• Title/Summary/Keyword: materials science

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Effects of Planting Date and Mulching Material on Yield of Rehmannia glutinosa LIBOSC HIZ (지황(地黃)의 파종기(播種期) 및 피복재료(被覆材料)가 수양(收量)에 미치는 영향(影響))

  • Choi, In-Sik;Kim, Jun-Ho;Cho, Jin-Tae;Hong, Yoo-Ki;Song, In-Kyu;Park, Sung-Kyu;Son, Seok-Yong
    • Korean Journal of Medicinal Crop Science
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    • v.2 no.2
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    • pp.127-132
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    • 1994
  • This experiment was carried out to clarify the effects of planting date and mulching material on the yield characters and tuber yields of Rehmannia glutionsa LIBOSC HIZ on experimental fields of Chungbuk Provincial Rural Development Administration from 1985 to 1987. Emergence period had no difference among planting dates, but it was late about 10 days in rice straw mulching compared with that of others. Leaf length and width showed no differences among planting dates and mulching materials, and no. of fresh leaves was decreased in the order of April 25, May 10 and April 10 with planting dates. Sugar content of tuber was highest on May 10 planting and in open fields. Tuber yield increased 8% on April 25 planting and it decreased 2% on May 10 planting compared with April 10 planting. The white P. E. mulching and rice straw mulching brought yield increase as 22% and 17%, respectively, compared with that from the open field.

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An Exploratory Study on Fashion Retail Borrowing in Korea (대우한국시상령수차대적연구(对于韩国时尚零售借贷的研究))

  • Lee, Mi-Young;Kim, K.P. Johnson
    • Journal of Global Scholars of Marketing Science
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    • v.20 no.1
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    • pp.70-79
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    • 2010
  • There has been some research conducted that addressed immoral consumer behaviors in Korea; however, most of this research focused on purchasing counterfeits or shoplifting. High return rates of apparel and used apparel returns have been acknowledged as problem areas within the fashion industry. However, very few researchers have addressed this issue. Therefore, the goal of this research was to explore consumer's retail borrowing experience using a mixed methods approach. In study 1 Korean consumer's retail borrowing experiences was explored through focus group interviews. Findings informed study 2 an examination of apparel consumers' attitudes toward retail borrowing behavior via an online survey. Findings assist both researchers' and practitioners' understanding of retail borrowing behaviors and provide insight into retail borrowing issues in the apparel retail industry. For study 1, five focus-group interviews were conducted with seven panels of individuals that had retail borrowing experience within the past year. Thirty-five Korean consumers who lived in a metropolitan area participated in the focus group interviews. Most of consumers were in their 20's (n=21) and were women (n=24). Most participants purchased apparel items from a retail store and returned the worn items for either a full refund or exchanged the worn item for another item. Motives underlying retail borrowing behavior included social needs, job-related needs, fashion needs, and "smart shopping." Similar to existing research findings from other countries, social needs were the most frequently mentioned cause of retail borrowing in fashion stores. Consumers' moral values, attitude toward large corporations, and prior retail borrowing experience were mentioned as possible factors affecting consumers' retail borrowing behavior. For study 2, the questionnaire used to gather the data was developed based on the findings of part I and existing research. Questions concerning consumers' moral beliefs, sensation seeking tendencies, self-worth, past retail job experience, retail borrowing experience, and some demographic characteristics were included in the questionnaire. The data were collected via an online survey using an online panel provided by a commercial online research company located in Seoul, Korea. In order to obtain various consumers, a quota sample was (male: female=1:1, 20's:30's:40's=1:1:1, retail experience: no retail experience=1:3) obtained from the company. A total of 401 consumers who had shopped for apparel items during the prior 6 months participated in the online survey. The results indicated that 19.7% of the respondents reported they had experience borrowing fashion merchandise. Among these individuals, male borrowers (57%) outnumbered female borrowers. In terms of age distribution, x2 revealed that there was a statistical difference between respondents with and without retail borrowing experiences: 41.8% of the respondents with retail borrowing experience were in their 40's, while respondents without retail borrowing experience were evenly distributed between their 20's to 40's. There was also a significant difference between respondents with and without retail borrowing experience in terms of income: respondents with retail borrowing experience tended to have higher incomes than those without retail borrowing experience. T-tests were performed to compare respondents' fashion shopping behavior, moral beliefs, sensation-seeking tendencies, and attitudes toward retail borrowing behavior between participants with and without retail borrowing experience. As compared to those with no borrowing experience, respondents with experience tended to shop for fashion items more frequently and spent more on shopping for fashion items. Consumers with experience borrowing tended to have higher sensation-seeking tendencies than consumers without retail borrowing experience. A regression analysis revealed that attitudes toward fashion retail borrowing were negatively related to consumers' moral beliefs, but positively related to monthly fashion shopping frequency, sensation-seeking tendencies, and past fashion retail borrowing experience. Among these variables, past retail borrowing experience was the most significant predictor, followed by moral beliefs. This research serves as an initial attempt to address the motives that underlie retail borrowing behaviors and the factors affecting those behaviors. The findings of this study may facilitate an understanding of the consumer's retail borrowing, which will provide a basis for approaches that may help decrease retail borrowing and inappropriate returns at fashion retail stores. The findings may also provide materials for consumer education over the long term. In order to better understand fashion retail borrowing behavior, more research is needed in the future.

