• Title/Summary/Keyword: fatigue analysis

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A Study on the Strength Characteristics and Failure Detection of Single-lap Joints with I-fiber Stitching Method (I-fiber 스티칭 공법이 적용된 Single-lap Joint의 강도 특성 및 파손 신호 검출 연구)

  • Choi, Seong-Hyun;Song, Sang-Hoon;An, Woo-Jin;Choi, Jin-Ho
    • Composites Research
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    • v.34 no.5
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    • pp.317-322
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    • 2021
  • When a complex load such as torsion, low-speed impact, or fatigue load is applied, the properties in the thickness direction are weakened through microcracks inside the material due to the nature of the laminated composite material, and delamination occurs. To prevent the interlaminar delamination, various three-dimensional reinforcement methods such as Z-pinning and stitching, and structural health monitoring techniques that detect the microcrack of structures in real time have been continuously studied. In this paper, the single-lap joints with I-fiber stitching process were manufactured by a co-curing method and their strengths and failure detection capability were evaluated. AE and electric resistance method were used for detection of crack and failure signal and electric circuit for signal analysis was manufactured, and failure signal was analyzed during the tensile test of a single-lap joint. From the experiment, the strength of the single lap joint reinforced by I-fiber stitching process was improved by about 44.6% compared to the co-cured single lap joint without reinforcement. In addition, as the single-lap joint reinforced by I-fiber stitching process can detect failure in both the electrical resistance method and the AE method, it has been proven to be an effective structure for failure monitoring as well as strength improvement.

Review of Korean Medicine Treatments for Purpura and Vasculitis in Korean Journals (혈관염 및 자반증의 한의학적 치료에 대한 국내 임상 논문 분석)

  • Kang, Dong-Won;Park, Jung-Gun;Han, Chang-Yi;Kim, Kyu-Seok;Kim, Yoon-Bum
    • The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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    • v.32 no.3
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    • pp.116-135
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    • 2019
  • Objectives : The purpose of this study is to analyze how purpura and vasculitis have been treated with Korean medicine and potentially to present with future direction of research and treatment. Methods : We searched clinical studies from the Korean databases including Oriental medicine Advanced Searching Integrated System(OASIS), Korean Traditional Knowledge Portal(KTKP), National Discovery for Science Leader(NDSL), Research Information Sharing Service(RISS), using keywords related to "Purpura" and "Vasculitis" from January 2000 to May 2019. Results : A total of 20 studies were selected for analysis. More than half of the patients provided with detailed information were under 19 year-olds, and upper respiratory infection, stress and fatigue, seasonal factor were among the most frequently stated as predisposing factors. Among many treatment modalities, herbal medicine was the most frequently used, followed by acupuncture and herbal acupuncture. 23 basic herbal medicine formulas were retrieved from 20 articles, most frequently used being Guibi-tang(歸脾湯加味), Samul-tang(四物湯加味) and Yukmijihwang-tang(六味地黃湯加味). In total, 122 Korean medicine herbs were used, most frequently used herbs being Glycyrrhizae Radix et Rhizoma(甘草), Angelicae Gigantis Radix(當歸), Poria Sclerotium(茯?) and Paeoniae Radix(芍藥). By its category, herbs were mostly classified into Tonyfying and replenishing medicinal(補益藥), Heat-clearing medicinal(淸熱藥) and Exterior-releasing medicinal(解表藥). Patients with total treatment period of 3 months or under were 2/3 of all cases provided with detailed information. Follow up periods were short in general with only 6 cases of over 6 months. The primary motive of patients to receive Korean medicine treatments was unresponsiveness or adverse effects of western medication. Conclusion : Through this literature review, we could find out tendencies of Korean medicine treatments of purpura and vasculitis up to date and some points that may have clinical significance.

