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Comparison of the Rate of Demineralization of Enamel using Synthetic Polymer Gel (합성 폴리머 겔의 법랑질 탈회 속도 비교)

  • Lee, June-Hang;Shin, Jisun;Kim, Jongsoo
    • Journal of the korean academy of Pediatric Dentistry
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    • v.46 no.2
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    • pp.190-199
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    • 2019
  • $Carbopol^{(R)}$ 907 used as surface protecting agent in White's method is the one of the artificial caries lesion producing solution was discontinuing of production. New surface protecting material to substitute of $Carbopol^{(R)}$ 907 was required. The author prepared an artificial caries lesion producing solution as follows White's method with $Carbopol^{(R)}$ 907 and also another artificial caries lesion producing solution with $Carbopol^{(R)}$ $2050^{(R)}$. 96 flattened and polished enamel samples were immersed in a demineralizing solution of 0.1 mol/L lactic acid, 0.2% carboxyvinylpolymer and 50% saturated hydroxyapatite for 1, 2, 3, 4, 5, 6, 7, 9, 11, 15, 18 and 20 days. All samples from each group were subjected to polarized microscopy observed and image analysis for measuring the lesion depth. From the review of polarized images, the artificial caries lesion producing solution using $Carbopol^{(R)}$ 907 and $Carbopol^{(R)}$ 2050 can produced an artificial caries that was very similar to natural caries characters. From the regression analysis of the lesion depth produced by the artificial caries lesion producing solution using $Carbopol^{(R)}$ 907 and $Carbopol^{(R)}$ 2050, $Carbopol^{(R)}$ 2050 estimate as Y = 9.8X + 8.0 and $Carbopol^{(R)}$ 907 was Y = 8.4X - 0.4. R square value of $Carbopol^{(R)}$ 2050 and $Carbopol^{(R)}$ 907 was 0.965 and 0.945 respectively. The rate of demineralization by the artificial caries lesion producing solution using $Carbopol^{(R)}$ 2050 was faster than that of $Carbopol^{(R)}$ 907. And R square value of $Carbopol^{(R)}$ 2050 and $Carbopol^{(R)}$ 907 were very high and it means that the lesion depth was very high coefficient to demineralization period.

Distribution and Conservation plan of Vascular Plants in Outstanding Forest Wetlands in Jeonnam Area (전남권역 우량 산림습원의 관속식물상 변화 및 보전방안)

  • Lee, Jong-Won;Yun, Ho-Geun;Kang, Shin-Ho;An, Jong-Bin
    • Journal of Wetlands Research
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    • v.24 no.4
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    • pp.224-255
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    • 2022
  • This study was carried out to examine the changes in vascular flora in the first and second surveys targeting 32 outstanding forest wetlands in Jeonnam area including Gwangju metropolitan city, and based on this, establish a future monitoring system and effectively manage the excellent forest wetlands. The survey investigated the area seasonally every 4-5 years from 2015 to 2021. The change of flora of 32 excellent forest wetlands in Jeollanam-do increased from 103 families, 311 genera, 496 species, 16 subspecies, 38 varieties, 6 varieties, 556 taxa, to 111 families, 362 genera, 599 species, 16 subspecies, 51 varieties, 8 varieties, 674 taxa. Remarkable plants such as Red list and plants endemic to the Korean Peninsula increased also. However, Nepeta cataria and the like are exterminated locally, so an in situ and ex situ conservation strategy must be established. In the case of plants categorized according to wetland preference, the distribution ratio of such wetland plants slightly decreased and the distribution ratio of such terrestrial plants lightly increased for absolute wetland plants. It is necessary to prepare countermeasures for the terrestrialization of forest wetlands and to develop research techniques that can distinguish boundaries. In addition, the forest wetland should be systematically managed and supervised by designating it as a Forest Genetic Resources Reserve that can effectively conserve it.

An Analysis Study of Deliberation Results to Change the Present Condition around Gyeonggi-do Designated Cultural Properties - Focusing on the Proposed Legislation 3 or More Times a Deliberations of the Cultural Properties Committee - (경기도지정문화재 주변 현상변경허가 신청안 심의결과에 관한 분석 연구 - 문화재위원회심의 3회 이상 상정안을 중심으로 -)

