• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.52 no.2
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• pp.88-95
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• 2016

Most grid sorting has been used to sort out flatfish in shrimp fisheries, while double grid systems have been tested to separate smaller shrimp. The escape of juvenile red seabream through separating panels made with steel grids or large mesh tested for masking effects in a two-species system. Fish behavior was observed in a circulating water tank. The escape rate was 20% greater with the separating codends than with the normal codend in the single-species experiments. The rates in the two-species experiments were 30% or 20% greater than the single-species rates for the normal or separating codends, respectively. The seabream retention rates in the grid separator codend decreased as rockfish retention increased, possibly due to a threat effect. Conversely, the retention rate of both species increased concurrently in the net separator, possibly due to a masking effect. The escape rates of juvenile red seabream varied by compartment in the mesh separating codend. These results suggest that grid separating codends can be used in the field as towed fishing gear to reduce juvenile catch.

• Journal of the Chungcheong Mathematical Society
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• v.25 no.3
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• pp.563-577
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• 2012

This paper presents a moving mesh method for solving the hyperbolic conservation laws. Moving mesh method consists of two independent parts: PDE evolution and mesh- redistribution. We compute numerical solution of shallow water equation by using moving mesh methods. In comparison with computations on a fixed grid, the moving mesh method appears more accurate resolution of discontinuities.

• Journal of Technologic Dentistry
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• v.28 no.1
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• pp.9-17
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• 2006

The purpose of this study was to evaluate the titanium castability with a spin type casting machine(TiCast, Super R, Selec, Osaka. Japan). We tested phosphate bonded investment "Rematitan$^{(R)}$Plus(Dentaurum, Inc., Pforzheim, Germany)"of mesh grid pattern and plate pattern. Four different mold temperatures(room temperature, 200$^{\circ}C$, 400$^{\circ}C$ and 600$^{\circ}C$) were prepared for the present study. In mesh grid pattern with spruing of $\varphi$0.88㎜ dimeter, when the mold temperature increased, high percentage of castability was gained. Mold temperature showed a highly significant(p<0.05) correlation on the castability, In plate pattern, the higher the mold temperature during casting, the greater the adhesive phenomenon between Ti surface and the investment.

• Nuclear Engineering and Technology
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• v.51 no.8
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• pp.1905-1915
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• 2019

This paper investigated the influence of simple support girds on flow, irrespective of having mixing vanes, in a 1 × 3 array rod bundle by using CFD methodology and the most accurate turbulence model which could reflect the actual physics of the flow was determined. In this context, a CFD model was created simulating the experimental studies on a single-phase flow [1] and the results were compared with the experimental data. In the first part of the study, influence of mesh was examined. Tetra, hybrid and poly type meshes were analyzed and convergence study was carried out on each in order to determine the most appropriate type and density. k - ε Standard and RSM LPS turbulence models were used in this section. In the second part of the study, the most appropriate turbulence model that could reflect the physics of the actual flow was investigated. RANS based turbulence models were examined using the mesh that was determined in the first part. Velocity and turbulence intensity results obtained on the upstream and downstream of the spacer grid at -3d_h, +3d_h and +40d_h locations were compared with the experimental data. In the last section of the study, the behavior of flow through the spacer grid was examined and its prominent aspects were highlighted on the most appropriate turbulence model determined in the second part. Results of the study revealed the importance of mesh type. Hybrid mesh having the largest number of structured elements performed remarkably better than the other two on results. While comparisons of numerical and experimental results showed an overall agreement within all turbulence models, RSM LPS presented better results than the others. Lastly, physical appearance of the flow through spacer grids revealed that springs has more influence on flow than dimples and induces transient flow behaviors. As a result, flow through a simple support grid was examined and the most appropriate turbulence model reflecting the actual physics of the flow was determined.

• 한국전산유체공학회:학술대회논문집
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• 1998.11a
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• pp.19-22
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• 1998

Automatic mesh generation procedures applied to industrial now problems lead to complex mesh topologies where usually no special considerations to mesh resolution are taken. In the present study a fast and flexible solution algorithm in combination with generalized higher order discretization schemes is presented and its application to intake port calculation is demonstrated.

• 한국전산유체공학회:학술대회논문집
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• 2003.10a
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• pp.86-87
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• 2003

Unstructured grid system is suitable for flows of complex geometries. For problems with moving boundary walls, the grid system must be changed and deformed with time if we use a body fitted grid system. In this paper, a new moving-grid finite-volume method on unstructured grid system is proposed and developed for unsteady compressible flows with shock waves. To assure geometric conservation laws on moving grid system, a control volume on the space-time unified domain is adopted for estimating numerical flux. The method is described and applied for two-dimensional flows.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.1264-1266
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• 2009

We introduce a location-based routing model applied for grid backbone nodes in wireless mesh network. The number of paths with nearest distance between two nodes is calculated and used as key parameter to execute routing algorithm. Node will increase the transmission range that makes a trade off with data rate to reach its neighbors when node itself is isolated. The routing model is lightweight and oriented thanks to the simple but efficient routing algorithm.

• Analytical Science and Technology
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• v.14 no.6
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• pp.486-493
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• 2001

The effect of SIMS analysis conditions such as mesh grid, offset voltage and ion species on the in-depth profile for bismuth titanate thin film was examined in terms of charging effect and detection limit. The results shows that the use of offset voltage -40 V reduces the charging effect and the detection limit. The employment of mesh grid in sample preparation leads to the reduction of the charging effect in small amount, but deteriorate the detection limit. Utilization of primary $O^-$ ion for SIMS analysis of bismuth titanate thin film showed almost the same effect as using offset voltage -40 V. However, it takes approximately triple acquisition time than using $O_2{^+}$ ion due to the poor beam current of the source in the experiment.

• Journal of Korea Water Resources Association
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• v.51 no.10
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• pp.853-862
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• 2018

An adaptive cut-cell grid based 2D inundation analysis model, K-Flood, is developed in this study. Cut cell grid method divides a grid into a flow area and a non-flow area depending the characteristics of the flows. With adaptive mesh refinement technique cut cell method can represent complex flow area using relatively small number of cells. In recent years, the urban inundation modeling using high resolution and fine quality data is increasing to achieve more accurate flood analysis or flood forecasting. K-Flood has potential to simulate such complex urban inundation using efficient grid generation technique. A finite volume numerical scheme of second order accuracy for space and time was applied. For verification of K-Flood, 1) shockwave reflex simulation by circular cylinder, 2) urban flood experiment simulation, 3) Malpasset dam collapse simulation are performed and the results are compared with observed data and previous simulation results.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.3 s.234
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• pp.447-454
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• 2005

This paper presents a new paradigm for 3-axis tool path generation based on an incomplete 2-manifold mesh model, namely, an inexact polyhedron. When geometric data is transferred from one system to another system and tessellated for tool path generation, the model does not have any topological data between meshes and facets. In contrast to the existing polyhedral machining approach, the proposed method generates tool paths from an incomplete 2-manifold mesh model. In order to generate gouge-free tool paths, CL-meshes are generated by offsetting boundary edges, boundary vertices, and facets. The CL-meshes are sliced by machining planes and the calculated intersections are sorted, trimmed, and linked. The grid method is used to reduce the computing time when range searching problems arise. The method is fully implemented and verified by machining an incomplete 2-manifold mesh model.