• Journal of the Korea Institute of Information and Communication Engineering
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• v.2 no.4
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• pp.643-652
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• 1998

This paper presents the characteristics of a relay station antenna with the newly designed back-plate structure which is composed of the U-shaped metal plate for suppression of the back lobe by edge diffraction. The back lobe level of the conventional type was about -20 dB in the -z direction ( 180 ) . In order to improve the characteristics, the U-shaped mesh type metal plate is considered, where the design condition of the model antenna satisfies the wide null point angle range with the back lobe level of -30 dB below in the -z direction. The design parameters with the minimum back lobe level such as the dipole length, the distance between dipole elements and the back plate size have been found by using the released NEC Win Pro code. The calculated and measured back lobe Bevel of model antenna have been obtained 48.48 dB and -45 dB at 325 MHz, respectively.

• Journal of the Society of Naval Architects of Korea
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• v.46 no.1
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• pp.24-30
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• 2009

The purpose of this study is to investigate the fatigue strength in accordance with back plate of butt welded specimens. Fatigue life of butt welded specimens was presented for determining the effect of back plates in terms of fatigue strength. As a results, fatigue strength of butt welded specimens with steel back plate show a decrease as compared against the butt welded specimens with ceramic back plate. Compared with the fatigue strength with respect to the existence of steel back plate, the specimens without back plate were much higher than the specimens with back plate.

• Transactions of Materials Processing
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• v.12 no.8
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• pp.724-729
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• 2003

In order to study the shearing characteristic of anti-vibration sheet metal which is used to reduce vibration noise, a blanking die was manufactured to blank a workpiece. The variables employed in this study were clearance, type of stripper plate, position of the rubber layer and type of the die design. These variables were used to study the effects on burr height, blank diameter and camber height. In the case of burr height from experimental investigation, the push-back die, combined with a movable stripper plate, showed greater burr height. The rubber-top position of a workpiece resulted in better qualities regardless of working variables. In the comparison of diameter measurement, the use of the push-back die with a fixed stripper plate, with a 4.5% clearance, showed better accuracy. For comparing camber height, the push-back die resulted in less cambering than the drop-through die. Also, the larger the clearance, the greater was the camber height. Considering experimental results, the shearing of anti-vibrational sheet metal is best achieved when the rubber layer is laying on the top, blanked with a fixed stripper plate in a push-back die, with a 4.5％ clearance.

• Transactions of Materials Processing
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• v.30 no.1
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• pp.35-42
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• 2021

Magnesium alloys are used in electronic devices such as laptops due to their lightweight features as well as vibration absorption and electromagnetic shielding properties. However, the precision of electronics is limited by the large number of small and precise ribs, the cost-effective manufacture of which requires appropriate technology. Plate forging is an efficient manufacturing process that can address these challenges. In this study, plate forging of magnesium alloys was investigated specifically for the fabrication of laptop cover. The plate forging process with back-pressure was used for near-net shape formation. Finite element analysis was used to select appropriate variables for back-pressure formation to generate ribs of various sizes and shapes without defects. The reliability of the analysis was verified to manufacture the prototype. The effect of back-pressure can be verified via fabrication of prototypes as well as structure and forming analysis based on finite element method. The process design factor of back-pressure increases formability without defects of under-filling and flow-through. Moreover, the tensile strength was maintained even after high temperature plate forging at 370 ℃, and the elongation was improved.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.08a
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• pp.29-34
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• 2003

In order to study the shearing characteristics of anti-vibration sheet metal which has been bonded by resin, a blanking die of 40.02mm was manufactured to blank a material and it is used to reduce vibrational noise. The variables employed in this study were 1) Clearance 2) types of stripper plate, and 3) types of the die design technique. These variables were used to study the effects on burr height, diameter of product, and camber height. Lastly, the effect of the position of the rubber during blanking was observed. In the case of burr height from experimental investigation, the push-back die, combined with a movable stripper plate, resulted in the concentration of additional pressure between the cutting edges, meaning the crack initiation was delayed. This result was not affected by lubrication, although appropriate lubrication is preferred to enable a longer lasting die in terms of wear, which results from the presence of adhesive as the sheet metal is blanked. In the comparison of diameter measurement, the push-back die, combined with the back pressure from the knock-out plate showed a favorable precision. The use of the push back die with a fixed stripper plate, with a $4.5\%$ clearance, showed better accuracy in the diameter measurement. For comparing camber height, the push back die resulted in less cambering than the drop-through die. Also, the larger the clearance, the greater was the camber height. Considering experimental results, the shearing of anti-vibrational sheet metal is best achieved when the rubber is laying on the top, blanked with a fixed-stripper plate in a push-back die, with a $4.5\%$ clearance.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.1
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• pp.8-19
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• 2014

