• Title/Summary/Keyword: length change

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A Study on the Movement-Fitness according to the Surface changing of Lower-Limb -On the Movements and Shapes of Lower-limb- (하복의 체표변화에 따른 동작적합성에 관한 연구 -하복동작 및 체형을 중심으로-)

  • 박영득;서영숙
    • Journal of the Korean Society of Clothing and Textiles
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    • v.20 no.2
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    • pp.257-269
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    • 1996
  • The puropose of this study was to investigate the movement-fitness according to the surface changing of lower limb The experimental items were divided into the lower limb movements (5) and body-shapes (7). This study was done by the expansion and contraction rate consideration of length, girth Also, the lower half of body shape-change on the movements and body-shapes by flat shell was done simultaneously. The summarized findings resulted from experiments and investigation are suggested as follows; First, when commpared the expansion and contraction rate of the length and girth items, the expansion rate of the back crotch length (14~20%), hip girth (10~ 21%) and knee girth (6.2~18.5%) in rabbit leap movement was the most notable among all variables considered in this experimentation. On the others hand, the front croth length (-22~-52%) contracted remarkably. And big-thigh type was the most notable on the body-shape comparision. Second, in comparision of the expansion and contraction rate of the area on the blocks, the expansion of the hip (50~200%) and knee (51~74%) block was the most remarkable. Especially, in the sit on knees movement of the hip-down type expanded 209.4%. Third, in comparision of the lower half of body shape-change, on the movements and body- shapes by the flat shell, under the influence of knee-joint and hip-joint the shape-changs of the hip and knee block was the most notable. But the shape-change of the waist, abdomen, calf, and ankle was feeble.

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Size and Aspect Ratio Effects on the Magnetic Properties of a Spin-Valve Multilayer by Computer Simulation

  • Lim, S.H.;Han, S.H.;Shin, K.H.;Kim, H.J.
    • Journal of Magnetics
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    • v.5 no.3
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    • pp.90-98
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    • 2000
  • The change in the magnetic properties of a spin-valve multilayer with the structure IrMn (9 m)/CoFe (4 nm)/Cu (2.6 nm)/CoFe (2 nm)/NiEe (6 nm) is investigated as a function of the size and the aspect ratio. At a fixed aspect ratio (the length/width ratio) of 2, the magnetostatic interactions begin to affect the magnetic properties substantially at a spin-valve length of 5 $\mum$, and, at a length of 1 $\mum$, they become even more dominant. In the case of a fixed multilayer size (2.4 $\mum$) which is indicated by the sum of the length and the width, magnetization change occurs by continuous spin-reversal and M-H loops are characterized by no or very small hysteresis at aspect ratios smaller than unity, At aspect ratios greater than unity, magnetization change occurs by spin-flip resulting in squared hysteresis loops. A very large changes in the coercivity and the bias field is observed, and these results are explained by two separate contributions to the total magnetostatic interactions: the coercivity by the self-demagnetizing field and the bias field by the interlayer magnetostatic interaction field.

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Estimation of Muscle-tendon Model Parameters Based on a Numeric Optimization (최적화기법에 의한 근육-건 모델 파라미터들의 추정)

  • Nam, Yoon-Su
    • Journal of the Korean Society for Precision Engineering
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    • v.26 no.6
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    • pp.122-130
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    • 2009
  • The analysis of human movement requires the knowledge of the Hill type muscle parameters, the muscle-tendon and moment arm length change as a function of joint angles. However, values of a subject's muscle parameters are very difficult to identify. It turns out from a sensitivity analysis that the tendon slack length and maximum muscle force are the two critical parameters among the Hill-type muscle model. Therefore, it could be claimed that the variation of the tendon slack length and maximum muscle force from the Delp's reference data will change the muscle characteristics of a subject remarkably. A numeric optimization method to search these tendon parameters specific to a subject is proposed, and the accuracy of the developed algorithm is evaluated through a numerical simulation.

