• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.1B
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• pp.47-55
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• 2011

This study suggests new synthetic unit hydrograph method considering hydrodynamic characteristic on the basin. The suggested method based on width function GIUH, and the procedure is summarized as follows; 1) Draw up a travel distance distribution map (width function) which is raster of length between from center of individual cells to the outlet by GIS. 2) Calculation of travel time distribution map (rescaled width function) by hydrodynamic parameters and travel distance distribution map. 3) Derivation of IUH and Duration UH from rescaled width function. 4) Comparison of shape of UH between suggested method and existing synthetic unit hydrograph methods. The target basins are selected Ipyeong and Tanbu subwatershed in the Bocheong Basin. The target basins are similar scale (watershed area), but different drainage structure (drainage density et al.). Therefore we anticipate that there are different hydrologic response functions because different hydrodynamic characteristics. As a result of derivation of UH, existing synthetic unit hydrograph methods are similar shape of UHs about Ipyeong and Tanbu watersheds, but the suggested method is different shape of ones. As a result of application to observed data, the peak discharge by suggested method is similar to existing synthetic unit hydrograph methods, but the peak time is well correspondence between those. Henceforth, if the suggested method combines with the rational velocity estimation method, it is useful method for synthetic of UH in ungauged watershed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.04a
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• pp.108-108
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• 2009

The main object of this research is to minimize the shock effects which frequently result in fatal damage in wind met mast on impact of barge. The collision between wind met mast and barge is generally a complex problem and it is often not practical to perform rigorous finite element analyses to include all effects and sequences during the collision. LS-dyna generally purpose explicit finite element code, which is a product of ANSYS software, is used to model and analyze the non-linear response of the met mast due to barge collision. A significant part of the collision energy is dissipated as strain energy and except for global deformation modes, the contribution from elastic straining can normally be neglected. On applying impact force of a barge to wind met mast, the maximum acceleration, internal energy and plastic strain were calculated for each load cases using the finite element method and then compare it, varying to the velocity of barge, with one varying to the thickness of rubber fender conditions. Hence, we restrict the present research mainly to the wind met mast and also parametric study has been carried out with various velocities of barge, thickness of wind met mast, thickness and Mooney-Rivlin coefficient of rubber fender with experimental data. The equation of motion of the wind met mast is derived under the assumption that it was ignored vertical movement effect of barge on sea water. Such an analyzing method which was developed so far, make it possible to determine the proper size and material properties of rubber fender and the optimal moving conditions of barge, and finally, application method can be suggested in designing process of rubber fender considering barge impact.

• 한국해양학회지
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• v.29 no.3
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• pp.296-303
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• 1994

Rotating right cylinder of rigid sloping boundaries(top-bottom) is filled with two-layered fluid. External fluid which has the same density as the lower-layer is pumped through the rim boundary at the bottom, and this induces uniform vertical velocity in the interior that produces the Sverdrup type motion such as southward flowing western boundary current with northward interior horizontal motion. The rigid sloping upper boundary meets with lower layer to simulate so called "polar front", and the upper-layer motion influenced by the lower-layer flow has been observed. Barotropic motion in the western part of the basin while baroclinic motion in the eastern half is always present. In particular, both southward flowing eastern boundary flow and western boundary flow meets near the western wall and it induces northward western boundary flow to separate from the boundary With increased ${\beta}$-effect on the upper0layer the width of western boundary decreases and the separated western boundary flow moves into the interior to form an eddy-like motion. Baroclinic Rosebay wave clearly observed in the easter boundary slowly propagates to the west but it seems to be decayed before travelling to the western boundary. A local topograpic effect imposed on the lower-layer causes very sensitive response of upper layer boundary flows. In the east standing0wave0like features are observed in the west whereas the width of the boundary increases without any evidence of the separation of the western boundary flow.This may be due to the gact that even the lower-lauer barotropic motion feels the topography its influence does not propagate into the upper-layer. With large ${\beta}$-effect on the upper-layer,relatively large scale waves whose wavelengths are greater than the internal radius deformation exist in the interior.

