• Communications of the Korean Mathematical Society
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• v.27 no.2
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• pp.411-423
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• 2012

A nondifferentiable nonlinear semi-infinite programming problem is considered, where the functions involved are ${\eta}$-semidifferentiable type I-preinvex and related functions. Necessary and sufficient optimality conditions are obtained for a nondifferentiable nonlinear semi-in nite programming problem. Also, a Mond-Weir type dual and a general Mond-Weir type dual are formulated for the nondifferentiable semi-infinite programming problem and usual duality results are proved using the concepts of generalized semilocally type I-preinvex and related functions.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.38 no.1
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• pp.69-78
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• 2002

In order to examine the directional suitability of the axis direction of the fishing gear against the current, the experiments were carried out at the bamboo weir in Samchunpo water area from January, 2000 to September, 2001 The results of the study are as follows: In the experimental fishing gear constructed in the "V" shape, the range between two reference piles located at the entrance was 2.5m. The direction of bamboo weir′s axis was 355.5$^{\circ}$ The length of the left wing and those from the reference pile to the starting point of a curve were 106.0m, 7.5m, respectively. The length of the right wing and those from the reference pile to the starting point of a curve were 79.0m, 10.0m, respectively. Depths around the left and right stone wall that drove the steel pile were 5.0~6.5m and 6.5~9.5m, respectively. Also, depths on the bamboo weir′s axis and around the sack were 7.0~8.0m and about 8.0m, respectively. The maximum height of stone walls at the point of the left wing, the right wing and around the sack on the bamboo weir\` axis were 3.0m, 4.7m and 4.0m, respectively, Widths of stone walls at the point of both of the wings and around the sack on the bamboo weir\`s axis were 10.0~l4.0m, 22.0~25.0m, respectively. The averaging current direction on ebb tide was measured two times and it was 169.2$^{\circ}$ but the direction had about a 6.3$^{\circ}$ difference from the bamboo weirs axis. The maximum current speed appeared two to three hours later from the time of high tide and the current speed over 80.0cm/s lasted during about two Hours on the ebb tide In the case of a straight type wing In the bamboo weir, the eddy out of the left wing was comparatively big and the current on the right side from the bamboo weir′s axis had a tendency in turning to the right wing side. But in the case of a curve type wing, the eddy and tendency reduced significantly. It was thought that the experimental fishing gear was set suitably from the result of this simulation.

• Journal of Korean Society on Water Environment
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• v.26 no.2
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• pp.231-242
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• 2010

The objective of study was to determine an optimal location of a float-type curtain weir in Daecheong Reservoir and to assess its effectiveness for the control of algal blooms in the reservoir. CE-QUAL-W2, a laterally averaged two-dimensional hydrodynamic and eutrophication model, was modified to accommodate vertical displacement of the weir according to water surface fluctuation and applied to simulate the reservoir hydrodynamics and water quality changes for the reservoir. The model calibrated in a previous study was updated and validated for different hydrological conditions representing drought year (2008) and normal year (2006) for the study, and adequately simulated the temporal and spatial variations of water temperature, nutrients and algal (Chl-a) concentrations. The effectiveness of curtain weir on the control of algal bloom was evaluated by applying the validated model to 2001 and 2006 assuming 9 scenarios for different installation locations. The reduction rates of algal concentration were placed in the range of 11.2~40.3% and 20.3~56.7% for 2001 and 2006, respectively. Although, the performance of curtain weir was slightly varied for different locations and different hydrological years, overall, the performance was improved as the weir was installed further downstream.

• Journal of Korea Water Resources Association
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• v.36 no.6
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• pp.971-984
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• 2003

This paper presents the hydraulic analysis of the air entrainment by the weir types. For the weir types, the stepped weir, the labyrinth weir and the gate underflow weir were selected, and the oxygen transfer efficiency was estimated by the site investigation and the hydraulic model tests. The most effective type for the oxygen transfer was stepped weir The more steps the stepped weir had, the higher efficiency it revealed. Oxygen transfer was proportional to the flow velocity, the Froude number, and the flow discharge in order. Hydraulic model tests showed that a nappe flow occurred at small flow rates. The concurrent condition of a nappe flow and a skimming flow occurred as flow rate increases, nappe flow at the upper part and skimming flow at the lower part. In the region of nappe flow, air inception occurred from the step edges due to flow separation, and air entrainment was made through a free-falling nappe, an air pocket, a nappe impact and a subsequent hydraulic jump. In the region of skimming flow, air entrainment occurred by the variation of water surface over the steps, but it was relatively small compared with nappe flow.