Electrospun Silk Nano-Fiber Combined with Nano-Hydoxyapatite Graft for the Rabbit Calvarial Model (토끼 두개골 결손부에서 전기 방사된 나노실크-수산화인회석 복합체를 이용한 골재생 효과에 대한 연구)

  • Kye, Jun-Young;Kim, Seong-Gon;Kim, Min-Keun;Kwon, Kwang-Jun;Park, Young-Wook;Kim, Jwa-Young;Lee, Min-Jung;Park, Young-Hwan
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.32 no.4
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    • pp.293-298
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    • 2010
  • Purpose: The objective of the present study was to determine the capability of electrospun silk fibroin as a biomaterial template for bone formation when mixed with nano-hydoxyapatite in vivo. Materials and Methods: Ten New Zealand white rabbits were used for this study and bilateral round shaped defects were formed in the parietal bone (diameter: 8.0 mm). The electrospun silk fibroin was coated by nano-hydroxyapatite and grafted into the right parietal bone (experimental group). The left side (control group) did not receive a graft. The animals were sacrificed at 6 weeks and 12 weeks, humanly. The microcomputerized tomogram (${\mu}CT$) was taken for each specimen. Subsequently, they were undergone decalcification and stained for the histological analysis. Results: The average value of all measured variables was higher in the experimental group than in the control at 6 weeks after the operation. BMC in the experimental group at 6 weeks after operation was $48.94{\pm}19.25$ and that in the control was $26.17{\pm}16.40$ (P = 0.027). BMD in the experimental group at 6 weeks after operation was $324.59{\pm}165.24$ and that in the control was $173.03{\pm}120.30$ (P = 0.044). TMC in the experimental group at 6 weeks after operation was $19.50{\pm}6.00$ and that in the control was $10.52{\pm}6.20$ (P = 0.011). TMD in the experimental group at 6 weeks after operation was $508.88{\pm}297.57$ and that in the control was $273.54{\pm}175.91$ (P = 0.06). Gross image of both groups showed higher calcification area at 12 weeks than them in 6 weeks. The average value of ${\mu}CT$ analysis was higher at 12 weeks than that in 6 weeks in both groups. BMC in the experimental group at 12 weeks after operation was $51.21{\pm}8.81$ and that in the control was $33.47{\pm}11.13$ (P = 0.010). BMD in the experimental group at 12 weeks after operation was $323.39{\pm}21.54$ and that in the control was $197.75{\pm}76.23$ (P = 0.012). TMC in the experimental group at 12 weeks after operation was $21.44{\pm}5.30$ and that in the control was $13.31{\pm}4.17$ (P = 0.008). TMD in the experimental group at 12 weeks after operation was $524.47{\pm}19.37$ and that in the control was $299.60{\pm}136.20$ (P = 0.016). Conclusion: The rabbit calvarial defect could be successfully repaired by electrospun silk nano-fiber combined with nano-hydroxyapatite.

