• Journal of Information Processing Systems
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• 제13권4호
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• pp.703-715
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• 2017

Mammogram images are sensitive in nature and even a minor change in the environment affects the quality of the images. Due to the lack of expert radiologists, it is difficult to interpret the mammogram images. In this paper an algorithm is proposed for a computer-aided diagnosis system, which is based on the wavelet based adaptive sigmoid function. The cascade feed-forward back propagation technique has been used for training and testing purposes. Due to the poor contrast in digital mammogram images it is difficult to process the images directly. Thus, the images were first processed using the wavelet based adaptive sigmoid function and then the suspicious regions were selected to extract the features. A combination of texture features and gray-level co-occurrence matrix features were extracted and used for training and testing purposes. The system was trained with 150 images, while a total 100 mammogram images were used for testing. A classification accuracy of more than 95% was obtained with our proposed method.

• 디지털산업정보학회논문지
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• 제19권4호
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• pp.137-146
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• 2023

The dropout of university freshmen is a very important issue in the financial problems of universities. Moreover, the dropout rate is one of the important indicators among the external evaluation items of universities. Therefore, universities need to predict dropout students in advance and apply various dropout prevention programs targeting them. This paper proposes a method to predict such dropout students in advance. This paper is about a method for predicting dropout students. It proposes a method to select dropouts by applying logistic regression using a shift sigmoid classification function using only quantitative data from the first semester of the first year, which most universities have. It is based on logistic regression and can select the number of prediction subjects and prediction accuracy by using the shift sigmoid function as an classification function. As a result of the experiment, when the proposed algorithm was applied, the number of predicted dropout subjects varied from 100% to 20% compared to the actual number of dropout subjects, and it was found to have a prediction accuracy of 75% to 98%.

• Journal of Cerebrovascular and Endovascular Neurosurgery
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• 제26권1호
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• pp.71-78
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• 2024

Dural arteriovenous fistula (DAVF) is a rare condition affecting approximately 1.5% of 1,000,000 individuals annually. It frequently occurs in the transsigmoid and cavernous sinuses. An isolated sigmoid sinus is extremely rare and is treated by performing transfemoral transvenous embolization along the opposite transverse sinus. A 69-year-old woman presented with asymptomatic Borden type III/Cognard type III DAVF involving an isolated sigmoid sinus. She underwent a staged operation in which a navigation system was used to expose the sigmoid sinus in the operating room before transferring the patient to the angio suite for transvenous embolization. Various modalities have been used to treat DAVF, including surgical disconnection, transarterial embolization, transvenous embolization, and stereotactic radiosurgery. However, treating DAVF cases where the affected sinus is isolated can be challenging because an easily accessible surgical route may not be available. In this case, direct sinus cannulation and transvenous embolization were the most effective treatments.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제23권2호
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• pp.137-145
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• 2020

Purpose: The Oral-anal Transit Test (OTT) is a simple method of obtaining information about colonic transit. We aim to assess the correlation of OTT with the neuromuscular integrity of the colon determined by colonic manometry (CM). Methods: All patients who had OTT followed by CM were evaluated. Less than 6 of 24 markers remaining on OTT was considered normal. CM was performed per previously published guidelines. A normal CM was defined as at least one High Amplitude Propagating Contraction progressing from the most proximal sensor through the sigmoid colon. Results: A total of 34 patients underwent both OTT and CM (44% male, age 4-18 years, mean 11.5 years, 97% functional constipation +/- soiling, Hirschsprung's Disease). Of normal and abnormal OTT patients, 85.7% (6/7) and 18.5% (5/27) respectively had normal CM. When all markers progressed to at least the sigmoid colon, this was 100% predictive against colonic inertia. Greater than 50% of patients with manometric isolated sigmoid dysfunction had markers proximal to the recto-sigmoid. Conclusion: OTT and CM are both valuable studies that assess different aspects of colonic function. OTT can be used as a screening test to rule out colonic inertia. However, the most proximal extent of remaining markers does not predict the anatomical extent of the manometric abnormality, particularly in isolated sigmoid dysfunction.

• Asian Pacific Journal of Cancer Prevention
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• 제15권16호
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• pp.6733-6736
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• 2014

Background: Despite the growing acceptance of laparoscopic colon surgery, an abdominal incision is needed to remove the specimen and perform an anastomosis. Recently, natural orifice specimen extraction (NOSE) and intracorporeal anastomosis have been proposed to minimize abdominal wall trauma and improve the quality of laparoscopic colon resections Objective: To evaluate the feasibility and safety of a new approach combining intracorporeal delta-shaped anastomosis and transvaginal specimen extraction for totally laparoscopic sigmoid colectomy. Materials and Methods: Mobilization of bowel and dissection of lymph nodes were performed laparoscopically. After both proximal and distal incisal edges about 10.0 cm distance from sigmoid neoplasm were transected with an Endoscopic Linear Cutter-Straight, a small incision about 1.0 cm was created on the each colon wall of the contralateral side of the mesentery. Then anvils of an Endoscopic Linear Cutter-Straight were inserted into each colon through the small incisions, and incision and anastomosis between the walls of each colon were performed with a linear stapler. A V-shaped anastomosis was made on the wall and the remnant openings was reclosed with the Endoscopic Linear Cutter-Straight. The culdotomy was enlarged with laparoscopic ultrasound dissector. Transvaginal extraction of specimens was accomplished through a wound protector. Results: Surgery was performed for 11 patients with sigmoid cancer. No intraoperative complications or conversions occurred. The mean operating time was 132 min. All the patients were treated laparoscopically without any postoperative complications. Conclusions: The procedures of intracorporeal delta-shaped anastomosis and transvaginal specimen extraction are safe and oncologically acceptable for selected colon cancer cases.

