• Title/Summary/Keyword: fatigue response

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ML-based prediction method for estimating vortex-induced vibration amplitude of steel tubes in tubular transmission towers

  • Jiahong Li;Tao Wang;Zhengliang Li
    • Structural Engineering and Mechanics
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    • v.90 no.1
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    • pp.27-40
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    • 2024
  • The prediction of VIV amplitude is essential for the design and fatigue life estimation of steel tubes in tubular transmission towers. Limited to costly and time-consuming traditional experimental and computational fluid dynamics (CFD) methods, a machine learning (ML)-based method is proposed to efficiently predict the VIV amplitude of steel tubes in transmission towers. Firstly, by introducing the first-order mode shape to the two-dimensional CFD method, a simplified response analysis method (SRAM) is presented to calculate the VIV amplitude of steel tubes in transmission towers, which enables to build a dataset for training ML models. Then, by taking mass ratio M*, damping ratio ξ, and reduced velocity U* as the input variables, a Kriging-based prediction method (KPM) is further proposed to estimate the VIV amplitude of steel tubes in transmission towers by combining the SRAM with the Kriging-based ML model. Finally, the feasibility and effectiveness of the proposed methods are demonstrated by using three full-scale steel tubes with C-shaped, Cross-shaped, and Flange-plate joints, respectively. The results show that the SRAM can reasonably calculate the VIV amplitude, in which the relative errors of VIV maximum amplitude in three examples are less than 6%. Meanwhile, the KPM can well predict the VIV amplitude of steel tubes in transmission towers within the studied range of M*, ξ and U*. Particularly, the KPM presents an excellent capability in estimating the VIV maximum amplitude by using the reduced damping parameter SG.

The clinical manifestation of migraine and correlation study with autonomic bioelectric response (편두통 환자의 임상 양상 및 생체전기 자율반응과의 상관성 고찰)

  • Lee, Hyun-jong;Jung, In-tae;Kim, Su-young;Lee, Doo-ik;Kim, Keon-sik;Lee, Jae-dong;Lee, Yun-ho;Choi, Do-young
    • Journal of Acupuncture Research
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    • v.21 no.3
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    • pp.215-229
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    • 2004
  • Objective : We had a clinical report in headache but didn't in migraine. We have planned this study in order to get the basic data of migraine in oriental medicine. Methods : The patient of 36 in migraine checked sex, age, onset, family history, severity of pain, influences of life, induced cause, clinical pain characteristics, associated symptom, treatment style, and prescription, frequency, using period of analgesics by a questionnaire and differentiated syndromes in migraine and evaluated autonomic bioelectric response recorder(ABR-2000). Results : There are 23.4% in prevalence rate of migraine. The ratio of sex is M:F=1:17. The age of an attack is the highest in thirties. The patient are the most in forties. The mean duration of illness is $12.0{\pm}9.9$ years. 83.4% had a family history. 61.1% had a moderate grade in severity of pain. 77.8% selected fatigue in induced cause of migraine. 69.4% had tingling sense, nausea and vomiting in the associated symptoms. 91.7% used analgesics for treatment and 51.5% of them used analgesics voluntarily. 61.9% of them take analgesics less than once in a week. 33.6% had the phlegm syncope headache in differentiation of syndrome. In ABR-2000 results, item of graph showed low tendency mostly. Conclusions : We expected that this report of clinical progress, differentiation of syndromes and ABR-2000 results in migraine would be used basic data by oriental medicine to treat migraine.

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A Study on The Clinical Characteristics and Treatment in Burning Mouth Syndrome (구강 작엽감 증후군 (BMS)의 임상적 특징 및 치료에 관한 연구)