Layout design of the vehicle intake system for reducing the radiated noise (토출소음 저감을 위한 차량 흡기시스템 레이아웃 설계)

  • Kim, Hoi-Jeon;Ih, Jeong-Guon
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2006.05a
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    • pp.443-446
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    • 2006
  • For the satisfaction of the high engine performance and the low radiated sound pressure simultaneously, the duct length in the vehicle intake/exhaust system should be tuned carefully in the design and development stage of a vehicle. This study was concerned about the effects of intake duct length in clean and dirty sides on the radiated sound emitted from an inlet. An index derived from the existing prediction model of radiated sound pressure was employed to determine which duct was more influential to the radiated sound. Comparing the experimental and predicted results, we found that the change of dirty-side duct length caused a larger change than that in the clean side in the radiated sound level from a tested intake system.

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Modal Vibration Characteristics of an Annular Disk Containing Evenly Spaced Narrow Radial Slots (등간격의 좁은 반경방향 슬롯을 가진 환형 박판의 고유진동 특성)

  • Lee, Hyeong-Ill
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.19 no.6
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    • pp.560-568
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    • 2009
  • Modal vibration characteristics of a thin annular disk containing narrow radial slots are studied numerically and experimentally. Existing analytical solution is examined based on these results revealing that it can not precisely predict eigenvalues of the disk with slots since it does not accurately consider change in the vibration modes and change in strain energy density distributions due to the slots. Parametric study on slot length found that distortions in the mode shape as well as changes in the corresponding natural frequencies are proportional to the slot length. Consequently, errors in the calculated eigenvalues are also proportional to the slot length and accurate data can not be obtained with existing analytical solution above a certain level of slot length. Same phenomena can be observed in both free-free disk and fixed-free disk.

Development of a Model for the Estimation of Knee Joint Moment at MVC (MVC 상태에서의 무릎관절 모멘트 추정을 위한 모델 개발)

  • Nam, Yoon-Su;Lee, Woo-Eun
    • Journal of Biomedical Engineering Research
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    • v.29 no.3
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    • pp.222-230
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    • 2008
  • This paper introduces a method of estimating the knee joint moment developed during MVC. By combining the Hill-type muscle model and analytic results on moment arm and musculotendon length change as a function of hip and knee joint angle, the knee joint moment at a specific knee joint angle during MVC is determined. Many differences between the estimated results and the experimental data are noted. It is believed that these differences originate from inaccurate information on the muscle-tendon parameters. The establishment of exact values for the subject's muscle parameters is almost impossible task. However, sensitivity analysis shows that the tendon slack length is the most critical parameter when applying the Hill-type muscle model. The effect of a change of this parameter on the muscle length force relationship is analyzed in detail.

Analysis on Lightning Overvoltage According to Lead Length of Surge Arrester for Underground Cable Outdoor Termination Protection at C/H Tower (C/H 철탑 종단접속함 보호용 피뢰기 리드선 길이에 따른 뇌과전압 분석)

  • Jung, Chae-Kyun;Kang, Ji-Won
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.65 no.2
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    • pp.257-263
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    • 2016
  • This paper describes the lightning arrester transients in cable head termination. The installation references of cable head tower and lightning arresters are firstly reviewed, then the performance of lightning arrester operation is also evaluated based on lightning overvoltage analysis by the change of grounding lead cable length. This paper finally proposes the optimal length of grounding lead cable at the cable head termination. The limited lightning current is also proposed according to the change of grounding lead cable length. The results will contribute to protecting insulation breakdown failure against lightning surge at the terminations and joints.

