• Title/Summary/Keyword: Stablility

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ON STABILITY OF A QUADRATIC FUNCTIONAL EQUATION

  • Jun, Kil-Woung;Kim, Hark-Mann;Lee, Don O
    • Journal of the Chungcheong Mathematical Society
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    • v.15 no.2
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    • pp.73-84
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    • 2003
  • In this paper, we investigate the new quadratic type functional equation f(2x + y) - f(x + 2y) = 3f(x) - 3f(y) and prove the stablility of this equation in the spirit of Hyers, Ulam, Rassias and G$\breve{a}$vruţa.

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Equivalent Physical Damping Parameter Estimation for Stable Haptic Interaction (안정적인 햅틱 상호작용을 위한 등가 물리적 댐핑 추정)

  • Kim, Jong-Phil;Seo, Chang-Hhoon;Ryu, Je-Ha
    • The Journal of Korea Robotics Society
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    • v.1 no.2
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    • pp.135-141
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    • 2006
  • This paper presents offline estimation of equivalent physical damping parameter in haptic interaction systems where damping is the most important parameter for stability. Based on the previous energy bounding algorithm, an offline procedure is developed in order to estimate the physical damping parameter of a haptic device by measuring energy flow-in to the haptic device. The proposed method does not use force/torque sensor at the handgrip. Numerical simulation and experiments verified effectiveness of the proposed method.

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A comparative study on slope stability by program and stability cahrt (프로그램과 도표에 의한 사면안정해석의 비교연구)

  • Ju, Gyeong-Hun;Kim, Ju-Cheol;Lee, Jong-Gyu
    • Proceedings of the Korean Geotechical Society Conference
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    • 1994.09a
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    • pp.253-258
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    • 1994
  • Recently, computer technique for the analysis of slope stability enable to reduce a considerable time and efforts. And also, stability problems can be approached by using stablility chart which was basically developed to handle the problems under simple conditions only. Most of the conventional slope stability computer programs and stability chart are still based on the general limit equilibrium method. 16 types of sample slopes and 2 types of failure slope were compared and analysed by stability charts and programs. This research work intend to apply 4 types of conventional computer programs based on the same theoretical backgroung and 7 types of stability charts for solving the same stability problems and the results and compared and analysed in order to justify their reliability.

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Stablility Analysis of Underground Cold Storage Openings in Shallow Jointed Rocks (천심도 절리 암반 중에 굴착된 지하 냉장저장 공동의 안정성 해석)

  • 김호영;박연준;한공창;박의섭;선경건
    • Tunnel and Underground Space
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    • v.7 no.1
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    • pp.58-64
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    • 1997
  • A pilot plant of underground cold storage for food has been excavated as a R&D program. For the stability assessment of underground cold storage opeinengs in shallow jointed rocks, three kinds of stability problems were analyzed by numerical methods. For the analysis of unstability by rock block movements, DEM was used considering the statistical distribution of rock joints. Concerning thermally induced cracking, FDM was used with thermomechanical stress analysis. Finally, in order to evaluate the joint failure during the thawing process, BE algorithm was applied. Numerical examples applied for the pilot plant show that the possibility of unstable failure of opeings exists but can be avoided with proper rock reinforcements provided.

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Development Of Small Signal Stablility Linear Analysis Program for Large Scale Power System. (대규모 전력계통의 미소신호 안정도 해석을 위한 선형해석 프로그램 개발)

  • Song, Sung-Geun;Nam, Ha-Kon;Shim, Kwan-Shik;Kim, Yong-Gu;Kim, Dong-Joon
    • Proceedings of the KIEE Conference
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    • 1999.07c
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    • pp.1054-1056
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    • 1999
  • It is the most important in small signal stability analysis of large scale Power systems to compute only the dominant eigenvalues selectively with numerical stability and efficiency. In this Paper evoluted linear analysis program, transformed state matrix using Inverse transformation with complex shift and then Hessenberg process and iterative scheme are used to accelerate Hessenberg process, can calculate dominant eigenvalues. In this Paper, The accuracy of this Program has been validated against 4-machines 11-bus system and New England 10-machines 39-bus system. Also applied to KEPCO system - about 791-bus 250-machines 2500-branches, got 2568 order state matrix, and calculated two dominant modes. This analysis result equaled to result of EPRI's SSSP program to use commonly, and calculating time is faster.

