• Transactions of the Korean Society of Automotive Engineers
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• v.3 no.2
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• pp.136-145
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• 1995

The aim of this study is to gain a better understanding of the effect of a flow motion on the flame development by means of an optically-accessible constant-volume combustion chamber and the visualization technique of a combustion flame. At first, the characteristics of a flame propagation are investigated in the combustion field of the two kinds of flow conditions such as a quiescent and a flowing condition, and methane-air mixture is used as fuel. Then the same investigation is performed in two flow configurations : bulk flow motion type and turbulence generating type. In this study, the combustion phenomena are analyzed by measuring the combustion pressure, flame propagation speed, mean velocity, turbulent intensity, and mass fraction burned.

• Journal of the Korea Computer Graphics Society
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• v.20 no.4
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• pp.1-7
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• 2014

The volume rendering has become an important technique in many applications along with hardware development. Understanding and perception of volume visualization benefit from visual cues which are available from shading. Better visual cues can be obtained from global illumination models but it's huge amount of computation and extra GPU memory need cause a lack of interactivity. In this paper, in order to improve visual cues on volume rendering, we propose an image space occlusion shading model which requires no additional resources.

• Journal of the Korean Society of Visualization
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• v.8 no.3
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• pp.41-48
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• 2010

A visualization study to evaluate bubble motion in a tab water filled cylindrical tank with a varying flow rate of compressed air is conducted. The flow rate of compressed air varies from 1 to 5 L/min. Time resolved images are acquired by a high speed camera in 10 bit gray level at 100 fps and the measurement volume is irradiated by a 230 W halogen lamp. It is observed that there are three different regions; the bubble formation region, the rising bubble region and the free surface region. During the rise of bubble, the shape is changed as if an elastic body. Based on the binarized bubble image, the mean diameters of rising bubbles are estimated at beneath of the free surface. As the gas flow rate increases, the mean diameter is increased and the rising velocity also increases with buoyancy force.

• The KIPS Transactions:PartA
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• v.10A no.1
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• pp.59-68
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• 2003

3-D data modeling of a volumetric scattered data is highly demanded for geological structure inspection, environment visualization and supersonic testing. The data used in these area are generally irregularly scattered in a volume data space, which are much different from the structured points data (cuberille data) used in Marching cube algorithm. In this paper, first we explore a volume modeling method for the scattered data based on tetrahedral domain. Next we propose a method for solving the ambiguity of tetrahedral domain decision using asymptotic decider criterion. Last we implement a simple visualization system based on the proposed asymptotic decider criterion and compare it with a system based on sphere criterion. In deciding tetrahedral domain, sphere criterion considers only positional values but asymptotic decider criterion considers not only positional values but also functional values, so asymptotic decider criterion is more accurate on deciding tetrahedral domain than sphere criterion.

• Spatial Information Research
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• v.23 no.6
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• pp.109-116
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• 2015

In this study, define the concept of spatial big data and special feature of spatial big data, examine information visualization methodology for increase the insight into the data. Also presented problems and solutions in the visualization process. Spatial big data is defined as a result of quantitative expansion from spatial information and qualitative expansion from big data. Characteristics of spatial big data id defined as 6V (Volume, Variety, Velocity, Value, Veracity, Visualization), As the utilization and service aspects of spatial big data at issue, visualization of spatial big data has received attention for provide insight into the spatial big data to improve the data value. Methods of information visualization is organized in a variety of ways through Matthias, Ben, information design textbook, etc, but visualization of the spatial big data will go through the process of organizing data in the target because of the vast amounts of raw data, need to extract information from data for want delivered to user. The extracted information is used efficient visual representation of the characteristic, The large amounts of data representing visually can not provide accurate information to user, need to data reduction methods such as filtering, sampling, data binning, clustering.

• Journal of the Korean Society of Visualization
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• v.9 no.4
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• pp.74-79
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• 2011

In this study the change of free surface vortex is represented at different times according to height of water and with or without curtain wall installation. The air volume fraction is investigated at each condition of water level and the influence about creation of vortex is analyzed. The height of sump intake is taken as 100mm and the water level is divided into 5 steps. The sump model is the TSJ model and the curtain wall is applied by HI standard of America. The results shows that the free surface vortex can be identified on the isotropic surface at air volume fraction 1%~5% and the vortices make an air column from the free surface to the sump intake and are created and destroyed repeatedly. In the higher water level, less air is absorbed into the intake pipe. After curtain wall installation, the suction rate of the air volume fraction is decreased by 6.7%. The result of the vortex motion according to time, works on a cycle.

• The KIPS Transactions:PartA
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• v.13A no.7 s.104
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• pp.639-646
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• 2006

Data compression technologies enable us to store and transfer large amount of data efficiently, and become more and more important due to increasing data size and the network traffic. Moreover, as a result of the increase of computing power, volumetric data produced from various applied science and engineering fields has been getting much larger. In this Paper, we present a volume compression scheme which exploits Daubeches wavelet transform. The proposed scheme basically supports lossy compression for 3D volume data, and provides unit-wise random accessibility. Since our scheme shows far lower error rates than the previous compression methods based on Haar filter, it could be used well for interactive visualization applications as well as large volume data compression requiring image fidelity.

• Journal of the Korean Society of Visualization
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• v.14 no.3
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• pp.22-27
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• 2016

A sweeping jet actuator (SJA) is an instrument generating pulsing jets with no moving elements. Because of its simple design and high durability to shock and vibration, SJA has recently drawn increasing attention for the application to flow control such as aerodynamic control of a wing and thrust vectoring of a jet engine. However, experimental and numerical studies on SJA have been limited to internal flow structure of SJA. In this study, we investigated the flow structure and its variation in the outlet of SJA. We carried out the experiment to understand the flow structures using PIV (Particle Image Velocimetry). The flow structure varies with a degree of the outlet and volume flow rate. There is leaking process during half jetting cycle. The process of the main jet can occur because the jet moving time increased from one side to the other side.

• Proceedings of the Korea Society for Simulation Conference
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• 2001.10a
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• pp.237-247
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• 2001

In this paper we present an overview of existing state of the art visualization techniques fur the interactive analysis of results from numerical simulations and measurements. We describe the basic concepts and key ideas behind these different visualization methods in this paper. The potential of these techniques for an efficient integration into a virtual reality environment will be investigated. Furthermore we present our first demonstrator fur visualizing multiparametric data and give an outlook on our plans for further exploiting and developing these techniques in an upcoming project.

• Journal of the Korean Society of Visualization
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• v.20 no.2
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• pp.63-69
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• 2022

In this study, we numerically simulate the condensational growth of micron-sized particles traveling through a pipe filled with humidified air. Using the finite volume method and Lagrangian particle tracking technique, the mixture of particle-laden flow with moist air in a T-juction pipe is simulated. The condensational growth of particles is calculated by considering the mass transfer of vapor in the air onto the particle surface. The results indicate that the growth rate of the particles increases as the relative humidity of air is higher. Furthermore, the placement of a porous media with low permeability in the pipe could enhance the degree of condensational growth.