• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1048-1049
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• 2015

The sihwa tidal power plant is the first tidal power plant in korea and the biggest of the world. The tidal power turbine is operated by tidal energy. The tidal energy is generated by the relative motion of the earth and celestial masses specially the sun and the moon, which interact via gravitational forces. The tidal power is estimated by the predicted the tidal amplitude and phase. This paper gives a process of estimate of tidal power using Matlab T-tide based on tide prediction. The proposed method is tested using actual recorded data comparing to predicted date.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 2002.08a
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• pp.208-211
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• 2002

The Kyunggi Bay (125-l28E, 36-38N) is a macro-tidal bay in the western central port of Korean Peninsula(Fig. 1). The Bay characterizes its feature as wide tidal flats, deep tidal channels and tidal sand ridges running in parallel to tidal flows. The macro-tidal range (up to approximately 8.6m) and consequent strong tidal currents erode the bottom sediment and selectively transport to the low-energy area forming tidal ridges or tidal flats. (omitted)

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.5 no.2
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• pp.151-171
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• 1993

The review presented herein covers most of previous works on tidal models of the East China Sea and the Yellow Sea performed over past two decades including some earlier efforts. General description of tides in the region is given based on both numerically derived tidal charts, current ellipses and intelligently drawn empirical tidal charts. Some aspects of bottom tidal dissipation, tidal mixing, tidal sedimentation and tidal circulation utilizing the numerical tidal models are presented, and further discussions on inherent problems and development of the models are also given.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1997.10a
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• pp.111-124
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• 1997

With the combination of existing tidal predictio model and numerical tidal model, the efficient tidal prediction system was formulated and applied to the neighboring area of Pusan port. Because all tidal constituents for prediction (normally 69 constituents are used) can't be considered due to difficulties on computing efforts, some errors between the observed and predicted values were inevitably occurred. But it was confirmed that the practical results with about 10% of relative errors were obtained if four major tidal constituents(M$_2$, S$_2$. $K_1$, $O_1$) are used at least. Thus, if other constituents than four major tidal constituents are additornaly used, more accurate results will be obtained . Furthermore, if the databases of harmonic constants in coastal waters is made in advance using the numberical tidal model, prompt tidal prediction could be achieved whenever required.

• Ocean Systems Engineering
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• v.13 no.3
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• pp.247-268
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• 2023

Tidal stream energy extraction remains a site-specific resource due to the "first generation" criteria requiring high-velocity tidal streams. Most studies on tidal energy and turbine blade design heavily focus on installation sites with higher velocity conditions that are non-existent in tropical countries such as the Philippines. To shorten this gap, this review paper tackles tidal turbine design considerations for low-energetic regions such as the tropics. In-depth discussions of operating principles, methods of analysis, and designs of tidal turbine blades are presented. Notable tidal stream projects around the world are also mentioned in the paper. Also, it provides a perspective on the potential of this renewable energy to produce electricity for various sites in the Philippines. Finally, the paper emphasizes the need for new tidal turbine blade designs to be viable in tropical regions, such as the Philippines.

• Ocean and Polar Research
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• v.24 no.4
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• pp.331-343
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• 2002

The southern tidal flat of Kanghwa Island with an area of approximately $90km^2$ is one of the biggest flats on the west coast of Korea. Surface sediments for sedimentary analyses were sampled at 83 stations in August 1997, September 1999 and August 2000. The very poorly-sorted mud sediments were predominant in the eastern part of the tidal flat, whereas the poorly-sorted sand-mud mixed sediments were dominant in the western part. The area of muddy sediment distribution diminished, but that of sandy mud sediment extended to southeastward tidal flat for three years. In the western part of tidal flat, deposition occurred during the period of spring to summer, whereas erosion occurred in winter. Sediment accumulation rates during three years indicated that the sediments deposited continuously in the eastern part of tidal flat, whereas eroded in the western part of tidal flat. Recently, construction of artificial structures such as new airport, island-connecting bridges and dikes near the tidal flat might change tidal current and river flow pattern. In order to reduce the ecological damage and to preserve tidal-flat environment, it is necessary to Investigate long-term impacts on sedimentary environment and ecology.

