• Investigative Magnetic Resonance Imaging
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• v.12 no.2
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• pp.188-196
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• 2008

Purpose : To describe the clinical, MR imaging, and pathologic findings of pediatric meningiomas. Materials and Methods : The authors retrospectively reviewed the medical records and MR images of 16 pediatric patients with pathologically proven meningioma. Mean patient age at diagnosis was 14 years (range, 3-18). MR images were reviewed for details of lesion sizes, locations, signal intensity (SI), marginal characteristics, internal architectures, enhancements, and dural and parenchymal changes. The findings of other imaging modalities and of pathological examinations were also analyzed. Results : Mean tumor size was 5.24 cm (range, 1.3-18.1 cm) and locations were supratentorial in 12 and infratentorial in 4. SI of masses were variable, that is, high in 9, iso in 4, and low in 3 on T2 weighted images (T2WI), and low (n=11), iso (n=4), or high (n=1) on T1WI images. All lesions were visualized as well-demarcated enhancing masses. Five of the tumors were heterogeneous with cystic or necrotic components. Dural attachment was observed in 11 patients and adjacent brain edema in 10. Tumors exhibited hyperdense (n=6) or isodense (n=4) on non-enhanced CT scans, and 3 of the 7 angiograms demonstrated blood supply from the internal carotid artery. Pathologic examinations revealed the following subtypes; transitional cell (n=4), meningotheliomatous (n=4), chordoid (n=2), fibrous (n=2), clear cell (n=1), hyalinized (n=1), rhabdoid papillary (n=1), and atypical (n=1). Conclusion : Pediatric meningiomas occur usually in teenagers, have diverse pathological types, and may produce atypical imaging findings, such as, a heterogeneous internal content or findings suggestive of intraaxial tumors.

• Proceedings of The Korean Society of Agricultural and Forest Meteorology Conference
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• 2001.06a
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• pp.5-7
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• 2001

수평적으로 균질한 지면 상태에서 에디 공분산 방법을 이용한 지표 플럭스 관측의 수평 규모는 측정 높이의 약 100 ∼ 200배이다(예, 최태진 등, 1999). Bottom-up 입장에서, 이 수평 규모는 지면 과정을 포함한 수치예보 모형이나 보다 큰 규모의 모형의 격자 간격보다 상당히 작다. 또한 실질적으로 자연 상태의 지면 조건은 엄밀한 의미에서 균질하지 않으며, 특히 우리나라의 경우는 지면 불균질성이 뚜렷이 나타난다.(중략)

• Proceedings of the Korea Information Processing Society Conference
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• 2004.05a
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• pp.1677-1680
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• 2004

내장형 실시간 시스템에서는 메모리관리시스템의 구현에 있어 메모리 단편화와 시간 결정성의 문제를 해결하기 위한 방법 중의 하나로 고정크기의 메모리를 할당하는 기법이 사용된다. 내장형 자바가상기계에서도 객체를 관리하는 메모리 구조인 힙에 이를 적용하여 활용할 수 있으며 구현된 예로는 simpleRTJ가 있다. 고정크기 메모리 할당 기법은 구현이 간단하기 때문에 시스템이 단순해지고 실행 시 오버헤드의 발생이 줄어드는 장점이 있다. 하지만 실제 구현에 있어서 구현의 단순화에 초점을 맞추어 프리 리스트가 구성되지 않아 메모리할당에 있어 예상할 수 없는 시간 지연이 있을 수 있으며 이는 실시간성의 보장에 치명적인 결함이 될 수 있다. 또한 배열과 문자열의 구성에 있어 실제 크기를 그대로 사용함으로써 고정크기 할당방식의 장점을 완전히 이용되지 못하고 있다. 본 논문에서는 실질적인 고정크기 할당방식의 장점을 최대한으로 이용하기 위해 객체와 메소드의 구조, 그리고 힙을 재구성하였다.

• Journal of Chest Surgery
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• v.42 no.5
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• pp.624-629
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• 2009

Background: Making the histologic diagnosis of small pulmonary nodules and ground glass opacity (GGO) lesions is difficult. CT-guided percutaneous needle biopsies often fail to provide enough specimen for making the diagnosis. Video-assisted thoracoscopic surgery (VATS) can be inefficient for treating non-palpable lesions. Preoperative localization of small intrapulmonary lesions provides a more obvious target to facilitate performing intraoperative. resection. We evaluated the efficacy of CT-guided localization with using a hook wire and this was followed by VATS for making the histologic diagnosis of small intrapulmonary nodules and GGO lesions. Material and Method: Eighteen patients (13 males) were included in this study from August 2005 to March 2008. 18 intrapulmonary lesions underwent preoperative localization by using a CT-guided a hook wire system prior to performing VATS resection for intrapulmonary lesions and GGO lesions. The clinical data such as the accuracy of localization, the rate of conversion-to-thoracotomy, the operation time, the postoperative complications and the histology of the pulmonary lesion were retrospectively collected. Result: Eighteen VATS resections were performed in 18 patients. Preoperative CT-guided localization with a hook-wire was successful in all the patients. Dislodgement of a hook wire was observed in one case. There was no conversion to thoracotomy, The median diameter of lesions was 8 mm (range: $3{\sim}15\;mm$). The median depth of the lesions from the pleural surfaces was 5.5 mm (range: $1{\sim}30\;mm$). The median interval between preoperative CT-guided with a hook-wire and VATS was 34.5 min (range: ($10{\sim}226$ min). The median operative time was 43.5.min (range: $26{\sim}83$ min). In two patients, clinically insignificant pneumothorax developed after CT-guided localization with a hook-wire and there were no other complications. Histological examinations confirmed 8 primary lung cancers, 3 cases of metastases, 3 cases of inflammation, 2 intrapulmonary lymph nodes and 2 other benign lesions. Conclusion: CT-guided localization with a hook-wire followed by VATS for treating small intrapulmonary nodules and GGO lesions provided a low conversion thoracotomy rate, a short operation time and few localization-related or postoperative complications. This procedure was efficient to confirm intrapulmonary lesions and GGO lesions.

