• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.11 no.2
• /
• pp.68-81
• /
• 2006

As one of the on-going projects to investigate the biogeochemical characteristics of tidal flat, we develop seasonal mass balance calculations (or DIP, DIN and DON in Gomso Bay. We have obtained 13-hours time-series data of salinity, tidal current, nutrients, and chlorophyll-a of seawater for spring, dry summer, rainy summer and winter during $1999{\sim}2000$. DIP of $-1.10{\times}10^6g\;P\;day^{-1},\;-4.50{\times}10^5g\;P\;day^{-1}$ was out-fluxed from the bay to the bay proper for spring and dry summer, respectively. Whereas $1.06{\times}10^4g\;P\;day^{-1}$ of net influx of DIP was found during winter and $2.72{\times}10^6g\;P\;day^{-1}$ of net influx was also found during the rainy summer. Therefore we suggest the role of Gomso tidal flat as a source of DIP fur the seasons of spring and summer, but as an opposite role during the rainy summer and winter but much smaller in magnitude. Except winter, the advection process by tidal current is found the most dominant flux among the diverse fluxes of DIP in the bay. Whereas ground water is estimated as the strongest flux of TDN except winter. TDN of $1.38{\times}10^7g\;N\;day^{-1},\;2.45{\times}10^6g\;N\;day^{-1},\;and\;4.65{\times}10^7g\;N\;day^{-1}$ was in-fluxed to the bay from the bay proper far spring, rainy summer and summer, respectively. Only $-1.70{\times}10^7g\;N\;day^{-1}$ of net out-flux was found during the winter. Therefore we suggest the role of Gomso tidal flat as a sink of TDN far the year round except winter.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.14 no.1
• /
• pp.1-9
• /
• 2009

Export fluxes of particulate organic carbon were estimated for the first time by using $^{234}Th/^{238}U$ disequilibrium in the southwestern East Sea during August 2007. They were calculated by multiplying POC/$^{234}Th_p$ ratios of sinking particles (larger than 0.7 ${\mu}m$) obtained from 150-200 m water depths to $^{234}Th$ fluxes that were estimated by integrating $^{234}Th/^{238}U$ disequilibrium from surface to 100 m water depth. Export fluxes ranged from 14 to 505 mg C $m^{-2}$ $day^{-1}$, with the highest value at station A2 and the lowest value at station D4. Primary production was well correlated with export flux, indicating that it was a major factor controlling export flux. Export flux in the East Sea was generally higher than those estimated in the open ocean and similar to or somewhat higher than those in the continental marginal seas. Export flux/primary production (EF/PP) ratios varied from 0.29 to 0.62, with an average of 0.43 and were somewhat higher in the basin area than in the coastal area. EF/PP ratio in the East Sea was rather similar to those estimated in the North Sea and Chukchi Sea, but much higher than those in the Labrador Sea, Barents Sea, and Gulf of Lions. Therefore, the East Sea is one of the major areas where a large amount of organic carbon produced in the euphotic zone sinks into the deep layer below 200 m water depth.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.12 no.3
• /
• pp.147-158
• /
• 2007

To clarify the bloom pattern and species succession in phytoplankton community, the population dynamics with the determination of physico-chemical factors have been studies in Masan Bay, the south sea of Korea, for the periods November 2003-October 2004. Concentration of $NH_4-N$ was always higher than that of $NO_3-N$, which was similar level as compared to other costal areas. $PO_4-P$ concentration was lower than those in other coastal areas but similar to oligotrophic environments. Thus, phosphate seems the limiting nutrient rather than nitrogen. $SiO_2-Si$ concentration was also low as compared to other costal areas. Si:P ratio was low from autumn to winter, suggesting silicate and/or phosphate limitation during this period. The cell density of phytoplankton was high in winter 2003 and early autumn 2004. The carbon biomass was high in winter 2003 and summer 2004. And chlorophyll-a concentration was high in late autumn 2003 and summer 2004. Among 78 species of phytoplankton found in the bay during the investigated period, dominant species were two diatoms of Cylindrotheca closterium, Skeletonema costatum, and three dinoflagellates of Heterocapsa triquetra, Prorocentrum minimum, P. triestinum, and one raphidophyte of Heterosigma akashiwo. P. minimum dominated from late autumn to winter, but it was replaced by H. triquetra in late winter. P. triestinum dominated from late spring to early summer. Simultaneously, H. akashiwo cell density steadily increased, and it became dominant with C. closterium in late summer. With decreasing of H. akashiwo and C. closterium, S. costatum became the most dominant species in autumn. The canonical analyses showed that total phytoplankton cell density related to diatom cell density and it was affected by temperature, and concentrations of $NO_3-N\;and\;PO_4-P$. The carbon bio-mass and $chlorophyll-{\alpha}$ concentration related to diatom- and dinoflagellate cell densities and these were affected by flagellate cell density, salinity, and concentrations of $SiO_2-Si\;and\;PO_4-P$. Last six years monitoring data in Masan city obtained from Korean Meteorological Agency indicates gradual increase in air temperature. And the precipitation decreased especially in spring season. The winter bloom found in 2003 may be caused by the increase in the temperature and this bloom subsequently induced the nutrients depletion, which continued until next spring probably due to no precipitation. Therefore, the spring bloom, which had been usually observed in the bay, might disappear in 2004.

