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        검색결과 31

        1.
        2023.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        DWI 검사 시 인체 조직 및 병변에 근접한 공기는 영상왜곡을 가중해 병변 감별에 어려움을 준다. 이에 본 연구는 팬텀을 제작하 여 기하학적 왜곡을 줄여주는 SMS RESOLVE DWI를 통해 공기 자화율에 의한 왜곡 변화를 정량화하였다. 팬텀은 원통형으로 내부에 공기가 존재하도록 설계하였다. 제한된 환경 속에서 다양한 자화율에 의해 왜곡이 영상에 구현되도록 팬텀 내부에는 증류수, 젤라틴 외 혼합 물질과 공기를 구분되게 채웠다. 팬텀의 정렬을 다르게 하여 공기 있는 상태 실험을 진행 후, 공기 대신 혼합액 넣은 상태 실험을 같은 방식으로 진행하였고 혼합액 대신 증류수 넣은 상태 실험을 진행하였다. 3T MRI 장비로 T2WI, C DWI, SMS-RESOLVE DWI를 촬영하였고 파이썬 OpenCV로 이미지 유사도를 측정 후 비교 분석하였다. 실험 결과 공기 있는 상태 SMS-RESOLVE DWI b0에서 SSIM 평균 0.898, MSE 평균 0.068로 영상왜곡이 가장 적었다. SMS-RESOLVE DWI의 공기 자화율 왜곡 변화는 b0 기준 SSIM, MSE 모두 –0.033~0.003 이미지 유사도 차이를 보였다. SMS-RESOLVE DWI b1000은 수치상 이미지 유사도 차이가 크지 않거나 감쇄되는 때도 있어서 향후 SNR 보완에 초점을 둔다면 보다 개선된 영상진단 성능을 제공할 것으로 기대되고 오픈 소스 라이브러리를 통해 오차를 최소화한 이미지 처리와 유사도를 분석하는 새로운 시도는 앞으로의 연구 방향에 새 모델을 제시한다.
        4,600원
        2.
        2022.10 구독 인증기관·개인회원 무료
        Radioactive mixed waste (RMW) is containing radioactive materials and hazardous materials. Radioactive wastes containing asbestos are include in RMW. These wastes thus must be treated considering both radioactive and hazardous aspects. In this study, a high temperature melt oxidation system consisting of an electric arc furnace and a molten salt oxidation furnace has been developed for the treatment of of radioactive waste containing asbestos. A surrogate waste of the radioactive waste containing asbestos (content of asbestos: 13wt%) was treated in this system. It was melted and fabricated into a glass waste form in the system. Asbestos was not detected in this glass waste form. This means that the asbestos was converted to a glass component in the glass waste form. The waste form was homogeneous glass, and it had a high value of compressive strength (475.13 MPa). It was also confirmed through a leaching test (ANS 16.1) that the waste form had a high chemical durability (Leaching Index > 6). Based on these results, it is considered that the high temperature melt oxidation system will be utilized for the treatment of a significant amount of radioactive waste containing asbestos generated from decommissioning a nuclear power plant.
        3.
        2022.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to examine the impacts of AI-integrated MALL on Korean students’ TOEIC preparation, by comparing with AI-integrated CALL. A total of 496 freshmen students participated in this study. They were arbitrarily assigned to AI CALL (n = 190), AI MALL (n = 164), and the control (n = 132) groups. During a 2021 academic semester, the two experimental groups studied TOEIC through computers or mobile phones, integrated with AI technology. The control group was taught by a human teacher, in a traditional classroom setting. Before and after the treatment, TOEIC listening and reading tests were administered. Paired samples t-tests and one-way ANOVAs, were used to analyze collected data. Findings show that all groups significantly increased listening and reading test scores. Group comparison results show that the AI CALL group outperformed the control group for both tests. This group also outperformed the AI MALL group for the reading test. Based on this, pedagogical implications are invaluable
        6,100원
        4.
        2022.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study is to determine whether the use of artificial intelligence (AI) improves English listening and reading proficiency. It focuses on whether its impacts differ by gender and major. The study was conducted in 2020 with 340 freshmen students in Korea. There were 182 male and 208 female students. The participants majored in different areas: 139 students majoring in aeronautics, 130 students studying policing and safety, 121 students studying in the arts department. The TOEIC test was adopted as pre- and post-tests to explore the impacts of using AI on English learning. To analyze the data, two-way ANOVAs were administered. The study found no interaction effects of gender or major on either listening and reading proficiency. However, gender and major, respectively, had significant impacts on listening. Regarding reading proficiency, major alone affected the students’ performance. Based on these findings, pedagogical implications are considered.