• Korean Journal of Environmental Biology
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• v.34 no.2
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• pp.116-123
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• 2016

The ecotoxicity tests for metal plating wastewater were conducted using Daphnia magna (D. magna) and Euglena agilis (E. agilis). Evaluation for sources of toxicity was performed by 1) Correlation analysis between the concentration of individual metals in the metal plating wastewater and the toxic effects on D. magna, 2) Toxicant identification evaluation methods including graduated pH method, EDTA procedure and sodium thiosulfate procedure, 3) Comparison of toxic effect value ($EC_{50}$ or $LC_{50}$) of individual metal on D. magna and it's concentration in the metal plating wastewater. To evaluate the possibility of E. agilis, a Korean domestic organism, as a test model organism for metal plating waste water, E. agilis toxicity test was also assessed using on-line euglena ecotoxicity system (E-Tox system). Based on toxicant characterization test using D. magna, it was expected that SS, oxidants and heavy metals are responsible for toxicity of metal plating waste water. Especially Cu, Hg, and Ag were the major cationic metals that caused toxicity. E. agilis is less sensitive than D. magna based on the $EC_{50}$ value however it shows prompt response to toxic test substances. E. agilis shows even a significant effect on the cell swimming velocity within 2 min to toxic metal plating wastewater. Our study demonstrates that E. agilis test can be a putative ecotoxicity test for assessing the quality of metal plating waste water.

• Journal of the Korean Society of Clothing and Textiles
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• v.16 no.4 s.44
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• pp.405-416
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• 1992

This study was performed to investigate correlation between total body weight loss and local sweat rate and to find out any possible method that can estimate total body weight loss judging from local sweat rate. Twelve adult females were kept at 44 $\pm1^{\circ}C$, 50 ${\pm}5\%$ R.H. (1) Physiological responses such as total body weight loss, local sweat rate, rectal temperature, skin temperature, blood pressure and pulse, (2) micro climate inside garment and (3) subjective sensation were examined. Two types of garment such as long-sleeves with long pants (Type I) and half·sleeves with short pants (Type II) were used to observe the effect of garment types on sweating response. Both clothing weight was equal (132$\pm$3 g/$m^{2}$). The results were as follows: 1. Regardless of the different types, total body weight loss was more interrelated with the sweat rate on forehead than any other parts of the body. Except the forehead, different parts of body with different types of garment influenced on body weight loss quite differently. 2. Total body weight loss was more interrelated with the weight gain of garment than the local sweat rate. 3. Under the environment of 44$\pm1^{\circ}C,\;50{\pm}5\%$R.H., body weight loss during 1 hour of subject clothed and silted was 275.2 g/hr and weight loss per body surface area was 178.9 g/$m^{2}/hr$ Garment types have no influences on total body weight loss. 4. Local sweat rate (mg/7.07 $cm^{2}/hr$) was 208.0,191.0, 133.0, 115.0,81 0, 75.1 and 66.3 on scruff, breast, forehead, forearm, thigh, upper arm, leg respectively No evidence has been found that garment types influenced on local sweat rate (p<0.1). 5. No interrelationships between rectal temperature and total body weight loss, local skin temperature and total body weight loss, and local skin temperature and local sweat rate were found. From this study, some possible method that we can estimate total body' weight loss judging from weight loss of garment. But considering the fact that clothing design factor, the physical characteristics of fabric and environmental factor such as humidity and wind velocity should be concerned in weight loss of garment, it should be studied further whether the total body weight loss can be estimated properly from the weight loss of garment. This experiment suggest that different parts of body with different types of garment can influence on body weight loss quite differently. Therefore, in order to get more precise results, more studies under the diversity of garment types should be done in the near future.

• Journal of the Korean Association of Geographic Information Studies
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• v.11 no.2
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• pp.38-50
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• 2008

The site-specific seismic responses and corresponding seismic hazards are influenced mainly by the subsurface geologic and geotechnical dynamic characteristics. To estimate reliably the seismic responses in this study, a geotechnical information system (GTIS) within GIS framework was developed by introducing new concepts, which consist of the extended area containing the study area and the additional site visit for acquiring surface geo-knowledge data. The GIS-based GTIS was built for Gyeongju area, which has records of abundant historical seismic hazards reflecting the high potential of future earthquakes. At the study area, Gyeongju, intensive site investigations and pre-existing geotechnical data collections were performed and the site visits were additionally carried out for assessing geotechnical characteristics and shear wave velocity ($V_S$) representing dynamic property. Within the GTIS for Gyeongju area, the spatially distributed geotechnical layers and $V_S$ in the entire study area were reliably predicted from the site investigation data using the geostatistical kriging method. Based on the spatial geotechnical layers and $V_S$ predicted within the GTIS, a seismic zoning map on site period ($T_G$) from which the site-specific seismic responses according to the site effects can be estimated was created across the study area of Gyeongju. The spatial $T_G$ map at Gyeongju indicated seismic vulnerability of two- to five-storied buildings. In this study, the seismic zonation based on $T_G$ within the GIS-based GTIS was presented as regional efficient strategy for seismic hazard prediction and mitigation.

