• Journal of the Korean Mathematical Society
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• v.51 no.2
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• pp.267-288
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• 2014

We propose and analyze two-scale product approximation for semilinear heat equations in the mixed finite element method. In order to efficiently resolve nonlinear algebraic equations resulting from the mixed method for semilinear parabolic problems, we treat the nonlinear terms using some interpolation operator and exploit a two-scale grid algorithm. With this scheme, the nonlinear problem is reduced to a linear problem on a fine scale mesh without losing overall accuracy of the final system. We derive optimal order $L^{\infty}((0, T];L^2({\Omega}))$-error estimates for the relevant variables. Numerical results are presented to support the theory developed in this paper.

• Structural Engineering and Mechanics
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• v.5 no.1
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• pp.69-83
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• 1997

A new efficient hybrid/mixed thin~moderately thick plate bending element with 6-node (HM6-14) is formulated based on the Reissner-Mindlin plate bending theory. The convergence of this element is proved by error estimate theories and verified by patch test respectively. Numerical studies on such an element as HM6-14 demonstrate that it has remarkable convergence, invariability to geometric distorted mesh situations, to axial rotations, and to node positions, and no "locking" phenomenon in thin plate limit. The present element is suitable to many kinds of shape and thin~moderately thick plate bending problems. Further, in comparison with original hybrid/mixed plate bending element HP4, the present element yields an improvement of solutions. Therefore, it is an efficient element and suitable for the development of adaptive multi-field finite element method (FEM).

• Journal of Korea Water Resources Association
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• v.44 no.2
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• pp.109-123
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• 2011

In this study, 2D finite volume model, which can apply to the mixed meshes that is effective to treat the complicated topography such as a natural river, is developed. To do so, an algorithm for finding the neighbouring cell of a computational cell is introduced, and fluxes are computed using the HLLC approximate Riemann solver at each interface between a computational cell and it's neighbouring cells. Moreover, in order to numerically treat the bed slope which has important effect on the balance between flux gradients and sourte terms, different formula to compute the bed slope for rectangular and triangular mesh are applied. The developed model is applied to analyze dam-break in an experimental channel with $90^{\circ}$ bend and Malpasset dam-break in France. The two cases consist of mixed meshes and the suggested method is validated for the experimental channel and natural channel by comparison with the experimental data, field data and computed results.

• Korean journal of food and cookery science
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• v.7 no.2
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• pp.75-80
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• 1991

Millet Nochi is a kind of Korean traditional food which is not well known to the general public. This study was crried out in order to elucidate the cooking method and investigate the changes of textural properties during retrogradation. Cooking method for millet Nochi were as follows. 1. Millet is soaked in water for 3 hours, mashed, sifted by 20 mesh 3 screen. 2. The millet flour is mixed with malt (amount of malt is 0.025 times of millet flour by weight) 3. This mixture is steamed for 20 minutes. 4. Steamed mixture is again mixed with the same amount (0.025 times of millet by weight) of malt. 5. The mixture is incubated at $60^{\circ}C$ for 2 hours. 6. After incubation, the mixture is panfried. 7. The changes of textural properties during 30 freeze-thaw cycles, except adhesiveness were not significantly appeared.

• Structural Engineering and Mechanics
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• v.35 no.3
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• pp.283-299
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• 2010

This paper addresses the numerical simulation of fatigue crack growth in arbitrary 2D geometries under constant amplitude loading by the using a new finite element software. The purpose of this software is on the determination of 2D crack paths and surfaces as well as on the evaluation of components Lifetimes as a part of the damage tolerant assessment. Throughout the simulation of fatigue crack propagation an automatic adaptive mesh is carried out in the vicinity of the crack front nodes and in the elements which represent the higher stresses distribution. The fatigue crack direction and the corresponding stress-intensity factors are estimated at each small crack increment by employing the displacement extrapolation technique under facilitation of singular crack tip elements. The propagation is modeled by successive linear extensions, which are determined by the stress intensity factors under linear elastic fracture mechanics (LEFM) assumption. The stress intensity factors range history must be recorded along the small crack increments. Upon completion of the stress intensity factors range history recording, fatigue crack propagation life of the examined specimen is predicted. A consistent transfer algorithm and a crack relaxation method are proposed and implemented for this purpose. Verification of the predicted fatigue life is validated with relevant experimental data and numerical results obtained by other researchers. The comparisons show that the program is capable of demonstrating the fatigue life prediction results as well as the fatigue crack path satisfactorily.

