• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.485-488
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• 2013

최근 자동차 산업의 활성화로 인해 교통사고 급증이 사회 문제화 되면서 사고를 미연에 방지할 수 있는 운전자 보조 시스템 연구가 활발하게 이루어지고 있다. 일반적으로 자동차 사고 원인의 70% 이상이 운전자 과실에 의해서 발생되고 전체 추돌사고의 75%가 시속 29km 이하의 속도에서 발생한다. 이를 예방하기 위해서 운전자의 인지 판단을 보조하는 시스템의 개발이 많이 이루어지고 있는데, 예를 들어 자동 주차 시스템, AVM(Around View Monitoring) 시스템 등이 있다. 본 논문에서는 AVM 시스템 중 원근 왜곡을 보정하는 단계에서 직선 및 교점을 검출할 때, NMS(Non-Maximum Suppression)를 적용한 허프 변환 방법을 사용할 것이다. 또한 기존의 Sub-Pixel을 이용한 직선 및 교점 검출 방법과 NMS을 적용한 허프 변환 방법을 사용한 직선 및 교점을 검출하는 방법을 비교 분석함으로써 제안하는 NMS를 적용한 허프변환을 이용한 직선 및 교점을 검출하는 방법을 사용하여 보다 효율적인 AVM 시스템의 구현 가능성을 검증한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.499-503
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• 2013

자동차를 위한 전방향(omni-directional) 감시 시스템, 로봇의 시각 역할 등 다양한 비전 시스템에서 카메라가 장착되어 사용되고 있다. AVM(Around View Monitoring) 시스템에서 그리드 패턴의 코너를 검출하기 위해서는 먼저, 광각 카메라에서 획득한 비선형적인 방사 왜곡을 가진 영상의 왜곡 보정 작업을 수행하여야 한다. 이후에 왜곡이 보정된 영상 내부의 그리드 패턴 각 코너들을 자동으로 검출하기 위해서 Sub-Pixel, 허프 변환 등의 여러 가지 방법이 있으며 현재 출시된 AVM 시스템에 직선이나 교점 및 코너 검출을 위해 사용되고 있다. 본 논문에서는 왜곡 보정 영상을 입력 영상으로 받아 그리드 패턴의 코너를 자동으로 검출하는 프로그램을 설계한다. 제안하는 코너 검출 방법을 직접 구현하여 성능을 평가함으로써 AVM 시스템에서 코너를 검출하는 부분에 적용시킬 수 있음을 보인다.

• Journal of Drive and Control
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• v.17 no.4
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• pp.72-79
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• 2020

To ensure the safety of Advanced Driver Assistance Systems (ADAS) or autonomous vehicles, it is important to recognize the vehicle position, and specifically, the increased accuracy of the lateral position of the vehicle is required. In recent years, the quality of GPS signals has improved a lot and the price has decreased significantly, but extreme urban environments such as tunnels still pose a critical challenge. In this study, we proposed stable and precise lane recognition and tracking methods to solve these two issues via fusion of AVM images and vehicle sensor data using an extended Kalman filter. In addition, the vehicle's lateral position recognition and the abnormal state of RTK GPS were determined using this approach. The proposed method was validated via actual vehicle experiments in urban areas reporting multipath and signal disconnections.

• Korean Journal of Radiology
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• v.23 no.2
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• pp.202-217
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• 2022

Pulmonary arteriovenous malformation (AVM) is a congenital vascular disease in which interventional radiologists can play both diagnostic and therapeutic roles in patient management. The diagnosis of pulmonary AVM is simple and can usually be made based on CT images. Endovascular treatment, that is, selective embolization of the pulmonary artery feeding the nidus of the pulmonary AVM, and/or selectively either the nidus or draining vein, has become a first-line treatment with advances in interventional devices. However, some vascular diseases can simulate pulmonary AVMs on CT and pulmonary angiography. This subset can confuse interventional radiologists and referring physicians. Vascular mimickers of pulmonary AVM have not been widely known and described in detail in the literature, although some of these require surgical correction, while others require regular follow-up. This article reviews the clinical and radiologic features of pulmonary AVMs and their mimickers.

• Journal of Korean Neurosurgical Society
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• v.46 no.2
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• pp.116-122
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• 2009

Objective: Intracranial arteriovenous malformation (AVM) associated with aneurysm has been infrequently encountered and the treatment for this malady is challenging. We report here on our clinical experience with AVMs associated with arterial aneurysms that were managed by multimodality treatments, including clipping of the aneurysm, microsurgery, Gamma-knife radiosurgery (GKS) and Guglielmi detachable coil (GDC) embolization. Methods: We reviewed the treatment plans, radiological findings and clinical courses of 21 patients who were treated with GKS for AVM associated with aneurysm. Results: Twenty-seven aneurysms in 21 patients with AVMs were enrolled in this study. Hemorrhage was the most frequent presenting symptom (17 patients: 80.9%). Bleeding was caused by an AVM nidus in 11 cases, aneurysm rupture in 5 and an undetermined origin in 1. Five patients were treated for associated aneurysm with clipping followed by GKS for the AVM and 11 patients were treated with GDC embolization combined with GKS for an AVM. Although 11 associated aneurysms remained untreated after GKS, none of them ruptured and 4 aneurysms regressed during the follow up period. Two aneurysms increased in size despite the disappearance of the AVM nidus after GKS and then these aneurysms were treated with GDC embolization. Conclusion: If combined treatment using microsurgery, GKS and endovascular treatment can be adequately used for these patients, a better prognosis can be obtained. In particular, GKS and GDC embolization are considered to have significant roles to minimize neurologic injury.