• International Journal of Highway Engineering
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• v.2 no.1
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• pp.135-145
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• 2000

A new procedure needs to be developed to predict the dynamic layer properties under moving truck loads. In this study, a computer code to evaluate layer moduli of asphalt concrete pavement from measured interior deflections at various depths were developed and verified from numerical model tests. Interior deflections of the pavement are measured from Multi-Depth Deflectometer(MDD). It was found that errors between the given and backcalculated moduli in numerical analysis were less than 0.32% for several numerical models tested. When impact loads were used, a technique to determine the depth to virtual rigid base was proposed through the analysis of compressive wave velocity and impulse loading durations. It was found that errors between the given and backcalculated moduli in numerical analysis were less than 0.114% when virtual rigid base was considered in numerical analysis. The pavement behavior must be evaluated under various vehicle speeds when determining the dynamic interaction between the loading vehicle and pavement system. To evaluate the dynamic behavior on asphalt concrete pavement under various vehicle speeds, truck moving tests were carried out. From the test results with respect to vehicle speed, it was found that the vehicle speed had significant effect on actual response of the pavement system. The lower vehicle speed generates the higher interior deflections, and the lower dynamic modulus.

• Ecology and Resilient Infrastructure
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• v.3 no.2
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• pp.134-142
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• 2016

Temperature increase and precipitation changes caused by change alter aquatic environments including water quantity and quality that eventually affects the habitat of aquatic organisms. Such changes in habitat lead to changes in habitat suitability of the organisms, which eventually determines species distribution. Therefore, conventional habitat suitability models were investigated to evaluate habitat suitability changes of freshwater fish cause by change. Habitat suitability models can be divided into habitat-hydraulic (PHABSIM, CCHE2D, CASiMiR, RHABSIM, RHYHABSIM, and River2D) and habitat-physiologic (CLIMEX) models. Habitat-hydraulic models use hydraulic variables (velocity, depth, substrate) to assess habitat suitability, but lack the ability to evaluate the effect of water quality, including temperature. On the contrary, CLIMEX evaluates the physiological response against climatic variables, but lacks the ability to interpret the effects of physical habitat (hydraulic variables). A new concept of ecological habitat suitability modeling (EHSM) is proposed to overcome such limitations by combining the habitat-hydraulic model (PHABSIM) and the habitat-physiologic model (CLIMEX), which is able to evaluate the effect of more environmental variables than each conventional model. This model is expected to predict fish habitat suitability according to climate change more accurately.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.1
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• pp.200-214
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• 1993

This paper presents the results of fluidelastic instability analysis performed for the U-tube bundle of a Westinghouse model 51 steam generator, one of the recirculating types designed at an early stage, in which the principal region of external cross-flow is associated with the U-bend portion of tube. The prerequisites for this analysis are detailed informations of the secondary side flow conditions in the steam generator and the free vibration behaviours of the U-tubes. In this study, the three-dimensional two-phase flow field in the steam generator has been calculated employing the ATHOS3 steam generator two-phase flow code and the ANSYS engineering analysis code has been used to calculate the free vibration responses of specific U tubes under consideration. The assessment of the potential instability for the suspect U-tubes, which is the final analysis process of the present work, has been accomplished by combining the secondary side velocity and density distributions obtained from the ATHOS3 prediction with the relative modal displacement and natural frequency data calculated using the ANSYS code. The damping of tubes in two-phase flow has been deduced from the existing experimental data by taking into account the secondary side void fraction effect. In operation of the steam generator, the tube support conditions at the tube-to-tube support plate intersections due to either tube denting degradation or deposition of tube support plate corrosion products or ingression of dregs. Thus, various hypothetical cases regarding the tube support conditions at the tube-to-tube support plate intersections have been considered to investigate the clamped support effects on the forced vibration response of the tube. Also, the effect of anti-vibration bars support in the curved portion of tube has been examined.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.37 no.2
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• pp.78-84
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• 2001

Escape behaviour of the anchovy (Engralius japonica, total length 4-7cm) at the inside wing net and bag net in the anchovy boat seine was observed by underwater video camera in order to clarify the relationship between visual stimulus of the gear or relative water flow inside gear and reacting behaviour. The vertical attenuation coefficient of underwater illuminance in the offshore of Keoje island and Tongyoung was ranged from 0.24 to 1.03 and it could be affect visual range and visual contrast of the fishing gear. The relative water flow at the joint part between inside wing and bagnet while towing was 1.5 times higher than at the middle part of inside wing or fore part of bag net, but it was estimated under than maximum swimming speed of 4-7 cm anchovy. The mean escaping number of anchovy from end part of inside wing of 30 cm mesh to out side for a minute within visual range of video camera was 455 and anchovy swimming forward from bag net through flapper was 308. These results revealed anchovy could escape as voluntary response in spite of higher visual stimulus or higher water flow.