• Journal of the Korean Society for Precision Engineering
• /
• v.31 no.5
• /
• pp.381-387
• /
• 2014

This paper introduces a system to machine micro-sized patterns effectively on surface based on micro-milling process using tools with simultaneous rotation and oscillation, oscillation micro milling. To review the effectiveness of proposed concept, we integrated a micro-spindle supported by active magnetic bearings with a precision 3-axis air bearing stage using double-wedge mechanism, and tested this oscillation milling. Two types of oscillation milling were tested, which are linear oscillation milling with a flat end mill and elliptical oscillation milling with a ball end mill with 0.3 mm of diameter. The spindle was rotating 110 krpm and workpiece was moving constant speed of 2~8 mm/sec during the oscillation milling. As the results, multiple oval shape dimples were generated in regular spacing, and the variation of elliptical motion made different shapes of patterns. The results showed that proposed oscillation milling can be successfully used for machining repeated micro-patterns.

• Journal of the Korea Fashion and Costume Design Association
• /
• v.23 no.2
• /
• pp.79-91
• /
• 2021

This study aims to rectify the disfigurement of bowlegged, (which means they have a gap between knees due to knee joint problems) females in their twenties through the development of pants patterns. The contents of the study are as follows: First, two types of basic pattern-making methods were selected. Two mock-ups, which were made by using these pre-selected basic patterns, were worn by three bowlegged participants and evaluated with a fit test. A basic pattern, which had good body fit was selected, which had a bubble or a wedge at in crotch area and roomy or snug upper thigh. Second, the mock-up, which was made by using the selected basic pattern, led to the outward movement of crease lines. Two types of patterns that were adjusted were evaluated through a fit test. As a result, an effective adjustment for moving the crease line to the outside or to the center was to cut along the slash line of a horizontal balance line to, but not through the crotch seam to spread the pattern at the hip. Third, three patterns were readjusted using the chosen alteration pattern, and the crotch seam and spread patterns of 1 cm, 2 cm, and 3 cm at the hip were applied. As a result of the evaluation of the fit test, three participants-the majority-showed a better fit when the spread amount in the pattern was 2 cm, although every participant did have a different gap between the knees. This study has significance in which rectifies the disfigurement of bowlegged individuals through the development of patterns for females in their twenties who are bowlegged.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.32 no.4
• /
• pp.215-222
• /
• 2019

The heat conduction problem with discontinuous material coefficients generally consists of the conservative equation, boundary condition, and interface condition, which should be additionally satisfied in the solution procedure. This feature often makes the development of new numerical schemes difficult as it induces a layered singularity in the solution fields; thus, a special approximation is required to capture the singular behavior. In addition to the approximation, the construction of a total system of equations is challenging. In this study, a wedge function is devised for enriching the approximation, and the interface condition itself is embedded in the moving least squares(MLS) derivative approximation to consistently satisfy the interface condition. The heat conduction problem is then discretized in a strong form using the developed derivative approximation, which is named as the interface immersed MLS difference method. This method is able to efficiently provide a numerical solution for such interface problems avoiding both numerical quadrature as well as extra difference equations related to the interface condition enforcement. Numerical experiments proved that the developed numerical method was highly accurate and computationally efficient at solving the heat conduction problem with interfacial jump as well as the problem with a geometrically induced interfacial singularity.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
• /
• 2003.04a
• /
• pp.363-368
• /
• 2003

We have successfully developed a more effective algorithm to extract the lineament in the area covered by wide alluvial deposits characterized by a relatively narrow range of brightness in the Landsat TM image, while the currently used algorithm is limited to the mountainous areas. In the new algorithm, flat areas mainly consisting of alluvial deposits were selected using the Local Enhancement from the Digital Elevation Model (DEM). The aspect values were obtained by 3${\times}$3 moving windowing of Zevenbergen & Thorno's Method, and then the slopes of the study area were determined using the aspect values. After the lineament factors in the alluvial deposits were revealed by comparing the threshold values, the first rank lineament under the alluvial deposits were extracted using the Hough transform In order to extract the final lineament, the lowest points under the alluvial deposits in a given topographic section perpendicular to the first rank lineament were determined through the spline interpolation, and then the final lineament were chosen through Hough transform using the lowest points. The algorithm developed in this study enables us to observe a clearer lineament in the areas covered by much larger alluvial deposits compared with the results extracted using the conventional existing algorithm. There exists, however, some differences between the first rank lineament, obtained using the aspect and the slope, and the final lineament. This study shows that the new algorithm more effectively extracts the lineament in the area covered with wide alluvlal deposits than in the areas of converging slope, areas with narrow alluvial deposits or valleys.