• International Journal of Naval Architecture and Ocean Engineering
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• v.4 no.4
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• pp.353-361
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• 2012

All current shipyards are using the customized CAD/CAM programs in order to improve the design quality and increase the design efficiency. Even though the data structures for ship design and construction are almost completed, the implementation related to the ship design processes are still in progress so that it has been the main causes of the bottleneck and delay during the middle of design process. In this study, we thought that the hole-plan system would be a good example which is remained to be improved. The people of outfitting division who don't have direct authority to edit the structural panels, should request the hull design division to install the holes for the outfitting equipment. For acceptance, they should calculate the hole position, determine the hole type, and find the intersected contour of panel. After consideration of the hull people, the requested holes are manually installed on the hull structure. As the above, many processes are needed such as communication and discussion between the divisions, drawings for hole-plan, and the consideration for the structural or production compatibility. However this iterative process takes a lot of working time and requires mental pressure to the related people and cross-division conflict. This paper will handle the hole-plan system in detail to automate the series of process and minimize the human efforts and time-consumption.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.11
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• pp.148-154
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• 2001

Drilling is one of the most important operations in machining industry and usually the most efficient and economical method of cutting a hole in metal. From automobile parts to aircraft components, almost every manufactured product requires that holes are to be drilled for the purpose of assembly, creation of fluid passages, and so on. It is therefore desirable to monitor drill wear and hole quality changes during the hole drilling process. One important aspect in controlling the drilling process is monitoring drill wear status. A drill-wear monitoring system provides information about drill status. With the information, optimum planning for tool change is possible. And drill-wear monitoring system in needed to evaluated drilled hole quality and the wear of drill. Accordingly, this paper deals with an on-line drill wear monitoring system of the detection of tool wear with the computer vision and the area of the drill flank wear is analyzed quantitatively by the system.

• Korean Journal of Environmental Agriculture
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• v.31 no.3
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• pp.229-234
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• 2012

BACKGROUND: The fruit quality and flowering characteristics of Kiwifruit (A. deliciosa cv. Hayward) in the following year is known to be affected by the extent and timing of defoliation of the current year. In korea, the production of kiwi, which is a perennial, straggling deciduous warm-temperate fruit, is often restricted by wind damage due to typhoons resulting to defoliation at the middle season of its growing period. In this paper, we report the effect of the different timing of defoliation and severities at the current season to the kiwifruit quality. METHODS AND RESULTS: Twenty seven-year-old 'Hayward' trees grown under polyethylene film rain-shelter were defoliated in different days from August to September at seven day-intervals. In each day, 0, 25, 50, 75 and 100% of leaves were removed from the trees. Fruits from each treatment were classified into four floating types (L: lying in bottom, S: standing on bottom, F: floating and SF: floating at the surface of water) by submerging them into tap water. Defoliation of kiwifruit trees in August and September caused air holes in locules of inner pericarp. Increased number of air hole in locules of a fruit was observed in floating types F and SF, and most of the air holes were located in stem end. The defoliation of trees in August significantly reduced the ratio of L-floating type fruits, which have the least number of locule air holes. The extent of defoliation also affected the distribution of the four types, the more leaves removed, the less L-floating type fruits harvested. The weight of fruits from trees defoliated in August was lower than that of fruits from September. Soluble solids content decreased as the number of locule air holes increased. Negative correlations were observed between the extent of defoliation and the weight and soluble solids content of fruits. CONCLUSION: Early defoliation effect on kiwifruit locule air hole occurrence and fruit quality were more severe in August than in September. And also if the defoliation severity is over 25%, severe fruit quality reduction expected to happen due to increase of fruit locule air hole in the inner pericarp.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.13 no.3
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• pp.127-131
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• 2003

High quality zincblende ZnTe(100) epilayers have been grown on semi-insulating $CaAs(100\pm2^{\circ})$substrate by hot-wall epitaxy. To grow high quality ZnTe epilayers, the growth temperature dependence of the surface topography, the growth rate, and the crystalline properties were investigated. From the photoluminescence measured at 10 K, the light hole and heavy hole free exciton emissions splitted by thermal tensile strain were observed and their first excited state emissions were also measured. The low temperature doublet of the heavy hole free exciton is because of the energy separation between longitudinal exciton and transverse exciton due to exciton-polariton coupling.

