• 한국해양학회지
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• v.5 no.1
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• pp.37-40
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• 1970

This work concerns age studies of the spanish mackerel by vertebrae. The spanish mackerel samples were obtained mainly from Yosoo and Inchon regions during July to December, 1969. A total of 292 fish was collected during the present study. Except the vertebrae, the incremental growth is found to be vague or complicated on the most bony parts in spanish mackerel. The spanish mackerel has 50 vertebrae, and the size of vertebra varies according to its position. After several studies, therefore, sample centrum was selected from the 23rd vertebra throughout the present study. Sample centrum was then stained with Alizarin Red S. and examined under binocular stereoscopic microscope illuminated by reflected light. The surface of the centrum shows many ring-marks running parallel to the edge. The ring-marks were counted and the measurements of centrum radius (R) and radii of the ring-marks (r$\_$i/) were made by eyepiece micrometer. From available data, the average of each ring-mark radius was found to be; r$\_$1/=2.05mm, r$\_$2/=3.11mm, r$\_$3/=4.05mm, r$\_$4/=4.89mm, r$\_$5/=5.70mm and r$\_$6/=6.47mm, respectively. The mean fork length at the time of ring-mark formation was calculated to be; l$\_$1/=297.6mm, l$\_$2/= 390.1mm, l$\_$3/=472.2mm, l$\_$4/=545.5mm, l$\_$5/=616.2mm, and l$\_$6/= 683.4mm, respectively.

• Korean Journal of Ecology and Environment
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• v.50 no.1
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• pp.46-56
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• 2017

The Youngsan River estuary was physically changed by the construction of a sea embankment at near the mouth of estuary. Weirs were also constructed recently in the freshwater zone and it was reported that algal blooms occur more frequently. The freshwater introduced into saltwater zone from sluice gates of the embankment affects water quality but it has not been addressed that how the freshwater inputs influence the health of marine ecosystem. In this study, we used the data of water properties and phytoplankton communities collected at three stations for 4 days including before the freshwater discharge, during the discharge and after 1 and 2 days of discharge events. WQI(water quality index), TRIX (trophic status index) and P-IBI(phytoplankton index of biotic integrity) were used to evaluate the ecosystem health and long-term data were also utilized to determine the criteria for P-IBI. The results showed that grades of the ecosystem health assessed by the indices were low at the station near the gates and increased as downstream. However, the temporal pattern of grades was different depending on methods. Grades of WQI and TRIX decreased during the discharge and restored after the discharge whereas the grades of P-IBI decreased slightly even after the discharge. This suggests that P-IBI is more applicable to estuarine systems where experience extreme change of water properties than WQI and TRIX since P-IBI includes phytoplankton that can respond quickly to the change.

• 한국지구과학회:학술대회논문집
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• 2010.04a
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• pp.70-70
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• 2010

