• Tuberculosis and Respiratory Diseases
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• v.53 no.1
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• pp.66-70
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• 2002

Pulmonary Sequestration is a rare congenital malformation during embryouic development which results in a cystic mass of nonfunctioning lung tissue. A diagnosis of a pulmonary sequestration has traditionally relied upon identifying the pathological arterial vessels by arteriography, computed tomography, and magnetic resonance imaging. We reported a case of pulmonary sequestration diagnosed by Doppler sonography and subsequent CT angiography. A 21-year-old-woman admitted to hospital for an investigation of recurrent pneumonia with left lower chest pain. A doppler ultrasound sonography showed an aberrant blood supply from the descending thoracic aorta to the left lower chest lesion. The pulmonary sequestration was confirmed by the subsequent CT angiograph.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2005.11a
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• pp.23-28
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• 2005

An airborne radar is an essential aviation electronic system of the helicopter to perform various missions in all-weather environments. This paper presents the results of the design and implementation of the airborne pulse doppler radar signal processor using high multi-DSP for the multi-function radar capability such as short-range, midium-range, and long-range depending on the mission of the vehicle. Particularly, the radar signal processor is developed using two DSP boards in parallel for the various radar signal processing algorithm. The key algorithms include LFM chirp waveform-based pulse compression, MTI clutter filter, MTD processor, adaptive CFAR, and clutter map. Especially airborne moving clutter Doppler spectrum compensation algorithm such as TACCAR is implemented for the multi-mode airborne radar system. The test results shows the good Doppler spectral separation for the clutter and the moving target in the flight test environment using helicopter.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.5
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• pp.734-741
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• 2003

This paper addresses the vibration mode shape Measurement technique utilizing a Continuous Scanning Laser Doppler Vibrometer (CSLDV). The continuous scanning capability is added to the conventional discrete Laser Doppler Vibrometer by reflecting the laser beams on the surface of the object using two oscillating mirrors. The bow scanning resulted from the proposed scanning method is eliminated by feedback control. The velocity output signal from the CSLDV is modulated to give the spatial velocity distribution in terms of coefficients which are obtained from the Fast Fourier Transformation of the time dependent velocity signal. Using the Chebyshev series from, the analysis of the vibration mode shape techniques for straight line scanning and 2 dimensional scanning are presented and discussed. The performance of the proposed SLDV is presented using the experimental results of the vibration mode shape of a cantilever and plate

• Journal of Sensor Science and Technology
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• v.8 no.1
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• pp.16-23
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• 1999

When a moving piezoelectric transducer detects an object in water, its receiving sensitivity is attenuated by Doppler effect. In this paper, a method for compensating the effect is suggested by using a newly designed condenser of which capacitance is varied according to the moving speed of the transducer. Using the method, the receiving resonant frequency of the transducer can be changed automatically. As a result, there is good agreement between the results of experiment and those of calculation. It is confirmed that the response sensitivity degradation of transducers due to Doppler effect can be compensated in the range of $1{\sim}10^m/_s$ moving speed.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.10
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• pp.1900-1907
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• 1992

This paper presents the vibration mode, natural frequencies and amplitudes of the circular plate due to the changes of the boundary conditions by varying free arc angles. The vibration mode, amplitudes and natural frequencies of the circular plate are obtained by time-average holographic interferometry and laser doppler vibrometer. The vibration modes of the circular plate with the mixed boundary conditions are found from the 1st mode to the 4th mode. The curve shapes of the natural frequency ratios obtained from this study are in a good agreement with other results obtained by numerical analysis. The displacement curves obtained from time average holographic interferometry and laser doppler vibrometer agree well in case of large amplitude, but show a little difference in case of small amplitude.

