• Structural Engineering and Mechanics
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• 제54권2호
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• pp.291-304
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• 2015

Compared with the identification of linear structures, it is more challenging to conduct identification of nonlinear structure systems, especially when the locations of structural nonlinearities are not clear in structural systems. Moreover, it is highly desirable to develop methods of parametric identification using partial measurements of structural responses for practical application. To cope with these issues, an identification method is proposed in this paper for the detection and parametric identification of structural nonlinear restoring forces using only partial measurements of structural responses. First, an equivalent linear structural system is proposed for a nonlinear structure and the locations of structural nonlinearities are detected. Then, the parameters of structural nonlinear restoring forces at the locations of identified structural nonlinearities together with the linear part structural parameters are identified by the extended Kalman filter. The proposed method simplifies the identification of nonlinear structures. Numerical examples of the identification of two nonlinear multi-story shear frames and a planar nonlinear truss with different nonlinear models and locations are used to validate the proposed method.

• Journal of Mechanical Science and Technology
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• 제18권11호
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• pp.1969-1977
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• 2004

To model and understand the physics of partial rub, a nonlinear rotor model is sought by applying a nonlinear parameter identification technique to the experimental data. The results show that the nonlinear terms of damping and stiffness should be included to model partial rotor rub. Especially, the impact and friction during the contact between rotor and stator are tried to explain with a nonlinear model on the basis of experimental data. The estimated nonlinear model shows good agreements between the numerical and the experimental results in its orbit. Also, the estimated nonlinear model could explain the backward whirling orbit and jump phenomenon, which are the typical phenomena of partial rub.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.663-668
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• 2004

To model and understand the physics of partial rub, a nonlinear rotor model is investigated by applying nonlinear parameter identification technique to the experimental data. The results show that the nonlinear terms of damping and stiffness should be included to model partial rotor rub. Especially, the impact and friction during the contact between rotor and stator are tried to explain with the nonlinear model on the basis of experimental data. The estimated nonlinear model shows good agreements between numerical and experimental results in its orbit.

• Journal of Electrical Engineering and Technology
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• 제9권1호
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• pp.259-267
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• 2014

This paper presents a simple, consistent and reliable technique to identify detected partial discharges (PD) using an acoustic ultrasonic method. A new reliable algorithm named 'Simple Partial Discharge Identifier' (SPDI) is proposed to perform identification process of the detected ultrasonic signals of PD. Experimental works based on recommended practices were setup and the ultrasonic signals of the PD were recorded. The PD data is then employed as the reference data. The SPDI developed has been tested against commonly used models in Neural Network (NN). Results from the SPDI algorithm shows more reliable results compared to NN models results. Comparison made on the mean square error (MSE) results shows SPDI produces the desired outcome with lower MSE in 97.17% of trials. Low error of SPDI indicates a high reliability to be applied in the identification of PD.

• Journal of information and communication convergence engineering
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• 제21권3호
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• pp.233-238
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• 2023

This study presents a method for identifying partial discharge defects in an eco-friendly gas insulated system using a backpropagation algorithm. Four partial discharge (PD) electrode systems, namely, a free-moving particle, protrusion on the conductor, protrusion on the enclosure, and voids, were designed to simulate PD defects that can occur during the operation of eco-friendly gas-insulated switchgear. The PD signals were measured using an ultrahigh-frequency sensor as a nonconventional method based on IEC 62478. To identify the types of PD defects, the PD parameters of single PD pulses in the time and frequency domains and the phase-resolved partial discharge patterns were extracted, and a back-propagation algorithm in the artificial neural network was designed using a virtual instrument based on LabVIEW. The backpropagation algorithm proposed in this paper has an accuracy rate of over 90% for identifying the types of PD defects, and the result is expected to be used as a reference database for asset management and maintenance work for eco-friendly gas-insulated power equipment.

• 대한기계학회논문집
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• 제15권6호
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• pp.1819-1830
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• 1991

본 연구에서는 구조물이 순수한 선형계인 경우에 국한하여 선형 구조물의 여 러지점에서 측정한 신호들을 기존의 방법과 같이 다중입력으로 간주하고 선형 구조물 로부터 방사된 소음, 즉 관측자의 위치에서 측정한 신호를 출력으로 가정한 두 부분 기여도 함수를 적용하여 소음/진동원을 규명하였을 때 발생하는 결과를 이론적으로 해 석하여 보았다.

• 대한기계학회논문집A
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• 제21권7호
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• pp.1127-1140
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• 1997

With the study for identifying the transmission characteristics of vibration and noise generated by operating engine system of a vehicle, recently many engineers have studied actively the reduction of vibration and noise inducing uncomfortableness to the passenger. In this study, output noise was analyzed by multi-dimensional spectral analysis and vector synthesis method. The multi-dimensional analysis method is very effective in case of identification of primary source, but this method has little effect on suggestion for interior noised reduction. For compensation of this, vector synthesis method was used to obtain effective method for interior noise reduction, after identifying primary source for output noise. In this paper, partial coherence function of each input was calculated to know which input was most coherent to output noise, then with simulation of changes for input magnitude and phase by vector synthesis diagram, the trends of synthesized output vector was obtained. As a result, the change of synthesized output vector could be estimated.

• 한국식품과학회지
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• 제30권3호
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• pp.655-659
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• 1998

우리나라 각지에서 젓갈류를 수집하여 혈전용해능을 나타내는 균주들을 분리하였다. 분리된 균주들의 활성을 측정한 결과 2.04 plasmin unit의 가장 우수한 혈전용해활성을 나타내는 균주를 선별하여 동정하였다. 균주의 형태학적, 배양학적 및 생화학적 성질을 조사한 결과 Bacillus pumilus로 나타났으나, 균체의 지방산조성을 분석하여 동정한 결과 Bacillus atropheus로 나타났다. 최종적 결론을 얻기 위해, 16S rRNA partial sequence(V3 region)를 결정하여 분석한 결과 Bacillus subtilis의 16S rRNA partial sequence와 동일한 것으로 나타나, Bacillus subtilis KJ-48로 명명하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.825-830
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• 2004

Kinematic calibration of Gough-Stewart platform using a new measurement device is presented in this paper. The device simultaneously measures components of position and orientation using commercially available gadgets. Additional kinematic parameters are defined to model the sources of inaccuracies for the proposed measurement device. Computer simulations reveal that all kinematic parameters of the Gough-Stewart platform and the additional kinematic parameters of the measurement device can be identified with the partial pose measurements of the device. Results also show that identification is robust for the initial errors and the noise in measurements. The device also facilitates the automation of easurement procedure.

• Asia pacific journal of information systems
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• 제15권4호
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• pp.1-26
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• 2005

This study was to identify the concepts and dimensions of interactivity and to examine the effect of interactivity on identification, relationship quality, and loyalty of e-brand in Internet sites using structural equation model(SEM). For these purposes, the authors developed several hypotheses. The results are as follows. First, control is not associated with identification, but is positively associated with relationship quality. Second, two-way communication is not associated with identification and relationship quality. Third, responsiveness is associated with identification and relationship quality. Fourth, identification is associated with relationship quality. Fifth, identification is not associated with loyalty, while relationship quality is associated loyalty. This means that identification and relationship quality play the partial mediating roles in the relationship between interactivity and loyalty. At the end of this paper, managerial implications, limitations, and future research directions were suggested.