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        검색결과 1,125

        42.
        2023.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The bandgap characteristics of semiconductor materials are an important factor when utilizing semiconductor materials for various applications. In this study, based on data provided by AFLOW (Automatic-FLOW for Materials Discovery), the bandgap of a semiconductor material was predicted using only the material’s compositional features. The compositional features were generated using the python module of ‘Pymatgen’ and ‘Matminer’. Pearson’s correlation coefficients (PCC) between the compositional features were calculated and those with a correlation coefficient value larger than 0.95 were removed in order to avoid overfitting. The bandgap prediction performance was compared using the metrics of R2 score and root-mean-squared error. By predicting the bandgap with randomforest and xgboost as representatives of the ensemble algorithm, it was found that xgboost gave better results after cross-validation and hyper-parameter tuning. To investigate the effect of compositional feature selection on the bandgap prediction of the machine learning model, the prediction performance was studied according to the number of features based on feature importance methods. It was found that there were no significant changes in prediction performance beyond the appropriate feature. Furthermore, artificial neural networks were employed to compare the prediction performance by adjusting the number of features guided by the PCC values, resulting in the best R2 score of 0.811. By comparing and analyzing the bandgap distribution and prediction performance according to the material group containing specific elements (F, N, Yb, Eu, Zn, B, Si, Ge, Fe Al), various information for material design was obtained.
        4,200원
        48.
        2023.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 노인의 야외활동 증진을 위해 고령화가 심각한 중국 산둥성 쯔보시의 도시공원을 대 상지로 노인활동에 적합한 식재경관 조성지표를 탐색·도출하는데 목적이 있다. 객관적이고 적 합한 지표를 설정하기 위해 문헌 고찰, 현장 설문조사, 현장조사를 통해 노인들의 생리적·심리 적 특징, 노인들의 공원 이용특징과 식재경관 의식, 노인 활동공간 내 식재의 의한 공간구성 특 징과 주요 식재수종 및 선호 경관 등을 파악하고 이에 따른 도시공원 노인활동에 적합한 식재경 관을 파악하였다. 그리고 조경식물과 이들 집합체인 식재경관의 기능과 관련된 선행연구를 토 대로 41개 식재경관 지표 후보군을 도출하였다. 적합한 식재경관 조성지표를 선정하기 위하여 전문가 조사를 3회 실시하였다. 조사분석 결과, 전문가의 의견을 근거하여 치유식물과 방향성 식물, 계절에 따라 변화하는 식물의 배치와 사계절 경관, 새를 유인하는 식물과 관과식물 비율, 산소 방출량이 높은 식물과 식물의 공기정화는 통합되었고 교목의 단식을 추가하였다. 중요도 평균값, 내용 타당도, 수렴도, 합의도 등의 분석결과, 방충식물, 식물의 표지기능 등 2개 지표가 중요도 평균값 낮으므로 제외되었다. 식물의 방풍·통풍성, 친근한 식물, 흥미로운 식재, 상록식 물과 낙엽식물의 비율 등 4개 지표가 기준에 부합하지 않아 제거되었다. 최종적으로 조경식물과 이들 집합체인 식재경관의 기능이 표현된 식재경관 조성지표 32개가 선정되었으며, 노인들의 야외활동 증진을 위한 공원설계 및 관리에 필요한 정보와 자료를 제공하는데 연구의의가 있다.
        4,500원
        49.
        2023.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 소나무재선충의 매개충인 솔수염하늘소와 북방수염하늘소에 대하여 무인항공기 (무인헬리콥터)를 이용하여 스피네토람의 약효 및 약해를 조사하였다. 하늘소를 대상으로 등록된 펜토에이트 유제, 비펜트린 액상수화제, 하늘소를 제외한 딱정벌레가 대상인 에토펜프록 스 유제, 디플루벤주론 수화제와 나방류에 방제 약제로 등록된 인독사카브 수화제, 스피네토람 액상수화제 6종을 ULV기로 살포하여 솔수염하 늘소에 대한 섭식독과 접촉독을 확인한 후 선발하였다. ULV 시험 결과, 펜토에이트, 비펜트린, 인독사카브, 스피네토람의 33배, 55배 희석배수 액은 처리후 3일차에 접촉독과 섭식독에서 100% 살충율을 보였으나, 에토펜프록스는 7일차 접촉독 살충율 88.9%(33배), 88.9%(50배), 섭식독 살충율 93.4%(33배, 50배), 디플루벤주론은 7일차 접촉독 살충율 83.3%(33배), 섭식독 80.3%, 53.9%(50배)로 조금 낮은 살충률을 보였다. ULV 시험에서 선발된 가장 적합한 스피네토람의 33배액을 무인항공기로 살포하여 솔수염하늘소와 북방수염하늘소에 대한 감수성을 평가한 결 과, 98.6% - 100%의 살충율을 보였다. 그러나, 해당 약제의 매개충 방제에 적용하기 전에 항공 살포에 의한 꿀벌에 대한 위해성 평가가 필요할 것 으로 판단되었다.
