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        검색결과 918

        1.
        2024.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The pressure sensor had been widely used to effectively monitor the flow status of the water distribution system for ensuring the reliable water supply to urban residents for providing the prompt response to potential issues such as burst and leakage. This study aims to present a method for evaluating the performance of pressure sensors in an existing water distribution system using transient data from a field pipeline system. The water distribution system in Y District, D Metropolitan City, was selected for this research. The pressure data was collected using low-accuracy pressure sensors, capturing two types of data: daily data with 1Hz and high-frequency recording data (200 Hz) according to specific transient events. The analysis of these data was grounded in the information theory, introducing entropy as a measure of the information content within the signal. This method makes it possible to evaluate the performance of pressure sensors, including identifying the most sensitive point from daily data and determining the possible errors in data collected from designated pressure sensors.
        4,200원
        2.
        2024.10 구독 인증기관·개인회원 무료
        이 연구에서는 해양폐기물인 해조류에서 추출된 알긴산을 혼입하여 모르타르의 압축강도 특성을 분석하였다. 알긴산은 해양폐기물 중 해조류의 성분 중 하나로 라텍스와 비슷한 성분을 띄고 있으며, 방수성 성질이 있어 포장용 콘크리트에 활용 시 콘크리트의 수명 을 연장하고 파손 방지에 도움이 된다. 따라서 이 연구에서는 기존에 널리 사용되고 있는 라텍스 콘크리트에 알긴산을 혼입한 라텍스 콘크리트 개발의 일환으로 알긴산 혼입 라텍스 모르타르의 역학적 특성에 대한 실험적 연구를 수행하였다. 실험결과, 알긴산 혼입량 증가에 따른 응결은 빨라지는 경향을 나타내었으며, 압축강도는 저하하는 경향을 나타내었다.
        3.
        2024.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In South Korea, over 400,000 Non-building Structures are inadequately managed and exposed to potential risks due to insufficient inspection systems, leading to an increase in accidents and significant losses of life and property. Therefore, it is crucial for users to conduct proactive self-inspections to identify and mitigate potential hazards. This study reclassified Non-building Structures into four main categories by analyzing their structural characteristics and associated risks through statistical analysis. Among these, retaining walls, which account for the largest proportion, were systematically analyzed to identify common damage patterns. Based on this analysis, self-inspection checklists were developed for both non-experts and experts. The proposed process involves an initial visual inspection using a simple non-expert checklist, followed by a more detailed expert-level inspection if any anomalies are detected. The reliability of this process was validated through approximately 120 validation processes.
        4,500원
        4.
        2024.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        High-rise buildings are equipped with TMD (Tuned Mass Damper), a vibration control device that ensure the stability and usability of the building. In this study, the seismic response control performance was evaluated by selecting the design variables of the TMD based on the installation location of the twisted irregular building. To this end, we selected analysis models of 60, 80, and 100 floors with a twist angle of 1 degree per floor, and performed time history analysis by applying historical seismic loads and resonant harmonic loads. The total mass ratio of TMDs was set to 1.0%, and the distributed installation locations of TMDs were selected through mode analysis. The analysis results showed that the top-floor displacement responses of all analysis models increased, but the maximum story drift ratio decreased. In order to secure the seismic response control performance by distributed installation of TMDs in twisted irregular buildings, it is judged that the mass ratio distribution of TMDs will act as a key variable.
        4,000원
        5.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study aimed to provide ecological information by identifying the stand characteristics of Larix kaempferi forest vegetation (deforestation, forest influence, patch, forest) for aggregated retention harvest in Mt. Nambyeongsan, Pyeongchang- Gun. Data were collected using the Braun-Blanquet vegetation survey method from July 2020, with 54 quadrats analyzed for importance value, species diversity, similarity index, and detrended correspondence analysis (DCA). The results showed that vine species had a higher importance value in the deforestation area and forest influence area. Forest regions had the highest species diversity (2.419), while the forest influence area had the lowest (2.171). The similarity index was highest between the forest region and patch area (0.723), and lowest between the patch area and forest influence area (0.658), which was consistent with the DCA results. In conclusion, although species diversity temporarily showed higher values in the initial stage after aggregated retention harvest, it was difficult to assign ecologically specific meanings to these values. Long-term monitoring is therefore necessary to accumulate ecological information on aggregated retention harvests.
        4,200원
        9.
