• Journal of the Korea Institute of Information Security & Cryptology
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• v.32 no.2
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• pp.255-266
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• 2022

Messenger applications applied end-to-end encryption on their own to prevent message exposure to servers. Standardization of a group messaging protocol called Message Layer Security (MLS) with end-to-end encryption is being discussed for secure and efficient message communication. This paper performs safety checks based on the operation process and security requirements of MLS. Confidentiality to a middleman server, which is an essential security requirement in messenger communication, can be easily violated by a server administrator. We define a server administrator who is curious about the group's communication content as a curious admin and present an attack in which the admin obtains a group key from MLS. Reminds messenger application users that the server can view your communication content at any time. We discuss ways to authenticate between users without going through the server to prevent curious admin attacks.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2012.05a
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• pp.123-123
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• 2012

• Restorative Dentistry and Endodontics
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• v.26 no.4
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• pp.341-349
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• 2001

Dental caries is the most common oral disease. There are many factors contributing to its development, but complete understanding and prevention are not fully known. However, it is possible to remineralize the early enamel curious lesion by fluoride containing remineralization solution. Recently the pH-cycling model has been used to examine the effect of fluoride solution on remineralization of artificial caries in vitro as it can closely simulate the conditions encountered in vivo within a carefully controlled environment. The aim of this study was to evaluate the remineralizing effects of supersaturated buffer solutions under pH-cycling model. The specimen with 3mm-diameter was made using mature bovine incisors which has no caries and has sound enamel surface. Early curious lesions were produced by suspending each specimens into demineralization solution at pH 5.0 for 33 hours and the specimen whose surface hardness value ranged from 25 to 45 VHN were used. The pH cycling treatment regimen consisted of 5 min soaks of three treatment solutions four times per days for 15 days and the continuous cycling of demineralization and remineralization were carried out for 15 days. Following the pH-cycling treatment regimen, the specimens' surface microhardness were measured by the Vickers hardness test (VHN) and analyzed by ANOVA and Duncan's multiple-range test. 1. The surface microhardness value of supersaturated solution, Senstime, and Gagline groups were increased after pH cycling, and that of supersaturated solution was significantly Increased compared to saline group(P<0.05). 2. The surface remineralization effect of fluoride containing solutions was accelerated by saliva under pH-cycling mode 3. The pH cycling model was considered appropriate to mimic the intra-oral pH changes when evaluating demineralization and remineralization in vitro. Under the results of above study, salivary remineralization effect can be improved by fluoride containing remineralization solution. The pH-cycling model was considered appropriate to mimic the intra-oral pH changes when evaluating demineralization and remineralization in vitro.

• Fashion & Textile Research Journal
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• v.15 no.5
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• pp.815-824
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• 2013

This study divides female consumers according to eco-friendly attitudes and the purchase frequency of eco-clothing products; in addition, it analyzes the characteristics of each group in terms of LOHAS lifestyles, the attitudes for eco-clothing products, and satisfaction. Eco-clothing attitudes of female consumers were lower than eco-friendly attitudes. A total of 360 female consumers were divided into 4 group according to purchase frequency and the eco attitude, Type 1: survival (33.0%), Type 2: wellbeing (25.6%), Type 3: curious (15.0%), Type 4: LOHAS (26.4%); in addition, age, income, marit alstatus, occupation, LOHAS lifestyle and shopping places were differentiated by type. Type 1 (low eco attitude and low eco-clothing purchase) were composed of the youngest, college students, low income, low level of LOHAS lifestyles and low level of eco-clothing attitude. Type 2 (high eco attitude and low eco-clothing purchase) were interested in healthy eating & exercise among LOHAS lifestyles; in addition, Type 1 & 2 showed alow level of eco-clothing satisfaction. Type 3, low eco attitude and high eco-clothing purchase, were characterized with high expenditures on clothing relative to income as well as lower levels of family activities and leisure life than LOHAS Type 4. Type 4 (high eco attitude and high eco-clothing purchase) were the oldest group and mostly composed of married workers (the highest income) with the highest LOHAS lifestyles and the highest level of eco-clothing satisfaction.

