• Title/Summary/Keyword: 해양정보

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Identifying Yellow Sand from the Ocean Color Sensor SeaWIFS Measurements (해색 센서 SeaWiFS 관측을 이용한 황사 판독)

  • 손병주;황석규
    • Korean Journal of Remote Sensing
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    • v.14 no.4
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    • pp.366-375
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    • 1998
  • Optical characteristics of the yellow sand and their influences on the ocean color remote sensing has been studied using ocean color sensor SeaWiFS measurements. Two cases of April 18 and April 25, 1998, representing yellow sand and background aerosol, are selected for emphasizing the impact of high aerosol concentration on the ocean color remote sensing. It was shown that NASA's standard atmospheric correction algorithm treats yellow sand area as either too high radiance or cloud area, in which ocean color information is not generated. Optical thickness of yellow sand arrived over the East Asian sea waters in April 18 indicates that there are two groups loaded with relatively homogeneous yellow sand, i.e.: heavy yellow sand area with optical thickness peak around 0.8 and mild area with about 0.4, which are consistent with ground observations. The movement of the yellow sand area obtained from surface weather maps and backward trajectory analysis manifest the notion that the weak yellow sand area was originated from the outer region of the dust storm. It is also noted that high optical thickness associated with the yellow sand is significantly different from what we may observe from background aerosol, which is about 0.2. These characteristics allow us to determine the yellow sand area with an aid of atmospheric correction parameter. Results indicate that the yellow sand area can be determined by applying the features revealed in scattergrams of atmospheric correction parameter and optical thickness.

Study of Groundwater Recharge Rate Change by Using Groundwater Level and GRACE Data in Korea (지하수위와 GRACE 자료를 이용한 국내 지하수 함양량 변화 연구)

  • Jeon, Hang-Tak;Hamm, Se-Yeong;Jo, Young-Heon;Kim, Jinsoo;Park, Soyoung;Cheong, Jae-Yeol
    • The Journal of Engineering Geology
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    • v.29 no.3
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    • pp.265-277
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    • 2019
  • Changes in the amount, intensity, frequency, and type of precipitation, in conjunction with global warming and climate change, critically impact groundwater recharge and associated groundwater level fluctuations. Monthly gravity levels by the Gravity Recovery and Climate Experiment (GRACE) are acquired to monitor total water storage changes at regional and global scales. However, there are inherent difficulties in quantitatively relating the GRACE observations to groundwater level data due to the difficulties in spatially representing groundwater levels. Here three local interpolation methods (kriging, inverse distance weighted, and natural neighbor) were implemented to estimate the areal distribution of groundwater recharge changes in South Korea during the 2002-2016 period. The interpolated monthly groundwater recharge changes are compared with the GRACE-derived groundwater storage changes. There is a weak decrease in the groundwater recharge changes over time in both the GRACE observations and groundwater measurements, with the rate of groundwater recharge change exhibiting mean and median values of -0.01 and -0.02 cm/month, respectively.

Application and Utilization of Environmental DNA Technology for Biodiversity in Water Ecosystems (수생태계 생물다양성 연구를 위한 환경유전자(environmental DNA) 기술의 적용과 활용)

  • Kwak, Ihn-Sil;Park, Young-Seuk;Chang, Kwang-Hyeon
    • Korean Journal of Ecology and Environment
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    • v.54 no.3
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    • pp.151-155
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    • 2021
  • The application of environmental DNA in the domestic ecosystem is also accelerating, but the processing and analysis of the produced data is limited, and doubts are raised about the reliability of the analyzed and produced biological taxa identification data, and the sample medium (target sample, water, air, sediment, Gastric contents, feces, etc.) and quantification and improvement of analysis methods are also needed. Therefore, in order to secure the reliability and accuracy of biodiversity research using the environmental DNA of the domestic ecosystem, it is a process of actively using the database accumulated through ecological taxonomy and undergoing verification procedures, and experts verifying the resolution of the data increased by gene sequence analysis. This is absolutely necessary. Environmental DNA research cannot be solved only by applying molecular biology technology, and interdisciplinary research cooperation such as ecology-taxa identification-genetics-informatics is important to secure the reliability of the produced data, and researchers dealing with various media can approach it together. It is an area in desperate need of an information sharing platform that can do this, and the speed of development will proceed rapidly, and the accumulated data is expected to grow as big data within a few years.

