• 제목/요약/키워드: Cycle variability(CV)

검색결과 5건 처리시간 0.022초

SI가솔린 기관에서 흡기조성에 따른 연소 및 배기특성에 관한 실험적 연구 (A Experimental study on combustion and exhaust characteristics by intake composition in SI gasoline engine)

  • 최일동;김치원;윤창식;김기복;이병호
    • 한국산업융합학회 논문집
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    • 제20권1호
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    • pp.56-66
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    • 2017
  • In this experimental study, it is designed and used the test engine bed which is installed with the exhaust gas recirculation, and in addition to equipped using by oxygen adder. It has been tested and analyzed the combustion and emission characteristics, cycle variability and engine performance by controlling the oxygen volume fraction, EGR rate, engine speed and equivalence ratio.

Assessment of Gait Ability of Subjects With Chronic Ankle Instability During an Inter-trial Variability Gait Task According to Changes in Gait Speed

  • Jeonghan Kwon;Jongduk Choi
    • 한국전문물리치료학회지
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    • 제30권4호
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    • pp.268-274
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    • 2023
  • Background: Ankle sprains occur frequently among humans who undertake various body movements. Diverse walking environments and dual tasks, that can affect ankle sprains, have been studied. However, there is a lack of research on inter-trial variability according to the changes in gait speed. Objects: The purpose of this study was to compare the adaptive ability of walking between the subjects with chronic ankle instability and healthy adults while performing a walking task with different walking speeds. Methods: In this study, 24 people in the chronic ankle instability group and 24 people in the healthy ankle group were selected as subjects. The length of the pre-measurement and the actual walking measurement were both set to 4.6 m. Once the subjects entered the measurement section, they changed their gait speed according to the randomly assigned speed change. Gait was measured twice and the average value was used for the analysis. Results: The coefficient of variation (CV) of cycle time in subjects with chronic ankle instability showed a significant difference in all cases except when the subjects changed their speed from preferred to slow and from slow to preferred. The CV of step length demonstrated a significant difference in all cases except for the change from slow to preferred and from preferred to fast. The cycle time and step length differential showed a significant difference only when the subjects changed the speed from slow to fast. Conclusion: The subjects with chronic ankle instability were found to have significantly reduced walking adaptability while performing inter-trial variability tasks with different gait speeds compared to healthy subjects.

월경통 치료 전과 후의 적외선체열영상 및 피부저항변이도 변화에 대한 연구 (A Study on the Change of Digital Infrared Thermographic Imaging and Skin Resistance Variability before and after Treatment of Dysmenorrhea)

  • 김현주;이용현;손영주
    • 대한한방부인과학회지
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    • 제26권2호
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    • pp.88-103
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    • 2013
  • Purpose: The aim of this study was to examine the effect of oriental diagnosis and treatment for dysmenorrhea patients on lower abdominal temperature and Skin Resistance Variability(SRV). Methods: We studied twenty-five dysmenorrhea patients, who visited Oriental Medicine Hospital of ${\bigcirc}{\bigcirc}$ University for 10 months(Sep. 2011~Jun. 2012). Patients with organic disease such as endometriosis, uterine myoma and pelvic inflammatory disease were excluded from this study. We prescribed 3 types of treatments, herbal medicine, acupuncture, and moxibustion, for one menstrual cycle. Digital Infrared Thermographic Imaging(DITI), 7-Zone-Diagnostic System(CP-6000A), VAS(Visual analog scale) and MVRS(Multidimensional verbal rating scale) were conducted before and after the treatment. The result of DITI, 7-Zone-Diagnostic System, VAS and MVRS before and after treatment were compared in order to objectively assess the therapeutic effect. Results: When we compared the results of DITI, CV4 temperature after treatment was increased compared with that of before, and temperature difference between CV12 and CV4 after treatment was decreased compared with that of before. But there was no significant difference. When we compared the results of 7-Zone-Diagnostic System at 1st and 2nd trial, the height of 1~5 area was lower than that of before. And at 1st and 2nd trial, the height of 6, 7 area was higher than that of before, but there were no significant difference in most. When we compared the results of VAS and MVRS, VAS and MVRS after treatment was significantly decreased compared with that of before(p<0.01). Conclusions: This study shows that oriental diagnosis and treatment for dysmenorrhea patients affects the results of DITI. Further study will be needed.