        2024.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        유통 중인 생분해성 합성수지로 만들어진 식품용 기구 및 위생용품 50건을 대상으로 ‘식품용 기구 및 용기·포장 공전’의 기준·규격을 검사하였다. PLA 재질의 유아식기 1 건에서 ‘과망간산칼륨소비량’이 20mg/L으로 기준치(10 mg/ L 이하)를 초과하였고, 그 외 모든 시료에서는 포름알데히 드, 납, 비소 등이 기준·규격 이하로 안전한 수준이었다. 또한 가정에서 유아식기를 소독하는 방법의 안전성을 조 사하기 위해, PLA 재질의 유아식기(n=21)에서 반복적인 열탕소독과 자외선 조사에 따른 이행량의 변화를 조사하였다. 반복적인 열탕소독이 자외선 조사에 비해 포름알데 히드와 비소의 이행량이 많았으나, 이행량은 매우 낮은 수 준이었다. 그리고 유아(만 1-3세) 기준으로 계산한 포름알 데히드와 비소의 일일추정섭취량(EDI)은 최대 6.0×10-4mg/ kg b.w./day 및 1.3×10-1 μg/kg b.w./day였으며, 이는 일일섭 취한계량(TDI, 0.15 mg/kg b.w./day) 및 잠정주간섭취허용 량(PTWI, 9.0 μg/kg b.w./week)의 0.40% 및 10.42%로 낮 은 수준임을 확인하였다. 따라서 현 국내에서 유통되고 있 는 식품용 생분해성 합성수지제는 안전한 수준임을 확인 하였다.
        4,000원
        10.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구의 목적은 알츠하이머질환(Alzheimer’s disease: AD) 동물 모델을 대상으로 트레드밀 운 동(Treadmill exercise: TE)과 환경강화(environmental enrichment: EE) 처치가 인지기능, 근 기능, 및 밀 착연접 단백질 발현에 미치는 영향을 확인하는데 있다. AD 동물 모델을 제작하기 위해 aluminum chloride(AlCl3)를 90일간(40mg/kg/하루) 투여 하였으며 동시에 TE(10-12m/min, 40-60min/day) 혹은 EE에 노출시켰다. 그 결과 AlCl3 투여에 의한 인지기능 저하와 근 기능 감소가 TE와 EE에 의해 완화된 것 으로 나타났다. 또한, TE와 EE는 AD 질환에서 나타나는 β-amyloid(Aβ), alpha-synuclein 및 tumor necrosis factor-α(TNF-α) 단백질의 발현 증가를 감소시킨 것으로 나타났다. 게다가 TE와 EE는 AlCl3 투여에 의해 감소된 밀착연접 단백질(Occludin, Claudin-5 및 ZO-1)의 발현을 통계적으로 유의하게 증가시킨 것으로 나타났다. 마지막으로 Aβ 단백질과 밀착연접 단백질과의 상관분석을 실시한 결과 부적 상 관관계(Occludin: r=-0.853, p=0.001; Claudin-5 : r=-0.352, p=0.915; ZO-1 : r=-0.424, p=0.0390) 로 나타났다. 따라서 이를 종합해 보면 TE 혹은 EE 처치는 AD에 나타나는 병리학적 특징들을 일부 완화 시켜 인지기능과 근 기능을 일부 개선 시킬 수 있는 효과적인 운동 방법이라고 생각된다.
        4,200원
        11.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구의 목적은 컨테이너 육묘 시스템을 활용한 참외 접목 묘의 안정적인 생산 가능성을 평가하는 것이었다. 이를 위해, 컨테이너 육묘 시스템과 고온 조건의 플라스틱 온실에서 육묘 한 접수와 대목, 접목묘의 생육을 비교 분석하였다. 접목활착 후 육묘 환경에 따른 참외 접목묘의 생육과 묘소질을 0일, 4일, 7일, 11일, 14일째에 비교하였다. 컨테이너 육묘 시스템에서 는 주야간 온도를 25/20°C, 상대습도를 70%로 설정하여 재 배기간 동안 안정적으로 유지하였으며, 플라스틱 온실 내의 주야간 평균온도는 28.1/15.4°C로 주야간 온도차(DIF)가 더 크게 나타났다. 조사기간 동안 참외 접목묘의 초장은 플라스 틱 온실 육묘 처리구에서 컨테이너 육묘 시스템 처리구보다 더 길게 나타났다. 참외 접목묘 조직의 충실도는 지상부 건물 중을 초장으로 나누어 계산하였다. 육묘장에서 접목한 묘는 접목 후 7-10일 경과하여 활착이 완료되고 초장이 10cm 내 외일 때 출하하여 정식에 이용되게 된다. 본 연구에서 접목활 착 후 7일째에 컨테이너 육묘 시스템에서 재배된 묘의 충실도 는 44.9±2.64mg/cm으로 나타났으며, 플라스틱 온실 육묘 처 리구에서는 24.4±1.56mg/cm로 나타났다. SPAD 평균은 플 라스틱 온실 육묘에서 30.5, 컨테이너 육묘 시스템에서 41.1 로 측정되었다. 이러한 결과는 컨테이너 육묘 시스템의 활용 이 고온기 또는 저일조 시기와 같은 육묘 환경에서도 고품질 모종을 안정적으로 생산할 수 있는 것을 확인하였고, 인공광 을 이용한 육묘 시스템의 활용 범위가 앞으로 더 확대될 것으 로 기대된다.
