• Journal of Korean Society of Water and Wastewater
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• v.28 no.5
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• pp.555-560
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• 2014

This study investigates the effect of sodium bicarbonate ($NaHCO_3$) on growth of S.dimorphus. $NaHCO_3$ concentration was varied from 0 to 2 g-C/L. As a result, the increase in concentration of $NaHCO_3$ up to 1.5 g-C/L increased dry weight of algae. The highest specific growth rate of S. dimorphus was $0.36day^{-1}$ which was obtained at concentration of 0.5 g-C/L $NaHCO_3$. pH showed a large variation range at the concentrations lower than 0.5 g-C/L $NaHCO_3$ whereas inorganic carbon, nitrate and phosphorus removal rates were almost same at the concentrations higher than 0.5 g-C/L $NaHCO_3$ (0.75, 1, 1.25, 1.5, 2 g-C/L $NaHCO_3$). Their average inorganic carbon, nitrate and phosphorus removal rate were 70 mg-C/L/d, 11.3 mg-N/L/d, and 1.6 mg-P/L/d, respectively. Thus, $NaHCO_3$ didn't effect on inorganic carbon, nitrate and phosphorus removal rate of S. dimorphus.

• Journal of Korean Society of Water and Wastewater
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• v.28 no.6
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• pp.691-698
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• 2014

This study investigated the effect of a co-culture of Scenedesmus dimorphus and nitrifiers using artificial wastewater on the removal of ammonium, nitrate and phosphate in the advanced treatment. To test the synergistic effect of the co-culture, we compared the co-culture treatment with the cultures using S. dimorphus-only and nitrifiers-only treatment as controls. After 6 days of incubation, nitrate was removed only in the co-culture treatment and total amount of N removal was 1.3 times and 1.6 times higher in the co-culture treatment compared to those in the S. dimorphus- and nitrifiers-only treatments, respectively. In case of total amount of P, co-culture treatment removed 1.2 times and 12 times more P than the S. dimorphus -and nitrifiers-only conditions, respectively. This indicates that the co-culture improved removal rates for ammonium, nitrate, and phosphate. This further implies that there was no need for denitrification of nitrate and luxury uptake of P processes because nitrate and phosphate can be removed from the uptake by S. dimorphus. In addition, co-culture condition maintained high DO above 7 mg/L without artificial aeration, which is enough for nitrification, implying that co-culture has a potential to decrease or remove aeration cost in the wastewater treatment plants.

• Journal of The Korean Association of Information Education
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• v.26 no.1
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• pp.1-10
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• 2022

With the development of artificial intelligence, society is moving toward another world that has never existed before. As a result, interest in artificial intelligence education is also increasing, and research on artificial intelligence education is being conducted more actively in Korea. However, many studies have been conducted focusing on the upper grades of elementary school, and curriculum and programs for the lower grades are still insufficient. Therefore, in this study, a total of 6 sessions of artificial intelligence programs were developed to understand image recognition for the lower grades of elementary school. The validity was secured by conducting expert validity for 8 experts, and the effectiveness was verified through the pre-post-response sample t-test by applying it to the experimental group. As a result, both artificial intelligence understanding and artificial intelligence attitude showed statistically significant results, and both the interest and difficulty of educational programs were found to be suitable for lower grade students. Based on the contents of this study, it is necessary to review its application and effectiveness in various environments through follow-up studies in the future.

• Journal of The Korean Association of Information Education
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• v.26 no.1
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• pp.45-53
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• 2022

The need for artificial intelligence education has emerged, and countries around the world are announcing artificial intelligence strategies. Artificial intelligence education is reflected in the main points of the 2022 revised curriculum general published in Korea. Along with this interest, programs related to artificial intelligence education are being developed, but it is difficult to find artificial intelligence programs for lower grades of elementary school. This study aims to develop a data collection education program for the lower grades of elementary school through a series of analysis-design-development-application-evaluation processes and apply it to first-grade elementary school students to verify its effectiveness. Through the developed program, it is expected that students will be able to understand and feel interested in artificial intelligence, and develop an attitude of collecting data in their daily lives through the process of searching for various types of data in their daily lives.

• 한국정보교육학회:학술대회논문집
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• 2021.08a
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• pp.269-274
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• 2021

With the development of artificial intelligence, society is moving to a different world. As a result, amid growing interest in artificial intelligence education, research on how to teach artificial intelligence is also being conducted more actively in Korea. However, a lot of research is being conducted around the upper grades of elementary school, and curriculum and programs for the lower grades are insufficient. Therefore, this study developed an artificial intelligence program for lower grades. Among them, it was developed focusing on artificial intelligence image recognition. It compares image recognition methods of people, animals, and computers, identifies the characteristics of fallen leaves, and helps them understand the image recognition process of artificial intelligence by classifying them according to the characteristics of fallen leaves. I hope this program will help elementary school students understand the image recognition principle of artificial intelligence in the future.

