• Structural Engineering and Mechanics
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• 제45권2호
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• pp.159-168
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• 2013

The effect of structural uncertainties or measurement errors on damage detection results makes the robustness become one of the most important features during identification. Due to the wide use of vibration signatures on damage detection, the development of vibration-based techniques has attracted a great interest. In this work, a review on vibration-based robust detection techniques is presented, in which the robustness is considerably improved through modeling error compensation, environmental variation reduction, denoising, or proper sensing system design. It is hoped that this study can give help on structural health monitoring or damage mitigation control.

• 한국구조물진단유지관리공학회 논문집
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• 제13권2호통권54호
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• pp.181-188
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• 2009

교량 지지용으로 사용되는 강재 케이블에 대한 장력측정은 교량 안전관리의 중요한 측정항목이다. 현재 케이블에 걸린 장력을 진동법과 로드셀로 측정하고 있으며, 최근에는 선진국에서 자기적 방식에 의한 장력측정 방법을 연구하여 이에 대해 여러 가지 결과물을 제공하고 있다. 그러나 아직 우리나라에서는 이에 대한 체계적인 연구가 수행되지 않고 있어 자기적 방식에 의한 장력측정 연구를 시작하였으며 장력측정 정밀도 향상을 위해 연구하고 있다. 자기적 방식의 장력측정에서 강재 케이블 내의 온도와 자기장에 대한 영향을 검토해야 한다. 금번 논문에서는 온도에 따라 장력센서의 출력특성을 시험하였고 주어진 자기장에서 온도보정계수를 도출하였으며 시험실 내의 장력측정 시스템에 보정계수를 적용하여 케이블 장력에 따른 장력센서의 출력특성에 대한 시험 결과를 분석하고 평가하였다.

• 마케팅과학연구
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• 제19권4호
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• pp.57-63
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• 2009

随着电子商务指数式增长(电子商务), 营销人员正试图获得通过强调服务质量和服务方面的相互作用而导致客户满意度或行为后果的竞争优势. 特别是对于服装, 服务质量是鼓励客户电子忠诚的关键因素之一, 并增加电子商务中服装零售的成功. 因此, 本研究探讨电子服务质量(电子SERVQUAL)的因素和根据Parasuraman等人(2005)的研究框架对网上服装购物的电子忠诚度的独特影响. 这项研究的具体目标是确定的基本层面的E - SERVQUAL, 分析有关在网上服装购物中电子SERVQUAL对点在忠诚度的影响的结构模型. 对于服务质量, 在网上购物方面的理论框架, 我们比较分析了有关传统和电子服务质量的因素的文献并确定了核心的两个方面和恢复服务. 这项研究的假设是电子SERVQUAL对电子忠诚度的影响. 客户满意度对电子服装网上购物服务的忠诚度有积极影响和客户满意度在电子SERVQUAL对服装网上购物电子忠诚度影响中的中介作用. 根据文献我们制成了一份自填式的问卷. 我们在美国从居住在大城市的有在网上购买服装产品的在线消费者中获得了252份有用的问卷. 通过因子分析(例如, 探索, 验证)评估了有效性和可靠性, 结构方程模型, 包括测量和结构模型, 通过线性结构8.8程序评估了包括测量和结构模型的结构方程模型. 结果显示, 网上购物网站的电子SERVQUAL的五个因素: 赔偿, 执行, 效率, 系统可用性和反应能力. 这支持在网上服装购物方面Parasuraman(2005)的E-S-QUAL包括两个方面的核心服务(如满足, 效率, 系统可用性)和恢复相关的服务(例如, 补偿, 回应). 在结构方程模型中, 有5个电子SERVQUAL因素的外生潜变量, 两个内生潜变量(例如客户满意度, 电子忠诚度). 对于测量模型, 各代表概念的因子载荷有显著的统计学意义, 比 0.60大, 内部一致性信从 0.85 至 0.8 8 不等. 在估计电子SERVEQUAL因素的结构模型, 系统的可用性对电子忠诚的直接和积极的作用, 而效率对网上服装购物的电子忠诚度有负面影响. 然而, 满足不是解释网上服装购物的电子SERVQUAL结果的重要指标. 这一发现意味着, 可被理解为系统提供服务的质量可能会增加对服装网上购物的客户满意度. 然而, 电子忠诚取决于服务质量没有被支持, 因为在网上服装购买中, 通过价值或满意度的中介作用, 服务质量对电子忠诚度(例如再购买意图)有间接影响. 此外, 获得赔偿和回应被发现对客户满意度有显著影响, 会影响网上服装购买的电子忠诚度. 因此, 获得赔偿和回应对电子忠诚度有显著的间接影响. 这表明, 恢复特定的服务因素在客户满意度最大化方面的重要作用, 以及维护客户对网上服装购物网站的忠诚度方面的重要作用. 研究结果在管理和研究方面都有启示. 时装营销者可以在建立与客户的长期关系的基础上, 不断测量顾客感知与恢复服务有关的服务质量等问题, 例如对问题和返回的迅速反应, 客户购买之后的问题赔偿. 为了保持电子忠诚, 在消费者购买服装中恢复服务对消费者第一次选择网站起到重要作用. 由于网上购物的消费者可以在任何地方购物, 提高竞争优势的营销策略是为消费者提供更好的服务质量, 最大限度地满意, 并把创造客户网上服装购买的电子忠诚度. 从研究的角度来看, 解释这些结果时, 本研究的一些局限需要被考虑. 对于未来的研究, 调查结果为这一重要主题理论和实证方面的进一步的研究提供了依据. 根据研究结果, 更全面的模型预测电子SERVQUAL的结果可以被开发和测试. 对全球时装市场, 这项研究可以扩展使用多国样本的跨文化的方法来研究服装的电子服务质量.

