• Title/Summary/Keyword: Marine Engineering System

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Coastal Protection with the Submerged Artificial Bio-reefs (인공 Bio-reef에 의한 해변침식방지)

  • Lee Hun;Lee Joong-Woo;Lee Hak-Sung;Kim Kang-Min
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2004.11a
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    • pp.159-166
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    • 2004
  • The beach, a margin between the sea and the land, is an extremely dynamic zone, for it is here that the motion of the sea interacts with the sediment, rock of the land or the artificial barriers. In order to prohibit or retard erosions due to the extreme Typhoon or storm induced waves, man has constructed these of temporary or more permanent nature, but they caused problems of other erosions from the secondary effect of them and a bad influence on the seascape. In considering the energy available to accelerate sediment transport and erosion in the surf zone, where the waves are broken, and offshore beyond the breaker line, the wave height and the wave period should be taken account. Hence, we tried to present an applicability of the submerged artificial Bio-reefs analyzing waves by a numerical model such that they could reduce the wave power without the secondary effect and restoration of marine ecologies. A new technique of beach preservation is by artificial reefs with artificial and/or natural kelps or sea plants. By engineering the geometry of the nearshore reef, the wave attenuation ability of the feature can be optimized Higher, wider and longer reefs provide the greatest barrier against wave energy but material volumes, navigation hazards, placement methods and other factors require engineering considerations for the overall design of the nearshore reefs.

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Characteristics of Unconfined Compressive Strength of Dredged Clay Mixed with Friendly Soil Hardening Agent (준설토와 친토양 경화재 혼합지반의 일축강도특성)

  • Oh, Sewook;Yeon, Yonghum;Kwon, Youngcheul
    • Journal of the Korean GEO-environmental Society
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    • v.17 no.10
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    • pp.73-81
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    • 2016
  • In the construction on low strength and high compressible soft ground, the many problems have been occurred in recent construction project. therefore, the soil improvement have been developed to obtain high strength in relatively short period of curing time. Based on the laboratory tests using undisturbed marine clay, the effect of improvement on soft ground was estimated. Deep mixing method by cement have been virtually used for decades to improve the mechanical properties of soft ground. However, previous researches set the focus on the short term strength the about 10% of cement treated clay. In this paper, cement and Natural Soil Stabilizer (NSS) were used as the stabilizing agent to obtain trafficability and mechanical strength of the soft clay. Based on the several laboratory tests, optimum condition was proposed to ensure the mechanical strength and compressibility as the foundation soil using cement and NSS mixed soil. Finally, research data was proposed about the applicability of NSS as the stabilizing agent to soft clay to increase the mechanical strength of soil.

Remote Seabed Classification Based on the Characteristics of the Acoustic Response of Echo Sounder: Preliminary Result of the Suyoung Bay, Busan (측심기의 음향반사 특성을 이용한 해저퇴적물의 원격분류: 부산 수영만의 예비결과)

  • Kim Gil Young;Kim Dae Choul;Kim Yang Eun;Lee Kwang Hoon;Park Soo Chul;Park Jong Won;Seo Young Kyo
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.35 no.3
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    • pp.273-281
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    • 2002
  • Determination of sediment type is generally based on ground truthing. This method, however, provides information only for the limited sites. Recent developments of remote classification of seafloor sediments made it possible to obtain continuous profiles of sediment types. QTC View system, which is an acoustic instrument providing digital real-time seabed classification, was used to classify seafloor sediment types in the Suyoung Bay, Pusan. QTC View was connected to 50 kHz echo sounder, All parameters of QTC View and echo sounder are uniformly kept during survey. By ground truthing, the sediments are classified into seven types, such as slightly gravelly sand, slightly gravelly sandy mud, gravelly muddy sand, clayey sand, sandy mud, slightly gravelly muddy sand, and rocky bottom. By the first remote classification using QTC View, four sediment types are clearly identified, such as slightly gravelly sand, gravelly mud, slightly gravelly muddy sand, and rocky bottom. These are similar to the result of the second survey. Also the result of remote classification matches well with that of ground truthing, but for sediment type determined by minor component. Therefore, QTC View can effectively be used for remote classification of seafloor sediments.

A Study on the Enhancement of DEM Resolution by Radar Interferometry (레이더 간섭기법을 이용한 수치고도모델 해상도 향상에 관한 연구)

