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        검색결과 1,368

        1.
        2024.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : This study aimed to predict the number of future COVID-19 confirmed cases more accurately using public and transportation big data and suggested priorities for introducing major policies by region. METHODS : Prediction analysis was performed using a long short-term memory (LSTM) model with excellent prediction accuracy for time-series data. Random forest (RF) classification analysis was used to derive regional priorities and major influencing factors. RESULTS : Based on the daily number of COVID-19 confirmed cases from January 26 to December 12, 2020, as well as the daily number of confirmed cases in Gyeonggi Province, which was expected to occur on December 24 and 25, depending on social distancing, the accuracy of the LSTM artificial neural network was approximately 95.8%. In addition, as a result of deriving the major influencing factors of COVID-19 through random forest classification analysis, according to the number of people, social distancing stages, and masks worn, Bucheon, Yongin, and Pyeongtaek were identified as regions expected to be at high risk in the future. CONCLUSIONS : The results of this study can help predict pandemics such as COVID-19.
        4,000원
        2.
        2024.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The common snapping turtle (Chelydra serpentina), which is native to North America, started to be imported into South Korea as pets in the 1990s. The turtle was sold in supermarkets and pet shops nationwide at low prices such as 20 USD. These non-native turtles, with their large size and strong predatory nature, have been consistently discovered in the wild in South Korea beginning in 2014, and they were designated as an ecosystem-disturbing species (EDS) in October 2022. Until June 30, 2023, a collection system was implemented to reduce the abandonment problem of C. serpentina due to their designation as an EDS. In this study, we analyzed the impacts of the legal designation as an ecologically disturbing species and the collection system of C. serpentina on their abandonment and surrender. Our findings showed that designation as EDS did not affect the abandonment of C. serpentina. Meanwhile, the collection system led to cases of immediate surrender. Within 3 years of post-purchase, 41.8% of the turtles were surrendered, and 67.5% were surrendered when they reached 3 kg. Determining the impact of the legal designation as an EDS may be currently limited due to the difficulty of detecting C. serpentina in the wild. On the other hand, cases of surrender through the collection system are considered to be effective as they have been shown to reduce the abandonment of this newly designated ecosystem-disturbing species.
        4,000원
        3.
        2024.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Most wetlands worldwide have suffered from extensive human exploitation. Unfortunately they have been less explored compared to river and lake ecosystems despite their ecological importance and economic values. This is the same case in Korea. This study was aimed to estimate the assemblage attributes and distribution characteristics of benthic macroinvertebrates for fifty wetlands distributed throughout subtropical Jeju Island in 2021. A total of 133 taxa were identified during survey periods belonging to 53 families, 19 orders, 5 classes and 3 phyla. Taxa richness ranged from 4 to 31 taxa per wetland with an average of 17.5 taxa. Taxa richness and abundance of predatory insect groups such as Odonata, Hemiptera and Coleoptera respectively accounted for 67.7% and 68.2% of the total. Among them Coleoptera were the most diverse and abundant. Taxa richness and abundance did not significantly differ from each wetland type classified in accordance with the National Wetland Classification System. There were three endangered species (Clithon retropictum, Lethocerus deyrolli and Cybister (Cybister) chinensis) and several restrictively distributed species only in Jeju Island. Cluster analysis based on the similarity in the benthic macroinvertebrate composition largely classified 50 wetlands into two major clusters: small wetlands located in lowland areas and medium-sized wetlands in middle mountainous regions. All cluster groups displayed significant differences in wetland area, long axis, percentage of fine particles and macrophyte composition ratio. Indicator Species Analysis selected 19 important indicators with the highest indicator value of Ceriagrion melanurum at 63%, followed by Noterus japonicus (59%) and Polypylis hemisphaerula (58%). Our results are expected to provide fundamental information on the biodiversity and habitat environments for benthic macroinvertebrates in wetland ecosystems, consequently helping to establish conservation and restoration plans for small wetlands relatively vulnerable to human disturbance.
