• 한국콘텐츠학회논문지
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• 제10권8호
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• pp.11-17
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• 2010

본 논문은 HMM기반의 상반신 제스처 인식에 대하여 연구하였다. 공간상의 제스처를 인식하기 위해서는 일단 제스처를 구성하고 있는 포즈에 대한 구분이 우선되어야 한다. 인터페이스에 사용되는 포즈를 구분하기 위해서 정면과 옆면에 설치한 적외선 카메라 두 대를 실험에 사용하였다. 그리고 각각의 적외선 카메라에서 하나의 포즈에 대한 정면 포즈와 옆면 포즈로 나눠서 획득한다. 획득한 적외선 포즈 영상은 SVM의 비선형 RBF 커널 함수를 이용하여 구분하였다. RBF 커널을 사용하면 비선형적 분류 포즈들간의 오분류 현상을 구분할 수 있다. 이렇게 구분된 포즈들의 연속은 HMM의 상태천이행렬을 이용하여 제스처로 인식된다. 인식된 제스처는 OS Value에 매핑하여 기존의 Application에 적용할 수 있다.

• 한국방재학회 논문집
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• 제4권2호
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• pp.61-69
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• 2004

가뭄은 주요 자연 재해 중의 하나이다. 가뭄 파악을 위하여 주로 강우량과 같은 기상자료를 주요 입력 자료로 활용하여 분석하고 있으나, 이러한 기상 자료는 한정된 기상 관측소로부터 얻어진 점자료에 해당된다. 따라서, 위성을 이용한 원격탐사 자료를 기상자료에서 포착할 수 없는 문제점을 보완하기 위한 자료로 활용할 수 있다는 확신 하에 본 연구를 진행하게 되었다. 본 연구에서는 NOAA 위성에 탑재되어 있는 AVHRR 센서로부터 얻어지는 자료를 이용하여 가뭄파악을 위한 분석을 실시하였다. NOAA/AVHRR로부터 얻어진 식생지수(NDVI)와 이로부터 얻을 수 있는 식생상태지수(VCI)를 이용하여 가뭄분석을 실시하였으며, 또한 광역적인 가뭄분석을 위해 위성자료를 이용하여 기후학적 물수지에 근거하는 간편한 방법을 제안하고 있다. 본 연구를 통하여 가뭄에 대한 시간적, 공간적 특성을 파악하는데 위성자료가 유용하게 이용될 수 있음을 알 수 있었으며, 습윤지표를 통하여 가뭄 지역도 작성이 가능함을 보여주고 있다.

• Journal of Korean Neurosurgical Society
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• 제29권5호
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• pp.599-603
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• 2000

Objectives : In lumbar spine surgery it is observed that the ligamentum flavum(LF) is bilayered, and the inner layers can be left in situ to prevent peridural adhesion in open lumbar disc surgeries. The purposes of this study are to investigate ultrastructural differences between the inner and outer layer of lumbar LF by electron microscopic examination, and to see whether these differences are, if present, more prominent in chronic degenerative lumbar spinal disorders as compared with acute lumbar disc diseases. Methods : Biopsy specimens of LF were obtained from nine patients undergoing lumbar spine surgery, five of them for degenerative spinal stenosis and four for acute disc herniation. During the surgery the outer layers of LF were carefully dissected from the inner layer, and four pieces($1{\times}1{\times}1-mm$) of biopsy samples were made from each layer. These were examined with electron microscope for the morphologies and the contents of the elastic and the collagen fibers. Results : The outer layer of LF showed elastic fiber degeneration as evidenced and decreased fiber content, while the inner layer was relatively preserved in both cases of degenerative spinal stenosis and acute disc herniation. The ultrastructural changes of the layers were more evident in the outer layer. Conclusion : With these observations the authors believe that the LF degeneration may occur mainly in the outer layer, and that this fact may aid in making the rationale for using the inner layer as physiologic barrier to prevent peridural adhesion in open lumbar disc surgeries.

