• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.10
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• pp.181-186
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• 2012

In this paper, we describe the synthesis of robust and non-fragile Kalman filter design for a class of uncertain linear system with polytopic uncertainties and filter gain variations. The sufficient condition of filter existence, the design method of robust non-fragile filter, and the measure of non-fragility in filter are presented via LMIs(Linear Matrix Inequality) technique. And the obtained sufficient condition can be represented as PLMIs(parameterized linear matrix inequalities) that is, coefficients of LMIs are functions of a parameter confined to a compact set. Since PLMIs generate infinite LMIs, we use relaxation technique, find the finite solution for robust non-fragile filter, and show that the resulting filter guarantees the asymptotic stability with parameter uncertainties and filter fragility. Finally, a numerical example will be shown.

• Journal of KIISE:Software and Applications
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• v.37 no.10
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• pp.751-759
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• 2010

This paper is to propose a method to enhance the connectivity of the broken structures. The pixels to be connected are found by a decision rule which is based on the intensity and gradient information of the neighboring pixels. The intensity of the pixel, if it is decided to be filled, is increased so that the pixel together with its neighbors looks connected. The anisotropic diffusion follows to make the connected structural region look more natural. The same structure matrices have been used both to get gradient information and to decide the direction of diffusion to improve the computational speed. It has been shown by the experiments on the real ultrasound images that the broken structural regions can be connected by the proposed method.

• Proceedings of the IEEK Conference
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• 2001.09a
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• pp.769-772
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• 2001

Waish-Hadamard Transform은 압축, 필터링, 코드 디자인 등 다양한 이미지처리 분야에 응용되어왔다. 이러한 Hadamard Transform을 기본으로 확장한 Jacket Transform은 행렬의 원소에 가중치를 부여함으로써 Weighted Hadamard Matrix라고 한다. Jacket Matrix의 cocyclic한 특성은 암호화, 정보이론, TCM 등 더욱 다양한 응용분야를 가질 수 있고, Space Time Code에서 대역효율, 전력면에서도 효율적인 특성을 나타낸다 [6],[7]. 본 논문에서는 Distributed Arithmetic(DA) 구조를 이용하여 Fast Jacket Transform(FJT)을 구현한다. Distributed Arithmetic은 ROM과 어큐뮬레이터를 이용하고, Jacket Watrix의 행렬을 분할하고 간략화하여 구현함으로써 하드웨어의 복잡도를 줄이고 기존의 시스톨릭한 구조보다 면적의 이득을 얻을 수 있다. 이 방법은 수학적으로 간단할 뿐 만 아니라 행렬의 곱의 형태를 단지 덧셈과 뺄셈의 형태로 나타냄으로써 하드웨어로 쉽게 구현할 수 있다. 이 구조는 입력데이타의 워드길이가 n일 때, O(2n)의 계산 복잡도를 가지므로 기존의 시스톨릭한 구조와 비교하여 더 적은 면적을 필요로 하고 FPGA로의 구현에도 적절하다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.5
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• pp.649-655
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• 2022

In this paper, a determinant-based two-channel noise reduction method which utilizes speech presence probability (SPP) is proposed. The proposed method improves noise reduction performance from the conventional determinant-based two-channel noise reduction method in [7] by applying SPP to the Wiener filter gain. Consequently, the proposed method adaptively controls the amount of noise reduction depending on the SPP. For performance evaluation, the segmental signal-to-noise ratio (SNR), the perceptual evaluation of speech quality, the short time objective intelligibility, and the log spectral distance were measured in the simulated noisy environments considered various types of noise, reverberation, SNR, and the direction and number of noise sources. The experimental results presented that determinant-based methods outperform phase difference-based methods in most cases. In particular, the proposed method achieved the best noise reduction performance maintaining minimum speech distortion.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.13 no.4
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• pp.322-331
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• 1988

