• Ocean and Polar Research
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• v.26 no.4
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• pp.685-688
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• 2004

The morphology of the post-larva of Liopropoma japonicum of the family serranidae is described from one specimen collected off Jeju Island ($32^{\circ}42'N,\;127^{\circ}45'E$) on May 3, 2001. The body is laterally compressed and caudal peduncle deep at 19.4 mm BL. Anus locates at a vertical through posteriormost(8th) dorsal-fin spine. Dorsal fin rays were VIII, 14; anal fin rays III, 10; pectroal fin rays 16; pelvic fin rays I, 5. A caudal fin is rounded. Length of elongate second and third dorsal-fin spines are 499% and 423% of the body length, respectively. A series of 50 sensory pores on body is elongated to caudal fin. Head spination is well developed. Melanophores are moderately large and dense in the head, and are small and rare in teh neck. Being freshly collected, the body color is yellowish-red and tail is semitransparent. The head is yellowish-red and the brain is dark-red.

• Journal of Korean Society for Atmospheric Environment
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• v.29 no.2
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• pp.199-210
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• 2013

Detailed 3 dimensional structure of Asian dust plume has been analyzed from the retrieved aerosol data from two different satellites which are the Korea's $1^{st}$ geostationary satellite, namely the Communication, Ocean, Meteorological Satellite (COMS) spacecraft launched in 2010, and the NASA's Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO). COMS spacecraft provides the first time resolved aerial aerosol maps by the systematically well-calibrated multispectral measurements from the Geostationary Ocean Color Imager (GOCI) instrument. GOCI data are used here to evaluate intensity, spatial distribution, and long-range transport of Asian dust plume during 1~2 May 2011. We found that the strong Asian dust plume showing AOT of 2~5 was lofted to the altitude around 2~4 km above the Earth's surface and transported over Yellow Sea with a speed of about 25 km/hr. The CALIPSO extinction coefficient and particulate depolarization ratio (PDR) profiles confirmed that nonspherical dust particles were enriched in the dust plume. This study is a first example of quantitative integration of GOCI and CALIOP measurements for clarifying the overall structure of an Asian dust event.

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.336-339
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• 2004

Communication, Ocean and Meteorological Satellite (COMS) has been developed by Korean Aerospace Research Institute (KARI) since 2003. Ocean Color Imager (OCI) is the one of COMS payloads, which will monitor the marine environment around Korean peninsula routinely with the intermediate resolution. But considering COMS is to be located in the geostationary orbit, required geographical coverage is not positioned in the nadir direction of COMS but in specific location with horizontal and vertical offsets from the nadir. In this study, coverage by OCI Field Of View (FOV) is analyzed. First of all, OCI is modeled as the sensor which is a $2,500{\times}2,500$ sized 2-D CCD and the pixel resolution is about 500m. And then, OCI is simulated to be controlled to target the required coverage accurately. As a result of it, coverage by OCI FOV is determined. Finally, all coverages by OCI FOV are mapped.

• Proceedings of the KSRS Conference
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• v.1
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• pp.475-478
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• 2006

Total primary production resulting from the photosynthetic process can be defined as the amount of organic matter produced in a given period of time. It is proportional to the chlorophyll-a (chl-a) values in the surface layer of the ocean. The MODIS board on Aqua satellite measures visible and infrared radiation in 36 wavebands, providing simultaneous images of chl-a concentration and sea surface temperature (SST) in the upper layer of the sea. The seasonal distribution of chl-a concentration during one year from April 2005 to March 2006 was examined. Light has a role of starting the seasonal cycle. The Kuroshio Current in this area induces many oceanographical features affecting to the change of seasonal control. The chl-a concentration is also seasonal, which is low in summer and high in winter. In summer, the meandering of Kuroshio Current induces strong eddies and increases the chl-a concentration. In autumn, the delayed small autumn bloom occurred until last December due to the Kuroshio Current. When the Kuroshio axis moves far from the coast, the coastal water dominates and increases the concentration even in the winter. The spring bloom starts early at the beginning of March and decreases during the spring.

• Proceedings of the KSRS Conference
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• 2007.03a
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• pp.192-197
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• 2007

한국해양연구원에서는 2008년 으 로 예정된 통신해앙기상위성(통해기)의 발사에 맞춰 통해기에 탑재된 해색센서(GOCI)자료의 수신，처리，배포를 위한 해앙위성센터 구축을 진행하고 있다. 전파수신환경，자연환경 등을 고려하여, 해양위성센터 위치를 안산(한국해양연구원 본원)으로 정하였다. 이에 따라，지금까지 안테나를 포함한 수신시스템에 대한 상세설계，내부 구조 변경，H/W 및 N/W 설계，자료처리 시스템 일부의 도입을 실시하였다. 여기에서는，해양위성센터 구축 현황을 소개하고，해색센서(GOCI)자료의 수신，처리，배포 시스템 설계 결과를 소개하고자 한다. 가장 중요한 자료 배포 시스템은 기본적으로 온라인으로 구성되며, 수신된 데이터를 1시간 내에 제공하기 위해 웹호스팅 등 외부데이터 제공 시스템도 구축하는 것을 구상 중에 있다.