        7,000원
        5.
        2021.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This study explores effects of e-book and audio-book on EFL comprehension. It was conducted at a university in Korea with 75 college students. The whole experiment lasted for five weeks in 2020. To determine effectiveness of multiple modalities, participants were assigned to three different experimental groups: e-book, audio-book, and e-audio-book (a combination of e-book and audio-book) groups. While the e-book group was provided with passages in a text format, the audio group received the same passages in an audio format. The e-audio-book group was given both text and audio formats. At the beginning and end of the treatment, pretest and posttest were administered. As expected, the e-audio-book group benefited more than the other two groups in listening comprehension. However, they showed better performance in reading comprehension than the audio-book group only. Additionally, the e-book group performed better in reading comprehension compared to the audio-book group. Based on these findings, pedagogical implications are made.
        5,500원
        8.
        2020.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study focused on the perceptions of the use of different types of songs on Korean EFL students in language learning. For this study, two other variables, proficiency and gender, were also examined. In the study, 197 undergraduate students took part. All participants were taking an English course at a university in Korea. The three types of songs-pop songs, children’s songs, and movie songs-were used in class for nine weeks in 2019. A perception survey about stress, confidence, and interest in EFL learning was carried out. A one-way ANOVA was utilized to compare the participants’ perceptions and learning through the three different types of songs. Findings revealed significant difference between children’s songs and pop songs regarding stress. There were also significant differences in confidence and interest depending on proficiency levels. Participants’ gender also affected stress levels during the use of songs for English learning. This study shed light on the use of songs in the EFL context with a more comprehensive view of students’ reactions and preferences towards the different types of songs. Limitations of the study were suggested at the end of the paper.
        6,700원
        11.
        2019.04 구독 인증기관·개인회원 무료
        전라북도는 곤충사육농가의 77%인 121농가가 흰점박이꽃무지를 사육하고 있고 농가수의 증가가 예상됨에 따라, 생산단가를 절감시키면서 효율적인 사육을 위해서는 사육환경을 최적으로 유지하는 것이 매우 중요하다. 따라서 본 연구에서는 뽕나무발효톱밥을 이용하여 유충사육밀도에 따른 유충발육상황을 조사하였다. 최적 사육밀도 설정을 위하여 전라북도 사육농가에서 가장 많이 사용하는 20L 크기의 사육 상자에 각각 100, 125, 150, 175, 200마리 흰점박이꽃무지 유충을 넣고 뽕나무발효톱밥을 2/3정도 채운 후 사육하면서 유충무게변화, 생존율 등을 조사하였다. 부화 후 95일 흰점박이꽃무지 유충 생존율은 평균 81%로 사육밀도별 큰 차이가 없었다. 유충 무게는 100마리/20L 사육 시 2.219g로 가장 높게 나타났으며, 사육밀도가 증가함에 따라 감소하는 경향으로 나타났다. 유충 영양성분 조사결과 단백질 52.8g/100g, 지방 11.8g/100g이었으며, 중금속은 검출되지 않았다.
        12.
        2018.12 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        The objectives of this study were to find out the plant to enhance immune activity among 42 kinds of foods frequently consumed by the Korean elderly consisting of 5 food groups and 5 wild plants. Each sample was assessed the immunoactive effect by measuring NFkB/ AP1 gene expression, nitric oxide and cytokine production in RAW-Blue™ cell. Soybean sprouts of 47 plants showed the highest NF-κB/AP1 gene expression at the level of 1.13 ± 0.03 (O.D. 650 nm) and Soritae, sweet potato, banana, apple, garlic, crown daisy, cabbage and Ailanthus altissima also had high activity of NF-kB/AP1 gene in RAW-Blue™ cell stimulated by LPS. NO production of Ailanthus altissima was significantly higher than that of other plants and 16 plants of glutinous sorghum, black rice, Seoritae, Heuktae, sweet potato, banana, apple, garlic, mungbean sprouts, spinach, crown daisy, young pumpkin, cabbage, soybean sprouts, Actinidia arguta and Aster scaber were the next best activity. The above results selected 17 out of 47 plant samples. Moreover, soybean sprouts was significantly shown to increase TNF-α (1,509.55 ± 1.38 pg/mL) and IL-1β (54.56 ± 1.08 pg/mL) cytokines in comparison with RAW-Blue cell stimulated by LPS. According to the results of in vitro evaluation, the ethanol extract of soybean sprout increased the production of immune-enhancing cytokines by proliferation of macrophages. In addition, NF-kB transcription factor activity and NO production ability were excellent, and it was selected as a material having excellent immunological activity.
