• Journal of the Korean Society of Clothing and Textiles
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• v.30 no.6 s.154
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• pp.870-879
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• 2006

In this study, the difference in the mechanical properties of silver and cotton weft knitted fabrics was studied. Six silver fabrics for the summer ladies' knit outwear were knitted varying knit structure and fabric density. Two commercial cotton knitted fabrics were selected to compare the properties. subjective sensation of hand of the fabrics was also studied. Mechanical properties of the fabric samples were measured by KES-FB system. From these, primary hand values(HV) were evaluated by the conversion equation (KW-403-KTU) and the total hand value(THV) was carried out according to the KW-304 Summer. The result of the research show that silver weft knitted fabrics had lower LT, RT, G, 2HG and higher EM, W, LC, WC, RC than cotton weft knitted fabrics. The use of silver yam contributed to increase in surface roughness of knitted fabrics. As the silver knitted fabrics became thicker compressional energy increased. The use of silver yarns contributed to much better fabric handle compared with the use of cotton yam only. It appeared that coefficient of friction of tuck stitch was larger than that of plain and interlock stitch. KOSHI and FUKURAMI values of the tuck samples were significantly higher than those values of the plain and interlock samples, while SHARI values were low in general. The total hand value of tuck stitch was higher than those of interlock and plain stitch.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.10a
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• pp.163-166
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• 2004

Epoxy composite reinforced with 3-D braided Glass/Aramid hybrid fabric was fabricated. FBG sensor was embedded along the braid yam in order to monitor the changes of the complicated inner region of the 3-D braid structure. The good linearity between Bragg wavelength and temperature was verified by several preliminary experiments. The strain inside 3-D braided beam was estimated using FBG sensor system, and the result was compared with the calculated value. It was found that FBG sensor system is very useful technique to investigate inside region of complicated structure.

• Proceedings of the Korean Reliability Society Conference
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• 2005.06a
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• pp.131-137
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• 2005

In this paper, we propose a Bayesian approach to determine the adaptive preventive maintenance(PM) policy for a general sequential imperfect PM model proposed by Lin, Zuo and Yam(2000) that PM not only reduces the effective age of the system but also changes the hazard rate function. Assuming that the failure times follow Weibull distribution, we adopt a Bayesian approach to update unknown parameters and determine the Bayesian optimal sequential PM policies. Finally, numerical examples of the optimal adaptive PM policy are presented for illustrative purposes.

• International Journal of Control, Automation, and Systems
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• v.4 no.6
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• pp.763-768
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• 2006

The two-for-one(TFO) twister is precision machinery that twists fibers rapidly under constant tension. Since the quality of the twisted yarn is directly deteriorated by faults of the twister, such as the distortion of the spinning axis, bearing abrasion, and tension irregularity, it is important to detect faults of the TFO twister at an early stage. In this research, a new algorithm is proposed to detect faults of the TFO twister and their causes, by measuring the vibrations of the TFO twister and obtaining frequency components with a FFT algorithm. The TFO twister with faults showed increased vibrations and each fault generated vibrations at different frequencies. By analyzing changes of characteristics of vibrations, we can determine faulty twisters. The proposed fault detection algorithm can be implemented cheaply with a signal processor chip. It can be used to find when to repair a faulty TFO twister without much loss of yam on-line.

• Steel and Composite Structures
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• v.22 no.3
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• pp.589-611
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• 2016

The primary objectives of this research are to investigate the energy factor response of steel moment resisting frame (MRF) systems equipped with fuses subject to ground motions and to develop an energy-based evaluation approach for evaluating the damage-control behavior of the system. First, the energy factor of steel MRF systems with fuses below the resilience threshold is derived utilizing the energy balance equation considering bilinear oscillators with significant post-yielding stiffness ratio, and the effect of structural nonlinearity on the energy factor is investigated by conducting a parametric study covering a wide range of parameters. A practical transformation approach is also proposed to associate the energy factor of steel MRF systems with fuses with classic design spectra based on elasto-plastic systems. Then, the energy balance is extended to structural systems, and an energy-based procedure for damage-control evaluation is proposed and a damage-control index is also derived. The approach is then applied to two types of steel MRF systems with fuses to explore the applicability for quantifying the damage-control behavior. The rationality of the proposed approach and the accuracy for identifying the damage-control behavior are demonstrated by nonlinear static analyses and incremental dynamic analyses utilizing prototype structures.

• Horticultural Science & Technology
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• v.31 no.3
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• pp.289-298
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• 2013

Effects of curing treatments and storage temperature on the quality of Chinese yams (Dioscorea polystachya Turcz.) were investigated stepwise in three consecutive years for the optimization of postharvest handling procedures. Tuberous roots were harvested in early to mid November and cured under ambient or $29^{\circ}C$ heated air conditions for various periods according to the treatment conditions. Storage temperatures in the range of 0.5 to $7.5^{\circ}C$ were phased in to avoid chilling injury while examining storage potential from 4 to 7 months. As poststorage technology, short-term $60^{\circ}C$ hot-air exposure or low shelf temperature treatments were additively imposed. Curing treatments, especially heated air curing for 3-5 days tended to reduce the respiration and weight loss during storage while maintaining flesh firmness. Storage at $0.5^{\circ}C$ brought out typical chilling injury symptoms on the shelf with increases in respiration and lower flesh firmness by tissue breakdown resulting in the rapid loss of marketability. Optimum storage temperature appeared to be the $3-4^{\circ}C$ range which suppresses quality deterioration while avoiding chilling injury. Low shelf temperature seemed to be a necessary part of postharvest handling system to keep marketability through control of poststorage disorders such as rooting and decay. Overall results suggested that optimized postharvest program consisting of heated-air curing, storage at $3-4^{\circ}C$, and low shelf temperature could extend storage potential of Chinese yam to longer than 7 months.

