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        검색결과 4,600

        21.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 생성형 인공지능인 챗봇을 활용해서 핵심광물을 탐구하는 과정에서 나타나는 챗봇과 학생의 반응, 그 들 사이에서 일어나는 상호작용을 인식론적 측면에서 분석했다. 그 결과를 바탕으로 인공지능을 활용한 교수·학습 과정 에서 유의해야 할 문제들을 교사의 역할, 교육의 목표, 지식의 속성 측면에서 논의했다. 이 연구를 위해 고등학생 19명 을 대상으로 챗봇을 활용한 3차시 과학 교육 프로그램을 진행했고, 학생들이 작성한 보고서를 분석했다. 그 결과, 학생 의 질문은 형식적 측면에서 검색형 질문과 탈검색형 질문이 나타났고 내용적 측면에서는 대상에 대한 특성을 묻는 다 양한 질문 외에도 여러 자료를 종합해서 판단할 것을 요구하는 질문도 나타났다. 대체로 학생들은 지향해야할 것과 지 양해야 할 것을 구분한 질문 전략을 갖추고 있었다. 챗봇의 답변은 일정한 형태-서문, 본문, 결문 등의 3부분으로 이루 어져 있었고, 특히 결문에는 내용에 대한 의견을 곁들인 논평이나 의견 등이 포함되어 있어서 여기에는 가치 판단과 함께 과학의 본성이 나타났다. 챗봇과 학생의 상호작용은 학생이 챗봇의 답변에 대한 질문을 조직하는 과정에서 잘 드 러났다. 답변 근거 여부에 따라 독립형, 파생형 질문으로, 포괄성 수준의 변화에 따라 상위형, 하위형, 병렬형 질문이 나타나기도 했다. 학생들은 챗봇의 답변에 비판적 사고기술이 포함된 질문으로 반응하기도 했다. 이러한 결과를 바탕으 로 챗봇과 학생 사이에는 교사와 상호작용하는 일반적 수업과 달리 ‘제한된 상호작용’이라는 태생적 한계가 있음을 발 견하고 이를 보완할 교사의 역할을 논의했고, 아울러 AI를 활용한 학습의 목표 및 이들이 제공하는 지식의 속성을 함 께 논의했다.
        5,200원
        22.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was performed to investigate antioxidant and anti-inflammatory activities of perilla(Perilla frutescens L.) seed, flower and leaf according to extraction condition. Perilla seed extracts(PSE), perilla flower extracts(PFE), perilla leaf extracts(PLE) was extracted by stirring extraction (STE, 25°C), shaking extraction (SHE, 80°C), and sonication assisted extraction(SAE, , 25°C) with 94% ethanol, 60% ethanol and distilled water, followed by analysis of total polyphenol and flavonoid and testing radical scavenging activities. The highest total polyphenol content (5.47, 9.36, 38.58 mg gallic acid equivalent/g), total flavonoid content(5.77, 8.62, 46.44 mg catechin equivalent/g), ABTS(10.68, 19.46, 63.56 mg trolox equivalent/g) and DPPH(6.51, 7.69, 79.73 mg trolox equivalent/g) radical scavenging activity of PSE, PFE and PLE was observed in the HWE with 60% ethanol,. Among the three extraction method, SHE provided the best results for yield, polyphenol, flavonoid content of perilla seed, flower, leaf in comparison to STE or SAE. SHE with 60% ethanol of perilla seed, flower, leaf more effectively inhibited secretion of nitric oxide(NO) and pro-inflammatory cytokine in RAW 264.7 macrophage exposed to LPS compared to other extraction solvent and method. Therefore, these extracts obtained from perilla seed, flower, leaf could be used antioxidant and anti-inflammatory ingredients in the food industry.
        4,000원
        23.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated the quality characteristics and antioxidant activities of salad dressing prepared with Jerusalem artichoke powder (0%, 4%, 8%, and 12%). The pH, soluble solid content, and viscosity increased as the content of Jerusalem artichoke powder increased. The titratable acidity showed no significant differences between samples. The lightness values decreased, while the redness and yellowness values increased with increasing amounts of Jerusalem artichoke powder. The total polyphenol content ranged from 52.00-69.64 μg GAE/g, and increased with the increase in Jerusalem artichoke powder levels. The antioxidant activities measured via DPPH and ABTS radical scavenging activity and reducing power also increased with increasing Jerusalem artichoke powder, at a higher rate than in the control. These results suggest that it is beneficial to add Jerusalem artichoke powder when in salad dressing.