A Study on the Factors of Life Satisfaction of the Adults with Developmental Disabilities (그룹홈 중고령 발달장애인의 생활만족도 영향요인 연구: 청년기 발달장애인과의 비교를 중심으로)

  • Roh, Seung Hyun;Kim, Cheong Seok
    • 재활복지
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    • v.22 no.3
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    • pp.69-91
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    • 2018
  • This study aims to identify factors of life satisfaction of the adults with developmental disabilities, focusing on the comparison between young and old. Data are collected through in-depth interview of the adults with developmental disabilities as well as via workers proxy responses at the group home. Regression model analysis is conducted based on 387 cases. The result shows that the young adults with developmental disabilities are more likely to satisfied with life when they evaluate job performance of workers at the group home and when they are more actively involved in community activities. For the old adults with developmental disabilities, life satisfaction is positively associated with their evaluation of job performance of workers at the group home as in the young adults. In addition, life satisfaction of the old adults is higher when they feel less fatigue. It is also higher for those with more choices on residence and higher level of social activities. The findings reveals that enhancement of life satisfaction for the old adults with developmental disabilities dwelling at group home require supports and services for health and social activities different from other ages. It shares the general ideas that service efforts should be made for needs and desires of the recipients. The present study suggests to expand our research interests to include the disabled in danger of early aging, such as the persons with Down Syndrome and the persons with intellectual disability and cerebral palsy, and look into their particular needs.

Analysis on the Changes in Muscle Function of the Leg Joint in Athletics Athletes Through by Whole Body Vibration Exercise Training (전신진동(Whole body vibration)운동훈련을 통한 육상 투척선수의 하지관절 근육 기능변화에 관한 분석)

  • Lee, Youngsun;Yoon, Changsun;Han, KiHoon;Kim, Jinhyun;Hah, Chongku;Park, Joonsung;Kim, Jongbin
    • Journal of Convergence for Information Technology
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    • v.11 no.3
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    • pp.250-260
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    • 2021
  • The purpose of this study is to investigate muscle function and symmetry index during whole body vibration exercise using lower extremity training posture for throwing athletes. For throwing athletes in their 20s(6 males, 4 females, age: 24.60±0.92years, height: 177.90±7.40cm, weight: 92.90±22.97kg), lower extremity training postures with squat, carphrase, and lunge movements. Whole body vibration exercise training was performed using. Tensiomyography(TMG) variables Time Delay(Td), Time Contraction(Tc), Time Sustain(Ts) Time Relaxation(Tr), and Displacement Maximumal(Dm) in the lower extremity joint muscles(biceps femoris(BF), gastrocnemius lateral(GL), gastrocnemius medial(GM), rectus femoris(RF), tibialis anterior(TA), lateral vastus(LV), medial latissimus(ML)), were measured to compare and analyze muscle activity, muscle fatigue, and left-right symmetry. The results of the study are left RF, VL, right VM (p<.05) in Td, VM (p<.05) in Tc, GM in Ts (p<.05), left RF in Tr, and right TA (p<. 05) showed a change. Therefore, it has been proven that various whole-body vibration training is an effective exercise with changes in muscle contraction, and stability of the core is secured by symmetry of the left and right muscles. For this reason, the whole body vibration exercise will have a positive effect on rehabilitation training, and it is believed that it will be able to improve performance.

An Analysis of the Trends of Aromatherapy Researches in Chinese Literatures

  • Sun, Jiao-Jing;Kim, Kyeong-Ran
    • Journal of the Korea Society of Computer and Information
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    • v.26 no.1
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    • pp.239-251
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    • 2021
  • Traditional Chinese medicine has treated diseases and improved health in nature-based experience. Advanced nations began to be interested in naturopathic therapy in the late 19th century and it led China to research aromatherapy. This study searched previous researches related with aromatherapy and generally analyzed aroma oil, applied body parts, methods of use, and period of use. For research contents, scientific and society journals from 2000 to 2019 related with aromatherapy were searched in CNKI(www.cnki.com) and WANFANG DATE(www.wanfang.com). Finally, 30 papers were selected through 5-step qualitative evaluation and expert review and analyzed. Frequency and percentage(%) were calculated by means of the Excel 2013 Program and represented by a chart. The results of analyzing aromatherapy trends are as follows. All 30 papers were researched in the medical society. The most common symptom was irritation and anxiety that appeared in 13 papers. Lavender oil and bergamot oil were commonly used aroma oil. Commonly applied part and method were nose and nasal inhalation. For aroma oil associated with symptoms, lavender oil was the best in irritative, anxious, and negative emotion, depression, labor pain, sleep disorder, migraine, tension, and vomiting, pain, and fatigue after operation. Lemon, ginger, and peppermint oil was good for nausea. Based on the findings, this study derived applied body parts, methods of use, and period of use in aromatherapy. However, most aromatherapy was used for patients in the nursing and medical fields in the simple form of inhalation and local massage. This study will suggest a standard ground that aromatherapy is good for pain, colic pain, and tension in a short period but needs a long period for the efficacy of psychological and neurological symptoms.

