• Journal of the Korea Convergence Society
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• v.6 no.5
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• pp.233-240
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• 2015

In this paper, we present an algorithm that estimates the speed of a moving object only using its sound information. In general, the speed gun projects the incident light onto a moving object and measures the frequency variation of the scattered light. Then the speed is measured by this frequency difference. In our study, instead of light information, we measure the speed by sound frequency difference when the object is coming and moving away. In our experiments on the speed measurement, on average the error of 6.08% was obtained. Utilizing this algorithm for smart device, we can measure the speed of a moving object without sensor that measures the frequency of the light.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.8
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• pp.1777-1783
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• 2013

We do research on the simulation of Doppler effect from a target's moving under the sea by Transmission Line Matrix modeling which is one of numerical methods on time domain. To implement the effect, the input signal was entered at a moving node according to a moving target's moving speed. The result had maximum 2.47% error compared with the theoretical value. And from simulation results with speed control of a moving target, we could also obtain resonable results within 0.63% error range.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.1
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• pp.33-41
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• 2017

This paper suggests a hand gesture recognition technology to control smart devices using multiple Doppler radars and a support vector machine(SVM), which is one of the machine learning algorithms. Whereas single Doppler radar can recognize only simple hand gestures, multiple Doppler radar can recognize various and complex hand gestures by using various Doppler patterns as a function of time and each device. In addition, machine learning technology can enhance recognition accuracy. In order to determine the feasibility of the suggested technology, we implemented a test-bed using two Doppler radars, NI DAQ USB-6008, and MATLAB. Using this test-bed, we can successfully classify four hand gestures, which are Push, Pull, Right Slide, and Left Slide. Applying SVM machine learning algorithm, it was confirmed the high accuracy of the hand gesture recognition.

• Journal of radiological science and technology
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• v.37 no.2
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• pp.117-124
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• 2014

This study has investigated the effects of the defects in the probe elements influence Doppler images in the medical ultrasonic scanners. This work was implemented that the quality of Doppler images depended on the extent and location of the probe element defected. The probe performance was rated in terms of the number of piezoelectric elements lost and this was studied in the experiment by electrical disconnection to the elements. The results showed that Doppler velocity became rapidly reduced as the defected elements encountered with the element group activated at the Doppler mode, not as the flow velocity. The effect of the probe defect is decreased when the defects occurred at the element group activated for Doppler mode, as was increased the number of the elements. It was observed that the higher the flow velocity of Doppler flow phantom is, the wider the spectrum of Doppler is. And the Doppler velocity soared up and the dispersion of image brightness is increased when the defected elements got out of the elements activated at Doppler mode. The result showed that TADVP(time-average-Doppler-velocity-profile) is decreased with the increase of the probe element defect, especilly in the region of high frequency. It is expected that the research of various defects of probe elements are needed, and this study can be practical tools for probe based ultrasonic QA in the future.

• Journal of Sensor Science and Technology
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• v.3 no.2
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• pp.57-64
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• 1994

This paper describes the measurement of tissue blood flow by the the self-mixing effect of laser diode. A Laser doppler signals due to the moving object and the tissue blood flow were detected by the self-mixing effect of laser diode. The Doppler shifted frequency was changed linearly with the driving frequency of moving object and was increase after the exercise. The results of in-vivo experiment were consistent with the result of exercise physiology.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.4
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• pp.857-864
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• 1998

The infuluence of Doppler effects on the tracking performance of a noncoherent second-order delay locked loop (DLL) operating on a data modulated signal is investigated. For the perfoermance analysis we consider the tracking accuracy (steady state error and jitter) of the linear DLL and the reliability of the nonlinear loop. The nonlinear analysis concerning the loop reliability makes use of an asympototic expansion for the MTLL(mean time to lose lock) which has been derived by applying the singular perturbation method. In particular, we give optimal loop parameters and the optimal bandwidth of the bandpass filter in the loop arms to achieve a maximum MTLL. Since Doppler effects can be producesd comparatively in LEO system, we can espect the more reliable DLL loop design. by using the results of the circuit simulation, the delay lock loop is synthesized in FPGA, and verified to get the GPS data from the STR-2770 GPS simulator system. So, the synthesized logic circuit is shown be accurately performed.

• Journal of Advanced Navigation Technology
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• v.23 no.2
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• pp.142-150
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• 2019

Muzzle Velocity is one of the most important measurement items for evaluation of ammunition. The muzzle velocity is defined as the velocity when the projectile leaves the muzzle. Particularly, since the muzzle velocity is closely related to the performance of the propellant, precise measurement of muzzle velocity is required. Doppler radar is used to measure the muzzle velocity, but the quality of Doppler radar signal depends on the test site environment. In this paper, a method to remove the clutter that degrades the signal quality of Doppler radar by improving the structure of the test site and the signal processing method is suggested. For the application of the improved signal processing method, a program for acquiring Doppler radar's raw Doppler data was created. Statistical verification of the velocity data obtained through the improvement of the test site structure and signal processing method proved that the proposed method is effective for the removal of clutter as compared with the existing method.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.5
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• pp.431-437
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• 2013

Measured acoustic signal from operating high speed train contains frequency change called doppler shift due to its motion. To avoid this doppler shift wind tunnel test is required. But scaledown of model can cause change of source characteristics. And measurements using some part of train cannot reproduce real flow condition. The best way to recognize real noise source characteristics is measurement from operating high speed train but doppler shift makes it hard. So, we developed simple dedopplerization technique for one microphone and applied to field test data of high speed train. Through this, we could capture real frequency of noise from operating high speed train.

• Korea Science and Art Forum
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• v.30
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• pp.367-376
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• 2017

This study introduces conducting practice tool for conducting majoring students. There have been various types of related research, but most of them have not been optimized for the conducting major. In addition, we thought that it would be a tool to be able to carry like a musical instrument in order to practice conducting without restriction of place and time. And also, it will be one of the few tools to focus on queuing. The practice tool presented in this study use the Doppler effect to overcome the limitations of previous studies. It was concluded that the Doppler method, which is highly compatible, simple, and accurate, is superior to motion detection methods using existing sensors. It is expected that it will be used not only as a conducting but also as an interaction tool of various media.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.7 no.1
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• pp.71-82
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• 1996

In this paper, the Doppler phase error due to the relative velocity between a satellite and the earth station in communications using a low earth orbit mobile satellite is detected. The performance of BPSK system in the presence of Rician fading with Doppler phase error and interference, noise is compared with that of the system disturbed by Doppler phase error and noise only. The expression of error rate performance of BPSK system is derived as the type of complementary error function. The numerical calculation of the induced equation are performed in terms of satellite-height, orbit-eccentricity, the velocity of the earth, Rician fading parameter, signal to interference rateio (SIR), the ratio of carrier frequency and base band bit rate. The main conclusion that can be drawn from this analysis is that Rician fading channel environment with Doppler phase error and interference effect yields severe performance degradation than Do- ppler phase error and noise effect in satellite communication channel. And using the numerical calculation, we give a quantitative insight how much the satellite communication channel parameters degrade the system performance. Furthermore it is shown that an appropriate transmission power control for the performance enhancement is beneficial to the new satellite communication system planning.