• Journal of The Korean Association For Science Education
• /
• v.28 no.5
• /
• pp.495-505
• /
• 2008

The purpose of this study was to analyze the level of evidence used in gifted elementary students' argumentation. The subjects were 15, 5th and 6th grade students selected in the Science Education Institute for Gifted Youth in K University. After the argumentation task was given to students 2 weeks ago, the students grouped themselves in the affirmative and negative and took part in a debate for 2 hours. Their argumentation process was observed, recorded and transcribed for analysis. Transcribed data was given a Protocol Number according to priority and was examined to find out what were the characteristics when students participated in the task. The evidence used in argumentation was graded from level 1 to level 6 according to Perella's Hierarchy of Evidence and the rate of frequency classified by the level was expressed in graph. Students used Level 1- Level 2 evidence above 50% without for or against task. They had weak argumentation making use of low-level evidence such as individual experience, opinion and another person's experience rather than objective evidences. On the other hand, students commented on the lack of opponent's evidence when they could not trust an opponent's evidence. If one team asked the other to present more evidence but could not, they disregarded the question and turned to another topic. And in cases where the opponent team refuted with evidences of high level, the other team just repeated their claim or evaded the rebuttal. The students tended to complete the argument without the same conclusions with some interruptions. The results show that we need an educational programs including scientific argumentation for science-gifted elementary school students.

• Journal of The Korean Association For Science Education
• /
• v.28 no.1
• /
• pp.1-14
• /
• 2008

The image of science is one of the recurrent topics in science education research. In particular, we believe that students' images of Doing-Science-Well could be used for identifying not only students' perceived goals of science learning, but also practical guidelines of effective science teaching. In this study, the students' images of Doing-Science-Well were investigated with the following two research questions: (i) what are student's images of Doing-Science-Well?; (ii) in what contexts do students perceive that someone is doing science well? Thirty seven students in a high school in Seoul, Korea were asked to write their personal experiences by which they realized that someone was doing science well. The main results of the study are the following: Firstly, the images of Doing-Science-Well could be categorized into 'Einstein type', 'Socrates type', 'MacGyver type' and six more types. Secondly, with regard to contexts, students tended to realize that somebody is doing science well in terms of two kinds of contexts: 4 physical contexts and 6 psychological contexts. The findings led us to develop a frame of judging Doing-Science-Well, which combines the types and two kinds of contexts. The frame illustrates the multiplicity of the images of Doing-Science-Well.

• Journal of The Korean Association For Science Education
• /
• v.44 no.3
• /
• pp.249-262
• /
• 2024

