• Proceedings of the Microbiological Society of Korea Conference
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• 2000.05a
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• pp.23-36
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• 2000

Japanese encephalitis virus (JEV) is the causative agent of a mosquito-borne encephalitis and is transmitted to human via persistently infected mosquito vectors. Although the virus is known to cause only acute infection, there were reports that showed neurological sequelae, latent infection in peripheral mononuclear cells, and recurrence of the disease after acute encephalitis. Innate resistance of certain cell lines, abnormal SN1 expression of the virus, and anti-apoptotic effect of cullular bcl-2 have been suggested as probable causes of JEV persistence even in the absence of defective interfering (DI) particles. Although possible involvement of DI particles in JEV persistence was suggested, neither has a direct evidence for DI presence nor its molecular characterization been made. Two questions asked in this study are whether the DI virus plays any role in JEV persistent infection if it is associated with and what type of change(s) can be made in persistently infected cells to avoid apoptosis even with the continuous virus replication, DI-free standard stock of JEV was infected in BHK-21, Vero, and SW13 cells and serial high multiplicity passages were performed in order to generate DI particles. There different-sized DI RNA species which were defective in both structural and nonstructural protein coding genes. Rescued ORFs of the DI genome maintained in-frame and the presence of replicative intermediate or replicative form RNA of the DI particles confirmed their replication competence. On the other hand, several clones with JEV persistent infection were established from the cells survived acute infections during the passages. Timing of the DI virus generation during the passages seemed coincide to the appearance of persistently infected cells. The DI RNAs were identified in most of persistently infected cells and were observed throughout the cell maintenance. One of the cloned cell line maintained the viral persistence without DI RNA coreplication. The cells with viral persistence released the reduced but continuous infectious JEV particle for up to 9 months and were refractory to homologous virus superinfection but not to heterologous challenges. Unlike the cells with acute infection these cells were devoid of characteristic DNA fragmentation and JEV-induced apoptosis with or without homologous superinfection. Therefore, the DI RNA generated during JEV undiluted serial passage on mammalian cells was shown to be biologically active and it seemed to be responsible, at least in part, for the establishment and maintenance of the JEV persistence in mammalian cells. Viral persistence without DI RNA coreplication, as in one of the cell clones, supports that JEV persistent infection could be maintained with or without the presence of DI particles. In addition, the fact that the cells with JEV persistence were resistant against homologous virus superinfection, but not against heterologous one, suggests that different viruses have their own and independent pathway for cytopathogenesis even if viral cytopathic effect could be converged to an apoptosis after all.

• The Korean Journal of Physiology and Pharmacology
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• v.17 no.3
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• pp.223-228
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• 2013

The calcium-activated $K^+$ ($BK_{Ca}$) channel is one of the potassium-selective ion channels that are present in the nervous and vascular systems. $Ca^{2+}$ is the main regulator of $BK_{Ca}$ channel activation. The $BK_{Ca}$ channel contains two high affinity $Ca^{2+}$ binding sites, namely, regulators of $K^+$ conductance, RCK1 and the $Ca^{2+}$ bowl. Lysophosphatidic acid (LPA, 1-radyl-2-hydroxy-sn-glycero-3-phosphate) is one of the neurolipids. LPA affects diverse cellular functions on many cell types through G protein-coupled LPA receptor subtypes. The activation of LPA receptors induces transient elevation of intracellular $Ca^{2+}$ levels through diverse G proteins such as $G{\alpha}_{q/11}$, $G{\alpha}_i$, $G{\alpha}_{12/13}$, and $G{\alpha}s$ and the related signal transduction pathway. In the present study, we examined LPA effects on $BK_{Ca}$ channel activity expressed in Xenopus oocytes, which are known to endogenously express the LPA receptor. Treatment with LPA induced a large outward current in a reversible and concentration-dependent manner. However, repeated treatment with LPA induced a rapid desensitization, and the LPA receptor antagonist Ki16425 blocked LPA action. LPA-mediated $BK_{Ca}$ channel activation was also attenuated by the PLC inhibitor U-73122, $IP_3$ inhibitor 2-APB, $Ca^{2+}$ chelator BAPTA, or PKC inhibitor calphostin. In addition, mutations in RCK1 and RCK2 also attenuated LPA-mediated $BK_{Ca}$ channel activation. The present study indicates that LPA-mediated activation of the $BK_{Ca}$ channel is achieved through the PLC, $IP_3$, $Ca^{2+}$, and PKC pathway and that LPA-mediated activation of the $BK_{Ca}$ channel could be one of the biological effects of LPA in the nervous and vascular systems.

