• Title/Summary/Keyword: Sea operation

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A Study on Environmental Impact Assessment System of Seoul City (서울시 환경영향평가 제도에 대한 연구)

  • Kim, Im-Soon;Han, Sang-Wook
    • Journal of Environmental Impact Assessment
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    • v.16 no.6
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    • pp.467-483
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    • 2007
  • Environmental Impact Assessment (EIA) is a kind of planning technique to seek ways to minimize environmental impact, a scheme to encourage sustainable development. With the launch of the Ministry of Environment in 1980, the EIA was introduced in Korea. Its full operation was initially driven by regulations on documenting EIA reports in 1981, which was piloted as a decision-making scheme where final decision were made at the development department after considering opinions suggested by the Ministry of Environment. At that time, dominance of the economic logic overwhelmed environ-friendly opinions, but thanks to the fourth revision of the Environmental Conservation Law in 1986, private projects came to be included on the EIA list. This was a turning point for the EIA to become a regulatory system. Local governments are also conducting the EIA regardless of the national-level EIA. In order to prevent and resolve increasingly severe environmental problems in Seoul in advance due to various construction projects, the Seoul Metropolitan Government, for the first time as a local government in Korea, legislated city decrees to introduce the EIA which has been underway from September 1, 2002. In particular, the Seoul government, unlike the Ministry of Environment, has included construction works on the list of evaluation projects, adopting the scoping and screen procedure scheme. In addition, complementing operational setbacks, the city government has revised and implemented decrees and enforcement laws on the Impact Assessment on Environment, Transportation and Disasters by shortening the consultation period, eliminating the submission of reports on construction, and expanding the waiver requirements in consultation over the reports. Therefore, development measures for the EIA scheme of the Seoul Metropolitan Government will be the target of the research. To that end, the up-to-date data of the Ministry of Environment, the Seoul government and local governments was collected, and latest materials from the EU, previous research and the Internet were gathered for analyses. By doing so, the flow of the EIA was reviewed, and the EIA schemes of local governments under the national EIA were analyzed. Furthermore, based on the Seoul government's recent data on the EIA based on the decrees, the background and legislation of the Seoul government's EIA were analyzed along with the developments for the environmental organizations. Setbacks were derived from the implementation period, evaluation procedures, consultation period and details of the EIA, and corresponding development measures were proposed.

Integrated Ray Tracing Model for In-Orbit Optical Performance Simulation for GOCI (통합적 광추적 모델에 의한 해양탑재체 GOCI의 궤도 상 광학 성능 검증)

  • Ham, Seon-Jeong;Lee, Jae-Min;Kim, Seong-Hui;Yun, Hyeong-Sik;Gang, Geum-Sil;Myeong, Hwan-Chun;Kim, Seok-Hwan
    • Journal of Satellite, Information and Communications
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    • v.1 no.2
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    • pp.1-7
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    • 2006
  • GOCi (Geostationary Ocean Color Imager) is one of the COMS payloads that KARI is currently developing and scheduled to be in operation from around 2008. Its primary objective is to monitor the Korean coastal water environmental condition. We report the current progress in development of the integrated optical model as one of the key analysis tools for the GOCI in-orbit performance verification. The model includes the Sun as the emitting light source. The curved Earth surface section of 2500 km x 2500 km includingthe Korean peninsular os defined as a Lambertian scattering surface consisted of land and sea surface. From its geostationary orbit, the GOCI optical system observes the reflected light from the surfaces with varying reflectance representing the changes in its environmental conditions. The optical ray tracing technique was used to demonstrate the GOCI in-orbit performances such as red tide detection. The computational concept, simulation results and its implications to the on-going development of GOCI are presented.

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A Study on the Research Trends in Unmanned Surface Vehicle using Topic Modeling (토픽모델링을 이용한 무인수상정 기술 동향 분석)

  • Kim, Kwimi;Ma, Jungmok
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.7
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    • pp.597-606
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    • 2020
  • Because the USV(Unmanned Surface Vehicle) is capable of remote control or autonomous navigation at sea, it can secure the superiority of combat power while minimizing human losses in a future combat environment. To plan the technology for the development of USV, the trend analysis of related technology and the selection of promising technology should be preceded, but there has been little research in this area. The purpose of this paper was to measure and evaluate the technology trends quantitatively. For this purpose, this study analyzed the technology trends and selected promising/declining technologies using topic modeling of papers and patent data. As a result of topic modeling, promising technologies include control and navigation, verification/validation, autonomous level, mission module, and application technology, and declining technologies include underwater communication and image processing technology. This study also identified new technology areas that were not included in the existing technology classification, e.g., technology related to research and development of USV, artificial intelligence, launch/recovery, and operation, such as cooperation with manned and unmanned systems. The technology trends and new technology areas identified through this study may be used to derive key technologies related to the development of the USV and establish appropriate R&D policies.

