• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.4
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• pp.986-991
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• 2014

The PPG signal used in mobile-healthcare and telemedicine system is including the various motion artifact that is signal generated from patient's movements. Recently, although the various methods to remove motion artifacts have been suggested, the performances of these methods are still not satisfactory. Therefore, this s study suggested the novel method based on the Kalman filter and adaptive filter to remove motion artifacts, and we used various motion artifacts to analyze the performance of the proposed method. In the results of experiments, the signal-to-noise ratio of proposed method showed good performace that was 4.8 times of moving average filter.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.3
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• pp.1-8
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• 1996

This paper proposes a novel transversal filter and an optimal LMS algorithm, and show how these can be realized as an adaptive equalizer. The transversal filter consists of a walsh and block pulse functions. in the LMS algorithm with equalizers, the convergence factor is an improtant design parameter because it governs stability and convergence speed. The conventional adaptation techniques use a fixed time constant convergence factor by the trial and error method. In this paper, an optimal method in the choice of the convergence factor is proposed. The proposed algorithm is obtrained that is tailored for each filter tap and is updated at each iteration. The performance of the proposed algorithm is compared iwth those of the conventional TDL and DFT equalizers by computer simulations.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1204-1209
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• 2008

Design is important in the IT, digital appliance, and auto industries. Aesthetic and art images are being applied for better design satisfaction of the products. Various artistic image patterns are used to satisfy demand of design, but it takes much lead-time and effort to implement them for making dies and molds. In this paper, a hybrid reverse engineering method generating accurate 3D engraving models from 2D art images is proposed through image processing, 3D reconstruction, and NURBS interpolation methods. In order to generate the 3D model from the 2D artistic image, cloud points with z-depth are extracted according to intensity values of the image. An adaptive median filter and harmonic filter are used to obtain the intensity values accurately. NURBS surfaces are generated through the interpolation of the cloud points. Performance of the developed system is to be confirmed through the realization of Mona Lisa and Golden Gate Bridge.

• Journal of Korea Foundry Society
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• v.37 no.3
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• pp.71-77
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• 2017

Casting defects produced during the casting process seriously affect the mechanical properties of the resulting products, reduce the performance capabilities of the product, and also result in economic losses. Therefore, this paper mainly investigates the causes of defects and methods by which to reduce these defects stemming from molten metal flows in a runner system of the type widely used in the sand mold casting process. The flow characteristics of a molten alloy are difficult to observe during the actual casting process. For this reason, a water model was used to observe the flow in the casting process, and the flow in each case was recorded using high-speed cameras as part of the experimental process of this study. Several repetitive experiments were performed to improve the accuracy of the experimental results. The traditional casting system was modified according to the design rules proposed by Campbell, and the system was termed flow-adaptive gating system with a water model. Comparing the flow characteristics of traditional and adaptive gating systems with a water model shows that the bubbles in the water in the latter case are reduced more significantly than in the former case. A ceramic filter system was adapted to the flow-adaptive gating system to minimize the instability of the flow during filling, which occurs as the fluid velocity in the runner increases. In additional, the flow behavior with and without the filter system were compared. The water model system in this work was shown to be able to verify that the adaptation of the filter system brings improvements by stabilizing the flow and reducing the amount of bubbles in the runner system. Moreover, using the flow-adaptive runner system with the filter system leads to considerably stable flows in the runner system.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.98.5-98
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• 2001

An efficient adaptive nonlinear compensator, based on a wavelet transform domain adaptive Volterra filter along with a modified escalator algorithm, is proposed to speed up the convergence rate of an adaptive LMS algorithm. In particular, it is well known that the e.g., slow convergence speed of an adaptive LMS algorithm depends on the statistical characteristics (e.g., large eigenvalue spread) of the corresponding auto-correlation matrix of the input vector. To solve such a convergence problem, the proposed approach utilizes a modified escalator algorithm and a wavelet transform domain adaptive LMS Volterra filtering technique, which leads to diagonalization of the auto-correlation matrix of the ...

