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        검색결과 2,568

        61.
        2024.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Air flow field characteristics in a compact chamber system are indispensable for the efficient development of vehicle aerodynamic performance. In this study, air flow and velocity uniformity in the chamber system were numerically analyzed using the CFD method. Air flows at a uniform velocity from the outlet of the blower, passes fast through the heat exchanger with partial pressure difference, and then moves into the blower inlet. Overall pressure drop through the fan gradually increases with the flow rate. The uniformity varies along the test section, decreasing by 5-10% with distance from the nozzle. These predicted results can be widely used as basic conceptual design data for an efficient vehicle chamber system.
        4,000원
        62.
        2024.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        황근은 동아시아에서 가장 북쪽에 분포하는 준맹그로브에 속한다. 황근의 식생 분포 변화를 살펴보는 것은 기후변화 로 인한 우리나라의 난대 식생대 변화를 관찰하는데 유용할 것으로 판단된다. 본 연구는 Hibiscus속 준맹그로브와 황근의 지리적 분포 관계를 살펴보고 황근 군락 분포에 영향을 미치는 환경요인을 분석하였다. 황근 군락은 지역과 해안 유형에 의해 구분할 수 있었는데, 그룹 Ⅰ의 경우 깊은 만 안쪽으로 함몰된 지형에 발달한 토양을 기반으로 군락이 형성되어 있으며 초본 염생식물과 함께 출현하였다. 그룹 Ⅱ는 기반암이 많이 노출된 해안 혹은 자갈 해안에서 강한 파도의 영향을 견딜 수 있는 덩굴성 해안 관목과 함께 발달하였다. 그룹 Ⅲ은 일본에 위치한 군락으로 우리나라보 다 다양한 해안 유형에서 나타나며, 100개체 이상 큰 규모의 순군락이 출현하였다. 황근 군락 분포에 영향을 주는 환경요인을 분석한 결과 가장 따뜻한 분기의 강수량이 가장 중요한 요인으로 분석되었다. 본 연구에서는 기후 인자들과 준맹그로브 분포의 관계를 분석하고 기후변화 영향에 대한 황근의 생태적인 반응을 이해하는 기반을 마련하고자 한다.
        4,500원
        63.
        2024.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 생태계교란생물로 지정된 네 종의 외래 거북(붉은귀거북 속, 리버쿠터, 중국줄무늬목거북, 플로리다붉은배거북) 에 대한 잠재서식지 분포를 분석하였다. 잠재서식지 예측에는 지형, 기후, 토지피복, 인간의 영향 등 16개의 환경변수와 MaxEnt 머신러닝 모델을 이용하였다. 연구 결과는 출현 빈도가 높은 지역이 모든 종에서 유사하다는 것을 보여주었다. 외래 거북의 서식지는 도시화 및 인간의 접근성이 용이한 지역과 연관성이 높았다. 반면, 강수량과 기온과 같은 자연적 요인의 영향은 상대적 으로 낮게 나타났다. 잠재서식지 분석 결과는 AUC 값이 0.913으로 높은 모의 효율을 보여주었다. 이는 외래 거북의 확산을 효과적으로 관리하기 위해서 주요 도로 주변을 포함한 도심 및 도시 주변 지역에 대한 모니터링과 관리가 중요함을 시사한다. 이 연구는 외래종으로 인한 생태계 영향을 완화하기 위한 전략 수립에 중요한 기초 자료를 제공한다.
        4,800원
        65.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Distribution and logistics industries contribute some of the biggest GDP(gross domestic product) in South Korea and the number of related companies are quarter of the total number of industries in the country. The number of retail tech companies are quickly increased due to the acceleration of the online and untact shopping trend. Furthermore, major distribution and logistics companies try to achieve integrated data management with the fulfillment process. In contrast, small and medium distribution companies still lack of the capacity and ability to develop digital innovation and smartization. Therefore, in this paper, a deep learning-based demand forecasting & recommendation model is proposed to improve business competitiveness. The proposed model is developed based on real sales transaction data to predict future demand for each product. The proposed model consists of six deep learning models, which are MLP(multi-layers perception), CNN(convolution neural network), RNN(recurrent neural network), LSTM(long short term memory), Conv1D-BiLSTM(convolution-long short term memory) for demand forecasting and collaborative filtering for the recommendation. Each model provides the best prediction result for each product and recommendation model can recommend best sales product among companies own sales list as well as competitor’s item list. The proposed demand forecasting model is expected to improve the competitiveness of the small and medium-sized distribution and logistics industry.
