• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.30 no.6_2
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• pp.631-642
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• 2012

This study aims to predict inundation and flood-stricken areas more accurately by simulating flood damage caused by reversible flow of rain water in the upper water system through precise 3D terrain model and backwater output. For the upstream of the South Han-River, precise 3D terrain model was established by using aerial LiDAR data and backwater by area was output by applying the storm events of 2002 including the history of flood damage. The 3D flood simulation was also performed by using GIS Tool and for occurrence of related rainfall events, inundation events of the upriver region of water system was analyzed. In addition, the results of flood simulation using backwater were verified by making the inundation damage map for the relevant area and comparing it with flood simulation's results. When comparing with the results of the flood simulation applying uniformly the gauging station's water surface elevation used for the existing flood simulation, it is found that the results of the flood simulation using backwater are close to the actual inundation damage status. Accordingly, the causes of flood occurred in downstream of water system and upstream that has different topographic characteristics could be investigated and applying the simulation with backwater is proved more proper in order to procure accuracy of the flood simulation for the upriver region.

• International Journal of Highway Engineering
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• v.18 no.2
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• pp.91-101
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• 2016

PURPOSES : The aim of this study was to compare the performance of the QUEENSOD method and the gravity model in estimating Origin-Destination (O/D) tables for a large-sized microscopic traffic simulation network. METHODS : In this study, an expressway network was simulated using the microscopic traffic simulation model, VISSIM. The gravity model and QUEENSOD method were used to estimate the O/D pairs between internal and between external zones. RESULTS: After obtaining estimations of the O/D table by using both the gravity model and the QUEENSOD method, the value of the root mean square error (RMSE) for O/D pairs between internal zones were compared. For the gravity model and the QUEENSOD method, the RMSE obtained were 386.0 and 241.2, respectively. The O/D tables estimated using both methods were then entered into the VISSIM networks and calibrated with measured travel time. The resulting estimated travel times were then compared. For the gravity model and the QUEENSOD method, the estimated travel times showed 1.16% and 0.45% deviation from the surveyed travel time, respectively. CONCLUSIONS : In building a large-sized microscopic traffic simulation network, an O/D matrix is essential in order to produce reliable analysis results. When link counts from diverse ITS facilities are available, the QUEENSOD method outperforms the gravity model.

• Nuclear Engineering and Technology
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• v.52 no.6
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• pp.1164-1171
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• 2020

T-junction structures play an important role in nuclear power plant systems. Research on liquid entrainment is mostly based on small-scale branch pipes (d/D ≤ 0.2) and attention paid to large-scale branch pipes (0.33 < d/D < 1) is insufficient. Accordingly, this study implements a series of experiments on the liquid entrainment of T-junction with different angles (32.2°,47.9°,62.3°,90°) through a large-scale branch (d/D = 0.675). The onset liquid entrainment is related to the gas phase Froude number Fr_g, the dimensionless gas chamber height h_b/d and the branch pipe angle 𝜃. As Fr_g increases, h_b/d also rises. With a constant h_b/d, the onset liquid entrainment changes from droplets entrainment by the gas phase to that by the rising liquid film. The steady-state liquid entrainment is related to w_3g, h/d and 𝜃. With constant w_3g and h/d, the branch quality grows as the branch angle increases. With a certain h/d, the branch quality increases, as the w_3g number increases.

• Journal of Korea Multimedia Society
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• v.10 no.4
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• pp.527-536
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• 2007

This paper proposes a 3D fashion design system that generates a 3D clothes model by using 2D patterns of clothes and drapes the 3D clothes model on a 3D human model. In the proposed system, 2D patterns of clothes are designed by selecting comer points of 2D mesh. After designing 2D patterns, a 3D clothes model is designed by describing the control points to be connected between 2D patterns. The proposed system reads a 3D human body model file and the designed 3D clothes model and creates a 3D human model putting on the clothes by using the mass-spring model based physical simulation. It calculates collision and reaction between the triangles of human body model and those of clothes for realistic simulation. Because the number of triangles is very large, the collision and reaction processing need a lot of time. To solve this problem, the proposed system decreases the number of collision and reaction processing by using the Octree space subdivision technique. It took a few seconds for generating a 3D human model putting on the designed 3D clothes.

• Fashion & Textile Research Journal
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• v.12 no.5
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• pp.582-590
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• 2010

Garment design needs an iterative manipulation of 2D patterns to generate a final sloper. Traditionally there have been two kinds of design methodologies such as the flat pattern method and the pattern draping method. But today, it is possible to combine the advantages from the two methods due to the realistic cloth simulation techniques. We devised a new garment design system which starts from 3D initial drape simulation result and then modifies the garment by editing the 2D flat patterns synchronously. With this interactive methodology using real-time pattern deformation technique, the designer can freely change a pattern shape by watching its 3D outlook in real-time. Also the final garment data were given relative coordinates with respect to the human anthropometric feature points detected by an automatic body feature detection algorithm. Using the relative human body coordinate system, the final garments can be re-used to an arbitrary body data without repositioning in the drape simulation. A female shirt was used for an example and a 3D body scan data was used for an illustration of the feature point detection algorithm.

