• Magazine of the Korean Society of Agricultural Engineers
• /
• v.44 no.2
• /
• pp.148-160
• /
• 2002

Lake water quality assessment information is useful to anyone involved in lake management, from lakeshore owners to lake associations. 11 provides lake water quality, which can improve how to manage lake resources and how to measure current conditions. It also provides a knowledge base that can be used to protect and restore lakes. SWMM was applied to simulate the discharge and pollutant loads from Boryeong watershed, and WASP5 was applied to analyze the changes of water quality in Boryeong freshwater lake. In each model, the most suitable parameters were calculated through sensitive analysis and some parameters used default data. Simulated in SWMM and measured discharge showed the accuracy of 88.6%. T-N and T-P exceeds the criteria in the simulation of water quality in Boryeong freshwater lake, and control of pollutant loads in the main stream showed the most effective way. Integrated water quality management system was developed to give convenience in the operation of SWMM and WASP5 and data acquisition.

• 한국신재생에너지학회:학술대회논문집
• /
• 2006.06a
• /
• pp.505-508
• /
• 2006

Recently, concern for tidal power is being increased by newly recycled energy. It is important to decide on the maximum power estimate operation and it's stop by applying the difference of water level between tide level and artificial reservoir for the administration of tidal development. For maximum output of power through turbine generator, administrative variables and process on efficiency of hydraulic turbine and inflow discharge of reservoir is quite complicated because it is run through the connection of discharge-gate and turbine On the development of this model, the administrative process is decided, Operation block is presented for it's maximum power estimate.

• Korean Journal of Remote Sensing
• /
• v.25 no.6
• /
• pp.501-505
• /
• 2009

Quasi-linear bright features persistently appeared on ENVISAT ASAR images as well as X-SAR images along the tidal channels in Gyung-Gi Bay, Korea during the ebb tides. These features are induced by spatial backscatter variations caused by surface convergence (divergence) through the interaction between tidal currents and bathymetry. In order to validate this mechanism, a numerical tidal model simulation is performed on the realistic bathymetry with the tidal boundary conditions. The tide model reproduces the current convergence zone along the tidal channel during the ebb tides, which exactly coincides with the location of bright line features on SAR images.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.14 no.2
• /
• pp.121-129
• /
• 2011

The EFDC model has been simplified to enhance the computing performance in hydrodynamic modeling. Water quality module and unnecessary conditional statements were deleted in subroutine list and memory allocation. The performance of the enhanced model (EFDC-E) was checked by applying EFDC and EFDC-E models to simulating the tidal flow in Mokpo coastal zone. Both two-dimensional models and threedimensional models have been applied and compared. Three-dimensional models showed better simulation results agreeing with observed currents than two-dimensional models. The simulation results of EFDC-E model gave good results agreeing with the simulation results of EFDC model and the observed data. The computing speed of EFDC-E model is improved 3 times faster than that of EFDC model in modeling hydrodynamic flow for real time of 3 days in both 2-dimensional modeling and 3-dimensional modeling. The EFDC-E model can be used widely for hydrodynamic modeling because of improved simulation speed.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.15 no.2
• /
• pp.97-107
• /
• 2003

In order to evaluate the effect of dry-wet treatment on well developed tidal flats along the complex coastal line in the western part of Korean Peninsula, we adopted a finite element tidal hydrodynamic simulation model, ADCIRC incorporating newly suggested dry-wet option and applied it to Chonbuk coastal area and Keum river estuary. Model comparison with observed current data by RMS error in the Chonbuk area shows very good agreement within 1cm/sec of tidal velocity difference and 3％ of error to maximum tidal currents. However there is not seen any significant advantages in dry-wet treatment. For the tidal volume tests in the Keum river estuary, the differences are satisfied within 5％ nevertheless of dry-wet treatment but in a near cross section it marks over 20％. However both results are almost same in tidal residual tests. Thus it can be concluded that dry-wet option is not always necessary in the simulation of long-term dispersion analysis.

• Journal of Navigation and Port Research
• /
• v.28 no.6
• /
• pp.565-572
• /
• 2004

Residual current plays more important role than the tidal current for long-term material transport in coastal areas. The main component of residual current is tide-induced residual current. Otherwise, wind driven current and buoyancy-driven current are important components which change the residual current. To clarify the characteristic of coastal current, application of a three -dimensional model is necessary. This study focuses on clarifying the stratified systems of coastal water affected by freshwater runoff from a river and analyzes the structure of current at Ulsan bay by applying a three-dimensional buoyancy-driven current model. According to the result of “Ulsan bay” study, it shows that the surface layer in semi-enclosed estuaries, which affected by freshwater runoff. has flows going out, and the bottom layer has flows coming in. Besides when the wind blows toward inside of the bay, the surface layer has flows coming in and the bottom layer has flows going out as compensation flows for the surface circulation. The results of simulation could be applicable to examine vertical upwelling, which might be caused by construction of artificial fishing reef to build aqua farm, submerged breakwater to control coastal sediment, and the formulation of oceanic ridge, or a basic study on application to the usage of deep water.