인간공학적 방법을 이용한 사이클 선수의 경기력 평가 (우수선수의 경기력 벤치마킹을 중심으로) (Cyclist's Performance Evaluation Used Ergonomic Method)

  • 하종규;장영관;기재석
    • 대한안전경영과학회:학술대회논문집
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    • 대한안전경영과학회 2009년도 추계학술대회
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    • pp.15-24
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    • 2009
  • Cycling that transform human energy into mechanical energy is one of the man-machine systems out of sports fields. Benchmarking means " improving ourselves by learning from others ", therefore benchmarking toward dominant cyclist is necessary on field. the goals of this study were to provide important factors on multi-disciplines (kinematics, physiology, power, psychology) for a tailored-training program that is suitable to individual characteristics. Two cyclist participated in this study and gave consent to the experimental procedure. one was dominant cyclist (years:21 yrs, height:177 cm, mass:70 kg), and the other was non-dominant cyclist(years:21, height:176, mass:70). Kinematic data were recorded using six infrared cameras (240Hz) and QTM (software). Physiological data (VO2max, AT) were acquired according to graded exercising test with cycle ergometer and power with Wingate test used by Bar-Or et. al ( 1977) and to evaluate muscle function with Cybex. Psychological data were collected with competitive state anxiety inventory (CSAI-2) that were devised by Martens et. al (1990) and with athletes' self-management questionnaire (ASMQ) of Huh (2003). It appears that the dominant's CV(coefficient of variability) was higher than non-dominant's CV in Sports Biomechanics domain, that the dominant's values for all factors ware higher than non-dominant's values in physical, and physiological domain, and their values between cognitive anxiety and somatic anxiety were contrary to each other in psychology. Further research on multi-disciplines may lead to the development of tailored-optimal training programs applicable with key factors to enhance athletic performance by means of research including athlete, coach and parents.

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인간공학적 방법을 이용한 사이클 선수의 경기력 평가 (우수선수의 경기력 벤치마킹을 중심으로...) (Cyclist's Performance Evaluation Using Ergonomic Method (Focus to Benchmarking Elite Cyclist's Performance))

  • 하종규;장영관;기재석
    • 대한안전경영과학회지
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    • 제12권1호
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    • pp.51-57
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    • 2010
  • Cycling that transform human energy into mechanical energy is one of the man-machine systems out of sports fields. Benchmarking means "improving ourselves by learning from others', therefore benchmarking toward dominant cyclist is necessary on field. The goals of this study were to provide important factors on multi-disciplines (kinematics, physiology, power, psychology) for a tailored-training program that is suitable to individual characteristics. Two cyclists participated in this study and gave consent to the experimental procedure. One was dominant cyclist (years: 21 yrs, height: 177 cm, mass: 70 kg), and the other was non-dominant cyclist (years: 21, height: 176, mass: 70). Kinematic data were recorded using six infrared cameras (240Hz) and QTM (software). Physiological data (VO2max, AT) were acquired according to graded exercising test with cycle ergometer and power with Wingate test used by Bar-Or et. al (1977) and to evaluate muscle function with Cybex. Psychological data were collected with competitive state anxiety inventory (CSAI-2) that was devised by Martens et. al (1990) and athletes' self-management questionnaire (ASMQ) of Huh (2003). It appears that the dominant's CV of ankle joint angle was higher than non-dominant's CV and dominant's pedaling pattern was consistent in biomechanics domain, which the dominant's values for all factors ware higher than non-dominant's values in physical, and physiological domain, and their values between cognitive anxiety and somatic anxiety were contrary to each other in psychology. Further research on multi-disciplines may lead to the development of tailored-optimal training programs applicable with key factors to enhance athletic performance by means of research including athlete, coach and parents.