• Journal of Korean Neurosurgical Society
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• 제58권5호
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• pp.448-453
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• 2015

Objective : Recently, the survival of patients with hepatocellular carcinoma (HCC) has been prolonged with improvements in various diagnostic tools and medical treatment modalities. Consequently, spine metastases from HCC are being diagnosed more frequently. The accurate prediction of prognosis plays a critical role in determining a patient's treatment plan, including surgery for patients with spinal metastases of HCC. We investigated the clinical features, surgical outcomes, and prognostic factors of HCC presenting with spine metastases, in patients who underwent surgery. Methods : A retrospective review was conducted on 33 HCC patients who underwent 36 operations (three patients underwent surgical treatment twice) from February 2006 to December 2013. The median age of the patients was 56 years old (range, 28 to 71; male : female=30 : 3). Results : Overall survival was not correlated with age, sex, level of metastases, preoperative Child-Pugh classification, preoperative ambulatory function, preoperative radiotherapy, type of operation, administration of Sorafenib, or the Tokuhashi scoring system. Only the Tomita scoring system was shown to be an independent prognostic factor for overall survival. Comparing the Child-Pugh classification and ambulatory ability, there were no statistically differences between patients pre- and post-operatively. Conclusion : The Tomita scoring system represents a practicable and highly predictive prognostic tool. Even though surgical intervention may not restore ambulatory function, it should be considered to prevent deterioration of the patient's overall condition. Additionally, aggressive management may be needed if there is any ambulatory ability remaining.

• Journal of Korean Neurosurgical Society
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• 제51권6호
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• pp.338-342
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• 2012

Objective : The aim of this study is to implement a critical pathway (CP) for patients undergoing lumbar laminectomy or microdiscectomy and describe the results before and after the CP in terms of length of hospital stay and cost. Methods : From March 2008 to February 2009, 61 patients underwent lumbar laminectomy or microdiscectomy due to stenosis or one- or two-level disc herniation in our department and were included in the prepathway group. After development and implementation of the CP in March 2009, 58 patients were applicable for the CP, and these were classified as the postpathway group. Results : The CP, which established a 6-day hospital stay (5 bed-days), was fulfilled by 42 patients (72.4%) in the postpathway group. The mean length of stay was 5.4 days in the postpathway group compared to 6.9 days in the prepathway group, demonstrating a 20% reduction, which was a statistically significant difference ($p{\leq}0.000$). There was a statistically significant reduction in charges for bed and nursing care (p=0.002). Conclusion : Implementation of a CP for lumbar laminectomy or microdiscectomy produced significant decreases in length of hospitalization and charges for bed and nursing care. We believe that this CP reduces the unnecessary use of hospital resources without increasing risk of adverse events.

• Journal of Korean Neurosurgical Society
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• 제42권6호
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• pp.436-440
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• 2007

Objective : Spinal cord hemangioblastoma is an uncommon vascular neoplasm with a benign nature and is associated with von Hippel-Lindau (VHL) disease in 20-30% of patients. Total removal of these tumors without significant neurological deficit remains a great challenge. The purpose of this study was to investigate the efficacy of VHL mutation analysis and to evaluate surgical outcome of patients with spinal cord hemangioblastomas. Methods : This study included nine patients treated for spinal cord hemangioblastomas at our institute between December 1994 and March 2006. There were four male and five female patients. Mean age was 37.8 years. The mean follow-up period was 22.4 months. Magnetic resonance imaging (MRI) of the complete neuraxis was done in all cases and VHL mutation analysis was performed in three cases for a definite diagnosis. Results : Six patients had intramedullary tumor, and the remaining patients had intradural extramedullary lesions. Five patients were associated with VHL disease. The von Hippel-Lindau mutation analysis was done in three patients and two of them showed VHL gene abnormality. Tumors were located in the cervical cord in five cases and in the thoracic cord in four cases. All patients underwent surgical intervention, and total removal was achieved in six cases. All patients showed improvement or, at least, clinically stationary state. Surgical complications did not develop in any cases. Conclusion : Spinal hemangioblastoma in this series has been safely and effectively removed via a posterior approach. Postoperatively, clinical outcome was excellent in the majority of cases. The VHL mutation analysis was useful in patients with family history and in those with multiple hemangioblastomas.

• Journal of Korean Neurosurgical Society
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• 제57권1호
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• pp.42-49
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• 2015

Objective : The cervicothoracic junction (CTJ) is a biomechanically and anatomically complex region that has traditionally posed problems for surgical access. In this retrospective study, we describe our clinical experiences of the treatment of metastatic spinal tumors at the CTJ and the results. Methods : From June 2006 to December 2011, 23 patients who underwent surgery for spinal tumors involving the CTJ were enrolled in our study. All of the patients were operated on through the posterior approach, and extent of resection was classified as radical, debulking, and simple neural decompression. Adjuvant radiation therapy (RT) was also considered. Visual analog scale score for pain assessment and Medical Research Council (MRC) grade for motor weakness were used, while pre- and post-operative performance status was evaluated using the Eastern Cooperative Oncology Group (ECOG). Results : Almost all of the patients were operated using palliative surgical methods (91.3%, 21/23). Ten complications following surgery occurred and revision was performed in four patients. Of the 23 patients of this study, 22 showed significant pain relief according to their visual analogue scale scores. Concerning the aspect of neurological and functional recovery, mean MRC grade and ECOG score was significantly improved after surgery (p<0.05). In terms of survival, radiation therapy had a significant role. Median overall survival was 124 days after surgery, and the adjuvant-RT group (median 214 days) had longer survival times than prior-RT (63 days) group. Conclusion : Although surgical procedure in CTJ may be difficult, we expect good clinical results by adopting a palliative posterior surgical method with appropriate preoperative preparation and postoperative treatment.