  • Mi-Jung Yeom;Chong-Youl Kim
    • Journal of Oral Medicine and Pain
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    • v.20 no.1
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    • pp.39-52
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    • 1995
  • Burning mouth syndrome is characterized by a burning sensation in oral cavity without clinical signs. There has b een no established theories about the diagnosis and treatment. The purpose of this article is to examine the clinical feature of BMS patients of Korean and to present a treatment protocol that can be helpful in clinical applications. The subjects chosen for the study were 52 patients who had visited Department of Oral Diagnosis at Yonsei University Dental Hospital and were diagnosed as BMS. We did questionnaires and precise oral exam, laboratory exam, grouping of our patients, individual treatment for the groups and classification of responses to the treatment. The following results were obtained: 1. Chief complaints were throbbing (71.2%), pricking, stinging, tingling (30.8%), burning(25a%). The tongue is the most frequently affected site (82.7%), followed by full mouth, gingiva, palate, buccal mucosa, lips, throat, labial mucosa and floor of mouth. 2. The average age of onset was 48.1 year and the male to female ratio was 1 to 3. The average duration of symptom was 11.69 months for male and 23.07 months for female. 3. 32.7% of patients had appealed continuous pain, which was the most cases. Aggravating factors were peppery food, salty food, hot food, fatigue, tension conversation, sour food, cold food and toothpaste. Reducing factors were cold food, diet, going to sleep and smoking. 4. Associated symptoms were dry mouth, other life problem, altered taste perception, bad taste, throat pain, tingle and difficulty in swallowing. 5. Most of patients had appealed that there was not associated event on onset of symptom, and the order of prevalence is as fallow; dental treatment, stress, denture wearing, an attack of a systemic disease. 92.3% of patient appealed that there was no psychological withering and 7.7% of patients appealed positively. 6. There were eight males and four females that had jobs. 7. There was no family history in 100% of patients in questions about presence of family history. 8. 96.2% of patients appealed that there was no oral habits. 13.5% of patients had dryness of oral mucosa in oral exam. A significant relation to dental prosthesis was not observable, but incidence of diseases due to stress appeared high in BMS which had the clinical characteristics as above. A group having low serum iron was 63.5% and in this group period of potential iron deficiency appeared high in incidence just before move to anemia. A group represented positive response was 38.5% in fungus study for Candida albicans. Since we can expect high treatment response by prescription of iron-contained drug and antifungal drug in these patients, diagnosing patients' condition of BMS can be achieved in more various aspects through study for serum iron and Candida albicans. Furthermore, it is expected that treatment protocol can be made.

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Development of Long-Life Asphalt Pavements Method Using High Modulus Asphalt Mixes (고강성 기층재를 적용한 장수명 아스팔트포장 공법 개발)

  • Lee Jung-Hun;Lee Hyun-Jong
    • International Journal of Highway Engineering
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    • v.8 no.3 s.29
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    • pp.49-61
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    • 2006
  • This study suggests long-life asphalt pavement method which can save maintenance cost by increasing the design and performance period of pavements. The high modulus asphalt binder developed and then various physical tests are performed. Laboratory performance tests and accelerated pavement test are conducted for the high modulus and conventional mixtures. The test results show that dynamic modulus values of high modulus mixtures are higher than those of the conventional mixtures, The high modulus mixtures yield better fatigue, rutting and moisture damage performance than conventional mixtures. Structural analysis is performed and a database is built up for long life asphalt pavement design. Pavement response model is developed through a multiple regression analysis program, SPSS using the database. A design software for the long life pavements is developed based on the pavement response model and laboratory and field performance tests results. In addition, optimum pavement sections and materials are suggested. The suggested AC thickness of long life asphalt pavement is 29cm. A Life cycle cost analysis(LCCA) is conducted to check the economical efficiency of the long life pavement section. The LCCA result shows that initial construction costs of long life and conventional pavements are almost equal, but long life pavement is more profitable in terms of the LCCA.

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A Study on Narrative Response to the Lack of Family in the Chinese Contemporary Growth Novel After the 1990s (1990년대 이후 중국 당대 성장소설에 나타난 가족결핍과 그 서사적 대응방식)

  • Kim, Bong-yeon
    • Cross-Cultural Studies
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    • v.47
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    • pp.1-26
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    • 2017
  • This paper focuses on three novels that reflect absence of family. Conflicts caused by absence of parents or lack of function and role of parents were principle drivers fueling growth novels. In Chinese growth novels, children in a long-standing tradition of emulsion and political pressure were unable to express their conflict with parents. Out of the collective interest and only until the late 1980s, which can be found of the individuals were able to fully appreciate the growth of children. Since the late 1990s, the creative individual cases to the growth is an important point of Chinese growth. Due to a close relationship of the literature and politics further noteworthy that the growth of state for personal growth for China's growth. Reform and opening up the end of the Cultural Revolution, the emergence of new generation of cultural sensitivity with a relatively free personal attention to the growth of the chance that can be. In this paper, created since the 1990s, the growth of the stories of yuhua (余華)'s "Cry in the Rain"("在細雨中呼喊"), sutong(蘇童)'s "The Northern Part of the City"("城北地帶"), wanggang(王剛)'s "English"("英格力士"), going to go through by focusing on how to respond in the lack of family. "Cry in the Rain" shows that a consciousness orphan child abandoned main actors 'consciousness from his birth parents and adoptive parents. "The Northern Part of the City" chronicles different growth stories of children who experienced a void because of their absent families and found comfort in peer groups. "English" is distinguished from the mainstream narrative of Chinese growth in terms of creating a role model. Individual growth through the role model in that it will eventually establish their own identities and further growth. Because of that, this novel is considered best practices of Chinese growth novels. This kind of narrative, which returns to the memory of the growth of growth, has a richer connotation amid various attempts by writers out of the past era of obsession and fatigue.

