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        검색결과 452

        1.
        2025.01 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Fishways, particularly installed at the estuary, have a purpose to encourage fluent migration for migratory fishes, as well as amphidromous and even freshwater species. Not choosing the laborious traditional method of using traps, we assessed the efficiency of the two fishways installed at the west and east barrage of the Nakdong River estuarine barrage respectively, by analyzing the videos recorded through automatic monitoring system. We randomly selected 30 videos monthly at each fishways and identified what kind of fishes were using the fishways and categorised their behaviour such as size, time and whether they passed the monitoring system or not. As a result, a total 8 families 14 species were recorded by monitoring system, with the most dominance of Erythroculter erythropterus (Relative Abundance: 59.5%), followed by Micropterus salmoides (R.A: 19.9%) and Mugil cephalus (R.A: 9.9%). The monitoring system can capture passing fishes during night but the number of appearances of fish species at each hour of a day indicated significant diurnal activities (p<0.05). When fishes pass the monitoring system, approximately 70% of them passed through the monitoring device, while 17% of them showed fallback movement. Our finding indicates that species-specific characteristics of each fish are well represented through video monitoring method. In order to maximise advantages of using video monitoring, it is necessary to consider the installation point properly so that the monitoring system does not interfere with the movement of fish. Also, the utilisation of AI technology in the future is also necessary.
        4,300원
        2.
        2024.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 기업 디지털 트랜스포메이션(digital transformation) 교육의 효과성 분석을 위하여, K사 디 지털 트랜스포메이션 교육에 참여한 수료자 679명을 대상으로 2023년 11월 20일부터 11월 30일까지 설문 을 실시하였다. 설문은 학습자들의 나이, 직급 등 일반적인 특성을 포함하여, 개인특성으로 자기효능감, 학습 민첩성, 데이터 리터러시, 교육과정 특성으로 교육 만족도, 내용 이해도, 강사 전문성, 업무 관련성, 조직풍토 특성으로 전이기회, 상사지원, 그리고 현업적용도, 직무몰입, 직무성과에 대한 질문을 포함한 다. 주요 연구결과는 다음과 같다. 첫째, 일반적 특성에 따른 현업적용도 평균 차이 분석결과, 성별, 연령대, 직급, 수강영역에 따른 차이가 존재하지 않았지만, 디지털 트랜스포메이션 교육 참여 횟수, 교육 전/후 학습모임 참여 경험, 교육 전 파이썬 프로그램 활용 경험 수준에 따른 평균 차이가 통계적으로 유의미한 것으로 나타났다. 둘째, 개인특성, 교육과정 특성, 조직풍토가 현업적용도에 미치는 영향을 확인하기 위해 위계적 회귀분석을 실시한 결과, 개인특성 중에서는 자기효능감, 교육과정 특성에서는 내용 이해도, 조직 풍토에서는 전이 기회가 통계적으로 유의한 정적 영향을 미쳤으며, 영향력의 크기는 내용 이해도, 전이 기회, 자기효능감 순으로 큰 것으로 나타났다. 셋째, 현업적용도와 직무몰입, 직무성과와의 관계를 분석한 결과, 현업적용도는 직무몰입과 직무성과에 정적인 영향을 미치는 것으로 나타났으며, 현업적용도와 직무 성과와의 관계를 직무몰입이 완전 매개하는 것을 확인하였다. 이는 디지털 트랜스포메이션 교육 프로그 램에 참가한 학습자가 교육 내용에 대한 충분한 이해를 바탕으로 이를 현업에 적용하고, 직무에 몰입함으 로써 직무성과로 이어질 수 있다는 것을 의미한다. 넷째, 하위변인을 반영한 최적 모형 도출 결과, 개인특 성인 자기효능감은 교육과정 특성의 내용이해도와 조직풍토의 전이기회를 매개로 현업적용 노력과 실제 현업적용에 영향을 미쳤다. 특히, 현업적용 노력에는 내용이해도가 더 큰 영향을 미치고, 실제 현업적용에 는 전이기회가 더 큰 영향을 미친 것으로 나타났다. 이러한 연구결과를 바탕으로 후속연구 수행을 위한 시사점과 제도개선 방안을 제시하였다.
        5,500원
        6.