• Resources Recycling
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• v.11 no.6
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• pp.3-11
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• 2002

Recently, waste printed circuit board (PCB) has significantly increased in its amount due to the rapid development of electronic industries. Since several kinds of noxious materials and also valuable metals are contained in it, the waste PCB is in an urgent need of recycling for the dual purposes for the prevention of environmental pollution and recovery of valuable resources. Also, the catalyst which equipped in the exhaust pipes of automobiles to reduce emission of air pollutants contains precious met-als so that their recovery from the waste auto-catalysts is required. In this study, the recovery of valuable metals from waste PCB and auto-catalyst by arc furnace melting process has been investigated, which is known to be very stable and suitable f3r less production of pollutants due to its high operating temperature. The effect of the kind of flux on the recovery of precious metals was examined by using quicklime, converter slag, and copper slag as the flux. In addition, the influence of direct and alternating current and the applying direction of direct current has been investigated. It was observed that using converter or copper slag as a flux was more desirable for a higher efficiency in the precious metal recovery compared with quicklime. For the effect of current, application of direct current taking the bottom as a negative pole generally showed a better efficiency for the extraction of valuable metals from waste PCB, which was also observed for the case of waste auto-catalyst. The average recovery of precious metals from both wastes by arc furnace melting process was very high, which was up to in the range of 95～97%.

• Journal of Intelligence and Information Systems
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• v.13 no.1
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• pp.59-79
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• 2007

P2P (Peer to Peer) techniques have been well applied to file sharing due to its cost-effectiveness and convenience. Dynamic network evolution is another good thing for P2P according to addition and deletion of nodes and change of files a node has. Our research proposes a P2P-based KMS (Knowledge Management System). Knowledge of enterprises spreads all over sub-organizations like oversea factories and sales departments and is changed in dynamic manner. P2P techniques are, therefore well matched with knowledge management domain. In order to increase search efficiency, we introduce social network theory into P2P-based KMS. Social network technique makes the most similar nodes (in KMS domain, nodes which has the most similar knowledge) its own neighbors, which makes eventually search efficiency increase. We developed our prototype system P2P-SN-KMS and evaluated by simulation.

• Korean Security Journal
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• no.42
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• pp.277-308
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• 2015

Recently the Japanese hostage crisis with Syria, the stake of the pilots IS of the terror group's affiliates like Kim incident occurred while urinarado IS not an exception anymore in connection with terrorism will not be able to do. In addition, particularly against terrorist groups worldwide, IS being a hero has been marginalized and wants uncritical drugs aimed at teens, such as dialog or game IS through SNS joined nationals as well as other countries, while recommending domestic complaints until the people power or luck, put the older brother can sign up for any terror group IS the terrorist group's terrorist acts while making the environment a national mark by foreigners or immigrants can be caused by the situation. Therefore, in this study, this IS serious for the terrorist acts of the terrorist group, IS due to the expansion of the domestic terrorist group caused the terror raids of about the dangers of foreign countries to review the case, and the incident has sought ways to prevent and respond to the rapporteur. The result IS due to the expansion of the domestic terrorist group caused the terror raids of the dangers of sex exists and that causes a response to the implements are as follows. First of all, IS brokering for the site of the terrorist group's approach to counter-terrorism Act will be a, and the next, each agency and terror for the information exchange and cooperation and serves as a reexamination of terror occurred through the quick and appropriate measures should be the language. Finally, the duties related to terrorism for teens, especially education and strengthen the safety program development and against terrorism should be carried out.

• Journal of Internet Computing and Services
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• v.20 no.3
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• pp.43-59
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• 2019

Today, with the spread of smartphones and the development of social networking services, structured and unstructured big data have stored exponentially. If we analyze them well, we will get useful information to be able to predict data for the future. Large amounts of data need to be collected first in order to analyze big data. The web is repository where these data are most stored. However, because the data size is large, there are also many data that have information that is not needed as much as there are data that have useful information. This has made it important to collect data efficiently, where data with unnecessary information is filtered and only collected data with useful information. Web crawlers cannot download all pages due to some constraints such as network bandwidth, operational time, and data storage. This is why we should avoid visiting many pages that are not relevant to what we want and download only important pages as soon as possible. This paper seeks to help resolve the above issues. First, We introduce basic web-crawling algorithms. For each algorithm, the time-complexity and pros and cons are described, and compared and analyzed. Next, we introduce the state-of-the-art web crawling algorithms that have improved the shortcomings of the basic web crawling algorithms. In addition, recent research trends show that the web crawling algorithms with special purposes such as collecting sentiment words are actively studied. We will one of the introduce Sentiment-aware web crawling techniques that is a proactive web crawling technique as a study of web crawling algorithms with special purpose. The result showed that the larger the data are, the higher the performance is and the more space is saved.

