• Title/Summary/Keyword: p-y curve

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An Analysis of Factors that Affect Spinal Scoliosis of College Students (일부 대학생의 척추 측만에 영향을 미치는 요인 분석)

  • Hwang, Hyun-Sook
    • PNF and Movement
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    • v.7 no.2
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    • pp.1-10
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    • 2009
  • This research measures the conditions of spinal scoliosis of college students and analyses the factors that affect spinal scoliosis. From September 15, 2008 to October 30, 2008, the study was conducted with 142 C College students and measured the degrees of spinal scoliosis. The analysis was evaluated according to the Pneumex Analysis program. The collected data was compiled into statistics using the SPSS PC+ 12.0 program. The results were as follows: 1. It appeared that in the cases of C curve, reverse C curve, S curve, and the normal, there was a statistical significance(p=.010) between the conditions of spinal scoliosis of the two genders. 2. It appeared that the comparison among the three groups according to the characteristics of the subjects showed a statistical significance in spinal length(p=.000) in the C curve group, age(p=.019) and spinal length(p=.004) in the reverse C curve group, and spinal length (p=.035), difference in apparent leg length(p=.019), and difference in true leg length(p=.012) in the S curve group. 3. It appeared that in the normal group without spinal scoliosis, the results of comparing the differences in apparent true leg length and spinal length according to the characteristics of the subjects showed a statistical significance in spinal length and gender(p=.000), age (p=.008), height(p=.000), and whether or not there was a regular exercise over once per week(p=.001). 4. On the correlations between C curve, reverse C curve, and S curve and differences in apparent true leg length and spinal length, it appeared that: (a) As the difference in apparent leg length gets bigger the difference in true leg length gets big in C curve(r=.551, p=.000). (b) As the difference in apparent leg length gets bigger the difference in true leg length gets big in reverse C curve(r=.511, p=.006). (c) There is no correlation in S curve.

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A Study on the Dynamic p-y Curves in Soft Clay by 1 g Shaking Table Tests (1g 진동대 실험을 이용한 연약 점성토 지반에서의 동적 p-y 곡선 연구)

  • Han, Jin-Tae;Yoo, Min-Taek;Choi, Jung-In;Kim, Myoung-Mo
    • Journal of the Korean Geotechnical Society
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    • v.26 no.8
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    • pp.67-75
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    • 2010
  • In this study, a series of 1 g shaking table tests were carried out for a single pile in soft clay with various input acceleration amplitudes and frequencies. Based on the results, dynamic p-y curves were drawn and, in turn, the dynamic p-y backbone curve was formed by connecting the peak points, corresponding to the maximum soil resistance, of the dynamic p-y curves. In order to represent the p-y backbone curve numerically, Matlock's p-y formulations for clay was used to find the initial stiffness ($k_{ini}$) and the ultimate capacity ($p_u$) of the clay, both of which are required to formulate the p-y backbone curve as a hyperbolic function. The suggested p-y backbone curve was verified through comparisons with currently available p-y curves as well as other researchers' centrifuge test results and numerical analysis results.

Proposed dynamic p-y curves on a single pile considering shear wave velocity of soil

  • Song, Sumin;Lim, Hyunsung;Park, Seongyong;Jeong, Sangseom
    • Earthquakes and Structures
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    • v.23 no.4
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    • pp.353-361
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    • 2022
  • The dynamic behavior of a single pile was investigated by using analytical and numerical studies. The focus of this study was to develop the dynamic p-y curve of a pile for pseudo-static analysis considering the shear wave velocity of the soil by using three-dimensional numerical analyses. Numerical analyses were conducted for a single pile in dry sand under changing conditions such as the shear wave velocity of the soil and the acceleration amplitudes. The proposed dynamic p-y curve is a shape of hyperbolic function that was developed to take into account the influence of the shear wave velocity of soil. The applicability of pseudo-static analysis using the proposed dynamic p-y curve shows good agreement with the general trends observed by dynamic analysis. Therefore, the proposed dynamic p-y curve represents practical improvements for the seismic design of piles.

INFERENCE FOR ABSOLUTE LORENZ CURVE AND ABSOLUTE LORENZ ORDERING

  • Arora Sangeeta;Jain Kanchan;Pundir Sudesh
    • Journal of the Korean Statistical Society
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    • v.35 no.3
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    • pp.305-316
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    • 2006
  • Absolute Lorenz curve plays an important role for measuring absolute income inequality. Properties of absolute Lorenz curve are listed. Asymptotically distribution free and consistent tests have been proposed for comparing two absolute Lorenz curves in the whole interval [P1, P2] where 0 < P1 < P2 < 1. Absolute Lorenz ordering has been discussed for some distributions.

Comparison of Lateral Pile Behavior under Static and Dynamic Loading by Centrifuge Tests (원심모형 실험을 이용한 지반-말뚝 상호작용의 정적 및 동적 거동 평가)

  • Yoo, Min-Taek;Kwon, Sun-Yong
    • Journal of the Korean Geotechnical Society
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    • v.34 no.7
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    • pp.51-58
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    • 2018
  • In this study a series of centrifuge tests were carried out in dry sand to analyze the comparison of lateral pile behavior for static loading and dynamic loading condition. In case of static loading condition, the lateral displacement was applied up to 50% of pile diameter by deflection control method. And the input sine wave of 0.1 g~0.4 g amplitude and 1 Hz frequency was applied at the base of the soil box using shaking table for dynamic loading condition. From comparison of experimental static p-y curve obtained from static loading tests with API p-y curves, API p-y curves can predict well within 20% error the ultimate subgrade reaction force of static loading condition. The ultimate subgrade reaction force of experimental dynamic p-y curve is 5 times larger than that of API p-y curves and experimental static p-y curves. Therefore, pseudo-static analysis applied to existing p-y curve for seismic design could greatly underestimate the soil resistance at non-linear domain and cause overly conservative design.