  • Lim, Jin-Kang;Kim, Dong-Chan
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.29 no.3
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    • pp.85-96
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    • 2011
  • The purpose of this study, Around Gyeonggi-do cultural propertie Change the Present Condition not apply to analyze the results of processing Change the Present Condition of the trends and issues, and characteristics are derived and In determining the basic data processing of the Change the Present Condition presented are intended to be. 248 of 2009 regulated by Gyeonggi-do Cultural Assets committee agenda for consideration of the more than three times a copy of 15 were enrolled in the study. Review the results of the Change the Present Condition permit, permit held, to review classified information and analyzes the results of processing and complementary. Application for change processing standards and their comparison with the Change the Present Condition of cultural property through the deliberations and conclusions should analyze the results. As a result of research first, decision to allow processing of the application is characterized by a variety of facilities and the lower floors many times the result of the approval, the construction of cultural property conditioned space after the application complements the exterior of the building permit has been determined, applied to the current building near where the decision to allow the existence of is the main reason Second, decisions permit held, if requested neighborhood facilities lots of facilities and construction of large-scale is the most. Results from the first hearing until a final decision is not much change in results and cultural property surroundings due to the building of the reason for rejection was the most inhibited. Third, reconsideration of the decision if the city's development projects and other large development projects, and floors of the building height did not significantly affect the change. Above all, Decisions based on the results of the presence or absence was a big acts and the reason for reconsideration, and on-site investigation is the most. Fourth, It is based on the processing of Change the Present Condition that has been passed or rejected treatment and standards of treatment in two areas where the two sections across any side of the strict criteria were applied. Cultural Properties and applications with the distance increases, the rejection and the reconsideration decision is limited Such distance did not affect the decision to allow.

A Study on the theory of Mind in LüZuqian(呂祖謙) philosophy (여조겸(呂祖謙) 심론(心論) 연구(硏究) : 여조겸과 주희의 사상적 대립과 절충)

  • Yeon, Jae-heum
    • The Journal of Korean Philosophical History
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    • no.38
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    • pp.63-96
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    • 2013
  • $L{\ddot{u}}Zuqian$(呂祖謙) was one of the famous philosophers during the Southern Song period, and is called one of DongNamSanXian(東南三賢) together with ZhuXi(朱熹) and ZhangShi(張?). With his profound knowledge transmitted and uphold by JiaXue(家學), $L{\ddot{u}}Zuqian$(呂祖謙) established his learning system, interacting with scholars of those days. Principally, $L{\ddot{u}}Zuqian$(呂祖謙)'s XinLun(心論) was based on Mengzi(孟子)' theory of LiangXin(良心) and BenXin(本心). $L{\ddot{u}}Zuqian$(呂祖謙) explained the meaning of such a conscience through ChuXin(初心) and Inner NeiXin(內心). According to $L{\ddot{u}}Zuqian$(呂祖謙), ChuXin(初心) arouses when one encounters external things, and this one's intention enables us to make the right judgments over the outside objects. NeiXin(內心) means LiangXin(良心) and BenXin(本心) that recovered the ability of moral awareness. The important significances of $L{\ddot{u}}Zuqian$(呂祖謙)'s XinLun(心論) are XinWai WuDao(心外無道), and XinWaiWuTian(心外無天). Through these, $L{\ddot{u}}Zuqian$(呂祖謙) emphasized that Tian(天), Dao(道), and Li(理) are one. $L{\ddot{u}}Zuqian$(呂祖謙) arranged a meeting of EHuSi(鵝湖寺), and exerted efforts to negotiate the academic differences between ZhuXi(朱熹) and LuJiuyuan(陸九淵). However, compared with LuJiuyuan(陸九淵) who asserted FaMingBenXin(發明本心), $L{\ddot{u}}Zuqian$(呂祖謙) put the emphasis on DaoWenXue(道問學) with self-awareness of conscience. Meanwhile, $L{\ddot{u}}Zuqian$(呂祖謙) valued much of Jing(敬) like ZhuXi(朱熹). But, to $L{\ddot{u}}Zuqian$(呂祖謙), Jing(敬) meant WuJianDuan(無間斷) of ChunYiBuZa(純一不雜) DaoDeXin(道德心), and implied the same as Cheng(誠). $L{\ddot{u}}Zuqian$(呂祖謙) stressed the reading and pursuit of study, however, he also asserted that Li(理) could be understood and realized through self-awareness of one's mind and its reflection, and working without interruption. $L{\ddot{u}}Zuqian$(呂祖謙)'s academic tradition of the XinXueDe XueFeng(心學的 學風), which reveals through compromise and confrontation with ZhuXi(朱熹), can be said that it will have a significant meaning of idealism of dispute in the Southern Song period.

