• Title/Summary/Keyword: static measurements

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Reliability of static balance abilities measure using a smartphone's acceleration sensor (스마트폰의 가속도 센서를 이용한 정적균형능력 측정의 신뢰도 연구)

  • Han, Seul-Ki;Lee, In-Hak;Park, Nu-Ri
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.6
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    • pp.233-238
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    • 2016
  • The purpose of this study is to investigate the reliability of static balance measurements using a smartphone. Thirty subjects were selected among university students who had no fractures, history of operation, or inflammatory arthritis, and they had not started regular exercise during the past three months. The smartphone used in this study was a Galaxy S5LTE (SM-G900F, Samsung, Korea, 2014), and the application was a Sensor Kinetics Pro (Ver. 2.1.2, INNOVENTIONS Inc., US, 2015). Static balance ability was measured three times at one-day intervals between tests and retests. The first and second measurements used the same process. Analysis was done using the Wilcoxon signed rank test and intraclass correlation coefficient (ICC (2,1)). The results were as follows. With eyes opened, there was no significant difference (p>0.05), a high volume of correlation (r>0.75, p<0.05), and very high reliability (ICC>0.80) between the first measurement and second measurement. With eyes closed, there was also no significant difference (p>0.05), a high volume of correlation (r>0.75, p<0.05), and very high reliability (ICC>0.80) between the measurements. The results show that the smartphone is likely accurate for measuring static balance. This study will look forward to being the only basis for measuring future application development and the ability to balance.

Structural identification of Humber Bridge for performance prognosis

  • Rahbari, R.;Niu, J.;Brownjohn, J.M.W.;Koo, K.Y.
    • Smart Structures and Systems
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    • v.15 no.3
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    • pp.665-682
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    • 2015
  • Structural identification or St-Id is 'the parametric correlation of structural response characteristics predicted by a mathematical model with analogous characteristics derived from experimental measurements'. This paper describes a St-Id exercise on Humber Bridge that adopted a novel two-stage approach to first calibrate and then validate a mathematical model. This model was then used to predict effects of wind and temperature loads on global static deformation that would be practically impossible to observe. The first stage of the process was an ambient vibration survey in 2008 that used operational modal analysis to estimate a set of modes classified as vertical, torsional or lateral. In the more recent second stage a finite element model (FEM) was developed with an appropriate level of refinement to provide a corresponding set of modal properties. A series of manual adjustments to modal parameters such as cable tension and bearing stiffness resulted in a FEM that produced excellent correspondence for vertical and torsional modes, along with correspondence for the lower frequency lateral modes. In the third stage traffic, wind and temperature data along with deformation measurements from a sparse structural health monitoring system installed in 2011 were compared with equivalent predictions from the partially validated FEM. The match of static response between FEM and SHM data proved good enough for the FEM to be used to predict the un-measurable global deformed shape of the bridge due to vehicle and temperature effects but the FEM had limited capability to reproduce static effects of wind. In addition the FEM was used to show internal forces due to a heavy vehicle to to estimate the worst-case bearing movements under extreme combinations of wind, traffic and temperature loads. The paper shows that in this case, but with limitations, such a two-stage FEM calibration/validation process can be an effective tool for performance prognosis.

A Study of Static Pressure Differential Measurement of Nozzle for Miniaturization of a Air Flow Meter (풍량 측정 장치 소형화를 위한 노즐 정압차 측정 연구)

  • Oh, Sang-Teak;Kim, Young Il;Chung, Kwang-Seop
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.28 no.10
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    • pp.414-419
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    • 2016
  • Air flow measurement is a fundamental and important task for testing, adjusting, and balancing of HVAC system. However, it is difficult to carry out in the field due to the large size and weight of the flow meter. In this study, for the purpose of developing a small and portable flow meter, we proposed a different method of static pressure measurement and verified it experimentally. In the proposed method, static pressure difference was measured by inserting a tube inside the chamber before and after the nozzles. The results were compared with measurements according to the ANSI/ASHRAE standard. The results were in good agreement, indicating that the inserted tube method could be used for static pressure measurement of a portable flow meter. The proposed method eliminates the pressure tubes that are attached outside, which results in smaller size and easy handling.

