• Journal of Korean Neurosurgical Society
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• 제48권3호
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• pp.207-212
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• 2010

Objective : To assess the feasibility, safety, and effectiveness of the balloon-assisted technique with HyperForm balloon in the endovascular treatment of wide-necked intracranial aneurysms. Methods : A total of 34 patients with 34 wide-necked intracranial aneurysms were treated with endovascular coil embolization using balloon-assisted technique with Hyperform balloon. Twenty-nine aneurysms (85.3%) were located in the anterior circulation. The group of patients was comprised of 16 men and 18 women, aged 33 to 72 years (mean : 60.6 years). The size of aneurysms was in the range of 2.0 to 22.0 mm (mean 5.5 mm) and one of neck was 2.0 to 11.9 mm (mean 3.8 mm). The dome to neck ratio was ranged from 0.83 to 1.43 (1.15). Sixteen patients were treated for unruptured aneurysms and the remaining 18 presented with a subarachnoid hemorrhage. Results : In the 34 aneurysms treated by the remodeling technique with HyperForm balloon, immediate angiographic results consisted of total occlusion in 31 cases (91.2%) and partial occlusion in three cases (8.8%). There were five procedure-related complications (14.7%), including two coil protrusions and three thromboembolisms; Except one patient, all were successfully resolved without permanent neurologic deficit. No new bleeding occurred during the follow-up. Twenty patients (59%) underwent angiographic follow-up from 2 to 33 months (mean 9.2 months) after treatment. Focal recanalization with coil compaction of the neck portion was observed in 5 cases (25%). Only one case showed major recanalization and underwent stent-assisted coil embolization. Conclusion : The balloon-assisted technique with Hyperform balloon is a feasible, safe, and effective endovascular treatment of wide-necked cerebral aneurysms.

• 한국터널지하공간학회 논문집
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• 제23권4호
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• pp.253-263
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• 2021

콘크리트 구조물은 노후화와 외부 환경에 의한 요인으로 훼손된다. 이 같은 훼손은 가장 먼저 균열로 나타나고 향후에는 박락으로도 진행된다. 이러한 콘크리트 손상은 구조물이 갖는 본래의 설계 지지력을 감소시키는 주된 원인으로 작용할 수 있어 구조물의 안정성에 부정적인 영향을 미친다. 이러한 종류의 손상이 지속되면 안전사고로도 이어질 가능성이 있어 적절한 보수와 보강이 필요하다. 이를 위해서는 구조물에 대한 정확하고 객관적인 상태 점검이 이루어져야 하며 손상 영역을 탐지할 수 있는 센서 기술 또한 필요하다. 따라서 본 논문에서는 박락을 탐지할 수 있는 딥러닝 기반의 영상처리 알고리즘을 제안했다. 연구 과정에서 298장의 박락 영상을 확보하였으며, 이 가운데 253장을 학습용으로 사용했고, 나머지 45장을 테스트용으로 사용하였다. 아울러 본 논문에서는 탐지 성능을 향상하기 위해 향상된 손실함수와 데이트 증강 기법을 적용하였다. 그 결과 콘크리트 박락의 탐지 성능이 80.19%의 평균 중첩 정확도로 나타났다. 본 논문에서는 딥러닝 기반의 영상 처리 기법을 통해 콘크리트 박락을 탐지하는 기술을 개발했고, 향상된 손실 함수와 데이터 증강 기법으로 성능을 향상시키는 방법을 제안했다. 이 같은 기술은 향후 구조물의 정확한 점검과 진단에 활용될 것으로 기대된다.

• 노동경제논집
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• 제26권3호
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• pp.181-207
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• 2003

본 연구는 노동시장 이행을 중점적으로 분석할 수 있는 한국노동패널(KLIPS) 자료를 이용하여 출산 후 노동시장으로의 복귀를 결정하는 요인을 콕스 비례재해를 모형(Cox Regression Hazard Model)으로 분석한 연구이다. 분석 결과 출산 후 노동시장으로의 복귀를 결정하는 데 있어 학력이라는 인적자본이 정(+)의 효과가 뚜렷이 나타났으며, 자녀보육 대행자가 있는가의 여부에 따라 출산 후 노동시장으로 복귀할 이행률이 2배 이상 차이가 나는 것으로 밝혀졌다. 또한 출산 전 취업 형태가 임금근로일 경우 노동시장 복귀로의 이행률이 비임금근로자보다 낮은 것으로 나타났다.