• Fibers and Polymers
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• v.6 no.2
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• pp.169-173
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• 2005

Low temperature plasma (LTP) treatment was applied to wool fabric with the use of a non-polymerizing gas, namely oxygen. After the LTP treatment, the fabric properties including low-stress mechanical properties, air permeability and thermal properties, were evaluated. The low-stress mechanical properties were evaluated by means of Kawabata Evaluation System Fabric (KES-F) revealing that the tensile, shearing, bending, compression and surface properties were altered after the LTP treatment. The changes in these properties are believed to be related closely to the inter-fiber and inter-yam frictional force induced by the LTP. The decrease in the air permeability of the LTP-treated wool fabric was found to be probably due to the plasma action effect on increasing in the fabric thickness and a change in fabric surface morphology. The change in the thermal properties of the LTP-treated wool fabric was in good agreement with the above findings and can be attributed to the amount of air trapped between the yams and fibers. This study suggested that the LTP treatment can influence the final properties of the wool fabric.

• Structural Engineering and Mechanics
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• v.82 no.5
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• pp.611-628
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• 2022

Energy-dissipative rocking (EDR) columns are a class of seismic mitigation device capable of dissipating seismic energy and preventing weak-story failure of moment resisting frames (MRFs). An EDR consists of two hinge-supported steel columns interconnected by steel dampers along its height. Under earthquakes, the input seismic energy can be dissipated by plastic energy of the steel dampers in the EDR column. However, the unrecoverable plastic deformation of steel dampers generally results in residual drifts in the structural system. This paper presents a proof-of-concept study on an innovative device, namely self-centring energy-dissipative rocking (SC-EDR) column, aiming at enabling self-centring capability of the EDR column by installing a set of shape memory alloy (SMA) tension braces. The working mechanism of the SC-EDR column is presented in detail, and the feasibility of the new device is carefully examined via experimental and numerical studies considering the parameters of the SMA bar diameter and the steel damper plate thickness. The seismic responses including load carrying capacities, stress distributions, base rocking behaviour, source of residual deformation, and energy dissipation are discussed in detail. A rational combination of the steel damper and the SMA tension braces can achieve excellent energy dissipation and self-centring performance.

• Fashion & Textile Research Journal
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• v.4 no.3
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• pp.248-253
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• 2002

The purpose of this study was to improve consumer sleeping life in quality and to suggest producers meet new consumer needs and demands, by examining the nationwide use of bedding, analyzing consumer sleeping life by category and age group, comparing the results with the findings of the nationwide studies by Sung Su-kwang (1992) and Lee Song ja (1995), and identifying the major trend of consumer sleeping life. Results and Discussion The findings of this study were as below: 1. The General Characteristics of the Subjects : Most of the housewives investigated were in their 30s and 40s, with 41.7% and 50.8% respectively. 2. Bedroom : When it comes to bedroom style, 47.8% put beds in their rooms with the Korean under-floor heating system, and 45.4% didn't place beds in their rooms with the same heating system. 3. The Purchase of Bedding : 49.0%, approximately half the homemakers, bought their current bed-clothes at bedding shops, and just 3.2% made them on their own at home. 4. The Use of Bedclothes : In summer, yam (flax, ramie fabric) and a single-layer bed sheet (41.9%) were in use most, followed by a single-layer quilt (34.5%). 5. Bedding Management The most common frequency of bedding disinfection by sunning was once a month (29.4%), followed by once per two weeks (23.9%) and once a week (19.0%) in the order named.

• Journal of the Korea Fashion and Costume Design Association
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• v.8 no.3
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• pp.17-25
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• 2006

We performed the objective sensibility evaluation on knitted fabrics by the following procedures: setting acrylic fabrics with knitted fabrics as basis, knitted five kinds of blended spun yarns and four kinds of twisted filament yams made by different twisting methods(the amount and direction of twist) then, measuring mechanical properties in the use Kawabata Evaluation System, obtaining hand values and total hand values. The results are as follows: First, A(F)/W acrylic/wool spun knits obtain high scores in bending, compressing, shear properties, MMD, and thickness among five kinds of acrylic-blended knit fabrics. A(S)/W acrylic/wool blended knit represented prominent values at compressing properties and thickness and so wool-blended yams demonstrated superior characters comparing other blended yarns. To contrast, acrylic/rayon blended knits showed low scores in bending properties, shear properties and thickness, so that it affects to total hand values. On the one hand, among the four kinds of acrylic filament knitted fabrics, they do not exhibit any notable dynamic differences such as tensile properties of knitted fabrics by the twist number and direction of filament yarns, bending, shear, compressing properties, weight and thickness except surface properties. Second, fabrics showed the most high score at FUKURAMI (fullness and softness) among the hand values. A(S)/W acrylic/wool blended knits obtaining the lowest values at SAHRI (crispness) outrank at total hand values, so that it was the predominant knitted fabric in objective sensibility evaluation. In total hand values, five kinds of acrylic blended knits got a higher score than four kinds of acrylic filament knits, and the amount and direction of twist did not influence on total hand values among the four kinds of acrylic filaments.