• 한방재활의학과학회지
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• 제23권4호
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• pp.143-158
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• 2013

Objectives The aim of this study is to contribute to developing questionnaire for pattern identification of chronic low back pain using delphi method. Methods The questionnaire which includes symptoms and signs of chronic low back pain is studied by delphi method. Seven experts of Korean medicine, especially of rehabilitation medicine participated in delphi examination. Delphi examination was carried out through evaluating and correcting the questionnaire by e-mail. Results By the Delphi method and score evaluation, 20 items of the initial copy of questionnaire are chosen for pattern identification of chronic low back pain. Conclusions By the delphic method among experts, a reference questionnaire for pattern identification of chronic low back pain was suggested. Further research is necessary for modification of questionnaire by statistics and certification by clinical trial research.

• Structural Engineering and Mechanics
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• 제27권4호
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• pp.409-424
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• 2007

In this paper, an identification method of impact force is proposed for composite structures. In this method, the relation between force histories and strain responses is first formulated. The transfer matrix, which relates the strain responses of sensors and impact force information, is constructed from the finite element method (FEM). Based on this relation, an optimization model to minimize the difference between the measured strain responses and numerically evaluated strain responses is built up to obtain the impact force history. The identification of force history is performed by a modified least-squares method that imposes the penalty on the first-order derivative of the force history. Moreover, from the relation of strain responses and force history, an error vector indicating the force location is defined and used for the force location identification. The above theory has also been extended into the cases when using acceleration information instead of strain information. The validity of the present method has been verified through two experimental examples. The obtained results demonstrate that the present approach works very well, even when the internal damages in composites happen due to impact events. Moreover, this method can be used for the real-time health monitoring of composite structures.

• Structural Monitoring and Maintenance
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• 제11권3호
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• pp.203-217
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• 2024

Electro-mechanical impedance (EMI) technique is a low-cost structural damage detection method. It reflects structural damage through the change in admittance signal which contains the structural mechanical impedance information. The ambient temperature greatly affects the admittance signal, which hides the changes caused by structural damage and reduces the accuracy of damage identification. This study introduces a convolutional neural network to compensate for the temperature effect. The proposed method uses a framework that consists of a feature extraction network and a decoding network, and the original admittance signal with temperature information is used as the input. The output admittance signal is eliminated from the temperature effect, improving damage identification robustness. The admittance data simulated by the finite element model of the spatial grid structure is used to verify the effectiveness of the proposed method. The results show that the proposed method has advantages in identification accuracy compared with the damage index minimization method and the principal component analysis method.

• 대한수학회지
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• 제41권3호
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• pp.435-459
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• 2004

Identification problems for the system governed by abstract nonlinear damped second order evolution equations are studied. Since unknown parameters are included in the diffusion operator, we can not simply identify them by using the usual optimal control theories. In this paper we present how to solve our identification problems via the method of transposition.

• Journal of Advanced Marine Engineering and Technology
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• 제18권3호
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• pp.34-42
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• 1994

The present study is aimed to improve the PIV performance by suggesting a two-frame particle identification technique and by introducing estimation method of wall pressure distribution from the velocity data. Adopted image processing system consists of one commercial image board slit into a personal computer, 2-D sheet light generator, flow picture recording apparatus and related particle identification software. A revised particle tracking method essential to PIV performance is obtained by particle centroid correlation pairing (CCP) and its effectiveness is ascertained by comparison with multi-frame identification.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.837-840
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• 1997

This paper provides an experimental verification of an FRF-based structural damage identification method (SDIM) developed by the authors for beam structures. The FRF-based SDIM requires the following data : (1) natural frequencies and mode shapes measured at the intact state and (2) the FRF-data measured at the damaged state. Experiments are conducted for the cantilevered beam with one slot and three slots. It is shown that the FRF-based SDIM developed by the authors provide very successful damage identification results which agree well with true damage state.

• The Korean Journal of Legal Medicine
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• 제42권4호
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• pp.141-145
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• 2018

There have been many radiographic studies on age estimation that evaluate reduction in size of dental pulp cavity with secondary dentin formation. The Paewinsky method reported high accuracy in estimating ages by measuring the width of the pulp cavity in panoramic radiographs. The aim of this study was to evaluate the application of the Paewinsky method to digital periapical radiographs. This study was conducted on 103 cases that reported to the Section of Human Identification of the National Forensic Service. The age was calculated by applying the Paewinsky method that measures the root and pulp canal width at three points in a tooth. The estimation results were compared with those calculated by the Johanson method. When the Paewinsky models were applied to digital periapical radiographs, the errors were significantly greater as compared to the original study. The errors of the maxillary second premolar and mandibular lateral incisor were greater than those of the maxillary central incisor, lateral incisor, mandibular canine, and first premolar. Furthermore, errors of the age estimation models in level C were greater than those in levels A and B. This study could be a reference for the application of the Paewinsky method to digital periapical radiographs.

• International Journal of Internet, Broadcasting and Communication
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• 제7권2호
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• pp.149-154
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• 2015

Biometric techniques for authentication using body parts such as a fingerprint, face, iris, voice, finger-vein and also photoplethysmography have become increasingly important in the personal security field, including door access control, finance security, electronic passport, and mobile device. Finger-vein images are now used to human identification, however, difficulties in recognizing finger-vein images are caused by capturing under various conditions, such as different temperatures and illumination, and noise in the acquisition camera. The human photoplethysmography is also important signal for human identification. In this paper To increase the recognition rate, we develop camera based identification method by combining finger vein image and photoplethysmography signal. We use a compact CMOS camera with a penetrating infrared LED light source to acquire images of finger vein and photoplethysmography signal. In addition, we suggest a simple pattern matching method to reduce the calculation time for embedded environments. The experimental results show that our simple system has good results in terms of speed and accuracy for personal identification compared to the result of only finger vein images.

• 전자공학회논문지B
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• 제33B권11호
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• pp.127-139
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• 1996

In this paper we propose a new controller design method using hybrid fuzzy-neural netowrk and neural network identification in order ot control systems which are more and more getting nonlinearity. Proposed method performs, for a nonlinear plant with unknown functions, hybird identification using a fuzzy-neural network and a neural network, and then a stable nonlinear controller is designed with those identified informations. To identify a nonlinear function, which is directly related to input signals, we can use a neural network which is satisfied with the proposed stable condition. To identify a nonlinear function, which is not directly related to input signals, we can use a fuzzy-neural network which has excellent identification characteristics. In order to verify excellent control performances of the proposed method, we compare the porposed control method with a conventional neural network control method through simulations and experiments with one link manipulator.

• Structural Monitoring and Maintenance
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• 제3권4호
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• pp.395-406
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• 2016

Modal parameter identification has received much attention recently for their usefulness in earthquake engineering, damage detection and structural health monitoring. The identification method based on Matrix Pencil technique is adopted in this paper to identify structural modal parameters, such as natural frequencies, damping ratios and modal shapes using impulse vibration responses. This method can also be applied to dynamic responses induced by stationary and white-noise inputs since the auto- and cross-correlation function of the two outputs has the same form as the impulse response dynamic functions. Matrix Pencil method is very robust to noise contained in the measurement data. It has a lower variance of estimates of the parameters of interest than the Polynomial Method, and is also computationally more efficient. The numerical simulation results show that this technique can identify modal parameters accurately even if the noise level is high.