• Journal of the Korea Fashion and Costume Design Association
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• v.20 no.4
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• pp.73-82
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• 2018

This research investigated the mechanical properties of the 4 different types of $3{\times}3$ cable stitches on weft knitted fabrics. The 4 kinds of cable-stitch fabrics were knitted under the same knitting conditions, then the mechanical properties, such as tensile strength, elongation, stiffness, etc. were measured according to the Korean Industrial Standards (KS K 0642). The knitting time for the sample produced by the knitting process 1 was the shortest among the 4 different types of samples. It means that the knitting process 1 would have benefits of higher productivity if there is no yarn breakage during the knitting of the cable stitches. In the test for tensile strength, the samples produced by knitting processes 3 and 4 have tensile values of approximately 8~11% higher than the sample produced by knitting process 1. The test for elongation also shows that the samples produced by knitting processes 3 and 4 have up to 18% higher elongation values than the sample produced by knitting process 1. On the other hand, the stiffness test showed no significant difference between the 4 samples. This study is expected to increase the competitiveness of the local knitting industry as a result of providing basic data on the mechanical properties of special knitted stitches, such as cable stitches.

• Physical Therapy Rehabilitation Science
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• v.11 no.4
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• pp.446-453
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• 2022

Objective: The popularization of smartphones can lead to abnormal cervical alignment in university students. The aim of this study was to investigate the relationship among smartphone screen time, cervical alignment, and muscle function in university students. Design: Cross-sectional study. Methods: Seventy-five university students participated in the study. They completed the evaluation of cervical alignment and muscle function, such as handgrip strength, proprioception, and muscle quality (tone, stiffness, and relaxation time). All participants recorded their general characteristics and individual smartphone screen time before the evaluation. They were evaluated craniovertebral angle (CVA) using smartphone application (angle meter 360) for measuring cervical alignment. The muscle function was assessed using a digital hand-held dynamometer, dual inclinometer, and MyotonPRO device. Results: Of all participants, twenty-five university students had forward head posture (CVA<49°, 33.33%). Independent t-test revealed that there were significant differences on smartphone screen time, muscle stiffness, and muscle relaxation between the participants with and without forward head posture (p<0.05). There were significant correlations between the smartphone screen time and the CVA, muscle tone, and muscle relaxation (r=-0.493, 0.250, and -0.500, respectively). Conclusions: The results indicate that the university students with forward head posture had high smartphone screen time and muscle stiffness compared to the students without forward head posture, and smartphone screen time might be associated with cervical alignment and muscle quality.

• Journal of the Korean Society of Clothing and Textiles
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• v.23 no.8
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• pp.1194-1205
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• 1999

The hand characteristics of bast blended fabrics are studied by a subective evaluation method. To offer basic data for development of better hand of bast fiber fabrics customer's hand preference surveys are executed as well. IN this study 51 varieties of linen or ramie blended fabrics of various blending ratio density and thickness and Hansan ramie Chinese ramie and a Shingosen fabics of various blending ratio density and thickness and Hansan ramie Chinese ramie and a Shingosen farbic and used. To evaluate the hand of the fabrics subjectively nine ranks' semantic differential scale questions of 26 items are developed with adjective pairs. A seven ranks' scale is also developed to evaluate hand preferences in blouse and jacket cloths, Through subjective evaluation of bast blended fabrics the 26 items could be classified into seven kinds of hand classification : surface characteristics extensibility/drapability felling of heaviness stiffness resilience moisture property and feeling of density. The cumulative variance value explained by these seven factors is 67.18% According to the results of fabrics' preference by age groups no significant differences are found in blouse cloths but a few significant differences are found among different age groups in jacket clothes. However experts and non-experts show considerable differences on preference It can be concluded that fabrics' preference I more dependent on professionality than on age. In the survey experts. However more drapery cloths are preferred by experts and cloths with drier touch are preferred by non-experts. Experts prefer rougher less even less winding heavier and sparser fabrics but non-experts prefer rougher lighter thinner and stiffer fabrics as jacket cloths.

• Journal of the Korea Fashion and Costume Design Association
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• v.10 no.2
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• pp.125-138
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• 2008