In this paper, a robust design of the back-plate of the brake pad to decrease the uneven wear of the pad was studied. A finite element analysis was performed to analyze the pressure distributions on the contact surfaces. Optimized back-plate shape of the brake pad was determined using the Taguchi method. The effectiveness of the robust design was clarified by the wear tests with a dynamometer.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.20 no.4
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• pp.1491-1500
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• 1996

Unstable performance deterioration was found on the performance curve of a small propeller fan with a back plate. To investigate this phenomenon and the effects of the back-plate on the performance of the fan, performance tests and flow measurement using 3-hole pitot tube were carried out. Measurements showed that when the flow rate is small, the radial flow dominates, and when the flow rate is large, the axial flow dominates. Performance characteristic of the propeller fan changes from radial to axial type as the flow rate increases. Unstable performance changes are the result of type change of the flow through the fan.

• Geomechanics and Engineering
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• v.31 no.6
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• pp.599-614
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• 2022

One of the methods of stabilizing retaining walls, embankments, and deep excavations is the implementation of plate anchors (like the Geolock wall anchor systems). Back-to-back Mechanically Stabilized Earth (BBMSE) walls are common stabilized earth structures that can be used for bridge ramps. But so far, the analysis of the interactive behavior of two back-to-back anchored walls (BBAW) by double-plates anchors (constructed closely from each other and subjected to the limited-breadth vertical loading) including interference of their failure and sliding surfaces has not been the subject of comprehensive studies. Indeed, in this compound system, the interaction of sliding wedges of these two back-to-back walls considering the shear failure wedge of the foundation, significantly impresses on the foundation bearing capacity, adjacent walls displacements and deformations, and their stability. In this study, the effect of horizontal distance between two walls (W), breadth of loading plate (B), and position of vertical loading was investigated experimentally. In addition, the comparison of using single and equivalent double-plate anchors was evaluated. The loading plate bearing capacity and displacements, and deformations of BBAW were measured and the results are presented. To evaluate the shape, form, and how the critical failure surfaces of the soil behind the walls and beneath the foundation intersect with one another, the Particle Image Velocimetry (PIV) technique was applied. The experimental tests results showed that in this composite system (two adjacent-loaded BBAW) the effective distance of walls is about W = 2.5*H (H: height of walls) and the foundation effective breadth is about B = H, concerning foundation bearing capacity, walls horizontal displacements and their deformations. For more amounts of W and B, the foundation and walls can be designed and analyzed individually. Besides, in this compound system, the foundation bearing capacity is an exponential function of the System Geometry Variable (SGV) whereas walls displacements are a quadratic function of it. Finally, as an important achievement, doubling the plates of anchors can facilitate using concrete walls, which have limitations in tolerating curvature.

• The Journal of the Korea institute of electronic communication sciences
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• v.5 no.5
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• pp.471-476
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• 2010

In this paper, we propose an effective method that recognizes the vehicle license plate using RGB color information and back-propagation neural network algorithm. First, the image of the vehicle license plate is adjusted by the Mean of Blue values in the vehicle plate and two candidate areas of Red and Green region are classified by calculating the differences of pixel values and the final Green area is searched by back-propagation algorithm. Second, our method detects the area of the vehicle plate using the frequence of the horizontal and the vertical histogram. Finally, each of codes are detected by an edge detection algorithm and are recognized by error back-propagation algorithm. In order to evaluate the performance of our proposed extraction and recognition method, we have run experiments on a new car plates. Experimental results showed that the proposed license plate extraction is better than that of existing HSI information model and the overall recognition was effective.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.7
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• pp.1759-1772
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• 1994

In this study, we re-examined the Tate's modified Bernoulli equation to study penetration phenomena for long rod projectile into single or multi-layered finite thickness plates. We used the force equlibrium equation at mushroomed nose/target interface instead of conventional pressure equation at the stagnation point. In our penetration model, we considered the velocity dependent $R_t$ value for semi-infinite target and considered only the back face effect for finite target. To compensate for $R_t$ value according to target's thickness and back face effect, we used the spherical cavity expansion theory for semi-infinite plate and used the cylindrical cavity expansion theory for finite plate. Also we developed the experimental technique using make screen to measure the penetration duration time at each layered plate. In 3-layered laminated RHA/mild steel/ A1 7039 plate, we observed that spall had occured around the back face of A1 7039 plate by the stress wave interaction. Through the comparison between theoretical and experimental data including Lambert's results, we conform that our study has good confidences.