• Title/Summary/Keyword: Pivot

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Successful Factor Analysis of 540° Dwihuryeochagi to Apply Free Style Poomsae of Taekwondo (태권도 자유 품새에 적용하기 위한 540° 뒤후려차기의 성공요인 분석)

  • Yoo, Si-Hyun;Ryu, Ji-Seon;Park, Sang-Kyoon;Yoon, Suk-Hoon
    • Korean Journal of Applied Biomechanics
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    • v.23 no.4
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    • pp.285-294
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    • 2013
  • The purpose of this study was to provide fundamental information for success factors of techniques through kinematic analysis including coordination of lower extremities and landing stability according to the success and failure of $540^{\circ}$ Dwihuryeochagi in Taekwondo. Twenty Taekwondo athletes: ten success group (S, age: $22.3{\pm}1.8$ yrs, height: $172.1{\pm}5.4$ cm, body mass: $64.4{\pm}4.2$ kg) and ten failure group (F, age: $22.3{\pm}1.8$ yrs, height: $172.1{\pm}5.4$ cm, body mass: $64.4{\pm}4.2$ kg) participated in this study. Three-dimensional motion analysis using a system of 3 video cameras with a sampling of 60 fields/s was performed during the competition of $540^{\circ}$ Dwihuryeochagi. Motions were divided into five events: pivot foot landing (E1), pivot foot toe off (E2), COM max height (E3), kick impact (E4) and landing (E5). At E1, the stride width was greater for S than for F (p<.05) while the time was greater for S than for F during P4 (p<.05). At E4, knee angle was greater for S than for F (p<.05). At E5, hip angle was greater for S than for F (p<.05) while kick distance was greater for S than for F (p<.05). Furthermore, at P3, the time would be related to kicking velocity (p<.05), while at P4, the time, range of hip angle and knee angle would be related to kick distance (p<.05). At P1, COM horizontal velocity would be related to COM vertical velocity of P1 and P2 (p<.05). Based on the findings, success factors of $540^{\circ}\acute{y}$ Dwihuryeochagi were COM horizontal velocity of P1, COM vertical velocity of P2, the time, kick distance, velocity, angle of lower extremities and coordination of P3-P4.

The Relationship between Bone Bruise in MR-Imaging and the Degrees of Acute Anterior Cruciate Ligament Injury (급성 전방십자인대 손상 시 자기공명영상에서 나타나는 골멍과 전방십자인대 손상 정도의 관계)

  • Jeong, Hwa-Jae;Shin, Hun-Kyu;Ko, Chun-Suk;Kim, Jang-Hwan
    • Journal of the Korean Arthroscopy Society
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    • v.16 no.1
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    • pp.17-25
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    • 2012
  • Purpose: The aim of this retrospective study was to evaluate the relationship between appearance and size of bone bruise and severity of anterior cruciate ligament (ACL) injury with magnetic resonance imaging (MRI), furthermore, to identify the mechanism of ACL injury by analyzing the footprint of bone bruise. Materials and Methods: Sixty-five subjects who was taken an MRI within 6 weeks after acute ACL injury were studied. All MRI showed ACL injury and associated bone bruises. Bone bruises were analyzed using Costa-Paz classification based on appearance and location and also scored using Kornaat bone bruise grading system based on size and location. The severity of the ACL injury was graded using a 4-point system (ie, grade 0-3) with oblique coronal MRI. Results: There was statistically significant correlation between Costa-Paz classification of bone bruises in lateral femoral condyle and grade of ACL injury. There were more type 2 lesions in partial tear group (grade 1, 2), however, type 3 lesions of Costa-Paz classification in complete tear group (P=0.037). Significant positive correlations were observed between Kornaat total bone bruise score and grade of ACL injury (P=0.014). Most common ACL injury mechanism was pivot shift injury. Other mechanisms were clip valgus injury, phantom foot injury, and hyperextension injury. Conclusion: It is highly suggested that appearance and size of bone bruise is related to severity of ACL injury after acute ACL injury. The foot print of bone bruise provides valuable clues to identify ACL injury mechanism.

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Fasting of the Mind and Quieting of the Mind: A Comparative Analysis of Apophatic Tendencies in Zhuangzi and Cataphatic Tendencies in Daesoon Thought

