• Journal of the Korean Applied Science and Technology
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• v.40 no.6
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• pp.1547-1556
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• 2023

This study was conducted to check the anti-bacterial ability against Malassezia furfur by mixing Szygium aromaticum and Coptis japonica extracts and to evaluate the antioxidant and anti-inflammatory ability by creating an optimal mixture. Szygium aromaticum and Coptis japonica were extracted with 70% ethanol, 100% methanol, and water to evaluate the antibacterial ability, and it was confirmed that 100% methanol extract of Szygium aromaticum and Coptis japonica water extract had the highest anti-bacterial ability. In addition, when the two extracts were mixed and the anti-bacterial ability was evaluated by ratio, the ratio of 9:1 showed the best activity, and it was confirmed that the antioxidant activity of the mixture was excellent. In Raw 264.7 cells, LPS was used to induce inflammatory responses and confirmed anti-inflammatory activity at 1, 10, 50, and 100 ㎍/mL that did not affect survival, and it was confirmed that NO-production inhibition and IL-6 expression inhibition and COX2 and iNOS protein expression inhibition activity were excellent at 10, 50, and 100 ㎍/mL. Through this study, it is thought that the mixture of Szygium aromaticum100% methanol extract and Coptis japonica water extract can be used as a natural ingredient in functional cosmetics because of its excellent antibacterial and anti-inflammatory effects.

• Journal of the Korean Applied Science and Technology
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• v.40 no.6
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• pp.1567-1579
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• 2023

Sucralose is used as a sucrose alternative in the food sector and is a globally approved pyrogenic, high-intensity artificial sweetener. However, due to the lack of studies on the effects of sweeteners on the brain, this study confirmed whether short-term consumption of sucralose has cognitive and memory protective effects in scopolamine-induced memory-injured animal models. After oral administration of sucralose 2, 5, and 10 mg/kg, scopolamine (1 mg/kg) was administered to the control group and the drug group 30 minutes later, and saline was administered intraperitoneally to the normal group, followed by behavioral experiments As a result of the experiment, Y-Maze, passive avoidance, and Morris WaterMaze recovered more than 10% of cognitive function compared to the control group. In addition, as a result of measuring proinflammatory cytokines, sucralose was found to inhibit IL-6 and TNF-α by more than 30%, and we observed that the expression level of ERK-CREB with intracellular signaling mechanisms increased in a concentration-dependent manner. Therefore, it suggests that sucralose is associated with functional foods for the prevention of functional food patients.

• Journal of Advanced Navigation Technology
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• v.27 no.6
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• pp.716-723
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• 2023

Global discussions are actively underway regarding the introduction of urban air mobility (UAM) to revolutionize the paradigm in the innovative mobility industry. While research related to airspace, vertiports, navigation, and communication pertinent to Korean UAM is actively pursued by relevant research institutions, there is a significant dearth in studies focusing on establishing concepts for operational management by UAM operators and formulating control procedures. The commercialization of UAM necessitates the establishment of standardized operational management concepts, pivotal as benchmarks for the individual system development among multiple UAM operators. This paper analyzes UAM exceptional law, operational readiness, existing regulations pertaining to commercial and rotary-wing aircraft, and proposes suitable approaches to formulate domestic low-density operational management and control procedures. By presenting strategies for conceptualizing operational management and control procedures in the initial low-density environment for UAM, this paper aspires to contribute to future trail operations and the wider adoption of UAM.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.27 no.1
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• pp.31-44
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• 2024

