• Geotechnical Engineering
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• v.13 no.1
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• pp.101-110
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• 1997

This paper presents a two dimensional p-version static infinite element for analyzing $1/r^n$ displacement decay type problems in unbounded media. The proposed element is developed by using shape functions based on approximate expressions of an analytical solution. Numerical results are presented for an opening in a homogeneous elastic infinite medium and a rigid footing rested on a homogeneous elastic half-space. The numerical results show the effectiveness of the proposed infinite element.

• Advances in aircraft and spacecraft science
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• v.5 no.1
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• pp.51-71
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• 2018

This work proposes a theoretical and numerical study on the behavior of a tapered shaft rotor made of composite materials by the classical version h and the version p of the finite element method. Hierarchical form functions are used to define the model. The purpose of this paper is to determine the expressions of the kinetic and potential energies of the tree necessary for the results of the equations of motion. A comparison between the version h and the p version of the finite element method of the functions of polynomial and trigonometric hierarchical forms with six degrees of freedom per node, of a composite tapered and cylindrical shaft which rotates at a constant speed about its axis. It is found that when the number of functions of form (the version p) is increased, the solution converges. It is also observed that the conicity of the shaft increases the rigidity with respect to a uniform shaft having the same mechanical properties. The numerical simulation allowed us to determine the natural frequencies and the critical speeds of the composite shaft systems are compared with those available in the literature and the effectiveness of the methods used are discussed.

• Journal of the Korean Society of Physical Medicine
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• v.9 no.1
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• pp.25-33
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• 2014

PURPOSE: The purpose of this was to translate Patient-Rated Tennis Elbow Evaluation(PRTEE) into Korean and identify the reliability and validity of a Korean version of PRTEE. METHODS: The subjects of this study were 32 patients diagnosed with lateral epicondylitis. The subjects were surveyed using a Korean version of PRTEE three times: at the first visit, one week after, and two weeks after. This questionnaire consisted of 15 questions including 5 questions about pain and 10 questions about functions. Intraclass correlation coefficients were used to measure reliability and Cronbach's alpha coefficients were used to assess internal consistency. In addition, the validity of the survey results was examined by correlating a visual analogue scale with the outcome of holding without pain. RESULTS: Test-retest reliability of Korea version PRTEE was good total ICC= .962 (CI=.922-,982). Cronbach's alpha value for PRTEE was found to be .955 and it was statistically significant (p<.05). The positive correlation between PRTEE and VAS was moderate to high (r=.753, P=.00) and statistically significant. There was also a low significant negative correlation between PRTEE and PFG (r=-.362, P=.042). CONCLUSION: The Korean version of PRTEE had reliability and validity. Therefore, it is a useful measure to evaluate the conditions of patients with lateral epicondylitis.

• Therapeutic Science for Rehabilitation
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• v.8 no.4
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• pp.77-92
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• 2019

Objective : This study aims to obtain the validation of Korean version of HOME FAST using the translation-back translation process and to evaluate the reliability. Methods : Total three stages were conducted which includes forward translation to Korean, test for degree of understanding of translated version, back translation to English, and then review and proof reading process. 21 occupational therapists were participated in the evaluation of understanding of Korean-translated HOME FAST, then some of expressions were modified for better understanding. Korean version was went through back-translation to English. Similarity between the original version and re-translated version were evaluated. Total 75 data from community dwelling elderly group were collected to assess internal consistency. Two occupational therapists simultaneously evaluated for the inter-rater reliability. Results : 11 items of Korean-translated scale were responded as having confused meaning by occupational therapists. There was some modification on expression. In the evaluation of similarity between original version and re-translated version, 3 items were selected as dissimilar items in terms of syntax and 6 items were selected in terms of semantic similarity. After the repetitive modification process, items were obtained conceptual equivalence between two different languages. Internal consistency was .62(KR20) (p<.01) and inter-rater reliability was .97(ICC) (p<.01). Conclusion : Korean version of HOME FAST was finalized through translation-retranslation process. The conceptual equivalence was established and Korean version showed highly reliable. In further study, The modification of items reflecting Korean house and life style should be conducted.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.9
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• pp.2008-2015
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• 2010