• 소성∙가공
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• 제15권1호
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• pp.3-8
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• 2006

The demand fer small and high-capacity optical data storage devices has rapidly increased. The areal density of optical disk is increased by using higher numerical aperture objective lens and shorter wavelength source. A wafer-scale stacked micro objective lens with a numerical aperture of 0.85 and a focal length of 0.467mm for the 405nm blue- violet laser was designed and fabricated. A diffractive optical element (DOE) was used to compensate the spherical aberration of the objective lens. Among the various fabrication methods for micro DOE, the UV-replication process is more suitable fur mass-production. In this study, an 8-stepped DOE pattern as a master was fabricated by photolithography and reactive ion etching process. A flexible mold was fabricated for improving the releasing properties and shape accuracy in UV-replication process. In the replication process, the effects of exposing time and applied pressure on the replication quality were analyzed. Finally, the surface profiles of master, mold and molded pattern were measured by optical scanning profiler. The geometrical deviation between the master and the molded DOE was less than $0.1{\mu}m$. The diffraction efficiency of the molded DOE was measured by DOE efficiency measurement system which consists of laser source, sample holder, aperture and optical power meter, and the measured value was $84.5\%$.

• Tuberculosis and Respiratory Diseases
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• 제47권2호
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• pp.255-258
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• 1999

Pneumoconiosis, very popular to coal miners who are exposed to coal dusts dominantly, was introduced in the 19th century to describe lung diseases consequent to the inhalation of mineral dusts. Coal workers' pneumoconiosis(CWP) colloquially called "black lung" in the United States, is a distinct pathologic entity resulting from the tissue reaction to deposits of dust include the coal macule, which associated with focal emphysema constitutes the characteristic lesion of simple CWP and complicated CWP or progressive massive fibrosis(PMF). Coal mining are also associated with chronic bronchitis, chronic airflow limitation, and/or generalized emphysema. Progressive massive fibrosis lesions may imprint on and obliterate airways and vessels, and cavitation is not uncommon, being the consequence of ischemic necrosis or mycobacterial infections. We report a case which is unusual form of progressive massive fibrosis to be differentiated from lung carcinoma. It is a rapid growing PMF with ischemic necrosis. By the studies which are about risk of having progressive massive fibroois, it is predicted to be 1.4%. And the other study shows that simple pneumoconiosis clearly predisposed to PMF, with five year attack rates of 13.9%, 12.5%, 4.4% and 0.2% among men with categories 3, 2, 1, and 0 respectively at the start of the risk periods.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 금형가공,미세가공,플라스틱가공 공동 심포지엄
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• pp.35-40
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• 2005

The demand for small and high-capacity optical data storage devices has rapidly increased. The areal density of optical disk is increased using higher numerical aperture objective lens and shorter wavelength source. A wafer-scale stacked micro objective lens with a numerical aperture of 0.85 and a focal length of 0.467mm for the 405nm blue- violet laser was designed and fabricated. A diffractive optical element (DOE) was used to compensate the spherical aberration of the objective lens. Among the various fabrication methods for micro DOE, the UV-replication process is more suitable for mass-production. In this study, an 8-stepped DOE pattern as a master was fabricated by photolithography and reactive ion etching process. A flexible mold was fabricated for improving the releasing properties and shape accuracy in UV-molding process. In the replication process, the effects of exposing time and applied pressure on the replication quality were analyzed. Finally, the shapes of master, mold and molded pattern were measured by optical scanning profiler. The deviation between the master and the molded DOE was less than 0.1um. The efficiency of the molded DOE was measured by DOE efficiency measurement system which consists of laser source, sample holder, aperture and optical power meter, and the measured value was $84.5\%$.

