• 대한기계학회논문집
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• 제18권11호
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• pp.3098-3107
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• 1994

The central burst defects, so-called chevroning, in wire drawing are analyzed by the rigid-plastic finite element method. The occurrence of central burst defects in wire drawing is estimated by the distribution of the hydrostatic pressure around the central part of the workpiece. It has been possible to obtain numerical boundaries which, in reduction in area vs. semicone angle plane, divide the safe and the danger zones, depending on friction factors and material properties. Based on the results of the analysis, it is suggested that the previous criterion derived from the upper bound analysis should be modified for better prediction of the defects. The back tension and the billet with a spherical hole on the central axis are also included in the analysis of the defects.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집A
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• pp.402-406
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• 2000

Strain energy function of the isoprene rubber was accurately determined by the experiments of uniaxial tension, planar tension, biaxial tension and volumetric compression. Deformation behavior of alternatively laminated structure of elastomer and reinforced aluminium layers, was analysed by Finite Element method. As a result, Ogden strain energy function obtained from the experiments describes the hyperelastic characteristics of the rubber very well. The compressibility of the rubber reduces axial stiffness of the structure. The axial stiffness of alternatively laminated structure being larger than shear stiffness. Which enables the structure to be shear-deformed easily.

• The Korean Journal of Pain
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• 제7권1호
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• pp.88-91
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• 1994

Headache, like low back pain, is one of the most common of pain conditions. Many data suggest that nerve block can be one of effective treatments in managing headache except pure psychologic or surgical origin, because mechanism of headaches have neurologic, vascular or local tissue pathology. We experienced two types of headache; episodic tension-type headache, and benign exertional headache; successful treatment consist of nerve block and modulation of exercise, respectively.

• 한국강구조학회 논문집
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• 제21권2호
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• pp.165-173
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• 2009

현수교 행어케이블은 일부가 클램프로 구속되어 있어 단일 케이블 모델을 기반으로 한 기존의 장력추정 방법들은 휨감성의 영향이 큰 짧은 케이블 일수록 오차가 커지게 된다. 따라서 최근에 유한요소모델 기반의 역해석 기법 및 시스템인식 기법을 이용한 장력추정 방법이 제안되었다. 본 논문은 광안대교 행어케이블을 대상으로 역해석 기법 및 시스템인식 기법을 이용한 장력추정 방법의 적용성을 비교 검토 하였다. 장력추정결과 유한요소모델을 기반으로 한 역해석 기법 및 시스템인식 기법은 기존의 현이론 및 선형회귀법에 의한 장력추정 방법에 비해 고유진동수 오차를 기준으로 보다 높은 신뢰성을 가지고 장력을 추정하였다. 하지만 모델기반의 장력추정 방법은 유한요소모델의 정확도에 따라 그 오차가 다르게 나타날 수 있다. 특히, 짧은 케이블 일수록 경계조건의 영향을 많이 받기 때문에 가능하다면 실험을 통해 경계조건을 명확히 파악하는 것이 중요하다. 시스템인식 기법을 이용한 장력추정 방법은 다양한 경계조건을 용이하게 고려할 수 있으며, 또한 입력되는 계측 고유진동수의 개수에 민감하지 않기 때문에 그 효용성이 높다고 할 수 있다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2001년도 추계학술대회 논문집
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• pp.121-124
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• 2001

On-line prediction model which calculate roll force, roll power and forward slip of continuous hot strip rolling was built based on the results of plane strait rigid-viscoplastic finite element process model. Using the integrated FE process model, a series of finite element simulation was conducted over the process variables, and the influence of various process conditions on non-dimensional parameters was inspected. The prediction accuracy of the proposed on-line model under front and back tension is examined through comparison with predictions from a finite element process model over the various process conditions. In addition, we examined the validity of the on-line prediction model through comparison with roll force of experiment in hot rolling.

• Korean Journal of Acupuncture
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• 제33권3호
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• pp.95-101
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• 2016

Objectives : This study aims to overview the therapeutic mechanism of back-shu points in terms of sympathetic visceral motor nervous system. Methods : Studies about autonomic nervous system, and studies and ancient texts about back-shu points were reviewed. We interpreted possible mechanism of back-shu points considering similarities of anatomical and physiological characteristics of back-shu points and visceral motor nervous system. Results : Afferent signals for organ lesions that can develop the symptoms of autonomic neurological symptoms, pain, hyperalgesia through the skin segment. Through a physical examination of the myotome and dermatome, it is possible to diagnose segmental disorders. Treatment stimulation of the thick fibers of the disorder segment skin can reduce abnormal autonomic influence over the sympathetic reflex mechanism. In addition, if spinal muscles are relaxed, the pressure on the nerve roots could be reduced and consequently the hyperactivity of the sympathetic visceral motor signal would be suppressed. Conclusions : The back-shu points treatments work through the mechanism of the sympathetic nervous reflex. Moreover, segmental acupuncture can reduce tension of the spinal muscles, thereby improving pathological conditions of the sympathetic nervous system.

