• Transactions of Materials Processing
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• v.27 no.6
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• pp.347-355
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• 2018

This study investigated the effects of the processing number of multi-axial diagonal forging (MADF) on the microstructural changes of OFC fabricated by MADF processes. The as-extruded OFC was cut to $25mm^3$ cube for the MADF processes. The MADF process consists of plane forging with a thickness reduction of 30% and diagonal forging with a diagonal forging angle of $135^{\circ}$. In order to analyze the microstructural evolutions according to the number of repetitions, 1, 2, 3 and 4 cycles of the MADF process were performed. OFC specimens were successfully deformed without surface cracking for up to 4 cycles of MADF. The grain size, average misorientation and average grain orientation spread (GOS) of MADF processed materials were analyzed using EBSD technique and their Vicker's hardness were also measured. The results showed that MADF process effectively refined the microstructure of OFC with initial average grain size of $84.2{\mu}m$. The average grain sizes of specimens MADF processed for 1, 2, 3, 4 cycles were refined to be $8.5{\mu}m$, $2.2{\mu}m$, $1.5{\mu}m$, $1.1{\mu}m$, respectively. The grain refinement seemed to be saturated when OFC was MADF processed over 2 cycles. In the case of specimens subjected to two or more cycles of MADF, the degree of decrease in average grain size was drastically reduced as the number of cycles increased due to softening phenomena such as dynamic recovery or dynamic recrystallization during processing. The degree of increase in average Vicker's hardness was also dramatically reduced as the number of cycles increased due to the same reason.

• Journal of Korea Game Society
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• v.6 no.2
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• pp.3-12
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• 2006

Recently, Many 3D augmented reality games that provide strengthened immersive have appeared in the 3D game environment. In this article, we describe a barehanded interaction method based on human hand gestures for augmented reality games. First, feature points are extracted from input video streams. Point features are tracked and motion of moving objects are computed. The shape of the motion trajectories are used to determine whether the motion is intended gestures. A long smooth trajectory toward one of virtual objects or menus is classified as an intended gesture and the corresponding action is invoked. To prove the validity of the proposed method, we implemented two simple augmented reality applications: a gesture-based music player and a virtual basketball game. In the music player, several menu icons are displayed on the top of the screen and an user can activate a menu by hand gestures. In the virtual basketball game, a virtual ball is bouncing in a virtual cube space and the real video stream is shown in the background. An user can hit the virtual ball with his hand gestures. From the experiments for three untrained users, it is shown that the accuracy of menu activation according to the intended gestures is 94% for normal speed gestures and 84% for fast and abrupt gestures.

• Journal of Korea Multimedia Society
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• v.12 no.10
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• pp.1363-1373
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• 2009

In a ubiquitous computing environment, people more and more become to use multiple displays. When using such ubiquitous displays, it is needed for users to seamlessly interact with the displays for a certain content. In this paper, we propose a seamless interface that allows users to see photos across multiple displays. Many photos can be displayed on a screen at the same time because they are shown in 3D space. And a group of photos is represented using a cube metaphor. A user can manipulate photos directly using a touch screen and also see the photos continuously using PDAs when the user moves to other places. In addition, the user can interact with the photos seamlessly using another display. The developed system was designed to interact according to user's movements and not to draw user's attention too much as a kind of ambient display. Using RFID and ultrasonic sensors it recognizes a user and the user's proximity to the display, and then automatically determines the screen image and the user interface accordingly.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.2
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• pp.186-200
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• 2010

In order to render global illumination realistically, we need to accurately compute the direct and indirect illumination that represents the light information incoming through complex light paths. In this process, the indirect illumination at given point is greatly affected by surrounding geometries. Harmonic mean distance is a mathematical tool which is often used as a metric indicating the distance from a surface point to its visible objects in 3D space, and plays a key role in such advanced global illumination algorithms as irradiance/radiance caching and ambient occlusion. In this paper, we analyze the accuracy of harmonic mean distance estimated against various environments in the final gathering and photon mapping methods. Based on the experimental results, we discuss our experiences and future directions that may help develop an effective harmonic mean distance computation method in the future.

• Transactions of Materials Processing
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• v.27 no.4
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• pp.250-256
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• 2018

Oxygen-free copper (OFC) was prepared as a 90 mm cube and then processed with Multi-Axial Diagonal Forging - Initialization of Prior manufacturing History (MADF). The MADF process has been newly developed as a severe plastic deformation method. The MADF process consists of upset forging with a thickness reduction of 30% and diagonal forging with a diagonal angle of $135^{\circ}$. 1 cycle process consists of a 12 passes forging process. In order to analyze the characteristic changes according to the number of iterations, 1, 2, and 3 cycles of the MADF process were performed. The OFC specimens were MADF processed without surface cracks up to 3 cycles. The microstructure, hardness and tensile test of processed materials were analyzed to study the change of material properties according to the amount of MADF process. The results showed that the MADF process effectively refined the microstructure and increased the strength of OFC. In the case of specimens processed for more than 2 cycles, the grains of all measurement regions were refined to be less than $7{\mu}m$ of grain size. The 1 cycle MADF processed OFC showed the highest mechanical properties with the hardness of 132 HV and tensile strength of 395 MPa. Hardness and strength seemed to be saturated when processed over 2 cycles.