타원곡선위에서의 연산

  • 최영주;황효선
    • Review of KIISC
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    • v.3 no.1
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    • pp.86-90
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    • 1993
  • Finite field GF$(2^n)5에서 정의된 elliptic curve가 있을때 그 curve위의 어떤 point p를 k배하는 연산은 암호론에서 매우 자주 쓰여진다. 이때 optimal normal bases를 이용하여 GF$(2^n)의 element를 표현하고, 또 elliptic curve를 선택할 때 animalous curve가 되도록 한다면, 기존이 방법 보다 매우 빠르게 k P를 구할 수 있다.

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Development of Dynamic p-y Curve for Jacked Pile by Centrifuge Test (원심모형 실험을 이용한 압입말뚝에 대한 동적 p-y 곡선 산정)

  • Yoo, Min-Taek;Kwon, Sun-Yong;Lee, Il-Hwa
    • Journal of the Korean Geotechnical Society
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    • v.32 no.3
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    • pp.39-47
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    • 2016
  • In this study, dynamic centrifuge tests in dry sand were conducted in order to evaluate the effect of pile installation on the dynamic p-y curve. According to the result of the pile installation effect on the dynamic p-y backbone curves, the subgrade resistance of a jacked pile in 40 g was found to be greater than that of a jacked pile in 1 g and a preinstalled pile in 1 g. It was also found that differences of the subgrade resistance decrease with the depth of the pile. Applicability of dynamic p-y backbone curve for the bored pile proposed by preceded researcher was evaluated by comparing with the result of centrifuge tests. In addition, dynamic p-y backbone curve for jacking/driven pile was developed by modifying that for the bored pile.

AVERAGE VALUES ON THE JACOBIAN VARIETY OF A HYPERELLIPTIC CURVE

  • Chung, Jiman;Im, Bo-Hae
    • Bulletin of the Korean Mathematical Society
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    • v.56 no.2
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    • pp.333-349
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    • 2019
  • We give explicitly an average value formula under the multiplication-by-2 map for the x-coordinates of the 2-division points D on the Jacobian variety J(C) of a hyperelliptic curve C with genus g if $2D{\equiv}2P-2{\infty}$ (mod Pic(C)) for $P=(x_P,y_P){\in}C$ with $y_P{\neq}0$. Moreover, if g = 2, we give a more explicit formula for D such that $2D{\equiv}P-{\infty}$ (mod Pic(C)).

Evaluation of Pressure-Temperature Limit Curve for the Safe Operation of an RFV based on 3-D Finite Element Analyses (유한요소해석을 이용한 원자로용기 압력-온도 한계곡선의 평가)

  • Lee, Taek-Jin;Park, Yun-Won;Lee, Jin-Ho;Choe, Jae-Bung;Kim, Yeong-Jin
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.25 no.10
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    • pp.1567-1574
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    • 2001
  • In order to operate an RPV safely it is necessary to keep the pressure-temperature (P-T) limit during the heatup and cooldown process. While the ASME Code provides the P-T limit curve for safe operation, this limit curve has been prepared under conservative assumptions In this paper the effects of conservative assumptions involved in the P-T limit curve specified in the ASME Code Sec. XI were investigated. Three different parameters the crack depth the cladding thickness and the cooling rate, were reviewed based on 3-D finite element analyses. Also the constraint effect on P-T limit curve generation was investigated based on J- T approach. It was shown that the crack depth and the constraint effect change the safe region in P-T limit curve significantly Therefore it is recommended to prepare a more precise P-T limit curve based on finite element analysis to obtain P-T limit for safe operation of an RPV.

Numerical response of pile foundations in granular soils subjected to lateral load

  • Adeel, Muhammad B.;Aaqib, Muhammad;Pervaiz, Usman;Rehman, Jawad Ur;Park, Duhee
    • Geomechanics and Engineering
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    • v.28 no.1
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    • pp.11-23
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    • 2022
  • The response of pile foundations under lateral loads are usually analyzed using beam-on-nonlinear-Winkler-foundation (BNWF) model framework employing various forms of empirically derived p-y curves and p-multipliers. In practice, the p-y curve presented by the American Petroleum Institute (API) is most often utilized for piles in granular soils, although its shortcomings are recognized. The objective of this study is to evaluate the performance of the BNWF model and to quantify the error in the estimated pile response compared to a rigorous numerical model. BNWF analyses are performed using three sets of p-y curves to evaluate reliability of the procedure. The BNWF model outputs are compared with results of 3D nonlinear finite element (FE) analysis, which are validated via field load test measurements. The BNWF model using API p-y curve produces higher load-displacement curve and peak bending moment compared with the results of the FE model, because empirical p-y curve overestimates the stiffness and underestimates ultimate resistance up to a depth equivalent to four times the pile diameter. The BNWF model overestimates the peak bending moment by approximately 20-30% using both the API and Reese curves. The p-multipliers are revealed to be sensitive on the p-y curve used as input. These results highlight a need to develop updated p-y curves and p-multipliers for improved prediction of the pile response under lateral loading.