• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2004년도 봄 학술발표논문집 Vol.31 No.1 (B)
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• pp.568-570
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• 2004

The error-backpropagation (EBP) algerithm for training multilayer perceptrons (MLPs) is known to have good features of robustness and economical efficiency. However, the algorithm has difficulty in selecting an optimal constant learning rate and thus results in non-optimal learning speed and inflexible operation for working data. This paper Introduces an elastic learning rate that guarantees convergence of learning and its local realization by online upoate of MLP parameters Into the original EBP algorithm in order to complement the non-optimality. The results of experiments on a speaker verification system with Korean speech database are presented and discussed to demonstrate the performance improvement of the proposed method in terms of learning speed and flexibility fer working data of the original EBP algorithm.

• 한국터널지하공간학회 논문집
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• 제12권4호
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• pp.295-306
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• 2010

암석과는 달리 절리암반은 변형률 의존적 변형특성(탄성계수 및 감쇠비)을 나타낸다. 탄성파를 이용한 현장실험을 통해 미소변형률 수준에서 암반의 최대탄성계수를 얻을 수 있으며 이를 내진 설계에 반영하고 있으나, 미소 변형률 이상의 중변형률($10^{-4}{\sim}0.5%$) 영역의 동적거동에 대한 실험적인 규명과 이에 대한 수치적 적용은 전무한 실정이다. 본 연구에서는 변형률 의존적 전단탄성계수 및 감쇠비의 비선형 거동 특성을 반영하여 동적해석을 수행할 수 있는 FLAC3D 해석 모듈을 개발하였다. 리커 웨이브의 파동 변화를 분석하여 개발된 모듈에 대한 검증을 수행하였다. 절리 암반의 탄성파 전파특성과 동적 거동특성을 모사할 수 있는 절리암반 공진주 시험장비를 통하여 현장에서 채취한 절리암반의 변형률 의존적 전단탄성 계수의 감쇠 특성과 감쇠비의 증폭 특성을 획득하였다. 개발된 비선형 해석 모듈에 실험으로부터 획득된 거동 특성을 반영하여 수직구와 사갱의 접속부에 대한 내진 안정성 평가를 수행하였다. 내진해석 결과, 비선형 해석이 선형 해석보다 더 큰 연직변위와 수평변위 결과를 나타냈다. 라이닝의 휨압축응력은 수직구과 사갱의 접속부에서 집중되는 것으로 나타났으며 비선형해석의 경우 라이닝에 더 큰 휨압축응력이 발생되는 것으로 나타났다. 본 연구를 통하여 변형률 의존적 절리암반의 비선형 거동특성을 보다 깊이 있게 이해하고 해석 및 설계시 고려할 수 있을 것으로 사료된다.

• 대한물리치료과학회지
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• 제8권2호
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• pp.1023-1032
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• 2001

The muscles relating to movement of painful low back was analyzed kinematically, by method of applying elastic tapes and putting non-elastic tapes on muscles involving those movements which cause pain and limitation of range of motion (ROM) in low back and trunk. Taping therapy which is effective for improvement of painful low back and which is supposed to facilitate the total and continual movement based on the postural reflexes will be presented in this paper. Fifty cases who had painful low back were investigated. Patients with painful low back were at first asked pain point and direction of painful movement, and then tested the muscles which are cause of those pain and limited motion. Before attaching tape, all subjects were divided into two groups, flexor pattern and extensor pattern, according to direction of increasing pain. Elastic tapes were applied from origin to insertion of objective muscles and non-elastic tapes were put on effective points of the muscles which were associated with respect to pain and limited ROM. As a result of this study, all subjects with low back pain significantly improved in pain and ROM at the low back. The longest treatment duration group for the low back pain cases was herniated lumbar disc(10.4 days) group. Low back pain have been treated by so many ways. muscles factor should be emphasized to be distinguish1y important to reduce low back pain. The muscles relating to make directly painful motion in low back and trunk should be confirmed by means of taping and painful motion should be analyzed by point of view of postural reflexes.