Precise Measurement of the change n the optical length of a fiber Fabry-Perot interferometer. (광섬유 Fabry-Perot 간섭계를 이용한 위상 변화량의 정밀 측정)

  • 김영준
    • Proceedings of the Optical Society of Korea Conference
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    • 1989.02a
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    • pp.113-118
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    • 1989
  • By using the single mode optical fiber, we fabricated Fiber-optic Fabry-Perot interferometer (FFPI). The change over a wide range in the optical path length of a FFPI is observed. The temporal movement of the interference fringes by external condition to P.Z. T) is converted to circular motion on an oscilloscope display and then recorded with a micro-computer. The two output voltages of the D/A converters are applied to X and Y terminals of oscilloscope to display circular motion on oscilloscope. Thus the direction of phase shift can be determined with observing the direction of circular motion. The variation of the optical length can be measured by calculating the angle of spot of circle with an accuracy of λ/90 wave length due to variation of temperature in this system 2.7x10-4$^{\circ}C$.

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Change of working length in curved canals by various instrumentation techniques (만곡근관에서 근관형성법에 따른 근관작업장의 변화)

  • Jo, Jeong-Im;Jin, Myoung-Uk;Kim, Young-Kyung;Kim, Sung-Kyo
    • Restorative Dentistry and Endodontics
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    • v.31 no.1
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    • pp.30-35
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    • 2006
  • To evaluate the change of working length with various instrumentation techniques in curved canals, working length and canal curvature were determined before and after canal instrumentation in buccal or mesial canals of extracted human molars. Stainless steel K-files ($MANI^{(R)}$, Matsutani Seisakusho Co. Takanezawa, Japan), nickel-titanium K-files (Naviflex $NT^{TM}$, Brassier, Savannah, USA) , $ProFile^{(R)}$, and ProTaper (Dentsply-Maillefer, Ballaigues, Switzerland) were used to prepare the canals with crown-down technique. In two hand instrumentation groups coronal flaring was made with Gates Glidden burs. Apical canals were instrumented until apical diameter had attained a size of 30. Positional relation between the tooth apex and the $\#10$ K-file tip was examined by using AutoCAD 2000 (Autodesk Corp., San Rafael. CA, USA) under a stereomicroscope before and after coronal flaring, and after apical instrumentation. Degree of canal curvature was also measured with Schneider's method in radiographs. Data of working length and canal curvature changes were statistically analyzed with one-way ANOVA and Tukey's studentized range test. Working length and canal curvature were decreased significantly in each step in all instrumentation groups. Coronal flaring using Cates Glidden burs in hand instrument groups and whole canal instrumentation using stainless steel hand K-files caused significantly more working length change than in ProFile instrumentation group (p<0.05). The result of this study demonstrates that all of the above kinds of instrumentation in curved canals cause reduction of working length and canal curvature at each instrumentation steps, and hand instrumentation causes more working length change than ProFile.

The Strength and Length Change Properties of Recycled Aggregate Concrete(RAC) by Compressive Strength Levels (압축강도 수준별 순환골재 콘크리트의 강도와 길이변화 특성)

  • Lee, Bong-Chun;Lee, Jun;Cho, Young-Keun;Jung, Sang-Hwa
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.3 no.4
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    • pp.307-312
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    • 2015
  • This paper addresses mechanical properties and length change performance of the recycled aggregate concretes(RAC) in which natural coarse was replaced by recycled coarse aggregate(RCA) by compressive strength levels(20, 35, 50 MPa). A total of 9 RAC were produced and classified into three series, each of which included three mixes designed with three compressive strength levels of 20 MPa, 35 MPa and 50 MPa and three RCA replacement ratios of 0, 50 and 100%. Physical/Mechanical properties of RAC were tested for slump test, compressive strength, and length change. The test results indicated that the workability of RC could be improved or same by RCA replacement ratios, when compared with that containing no RCA. This is probably because of the RCA shape improving the workability of RAC. Also, the test results showed that the compressive strength was decreased by 9~10% as the RCA replacement ratios increase. However, the length change ratio by the RCA replacement ratios increased regardless of compressive strength levels. At 20 MPa level, the length change ratio was 8~40% which was much higher than that of 4~17% at both 35 and 50 MPa levels. Therefore, it was considered that such admixture addition preventing dry shrinkage is required in order to improve the properties of the RAC at 20 MPa level.