• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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• pp.739-742
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• 2000

From the experimental study of W-EDM for alloyed steel, the characteristics such as Hand Drum Form and surface roughness have been observed and evaluated for various conditions. In square hole, the increase of If as to made condition the calculate high value of surface roughness. Also compare dimensionless square hole with circle hole' graph. In circle hole, if a value of surface roughness IP 6 in a side of circle it show a 0.4${\mu}{\textrm}{m}$ and in IP 8, 0.6${\mu}{\textrm}{m}$, in IP 10, 0.7${\mu}{\textrm}{m}$, in IP 12. 0.8${\mu}{\textrm}{m}$ higher than before. This figure show the surface roughness is higher than before, because a table move in either X-axis or Y-axis in square hole, on the contrary, in circle there table move in X-axis and Y-axis at the same time. hand drum form getting small when wire tension increase 1000gf to 1500gf, at the same working conditions. the smaller of off time, the mailer of hand drum form in same condition and same wire tension. but if you compare square hole with circle hole' graph hand drum form displayed in maintained term of working condision, on the contrary, in case of square hole variation of hand drum form is more increase than a grow of IP

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.04a
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• pp.567-572
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• 2000

From the experimental study of W-EDM for alloyed steel, the characteristics such as Hand Drum Form and surface roughness have been observed and evaluated for various conditions. In square hole, the increase of IP as to made condition, the calculate high value of surface roughness. Also compare dimensionless square hole with circle hole' graph, In circle hole, if a value of surface roughness IP 6 in a side of circle it show a 0.4${\mu}{\textrm}{m}$ and in IP 8, 0.6${\mu}{\textrm}{m}$, in IP 10, 0.7${\mu}{\textrm}{m}$, in IP 12, 0.8${\mu}{\textrm}{m}$ higher than before. This figure show the surface roughness is higher than before, because a table move in either X-axis or Y-axis in square hole, on the contrary, in circle there table move in X-axis and Y-axis at the same time. hand drum form getting small when wire tension increase 1000gf to 1500gf, at the same working conditions. The smaller of off time, the maller of hand drum form in same condition and same wire tension. but if you compare square hole with circle hole' graph, hand drum form displayed in maintained term of working condision, on the contrary, in case of square hole variation of hand drum form is more increase than a grow of IP

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.721-724
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• 1998

A circular image in a space don't appear as an exact circular image and appear as an oval in image buffer because distortion of camera lens, number of horizontal pixel of CCD photographing element and unmber of horizontal pixel of image buffer are not in accordance. By using familiar 3-D coordinate, know as circle's diameter, and cicle's center, you correct a pin-hole camera and get an exact circle with reprojection a circle into image buffer, according to a perspective.

• Journal of the Korean Vacuum Society
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• v.12 no.4
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• pp.288-292
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• 2003

The fabrication of silicon nano-master with pillar structures using E-beam lithography and ICP etching was investigated for application of 2-dimensional polymer photonic crystal waveguides with air hole structures. Pillar structures with square, hexagon, dodecagon and circle were successfully fabricated. The diameters and structures of fabricated pillars were measured by CD-SEM and SPM-AFM. It was found that the optimal dose for complete circle pillar structures was 432 $\mu$C/$\textrm{cm}^2$.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.8 no.1
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• pp.81-92
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• 2004

Muskhelishvili's complex variable method has been applied to derive exact and closed expressions for Gaursat's functions for the first and second fundamental problems of the infinite plate weakened by a curvilinear hole which is conformally mapped on the domain outside the unit circle by means of rational mapping function. The hole having three poles. The previous work of the authers in this domain is considered as special cases of this work.

• Radiation Oncology Journal
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• v.7 no.2
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• pp.299-303
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• 1989

Authors have developed highly reproducible calibration method for the Micro-Selectron HDR Ir-192 system (Nucletron, Motherland). The new jig has a 10cm radius circular hole in the $30cm{\times}30cm{\times}0.2cm$ acrylic plate, and 5F flexible bronchial tubes are attached around the hole. The source moves along the circle in the tubes and the ionization chamber is placed verticaly at the center of the circular hole (center of the jig). Dose distribution near the center was derived theoretically, and measured with the film dosimetry system. Theoretical calculation and measurement show the error margin below $0.1\%$ for 1mm or 2mm position deviation. We have measured at 12 and 24 points of circle with 1, 6, 11 and 21 second dwell time of source in order to calculate the activity of the source. Measurements have been repeated daily for 50 days. The accuracy and the reproducibility are below $1\%$ error margin. The half life of the source from our measurement is estimated $73.4\pm0.4$ days.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.5
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• pp.126-133
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• 2017

This report investigates the stress distribution according to the location and shape change of the circular hole for the lightweight design of the cross beam of a railway passenger car and studies the lightweight design. To design a lightweight cross beam with a circular hole, we selected the non-circular crossbeam as a basic model, examined the stress distribution and displacement by position and determined the location, shape, size and quantity of the hole for light weight. We analyzed the effects of the position and shape of the hole on the maximum equivalent stress and displacement. The influencing factors were set as the design parameters, and the stress value was examined according to the variation of each variable. By considering the stress value according to the change of each variable and selecting the design parameter with the narrowest scattering value of the stress at each position of the hollow cross beam with various hole positions and shapes, we studied a cross beam with a circle hole under identical load condition to have an equal stress distribution to that of a non-circular cross beam.

• Proceedings of the KWS Conference
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• 2007.11a
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• pp.218-221
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• 2007

The surface mounting technology of 0402 electric chip part is necessary to fabricate a high density and multi-functional module, but there is a limitation of the technology, like as a bridge and self-alignement. This work estimated SMT processing factors of 0402 chip. To obtain optimum SMT process, we evaluated effects of stencil thickness, shape of hole on printability and mountability. Printability shows best results under the thickness of $80{mu}m$ with circle hole shape and 90% square hole shape. In case of chip mounting process, chip mis-alignment and bridge was occurred rarely in same conditions. In more thin stencil thickness, $50{mu}m$, strength of 1005 chip parts was poor, because of amount of printed solder was insufficient.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.3
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• pp.1650-1669
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• 2017

In this study, each pixel in an ear is used as a centroid to generate a cake. Subsequently the major axis length of this cake is computed and obtained. This obtained major axis length serves as a feature to recognize an ear. Later, the ear hole is used as a centroid and a 16-circle template is generated to extract the major axis lengths of the ear. The 16-circle template extracted signals are used to recognize an ear. In the next step, a ring-to-line mapping technique is used to map these major axis lengths to several straight-line signals. Next, the complex plane vector computing technique is used to determine the similarity of these major axis lengths, whereby a solution to the image-rotating problem is achieved. The aforementioned extracted signals are also compared to the ones that are extracted from its neighboring pixels, whereby solving the image-shifting problem. The algorithm developed in this study can precisely identify an ear image by solving the image rotation and image shifting problems.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.2
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• pp.195-201
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• 2012

According to many customers' requests, optical measurement module (OMM) applications using automatic measuring devices to measure the machined part rapidly on a machine tool have increased steeply. Touch trigger probes are being used for job setup and feature inspection as automatic measuring devices, and this makes quality checking and machining compensation possible. Therefore, in this study, the use of touch trigger probes for accurate measurement of the machined part has been studied and a macro program for a hole measuring cycle has been developed. This hole is the most common feature to be measured, but conventional methods are still not free from measuring error. In addition, the eccentricity change of the least square circle was simulated according to the roundness error in a hole measurement. To evaluate the reliability of this study, the developed hole-measuring program was executed to measure the hole plate on the machine and verify the roundness error in the eccentricity simulation result.