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The Effects of Mean-Line Shape on Longitudinal Stablility of a Wing in Ground Effect

  • Kim, Wu-Joan;Shin, Myung-Soo
    • Journal of Hydrospace Technology
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    • v.2 no.2
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    • pp.14-23
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    • 1996
  • The Reynolds-averaged Navier-Stokes equations for turbulent flow around a two-dimensional foil section moving ova. a flat surface (roller plate) is solved. The numerical method utilized the finite-difference schemes in collocated grids and the Baldwin-Lomax model is employed for turbulence closure. Calculations are carried out for three foil sections of different mean-line shape with various height ratio. As a foil approaches the bottom surface, the lift is augmented, while there exist some differences in pitching moment due to mean-line shape. It was found that the S-shaped mean line deteriorates lift characteristics but increases pitching moment to restore the designed height.

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Arthrodesis of the Knee with Vascularized Fibular Graft - A Case of Infected Total Knee Arthroplasty - (혈관 부착 비골 전위술을 이용한 슬관절 유합술 - 슬관절 전치환술 후 감염이 합병된 증례 -)

  • Chung, Duke-Whan;Han, Chung-Soo;Lee, Jae-Hoon;Jeong, Sun-Teak;Park, Jin-Sung
    • Archives of Reconstructive Microsurgery
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    • v.15 no.2
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    • pp.111-116
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    • 2006
  • An infection after total knee arthroplasty has many complications such as severe bone defect, skin and soft tissue problems, devastated general condition, so arthrodesis is preferred as treatment option. However, poor bony contact due to severe bone defect and inadequate conditions of the soft tissue often cause nonunion or severe limb shortening after arthrodesis. More over these conditions, it is not easy to choose appropriate fixative devices. In these situations, the arthrodesis using vascularized fibular graft can be the solution. Vascularized fibular graft (VFG) can playa role as a suitable material for the treatment of bone defects. And VFG can overcome poor blood circulation caused by scar tissues, and can be relatively more durable and adequate length. In the long term, VFG can be hypertrophied by weight bearing, and will give mechanical stablility. The purpose of the paper is to report the successful results of arthrodesis using VFG in a patient who got extensive bone defect after failed revision total knee arthroplasty with infection.

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Operation Characteristics of 5 kW Class Proton-Exchange-Membrane Fuel Cell(PEMFC) Stack (5 kW급 고분자 전해질 연료전지 스택의 운전 특성)

  • Kim, Jae-Dong;Lee, Jung-Woon;Park, Dal-Ryung
    • Journal of the Korean Institute of Gas
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    • v.11 no.1 s.34
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    • pp.51-54
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    • 2007
  • 78-cell proton exchange membrane fuel cell(PEMFC) stack with an effective electrode area of $295cm^{2}$ were investigated its operational characteristics and effects of CO poisoning. When power output, 5.4 kW, was released at current density of $325mA/cm^{2}$ for 6 hours, stablility of each cell was showed the small deviation of 2.3%. Carbon monoxide is a conventional contaminant in the fuel obtained from reforming processes with an important influence on the performance of the PEMFC. The studies of continuous injection of CO presented (5-20 ppm) with the time gave information about poisoning and recovery processes of the stack.

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Kinetic Analysis on the Lumbar at the Trunk Flexion according to the Degree of Hamstring Flexibility of Healthy Adult (정상 성인의 슬괵근 유연성 정도에 따른 체간 굴곡시 요추의 운동학적 분석)

  • Kim, Gi-Chul;Hwang, Bo-Gak
    • Journal of the Korean Society of Physical Medicine
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    • v.7 no.4
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    • pp.501-507
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    • 2012
  • PURPOSE: This study aims to examine the effects of trunk flexion on the kinetic characteristics of the lumbar according to the degree of hamstring flexibility. METHODS: This study has as its subjects 29 young adults and divides them into the group (NSRTG, n=15) with the normal length of hamstrings according to SRT and the group (SSRTG, n=14) tending to have shortened hamstrings. Sit and Reach Test was conducted to evaluate the degree of hamstring flexibility. And to examine the kinetic difference of the lumbar at the trunk flexion, it was compared and analyzed by using the picture archiving and communication system (PACS). RESULTS: SSRTG showed more significant difference than NSRTG in the analysis on the trunk flexion of NSRTG and SSRTG. CONCLUSION: According to the analysis, the shortening of hamstrings is the factor that affects the dynamic stability of the lower lumbar through the reduction of the pelvic anterior tilt at the trunk flexion.