Thickness Design of Composite Pavement for Heavy-Duty Roads Considering Cumulative Fatigue Damage in Roller-Compacted Concrete Base (롤러전압콘크리트 기층의 누적피로손상을 고려한 중하중 도로의 복합포장 두께 설계)

  • Kim, Kyoung Su;Kim, Young Kyu;Chhay, Lyhour;Lee, Seung Woo
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.42 no.4
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    • pp.537-548
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    • 2022
  • It is important to design the pavement thickness considering heavy-duty traffic loads, which can cause excessive stress and strain in the pavement. Port-rear roads and industrial roads have many problems due to early stress in pavement because these have a higher ratio of heavy loads than general roads such as national roads and expressways. Internationally, composite pavement has been widely applied in pavement designs in heavy-duty areas. Composite pavement is established as an economic pavement type that can increase the design life by nearly double compared to that of existing pavement while also decreasing maintenance and user costs. This study suggests a thickness design method for composite pavement using roller-compacted concrete as a base material to ensure long-term serviceability in heavy-duty areas such as port-rear roads and industrial roads. A three-dimensional finite element analysis was conducted to investigate the mechanical behavior and the long-term pavement performance ultimately to suggest a thickness design method that considers changes in the material properties of the roller-compacted concrete (RCC) base layer. In addition, this study presents a user-friendly catalog design method for RCC-base composite pavement considering the concept of linear damage accumulation for each container trailer depending on the season.

The Effect on Legibility of the Inner Space Width of Hangeul Characters: Focusing on the Outer Space Width (한글꼴의 속공간 넓이가 가독성에 미치는 영향: 외부 속공간을 중심으로)

  • Jeon, Eoun-Sun;Kim, Sung-Kye
    • The Journal of the Korea Contents Association
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    • v.22 no.7
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    • pp.498-510
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    • 2022
  • Among the various factors that form fonts, the concept of a new Korean font term called Inner Space Width was developed and the effect of changes in fonts applied to readability was analyzed. [Experiment 1] An empirical analysis was attempted on how the Korean-shaped Outer Space Width affects readability among the texts. Among the factors that make up the paragraph, Outer Space Width by letter size, letter size, letter spacing, letter spacing, and letter shape was composed of Yoon Myung-jo 110-160 and Inner Space Width of Yoon Myung-jo 110 was the widest at 26.83%. [Experiment 2] In-depth interviews with experts were conducted to derive factors and evaluation indicators constituting the inner space. Inner Space Width is evaluated as a complex factor that affects preference and fatigue, and is related to understanding and speed. This study empirically reviewed the effect on readability using the concept of Inner Space Width in the absence of existing research on Hangul-shaped fast space, and is expected to be actively used in the development of fonts in the future.