        4,000원
        50.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study carried out from March 2021 to October 2021 in the upper part (St. 1) and middle part (St. 2) section of Yongsu stream, a branch of the Geum river, using PIT telemetry to understand the movement patterns and habitat characteristics of Odontobutis interrupta, a Korean endemic species. O. interrupta collection was used kick net (5×5 mm) and fish trap (5×5 mm). After collecting fish, PIT tag insertion was performed immediately in the site. Reader (HPR Plus Reader, biomark, USA) and portable Antenna (BP Plus Portable Antenna, biomark, USA) were used for detection of fish to monitoring the tagged O. interrupta. As a result of PIT telemetry applied to 70 individuals, mean movement distance was 36.5 (SE, ±6.6) m. There was a significant difference between total length and movement distance (P≤0.05). O. interrupta was mainly identified in average water depth, 36.2±1.9 cm, average water velocity, 0.03±0.07 m s-1 and average distance from watershed, 4.4±0.3 m. Extent of rock used for habitat was varied from 32 to 4,000 cm2. There was no statistical difference between the area of the first selected rock and the area of the after selected rock (P>0.05). but there was significant difference between total length and the area of the rock except for detection before 24 hours (P<0.01). Therefore, to restore the habitat, it is considered necessary to create various substrate structures by providing various habitat environments (water depth, flow rate, stone, etc.) for each individual size.
        4,200원
        51.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Pleurotus species are the most consumed and cultivated mushrooms in Korea. Although oyster mushrooms (P. ostreatus) can be cultivated automatically, their storability is slightly lower than that of king oyster mushrooms (P. eryngii) and winter mushrooms (Flammulina velutipes); therefore, the export proportion of oyster mushrooms is very low. Since Korean mushrooms are highly preferred across Southeast Asian, the export of oyster mushrooms in the form of complete substrates is expected to be more promising than that of fresh mushroom. Here, 1 and 2.5 kg complete substrates of P. ostreatus ‘Soltari’ and P. sajor-caju ‘Sambok’ were prepared and stored at different temperature from 0 to 15°C for 10 days. Thereafter, the formation of fruiting bodies was induced. Since the 2.5 kg complete substrates required 70 days of incubation, their mycelia were at an advanced age and their fruiting bodies did not grown normally. When 70%-incubated complete substrates were stored at 5–10°C, the growth was faster and more uniform and stable fruiting bodies were formed. Export test of complete substrates to Vietnam using distribution containers set at 0°C and 15°C revealed that the growth period was shortened by 1–2 days when the distribution containers were set at 15°C and the yield of ‘Soltari’ increased by approximately 10%. In addition, even though the yield of ‘Sambok’ was similar between treatments at 0°C and 15°C, the quality of fruiting bodies from 15°C-distributed complete substrates was much better than that of those from 0°C-distributed substrates.
        4,000원
        52.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : The purpose of this study was to select recurring congested sections through an objective and reasonable method using intelligent transportation system (ITS) collection data as the first phase for controlling recurring congested sections. The selection is meant to enhance the utilization of national highway ITS collection data that are just managed as statistical data focusing on real-time traffic information or not satisfactorily used. METHODS : Hourly statistical data were obtained using travel speed with a 5-min frequency per information-providing section stored in the database server. The travel speed data were collected from field equipment in general national highway sections (793.8 km in 380 sections of 16 lines in 2017) in the Seoul Metropolitan Area through a literature review of congestion standards. Subsequently, the congested sections were drawn by dividing a month into weekdays and weekends, and the status of the monthly change and characteristics of the congested sections were analyzed. Based on the monthly data on the congested sections, monthly mean congested days and hours were calculated to select the significant recurring congested sections in 2017 and applied to the congestion frequency standard. RESULTS : Recurring congested sections occurred in seven sections (33.9 km) in three lines — in five sections (24.8 km) of two lines during the weekdays and in two sections (9.1 km) of one line during the weekends. The recurring congested sections selected based on the congested days and the recurring congested sections selected based on the congested hours were found to be the same. The recurring congested sections during the weekdays and weekends were not mutually duplicated and were divided. More congestion occurred during the weekdays than on weekends. CONCLUSIONS : In the seven sections selected as recurring congested sections, congestion occurred for more than six months during one year, indicating that congestion is concentrated in specific months, albeit continuously and repeatedly occurring over the long term. The recurring congestion section selection standard and method used in this study are considered to be objective and reasonable. If recurring congested sections are selected using the standard and method presented in this study using ITS collection data targeting general national highways nationwide in the Seoul Metropolitan Area, it is necessary to determine whether the standard and method reflect actual congestion situations satisfactorily. According to the result, a further study considering congestion speed and congestion frequency standards is needed.