• Journal of Animal Science and Technology
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• v.44 no.1
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• pp.75-86
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• 2002

Adequate forage amounts in ruminant animal are necessary for proper ruminal function in dairy cow. This study was carried out to determine the effect of total mixed fermentation feeds made by different green forage crops and grain processings on chemical compositions, RFV (relative feed value) and ruminal characteristics in sheep. The experiment was arranged in a split plot design with 4 replications. The main plot consisted of 6 kinds of green forages (corn, grass, rye, rape, alfalfa and oat) and the sub plots three different grain processings such as non-milling, half milling (7mm mesh over), and regular milling (7mm mesh below). And the different TMFFs (total mixed fermentation feeds) were analyzed for chemical composition and fed to 8 ruminally fistulated sheep for ruminal charactics and palatability. RFV, daily feed intake, acetate/propionate ratio of the rape-TMFFs were higher compared with the other treatment. Ruminal content of VFA (volatile fatty acid) of corn-TMFF was highest as 90.19 mmol% and pH of the feed was lowest as 3.82. But, acetic acid, propionic acid and butyric acid were no difference among treatments. In conclusion, the effect of grain proceeding was not appeared but if consider of only RFV, palatability and dry matter disappearance, grade of TMFF was improved in order of rape-, corn-, alfalfa-, grass-, oat- and rye-TMFF.

• 한국전산유체공학회:학술대회논문집
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• 2005.10a
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• pp.213-217
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• 2005

In this study the water including sediment is assumed that the density is different from fresh water. And the phenomenon inhaled by low pressure around the pipe is numerically simulated in two dimension. The simulation is done using finite difference method in rectangular staggered mesh system and Navier-Stokes equations and continuty equation are employed as governing equations. The method of Irregular leg lengths and stars are adopted to satisfy boundary condition of body boundary. Marker-Density method is used to calculate the density of mixed flow. Also SGS turbulence model is applied to consider vortex smaller then grid at high Renolds number. This study is to analyze inhalation phenomenon of mixed flow with sediment and to verify the numerical method for mixed flow. To verify the numerical results are compared with experimental results

• Journal of Communications and Networks
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• v.10 no.3
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• pp.331-337
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• 2008

In this paper, we investigate survivability in wavelength division multiplexing (WDM) mesh networks and propose a new algorithm called improved shared-path protection (ISPP) to completely tolerate the double-link failures. Compared with previous algorithms for protecting double-link failures, i.e., shared-path protection (SPP) and shared-link protection (SLP), the advantage of ISPP is to allow primary paths and backup paths to share the mixed wavelength-links based on the proposed new rules in which some primary wavelength-links can be changed to mixed wavelength-links, which can be shared by primary paths and backup paths. In addition, some mixed wavelength-links also can be shared by different backup paths for saving resources. Simulation results show that ISPP algorithm performs better in resource utilization ratio and blocking probability than conventional SPP and SLP algorithms.

• Structural Engineering and Mechanics
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• v.4 no.2
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• pp.191-202
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• 1996

This paper presents a construction of adaptive boundary element for the problem with mixed boundary conditions such as heat transfer between heated body surface and surrounding medium. The scheme is based on the sample point error analysis and on the extended error indicator, proposed earlier by the authors for the potential and elastostatic problems, and extended successfully to multidomain and thermoelastic analyses. Since the field variable is connected with its derivative on the boundary, their errors are also interconnected by the specified condition. The extended error indicator on each boundary element is modified to meet with the situation. Two numerical examples are shown to indicate the differences due to the prescribed boundary conditions.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.7
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• pp.51-58
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• 2010

Wireless Mesh Network has drawn much attention due to wide area service coverage with low system cost. However, there is a bottleneck problem in wireless mesh network since the traffic is aggregated into a gateway. Placement of multi-radio can easy the bottleneck problem, but without careful design it results in unnecessary system cost increasement. In this paper, we propose a system cost minimization through differential antenna placement where optimum antenna placement is determined by the required wireless link capacity. With CPLEX program, optimum number of antennae is determined as a function of local user traffic and gateway capacity. From numerical analysis, it is confirmed that our proposed model can solve bottleneck problem, and at the same time save the system cost.