• Title/Summary/Keyword: East Sea coast

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The Analysis of Radio Interference between Korea and China/japan using Split-step DMFT Algorithm (Sp1it-step DMFT 알고리즘을 이용한 한국과 중국/일본간 전자파 간섭특성 분석)

  • 정남호;손호경;김봉석;백정기;이형수
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.13 no.2
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    • pp.196-208
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    • 2002
  • Since radio interference has occurred in the TRS frequency band in the south coastal area, Korea from 1994, similar interference has been observed in the mobile-cellular frequency band. Measurement showed that the sources of the radio interference are those from the base stations for digital cellular systems in Japan. This because the receiving frequency of the base stations in Korea is same as the transmitting frequency of the base stations in Japan. Since the distance between Korea and Japan is 240 ~ 300 km, we can conclude that the main reason of the interference is ducting. In this paper a ducting channel is modeled by split-step DMFT algorithm, and simulation results for measured index profile far east coast and west sea area are analyzed.

Trihalomethane formation potential of drinking water sources in a rural location

  • Rajamohan, R.;Ebenezer, Vinitha;Rajesh, Puspalata;Venugopalan, V.P.;Natesan, Usha;Murugesan, V.;Narasimhan, S.V.
    • Advances in environmental research
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    • v.1 no.3
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    • pp.181-189
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    • 2012
  • Trihalomethanes, produced as a result of chlorination of drinking water, are considered a potential health hazard. The trihalomethane formation potential (THMFP) of a raw water source may indicate the maximum trihalomethanes (THMs) that are likely to be produced when chlorine reacts with natural organic matter (NOM) present in the water. A study was conducted to evaluate the THMFP in seven different drinking water sources in the vicinity of Kalpakkam, a rural township, on the east coast of India. Water from seven stations were analysed for THMFP. THMFP was compared with surrogate parameters such as dissolved organic carbon (DOC), ultraviolet absorbance ($UV_{254}$) and bromide. The data showed that THMFP was high in water from open wells as compared to closed bore wells, possibly due to more photosynthetic activity. Proximity to sea, and consequently the levels of bromide, was an important factor that influenced THM formation. THM surrogate parameters showed good correlation with THMFP.

RCS of Ballistic Missile Based on Radar Position (레이더 위치에 따른 탄도미사일의 RCS 특성)

  • Park, Tae-Yong;Lim, Jae-Sung
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.40 no.1
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    • pp.209-216
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    • 2015
  • It is difficult to detect, track and intercept ballistic missile because of its high speed and short flight time from launching to target area. In order to increase the success rate of a ballistic missile interceptor, it is important to track the flight trajectory for a long time after the detection in the early launch. Radar Cross Section(RCS) of the target is important when the target to be detected by the radar, and the difference between the RCS value greatly changes depending on the viewing direction during the flight missile trajectory. In this paper, it is assumed that a ballistic missile is launched at east coast of North Korea, observe that missile by a land based radar and sea deployed radar. And it is analyzed and compared that RCS difference of ballistic missile.

Backshore Erosion due to High Swell Waves (너울성고파랑에 기인한 후빈 배후 침식)

  • Kim, Kyu Han;Shim, Kyu Tae
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.24 no.5
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    • pp.366-371
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    • 2012
  • High swell has been known for the one of the main causes of beach erosion in the east coast of Korea. In this study, coastal topography changes due to high swells are simulated to find its effect on the backshore by using movable bed experiments and numerical experiments. Sea bottom topographical changes due to various incident waves were investigated using CSHORE model in the numerical experiments. Furthermore, the mechanism and the phenomena of beach erosion due to waves and high swells on the foreshore and backshore were analyzed and compared with movable bed hydraulic experiments.

First Record of Lumpenopsis pavlenkoi Soldatov, 1916 (Pisces: Stichaeidae) Collected from Gosung, Gangwon Province, Korea (한국 강원도 고성에서 채집된 장갱이과 어류 1미기록종 Lumpenopsis pavlenkoi Soldatov, 1916)

  • Lee, Hye-Lyang;Lee, Soo Jeong;Kim, Jin-Koo
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.53 no.6
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    • pp.960-964
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    • 2020
  • For the first time, a single specimen (68.47 mm in total length) of Lumpenopsis pavlenkoi Soldatov, 1916 belonging to the family Stichaeidae was collected from the northernmost area of the eastern coast of Korea (Gosung, Gangwon Province) in April, 2020, using square net (1.0 m width, 0.3 m height, 2.0 mm mesh size). This species is characterized by elongated and compressed body, absence of lateral line and cirri on head, presence of scales on cheek, dorsal fin with only 50 spines, anal fin with 2 spines and 30 soft rays, and separated operculum and isthmus. The body is yellowish with 7 saddles. The new Korean name "Kko-ma-be-do-ra-chi-sog" is proposed for the genus Lumpenopsis, and "Deung-jeom-kko-ma-be-do-ra-chi" is proposed for the species L. pavlenkoi.

