• The Journal of the Korea Contents Association
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• v.4 no.2
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• pp.7-12
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• 2004

The technique of birdeye image generation of terrain through the use of satellite digital images and digital maps are very important elements and have applications in fanning establishment as well as the actual design of several construction works in complex fields. This paper studies stereo perspective image generation as a possibility through 3-dimensional analysis combined with digital elevation data and remotely sensed images. For this, first of all, ortho-images generated by very accurate GCP and DEM from contour file makes 3-dimensional terrain analysis possible and allows stereo­viewing at the highway construction planning sites. So, we developed the technical methods for the 3-dimensional approach on the planning sites of highways by use of perspective orthoimages. From this research, diverse terrain analysis is possible through stereo perspective image generation, and can leads to various application in road construction through gain study results from access to realtime virtual spatial on the objects area in korea.

• Journal of Korea Water Resources Association
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• v.31 no.4
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• pp.491-501
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• 1998

Numerical simulations were performed to analyse the flow pattern of the approach channel and to design the spillway guidewall for stable flow conditions. RMA-2, two dimensional finite element model which can easily represent complicated geometry was used, and model parameters were estimated from the observation data of hydraulic model test. Numerical experiments were made separately for the approach region and for the upstream region, and upstream boundary position of the hydraulic model beyond which the boundary effects are negligible was determined from the numerical results. For the stable flow condition in approach channel, alternative designs for guidewall were developed, and flow analysis for alternative designs was done through the numerical simulation. From the analysis of alternative design, we can see that the flow pattern in the approach channel is stable and the lateral stage difference disappears mostly before the spillway crest.

• Journal of Korea Water Resources Association
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• v.31 no.6
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• pp.675-684
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• 1998

This paper presents the empirical formulas for determining the design-width for medium rivers in the Han river basin. The design flood, the watershed ares, and the channel slope of 216 medium rivers in the Han river basin are collected. the design width formulas are then determined by 1) the least squares (LS) method, 2)the least median squares (LMS) method, and 3) the reweighted least squares method based on the LMS (RLS). The six types of formulas are considered to determine the acceptable type for medium streams in the Han river basin. The root mean squared errors (RMSE), the absolute mean (AME) errors, and the mean errors (ME) are computed to test the formulas derived by three regression methods. It si found that the equation related stream width to the watershed area and the channel slope is acceptable for determining the design width for medium streams in the Han river basin. It is expected that the equations proposed by this study be used an index for determining the design-width for medium streams in the Han river basin.

• Proceedings of the Korean Society of Environment and Ecology Conference
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• 2006.10a
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• pp.86-96
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• 2006

To provide some ecological informations for protection and management of mixed heronries, their distribution, breeding species and individuals, and site characteristics that may be important to heron ecology were investigated in Jeollanam-do during 2005 breeding season. During the study, 17 mixed heronries, containing a total of six ardeid species were found. Of them, Great Egret(Egretta alba) and Grey Heron(Ardea cinerea) bred in most sites(both 92%) and were most numerous(36.3%, 31.0% respectively). Many of heronries(53.3%) were located within the bamboo forest. Other site characteristics were as follows: the mean area of heronry was $2346m^2$ with range of $500-7,000m^2$, the mean distance between nearest two heronies was 18.1km with range of 5.6-40.4km, the mean distance to nearest village was 297m with range of 10-2,000m, the mean gradient of the topography was $18^{\circ}$ with range of $2^{\circ}{\sim}40^{\circ}$, and 40.0% of heronries were located in the eastern slope.

• Journal of the Korean Solar Energy Society
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• v.31 no.5
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• pp.1-8
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• 2011

In this study, we performed a sensitivity analysis to see how the true north error of a wind direction vane installed to a meteorological mast affects predictions of the annual-average wind speed and the annual energy production. For this study, two meteorological masts were installed with a distance of about 4km on the ridge in complex terrain and the wind speed and direction were measured for one year. Cross predictions of the wind speed and the AEP of a virtual wind turbine for two sites in complex terrain were performed by changing the wind direction from $-45^{\circ}$ to $45^{\circ}$with an interval of $5^{\circ}$. A commercial wind resource prediction program, WindPRO, was used for the study. It was found that the prediction errors in the AEP caused by the wind direction errors occurred up to more than 20% depending on the orography and the main wind direction at that site.