• Structural Engineering and Mechanics
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• 제58권6호
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• pp.1127-1143
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• 2016

The pounding phenomenon in adjacent structures happens in severing earthquakes that can cause great damages. Connecting neighboring structures with active and semi-active control devices is an effective method to avoid mutual colliding between neighboring buildings. One of the most important issues in control systems is applying online control force. There will be a time delay if the prose of producing control force does not perform on time. This paper proposed a time-delay compensation method in coupled structures control, with semi-active Magnetorheological (MR) damper. This method based on Newmark's integration is adopted to mitigate the time-delay effect. In this study, Lyapunov's direct approach is employed to compute demanded voltage for MR dampers. Using Lyapunov's direct algorithm guarantees the system stability to design a controller based on feedback. Because of the strong nonlinearity of MR dampers, the equation of motion of coupled structures becomes an involved equation, and it is impossible to solve it with the common time step methods. In present paper modified Newmark-Beta integration based on the instantaneous optimal control algorithm, used to solve the involved equation. In this method, the response of a coupled system estimated base on optimal control force. Two MDOF structures with different degrees of freedom are finally considered as a numeric example. The numerical results show, the Newmark compensation is an efficient method to decrease the negative effect of time delay in coupled systems; furthermore, instantaneous optimal control algorithm can estimate the response of structures suitable.

• 전기학회논문지
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• 제59권10호
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• pp.1874-1881
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• 2010

A recursive linear stochastic error compensation algorithm is newly proposed for target localization in sensor network which provides range difference of arrival(RDOA) measurements. Target localization with RDOA is a well-known nonlinear estimation problem. Since it can not solve with a closed-form solution, the numerical methods sensitive to initial guess are often used before. As an alternative solution, a pseudo-linear estimation scheme has been used but the auto-correlation of measurement noise still causes unacceptable estimation errors under low SNR conditions. To overcome these problems, a stochastic error compensation method is applied for the target localization problem under the assumption that a priori stochastic information of RDOA measurement noise is available. Apart from the existing methods, the proposed linear target localization scheme can recursively compute the target position estimate which converges to true position in probability. In addition, it is remarked that the suggested algorithm has a structural reconciliation with the existing one such as linear correction least squares(LCLS) estimator. Through the computer simulations, it is demonstrated that the proposed method shows better performance than the LCLS method and guarantees fast and reliable convergence characteristic compared to the nonlinear method.