  • ZHANG Rongkun;Jason GREENBERGER
    • Journal of Daesoon Thought and the Religions of East Asia
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    • v.2 no.2
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    • pp.33-50
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    • 2023
  • 'Fasting of the Mind (心齋, ch. xīn zhāi)' is arguably the most important concept within the practical approach to the spiritual cultivation formulated by the Daoist philosopher, Zhuangzi (莊子). Most scholars have interpreted 'Fasting of the Mind' as an apophatic practice centered around the aim of the 'Dissolution of the Self (喪我, ch. sàng wŎ).' The Korean new religious movement, Daesoon Jinrihoe (大巡眞理會), can be shown to instead consistently utilize cataphatic descriptions of spiritual cultivation based on the 'quieting of the mind (安心, kr. anshim)' and 'quieting of the body (安身, kr. anshin)' with the highest attainable state referred to as the 'Perfected State of Unification with the Dao (道通眞境, kr. Dotong-jingyeong).' While the language used by Zhuangzi and Daesoon Jinrihoe appears quite different on a superficial level, a deeper examination shows that these rhetorical framings are likely negativistic and positivistic descriptions of the same, or at least reasonably similar, phenomena. Zhuangzi, who focused primarily on the body, mind, and internal energy, cautioned practitioners that 'mere listening stops with the ears (聽止於耳, ch. tīng zhǐ yú ěr)' and 'mere recognition stops with the mind (心止於符, ch. xīn zhǐ yú fú).' He therefore encouraged cultivators of the Dao to 'listen with the spirit (聽之以氣 ch. tīng zhī yǐ qì).' The main scripture of Daesoon Jinrihoe states that "The mind is a pivot, gate, and gateway for gods; They, who turn the pivot, open, and close the gate, and go back and forth through the gateway, can be either good or evil (心也者, 鬼神之樞機也, 門戶也,道路也)," and the Supreme God of the Ninth Heaven (九天上帝, kr. Gucheon Sangje) even promises to visit anyone who possesses a 'singularly-focused mind (一心, kr. il-shim).' In both these approaches, there is a sense of what must be kept out of the mind (e.g., external disturbances, strong emotions, malevolent entities) and what the mind should connect with to attain spiritual progress (e.g., spirit, singular focus, the Supreme God). The observations above serve as the main basis for a comparison between the apophatic descriptions of cultivation found in Zhuangzi and their cataphatic counterparts in Daesoon Thought. However, the culmination of this nuanced comparative exploration reveals that while the leanings of Zhuangzi and Daesoon Thought generally hold true, ultimately, both systems of cultivation transcend the categories of apophatic and cataphatic.

A Study on Zhang Zhong-Jing's Ideology of Health Cultivation by Protecting Yang Analyzed from the Usage of Guizhi in Treatise on Cold Damage (종(从)"상한론(伤寒论)"용계지간중경적호양양생사상(用桂枝看仲景的护阳养生思想))

  • Liu, Chung-Yuan
    • Journal of Korean Medical classics
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    • v.22 no.1
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    • pp.87-91
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    • 2009
  • "Treatise on cold damage and miscellaneous disease" is a ancient formula records on keeping in good health, provided "Internal classic" is a ancient codes on keep in good health. It can be inferred that Zhang Zhongjing was a first inheritor of academic ideology from "formula followed by establishment of the therapeutic principles". Before writing and compiling the "Treatise on cold damage and miscellaneous disease", Zhang zhongjing got the essence of "Internal classic" after composing and utilizing "Plain Questions", "Miraculous pivot and classic of difficult issues", so all the theory foundations of "Treatise on cold damage and miscellaneous disease" came from "Internal classic". The keynote of internal classic lies in obeying the Yin and Yang in natural world and preserving and maintaining the yang-qi of human body to attain the longest life-span. Zhang assimilated the essence of "Internal classic" and then generated a new ideological system - "Treatise on cold damage and miscellaneous disease" when studying it. This article is to expound ideology inheritance of keeping in good health by protecting Yang in "Internal classic" from analyzing the usage of Guizhi in "treatise on cold damage diseases".

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A study on the design of triggering pulse generator for the triggered vacuum switch (진공스위치 트리거 발생기 설계에 관한연구)

  • Kim, Mu-Sang;Son, Yun-Gyu;Park, Ung-Hwa;Lee, Byeong-Jun
    • Proceedings of the Korean Vacuum Society Conference
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    • 2016.02a
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    • pp.201.2-201.2
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    • 2016
  • The triggered vacuum switch (TVS) is widely used as a high power switch in the field of pulsed power application. TVS can produce current of higher than 100 kA within a microsecond after being triggered. A triggering high voltage pulse generator supplies a high voltage signal to the trigger system to initiate the discharge between a trigger pin and one of main electrode. The trigger system, which consists of a tungsten trigger electrode and cylindrical ceramic insulator around it, is normally installed at the center of main cathode electrode. The discharging characteristics of the trigger system strongly depend on the geometry, electrode material, vacuum pressure and so on. In addition, we especially will focus on the developing a triggering pulse generator, which can vary not only value of voltage but also pulse duration, because its properties gives pivot influences on the TVS discharge. To verify such effects, we made a 3.3 kJ TVS set-up initially. Thus we will discuss some of prominent results from 3.3 kJ TVS system. In parallel we will show on the design of 300 kJ TVS system for the high current in the future.