For physical and hand property evaluation of fabrics, the knitted fabrics from 11 types of machines knitting fancy yarns, boucle (M1), knot (M2), snarl (M3), and slub (M4), tamtam (M5), tubular (M6), fur 1 (M7), bead (M8), fur 2 (M9), fur 3 (M10), and ladder (M11) yarns, were prepared with 7-10 G plain stitch. Washing test and pilling test had also been carried out. For hand properties by objective sensibility evaluation, 17 items of sir mechanical properties using KES-FB (Kawabata Evaluation System) had been measured. Then hand values of knitted fabrics were calculated with a calculation formula, namely KN-402-KT. Finally the total hand values were obtained through KN-301-WINTER. As a result of physical properties and objective evaluation for machines knitting fancy fabrics, most of them shrank in the direction of wale and course after the washing test, in which their shrinkage rate had a maximum of 3.5%. Therefore, the washing test indicated that the shrinkage ratio of knitted fabrics had a minor change. The results of the pilling test are mostly 4-5th grade, and all of the machines knitting fancy fabrics showed good results in the pilling resistance. In hand properties and objective sensibility evaluation, twisted fancy yarns, such as boucle (M1), knot (M2), snarl (M3), and slub (M4), were superior to bonding rigidity (B) and shear rigidity (G). The surface property between course and wale differs in all samples and course direction is tougher than wale direction. FUKURAMI (fullness and softness) of all samples have high values, besides NUMERI (smoothness) of tamtam (M5) and boucle (M1), which were rather good. Most samples except fur 1 (M7) had low KOSHI (stiffness) value. The total hand value (THV) of twisted yarns was low. This study proves that manufacturers, who plan knitting yarn products and knit fashion, can apply these data to develop machines knitting yarns and knits that fit the consumers' demands.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.26 no.1
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• pp.30-35
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• 2017

The major parts of a vacuum cleaner are molded. The vacuum cleaner works in multi-load conditions. Therefore, the designer needs to optimize the structure and injection molding conditions simultaneously. Here, the main factor of design is the rib shape and thickness. The greater the rib thickness, the greater the stiffness of the structure. However, it causes an increase in weight. On the other hand, the lower the rib thickness, the greater the increase in the injection pressure. However, the weight will be reduced. Therefore, the designer needs to optimize the rib shape and thickness for structure stiffness and injection molding. In order to solve this problem, we propose an optimization method using D.O.E and a response surface model, which is a multi-objective optimization method using the multi-objective genetic algorithm.

• Computers and Concrete
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• v.13 no.3
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• pp.377-387
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• 2014

This paper presents an experimental study on socket base connections of precast reinforced concrete columns. The main purpose of this study is to determine socket base connection which has the closest behavior to monolithic casted column-base joints. For this purpose, six specimens having different column-socket base connection details were tested under cyclic loading. For each test, strength, stiffness, ductility and drift ratios of the specimens were determined. Test results indicated that a suggested connection type is 10%-30% stronger than the other type of connections under lateral loading. The welded connection (PC-5) had better lateral load carrying capacity and ductility. On the other hand, performance of standard connection (PC-1) which is commonly used in construction was weaker than other connections. Thus, decision of connection type should be referred not only performance but also applicability.

• The Korean Journal of Pain
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• v.11 no.1
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• pp.138-142
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• 1998

Fibromyalgia syndrome is defined as a diffuse, aching musculoskeletal pain associated with multiple and discrete predictable tender points along with stiffness. A primary form associated without any disease is uncommon compared to the secondary diffuse fibrositis. We witnessed a case of a primary fibromyalgia syndrome. A 28-year-old woman was suffering from pain on posterior neck, right shoulder, upper back, left hand and arm for two years. She also complained of morning stiffness, fatigue, and headache. We treated her with stellate ganglion block with 0.25% bupivacaine, medication that included amitriptyline, TENS and superlizer. We also recommended aerobic exercise.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.84-87
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• 1999

This paper proposes an interfaces control system to drive a ultrasonic motors(USMs). To touch surfaces and objects created within a virtua environment, the 3 DOF force-reflecting interfaces provides force feedback to users, so to feel touching real things. To effectively display the mechanical impedance of the human hand we need a device with specific characteristics, such as low inertia almost zero friction and very high stiffness. As an actuator for direct drive method, the USMs have many good advantages satisfied these conditions over conventional servo motors. To estimate capability of this interface, we did an experiment. The device works very well, as user are able to detect the edge of the wall and the stiffness of the button.

• Transactions of the Society of Information Storage Systems
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• v.8 no.1
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• pp.33-38
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• 2012

To investigate of load/unload performance, FE (finite element) model of conventional suspension and HAMR suspension were made. The FE models were verified by modal analysis. In the loading simulation, the conventional system could stably load onto the disk without contact. On the other hand, the HAMR suspension which had an optical fiber and prism occurred slider - disk contact. In the unloading process, the conventional system was unloaded without contact. However, in the HAMR suspension, the contact between slider and disk was occurred at the moment that the dimple was separated during unload process. Therefore the load/unload performance of HAMR decrease with high stiffness, it is necessary that stiffness of HAMR suspension should reduced with design parameters of optical fiber and prism.

• The Journal of Korea Robotics Society
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• v.17 no.3
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• pp.347-352
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• 2022

The paper presents how to update impedance control parameters for dual-arm manipulators using EMG signals and motions of the operator. Since the hand motions of the dual-arm are modeled to be the mass-spring-damper system in this paper, the impedance parameter update method is an important issue to reflect the operator's force. However, task space inertia to be used as the mass parameter goes to infinity if the manipulator approaches a kinematic singularity. To alleviate this issue, the impedance (stiffness and damping) parameters are divided with a diagonal element of the task space inertia. Also, the stiffness and damping matrices are updated using the normalized EMG signals captured from the operator's forearm. Through this process, the motion of the dual-arm manipulator is more stabilized even though it approaches the kinematic singularity.