• Journal of Korea Water Resources Association
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• v.48 no.8
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• pp.673-683
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• 2015

The existing flood protection in rivers has shown the limitation due to the urbanization around rivers and the abnormal climate. Thus, the demand for the constructions of side-weir detention basin are being increased as a part of integrated watershed flood protection plan. It is necessary to estimate the quantitative flood-control effect for including the side-weir detention basin in flood-control measures. For the determination, it is required to reduce the uncertainty of the design factors which can affect the flood-control effect of side-weir detention basin. Among the factors, however, the water level in river always contains uncertainty. Therefore, the design method considering the uncertainty is required. For the reasons, the design method considering uncertainty of the water level in river is suggested in this study with using the length of side-weir which is relatively easy-determinable by designers. Therefore, it is examined how the variation of the length of side-weir can affect the flood-control effect, using HEC-RAS, and then the method to determine the side-weir length considering the uncertainty of the water level in river through results from analyses. Since the uncertainty of the water level in river can be taken into account in the suggested design method, it is evaluated that the design method is more effective to suggest the flood-control effect of the side-weir type detention basin with higher safety side.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.5
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• pp.1841-1850
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• 2013

The various types of fishways are installed at the multi-functional weirs in the four major rivers to minimize the negative effect due to the construction of the transverse structures. The movable weir was installed at the upstream of the ice-harbor type artificial fishway of the Dalseong weir in the Nakdong river, which can control the fishway flowrate regardless of the river flowrate. The incoming flowrate to the artificial fishway is closely related with the hydraulic characteristics that dominate the fish passage efficiency. Thus, it is crucial to find out the weir operation rule for properly sustaining efficient fish-passage, such as the optimized flowrate. In this study, the FLOW-3D was used to analyze and compare the various hydraulic characteristics associated with the passage efficiency, based upon the given different flowrate, and subsequently provide the optimized flowrate for the fishway movable weir to maintain the best efficient flow condition for the fish-passage.

• Communications of the Korean Mathematical Society
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• v.19 no.1
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• pp.179-196
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• 2004

Mond-Weir type duals for multiobjective variational problems are formulated. Under generalized vector variational type I invexity assumptions on the functions involved, sufficient optimality conditions, weak and strong duality theorems are proved efficient and properly efficient solutions of the primal and dual problems.

• Journal of Korea Water Resources Association
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• v.40 no.2 s.175
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• pp.135-146
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• 2007

FLDWAV model was modified such that it can adequately simulate the effect of Jamsil and Singok submerged weirs in the main reach of the Han River. The enhanced model combines weir-type discharge equations for overflow at fixed weir and Manning equation for fluvial-type flow at the movable weir. Equations for weir overflow include those for submerged weir flow and free overflow. Gates of the movable weir may be open or closed for the simulation. In order to test the simulation capabilities, the enhanced model was applied for various flow conditions at submerged weirs. Backwater effect due to Jamsil and Singok submerged weirs were well simulated. Simulations were carried out for spring and neap tides extracted from artificial tide generated by combining $M_2\;and\;S_2$ tidal constituents. Simulation results cleared indicated that tidal effect extends further upstream as the flood discharge decreases. Low flow simulation capabilities of the enhanced model was tested. Discontinuities of water surface elevation due to the submerged weirs were successively simulated.

• Journal of applied mathematics & informatics
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• v.10 no.1_2
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• pp.83-99
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• 2002

Optimality conditions are derived for a nonlinear program in which a support function appears in the objective as well as in each constraint function. Wolfe and Mond-Weir type duals to this program are presented and various duality results are established under suitable convexity and generalized convexity assumptions. Special cases that often occur in the literature are those in which a support function is the square root of a positive semi- definite quadratic form or an Lp norm. It is pointed out that these special cases can easily be generated from our results.

• Journal of Wetlands Research
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• v.15 no.4
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• pp.573-583
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• 2013

Construction of large-scale structures such as dams would be suggested actively to cope with change of flood characteristics caused by climate change. However, due to environmental, economic and political issues, dams are not ideally constructed. Thus flood damage reduction planning projects would get started including washland or detention pond for sharing the flood in basin. The washland made artificially by human being is an area of floodplain surrounded by bank to be intentionally inundated by overflowing through overflow structure adjacent to main channel during flood season. Flood reduction capacity at just downstream of each washland could be affected by type, length, and crest elevation of overflow structure in addition to shape of design hydrograph, storage volume of washland, etc.. In this study flood reduction effects of washland are estimated for overflow weir type and gate type to compare the results of flood reduction respectively subjected to given hydrograph in sample site, the Cheongmicheon stream. It has been shown that even if gate type at overflow structure could yield more flood reduction than overflow weir type, economic aspect such as initial cost, operation cost and maintenance cost should be considered to select the type of overflow structure because flood reduction rate by gate type could not be significant value from engineering point of view.