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The Investigation of Residential Area Changes by the Provision of Urban Linear Parks - Case Studies of the Regenerated Street Parks and the Uncovered Stream Parks in Seoul - (선형공원 조성에 의한 주변 주거지의 변화 분석 - 서울시 재생 가로공원과 복원하천 수변공원 사례 연구 -)

  • Lee, Ju-Eun;Yang, Woo-Hyun
    • Journal of the Korean housing association
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    • v.27 no.6
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    • pp.45-55
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    • 2016
  • This study focused on the changes of residential area around the linear park. The goal of this study is to determine the value of linear park at the view of residents and discover the interaction between the linear park and the residential area around it. To investigate this goal, the researcher chose case sites, the regenerated linear park and the uncovered stream park. This study analyzed the site around the linear parks with four points of view, the organization of urban Fabric, architecture, the economic value of the site and the behavior of residents. This research adopted several research methodologies like aerial photograph analysis, road-view analysis, paper research, and field study, observation, and expert interview to approach as both quantitative and qualitative analysis. With that variation characteristic, the researcher determines the influence of linear park through the residential area around them. As the result, linear park gives positive effects of running sustainable residential area around them and acting as the pivot for the residential area. Also for the future, designers must consider this interactive relation between the linear park and residential area with the wide point of view.

A study on the structural characteristics and roll behavior of suspension for the section profile of torsion beam (토션빔의 단면형상에 다른 현가계의 구조적 특성과 롤 거동에 관한 연구)

  • 이동찬;변준형
    • Transactions of the Korean Society of Automotive Engineers
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    • v.7 no.9
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    • pp.195-202
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    • 1999
  • The kinematic and complicance characteristics of torsion beam axle is structurally related to the location and section profile of torsion beam and the span from body mounting point to wheel center. This paper presents the effect of section properties in torsion beam on the structural characteristics and roll behavior of suspension. The structural characteristics is on the maximum stress on the welding area of torsion beam and the roll behavior is on roll steer and roll-camber of suspension which are important for controllability and stability in cornering. Four factors are used for the section design of torsion beam, which are thickness , midline length, are inner radius, and sector half angle . Through the structural and quasi-static analysis made for six torsion beam axle models, it can be noticed that roll steer and the structural durability of suspension are closely related to warping constant and shear center in section properties of torsion beam.

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Study on the Prevention of Pad Fluttering with the Variation of Preload in a Tilting Pad Journal Bearing (예압 변경을 통한 틸팅패드 저널베어링의 패드 Fluttering 방지에 관한 연구)

  • 박철현;김재실;하현천;양승헌
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.14 no.4
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    • pp.344-351
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    • 2004
  • Tilling pad journal bearings have been widely used to support the rotors of the high rotating machinery such as steam and gas turbines owing to their inherent dynamic stability characteristics. However, serious bearing problems such as fatigue damage in the upper unloaded pad, the break of locking pins and the wear of pinholes etc. by pad fluttering are frequently taken place in the actual steam turbines. The purpose of this paper is to investigate the mechanism of pad fluttering and to suggest the useful design guideline(application of preload, m) for the purpose of preventing bearing problems by pad fluttering in a tilting pad journal bearing. It is estimated that upper pad is easy to flutter because the film shape of the upper pad is diverged by moment acting on pivot point. This paper suggests that effective preload range(m $\geq$ 0.5) in order to be statically loaded pad under all operating conditions. Also, design modified bearing is suggested for the adjustment in actual steam turbines. And bearing and rotor dynamic analysis are performed to identify bearing characteristics and to verify the reliability of rotor-bearing system.

Pan-tilt Motion Generation of Robot Eye by Using a Pair of Push-pull Wires (한 쌍의 푸쉬-풀 와이어를 이용한 로봇 안구의 팬-틸트 모션 생성)

  • Jung, Chan-Yul;Oh, Kyung-Geune;Park, Shin-Suk;Kim, Seung-Jong
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.21 no.1
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    • pp.3-8
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    • 2011
  • This paper introduces a robot eye module, of which two degree-of-freedom motions, i.e. panning and tilting, are driven by a pair of wires. The main feature of the module is that each wire can generate push-pull motion without buckling. It is thanks to a Teflon tube which guides the path of the moving wire. End points of the tube and wire have pivot elements so that a smooth push-pull motion is produced even when the end point of wire is moved by eye rotation. This mechanism helps the eye module to be very compact. In this paper, the structure of the robot eye module is introduced in detail, and the required motor angles for a certain direction of eye line are investigated analytically and experimentally.

Experimental Study on Different Principles of Variable Stiffness Actuators (가변강성 액추에이터의 원리에 대한 비교 실험 연구)

  • Baek, Kyu Yeol;Kim, HyunGyu;Seo, TaeWon
    • Journal of the Korean Society for Precision Engineering
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    • v.32 no.12
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    • pp.1049-1054
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    • 2015
  • Nowadays, there are many researches involving structural actuators, which have adjustable stiffness; they are also called variable stiffness actuators (VSA). The VSAs can adjust the characteristics of actuators for various functions and human-machine safety. This paper describes the design and analysis of two types of VSAs. To adjust stiffness, the actuators are controlled by a principle of lever ratio mechanism, by changing a pivot position or a spring position in the structure with springs. To make the principle workable, the designs are simplified by using a ball screw system with a motor. Each structure shows different static properties with variable rates of stiffness. We have also shown the experimental verification of the dynamic performance of the two types of VSAs. This research can be applied to various industrial fields, where humans work in conjunction with robots.