A Study on East Asian Regional Electronic Navigational Chart Coordinating Center Establishment Strategy (동아시아 전자해도 지역 공급센터 구축방안 연구)

  • Kim, Ho-Yoon;Oh, Se-Woong;Shim, Woo-Sung;Suh, Sang-Hyun
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.18 no.3
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    • pp.213-220
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    • 2012
  • International Maritime Organization made International Convention for the Safety of Life at Sea to require all ships to carry official charts, both paper and electronic, and is especially encouraging the use of Electronic chart display and information system (ECDIS). Recently, the argument that all Electronic Charts(ENC) displayed in ECDIS should be distributed through Regional ENC Coordinating Center is being raised within the IHO. The use of ECDIS was generalized, but the existing two RENCs in Europe are thought to be not enough. Especially, East Asian region, due to its rapid growth in economy and marine traffic, RENC is found necessary. This research establishes the legitimacy and strategy of East Asian RENC by defining the roles of RENC based on the IMO ECDIS Mandatory Carriage Requirement and RENC operation status through suggesting a "Phase-In" RENC model, which was built upon the strategy of East Asian Hydrographic Commission(EAHC).

Distribution of Dissolved Heavy Metals in Surface Seawaters Around a Shipyard in Gohyun Bay, Korea (고현만의 조선소 주변 표층해수 중의 용존 중금속 농도 분포)

  • Kim, Kyung Tae;Ra, Kongtae;Kim, Joung Keun;Kim, Eun Soo;Kim, Chong Kwan;Shim, Won Joon
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.18 no.1
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    • pp.36-44
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    • 2015
  • The spatial and temporal distribution of dissolved trace metals has been studied to identify trends in space and time and to evaluate the pollution status in a semi-closed bay (Gohyun bay), Korea. Surface seawater samples were collected over four seasons at 18 stations in the bay between 2003 and 2004 and once at 7 stations around a large shipyard in May 2004. The concentration of Cd, Co, Cu, Ni, Pb, and Zn in seawater in February and May were highly variable in space, showing the higher value relative to other season. Those metals concentrations were decreased from inner-to outer-stations. In around the shipyard, Cu, Pb and Zn showed the higher variability depending on time. Cu and Zn concentrations at the sites around the shipyard had 2 times higher values compared with the average of inner stations in Gohyun bay. The very high correlations between salinity and either Cu and Zn has been showed. Especially, there was a significant relationship between Cu and Zn. We recognize that the shipyard is major source of Cu and Zn in seawater. Therefore, marine environment management policy such as the prevention and control of heavy metal input from a shipyard is required.

Separation Characteristics of $CH_4/CO_2$ Mixed Gas by Polyamide Composite Membrane (Polyamide 복합막을 이용한 메탄/이산화탄소 혼합기체의 분리 특성)

  • Lee, Jae-Hwa;Lee, Geon-Ho;Choi, Kyung-Seok;Poudel, Jeeban;Kim, Soo-Ryong;Oh, Sea-Cheon
    • Journal of the Korean Applied Science and Technology
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    • v.29 no.3
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    • pp.478-485
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    • 2012
  • Polymers are widely used as membrane material for performing the separation of various gaseous mixtures due to their attractive permselective properties and high processability. The separation characteristics of $CH_4$ and $CO_2$ mixed gas using polyamide composite membrane has been studied in this work. The sample gas was prepared by mixing pure methane and carbon dioxide. Permeation tests were carried out at different operation conditions. Feed flow rates were varied between 800~1000 $cm^3/min$, and the stage cuts were varied between 50~60%. The gas inlet pressure and the temperature were varied as 6 bar and $30{\sim}70^{\circ}C$, respectively. The effects of the above mentioned parameters were investigated to estimate the permeability of $CH_4$ and $CO_2$, and the selectivity of $CO_2$ was also calculated for all conditions. The Arrhenius plots were also performed to obtaine the activation energies of $CH_4$ and $CO_2$ permeabilities.

