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        검색결과 1,373

        1.
        2024.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study explored the changes in senescence patterns and vase life of cut roses grown in summer and autumn, aiming to identify the relationship between harvest seasons and flower longevity. We analyzed gene expression profiles associated with lignin, pectin, ethylene, auxin, and sucrose transport to understand the molecular mechanisms underlying senescence symptoms, such as the bent neck, petal abscission, and petal wilting in cut rose flowers. Our results revealed season-dependent occurrences of bent neck and petal abscission, with higher incidence rates in autumn-harvested rose flowers. These increases in bent neck and petal abscission contributed to a shortened vase life for the cut flowers. Gene expression analysis indicated that elevated levels of ethylene biosynthesis genes and reduced expression of lignin, pectin biosynthesis, auxin response factor, and sucrose transport genes accelerated the increased senescence symptoms. Notably, the incidence rates of the bent neck were highly negatively correlated with the transcript levels of key genes involved in lignin and pectin biosynthesis, RhPRXPX and RhGAUT1, in pedicels. These findings contribute to our understanding of the molecular factors influencing the mechanical strength of flower pedicels and provide insights for postharvest strategies to enhance the ornamental value of cut flowers across seasons.
        4,500원
        2.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        자기공명(magnetic resonance, MR)영상에서 주로 발생하는 Rician 노이즈는 영상의 화질을 저하하는 주요 요소 중의 하나이다. 본 연구에서는 노이즈 제거에 효율적이라고 잘 알려진 총변이(total variation, TV) 알고리즘을 모 델링하여 Rician 노이즈 레벨에 따른 파라미터를 최적화하고자 한다. 시스템은 8채널 기반의 3.0 T 장치를 활용하였 고 물 팬텀 영상을 획득하여 각각 Rician 노이즈를 0.05, 0.10, 0.15, 그리고 0.20 값을 부가하였다. TV 알고리즘 은 Rudin-Osher-Fatemi 모델을 기반으로 모델링하였고 최적화를 수행하기 위하여 반복수 파라미터를 조정하여 획득된 영상에 적용하였다. 결과적으로 Rician 노이즈 레벨을 0.05, 0.10, 0.15, 그리고 0.20을 사용하였을 때 각 각 30, 40, 80, 그리고 120 반복수를 기반으로 한 TV 노이즈 알고리즘에서 가장 우수한 신호 대 잡음비(signal to noise ratio, SNR)와 대조도 대 잡음비(contrast to noise ratio, CNR) 결괏값이 도출되었다. 또한, 최적화된 반복수를 적용한 TV 알고리즘을 사용한 MR 영상에서 기존의 위너 및 중간값 필터를 사용하였을 때 비하여 SNR과 CNR 모두 우수한 값을 획득할 수 있었다. 특히 기본적으로 획득된 MR 영상보다 최적화된 TV 알고리즘을 적용한 영상의 평균 SNR과 CNR은 각각 3.11 및 3.31배 향상됨이 증명되었다. 결론적으로, 노이즈 제거 효율이 우수한 TV 알고리즘의 최적화된 파라미터를 활용한다면 MR 영상에서의 활용 가능성이 클 것으로 기대한다.
        4,000원
        3.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Air blower has been widely used in many industrial fields such as wind tunnel and large ventilation systems. Its performance is affected by operating conditions and system geometry of inpeller and duct, and these design parameter optimization is essential for the effective development. CFD analysis is carried out to investigate the air flow field characteristics with outlet total pressure in a blower system. Intake air into the impeller blade through the inlet is compressed, and then gradually discharged from the outlet with ascending total pressure, and predicted results are compared with test data. Especially this overall pressure difference in the blower system severely depends on the flow rate. These results are expected to be used as applicable design data for blower performance improvement.
        4,000원
        4.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, we analyzed how the revenue water ratio(RWR) is affected by changes in conditions of the water supply area, such as the ratio of aging pipes, maintenance conditions, and revenue water. As a result of analyzing the impact of pipe aging and maintenance conditions on the RWR, it was confirmed that the RWR could be decreased if the pipe replacement project to improve the aging pipe ratio was not carried out and proper maintenance costs were not secured. It was also confirmed that an increase in the revenue water could be operated to facilitate the achievement of the project’s target RWR. In contrast, a decrease in the revenue water due to a population reduction could affect the failure of the target RWR. In addition to analyzing the causes of variation in the RWR, the calculation of estimated project costs was considered by using leakage reduction instead of RWR from recent RWR improvement project cost data. From this analysis, it was reviewed whether the project costs planned to achieve the target RWR of the RWR improvement project in A city were appropriate. In conclusion, the RWR could be affected by variations in the ratio of aging pipes, maintenance conditions, and revenue water, and it was reasonable to consider not only the construction input but also the input related to RWR improvement, such as leakage reduction, when calculating the project cost.