The Effect of TOGU Exercise on the Postural Balance and Foot Pressure Distribution (토구 운동이 자세균형과 족저압 분포에 미치는 영향)

  • Kim, Soon-Ja;Lee, Kwang-Jae
    • Journal of Korean Physical Therapy Science
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    • v.19 no.1
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    • pp.9-15
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    • 2012
  • Background : The purpose of this study to find the Effect of TOGU Exercise on the Postural Balance and Foot Pressure Distribution. Methods : Four male and five female subjects last one year and no damage at all, even unique Foot skin diseases or orthopedic surgical disease who are not selected and applied before and after exercise TOGU and Foot Pressure Distribution of static equilibrium and measured using were compared. Results : After exercise conducted TOGU. right and life the static balance measurements of the height difference between the two sides of the acromion before exercise to 0.8cm and 1.4cm reduction in the movement, and also before and after the static balance measured sagittal the lateral tibial line drawn straight down from the earlobe and vertical slit in the distance before exercise from 5.8cm to 3.4cm decreased after exercise before and after the balance has also improved significantly(p<.05). Static balance of the body, according to the pressure of the foot in the exercise before/after there was no significant difference(p>.05). Conclusion : Dynamic shaking of the body have a positive impact on the static equilibrium could know that.

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The Comparison of Clinical Assessment Tools for the Foot Posture

  • Lee, Jin-Yi;Choi, Jong-Duk
    • Physical Therapy Korea
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    • v.19 no.3
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    • pp.115-123
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    • 2012
  • It is important to assess foot posture when investigating the relationship between lower extremity dysfunctions and foot types. Although several measurements of static foot posture have been used, there is no consensus regarding clinical measurements for foot posture. The aim of this study is to explore the differences among navicular drift (NDt), foot posture index (FPI), arch index (AI), dorsal arch height ratio (DAHR), normal navicular height truncated (NNHt) and to discover the most effective measurement. After foot types were classified by navicular drop test (NDp), clinical measurements of NDt, FPI, AI, DAHR, and NNHt were performed on 64 subjects' feet. ANOVA analysis was used for the variance of the difference between the NDp and the five kinds of clinical measurements, and the level of significance was set at ${\alpha}$=.05. The results showed that all five clinical measurements demonstrated significant differences with navicular drop. In post-hoc, FPI and NNHt showed significant differences in all foot types. The five clinical measurements are suitable the classification of foot types through the NDp. Therefore, it could be possible to assess correct and objective foot posture by using FPI and NNHt.

Changes in Body Surface Lines Caused By Lower Limb Movements in Designing Slacks (I) (슬랙스 설계를 위한 하지동작에 따른 체표선 변화 1)

  • Cho Sung-Hee
    • Korean Journal of Human Ecology
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    • v.7 no.3
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    • pp.15-33
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    • 2004
  • A precise understanding of the human form in static pose serves as the basis of designing clothing. When the human body is in motion, however, even an article of clothing designed to fit the human form in static pose can pull and change, thus restricting the body. In order to increase the fit of the clothing, which may be termed the second skin, its form and measurements therefore must be determined in correlation not only with the formal characteristics of the human body, in static pose but also with its functional characteristics in motion, as caused by the movements of the human body. In this study, the motion factor was selected as the primary basis for designing slacks with good fit in both static and moving states. By indentifying the areas in which lower limb movement cause significant changes in body surface lines, we suggest several application methods for designing slacks. Using unmarried female university students aged 18 - 24 as subjects, a total of 32 body surface categories (15 body surface lines and 17 body surface segment lines) were measured in one static and 9 movement poses. In particular, expansion and contraction levels and rates were measured and used in the analysis. The analysis first involved the calculation of the average measurement per body part in body surface line in static pose as well as of the average expansion and contraction levels and rates in 9 lower limb movements. Two-way MANOVA and multiple comparison analysis (Tukey) were conducted on movements and individual somatotypes regarding measurement per body part and expansion and contraction rates. Body parts whose measurements of body surface lines differed significantly in body surface line in static pose versus in movement were then identified. The results of this study are as follows. First, changes in body surface lines caused by lower limb movements were significant in all body surface lines of the lower trunk, both horizontal and vertical, with the exception of abdomen girth, midway thigh girth, ankle girth, hip length, and posterior knee girth. Second, significantly expanded 10 body surface lines in moving pose were detected and illustrated in table 4. These body parts should be studied in designing or pattern designing, especially for close-fitting pants, in using stretch fabric, and in sensory evaluation of good fit during movement.