Development and Validation of a Simultaneous Analytical Method for 5 Residual Pesticides in Agricultural Products using GC-MS/MS (GC-MS/MS를 이용한 농산물 중 잔류농약 5종 동시시험법 개발 및 검증)

  • Park, Eun-Ji;Kim, Nam Young;Shim, Jae-Han;Lee, Jung Mi;Jung, Yong Hyun;Oh, Jae-Ho
    • Journal of Food Hygiene and Safety
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    • v.36 no.3
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    • pp.228-238
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    • 2021
  • The aim of this research was to develop a rapid and easy multi-residue method for determining dimethipin, omethoate, dimethipin, chlorfenvinphos and azinphos-methyl in agricultural products (hulled rice, potato, soybean, mandarin and green pepper). Samples were prepared using QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) and analyzed using gas chromatography-tandem mass spectrometry (GC-MS/MS). Residual pesticides were extracted with 1% acetic acid in acetonitrile followed by addition of anhydrous magnesium sulfate (MgSO4) and anhydrous sodium acetate. The extracts were cleaned up using MgSO4, primary secondary amine (PSA) and octadecyl (C18). The linearity of the calibration curves, which waas excellent by matrix-matched standards, ranged from 0.005 mg/kg to 0.3 mg/kg and yielded the coefficients of determination (R2) ≥ 0.9934 for all analytes. Average recoveries spiked at three levels (0.01, 0.1, 0.5 mg/kg) and were in the range of 74.2-119.3%, while standard deviation values were less than 14.6%, which is below the Codex guideline (CODEX CAC/GL 40).

Quality Properties and Antioxidant Activities of Korean Traditional Rice-Based Wine, Makgeolli Added with Sweet Pumpkin (단호박을 첨가하여 제조한 막걸리의 품질특성 및 항산화 활성)

  • Kim, Ji Yoon;Song, Min Gyu;Jeon, Eun Bi;Park, Shin Young
    • Journal of Food Hygiene and Safety
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    • v.36 no.3
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    • pp.271-279
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    • 2021
  • Sweet pumpkin is rich in minerals such as calcium, phosphorus and fiber, and also contains a large amount of β-carotene, which has antioxidant effects. In this study, Makgeolli containing steaming sweet pumpkin (SP) was manufactured to enhance the antioxidant activity. To prepare the Makgeolli, SP was added in amounts of 5, 10, 20, and 30% (w/w), and the chemical (pH, total acidity, alcohol), microbiological (lactic acid bacteria, yeast) properties, and antioxidant activities (DPPH, ABTS) were examined during fermentation and storage for 9 days. The pH of SP Makgeolli was 4.00-4.23 at day 1 of fermentation, and then the pH gradually decreased as fermentation progressed, showing the lowest results at day 9 (3.28-3.52). At day 1, the total acidity was significantly increased (P<0.05) as the amount of SP (0-30%; 0.09-0.55%) and the total acidity in SP Makgeolli (1.01-1.20) was also rapidly increased by 5 days of fermentation. Alcohol content was significantly increased (P<0.05) as the amount of SP (0-30%; 4.59-5.77%) increased at day 9. The counts of lactic acid bacteria and yeast in SP Makgeolli were 8.0-8.1 and 7.9-7.8.0 CFU/mL, respectively, which was higher than SP 0% at day 9. DPPH and ABTS radical scavenging activities were significantly increased (P<0.05) as the amount of SP (0-30%; 48.29-78.97% for DPPH, 62.12-86.68% for ABTS) increased at day 9. This study suggests that Makgeolli added with SP could be potentially and commercially developed due to its superior microbiological and chemical properties, including high antioxidant activities.

Analysis of the basic items and safety accidents occurring during the fishing operation in coastal improved stow net fishery by the questionnaire survey (설문조사를 통한 연안개량안강망어업의 기본 사항 및 어로 작업 중 발생하는 안전사고 분석)