Effects of Serotonin Injection on Spawning and Modulation of Sperm Densities for Preventing Polyspermy to Achieve Larval Development in Eastern Gooeyduck Clam Panopea sp. Distributed on the East Coast of Korea (동해안 서식 동해코끼리조개(Panopea sp.)의 세로토닌 주사에 따른 산란 유발과 다정수정 방지를 위한 정자밀도에 따른 유생발달)

  • Jin-Chul Park;O-Nam Kwon
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.56 no.5
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    • pp.644-650
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    • 2023
  • We examined the effects of serotonin on the spawning response, sperm motility, and D-shaped larva production in Eastern Gooeyduck clam Panopea sp. based on the sperm densities at fertilization and washing after mixing the eggs and sperm. The highest spawning induction was found showed in females and males injected with 1 mL of 2 mM serotonin. The spawning responses in females and males were higher at concentrations greater than 1 mM and 0.75 mM, respectively. Regarding the activities of sperm in sea water after serotonin injection, the sperm showed activity at >90.0% until 120 mins. We also examined the effects of sperm concentration at the fertilization and washing times after mixing the eggs and sperm. We confirmed that washing within 1 minute at a concentration of 1,500 sperms/mL or less can prevent egg destruction by polyspermy and secure a large number of D-phase larvae. These results should be useful for developing the aquaculture process for Eastern Gooeyduck clam, Panopea sp.

Microbiological Quality of the Shellfish-growing Waters and Mussels in Changseon, Namhae, Korea (남해 창선해역의 해수 및 진주담치의 위생학적 안전성 평가)

  • Yoo, Hyun-Duk;Ha, Kwang-Soo;Shim, Kil-Bo;Kang, Jin Yeong;Lee, Tae-Seek;Kim, Ji-Hoe
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.43 no.4
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    • pp.298-306
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    • 2010
  • A sanitary survey was conducted to evaluate the water quality and mussel (Mytilus edulis) conditions of two administrative shellfish growing waters: those designated as shellfish growing water for export, and adjacent waters on the east coast of Changseon Island, Namhae, Korea. In all, 1,656 seawater and 166 mussel samples were collected at 46 stations for seawater and five stations for the shellfish from January 2007 to December 2009. Both seawater and mussels were examined for total coliforms and fecal coliforms. The standard plate count and most probable number of Escherichia coli were also determined for the shellfish samples. The range of the geometric means and the estimated 90th percentiles of fecal coliform for seawater samples at each station were <1.8-4.1 MPN/100 mL and <1.8-22.3 MPN/100 mL, respectively. The sanitary conditions for both shellfish growing areas, the designated shellfish growing area and adjacent area in Changseon, met the 'Approved area' criteria of the United States National Shellfish Sanitation Program. The range of E. coli detected in mussels in these areas was <20-500 MPN/100 g; and only 3 of 166 samples exceeded 230 MPN/100 g, the European standard for the consumption of raw bivalves. Therefore, the mussel farms in the Changseon area are classified as 'Class A' according to criteria set in European Community regulations. However, the levels of E. coli in mussels in parts of the designated shellfish growing area and adjacent area exceeded the bacterial limits after rainfall exceeding 45 mm. Further studies are needed to fully define the conditions leading to a temporary closure to harvest after a rainfall event.

Study of a Recurring Anticyclonic Eddy off Wonsan Coast in Northern Korea Using Satellite Tracking Drifter, Satellite Ocean Color and Sea Surface Temperature Imagery (위성원격탐사를 이용한 동해 원산연안의 재발생 와동류 연구)

  • 서영상;장이현;김정희
    • Korean Journal of Remote Sensing
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    • v.16 no.3
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    • pp.211-220
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    • 2000
  • Even though recurring eddies at the terminal end of the East Korean Warm Current have been identified in the thermal infrared imagery from the NOAA/AVHRR sensor and ocean color data from Orbview-2/SeaWiFS sensor, it is difficult to make observation in the field regarding recurring eddies located around the Wonsan coastal area in North Korea. But we could get in situ data related to an eddy from an ARGOS satellite tracking drifter trapped in the eddy on January 4th, 1999. An ARGOS drifter, a NOAA satellite tracked buoy was trapped by the eddy during January 4th.March 18, 1999. The ARGOS drifter rotated 10 times per 72 days on the edge of the eddy located at $39^{\circ}N$, $129^{\circ}E$. The diameter of the eddy was about 100 km. The horizontal rotation velocity of the recurring cold-core anti-cyclonic eddy was 1.53 km/h(42 cm/sec). The sea surface temperatures of the eddy varied from $14.7^{\circ}C$ on January 5, 1999 to $9.6^{\circ}C$ on March 18,1999. To study the mechanism of the recurring eddy. we tried to find out the relationship between the vector of the drifter moving in the eddy and the wind vector in Sokcho and Ulleung Island located near the eddy in southern Korea, and the difference in sea level between Ulleung Island and Mukho. We hope the results of this study would be useful for calibration and validation data of simulation and numerical modeling studies of the recurring eddy.