        4,500원
        66.
        2024.06 구독 인증기관 무료, 개인회원 유료
        The issue of marine accidents can be based on the traffic/distribution of vessels in the waterways. These accidents are often associated with human and financial losses and require special attention. Usually, these accidents include collision of two fishing vessels with each other, collision of a fishing vessel with other types of vessels in the course and collision of a fishing vessel with an obstacle in the course (Yancai, et al, 2020). In this article, we first want to deal with analysing the recorded statistical samples in 7 fishing areas in coastal waters of South Korea in 2023, while fuzzy clustering them. Then, according to analysing the sample data and finding the probabilistic structure and the membership of data sets the determined clusters, through Monte Carlo simulation, we will generate similar data in each of the 7 studied regions and model them in unsupervised mode. The generated data by Monte Carlo simulation based on the statistical distribution will able us to study the reality of distribution and possible accident in our target areas and find the model for future demands. We show that how the simulated data reduce the cost of data analysis and deliver us the facts of clusters for fishing vessels collisions. Finally, we reach to the most notified area for preventing the fishing vessels accidents and to make more preparations for reducing the human and costly damages in future activities.
        4,000원
        67.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        수생식물은 지각류의 종다양성과 풍부도를 결정하는 중요한 요인이지만, 식물의 종구성이나 구조에 대한 지각류의 영향은 충분하게 고려되지 않았다. 남한은 수생식물이 피복되기 쉬운 습지나 저수지가 전국에 산재하고 있기 때문에 지각류를 포함한 생물 연구 시 수생식물에 대한 고려가 필요하다. 본 연구에서는 6가지 유형의 미소서식처에서 지각류 군집의 종수와 풍부도를 조사하고, 이 결과를 기반으로 서식처 보전과 효율적인 관리에 대해 고찰하고 한다. 지각류 군집의 높은 종수와 풍부도는 부유식물, 부엽식물, 그리고 침수식물이 함께 구성된 혼합된 식물 군락에서 목격되었다. 식물 군락에서 침수식물의 포함은 서식처 구조의 복잡성에 크게 기여하며, 지각류 군집의 종수와 풍부도를 증가시킬 수 있다. 이는 침수식물이 부재한 부유 및 부엽식물로만 구성된 식물 군락과 비교함으로서 침수식물의 효율성을 파악할 수 있다. 혼합된 식물 군락에서는 다른 식물 군락에 부재하는 지각류 종 (Graptoleveris testudinaria, Ilyocryptus spinifer, Leydigia acanthocercoides)이 출현함으로서 종다양성이 가장 높았다. 혼합된 식물 군락에서 침수식물의 점차 적인 생물량 (g) 증가는 지각류 군집의 종수와 풍부도를 유의하게 증가시켰다 (p<0.05). 이는 혼합된 식물 군락에서 침수식물의 증가가 지각류의 서식처로서 효율성에 긍정적인 영향을 미친다는 강력한 증거이다. 비록 침수식물은 수중에 침수되어 서식하기 때문에 경관적/미적인 가치에 크게 기여하지 않지만, 생물학적 측면에서 종다양성을 증가시키는 효과를 가지기 때문에 습지 창출/복원 시 중요하게 고려되어야 할 것으로 판단된다.