Habitat Type Classification System of Korean National Parks (국립공원 서식지 유형 분류 체계 구축)

  • Kim, Jeong Eun;Rho, Paik Ho;Lee, Jung Yun;Cho, Hyung Jin;Jin, Seung Nam;Choi, Jin Woo;Myeong, Hyeon Ho
    • Ecology and Resilient Infrastructure
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    • v.8 no.2
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    • pp.97-111
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    • 2021
  • This study was conducted to develop a habitat type classification system and its map based on the ecological characteristics of species, spatial type, vegetation, topography, and geological conditions preferred by species. To evaluate the relationships between species and their habitats in Korean national parks, we prepared a classification standard table for systematic classification of habitat types. This classification system divides habitats into 6 low-level and 59 mid-level ecological classes based on habitat structure. The mid-level system divided forest ecosystems into 20 subtypes, stream and wetland ecosystems into 8 types, coastal ecosystems into 7 types, arable land into 6 types, development land into 9 types, and 1 type of marine ecosystem. A habitat classification map was drawn utilizing square images, detailed vegetation maps, and forest stand maps, based on the above habitat classification system, and it covered 1,461 plots spanning 21 national parks. The habitat classification system and survey protocol, which consider domestic habitat conditions, should be further developed and applied to habitat assessment, to enhance the utility of this study.

The Effect of Teaching Behavior Styles of Fisheries & Maritime High School Teacher on Students' Satisfaction in Major Subject Classes (수산·해운계열 고등학교 교사의 교수행동유형이 학생의 전공교과 수업만족도에 미치는 영향)

  • Cho, Jin-Ho;Choi, Young-Sun
    • Journal of vocational education research
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    • v.37 no.2
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    • pp.129-143
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    • 2018
  • The purpose of this study was to analyze how teaching behavior styles of fisheries & maritime high school teacher on students' satisfaction in major subject classes. A survey was conducted for high school students from fisheries & maritime high school. The results were as followed. First, there is a statistically significant correlation between fisheries & maritime high school teacher's teaching behavior styles and student's classes satisfaction. In other words, teaching behavior styles should be different according to the individual differences of students' learning. Second, fisheries & maritime high school teacher's teaching behavior styles has some significant influence on student's classes satisfaction. Diversity Teaching behaviors had a statistically significant effect on content satisfaction. Interaction teaching behavior, diversity teaching behavior style, and individualized teaching behavior style had a statistically significant effect on method satisfaction. For the evaluation satisfaction, there was a significant statistically significant effect of clarity on teaching behavior styles and diversity teaching behavior type. It is necessary to improve the content satisfaction of the students through the application of the teaching method considering the difference of understanding of the contents of each student.

A Study on Stabilization of Underwater TAS Winch System Deploy/Recover Operation Performance (수중용 TAS윈치 전개/회수 성능 안정화 방안에 관한 연구)

  • Chang, Ho-Seong;Cho, Kyu-Lyong;Hwang, Jae-Gyo;Lee, Sang-Yong;Kim, Yong-Tae
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.6
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    • pp.472-482
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    • 2019
  • This paper describes the stabilization of underwater TAS winch system Deploy/Recover operation performance. TAS winch installed on the stern of submarine performs to deploy/recover sensor, towing cable and rope tail which is deployed from the stern and separated from submarine itself. Also TAS winch provides transmission path of power to the sensor and data transmitting/receiving path which data are acquired from underwater environment like sound, depth and temperature. At the step of TAS winch evaluation test, sporadic standstill and rotating speed oscillation phenomenon were occurred. Winch motor provides the available torque to deploy/recover TAS and root cause analysis to the winch motor was done to find exact reason to sporadic malfunction. When winch motor was disassembled, eccentricity of rotor, slip-ring and the other composition part for winch motor were found. These might cause magnetic field distortion. To make TAS winch system more stable and block magnetic field distortion, this paper suggests methods to enhance fixing status installed in winch motor. For reliable data acquisition for TAS winch operation, the deploy/recover function of the improved type of TAS winch was verified in LBTS making similar condition with sea status. At the end of stage, improved type of TAS winch was tested on some functions not only deploy/recover function, but sustainability of TAS operation on specific velocity, steering angle of submarine in the sea trial. Improved type of TAS winch was verified in accordance with design requirement. Also, validity of suggested methods were verified by the sea trial.

Dynamic Fracture Analysis of High-speed Impact on Granite with Peridynamic Plasticity (페리다이나믹 소성 모델을 통한 화강암의 고속 충돌 파괴 해석)

  • Ha, Youn Doh
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.32 no.1
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    • pp.37-44
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    • 2019
  • A bond-based peridynamic model has been reported dynamic fracture characteristic of brittle materials through a simple constitutive model. In the model, each bond is assumed to be a simple spring operating independently. As a result, this simple bond interaction modeling restricts the material behavior having a fixed Poisson's ratio of 1/4 and not being capable of expressing shear deformation. We consider a state-based peridynamics as a generalized peridynamic model. Constitutive models in the state-based peridynamics are corresponding to those in continuum theory. In state-based peridynamics, thus, the response of a material particle depends collectively on deformation of all bonds connected to other particles. So, a state-based peridynamic theory can represent the volume and shear changes of the material. In this paper, the perfect plasticity is considered to express plastic deformation of material by the state-based peridynamic constitutive model with perfect plastic flow rule. The elastic-plastic behavior of the material is verified through the stress-strain curves of the flat plate example. Furthermore, we simulate the high-speed impact on 3D granite model with a nonlocal contact modeling. It is observed that the damage patterns obtained by peridynamics are similar to experimental observations.

