• Journal of Chest Surgery
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• 제49권1호
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• pp.22-28
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• 2016

Background: Carotid endarterectomy (CEA) with selective shunting is the surgical method currently used to treat patients with carotid artery disease. We evaluated the incidence of major postoperative complications in patients who underwent CEA with selective shunting under transcranial Doppler (TCD) at our institution. Methods: The records of 45 patients who underwent CEA with TCD-based selective shunting under general anesthesia from November 2009 to June 2015 were reviewed. The risk factors for postoperative complications were analyzed using univariate and multivariate analysis. Results: Preoperative atrial fibrillation was observed in three patients. Plaque ulceration was detected in 10 patients (22.2%) by preoperative computed tomography imaging. High-level stenosis was observed in 16 patients (35.5%), and 18 patients had contralateral stenosis. Twenty patients (44.4%) required shunt placement due to reduced TCD flow or a poor temporal window. The 30-day mortality rate was 2.2%. No cases of major stroke were observed in the 30 days after surgery, but four cases of minor stroke were noted. Univariate analysis showed that preoperative atrial fibrillation (odds ratio [OR], 40; p=0.018) and ex-smoker status (OR, 17.5; p=0.021) were statistically significant risk factors for a minor stroke in the 30-day postoperative period. Analogously, multivariate analysis also found that atrial fibrillation (p<0.001) and ex-smoker status (p=0.002) were significant risk factors for a minor stroke in the 30-day postoperative period. No variables were identified as risk factors for 30-day major stroke or death. No wound complications were found, although one (2.2%) of the patients suffered from a hypoglossal nerve injury. Conclusion: TCD-based CEA is a safe and reliable method to treat patients with carotid artery disease. Preoperative atrial fibrillation and ex-smoker status were found to increase the postoperative risk of a small embolism leading to a minor neurologic deficit.

• 대한방사선기술학회지:방사선기술과학
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• 제32권1호
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• pp.87-93
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• 2009

배경/목적 : 경추골동맥 기시부의 동맥경화증은 경추기저 국소빈혈증의 위험인자 중 하나이기 때문에 경추골동맥 기시부를 확인해야 할 필요가 있다. 색도플러 초음파검사에 의한 경추골동맥 기시부의 관찰 및 평가는 기술적으로 어려움이 있으며, 특히 왼쪽 기시부는 더욱 그렇다. 이 연구의 목적은 색도플러 초음파검사 시경추골동맥 기시부의 관찰률을 높이는 것이다. 대상 및 방법 : 경동맥을 포함한 경추골동맥의 색도플러 초음파검사가 198명에 대해 시행되었다. 경추골동맥 기시부를 다른 혈관의 기시부와 더 쉽게 구분하기 위해 목 윗부분의 경추동맥에서부터 쇄골하동맥 측으로 검사를 시행하였다. 검사 기술적으로 경추골동맥 기시부가 바로누운자세의 자연스러운 위치에서 관찰되지 않을 경우, 초음파 트랜스듀서를 쇄골 측으로 밀고, 그래도 관찰되지 않을 경우 다른 손으로 어깨를 밀어 관찰을 시도하였다. 경추골동맥 기시부의 깊이와 위 세 가지 방법 및 그에 따른 관찰률을 확인하기 위하여, 검사된 초음파 영상에서 관찰된 경추골동맥 기시부의 위치를 3.0 cm 이하와 그 이상으로 구분하였다. 결 과 : 오른쪽 경추골동맥 기시부는 97%, 왼쪽 경추골동맥 기시부는 92%에서 관찰되었다. 3.0 cm 이하에서 관찰된 오른쪽 경추골동맥 기시부 중 자연스러운 자세, 트랜스듀서 밀기, 그리고 어깨 밀기에서 관찰된 경우는 각각 98.6%, 1.4%, 그리고 0.0%이었다. 그리고 3.0 cm 보다 더 깊은 위치에서 관찰된 오른쪽 경추골동맥 기시부 중 자연스러운 자세, 트랜스듀서 밀기, 그리고 어깨 밀기에서 관찰된 경우는 각각 81.2%, 14.6%, 그리고 4.2%이었다. 3.0 cm 이하에서 관찰된 왼쪽쪽 경추골동맥 기시부 중 자연스러운 자세, 트랜스듀서 밀기, 그리고 어깨 밀기에서 관찰된 경우는 각각 85.4%, 10.7%, 그리고 3.9%%이었다. 그리고 3.0 cm 보다 더 깊은 위치에서 관찰된 오른쪽 경추골동맥 기시부 중 자연스러운 자세, 트랜스듀서 밀기, 그리고 어깨 밀기에서 관찰된 경우는 각각 55.7%, 30.4%, 그리고 13.9%이었다. 결 론 : 경추골동맥의 색도플러 초음파검사에서 그 기시부가 바로누운자세의 자연스러운 위치에서 관찰되지 않을 경우, 초음파 트랜스듀서를 쇄골 측으로 밀거나 그래도 관찰되지 않을 경우 다른 손으로 어깨를 밀어 관찰을 시도한다면, 관찰률을 좀더 높일 수 있을 것으로 사료된다.