• Proceedings of the KSRS Conference
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• 2007.03a
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• pp.204-209
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• 2007

수중에서의 하향 방향의 감쇠 계수 (Diffuse attenuation coefficient of down-welling irradiance, $K_d$)에 대한 연구는 상충 해양에 대한 열전달 수중에서의 광합성 및 다른 생물학적 과정에 대한 연구，해양 일차 생산력 추정, 대양 및 연안에서의 탁도 추정 등에 대한 연구의 보조 자료로서 해양원격탐사를 포함한 해양에 대한 연구에 매우 중요한 요소이다. 우리나라는 세계 최초의 정지궤도 해색 센서인 Geostationary Ocean Color Imager (GOCI)를 2008년 말에 통신해양기상위성 (COMS, Communication Ocean and Meteorological Satellite)에 탑재하여 쏘아 올릴 계획에 있다. 이 센서는 매일 한 시간 간격으로 한반도 주변 해역을 8회 이상 관측할 계획에 었다. 따라서 기존의 해색 센서들에 비해서 시간 해상도가 향상되기 때문에 해양 환경 모니터링에 있어서 많은 도움이 될 것으로 예상된다. 본 연구에서는 앞으로 운영될 GOCI 센서에 대한 수중에서의 하향 방향의 감쇠계수 (The diffuse attenuation coefficient of down-welling irradiance, $K_d$) 알고리즘을 현장 관측 값을 이용하여 미리 만들어 보고 이를 현재의 대표적인 해색 센서인 SeaWiFS 영상의$K_d$(490) product와 비교하여 보았다.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.55 no.4
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• pp.363-371
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• 2019

Thousands of demersal fishes inhabit in the waters around Korea and most of them are overexploited. One of reasons is technological development, which increases the efficiency of the vessels continuously. The analysis was conducted to identify the change of fishing power index to develop the vessel and gear technology that may have improved the fishing efficiency of the Danish seine fishery from 1960s to 2010s. Gross tonnage was decreased stably, but the horse power was increased annually. The length of ground rope, warp and hand rope was somewhat longer, but changed a little. Color fish finder was utilized from the mid-1960s and positioning system was used five years later. A hydraulic line hauler were introduced in the mid-1980s, and supply rate was gradually increased. Surveys on the supply and upgrading of fishing equipment utilized visiting researchers. Therefore, the relative fishing power index in the Danish seine fishery increased stably from 1.0 in 1970 to 1.0 in 1980, to 1.2 in 1990, to 1.3 in 2000 and to 1.3 in 2010. The results are expected to contribute to reasonable fisheries stock management.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.32 no.3
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• pp.273-285
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• 1996

Generally, the flow around the ship's hull often appear 3-dimensional separation at the bow and stem, and the vortex by this flow affects greatly the resistance propulsive efficiency and maneuverability of the ship. This study is compared the calculated result based on the streamlines calculation method with the experimental result by oil fIlm method to analyze the patterns and characteristics of the flows around the ship's hull of chine form. DTMB Series 62, 4667-1 vessel was selected as a sample ship of chine form and model ship was painted with the mixture of oil-color, paint, and poly wax at the surface of the vessel and tested in the model towing tank of Inha University. The results obtained in this study are listed briefly as follows ; 1. For the single chine form, after $4\frac{1}{2}$ station the streamlines are crossed at the chine line and the streamlines are converted to the vortex follow the chine line. 2. For the single chine form, the vortex appered increases and severely in and arround the stern. 3. The approximate streamlines for the ship's hull of chine form can be assigned by the use of the Watanabe's basic transformation formular.

• Laser Solutions
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• v.18 no.2
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• pp.1-4
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• 2015

This study is related to the surface hardening treatment to spheroidal graphite cast iron for die by using high power diode laser. Laser device used in this experiment is capable of real-time laser power control. This is because the infrared temperature sensor (two color pyrometer) attached to the optical system measures the surface temperature of specimen and adjusts the laser power in real time. The surface treatment was carried out with the change of heat treatment temperature at the beam travel speed 3 mm/sec. Hardened width and depth was measured and hardened zone was analyzed by micro vickers hardness test in order to research the optimum condition of heat treatment. The changes in microstructure of the hardened zone also was examined. As a result of hardness measurement and observations on microstructure of hardened zone, hardness increased over three times as compared with base metal because the martensite was formed on the matrix structure.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.57 no.3
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• pp.205-213
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• 2021

Two specimens of Hemitrygon izuensis (395.8-471.5 mm in disc width), belonging to the family Dasyatidae (Myliobatiformes), were collected from the waters off north-eastern Jeju-do Island in June 2016 and Pohang in August 2019. This species was characterized by having no spots on dorsal side of disc, white ventral tail fold and short preorbital snout length (15.6-18.3% of disc width). This species is similar to H. akajei and H. sinensis reported in Korea, but differs in small denticles on mid-line of dorsal surface of disc (absent in H. izuensis vs. present in H. akajei and H. sinensis), the length of ventral tail fold (28.1-31.0% in H. izuensis vs. 48.0-48.6% in H. akajei vs. 45.0% in H. sinensis), color of ventral tail fold (white in H. izuensis vs. black in H. akajei and H. sinensis) and small tubercles on the posterior part of tail (absent in H. izuensis vs. present in H. akajei and H. sinensis). We suggest a Korean name for H. izuensis as "I-ju-gal-saeg-ga-o-li" following Kim et al. (2019).