• Title/Summary/Keyword: Sigmoid

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Detection of Microcalcification Using the Wavelet Based Adaptive Sigmoid Function and Neural Network

  • Kumar, Sanjeev;Chandra, Mahesh
    • Journal of Information Processing Systems
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    • v.13 no.4
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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.

A Study of Freshman Dropout Prediction Model Using Logistic Regression with Shift-Sigmoid Classification Function (시프트 시그모이드 분류함수를 가진 로지스틱 회귀를 이용한 신입생 중도탈락 예측모델 연구)

  • Kim Donghyung
    • Journal of Korea Society of Digital Industry and Information Management
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    • v.19 no.4
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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%.

Does the Oral-Anal Transit Test Correlate with Colonic Manometry Findings in Children with Refractory Constipation?

  • Dranove, Jason;Fleishman, Nathan;Reddy, Saigopala;Teich, Steven
    • Pediatric Gastroenterology, Hepatology & Nutrition
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    • v.23 no.2
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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.

New Technique of Intracorporeal Anastomosis and Transvaginal Specimen Extraction for Laparoscopic Sigmoid Colectomy

  • Wang, Zheng;Zhang, Xing-Mao;Zhou, Hai-Tao;Liang, Jian-Wei;Zhou, Zhi-Xiang
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.16
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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.

Sigmoid Curve Model for Software Test-Effort Estimation (소프트웨어 시험 노력 추정 시그모이드 모델)

  • Lee, Sang-Un
    • The KIPS Transactions:PartD
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    • v.11D no.4
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    • pp.885-892
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    • 2004
  • Weibull distribution Iincluding Rayleigh and Exponential distribution is a typical model to estimate the effort distribution which is committed to the software testing phase. This model does not represent standpoint that many efforts are committed actually at the test beginning point. Moreover, it does not properly represent the various distribution form of actual test effort. To solve these problems, this paper proposes the Sigmoid model. The sigmoid function to be applicable in neural network transformed into the function which properly represents the test effort of software in the model. The model was verified to the six test effort data which were got from actual software projects which have various distribution form and verified the suitability. The Sigmoid model nay be selected by the alternative of Weibull model to estimate software test effort because it is superior than the Weibull model.

Biaxial buckling analysis of sigmoid functionally graded material nano-scale plates using the nonlocal elaticity theory (비국소 탄성이론을 이용한 S형상 점진기능재료 나노-스케일 판의 이축 좌굴해석)

  • Lee, Won-Hong;Han, Sung-Cheon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.14 no.11
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    • pp.5930-5938
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    • 2013
  • The sigmoid functionally graded mateiral(S-FGM) theory is reformulated using the nonlocal elatictiry of Erigen. The equation of equilibrium of the nonlocal elasticity are derived. This theory has ability to capture the both small scale effects and sigmoid function in terms of the volume fraction of the constituents for material properties through the plate thickness. Navier's method has been used to solve the governing equations for all edges simply supported boundary conditions. Numerical solutions of biaxial buckling of nano-scale plates are presented using this theory to illustrate the effects of nonlocal theory and power law index of sigmoid function on buckling load. The relations between nonlocal and local theories are discussed by numerical results. Further, effects of (i) power law index, (ii) length, (iii) nonlocal parameter, (iv) aspect ratio and (v) mode number on nondimensional biaxial buckling load are studied. To validate the present solutions, the reference solutions are discussed.

MLP accelerator implementation by approximation of activation function (활성화 함수의 근사화를 통한 MLP 가속기 구현)

  • Lee, Sangil;Choi, Sejin;Lee, Kwangyeob
    • Journal of IKEEE
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    • v.22 no.1
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    • pp.197-200
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    • 2018
  • In this paper, sigmoid function, which is difficult to implement at hardware level and has a slow speed, is approximated by using PLAN. We use this as an activation function of MLP structure to reduce resource consumption and speed up. In this paper, we show that the proposed method maintains 95% accuracy in $5{\times}5$ size recognition and 1.83 times faster than GPGPU. We have found that even with similar resources as MLPA accelerators, we use more neurons and converge at higher accuracy and higher speed.

Fatal Septic Internal Jugular Vein-Sigmoid Sinus Thrombosis Associated with a Malpositioned Central Venous Catheter

  • Seung, Won-Bae;Kim, Dae-Yong;Kim, Jin-Wook;Park, Yong-Seok
    • Journal of Korean Neurosurgical Society
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    • v.53 no.3
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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.

Infantile Dural Arteriovenous Fistula of the Transverse Sinus Presenting with Ocular Symptoms, Case Reports and Review of Literature

  • Sultan, Ahmed Elsayed;Hassan, Tamer
    • Journal of Korean Neurosurgical Society
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    • v.59 no.3
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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.

Precise Edge Detection Method Using Sigmoid Function in Blurry and Noisy Image for TFT-LCD 2D Critical Dimension Measurement

  • Lee, Seung Woo;Lee, Sin Yong;Pahk, Heui Jae
    • Current Optics and Photonics
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    • v.2 no.1
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    • pp.69-78
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    • 2018
  • This paper presents a precise edge detection algorithm for the critical dimension (CD) measurement of a Thin-Film Transistor Liquid-Crystal Display (TFT-LCD) pattern. The sigmoid surface function is proposed to model the blurred step edge. This model can simultaneously find the position and geometry of the edge precisely. The nonlinear least squares fitting method (Levenberg-Marquardt method) is used to model the image intensity distribution into the proposed sigmoid blurred edge model. The suggested algorithm is verified by comparing the CD measurement repeatability from high-magnified blurry and noisy TFT-LCD images with those from the previous Laplacian of Gaussian (LoG) based sub-pixel edge detection algorithm and error function fitting method. The proposed fitting-based edge detection algorithm produces more precise results than the previous method. The suggested algorithm can be applied to in-line precision CD measurement for high-resolution display devices.