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        검색결과 114

        1.
        2025.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        전 세계적으로 생물다양성을 보호하기 위한 방법으로 보호지역을 지정하고 있지만, 보호지역에 대한 관리 부족으로 효과성을 평가하기 어렵다. 보호지역 효과성 평가를 위해 다양한 지표들을 이용하여 평가하고 있다. 그 중 토지피복 변화 분석은 경제적이고 장기적인 변화 파악이 가능하며, 공간적 제한이 상대적으로 적어 다양한 대상지에서 활용할 수 있다는 장점이 있다. 본 연구에서는 토지피복 변화를 이용하여 야생생물 보호구역의 효과성 평가를 목적으로 한다. 보호지역 내부와 외부, 타 보호지역과의 중복지정 여부, 지정 시기에 따라 과거 자연지역이 농업지역 또는 시가화건조지 역으로 변화한 비율을 분석하였다. 연구 결과로 첫째, 보호지역 내부에서는 보호 효과가 있지만, 외부에서는 개발압력이 있음을 알 수 있다. 둘째, 타 보호지역과 중복된 보호지역일수록 효과가 있음을 알 수 있다. 셋째, 지정 시기가 오래된 보호지역일수록 시간이 지남에 따라 토지피복 변화가 줄어들어 지속적인 효과가 있음을 알 수 있다. 본 연구는 경제적이 고 장기적 변화 파악이 가능한 토지피복을 이용하여 보호지역의 효과성을 정량적으로 평가했다는 점에 의의가 있다. 토지피복은 끊임없이 변화할 것이며, 드론과 같은 첨단장비를 이용하여 실시간 모니터링을 한다면 보호지역의 효과와 압력을 더욱 신속하고 정밀하게 평가할 수 있을 것이다.
        4,200원
        2.
        2025.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The intensity of typhoons is increasing due to the effects of global warming. These typhoons pass through the coast of Korea on an average of two to three times a year, causing a lot of damages. The harbor shelters for avoiding typhoons are congested with large and small vessels, so the distance between vessels is short, the veered out anchor chain is long, and there is a risk of collision due to dragging anchor caused by powerful winds. Therefore, this study aimed to quantitatively identify the degree of influence of external force factors on the experimental vessel during anchoring, and to provide basic data for setting the critical point of tension that can cause dragging anchor. The range of outlier of tension observed in the experimental vessel was -0.90 to 4.60 tons, and the ratio of outlier was approximately 5.07%. As a result of analyzing 184,008 samples of external force corresponding to this, a weak negative linear relationship was shown in the correlation between tension and external force for the current and wind direction whereas a positive correlation was shown for wind speed and current velocity. In this study, the effects of external force during anchoring on tension were in the order of wind speed, current velocity, current direction, and wind direction, and the ratios were 85.46%, 6.28%, 4.79%, and 3.47%, respectively. In future studies, we plan to quantitatively understand the relationship between holding power and tension indicated by the tension meter to determine the tension value that becomes the critical point of the dragging anchor.
        4,300원
        3.
        2024.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study aimed to analyze the behavioral changes and stress responses of cultured leather carp (Cyprinus carpio nudus) for repeated noise exposure. The acoustic stimulus was composed of twenty sets of one second duration noise with an average noise of 147 dB, which was repeated every five minutes. The behavioral changes of the fish were analyzed immediately after noise exposure, three hours, six hours, twelve hours, 24 hours, and 48 hours later. The stress hormone response was also analyzed and compared through blood collection. It was confirmed that the fish were significantly affected by the noise stimulus and unable to be free or adapt to it untill the end of the experiment. The cortisol concentration was also the highest at 38.2 ug/dL after six hours; the glucose concentration did not decrease over time, indicating that stress was maintained and had a significant effect.
        4,000원
        4.
        2024.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Strong ground motions at specific sites can cause severe damage to structures. Understanding the influence of site characteristics on the dynamic response of structures is crucial for evaluating their seismic performance and mitigating the potential damage caused by site effects. This study investigates the impact of the average shear wave velocity, as a site characteristic, on the seismic response of low-to-medium-rise reinforced concrete buildings. To explore them, one-dimensional soil column models were generated using shear wave velocity profile from California, and nonlinear site response analyses were performed using bedrock motions. Nonlinear dynamic structural analyses were conducted for reinforced concrete moment-resisting frame models based on the regional information. The effect of shear wave velocity on the structural response and surface ground motions was examined. The results showed that strong ground motions tend to exhibit higher damping on softer soils, reducing their intensity, while on stiffer soils, the ground motion intensity tends to amplify. Consequently, the structural response tended to increase on stiffer soils compared to softer soils.
        4,000원
        5.