        4,000원
        55.
        2022.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        밭농업의 일관화를 위해 개발된 복합작업기의 효율적인 운영전략은 연료절감의 목표와 함께 저속 로터리작업의 품질에도 중점을 두어야 한다. 본 연구는 둥근 두둑 복합작업기의 작업품질을 유지하는 적정조건에서 동력과 연료소비를 계상하고 비교하여 집약적 밭농업에서의 효율적인 작업기 운용전략을 제안하려 하였다. PTO 표준 시험성적을 이용한 Kim 모델은 임의의 부분 부하 상태에서 연료소비량(FC), 비체적 연료소비율(SVFC) 및 단위면적당 연료소비율(FCA)를 구하고 셀선도(shell diagram)를 얻을 수 있다. 따라서 개발된 복합작업기에 적용할 카테고리 1 트랙터(DK450)와 카테고리 2 트랙터(PX800)를 선정하고 적정운용 조건에서의 연료소비 특성을 비교하였다. 이전 연구를 바탕으로 이론적인 목표 작업속도는 3.0<SPDth<4.0km/h와 로터리 피치(p)가 35<p<47cm/rev인 범위를 적정한 작업 기준(criteria)으로 하여 운용조건을 선택하였다. 각 트랙터에서 적정한 운용조건의 사례들을 비교하면 작은 트랙터(DK 450)를 사용함으로써 얻을 수 있는 연료소비 절약율은 FC가 19.4%, SVFC가 21.1% 그리고 FCA가 29.9% 정도로 평가된다.
        4,300원
        56.
        2022.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구의 목적은 국내 발레단 소속 여자 무용수를 대상으로 연속 회전점프 시 시각선택과 회전 순서에 따른 차이를 도약과 착지구간으로 분류하여 비교하였다. 10명의 대상자(연령: 26.0±2.9 yrs, 신장: 163.4±3.3 cm, 체중: 46.8±3.6 kg, 발레경력: 12.3±5.9 yrs)가 연구에 참여하였다. 3차원 동작분석기와 지면반력기를 이용하여 신체중심의 높이와 도약과 착지 시 지면반력을 측정하였다. 시각선택(양눈 사용, 왼 눈 사용, 오른눈 사용)과 회전순서(첫번째 회전점프, 두 번째 회전점프)에 따른 차이를 반복측정 이원변량 분석을 통하여 분석하였다. 신체중심의 높이는 첫 번째 회전점프가 높게 나타났다. 도약 시 지면반력의 좌 우힘은 좌우발 모두 두 번째 회전점프에서 왼발은 외측힘, 오른발은 내측힘이 강하게 나타났고, 전후힘은 오른발에서 첫 번째 회전점프 시 전방힘이 강하게 나타났으며, 수직힘은 좌우발 모두 차이가 없었다. 착지 시 전후힘은 왼발에서 두 번째 착지에서 후방힘이 강하게 나타났고, 오른발은 왼쪽 시각 사용에서 후방힘 이 강하게 나타났다. 수직힘은 왼발에서 두 번째 착지, 오른발은 첫 번째 착지에서 강하게 나타났다.
        4,000원
        57.
        2022.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study evaluated the quality of school milk programs and analyzed the relative importance of school milk program selection attributes using conjoint analysis. The survey was conducted on students from middle and high schools in metropolitan cities that provide school milk programs. Responses were received from 414 students and the data was subjected to frequency analysis, t-test, and conjoint analysis using the SPSS Statistics Package. While evaluating white milk in the school milk program, middle school students rated ‘packaging condition’ (4.23) the highest, high school students rated ‘nutrition’ (4.64) the highest, and their evaluation of all the quality attributes was significantly different from that of middle school students (p<0.001). Overall satisfaction scores too, showed a significant difference between high school (4.46) and middle school students (4.01) (p<0.001). Processed milk & dairy products had the highest satisfaction score in the attribute of ‘serving time’ (4.57). The relative importance of the choice attributes of the school milk program was in the order of ‘number per item’ (62.260%), ‘temperature’ (25.708%), and ‘serving method’ (12.032%) for all students. The school milk program most preferred by all students and middle school students was to provide milk at a refrigerated temperature, select white milk three times a week, processed milk, fermented milk, and cheese twice a week, and provide it at the desired time.
        4,000원
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