        4,000원
        12.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated the effect of Lactiplantibacillus plantarum JSA22-fermented rice drinks on dextran sodium sulfate (DSS)-induced colitis in mice. Twenty-four mice were randomly assigned; No colitis (Con), colitis with tap water (DSS-only), colitis with unfermented rice (DSS-UFR), and colitis with fermented rice (DSS-FR). After inducing colitis with 2% DSS for 5 days, they were given Tap water, UFR drink, or FR drink for an additional 6 days. The DSS-FR group had significantly lower Disease Activity Index (DAI) scores compared to the DSS-only group, but no significant difference with the DSS-UFR group. Colon length was reduced in the DSS-only group. The DSS-only group had significantly higher IL-6 mRNA levels compared to the Con group, while the DSS-FR groups showed significantly lower IL-6 mRNA levels compared to the DSS-only group. These results suggest that rice drinks fermented with Lactiplantibacillus Plantarum JSA22 ameliorate the severity of DSS-colitis, by potentially reducing proinflammatory cytokines.
        4,000원
        13.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 고투과성 및 높은 염 제거율을 가지는 역삼투막의 성능향상을 위하여 다양한 첨가제 및 계면중합 시 경화 온도 및 시간에 따른 특성평가에 대한 연구가 수행되었다. 첨가제가 없는 막과 첨가제를 첨가한 막의 모폴로지는 모 두 “ridge-and-valley” 구조를 나타내어, 폴리아미드 층이 다공성 지지층 표면에 성공적으로 중합되었음을 확인하였다. 또한 2-Ethyl-1,3-hexanediol (EHD) 첨가함으로써 향상된 친수성과 수투과율 가졌으며, 이는 접촉각 측정을 통해서 확인되었다. 최 종적으로 97.78%와 98.7%의 NaCl 및 MgSO4 제거율과 3.31 L/(m2⋅h⋅bar)의 높은 수투과율을 가진 고투과성 계면중합막을 제조하였다.
        4,300원
        14.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 중공사형 이산화탄소 분리막 모듈을 사용하여 수소개질기 배가스로부터 이산화탄소 포집을 목적 으로 한 분리막 공정 최적화 연구를 진행하였다. 랩스케일의 소형 분리막 모듈을 사용하여 혼합기체를 대상으로 이산화탄소 순도 90% 및 회수율 90%을 달성하는 2단 공정 조건을 도출하였다. 막 면적이 정해진 모듈의 분리막 공정에서는 스테이지-컷, 주입부 및 투과부 압력에 따라서 포집 순도 및 회수율이 모두 다르게 나타나기 때문에 운전 조건에 대한 최적화가 필수적이 다. 본 연구에서는 다양한 운전 조건에서 1단 분리막에서 보이는 공정 포집 효율의 한계를 확인하고, 높은 순도와 회수율을 동시에 달성하기 위한 2단 회수 공정을 최적화하였다.
        4,000원
        15.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study addresses the optimal design methodology for switching between active electronically scanned array (AESA) radar operating modes to easily select the necessary information to reduce pilots' cognitive load and physical workload in situations where diverse and complex information is continuously provided. This study presents a procedure for defining a hidden Markov chain model (HMM) for modeling operating mode changes based on time series data on the operating modes of the AESA radar used by pilots while performing mission scenarios with inherent uncertainty. Furthermore, based on a transition probability matrix (TPM) of the HMM, this study presents a mathematical programming model for proposing the optimal structural design of AESA radar operating modes considering the manipulation method of a hands on throttle-and-stick (HOTAS). Fighter pilots select and activate the menu key for an AESA radar operation mode by manipulating the HOTAS’s rotary and toggle controllers. Therefore, this study presents an optimization problem to propose the optimal structural design of the menu keys so that the pilot can easily change the menu keys to suit the operational environment. K
        4,500원
        16.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Tomato is one of the major widely cultivated crops around the world. The leaf area is directly related to the total amount of photosynthesis, which affects the yield and quality of the fruit. Traditional methods of measuring the leaf area are time-consuming and can cause damage to the leaves. To address these problems, various studies are being conducted for measuring the leaf area. In this study, we introduced a model to estimate the leaf area using images of tomatoes. Using images captured by a camera, we measured the leaf length and width and used linear regression analysis to derive the leaf area estimation formula. Furthermore, we used a Neural Network (NN) for additional analysis to compare the accuracy of the models. Initially, to verify the reliability of the image data, we conducted a correlation analysis between the actual measurement data and the image data, which showed a high positive correlation. The leaf area estimation model presented 23 estimation formulas. We used regression analysis to estimate the coefficients of each model and also used employed an artificial neural network analysis to derive high R-squared (R2) values and low Root Mean Square Error (RMSE) values. Among the estimation formulas, the ninth model showed the highest reliability with an R-squared value of 0.863. We conducted a verification experiment to confirm the accuracy of the selected model, and the R-squared value was 0.925. This study confirmed the reliability of data measured from images and the reliability of the leaf area estimation model using image data. These methods are expected to be an important tool in agriculture, using imaging equipment for measuring and monitoring the crop growth.
