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        검색결과 445

        1.
        2025.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated the correlation between compound malodor and total hydrocarbons (THC) to evaluate the potential use of THC as a predictor of compound malodor. A total of 87 samples were analyzed from five target facilities: two petrochemical manufacturing facilities (A, B), a wastewater treatment facility (C), a recycled plastic injection molding facility (D), and a surfactant manufacturing facility (E). The correlation coefficients of compound malodor and THC for each facility were as follows: A: 0.6698, B: 0.8068, C: –0.2767, D: 0.2071, and E: 0.7695. The correlation coefficient for all facilities was 0.5634, indicating a weak correlation. The coefficients of determination for the regression analysis to predict the compound malodor for facilities A, B, and E were 0.4093, 0.6316, and 0.5695, respectively, which validated the results of the correlation analysis. These values improved to 0.8394, 0.6941, and 0.7476 in the multiple regression analysis with the VOC analysis results added as independent variables. Therefore, it is expected that THC measurement that considers the characteristics of the facility can be used to establish a systematic odor management plan.
        4,000원
        2.
        2024.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        출산에 관한 의사결정은 미시・거시차원의 여러 요인들이 복합적으로 작 용하여 단순하지 않다. 낮은 합계출산율 제고를 위한 다양한 노력이 오랫동 안 경주되고 있으나 젊은층의 출산패러다임의 변화에 기반을 둔 가치관, 성 평등변수를 반영한 합계출산율 영향요인을 분석한 국내연구가 필요하다. 본 연구는 합계출산율에 영향을 미치는 요인을 가치관, 경제적, 성평등 요인으 로 구분하여 통계분석을 실시하였다. 설명변수에서 자녀가치관, 남성의 육아 참여도, 성별가사분담률 등의 개선과 추가는 선행연구와 차별되는 점이다. 16개 광역시도의 2005-2022년 데이터를 패널화하여 Pool OLS, 고정효과 및 확률효과모형으로 회귀분석을 실시하였는데 분석결과는 다음과 같다. 첫 째, 자녀가치관은 서구적인 가치관이 아닌 결혼에 기반을 둔 자녀출산이라는 관점이 1% 유의수준에서 합계출산율에 정적 영향을 미쳤다. 둘째, 선행연구 와 달리 사교육비의 영향이 출산율에 즉각적으로 반영되지 않았으며, 0.1% 유의수준에서 아파트매매가격지수가 높을수록 합계출산율에 정적 영향을 미 쳤다. 셋째, 소득이 보장되지 않는 남성육아휴직은 합계출산율 감소와 연결 되며, 여성고용률과 합계출산율의 관계는 유의미하지 않아 선진국 모형과 다 르다는 것을 확인하였다.
        6,300원
        3.
        2024.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The MBR process, which uses membrane to separate solids instead of secondary clarifier, has the advantage of maintaining high MLSS (Mixed Liquor Suspended Solids) concentration in bioreactors. In this study, three MBR processes combined with chemical phosphorus removal facility were studied: the phase-isolated MBR process with one recirculation pump, the A2O MBR process with two recirculation pumps, and the MBR process without a oxygen depletion reactor with three recirculation pumps. 116 simulations by EQPS (Effluent Quality Prediction System) were performed, under same design influent characteristics and hydraulic retention time, to see the effects of recirculation ratio changes on effluent water quality. The final effluent limits for total nitrogen and phosphorus were set to as 10 ㎎/L or less and 0.2 ㎎/L or less, respectively. AlCl3 was fed at MBR effluent to make 0.2 ㎎/L of total phosphorus precisely by PI (Proportional-Integral) controller in EQPS. This study showed that the phase isolated MBR process (R1 600%) had the highest nitrogen removal efficiency, with a final effluent T-N concentration of 6.765 mg/L. However, the A2O MBR process (R1 400%, R2 100%) required the lowest AlCl3 flow of 0.742 m3/day, which is approximately 59.1% lower than the average AlCl3 flow of the phase-isolated MBR process. It also produced 4,835 kg/day of sludge, the lowest among the studying MBR processes. It seems that A2O MBR process is the most economic method to treat studying wastewater to meet final effluent nutrient limit targets. However, carbon neutrality must be considered to select the best process to treat studying wastewater and it will be presented later.
