• Geophysics and Geophysical Exploration
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• v.3 no.4
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• pp.119-124
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• 2000

A new fast algorithm for travel time calculation using mono-chromatic one-way wave equation was developed based on the delta function and the logarithms of the single frequency wavefield in the frequency domain. We found an empirical relation between grid spacing and frequency by trial and error method such that we can minimize travel time error. In comparison with other methods, travel time contours obtained by solving eikonal equation and the wave front edge of the snapshot by the finite difference modeling solution agree with our algorithm. Compared to the other two methods, this algorithm computes travel time of directly transmitted wave. We demonstrated our algorithm on migration so that we obtained good section showing good agreement with original model. our results show that this new algorithm is a faster travel time calculation method of the directly transmitted wave for imaging the subsurface and the transmission tomography.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1763-1766
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• 2003

Millimeter-wave networking is composed of narrow beam link. it is very substantial that beam connecting point to point is fixed in right direction. It is major requirement in the beam network to keep the beam in best direction. In this paper, We propose the method to find a best suited direction of the antenna's beam using the Genetic Algorithm (GA) in point-to-point link. Proposed method presume that each station knows his direction ${\theta}_1$ , ${\theta}_2$ at every step of GA, then it can be expected that GA is possible to search the ideal solution. Intensity of the received signal is evaluated by the multiplication of lengths to the point which the lobe meets with the horizontal line.

• Journal of IKEEE
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• v.8 no.2 s.15
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• pp.161-165
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• 2004

In this paper, an 8bit wave pipelined adder using the static CMOS plus Edge-Sensing Completion Detection Logic is presented. The clockless wave-pipelining algorithm was implemented in the circuit design. The Edge-Sensing Completion Detection (ESCD) in the algorithm is consisted of edge-sensing circuits and latches. Using the algorithm, skewed data at the output of 8bit adder could be aligned. Simulation results show that the adder operates at 1GHz in $0.35{\mu}m$ CMOS technology with 3.3V supply voltage.

• Proceedings of the KOSOMBE Conference
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• v.1998 no.11
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• pp.213-214
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• 1998

The important role of the ultrasonic Doppler system in the modem clinical medicine is to provide the clinical information of the vascular system. The ultrasonic pulsed wave(PW) Doppler system, a kind of the ultrasound Doppler system, is more available than the ultrasonic continuous wave(CW) Doppler system because it can evaluate the velocity and the direction of blood flow as well as the depth of vessel. However, the ultrasonic PW Doppler system has the disadvantage that the range of evaluating velocity of blood flow is limited(Nyquist limit). In order to solve this limit, we propose the algorithm for eliminating this aliasing in this paper. In addition, we propose the efficient signal processing algorithm.

• Journal of Biomedical Engineering Research
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• v.6 no.2
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• pp.53-62
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• 1985

The position and time interval of wave components of the electrocardiogram are used as important data for physician's diagnosis. In case of using the existing definition of the onset of the wave component of the electrocardiogram, they have some problems of defining the precise position of the isoelectric line, of defining the limit of the gradient accepted as the onset, and of the gradient being changed by noise. Therefore, in this paper all time intervals and positions of wave components needed for data of diagnosis were obtained correctly by turning point data reduction algorithm and linear regression intersection algorithm, and the viability of the method of intersecting lines was established in comparison to the four methods of calculating the PR interval.

• Proceedings of the KOSOMBE Conference
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• v.1995 no.05
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• pp.186-189
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• 1995

This paper performed P wave detection algorithm for diagnosis in according to method of cardiologist's P wave detection. We used correlation pattern matching for prominent P waves and P-P interval estimation for ambiguous P waves. Results of this study indicate that this algorithm has potential for improving P wave detection performance.

• Journal of Mechanical Science and Technology
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• v.19 no.12
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• pp.2263-2269
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• 2005

The ship wave phenomena in the restricted waterway were investigated by a numerical analysis. The Euler and continuity equations were employed for the present study. The boundary fitted and moving grid system was adopted to enhance the computational efficiency. The convective terms in the governing equations and the kinematic free surface boundary condition were solved by the Constrained Interpolated Profile (CIP) algorithm in order to solve accurately wave heights in far field as well as near field. The advantage of the CIP method was verified by the comparison of the computed results by the CIP and the Maker and Cell (MAC) method. The free surface flow simulation around Wigley hull was performed and compared with the experiment for the sake of the validation of the numerical method. The present numerical scheme was applied to the free surface simulation for various canal sections in order to understand the effect of the sectional shape of waterways on the ship waves. The wave heights on the side wall and the shape of the wave patterns with their characteristics of flow are discussed.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.5
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• pp.242-250
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• 2013

In this paper, R-wave detection algorithm using refractory period to reflect the depolarization and repolarization of the myocardial cells of the heart is proposed. The proposed algorithm detects R-peaks using the features of R-wave and variable refractory period. First, the proposed algorithm extracts candidate R-peaks that have a relatively high potential and calculates the refractory period based on the kurtosis and potential for candidate R-peaks. Next, R-peak is determined by morphological features of the R-wave within the refractory period. In addition, due to less computation in the proposed algorithm, real-time processing is possible. The algorithm is applied to all records of the MIT-BIH arrhythmia database and the obtained results show a competitive detection rate of over 99.7%.

• Communications of the Korean Mathematical Society
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• v.16 no.3
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• pp.509-518
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• 2001

The purpose of this paper is to propose a numerical algorithm for the problem of coefficient identification of the scalar wave equation based on a local observation on the boundary: Determine the unknown coefficient function with the knowledge of simultaneous Dirichlet and Neumann boundary values on a part of boundary. To find the unknown coefficient function, the unknown Neumann boundary value is also identified. We recast our inverse problem to variational problem. The gradient method is applied to find the minimizing functions. We confirm the effectiveness of our algorithm by numerical experiments.

• The Journal of the Acoustical Society of Korea
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• v.36 no.4
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• pp.273-278
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• 2017

In this paper, a post-processing algorithm to suppress reverberation for continuous-wave active sonar system is developed. The developed algorithm is designed for a low-doppler environment where the target echo is not distinguishable from the reverberation. The algorithm is developed based on overlapping nonnegative matrix factorization method. The algorithm analyzes the frequency characteristics of transmitting ping signal, then suppresses the reverberation using time-frequency characteristics of the received signal. Simulations performed in order to evaluate the proposed algorithm, and the results show that the proposed algorithm makes 6 dB signal-to-reverberation ratio enhancement in various reverberation energy conditions.