• Archives of Craniofacial Surgery
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• v.22 no.3
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• pp.141-147
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• 2021

Background: Arteriovenous malformation (AVM) which is a high-blood-flow lesion with connections between arteries and veins without an intervening capillary bed, is difficult to manage. The ear is the second most common site of extracranial AVM. However, studies regarding the management of this condition remain lacking. The purpose of this study was to share managing experiences in our center and to investigate the treatment effect through a retrospective analysis of cases. Methods: Among 265 patients with AVM treated in our vascular anomalies center between January 2008 and January 2021, 10 patients with auricular AVM were included in the study to investigate the lesion distribution, clinical stage, and treatment methods by performing a retrospective evaluation. Results: Among 10 patients, five patients had AVMs distributed in the upper half of the ear, one patient in the lower half of the ear, and four patients in whole ear, respectively. Seven patients had Schobinger stage II, and three had stage III. One patient received surgical treatment only, four patients received sclerotherapy only, and five patients received both surgical treatment and sclerotherapy. The posttreatment status was checked as controlled in two patients, improved in seven patients, persistent in one patient. There were no worsening patients. Conclusion: Auricular AVM is a disease that is difficult to manage by one specific department, thus requiring a collaborative management effort from multidisciplinary team.

• Journal of Microbiology and Biotechnology
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• v.16 no.11
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• pp.1690-1698
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• 2006

In order to investigate the effect of dissolved oxygen (DO) level on AVM $B_{1a}$ production by a high yielding mutant of Streptomyces avermitilis, five sets of bioreactor cultures were performed under variously controlled DO levels. Using an online computer control system, the agitation speed and aeration rate were automatically controlled in an adaptive manner, responding timely to the oxygen requirement of the producer microorganism. In the two cultures of DO limitation, the onset of AVM $B_{1a}$ biosynthesis was observed to casually coincide with the fermentation time when oxygen-limited conditions were overcome by the producing microorganism. In contrast, this phenomenon did not occur in the parallel fermentations with DO levels controlled at around 30% and 40% throughout the entire fermentation period, showing an almost growth-associated mode of AVM $B_{1a}$ production: AVM $B_{1a}$ biosynthesis under the environments of high DO levels started much earlier than the corresponding oxygen-limited cultures, leading to a significant enhancement of AVM $B_{1a}$ production during the exponential stage. Consequently, approximately 6-fold and 9-fold increases in the final AVM $B_{1a}$ production were obtained in 30% and 40% DO-controlled fermentations, respectively, especially when compared with the culture of severe DO limitation (the culture with 0% DO level during the exponential phase). The production yield ($Y_{p/x}$), volumetric production rate (Qp), and specific production rate (${\bar{q}}_p$) of the 40% DO-controlled culture were observed to be 14%, 15%, and 15% higher, respectively, than those of the parallel cultures that were performed under an excessive agitation speed (350 rpm) and aeration rate (1 vvm) to maintain sufficiently high DO levels throughout the entire fermentation period. These results suggest that high shear damage of the high-yielding strain due to an excessive agitation speed is the primary reason for the reduction of the AVM $B_{1a}$ biosynthetic capability of the producer. As for the cell growth, exponential growth patterns during the initial 3 days were observed in the fermentations of sufficient DO levels, whereas almost linear patterns of cell growth were observed in the other two cultures of DO limitation during the identical period, resulting in apparently lower amounts of DCW. These results led us to conclude that maintenance of optimum DO levels, but not too high to cause potential shear damage on the producer, was crucial not only for the cell growth, but also for the enhanced production of AVM $B_{1a}$ by the filamentous mycelial cells of Streptomyces avermitilis.

• Journal of Korean Neurosurgical Society
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• v.30 no.6
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• pp.781-785
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• 2001

Cervicomedullary junction arteriovenous malformation(AVM) is extremely rare. The authors present a case of a cervicomedullary junction AVM in a 31-year-old woman presenting with recurrent intraventricular hemorrhage (IVH). Magnetic resonance imaging revealed the AVM(of a size of approximately $2{\times}2.5{\times}4cm$) extending from a lower medulla to C2-3 level. Vertebral angiography demonstrated a tightly coiled vascular mass with multiple feeders (radiculomedullary arteries) and irregular-shaped aneurysm at distal part of feeder originating at right C-1 level. The patient underwent superselective embolization of upper nidus and the aneurysm. The pertinent literature is reviewed, and diagnostic and therapeutic implications are discussed.

• Journal of Korean Neurosurgical Society
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• v.46 no.6
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• pp.577-580
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• 2009

A 47-year-old man presented with a subarachnoid hemorrhage (SAH) and right cerebellar hematoma was referred for evaluation. Cerebral angiography revealed a distal anterior inferior cerebellar artery (AICA) aneurysm associated with an arteriovenous malformation (AVM). Successful obliteration and complete removal of the aneurysm and AVM were obtained using transcortical approach under the guidance of neuronavigation system. The association of a peripheral AICA aneurysm and a cerebellar AVM by the same artery is unique. The reported cases of conventional surgery for this disease complex are not common and their results are variable. Less invasive surgery using image-guided neuronavigation system would be helpful and feasible for a peripheral aneurysm combining an AVM of the posterior fossa in selective cases

• The Korean Journal of Nuclear Medicine
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• v.34 no.5
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• pp.426-432
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• 2000

After surgical operation in patients with arteriovenous malformation (AVM), normal pressure perfusion breakthrough (NPPB) is one of the major complications. Brain perfusion SPECT with acetazolamide stress was known to be useful to evaluate the vascular reserve in several neurological and neurosurgical conditions. The authors performed acetazolamide brain perfusion SPECT in patients with AVM and compared the brain perfusion in the post-operative clinical courses. The acetazolamide brain perfusion SPECT was helpful in defining the prognosis of the patients with AVM. We describe 4 patients with AVM who had acetazolamide brain perfusion SPECT to examine the prognosis.