• Nuclear Engineering and Technology
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• 제41권8호
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• pp.1025-1044
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• 2009

Systematic research has been conducted by KAERI to develop a supercritical carbon dioxide Brayton cycle energy conversion system coupled with a sodium cooled fast reactor. For the development of the supercritical $CO_2$ Brayton cycle ECS, KAERI researched four major fields, separately. For the system development, computer codes were developed to design and analyze the supercritical $CO_2$ Brayton cycle ECS coupled with the KALIMER-600. Computer codes were developed to design and analyze the performance of the major components such as the turbomachinery and the high compactness PCHE heat exchanger. Three dimensional flow analysis was conducted to evaluate their performance. A new configuration for a PCHE heat exchanger was developed by using flow analysis, which showed a very small pressure loss compared with a previous PCHE while maintaining its heat transfer rate. Transient characteristics for the supercritical $CO_2$ Brayton cycle coupled with KALIMER-600 were also analyzed using the developed computer codes. A Na-$CO_2$ pressure boundary failure accident was analyzed with a computer code that included a developed model for the Na-$CO_2$ chemical reaction phenomena. The MMS-LMR code was developed to analyze the system transient and control logic. On the basis of the code, the system behavior was analyzed when a turbine load was changed. This paper contains the current research overview of the supercritical $CO_2$ Brayton cycle coupled to the KALIMER-600 as an alternative energy conversion system.

• 대한기계학회논문집A
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• 제37권5호
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• pp.665-671
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• 2013

제 4 세대 소듐냉각 고속로에는 중간열교환기(IHX), 붕괴열제거 열교환기(DHX), 공기 열교환기(AHX), 핀형 소듐-공기 열교환기(FHX) 및 증기발생기(SG)를 포함한 다양한 열교환기들이 설치된다. 본 연구에서는 STELLA-1 시험루프에 설치된 소듐-공기 열교환기인 AHX 와 SELFA 시험루프에 설치될 핀형(finned) 소듐-공기 열교환기인 FHX 등 2 기의 열교환기 설계에 대해 3D 상세 유한요소해석을 수행하고, 동 결과에 기초하여 고온설계 기술기준을 따라 크리프-피로 손상평가를 수행하였다. 손상 평가결과 AHX와 FHX는 의도하는 크리프 피로 손상 하중 하에서 구조 건전성을 유지하는 것으로 확인되었다.

• 대한한의학방제학회지
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• 제17권2호
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• pp.163-174
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• 2009

Reactive oxygen species(ROS) can induce hepatotoxicity and trigger apoptosis in the liver. In this study, we investigated the sulfated polysaccharide A-1 from Opuntia ficus-indica against alcoholic oxidative stress in human liver Hep G2 cell. An antioxidant substance A-1 obtained from the enzymatic extract of Opuntia ficus-indica fruit was purified by DEAE-cellulose ion exchange and sephadex G-100 gel permeation chromatography. The purification yield and molecular weight were 14.3% and 1.8 KDa, respectively. The A-1 predominately contained arabinose, galactose, rhamnose and also sulfate group. The structure of A-1 was investigated by periodate oxidation, FT-IR spectroscopy, $^1H$-NMR spectroscopy. The A-1 mainly composed of alternating unit of ${\rightarrow}4$)-$\alpha$-L- Rapp-2-$SO_3^-$-$\alpha$-L-Galp-($1{\rightarrow}$ and branched linkage of $\beta$-D-Arbp- ($5{\rightarrow}$. The antioxidative activity was measured using the SOD, CAT activity and GSH assay, respectively. The expression of Nrf2 protein was analyzed by western blotting. The viable cell count analyzed by autofluorescence. Oxidative stress induced by ethanol(1 M) were dramatically reduced by A-1 treatment. A-1 also prevented cell death induced by oxidative stress. It also increased expression Nrf2 protein level. We concluded that sulfated polysaccharide A-1 from Opuntia ficus-indica effectively protect Hep G2 liver cell from alcoholic oxidative stress.