Well-being Tourism and Wellness Mediated Effects to Improve Quality of LifeFocusing on Forest Healing Program Users (삶의 질 향상을 위한 웰빙관광과 웰니스의 매개효과: 숲치유프로그램 이용자를 중심으로)

  • Lee, Woong-Bae
    • The Journal of the Korea Contents Association
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    • v.21 no.12
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    • pp.264-274
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    • 2021
  • This study aims to analyze the impact of well-being tourism motivation on quality of life through well-being tourism satisfaction, focusing on wellness mediated effects. Recently, despite the growing number of well-being tourism pursuing wellness, the lack of research has led to a close analysis of the impact of well-being tourism motivation on quality of life through well-being tourism satisfaction. For this study, a total of 236 people who have experienced well-being tours in the metropolitan area were surveyed from May 10 to May 21, 2021. First, well-being tourism motivation has a positive effect on well-being tourism satisfaction. Second, well-being tourism satisfaction has a positive impact on the quality of life. Third, Wellness has a positive indirect effect as a partial mediator between well-being tourism satisfaction and quality of life The implications of this study are to demonstrate the impact of well-being tourism on quality of life using Wellness' mediators This study suggests that wellness tourism plays an important role in improving the quality of life. It was analyzed that well-being tourism had a positive effect on improving the quality of life at a time when the fatigue of daily life was increased due to prolonged COVID-19. In addition, Wellis analyzed that it is an important factor in enhancing the quality of life for well-being tourists. This contributes not only to the academic contribution to the revitalization of well-being tourism, but also to the development of stress improvement routes to improve people's lives nationally.

The Effect on Attention of College Students by Epidermal Cooling in Posterior and Lateral of Upper Cervix (경추부 후면 및 측면 피부 냉각 작용이 대학생의 주의력에 미치는 영향)

  • Chang, Ji Hong
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.15 no.5
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    • pp.328-334
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    • 2022
  • The process that one may consciously focuses on necessary stimulation among tremendous amount of stimulation through human sensory systems is called attention in psychology. It is known that the attention can be affected by many factors such as room temperatures, humidity level, etc. In the field of sports science, ice packs are widely used for recovery from exercise fatigue providing fast heat transfer by conduction. However, the effect on attention by so-called iced-pack-cooling has not been tested. This research focuses on the attention levels when one is provided with a special cooling pad on their dorsal and lateral cervices. 40 subjects were divided into four groups and their attention level was evaluated based on the exposure conditions of combinations in reading and light walking with and without the cooling pad. The Frankfruter Aufmerksamkeits-Inventar, FAIR was used to evaluate the attention levels; the performance index, quality index, and continuity index consist of the FAIR test indicating the selectiveness of the attention, correctness of the attention, and maintaining term of the attention, respectively. Analysis of variance was carried out for those variables and post-hoc if applicable. When visual attention is constantly used for reading and studying, application of conductive heat transfer by the cooling pads is significantly helpful for improvement in selectiveness of the attention and maintaining terms of the attention levels. Also, light walking yielded improvement in selectiveness of the attention and maintaining terms of the attention levels; however one should presupposedly consider the loss of reading time.

The Effects of Teaching Reality and Learning Reality Perceived by College Students on Learning Satisfaction in Non-face-to-face Classes (비대면 수업에서 대학생이 인지하는 교수실재감과 학습실재감이 학습만족도에 미치는 영향)

  • Bak, Kyeong-Won
    • The Journal of the Korea Contents Association
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    • v.21 no.12
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    • pp.175-181
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    • 2021
  • The purpose of this study is to improve and develop the quality of non-face-to-face classes according to the types of presence by analyzing the effects of teaching presence and learning presence on the learning satisfaction of the non-face-to-face classes that have been suddenly conducted due to COVID-19. For this purpose, a survey on online classes of H University in Gwangju Metropolitan City was conducted to analyze learning satisfaction, teaching presence (learning design, direct promotion), and learning presence (cognitive presence, social presence). The results of the analysis showed that the learning contents of cognitive presence, which is a sub-factor of learning presence, were understood (=.589, p<.001), the direct promotion (=.420, p<.001), and the learning design (=.397, p<.01), which are the sub-factors of teaching presence, were influential in order.This means that the suddenly changed teaching method should have an attitude to improve the intimacy between the instructor and the fellow learners with positive emotional exchange or interaction. The instructor should try to overcome the limitations of time and space through blended learning that is both online and offline for high quality learning design, but the learning medium and learning method considering the physical fatigue of the learner should be developed.