        4,000원
        24.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        고성능 분리막 제조기술과 더불어 새로운 분리막 다단공정 설계를 통해 용매사용량 감소 및 선택도 향상이 가능 하다. 본 연구에서는 내용매성 셀룰로스 나노분리막을 제조하여 용매에 따른 용질의 선택도 차이를 비교하였다. 제막한 셀룰 로스 막을 기반으로 비극성 용매의 선택도 평가를 진행하였으며, 비극성 용매에서 용질에 대한 음배제율이 관측되었다. 특히, 분자량이 클수록 음배제율이 높아지는 역선택도의 거동을 확인하였다. 이를 기반으로 설계한 공정에서는 기존 분획 공정 대 비 3배 이상의 용매저감이 가능한 것을 확인할 수 있었다.
        4,000원
        25.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study aimed to investigate the dietary changes among adults living alone during the COVID-19 pandemic in the Republic of Korea. An online survey was conducted to examine dietary changes before (in 2019) and during (in 2021) the pandemic. The data from 337 adults living alone who responded to the survey were used for analysis. The proportion of the respondents reporting frequent food consumption at convenience stores (≥3 times/week) increased during the pandemic (p=0.024), and the proportion of those frequently eating ready-to-eat and ready-to-cook food (≥3 times/week) was more than doubled (p<0.001). Additionally, the proportion of those frequently consuming delivered food (≥3 times/week) increased by 2.5 times (p<0.001). In conclusion, the dietary habits of adults living alone changed significantly during the COVID-19 pandemic, which may have a negative impact on their health. Therefore, the development of customized nutrition management programs to improve the dietary habits of adults living alone during emergencies like a pandemic is deemed necessary. This study can serve as a foundation for understanding the dietary changes of adults living alone in prolonged crisis.
        4,000원
        26.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study analyzed the monitoring results of fishways at 16 weirs constructed on four large Rivers to provide data helpful for the operation and management of fishways. The average utilization rate of the fishways at the weirs was confirmed to be 64.9%. When comparing the dominant species in the mainstream and fishway monitoring results, differences were observed in 9 weirs (56.3%). This indicated that the species prevalent in the mainstream were not necessarily the ones most frequently using the fishways. The average number of individuals using the fishways per day was 336. When classifying the fish species using the fishway by life type, 92.3% were primary freshwater fish, and migratory species accounted for only 5.6%. Analysis based on the season of fishway usage revealed that an average or higher number of fish species used the fishways from May to October, with the highest number of individual users occurring from June to August. Between May and July, 80% of the fish species using the fishways were in their spawning period, while during other season, less than 40% were species that move during the spawning period. The fishways that showed a significant alignment between the spawning period and the fishway passage period were Rhinogobius brunneus, Leiocassis nitidus, Squalidus chankaensis tsuchigae, Pseudogobio esocinus, Acheilognathus rhombeus, and Pungtungia herzi, in that order. When comparing the fishway monitoring results of the Gangjeong-Goryeong Weir and the Dalseong Weir with the upper part water level of the weir, both the number of fish species and individuals using the fishway showed positive correlations with the upper part water level of the weir. This suggests that a higher water level of the weir increases the inflow discharge within the fishway, leading to increased use by fish (number of individuals in Gangjeong-Goryeong Weir, P<0.001; number of species in Dalseong Weir, P<0.05). This study summarized and analyzed the results of fishway monitoring at 16 weirs built on four large Rivers, considering fishway efficiency, operation and management, monitoring period, and regulation of water level in the upper part of the weir. It is thought that this will help understand the status of fish use in fishways on large River and aid the construction, operation, and management of fishways in the future.