• Publications of The Korean Astronomical Society
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• v.30 no.2
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• pp.267-268
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• 2015

One of the long-standing problems in modern astronomy is the curious division of globular clusters (GCs) into two groups, according to the mean period (<$P_{ab}$>) of type ab RR Lyrae variables. In light of the recent discovery of multiple populations in GCs, we suggest a new model explaining the origin of the Sandage period-shift and the difference in mean period of type ab RR Lyrae variables between the two Oosterhoff groups. In our models, the instability strip in the metal-poor group II clusters, such as M15, is populated by second generation stars (G2) with enhanced helium and CNO abundances, while the RR Lyraes in the relatively metal-rich group I clusters like M3 are mostly produced by first generation stars (G1) without these enhancements. This population shift within the instability strip with metallicity can create the observed period-shift between the two groups, since both helium and CNO abundances play a role in increasing the period of RR Lyrae variables. The presence of more metal-rich clusters having Oosterhoff-intermediate characteristics, such as NGC 1851, as well as of most metal-rich clusters having RR Lyraes with the longest periods (group III) can also be reproduced, as more helium-rich third and later generations of stars (G3) penetrate into the instability strip with further increase in metallicity. Therefore, although there are systems where the suggested population shift cannot be a viable explanation, for the most general cases, our models predict that RR Lyraes are produced mostly by G1, G2, and G3, respectively, for the Oosterhoff groups I, II, and III.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.5
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• pp.1653-1670
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• 2022

The fear that location privacy may be compromised greatly hinders the development of location-based service. Accordingly, some schemes based on the distributed architecture in peer-to-peer network for location privacy protection are proposed. Most of them assume that mobile terminals are mutually trusted, but this does not conform to realistic scenes, and they cannot make requirements for the level of location privacy protection. Therefore, this paper proposes a scheme for location attribute-based security authentication and private sharing data group, so that they trust each other in peer-to-peer network and the trusted but curious mobile terminal cannot access the initiator's query request. A new identifier is designed to allow mobile terminals to customize the protection strength. In addition, the caching mechanism is introduced considering the cache capacity, and a cache replacement policy based on deep reinforcement learning is proposed to reduce communications with location-based service server for achieving location privacy protection. Experiments show the effectiveness and efficiency of the proposed scheme.

• Journal of The Korean Association For Science Education
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• v.35 no.1
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• pp.27-35
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• 2015

General education is changed by accepting the change in education environment to digital generation, emphasis about student-centered education, and change of teacher's role. E-learning has taken center stage as an effective learning environment but the problems are drawn for the absence of interaction that is important in learning. In this study, on the basis of questionnaire results about learning using website, we operated blended-learning where students come and go in cyberspace and physical space to set up the lesson environment for emphasizing interaction. We selected a control group (N=40) and an experimental group (N=40) from second grade students in a middle school for this research. General instructor-led lessons were implemented in the control group and blended-learning lessons to emphasize interaction between teacher and students were implemented in the experimental group. The experiments were applied to eight class-hours in 'characteristics of matter' unit. We implemented Test of Science Related Attitude (TOSRA) to the students before and after the lessons and administered questionnaire for checking attitude changes and perception in students. The results of the test show that the experimental group students were more encouraged and became more confident and curious about scientific learning than the control group students. The analysis of the interview and results of TOSRA show that blended-learning provided guidance and feedback by the teacher to the experimental group students more than the control group students. Blended-learning is suggested as a learning-method that is helpful in improving scientific attitude in students because it enables them to express their experiences without limit of time-space and promote interaction between teacher and students.