        4,500원
        4.
        2024.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        산화적 스트레스는 활성산소의 과도한 생성으로 인해 발생하며, 이는 만성퇴행성질환의 원인으로 알려져 있다. 본 연구에서는 식용 덖음 꽃차 8종 추출물의 폴리페놀 및 플라보노이드 함량, radical 소거 활성 측정을 통해 이들의 항산화 활성을 확인하고자 하였다. 8종의 식용 꽃차 에탄올 추출물 중에서 생강나무(Lindera obtusiloba, LO), 산수유(Cornus officinalis, CO) 및 카모마일(Matrecaria chamomilla) 꽃차 추출물의 총 폴리페놀 함량은 각각 20.21, 13.39, 12.39 mg gallic acid equivalent/g의 수치를 나타내었으며, 총 플라보노이드 함량은 LO, CO, 및 매화(Prunus mume) 꽃차 순으로 높은 수치를 나타내었다. 8종의 식용 꽃차 에탄올 추출물은 10, 25, 50, 100 μg/mL의 농도에서 2,2-diphenyl-1-picrylhydrazyl (DPPH) 및 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS+) 라디칼 소거 활성을 농도 의존적으로 증가시켰다. 특히, LO와 CO 꽃차 추출물은 다른 꽃차 추출물에 비해 우수한 DPPH 라디칼 소거 활성을 보였다. 또한 100 μg/mL 농도에서 CO, LO, 및 목련(Magnolia kobus) 꽃차 추출물의 ABTS+ 라디칼 소거 활성이 70% 이상의 수치를 나타내어 우수한 ABTS+ radical 소거 활성을 나타내었다. 본 연구 결과를 통해 식용 덖음 꽃차는 radical 소거 활성 및 폴리페놀과 플라보노이드를 함유함에 따라 항산화 활성을 나타냄을 알 수 있었으며, 특히 다른 꽃차 추출물에 비해 LO와 CO의 폴리페놀과 플라보노이드 함량 및 radical 소거능이 우수하여 항산화 기능성 소재로 활용될 수 있을 것으로 사료된다.
        4,000원
        5.
        2024.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study aims to examine total factor productivity (TFP) and its determinants in offshore fisheries under the worsening fishing environment and to propose policy improvement based on the estimation results. We identified a decline in TFP of offshore fisheries from 2012 to 2020 employing the global Malmquist productivity index (GMPI), with the primary cause being the regression of the production possibility frontier due to the reduction of fishery resources. Moreover, utilizing the system generalized method of moments (GMM), we found that the determinants, such as the cessation of operations in Japan’s EEZ, vessel age, fishing experience, and oil prices, contribute to a decrease in the TFP of offshore fisheries. Therefore, this study suggests implementing a total allowable catch (TAC)-centered fishery resource management policy, along with reducing loan interest rates and extending the repayment period for the vessel modernization project. Furthermore, it is necessary to improve the TFP of offshore fisheries by providing regular training for fishermen, implementing the tax-free petroleum stockpiling project, and developing alternative fishing grounds.
        4,900원
        6.
        2024.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study evaluates the potential of various coagulants to enhance the efficiency of total phosphorus removal facilities in a sewage treatment plant. After analyzing the existing water quality conditions of the sewage treatment plant, the coagulant of poly aluminium chloride was experimentally applied to measure its effectiveness. In this process, the use of poly aluminium chloride and polymers in various ratios was explored to identify the optimal combination of coagulants. The experimental results showed that the a coagulants combination demonstrated higher treatment efficiency compared to exclusive use of large amounts of poly aluminium chloride methods. Particularly, the appropriate combination of poly aluminium chloride and polymers played a significant role. The optimal coagulant combination derived from the experiments was applied in a micro flotation method of real sewage treatment plant to evaluate its effectiveness. This study presents a new methodology that can contribute to enhancing the efficiency of sewage treatment processes and reducing environmental pollution. This research is expected to make an important contribution to improving to phosphorus remove efficiency of similar wastewater treatment plant and reducing the ecological impact from using coagulants in the future.
