• Composites Research
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• v.36 no.6
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• pp.448-453
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• 2023

This paper explores developing sustainable 3D printing filaments using organic soybean hulls mixed with polylactic acid (PLA). The study experiments with various particle sizes and mixing ratios, examining the physical and mechanical properties of the resulting filaments. Results show that smaller soybean hull particles and specific mixing ratios enhance the filament's quality while maintaining PLA's characteristics. This research signifies a step towards environmentally friendly 3D printing materials, offering a viable alternative to conventional filaments and addressing ecological concerns in the industry.

• Journal of Industrial Convergence
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• v.18 no.5
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• pp.108-117
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• 2020

This study aims to provide basic data for maintaining and promoting health of obese middle-aged women who are interested in various chronic diseases such as cardiovascular disease and coronary artery disease by comparing and analyzing the effect on body composition and lipid metabolism through a 12-week Pilates mat exercise program for obese middle-aged women. This study targeted middle-aged women residing in Gyeonggi-do A, who are obese middle-aged women in their 40s and 50s with a body fat ratio of 30% or more, and had no regular exercise in the past three months. Obese middle-aged women(n=19) were divided into two groups, the Pilates mat exercise program group(n=9) and the control group(n=10), conducting exercise for 60 minutes three times a week for 12 weeks. As a result of analysis, the exercise group had a positive effect on body weight, skeletal muscle mass, body fat mass, body fat percentage, and BMI in body composition, but not in the control group. In the lipid metabolism, the exercise group had a positive effect on TC, TG, HDL-C, LDL-C, and FFA, but not in the control group. These results suggest that the 12-week Pilates mat exercise program conducted in this study is an exercise program that can prevent cardiovascular and chronic diseases in obese middle-aged women.

• Journal of the Korean Applied Science and Technology
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• v.37 no.4
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• pp.878-892
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• 2020

The purpose of this study is to explore the effects of pregnant women's taking of probiotics and pilates exercise on Postnatal women's body composition, gut-microbiota, obesity hormones, blood lipid, inflammatory cytokine. Overall clinical trial procedures are as follows. First, a total of 15 pregnant women were classified into 3 groups, probiotics intake+exercise group(PEX, n=5), exercise group(EX, n=5), and control group(CON, n=5). The PEX and EX groups participated in the pilates exercise twice a week for eight weeks, with 10 min for warm-up, 30 min for main exercise and 10 min for cool-dawn. The probiotics had to take one capsule a day on its empty stomach every day. The results showed that intestinal harmful bacteria were inhibited after childbirth in PEX group, and body fat, WHR reduction. There were also positive effects on the decrease of leptin hormone in PEX group and on IL-6, TNF-a levels. The caesarean section ratio of CON group compared to PEX and EX group was found to be high. Conclusion pregnant women's probiotics intake and pilates exercise will be effective in women's abdominal fat reduction after childbirth, and will have positive effects on inflammatory levels and appetite control hormones, which will be effective in preventing and treating obesity for after childbirth.

• Journal of Convergence for Information Technology
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• v.11 no.12
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• pp.254-264
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• 2021

This study was conducted to investigate changes in posture and muscle characteristics by applying mat pilates and kinesio taping to college students with round shoulder posture and to investigate effective interventions. Subjects were 28 men and women with a round shoulder posture, and they were randomly assigned to a mat pilates group (MPG, n=14) and a Kinesio taping group (KTG, n=14). Each group performed the intervention for 4 weeks, and the distance from the ground to the acromion(DGA) and muscle characteristics (F: Frequency; S: Stiffness; D: Decrement) were measured before and after the intervention. Independent T-test was performed for the difference in the amount of change between groups, and the paired-sample T-test was performed for the difference between pre-post values within the group. Statistical significance level was set as 𝛼=.05. As a result of measuring the change in DGA in both groups, it was significantly decreased in MPG (p<.05). As a result of measuring the change in muscle characteristics of the two groups, the change in F in TL was significantly increased in MPG (p<.05), there was no change in TG, and the amount of change in MPG was larger in the amount of change between the two groups. appeared (p<.05). The change in S was significantly increased in MPG (p<.05). Therefore, the mat pilates conducted in this study is considered to be an effective intervention for improving the round shoulder posture and changing the muscle characteristics than kinesio taping.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.7
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• pp.430-439
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• 2019

In this study, a nonlinear impact analysis was performed to evaluate the safety and damage of an eco-pillar debris barrier with a hollow cross-section, which was proposed to improve constructability and economic efficiency. The construction of concrete eco-pillar debris barriers has increased recently. However, there are no design standards concerning debris barriers in Korea, and it is difficult to find a study on performance evaluations in extreme environments. Thus, an analysis of an eco-pillar debris barrier was done using the rock impact speed, which was estimated from the debris flow velocity. The diameters of rocks were determined by ETAG 27. The impact position, angles, and rock diameter were considered as variables. A concrete nonlinear material model was applied, and the estimation of damage was done by ABAQUS software. As a result, the damage ratio was found to be less than 1.0 at rock diameters of 0.3 m and 0.5 m, but it was 1.39 when the diameter was 0.7 m. This study could be used as basic data on impact force in the design of the cross section of an eco-pillar debris barrier.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.5
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• pp.823-837
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• 2018

Congestion of the city with the rapid industrial development was accelerated to build complex social infrastructure. And numerous structures have been designed and constructed in accordance with these requirements. Recently, to solve complex urban traffic, many researches of large-diameter tunnel under construction downtown are in progress. The large-diameter tunnel has been developed with a versatile double-deck of deep depth tunnel. For the safe tunnel construction, ground reinforcement methods have been developed in the weakened pillar section like as junction of tunnel. This paper focuses on evaluation of the effects of new developed ground reinforcement methods in double-deck junction. The values of reinforcement determined from the existing and developed methods were compared to each other by numerical simulation.