• 대기
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• 제30권4호
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• pp.347-360
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• 2020

The automatic algorithm optimized for the Korean Peninsula was developed to detect and track the center of typhoon based on a geometrical method using high-resolution retrieved WISSDOM (WInd Syntheses System using DOppler Measurements) wind and reflectivity data. This algorithm analyzes the center of typhoon by detecting the geometric circular structure of the typhoon's eye in radar reflectivity and vorticity 2D field data. For optimizing the algorithm, the main factors of the algorithm were selected and the optimal thresholds were determined through sensitivity experiments for each factor. The center of typhoon was detected for 5 typhoon cases that approached or landed on Korean Peninsula. The performance was verified by comparing and analyzing from the best track of Korea Meteorological Administration (KMA). The detection rate for vorticity use was 15% higher on average than that for reflectivity use. The detection rate for vorticity use was up to 90% for DIANMU case in 2010. The difference between the detected locations and best tracks of KMA was 0.2° on average when using reflectivity and vorticity. After the optimization, the detection rate was improved overall, especially the detection rate more increased when using reflectivity than using vorticity. And the difference of location was reduced to 0.18° on average, increasing the accuracy.

• The Journal of the Acoustical Society of Korea
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• 제29권3E호
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• pp.107-110
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• 2010

In this paper, the rationale and contents of the special issue of the Journal of the Acoustical Society of Korea regarding comprehensive reviews on past, present and future of biomedical ultrasound are described. Brief descriptions of invited articles are given, and efforts by all contributing authors are gratefully acknowledged.

• 천문학논총
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• 제7권1호
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• pp.19-23
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• 1992

We investigated the "tilting" of the Universe, i.e., a non-Doppler origin of the dipole moment of the cosmic background radiation (CBR). Superhorizon-sized isocurvature, rotational and true vacuum bubble perturbations are considered. We show that the more natural way of the "tilting" the Universe is via the true vacuum bubble perturbation. Nevertheless, due to the small filling fraction of the bubbles of viable extended inflationary models, we find that the probability of the real occurrence in the Universe is quite insignificant.

• 한국임상수의학회지
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• 제19권1호
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• pp.95-99
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• 2002

A 6-month-old, intacted male dog was admitted to Seoul Animal Medical Center. The referring veterinarian suspected that the patient might have congenital cardiac problem. It was diagnosed with patent ductus arteriosus(PDA) based on the physical examination, auscultation, radiography, electrocardiography and ultrasonogrphy. After surgical ductus closure, there were improved clinical conditions through by alleviation of atrial fibrilation and left heart enlargement.

• Bulletin of the Korean Chemical Society
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• 제16권3호
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• pp.256-260
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• 1995

Laser induced fluorescence spectra of OH produced from photodissociation of $H_2O_2$ at 280-290 nm in the gas phase have been observed. By analyzing the Doppler profiles, the anisotropy parameter($\beta$ =-0.7) and the center of mass translational energy of the fragments have been measured. The measured energy distribution is well described by an impulsive model. The excited state leading to dissociation is found to be of 1Au symmetry. The dissociation from this state is prompt and direct with the fragment OH rotating in the plane perpendicular to the O-O bond axis.

• 로봇학회논문지
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• 제15권1호
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• pp.32-38
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• 2020

This paper describes a method for tracking attitude and position of underwater robots. Underwater work with underwater robots is subject to differences in work efficiency depending on the skill of the operator and the utilization of additional sensors. Therefore, this study developed an underwater robot that can operate autonomously and maintain a certain attitude when working underwater to reduce difference of work efficiency. The developed underwater robot uses 8 thrusters to control 6 degrees of freedom motion, IMU (Inertial Measurement Unit), DVL (Doppler Velocity Log) and PS (Pressure Sensor) to measure attitude and position. In addition, the thruster allocation algorithm was designed to follow the control desired value using 8 thrusters, and the motion control experiments were performed in the engineering water basin using the thruster allocation method.

• Wind and Structures
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• 제15권1호
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• pp.65-86
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• 2012

Over the last decade substantial improvements have been made in our ability to observe the tropical cyclone boundary layer. Low-level wind speed maxima have been frequently observed in Global Positioning System dropwindsonde (GPS sonde) profiles. Data from GPS sondes and coastal Doppler radars were employed to evaluate the characteristics of tropical cyclone vertical wind profiles in open ocean conditions and at landfall. Changes to the mean vertical wind profile were observed azimuthally and with decreasing radial distance toward the cyclone center. Wind profiles within the hurricane boundary layer exhibited a logarithmic increase with height up to the depth of the wind maximum.

• 한국항행학회논문지
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• 제28권2호
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• pp.250-253
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• 2024

This paper proposes a low-power waveform for a long-range air-to-air data link. In the case of an air-to-air data link, data communication is performed in the air and high Doppler shift may occur depending on the flight speed, so a waveform based on the non-coherent method is suitable. In addition, since it is mounted on an aircraft, it must have low power characteristics. This paper proposes a waveform that combines a modulation technique based on frequency modulation and pulse position modulation that can turn on/off the transmission signal. As a result of the performance analysis, it was shown that the performance was suitable for air-to-air operation while showing low power characteristics.