        4,800원
        27.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        좁은가슴잎벌레는 십자화과작물을 가해하는 해충으로 알려져 있다. 본 연구는 온도가 좁은가슴잎벌레의 발육단계별 발육기간, 성충의 수 명과 산란특성에 미치는 영향을 파악하고자 성충 전 발육단계는 15, 20, 25, 27.5°C에서, 성충은 10, 15, 20, 25, 27.5°C 항온조건에서 조사하였 다. 알과 유충은 항온조건에서 다음 발육 단계로 성공적으로 발육하였다. 알, 유충, 번데기의 발육기간은 온도가 상승할수록 짧아지는 경향을 보 였다. 좁은가슴잎벌레의 발육영점온도, 유효적산온일도는 선형회귀분석을 통해 추정하였으며 알에서 성충출현까지 발육영점온도와 유효적산온 일도는 8.7°C와 344.73DD였다. 좁은가슴잎벌레 발육단계별 최저, 최고 온도의 한계는 Briere함수를 이용하여 추정하였으며 알에서 성충출현 까지 최저, 최고한계는 5.3°C와 40.4°C였다. 성충은 10°C와 27.5°C 범위에서 산란이 가능하였고 21.7°C에서 최대 약 627.5개의 알을 낳는 것 으로 추정되었다. 노화율, 나이별 생존율, 나이별 누적산란율, 온도의존 산란수와 관련된 성충모델들을 작성하였다. 본 연구에서 제시한 온도발육 모형과 성충산란모형은 좁은가슴잎벌레 개체군동태를 이해하는데 유용할 것이며 십자화과작물의 종합적 해충군관리체계를 마련하는데 기초자 료로 활용될것으로 기대된다.
        4,000원
        28.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        For the past 70 years, an intense rivalry has persisted on the Korean Peninsula, and North Korea's nuclear and missile threats are becoming increasingly imminent. Facing a shortage of military resources, South Korea has pursued a national defense reform, significantly reducing the number of units and troops while focusing on ground forces. However, North Korea's strategic objective of unifying South Korea through surprise attacks, prompt responses, and combined nuclear and missile assaults remains unchanged. The central issue in this context revolves around determining the appropriate size of the Korean military's standing forces. This study employs the concept of net assessment as a novel method to ascertain the optimal size of the Korean military. Threats, strategic objectives, doctrine, and unit rotations are simultaneously considered from the enemy's perspective. In anticipation of security risks on the Korean Peninsula, an acceptable troop size will be proposed using the net assessment approach to calculate the appropriate standing force size.
        4,000원
        29.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : This study aims to understand the characteristics of accidents involving autonomous vehicles and derive the causes of accidents from road spatial information through autonomous vehicle accident reports. METHODS : For this study, autonomous vehicle accident reports collected and managed by the CA DMV were used as data sources. In addition, spatial characteristics and geometric data for accident locations were extracted by Google maps. Based on the collected data, the study conducted general statistics, text embedding, and cross-analysis to understand the overall characteristics of autonomous vehicle accidents and their relationship with road spatial features. RESULTS : The analysis results for characteristics of autonomous vehicle accidents, applying statistical analysis and text embedding techniques, reveal that the damages caused by autonomous vehicle accidents are often minor, and approximately half of the accidents are triggered by other vehicles. It is noteworthy that accidents where autonomous vehicles are at fault are not uncommon, and when the cause of the accident is within the autonomous vehicle, the accident risk can increase. The accident analysis results using spatial data showed that the severity of accidents increases when on-street parking is present, when dedicated lanes for bicycles and buses exist, and when bus stops are present. CONCLUSIONS : Through this study, geometric and spatial elements that appear to have an impact on autonomous driving systems have been identified. The findings of this study are expected to serve as foundational data for improving the safety of autonomous vehicle operations in the future.
        4,000원
        30.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, we examined the effects of gamma irradiation dosage on the mycelial growth of Auricularia auriculajudae and performed analyses of fruiting body yield, growth characteristics, taste, fragrance, and mineral composition. Assessments of mycelial growth in response to gamma irradiation at different intensities revealed an enhancement in the growth of fungi exposed to irradiation at 200 Gy. Fruiting body yield was also highest at 200 Gy, followed by 800 Gy and the control group. On the basis of these observations, we subsequently applied gamma ray doses of 200 and 800 Gy to examine the effects of irradiation on fungal quality characteristics. In terms of the taste of fruiting bodies, we detected no significant differences among the control, 200 Gy, and 800 Gy groups. Contrastingly, with respect to fragrance, we found that fungi treated with 200 Gy were characterized by a pattern that differed from those of the control and other treatment groups. Furthermore, whereas we detected no significant difference among treatments with respect total dietary fiber content, calcium content was found to be higher in the treatment groups compared with the control group, with the highest content being measured in fungi exposed to 800 Gy irradiation. Copper content was confirmed to be higher in the control group, whereas there were no significant differences between the fungi irradiated with 200 and 800 Gy. Contrastingly, the highest levels of zinc were detected in response to 200 Gy irradiation, followed by 800 Gy. Collectively, our findings thus indicate that gamma irradiation can contribute to promoting increases in the fruiting body yield and mineral contents of mushrooms.