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.140-143
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• 2004

The west coast of the Korean Peninsula is famous for its large tidal range (up to 9 m) and vast tidal flats. With comparison the sedimentary environments of open and close tidal flat using remote sensing, we select Kanghwa tidal flat and Hwang-Do tidal flat in Cheonsu Bay. Prior to surface sediment discrimination using remote sensing, sedimentary environments including intertidal OEM, hydraulic condition, and relationship between grain size and various tidal condition are investigated. Remote sensing has the potential to provide synoptic information of intertidal environments. The objectives of this study are: (i) to generate an intertidal digital elevation model (OEM) using the waterline method of Lansat TM/ETM+, (ii) to investigate the tidal channel distribution using texture analysis, and (iii) to analyze the relationship between surface grain size by using in-situ data and intertidal OEM and tidal channel density by using high-resolution satellite data such as IKONOS and Kompsat EOC. The results demonstrate that satellite remote sensing is an efficient and effective tool for a surface sediment discrimination and long term morphologic change estimation in tidal flats.

• Proceedings of the KSRS Conference
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• v.1
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• pp.247-249
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• 2006

The objective of this study is to detect a inter-tidal topographic change in a decade. Waterline extraction is a one of widely used method to generate digital elevation model (DEM) of tidal flat using multi-temporal optical data. This method has been well known that it is possible to construct detailed topographic relief of tidal flat using waterlines In this study, we generated two sets of tidal flat DEM for the southern Ganghwado. The DEMs showed that the Yeongjongdo northern tidal flat is relatively high elevation with steep gradients. The Ganghwado southern tidal flat is relatively low elevation and gentle gradients. To detect the morphologic change of tidal flat during a decade, we compared between early 1990's DEM and early 2000's DEM. Erosion during a decade is dominant at the west of southern Ganghwado tidal flat, while sedimentation is dominant at the wide channel between the southern Ganghwado and Yeongjongdo tidal flats. This area has been commonly affected by high current and sedimentation energy. Although we are not able to verify the accuracy of the changes in topography and absolute volume of sediments, this result shows that DEM using waterline extraction method is an effective tool for long term topographic change estimation.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.8
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• pp.856-862
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• 2015

Tidal current energy is an important alternative energy resource among the various ocean energy resources available. The tidal currents in the South-Western sea of Korea can be utilized for the development of tidal current power generation. Tidal power generation can be beneficial for many fishing nurseries and nearby islands in the southwest region of Korea. Moreover, tidal power generation is necessary for promoting energy self-sufficient islands. As tidal currents are always available, power generation is predictable; thus, tidal power is a reliable renewable energy resource. The selection of an appropriate hydrofoil is important for designing a tidal current turbine. This study concentrates on the selection and numerical analysis of four different hydrofoils (MNU26, NACA63421, DU91_W2_250, and DU93_W_210LM). Blade element momentum theory is used for configuring the design of a 50 W class turbine rotor blade. The optimized blade geometry is used for computational fluid dynamics (CFD) analysis with hexahedral numerical grids. Among the four blades, NACA63421 blade showed the maximum power coefficient of 0.45 at a tip speed ratio of 6. CFD analysis is used to investigate the power coefficient, pressure coefficient, and streamline distribution of a 50 W class horizontal axis tidal current turbine for different hydrofoils.

• The Transactions of the Korean Institute of Power Electronics
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• v.22 no.3
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• pp.199-206
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• 2017

Maximum Power Point Tracking (MPPT) control needs to generate the maximum power of a tidal current turbine. A tidal current speed sensor is required to achieve effective generated power in a tidal current generation system. The most common methods used to achieve such power is the tip speed ratio of turbine and tidal current information. However, these methods have disadvantages, such as expensive installation of the tidal current sensor, parameter errors in turbine design, and different information according to the installed position of the tidal current sensor. This paper proposes a maximum power control scheme using perturb-and-observe (P&O) for tidal current generation system. The proposed P&O MPPT scheme can achieve the maximum power without tidal current sensors and turbine design parameters. The reliability and suitability of the proposed control scheme are proven through simulation and experiment results at the tidal current generation laboratory.