• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.10
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• pp.522-527
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• 2003

This paper proposes a new speed and flux estimation method which has the robustness against the variation of the electrical parameters of the motor and the superiority in the dynamic characteristics. In the proposed method, the stator currents and the rotor fluxes are observed on the stationary reference frame using the sliding mode concept. And the rotor speed is estimated using the current estimation errors and the observed rotor fluxes based on the Lyapunov stability theory. Also a design method of the observer gain is proposed to minimize the effect of the speed estimation error on the rotor flux observation. The experimental results are shown to verify that the proposed method shows the excellent performances under the variations of motor resistance and inductance.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1995.10a
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• pp.95-102
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• 1995

Procedures for estimation of axial or flexural rigidities of bridge members by neural networks are shown. To treat large scale structures containing many unkwon parameters, substructuring concept is introduced. The measurement points are selected considering the sensitivity of the element stiffnesses of interest. Utilization of relative mode vectors is found to be very effective for the local parameter estimation. Then, the study focuses on the method to obtain the training set enough to represent structures. It is shown that noise injection is effective to reduce the estimation errors caused by measurement noise. Verification of the present method is carried out using a cable-stayed bridge model.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.5
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• pp.751-757
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• 2011

The monitoring technique based on electrical conductivity (EC) can provide researchers with some advantages in maintenance management and is cost-effective as compared with existing CSOs monitoring. In this study, the flow rate estimation using EC data was executed in two sites where storm overflow chamber had installed. In the result of A-site, R2 of second order multinomial between dilution ratio of EC and observed flow rate was showed the range of 0.68 ~ 0.77. And $R^{2}$ of B-site was 0.62 ~ 0.81. On the other hand, cumulative frequency of A-site was 43.4 ~ 52.2% in the relative error level of under 20%. And B-site was 10.1 ~ 46.5%. The flow rate estimation formula was improved through consideration of some parameters including antecedent dry days and rainfall duration. And difference between estimated flow rate and observed flow rate in total rainfall event was very small.

• Journal of Power Electronics
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• v.16 no.6
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• pp.2150-2161
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• 2016

Mechanical and electrical parameter uncertainties cause dynamic and static estimation errors of the rotor speed and position, resulting in performance deterioration of sensorless control systems. This paper applies an extended nonlinear observer to interior permanent magnet synchronous motors (IPMSM) for the simultaneous estimation of the rotor speed and position. Two compensation methods are proposed to improve the observer performance against parameter uncertainties: an on-line rotational inertia adjustment approach that employs the gradient descent algorithm to suppress dynamic estimation errors, and an equivalent flux error compensation approach to eliminate static estimation errors caused by inaccurate electrical parameters. The effectiveness of the proposed control strategy is demonstrated by experimental tests.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.3
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• pp.163-175
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• 1996

This paper invetigates estimation methods of mapping parameters in object-oriented coding. In this paper, we propose a fast parameter estimation method with its performance similar to that of the conventional methods. We employ hierarchical structure in difference images to redcue the computational complexity and also combine conventional six- and eight-mapping parameter estimation methods to compensate for the performance degradation caused by employment of hierarchical structure. Computer simulation shows that the proposed mehtod gives results similar to conventional methods with greatly reduced computational complexity.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.435-436
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• 2006

When working with multi-view images, imbalances between multi-view images occur a serious problem in multi-view video coding because they decrease the performance of disparity estimation. To overcome this problem, we propose inter-view balanced disparity estimation for multi-view video coding. In general, the imbalance problem can be solved by a preprocessing step that transforms reference images linearly. However, there are some problems in pre-processing such as the transformation of the original images. In order to obtain a balancing effect among the views, we perform block-based disparity estimation, which includes several balancing parameters.

• Journal of Power Electronics
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• v.11 no.6
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• pp.864-869
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• 2011

This paper presents a sensorless control and parameter estimation strategies for a Transverse Flux Rotating Motor (TFRM). The proposed sensorless control method is based on a Model Reference Adaptive System (MRAS) to estimate the stator flux. Parameter estimation theory is also applied into the sensorless control method to estimate motor parameters, such as inductances. The effectiveness of the proposed methods is verified by some simulations and experiments.

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.447-448
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• 2013

This paper investigates a new approach based on the fuzzy-logic controlled methodology that is suitable for analyzing and evaluating large format $LiMn_2O_4$ cell performance via online state-of-health (SOH) estimation for energy storage system (ESS) applications. First of all, the values of the cell resistance R and maximum cell capacity $Q_{max}$ are calculated from three factors such as voltage, current, and time that were measured by discharging/charging sequence. Then, using two values R and $Q_{max}$ previously calculated, present SOH of an arbitrary $LiMn_2O_4$ cell can be estimated using the defined fuzzy-logic inference system. The main advantage of this approach is wide parameters tuning possibility for good correspondence of SOH decay with other accurate estimation method and the possibility to perform suitable online SOH estimation.

• Korean Journal of Computational Design and Engineering
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• v.22 no.2
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• pp.215-221
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• 2017

This paper describes a method of precise estimation for printing time and material consumption which are directly related to the 3D printing cost. Printing process and head motion of 3D printers using digital printing head, which is analyzed by its digitized steps, is rapidly simulated without slicing to calculate estimated printing results. Using this method, printing time and material usage of 3D printer were estimated quickly and precisely and compared to the real printing result. Applying compensation using the printing parameters, transferred from the 3D printer to the printing estimation system, even more accurate estimation is achieved. This method is used in the 3D Sprint software.

• Structural Engineering and Mechanics
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• v.56 no.3
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• pp.423-442
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• 2015

This study examines the wavelet transform for output-only system identification of ambient excited engineering structures with emphasis on its utilization for modal parameter estimation of high-order and closely-spaced modes. Sophisticated time-frequency resolution analysis has been carried out by employing the modified complex Morlet wavelet function for better adaption and flexibility of the time-frequency resolution to extract two closely-spaced frequencies. Furthermore, bandwidth refinement techniques such as a bandwidth resolution adaptation, a broadband filtering technique and a narrowband filtering one have been proposed in the study for the special treatments of high-order and closely-spaced modal parameter estimation. Ambient responses of a 5-story steel frame building have been used in the numerical example, using the proposed bandwidth refinement techniques, for estimating the modal parameters of the high-order and closely-spaced modes. The first five natural frequencies and damping ratios of the structure have been estimated; furthermore, the comparison among the various proposed bandwidth refinement techniques has also been examined.