesenchymal stem cells (i.e., CD90 and CD105), but not those of hematopoietic stem cells (i.e., CD31 and CD34). PDL stromal cells were differentiated into osteogenic, adipogenic, and chondrogenic lineages. Myotube structures were induced in PDL stromal cells after 5-Aza pretreatment, but not in the absence of 5-Aza pretreatment. Conclusions: PDL stromal cells isolated from extracted premolars can potentially be a good source of postnatal stem cells for oromaxillofacial regeneration in bone and muscle.

• 한국추진공학회지
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• 제23권6호
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• pp.87-94
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• 2019

본 논문에서는 P&WC 사 PT6A-67A 엔진의 연료 필터 오염에 대한 원인 탐구를 수행했다. 관련하여 PT6A-67A 엔진 연료 필터 오염 개요와 엔진 공급라인 구성에 대해서 명시했다. 다음으로, 분석방법을 공급 연료 성분 분석과 고형 침전물 분석(EDX, TGA, 광학현미경)으로 분류하여 비교분석했다. 결과들을 종합하면, 검출된 주요 성분은 연료 탱크 실런트의 황 성분이었다. 이 결과들의 후속조치로서 P&WC와 국방과학연구소는 엔진 운용에 있어서 엔진 연료 필터 주기 점검 및 연료 탱크 세척을 수행할 예정이다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권3호
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• pp.1533-1556
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• 2017

The concept of trust in vehicular ad hoc networks (VANETs) is usually utilized to assess the trustworthiness of the received data as well as that of the sending entities. The quality of safety applications in VANETs largely depends on the trustworthiness of exchanged data. In this paper, we propose a self-organized distributed trust computing framework (DTCF) for VANETs to compute the trustworthiness of each vehicle, in order to filter out malicious nodes and recognize fully trusted nodes. The proposed framework is solely based on the investigation of the direct experience among vehicles without using any recommendation system. A tier-based dissemination technique for data messages is used to filter out non authentic messages and corresponding events before even going farther away from the source of the event. Extensive simulations are conducted using Omnet++/Sumo in order to investigate the efficiency of our framework and the consistency of the computed trust metrics in both urban and highway environments. Despite the high dynamics in such networks, our proposed DTCF is capable of detecting more than 85% of fully trusted vehicles, and filtering out virtually all malicious entities. The resulting average delay to detect malicious vehicles and fraudulent data is showed to be less than 1 second, and the computed trust metrics are shown to be highly consistent throughout the network.

• 재활간호학회지
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• 제19권1호
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• pp.64-70
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• 2016

Purpose: The purpose of this study was to identify awareness and knowledge about hepatitis B virus (HBV) infection among North Korean immigrants who had resided in South Korea. Methods: This was a cross-sectional, community based study. Data were collected from a convenience sample of 198 North Korean immigrants aged 18 years old through 65 years old among those who had attended community centers, local churches, and gathering places in four cities. The questionnaire included 15 items about participants' knowledge on HBV infection and its consequences, mode of transmission, and preventive measures. Results: The mean score of HBV knowledge was $6.3{\pm}3.8$ (range 0~15). The items that over 60% of the respondents checked correct answer regarding knowledge about HBV were 'There is blood screening for hepatitis B infection', 'Hepatitis B can be transmitted through sharing needles with infected person'. Multivariate analysis showed that received education for the prevention of HBV infection and disease morbidity were significantly associated with the knowledge of HBV infection. Overall, approximately 11% of total variability in the knowledge of HBV infection could be explained by the 2 variables in this model ($R^2=.109$, p<.001). Conclusion: The results showed that North Korean immigrants need more education on HBV infection and prevention to improve their knowledge about HBV.

• 아동학회지
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• 제36권2호
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• pp.167-182
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• 2015

This study created a structural model of the influence of paternal and maternal meta-emotion philosophy and children's emotion regulation in terms of their social competence and confirmed the nature of the relationship among the variables. For the purpose of this study, data was collected, targeting 363 children in the $5^{th}$ and $6^{th}$ elementary school grades from schools located in Seoul. The main results of this study were as follows: First, both paternal and maternal meta-emotion philosophy had an influence on children's emotion regulation and emotion dysregulation. Next, paternal and maternal meta-emotion philosophy did not appear to have a significant influence on children's social competence in a direct manner. The complete mediation effect of emotion regulation in regards to the influence of paternal and maternal meta-emotion philosophy upon children's social competence was confirmed. It was also found that parental meta-emotion philosophy had an influence upon children's social competence in an indirect manner through children's emotion regulation in the period of middle childhood.