• Journal of Institute of Control, Robotics and Systems
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• v.19 no.1
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• pp.15-26
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• 2013

This paper proposes a classification method of parallel, vertical parking states and pillars for parking assist system using ultrasonic sensors. Since, in general parking space detection module, the compressed amplitude of ultrasonic data are received, the analysis of them is difficult. To solve these problems, in preprocessing state, symmetric transform and noise removal are performed. In feature extraction process, four features, standard deviation of distance, reconstructed peak, standard deviation of reconstructed signal and sum of width, are proposed. Gaussian fitting model is used to reconstruct saturated peak signal and discriminability of each feature is measured. To find the best combination among these features, multi-class SVM and subset generator are used for more accurate and robust classification. The proposed method shows 92 % classification rate and proves the applicability to parking space detection modules.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1532-1536
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• 2007

A plastic substrate with tiny rectangular pillars less than 100nm is injection molded to study pattern replication in injection molding. The size of the substrate is 50mm ${\times}$ 50mm and 1mm thick. The substrate has 9 patterned areas of which size is 2mm ${\times}$ 2mm respectively. The lengths of the pillars are 50nm, 100nm, 150nm and 200nm and the width and height are 50nm and about 100nm respectively. A pattern master is fabricated by e-beam writing using positive PR(photo resist) and then a nickel stamper replicated from the PR master by nickel electro-plating. Cr is deposited on the PR pattern master before nickel electro-plating as a conducting layer. Using this nickel stamper, several injection molding experiments are done to investigate effects of the injection molding parameters such as mold temperature, injection rate, packing pressure or pattern location on the replication of the patterns under 100nm.

• Tunnel and Underground Space
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• v.22 no.1
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• pp.60-68
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• 2012

Focusing on the load tunnel, this study assessed the behavior of rock pillars with less than 0.5D of the minimized distance between the two horizontal tunnels by using a three dimensional numerical analysis. Based on a parameter affecting the behavior of rock pillars, this study evaluated different safety factors according to pillar width, depth and rock conditions. It turned out that as the pillar width increases, the current curve of safety factors in accordance with depth and rock conditions shows more of the nonlinear behavior. Judging from the minimum safety factor, the study suggested a design chart, working on the minimized distance between the two horizontal tunnels.

• Journal of the Korean Wood Science and Technology
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• v.33 no.3 s.131
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• pp.11-21
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• 2005

The purpose of this study was to identify the species of the woods used in the main building (Daewoongjeon) of Bulgapsa temple in YeongGwang. Eighty eight woods sampled were divided into four parts; pillars(21), rafters(19), purlins(16) and other wood elements(12). Four species were identified; Pinus spp. (hard pines; diploxylon), Abies spp., Quercus spp. and Zelkova serrata Makino. Pillars and corner-angle rafters were mainly Zelkova; however, other wood elements were mostly Pinus spp. The high ratio of Zelkova in this building would be ascribed to the preference of this species to pines owing to its superior quality before the late Chosun Dynasty.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.2
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• pp.171-178
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• 2014

In this study, the apparent contact angle on the hydrophilic/hydrophobic surfaces with micropillars was studied. The previous researches showed that the Wenzel equation and the Cassie-Baxter equation were thermodynamically derived for the rough hydrophilic/hydrophobic surfaces and generally referenced on the field of wetting phenomena. For the verification of both equations, the apparent contact angle on the hydrophilic/hydrophobic surfaces with micro-pillars was measured. In the comparison between the measured and estimated apparent contact angles with the equations, the differences between the apparent contact angles were analyzed. Conclusively, the available range and limitation of theoretical equations were investigated and further researches about the apparent contact angle on the rough surfaces were proposed.