• Journal of Veterinary Clinics
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• v.23 no.3
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• pp.258-262
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• 2006

This study was performed to evaluate the usefulness of gray-scale and power Doppler ultrasonography, and to compare with radiography for detection of the repairing in experimentally induced bone defects in dogs. In 4 adult beagle dogs bilateral bone defects were created in 8 canine femurs as sized as 5 mm diameter. Mean detection time of the ultrasonographic endosteal callus formations(mean $14.25{\pm}2.31$ days) was significantly shorter than that of the radiographic opacity chanees(mean $23.50{\pm}2.27$ days) in the defected region. Mean time of the neovascularizd flow signal(mean $6.00{\pm}3.59$ days) from the power Doppler ultrasonographic examination was significantly shorter than that of gray-scale ultrasonographic findings. With these results, gray-scale ultransonography and power Doppler ultrasonography can be used for an early detection modality for bone healing.

• Current Industrial and Technological Trends in Aerospace
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• v.7 no.1
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• pp.113-118
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• 2009

In this paper, we described the model of noise, target for tracking radar and range tracking, angle tracking, and Doppler frequency tracking for target acquisition and tracking. Target signal as well as the noise signal is modeled as random process varying with elapsed time. This paper addresses three areas of radar target tracking: range tracking, angle tracking, and Doppler frequency tracking. In general, range tracking is prerequisite to and inherent in both angle and Doppler frequency tracking systems. First, we introduced the several range tracking and described techniques for achieving range tracking. Second, we described the radar angle tracking techniques including conical scan, sequential lobing, and monopulse. Finally, we presented concepts and techniques for Doppler frequency tracking for several radar types.

• The Journal of Korean Medicine
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• v.31 no.4
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• pp.178-186
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• 2010

Objectives: This study was to investigate the effect of moxibustion on peripheral blood flow by Doppler ultrasound in post-stroke hemiplegia patients. Methods: Moxibustion was applied on the points of LI4, TE3, TE5 and LI11 on the affected side, and blood flow of the radial artery was measured using the Minimax-Doppler-K device. Blood flow velocity and pulsation index were analyzed before, during, and after moxibustion. Results: The mean value of blood flow velocity in 13 patients showed a tendency of increase during moxibustion, but there was no significant difference in blood flow velocity before and after moxibustion, or pulsation index during and after moxibustion. In addition, among the five patients who showed marked increase tendency on the blood velocity graph, there was significant increase in blood velocity during, and after moxibustion compared with before moxibustion. Conclusions: This study suggests that moxibustion has an effect on peripheral blood flow in stroke patients with hemiplegia. Further validity tests with a larger scale sample are needed for the evidence of its practical use.

• International Journal of Aeronautical and Space Sciences
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• v.17 no.4
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• pp.614-621
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• 2016

Micro-Doppler (MD) shift caused by the micro-motion of a ballistic missile (BM) can be very useful to identify it. In this paper, the MD signatures of three scale-model BMs are investigated using a portable measurement system. The measurement system consists of an X-band 2-by-2 phase comparison mono-pulse radar, and a mechanical device that can impart controlled spinning and coning motions simultaneously to a model to yield the MD signature that replicates the characteristic of each target and the corresponding micro-motion. The coning motion determined the overall period of MD, and the spinning motion increased its amplitude. MD was also dependent on aspect angle. The designed system is portable, and can implement many micro-motions; it will contribute to analysis of MD in various situations.

• The Journal of Internal Korean Medicine
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• v.28 no.4
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• pp.709-716
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• 2007

Objective : We present reference values of flow velocities of intracranial and extracranial cerebral arteries and relation with change factor. Method : We checked transcranial Doppler ultrasonography on mean velocity, systolic velocity, pulsatility index, and resistance index of 252 patients. We also compared differences of change factor. Result : The result showed a difference by sex and age and relevance between vessels besides mean velocity of vessels related with past history and social history. Conclusion : According to the above results, females showed higher velocity of all vessels. With advancing age, subjects showed reduction in velocity and increase in pulsatility index and resistance index. Anterior cerebral, middle cerebral, and posterior cerebral artery increased in proportion to velocity of internal carotid artery and basilar artery. Vessel velocity correlated with diabetes mellitus, hypertension and hyperlipidemia.