        2024.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A variation of fish assemblage in the coastal waters of Sagye-ri, southern Jeju Island was determined using samples collected by trammel net from 2012 to 2022. The total fish species caught by trammel net were identified 88 species, 46 families, 12 orders, and the number of appearance and biomass were 3,479 individuals and 883.6 kg. The annual variation of species was the highest in 2013 at 46 species and the lowest in 2021 at 30 species. The seasonal variation of species was higher in summer at 67 species and lower in winter, autumn at 47 species. The annual diversity index, evenness index, and richness index were appeared 2.42-3.00, 0.69-0.78 and 5.18-7.24 at each years. The dominance index appeared highest in 2013 and the lowest in 2018. Cluster analysis based on the number of individuals of fish was classified into two groups at the dissimilarity level of 57%, and results of SIMPROF analysis revealed significant differences in community structure among the two groups. The subtropical fishes were identified a total of 42 species (47.7%) and the number of species was higher in 2013 at 25 (54.3%) species and lower in 2018 and 2021 at each 17 (54.8~56.7%) species. The dominant species of subtropical fishes were appeared rabbit fish (Siganus fuscescens), scarbreast tuskfish (Choerodon azurio), bluestriped angelfish (Chaetodontoplus septentrionalis), balloon fish (Diodon holocanthus), and flag fish (Goniistius zonatus) at study sites.
        4,600원
        10.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In order to present a predictive drift model, Jeju National University's training ship was tested for about 11 hours and 40 minutes, and 81 samples that selected one of the entire samples at ten-minute intervals were subjected to regression analysis after verifying outliers and influence points. In the outlier and influence point analysis, although there is a part where the wind direction exceeds 1 in the DFBETAS (difference in Betas) value, the CV (cumulative variable) value is 6%, close to 1. Therefore, it was judged that there would be no problem in conducting multiple regression analyses on samples. The standard regression coefficient showed how much current and wind affect the dependent variable. It showed that current speed and direction were the most important variables for drift speed and direction, with values of 47.1% and 58.1%, respectively. The analysis showed that the statistical values indicated the fit of the model at the significance level of 0.05 for multiple regression analysis. The multiple correlation coefficients indicating the degree of influence on the dependent variable were 83.2% and 89.0%, respectively. The determination of coefficients were 69.3% and 79.3%, and the adjusted determination of coefficients were 67.6% and 78.3%, respectively. In this study, a more quantitative prediction model will be presented because it is performed after identifying outliers and influence points of sample data before multiple regression analysis. Therefore, many studies will be active in the future by combining them.
        4,600원
        11.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The towing distance, which is speed over the ground, and the water flow quantity, which is speed through the water, were used when estimating the amount of Metapenaeus joyneri resources that rose to the surface at night using the swept area method in order to compare and analyze the difference. It was conducted using a shrimp dredge, trial fishing gear for catching Metapenaeus joyneri. Catch during the entire survey period was 188.9 kg. Monthly catch ranged from 3.1 to 109.2 kg, highest in June and lowest in September. The swept volume calculated using the speed over the ground was about 13% higher than using the speed through the water. Metapenaeus joyneri resources estimated using the towing distance ranged from 320.1 to 14,649.8 kg. Resources estimated using the water flow quantity ranged from 278.5 to 12,886.3 kg. Therefore, the amount of Metapenaeus joyneri resources estimated using the speed over the ground was about 14% higher than the method using the speed through the water, indicating that the amount of resources was overestimated.
        4,000원
        12.
        2023.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Long term variations of fish assemblage in the coastal waters of Bukchon-ri were determined using samples collected by trammel net from 2012 to 2022. Water temperature increased by 0.4℃ in 2022 that was less then 2012. During the survey period, a total of 95 species (53 families and 15 orders) of fishes were identified, Scorpaeniformes (five families and 22 species) and Perciformes (25 families and 39 species) accounted for 73% of the total number. The number of species was higher in summer than winter, showing a peak in summer at 66 species and lower in winter and autumn at 45 species. The number of individuals and the biomass peaked in summer at 1,238 individuals and 280.1 kg, and were the lowest in autumn at 597 individuals and 155.4 kg. The annual diversity index, evenness index and richness index were appeared 2.11-2.80, 0.64-0.80 and 4.70-7.34 at each years. The dominance index were appeared highest in 2014 while 2021 were appeared the lowest in 2017. The subtropical fishes were identified total of 38 species (40.0%) and the number of species was higher in 2022 at 22 (52.4%) species and lower in 2015-2017 at each 10 (31.3-37.0%) species. The dominant species of subtropical fishes were appeared rabbit fish (Siganus fuscescens), boxfish (Ostracion immaculatus), smallscale blackfish (Girella melanichthys), flag fish (Goniistius zonatus), stripey (Microcanthus strigatus), rock porgy (Oplegnathus punctatus), and bluestriped angelfish (Chaetodontoplus septentrionalis) in study sites.
