• Title/Summary/Keyword: Linear formula

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Differences in Perception of Continuing Education by Academic Background with Physical Therapists

  • Kim, Kijong;Kim, Juhong
    • Journal of The Korean Society of Integrative Medicine
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    • v.8 no.3
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    • pp.63-69
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    • 2020
  • Purpose : Various research studies are needed to raise the perception of the CE of Korean physical therapists. However, there are little studies have been conducted, and relatively few studies are available to read on online. The purpose of the study is to find out the differences in the perception of CE according to the physical therapist's academic background. In this way, this article intends to strengthen the perception of the CE of health-care workers, such as physical therapists and occupational therapists in the Republic of Korea so that contributing to the development of national health. Methods : Present study showed that 431 out of 563 people who participated in the two meetings of CE conducted by the Gwangju Metropolitan City of the Korea Physical Therapy Association responded in the survey in 2015. Among them, only 238 people were surveyed on the awareness of CE in 2014, excluding 181 questionnaires due to poor responses and 112 questionnaires that did not participate in CE in the previous year. Descriptive analyses were conducted to identify the perception among those who experienced CE, and simple linear regression analysis was performed using dummy variables to identify awareness of the education based on their academic background. Results : Question 3 (p=.000, R2=.067) was significant in the significance test of the regression equation for perception of the CE (p<.05). Question 1 (p=.687), 2 (p=.066), 4 (p=.430), 5 (p=.085), and 6 (p=.054), 7 (p=.111), 8 (p=.088), 9 (p=.213), 10 (p=.191) and 11 (p=. 169), the regression formula was not significant (p>.05). Conclusion : Physical therapists had a moderate perception of the need for a CE and had the idea that improvements were required in what was provided in that education. In addition, there was no statistically significant difference, although there was a greater awareness of CE in the Master of Science Course or higher than college or university graduates.

The Quantification of TiO2 Thickness Using Color Values by Spectrophotometer and Chromameter (분광측색계, 색차계의 색 수치 값을 이용한 타이타늄 산화막의 두께 정량화)

  • Lee, Dayoung;Han, Ayoung;Ha, Dongheun;Yoo, Hyeonseok;Kim, Hunsik;Jung, Nagyeom;Jang, Kwanseop;Choi, Jinsub
    • Journal of the Korean institute of surface engineering
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    • v.51 no.3
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    • pp.157-163
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    • 2018
  • The anodic $TiO_2$ layers which are prepared in various anodization conditions exhibit their specific color depending on the thickness of $TiO_2$. In this study, the relationship between the color of $TiO_2$ layer, which is grown by PEO (Plasma electrolytic oxidation), and the thickness of the $TiO_2$ layer is investigated. To evaluate the color change of the $TiO_2$ layer, the value of color ($dE^*ab$) is measured and calculated by spectrophotometer and chromameter. As a result, it is found that $dE^*ab$ values and thickness of $TiO_2$ layers form a linear relationship with meaningful formular. This formula can be helpful to quantify the thickness of the $TiO_2$ layer by the numerical $dE^*ab$ values. In this process, the spectrophotometer shows more precise results than the chromameter dose. If fluoride ions ($F^-$) are included in the electrolyte, it will affect the $dE^*ab$ values of the $TiO_2$. layer. This is against the propensity, which is analyzed by XRD (X-ray diffraction) and XPS (X-ray photoelectron spectroscopy). It is important that the formular suggested in this study provides other metals which can be also anodized with the possibility of quantifying the thickness of the $TiO_2$ layer by the $dE^*ab$ values.

Analysis of Large-Amplitude Ship Motions Using a Cartesian-Gridbased Computational Method (직교격자 기반 수치기법을 이용한 선박의 대변위 운동해석)

  • Yang, Kyung-Kyu;Nam, Bo-Woo;Lee, Jae-Hoon;Kim, Yonghwan
    • Journal of the Society of Naval Architects of Korea
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    • v.49 no.6
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    • pp.461-468
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    • 2012
  • In this study, a Cartesian-grid method based on finite volume approach is applied to simulate the ship motions in large amplitude waves. Fractional step method is applied for pressure-velocity coupling and TVD limiter is used to interpolate the cell face value for the discretization of convective term. Water, air, and solid phases are identified by using the concept of volume-fraction function for each phase. In order to capture the interface between air and water, the tangent of hyperbola for interface capturing (THINC) scheme is used with weighed line interface calculation (WLIC) method which considers multidimensional information. The volume fraction of solid body embedded in the Cartesian grid system is calculated using a level-set based algorithm, and the body boundary condition is imposed by a volume weighted formula. Numerical simulations for the two-dimensional barge type model and Wigley hull in linear waves have been carried out to validate the newly developed code. To demonstrate the applicability for highly nonlinear wave-body interactions such as green water on the deck, numerical analysis on the large-amplitude motion of S175 containership is conducted and all computational results are compared with experimental data.