Experimental Study on Reducing Motion of Circular Cylinder in Currents (조류 중 원형실린더 형상 구조물의 거동감소를 위한 실험적 연구)

  • Lim, Jae Hwan;Jo, Hyo Jae;Hwang, Jae Hyuk;Kim, Jae Heui;Lee, Tae Kyung;Choi, Yoon Woo;Lee, Min Jun;Kim, Young Kyu
    • Journal of Ocean Engineering and Technology
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    • v.33 no.4
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    • pp.350-357
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    • 2019
  • The development of marine technology is expected to increase the demand for marine plants because of increasing oil prices. Therefore, there is also expected to be an increase in the demand for cylindrical structures such as URF (umbilical, riser, flowline) structures and spars, which are used operating in various seas. However, a cylindrical structure experiences vortex induced motion (VIM) in a current. In particular, for risers and umbilicals, it is important to identify the characteristics of the VIM because interference between structures can occur. In addition, various studies have been conducted to reduce VIM because it is the cause of fatigue damage to structures. The helical strake, which was developed for VIM reduction, has an excellent VIM reduction performance, but is difficult to install on structures and has a negative effect on heave motion. Therefore, the purpose of this study was to supplement the shortcomings of the helical strake and develop a high-performance reduction device. In the reduction device developed in this study, a string is placed around the structure inside the flow, causing vibration. The vibration of this string causes a small turbulence in the flow field, reducing the VIM effect on the structure. Finally, in this study, the 2-DOF motion characteristics of models without a suppression device, models with a helical strake, and models with a string were investigated, and their reduction performances were compared through model tests.

Study on Effect of Varience of Physiological Responses in Color Foot Reflexology Using Color Light (컬러광을 활용한 발반사요법이 인체 생리적 반응 변화에 미치는 영향에 관한 연구)

  • Jin, Hye-Ryeon;Yu, Mi;Park, Kyung-Jun;Kim, Nam-Gyun;Chung, Sung-Whan;Kim, Dong-Wook
    • Science of Emotion and Sensibility
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    • v.13 no.1
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    • pp.187-196
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    • 2010
  • Recently, people have been suffering from stress-related fatigue and psychological disorders. Most people depend on medicine for pain relief; many treat pain also through alternative medicine or replacement therapy. However, drug therapy has many side effects, including increased stress after the therapy. In comparison, alternative therapies such as massage and foot reflexology are less damaging to the body, and such therapies can be provided without physical or psychological discomfort. In this regard, the author had previously co-developed color foot reflexology, which combines the merits of color therapy and foot reflexology; color foot reflexology has been shown to have beneficial effects without undue pain. This study investigates the effects of color foot reflexology on the physiological response of the body by comparing the body’s response to the signal with that to the placebo. Healthy adult subjects were selected for the experiment, which was conducted under optimal experimental conditions and design. The results indicated that when stimulated, parasympathetic nerves increased in HRV and that blood pressure, pulse, body heat, peripheral blood flow were dramatically activated. However, the results for the placebo indicated minimal changes or irregular outcomes. The results provide strong evidence for the beneficial effects of the color foot reflexology instrument on the autonomic nervous system and on the physiological response of the body. Future research is warranted to verify the results of the current study by examining patients suffering from diseases and disorders arising from irregular physiological functions in the context of the foot.

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Thermophysiological Responses of Wearing Safety Hat for Working at a Hot Environment (서열환경하에서 안전모 착용시의 인체생리학적 반응)

  • 박소진;김희은
    • Journal of the Korean Society of Clothing and Textiles
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    • v.26 no.1
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    • pp.74-82
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    • 2002
  • The present study is aimed to investigate the effect of the safety hat on the balance of body temperature by observation of the physiological response under hot working environment. The experiment was carried out in a climate chamber of 3$0^{\circ}C$, 50%RH for 70 minutes. To compare the two kinds of safety hat, 5 healthy male subjects worn safety hat without hole (called 'without hole') or safety hat with hole (called 'with hole') according to a randomized cross-over design. The main results of this study are as fellows: Rectal temperature and heart rate were significantly lower level in 'with hole'than in 'without hole'. The mean skin temperature was significantly higher in 'without hole'than in 'with hole'. Blood pressure were significantly low in 'with hole'. Sweat rate which was measured by weight loss before and after experiment was higher in 'without hole'. In subjective ratings, subjects replied more hot, more uncomfortable and more wet, they felt more fatigue in condition of 'without hole'. Work ability which was measured by a grip strength dynamometer was higher in 'with hole'. Safety hat which can be used for safety of the brain in work place is meaningful device of behavioral thermoregulatory response under the hot working environment. The safety hat which is designed for proper ventilation and hygiene can maintain the homeostasis of body temperature by releasing body temperature efficiently.