        4,600원
        68.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study presents a fine scale distribution of the endangered species, Odontobutis obscura, through field surveys and literature reviews. Using the mark-recapture method, the population size in major habitats was determined. Field surveys conducted on 18 streams in Geoje Island revealed that the O. obscura was only found in the main streams and tributaries of the Sanyang, Gucheon, and Buchun Streams, which are part of the Sanyang Stream watershed. The O. obscura exhibited relative abundances ranging from 0.5% to 35.3% at different locations, with certain spots showing higher relative abundances (18.8% to 35.3%), indicating major habitat areas. A review of six literature studies confirmed the presence of the O. obscura, although there were differences in occurrence status depending on the purpose, scope, and duration of the studies. Combining the results of field and literature surveys, it was found that the O. obscura inhabits the main and tributary streams of the Sanyang, Gucheon, and Buchun Streams, from the upper to lower reaches. Currently, the O. obscura population in the Sanyang Stream watershed maintains a stable habitat, but its limited distribution range suggests potential issues such as genetic diversity deficiency in the long term. The population size of the O. obscura was confirmed at two specific locations, with densities of 0.5 to 1.5 individuals per m2. The average movement distance from the release point was 13.1 m, indicating the limited mobility characteristic of ambush predators. Understanding the distribution and population size of endangered species is the first step towards their conservation and protection. Based on this information, further research could significantly contribute to the conservation of the O. obscura.
        4,000원
        69.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Current distribution of Korean Cottus pollux was investigated by conducting field surveys and environmental DNA analysis in September to November 2022 and March to May 2023. As a result of the field survey, the presence of C. pollux was confirmed in the uppermost stream of Hyeongsangang River, as well as in Deokdongcheon, Jeolgolcheon, and Hoamcheon Streams. The main habitat of C. pollux was the riffle area in the upper reaches of streams with clean water and boulder-cobble bottoms. As a result of environmental DNA analysis, the samples determined to be positive included all streams in which the presence of C. pollux was confirmed in the field survey. In addition, Namcheon and Singwangcheon Streams were determined to be positive, indicating potential as its habitats. Since C. pollux has a narrow distribution area and a small population size, continuous monitoring and conservation measures are required to immediately respond to damage caused by typhoons and river works, which are the main causes of habitat disturbance, in order to maintain a stable population.
        4,000원
        70.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, the effect of Distribution efficiency through the fishery production base distribution center (FPC) on the production site board facility was studied. FPC is a new distribution system for Korean fishery products that has been promoted in earnest since 2012, and in this study, the effect before and after the introduction of FPC was analyzed using the DID (Difference in Difference) model for the effect of FPC in the fishery industry. The results of analysis shows that in the case of Wando Geumil FPC, the volume and unit price of consignment sales decreased during the analysis period, which was statistically significant. In the case of Sokcho FPC, the volume of consignment sales decreased during the analysis period, which was statistically insignificant. But the unit price of consignment sales rose during the analysis period, which was statistically significant. In the case of Gyeongju FPC, the volume of consignment sales increased during the analysis period, which was statistically significant at the 90% confidence level. But the unit price of consignment sales fell during the analysis period, which was statistically significant.
        5,700원
        73.
        2024.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Single-leg squat (SLS)s are commonly used as assessment tool and closed kinetic exercises are useful for assessing performance of the lower extremities. Pronated feet are associated with foot pressure distribution (FPD) during daily activities. Objects: To compare the FPD during SLSs between groups with pronated and normal feet. Methods: This cross-sectional study included 30 participants (15 each in the pronated foot and control groups) are recruited in this study. The foot posture index was used to distinguish between the pronated foot and control groups. The Zebris FDM (Zebris Medical GmbH) stance analysis system was used to measure the FPD on the dominant side during a SLS, which was divided into three phases. A two-way mixed-model ANOVA was used to identify significant differences in FPD between and within the two groups. Results: In the hallux, the results of the two-way mixed-model ANOVAs revealed a significant difference between the group and across different phases (p < 0.05). The hallux, and central forefoot were significantly different between the group (p < 0.05). Moreover, significant differences across different phases were observed in the hallux, medial forefoot, central forefoot, lateral forefoot, and rearfoot (p < 0.05). The post hoc t-tests were conducted for the hallux and forefoot central regions. In participants with pronated foot, the mean pressure was significantly greater in hallux and significantly lower, in the central forefoot during the descent and holding phases. Conclusion: SLSs are widely used as screening tests and exercises. These findings suggest that individuals with pronated feet should be cautious to avoid excessive pressure on the hallux during the descent-to-hold phase of a SLS.