The purpose of this study is to analyze the achievement standards of the 2015 revision and 2022 revision of the science curriculum using the TIMSS 2023 science cognitive domain analysis framework. The subject of the study is the achievement standards for all elementary school areas in the 2015 and 2022 revised science curriculum. Three field teachers and one elementary science education expert who majored in elementary science education participated in the research analysis. The results of this study are as follows. First, in the 2022 revised movement and energy field, the ratio of the 'knowing' area was about 16% higher than the 2015 revision, and the ratio of the 'reasoning' area also increased by about 5.8%. Second, in the material field, the proportion of TIMSS 2023 cognitive domains was in the order of 'knowing', 'applying', and 'reasoning' regardless of grade group and curriculum revision period. Third, in the field of life sciences, the proportion of TIMSS 2023 cognitive domains differed depending on grade group and curriculum revision period. Fourth, in the Earth and Space field of the 2022 revision, similar to the other three fields, the proportion of the 'Knowing' field increased and while the 'Applying' field decreased. However, in the 2022 revision, the 'reasoning' area in all three other fields increased, but decreased only in the earth and space fields. Fifth, the 2015 revised integrated unit and the 2022 revised science and society field only covered the elements of 'recognizing' and 'presenting examples' in the 'knowing' area, 'making relationships' and 'explaining' in the 'applying' area and 'Synthesize' in the 'reasoning' area. In the 2022 revised elementary school science field, the proportion of the 'knowing' section was 52.5%, the proportion of the 'applying' section was 33.8%, and the proportion of the 'reasoning' section was 13.7%. In conclusion, in the 2022 revised elementary science achievement standards, the ratio of the 'applying' and 'reasoning' areas was low because the reliance on the 'knowing' area was too high.

• Journal of Service Research and Studies
• /
• v.14 no.2
• /
• pp.1-17
• /
• 2024

One of the most important decisions for managers in the online banner advertising industry, is to choose the best banner alternative for exposure to customers. Since it is difficult to know the click probability of each banner alternative in advance, managers must experiment with multiple alternatives, estimate the click probability of each alternative based on customer clicks, and find the optimal alternative. In this reinforcement learning process, the main decision problem is to find the optimal balance between the level of exploitation strategy that utilizes the accumulated estimated click probability information and exploration strategy that tries new alternatives to find potentially better options. In this study we analyze the impact of word-of-mouth effects and the number of alternatives on the optimal exploration-exploitation strategies. More specifically, we focus on the word-of-mouth effect, where the click-through rate of the banner increases as customers promote the related product to those around them after clicking the exposed banner, and add it to the overall reinforcement learning process. We analyze our problem by employing the Multi-Armed Bandit model, and the analysis results show that the larger the word-of-mouth effect and the fewer the number of banner alternatives, the higher the optimal exploration level of advertising reinforcement learning. We find that as the probability of customers clicking on the banner increases due to the word-of-mouth effect, the value of the previously accumulated estimated click-through rate knowledge decreases, and therefore the value of exploring new alternatives increases. Additionally, when the number of advertising alternatives is small, a larger increase in the optimal exploration level was observed as the magnitude of the word-of-mouth effect increased. This study provides meaningful academic and managerial implications at a time when online word-of-mouth and its impact on society and business is becoming more important.

• Clean Technology
• /
• v.30 no.2
• /
• pp.134-144
• /
• 2024

In this study, the mechanical stability of red mud was improved for its commercial use as a catalyst to effectively decompose HFC-134a, one of the seven major greenhouse gases. Red mud is an industrial waste discharged from aluminum production, but it can be used for the decomposition of HFC-134a. Red mud can be manufactured into a catalyst via the crushing-preparative-compression molding-firing process, and it is possible to improve the catalyst performance and secure mechanical stability through calcination. In order to determine the optimal heat treatment conditions, pellet-shaped compressed red mud samples were calcined at 300, 600, 800 ℃ using a muffle furnace for 5 hours. The mechanical stability was confirmed by the weight loss rate before and after ultra-sonication after the catalyst was immersed in distilled water. The catalyst calcined at 800 ℃ (RM 800) was found to have the best mechanical stability as well as the most catalytic activity. The catalyst performance and durability tests that were performed for 100 hours using the RM 800 catalyst showed thatmore than 99% of 1 mol% HFC-134a was degraded at 650 ℃, and no degradation in catalytic activity was observed. XRD analysis showed tri-calcium aluminate and gehlenite crystalline phases, which enhance mechanical strength and catalytic activity due to the interaction of Ca, Si, and Al after heat treatment at 800 ℃. SEM/EDS analysis of the durability tested catalysts showed no losses in active substances or shape changes due to HFC-134a abasement. Through this research, it is expected that red mud can be commercialized as a catalyst for waste refrigerant treatment due to its high economic feasibility, high decomposition efficiency and mechanical stability.