        4,600원
        13.
        2023.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Although the abundance of Metapenaeus joyneri resources with high commercial value was recently confirmed in the outer waters of Gomso Bay, located between Buan-gun and Gochang-gun, Jeollabuk-do, Metapenaeus joyneri resources have not been efficiently utilized due to the absence of fishing gears and methods for a selective Metapenaeus joyneri capture. Therefore, in this study, we adopted shrimp dredge as a trial fishing gear for the Metapenaeus joyneri capture, and analyzed the species composition and cluster community structure of aquatic organisms caught by the shrimp dredge, from May to September 2021 at the coastal waters of Gochang-gun, Jeollabuk-do. During the experimental period, 28 types of marine species of 29,190 individuals and 250,136 g of total biomass were caught. Among them, the population of Metapenaeus joyneri, the target species, dominated by 80.7%, followed by Thrysa chefuensis with 7.1%, and Leiognathus nuchalis with 6.0%, confirming that the fishing ratio of Metapenaeus joyneri was the highest among all species.
        4,000원
        14.
        2023.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The swimming behavior of pacific bluefin tuna (Thunnus orientalis) in the offshore sea cage of the brass fishing net was observed and analyzed by imaging sonar techniques. The cultured fish spent most of the time swimming a circular path along the circular cage wall and continued to swim only clockwise direction without completely changing the swimming direction during the 23-hour observation time. In addition, changed swimming behaviors were divided into four categories: (a) the behavior of a large group temporarily swimming in the opposite (counter clockwise) direction, (b) the behavior of a small group temporarily swimming in a small circular path, (c) the behavior swimming small circular path in the center of the cage, and (d) the behavior of a large group swimming across the center of the cage. The maximum swimming speed of the cultured fish was from 3.5 to 3.8 TL/s, the mode was from 1.2 to 1.4 TL/s and the swimming speed during the day time was faster than at night time. It was confirmed the cultured fish swam not only on the surface but also near the bottom net of the cage during the day, but swam mainly at the upper part of the cage at night.
        4,000원
        18.
        2023.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper is the result of a comparative analysis of crew members' workloads using the EMG and OWAS methods according to the fishing process before and after the improvement of the operating system of the experimental vessel, with the aim of improving operational efficiency and safety work of coastal improved stow net fishing vessels. The target crew members were three people with at least five years of experience on board the same fishing vessel as the experimental vessel. After improving the operating system, such as installing a power block crane and two capstans, change the location of the ball-roller, the time required for setting and hauling work decreased (p < .01), and the evaluation results by OWAS showed that the overall workload for setting and hauling net work decreased. The results of muscle activity analysis showed a decrease in lashing anchor work (p < .01) in the case of hauling net and in anchor dropping work in the case of setting net (p < .001). It is judged that the use of ball rollers in net handling has been reduced; consequently, work safety has been improved.
        4,200원
        19.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In spite of lab safety act for over 10 years, over 100 safety accidents in the laboratory have been constantly occurring. The ideal safety management system is to prevent accidents by differential classifying and managing laboratory regulatory materials according to the risk level. In order to approach this system, in-depth interviews with safety managers were first conducted to identify the current status of safety management in domestic university laboratories. And then through comparative analysis of safety management systems in domestic and foreign laboratories, a new regulatory substance classification standard based on the analysis of the hazards and the classification of risk grades, and a safety management system are proposed. From this study, it will contribute to the creation of a safe laboratory environment by differential classification and management laboratory regulatory materials based on the risk level.
        4,000원
        20.
        2022.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In general, a high tension on the anchor and chain is placed when a ship at anchor is subjected to heavy weather. Mariners have to pay attention to whether dragging anchor occurs to keep the safety of the ship at anchorage since it is difficult to maintain the stable motion of ship and it causes collisions with other ships nearby. In this paper, the ship motion against the external forces was shown to obtain the fundamental data about characteristic of holding power due to nature of seabed at anchor, so practical trials were carried out in rocky area and muddy area using a trial ship around coastal area of South Korea. In muddy seabed, holding power showed reasonable tension values depending on the distance from anchor position of continuing swing motions of a ship corresponding to wind force. Meanwhile in rocky seabed, tension values on the chain appeared very high occasionally regardless of the distance from the anchor position and seemed to exceed its holding power to be the breaking strain of the chain although weather was not in a severe condition. Therefore, some of the cables laid on the seabed were presumed to be caught in a crack on the rock. It is assumed that even a small amount of external force may cause the chain to break in a moment in rocky seabed. Additionally, wind and current forces had a somewhat contradictory effect on holding power of the ship between them.
        4,200원
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