scholarly journals Classification of Benign and Malignant Lung Nodules Based on Deep Convolutional Network Feature Extraction

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Enhui Lv ◽  
Wenfeng Liu ◽  
Pengbo Wen ◽  
Xingxing Kang
Keyword(s):  
Gradient Descent ◽  
Rapid Development ◽  
Descent Method ◽  
Stochastic Gradient Descent ◽  
Lung Nodules ◽  
Gradient Descent Method ◽  
Training Methods ◽  
Convolutional Network ◽  
Deep Convolutional Network

With the rapid development of detection technology, CT imaging technology has been widely used in the early clinical diagnosis of lung nodules. However, accurate assessment of the nature of the nodule remains a challenging task due to the subjective nature of the radiologist. With the increasing amount of publicly available lung image data, it has become possible to use convolutional neural networks for benign and malignant classification of lung nodules. However, as the network depth increases, network training methods based on gradient descent usually lead to gradient dispersion. Therefore, we propose a novel deep convolutional network approach to classify the benignity and malignancy of lung nodules. Firstly, we segmented, extracted, and performed zero-phase component analysis whitening on images of lung nodules. Then, a multilayer perceptron was introduced into the structure to construct a deep convolutional network. Finally, the minibatch stochastic gradient descent method with a momentum coefficient is used to fine-tune the deep convolutional network to avoid the gradient dispersion. The 750 lung nodules in the lung image database are used for experimental verification. Classification accuracy of the proposed method can reach 96.0%. The experimental results show that the proposed method can provide an objective and efficient aid to solve the problem of classifying benign and malignant lung nodules in medical images.

scholarly journals Hyperparameter-free optimizer of stochastic gradient descent that incorporates unit correction and moment estimation

2018 ◽  
Author(s):  
Kazunori D Yamada
Keyword(s):  
Deep Learning ◽  
Gradient Descent ◽  
Mathematical Optimization ◽  
Descent Method ◽  
Learning Rate ◽  
Stochastic Gradient ◽  
Stochastic Gradient Descent ◽  
Gradient Descent Method ◽  
Moment Estimation ◽  
Estimation System

ABSTRACTIn the deep learning era, stochastic gradient descent is the most common method used for optimizing neural network parameters. Among the various mathematical optimization methods, the gradient descent method is the most naive. Adjustment of learning rate is necessary for quick convergence, which is normally done manually with gradient descent. Many optimizers have been developed to control the learning rate and increase convergence speed. Generally, these optimizers adjust the learning rate automatically in response to learning status. These optimizers were gradually improved by incorporating the effective aspects of earlier methods. In this study, we developed a new optimizer: YamAdam. Our optimizer is based on Adam, which utilizes the first and second moments of previous gradients. In addition to the moment estimation system, we incorporated an advantageous part of AdaDelta, namely a unit correction system, into YamAdam. According to benchmark tests on some common datasets, our optimizer showed similar or faster convergent performance compared to the existing methods. YamAdam is an option as an alternative optimizer for deep learning.

scholarly journals SSGD: A Safe and Efficient Method of Gradient Descent

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Jinhuan Duan ◽  
Xianxian Li ◽  
Shiqi Gao ◽  
Zili Zhong ◽  
Jinyan Wang
Keyword(s):  
Gradient Descent ◽  
Large Scale ◽  
Optimization Problems ◽  
Unit Vector ◽  
Descent Method ◽  
Stochastic Gradient ◽  
Learning System ◽  
Training Data ◽  
Stochastic Gradient Descent ◽  
Gradient Descent Method

With the vigorous development of artificial intelligence technology, various engineering technology applications have been implemented one after another. The gradient descent method plays an important role in solving various optimization problems, due to its simple structure, good stability, and easy implementation. However, in multinode machine learning system, the gradients usually need to be shared, which will cause privacy leakage, because attackers can infer training data with the gradient information. In this paper, to prevent gradient leakage while keeping the accuracy of the model, we propose the super stochastic gradient descent approach to update parameters by concealing the modulus length of gradient vectors and converting it or them into a unit vector. Furthermore, we analyze the security of super stochastic gradient descent approach and demonstrate that our algorithm can defend against the attacks on the gradient. Experiment results show that our approach is obviously superior to prevalent gradient descent approaches in terms of accuracy, robustness, and adaptability to large-scale batches. Interestingly, our algorithm can also resist model poisoning attacks to a certain extent.

scholarly journals Implicit Stochastic Gradient Descent Method for Cross-Domain Recommendation System

Sensors ◽  
2020 ◽  
Vol 20 (9) ◽  
pp. 2510
Author(s):  
Nam D. Vo ◽  
Minsung Hong ◽  
Jason J. Jung
Keyword(s):  
Gradient Descent ◽  
Recommendation System ◽  
Computation Time ◽  
Descent Method ◽  
Stochastic Gradient ◽  
Stochastic Gradient Descent ◽  
Gradient Descent Method ◽  
Target Domain ◽  
Cross Domain ◽  
Gradient Descent Algorithm