  • Kim Chang-Oh;Kim Sang-Wan;Lee Dong-Cheon;Lee Yong-Wook;Kim Jeong Woo
    • Korean Journal of Remote Sensing
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    • v.21 no.4
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    • pp.287-302
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    • 2005
  • Digital Elevation Models (DEMs) were generated by ERS-l/2 and JERS-1 SAR interferometry in Daejon area, Korea. The quality of the DEM's was evaluated by the Ground Control Points (GCPs) in city area where GCPs were determined by GPS surveys, while in the mountain area with no GCPs, a 1:25,000 digital map was used. In order to minimize errors due to the inaccurate satellite orbit information and the phase unwrapping procedure, a Differential InSAR (DInSAR) was implemented in addition to the traditional InSAR analysis for DEM generation. In addition, DEMs from GTOPO30, SRTM-3, and 1:25,000 digital map were used for assessment the resolution of the DEM generated from DInSAR. 5-6 meters of elevation errors were found in the flat area regardless of the usage and the resolution of DEM, as a result of InSAR analyzing with a pair of ERS tandem and 6 pairs of JERS-1 interferograms. In the mountain area, however, DInSAR with DEMs from SRTM-3 and the digital map was found to be very effective to reduce errors due to phase unwrapping procedure. Also errors due to low signal-to-noise ratio of radar images and atmospheric effect were attenuated in the DEMs generated from the stacking of 6 pairs of JERS-1. SAR interferometry with multiple pairs of SAR interferogram with low resolution DEM can be effectively used to enhance the resolution of DEM in terms of data processing time and cost.

Application of Seawater Plant Technology for supporting the Achievement of SDGs in Tarawa, Kiribati (키리바시 타라와의 지속가능발전목표 달성 지원을 위한 해수플랜트 기술 활용)

  • Choi, Mi-Yeon;Ji, Ho;Lee, Ho-Saeng;Moon, Deok-Soo;Kim, Hyeon-Ju
    • Journal of Appropriate Technology
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    • v.7 no.2
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    • pp.136-143
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    • 2021
  • Pacific island countries, including Kiribati, are suffering from a shortage of essential resources as well as a reduction in their living space due to sea level rise and coastal erosion from climate change, groundwater pollution and vegetation changes. Global activities to solve these problems are being progressed by the UN's efforts to implement SDGs. Pacific island countries can adapt to climate change by using abundant marine resources. In other words, seawater plants can assist in achieving SDGs #2, #6 and #7 based on SDGs #14 in these Pacific island countries. Under the auspice of Korea International Cooperation Agency (KOICA), Korea Research Institute of Ships and Ocean Engineering (KRISO) established the Sustainable Seawater Utilization Academy (SSUA) in 2016, and its 30 graduates formed the SSUA Kiribati Association in 2017. The Ministry of Oceans and Fisheries (MOF) of the Republic of Korea awarded ODA fund to the Association. By taking advantage of seawater resource and related plants, it was able to provide drinking water and vegetables to the local community from 2018 to 2020. Among the various fields of education and practice provided by SSUA, the Association hope to realize hydroponic cultivation and seawater desalination as a self-support project through a pilot project. To this end, more than 140 households are benefiting from 3-stage hydroponics, and a seawater desalination system in connection with solar power generation was installed for operation. The Association grows and supplies vegetable seedlings from the provided seedling cultivation equipment, and is preparing to convert to self-support business from next year. The satisfaction survey shows that Tarawa residents have a high degree of satisfaction with the technical support and its benefits. In the future, it is hoped that SSUA and regional associations will be distributed to neighboring island countries to support their SDGs implementations.

Design and Realization of the Sailing System for Mille and Small Leisure Ships (중소형 레저선박용 운항시스템 설계 및 구현)

  • Oh, Hong-Geun;Park, Jung-Min;Kim, Chul-Won
    • The Journal of the Korea institute of electronic communication sciences
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    • v.12 no.3
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    • pp.411-418
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    • 2017
  • In the domestic case, although technological capabilities are recognized globally in the IT field, it is actually that the technical capabilities of the domestic leisure ship market which is formed mainly by fishing vessels are not beyond their technical capabilities At the point where the GNP of our country already goes over 22,000 dollars, the demand for the products related to the middle and small leisure boats is gradually increasing, but most of the high added value products depend on the imports from U.S.A. and Europe. And in case of the cars, with the Car Navigation as the start, products which satisfies various demands of the users are coming out in large quantity and now the IT technology is the necessity which can not be lived without in the car industry. Thus, if the digital ship navigator which jointed the recent ICT technology which was applied to the land for the domestic middle and small leisure ships by utilizing the embedded hardware technology and mapping technology which are credible is developed and distributed, it will become not only the opportunity to improve the industry related to middle and small ship IT, but also, the export about overseas market can be expected.

A Study on the Service Quality Analysis and the Difference Between User Groups in Bulk Terminals of Busan Port (벌크터미널 서비스품질 분석 및 이용주체별 차이에 관한 연구: 부산항 벌크터미널을 중심으로)

  • Lee, Kyung-Nam;Yang, Han-Na;Wang, Gao-Feng;Shin, Chang-Hoon
    • Journal of Navigation and Port Research
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    • v.40 no.4
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    • pp.223-230
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    • 2016
  • While marine transport freight is steadily increasing, people are more interested in terminals handling cargo. But the domestic researches on terminals were almost on container terminal. This study attempted to study the service quality for bulk terminals. The users of bulk terminal services were divided into shipowners and shippers to compare their differences by using bulk terminal service provided. During the attributions proposed in this study, Tangibles were descripted by the numbers of berth or depth, facilities, and so on. So it was suitable to consider the tangibles by formative indicators. And also this study has tried using "reflective model" and "formative model" to make a measurement model for comprehensive analyses. The results showed that all of the items were significant except the relation between empathy and performance satisfaction in the overall measurement model analyses. User groups difference analyses results have showed that the trust responsiveness impact on performance satisfaction was more importantly assessed by shippers than by shipowners. It was expected to use the results of this study as a good strategic resource to help bulk terminal administrators make various expansion plans to improve the bulk terminal's competitiveness in the future.