• Fisheries and Aquatic Sciences
• /
• v.13 no.2
• /
• pp.167-181
• /
• 2010

To predict changes in the marine environment of the Beolgyo Stream Estuary in Jeonnam Province, South Korea, where cohesive tidal flats cover a broad area and a large bridge is under construction, this study conducted numerical simulations involving tidal flow and cohesive sediment transport. A wetting and drying (WAD) technique for tidal flats from the Princeton Ocean Model (POM) was applied to a large-scale-grid hydrodynamic module capable of evaluating the flow resistance of structures. Derivation of the eddy viscosity coefficient for wakes created by structures was accomplished through the explicit use of shear velocity and Chezy's average velocity. Furthermore, various field observations, including of tide, tidal flow, suspended sediment concentrations, bottom sediments, and water depth, were performed to verify the model and obtain input data for it. In particular, geologic parameters related to the evaluation of settling velocity and critical shear stresses for erosion and deposition were observed, and numerical tests for the representation of suspended sediment concentrations were performed to determine proper values for the empirical coefficients in the sediment transport module. According to the simulation results, the velocity variation was particularly prominent around the piers in the tidal channel. Erosion occurred mainly along the tidal channels near the piers, where bridge structures reduced the flow cross section, creating strong flow. In contrast, in the rear area of the structure, where the flow was relatively weak due to the formation of eddies, deposition and moderated erosion were predicted. In estuaries and coastal waters, changes in the flow environment caused by artificial structures can produce changes in the sedimentary environment, which in turn can affect the local marine ecosystem. The numerical model proposed in this study will enable systematic prediction of changes to flow and sedimentary environments caused by the construction of artificial structures.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.11 no.1
• /
• pp.13-23
• /
• 2008

In coastal region, eutrophication, Do deficit and red tide are frequently occurred by influx of fresh water. When the fresh water containing pollutants is discharged into the sea, the surrounding water is contaminated by dispersion of freshwater flowing into coastal waters. The prediction and analysis about the dispersion process of the discharged fresh water should be conducted. A modeling system using GUI was developed to simulate hydrodynamic flow and fresh water dispersion in coastal waters and to analyze the results efficiently. The modeling module of the system includes a tide model using a finite element method and a fresh water dispersion model using a particle-tracking method. This system was applied to predict the tidal currents and fresh water dispersion in Mokpo coastal zone. To verify accuracy of the hydrodynamic model, the simulation results were compared with observed sea level and time variations of tidal currents showing a good agreement. The fresh water dispersion was verified with observed salinity distribution. The dispersion model also was verified with analytic solutions with advection-diffusion problems in 1-dimensional and 2-dimensional simple domain. The system is operated on GUI environment, to ease the model handling such as inputting data and displaying results. Therefore, anyone can use the system conveniently and observe easily and accurately the simulation results by using graphic functions included in the system. This system can be used widely to decrease the environmental disaster induced by inflow of fresh water into coastal waters.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.15 no.1
• /
• pp.39-50
• /
• 2003

This study aims to figure out water quality impacts due to sudden disturbances of sediments during dike construction in land reclamation for the northern part of the Siwhaho Lake where heavily deteriorated settlements from upstream loadings are outstanding. We exploit a 3-D water quality model CE-QUAL-ICM combined with a hydrodynamic model TIDE3D. Simulations are done accounting water-sediment interaction in a 4-$\sigma$ layers. Long-term simulation for 1-year shows that bottom layers around the disturbance location are only affected and marks very high concentration. Complete vertical mixing appears at least 5km apart to downward due to complex effects of geometry, bathymetry and river inflows. It should be addressed that existing condition of the Siwhaho Lake stands for high concentration of COD and TP in winter and spring due to relatively high incoming loadings, however the effect of sediment disturbances yields reverse phenomena, i.e., impacts of dike construction arise greatly in summer and fall. Refined grid system consisting of 150m${\times}$150m rectangular grid, which is doubled system compared to previous study (Suh et al.,2002), gives affordable results by reducing flux differences through a cell especially in front of gate.

• Journal of Digital Convergence
• /
• v.10 no.10
• /
• pp.129-137
• /
• 2012

Entering $21^{st}$ Century, the most critical keyword for companies is change and innovation. To achieve it, Obtaining right person becomes more and more important to those companies. It is not only supported by managers in business world but also by academia. However it is not easy to obtain right persons who have right experiences and knowledges. Therefore, the purpose of this study is to build strategic system which support help to hire and manage human resource. In this study, the suggested system is a type of strategic simulation game and job seeker can get several opportunities to be hired by joining the game. this system would help for companies to manage and hire right persons and there will be extra business opportunities. In conclusion, this system based on strategic simulation game would help human resource management and also promote job market and exchanging and trading companies' information and knowledge as well.