        2024.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Endemic species are defined as taxa that naturally inhabit and grow within a specific area. Because they easily face regional extinction, continuous management is required. In this study, stable isotope analysis, length-weight relationships (LWRs), and condition factor (K) estimation were applied to oily bitterling Acheilognathus koreensis inhabiting three representative rivers including the Geum River basin, Seomjin River basin, and Tamjin River basin to compare ecological property and related biological conditions. Based on the corrected isotope value to account for difference in carbon isotope ratio (δ13C) of POM, Δδ13CA.koreensis-POM, estimated isotope niche areas of A. koreensis between Geum and Tamjin River populations were highly overlapped while those of the Seomjin River population were discriminated from other habitats, indicating differences in major diet sources among habitats. In addition, LWRs for the Seomjin River population showed a good growth with a b value of 3.155 compared to Geum and Tamjin River populations which showed relatively low growth rates of 2.888 and 2.968, respectively. Fluctuation of the K value of the A. koreensis tended to decrease with growth in the Geum River while that of the Seomjin River population exhibited the highest increasing trend. This study confirmed differences in diet resources among habitats for A. koreensis, which resulted growth and fatness variations for each population. Our results can be used as basic information for effective conservation and management strategies of A. koreensis populations.
        4,000원
        7.
        2024.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Broccoli and cabbage are known to have antioxidant, cholesterol-lowering, and anticancer effects due to their high bioactive component levels. This study applied 70% ethanol and hydrothermal extraction to separate bioactive components from broccoli and cabbage. 30oBrix extracts were freeze-dried and then diluted in various concentrations with distilled water for analysis. Total polyphenol contents, DPPH radical scavenging activity, ABTS radical scavenging activity, ferric ion reducing antioxidant power, and hydrogen peroxide scavenging activity were analyzed. The diverse antioxidant assays, except DPPH radical scavenging activity, showed that hydrothermal extracts had significantly higher activity than the 70% ethanol extracts (p<0.05). In this study, it suggested that hydrothermal extraction is relatively effective in producing broccoli and cabbage extracts. Moreover, hydrothermal extraction conditions could be low-cost and environmentally friendly.
        4,000원
        10.
        2024.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study aimed to examine the morphological characteristics and variation in main traits by comparing the growth of individuals of Ecklonia cava Kjellman (Laminariales, Phaeophyceae) under an aquaculture environment. This survey was conducted from April 2018 to November 2019 at the aquafarm in Jindo-gun, Jeollanam-do (South coast of Korea). To classify the morphology of individuals in the aquaculture farm of E. cava, we investigated fourteen morphological characteristics and calculated four ratios between the measured values. Juvenile individuals showed a simple or oblong lanceolate, and at 3-4 months, a short stipe and holdfast developed, along with a bladelet that developed into the secondary blade form. At 5-7 months, secondary blades were found to develop irregularly on the primary blade. At 8-10 months, the primary blade expanded and secondary blades elongated. At 11-12 months, the secondary blades became oblong. At 13-14 months, the thallus area expanded. At 15-16 months, tertiary blades were formed, the thallus became more complex, the stipe thickened, and the holdfast widened. At 17-18 months, secondary blades clearly developed along with lobes. At 19-20 months, tertiary blades developed and became similar to mature natural blades. In the principal component analysis (PCA), the monthly population of the first year (Q1) and that of the second year (Q2) of the cultured population were divided along PC1, which is related to secondary blade morphological characteristics and the holdfast width. Q2 and natural populations are distributed in descending order of volume in Jeju (J), East Coast (E), and South Coast (S) along PC2, which is related to primary blade and stipe morphological characteristics. The results of this study were judged to offer important criteria for the development of different varieties of E. cava.