• 한국콘텐츠학회논문지
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• 제8권6호
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• pp.167-174
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• 2008

테이핑은 근골격계 질환의 치료 및 부상 방지를 위해 재활과 스포츠 영역에서 흔하게 사용되는 방법으로 그 작용 기전에 관한 설명은 신경생리학적 측면보다는 경험에 의한 주관적인 설명이 주를 이루고 있다. 이에 본 연구는 테이핑의 적용이 신경생리학적으로 ${\alpha}$-운동신경원의 흥분에 영향을 미치는지 여부를 알아 보고자 시도하였다. 본 연구는 20대 건강한 피검자를 대상으로 비복근의 주행 방향을 따라 탄력성 테이프와 비탄력성 테이프를 테이핑 적용 전, 적용 시 그리고 제거 후 M-파와 H-파의 진폭을 비교하여 테이핑이 D-운동신경원의 흥분에 변화를 일으키는지 여부를 알아보았다. 본 연구의 결과 탄력 테이프와 비탄력 테이프 모두는 ${\alpha}$-운등신경원의 흥분도에 어떠한 변화도 일으키지 않는 것으로 나타났다. 그러나 이러한 연구 결과는 선행 연구들과 상이한 결과로서 차후 보다 심도 있고 광범위한 연구가 수행되어야 할 것으로 사료된다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 춘계 학술발표회
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• pp.825-831
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• 2010

In this study is stress behavior of steel support structure is to identify basic research. Steel stress due to load step to determine the behavior of steel using strain gauge steel loading test was performed. Numerical analysis and steel loading test using strain gauge on the actual steel stress behavior was analyzed. First, when tensile loading 3.5tonf load side of the plastic behavior appeared. Elastic model, using numerical analysis and comparison of results, the actual value is saved and you can see some difference. This repeated loading tests on steel can be seen from the results of the stress behavior of the steel rather than the elastic behavior of elastic-plastic behavior is because you can see. In addition, the upper and lower steel stress in compression and tension behavior represents the behavior was similar, but different. Steel loading test results, Y-axis get a compression if X-axis is tension. The future based on this study, the stress sensitivity curve of magnetic anisotropy sensor for non-destructive stress measurement technique for the study will be performed. And the behavior of plastic zone and residual stress to determine the numerical analysis using non-elastic model is needed.

• Steel and Composite Structures
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• 제18권2호
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• pp.443-465
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• 2015

In this paper, an efficient and simple trigonometric shear deformation theory is presented for thermal buckling analysis of functionally graded plates. It is assumed that the plate is in contact with elastic foundation during deformation. The theory accounts for sinusoidal distribution of transverse shear stress, and satisfies the free transverse shear stress conditions on the top and bottom surfaces of the plate without using shear correction factor. Unlike the conventional trigonometric shear deformation theory, the proposed sinusoidal shear deformation theory contains only four unknowns. It is assumed that the mechanical and thermal non-homogeneous properties of functionally graded plate vary smoothly by distribution of power law across the plate thickness. Using the non-linear strain-displacement relations, the equilibrium and stability equations of plates made of functionally graded materials are derived. The boundary conditions for the plate are assumed to be simply supported on all edges. The elastic foundation is modelled by two-parameters Pasternak model, which is obtained by adding a shear layer to the Winkler model. The effects of thermal loading types and variations of power of functionally graded material, aspect ratio, and thickness ratio on the critical buckling temperature of functionally graded plates are investigated and discussed.

• Advances in nano research
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• 제15권4호
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• pp.339-353
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• 2023

This work aims to present a solution for the buckling behavior of perforated nano/microbeams with deformable boundary conditions using nonlocal strain gradient theory (NLSGT). For the first time, a solution that can provide buckling loads based on the non-local and strain gradient effects of perforated nanostructures on an elastic foundation, while taking into account both deformable and rigid boundary conditions. Stokes' transformation and Fourier series are used to realize this aim and determine the buckling loads under various boundary conditions. We employ the NLSGT to account for size-dependent effects and utilize the Winkler model to formulate the elastic foundation. The buckling behavior of the perforated nano/microbeams restrained with lateral springs at both ends is studied for various parameters such as the number of holes, the length and filling ratio of the perforated beam, the internal length, the nonlocal parameter and the dimensionless foundation parameter. Our results indicate that the number of holes and filling ratio significantly affect the buckling response of perforated nano/microbeams. Increasing the filling ratio increases buckling loads, while increasing the number of holes decreases buckling loads. The effects of the non-local and internal length parameters on the buckling behavior of the perforated nano/microbeams are also discussed. These material length parameters have opposite effects on the variation of buckling loads. This study presents an effective eigenvalue solution based on Stokes' transformation and Fourier series of the restrained nano/microbeams under the effects of elastic medium, perforation parameters, deformable boundaries and nonlocal strain gradient elasticity for the first time.