        4,800원
        6.
        2023.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In the last five decades, there has been a consistent decline in the total catch of fisheries in the Korean jurisdiction since the peak in 1986. The decline in catch slowed and slightly rebounded in the 2000s, but changed back to a decline in the 2010s. As indicators that can identify changes in the marine ecosystem, trophic level (TL), biodiversity index (H'), and the ratio between pelagic fish and demersal fish (P/D) were analyzed by each local marine ecosystem. There were some different changes in each local marine ecosystem, but the mean TL and H' decreased and P/D increased in general in Korean waters. Demersal fish, which were dominant in the 1970s and 1980s, declined, and small pelagic fish and cephalopods have dominantly changed since the 1990s. However, these changes are not simple, and they are fluctuating in complex ways relating to each marine ecosystem and the timing. It is believed that changes in marine ecosystems in Korean waters are likely caused by a combination of fisheries and climate change. The ecosystem indicators reflected a change in the total catch, a sharp drop in catch of demersal fish, and increasing catch of pelagic fish since the mid-1980s.
        4,500원
        10.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 부산신항에서 스크러버를 장착한 선박이 세정수를 배출하였을 때 인근 해역에 미치는 영향을 검토하기 위해 확산예측을 수행하였다. 세정수에 포함된 용존무기탄소(DIC)의 농도를 통제한 채로 세정수의 pH 조건별로 해역에 미치는 영향을 대조기 와 소조기로 나누어 평가하였다. 선박 1대에서 24시간 동안 세정수를 배출할 때, pH가 최대 0.076, 0.083 감소하였다. DIC의 경우 0.561mg/L, 0.612mg/L 증가하였다. 부산신항에 수용가능한 선박수인 24대를 전부 가정하여 실험하였을 경우 pH는 0.200, 0.545 감소하였고, DIC는 1.464mg/L, 3.629mg/L 증가하였다. 일반적으로 스크러버가 세정수를 처리하였을 때 pH 6.1인 것을 감안하여 선박 1대에서 pH 6.1인 조건으 로 24시간 동안 세정수를 배출하는 경우 우리나라 연근해의 연간 pH 변화량보다 약 33.7배 더 큰 폭으로 감소하는 것으로 계산되었다. 선 박이 24대일 경우에는 하루이상 표층의 성층화를 유발하고 수심 4m까지 영향을 주는 것으로 예측되었다.
        4,000원
        11.
        2023.10 구독 인증기관·개인회원 무료
        최근 주요 절화 수입량이 증가하면서 외래 병해충 유입률 또한 증가하고 있다. 농림축산검역본부 병해충정보 시스템(PIS)에 따르면 최근 10년간(2011-2020년) 수입된 절화류에서 검출된 총채벌레목은 총 43종 6,734건이다. 그중 가장 많이 검출된 총채벌레는 Frankliniella occidentalis (2,526건), Thrips tabaci (1,470건)로 전체 검출건수의 59% 이상 차지한다. 본 연구에서는 수입 절화류에서 검출률이 가장 높은 총채벌레 두 종의 미토콘드리아 DNA CO I 유전자를 이용하여 염기변이에 의한 국가별 다양성과 유전적 다양도 분석을 실시하였다. 네덜란드, 중국 등 7개국에서 검출한 Frankliniella occidentalis 184개 개체에서 9가지의 단상형(haplotype)이 관찰되었다. 또한 페루, 네덜란드 등 6개 국가에서 검출된 Thrips tabaci 80개 개체에서는 7가지 단상형이 보였다. 본 연구에서 검출 한 mtDNA내 염기서열 다형성은 총채벌레 집단의 국가적 변이성 추정 및 연관성 분석에 기초자료로 활용할 것으 로 기대한다.
        12.