Ns-2 is a proven simulator which is widely utilized to evaluate the performance of wired and wireless network. Ns-2.33 version introduced the extended version including the modules which the core functions of existing 802.11 PHY and MAC layer are implemented. However, if the error rate, one of most important parameters to evaluate a performance of wireless network, is applied to the extended version, the simulation is ceased with several fatal errors. Furthermore, a packet error is detected and discarded on MAC layer in the traditional protocol architecture, but there is the problem which can't identify information about a packet with error by processing packet error on PHY layer in this version. In this paper, we modify the extended version to resolve the above mentioned problems. And also we perform ns-2 simulation using the modified version on the IEEE 802.11p based vehicular ad-hoc networks, and then analyze effects of error rate.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.1
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• pp.43-50
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• 1992

The purpose of this study is to ascertain the robustness of p-version model with hierarchic intergrals of Legendre shape functions in various applications including plane stress/strain, axisymmetric and shell problems. The most important symptoms of accuracy failure in modern finite elements are spurious mechanisms and a phenomenon known as locking which are exhibited for incompressible materials and irregular shapes which contain aspect ratios(R/t, a/b), tapered ratio(d/b), and skewness. The condition numbers and energy norms are used to estimate numerical errors, convergence characteristics and algorithmic efficiencies for verifying the aforementioned symptoms of accuracy failure. Numerical results from p-version models are compared with those from NASTRAN, SAP90, and Cheung's hybrid elements.

• Journal of The Korean Society of Agricultural Engineers
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• v.48 no.1
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• pp.61-68
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• 2006

The p-version nonlinear finite element model has been developed to analyze the nonlinear behavior of simply supported RC slabs strengthened with carbon fiber reinforced plastic sheets. The shape function is adopted with integral of Legendre polynomials. The compression model of concrete is based on the Kupfer's yield criterion, hardening rule, and crushing condition. The cracking behavior is modeled by a smeared crack model. In this study, the fixed crack approach is adopted as being geometrically fixed in direction once generated. Each steel layer has a uniaxial behavior resisting only the axial force in the bar direction. Identical behavior is assumed fur tension and compression of steel according to the elastic modulus. The carbon fiber reinforced plastic sheets are considered as reinforced layers of equivalent thickness with uniaxial strength and rigidity properties in the present model. It is shown that the proposed model is able to adequately predicte the displacement and ultimate load of nonlinear simply supported RC slabs by a patch with respect to reinforcement ratio, thickness and angles of CFRP sheets.

• Journal of the Korean Mathematical Society
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• v.41 no.2
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• pp.345-368
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• 2004

A preconditioning algorithm is developed in this paper for the iterative solution of the linear system of equations resulting from the p-version boundary element approximation of the three dimensional integral equation with hypersingular operators. The preconditioner is derived by first making the nodal and side basis functions locally orthogonal to the element internal bases, and then by decoupling the nodal and side bases from the internal bases. Its implementation consists of solving a global problem on the wire-basket and a series of local problems defined on a single element. Moreover, the condition number of the preconditioned system is shown to be of order $O((1＋ln/p)^{7})$. This technique can be applied to discretization with triangular elements and with general basis functions.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1993.10a
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• pp.16-23
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• 1993

The new p-version crack model is proposed to estimate the bending stress intensity factors of the thick cracked plate under flexure. The proposed model is based on high order theory and $C^{\circ}$-plate element including shear deformation. The displacements fields are defined by integrals of Legerdre polynomials which can be classified into three groups such as basic mode, side mode and internal mode. The computer implementation allows arbitrary variations of p-level up to a maximum value of 10. The bending stress intensity factors are computed by virtual crack extention approach. The effects of ratios of thickness to crack length(h/a), crack length to width(a/W) and boundary conditions are investigated. Very good agreement with the existing solution in the literature are shown for the uncracked plate as well as the cracked plate.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1992.10a
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• pp.39-44
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• 1992

This paper is concerned with formulations of the hierarchical $C^{o}$-plate element on the basis of Reissner-Mindlin plate theory. On reason for the development of the aforementioned element is that it is still difficult to construct elements based on h-version concepts which are accurate and stable against the shear locking effects. An adaptive mesh refinement and selective p-distribution of the polynomial degree using hp-version of the finite element method we proposed to verify the superior convergence and algorithmic efficiency with the help of the clamped L-shaped plate problems.s.