Arctic Sea Ice Motion Measurement Using Time-Series High-Resolution Optical Satellite Images and Feature Tracking Techniques (고해상도 시계열 광학 위성 영상과 특징점 추적 기법을 이용한 북극해 해빙 이동 탐지)

  • Hyun, Chang-Uk;Kim, Hyun-cheol
    • Korean Journal of Remote Sensing
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    • v.34 no.6_2
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    • pp.1215-1227
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    • 2018
  • Sea ice motion is an important factor for assessing change of sea ice because the motion affects to not only regional distribution of sea ice but also new ice growth and thickness of ice. This study presents an application of multi-temporal high-resolution optical satellites images obtained from Korea Multi-Purpose Satellite-2 (KOMPSAT-2) and Korea Multi-Purpose Satellite-3 (KOMPSAT-3) to measure sea ice motion using SIFT (Scale-Invariant Feature Transform), SURF (Speeded Up Robust Features) and ORB (Oriented FAST and Rotated BRIEF) feature tracking techniques. In order to use satellite images from two different sensors, spatial and radiometric resolution were adjusted during pre-processing steps, and then the feature tracking techniques were applied to the pre-processed images. The matched features extracted from the SIFT showed even distribution across whole image, however the matched features extracted from the SURF showed condensed distribution of features around boundary between ice and ocean, and this regionally biased distribution became more prominent in the matched features extracted from the ORB. The processing time of the feature tracking was decreased in order of SIFT, SURF and ORB techniques. Although number of the matched features from the ORB was decreased as 59.8% compared with the result from the SIFT, the processing time was decreased as 8.7% compared with the result from the SIFT, therefore the ORB technique is more suitable for fast measurement of sea ice motion.

Rent-seeking Analysis of the Cultural Voucher from the Viewpoint of Culture and Arts Management (문화예술경영 관점으로 본 문화이용권사업의 지대추구론적 분석)

  • Bae, Seung-Ju
    • Management & Information Systems Review
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    • v.38 no.3
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    • pp.151-170
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    • 2019
  • This study deals with the rent-seeking behavior that exist in cultural voucher from the viewpoint of culture and arts management. Art organizations open to consumers, producers and governments of the arts are dependent on the internal and external influence of an open system. Researcher has found rent-seeking in the course of introducing policies and legalization of the cultural voucher business which has been promoted in the direction of democratization of culture or cultural democracy. Cultural voucher business is a legal term. Although the government has increased the budget or tried to change the policies of the cultural voucher business, the implementation of the cultural voucher business has been opposed to the diversity of consumption and equity as the consumption of genre and the concentration of the capital region have increased. These results were structurally related to the process of legalization and rent-seeking behavior in bureaucracy. This study reaffirms that the efficient operation standard of the cultural voucher business is a balance between the choice of the beneficiary, the competition of the supplier, and access to the cultural voucher. And the theory of rent-seeking was applied as a criterion to analyze this balance. Thus, it is suggested that the criteria of evaluation and improvement to check the conservativeness of bureaucrats are needed to establish a legal system applied to the purpose of 'cultural democracy' and 'democratization of culture' ideology and to guarantee individual creativity and autonomy.

Solitary Work Detection of Heavy Equipment Using Computer Vision (컴퓨터비전을 활용한 건설현장 중장비의 단독작업 자동 인식 모델 개발)

  • Jeong, Insoo;Kim, Jinwoo;Chi, Seokho;Roh, Myungil;Biggs, Herbert
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.41 no.4
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    • pp.441-447
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    • 2021
  • Construction sites are complex and dangerous because heavy equipment and workers perform various operations simultaneously within limited working areas. Solitary works of heavy equipment in complex job sites can cause fatal accidents, and thus they should interact with spotters and obtain information about surrounding environments during operations. Recently, many computer vision technologies have been developed to automatically monitor construction equipment and detect their interactions with other resources. However, previous methods did not take into account the interactions between equipment and spotters, which is crucial for identifying solitary works of heavy equipment. To address the drawback, this research develops a computer vision-based solitary work detection model that considers interactive operations between heavy equipment and spotters. To validate the proposed model, the research team performed experiments using image data collected from actual construction sites. The results showed that the model was able to detect workers and equipment with 83.4 % accuracy, classify workers and spotters with 84.2 % accuracy, and analyze the equipment-to-spotter interactions with 95.1 % accuracy. The findings of this study can be used to automate manual operation monitoring of heavy equipment and reduce the time and costs required for on-site safety management.