        4,800원
        11.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : This study aims to propose drone-command standard operating procedure (SOP) guidelines and Analyze their potential application to increase the use and utility of drones in urban disaster situations. Although the effectiveness and efficiency of obtaining disaster-situation information through drones have been verified by previous studies and practical experience, a survey of actual drone usability indicated a utilization rate of only approximately 4.13%. METHODS : To provide guidance for improving drone command SOPs, prior research and relevant literature were reviewed to identify commonalities between disaster-response command and control and drone use. A sample of 73 active-duty firefighters, including incident commanders (ICs) and drone pilots, were surveyed and interviewed. The data were analyzed and categorized to establish the reasons why drones are not actively used in urban disaster-response procedures. RESULTS : The primary reasons identified for not actively utilizing drones in urban disaster areas were the lack of a drone command and control system and the lack of clear criteria for when to use drones in disaster situations. In addition, many problems were found in drone-operation procedures, including emergency flight approval, securing takeoff and landing sites, and accident burden due to urban flight obstacles. To address the issues identified, standards were proposed for the type, size, and scope of urban disasters requiring drone response; for accident-prevention on basic missions and through flight safety procedures; and for installing a video transmission and reception system to easily share drone video information with ICs. CONCLUSIONS : Application of the drone-command SOP guidelines to actual urban disaster situations by disaster type will help to improve the efficiency of information acquisition and flight safety. This is expected to enable increased drone utilization. In future, extension of the research reported in this paper beyond the Seoul metropolitan area via additional follow-up studies has the potential to establish applicability of the proposed SOP guidelines to a wide variety of environments and organizational characteristics.
        4,000원
        13.
        2023.08 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        본 연구는 아그니와 효소의 종류와 기능을 고찰하고 활성화를 위한 섭생 요법에 대해 소개하였다. 음식 소화에 있어서 아그니와 효소의 불균형은 인체의 신진대사에 악영향을 주어 질병에 노출을 증 가시킨다. 섭생 요법은 소화와 대사를 촉진하고, 독소를 제거하고, 면역력을 높이는 기초이며 건강하 기 위한 중요한 요법이다. 아유르베다 의학의 섭생 요법은 개인의 도샤(doṣa)에 따라 다른 효과를 나 타낼 수 있으며, 일상생활의 규칙성, 식사 시간이나 양, 조리방법 등을 고려해 도샤에 맞는 음식을 섭 취해야 한다. 현대 의학 효소는 화학적인 분자이며 과학적인 근거를 바탕으로 수치화되고 정밀화되고 있다. 효소 활성화를 통해 음식의 칼로리와 영양소가 인체에 흡수되는 정도를 파악할 수 있고 다양한 조리방법으로 흡수 효율을 높이기 위해 노력하고 있다. 또한 세계보건기구(WHO)는 건강한 식사와 생 활 방식을 통해 만성 질환과 감염병을 예방하고 건강을 증진하기 위해 섭생 요법을 권장하고 있다. 이 논문을 통해 우리는 아유르베다 의학과 현대 의학이 공통적으로 강조하고 있는 섭생 요법이 건강 을 유지하는 기본임을 알 수 있을 것이다.
        4,600원
        14.
        2022.12 구독 인증기관 무료, 개인회원 유료
        미역(Undaria pinnatifida) 포자를 사용한 생태독성 시험법은 연중 상시 이용하기에 어렵다. 미역 의 암배우체는 실험실에서 배양할 수 있기 때문에, 포자의 단점을 보완하고 상시 생태독성 시 험에 사용할 수 있다. 따라서 미역의 암배우체를 생태독성 시험에 활용하기 위해 다양한 환경 조건에 노출된 미역의 암배우체 생존율과 상대성장률의 변화를 분석하였다. 미역 암배우체는 염분(5~40 psu), 온도(5~30℃), pH (2~10), 광량(0~120 μmol photon m-2 s-1)에 노출되었다. 암배 우체의 생존율은 최고 평균값을 기준으로 온도 20℃, 염분 27.5 psu, pH 8, 광량 30 μmol photon m-2 s-1에서 가장 높았다. 상대성장률은 최고 평균값을 기준으로 온도 15℃, 염문 35 psu, pH 9, 광량 60 μmol photon m-2 s-1에서 가장 높았다. 본 연구결과를 통해 미역 암배우체의 생존율과 상대성장률을 활용하여 연안환경을 상시 신속하게 평가하기 위한 효율적인 방법으로 활용이 기대된다.
        4,000원
        15.