Molecular Monitoring of Eukaryotic Plankton Diversity at Mulgeum and Eulsukdo in the Lower Reaches of the Nakdong River (낙동강 하류 물금과 을숙도 수환경의 진핵 플랑크톤 종조성에 대한 분자모니터링)

  • Lee, Jee Eun;Lee, Sang-Rae;Youn, Seok-Hyun;Chung, Sang Ok;Lee, Jin Ae;Chung, Ik Kyo
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.17 no.3
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    • pp.160-180
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    • 2012
  • We have studied the eukaryotic plankton species diversity to compare the community structure of fresh and brackish waters in the lower reaches of the Nakdong River using metagenomic methods. We constructed 18S rDNA clone libraries of total DNAs extracted from environmental water samples collected at Mulgeum (MG100929, fresh) and Eulsukdo bridge (ES, brackish). Through the steps of colony PCR, PCR-RFLP, sequencing and similarity analysis, we discovered the diverse species composition of eukaryotic plankton. Total 338 clones (170 at MG100929 and 168 at ES) were analyzed, and then we found 74 phylotypes (49 for MG100929 and 25 for ES). From the phylogenetic analysis, we confirmed various eukaryotic plankton of broad range of taxonomic groups, including Stramenopiles, Cryptophyta, Viridiplantae, Alveolata, Rhizaria, Metazoa, and Fungi. We also found several unreported species in Korea and candidates of new taxonomic entities at levels higher than genus. Especially, the cryptic species diversity including unreported phylotypes of Pirsonia (Stramenopiles) and Perkinsea (Alveolata) suggests that the molecular monitoring method can produce new informative biological data in monitoring the changes in the Nakdong River Mouth ecosystem.

Regional Realtime Ocean Tide and Storm-surge Simulation for the South China Sea (남중국해 지역 실시간 해양 조석 및 폭풍해일 시뮬레이션)

  • Kim, Kyeong Ok;Choi, Byung Ho;Lee, Han Soo;Yuk, Jin-Hee
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.30 no.2
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    • pp.69-83
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    • 2018
  • The South China Sea (SCS) is a typical marginal sea characterized with the deep basin, shelf break, shallow shelf, many straits, and complex bathymetry. This study investigated the tidal characteristics and propagation, and reproduced typhoon-induced storm surge in this region using the regional real-time tide-surge model, which was based on the unstructured grid, resolving in detail the region of interest and forced by tide at the open boundary and by wind and air pressure at the surface. Typhoon Haiyan, which occurred in 2013 and caused great damage in the Philippines, was chosen as a case study to simulate typhoon's impact. Amplitudes and phases of four major constituents were reproduced reasonably in general, and the tidal distributions of four constituents were similar to the previous studies. The modelled tide seemed to be within the acceptable levels, considering it was difficult to reproduce the tide in this region based on the previous studies. The free oscillation experiment results described well the feature of tide that the diurnal tide is prevailing in the SCS. The tidal residual current and total energy dissipation were discussed to understand the tidal and sedimentary environments. The storm-surge caused by typhoon Haiyan was reasonably simulated using this modeling system. This study established the regional real-time barotropic tide/water level prediction system for the South China Sea including the seas around the Philippines through the validation of the model and the understanding of tidal characteristics.

GIS-Based Suitable Site Selection for Aquaculture Using Scope for Growth of Styela Clava (GIS 기반의 미더덕 SFG(Scope for Growth)를 이용한 양식장의 적지선정)

  • Park, Jung-Hyun;Suh, Yong-Cheol
    • Journal of the Korean Association of Geographic Information Studies
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    • v.16 no.3
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    • pp.81-90
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    • 2013
  • The purpose of this paper is to do GIS-based suitable site selection using Scope for Growth index of Styela clava in Jindong Bay. The aquaculture of Styela calva is only conducted in Korea, especially Jindong Bay. Suspended culture of Styela clava was initiated in 2001 and the annual production reached 15,084M/T, but declined to 1,412M/T in 2005. The annual production was increased slightly to 2,484M/T in 2012 but the production is lower than the beginning yield. Scope for Growth(SFG) can indicate interrelationships between environment and organism growth index in aquaculture. GIS-based suitable site selection can be available by the concept of SFG, and fishery management system can be constructed for the sustainable production. As a result of the assessment of habitat suitability, Jindong Bay's SFG value ranges 0.054~0.57J/day and Styela clava farm's SFG values range 0.054~0.57J/day, either. The correlation between Styela clava farm's SFG and the actual production has a good result, as r=0.786, p<0.05. The construction of fishery management system using habitat suitability index ensures the reasonable site selection and the sustainable production in aquaculture farm. It introduces an objective method for the interrelationships between the environmental variation and the organism growth. Consequently, it can promote the decision making practices for the sustainable fishery management.