• 대한수의학회지
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• 제47권3호
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• pp.349-356
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• 2007

Isolated splenic torsion is a rare disease, which is usually produced in deep-chest large breed dogs. A five-year old Pitbull terrier and a four-year old Yorkshire terrier were diagnosed as isolated splenic torsion with chronic form. Leukocytosis, anemia and elevated hepatic enzyme level were found in blood test and a large amount of ascites was observed. Abdominal radiography revealed splenomegaly and ascites and ultrasonography showed diffuse hypoechoic change of spleen in case 1 and hyperechoic change of spleen with focal hypoechoic regions in case 2, thromboembolism of splenic vein and abnormal direction of spleen. To identify the underlying disease of isolated splenic torsion, the histopathologic examination of excised spleen is essential and splenic neoplasia was found in case 2. Chronic isolated splenic torsion shows nonspecific clinical signs and laboratory results. Through diagnostic procedure, particularly ultrasonography, prompt diagnosis may be achieved and improve the prognosis of the patient.

• Journal of Korean Neurosurgical Society
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• 제43권6호
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• pp.304-306
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• 2008

Langerhans' cell histiocytosis (LCH) is a rare immunologic disorder characterized by histiocyte proliferation in multiple organ systems. Eosinophilic granuloma, a benign bone lesion, represents a focal form of LCH. We experienced a case of Langerhans' cell histiocytosis in a patient who presented with intracranial epidural hematoma and cyst on the midline of the frontal skull. A 10-year-old boy presented with a rapidly growing large scalp mass on the midline frontal area after mild head trauma. The scalp mass was painless and immobile. Plain skull x-ray showed a punched-out bone lesion. Computed tomography and magnetic resonance imaging showed a non-enhancing osteolytic lesion presenting with an epidural hematoma and cyst on the midline of the frontal skull. The lesion of the skull was completely resected and the patient's recovery was uneventful. The acute presentation of a solitary eosinophilic granuloma of skull with an epidural hematoma has been described in only five cases in the literature and we report the first case of LCH presenting as an intracranial epidural hematoma on frontal area.

• 제어로봇시스템학회논문지
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• 제5권5호
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• pp.558-567
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• 1999

X-ray laminography and DT(digital tomosynthesis) that can form a cross-sectional image of 3-D objects promis to be good solutions for inspecting interior defects of industrial products. DT is a kind of laminography technique and the difference is in the fact that it synthesizes the several projected images by use of the digitized memory and computation. The quality of images acquired from the DT system varies according to image synthesizing methods, the number of images used in image synthesizing, and X-ray projection angles. In this paper, a new image synthesizing method named 'log-root method' is proposed to get clear and accurate cross-sectional images, which can reduce both artifact and blurring generated by materials out of focal plane. To evaluate the quality of cross-sectional images, two evaluating criteria : (1) shape accuracy and (2) clearness of the cross-sectional images are defined. Based on these criteria, a series of simulations are performed, and the results show the superiority of the new synthesizing method over the existing ones such as averaging and minimum methods.

• Molecules and Cells
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• 제41권10호
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• pp.881-888
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• 2018

During the cortical development, cells in the brain acquire somatic mutations that can be implicated in various neurodevelopmental disorders. There is increasing evidence that brain somatic mutations lead to sporadic form of epileptic disorders with previously unknown etiology. In particular, malformation of cortical developments (MCD), ganglioglioma (GG) associated with intractable epilepsy and non-lesional focal epilepsy (NLFE) are known to be attributable to brain somatic mutations in mTOR pathway genes and others. In order to identify such somatic mutations presenting as low-level in epileptic brain tissues, the mutated cells should be enriched and sequenced with high-depth coverage. Nevertheless, there are a lot of technical limitations to accurately detect low-level of somatic mutations. Also, it is important to validate whether identified somatic mutations are truly causative for epileptic seizures or not. Furthermore, it will be necessary to understand the molecular mechanism of how brain somatic mutations disturb neuronal circuitry since epilepsy is a typical example of neural network disorder. In this review, we overview current genetic techniques and experimental tools in neuroscience that can address the existence and significance of brain somatic mutations in epileptic disorders as well as their effect on neuronal circuitry.