Correlation between Steroid Hormone Metabolites and Leiomyomas of Uterus (자궁근종과 성호르몬 대사물과의 연관성)

  • Bai, Sang-Wook;Jung, Byung-Hwa;Chung, Bong-Chul;Jeon, Jin-Dong;Lee, Hyun-Jung;Kwon, Han-Sung;Chung, Kyung-Ah;Kim, Sei-Kwang;Park, Ki-Hyun
    • Clinical and Experimental Reproductive Medicine
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    • v.28 no.4
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    • pp.279-286
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    • 2001
  • Objective: To elucidate 1) whether there are any differences in the urine concentrations of steroid hormone metabolites between patients with leiomyoma and normal controls 2) the correlation between urinary profiles of steroid hormones and leiomyomas of the uterus according to their type, location, volume, and weight. Materials of Methods : The study population consisted of 37 premenopausal patients with uterine leiomyoma and the control group consisted of 25 premenopausal normal volunteer women without uterine leiomyoma. Confirmation of the existence of uterine leiomyoma was done by ultrasonography and histopathological examination after surgery. The volume of the leiomyoma was estimated by trans-abdominal and/or trans-vaginal ultrasonography. The Leiomyomas were divided into 3 types (subserosal, intramural and submucosal). Seventeen patients had subserosal type of leiomyoma, 10 with the intramural type and 10 with the submucosal type. The locations of the leiomyoma were also divided into 3 groups (fundus, body and isthmus). Seventeen patients showed a fundus location, 10 in body, and 10 in isthmus. We compared urinary profiles of the endogenous steroids between patients with leiomyomas and normal controls, and also investigated the relationship between urinary profiles of the endogenous steroids and leiomyomas according to their type, location, volume and weight by using highly sensitive Gas Chromatography-Mass Spectrometry (GC-MS) system. Results: The mean ages of the patients with leiomyomas and the control group were $43.1{\pm}5.6$ and $40.6{\pm}7.2$ years, the weights were $63.4{\pm}7.3$ and $59.4{\pm}8.1\;kg$, and their heights were $155.4{\pm}4.8$ and $159.3{\pm}4.8\;cm$ respectively. Seventeen patients had subserosal, 10 had intramural, and 10 had submucosal leiomyomas. There were 17 patients with leiomyoma located in fundus, 10 in body and 10 in isthmus. $17{\beta}$-estradiol, 5-AT, 11-keto ET, $11{\beta}$-hydroxy An, $11{\beta}$-hydroxy Et, THS, THA, THE, a-cortolone, a-cortol, $\beta$-cortol, $11{\beta}$-OH Et/$11{\beta}$-OH An and E2/E1 were significantly increased in patients with leiomyoma than in the control group. $17{\beta}$-estradiol was significantly increased in the intramural and the submucosal types than in the subserosal type. There was no significant difference in the concentrations of urinary steroids according to the locations of leiomyomas. There was no significant relationship between the concentration of urinary steroids and the volume of the leiomyomas. $17{\beta}$-estradiol significantly decreased as the weight of uterus increased (r=-0.322, p=0.04). Conclusion: The concentrations of steroid hormone metabolites were generally increased in patients with leiomyoma but were not significantly related to the volume and weight of the leiomyomas. Our study suggests that steroid hormones may be involved in the initiation of leiomyomas but may not be involved in their progression. In addition, the concentrations of steroid hormone metabolites are not related to the leiomyoma type and location.