        4,000원
        7.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 예술가가 작품을 구상하는 과정에서 그 아이디어를 최초로 구현한 통합적 노 트인 플럭서스의 총보를 중심으로, 예술가의 통합적 노트가 융합적 창작을 기획하는 예술가 의 파라큐레토리얼의 실천으로써 가지는 시의성을 제시하고자 한다. 이를 위해, 리하르트 바 그너의 ‘총체예술’부터 빈 분리파가 제시하는 ‘예술가사회’ 그리고 라즐로 모홀리 나기가 바 우하우스 극과 ‘총체극’에서 제안하는 동등한 협업관계까지 융합적 창작에 대한 태도와 방식 이 어떻게 확장되어왔는지 먼저 살펴본다. 이러한 협업에 대한 관계의 성향, 태도 등은 이후 1950-60년대 현대음악 작곡과 전위적 퍼포먼스에서 다양한 장르의 예술가들이 함께 활동 하는 과정을 중심으로 재조명할 수 있다. 특히, 플럭서스가 제시하는 느슨한 예술가 커뮤니 티와 인터미디어의 개념을 총체예술의 계보 안에서 고찰해본다. 그리고 이 개념을 바탕으로 플럭서스 예술가들의 구체적인 총보와 퍼포먼스 사례들에서 예술가들이 서로가 서로의 기획 에 어떻게 퍼포머의 역할을 수행하여 협업했는지 그 과정을 추적한다. 당시 작곡이나 각본, 드로잉과 같은 형식으로 작성된 예술가의 통합적 노트가 작품화 되는 과정은 여러 예술가들 의 협업을 필요로 했다. 이 연구는 오늘날 다원 예술에서 예술가들이 서로의 작품에서 다양 한 역할을 수행하는 과정 중, 고려해야할 협업의 태도에 대한 지침이 될 것을 기대한다.
        6,100원
        9.
        2024.04 구독 인증기관·개인회원 무료
        Rhaphidophoridae (Orthoptera: Ensifera), commonly known as cave crickets, are a wingless family and considered the most ancient lineage within Tettigoniidea. However, previous molecular phylogenetic studies and morphological hypotheses have shown inconsistencies. Although their fossils have been found in Baltic amber, their systematic placement remains unrevealed. This study reconstructed a comprehensive phylogeny integrating both extant and fossil lineages. Initially, we revealed relationships within extant lineages through molecular phylogenetics including all extant subfamilies for the first time. Subsequently, using a cladistic approach based on morphology, we confirmed the systematic position of fossil taxa †Protroglophilinae with a report of a new species. Integrating molecular and morphological phylogeney by total evidence tip-dating, we present the comprehensive phylogeny of Rhaphidophoridae considering both extant and fossil groups.
        10.
        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
        11.
        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
        12.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Dissolved organic matter (DOM) is a key component in the biogeochemical cycling in freshwater ecosystem. However, it has been rarely explored, particularly complex river watershed dominated by natural and anthropogenic sources, such as various effluent facility and livestock. The current research developed a new analytical method for TOC/TN (Total Organic Carbon/Total Nitrogen) stable isotope ratio, and distinguish DOM source using stable isotope value (δ13C-DOC) and spectroscopic indices (fluorescence index [FI] and biological index [BIX]). The TOC/TN-IR/MS analytical system was optimized and precision and accuracy were secured using two international standards (IAEA-600 Caffein, IAEA-CH-6 Sucrose). As a result of controlling the instrumental conditions to enable TOC stable isotope analysis even in low-concentration environmental samples (<1 mgC L-1), the minimum detection limit was improved. The 12 potential DOM source were collected from watershed, which includes top-soils, groundwater, plant group (fallen leaves, riparian plants, suspended algae) and effluent group (pig and cow livestock, agricultural land, urban, industry facility, swine facility and wastewater treatment facilities). As a result of comparing characteristics between 12 sources using spectroscopic indices and δ13C-DOC values, it were divided into four groups according to their characteristics as a respective DOM sources. The current study established the TOC/TN stable isotope analyses system for the first time in Korea, and found that spectroscopic indices and δ13C-DOC are very useful tool to trace the origin of organic matter in the aquatic environments through library database.