• Journal of Korean Society of Disaster and Security
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• v.13 no.3
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• pp.45-58
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• 2020

Due to a high portion of mountainous terrains in Korea, debris flow and its disasters have been increased. In addition, recently localized flash-floods caused by climate change should add frequencies and potential risks. Grasping and understanding the behaviors of debris flow would allow us to prevent the consequent disasters caused by its occurrence. In this study, we developed a number of cases by changing the bottom slopes and their curvatures and investigated their effects on potential damage caused by the debris flow using FLO-2D. As simulating each bed slopes we analyzed for velocity, depth, impact, reach distance, and reach shape. As a result the lower the average slope, the greater the influence of its curvature and the numerical results were analyzed with showed a well-marked difference in impact stress and flow velocity. The result from this study could be referred for protecting from the debris flows when design countermeasure structures in mountainous regions.

• Fire Science and Engineering
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• v.23 no.5
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• pp.90-95
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• 2009

The wind is very important factor in forest fire spread. Flame spread has a change through wind pattern change in forest fire. In order to analyze the forest fire flame spread rate, change of flame tilt depending on wind may be considering first. This is be cause the flame spread rate varies by the flame tilt changed due to transfer of heat. Especially, as wind speed grow, flame gets closer to surface, heat transfer ratio increase, virgin fuel bed reaches ignition temperature more rapidly, and flame moves faster. This study deduces, through experiment and physical figure analysis, relations on the change behavior of flame tilt due to wind. The value of flame tilt angle calculated from the equation and the experiment value showed average error angle of $3.3^{\circ}$, which is relatively smaller than results of previous studies that used other coefficient. Froude number coefficient A can be calculated in the method provided in this research for estimation of flame tilt angle of virgin fuel bed with varying thermal properties. The research finding is expected to be applied to future studies on flame spread through numerical analysis of heat transfer.

• Fire Science and Engineering
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• v.21 no.4
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• pp.44-51
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• 2007

Most of the Korea temples of cultural property are wooden buildings and easy combusted. They are often located in mountain area far away from the city. It is very difficult to approach the fight area. The putting out is very difficult in the initial fire time. And for protecting the cultural property in the long-term continuous fire source there are some restrictions in water source and suppression system. In this paper the initial putting out fire due to the forest fire and the protection of cultural property in the long-term continuous fire source were researched. The improved project about fire control facilities of the Korea cultural property was proposed. In the proposed project the facilities using Water mist which can reduce more loss than existing facilities using water are applied. In view of the topographic position the method of eliminating the energy of combustibles and wall for cutting off the heat in the fire control facilities are also mentioned.

• Fire Science and Engineering
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• v.32 no.1
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• pp.76-80
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• 2018

The present study investigates the hydrodynamic force acting on the vertical wall of a portable water storage tank which has reentrant bottom topology. To numerically simulate the lapping waves in the tank, functional iterative method for the linearized Peregrine's model which numerically simulates the propagating waves over the slowly-sloped bottom topology is introduced. The numerical experiment condition is controlled to adjust the position and the height of the water supplying nozzle. Finally, it is observed that the maximum wave height at the vertical wall and the ratio of hydrodynamic force to hydrostatic one are amplified accordingly. Therefore it must be give attention to this bad effect of amplified hydrodynamic force by the supply method of fire water in order to have the structural stability of the portable water storage tank when it was used on the reentrant bottom topography.

• Journal of Korea Water Resources Association
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• v.33 no.5
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• pp.611-622
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• 2000

In this study, MODFLOW model is used to analyze the groundwater flow system of Seoguipo area in Cheju island, The final parameters of permeability coefficient and storage coefficient of target area can be obtained by trial and error method using the measured data of pumping rate as initial values. And it is found that the applicability for groundwater flow system is reflected well from the simulation result of the model. Seoguipo area spring water is thought to appear by relatively stable groundwater recharge below EL. 400m according to head distribution through the analysis of observed data considering topographic and geological characteristics, Lee's study(996), and the simulation result. Also it is known that point II, III, and VI show relatively large velocity vectors, and groundwater flows through the movement path which is distributed in various directions of I, II, III, IV, V, VI, and VIl form the result of velocity vector analysis using head distribution result values to analyze the groundwater flow path under unsteady flow condition.dition.