• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.6
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• pp.603-608
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• 2011

Since PTV (particle tracking velocimetry) provides velocity vectors by tracking each particle in a fluid flow, it has significant benefits when used for nano- and bio-fluid flows. However, PTV has only been used for limited flow fields because interpolation data loss is inevitable in PTV in principle. In this paper, a hybrid particle image velocimetry (PIV) algorithm that eliminates interpolation data loss was constructed by using an affine transformation. For the evaluation of the performance of the constructed hybrid PIV algorithm, an artificial image test was performed using Green-Taylor vortex data. The constructed algorithm was tested on experimental images of the wake flow (Re = 5,300) of a rectangular body ($6cm\;{\times}3cm$), and was demonstrated to provide excellent results.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1993.10a
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• pp.582-586
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• 1993

• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.127-130
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• 1999

본 논문에서는 수신된 CW 신호로부터 Morse 코드를 자동 인식하는 알고리듬을 제안하였다. 전체 알고리듬은 수신된 CW 신호로부터 잡음 및 간섭신호 성분을 제거하고 신호의 존재유무를 판정하는 부분, 신호 길이의 변화를 극복하여 Morse 코드의 요소(Long, Short, Null set)로부터 코드로 판독하는 부분으로 구성되었다. 제안된 알고리듬은 CW 신호의 주파수, 위상 및 길이 정보가 필요 없으며, 모의 실험 결과, SNR -15dB, $20\%$의 신호 길이 변화 환경에서도 $100\%$의 해석률을 나타내었다.

• The Journal of the Acoustical Society of Korea
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• v.18 no.7
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• pp.23-32
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• 1999

This paper presents a stochastic convergence analysis of LMS algorithm and VS-LMS algorithm for IIR filters using equation error formulation. Under the assumption that the signal is white Gaussian, theoretical equations that characterize the mean and mean-squared behaviors of the algorithms are derived. Computer simulation results show fairly good agreements between the theoretical and the empirical behaviors of the algorithms.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.3
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• pp.232-239
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• 1992

In this paper, an analytical expression of the excess MSE of ITLMS(Individual Tap LMS) which results from the random fluctuation of the distance between the actual and optimal coefficients due to noisy gradient estimates, is derived. The expression reveals that the excess MSE of the ITLMS algorithm is smaller that that of the LMS algorithm. The performance of the algorithm from the computer simulation for a fading time-dispersive channel verifies the theoretical results.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.4B
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• pp.447-456
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• 2001

본 논문에서는 DS-확산대역 시스템에서 격자형 IIR 노치필터를 이용하여 협대역 간섭신호를 제거한다. 이를 위하여 우선 갑섭신호의 주파수와 파워가 격자형 IIR 노치필터에 의ㅏ형 추정된다. 그리고 또 다른 IIR 노치필터를 수긴기 닾에 위치시키고 노치의 위치가 추정된 갑섭신호의 주파수에 있도록 한다. 그러나 단워원 위에 영점이 존재하는 IIR 노치필터는 간섭신호 뿐만 아니라 노치부분의 신호 성분도 제거하므로 데이터의 왜곡이 발생하게 된다. 따라서 이러한 데이터의 왜곡을 줄이기 위해서 필터의 노치 깊이를 조절하는 알고리듬을 개발하였다. 이를 위해 노치필터 출력의 신호 대 잡음비를 필터 파라미터에 대한 식으로 유도하고 이를 최대로 하는 최적의 노치 깊이를 구하였다. 시뮬레이션 결과 제안한 알고리듬이 기존의 FIR 노치필터나 FIR LMS 알고리듬에 비해 좋은 성능을 갖는다는 것을 확인할 수 있다.

• Journal of Institute of Control, Robotics and Systems
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• v.3 no.6
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• pp.563-568
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• 1997

본 논문에서는 약간의 가정하에 리모트 제어용 모형 헬리콥터의 동역학방정식을 유도하였으며, 이를 토대로하여 헬리콥터의 자세안정을 위한 제어 알고리듬을 제안하였다. 제어이론으로서는 파라메타의 변화및 외란에 강인한 가변구조 제어이론을 활용하였다. 본 제어 알고리듬에서는 헬리콥터의 위치이동 제어에 대하여서는 다루지를 못하였으며, 단지 헬리콥터의 hovering 상태에서의 자세 안정화에만 촛점을 두어 제어 알고리듬을 제안하였다. 컴퓨터 모사를 통하여, 제안된 제어 제어 알고리듬의 타당성을 보였으며, 약 2-3초의 시간이 경과된 이후 자세가 안정화 됨을 볼 수 있었다.

• Journal of the Institute of Convergence Signal Processing
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• v.8 no.2
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• pp.106-112
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• 2007

This paper proposes a hybrid architecture algorithm for fast computation of DCT and DFT via recursive factorization. Recursive factorization of DCT-II and DFT transform matrix leads to a similar architectural structure so that common architectural base may be used by simply adding a switching device. Linking between two transforms was derived based on matrix recursion formula. Hybrid acrchitectural design for DCT and DFT matrix decomposition were derived using the generation matrix and the trigonometric identities and relations. Data flow diagram for high-speed architecture of Cooley-Tukey type was drawn to accommodate DCT/DFT hybrid architecture. From this data flow diagram computational complexity is comparable to that of the fast DCT algorithms for moderate size of N. Further investigation is needed for multi-mode operation use of FFT architecture in other orthogonal transform computation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.12
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• pp.2386-2396
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• 1994

In this paper, an optimal algorithm for the design of 1-D FIR filters with finite precision coefficients is proposed. The algorithm is based on the observation that the frequency constraints of a sub-problems(SP) in the branch and bound algorithm, which repeatedly use LP(linear programming), are closely related with those of neighboring SPs. By using the relationship between the SPs, the proposed algorithm reduces the number of constraints required for solving each SP with Lp, whereas the conventional algorithm employs all the constraints, which are required for solving the initial problem. Thus, the overall computational load for the design of FIR filters with finite precision coefficients is significantly alleviated, compared to the conventional branch and bound algorithm. Also, a new branching scheme for the design of FIR filters with sum-of-power-of-two(SOPOT) coefficients is proposed. It is shown that the computational load for the design fo SOPT coefficient filters can be further reduced with the new branching scheme.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.5
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• pp.373-382
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• 2013

In this paper, in order to analyze the performance of a decoy system for ship defense against an anti-ship missile(ASM) with an infrared image(IIR) seeker, the modeling and engagement simulation program is introduced. The IIR seeker on the ASM detects the infrared signal of ship from a distance and approaches the ship based on proportional navigation guidance(PNG) or impact angle control guidance(IACG). Hence the guidance performance of the ASM is basically depend on the target tracking algorithm of the seeker as well as the infrared signal of the ship. Using the developed program, we can investigate the effect of the ship decoy system such as flares and surface cooling system of the ship with respect to various kinds of tracking algorithms of the IIR seeker of the ASM.