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Studies on the Grape Wines (part II) - On the browing methods and the aging (포도주에 관한 연구 (제2보) - 포도주 양조방법 및 숙성촉진에 대하여)

  • Kim, Chan Jo;Kim, Seong Yeul;Oh, Man Jin
    • Korean Journal of Agricultural Science
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    • v.2 no.2
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    • pp.451-462
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    • 1975
  • The qualities of the grape wines brewed with the varieties of Steuben, Muscat Bailey A, Merlot, Campbell Early and Alden were compared, and studied the mashing methods of the wine with a variety of Muscat Bailey A. and then investigated the aging effects of ultrasonic wave and the baking treatments on the new wines. The results obtained were as follows. 1. Extracts of the new wines brewed with the varieties of Steuben and Alden were 2.55 and 1.88 per cent respectively and the color densities of the wines with Merlot and Alden were 3.5 and 1.05 (optical density) respectively, and the other contents were not significantly different beween varieties. On the Otherhand, the results of sensory test showed that the order of favorite was the wines brewed with Steuben, Muscat Bailey A, Merlot, Campbell Early and Alden. 2. The effect of pasteurization ($55^{\circ}C$, 20 min.) on the inhibition of the growth of undesirable microorganism was appeared almost the same degree as the case of sulfiting (100 ppm), and the pasteurized must was more dense in color but slightly turbid than the case of sulfiting. 3. Glucose syrup was in adequate as a materials for supplemental sugar, and the quality of the new wine further fermented the free-run wine added the alcohol to be a constant alcohol content was almost the same as that of control. 4. Baking at $50^{\circ}C$. for 50 days to t he new wine from 0.45 to 0.65 per cent, and color density was also thicken from 2.8 to 3.17 (O. D). 5. Baking at $40^{\circ}C$. for 50days to the new wine brewed with Muscat Bailey A, increased the ester content of the wine from 0.37 to 0.65 per cent and color density was-also thicken from 3. to 4.2 (O.D). 6. Ultrasonic wave (150 watt, 20Kc) treatment for 10 hours to the new wine brewed with Muscat Bailey A, increased the ester content of the wine from 0.37 to 0.47 per cent.

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Effect of Polymer, Calcium, Perlite and Chitosan in Soil Organic Amendment on Growth in Perennial Ryegrass (유기질 토양개량재에서 고분자 중합체, 칼슘, 펄라이트 및 키토산이 퍼레니얼 라이그래스의 생장에 미치는 효과)

  • Kim, Kyoung-Nam
    • Asian Journal of Turfgrass Science
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    • v.26 no.1
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    • pp.24-34
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    • 2012
  • The study was carried out to investigate the effects of polymer, calcium, perlite and chitosan on the growth of perennial ryegrass (Lolium perenne L., PR) and to provide a basic information needed for their practical application when establishing garden, parks, athletic field and golf courses with these materials. A total of 24 treatment combinations were applied in the study. Treatments were made of water-swelling polymer (WSP), calcium, perlite and chitosan mixed in soil organic amendment (SOA). Germination rate, turfgrass coverage, turfgrass density and top growth were evaluated in PR under greenhouse conditions. Significant differences were observed for these growth characteristics among the treatments. Turfgrass density and plant height, evaluated on a weekly basis, varied with time after seeding. A proper mixing rate of WSP was considered to be lower 3% for the growth of PR with an exception of being below 6% for turfgrass density. Germination rate and early survival capacity were greatly influenced by calcium and chitosan among the elements of calcium, perlite, and chitosan. But there was little effect by perlite. Calcium and chitosan were most effective one for turfgrass density and coverage, respectively. Top leaf-growth was influenced by all three elements, but the greatest effect was highly linked with calcium. Chitosan was very effective in early germination and vertical leaf growth, as compared with the others. Future studies are required for measuring the effect of WSP, calcium, perlite and chitosan on the turf growth characteristics in root zone mixtures of sand+SOA before a practical field use.