        4,000원
        31.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Since maize (Zea mays L.) originated in central and south America, it requires warm climate conditions throughout its growing season. Growth halts when night-time temperatures drop below 10℃, and the plant may die if temperature reach -1.7℃. Thus, temperature should be maintained between 10 and 30℃ from seeding to maturity. The germination temperature for maize should be at least 8-11℃, whit an optimal range 32-34℃. Since temperature significantly affects the germination rate and period, it plays a crucial role in maize growth. In this study, we evaluated the quantity and feed value of 11 major varieties to determine those best suited for maize cultivation as feed in higher latitude, specifically in Democratic People’s of Republic of Korea, below 38 degrees north. A cultivation test was also conducted in Suwon in Republic of Korea, to assess adaptability in areas south of Mt. Suyang. Among the varieties tested, Shinhwangok2 reached silking the fastest, in 65 days, while Gwangpyeongok took the longest at 75 days. The stem length of all varieties exceeded 230 cm. Gwangpyeongok had the tallest stems, while Daanok and Shinhwangok2ho displayed the highest ear ratios. Dacheongok presented the highest values in both dry matter and TDN quantity, with 31,420 kg/ha and 21,66 kg/ha respectively. Pyeonggangok had the highest crude protein content at 8.0%. TDN (%) ranged from 57-68%, with Hwangdaok reaching up to 68%. Based on these findings, Dacheongok and Pyeonggangok appear to be the most suitable varieties for cultivation in terms of both quantity and feed value.
        4,000원
        32.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The study confirmed the "house search report(家宅搜索調書)" containing criminal records during the Japanese colonial period, as well as the production process and the way of expressing the illustrations contained in them. It also explored architectural values through analysis of the location and use of the building. This records the discovery of evidence by searching the residences of those involved in the crime from 1919 to 1922. The illustrations contained in this record were not standardized, so the contents of the article differed depending on the author's background and cultural experience. Nevertheless, this painting reflects the regional characteristics of traditional houses located throughout the Korean Peninsula. It is also evidence that the house was used for cultural, commercial, and industrial purposes, beyond the general assumption that it was used only for residential purposes. The "House Search Report(家宅搜索調書)" provides information on ordinary buildings that existed as the background of everyday life, rather than buildings with a specific purpose or exceptional design. It is evaluated as an important resource for understanding the diverse life and spatial structures of buildings during that time.
        4,800원
        33.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study is to estimate the future of second foreign language (hereafter, second FL) education after the high school credit system by understanding the primary/secondary teachers’ perceptions of second FL and the actual organization/operation status of second FL, and then to seek the proper tasks and solutions to expand students’ right to choose subjects, which is the purpose of this system. 324 primary/secondary school teachers participated in this study and the results are as follows. First, the languages the teachers preferred the most and would like to recommend to students were Chinese, other languages, French, and Japanese, in that order. Second, in the results of verifying the value of second FL education the primary/secondary teachers reported that overall they not only perceived the necessity of second FL education but also strongly agreed on the necessity to open various second FL subjects. Third, regarding the status of second FL subject, both Chinese and Japanese were overwhelmingly found in secondary school and a subject presented as a choice to students inquiring about their preferences and demands. This implies that the imbalance in second FL education originated not from students’ demand but from the imbalance of second foreign language teachers.
        6,000원
        36.
        2023.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study monitored the caffeine content of ready-to-drink coffee and verified the appropriateness of the labeling. The caffeine content was analyzed using HPLC. The average caffeine content of cold brew coffee was 0.31-1.04 mg/mL, with an average of 0.55 mg/mL. The average content of product was 147.27 mg/bottle, and taking into account the recommended daily intake, an adult can consume 2.7 bottles. Americano coffee was 0.15- 0.38 mg/mL, with an average of 0.28 mg/mL. The average content of product was 110.42 mg/bottle, and considering the recommended daily intake, an adult can consume 3.6 bottles. The caffeine content of decaffeinated cold brew coffee was 5.14 mg/bottle and compared to Americano coffee, more than 95% of the caffeine was removed. In addition, we verified the tolerance level of the total caffeine content in ready-to-drink coffee, and none of them exceeded 120%, signifying that all commercial products were effectively managed.