The coastal dune ecosystem is one of the ecosystems under the most development pressure in Korea. Therefore, it is necessary to study the ecological location and related ecological phenomena of coastal dune plants, but related studies are lacking. Through this study, we intend to conduct research on the structure and restoration of dune plants, focusing on the coastal dunes in Jeju Island, which are affected by artificial development pressure and the continuous increase in tourists among many coastal dunes in Korea. Ecosystems of coastal sand dunes for vegetation survey in Jeju Island are selected based on naturalness and preservation. In this study, 23 major coastal dunes on Jeju Island including Udo were selected. In the coastal dunes of Jeju Island, a whole species survey and quadrat survey were carried out. The vegetation survey at study sites were conducted on May to September 2022, when the vegetation is clearly visible. At the survey site, the dune area was identified at the beginning and the plant species were recorded until no more new species appeared. Vegetation survey in the field was performed by 103 quadrat establishments and was conducted using Braun-Blanquet method. A total of 277 species appeared, and the most common species were Vitex rotundifolia and Calystegia soldanella. The frequency of both Vitex rotundifolia and Calystegia soldanella was approximately over 90%. The proportion of woody and herbaceous in all emerging species was 7.2% and 92.8%, respectively. The total number of species found in the quadrat survey was 98. As a result of classifying plant communities based on species dominance in the quadrats, it was analyzed into 30 plant communities. The plant communities that appeared with a frequency of 2 or more on the main island of Jeju were Vitex rotundifolia, Imperata cylindrica var. koenigii, Ischaemum antephoroides, Wedelia prostrata, Elymus mollis, Calystegia soldanella, Artemisia scoparia, and Tetragonia tetragonoides. The DCCA(detrended canonical correspondence analysis) based on the vegetation and environment factor matrix showed that the height and covers of the dominant plant species explain significantly the variation and distribution of coastal sand dune species on Jeju island. Thus, we may propose a plan to restore the coastal dunes of Jeju island as helping colonization and establishment of mainly sand dune native perennials and trees, preserving native plant communities that are declining and preserving present tree strips of Pinus thunbergii, Litsea japonica, Pittosporum tobira and Vitex rotundifolia.

• Education of Primary School Mathematics
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• v.27 no.1
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• pp.91-110
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• 2024

The purpose of this study is to explore visual models for deriving the fractional division algorithm, to see how students understand this integrated model, the rectangular partition model, when taught in elementary school classrooms, and how they structure relationships between fractional division situations. The conclusions obtained through this study are as follows. First, in order to remind the reason for multiplying the reciprocal of the divisor or the meaning of the reciprocal, it is necessary to explain the calculation process by interpreting the fraction division formula as the context of a measurement division or the context of the determination of a unit rate. Second, the rectangular partition model can complement the detour or inappropriate parts that appear in the existing model when interpreting the fraction division formula as the context of a measurement division, and can be said to be an appropriate model for deriving the standard algorithm from the problem of the context of the inverse of a Cartesian product. Third, in the context the inverse of a Cartesian product, the rectangular partition model can naturally reveal the calculation process in the context of a measurement division and the context of the determination of a unit rate, and can show why one division formula can have two interpretations, so it can be used as an integrated model.

• Journal of The Korean Association For Science Education
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• v.26 no.1
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• pp.25-39
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• 2006

Most student misconceptions about evolution are similar to misconceptions and disputes which early scientists had in science history. The aim of this study was to analyze student evolution conceptions based on science history, there by revealing for effectively teaching strategies on evolution. A test was developed according to Lee's three dimensional framework (2004) on evolution concept changes. Lee's framework had been constructed according to 4 stages of evolution concept changes in history in three-dimensional aspects such as mechanism, time, and subject: before Lamarck (stage 1), Lamarck (stage 2), Darwin (stage 3), and after Darwin (stage 4). Major results were as follows. First, the evolution conceptions of students appeared fixed to stage 2 regardless of grade. Moreover, students usually possessed Lamarckian thought and did not show consistency in evolution concepts among the three dimensional aspects of mechanism, time, and subject. Therefore, students were found to apply different conceptions of evolution to each different situation.