In this thesis, an active RC filter using high order inverse chebyshev function is designed and the design method for cascading blocks with low sensitivity and maximum dynamic range is discussed. To have maximum dynamic range, we have proposed the simple algorithm with a pole-zero pairing, the cascading sequence by flatness matrix and optimum gain distribution for a given transfer function. And 2nd order Block is designed with negative feedback to improve the sensitivity problem which had a defect at active RC circuits. Using the suggested method, we have designed the active RC low pass filter of the normalized 7th order inverse chebyshev function, as a results, we have shown that this accord with the given specification.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.4
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• pp.591-598
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• 2021

The digital phase-locked loops(DPLL) is a circuit used for phase synchronization and has been generally used in various fields such as communication and circuit fields. State estimators are used to design digital phase-locked loops, and infinite impulse response state estimators such as the well-known Kalman filter have been used. In general, the performance of the infinite impulse response state estimator-based digital phase-locked loop is excellent, but a sudden performance degradation may occur in unexpected situations such as inaccuracy of initial value, model error, and disturbance. In this paper, we propose a minimum variance finite impulse response filter with optimal horizon for designing a new digital phase-locked loop. A numerical method is introduced to obtain the measured value interval length, which is an important parameter of the proposed finite impulse response filter, and to obtain a gain, the covariance matrix of the error is set as a cost function, and a linear matrix inequality is used to minimize it. In order to verify the superiority and robustness of the proposed digital phase-locked loop, a simulation was performed for comparison and analysis with the existing method in a situation where noise information was inaccurate.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.9
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• pp.863-871
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• 2004

In this paper, we propose a subspace channel estimation technique for DS/CDMA DMB down link system, which can obtain reduction in numerical complexity by using of matched filtering outputs. The complexity reduction is considerable when the channel length is small and the system is moderately loaded. Previously proposed subspace-based blind channel estimation algorithm suffer from high numerical complexity for systems with large spreading gains. Although the proposed algerian suffers a slight performance loss, it becomes negligible for large observation length. Performance is evaluated through simulations and the derivation of the analytical MSE.

• Journal of IKEEE
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• v.25 no.4
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• pp.762-765
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• 2021

In this paper, an automotive ECU (electronic control unit) with Kalman filter accelerator is designed and implemented. RISC-V is exploited as a processor core. Accelerator for Kalman filter matrix operation, CAN (controller area network) controller for in-vehicle network, and LIN (local interconnect network) controller are designed and embedded. Kalman filter operation consists of time update process and measurement update process. Current state variable and its error covariance are estimated in time update process. Final values are corrected from input measurement data and Kalman gain in measurement update process. Usually floating-point multiplication is exploited in software implementation, but fixed-point multiplier considering accuracy analysis is exploited in this paper to reduce hardware area. In 28nm silicon fabrication, its operating frequency, area, and gate counts are 100MHz, 0.37mm², and 760k gates, respectively.

• Journal of the Korea Institute of Military Science and Technology
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• v.12 no.4
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• pp.540-547
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• 2009

In the near future, military robots are likely to be substituted for military personnel in the field of battle. The power system of a legged robot is considerably more complex than the one used for a land vehicle because of the coordination and stability issues due to the large number of degree of freedom. In this paper, a servovalve-piston combination system for a straight-line motion of robot leg is modeled as three degree of freedom based on double inputs and single output transfer function. The output is the displacement of piston from neutral. The inputs are valve displacement from neutral and arbitrary load force in this system. LQR(Linear Quadratic Regulator) technique is applied in order to achieve robust stability and fast responses of the system. The Kalman filter loop, rejection of disturbance and noise, riccati equation, filter gain matrix, and frequency domain equality are analyzed and designed.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.2
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• pp.237-244
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• 2020

This paper describes an implement of Simultaneous Localization and Mapping(SLAM) in two dimensional space. The method uses Invariant Extended Kalman Filter(IEKF), which transforms the state variables and measurement variables so that the transformed variables constitute a linear space when variables called the invariant quantities are kept constant. Therefore, the IEKF guarantees convergence provided in the invariant quantities are kept constant. The proposed IEKF approach uses Lie group matrix for the transformation. The method is tested through simulation, and the results show that the Kalman gain is constant as it is the case for the linear Kalman filter. The coherence between the estimated locations of the vehicle and the detected objects verifies the estimation performance of the method.