• 정보처리학회논문지D
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• 제11D권4호
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• pp.885-892
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• 2004

소프트웨어 시험단계에 투입되는 노력의 분포를 추정하는 대표적인 모델로 Weibull 분포(Rayleigh와 지수분포 포함)가 있다. 이 모델은 시험 시작시점에서 실제로 많은 노력이 투입되는 점을 표현하지 못한다. 또한 다양한 형태를 갖고 있는 실제 시험 노력의 분포를 적절히 표현하지 못하고 있다. 이러한 문제점을 해결하기 위해 본 논문은 시그모이드 모델을 제안하였다. 신경망 분야에서 적용되고 있는 시그모이드 함수로부터 소프트웨어 시험 노력을 적절히 표현할 수 있도록 함수 형태를 변형시켰다 제안된 모델은 다양한 분포 형태를 보이고 있는 실제 수행된 소프트웨어 프로젝트로부터 얻어진 6개의 시험 노력 데이터에 적용하여 적합성을 검증하였다. 제안된 시그모이드 모델은 기존의 Weibull 모델보다 성능이 우수하여 소프트웨어 시험노력을 추정하는데 있어 와이블 모델의 대안으로 채택될 수 있을 것이다.

• 한국산학기술학회논문지
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• 제14권11호
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• pp.5930-5938
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• 2013

Erigen의 비국소 탄성이론을 이용한 S형상 점진기능재료 나노-스케일 판의 전단변형이론을 정식화하여 평형방성식을 유도하였다. 비국소 탄성이론은 미소 규모 효과를 고려할 수 있고 S형상함수는 점진기능재료의 정확한 특성 변화를 고려할 수 있다. 4변이 단순지지된 나노-스케일 판의 지배방정식을 풀기 위해 Navier 방법을 사용하였다. 거듭 제곱 지수와 비국소 변수의 효과를 나타내기 위한 나노-스케일 판의 해석적 좌굴하중을 제시하였고, 국소 탄성이론과의 관계를 수치해석 결과를 통하여 고찰하였다. 또한 (i) 거듭제곱 지수, (ii) 나노-스케일 판의 크기, (iii) 비국소 계수, (iv) 형상비 그리고 (v) 모드 수 등이 나노-스케일 판의 이축 무차원 좌굴하중에 미치는 효과에 대하여 관찰하였다. 본 연구의 결과를 검증하기 위해 참고문헌의 결과들과 비교 분석하였다.

• 전기전자학회논문지
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• 제22권1호
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• pp.197-200
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• 2018

본 논문에서는 하드웨어레벨로 구현이 어렵고 속도가 느린 sigmoid 함수를 PLAN을 이용하여 근사치로 출력하였다. 이를 MLP 구조의 활성화 함수로 사용하여 자원소모를 줄이고 속도를 개선하고자 하였다. 본 논문에서 제안하는 방법은 $5{\times}5$크기의 숫자 인식에 약 95%의 정확도를 유지하면서 GPGPU보다 약 1.83배의 빠른 속도를 보였다. 또한 MLPA가속기와 비슷한 자원을 사용함에도 더 많은 뉴런을 사용하여 높은 정확도에 빠른 속도로 수렴하는 것을 확인하였다.

• Journal of Korean Neurosurgical Society
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• 제53권3호
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• pp.183-186
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• 2013

Septic internal jugular vein-sigmoid sinus thrombosis (IJV-SST) associated with a malpositioned central venous catheter is a rare condition. It is potentially life-threatening and necessitates early diagnosis and rapid administration of appropriate medications. Unfortunately, it is difficult to diagnose due to vague clinical presentations. Several studies such as CT, MRI, and cerebral angiography should be performed and carefully examined to help make the diagnosis. We report a case of septic IJV-SST due to a malpositioned central venous catheter.

• Journal of Korean Neurosurgical Society
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• 제59권3호
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• pp.296-301
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• 2016

Dural arteriovenous fistula (DAVF) of the transverse sinus with ophthalmic manifestations in young children are rare. We reviewed two cases of direct AVF of the transverse sinus with ocular manifestations managed at our institution. The first, a 2.5 years old male child presented with left exophthalmos. Angiography revealed AVF between the occipital artery and the transverse sinus. The second, a 2 years old female child, complained of left exophthalmos. Imaging studies showed bilateral direct AVFs of the transverse sinus with bilateral dysmaturation of the sigmoid sinus. Transarterial embolization was done in both cases. Clinical and radiological follow up revealed complete cure. This report suggests that DAVF of the transverse sinus supplied by the external carotid branches can present with ophthalmic manifestations especially if there is distal venous stenosis or obliteration involving sigmoid sinus. Transarterial embolization using coils and liquid embolic agents could be safe and feasible to obliterate the fistula.