• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.3
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• pp.563-572
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• 2020

Tidal flats provide important indicators that inform the condition of the environment, so we need to monitor them systematically. Currently, the projects to monitor tidal flats by periodically observing the creatures in tidal flats are underway. Still, it is done in a way that people observe directly, so it is not systematic and efficient. In this paper, we propose a background modeling method for tidal flat images that can be applied to a system that automatically monitors creatures living in tidal flats using sensor network technology. The application of sensor network technology makes it difficult to collect enough images due to the limitation of transmission capacity. Therefore, in this paper, we propose a method to effectively model the background and generate foreground maps by reflecting the characteristics of tidal flat images in the situation where the number of images to be used for analysis is small. Experimental results show that the proposed method models the background of a tidal flat image easily and accurately.

• Journal of Ocean Engineering and Technology
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• v.21 no.2 s.75
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• pp.42-49
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• 2007

It has been known that shallow-water regions, such as tidal flats, sea grass and sea weed beds have water purification capability, and they also serve as nursery grounds for many fishes. On the other hand, tidal flat areas are economically attractive sites for reclamation, to be used for developing industries. When developing shallow-water areas, we have to propose a plan to mitigate the environmental impact associated with such a development plan. However, it is difficult to estimate the affects on the ecosystem and water purification, and the literature related to this matter is insufficient. In order to evaluate the ability of coastal tidal flat and to predict the future changes, it is necessary to develop a reliable prediction technique and construction of data by using a field investigation. In this study, we carried out a numerical model test for the tidal flat ecosystem, using the pelagic system and the benthic system, simultaneously, in order to show a change in the tidal flat ecosystem. The flow of nitrogen, phosphorus and carbon has been identified as a primary consideration of marine ecosystem components, and the capability of water purification and the change of the tidal flat were predicted using this flow. In order to make a more reliable prediction, a field investigation to determine tide, current and creatures of the object coastal area has been done. The purification capability of this shallow-water region is estimated from the model results. According to the results of experiments, the tidal flat has a capability of water purification (Sink) of 11mgN/m2/day, but the other area has a load (Source) of 20mgN/m2/day. As a result, we could confirm that the tidal flat of an object coastal area plays an important role in water purification.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.5
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• pp.947-956
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• 2021

As an interest in metaverse increases, there are many studies to apply virtual reality to indirect experiences. Virtual reality is increasingly being used not only for entertainment such as games but also for educational content. A key technology of indirect experience is modeling an object to provide a realistic experience to the user. Natural environments such as tidal flats change with time, and many living things also live there. In this paper, we propose a method for creating experiential content that accurately models the ecological environment of tidal flats. The proposed method explains how to naturally model the temporal change of tidal flats. We also explain how to model a crab, a creature that inhabits the tidal flat, in the forms of an NPC using the behavior tree. Implementation results show that the proposed method uses simple algorithms but expresses the shapes of tidal flats well.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.639-643
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• 2007

Tidal regime change with general hydrolic condition change is examined, according to Garolim Tidal Power Plant (TPP) operation. Numerical model has been developed for the Yellow and East China Seas region, in order to consider the tidal regime change by the TPP operation. The changes of tidal elevation and tidal current inside the Garolim bay are also investigated in details, along with examining the change of the tidal flat area with operation. The field measurement for the tide and current have been carried out for the validation of the numerical model and for understanding the state of current system in the present state.

• New & Renewable Energy
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• v.3 no.2 s.10
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• pp.3-10
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• 2007

Tidal regime change with general hydrolic condition change is examined, according to Garolim Tidal Power Plant (TPP) operation. Numerical model has been developed for the Yellow and East China Seas region, in order to consider the tidal regime change by the TPP operation. The changes of tidal elevation and tidal current inside the Garolim bay are also investigated in details, along with examining the change of the tidal flat area with operation. The field measurement for the tide and current have been carried out for the validation of the numerical model and for understanding the state of current system in the present state.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.734-738
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• 2002

