• 제목/요약/키워드: Stability and stabilization

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Effects of Sensorimotor Training on Postural Stability and Pain in Patients with Chronic Low Back Pain

  • Kang, Kwonyoung
    • 국제물리치료학회지
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    • 제12권2호
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    • pp.2314-2322
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    • 2021
  • Background: Back pain is associated with a high risk of recurrence. Various physical therapy techniques for back pain have been studied, including reprogramming the central nervous system by integrating sensation and motion with sensory exercise training. Objectives: To aimed verify the effectiveness of sensorimotor training in improving postural stability and pain levels. Design: A randomized controlled trial. Methods: The study population was randomized into a sensory exercise training group and trunk stabilization training group and treated three times a week for 4 weeks. Each group took part in sensorimotor training for 15 minutes or lumbar stabilization exercise for 15 minutes. Results: After the intervention both groups showed Improvements in the variables. There was a significant difference in the dynamic postural stability, limit of stability, and modified visual analog scale scores in the sensorimotor training group compared to the lumbar stabilization exercise group (P<.05). Conclusion: Sensorimotor training appears to be an effective physical therapy exercise program that can be applied in patients with low back pain to improve muscle control ability.

KSR-III 로켓엔진의 연소 안정성 평가 (Stability Rating of KSR-III Rocket Engine)

  • 손채훈;김영목
    • 한국항공우주학회지
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    • 제32권3호
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    • pp.95-101
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    • 2004
  • 액체 로켓엔진 개발과정에서 수행되는 여러 가지 시험 중 연소 안정성 평가 시험을 통해, KSR-III 로켓엔진의 연소 안정성을 평가하였다. 안정성 평가시험에서, 엔진이 외부 교란에 의한 압력 진동을 감쇠시켜 본래의 안정한 연소를 회복하는 경우, 그 엔진은 연소 안정 화 능력을 가지고 있다고 판정할 수 있다. 로켓엔진은, 교란의 크기를 예측하기 어려운 외부 섭동에 노출될 수 있으므로, 연소 안정화 가능 여부를 확인하는 것과 더불어 엔진이 갖고 있는 연소 안정화 성능을 정량화하여 파악하는 작업이 필요하다. 이를 위해 몇 가지 주요 인자를 도입하였고, 이를 평가하는 방법을 검토하였다. 성공적으로 완료된 KSR-III 로켓 개발과정에서 로켓엔진의 안정성 확보를 위해 6회의 안정성 평가 시험이 수행되었다. 이를 토대로, 연소 안정화 성능의 정량화 방법을 KSR-III 엔진에 적용하여 엔진의 안정화 성능을 분석하였다.

상승모근 근막동통증후군 환자에 대한 마사지, 신장운동, 견갑골 안정화운동의 효과 비교 (Comparison of the Effects of Massage, Stretching Exercise and Scapular Stabilization Exercise in Patients with Upper Trapezius Myofascial Pain Syndrome)

  • 박영석;김선엽;오덕원;최종덕;배호원;서영주
    • 대한정형도수물리치료학회지
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    • 제17권1호
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    • pp.1-8
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    • 2011
  • Background: The purpose of this study was to determine the effects of massage, stretching exercise, and scapular stabilization exercise in patients with upper trapezius myofascial pain syndrome (MPS). Methods: Twenty-three female patients with upper trapezius MPS were randomly allocated to three groups: massage, stretching exercise, and scapular stability exercise groups. Therapeutic intervention for all groups included general therapy such as hot pack, transcutaneous electrical nerve stimulation and ultrasound. Patients in the massage group (n=8), stretching group (n=7), and stabilization exercise group (n=8) received their respective therapy program after general therapy for 15 minutes. Therapeutic intervention for each group was performed three times per week for six weeks. All groups were tested four times: prior to the test, at three weeks, at six weeks, and at nine weeks. Results: Pain levels decreased significantly in the stretching and stabilization exercise groups over time (p<.05). The rate of change in pain level was significantly different among all groups (p<.01), and the stability exercise group experienced the lowest pain level. Pressure-pain level increased significantly in the stabilization exercise group over time (p<.05). The rate of change in pressure-pain level was significantly different among all groups (p<.01), and the stability exercise group had the highest pressure-pain level. The level of upper-extremity stability increased significantly in the stability exercise group over time (p<.05). The rate of change in the upper-extremity stabilization level was significantly different among all groups (p<.01), and the stability exercise group had the highest upper-extremity stability level. Conclusions: Scapular stabilization exercises proved to be the most effective therapy for MPS patients.

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액체 로켓엔진의 연소 안정성 평가 (Stability Rating of Liquid Propellant Rocket Engine)

  • 손채훈;김영목
    • 한국추진공학회:학술대회논문집
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    • 한국추진공학회 2003년도 제21회 추계학술대회 논문집
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    • pp.73-77
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    • 2003
  • 액체 로켓엔진 개발과정에서 수행되는 여러 가지 시험 중 연소 안정성 평가 시험을 통해, KSR-III 로켓엔진의 연소 안정성을 평가하였다. 안정성 평가시험에서, 엔진이 외부 교란에 의한 압력 진통을 감쇠시켜 본래의 안정한 연소로 회복되는 경우, 그 엔진은 연소 안정화 능력을 가지고 있다고 판정할 수 있다. 로켓엔진은, 교란의 크기를 예측하기 어려운 외부 섭동에 노출될 수 있으므로, 엔진의 연소 안정화 가능 여부를 확인하는 것과 더불어 엔진이 갖고 있는 연소 안정화 능력을 정량화하여 파악하는 작업이 필요하다. 이를 위해 몇 가지 인자를 도입하였고, 이를 평가하는 방법을 검토하였다. 성공적으로 완료된 KSR-III 로켓개발과정에서 로켓엔진의 안정성 확보를 위해 5회의 안정성 평가 시험이 수행되었다. 이를 토대로, 앞서 언급한 안정화 능력의 정량화 방법을 KSR-III 엔진에 적용하여 그 엔진의 안정화 성능을 분석하였다.