• Journal of Korea Multimedia Society
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• v.20 no.8
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• pp.1447-1455
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• 2017

In a trawl-net simulation, it is very important to process the physical phenomenons resulting from real collisions between a net and fishes. However, because it is very difficult to reconstruct the surface with mass points, many researchers have generally detect the collision using an approximation model employing a sphere, a cube or a cylinder. These approaches occur often result in inaccurate movements of a fish due to the difference between a real-net and a designed-net. So, many systems have manually adjusted a net surface based on actual measurements of mass points. These methods are very inefficient because it needs much times in an adjustment and also causes more incorrect inputs according to a rapid increment in the number of points. Therefore, in this paper, we propose a reconstruction method that it semi-automatically reconstructed trawl-net surfaces using the equation of motion at each mass point in a mass-spring model. To get an easy start in a beginning step of the spread, it enables users to get interactive adjustment on each mass point. We had designed a trawl-net model using geometrical structures of trawl-net and then automatically reconstructed the trawl-net surface using scale-space meshing techniques. Last, we improve the accuracy of reconstructed result by correction user interaction.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.23 no.2
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• pp.113-117
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• 1978

An attempt was made to establish a mass-screening technique for resistance to purple seed stain .disease in soybean. Seeds sterilized in 1 : 10000 'mercuric chloride for 1 minute and transffered to Petridishes containing 20ml water agar plus 50ppm of the sodium salt of 2,4-D were inoculated by placing a small agar cube containing fungal mycelium on the seed coat of each seed. A positive correlation between natural infection of purple seed :stain and purple discoloration by seed inoculation technique was highly significant and by this technique, some native soybean collections and introduced varieties were tested for resistance to the disease. Most of the soybean varieties tested were susceptible except for the varieties Hill, Harosoy and Sac, resistant comparatively.

• Macromolecular Research
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• v.15 no.5
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• pp.412-417
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• 2007

In the present study, crosslinked poly(vinyl alcohol) (PVA) membranes were prepared at different temperatures using poly(styrene sulfonic acid-co-maleic acid) (PSSA_MA) (PVA:PSSA_MA = 1:9). The hybrid mem-branes were prepared by varying the TEOS content between 5 and 30 wt%. The PSSA_MA was used both as a crosslinking agent and the hydrophilic group donor ($-SO_3H$ and/or-COOH). The proton conductivity increased with up to 20 wt% TEOS, but decreased above this level, although the water content decreased with increasing TEOS content. This result suggests that the silica doped into the membrane improved the formation of proton-conduction pathways due to the absorption of molecular water. The PVA/PSSA_MA/Silica containing TEOS 20% showed both high proton conductivity (0.026 S/cm at $90^{\circ}C$) and low methanol permeability ($5.55{\times}10^{-7}cm^2/s$).

• Journal of Animal Science and Technology
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• v.47 no.1
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• pp.39-48
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• 2005

Outside muscle of pork ham were cut to cube(7 $\times$ 10 $\times$2 ern) and three Korea traditional seasonings such as soybean paste(Tl), garlic paste(T2), red pepper paste(T3) were seasoned by the proportions of meat to seasonings(1 : 1), respectively. The seasoned samples were fermented by fill into plastic box at 0 $\pm$ 1 $^{\circ}C$ for 10 days. And then, the fermented meat from each pack was vacuum-packaged and stored at 0 $\pm$ 1 $^{\circ}C$ for up to 9 weeks. pH and shear force were decreased during storage periods in all treatment groups and WHC was decreased with storage in T2. The saccarinity of T1 was increased and salinity increased during storage in all treatment groups. pH of T2 was increased than that of other treatments, while decreased saccarinity and shear force of in T2. The salinity were higher in the order of T1 > T2 > T3. Volatile basic nitrogen (VBN) value were increased with storage in all treatment groups. Thiobarbituric acid reactive substances (TSARS) value of Tl was increased with storage while it was decreased T2. Thiobarbituric acid reactive substances(TSARS) value was higher in the order of T1 > T3 > T2 at 9weeks of storage. Surface meat L' values of T1 was increased with storage and T3 decreased with storage whereas, surface meat a' values of T1 was decreased with storage, and T2 was increased with storage. Surface meat b' values of T3 was decreased with storage. Escherichia coli were decreased during storage periods in all treatment groups.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.6
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• pp.82-92
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• 2022

This study aims to investigate the effect of total electrochemical cell resistance (TECR) on electrochemical impedance (EI) measurements of reinforced concrete (RC) by electrochemical impedance spectroscopy (EIS) using a three-electrode system. A series of experimental study is performed to measure electrochemical behavior of a steel bar embedded in a concrete cube specimen, with a side length of 200 mm, in various experimental conditions. Main variables include concrete dry conditions, coupling resistance between sensing electrodes and concrete surface, and area of the counter electrode. It is demonstrated that EI values remains stable when the compliant voltage of a measuring device is sufficiently great compared to the potential drop caused by TECR of concrete specimens. It is confirmed that the effect of the coupling resistance of TECR is far more influential than other two factors (concrete dry conditions and area of the counter electrode). The results in this study can be used as a fundamental basis for development of a surface-mount sensor for corrosion monitoring of reinforced concrete structures exposed to wet-and-dry cycles under marine environment.