• Geomechanics and Engineering
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• v.20 no.5
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• pp.447-459
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• 2020

Based on the literature statistical method, the paper publication status of the isolated working face and the distribution of the rockburst coal mine were obtained. The numerical simulation method is used to study the stress distribution law of working face under different mining range. In addition, based on the similar material simulation test, the overlying strata failure modes and the deformation characteristics of coal pillars during the mining process of the isolated working face with thick-hard key strata are analyzed. The research shows that, under the influence of the key strata, the overlying strata formation above the isolated working face is a long arm T-type spatial structure. With the mining of the isolated working face, a series of damages occur in the coal pillars, causing the key strata to break and inducing the rockburst occurs. Combined with the mechanism of rockburst induced by the dynamic and static combined load, the source of dynamic and static load on the isolated working face is analyzed, and the rockburst monitoring methods and the prevention and control measures are proposed. Through the above research, the occurrence probability of rockburst can be effectively reduced, which is of great significance for the safe mining of deep coal mines.

• Journal of the Semiconductor & Display Technology
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• v.11 no.4
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• pp.43-48
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• 2012

The screen printing method is much used in the flat panel display field including the LCD, PDP, FED, organic EL, and etc. for forming the high precision micro-pattern. Also A number of studies of screen printing method has been conducted as the method for the cost down through the improvement of productivity. Because of being the dot printing method of the cylindrical shape not being the line printing method like the existing PDP barrier rib and phosphor, the pillar arrays using the screen printing method is deposited in the hemispherical type not being cylindrical shape in the existing printing process conditions. In this paper, the parameters were set on the screen printing device in order to deposit the cross-sectional shape with the cone or trapezoid shape of the pillar in depositing the pillars used the screen printing device for vacuum glazing. The cross-sectional shape slope of the pillar according to the parameters was measured. And analysis the effect of the screen printing process conditions on the cross-sectional shape slope of pillars based upon the result of being measured. The processing conditions were drawn to minimize the cross-sectional shape slope of pillar.

• Proceedings of the Korean Magnestics Society Conference
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• 2011.12a
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• pp.29-30
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• 2011

We have demonstrated the fabrication of sub 30 nm MTJ pillars with PMA characteristics. The multi-step IBE process performed at $45^{\circ}$ and $30^{\circ}$, using NER resulted in almost vertical side profiles. There deposition on the sidewalls of the NER prevented lateral etching of the resist hard mask allowing vertical MTJ side profile formation without any reduction in the lithographically defined resist lateral dimensions. For the 28nm STT-MTJ pillars, the measured TMR ratio was 13 % with resistance of 1 $k{\Omega}$, which was due to remaining redeposition layers less than 0.1 nm thick. With further optimization in multi-step IBE conditions, it will be possible to fabricate fully operating sub 30 nm perpendicular STT-MTJ structures for application to future non-volatile memories.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.3
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• pp.173-176
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• 2020

This study focuses on a pillar in which is implanted a P-type maneuver under a P base. This structure is called a super junction structure. By inserting the pillar, the electric field concentrated on the P base is shared by the pillar, so the columns can be dispersed while maintaining a high breakdown voltage. Ten pillars were generated during the multi epitaxial process. The interval between pillars is varied to optimize the electric field to be concentrated on the pillar at a threshold voltage of 6 V, a yield voltage of 4,500 V, and an on-state voltage drop of 3.8 V. The density of the filler gradually decreased when the interval was extended by implanting a filler with the same density. The results confirmed that the size of the depletion layer between the filler and the N-epitaxy layer was reduced, and the current flowing along the N-epitaxy layer was increased. As the interval between the fillers decreased, the cost of the epitaxial process also decreased. However, it is possible to confirm the trade-off relationship that deteriorated the electrical characteristics and efficiency.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.492-497
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• 2005

In this study, we propose an advanced nanoindentaion test, Nano Pillar Compression Test (NPCT) to measure a stress-strain relation for micro scale polymer structures. Firstly, FEM analysis is performed to research behavior of micro polymer pillars in several specimen aspect ratios and different friction conditions between specimen and tip. Based on the FEM results, micro scale UV-curable polymer pillars are fabricated on a substrate by Nano Stereo Lithography (NSL). To measure their mechanical properties, uniaxial compression test is performed using nanoindentation apparatus with flat-ended diamond tip. In addition, the dependency of compression properties on loading condition and specimen size are discussed.