        4,000원
        74.
        2024.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Sleep accounts for approximately one-third of a person’s lifetime. It is a relaxing activity that relieves mental and physical fatigue. Pillows of different sizes, shapes, and materials have been designed to improve sleep quality by achieving an optimal sleep posture. Objects: This study aimed to determine which pillow provides the most comfortable and supports the head and neck during sleep, which may enhance sleep quality. Methods: Twenty-eight healthy adults (19 males and 9 females) with an average age of 29 years participated in this cross-sectional study. This experiment was conducted while the participants laid down for 5 minutes in four different pillow conditions: (1) no pillow (NP), (2) neck support foam pillow (NSFP), (3) standard microfiber filled pillow (SFP), and (4) hybrid foam pillow (HFP). The head-neck peak pressure, cranio-vertebral angle in supine (CVAs), cranio-horizontal angle in supine (CHAs), chin-sternum distance (CSD), and muscle tone of sternocleidomastoid were analyzed using one-way repeated measures analysis of variance (ANOVA). The significance level was set at p < 0.05. Results: The head-neck peak pressure was the highest in the NSFP condition, followed by the NP, SFP, and HFP conditions. The CVAs, CHAs, and CSD of the SFP were lower than those of the other pillows. Muscle tone was the highest in the NP condition, followed by the of NSFP, HFP, and SFP conditions. The participants subjective comfort level in both the supine and side-lying postures was highest in the HFP condition, followed by the SFP and NSFP conditions. Conclusion: This study can be used to establish the importance of pillow selection for highquality sleep. The results of this study, suggest that a hybrid pillow with a good supportive core and appropriate fluffiness can maintain comfort and correct cervical spine alignment during sleep.
        4,000원
        75.
        2024.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        제3차 도서관발전종합계획(2019-2023)에 따라 공공도서관 확충이 진행되는 시점에서, 현재의 공공도서관 공급이 각 지역민 의 공평한 접근성을 고려하여 설립되고 있는지 분석할 필요가 있다. 본 연구는 전국의 공공도서관 분포를 바탕으로 도서관의 서비스 영향 범위를 분석하여, 거리 접근성 관점에서 공공도서관의 서비스 현황을 분석하고자 한다. 이에 2015년과 2022년의 도서관 정보와 격자 기반의 인구수를 중첩하여, 공공도서관의 서비스 비율을 도출하였다. 도출 결과는 공공도서관 전체와 교육청을 분리하여 시각화하였으며, 이를 통해 영향권에 따른 시기별 추이 변화를 확인할 수 있다. 이를 바탕으로 공공도서관 접근성 강화와 도서관 서비스 활성화 방안을 제시하였다. 또한 분석 결과로 도출된 지도는 향후 공공도서관 건립 또는 정책 마련 시에 근거자료로 활용될 수 있을 것이다.
        4,300원
        76.
        2024.04 구독 인증기관·개인회원 무료
        세계 100대 악성 침입외래종인 유리알락하늘소(Anoplophora glabripennis)와 근연종인 노랑알락하늘소(가 칭, Anoplophora horsfieldii (Hope, 1843))가 2019년 제주도에서 처음 발견된 후 2023년까지 지속적으로 확인되었 다. 본 연구는 MaxEnt 알고리즘을 기반으로 하는 생물종 분포 모델을 이용하여 19개의 기후변화 변수에 노랑알락 하늘소(가칭) 먹이식물 5종(차나무, 팽나무, 멀구슬나무, 종가시나무, 비술나무)의 변수를 추가하여 외래해충인 노랑알락하늘소(가칭)의 현재·미래의 분포 가능지역에 대한 공간적 분포 특성을 규명하고 국가적 확산을 대응 하고자 한다. 모델 예측 정확도(AUC)는 0.983으로 출현지점을 정확하게 예측하는 비율이 매우 높다고 할 수 있다. 모델 예측 정확도의 증감에 영향을 주는 환경변수 중 먹이식물의 기여도가 70%를 상회하는 것으로 나타났다. 현재 75% 이상 분포 가능지역은 전라남도 진도군 일대와 경상북도 포항시 일대로 나타났으나 2050년에는 서해안을 따라 태안군까지 동해안을 따라 북한의 고성군까지 분포가 가능한 것으로 나타났다. 또한 75% 이상 분포 가능 면적은 현재 423㎢에서 2050년에는 9,270㎢로 약 대한민국 면적의 1/10 정도 확산될 것으로 예측된다.