• Journal of The Korean Association For Science Education
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• v.26 no.3
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• pp.376-384
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• 2006

The purposes of this study were to analyze the frequency and type of volition strategy, according to achievement level, employed by students with high learning motivation, and to identify the role volition strategy plays in keeping students motived to learn science. To accomplish these aims, two groups of students(each containing three members) were selected. Students in the two groups both had the same cognitive level and high learning motivation. However, one group's science achievement was high, and the other was low. Through interviews and class observations, volition strategies students in the two groups used when they encountered hindrances in science learning were compared. Results of the study revealed a relationship between achievement level and volition strategy. Students showed differences in the frequency and types of volition strategies used according to science achievement. It was found that students with higher achievement levels used volition strategies more often to overcome hindrances in science learning than those with lower achievement levels. Furthermore, students with higher achievement levels generally used internal mind control strategies while those with lower achievement levels used environmental control strategies. Lastly, findings found that the types of volition strategies used by lower achievement level students were very limited.

• Journal of The Korean Association For Science Education
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• v.26 no.2
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• pp.239-245
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• 2006

The purposes of this study were to develop and implement a teaching strategy that reinforced teacher-student interaction for middle school first grade science and investigate the impact of the teaching strategy on student comprehension of scientific concepts, logical thinking ability, and science-related attitudes. 200 students attending a co-ed middle school located in Gyeonggi province were selected for the study and divided into an experiment and control group each consisting of 100 pupils. The teaching strategy reinforcing teacher-student interaction was applied to the experiment group, while conventional teaching, teacher-led lecturing, was carried out on the control group. To accomplish reinforced teacher-student interaction teacher asked students diversified questions and gave delayed feedbacks that deliberately focused on thought provocation. Results showed that the developed teaching strategy was effective in improving the students' logical thinking ability(p<.01). However, no significant differences were found in student comprehension of scientific concepts and science-related attitudes between the experimental and control group(p<.05). It was determined that more sound research is needed to develop and apply a lesson plan based on the teaching strategy used in this study.

• Journal of The Korean Association For Science Education
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• v.27 no.1
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• pp.50-58
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• 2007

In this study, students' thoughts were searched according to the types of experiments related to the "law of definite proportions" in 9th grade science textbooks. The most common four types of experiments in textbooks were selected and analyzed for this study. It was found that the experiments needed various preconceptions and complex inferring process by students. But most of the students could not catch the concept understanding desired from the experiments. They just perceived simple observation from their senses. These phenomena were common regardless of types of experiments. These means that the level of preconceptions and inferring process for the interpretation of the experimental data did not match with students' level of thoughts. The goals of the experiments in science textbooks are to increase students' inquiry ability, and to acquire science concepts by themselves from the experiment results. But if the contents of experiments are not suitable to students' understanding level, the educational effects of the performance of these experiments were not positive. Therefore, these experiments need contents revisions for students to acquire the concept related to the "law of definite proportions" by themselves.

• Journal of The Korean Association For Science Education
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• v.27 no.9
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• pp.854-869
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• 2007

In this study, we investigated secondary science teachers' internalization of constructivistic science teaching who participated in a collaborative program between teachers and researchers designed by researchers according to constructivist views. The program consisted of lecture, workshop, and small group activities. New trends in science education and framework for science teaching were introduced during lectures, and understanding about the framework were deepened by analyzing school science classes recorded during workshops. In small group activities, participating teachers and researchers cooperated to design science lesson plans using science teaching frameworks. Five secondary science teachers participated in collaborative workshops. Collaborative programs were video-taped. Semi-structured interviews were conducted before and after workshops. All data recorded were transcribed and analyzed. In the process of internalization, participating teachers attended on different parts. Various and discernable factors such as there own background, beliefs, values, and school context produced tensions with or facilitated internalization of constructivistic science teaching. Teaching experiences and student understanding affected teachers' lesson planning activities. Teachers also showed different understandings on inquiry, application, and model from the framework, and they interpret those concepts in the framework based on their prior understanding. They perceived that too much content should be dealt within relatively limited time. Therefore, they tended to separate science class into two parts when developing science lessons: explaining science content by lecture and science laboratory as a constructivistic activity. The results of the study provide meaningful implications to the constructivist teacher education and professional development.