We present spectral characteristics of tidal flat sediments and algal mat that were tested in the Gomso and Saemangum tidal flats, Korea. The objective of this study is to investigate the spectral reflectance and the radar scattering modeling in the tidal flats. Ground truth data obtained in the tidal flats include grain size, soil moisture content and its variation with time, surface roughness, chlorophyll, ground leveling, and field spectral reflectance measurement. The concept of an effective exposed area (EEA) is introduced to accommodate the effect of remnant surface water, and it seriously affects the reflection of short wavelength infrared and microwave. The nin size of 0.0625 mm has been normally used as a critical size of mud and sand discrimination. But we propose here that 0.25 mm is more practical grain size criterion to discriminate by remote sensing. Algal mat is the primary product in tidal flats, and it is found to be very important to understand spectral characteristics for tidal flat remote sensing. We have also conducted radar scattering modeling, and showed L-band HV-polarization would be the most effective combination.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.22 no.5
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• pp.333-343
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• 2010

In Mokpo coastal zone, the characteristics showing ebb-dominant tidal flow was confirmed by analysis of observed tide and tidal currents, Physical factors occurring ebb-dominant flow were reviewed. Influence of critical depth for drying, bottom shear stress, coastal reclamation, tidal amplitude, nonlinear tide, and eddy viscosity on the change of ebb-dominant flow was investigated by applying a two-dimensional circulation model. The simulation results for a variety of conditions showed that eddy viscosity and critical depth for drying does little or no impact on the generation of asymmetric flow. Strong bottom friction stress makes ebb-dominant flow clearly. Change of tidal flat into land swells ebb- dominant flow, and change of tidal flat into sea disappears ebb-dominant flow. Nonlinear tides play a decisive role in the generation of asymmetrical tidal flow. Non-linear tides should be included in the open boundary conditions of hydrodynamic modeling in the Mokpo coastal zone.

• Atmosphere
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• v.27 no.4
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• pp.399-409
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• 2017

The impact of land cover changed by tidal flats on local meteorology in Gyeonggi Bay was quantitatively evaluated based on a numerical modeling approach during 18 days (21 June to 9 July 2013). The analysis was carried out using three sets of simulation scenarios and the land cover of tidal flats for each simulation was applied as follows: (1) the herbaceous wetland representing coastal wetlands (i.e., EXP-BASE case), (2) the barren or sparsely vegetated representing low tide (i.e., EXP-LOW case), (3) the water bodies representing high tide (i.e., EXP-HIGH case). The area of tidal flats was calculated as about $552km^2$ (the ratio of 4.7% for analysis domain). During the daytime, the change (e.g. wetlands to water) of land cover flooded by high tide indicated the decrease of temperature (average $3.3^{\circ}C$) and the increase of humidity (average 13%) and wind speed (maximum $2.9m\;s^{-1}$). The changes (e.g. wetlands to barren or sparsely vegetated) of land cover induced by low tide were smaller than those by high tide. On the other hands, the effects of changed land cover at night were not apparent both high tide and low tide. Also, during the high tide, the meteorological change in tidal flats affected the metropolitan area (about 40 km from the tidal flat).

• Journal of The Korean Astronomical Society
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• v.23 no.2
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• pp.97-105
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• 1990

The tidal radii of globular clusters reflect the tidal field of the Galaxy. The mass distribution of the Galaxy thus may be obtained if the tidal fields of clusters are well known. Although large amounts of uncertainties in the determination of tidal radii have been obstacles in utilizing this method, analysis of tidal density could give independent check for the Galactic mass distribution. Recent theoretical modeling of dynamical evolution including steady Galactic tidal field shows that the observationally determined tidal radii could be systematically larger by about a factor of 1.5 compared to the theoretical values. From the analysis of entire sample of 148 globular clusters and 7 dwarf spheroidal systems compiled by Webbink (1985), we find that such reduction from observed values would make the tidal density (the mean density within the tidal radius) distribution consistent with the flat rotation curve of our Galaxy out to large distances if the velocity distribution of clusters and dwarf spheroidals with respect to the Galactic center is isotropic.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.8 no.1
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• pp.103-113
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• 1996

Two-dimensional finite element hydrodynamic models for long wave simulation usually adopt fixed land boundary. However moving boundary treatment is strongly required in the simulation of tidal flats for west and south coast of Korea. In this study very efficient and realistic moving boundary treatment is applied by considering incident long wave surface slope. Developed STEP-CM (Superior Two-step Explicit Program for Coastal Modeling) ,shows numerically stable results in comparative study for idealized one-dimensional channel. Real application of the model is done for Chonsu Bay where tidal flats are distributed along the coast. Nonlinear tidal current and tidal flat effects are easily simulated in STEP-CM and resulting circulations are detected around headland of Wonsan Island.