• Journal of Korean Neurosurgical Society
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• 제30권sup1호
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• pp.68-72
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• 2001

Objective : The goal of this study was to document the influence of the treatment modality(surgery versus endovascular treatment) on the development of chronic shunt-dependent hydrocephalus in a series of 296 patients treated after aneurysmal subarachnoid hemorrhage(SAH). Methods : The following parameters were retrospectively analyzed for association with chronic shunt-dependent hydrocephalus : 1) Age and Sex, 2) Hunt and Hess grade, 3) Fisher computed tomographic grade, 4) aneurysm location, and 5) treatment modality(surgery versus endovascular treatment). Results : Thirty-six of 251 patients(14.3%) who survived the SAH and its neurological and/or medical sequelae underwent definitive shunting for treatment of chronic hydrocephalus. The rate of shunt dependency was positively correlated with a higher age, a higher Hunt and Hess grade, a higher Fisher computed tomographic grade, and aneurysms arising at the anterior communicating artery(p<0.05). Conclusion : The results of the present study indicate that the treatment modality used does not affect the risk of the later development of chronic shunt-dependent hydrocephalus(surgery, 16.2% [25 of 154] ; endovascular treatment, 11.3% [11 of 97] ; p=0.45).

• Journal of Korean Neurosurgical Society
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• 제30권7호
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• pp.842-848
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• 2001

Objectives : The mortality rate of subarachnoid hemorrhage(SAH) has been reduced recently due to refinement of microsurgical technique and improved perioperative management. Also, many survivors of SAH show excellent neurological recoveries. However, we found that a high proportion of the survivors do not fully regain their premorbid status in cognitive and memory function. Object of this study is to evaluate which factors might influence on cognitive and memory impairment in ruptured aneurysmal SAH patients. Methods : In this prospective study, a series of 66 patients with aneurysmal subarachnoid hemorrhage(SAH) from 1996 to 1998, most of whom had a "good" or "fair" neurological outcome, were assessed with various tests of cognition and memory function. All patients underwent clipping operation by pterional approach. Right side approach was performed in 16 case and left 21 cases. K-WAIS(Korean-Wechsler Adult Intelligence Scale) was used as method of cognition and memory function test. The time interval between SAH and assessment varied between 4 months and 8 months, averaging 6.2 months. Statistical analyses were carried out for each test score to see whether aneurysm site(A-com : non A-com), route of approach, age and sex, vasospasm, Hunt-Hess grade and Fisher CT group at admission, Glasgow Outcome Scale(GOS) at discharge affect cognitive and memory function. Results : Aneurysm site was not shown to be associated with performance on any test, and the initial grade (Hunt-Hess grade, Fisher CT group) of SAH and vasospasm had only minimal predictive values. The grade at discharge( GOS) was proved to be the best predictor of impairment of cognition and memory function within 1 year after operation. Conclusion : The authors conclude that the diffuse effects of SAH are more important than focal neuropathology in relation to cognitive impairment in this group of patients.

• 방송공학회논문지
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• 제24권2호
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• pp.234-242
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• 2019

본 논문에서는 일정 크기로 자른 영상의 가운데 픽셀이 SIFT 특징점인지를 판별함으로써 SIFT 특징점을 추출하는 딥 뉴럴 네트워크(Deep Neural Network)를 제안한다. 이 네트워크의 데이터 세트는 DIV2K 데이터 세트를 $33{\times}33$ 크기로 잘라서 구성하고, 흑백 영상으로 판별하는 SIFT와는 달리 RGB 영상을 사용한다. 그라운드 트루스(ground truth)는 옥타브(scale, octave)를 0, 시그마(sigma)는 1.6, 간격(intervals)은 3으로 설정하여 추출한 RobHess SIFT 특징들로 구성한다. VGG-16을 기반으로 컨볼루션 층을 13개에서 23개와 33개로 점점 깊은 네트워크를 구성하고, 영상의 스케일을 증가시키는 방법을 바꿔가며 실험을 수행한다. 출력 층의 활성화 함수로 시그모이드(sigmoid) 함수를 사용한 결과와 소프트맥스(softmax) 함수를 사용한 결과를 비교하여 분석한다. 실험결과 제안한 네트워크가 99% 이상의 추출 정확도를 가질 뿐 아니라 왜곡된 영상에 대해서도 높은 추출 반복성을 가진다는 것을 보인다.