• Journal of Advanced Navigation Technology
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• v.27 no.4
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• pp.488-494
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• 2023

In this paper, scenario-based urban flood prediction for the entire Jinju city was performed, and a simulation domain was constructed using G2D as a 2-dimensional urban flood analysis model. The domain configuration is DEM, and the land cover map is used to set the roughness coefficient for each grid. The input data of the model are water level, water depth and flow rate. In the simulation of the built G2D model, virtual rainfall (3 mm/10 min rainfall given to all grids for 5 hours) and virtual flow were applied. And, a GPU acceleration technique was applied to determine whether to run the flood analysis model in the target area. As a result of the simulation, it was confirmed that the high-resolution flood analysis time was significantly shortened and the flood depth for visual flood judgment could be created for each simulation time.

• Journal of the Korea Society for Simulation
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• v.8 no.2
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• pp.13-28
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• 1999

The main purpose of this paper is to design and implement forest fire information system (FOFIS) for effective prevention of forest fire using GIS, database, 3-D graphics, and simulation techniques. In contrast to conventional fire information systems that are mostly based on the 2-D graphics and analytic modeling approaches, we have proposed the cell-based modeling approaches, i.e., spatial, data, and simulation modeling approaches. The cell-based spatial modeling is proposed by eliminating the cliff effect of the typical elevation model so that it can provide realistic 3-D graphics of the forest fire. The cell-based data modeling of geography, meteorology, and forestry information is also proposed. The cell-based dynamic modeling for forecasting of the fire diffusion is developed using the variable structure modeling techniques. Several simulation tests of FOFIS performed on a sample forest area of Chungdo, Kyungsangbukdo will demonstrate our approaches.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.1
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• pp.86-93
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• 2015

Recently, the development of Maritime Service Portfolios (MSPs) for the safe navigation of ship has been discussed internationally. For the successful service of the MSPs, first of all, studies for the standardization about the structure and data structure of MSPs should be preceded. Also, it is necessary to evaluate and assess whether the services are effective for safe navigation, and provided data and portrayal methods are proper. However, because great dangers will be accompanied when untested MSPs about their effectiveness and safety are applied in real ship navigation, it is necessary that effectiveness and safety of the MSPs should be proven under various navigational conditions and environments by simulation. In this paper, we propose a 3D navigation simulation system using desktop PC environment, which is proper for evaluating the effectiveness of MSPs. The system consists of three modules which are simulation scenario editor, 3D visualization of navigational environment and 2D navigational equipment. The scenario editor module provides an environment setting for simulation, such as properties, routes and positions of vessels and aids to navigations. It also provides functions to create a scenario for the simulation to operate. Additionally, the 3D visualization module provides 3D navigational environment which shows interplay between geographical and navigational environment based on the created scenario. The 2D navigational equipment module provides visualization functions of various navigational equipment, shows the interaction between ship's navigational equipment and ship's environment. The simulation scenario, in which various kinds of ships are routing in the port, is created by the developed simulation system, and experimented whether this developed system is appropriate to evaluate and assess the MSPs developed by the International Maritime Organization.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.6
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• pp.997-1002
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• 2017

Underwater communication, which is used acoustic channel of 1500[m/s] speed being different of wireless electric wave in terrestrial communication, is sensitive on water temperature and salinity and also affected from 3D underwater space. 3D underwater communication is sensitive on propagation loss of acoustic wave and underwater noise with complexity of communication space. In this paper, transmission performance with consideration of these characteristics of 3D underwater communication environments is measured and analyzed on MANET operated on 3D underwater communication environments. Some underwater MANET operation conditions will be suggested. Computer simulation with underwater simulator based on NS-2 will be used for performance measure, performance parameter like as throughput, transmission delay, packet loss rate and consumed energy will be used in simulation for performance measure.

• Fashion & Textile Research Journal
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• v.15 no.6
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• pp.963-970
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• 2013

The purpose of this study was to develop torso pattern of underweight female in their 20s~30s by using Clo 3D virtual garment simulation system. The results were as follows; first, as a result of analyzing torso somatotype, underweight women showed lower average than average values of whole women in their twenties and thirties in the items such as length, width, circumference, thickness except for height. Second, by using 3D virtual garment simulation, new torso pattern considered underweight female was development. The basic numerical formula were as follows ; bust girth B/2+3.5, armhole depth B/4+0.5, front waist girth W/4+0.5+0.7, back waist girth W/4+0.5-0.7, front hip girth H/4+1+0.5, back hip girth H/4+1-0.5, chest width B/6+3.1, back width B/6+4.5, neck width B/12+0.2 and neck depth B/12+1.7. Third, by reducing hollowed amount of front, back, and side line, and hollowed amount of back center line, the reduced quantity was included to darts amount. Number of dart was adjusted to two pieces so that darts amount was equally distributed to two darts. Forth, according to the results of the new torso pattern's appearance evaluation, it estimated more highly than existing pattern in silhouette and ease amount, confirming that new torso pattern was appropriate for the underweight women. This study is expected to serve as one of important basic data for ensuing studies that may utilize 3D virtual garment simulation system with 2D patterns, and also for future 3D pattern production program development.