        77.
        2024.04 구독 인증기관·개인회원 무료
        Field surveys were conducted to collect and refine "Natural resource survey" and ecosystem research data of 23 National parks in South Korea, including Hallasan on Jeju Island and Palgongsan newly designated as national park in 2023. Among the collected data, a total of 1,538 species from 54 families of Hymenoptera insects were recorded. Within these families, the largest number of species was recorded in the family Ichneumonidae with 514 species, followed by Formicidae (118 species), Braconidae (112 species), and Tenthredinidae (135 species), exhibiting relatively high species diversity. Among the National parks, Jirisan, the first designated National park in South Korea with a relatively large area compared to other parks, recorded the highest species diversity with 618 species, while Taebaeksan recorded relatively low species diversity with 77 species. Correlation analysis between the number of Hymenoptera species and other factors revealed a statistically significant and relatively strong positive correlation (P > 0.005, R = 0.864) with the total number of insects, and a statistically significant but relatively weak positive correlation (P > 0.005, R = 0.615) with the park's area.
        78.
        2024.04 구독 인증기관·개인회원 무료
        Oriental fruit flies (Bactrocera dorsalis) are one of the most important pests in horticulture worldwide. The distribution information of this species is not easy to be found as it is scattered in many forms of publications such as books, journals, and research reports. The study was conducted by collecting data from various resources, analyzing the information, and interpreting the results. As a result, B. dorsalis was confirmed to be distributed in a total of 82 countries, and the distribution status of each country is presented by dividing it into present (widespread, localized, few occurrences, under eradication) and absent (eradicated, confirmed by survey, intercepted only, invalid presence record). This review is very useful for biologists, entomologists, as well as practitioners of plant protection.
        79.
        2024.04 구독 인증기관·개인회원 무료
        Neomyrhessus Minkina, 2024, is a rare genus comprising six species, recently erected from Myrhessus Balthasar, 1955 for N. nanjingensis. To date, all six species have been reported in East Asia, with five from Japan and one from China. In this study, the genus Neomyrhessus is recorded for the first time in South Korea, with the discovery of a new species Neomyrhessus coreanus sp. nov. Description, illustrations of morphological characters, and habitat information for a new species are provided.
        80.
        2024.04 구독 인증기관·개인회원 무료
        Dysmicoccus brevipes (Cockerell), Dysmicoccus neobrevipes Beardsley and Pseudococcus longispinus (Targioni-Tozzetti) are widely-distributed pests that feeds on many economically important hosts, particularly tropical fruits and ornamentals. The potential distribution of these mealybug pests into South Korea remains a primary concern because of their high incidence in interceptions screened during inspection. Hence, these species prompted a modelling effort to assess their potential risk of introduction. Potential risk maps were developed for these pests with the CLIMEX model based on occurrence records under environmental data. The potential distribution of these pests in South Korea in the 2020s, 2050s and 2090s was projected based on the RCP 8.5 climate change scenario. Results show that D. brevipes, D. neobrevipes and P. longispinus have little potential for invasion in the exterior environment of South Korea due to high cold stress in the 2020s. However, for D. brevipes and P. longispinus, 3 and 86 locations in Jejudo, were predicted to be marginally suitable for this pest under future climate factors, respectively. In that respect, the results of these model predictions could be used to prepare a risk-based surveying program that improves the probability of detecting early D. brevipe, D. neobrevipes and P. longispinus populations.
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