• Journal of the Korean Society for Precision Engineering
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• v.11 no.5
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• pp.171-179
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• 1994

For successful implementation of robotic painting system, a structured design and analysis procedure is necessary. In designing robotic system, both functional and economical feasibility should be investigated. As the robotization is complicated task involving implemen- tation details (such as robot selection, accessory design, and spatial layout) together with operation details, the computer aided design and analysis method should be sought. However, conventional robotic design systems and off-line programming systems cannot accommodate these inquiries in a unified fashion. In this research, we develop an interactive design support system for robotization of a cycle painting line. With the developed system called SPRPL (Simulation Package for Robotic Painting Line) users can design the painting objects (via FRAME module), select robot model (ROBOT), design the part hanger (FEEDER), and arrange the workcell. After motion programming (MOTION), the design is evaluated in terms of: a) workpace analysis, b) coating thickness analysis, and c) cycle time (ANALYSIS).

• Journal of the Korea Concrete Institute
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• v.13 no.1
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• pp.46-53
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• 2001

Two full scale precast pretensioned dapped ended rectangular beams designed by PCI design handbook for a major domestic live load of market and parking building - 500kgf/㎡ and 1,200kgf/㎡ were investigated experimentally. The bottom length of beams was 60cm which was same to the length of rectangular column in the base of five-story market or parking buildings. The height of dap was web hight plus half of the flange height within the allowable limit of PCI method. Shear tests were performed on four beam ends. Followings were obtained from the experimental study. All of the specimens were fully complied with the PCI design handbook. Two of four specimens which were designed for live load of 1,200kgf/㎡ showed crackings at the re-entrant corner of dap before the full service loadings, and failed by direct shear at the load level much less than their calculated nominal strength. The specimens designed for live load of 1,200kgf/㎡ failed at 772 tonf and 78.36tonf by direct shear crackings. This strength was less than PCI limit of 81.9 tonf and higher than ACI limit of 65.62tonf. Thus, the limit suggested by ACI seems more reasonable in regard of safety in view of this test results. According to load-strain curves, the strain of hanger reinforcement reached almost yield strain. It is recommended to use more inclined hanger reinforcement of improve the strength and serviceability.

• Journal of the Korea Safety Management & Science
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• v.21 no.4
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• pp.75-80
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• 2019

Sales of the Korean clothing industry grew to 16.9 percent on-year in 2010, but the growth rate dropped to 3 percent from 2011 to 2016 and the overall market began to slump to 1.1.6 percent in 2017. The competitiveness of clothing companies is also a major sector in logistics capability, and the average logistics cost of domestic clothing companies is 8.3 percent of sales in 2011, higher than the average 8 percent of domestic industries, and 36.4 percent of the total storage cost in 2011, higher than the 28.8 percent share of the total storage cost of domestic companies. As domestic production conditions such as wage hikes and labor disputes worsened in the 1990s, production facilities were rapidly moved overseas, which led many clothing companies to have no production facilities or a minimal production base in Korea and focus on marketing and design capabilities. The total storage capacity and storage efficiency of the logistics center became very important as the products were changed to the form of mass warehousing and small-volume forwarding. Research shows that building column spacing, a model of this research, can affect the amount of hanger rack storage empirically, so for sustainable growth of clothing companies, it is necessary to improve competitiveness in the logistics market by reducing costs and improving efficiency to overcome difficulties in corporate management. Because logistics costs are 8.3 percent and operating profit to sales ratio is 2 percent, it is expected that operating profit will increase by 41.5 percent if logistics costs are reduced by 10 percent. If 10% of storage cost is saved based on storage cost, operating profit is expected to increase by 15% To strengthen the competitiveness of the clothing industry, a reduction in logistics costs is essential. Therefore, the purpose of this study is to provide hints that logistics experts can have empirically small amounts in reducing storage costs through column spacing adjustment of logistics centers that have not been dealt with statistically until now, and to contribute to the continued growth of clothing companies and the development of the domestic logistics industry.

• Earthquakes and Structures
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• v.23 no.4
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• pp.373-384
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• 2022

To improve the seismic performance of suspended ceiling structures, various vibration-damping devices have been developed. However, the devices made of metals have a limit in that they cause large deformation and seriously damages the exterior of the suspended ceiling structure from the wall. As a results, their strengthening effect of the suspended ceiling structure was minimal. Thus, this study employed a spring and vibration-proof rubber effectively controlled vibrations without increasing horizontal seismic loads on the ceiling to enhance the seismic resistance of suspended ceiling structures. The objective of the study is to examine the dynamic properties of a seismic damping-isolation unit (SDI) with various details developed. The developed SDI was composed of a spring, embossed rubbers, and prestressed bolts, which were the main factors enhancing the damping effect. The shaking table tests were performed on eight SDI specimens produced with the number of layers of embossed rubber (n_s), presence or absence of a spring, prestressed force magnitude introduced in bolts (f_ps), and mass weight (W_m) as the main parameters. To identify the enhancement effect of the SDI, the dynamic properties of the control specimen with a conventional hanger bolt were compared to those of the SDI specimens. The SDI specimens were effective in reducing the maximum acceleration (A_{c max}), acceleration amplification factor (α_p), relative displacement (δ_R), and increasing the damping ratio (ξ) when compared to the control specimen. The A_{c max}, α_p, and δ_R of the SDI specimens with two rubbers, spring, and f_ps of 0.1f_by, where f_by is the yielding strength of the screw bolt were 57.8%, 58.0%, and 61.9% lower than those of the conventional hanger bolt specimens, respectively, resulting in the highest ξ (=0.127). In addition, the α_p of the SDI specimens was 50.8% lower than those specified in ASCE 7 and FEMA 356. Consequently, to accurately estimate the α_p of the SDI specimens, a simple model was proposed based on the functions of f_ps, stiffness constant of the spring (K), W_m, and n_s.