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A Study on the Structure of Turbulent Flow Fields According to the Operating Loads of Three-Dimensional Small-Size Axial Fan by Large Eddy Simulation (대규모와 모사에 의한 3차원 소형축류홴의 운전부하에 따른 난류유동장 구조에 대한 연구)

  • Kim, Jang-Kweon;Oh, Seok-Hyung
    • Journal of Power System Engineering
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    • v.19 no.5
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    • pp.80-85
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    • 2015
  • The unsteady-state, incompressible and three-dimensional large eddy simulation(LES) was carried out to analyze the structure of turbulent flow fields according to the operating loads of three-dimensional small-size axial fan(SSAF). LES shows the best prediction performance in comparison with any other Reynolds averaged Navier-Stokes(RANS) method because static pressure coefficients analysed by LES show a little bit larger than measurements including all flow coefficients. Also, it can be known that the wake of SSAF is divided into from axial flow to radial flow before and behind stall region according to the increase of static pressure through LES analysis.

Theory vs. Experiment of Static Characteristics of Contrarotating Hydrostatic Journal Bearing with Overhung-Type Loads (외팔형 하중지지 이중 반전 정압 베어링의 정특성 이론 및 실험 연구)

  • 이용복;김창호;권오관;최동훈;이강복
    • Tribology and Lubricants
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    • v.12 no.3
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    • pp.92-99
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    • 1996
  • Energy-efficient contrarotating propeller systems have been recently reviewed as one of alternative means in marine car-carrier applications. Contrarotating rotors preclude the usage of conventional plain journal bearings due to the lack of load carrying capacity. A new multi-recess hydrostatic contrarotating journal beating test facility has been designed and installed to test the static load carrying capacity. Measurements of flow rates and orbits have been investigated by testings on a overhung-type contrarotating rotor system which is supported by a hydrostatic journal bearing. Numerical results of static equilibria were compared with test results. Various contrarotating speed combinations, and supply pressure conditions were selected. The numerical predictions of orbit centers and flow rates are generally accurate.

gnetic Fields With Hysteresis Characteristics (히스테리시스 특성을 고려한 자계의 유한 요소 해석)

  • Jung, Hoon;Hong, Sun-Ki;Won, Jong-Soo
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.38 no.12
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    • pp.1033-1047
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    • 1989
  • A finite element method for the analysis of magnetic fields with hysteresis characteristics is proposed. The method employs Preisach model to describe hysteresis of magnetic material, so that even multi-branch or minor-loop characteristics can be taken into account. The problem can be considered as the analysis of a nonlinear equation where magnetization depends not only on the present value of the magnetic field but also on the past values, and the problem can be solved by the iteration method. Measurements were carried out on soft ferrite EI core for the comparison with computer solution, and good agreements were obtained. is investigated. A theoretical approach to gait study is proposed in which the static stability margins for periodic gaits are expressed in terms of the kinematic gait formula. The effects fo the stride length on static stability are analyzed and the relations between static stability and initial body configurations are examined. It is shown that the moving velocity can be increased to some extent without affecting stability margins for a given initial body configuration. Computer simulations are performed to verify the analysis.

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A combined experimental and numerical method for structural response assessment applied to cable-stayed footbridges

  • Kossakowski, Pawel G.
    • Advances in Computational Design
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    • v.2 no.3
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    • pp.143-163
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    • 2017
  • This paper presents a non-destructive testing method for estimating the structural response of cable-stayed footbridges. The approach combines field measurements with a numerical static analysis of the structure. When the experimental information concerning the structure deformations is coupled with the numerical data on the structural response, it is possible to calculate the static forces and the design tension resistance in selected structural elements, and as a result, assess the condition of the entire structure. The paper discusses the method assumptions and provides an example of the use of the procedure to assess the load-carrying capacity of a real steel footbridge. The proposed method can be employed to assess cable-stayed structures including those made of other materials, e.g., concrete, timber or composites.