이 연구의 목적은 귀추적 탐구 방법과 관련된 전략들을 적용하여 지구온난화에 관련되어 측정된 다양한 유형의 데이터를 관련된 사실, 원리, 법칙, 선행 연구 결과 등을 토대로 지구통합적인 관점과 지구계를 구성하는 요소들 간의 상호작용과 영향을 중심으로 재해석하고 이해하는 것이다. 지구과학(지구시스템과학)의 학문 성격, 최근 동향, 본성 및 탐구 대상의 특성에 대한 내용과 지구과학의 본질적 속성에 잘 부합하는 귀추적 탐구 방법에 대해 학습한 후, 학생들은 인천 및 다양한 지역의 기상과 해양 자료 분석을 통하여 관찰되는 현상(결과)의 원인과 영향을 파악하는 연구 활동을 하였다. 이 과정에서 귀추적 탐구를 충분히 이해할 수 있도록, 과학 탐구에서 귀추적 탐구 방법을 사용하는 과학자들의 예시와 모의 활동을 통하여, 귀추적 탐구 방법에 사용되는 다양한 사고 전략(예, 데이터의 재구성 전략, 유추 전략, 개념적 결합 전략 등)에 대한 예시를 경험하였다. 학생들은 지구온난화에 관련되어 나타나는 현상(조사된 사항 포함)과 영향에 대해 지구시스템적으로 이해하고 재해석하기 위해 지구시스템을 구성하는 요소(예, 수권, 대기권)와 관련된 데이터 정보를 검색하고 수집하였다. 1) 지구시스템과 지구온난화에 대한 조사하고, 2) 지구온난화 및 기후변화의 변동성 확인한 후, 3) 지구온난화와 관련된 선행 연구 결과 분석하였다. 또한, 지구과학의 본질적 속성에 잘 부합하는 귀추적 탐구 방법의 이해와 적용하는 과정에서 1) 지구 온난화 및 기후 변화의 실태 파악하고, 2) 인천 지역의 월별, 계절별 기온 변화 분석 및 경향 조사(탐색: 연구문제 규명)한 후, 3) 인천과 속초 지역의 기온, 수온의 변화 추이 및 분석 (조사: 원인 조사 과정)하였다. 4) 속초 지역의 평균해면기압변화 추이 및 분석한 후, 그 결과를 토대로 5) 문헌조사 및 선행연구 결과 분석을 통한 지구 온난화의 영향을 미치는 요인 재검토 및 확인(선택 및 설명)하여, 6) 인천지역과 속초지역의 지구온난화 원인 분석 및 문제점 보완(설명)하기 위해 7) 겨울철 지구온난화가 더 심각한지 부산지역과 포항지역의 자료 분석을 통하여 연구 결과 내용의 보완 (추가 조사 및 설명)한 후, 8) 분석 결과 및 해석 내용을 전문가와 상담 실시하였다. 이 연구는 연구를 진행하면서 얻은 결과를 교육적 측면에서 다시 정리해 보면 다음과 같다. 우선, 학생들의 지구환경적 문제 해결 과정에서 귀추적 탐구 방법을 활용한 문제 해결 능력을 향상시켰다. 아울러, 지구과학의 탐구 본성, 최근 동향, 탐구대상의 특성 등의 학습을 통해 지구과학도로서의 기본적인 소양과 자질 향상에 기여하였으며, 사회과학의 연구방법을 순수과학연구에 접목하여 과학자로서의 문제해결 능력과 시스템 사고력을 향상시켰다.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.3
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• pp.318-325
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• 2015

Korea has very strong shipbuilding industry in the world, so many new ships are constructed in Korean shipyards. These built vessels are carrying out sea trial at sea before delivering to shipowner, and sea trial ships cause navigation risk to other passing vessels to accomplish sea trial tests as quick turning, zigzag maneuvering and crash astern etc. in traffic congestion conditions. It occurred more than 1 collision accident related sea trial for recent 5 years. It has been increased about 30% of risk because of navigation of sea trial vessel by marine traffic flow simulation. This paper analyzed marine traffic density surveyed by AIS data for 7 days, and investigated position of marine accidents for 5 years in Korean coastal waterway, it established the sea trial prohibition areas as 10/100 level of total marine traffic volume, which is considered no danger for ship operator. This analyzed maritime safety law for setting of the prohibition waters to propose the basic legal system. It makes contribution to marine pollution prevention by setting of the sea trial prohibition water to improve the ship's navigation safety.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.2
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• pp.177-186
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• 2017

This paper attempts to quantitatively assess the public value that has been assigned to this government plan by employing a contingent valuation technique. Data gathering performed that professional research firm administrated a face-to-face national survey of 1,000 randomly-selected households. A one-and-one-half-bound model was adopted to elicit willingness to pay (WTP) responses, and the payment vehicle used was income tax. The WTP model used in this study is based on a utility difference approach and the spike model. The results showed that the public value of conserving green turtles was estimated to be 2,570 Korean Won per household over the next 10 years as of 2016, statistically significant at the 1% level. Expanding the values considered to include the national population gives a public value of 48.7 billion Korean Won. Thus, the public value of rescuing, rehabilitating, and releasing green turtles that have been caught by fishermen, collided with fishing boats, and died in nets through the government program is not small.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.2
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• pp.187-193
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• 2017