        4,000원
        37.
        2023.11 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to analyze microstructural changes and evaluate the mechanical properties of TWIP steel subjected to variations in heat treatment, in order to identify optimal process conditions for enhancing the performance of TWIP steel. For this purpose, a homogenization heat treatment was conducted at 1,200 °C for 2 h, followed by hot rolling at temperature exceeding 1,100 °C and cold rolling. Annealing heat treatment is achieved using a muffle furnace in the range of 600 °C to 1,000 °C. The microstructure characterization was performed with an optical microscope and X-ray diffraction. Mechanical properties are evaluated using micro Vickers hardness, tensile test, and ECO index (UTS × Elongation). The specimens annealed at 900 °C and 1,000 °C experienced a significant decrease in hardness and strength due to decarburization. Consequently, the decarburization phenomenon is closely related to the heat treatment process and mechanical properties of TWIP steel, and the effect of the microstructure change during annealing heat treatment.
        4,000원
        38.
        2023.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To investigate residual pesticide levels in agricultural products contained in Meal-kits, 27 Meal-kit products were collected from marts, Meal-kit shops, and online stores in Incheon City, South Korea. Seventy-six vegetable and thirty-seven mushroom products were analyzed for residual levels of 339 pesticides. Residual pesticides were detected in 23 out of 76 vegetables and were not present in the 37 mushroom products. The residual pesticide detection rate was 20.4% (23/ 113 cases). The pesticides famoxadone 0.034 mg/kg (standard: 0.01 mg/kg or less, PLS) and fenpyroximate 0.302 mg/kg (standard: 0.01 mg/kg or less, PLS) exceeded their maximum residue levels (MRL). This survey revealed that various types of pesticides remain in agricultural products in Meal-kits. Due to the nature of Meal-kit products, there is no separate standard for residual pesticides in agricultural products. Therefore, continuous monitoring of residual pesticides is necessary.
        4,000원
        39.
        2023.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        GC-MS/MS using liquid-liquid extraction (LLE) and C18 cartridges was used to identify and quantify levels of chlorpyrifos, chlorpyrifos-methyl, cypermethrin, deltamethrin and permethrin in bulk raw milk. A calibration curve spanning 10 ng/mL to 200 ng/mL was obtained with a satisfactory correlation coefficient of 0.99. The limits of detection (LOD) and limits of quantitation (LOQ) for chlorpyrifos, chlorpyrifos-methyl, cypermethrin, deltamethrin, and permethrin in the matrix ranged from 0.06 to 1.81 ng/mL and 0.19 to 6.04 ng/mL, respectively. The recoveries of 5 pesticides from spiked samples at 37.5-125 ng/mL ranged from 86.1 to 102.1%. The measurement of uncertainty of the GC-MS/MS method for these five pesticides was developed based on the analytical process and quantification. An analysis method that is easier and faster than the method specified in the Korean food standards codes for analyzing these five pesticides in raw material milk was developed. Moreover, the analytical method for chlorpyrifos, chlorpyrifos-methyl, cypermethrin, deltamethrin, and permethrin in bulk raw milk by GC-MS/MS was established.
        4,000원
        40.
        2023.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Purpose: The purposes of this study was to identify the nurses' experiences of prolonged mask wearing in the context of COVID-19. Methods: This study was a qualitative study that used the content analysis method. Data were collected using focus group interviews with 18 nurses at a tertiary general hospital from April 13 to 27, 2023. Results: Five themes and 15 sub-themes emerged through qualitative content analysis. The themes included: “Mandatory or optional experience of wearing a mask unrelated to COVID-19”, “Mandatory KF94 masks during the COVID-19 pandemic”, “Multifaceted changes in life due to mandatory mask wearing”, “Unexpected benefits of wearing a mask”, “Difficulties with wearing masks continue even after the COVID-19 pandemic”. Conclusion: This study confirmed the discomfort and difficulties of prolonged mask wearing among nurses in the context of COVID-19. Our findings suggest that there is a need for organizational and national support for nurses who are required to continue wearing masks after the COVID-19 pandemic.
        4,300원
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