  • CHANG, Ho-Young;KIM, Min-Son;HWANG, Bo-Kyu;OH, Jong Chul
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.57 no.1
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    • pp.57-68
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    • 2021
  • In order to collect basic data for the improvement of fishing systems in coastal improved stow net fishery, a questionnaire survey and on-site hearing were conducted from May 10 to June 11, 2019 on the basic items of coastal improved stow net fishery and safety accidents that occurred during fishing operation. The questionnaire for the survey on the actual conditions of coastal improved stow net fishery consisted of a survey on basic matters (six questions) and a questionnaire (six questions) on safety accidents occurring during fishing operation. The results of the survey on basic items were analyzed by region (Incheon, Seocheon, Gunsan and Mokpo), by the captain's age (less than 50 years of age, 50 to 60 years and more than 60 years of age), by the captain's career (less than 20 years, 20 to 30 years, 30 to 40 years and more than 40 years) and by the age of fishing vessel (less than 10 years, 10 to 20 years and more than 20 years). According to the survey on basic items of coastal improved stow net fishery such as the captain's age, the captain's career, the age of fishing vessel, the fishing nets in use, the crews on board and the operation days per voyage by region, the average captain's age was 55.7 years, the average captain's career was 20.5 years, the average age of fishing vessels was 9.0 years, the average numbers of nets used by fishing boats was 14.0 sets, the average numbers of crew on board a fishing boat was 4.4 persons and the average numbers of operation days per voyage was 4.9 days (p < 0.05). As a result of the survey on safety factors during fishing operations, such as experience of ship accidents, major causes of ship accidents experienced, causes of ship accidents (first priority), experience of human accidents, major causes of human accidents, and causes of human accidents (first priority), more than 96% of the respondents experienced ship accidents including collisions with other vessels or fishing gear during fishing operations. The most significant cause of the accident was the other's fishing gear installed in the fishing grounds. The first possible causes of ship accidents during fishing operations were found to be other fishing gear installed in fishing grounds, steering or engine failure, and inability to avoid accidents during casting and hauling nets. The survey of the experience of human accidents, such as injuries or sea falls, showed that more than 90% of the respondents experienced human accidents during fishing operations. The most important cause of accidents experienced during fishing operations was stucked in a fishing gear during casting and hauling nets. The first important causes of accidents during fishing operations were movement of the fishing gear during casting and hauling nets, damage of the fishing gear such as rope cutting. The results are expected to be provided as a basic data to prevent safety accidents occurring during fishing operation and improve the fishing system in the coastal improved stow net fishery.

Performance of Investment Strategy using Investor-specific Transaction Information and Machine Learning (투자자별 거래정보와 머신러닝을 활용한 투자전략의 성과)

  • Kim, Kyung Mock;Kim, Sun Woong;Choi, Heung Sik
    • Journal of Intelligence and Information Systems
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    • v.27 no.1
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    • pp.65-82
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    • 2021
  • Stock market investors are generally split into foreign investors, institutional investors, and individual investors. Compared to individual investor groups, professional investor groups such as foreign investors have an advantage in information and financial power and, as a result, foreign investors are known to show good investment performance among market participants. The purpose of this study is to propose an investment strategy that combines investor-specific transaction information and machine learning, and to analyze the portfolio investment performance of the proposed model using actual stock price and investor-specific transaction data. The Korea Exchange offers daily information on the volume of purchase and sale of each investor to securities firms. We developed a data collection program in C# programming language using an API provided by Daishin Securities Cybosplus, and collected 151 out of 200 KOSPI stocks with daily opening price, closing price and investor-specific net purchase data from January 2, 2007 to July 31, 2017. The self-organizing map model is an artificial neural network that performs clustering by unsupervised learning and has been introduced by Teuvo Kohonen since 1984. We implement competition among intra-surface artificial neurons, and all connections are non-recursive artificial neural networks that go from bottom to top. It can also be expanded to multiple layers, although many fault layers are commonly used. Linear functions are used by active functions of artificial nerve cells, and learning rules use Instar rules as well as general competitive learning. The core of the backpropagation model is the model that performs classification by supervised learning as an artificial neural network. We grouped and transformed investor-specific transaction volume data to learn backpropagation models through the self-organizing map model of artificial neural networks. As a result of the estimation of verification data through training, the portfolios were rebalanced monthly. For performance analysis, a passive portfolio was designated and the KOSPI 200 and KOSPI index returns for proxies on market returns were also obtained. Performance analysis was conducted using the equally-weighted portfolio return, compound interest rate, annual return, Maximum Draw Down, standard deviation, and Sharpe Ratio. Buy and hold returns of the top 10 market capitalization stocks are designated as a benchmark. Buy and hold strategy is the best strategy under the efficient market hypothesis. The prediction rate of learning data using backpropagation model was significantly high at 96.61%, while the prediction rate of verification data was also relatively high in the results of the 57.1% verification data. The performance evaluation of self-organizing map grouping can be determined as a result of a backpropagation model. This is because if the grouping results of the self-organizing map model had been poor, the learning results of the backpropagation model would have been poor. In this way, the performance assessment of machine learning is judged to be better learned than previous studies. Our portfolio doubled the return on the benchmark and performed better than the market returns on the KOSPI and KOSPI 200 indexes. In contrast to the benchmark, the MDD and standard deviation for portfolio risk indicators also showed better results. The Sharpe Ratio performed higher than benchmarks and stock market indexes. Through this, we presented the direction of portfolio composition program using machine learning and investor-specific transaction information and showed that it can be used to develop programs for real stock investment. The return is the result of monthly portfolio composition and asset rebalancing to the same proportion. Better outcomes are predicted when forming a monthly portfolio if the system is enforced by rebalancing the suggested stocks continuously without selling and re-buying it. Therefore, real transactions appear to be relevant.

