• Journal of the Korea Fashion and Costume Design Association
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• v.19 no.4
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• pp.93-104
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• 2017

This study is a basic study to develop shoe last design technology to enhance and revitalize the competitiveness of the handmade shoes. In-depth interviews were conducted with four manufacturers in Seongsu-dong to identify the production status and design technology of shoe lasts. The result of the research is as follows. Firstly, shoe lasts for adults are produced at intervals of 5mm between 245mm-285mm for men's shoes, and between 220-260mm for women's shoes. The production rate of women's shoes was high in the order of general type, boot type, and sandal type while men's shoes mainly produce general type. Secondly, the master last size and ball girth rating for men's and women's shoes were analyzed to EE-EEE grade at 260mm and D grade at 235mm. The length of the master last for men's shoes is 276-290mm, the heel width is 60-65mm, the ball width is 88-90mm, the ball girth is 250mm, and the waist girth is 248mm. The length of the master shoe last for women's shoes is 236-245 mm, the heel width is 50-55mm, the ball width is 78-80mm, the ball girth is 211~213mm, and the waist girth is 213~215mm. Thirdly, the last grading deviation is 5mm in length, the heel width is 0.5mm, the ball girth is 3.5mm, and the ball with is 1.2mm. The ball girth dimensions of Oxford type, slip-on type, and sneakers type are made at 250mm, 248mm, and 245mm for men's shoes. For women's shoes, the ball girth dimensions of pump type, loafer & boot type, and sandal type are made at 211~213mm, 214~215mm, and 211mm. Fourthly, t+he construction of the automation system is insufficient and almost completely depends on manual production.

• International Journal of High-Rise Buildings
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• v.9 no.2
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• pp.187-195
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• 2020

As deep decks are commonly used in construction fields and high-rise building. etc, the slim floor system is increasingly employed. But, the drawback of the slim floor system is that the use of 250 mm deep decks in a structure having a clear span of more than 6 m because of deflection and flexural buckling. This study suggests a non-support construction method where tendons are installed in the deep decks of the slim floor structure to introduce preload in order to control deflection in a structure having a clear span of 9 m. Loading tests were conducted to verify the composite effect and flexural capacity of the preloaded deep deck composite slab and evaluate the serviceability of the supportless construction method. The results showed the complete composite behavior of the preloaded deep deck composite slab with tendons. The specimens satisfied deflection limit and the working load was approximately 25% of the maximum load capacity. It is deemed that the cross-sectional area and yield strength of the deck plate should be taken into account in slab design and the yield strength and diameter of the tendon should be determined with the pre-tension taken into consideration.

• Journal of Welding and Joining
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• v.20 no.6
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• pp.59-59
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• 2002

Sn-Ag-Cu solder is known as most competitive in many kinds of Pb-free solders. In this study, effects of solderability with plated layers such as Cu, Cu/Sn, Cu/Ni and Cu/Ni/Au were investigated. Sn-3.5Ag-0.7Cu solder balls were reflowed in commercial reflow machine (peak temp. : 250℃ and conveyer speed : 0.6m/min). In wetting test, immersion speed was 5mm/sec., immersion time 5sec., immersion depth 4mm and temperature of solder bath was 250℃. Wettability of Sn-3.5Ag-0.7Cu on Cu, Cu/Sn (5㎛), Cu/Ni (5㎛), and Cu/Ni/Au (5㎛/500Å) layers was investigated. Cu/Ni/Au layer had the best wettability as zero cross time and equilibrium force, and the measured values were 0.93 sec and 7mN, respectively. Surface tension of Sn-3.5Ag-0.7Cu solder turmed out to be 0.52N/m. The thickness of IMC is reduced in the order of Cu, Cu/Sn, Cu/Mi and Cu/Ni/Au coated layer. Shear strength of Cu/Ni, Cu/Sn and Cu was around 560gf but Cu/Ni/Au was 370gf.

• Journal of Welding and Joining
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• v.20 no.6
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• pp.783-788
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• 2002

Sn-Ag-Cu solder is known as most competitive in many kinds of Pb-free solders. In this study, effects of solderability with plated layers such as Cu, Cu/Sn, Cu/Ni and Cu/Ni/Au were investigated. Sn-3.5Ag-0.7Cu solder balls were reflowed in commercial reflow machine (peak temp.:$250^{\circ}C$and conveyer speed:0.6m/min). In wetting test, immersion speed was 5mm/sec., immersion time 5sec., immersion depth 4mm and temperature of solder bath was $250^{\circ}C$. Wettability of Sn-3.5Ag-0.7Cu on Cu, Cu/Sn ($5\mu\textrm{m}$), Cu/Ni ($5\mu\textrm{m}$), and Cu/Ni/Au ($5\mu\textrm{m}/500{\AA}$) layers was investigated. Cu/Ni/Au layer had the best wettability as zero cross time and equilibrium force, and the measured values were 0.93 sec and 7mN, respectively. Surface tension of Sn-3.5Ag-0.7Cu solder turmed out to be 0.52N/m. The thickness of IMC is reduced in the order of Cu, Cu/Sn, Cu/Mi and Cu/Ni/Au coated layer. Shear strength of Cu/Ni, Cu/Sn and Cu was around 560gf but Cu/Ni/Au was 370gf.

