• Fashion & Textile Research Journal
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• v.16 no.6
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• pp.979-986
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• 2014

This study establishes basic data for operations management by organizing processes and measuring time in the mini line for female jackets to improve productivity, ensure competitiveness, and maintain operator competency and the line process flow balance between apparel manufacturing companies. The results of this study are as follows. Sewing operations are divided into preparation functions, arrangement, partial tasks, and assembly that consist of 84 processes. The results from time measurement indicate that 3238.41seconds (sec) were required to produce a single jacket and that the average time required for operators was 231.32 sec. A control limit was established to increase the reliability of the measured value for net time. After outside values were removed, the operation time was measured to be 3176.35 sec. This accounted for 98.08% of the total operation time, with net time decreasing by 62.06. Skill and effort level coefficients were applied to measure the operator performance, the total real time was calculated to be 3415. The requirement for preparation and arrangement operations were 1233.35 sec, and 2182.22 sec for partial tasks and assembly operations. Process separation and organization were performed after the bottleneck operation was selected to identify the maximum line balance. Consequently, process efficiency of preparation and arrangement operations increased from 79.19% to 93.00%, and the partial tasks and assembly operations increased from 62.36% to 90.93%.

• Korean Journal of Plant Resources
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• v.20 no.1
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• pp.63-68
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• 2007

The purpose of this study was to applicate fundamental data for breeding new cultivar through selection of superior individuals and to investigate its nut characteristics in walnut hybrids. Selection of superior individuals with good nut qualities including high nut weight (NWT, >13g) and percentage of weight relative to total weight of nut (PWR, >50%) was carried out and then 4 promising individuals ($Sansung 4{\times}Concord-8,\;Concord{\times}Sansungl,\;Concord{\times}Sansung4\;and\;McKinster{\times}Punghan1$) were selected by quantitative characters. Especially width of pad of suture was main factor in selection of nut with high PWR (percentage of weight relative to total weight of nut) In addition, kernel length showed high correlation with kernel and nut weight. Thickness of septem (TOP) also had an effect on ease of kernel removal (EKR). In qualitative characters, there is a great difference among the individuals and cross combinations as well as showed simultaneously various characteristics in the same individual.

• Journal of the Korean Society for Marine Environment & Energy
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• v.13 no.2
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• pp.91-98
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• 2010

The water elevation inside the air chamber and bi-directional air flow in the duct of Oscillating Water Column wave energy converter is one of the most important factors to evaluate the operating performance. The numerical wave tank based on the commercial software Fluent 6.2 in the present paper is employed to generate the incident waves. The numerical wave tank consists of the continuity equations, the Reynolds-averaged Navier-Stokes equations and the two-phase VOF function. The oscillating amplitude of water column in the chamber and bi-directional air flow in the duct installed on the top of the chamber are calculated, and compared with experimental data to verify the validation of the present NWT. The nozzle effects of the chamber-duct system on the relative amplitudes of the inner free water surface and air flow rate in the duct are investigated.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.4
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• pp.497-502
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• 2013

In this study, the interlaminar fracture toughness in mode I of a hybrid composite inserted with different types of non-woven tissues was determined. The interlaminar fracture toughness in mode I is obtained by a double cantilever beam test. The experiment is performed using three types of non-woven tissues: 8 $g/m^2$ of carbon tissue, 10 $g/m^2$ of glass tissue, and 8 $g/m^2$ of polyester tissue. Considering a specimen with no non-woven tissue as a reference, the interlaminar fracture toughness in mode I of specimens inserted with non-woven carbon and glass tissues decreases by as much as 6.3% and 11.4%, respectively. However, the fracture toughness of a hybrid composite specimen inserted with non-woven polyester tissue increases by as much as 69.4%. It is considered that the specimen inserted with non-woven polyester tissue becomes cheaper, and lighter, and the value of the fracture toughness becomes much greater than that of the non-woven carbon tissue.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2019.11a
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• pp.150-152
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• 2019

In this study, the effects of the wave field changes due to the coastal structure on the hydrodynamic performance of the OWC wave energy, converter are analyzed using a three-dimensional numerical wave tank technique (NWT). The OWC device is simulated numerically by introducing a linear pressure drop model, considering the coupling effect between the turbine and the OWC chamber in the time domain. The flow distribution around the chamber is different due to the change of reflection characteristics depending on the consideration of the breakwater model. The wave energy captured from the breakwater is spatially distributed on the plane of the front of the breakwater, and the converted pneumatic power increased when concentrated in front of the chamber. The change of the standing wave distribution is repeated according to the relationship between the incident wavelength and the length of the breakwater, and the difference in energy conversion performance of the OWC was confirmed.