This study evaluated tidal stream energy resources according to tidal flow properties around Uido off the west coast of, Jeollanam-do, South Korea. A feasibility study was first carried out through the collection of bathymetry data and tidal phase information. For this simulation, a depth-averaged 2D ADCIRC (Advanced Circulation) model for real sea situations was applied to a Finite Element Method (FEM) approach for tides given the variation of tidal current speed. Hydrodynamics were simulated with 4 major tidal constituents (M2, S2, K1, and O1) after setting up 4 observation points. From the real depth-averaged model simulation results, it was found that the spring tide Higher High Water (HHW) and tidal current speed values at the 4 observation points were about 2.2 m and 1.33 m/s, respectively. The ADCIRC model results were analyzed with reference to the Korea Hydrographic and Oceanographic Agency's (KHOA) observed data for verification. Furthermore, using topographical characteristics via the Tidal Flux Method (TFM), tidal energy density distribution was calculated, indicating a maximum tidal energy density of about $1.75kW/m^2$ for the 5 assessment areas around Uido. The tidal energy density was evaluated with consideration given to topographical characteristics as well as tidal elevation and tidal current speed to determine an optimum tidal farm candidate.

• Korean Journal of Remote Sensing
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• v.37 no.3
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• pp.627-636
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• 2021

Although many studies on ship detection using synthetic aperture radar (SAR) satellite images are being conducted around the world, there are still very few employing SAR microsatellites, as most of the microsatellites are optical satellites. Recently, the ICEYE and Capella Space have embarked on the development of microsatellites with SAR sensor, and similar projects are being initiated globally in line with the flow of the new space era [e.g., for the ICEYE: 18 satellites (~2021); Capella Space: 36 satellites (~2023); and the Coast Guard SAR: 32 satellites in the early development stage]. In preparation for these new systems, it is important to review the SAR microsatellite system and the recent advances in this technology. Accordingly, in this paper, the current status and characteristics of optical and SAR microsatellite constellation operation are described, and studies using them are investigated. In addition, based on the status and characteristics of the representative SAR microsatellites, specifically the ICEYE and Capella systems, methods for using SAR microsatellite data for ship detection applications are described. Our results confirm that the SAR microsatellites operate as a constellation and have the advantages of short revisit cycles and quick provision of high-resolution images. With this technology, we expect SAR microsatellites to contribute greatly to the monitoring a wide-area target vessel, in which the spatiotemporal resolution of the imagery is especially important.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.7
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• pp.820-829
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• 2020

Because ships have limited support from land, it is necessary to equip them with automatic external defibrillators (AEDs) in preparation for the incidences of cardiac arrest patients and to properly place and manage AEDs. The seafarer must have the ability to use the AEDs. This is a study to identify the placement and management of AEDs in order to increase the utilization of AEDs in ships, analyze the ability of seafarers to use AEDs and their intention to use it, and suggest improvement plans. The study was conducted from September 9, 2019, to February 20, 2020, and a total of 244 ships and 244 seafarers were surveyed. The data were analyzed by the frequency, percentage, and chi-square test using SPSS WIN 23.0 program. As a result, most of the ships with one AED number were identified, and some ships with insufficient AED placement and management were also identified. A total of 142 seafarers (58.2 %) had experience in participating in AED education; 136 seafarers (55.7 %) had intention to use AEDs; and the most barrier factor was "I don't know how to use" (63.0 %). The intention to use AEDs was high among seafarers in the position of the captain, navigator, and deck department personnel, and when they had an experience in AED training and the training period was less than six months, they were active in using AEDs. In addition, efforts to raise an awareness and education of AEDs are required for occupational groups other than navigators who are not willing to use AEDs in ships, and it is necessary to review appropriate retraining cycles through an evaluation of the seafarer's ability to use AEDs.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.151-151
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• 2023