        2022.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Anthropogenic disturbances on freshwater ecosystem are known to degrade biodiversity, especially on fish assemblage. In this study, we have conducted fish surveys to identify impact of a bridge construction on fish assemblages. A total of eight study sites were surveyed in the Danjang and the Dong Stream in southern part of South Korea from June to November in 2021. The fish samplings were carried out five times, using cast-nets (10×10 mm mesh size), scoop-nets (4×4 mm, 5×5 mm mesh size), set-nets (10×10 mm mesh size), and fish traps (3×3 mm mesh size), along with the Stream/River Ecosystem Survey and Health Assessment by the Ministry of Environment of Korea and basic water quality measurement. Also, we applied the species diversity index and length-weight relationship regressions on certain species to identify interspecific growth rate differences in accordance with study sites. As a result, a total of 782 individuals, 23 species and 10 families were collected. The dominant species was Zacco Koreanus and relative abundance was 50.89%. When applying the length-weight relationship regressions on certain species, the ‘b’ value for Z. Koreanus was lower at the downstream points than at the upstream points of the construction site. In addition, when comparing to the results of the past survey, relative density of demersal fish at the upstream and downstream points decreased from 26% to 1.4%, and from 18% to 6.3%, respectively. In conclusion, it is considered that bridge construction negatively affects the habitat of fishes, especially on demersal fishes. Therefore, appropriate conservation efforts such as installation of silt protector and sand sedimentation pond are needed to alleviate the disturbance in habitat such as occurrence of turbidity and destruction of micro-habitats.
        4,500원
        16.
        2022.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study demonstrates the effect of the compaction pressure on the microstructure and properties of pressureless-sintered W bodies. W powders are synthesized by ultrasonic spray pyrolysis and hydrogen reduction using ammonium metatungstate hydrate as a precursor. Microstructural investigation reveals that a spherical powder in the form of agglomerated nanosized W particles is successfully synthesized. The W powder synthesized by ultrasonic spray pyrolysis exhibits a relative density of approximately 94% regardless of the compaction pressure, whereas the commercial powder exhibits a relative density of 64% under the same sintering conditions. This change in the relative density of the sintered compact can be explained by the difference in the sizes of the raw powder and the densities of the compacted green body. The grain size increases as the compaction pressure increases, and the sintered compact uniaxially pressed to 50 MPa and then isostatically pressed to 300 MPa exhibits a size of 0.71 m. The Vickers hardness of the sintered W exhibits a high value of 4.7 GPa, mainly due to grain refinement.
        4,000원
        18.
        2022.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated the seismic performance of reinforced concrete (RC) wall-slab frames with masonry infills. Four RC wall-slab frames with or without masonry infill were tested under cyclic loading. The RC frames were composed of in-plane and out-of-plane walls and top and bottom slabs. For masonry infill walls, cement bricks were stacked applying mortar paste only at the bed joints, and, at the top, a gap of 50 mm was intentionally left between the masonry wall and top RC slab. Both sides of the masonry walls were finished by applying ordinary or fiber-reinforced mortars. The tests showed that despite the gap on top of the masonry walls, the strength and stiffness of the infilled frames were significantly increased and were different depending on the direction of loading and the finishing mortars. During repeated loading, the masonry walls underwent horizontal and diagonal cracking and corner crushing/spalling, showing a rocking mode inside the RC wall-slab frame. Interestingly, this rocking mode delayed loss of strength, and as a result, the ductility of the infilled frames increased to the same level as the bare frame. The interaction of masonry infill and adjacent RC walls, depending on the direction of loading, was further investigated based on test observations.
        4,200원
        19.
        2022.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The synthesis of porous W by freeze-casting and vacuum drying is investigated. Ball-milled WO3 powders and tert-butyl alcohol were used as the starting materials. The tert-butyl alcohol slurry is frozen at –25oC and dried under vacuum at –25 and –10oC. The dried bodies are hydrogen-reduced at 800oC and sintered at 1000oC. The XRD analysis shows that WO3 is completely reduced to W without any reaction phases. SEM observations reveal that the struts and pores aligned in the tert-butyl alcohol growth direction, and the change in the powder content and drying temperature affects the pore structure. Furthermore, the struts of the porous body fabricated under vacuum are thinner than those fabricated under atmospheric pressure. This behavior is explained by the growth mechanism of tert-butyl alcohol and rearrangement of the powders during solidification. These results suggest that the pore structure of a porous body can be controlled by the powder content, drying temperature, and pressure.
        4,000원
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