Statistical Method and Deep Learning Model for Sea Surface Temperature Prediction (수온 데이터 예측 연구를 위한 통계적 방법과 딥러닝 모델 적용 연구)

  • Moon-Won Cho;Heung-Bae Choi;Myeong-Soo Han;Eun-Song Jung;Tae-Soon Kang
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.29 no.6
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    • pp.543-551
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    • 2023
  • As climate change continues to prompt an increasing demand for advancements in disaster and safety management technologies to address abnormal high water temperatures, typhoons, floods, and droughts, sea surface temperature has emerged as a pivotal factor for swiftly assessing the impacts of summer harmful algal blooms in the seas surrounding Korean Peninsula and the formation and dissipation of cold water along the East Coast of Korea. Therefore, this study sought to gauge predictive performance by leveraging statistical methods and deep learning algorithms to harness sea surface temperature data effectively for marine anomaly research. The sea surface temperature data employed in the predictions spans from 2018 to 2022 and originates from the Heuksando Tidal Observatory. Both traditional statistical ARIMA methods and advanced deep learning models, including long short-term memory (LSTM) and gated recurrent unit (GRU), were employed. Furthermore, prediction performance was evaluated using the attention LSTM technique. The technique integrated an attention mechanism into the sequence-to-sequence (s2s), further augmenting the performance of LSTM. The results showed that the attention LSTM model outperformed the other models, signifying its superior predictive performance. Additionally, fine-tuning hyperparameters can improve sea surface temperature performance.

Plankton Community Response to Physico-Chemical Forcing in the Ulleung Basin, East Sea during Summer 2008 (2008년 하계 울릉분지에서 관측된 물리·화학적 외압에 대한 플랑크톤 군집의 반응)

  • Rho, Tae-Keun;Kim, Yun-Bae;Park, Jeong-In;Lee, Yong-Woo;Im, Dong-Hoon;Kang, Dong-Jin;Lee, Tong-Sup;Yoon, Seung-Tae;Kim, Tae-Hoon;Kwak, Jung-Hyun;Park, Hyun-Je;Jeong, Man-Ki;Chang, Kyung-Il;Kang, Chang-Keun;Suh, Hae-Lip;Park, Myung-Won
    • Ocean and Polar Research
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    • v.32 no.3
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    • pp.269-289
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    • 2010
  • In Summer 2008, a multidisciplinary survey was conducted onboard R/V Haeyang 2000 to understand plankton response to the three distinct physico-chemical settings that developed in the Ulleung Basin of the East Sea. Baseline settings of hydrographic conditions included the presence of the thin (<20 m) Tsushima Surface Water (TSW) on top of the Tsushima Middle Water (TMW). It extends from the Korea Strait to $37^{\circ}N$ along the $130^{\circ}E$ and then turns offshore and encompasses the relatively saline (T>$26^{\circ}C$, S>33.7) Ulleung Warm Eddy surface water centered at $36.5^{\circ}N$ and $131^{\circ}E$. A relatively colder and saline water mass appeared off the southeastern coast of Korea. It was accompanied by higher nutrient and chlorophyll-a concentrations, suggesting a coastal upwelling. Most of the offshore surface waters support low phytoplankton biomass (0.3 mg chl-a $m^{-3}$). A much denser phytoplankton biomass (1-2.3 mg $m^{-3}$) accumulated at the subsurface layer between 20-50 m depth. The subsurface chlorophyll-a maximum (SCM) layer was closely related to the nutricline, suggesting an active growth of phytoplankton at depth. The SCM developed at shallow depth (20-30 m) near the coast and deepened offshore (50-60 m). A fucoxanthin/zeaxanthin ratio was high in coastal waters while it was low in offshore waters, which indicated that diatoms dominate coastal waters while cyanobacteria dominate offshore waters. The community structure and biomass of phytoplanktonare closely related to nitrogen availability. Zooplankton biomass was higher in the coastal region than in the offshore region while species richness showed an opposite trend. Zooplankton community structure retained a coastal/offshore contrast. These suggest that summer hydrography is a stable structure, lasting long enough to allow a hydrography-specific plankton community to evolve.