• The Journal of Korean Institute of Communications and Information Sciences
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• v.10 no.5
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• pp.258-265
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• 1985

A design method for a single-input single-output discrete time model reference adaptive system is described in this paper. By using the state-variable filters into inputs and outputs in reference model and unknown system, a simple adaptive structure which use all accessible signals can be constructed. Some papers for the adaptive shstem is which thw relative degree of unknown system have one or two have been reported, but the resulting adaptive system are intricate in structures and the design theories for the model reference adaptive system are not generalized. In this paper, for having two or more relative degrees, it has been verified that an adaptive scheme can be obtained by introducing a simple linear filter.

• The Journal of the Acoustical Society of Korea
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• v.24 no.5
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• pp.238-247
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• 2005

In this Paper. we Presents subband design techniques of a compensating filter and adaptive feedback canceller for the digital hearing aid. The sensorineural hearing loss has a hearing threshold that shows a nonlinear characteristic in frequency domain. and its compensation suffers from an echo that produced by an undesired time varying feedback path. Therefore. the digital hearing aid requires the compensator that can adjust gains nonlinearly in frequency bands and eliminate the echo rapidly In the Proposed digital hearing aid. the compensating filter is designed by the adaptive system identification method in subband structure, and the adaptive feedback canceller is designed by the subband affine projection algorithm. The designed compensation filter can control the nonlinear gain in each subband respectively, therefore precise compensation is possible. And the feedback canceller using the subband adaptive filter achieves fast convergence rate. The Performances of the Proposed method are verified by computer simulations as comparing with the behaviors of the previous trials.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2000.04b
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• pp.365-370
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• 2000

A sliding mode fuzzy control (SMFC) algorithm is applied to design a controller for a benchmark problem on a wind- excited building. The structure is a 76-story concrete office tower with a height of 306 meters, hence the wind resistance characteristics are very important for the serviceability as well as the safety. A control system with an active tuned mass damper is assumed to be installed on the top floor. Since the structural acceleration is measured only at ,limited number of locations without measurement of the wind force, the structure of the conventional continuous sliding mode control may have the feed-back loop only. So, an adaptive least mean squares (LMS) filter is employed in the SMFC algorithm to generate a fictitious feed-forward loop. The adaptive LMS filter is designed based on the information of the stochastic characteristics of the wind velocity along the structure. A numerical study is carried out. and the performance of the present SMFC with the ,adaptive LMS filter is investigated in comparison with those of' other control, of algorithms such as linear quadratic Gaussian control, frequency domain optimal control, quadratic stability control, continuous sliding mode control, and H/sub ∞///sub μ/, control, which were reported by other researchers. The effectiveness of the adaptive LMS filter is also examined. The results indicate that the present algorithm is very efficient .

• The Journal of Korean Institute of Communications and Information Sciences
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• v.16 no.12
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• pp.1219-1228
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• 1991

In the actual case, a model of noise canceller using adaptive filter has both a channel transfer function from noise source to main signal input and to noise canceller input. The previous models of noise canceller have been considered to be only one side channel transfer function. Therefore, it is proposed that a new model has two channel transfer functions and derives an optimal tranfer function of adaptive noise canceller. The adaptive filter is using the joint process lattice filter that has fast adaptive speed. The signal noise radio has been improved by a model of ANC-ALE and it is confirmed with computer simulation. Beside, a dc bias is very effective for noise cancelling, especially to the particular signal.

• Proceedings of the KIEE Conference
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• 2005.10b
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• pp.17-19
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• 2005

In this paper, using B-splines as universial approximators, we have obtained a plant parametrization which permits the construction of an adaptive observer. The particular property of this parametrization is that the dynamic order of the filters in this design does not depend on the number of parameters in the plant parametrization. This appears to be a beneficial property especially because the number of such parameters tends to be very high for universial approximator based designs.