• The Journal of the Korea Contents Association
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• v.12 no.11
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• pp.388-397
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• 2012

The tennis was one of the most popular sport in the general physical education lesson. However there are many problems such as difficult of improvement tennis skill, lack of class days and so many students in a class. These reasons could ultimately damage the overall quality of class. The purpose of this research was to beginner students was fun and easy to learn. The tennis lesson using tools were 1.selective hitting ball, 2. high net hitting ball, 3. hitting orange ball. Scores of the experimental group(n=23) and the control group(n=21) were compared. In order to verify course content was the same 15 weeks, conducted a tennis teaching methods to take advantage of the tools. And tools to take advantage of the students who participated in a class analysis of the qualitative data (interviews, documents, questionnaires, observations, journals). As a result, the satisfaction scores of the experimental group were higher than those of the control group. The tennis lesson using tools to take positive effect(meaning, improved skill, easy, fun/curious/confident) and negative effect(difficulties of adaptation, a high challenge level) was induced. In summary of the quantitative/qualitative data 'Orange Ball' has a positive impact on the girls than boys and teaching methods using tools gave generally positive influence to students.

• Journal of Korean Home Economics Education Association
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• v.35 no.1
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• pp.53-72
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• 2023

This study aimed to develop educational material on the proper use of plant-based milk alternatives in the form of a card news, based on a focus group interview(FGI) with adult consumers. The FGI participants were individuals who had directly purchased cow's milk, soy milk, or other plant-based milk alternatives within the past three months and consumed them at least once a month. The study consisted of 17 adults between the ages of 19 and 63 years who met these criteria(9 males and 8 females). It was identified what participants were curious about, interested in, and needed information regarding the proper use of plant-based milk alternatives through FGI. A 10-page card news was developed that was highly usable, taking into account the FGI results and the latest literature. In conclusion, this study developed a card news aimed at promoting the proper use of plant-based milk alternatives, which can be easily disseminated online in line with the trends in food consumption and digitization. The results of this study suggest that the continuous development and distribution of educational materials that reflect food consumption trends and maximize their usability should be provided for dietary life education, such as school subjects or out-of-school programs.

• Journal of East-West Nursing Research
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• v.5 no.1
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• pp.19-35
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• 2000

This study confirms and describes the meaning of the true experience on sexual perception of female college students as it is. Thus this study, revealing the structure of the meaning, tried to use phenomenal study tool as qualitative research design in order to seek nursing intervention for them. The method of data collection of this study was achieved February, 2000$\sim$August, 2000 through systematic interview, participation and observation from a focus group. The number of each focus group was 3 to 4, and the study analyzed with Giorgi method after selecting total 3 groups with 10 to saturate data, considering of the closeness among group members. The results are as follow; 1) Feeling psychological uneasy : feeling special mood, mysterious thing, tense thing, curious thing, concealing thing 2) Being to someone : receiving unilaterally, giving ahead, attracting attention, being to, being selected unilaterally 3) Feeling like to do together : relying, contacting, being together 4) Accepting another one's self : understanding the partner, taking responsibility for each other, enduring, trusting each other 5) Trying to be best to the partner : physically being pure, mentally being pure, being only one person to the partner, being open to each other, feeling free 6) Harmonizing conditions with conditions : considering appearance, one's family, economic support and so on 7) Making a love without premise of marriage : making a difference between marriage and love 8) Being a difference between men and women : being a different position, being shameful (because of not having a boyfriend), indecent thing 9) Being for a new life : conceiving a new life 10) Being able to have body touch : being able to kiss, being able to sleep together, being able to touch body 11) Being able to make homosexual love : being able to do homosexual love From the above results, right sexual education should deliver the value of sex which exists for life. So we need to develop the Korean-typed sexual education, according to the social and cultural background and reasonable demand level of education subjects. Furthermore we should give systematically connected education through the development of sexual education program by a developmental stage on the sex with broad and dynamic features, revealing different shapes each period of life. Since the members' value by culture is very different, reasonable and healthy sexual education cannot be done through a education program from foreign cultures. Consequently, the development of the study and program on sexual perception of Korean female college students suitable for the Korean cultural situation will be done.