• Sim-seong Yeon-gu
• /
• v.30 no.1
• /
• pp.31-66
• /
• 2015

A study on a Russian fairy tale entitled "Seven Stars" was conducted from the perspective of analytical psychology. The plot goes as follows. Once upon a time, a village in Russia was suffering from severe drought. Villagers were dying of thirst, and crops were withering day by day. One night, a little girl left their house carrying a wooden dipper to find water for her sick mother by herself. However, water was nowhere to be found. She felt tired and fell asleep. When she woke up, the moon was already over her head, and the dipper had been filled with water. On her way home to give the water to her mother, she found a dog lying on the ground. The dog was also dying of excessive thirst, so she gave the dog a handful of water. Then the wooden dipper suddenly turned into a silver dipper. When she had finally arrived home and her mother has drunk the water, the silver dipper changed into a golden dipper. At that moment, an old man showed up and asked for water. The little girl gave him water. When the old man stared at the water, she realized that there were seven diamonds twinkling like stars in the dipper. The water never ran out. Surprisingly enough, the seven diamonds suddenly soared up into the sky and eventually formed a constellation of the Big Dipper. The water was shared with the other villagers who, then, recovered their strength. The severe drought came to an end, and the villagers danced together with joy. In this fairy tale, the severe drought symbolizes devastation caused by a unidirectional stream of consciousness while the little girl represents a new function, which shows the value of women who can heal and restore from that devastation. Symbolized in a fairy tale character such as 'a daughter' or 'a little girl', the new function eventually reaches up to the value which leads and affects the group as well as individuals. To conclude, this new function represents the unconscious process whose role is to revitalize the maternity and resolve the problems posed to a group as well as individuals.

• Journal of the Daesoon Academy of Sciences
• /
• v.48
• /
• pp.199-237
• /
• 2024

Donghak-gyo, the Teaching of Eastern Learning, is a new religious order founded by Kim Ju-hee, centered around the Donghak (Eastern Learning) lineage. The core thought conveyed in the lyrics of Donghak-gyo songs (gasa) can be identified as the concept of 'Return to the Former World (先天),' considering the frequency of the term and the content of the recited verses. The view of time and destiny (時運觀) held by Eastern Learning emphasizes the concept of 'Another Great Opening.' Donghak-gyo's perspective on time and destiny is further rooted in the concept of 'Return to the Former World.' Donghak-gyo particularly emphasizes the term 'Former World,' and incorporates the Study of Changes (易學) into their songs. They recite verses that depict the situation of the Great Opening as an interaction between yin and yang. In Donghak-gyo, it is emphatically asserted that the completion of the Later World's destiny leads to the achievement of the 'Return to the Former World.' It is sung that with the restoration of destiny associated with the 'Return to the Former World,' the symbolic 'Spring (春)' represented by the virtue of Wood (木德) will return. Donghak-gyo describes the unfolding of a new cycle of destiny (運數) as the 'restoration of Changes (易).' When this occurs, they refer to the emerging new world, characterized by a new order and norms, as the 'Return to the Former World,' asserting that a 'moral world' will be established, leading to the development of a moral civilization. It is also sung that the restoration of the destiny associated with the Return to the Former World is akin to the restoration of the Heavenly Dao (天道). The characteristics of the concept of the Return to the Former World are threefold: firstly, it advocates a nostalgic system; secondly, it is a backward-looking thought; and thirdly, the idea of 'cyclical repetition' encourages tangible actions such as 'returning to the origin' or 'restoring fundamentals.' The concept of Return to the Former World in Donghak-gyo, unlike many new religions of those days, provided a unique conceptualization and understanding of the Former World and presented a new framework for interpretation. It moved away from the notion of discarding the Former World as a relic of an outdated era, and instead interpreted it as a new era to be embraced. Therefore, the concept of 'Return to the Former World' in Donghak-gyo should be re-assessed as one of the ideologies that inherits the pursuit of returning to and restoring the past in Eastern traditions. However, it can be criticized for lacking a concrete methodology with regards to the 'Return to the Former World.' Additionally, it is noted for deficiencies in ethical consciousness and moral virtues. Furthermore, its explanation about the Former World come across as insufficient. Thus, the concept of the 'Return to the Former World' in Donghak-gyo seems to be characterized more by declarative slogans than substantive content.