        4,200원
        14.
        2018.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study reports the effects of text chat on EFL students’ writing fluency, accuracy, and complexity, investigating whether its effects differ according to the interlocutor. The experimental design employed three text chat groups: one between two nonnative speakers (NNS-NNS); another between a nonnative speaker and a native speaker (NNS-NS); and the other between a nonnative speaker and a nativelike chatbot (NNS-NC). 78 college students of English as a foreign language between 19 to 22 years old were sampled and assigned into the three groups, each consisting of 30, 20, and 28, respectively. Over a 16-week period, they engaged in ten 10-minute-long chat sessions. All groups were tested before and after the treatment. A paired-samples t-test was conducted to compare preand post-test scores as far as fluency, accuracy, and complexity concerned. To find out the differences between mean scores of the groups, a one-way analysis of covariance (ANCOVA) was run. Results indicated that all three groups showed significant improvement in accuracy while only NNS-NS and NNS-NC groups did in fluency. No effects for complexity were evident. In terms of group differences, no statistical significance was detected. Participants’ perceptions of English learning and text chat positively changed overall. This study has pedagogical implications for EFL teachers, students, and researchers.
        6,700원
        19.
        2017.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The current study explores the effects of different types of voice-based chat on EFL students’ negotiation of meaning according to proficiency levels. Participants included 123 Korean university students of English. They were divided into two voice-based chat groups: student-student voice-based chat and student-chatterbot voice-based chat. The experiment was administered throughout one semester, 16 weeks. Negotiation of meaning evident in the chats was coded for confirmation check, comprehension check, clarification requests, repetition, and reformulation, and was measured by counting the number of meaning negotiation moves. Important findings were as follows: Firstly, there were significant differences between the first chat and the last chat. The mean frequencies of negotiation moves at all proficiency levels positively changed over time as a result of participating in student-chatterbot voice-based chat. Particulalry, student-chatterbot voice-based chat, as compared to student-student voice-based chat, allowed students to use more negotiation strategies, and the strategies used in the chats also appeared to be different according to the students’ proficiency levels. Lastly, positive perceptions of voice-based chat were observed at all proficiency levels. This study provides empirical evidence to substantiate the effects of voice-based chatterbots in oral interaction. Based on the findings, pedagogical implications are made on the effective implementation of voice-based chatterbots in EFL contexts.
        6,000원
        20.
        2017.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        사용후핵연료 파이로프로세싱에서는 방사성 희토류 염화물(RECl3)을 함유한 LiCl-KCl 공융염폐기물이 발생되며, 핫셀시설에서 운영을 목적으로 단순한 형태의 공융염폐기물 처리공정을 개발하는 것이 필요하다. 본 연구에서는, LiCl-KCl 공융염폐기물 내 희토류 핵종 분리/고화공정의 단순화를 목적으로 Li2O-Al2O3-SiO2-B2O3계의 무기합성매질을 이용하여 LiCl-KCl 공융 염 내 희토류 핵종(Nd)을 분리한 후 분리생성물을 바로 고화하는 시험을 실시하였다. 공융염 내 희토류 염화물(NdCl3) 대비 0.67의 무게비에 해당하는 무기합성매질의 양으로도 Nd 핵종을 98wt% 이상 분리할 수 있었고, 이 때 얻은 희토류 핵종 포집생성물은 약 50wt% 수준의 희토류 산화물 함량을 보유하고 있었으며, 이 포집생성물을 화학적 내구성이 우수한 단일상의 균질한 유리고화체로 제조할 수 있었다. 이 결과들은 LiCl-KCl 공융염폐기물 내 희토류 핵종의 분리/고화공정을 단순화하기 위한 방안수립에 활용될 수 있을 것이다.
        4,000원
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