Cavitation Analysis on Ship Seawater Pump Using CFD (CFD를 이용한 선박용 해수펌프의 공동현상에 대한 분석)

  • Kim, Bu-Gi;Kim, Hong-Ryeol;Yang, Chang-Jo;Kim, Jun-Ho
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.23 no.4
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    • pp.400-406
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    • 2017
  • The model used in this study was reversed to analyze the cause of excessive damage that occurred inside the rotating system and pipe system of a centrifugal-type seawater pump on a ship. For this purpose, internal flow analysis on a cooling seawater pump was performed using CFD. As a result, the shape and boundary conditions of the target pump were set by reverse engineering, and pump efficiency at a design operating point of $125m^3/h$ was calculated as 85.3 % with a head of 32.0 m. The maximum efficiency point of the target pump was estimated to be 86.2 % at $150m^3/h$, but this differed from the actual operating point. At $112.5m^3/h$, which was the lowest flow point, flow was unstable due to the characteristics of the low flow point and analysis convergence was not good. The purpose of this study was to clarify the cause of ongoing cavitation in seawater pumps and piping systems in operation. Future research will be needed to clarify causes for pipe systems in the future by performing calculations for the total piping system of an inlet and outlet, in addition to measuring the flow rate of each branch pipe.

Fault Location Estimation Algorithm in the Railway High Voltage Distribution Lines Using Flow Technique (반복계산법을 이용한 철도고압배전계통의 고장점표정 알고리즘)

  • Park, Kye-In;Chang, Sang-Hoon;Choi, Chang-Kyu
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.22 no.2
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    • pp.71-79
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    • 2008
  • High voltage distribution lines in the electric railway system placed according track with communication lines and signal equipments. Case of the over head lines is occurrence the many fault because lightning, rainstorm, damage from the sea wind and so on. According this fault caused protection device to wrong operation. One line ground fault that occurs most frequently in railway high voltage distribution lines and sort of faults is line short, three line ground breaking of a wire, and so on. For this reason we need precise maintenance for prevent of the faults. The most important is early detection and fast restoration in time of fault for a safety transit. In order to develop an advanced fault location device for 22.9[kV] distribution power network in electric railway system this paper deals with new fault locating algorithm using flow technique which enable to determine the location of the fault accurately. To demonstrate its superiorities, the case studies with the algorithm and the fault analysis using PSCAD/EMTDC (Power System Computer Aided Design/Electro Magnetic Transients DC Analysis Program) were carried out with the models of direct-grounded 22.9[kV] distribution network which is supposed to be the grounding method for electric railway system in Korea.

Optimal Site Selection of Floating Offshore Wind Farm using Genetic Algorithm (유전 알고리즘을 활용한 부유식 해상풍력단지 최적위치 선정)

  • Lee, Jeong-Seok;Son, Woo-Ju;Lee, Bo-Kyeong;Cho, Ik-Soon
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.25 no.6
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    • pp.658-665
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    • 2019
  • Among the renewable energy resources, wind power is growing rapidly in terms of technological development and market share. Recently, onshore wind farm have been affected by limitations of terrestrial space and environmental problems. Consequently, installation sites have been moved to the sea, and the development of floating offshore wind farms that are installed at deep waters with more abundant wind conditions is actively underway. In the context of maritime traffic, the optimal site of offshore wind farms is required to minimize the interference between ships and wind turbines and to reduce the probability of accidents. In this study, genetic algorithm based AIS(Automatic Indentification System) data composed of genes and chromosomes has been used. The optimal site of floating offshore wind farm was selected by using 80 genes and by evaluating the fitness of genetic algorithm. Further, the final site was selected by aggregating the seasonal optimal site. During analysis, 11 optimal site were found, and it was verified that the final site selected usng the genetic algorithm was viable from the perspective of maritime traffic.

Gyroscope Signal Denoising of Ship's Autopilot using Kalman Filter and Multi-Layer Perceptron (칼만필터와 다층퍼셉트론을 이용한 선박 오토파일럿의 자이로스코프 신호 잡음제거)

  • Kim, Min-Kyu;Kim, Jong-Hwa;Yang, Hyun
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.25 no.6
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    • pp.809-818
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    • 2019
  • Since January 1, 2020, the International Maritime Organization (IMO) has put in place strong regulations to reduce air pollution caused by ships by lowing the upper limit of ship fuel oil sulfur content from 3.5% to 0.5% for ships passing through all sea areas around the world. Although it is important to reduce air pollutants by using fuel oil with low sulfur content, reducing the amount of energy waste through the economic operation of a ship can also help reduce air pollutants. Ships can follow designated routes accurately even under the influence of noise using autopilot systems. However, regardless of their quality, the performance of these systems is af ected by noise; heading angles with added measurement noise from the gyroscope are input into the autopilot system and degrade its performance. A technique to solve these problems reduces noise effects through the application of a Kalman filter, which is widely used in condition estimation. This method, however, cannot completely eliminate the effects of noise. Therefore, to further improve noise removal performances, in this study we propose a better denoising method than the Kalman filter technique by applying a multi-layer perceptron (MLP) in forward direction motion and a Kalman Filter in rotation motion. Simulations show that the proposed method improves forward direction motion by preventing the malfunction of a rudder more so than merely using a Kalman Filter.