• KCI Concrete Journal
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• 제12권2호
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• pp.85-93
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• 2000

Potentially significant mechanical improvements in tension can be achieved by the incorporation of randomly distributed, short discrete fibers in concrete. The improvements due to the incorporation fibers significantly influence the composite stress - strain ($\sigma$-$\varepsilon$) characteristics. In general incorporating fibers in a plain concrete has relatively small effect on its precracking behavior. It, however, alters its post-cracking behavior quite significantly, resulting in greatly improved ductility, crack controls, and energy absorption capacity (or toughness). Therefore, a thorough understanding the complete tensile stress - strain ($\sigma$-$\varepsilon$) response of fiber reinforced concrete is necessary for proper analysis while using structural components made with fiber reinforced concrete. Direct tensile stress applied to a specimen is in principle the simplest configuration for determining the tensile response of concrete. However, problems associated with testing brittle materials in tension include (i) the problem related to gripping of the specimen and (ii) the problem of ensuring centric loading. Routinely, indirect tension tests for plain concrete, flexural and split-cylinder tests, have been used as simpler alternatives to direct uniaxial tension test. They are assumed to suitable for fiber reinforced concrete since typically such composites comprise 98% by volume of plain concrete. Clearly since the post-cracking characteristics are significantly influenced by the reinforcing parameters and interface characteristics, it would be fundamentally incorrect to use indirect tensile tests for determining the tensile properties of fiber reinforced concrete. The present investigation represents a systematic look at the failure and toughening mechanisms and macroscopic stress - strain ($\sigma$-$\varepsilon$) characteristics of fiber reinforced concrete in the uniaxial tension test. Results from an experimental parametric study involving used fiber quantity, type, and mechanical properties in the uniaxial tension test are presented and discussed.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제14권5호
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• pp.532-536
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• 2008

본 연구는 Laban이 제시한 모션 분석 기법을 이용하여 모션의 긴장도를 측정하는 방법을 제안한다. 이러한 긴장도 값을 이용하면 캐릭터 모션과 배경음악간의 자동적 동기화를 위한 기준값으로 사용할 수 있다. Laban의 모션 분석 기법, 즉 LMA는 모션을 Effort라고 명명된 4개의 시공간적 요소로 나누고 각 4개의 Effort마다 2가지 상반된 기준을 제시함으로써 모션을 분석하도록 하였다. 이러한 기준을 양적으로 측정하기 위해 우리는 운동학, 역학에 기초한 수식을 제안하고 이를 통해서 계산된 실제 긴장도 값을 실험 데이타에 근거하여 조정하였다. 실험을 통해 제안한 긴장도 측정 결과는 어느 정도 사람의 반응과 비슷한 정도의 순위 판별 능력을 보였다.

• PNF and Movement
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• 제21권2호
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• pp.185-192
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• 2023

Purpose: This study aimed to confirm the effectiveness of the diaphragm stretching technique as a treatment method for low back pain by evaluating maximum inspiratory pressure, maximum expiratory pressure, and changes in back mobility in patients with low back pain. Methods: Thirty-four patients with low back pain were randomly divided into two groups: an experimental group and a control group. The diaphragm stretching technique was conducted in the experimental group, and the placebo intervention was conducted in the control group. The diaphragm stretching technique was conducted once, maintaining tension for 7 min. The placebo intervention was conducted in the same position as the diaphragm stretching technique, but with only light contact maintained without pressure. Maximum inspiratory pressure, maximum expiratory pressure, and back mobility were measured before and after the intervention, and the changes were compared and analyzed. A paired sample t-test was used to compare measurements within the group before and after the intervention. An independent t-test was used to compare the experimental and control groups. Statistical significance (α) was set at 0.05. Results: In the experimental group, maximum inspiratory pressure, maximum expiratory pressure, and back mobility increased significantly after the intervention (p < 0.05). However, there was no significant difference in the changes in all areas of the control (p > 0.05). As a result of comparative analysis of changes before and after the intervention, there were significant differences in maximum inspiratory pressure, maximum expiratory pressure, and back mobility only in the experimental group (p < 0.05). Conclusion: The diaphragm stretching technique improved maximum inspiratory pressure, maximum expiratory pressure, and back mobility compared to the placebo intervention. Therefore, the diaphragm stretching technique can be recommended as a physical therapy intervention to improve pain in patients with LBP.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2003년도 춘계학술발표대회 개요집
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• pp.155-158
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• 2003

Orbital GTA welding is used in the pressure pipe line of auto-mobile, LNG and plant piping. To weld the pipe line safely, to some extent, the back bead must be formed in the root pass. In the plate welding the back bead can be observed, but in the pipe welding, the back bead can not be observed directly. In the welding around circumference, the parameters such as gravity, surface tension and arc force are different at each position. And then D/B for welding condition at each position are required. We also studied about the setting of the optimum orbital welding condition by controlling heat input.