        4,000원
        17.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This research aims to investigate Park Kilyong’s architectural theory and critique of Gyeongseong (Seoul) buildings, expressed in his ‘Overview of Modern Buildings in Gyeongseong’ and ‘Critique of Gyeongseong Buildings’ (Samcheolli, Sept. and Oct. 1935); and ‘Architectural Form of the 100% Function’ and ‘The Modern and Architecture (1)-(4)’ (Dong-A Daily, 28 Jul. to 1 Aug. 1936). As a result, it is confirmed that Park had the functionalist theory of modern architecture, which suggests that Korean architects of the Japanese colonial period were accommodating the contemporary trend of world architecture. However, Park shows his fundamental limitations in the fact that the main content of his articles was a verbatim translation of two Japanese references (Kurata, 1927; Ishihara, 1929) without proper indications. Despite the limitations, his texts are still meaningful since he formed his own architectural theory on the basis of what he translated; and indeed his critique of Gyeongseong buildings, however simple, was based on the theory. This research makes a critical analysis of Park’s functionalist theory from both the 1930s’ and present points of view and compares his commentaries on Gyeongseong architecture with those by Ko Yu-seop (1932) and Hong Yunsick (1937), illustrating how Korea perceived architecture and modernism in 1930s.
        4,600원
        18.
        2023.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Purpose: This study utilizes a phenomenological research method to understand the nature of role adaptation experience of PA nurses. Methods: This was a qualitative study that applied Colaizzi’s phenomenological research method to understand the nature of role adaptation experience of PA nurses. The study participants were thirteen PA nurses (three men and ten women) with over five years of experience. For data collection, individual in-depth interviews were conducted, each about 50 to 90 minutes long. Individual interviews were conducted once or twice. Colaizzi’s method was used to analyze data. Results: The result of this study had 11 clusters of themes and 4 major themes were derived from the analysis: “parallel lines of conflict,”“anxiety about unclear future,”“disorganization of identity,”and “my own way to learn about myself.”These four major themes are structured chronologically to the extent possible but are not mechanically segmented based on time. Conclusion: This study recognizes the seriousness of PA nurses’problems in the absence of research on PA nurses’role adaptation experience and recommends that appropriate research is necessary. Standardized work guidelines and positive awareness of the role of PA nurses are necessary and are supported by PA nurses to establish their position as professionals.
        4,000원
        20.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Tomatoes in greenhouse are a widely cultivated horticultural crop worldwide, accounting for high production and production value. When greenhouse ventilation is minimized during low temperature periods, CO2 enrichment is often used to increase tomato photosynthetic rate and yield. Plant-induced electrical signal (PIES) can be used as a technology to monitor changes in the biological response of crops due to environmental changes by using the principle of measuring the resistance value, or impedance, within the crop. This study was conducted to investigate the relationship between tomato growth data, vital response, and PIES resulting from CO2 enrichment in greenhouse tomatoes. The growth of tomato treated with CO2 enrichment in the morning was significantly better in all items except stem diameter compared to the control, and PIES values were also higher. The growth of tomato continuously applied with CO2 was better in the treatment groups than control, and there was no significant difference in chlorophyll fluorescence and photosynthesis. However, PIES and SPAD values were higher in the CO2 treatment group than control. CO2 enrichment have a direct relationship with PIES, growth increased, and transpiration increased due to the increased leaf area, resulting in increased water absorption, which appears to be reflected in PIES, which measures vascular impedance. Through this, this study suggests that PIES can be used to monitor crops due to environmental changes, and that PIES is a useful method for non-destructively and continuously monitoring changes of crops.
        4,000원
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