Evaluation on Flexural Performance of Precast Decks with Ribbed Joint by FEM (유한요소해석에 의한 요철형 이음단면을 갖는 프리캐스트 바닥판의 휨성능 평가)

  • Oh, Hyun-Chul;Chung, Chul-Hun;Kang, Myoung-Gu;Park, Se-Jin;Shin, Dong-Ho
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.20 no.1
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    • pp.85-94
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    • 2016
  • In this study, a non-linear FEM model is presented to predict the static flexural performance of precast bridge decks with ribbed joint and is verified with previous experiment results through comparison. The several theory of material properties were applied to each mechanical properties in FEM model and FEM model's input variables were determined through experiment result and parametric study. The FEM results showed good accuracy in predicting the structural performance of the specimens and FEM model's average error rate was 5%. Also, each specimen's cracking aspect and failure mode can be predicted through FEM's plastic strain distribution. Thus, this FEM model can be used effectively for predicting the ultimate behavior and parametric study to development of design formula for joint.

Determination of stay cable force based on effective vibration length accurately estimated from multiple measurements

  • Chen, Chien-Chou;Wu, Wen-Hwa;Huang, Chin-Hui;Lai, Gwolong
    • Smart Structures and Systems
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    • v.11 no.4
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    • pp.411-433
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    • 2013
  • Due to its easy operation and wide applicability, the ambient vibration method is commonly adopted to determine the cable force by first identifying the cable frequencies from the vibration signals. With given vibration length and flexural rigidity, an analytical or empirical formula is then used with these cable frequencies to calculate the cable force. It is, however, usually difficult to decide the two required parameters, especially the vibration length due to uncertain boundary constraints. To tackle this problem, a new concept of combining the modal frequencies and mode shape ratios is fully explored in this study for developing an accurate method merely based on ambient vibration measurements. A simply supported beam model with an axial tension is adopted and the effective vibration length of cable is then independently determined based on the mode shape ratios identified from the synchronized measurements. With the effective vibration length obtained and the identified modal frequencies, the cable force and flexural rigidity can then be solved using simple linear regression techniques. The feasibility and accuracy of the proposed method is extensively verified with demonstrative numerical examples and actual applications to different cable-stayed bridges. Furthermore, several important issues in engineering practice such as the number of sensors and selection of modes are also thoroughly investigated.

Shear capacity of stud shear connectors with initial damage: Experiment, FEM model and theoretical formulation

  • Qi, Jianan;Wang, Jingquan;Li, Ming;Chen, Leilei
    • Steel and Composite Structures
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    • v.25 no.1
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    • pp.79-92
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    • 2017
  • Initial damage to a stud due to corrosion, fatigue, unexpected overloading, a weld defect or other factors could degrade the shear capacity of the stud. Based on typical push-out tests, a FEM model and theoretical formulations were proposed in this study. Six specimens with the same geometric dimensions were tested to investigate the effect of the damage degree and location on the static behavior and shear capacity of stud shear connectors. The test results indicated that a reduction of up to 36.6% and 62.9% of the section area of the shank could result in a dropping rate of 7.9% and 57.2%, respectively, compared to the standard specimen shear capacity. Numerical analysis was performed to simulate the push-out test and validated against test results. A parametrical study was performed to further investigate the damage degree and location on the shear capacity of studs based on the proposed numerical model. It was demonstrated that the shear capacity was not sensitive to the damage degree when the damage section was located at 0.5d, where d is the shank diameter, from the stud root, even if the stud had a significant reduction in area. Finally, a theoretical formula with a reduction factor K was proposed to consider the reduction of the shear capacity due to the presence of initial damage. Calculating K was accomplished in two ways: a linear relationship and a square relationship with the damage degree corresponding to the shear capacity dominated by the section area and the nominal diameter of the damaged stud. This coefficient was applied using Eurocode 4, AASHTO LRFD (2014) and GB50017-2003 (2003) and compared with the test results found in the literature. It was found that the proposed method produced good predictions of the shear capacity of stud shear connectors with initial damage.