• 대한핵의학회지
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• 제35권4호
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• pp.241-250
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• 2001

목적: 뇌동맥류파열에 의한 지주막하출혈에 동반되는 뇌혈관수축에 따른 뇌허혈 상태는 환자의 예후에 영향을 미치게 되므로 조기에 진단, 치료하는 것이 중요하다. 본 연구에서는 뇌동맥류파열에 의한 지주막하출혈 환자에서 기저/아세타졸아미드 부하 뇌혈류 SEPCT에서의 혈관예비능 유지여부가 환자의 예후를 예측하는데 도움이 되는지 알아보고자 하였다. 대상 및 방법: 대뇌동맥류 파열에 의한 지주막하출혈이 있는 환자 21명을 대상으로 하였다. CT와 뇌혈관촬영으로 혈관수축여부를 진단하였으며, 기저/아세타졸아미드 부하 Tc-99m ECD SPECT로 혈관예비능 감소 유무를 평가하였고 GOS (glasgow outcome scale)로 임상경과를 평가하였다. 혈류예비능 감소와 혈관수축의 상관 관계를 알아보고, 혈류예비능감소, 혈관수축, 기저 SPECT의 혈류결손과 Hunt-Hess 등급, CT상 지주막하 출혈량, GOS등급과의 관계를 Fishers exact test로 분석하였다. 결과: 기저 SPECT에서 혈류결손은 81% (17/21)에서 관찰되었으며, 아세타졸아미드 투여 SEPCT에서 혈관예비능 감소는 38% (8/21)에서 관찰되었고, 혈관수축도 38% (8/21)에서 관찰되었다. 혈관예비능은 임상경과(GOS로 평가)가 양호한 군에서 유지되었고(92%,12/13) 불량한 군에서 감소되어(62.5%, 5/8) (p=0.014), 환자의 임상경과를 잘 반영하였다. 또한 혈관예비능 감소군에서 지주막하출혈정도가 심하였으며(p=0.017), Hunt-Hess 등급도 불량하였다(p=0.041). 혈관예비능과 혈관수축의 상관관계를 보면 서로 일치하는 경우가 71% (15/21)였으며, 혈관수축이 없이 혈관예비능이 감소된 경우가 23% (3/13), 혈관수축을 보이면서 혈관예비능이 유지되어 있는 경우가 8예 중 3예에서 관찰되었는데 환자들의 임상결과는 혈관예비능 보존유무와 일치하였다. 결론: 혈관촬영으로 진단한 뇌혈관수축은 실제 뇌혈류못하였고 기저/아세타졸아미드 부하 뇌혈류 SPECT는 뇌의 기능과 혈류 및 뇌혈관예비능을 평가함으로써 뇌동맥류파열에 의한 지주막하출혈 환자의 예후를 예측하는데 유용한 검사라고 생각된다.

• 대한수학회보
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• 제36권4호
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• pp.671-682
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• 1999

Using a base-point free version of the infinite symmetric product we define a fibrewise infinite symmetric product for any fibration $E\;\longrightarrow\;B$. The construction works for any commutative ring R with unit and is denoted by $R_f(E)\;l\ongrightarrow\;B$. For any pointed space B let $G_I(B)\;\longrightarrow\;B$ be the i-th Ganea fibration. Defining $M_R-cat(B):= inf{i\midR_f(G_i(B))\longrihghtarrow\;B$ admits a section} we obtain an approximation to the Lusternik-Schnirelmann category of B which satisfies .g.a product formula. In particular, if B is a 1-connected rational space of finite rational type, then $M_Q$-cat(B) coincides with the well-known (purely algebraically defined) M-category of B which in fact is equal to cat (B) by a result of K.Hess. All the constructions more generally apply to the Ganea category of maps.

• 아동학회지
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• 제30권6호
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• pp.549-566
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• 2009

This study developed the Place Attachment to Childhood Home Scale and evaluated its validity and reliability. Samples consisted of 418 college students of four universities. Data were collected by questionnaire based on retrospective questions about the childhood home. Factor analysis resulted in 5 dimensions of place attachment : affection, place identity, place rootedness, playfulness, and place dependence. Especially, playfulness was a unique finding. The result of confirmatory factor analysis supported the five-factor structure. There were also significant correlations among sub-factors. The reliability of the scale appeared high (Cronbach's ${\alpha}$ = .948). Criterion-related validity was confirmed by significant correlations of the present scale with Attachment Scale to Place (Hess, 1997) and the Inventory of Parent Attachment (Armsden & Greenberg, 1987).