• Journal of the Korean Arthroscopy Society
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• v.13 no.1
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• pp.14-21
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• 2009

Purpose: To investigate MRI findings of the repaired anterior cruciate ligament (ACL). Materials and Methods: Seventeen of arthroscopic ACL primary repair with sutures pull-out technique were followed for 21.4 months (range: 12 to 60 months). Stability was assessed with physical examination and KT-1000 arthrometer (MED metric, San Diego, CA) and postoperative MRI checked with time. The patients were divided into 2 groups according to the location of tear which was defined with the location of remained synovial sleeve. Group I (11 patients) comprised that the tear was located within proximal 1/3 of ACL substance and group II (6 patients) comprised below proximal 1/3. MRI findings of the repaired ACL were evaluated by its course, sharpness, thickness and signal intensity using 3 grade system and correlated with its location of tear. Results: In all cases, Lachman test and flexion-rotation drawer test were negative, pivot-shift test was less than grade 1 and the mean side-to-side difference by use of KT-1000 arthrometer was 1.4 mm (range: -1.0 to 2.5 mm). The overall continuity of the repaired ACL was well maintained in all cases. However, mild sagging was observed in 10 cases(58.8%), mild obscure contour in 6 cases (35.3%), increased thickness in 8 cases (47.1%) and slight increased signal intensity in 5 cases (29.5%). There was no statistical significance in all parameters between 2 groups. And a focal defect at the femoral attachment site in sagittal image was observed in 7 cases (41.2%) of all patients which comprised 2 cases (18.2%) of group I and 5 cases (83.3%) of group II. It was observed more frequently in group II with statistical significance (p=0.035). Conclusion: Some abnormal MRI findings such as mild sagged course, obscure contour, increased thickness and signal intensity, the focal defect at femoral attachment site could be observed even though the stability was well maintained clinically. We thought that the focal defect was affected by the location of tear of ACL.

• Journal of the Korean Geographical Society
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• v.50 no.3
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• pp.325-338
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• 2015

Telemedicine, which gives or receives medical information via ICT (information and communication technology), is regarded as innovation in a medical field and its application is various according to offline conditions. For example, the utilization of telemedicine in Korea is unfair because of the administrative discretion, which is the basic unit of telemedicine for its practical operation, in spite of the same diagnostic area. With this mind, this study investigates the cause of regional differences of telemedicine through a case of Kangwon province. Furthermore, the crucial matter is that regional differences of telemedicine are associated with digital divide; therefore, this research considers digital divide triggered by telemedicine. The core results are as follows. First, there are little measures such as increase of the staff, economic compensation for public officials, education of telemedicine facilities; accordingly, only regions, where can accept these insufficient conditions, manage the telemedicine system. Second, the interesting of a mayor or a governor and a head of a health center as a highest decision maker has something to do with different utilization of telemedicine. Third, public health doctors play a role as practical operators in telemedicine, but their stance is skeptic about telemedicine somewhat because of the relationship with the medical association opposing the implementation of telemedicine, unimproved regional health care condition, etc. Forth, it seems that the digital divide caused by the regional differences of the present telemedicine utilization does not led to tangible results and is not turned to another disparity so far, the proper measures are required considering that various health care services based on telemedicine will be extended.

• 한국HCI학회:학술대회논문집
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• 2006.02a
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• pp.865-870
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• 2006