• 한국정보교육학회:학술대회논문집
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• 2021.08a
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• pp.275-281
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• 2021

Much of our lives are closely related to artificial intelligence, and society is changing more rapidly. Reflecting this era, the need for artificial intelligence education has emerged and various learning methods have been proposed, but guidance on artificial intelligence teaching and learning activities for lower grades elementary school students is insufficient. Therefore, in this study, the data collection education program for the lower grades of elementary school was developed based on the contents standards of the Korea Foundation for the Advancement of Science & Creativity. Focusing on the principles of artificial intelligence and the detailed data area of the utilization area, the focus was on expressing numbers and letters in various ways, such as colors and pictures, and finding various types of data in life to learn the principles of artificial intelligence. Through this program, it is expected that lower-grade elementary school students will be able to understand the importance of data collection in artificial intelligence through the process of knowing about data and collecting sound, picture, and text data.

• 한국해양학회지
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• v.7 no.2
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• pp.74-85
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• 1972

This paper studied the grain size distribution of bottom sediments of Yeongil Bay which is located at the southeastern part of the Korean Peninsula. Sixty four samples collected with snapper and dredger are analyzed by roe Tap Sieve Shaker and Pipette Method. The moment parameters are calculated with the method of Friedman(1961). Most samples are composed of sand size sediments and a few samples are composed of silt and clay. The Yeongil Bay can be divided into gravel-granule zone, sand zone, and silt-clay zone. The sediments near Yeonam- Dong and Hyongsan river are moderately sorted and others are very poorly sorted according to scheme of Friedman91962). In general, sorting values are ranged from 1.0 to 3.5. The samples near Janggigap and Masin-Dong show negative and others show positive skewness values. Skewness values are ranged from -1 to 2. All samples show the leptokurtic distribution except for the samples near Masin- dong and at the deepest place near Janggigap. Kurtosis values are ranged from -1.5 to 21.9. The samples of gravel-granule zone contain more than 50% and those of silt-clay zone contain less than 50% of CaCO$\_$3/. Four different colors, black, yellow, brown and gray, are shown in the sediments of Yeongil Bay.

• Korean journal of applied entomology
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• v.14 no.2 s.23
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• pp.71-76
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• 1975

The study has been carried to find a proper site for seed potato production in Jeon Bug Province, Korea. Two fields, one at the alpine area (700-800 m sea level) in Muju county and the other at the plain area in Jeoniu, were chose for this study. Seed potatoes for the experiment were obtained from Alpine Experiment Station and from the traditional sources in Muju area. During the growing season the virus infection (Potato virus X,S,Y, and M) was detected by serolgical method. The average percent of virus infection on the original seed potatoes, which have been used as a seed source in Korea, was $50.5\%$, and the ratio of the infection for each of potato virus, Y, M and X was 34..87, 40.33, 41.00 and $87.10\%$, respectively. Infection percentage of virus at first year in Muju area was $11.7\%$ and those in Jeonju area was $18.95\%$. In case of potato virus Y, the most prevalent virus in Korea, lower Infection percentage $(6.45\%)$ was found in Muju area than in tile Jeonju area $(26.0\%)$ when the seed from Alpine Experiment Station was planted in both areas. The percentage of infected seed potato, Alpine Experiment Station$(41.75\%)$ was almost the same as those from the traditional sources in Muju $(42.17\%)$. The production of seed potato, however, was much better by the seeds from Alpine Experiment Station.

• Journal of Korean Society of Forest Science
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• v.98 no.1
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• pp.1-7
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• 2009

We investigated the genetic variation and structure in Korean Arborvitae (Thuja koraiensis Nak.), by 29 examining I-SSR polymorphic loci in 84 individuals distributed among four natural populations in Korea. The level of population genetic diversity ($A_e$=1.44, P=72.42, $H_e$=0.258, S.I.=0.385) was similar to or slightly higher than that of plants with similar ecological traits and life history (Cupressaceae). Most genetic diversity was allocated among individuals within populations (${\Phi}_{ST}$=0.13). The UPGMA dendrogram based on genetic distance failed in showing decisive geographic relationship. The Mt. Bangtae population had the lowest level of genetic diversity and was the most distinctive from the other populations. Mt. Jang population which is possessed of the highest level of genetic variation and Mt. Bangtae population which is consisted of heterogeneous was considered to be a prime candidate for the conservation studies.

• Journal of Korean Society of Forest Science
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• v.108 no.1
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• pp.10-20
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• 2019

The purpose of this study is to identify the long-term area changes in the subalpine coniferous forests in Korea in order to understand the changes in the subalpine forest ecosystems vulnerable to climate change. We analyzed 20 years of time-series Landsat satellite images (mid 1990s, mid 2010s) for change detection of coniferous forests and compared with the long term changes of climate information to identify their relationship in the study area. As a result, the area of coniferous forests in the study region decreased by 25% over 20 years. The regions with largest changes are Seoraksan, Baegunsan-Hambaeksan-Jangsan, Jirisan, and Hallasan. The region with the largest decrease in area was Baegunsan (reduced area: 542 ha), and the region with large decrease in area and the largest rate of decrease was Hallasan (rate of decrease: 33.3%). As the Jeju region has the most rapid temperature rise, it is projected that Hallasan is the most vulnerable forest ecosystem affected by climate change. The result of this study shows that from a long-term perspective the overall coniferous forests in the subalpine region are declining, but the trend varies in each region. This national and long-term information on the change of coniferous forests in the subalpine region can be utilized as baseline data for the detailed survey of endangered subalpine coniferous trees in the future.