        2023.10 구독 인증기관·개인회원 무료
        Palaclemensia is a genus within the family Incurvariidae, and it has been reported to be a monophagous or narrow oligophagous genus, like other incurvariids, except for two polyphagous species, Paraclemensia incerta and P. acerifoliella. Paraclemensia incerta is one of the common species in Japan and Korea, and seven host plant families are recognized. However, these host records aren’t based on DNA analysis or detailed morphological comparison. Therefore, it was hypothesized that there is genetic differentiation among host races in P. incerta. To investigate this hypothesis, DNA analysis and morphological comparison were performed on Paraclemensia species collected from Japan. As a result, genetic divergence among populations feeding different host plants was not confirmed. Moreover, not only P. incerta but also P. caerulea were suggested to be polyphagous. In contrast, geographic genetic divergence in P. incerta and P. caerulea was observed in Japan. Additionally, it is suggested that P. viridis, P. oligospina, and P. cyanea, despite external morphological differences, could be the same species.
        13.
        2023.10 구독 인증기관·개인회원 무료
        Riptortus pedestris has established symbiotic interactions with specific bacteria from soil environment in every generations. The soil environment is extremely heterogeneous with microbial diversity, suggesting that bacterial composition of the R. pedestris can be affected by surrounding environments. Therefore, we investigated spatiotemporal variation of bacterial communities in wild R. pedestris collected from five mainland areas and Jeju Island in South Korea across insect generations. Among the 390 R. pedestris adults collected, we detected a total of 28 bacterial genera from the symbiotic region of insects. Among the bacterial genera, genus Caballeronia bacteria was the most abundantly detected regardless of sampling site and generation. Nevertheless, bacterial richness varied among the insect generations with 10 genera detected in overwintered generation, 15 genera in the 1st generation and 18 genera in the 2nd generation. Moreover, we found five bacterial genera that were exclusively detected from the Jeju island compared to the mainland areas surveyed.
        14.
        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
        15.
        2023.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The coda /s/ is the most extensively studied phonological segment in Hispanic dialectology and sociolinguistics. However, the coda /s/ in Peruvian Andean Spanish has received relatively little attention. This study examines the variation in syllables and word-final /s/ in the city of Cusco, Peru. The statistical analysis of 2400 tokens from 24 sociolinguistic interviews reveals that the Spanish of Cusco is located within the conservative dialects with the predominant use of the sibilant [s] and that coda /s/ weakening is conditioned by linguistic factors, such as word position and the following phonological context. Additionally, younger speakers and those who have higher levels of education weaken codal /s/ more frequently than older generations and speakers with lower levels of education.
        6,600원
        16.
        2023.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In a self-level riser, the piston rod generates hydraulic pressure while reciprocating along the pump rod, so components such as rods and valves require precise processing technology. Among them, the design of the pump rod was changed to a spiral groove method because there was a risk of poor operation during eccentricity. In this paper, the design and 3D modeling of the pump rod were conducted, and the structural stability of the core part according to the load change applied to the pump rod was confirmed.
        4,000원
        17.
        2023.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The change in the performance of the range hood according to the pressure change was investigated through a comparative experiment, and the conclusion is as follows. KS C 9304: In 2020, static pressure was applied at 100 Pa according to the fan standard, and the test was conducted by varying the outlet diameter and power consumption. In the case of Motor power 55W, the air volume value was 184.6 when the outlet diameter was 125mm. As a result of the test, if the power consumption is 52.0W, the diameter of the outlet is 125mm, and the power consumption is 60.8W, and the diameter of the outlet is 100mm, it meets 160 or more and less than 200 (constant pressure 100Pa).
        4,000원
        18.
        2023.07 구독 인증기관·개인회원 무료
        Improvisation is an important firm competence in product innovation as firms increasingly face inherent uncertainty in new product development (NPD) process and frequent jolts in the external environment. While there is some empirical and conceptual work on the value of improvisation for several new product outcomes, there is lack of empirical research on the antecedents of improvisation in innovation studies. We attempt to address this gap by studying the role of team variation and team convergence traits in the occurrence of improvisation in a sample of 118 NPD teams from manufacturing firms.
        19.
        2023.07 KCI 등재 구독 인증기관 무료, 개인회원 유료
        An elastic bearing must be strong against vertical loads and flexible against horizontal loads. However, due to the material characteristics of rubber, it may show variability due to the manufacturing process and environmental factors. If the value applied in the bridge design stage and the actual measured value have different values or if the performance during operation changes, the performance required in the design stage may not be achieved. In this paper, the seismic response of bridges was compared and analyzed by assuming a case where quality deviation occurs during construction compared to the design value for elastic bearings, which have not only always served as traditional bearings but also have had many applications in recent seismic reinforcement. The bearing's vertical stiffness and shear stiffness deviation were considered separately for the quality deviation. In order to investigate the seismic response, a time history analysis was performed using artificial seismic waves. The results confirmed that the change in the bearing's shear stiffness affects the natural period and response of the structure.
        4,000원
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