A Study on Actual Conditions for Prevention of Infections by Dental Hygienists (치과위생사의 감염 예방 실태 조사)

  • Nam, Young-Shin;Yoo, Jung-Sook;Park, Myung-Suk
    • Journal of dental hygiene science
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    • v.7 no.1
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    • pp.1-7
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    • 2007
  • This study aimed to provide basic information on dental hygienists' practicing the prevention of infections by figuring out their actual conditions in dental clinics. The subjects of the study were the dental hygienists who participated in the continuing medical education of Incheon & Gyeonggi-do association and Seoul city association in October and November 2005 and the self-administered surveys were used for the prevention of infections. The results were as below. 1. In terms of education experiences of infection prevention, those who answered "there were" were 72 persons (42.9%) and those who followed the educational route for infection prevention were "through the in-house education from the hospital" and they were 42 persons (58%), which were highest. 2. In terms of the injury experiences, those who answered "there were" were 147 persons (87.5%) and the number of annual injury out of 147 persons with injury experiences was 7.7 time. For the tools that were damaged, 125 persons (75%) damaged the "explorer," which was highest. 3. For the experiences of being infected with contagious diseases, those who answered "there were" were 6 persons (3.6%) and there were four persons for "hepatitis B", one person for "rubella" and one person for "TB." 4. The questions with high practice scores were as in the following: "2. I wash my hands after conducting medical examinations (1.86 points)," "7. I always close the lid of a shot of Novocain after doing local anesthesia (1.86 points)" and "20. I separate and collect the wastes and give them to those who treat accumulated materials (1.85 points)". Meanwhile, the questions with low practice scores were as below: "16. I change my medical gowns (doctor wears) once a day (0.24 point)" and "I wash my medical gowns every time after examining patients with contagious diseases (0.52 points)." 5. The question with high knowledge was as below: "1. The contagion during the dental treatment is determined by source of infection, infection methods, infection routes and the host that is prone to infection (0.95 point)" and the question with the lowest knowledge was "5. HBV(hepatitis B) is destroyed after adding 95oC of heat for more than 5 minutes (0.27 points)." 6. The question with the highest organization-related factors was "I am always ready to use a mask, gloves, etc. if necessary" (0.89 points)" and the question with the lowest score was "There is a guideline that I can refer when I am exposed to dangerous situations related to the contagion in my workplace (0.33 point)." 7. In terms of the equipment conditions of protectors in medical environments, 168 persons for (disposable) mask (100%), 167 persons for disposable gloves (Latex) (99.4%), which meant that most of them were equipped with them. On the contrary, 108 persons (64.3%) are equipped with the protectors for frontal faces, which is the lowest and 165 persons (98.2%) said that they had autoclave in their disinfecting and sterilizing devices.

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Channel Model and Wireless Link Performance Analysis for Short-Range Wireless Communication Applications in the Terahertz Frequency (테라헤르츠 대역 주파수에서 근거리 무선 통신 응용을 위한 채널 모델 및 무선 링크 성능 분석)

  • Chung, Tae-Jin
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.20 no.9
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    • pp.868-882
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    • 2009
  • In this paper, channel model and wireless link performance analysis for the short-range wireless communication system applications in the terahertz frequency which is currently interested in many countries will be described. In order to realize high data rates above 10 Gbps, the more wide bandwidths will be required than the currently available bandwidths of millimeter-wave frequencies, therefore, the carrier frequencies will be pushed to THz range to obtain larger bandwidths. From the THz atmospheric propagation characteristics based on ITU-R P.676-7, the available bandwidths were calculated to be 68, 48 and 45 GHz at the center frequencies of 220, 300 and 350 GHz, respectively. With these larger bandwidths, it was shown from the simulation that higher data rate above 10 Gbps can be achieved using lower order modulation schemes which have spectral efficiency of below 1. The indoor propagation delay spread characteristics were analyzed using a simplified PDP model with respect to building materials. The RMS delay spread was calculated to be 9.23 ns in a room size of $6\;m(L){\times}5\;m(W){\times}2.5\;m(H)$ for the concrete plaster with TE polarization, which is a similar result of below 10 ns from the Ray-Tracing simulation in the reference paper. The indoor wireless link performance analysis results showed that receiver sensitivity was $-56{\sim}-46\;dBm$ over bandwidth of $5{\sim}50\;GHz$ and antenna gain was calculated to be $26.6{\sim}31.6\;dBi$ at link distance of 10m under the BPSK modulation scheme. The maximum achievable data rates were estimated to be 30, 16 and 12 Gbps at the carrier frequencies of 220, 300 and 350 GHz, respectively, under the A WGN and LOS conditions, where it was assumed that the output power of the transmitter is -15 dBm and link distance of 1 m with BER of $10^{-12}$. If the output power of transmitter is increased, the more higher data rate can be achieved than the above results.