• Journal of the Korean Society of Safety
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• v.19 no.2
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• pp.93-97
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• 2004

Slab formwork consists of sheathing, stringer, hanger and shore. There are several types of adjustable individual shores. In constructions site, pipe supports are usually used as shores. The strength of a pipe support is decreasing as it is frequently being used at the construction site. In this study, 2857 pipe supports were bought to fine out the strength change of used pipe support and unused pipe supports according to aging. Among these pipe supports, 2337 pipe supports were lent to the construction companies free of charge. Compressive strength was measured by knife edge test and plate test at each 3 month. Test results show that the strength of unused pipe supports almost equaled to the strength of new pipe supports until 191 days, but the strength of used pipe supports at 191 days was lower than the strength of new pipe supports. So, the strength of used pipe supports at 191 days was not satisfied the specification of KS F 8001. According to these results, it shows that attention has to be paid to formwork design using used pipe supports. Therefore, the paresent study results will be able to provide a firm base to design slab formwork and test the performance of used temporary structure and prevent formwork collapses.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.5
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• pp.688-694
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• 2018

The transition section of the overhead rigid conductor rail (ORCR) consists of a direct induction device and a limit point to prevent the power supply failure and failure of the electric railway vehicle pantograph due to the difference of the uplift in the catenary line. In T-Bar transition section, a twin simple catenary is mostly installed between the overhead catenary system (OCS) in the ground section and the ORCR in the underground section. In this paper, we compare and analyze the possibility of replacing the twin simple catenary with heavy simple catenary. The reliability of numerical analysis results was confirmed by comparing field test with numerical results. Comparing the numerical results of the twin simple catenary with the heavy simple catenary in the transition section, the difference uplift is 5.9[mm] on average. When applying heavy simple catenary instead of twin simple catenary, the slight difference of uplift can be compensated by adjusting the height of hanger-ear or support bracket.

• Journal of radiological science and technology
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• v.2 no.1
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• pp.23-29
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• 1979

Roentgenographic film has to be handled with greatest care during removal from the packing, loading of the cassettes and loading of the hanger. In the case of prior to or after exposed film is handled with mechanical pressure in darkroom, the most common phenomena are desensitization or sensitization on roentgenographic film. In order to observe these defect occurring on, it, the author studied on change of the densities where the mechanical pressure reached to the roentgenographic film. 1. The optimal minimum and maximum densities in routine chest x-ray film are from 0.25 to 1.47 2. The dependence of the desensitization occurring on film upon the bent degree of film is in the portion to bent degree over $10^{\circ}$ 3. Appearances of the desensitization on film by the curved degree of film is inverse proportion to it's degree below intervals of 3cm. 4. The more unexposed film is bent with nail tip and is pressured with palm, the more desensitization it was appeared upon film size and pressure weight. 5. The most serious area of desensitization produced by many types of mechanical pressure is in the portion of lung apex and outside lung fields. 6. The tendency of desensitization due to mechanical pressure on unexposed film is more serious than sensitization on exposed film in the view of radiologic diagnosis.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.395_396
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• 2009

This paper handles with effect of electromagnetic force on the cables by fault current accompanied by accident of underground transmission cable. Even though underground transmission cable is an essential transmission method to supply stable power for downtown and population center, interaction of electromagnetic force from fault current is very large comparing to overhead transmission line due to restricted installation space such as tunnel, etc. and close consideration is required for it. This paper describes the effect of electromagnetic force through results of three phase short-circuit test and electromagnetic force analysis using theoretical calculations and electrical evaluation test after three phase short-circuit test, which will be utilized as basic materials for improvement and development of cleat, hanger, etc. to reduce and release effect of electromagnetic force in the future.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.363_364
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• 2009

Even though underground transmission cable is an essential transmission method to supply stable power for downtown and population center, interaction of electromagnetic force from fault current is very large comparing to overhead transmission line due to restricted installation space such as tunnel, etc. and close consideration is required for it. This paper presents countermeasures to reduce and release the effect of electromagnetic force with rope binding and installation of spacer and describes its efficacy through three phase short-circuit test, which will be utilized as basic materials for improvement and development of cleat, hanger, etc. to reduce and release effect of electromagnetic force in the future.

• Transactions of the Korean Society of Automotive Engineers
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• v.2 no.3
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• pp.21-32
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• 1994

The Problem of mechanical vibration is investigated for an automotive exhaust system. The vibrational reduction effect is systematically evaluated according to the attachment of the exhaust system. Moreover, the optimal attachment position of bellows is determined from the viewpoint of vibration isolation. The structure is analysed by the finite element technique where the geometry, the mass, the stiffness and the damping properties of the exhaust pipe are modeled. The validity of the developed model is verified by comparing with the experimental results. An optimization is carried out by the quadratic approximation algorithm. The reaction transferred to an automobile body by the hanger is considered ad the objective function. It is shown that the exhaust system which has the bellows at the optimal position is more effective for the vibrational characteristics than the others. It is also proved that this analytical method is quite useful in the design stage of the exhaust system.