• Earthquakes and Structures
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• 제17권5호
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• pp.447-462
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• 2019

This present paper concerned with the analytic modelling for vibration of the functionally graded (FG) plates resting on non-variable and variable two parameter elastic foundation, based on two-dimensional elasticity using higher shear deformation theory. Our present theory has four unknown, which mean that have less than other higher order and lower theory, and we denote do not require the factor of correction like the first shear deformation theory. The indeterminate integral are introduced in the fields of displacement, it is allowed to reduce the number from five unknown to only four variables. The elastic foundations are assumed a classical model of Winkler-Pasternak with uniform distribution stiffness of the Winkler coefficient (kw), or it is with variables distribution coefficient (kw). The variable's stiffness of elastic foundation is supposed linear, parabolic and trigonometry along the length of functionally plate. The properties of the FG plates vary according to the thickness, following a simple distribution of the power law in terms of volume fractions of the constituents of the material. The equations of motions for natural frequency of the functionally graded plates resting on variables elastic foundation are derived using Hamilton principal. The government equations are resolved, with respect boundary condition for simply supported FG plate, employing Navier series solution. The extensive validation with other works found in the literature and our results are present in this work to demonstrate the efficient and accuracy of this analytic model to predict free vibration of FG plates, with and without the effect of variables elastic foundations.

• 대한토목학회논문집
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• 제28권3C호
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• pp.159-166
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• 2008

흙은 변형률에 따라 강성이 감소하는 비선형적 변형 특성을 가지지만, 매우 작은 변형률 영역($<10^{-3}%$)에서는 선형탄성적 특성을 갖는다고 알려져 있다. 본 연구에서는 응력 경로 시험 중 실시한 다축 벤더엘리먼트 시험을 통해 다양한 응력 상태에서 사질토의 이방적 전단탄성계수를 측정하고, 그 변화를 분석하고자 하였다. 응력 경로 시험에서는 내부 변형률 측정 장치 및 3 방향의 벤더 엘리먼트가 부착된 삼축 시험기를 이용하였다. 전단 중 응력비가 -0.5~1.5의 범위를 벗어나게 되면 축 방향 전단탄성계수는 응력과의 경험적 상관관계와 차이가 발생하였고, 이로부터 시료의 항복이 전단파 전달 구조를 변화시킴을 알 수 있었다. 수평방향 전단탄성계수의 변화는 전단 중 체적 상태의 변화와 밀접한 관계가 있음을 알 수 있었다.

• 대한물리의학회지
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• 제8권3호
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• pp.343-350
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• 2013

PURPOSE: The purpose of this study was to compare the effects of a combined non elastic taping and lumbar stabilizing exercise against lumbar stabilizing exercise only during the lumbar stabilizing exercise in chronic low back pain. METHOD: Thirty-one patients of low back pain were randomly allocated to 2 groups: lumbar stabilizing exercise group (n=16) and nonelastic taping group(n=15) with lumbar stabilizing exercise. Taping and stabilizing exercise were performed twice a week for 4 weeks. The patients were assessed using by visual analog scale (VAS) and Korean version of Oswestry disability index (KODI). The measurements of each patients were measured before the intervention and 2 weeks post-experiment and 4weeks after the intervention. All data were analyzed using by SPSS 12.0 software for Window, the experimental data was analyzed using by paired samples t-test and repeated ANOVA. All statistical tests in this study were conducted at the .05 level of significance. RESULTS: The results of this study are in the nonelastic taping group, significant difference were found in th VAS between pre-test and post-test (p<.05). In addition, there were significant differences in the VAS between the two groups at post-test(p<.05). And in the nonelastic taping group, significant difference were found in the KODI between pre-test and post-test (p<.05). However, there were no significant differences in the KODI between the two groups at post-test (p<.05). CONCLUSION: These findings suggest that combination of nonelastic taping and lumbar stabilizing exercise is more effective for low back pain than stabilizing exercise alone. In conclusion, this study indicates that stabilizing exercise combined with nonelastic taping would be recommended in the clinic.