Effect of machining precision of single ceramic restorations on the marginal and internal fit (단일 도재 수복물의 가공 정밀도가 변연 및 내면 적합도에 미치는 영향)

  • Son, Keunbada;Yu, Beom-Young;Lee, Kyu-Bok
    • The Journal of Korean Academy of Prosthodontics
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    • v.58 no.4
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    • pp.313-320
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    • 2020
  • Purpose: The purpose of this study was to evaluate the machining precision and the marginal and internal fit of single restorations fabricated with three types of lithium disilicate ceramic blocks and to evaluate the correlation. Materials and methods: Single restorations were designed using a CAD software program. The crown designed model file was extracted from the CAD software program. Three types of lithium disilicate blocks (Rosetta; HASS, IPS e.max CAD; Ivoclar vivadent, VITA Suprinity; VITA) were milled using a milling machine. For the fabrication of the crown scanned model file, the intaglio surface of the restoration was digitized using a contact scanner. Then, using the three-dimensional inspection software (Geomagic control X; 3D Systems), the process of the overlap of the crown designed model and the scanned model and 3-dimensional analysis was conducted. In addition, the marginal and internal fit of the crowns was evaluated by a silicone replication method. The difference among three types of single ceramic crown was analyzed using a Kruskal-Wallis H test, and Spearman correlation analysis was performed to analyze the correlation between machining precision and fitness (α=.05). Results: There was a significant difference in the machining precision and the marginal and internal fit according to the type of ceramic block (P<.001). In addition, the machining precision and the marginal and internal fit were positively correlated (P<.001). Conclusion: The marginal fit of crowns fabricated according to the types of ceramic blocks was within the clinically acceptable range (< 120 ㎛), so it can be regarded as appropriate machining precision applicable to all clinical as aspects in terms of the marginal fit.

Elementary Teachers' Perception in Using Smart-Technology in STEAM Class : Focus on Application Type, Difficulties and Support Required (STEAM 수업에서 스마트테크놀로지 적용에 대한 초등교사의 인식 -적용 유형과 어려움 및 지원을 중심으로-)

  • Han, Areum;Na, Jiyeon
    • Journal of The Korean Association For Science Education
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    • v.39 no.6
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    • pp.777-790
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    • 2019
  • The purpose of this study is to investigate the experience of teachers who apply Smart-technology in elementary school STEAM class and the reasons, difficulties when applying the technology and required support. Semi-structured in-depth interviews were conducted with six elementary school teachers with specialized knowledge in STEAM education who have experienced STEAM lessons several times before. The research findings are as follows: First, research participants utilized a variety of Smart-technology in STEAM class, most of which were experiential or interactive technology. Among the STEAM learning criteria, the Smart-technology in 'Creative Design' course was most often applied. Second, they adopted Smart Technology in STEAM class to encourage students to feel interested, actively participate in the class, enjoy indirect experience, and nurture interest in state-of-the-art technology. They used it to prepare for future societies and organize classes that are suitable for STEAM learning criteria. They also used Smart-technology because it was easy to use. Third, they found it difficult to find, secure, and use suitable Smart-technology when applying Smart-technology in the STEAM class. They also had trouble restructuring the curriculum. In addition, there were difficulties in using Smart-technology in the class such as lack of class hours, increased level of activity, insufficient physical environment and unexpected malfunction of Smart-technology, thus interrupted the class. After the class, it was hard to manage Smart-technology and also, there were difficulties in assessment, record, and negative awareness of surrounding people. Fourth, they mentioned that's suggesting education guidelines, develop, and distribute educational materials are required to enable 'Creative Design,' reduce educational content, provide training, secure Smart-technology equipment and provide Wi-Fi, support teacher's club and communities and create an atmosphere to emotionally support teachers in order to activate using Smart-technology in STEAM class.