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Stabilization of pressure solutions in four-node quadrilateral elements

  • Lee, Sang-Ho;Kim, Sang-Hyo
    • Structural Engineering and Mechanics
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    • 제6권6호
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    • pp.711-725
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    • 1998
  • Mixed finite element formulations for incompressible materials show pressure oscillations or pressure modes in four-node quadrilateral elements. The criterion for the stability in the pressure solution is the so-called Babu$\check{s}$ka-Brezzi stability condition, and the four-node elements based on mixed variational principles do not appear to satisfy this condition. In this study, a pressure continuity residual based on the pressure discontinuity at element edges proposed by Hughes and Franca is used to study the stabilization of pressure solutions in bilinear displacement-constant pressure four-node quadrilateral elements. Also, a solid mechanics problem is presented by which the stability of mixed elements can be studied. It is shown that the pressure solutions, although stable, are shown to exhibit sensitivity to the stabilization parameters.

A Stabilization algorithm for Fuzzy Systems with Singleton Consequents

  • Michio Sugeno;Lee, Chang-Hoon
    • 한국지능시스템학회:학술대회논문집
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    • 한국퍼지및지능시스템학회 1998년도 The Third Asian Fuzzy Systems Symposium
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    • pp.36-41
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    • 1998
  • This paper presents a stabilization algorithm for a class of fuzzy systems with singleton consequect. To this aim, we introduce two canonical forms of an unforced fuzzy system and a stability theorem. A design example is shown to verify the stabilization algorithm.

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LFG 혼합 연료의 화염 안정화 특성 (Characteristics of Flame Stabilization of the LFG Mixing Gas)

  • 김선호;오창보;이창언;이인대
    • 한국연소학회:학술대회논문집
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    • 한국연소학회 1999년도 제19회 KOSCO SYMPOSIUM 논문집
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    • pp.165-172
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    • 1999
  • Landfill gas has merely half heating value compared with liquified natural gas but can be greatly utilized as a commercial fuel. The authors have examined emission characteristics as well as measured burning velocity of LFG mixed gas which contains plenty of $CO_{2}$. With the viewpoint of fuel utilization, flame stability could be one of important characteristics of LFG. In this study, the comparison experiments are conducted between $CH_{4}$ and LFG for searching the region of flame stabilization based upon the flame blowout at maximum fuel stream velocity. As a result, it is found that stabilization region of LFG is not improved with that of $CH_{4}$ in non-swirl/or weak swirl jet diffusion flame. However, it is also known that flame stability is hardly affected by inert gas in the strong swirl with considering widened flame stabilization region of LFG rather than LNG.

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요통의 요골반부 안정화(lumbo-pelvic stabilization) 접근법 (Lumbo-pelvic stabilization approach for lower back dysfunction)

  • 김선엽
    • 대한정형도수물리치료학회지
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    • 제4권1호
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    • pp.7-20
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    • 1998
  • Activity of the trunk muscles is essential for maintaining stability of the lumbar spine because of the unstable structure of that portion of the spine. The central nervous system deals with stabilization of the spine by contraction of the abdominal and multifidus muscles in anticipations of reactive forces produced by limb movement. Recent evidence indicates that the lumbar multifidus muscle and transversus abdominis muscle may be involved in controlling spinal stability. Stabilization training in neutral spine is an integrated approach of education in proper posture and body mechanics along with exercise to improve strength, flexibility, muscular and cardiovascular endurance, and coordination of movement.

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Robust D-Stability and D-Stabilization of Dynamic Interval Systems

  • Mao, Wei-Jie;Chu, Jian
    • International Journal of Control, Automation, and Systems
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    • 제5권5호
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    • pp.594-600
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    • 2007
  • A sufficient condition for the robust D-stability of dynamic interval systems is proposed in this paper. This D-stability condition is based on a parameter-dependent Lyapunov function obtained from the feasibility of a set of matrix inequalities defined at a series of partial-vertex-based interval matrices other than the total vertex matrices as previous results. This condition is also extended to the robust D-stabilization problem of dynamic interval systems, which supplies an effective synthesis procedure for any LMI D-region. The proposed conditions can be simplified to a set of LMIs, which can be solved by efficient interior point methods in polynomial time.

비압축성 물체의 수치해 안정화 기법 (A Pressure Stabilization Technique for Incompressible Materials)

  • Lee, Sang-Ho;Kim, Sang-Hyo
    • 한국전산구조공학회:학술대회논문집
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    • 한국전산구조공학회 1995년도 가을 학술발표회 논문집
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    • pp.153-160
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    • 1995
  • Mixed finite element formulations for incompressible materials show pressure oscillations or pressure modes in four-node quadrilateral elements. The criterion for the stability in the pressure solution is the so-called Babufka-Brezzi stability condition, and the four-node elements based on mixed variational principles do not appear to satisfy this condition. In this study, a pressure continuity residual based on the pressure discontinuity at element edges is used to study the stabilization of pressure solutions in bilinear displacement-constant pressure four-node quadrilateral elements. It is shown that the pressure solutions, although stable, exhibit sensitivity to the stabilization parameters.

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