Microbial Qualities of Parasites and Foodborne Pathogens in Ready to Eat (RTE) Fresh-cut Produces at the On/Offline Markets (즉석섭취 신선편의 절단 과일 및 채소의 원충류 및 병원성 식중독균의 미생물학적 품질 실태 연구)

  • Jeon, Ji Hye;Roh, Jun Hye;Lee, Chae Lim;Kim, Geun Hyang;Lee, Jeong Yeon;Yoon, Ki Sun
    • Journal of Food Hygiene and Safety
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    • v.37 no.2
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    • pp.87-96
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    • 2022
  • Recently, the purchase of fresh-cut produce and meal kits has increased. Ready-to-eat (RTE) fresh-cut products have potentially hazard of cross-contamination of various microorganisms in the processes of peeling, slicing, dicing, and shredding. There are frequent cases of protozoa food poisoning, such as Cyclospora and Cryptosporidium, caused by fresh-cut products. The objective of the study is to investigate the microbiological qualities of various types of RTE fresh-cut products in the domestic on/offline markets. RTE fresh-cut fruits cup (n=100), fresh-cut vegetables (n=50), and vegetables in meal kits (Vietnamese spring rolls and white radish rolls kits, n=50) were seasonally analyzed. The contamination levels of hygienic indicator organisms, yeast and mold (YM), and foodborne pathogens (Bacillus cereus, Staphylococcus aureus, Listeria monocytogenes, Salmonella spp., and Escherichia coli O157:H7) were monitored. Overall, the lowest microbiological qualities of meal kits vegetables were observed, followed by RTE fresh-cut fruits cup and fresh-cut vegetables. Contamination levels of total aerobic bacteria, coliforms, and YM in meal kits vegetables were 5.91, 3.90, and 4.71 logs CFU/g, respectively. From the qualitative analysis, 6 out of 200 RTE fresh-cut products (3%) returned positive result for S. aureus. From the quantitative analysis, the contamination levels of S. aureus in purple cabbage from a meal-kit and fresh-cut pineapple were below the acceptable limit (100 CFU/g). Staphylococcus enterotoxin seg and sei genes were detected in RTE fresh-cut celery and red cabbage from meal-kits, respectively. S. aureus contamination must be carefully controlled during the manufacturing processes of RTE fresh-cut products. Neither Cyclospora cayetanensis nor Cryptosporidium parvum was detected in the samples of RTE fresh-cut products and vegetables from meal-kits from the Korean retail markets.

Identification and Chemotype Profiling of Fusarium Head Blight Disease in Triticale (국내 재배 트리티케일에 발생한 붉은곰팡이병의 다양성 및 독소화학형 분석)

  • Yang, Jung-Wook;Kim, Joo-Yeon;Lee, Mi-Rang;Kang, In-Jeong;Jeong, Jung-Hyun;Park, Myoung Ryoul;Ku, Ja-Hwan;Kim, Wook-Han
    • Research in Plant Disease
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    • v.27 no.4
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    • pp.172-179
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    • 2021
  • This study aimed to assess the disease incidence and distribution of toxigenic in Korean triticale. The pathogen of triticale that cause Fusarium head blight were isolated from five different triticale cultivars that cultivated in Suwon Korea at 2021 year. The 72 candidate were classified as a Fusarium asiaticum by morphology analysis and by ITS1, TEF-1α gene sequence analysis. And the results of pathogenicity with 72 isolates on seedling triticale, 71 isolates were showed disease symptom. Also, seven out of 71 Fusarium isolates were inoculated on the wheat, to test the pathogenicity on the different host. The results showed more low pathogenicity on the wheat than triticale. The results of analysis of toxin type with 72 isolates, 64.6% isolates were produced nivalenol type toxin and other 4.6% and 30.8% isolates were produce 3-acetyldeoxynivalenol and 15-acetyldeoxynivalenol, respectively. To select fungicide for control, the 72 Fusarium isolates were cultivated on the media that containing four kinds fungicide. The captan, hexaconazole, and difenoconazole·propiconazole treated Fusarium isolates were not showed resistance response against each fungicide. However, six isolates out of 72 isolates, showed resistance response to fludioxonil. This study is first report that F. asiaticum causes Fusarium head blight disease of triticale in Korea.