• Journal of Korea Water Resources Association
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• v.56 no.10
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• pp.655-665
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• 2023

In this study, unit hydrographs are calculated when precipitations of 10 scales instantaneously occurs in a virtual watershed with a constant slope and roughness. Then, the relationship between the peak flow rate and the peak occurrence time of the unit hydrograph was calculated for the precipitation scale, respectively. At this time, the virtual watershed simplified with a rhombic shape, a constant slope, and a flow condition with a certain roughness was applied instead of a natural watershed in order to understand the effect the precipitation scale has on the peak value of the unit hydrograph. And it was assumed that the precipitation in the basin was effective rainfall and the runoff was direct runoff, and the runoff flowed in a straight, uniform flow from the drop point to the outlet. The relationship between the peak flow and the peak occurrence time of the unit hydrograph was calculated in the case of 10 types of precipitation scales of 10 mm, 40 mm, 90 mm, 160 mm, 250 mm, 360 mm, 640 mm, 1,000 mm, 1,210 mm, and 1,690 mm of effective precipitation. A noteworthy achievement of this study is that, even without the storage effect of the watershed, as the scale of precipitation increases, the depth of runoff increases, so the flow rate in the watershed increases and the distance per unit time increases, so the peak flow rate increases and the peak occurrence time increases. This is a nonlinear characteristic of watershed runoff.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.44 no.4
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• pp.362-369
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• 2008

The snow melting system by electric heating wires which is adopted in this research is a part of road facilities to keep surface temperature of the road higher than freezing point of water for melting the snow accumulated on it. The electric heating wires are buried under paved road at a certain depth and operated automatically and manually. Design theory, amount of heating, and installation standard vary according to economic situation, weather condition, installation place and each country applying the system. A main purpose of this study is figuring out the appropriate range of required heat capacity and installation depth and pitch for solving snowdrifts and freezing problems with minimum electric power consumption. This study was performed under the ambient air temperature($-2^{\circ}C$, $-5^{\circ}C$), the pitches of the electric heating wires(200 mm, 300 mm), heating value($250\;W/m^2$, $300\;W/m^2$, $350\;W/m^2$).

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.706-713
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• 2002

In the multi-pass welding of pressure vessels or ships, the mechanical touch sensor system is generally used together with a manipulator to measure the gap and depth of the narrow gap to perform seam tracking. Unfortunately, such mechanical touch sensors may commit measuring errors caused by the eterioration of the measuring device. An automation system of narrow gap multi-pass welding using a laser vision system which can track the seam line of narrow gap and which can control welding power has been developed. The joint profile of the narrow gap, with 250mm depth and 28mm width, can be captured by laser vision camera. The image is then processed for defining tracking positions of the torch during welding. Then, the real-time correction of lateral and vertical position of the torch can be done by the laser vision system. The adaptive control of welding conditions like welding Currents and welding speeds, can also be performed by the laser vision system, which cannot be done by conventional mechanical touch systems. The developed automation system will be adopted to reduce the idle time of welders, which happens frequently in conventional long welding processes, and to improve the reliability of the weld quality as well.

• International Journal of Korean Welding Society
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• v.2 no.1
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• pp.45-51
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• 2002

In the multi-pass welding of pressure vessels or ships, the mechanical touch sensor system is generally used together with a manipulator to measure the gap and depth of the narrow gap to perform seam tracking. Unfortunately, such mechanical touch sensors may commit measuring errors caused by the deterioration of the measuring device. An automation system of narrow gap multi-pass welding using a laser vision system which can track the seam line of narrow gap and which can control welding power has been developed. The joint profile of the narrow gap, with 250mm depth and 28mm width, can be captured by laser vision camera. The image is then processed for defining tracking positions of the torch during welding. Then, the real-time correction of lateral and vertical position of the torch can be done by the laser vision system. The adaptive control of welding conditions like welding currents and welding speeds, can also be performed by the laser vision system, which cannot be done by conventional mechanical touch systems. The developed automation system will be adopted to reduce the idle time of welders, which happens frequently in conventional long welding processes, and to improve the reliability of the weld quality as well.

• Journal of the Korean Geosynthetics Society
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• v.15 no.4
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• pp.97-104
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• 2016

This paper performed consolidation tests on soft ground with and without artesian pressure conditions to find out characteristics of leaching effects using two types of one-dimensional column equipment(height : 1,100mm, outer diameter : 250mm). Artesian pressure of 5.5kPa was applied to the bottom of soft ground inside column equipment. Distribution of salinity and shear strength with soil depth were measured after the consolidation test. From the results, it was found that distribution of undrained shear strength and salt concentrations were similar at the top of clay ground irrespective of artesian pressure condition. However, at the bottom of clay ground, the values of undrained shear strength and salt concentration under artesian pressure were lower than those without artesian pressure. This result indicates that structure of soft soil with artesian pressure was weakened by salt leaching. Electronic resistance results showed that void ratio under artesian pressure condition was more reduced than that without artesian pressure condition.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2000.10a
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• pp.168-173
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• 2000

The limiting drawing ratio (LDR) under uniform heating of blanks was measured at the various temperature ranges between 25 and $250^{\circ}C$ by using two different blank shapes, square and circular blanks, and six different blank sizes with the drawing ratios(DR) of 2.4 to 2.9. The galvannealed steel sheet (SCP3CM 60/60) of 0.7mm thickness was used. The LDR at warm forming condition reached 1.2 times of that at room temperature, and the maximum drawing depth reached 1.9 times. The higher temperature was adopted, the more stable and uniform thickness strain distribution was observed.