• Journal of Mushroom
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• v.17 no.3
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• pp.167-170
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• 2019

Cultivation of brown mushrooms, rather than that of white variants is preferred by Korean mushroom farmers, as the former are resistant to diseases. However, brown mushrooms were cultivated only in selective eco-friendly agricultural farms due to lack of consumer awareness. After providing information about brown mushrooms to respondents through a 1-minute video clip, a survey was conducted on social network service (SNS) to assess recognition and preference for brown mushrooms. A food evaluation was then conducted among 200 people randomly selected from the survey respondents. Most respondents (83%) had not encountered brown button mushrooms previously, and 98% of the respondents were willing to buy these mushrooms because they were "curious about its taste" (44%). In the food evaluation, 32% of the respondents found the brown button mushrooms to be delicious, 28% reported a good flavor, and 31% described a good texture. In addition, we confirmed that 95% of respondents were interested in purchasing brown mushrooms after sampling. Therefore, in the present study, we evaluated public perception, preference, and taste of brown button mushrooms, and confirmed that availability of information on nutrition and benefits s of mushroom consumption could induce consumers to buy brown button mushrooms.

• Journal of the Korea Convergence Society
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• v.12 no.2
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• pp.163-171
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• 2021

The purpose of this study is to examine the current operation condition of fashion start-up companies and the characteristics of their founders in Fashion Creative Studio that is one of government programs supporting fashion start-up of rising fashion designer's brands in Korea and one of supporting facilities. For this purpose, this study surveyed 32 fashion start-up companies founders in Busan Fashion Creative Studio and analyzed the data based on the survey. The results are as follows. First of all, 82% of the founders have experience to start their business in 20s and 60% of founders with not more than 3 to 5 years of work experience related to fashion challenge to start a business. Secondly, major distribution channels of the fashion start-up companies are mainly on-line open-market consisting of 36% and SNS is up to 80% as the main promotion method. In addition, exports to China account for 71% of all exports. Lastly, 33% of businesses consider viral marketing by influencer and 50% of them make plan to export their items to East Asia. It is of research significance that this study can suggest the successful direction of establishing and operating fashion start-up companies through making good use of Fashion Creative Studio, the supporting program including facility.

• Journal of Science Education
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• v.46 no.1
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• pp.40-52
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• 2022

Daily science classes, which have been continued as part of the spread of participatory science culture, has taken the lead in popularizing science as an effective out-of-school experiential and research activity. However, due to the recent COVID-19 situation, daily science classes have also become an environment in which there is no choice but to switch to non-face-to-face or to combine face-to-face and non-face-to-face education. Therefore, in this study, we examine how elementary school students participating in the non-face-to-face daily science class program change their usual fields of interest, perception of science and technology, interest about science, and scientific competency. In addition, the educational effectiveness of the non-face-to-face daily science class improved by comparing the differences in perceptions of students and parents, and future operation plans were sought. As a result of the study, after participating in the non-face-to-face daily science class program, students' interest in science and technology development, future technology, environmental pollution, and social media increased, and their interest in games decreased. Also, students' interest in science and technology activities, interest in science, and scientific competency also increased. This shows that non-face-to-face daily science class education is effective. Therefore, it was suggested that it is necessary to diversify the learning topics and content levels of the daily science class program, to expand the opportunities of non-face-to-face science education for underprivileged learners, and to develop and share science content using the latest media.

• The Journal of the Korea Contents Association
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• v.22 no.3
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• pp.390-400
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• 2022

University Identity can effectively convey the core values for which schools aim by establishing university identity and integrating one unique image. Therefore, most universities are actively implementing promotional strategies such as newly defining university identity or releasing cultural products. Recently, university brands have been continuously exposed and differentiated through SNS such as Instagram, YouTube, and Facebook as well as existing advertisements and homepages. This study analyzes the identities of the top 80 universities in Korea and China, by referring to the rankings of Asian universities in the 2021 QS World University Rankings, and addresses differences in terms of design shape, number of colors, and use of English. Moreover, 'Cohen's Kappa' consistency analysis was applied to secure data accuracy by analyzing the difference in visual expression of university identity between the two countries through quantification and cross-analysis of visualized university identity design of Korean and Chinese universities. As a result of the study, it is creative, irregular, and has a lot of use of blue, red, and green, and most of them can be seen in less than two colors. In addition, it turns out that word marks and abstract forms of expression are used for university identity design. This study can present implications as effective basic data for internationalizing universities and creating differentiated university identity designs in the future.