본 연구는 호우(heavy rain) 발생 시 대기 중 미세먼지(particulate matter, PM) 저감효과를 규명하고 강우 지속에 따른 빗물 수질(pH, 전기전도도(electrical conductivity, EC), 수용성 이온) 분석을 통해 대기 중 PM이 빗물 수질에 미치는 영향을 평가하였다. 2020년 3월부터 2021년 2월까지강우 강도(7.5 mm/h)를 기준으로 총 6회의 강우를 대상으로 하였으며 빗물 샘플은 집수장치를 통해 50 mL를 연속적으로 수집하여 수질을 분석하였다. 대기 중 PM_2.5 (≤ 2.5 ㎛ in diameter) 및 PM₁₀ (≤ 10 ㎛ in diameter) 농도는 기상청 내 부산 남구 대연동 관측소의 automatic weather system (AWS)에서 측정된 일평균 자료를 이용하였다. 강우에 따른 대기 중 PM의 저감효율은 상대적으로 PM₁₀에서 뚜렷하게 나타났으며, 특히 강우 강도 7.5 mm/h 이상(유형 1)의 호우 발생 시60% 이상의 저감효율을 보였다. 반면, 강우 강도 7.5 mm/h 이하(유형 2)일 때는 10% 이하의 저감효율을 보였으며, 강우 지속에 따라 대기 중 PM₁₀ 농도가 증가하는 경향을 보이기도 하였다. 총108개의 빗물 샘플 수질을 분석한 결과, 유형 1의 경우 초기 빗물의 평균 EC는 58.5 µS/cm으로 상대적으로 높았으며 대기 중 PM₁₀과 양의 상관관계(r = 0.99)를 보였고 평균 pH는 4.3으로 산성도가 높게 나타났으며 대기 중 PM₁₀과 음의 상관관계(r = -0.99)를 보였다. 반면, 유형 2의 경우 대기 중 PM₁₀과 EC (r = -0.56) 및 pH (r = -0.41) 간 뚜렷한 상관관계가 나타나지 않았다. 또한 강우가 지속됨에 따라 EC와 수용성 양이온(Na⁺, Mg²⁺, K⁺, Ca²⁺, NH₄⁺) 및 음이온(Cl^-, NO₃^-, SO₄^2-)의 농도는 지속적으로 감소하는 경향을 보였으나 pH의 경우 강우 강도에 따라 증감의 경향이 다르게 나타났다. 유형 1의 경우 강우 지속에 따라 pH가 증가하여 산성도가 낮아졌으나 유형 2는 pH의 증감 형태를 뚜렷하게 확인하기 어려웠다. 연구 결과를 통해 강우 초기 높은 강도로 강우가 지속될 경우 대기 중 PM₁₀이 빗물 수질에 영향을 미칠 수 있는 것으로 판단되며, 이에 따라 호우 발생 시 강우가 대기 중 오염물질을 지표면으로 유입시킬 수 있는 매개체로 작용할 수 있음을 지시한다.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.7
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• pp.819-827
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• 2023

If respiratory arrest occurs or cardiopulmonary resuscitation (CPR) is performed for a long period on board ships, CPR with rescue breathing (not compression-only CPR) is required. Accordingly, ships must have resuscitation equipment for oxygen supply, and seafarers must have the maritime competence to use it. This study aimed to analyze the placement status of resuscitation equipment on ships and seafarers' intention to use them in order to increase the usability of resuscitation equipment on board ships and propose improvement measures. The study was conducted from February 2, 2023, to April 21, 2023, and a total of 340 seafarers were surveyed. The data were analyzed by frequency, percentage, and chi-square test using SPSS WIN 23.0. The results showed that the checking of resuscitation equipment was high among seafarers in the positions of officer, captain, deck department personnel, and ocean-going personnel. The intention of seafarers to use resuscitation equipment was low, and the main barrier was the lack of knowledge on how to use. Among the general characteristics of the study participants, those whose rank was that of officer or captain, whose working department was the deck, voyage who were ocean-going, and who managed a gross tonnage of 20,000 tons or more had a high intention to use resuscitation equipment. Participants who knew the necessity of rescue breathing and had received practice and equipment-based training were active in using resuscitation equipment. Therefore, a system should be developed so that all ships can be equipped with resuscitation equipment, and an environment must be created to increase accessibility to resuscitation equipment on board ships. In addition, an education system based on practical and resuscitation equipment training must be established to ensure that seafarers have maritime competence.