• Journal of Korean Neurosurgical Society
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• 제42권3호
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• pp.235-237
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• 2007

We describe a case of an unruptured basilar top aneurysm that was associated with early rupture after incomplete coiling. A 62-year-old woman with a history of several small infarctions has undergone coiling of unruptured basilar top aneurysm. Two weeks after initial coiling the patient presented with Hunt and Hess grade IV subarachnoid hemorrhage consistent with a ruptured basilar top aneurysm. Repeat angiography revealed a rupture of recanalized basilar top aneurysm. Second embolization with additional coils resulted in complete occlusion. However, her neurological status was not improved afterward and she was transferred to department of rehabilitation one month after hemorrhage with comatous state. To our knowledge, this is the first case of fatal early rupture after coiling of unruptured aneurysm. It has been speculated that coiling could cause injury to aneurysmal wall and facilitate rupture.

• Journal of Korean Neurosurgical Society
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• 제40권3호
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• pp.159-163
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• 2006

Objective : Unique Internal carotid artery angiographic findings have been found especially in very poor grade aneurysmal subarachnoid hemorrhage[SAH] patients before and during the endovascular coiling. The author investigates their patterns and classifies them into lour subtypes. Methods : Among Hunt&Hess grade IV, V SAH patients, the author could gather eight patients who showed abnormal intracranial circulation in cerebral catheter-based angiography. Results : The author introduces new term 'misery collaterals' first and has classified them into four types with the case illustrations. Type 1 is the worst condition defined as almost no intracranial circulation. Type 2 is the condition of little intracranial circulation with contrast filling just only at vessels of brain base, type 3 is of no or little cortical circulation with contrast filling at bilateral large vessels of brain base through circle of Willis channel and type 4 is of visible bilateral cortical circulation but delayed intracranial circulation time. The prognosis of these eight patients showed misery collaterals were disappointed. Conclusion : These finding can be used as the supportive information in deciding a management plan in poor grade SAH patients.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2004년도 가을 학술발표회 논문집
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• pp.110-117
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• 2004

The aim of a benchmark study is carried out nine methods are employed for ULS analysis which implicitly predict the ultimate strength of aluminium stiffened panels under axial compression. For this purpose, DNV PULS, experimental and numerical data on the ultimate strength of panels were collected. Comparison of these experimental / numerical, DNV PULS / numerical, results with theoretical solutions by the candidate methods is performed. Also it's compared that ALPS/ULSAP program is based on closed-form formula for the ULS of plates and grillages under axial compression. It is considered that ALPS/ULSAP methodology provides quite accurate and reasonable ULS calculations by a comparison with more refined FEA. Comparison of these experimental data, numerical, computational software results with the simplified solutions obtained by the candidate methods is then performed. The model uncertainties associated with the candidate methods are studied in terms of mean bias and COV (i.e., coefficient of variation) against experiments and numerical solutions, and the relative performance of the various methods is discussed.

• 천문학회보
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• 제39권2호
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• pp.85.2-85.2
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• 2014

최근 10년 동안의 측광 및 분광관측을 통하여 우리은하 내 구상성단들 중 대부분이 적어도 2개 이상의 항성종족을 갖는다고 밝혀졌다. 현재까지 이루어진 대부분의 구상성단의 항성종족 연구에서는 관측된 색등급도와 항성종족 합성모델 사이에 eye-fitting을 함으로써 항성종족 파라미터, 즉 중원소함량, 나이, 헬륨함량 등을 추정해왔다. 우리는 구상성단의 항성종족을 분석하기 위해 ${\chi}^2$-Minimization에 의거하여 구상성단과 항성종족 합성모델의 Hess Diagram을 비교하고, 수치계산 기법을 도입하여 최적의 파라미터를 추정하는 알고리즘을 개발하였다. 이 연구에서는 가상으로 만든 성단에 대하여 Recovery Test를 수행함으로써 이 알고리즘의 Self-Consistency를 검증하였고, 실제 관측결과를 사용하여 이 연구의 적용 가능성을 조사하였다.