• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.12
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• pp.1105-1111
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• 2016

In modern warfare, various target tracking radars are used for target location tracking. So, the importance of EA radar jamming technique which disrupt enemy target tracking radar in oder to neutralize tararget location tracking has increased. VGPO/I jamming is a base technique of EA(Electronic Attack), it is possible to operate to pulse-Doppler radar. In this papar, we develop VGPO/I jamming technique that can apply to phase sampled DRFM by using phase information and verifiy through simulations.

• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.269-272
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• 2000

수중 표적으로부터 수신된 신호에서, 파도와 난류 등의 영향으로 선박의 특정 기계류들의 부하변동과 도플러효과 등에 의해 야기되는 특징 주파수의 시간적 변동과 같은 음향 특징 추출은 수중음향 신호처리에서 중요한 연구분야이다. 본 연구에서는 이들의 발생기구 해석을 기초로 효과적인 분석 추적 기법을 제시한다.

• Clinical and Experimental Pediatrics
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• v.49 no.4
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• pp.417-423
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• 2006

Purpose : The objectives of this study were to assess ventricular function by tissue Doppler imaging in children who were receiving chemotherapy or who had received chemotherapy, and to apply repeated tissue Doppler imaging to make an early assessment in cardiac toxicity studies. Methods : This study was conducted on 23 oncology patients on-treatment or off-treatment from April 2005 to July 2005 at Dongsan Medical Center, Keimyung University. All patients(group 1) were divided into two groups, fractional shortening(FS) over 29 percent(group 2) and FS under 28 percent (group 3) in the first category. These same patients were also divided into the following groups : group treated with anthracyclin(group 4) and group treated without anthracyclin(group 5). Deceleration time(DT), isovolumic relaxation time(IVRT), FS, peak early diastolic(E), and peak late diastolic (A) velocity of transmitral flow were measured by M-mode and pulsed wave Doppler. Systolic(Sm), peak early diastolic(Em), and peak late diastolic(Am) velocity in apical 4-chamber and 2-chamber views were measured by tissue Doppler imaging. The author calculated a modified Tei index, E/A, E/Em ratio by using measured values. Results : Twenty three patients were enrolled : 12 boys and 11 girls. The average age of patients was 8 years and 4 months. Thirteen out of 23 patients were in the group treated with anthracyclin (group 4) and 6 had FS under 28 percent(group 3). E/Em ratio showed a significant difference between group 1 and control group($6.46{\pm}1.85$ vs $7.06{\pm}1.64$, P<0.05). Other parameters had no difference statistically. Conclusion : This study showed that the change of cardiac function developed earlier in diastolic function than in systolic function, as E/Em ratio reflecting the mean LV diastolic pressure showed a significant difference between the control group and chemotherapy groups. Echocardiography using tissue Doppler imaging is a non-invasive, comfortable and reliable method for post-chemotherapy follow up.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.11
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• pp.1973-1977
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• 2006

This paper reports the absolute position tracking algorithm of underwater vehicles such as ROV, AUV in global region by fusing sensor informations of IMU, DVL, USBL, DGPS etc. This algorithm is to be used in the position tracking of the 6,000m class deep-sea unmanned underwater vehicle, HEMIRE for scientific exploration.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.1
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• pp.6-14
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• 1996

In this paper we present an algorithm to discriminate an underwater target under track against an acoustic counter-measure(ACM) source, based on a sequential hypothesis test. The ACM source is separated from the target under track and generates, while drifting, measurements with false range and Doppler information. The purpose of the ACM is to mislead the target-tracking and to help the true target evade a pursuer. The algorithm uses as a test statistic a function of the innovation sequences from extended Kalman filters to estimate the target dynamics and the drifting position of the ACM source. Numerical experiments on various scenarios show that the proposed algorithm discriminates the target against an ACM source very fast with a high probability of success.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.12
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• pp.77-84
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• 2005

The orthogonal frequency division multiplexing (OFDM) technique and the single carrier with cyclic prefix (SC-CP) scheme are very attractive solutions for wireless applications, being computationally efficient since equalization is performed in the frequency domain. The equalizer could not entirely handle significant mean. Doppler shift. This motivates the use of a phase error tracking loop that operates jointly with the frequency equalizer. This paper describes the effect of the mean phase error and the performance of the proportional equalizer coupled with a phase error tracking loop based on decision-directed method. Furthermore, simulation results show that we can reduce the computational toad of the tracking loop with minimal performance degradation.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.2 no.4
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• pp.17-27
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• 2003

This paper presents the channel estimation method with STBC applied to IEEE802.11a. Tenacious channel estimation method for OFDM system, that generally uses STTC, has been presented once and massive amount of calculation was needed However, regarding this paper, the amount of calculation can be reduced by using Curve Fitting, and channel tracking performance improvement can be achieved Based on the estimation method, computer simulation was done for the performance analysis and delay spread Doppler frequency and many other group sizes and numbers were considered As a result of the testing, we found out that Doppler frequency deviation effects equally as frequency offset. Also compared to the existing technique, channel estimated performance confirmed that have 0.9dB SNR improvement than old method.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.6
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• pp.580-588
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• 2009

A Missile Warning Radar is an essential sensor for active protection system to detect antitank missile in all weather environments. This paper presents the design, development, and test results of L-band pulsed Doppler radar system for main battle tank. This radar system consists of 3 LRUs, which include antenna unit, transmitter and receiver unit and radar signal & data processing unit. The developed core technologies include the patch antenna, SSPA transmitter, coherent I/Q detector, DSP based Doppler FFT filter, adaptive CFAR, SIW tracking capability, and threat decision. The design performance of the developed radar system is verified through various ground fixed and moving vehicle test.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.5
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• pp.71-77
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• 2020

Recently, the tracking radar has confirmed the necessity of developing a small tracking radar that can be operated without various restrictions in various environments. In addition, the performance of a small tracking radar requires equal to or higher than the existing tracking radar. Such a small tracking radar can be implemented through miniaturization and low power of existing tracking radar. In this paper, the role and function of a signal processor for a small tracking radar are defined and we proposed a method to increase the efficiency of power consumption and miniaturization by minimizing the use of devices required to implement a signal processor for a small tracking radar. Used as a method for miniaturization, a device processor such as DDC and communication controller was implemented in an FPGA to design a signal processor for a small tracking radar. In addition, a low-power signal processor was designed by a power supply using a highly efficient switching regulator. Finally, the signal processor was verified by the performance test of the signal processor for the small tracking radar implemented, the Doppler tracking test using the signal processor on the small tracking radar, and the distance tracking test.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.8 s.111
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• pp.773-787
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• 2006

An airborne radar is an essential aviation electronic system for the aircraft to perform various civil and/or military missions in all weather environments. This paper presents the design, development, and test results of the multi-mode X-band pulsed Doppler radar system test model for helicopter-borne flight test. This radar system consists of 4 LRUs(Line-Replacement Unit), which include antenna unit, transmitter and receiver unit, radar signal & data processing unit and display Unit. The developed core technologies include the planar array antenna, TWTA transmitter, coherent I/Q detector, digital pulse compression, MTI, DSP based Doppler FFT filter, adaptive CFAR, moving clutter compensation, platform motion stabilizer, and tracking capability. The design performance of the developed radar system is verified through various ground fixed and moving vehicle test as well as helicopter-borne field tests including MTD(Moving Target Detector) capability for the Doppler compensation due to the moving platform motion.