        4,900원
        4.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 유색과 백색품종 토종오리의 성별에 따른 생산능력과 도체특성을 평가하고자 실시하였다. 1일령 토종오리 총 480수를 2개 품종(유색과 백색)×2개 성별(암컷과 수컷)로 총 4처리구의 4반복으로 반복 당 30수씩 평사에 나누어 8주간 사양실험을 진행하였다. 본 연구결과, 전체 사양실험기 간에서 토종오리의 체중, 증체량 및 사료섭취량은 품종(유색과 백색) 간 차이는 없었으나 수컷이 암컷보다 유의적으로 높았다(p<0.05). 이와 유사하게, 사료요구율은 유색품종과 백색품종의 차이가 없었으나 수컷이 암컷에 비해 유의적으로 개선됨을 확인하였다(p<0.05). 토종오리의 머리, 가슴육, 다리육 및 간의 무게는 처리구간 통계적 차이를 나타내지 않았다. 도체중량은 처리구간 차이가 없었으나, 도체율은 백색품종이 유색품종과 비교해 현저히 높았다(p<0.05). 또한 복강지방 무게는 수컷이 암컷에 비해 높았으며(p<0.05) 백색품종이 유색품종보다 높았다(p<0.05). 폐사율은 토종오리 의 품종과 성별에 따른 유의적 차이가 없었다. 본 연구결과는 토종오리의 육성기 단계에서 사육성적에 대한 기초자료로 이용될 것으로 사료된다.
        4,000원
        5.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Human and material damage can be reduced if the risk is evaluated by engineering analysis of fire combustion products, smoke concentration, and smoke movement speed in the event of a fire in apartment houses and officetels. In this study, a lot of research on related safety evaluation in the basement needs to be studied and reflected in design, so experimental research was conducted to analyze the flow of smoke through computer simulation and provide analysis data through evacuation safety evaluation. First of all, the five-story underground parking lot subject to simulation has a large floor area, which is advantageous for improving evacuation safety performance, but it uses temperature detectors to increase detection time and fire spread speed. Second, it was analyzed that the evacuation time at all evacuation ports did not exceed the evacuation time, and as the time from the start of evacuation to the evacuation time was 216.9% compared to the travel time, it was evaluated that the safety performance of the evacuation was secured. Third, the above simulation results are a comprehensive safety evaluation based on the non-operation of fire extinguishing facilities in the fire room to increase safety, which means that smoother evacuation safety performance can be secured by linking fire extinguishing facilities.
        4,000원
        10.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study is in order to the effect of 1-methlycyclopropene (1-MCP) treatment and film package as modified atmosphere packaging (MAP) on the changes in fruit quality factors of 'Daehong' peaches during cold storage. The concentrations of 1-MCP were treated at 1μL·L-1 and 2μL·L-1, and peaches in film package were stored for 28 days in cold storage at 5±1°C and 85±5% RH. The fruits stored carton box were used as a control of MAP, and 1-MCP free fruits were used as the control of both packages. Rate of fresh weight loss during storage was not significantly different between groups with and without 1-MCP treatment, but was higher in the box package than in the MAP. The control group had a higher incidence of both gases with the 1-MCP treatment group showing statistically significantly low. Carbon dioxide in the package was lowered by about 12% compared to the non-treated group, and the ethylene concentration was maintained at 1μL·L-1, showing a significance low compared to other treated groups. As the storage period elapsed, the firmness of 1-MCP and MAP treated fruits remained significant at 5-9% compared to the control group. Regardless of the packaging method Hunter a* values of exocarp and mesocarp were significantly higher in fruit treated with 1-MCP 1μL·L-1 treatment than in the control group, and anthocyanin was significantly higher in the fruit during the storage period, especially high in MAP. In summary, fruits of MAP group with 1-MCP 1μL·L-1 had rate of lower respiration and ethylene production, and little changes in firmness, Hunter a* values of exo-carp and meso-carp, and anthocyanin, which is considered the most suitable method for preserving postharvest quality of the peach cultivar during the storage.