The Relationship between Perceived Stress and Coping Strategies in Patients with Chronic Low Back Pain (만성요통 환자들에서 스트레스지각과 대응전략 간의 관계)

  • Shin, Yoon-Sik;Koh, Kyung-Bong
    • Korean Journal of Psychosomatic Medicine
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    • v.10 no.1
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    • pp.18-26
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    • 2002
  • Objectives : The object of this study was to investigate the relationship between coping strategies and perceived stress or pain discomfort in patients with chronic low back pain. 80 patients with chronic low back pain and 100 normal controls participated in this study. Methods: Global assessment of recent stress (GARS) scale and Stress Response Inventory (SRI) were used to measure perception for stressors and stress responses. Coping scale and pain discomfort scale were used to measure coping strategies and pain perception. Results : Scores of perceived stress related to work or job, interpersonal relationship, changes in relationship, sickness or illness and the total scores on the GARS scale were significantly higher in those with chronic low back pain than normal controls. Scores of the SRI fatigue subscale scored significantly higher in those with chronic low back pain than normal controls. No significant difference was found on total scores of the pain discomfort scale between those with chronic low back pain and normal controls. The patients with chronic low back pain scored significantly higher on planful problem solving and positive reappraisal than normal controls. In the patient group, pain perception had significant positive correlations with total scores of the SRI and scores of stress perception related to illness or injury. The extent of escape-avoidance showed significant negative correlations with age, whereas the extent of distancing or escape-avoidance had significant negative correlations with the level of education. Significant difference was also found in accepting responsibilities between male subjects and females. However, no significant correlations were found between coping strategies and perceived stressors, stress responses or pain perception. Conclusion : The results suggest that patients with chronic low back pain were more likely to use more active coping strategies than normal controls, though the former had more perception for stressors than the latter. It was also found that coping strategies used by the patients were associated with sociodemographic factors, but that they were not associated with perceived stressors, stress responses or pain perception.

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Analysis of the Correlation between Human Sensibility and Physical Property of luminous Sources -Focused on Response according to Character of Color Temperature by luminous Sources- (건축조명광원의 광학적 특성에 따른 인간의 감성반응 분석 -조명광원별 색온도 특성에 따른 반응을 중심으로-)

  • Lee, Jin-Sook;Oh, Do-Suk
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.19 no.5
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    • pp.9-16
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    • 2005
  • The purpose of this research is to acquire emotional data on luminous source by measuring and evaluating human emotional response to the change of the optical feature of luminous environment Luminous sources used in actual architectural space were selected with the optical feature of luminous soured then to measure and analysis human emotional response on Luminous Source. As a result of that 1) In the result of performance measurement by the item of the clear vision of an optic function the fluorescent lamp of daylight indicated the most excellent Performance. 2) In the item of fatigue and stress, the metal halide lamp and mercury lamp showed the most 3) In $\ulcorner$ suitable in light$\lrcorner$, $\ulcorner$a similar with daylight$\lrcorner$ adjective of the amenity item the fluorescent lamp of daylight which color temperature was high turned up to be high also, in $\ulcorner$brilliant$\lrcorner$, adjective, the metal halide lamp and mercury lamp turned up to be low. 4) In the result of factor analysis, three factors $\ulcorner$activity$\lrcorner$, $\ulcorner$potency$\lrcorner$, $\ulcorner$evaluation$\lrcorner$ were abstracted and $\ulcorner$activity$\lrcorner$ factor has the most influential on evaluating the mood of interior space. 5) For the affection in the mood evaluation by each luminous sources, $\ulcorner$activity$\lrcorner$ factor was the most influential by metal halide lamp and fluorescent lamp of daylight, $\ulcorner$potency$\lrcorner$ factor was most influential by kind of incandescent lamp, $\ulcorner$evaluation$\lrcorner$ factor was most influential by fluorescent lamp of low color temperature.