        4,000원
        13.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, a THC removal system was developed using an oxidation catalyst to solve the problems of the existing thermal oxidation methods, RTO and RCO. In addition, this system was applied to industrial sites to confirm the VOCs removal efficiency. As a result of testing to remove THC and VOCs by applying the reaction system for THC removal in industrial sites, the THC removal efficiency range is between 99.5% and 99.9%. The treatment efficiency of individual VOCs treated through this system was the lowest at 79.0% for methylethylketone and the highest at 91.3% for acetaldehyde, and the average treatment efficiency was about 85.4%. From these numbers, the performance was superior to the existing RTO and RCO systems that showed THC removal performance. This is due to the fact that the oxidation reaction of the oxidation catalyst is a very fast catalyst surface reaction, and the characteristics of the catalytic oxidation reaction are complete oxidation and oxidation reaction under rarefied conditions. In this study, the catalyst role in the reaction system for THC removal is to process THC simultaneously with the system heat source. This is believed to be because the reaction of the oxidation catalyst is a strongly exothermic reaction and can sufficiently provide the amount of heat necessary for the system. At the same time, an oxidation reaction that breaks the bonds of the THC component also occurs. This reaction is a strong exothermic reaction, which can help the system maintain a high temperature during the reaction, and is considered an effective system for processing high concentrations of THC in actual industrial sites where THC concentrations are high, as in this study.
        4,000원
        14.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper proposes an algorithm for the Unrelated Parallel Machine Scheduling Problem(UPMSP) without setup times, aiming to minimize total tardiness. As an NP-hard problem, the UPMSP is hard to get an optimal solution. Consequently, practical scenarios are solved by relying on operator's experiences or simple heuristic approaches. The proposed algorithm has adapted two methods: a policy network method, based on Transformer to compute the correlation between individual jobs and machines, and another method to train the network with a reinforcement learning algorithm based on the REINFORCE with Baseline algorithm. The proposed algorithm was evaluated on randomly generated problems and the results were compared with those obtained using CPLEX, as well as three scheduling algorithms. This paper confirms that the proposed algorithm outperforms the comparison algorithms, as evidenced by the test results.
        4,000원
        20.
        2023.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Some patients may not fully recover their daily activity capabilities even after the total hip replacement (THR), and may continue to experience functional limitations for up to a year after the procedure, according to reports. Objectives: The purpose of this study was to examine the effects of machine squat on muscle strength, balance and gait in patients after THR. Design: A randomized controlled trial. Methods: Thirty-three patients after THR were randomly allocated into slide (n=11), reformer (n=11), and control groups (n=11). Each group underwent their respective squat regimens for thirty minutes, seven times a week, for two weeks. Muscle strength changes were assessed using the manual muscle test (MMT), balance was evaluated using the Berg Balance Scale (BBS), and gait analysis was performed using the 10-meter walk test (10MWT). Results: Significant changes in hip flexor and abductor strength were observed in the slide and reformer groups within each group (P<.05). The reformer group showed significant changes in hip extensor strength (P<.05). Significant improvements in BBS were observed in all three groups (P<.05). There were significant changes in 10MWT in the slide and reformer groups (P<.05). A significant difference in hip extensor strength was found between the reformer and control groups after the intervention (P<.0167). Significant differences in BBS were observed between the slide and reformer groups and between the reformer and control groups after the intervention (P<.0167). Conclusion: Our findings suggest that machine squat regimens can be effective for early rehabilitation after THR, improving muscle strength, balance, and gait.
        4,000원
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