• E2M - 전기 전자와 첨단 소재
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• 제8권5호
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• pp.640-647
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• 1995

In this study, the BaTiO$\sub$3/ capacitor add to MnO$\sub$2/ like depressor and shifter were investigated for temperature or voltage compensation by structural and electrical analysis. The relative density of BCTM, generating poly crystall and formation of lattice defect, has a 90[%] over as the CaTiO$\sub$3/ come out to control grain size. The current density of BCTM2 increased non-ohmic in high-electric field but that BCTM3 and BCTM4 had a few changing. The BCTM3 and BCTM4 unformated grain boundary shown temperature compensation properties, so that the dielectric constant was low value. The curie point was near 140[.deg. C] in BCTM1 and BCTM4, but BCTM3 and BCTM4 not shown the curie point. It is found that the charging energy of BCTM4 was changed 6[%] according to rising temperature from room temperature to 417[K]. The formation of BaMnO$\sub$3/ was low dielectric constant to change frequency and temperature.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.488-493
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• 2005

In gun stabilization systems, the torque comes from the unbalance mass of gun and the base acceleration is an important source of disturbance which degrades stabilization performance. Fatigue of gear train is another important factor affecting structural safety problems. In this paper, a feedback control gain is designed by optimal control weighting to difference between motor and gun velocity, and a feedforward controller using FXLMS algorithm is adopted to investigate those problems. Experimental results show that the feedforward compensator based on FXLMS can reduce the disturbance effects. The directional convergence property according to initial conditions of the FXLMS is also shown through experiments.

• 대한기계학회논문집A
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• 제26권12호
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• pp.2475-2482
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• 2002

The measurement of residual stresses by the hole-drilling method has been commonly used to evaluate residual stresses in structural members. In this method, eccentricity can usually occur between the hole center and rosette gage center. In this study, the error due to the hole eccentricity is compensated using the neural network. The neural network has trained training examples of normalized eccentricity, eccentric direction and direction of maximum stress at eccentric case using backpropagation learning process. The trained neural network could compensated the error of measured residual stress in experiments with hole eccentricity. The proposed neural network is very useful for compensation of the error due to hole eccentricity in hole-drilling method.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제14권1호
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• pp.17-25
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• 2014

This paper presents the formulation of an impedance controller for regulating the contact force with the environment. To achieve an accurate force tracking control, uncertainties in both robot dynamics and the environment require to be addressed. As part of the framework of the proposed force tracking formulation, a neural network is introduced at the desired trajectory to compensate for all uncertainties in an on-line manner. Compensation at the input trajectory leads to a remarkable structural advantage in that no modifications of the internal force controllers are required. Minimizing the objective function of the training signal for a neural network satisfies the desired force tracking performance. A neural network actually compensates for uncertainties at the input trajectory level in an on-line fashion. Simulation results confirm the position and force tracking abilities of a robot manipulator.

• Journal of Power Electronics
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• 제13권3호
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• pp.458-468
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• 2013

Large capacity reactive power compensation and harmonic control in the low-voltage grid of an enterprise, are important technical means to improve power quality and reduce power loss. In this paper, the principle of an efficient power quality controller is analyzed. Then, key application technologies of the HPQC which would influence the performances of the HPQC are studied. Based on an analysis of the harmonic shunt problem, a frequency dividing control strategy of the HPQC continuous subsystem is proposed. A parameter design method of the HPQC discrete subsystem and its installation method are also proposed to ensure the system compensation effect. HPQC systems have been designed for a copper foil plant. The effectiveness of this paper has been verified by the simulation and application results.