HCI 연구의 주된 주제는 인간중심의 상호작용 환경의 개발이다. 이러한 개발과정에서 새로운 인터페이스 환경이 실생활에 어떠한 기능적 효용가치를 가져다 줄 것인가에 관한 문제가 중요하게 고려되어야 한다. 이를 위해 실질적인 적용사례 구축을 통해 효용성을 입증하는 것이 필요하다. 또한, 최근의 HCI는 기존의 인터페이스 수단을 대체하는 것을 목적으로 개발되어 왔으나, 보다 발전된 접근방법으로서 기존의 인터페이스가 소화할 수 없었던 상호작용의 의미론적 요소들을 다루는 것이 필요할 것이다. 이러한 맥락에서 기존 컴퓨팅 환경에서의 문제해결 프로세스의 한 예를 고찰하고 이것이 새로운 HCI환경에서 효과적인 방법으로 어떻게 구현될 수 있는가에 대한 구체적인 사례를 연구하였다. 본 논문은 문제해결의 한 예로서, '복수개의 결정사안 중 최선의 방안을 도출하는 의사결정과정'에서 HCI를 접목한 효과적인 의사결정 프로세스를 제안하고 이의 효용성을 검증한다. 이러한 의사결정 방법론으로 기존에 사용되는 AHP(Analytic Hierarchy Process)가 대표적이다. 일반적으로 AHP는 각 고려인자간 쌍대비교(pairwise comparisons)를 통해 중요도를 평가하는 과정을 포함한다. 이 과정을 통해 각각의 인자간의 쌍대비교치를 결정한 후 일련의 계산과정을 거쳐 그 결과를 도출한다. 이 작업은 통상적인 데스크탑 컴퓨터 환경에서 이루어진다. 본 논문에서는 각 인자간의 쌍대비교를 통한 우선순위를 결정하는 과정에서 새로운 인터페이스 환경의 적용을 위한 효과적인 연산 알고리즘을 제안하고 이의 효용성을 검증한다. 또한 의사결정 과정의 직관적 가시화를 위해 기본적인 프리미티므 도형으로 이루어진 그래픽 인터페이스를 구현하고, 기존의 의사결정 과정과 그 효용성을 비교한다.

• Investigative Magnetic Resonance Imaging
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• v.17 no.3
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• pp.224-231
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• 2013

Purpose : To evaluate the potential effects of background parenchymal enhancement of MR imaging in diagnosed breast cancer patients on the rate of additional biopsy and resultant cancer yield. Materials and Methods: 322 patients who were diagnosed with breast cancer and had undergone breast MR imaging were included in this study. Two radiologists reviewed the MRI for degree of background parenchymal enhancement and additional suspicious lesions described as BI-RADS category 4 or 5 on radiologic reports. Biopsy was done for these lesions, pathology reports were reviewed to calculate the cancer yield. Results: Background parenchymal enhancement of MR imaging in a total of 322 patients were classified as minimal degree 47.5%, mild degree 28.9%, moderate degree 12.4% and marked degree 11.2%. Among these 332 patients, MR imaging of 70 patients showed additional suspicious malignant lesions described as BI-RADS category 4 or 5, and consequently, 66 patients underwent biopsy. Biopsy rates in those with minimal or mild background parenchymal enhancement and those with moderate and marked background parenchymal enhancement were 19.9% and 22.3% (p-value 0.77) respectively. Cancer yields in those with minimal or mild background parenchymal enhancement and those with moderate and marked background parenchymal enhancement were 6.5% and 5.2% (p value 0.88) respectively. Both these results did not show stastically significant difference between the two groups. Conclusion: The degree of background parenchymal enhancement in MR imaging of breast cancer patients did not significantly impact additional biopsy rates or cancer yields.

• Communications of Mathematical Education
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• v.8
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• pp.287-301
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• 1999

방과후 수학수업이나 현행 수학능력시험 후 고3학생의 수학지도는 그 방법과 목적이 기존의 수학교과의 내용과 운영방식과는 차별화 되야 한다. 특히 교사는 이에 대한 인식과 필요한 지식이 증대 되야 하며, 교내 방과후 영재반 또는 수학관련 동아리에서 사용할 주제의 선정과 교수법이 개발되어야한다. 주제선정은 대수, 해석영역에서 연계성이 강하게 나타나는 것이 바람직하며, 수학교육의 목표에 실질적으로 부합되어야한다. 본 논문에서 우리는 일${\cdot}$이차 다항식을 예로 제시하고자 한다. 다항식은 중학교 수학교과에서 인수분해와 전개의 대상이고 고교과정에선 접선이나 정적분의 대상이다. 우리는 일${\cdot}$이차다항식을 미분, 적분, 행렬, 그리고 벡터의 입장에서 근사(approximation)의 주체로 다루었다.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.571-571
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• 2016

홍수예 경보를 통해 내수침수로 인한 인명 및 재산피해를 감소시키기 위해서는 강우­유출모형을 이용하여 정확한 내수침수 위험 구역을 예측하는 것이 중요하다. 현재 미국 환경보건국에서 개발된 SWMM 1차원 모형은 도시 유출량과 도시배수관로시스템에서의 유량 흐름을 잘 모의할 수 있지만, 실질적으로 2차원 모의의 경우 서로 다른 대상적용이나 대상범위가 다른 경우가 많아 이에 따른 모델의 추정결과가 서로 다른 경우도 발생한다. 따라서 본 연구에서는 침수로 인해 막대한 피해가 발생한 도림천 유역에서 XP-SWMM, TUFLOW 두 모형을 구축하여 유출량을 평가하고, 2차원 유출량의 특성을 비교 분석하고자 하였다. 이 연구 결과를 통하여 2차원 유출량 분석의 정확도를 높이는 기초자료로 사용될 수 있을 것이라 판단된다.