• Journal of Advanced Navigation Technology
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• v.23 no.4
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• pp.322-327
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• 2019

In this paper, we propose first a scheme of grouping spectrum holes that are created in the multiple channels of primary users, and then by using the scheme we enhance quality of service (QoS) of wideband cognitive radio users in cellular cognitive radio networks. In our scheme, spectrum holes created in each primary channel are predicted by Wiener prediction process, and then the predicted spectrum holes happened in the same time are grouped into a group. The wideband cognitive radio users explore the group of spectrum holes to improve their QoS. Simulation results show that their handoff calls dropping rate and initial calls blocking rate are significantly reduced in our scheme, compared to those in the single primary channel.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.05a
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• pp.230-235
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• 2003

In the micro hole punching, the size and shape of burr and burnish zone are very important factors to evaluate quality of micro holes which depend on punch-die clearance, stain rate, workpiece material and etc. To get micro holes with small burr and wide burnish zone for industrial demands, not only the parametric study but also a study on fracture behavior in shear band are necessary. In this study, 100 $\mu\textrm{m}$, 25 $\mu\textrm{m}$ micro holes in diameter were fabricated on brass (Cu63/Zn37) and SUS 316 foils as aspect ratio 1:1, and the characteristics of micro holes was investigated comparing with man holes over several mm by scanning electron microscopic views and section views. Like macro hole, micro hole is also composed of 4 portions, rollover, burnish zone, fracture zone and it shows similar fracture behavior in shear band, but？ by high strain rate (10$^2$∼ 10$^3$s$\^$-1/) unlike macro hole fabrication and increment of relative grain size several different results are shown.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.842-846
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• 1997

Micro-hole drilling (holes less than 0.5 mm in diameter with aspect ratios larger than 10) is gaining increased attention in a wide spectrum of precision production industries. Alternative methods such as EDM, laser drilling, etc. can sometimes replace mechanical micro-hole drilling but are not acceptable in PCB manufacture because they yield inferior hole quality and accuracy. The major difficulties in micro-hold drilling are related to wandering motions during the inlet stage, high aspect ratios, high temperature,etc. However, of all the difficulties, the most undesirable one is the increase of drilling force as the drill penetrates deeper into hold. This is caused mainly by chip related effects. Peck-drilling is thus widely used for deep hole drilling despite the fact that it leads to low productivity. Therefore, in this paper, a method of cutting force regulation is proposed to achieve continuous drilling. A proportional plus derivative (PD) and a sliding modecontrol algorithm will be implemented for controlling the spinle rotational frequeency. Experimental results will show that sliding mode control reduces the nominal cutting force and its variation better than the PD control, resulting in a number of advantages such as an increase in drill life, fast stabilization of the wandering motion, and precise positioning of the hole.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.19-23
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• 1996

Deburring and edge finishing technology as the last process of machining operation is required for manufacturing of advanced procesion components, duburring has treated as a difficult problem on going tothe highefficency, automation in the FMS. Removal of butt with various shapes, dimensions and properties coultn't has a standard and has depended on manual treatment. Especially, deburring for cross hole inside owing to passing through out perpendicular to a main hole is more difficult, the electrolytic method is proper as its solution at practical aspects. Therefore, for the high effciency and automation of intermal deburring in the cross hole, development of electrolytic debutting technology is needed. So, the new process in the burr treatment is supposed. In this study, in the eliminating burr inside cross hole, the principle and machining performances of electrochemical deburring by Cubic-Boron-Nitrade abrasive electroplate wheel are investigated, Design and manufacture of CBN electroplated wheel and analysis of characteristics with electrolytic debutting are achieved. Also deburring efficiency and electrolytic performance for cross hole were examined according to electrolytic current and electrolytic deburring condition corresponding to acquired edge quality was found out.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.10
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• pp.80-86
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• 1999

Since the quality of the coated wires is in various applications dependant on the coating depth, accuracy of hole size of dies used for coating wires must be maintained precisely, in general within one micron. This paper proposes a new vision system which measures automatically the size and shape of small holes having diameters less than 1mm within an error limit of 1 micron. To quickly obtain the focused image, this paper proposes an estimation method of the camera position using only a couple of defocused hole images. It measures the distributions of light intensity around the image boundary and decides the direction and distance of a camera motion. The proposed system measures the size, shape distortion, inclination of the hole against the axis of the dies structure, to decides the acceptability of the dies for use. The proposed algorithm has been implemented using a cheap 640${\times}$480 image system and has shown an average size error of 1micron when measuring the dieses having 0.1mm to 1.0mm diameters. It can be applied to the inspection of the size and position of holes in PCB, too.

• ETRI Journal
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• v.38 no.5
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• pp.996-1007
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• 2016

This paper presents new hole-filling methods for generating multiview images by using depth image based rendering (DIBR). Holes appear in a depth image captured from 3D sensors and in the multiview images rendered by DIBR. The holes are often found around the background regions of the images because the background is prone to occlusions by the foreground objects. Background-oriented priority and gradient-oriented priority are also introduced to find the order of hole-filling after the DIBR process. In addition, to obtain a sample to fill the hole region, we propose the fusing of depth and color information to obtain a weighted sum of two patches for the depth (or rendered depth) images and a new distance measure to find the best-matched patch for the rendered color images. The conventional method produces jagged edges and a blurry phenomenon in the final results, whereas the proposed method can minimize them, which is quite important for high fidelity in stereo imaging. The experimental results show that, by reducing these errors, the proposed methods can significantly improve the hole-filling quality in the multiview images generated.