        4,200원
        11.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : The main purpose of this study is to identify vulnerable areas by evaluating public transit accessibility for the introduction of smart mobility. METHODS : This study proposes a methodology for analyzing public transportation accessibility. We identified the less accessible areas of public transit in Daegu Metropolitan City by dividing them into low- and high-facilitated areas considering travel demand and developed plans to introduce smart mobility based on the analysis results. RESULTS : Areas vulnerable to public transportation in Daegu Metropolitan City can be divided into those with low public transportation accessibility and low usage rates, those with good public transportation accessibility but low usage rates, and those with low public transportation accessibility but high usage rates. CONCLUSIONS : Based on the results of this study, it is possible to introduce customized services for each area with poor public transit accessibility, and some of the inconveniences experienced by citizens using public transit are expected to be resolved.
        4,000원
        15.
        2023.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The invasive red swamp crayfish, Procambarus clarkii, is native to southcentral United States and northeastern Mexico. Recently, it has been being spreading in the wild in South Korea. However, its primary sources, introduction routes, establishment, and expansion in South Korea remain unclear. Here, we analyzed genetic diversity and population genetic structures of its domestic natural populations during early invasion, commercial stock from local aquaria (a suspected introduction source), and original United States population using mitochondrial COI gene sequences for 267 individuals and eight microsatellite markers for 158 individuals. Natural and commercial populations of P. clarkii showed reduced genetic diversity (e.g., haplotype diversity and allelic richness). The highest genetic diversity was observed in one original source population based on both genetic markers. Despite a large number of individuals in commercial aquaria, we detected remarkably low genetic diversity and only three haplotypes among 226 individuals, suggesting an inbred population likely originating from a small founder group. Additionally, the low genetic diversity in the natural population indicates a small effective population size during early establishment of P. clarkii in South Korea. Interestingly, genetic differentiation between natural populations and the United States population was lower than that between natural populations and aquarium populations. This suggests that various genetic types from the United States likely have entered different domestic aquariums, leading to distinct natural populations through separate pathways. Results of our study will provide an insight on the level of genetic divergence and population differentiation during the initial stage of invasion of non-indigenous species into new environments.
        4,000원
        16.
        2023.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The annual reproductive cycle of two species, Upogebia major (de Haan 1841) and Austinogebia wuhsienweni (Yu 1931), of the female mud shrimp from the west coast of Korea was investigated using histology. The collected samples were divided into adult and juvenile groups to understand the mature period of age class based on the carapace length (CL). Juvenile Upogebia (CL<25 mm) were mostly inactive gonad with early (62%-100%) and late (10%-38%) development stages during the year, whereas the adult shrimp showed a seasonal pattern of gonad maturation (CL≥25 mm). The early and late developmental stages of oocytes were observed in adult Upogebia from November to March and mature eggs appeared from April to October. In adult Ausitnogebia (CL≥15 mm), fully grown oocytes were consistently observed during the study period, in which the ripe stage was found between January and June. On the other hand, most juvenile Austinogebia (CL<15 mm) maintained an immature state in the gonad. Both species of the mud shrimp reproduced from ovigerous females in the adult population and their egg-bearing period was distinguished from January to April for U. major and from July to September for A. wuhsienweni.
        4,000원
        17.
        2023.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The aim of this study was to compare the antioxidant activities and functional contents of Korean conventional and Chinese seed gingers from the Jeollabuk-do Wanju and Chungcheongnam-do Seosan regions. Ginger samples were subjected to steaming treatments for different durations (2–8 h) at 121oC using an autoclave. The antioxidant activity was evaluated by measuring total polyphenol and flavonoid contents and ABTS and DPPH radical scavenging activities, while functional ingredient contents were analyzed for gingerols and shogaols. The results showed that Wanju conventional seed ginger (WO-2) had the highest total polyphenol (85.24 mg GAE/g) and flavonoid (98.14 RE/100 g) contents, surpassing that of the control in all steamed groups at 6 h. ABTS radical scavenging activity showed a strong correlation with total polyphenol and flavonoid contents. The control groups indicated that Korean conventional seed ginger had 1.0–1.3 times higher gingerol contents compared to Chinese seed ginger. Furthermore, the content of shogaols, considered major functional ingredients, increased significantly with longer steaming durations, reaching the highest content (1,793 mg/kg) at 8 h, which was 1.0–1.8 times higher in Korean conventional seed ginger than that in Chinese seed ginger. These experiments provide valuable data supporting the excellence of Korean conventional seed ginger in the future.