• Journal of the Korean Society of Radiology
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• v.15 no.5
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• pp.697-704
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• 2021

It is hard to get Filaments which are materials of the 3D printing Fused Deposition Modeling(FDM) method as radiation shielding in Korea. and also related research is insufficient. This study aims to provide basic data for the development of radiation shields using 3D printing by evaluating the physical properties and radiation shielding capabilities of filaments containing metal particles. after selecting five metal filaments containing metal particle reinforcement materials, the radiation shielding rate was calculated according to the Korean Industrial Standard's protective equipment test method to evaluate physical properties such as tensile strength, density, X-ray Diffraction(XRD), and weight measurement using ASTM's evaluation method. In the tensile strength evaluation, PLA + SS was the highest, ABS + W was the lowest, and ABS + W is 3.13 g/cm³ which value was the highest among the composite filaments in the density evaluation. As a result of the XRD, it may be confirmed that the XRD peak pattern of the particles on the surface of the specimen coincides with the pattern of each particle reinforcing material powder metal, and thus it was confirmed that the printed specimen contained powder metal. The shielding effect for each 3D printed composite filament was found to have a high shielding rate in proportion to the effective atomic number and density in the order of ABS + W, ABS + Bi, PLA+SS, PLA + Cu, and PLA + Al. In this study, it was confirmed that the metal particle composite filament containing metal powder as a reinforcing material has radiation shielding ability, and the possibility of using a radiation shielding filament in the future.

• Journal of Korean Society of Steel Construction
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• v.23 no.4
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• pp.429-438
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• 2011

In this study, the explicit numerical algorithm was proposed to simulate the stress erection process and ultimate-load analysis of the strarch (stressed arch) system. The strarch system is a unique and innovative structural system and member prestress comprising prefabricated plane truss frames erected through a post-tensioning stress erection procedure. The flexible bottom chord, which has sleeve and gap details, is closed by the reaction force of the prestressing tendon. The prestress imposed on the tendon will enable the strarch system to be erected. This post-tensioning process is called "stress erection process." During this process, plastic rigid-body rotation occurs to the flexible top chord due to the excessive amount of plastic strain, and the structural characteristic is unstable. In this study, the dynamic relaxation method (DRM) was adopted to calculate the nonlinear equilibrium equation of the system, and a displacement-based finite-element-formulated filament beam element was used to simulate the nonlinear behavior of the top chord sections of the strarch system. The section of the filament beam element was composed by the amount of filaments, which can be modeled by various material models. The Ramberg-Osgood and bilinear kinematic elastic plastic material models were formulated for the nonlinear material behaviors of the filaments. The numerical results that were obtained in the present study were compared with the experiment results of the stress erection and with the results of the ultimate-load analysis of the strarch unit frame. The results of the present studies are in good agreement with the previous experiment results, and the explicit DRM enabled the analysis of the post-buckling behaviors of the strarch unit frame.

• Journal of the Korean Applied Science and Technology
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• v.40 no.1
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• pp.95-102
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• 2023

The purpose of this study is to figure out the effect of 12 weeks pilates program for body shape improvement and lumbar stabilization of senior women with chronic back pain and to provide data for developing excercise program which is appropriate for senior women to make aging delayed and to have more physical activity domain by inquiring into their pain reducing. The subjects of this study were 16 senior women with chronic back pain which were classified into two group with experimental group(n=8) and control group(n=8) by applying simple random sampling after conducting Visual Analogue Scale(VAS). Their motion range of pain was from 3 centimeters to 5 centimeters. Pilates excercise for lumbar stabilization in this study was originated the previous literature of Lee et al(2011) and the excercise was modified in the form of pilates. The program in the study was performed under the guidance of a professional pilates trainer. The results are as follows. Firstly, the experimental group showed positive improvement in making vertebra slope but the control group showed pain increased. Secondly, the lumbar pain decreased in the experimental group but it increased in the control group. As a result, the pilates program for lumbar stabilization can be considered as a program for pain relief and body shape improvement of senior women with chronic back pain.

• Journal of the Korean Applied Science and Technology
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• v.35 no.3
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• pp.905-913
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• 2018

The purpose of this study is to investigate the difference of muscle activity according to application of a foam roller during pilates. The 8 male subjects were selected and quadruped position, bridge, and core control movement of pilates were randomly assigned to 9 movements on a static mat motion, static foam-roller motion, and dynamic foam-roller actions. This program was conducted once at intervals of 1 week. The muscle activity of erector spinae, rectus abdominis, external oblique, gluteus medius, rectus femoris, and biceps femoris were measured and the collected data was analyzed by one-way ANOVA. First, in the quadruped, the rectus abdominis and external oblique, rectus femoris of the dynamic foam-roller actions showed higher muscle activity than the static mat motion and the static foam-roller motion(p <.001), gluteus medius muscle activity was also significantly higher (p <.05). biceps femoris were significantly higher in static foam-roller motions than in static mat-motion and dynamic foam-roller actions(p <.05). Second, biceps femoris muscle activity was highest in dynamic foam-roller actions than static mat-motion and static foam-roller motions during bridge(p <.001). Third, in the sitting core control, the rectus abdominis and gluteus medius of the dynamic foam-roller actions showed higher muscle activity than the static mat motion and the static foam-roller motion(p <.001). and activity of erector spinae muscle was also significantly higher (p <.01). external oblique were significantly higher in static mat-motion than in static foam-roller motions and dynamic foam-roller actions(p <.05). Considering the muscle activity during pilates exercise, it would be more effective to apply the method and difficulty.