The previous recommendation system applied the matrix factorization collaborative filtering (MFCF) technique to only single domains. Due to data sparsity, this approach has a limitation in overcoming the cold-start problem. Thus, in this study, we focus on discovering latent features from domains to understand the relationships between domains (called domain coherence). This approach uses potential knowledge of the source domain to improve the quality of the target domain recommendation. In this paper, we consider applying MFCF to multiple domains. Mainly, by adopting the implicit stochastic gradient descent algorithm to optimize the objective function for prediction, multiple matrices from different domains are consolidated inside the cross-domain recommendation system (CDRS). Additionally, we design a conceptual framework for CDRS, which applies to different industrial scenarios for recommenders across domains. Moreover, an experiment is devised to validate the proposed method. By using a real-world dataset gathered from Amazon Food and MovieLens, experimental results show that the proposed method improves 15.2% and 19.7% in terms of computation time and MSE over other methods on a utility matrix. Notably, a much lower convergence value of the loss function has been obtained from the experiment. Furthermore, a critical analysis of the obtained results shows that there is a dynamic balance between prediction accuracy and computational complexity.

Globally convergent stochastic optimization with optimal asymptotic distribution

1998 ◽  
Vol 35 (02) ◽  
pp. 395-406 ◽  
Author(s):  
Jürgen Dippon
Keyword(s):  
Neural Networks ◽  
Stochastic Optimization ◽  
Asymptotic Distribution ◽  
Gradient Descent ◽  
Likelihood Estimation ◽  
Descent Method ◽  
Stochastic Gradient Descent ◽  
Gradient Descent Method ◽  
Optimal Convergence Rate ◽  
Globally Convergent

A stochastic gradient descent method is combined with a consistent auxiliary estimate to achieve global convergence of the recursion. Using step lengths converging to zero slower than 1/n and averaging the trajectories, yields the optimal convergence rate of 1/√n and the optimal variance of the asymptotic distribution. Possible applications can be found in maximum likelihood estimation, regression analysis, training of artificial neural networks, and stochastic optimization.

Wireless Brain Wave Classification for Alzheimer’s Patients via Efficient Neural Network Computation

2018 ◽  
Vol 10 (03) ◽  
pp. 1850004
Author(s):  
Grant Sheen
Keyword(s):  
Neural Network ◽  
Gradient Descent ◽  
Descent Method ◽  
Stochastic Gradient Descent ◽  
Normal Person ◽  
Gradient Descent Method ◽  
Step Size ◽  
Brain Wave ◽  
Proposed Model ◽  
Wireless Recording

Wireless recording and real time classification of brain waves are essential steps towards future wearable devices to assist Alzheimer’s patients in conveying their thoughts. This work is concerned with efficient computation of a dimension-reduced neural network (NN) model on Alzheimer’s patient data recorded by a wireless headset. Due to much fewer sensors in wireless recording than the number of electrodes in a traditional wired cap and shorter attention span of an Alzheimer’s patient than a normal person, the data is much more restrictive than is typical in neural robotics and mind-controlled games. To overcome this challenge, an alternating minimization (AM) method is developed for network training. AM minimizes a nonsmooth and nonconvex objective function one variable at a time while fixing the rest. The sub-problem for each variable is piecewise convex with a finite number of minima. The overall iterative AM method is descending and free of step size (learning parameter) in the standard gradient descent method. The proposed model, trained by the AM method, significantly outperforms the standard NN model trained by the stochastic gradient descent method in classifying four daily thoughts, reaching accuracies around 90% for Alzheimer’s patient. Curved decision boundaries of the proposed model with multiple hidden neurons are found analytically to establish the nonlinear nature of the classification.

Globally convergent stochastic optimization with optimal asymptotic distribution

1998 ◽  
Vol 35 (2) ◽  
pp. 395-406 ◽  
Author(s):  
Jürgen Dippon
Keyword(s):  
Neural Networks ◽  
Stochastic Optimization ◽  
Asymptotic Distribution ◽  
Gradient Descent ◽  
Likelihood Estimation ◽  
Descent Method ◽  
Stochastic Gradient Descent ◽  
Gradient Descent Method ◽  
Optimal Convergence Rate ◽  
Globally Convergent

A stochastic gradient descent method is combined with a consistent auxiliary estimate to achieve global convergence of the recursion. Using step lengths converging to zero slower than 1/n and averaging the trajectories, yields the optimal convergence rate of 1/√n and the optimal variance of the asymptotic distribution. Possible applications can be found in maximum likelihood estimation, regression analysis, training of artificial neural networks, and stochastic optimization.

Sign in / Sign up

Export Citation Format

Share Document