        4,000원
        18.
        2023.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 에너지 저장 응용을 위한 PVI-PGMA/LiTFSI 고분자 막 전해질 및 CxNy-C 유연 전극의 합성 및 특성 에 관한 연구이다. 이중 기능을 갖는 PVI-PGMA 공중합체는 우수한 이온 전도성을 나타내었으며, PVI-GMA73/LiTFSI200 막 전해질은 1.0 × 10-3 S cm-1의 최고 전도도를 달성하였다. CxNy-C 전극의 전기화학적 성능을 체계적으로 분석하였으며, C3N2-C는 나노와이어와 다면체로 구성된 높은 연결성을 갖는 하이브리드 구조와 이중 Co/Ni 산화물을 포함하여 풍부한 산 화환원 활성 부위와 이온 확산을 용이하게 하는 특징으로 인해 958 F g-1의 최고용량 및 최소한의 전하 전달 저항(Rct)을 달성 하였다. 흑연 탄소 껍질의 존재는 충전-방전 동안 높은 전기화학적 안정성에 기여하였다. 이러한 결과들은 고성능 에너지 저 장 장치인 슈퍼커패시터 및 리튬 이온 전지와 같은 첨단 에너지 저장 장비에 PVI-PGMA/LiTFSI 고분자 막 전해질과 CxNy-C 전극을 활용하는 잠재력을 보여주었으며, 지속 가능하고 고성능의 에너지 저장 기술을 더욱 발전시키는 길을 열어가 고 있다.
        4,200원
        19.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study focused on using indirect filtration through riverbeds to produce high-quality drinking water. Data on water quality from a water intake facility(capacity 10,000 m3/day) and nearby rivers were collected over a three-year period. The average intake facility specifications were found to be a specific surface area of 58 balls/m2, a mean particle size of 24 mm, an inflow velocity of 2.2 cm/sec, and a burial depth of 5 m. The water quality improvement rate was assessed as grade Ia, surpassing the adjacent river’s water quality. Correlation analysis showed a weak correlation between opening ratio, Suspended Solid (SS), and Biochemical Oxygen Demand (BOD) compared to total coliforms and fecal coliforms. The correlation coefficient R value of SS was -0.614, BOD was –0.588, total coliforms -0.870, and fecal coliforms -0.958. The R value shows a negative value, which showed that the larger the opening rate, the lower the removal rate of water pollutants. The correlation coefficient R values according to the depth of burial were found to be BOD 0.914, SS-0.124, total coliforms 1.000, and fecal coliforms 0.866. The deeper the burial depth, the higher the removal rate of BOD and microbial groups.
        4,000원
        20.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        우리나라는 무기질비료 사용량이 많은 나라 중 하나이다. 그러나 1980년 이후 지속가능농업에 대한 필요성에 의해 1997년 친환경 농업육성법이 제정되었고 지속가능한 농업을 위한 연구로 논, 밭, 시설 및 과수에 대한 비료사용실태조사가 실시되고 있다. 이에 본 연구는 과수 중 대표되는 7작물(배, 포도, 사과, 복숭아, 대추, 단감, 키위)을 대상으로 각 도에서 805농가를 선정하여 실시하였으며, 조사내용은 사용하는 비료의 종류, 사용량 등에 대해 농가를 방문하여 면접 청취조사하였다. 국내 과수작물의 성분별 평균 비료사용량(N-P2O5-K2O)은 30.0-23.8-24.3 kg 10a-1이었으 며 비료 종류별로 구분하였을 때 퇴비 > 유기질비료 > 무기질비료 순으로 사용하고 있었다. 단위면적당 가장 많은 비료를 사용하고 있는 과수는 대추로 질소, 인산 및 칼리를 평균 53.3-42.0-49.5 kg 10a-1을 사용하고 있는 것으로 확인되었다. 앞으로 지속가능 농업과 농업환경의 보전을 위해서는 농가에서 사용하는 비료의 장기간 모니터링 뿐만 아니라 농업인에게 무기질비료, 유기질비료 및 퇴비의 적정사용방법에 대한 교육 및 홍보를 지속적으로 실시해야 될 것으로 판단된다.
        4,000원
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