Search Results (4)

In this work, we address the problem of improving the classification performance of machine learning models, especially in the presence of noisy and outlier data. To this end, we first innovatively design a generalized adaptive robust loss function called $V_{\theta }(x)$. Intuitively, $V_{\theta }(x)$ can improve the robustness of the model by selecting different robust loss functions for different learning tasks during the learning process via the adaptive parameter $\theta$. Compared with other robust loss functions, $V_{\theta }(x)$ has some desirable salient properties, such as symmetry, boundedness, robustness, nonconvexity, and adaptivity, making it suitable for a wide range of machine learning applications. Secondly, a new robust semi-supervised learning framework for pattern classification is proposed. In this learning framework, the proposed robust loss function $V_{\theta }(x)$ and capped $L_{2,p}$-norm robust distance metric are introduced to improve the robustness and generalization performance of the model, especially when the outliers are far from the normal data distributions. Simultaneously, based on this learning framework, the Welsch manifold robust twin bounded support vector machine (WMRTBSVM) and its least-squares version are developed. Finally, two effective iterative optimization algorithms are designed, their convergence is proved, and their complexity is calculated. Experimental results on several datasets with different noise settings and different evaluation criteria show that our methods have better classification performance and robustness. With the Cancer dataset, when there is no noise, the classification accuracy of our proposed methods is $94.17\%$ and $95.62\%$, respectively. When the Gaussian noise is $50\%$, the classification accuracy of our proposed methods is $91.76\%$ and $90.59\%$, respectively, demonstrating that our method has satisfactory classification performance and robustness. Full article

A twin bounded support vector machine (TBSVM) is a phenomenon of symmetry that improves the performance of the traditional support vector machine classification algorithm. In this paper, we propose an improved model based on a TBSVM, called a Welsch loss with capped $L_{2,p}$-norm distance metric robust twin bounded support vector machine (WCTBSVM). On the one hand, by introducing the capped $L_{2,p}$-norm metric in the TBSVM, the problem of the non-sparse output of the regularization term is solved; thus, the generalization and robustness of the TBSVM is improved and the principle of minimizing the structural risk is realized. On the other hand, a bounded, smooth, and non-convex Welsch loss function is introduced to reduce the influence of noise, which further improves the classification performance of the TBSVM. We use a half-quadratic programming algorithm to solve the model non-convexity problem caused by Welsch loss. Therefore, the WCTBSVM is more robust and effective in dealing with noise compared to the TBSVM. In addition, to reduce the time complexity and speed up the convergence of the algorithm, we constructed a least squares version of the WCTBSVM, named the fast WCTBSVM (FWCTBSVM). Experimental results on both UCI and artificial datasets show that our model can show better classification performance on classification problems. Full article

To improve the identification accuracy of gas pipeline leakage and reduce the false alarm rate, a pipeline leakage detection method based on improved uniform-phase local characteristic-scale decomposition (IUPLCD) and grid search algorithm-optimized twin-bounded support vector machine (GS-TBSVM) was proposed. First, the signal was decomposed into several intrinsic scale components (ISC) by the UPLCD algorithm. Then, the signal reconstruction process of UPLCD was optimized and improved according to the energy and standard deviation of the amplitude of each ISC, the ISC components dominated by the signal were selected for signal reconstruction, and the denoised signal was obtained. Finally, the TBSVM was optimized using a grid search algorithm, and a GS-TBSVM model for pipeline leakage identification was constructed. The input of the GS-TBSVM model was the data processed by the IUPLCD algorithm, and the output was the real-time working conditions of the gas pipeline. The experimental results show that IUPLCD can effectively filter the noise in the signal and GS-TBSVM can accurately judge the working conditions of the gas pipeline, with a maximum identification accuracy of 98.4%. Full article

The twin parametric-margin support vector machine (TPMSVM) is an excellent kernel-based nonparallel classifier. However, TPMSVM was originally designed for binary classification, which is unsuitable for real-world multiclass applications. Therefore, this paper extends TPMSVM for multiclass classification and proposes a novel K multiclass nonparallel parametric-margin support vector machine (MNP-KSVC). Specifically, our MNP-KSVC enjoys the following characteristics. (1) Under the “one-versus-one-versus-rest” multiclass framework, MNP-KSVC encodes the complicated multiclass learning task into a series of subproblems with the ternary output $\{-1,0,+1\}$. In contrast to the “one-versus-one” or “one-versus-rest” strategy, each subproblem not only focuses on separating the two selected class instances but also considers the side information of the remaining class instances. (2) MNP-KSVC aims to find a pair of nonparallel parametric-margin hyperplanes for each subproblem. As a result, these hyperplanes are closer to their corresponding class and at least one distance away from the other class. At the same time, they attempt to bound the remaining class instances into an insensitive region. (3) MNP-KSVC utilizes a hybrid classification and regression loss joined with the regularization to formulate its optimization model. Then, the optimal solutions are derived from the corresponding dual problems. Finally, we conduct numerical experiments to compare the proposed method with four state-of-the-art multiclass models: Multi-SVM, MBSVM, MTPMSVM, and Twin-KSVC. Experimental results demonstrate the feasibility and effectiveness of MNP-KSVC in terms of multiclass accuracy and learning time. Full article