Phonon Scattering and Impact ionization for Silicon using Full Band Model at 77K (풀밴드 모델을 이용한 77K Si의 포논산란 및 임팩트이온화에 관한 연구)

  • 유창관;고석웅;정학기;이종인
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 1999.11a
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    • pp.552-554
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    • 1999
  • Phonon scattering and impact ionization models have been presented to analyze hot carrier transport in high energy region, using full band model and Fermi's golden rule. We have investigated temperature dependent properties for impact ionization process of Si using realistic energy band structures at 77K and look. The realistic full band model, obtained from the empirical pseudopotential method with local from factors, is used to calculate scattering rate. The accurate calculation of impact ionization rate requires the use of a wavevector- and frequency-dependent dielectric function ξ ( q,$\omega$). The empirical phonon scattering rate P$\sub$ph/, is given by deriving from linear function for P$\sub$ph/ versus D(E) since the phonon scattering rate is linearly depended on density of states D(E). Impact ionization rate p,, is calculated from the first principle's theory. and fitted by modified Keldysh formula having power of above 2.

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A Study on the Strength Evaluation of Rectangular Steel Tubular Columns Infilled with High Strength Concrete (고강도콘크리트 충전 각형강관기둥의 내력평가에 관한 연구)

  • Shim, Jong Seok;Han, Duck Jeon
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.15 no.1
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    • pp.95-102
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    • 2011
  • The CFT columns used in thin-walled steel tubes can be more economical, because it was expected the increase of strength by restriction for the local buckling of steel tubes. The purpose of this paper is to review feasibility of existing design formula and verify the applicability limit of width-to-thickness ratio for increasing the strength of rectangular CFT columns. As the main parameters of experiments, width-to-thickness ratios of steel tube, height of rectangular concrete columns, and concrete filled or not. The strength of concrete are selected to 90MPa. From the test results, the confinement effect of steel tube on the compressive strength of infilled concrete is remarkably appeared in the thin-walled rectangular steel tube columns infilled wih high strength concrete. By the non-linear analysis, the axial strength from experiment result was given higher than analysis result for all CFT stub columns.

The Relationship of Contained Water and Coloring Rate of Thiamine Monosalts in Preparations as an Additive of Food and Formula Feed (식품 및 배합사료의 첨가제로서 치아민 모노염류의 함수량과 착색도)

  • Park, Hong-Koo
    • Applied Biological Chemistry
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    • v.40 no.5
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    • pp.409-415
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    • 1997
  • In order to find out the relationship between contained water and coloring rate of thiamine monosalts in preparations, three kinds of thiamine monorhodanate, -monoiodide, -monobromide were manufactured and investigated as powders, granules and compressed tablets, respectively. Apparent coloring rate constants and solubility in accordance with temperature changes were measured. Nature of contained water and coloration of thiamine monosalts in preparations was examined in detail. It was thereby found that if water attached in a free state, coloration occured whose degree was approximately proportional to the quantity of such water, and a linear relation was found to hold between the logarithm of the apparent coloring rate constants and the reciprocal of the absolute temperature in granules and compressed tablets.

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Nonlinear Seismic Analysis of Steel Buildings Considering the Stiffnesses of the Foundation-Soil System (기초지반강성을 고려한 철골 건축구조물의 비선형 지진해석)

  • Oh, Yeong Hui;Kim, Yong Seok
    • Journal of Korean Society of Steel Construction
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    • v.18 no.2
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    • pp.173-180
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    • 2006
  • The seismic responses of a building are affected by the base soil conditions. In this study, linear time-history seismic analysis and nonlinear pushover static seismic analysis were performed to estimate the base shear forces of 3-, 5-, and 7-story steel buildings, considering the rigid and soft soil conditions. Foundation soil stiffness, based on the equivalent static stiffness formula, is used for the damper, one of the Link elements in SAP 2000. The base shear forces of the steel buildings, estimated through time-history analysis using the general-purpose structural-analysis program of SAP 2000, were compared with those calculated using the domestic seismic design code, the UBC-97 design response spectrum. and pushover static nonlinear analysis. The steel buildings designed for gravity and wind loads showed elastic responses with a moderate earthquake of 0.11 g, while the elastic soft-soil layer increased the displacement and the base shear force of the buildings due to soil-structure interaction and soil amplification. Therefore, considering the characteristics of the soft-soil layer, it is more reasonable to perform an elastic seismic analysis of a building's structure during weak or moderate earthquakes.