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In real-world scenarios, new audio classes with insufficient samples usually emerge continually, which motivates the study of few-shot class-incremental audio classification (FCAC) in this paper. FCAC aims to enable the model to recognize new audio classes while remembering the base ones continually. To solve the FCAC problem, the discriminability of the prototypes is vital to the model's classification performance. Thus, we proposed a method to learn the discriminative prototypes from two aspects. First, since the generalization ability of the embedding module (EM) significantly affects the discriminability of the prototypes, the proposed method employs a scheme of pseudo-episodic incremental training to train the EM by simulating the test scenario. Second, to enable the model to achieve a balanced classification performance on both base and new audio classes, the proposed method employs a selective-attention module to adjust different prototypes to enhance their discriminability. Extensive experimental results demonstrate that the proposed method achieves state-of-the-art performance in solving the FCAC problem. Notably, the proposed method achieves a comprehensive performance score (CPS) of 87.82% and 59.25% on the Neural Synthesis musical notes of 100 classes (NSynth-100) and Free sound clips of 89 classes (FSC-89) datasets, respectively, which outperforms the comparison methods. Our code is available at https://github.com/chester-w-xie/DPL_FCAC. • The few-shot class-incremental audio classification problem is studied in this paper. • The proposed method expands the model with discriminative prototypes. • A scheme is proposed to enhance the generalization ability of the embedding module. • A selective-attention-based module is proposed for prototype adjustment. • The proposed method achieves state-of-the-art performance in solving the problem. [ABSTRACT FROM AUTHOR]

Nearest neighbor-based methods are classic techniques that, due to their efficiency, still are widely used today. However, they have not been broadly applied to solve the multi-instance multi-label (MIML) problem, a supervised learning paradigm that combines multi-instance (MI) and multi-label (ML) learning. This work presents new neighbor-based approaches for solving MIML problems. On the one hand, MIML data are transformed into ML data and ML nearest neighbor algorithms are used. On the other hand, algorithms that directly address MIML data and use a bag-based distance are proposed. A comprehensive study and an overall comparison have been conducted to study the performance of these methods using different configurations. Experiments included 16 datasets and 8 performance metrics. The results and statistical tests showed that the problem transformation applied and the distance function used impacted the performance and that the approaches that do not transform the problem obtained the best predictive results. Furthermore, most of the proposed algorithms outperformed the MIMLkNN algorithm, the state-of-art algorithm for MIML learning based on nearest-neighbor. Therefore, the relevance and capabilities of neighbor-based approaches to obtain competitive results in MIML learning are shown. Finally, all the algorithms developed in this paper have been included in the MIML library to facilitate the comparison with other future proposals. • New kNN methods for MIML based on logistic regression, gravitational model, and MAP. • Exhaustive study with 16 datasets and 8 evaluation measures to study the performance. • The transformation and the distance function influenced the predictive performance. • The gravitational model gets the best results with reasonable time complexity. • All the proposals outperform the state-of-art kNN-based algorithm in MIML. [ABSTRACT FROM AUTHOR]

Multi-agent reinforcement learning (MARL) has been successfully applied in many fields. In MARL, the policy evaluation problem is one of crucial problems. In order to solve this problem, distributed Temporal-Difference (TD) learning algorithm is one of the most popular methods in a cooperative manner. Despite its empirical success, however, the theory of the adaptive variant of distributed TD learning still remain limited. To fill this gap, we propose an adaptive distributed temporal-difference algorithm (referred to as MS - ADTD) under Markovian sampling over time-varying networks. Furthermore, we rigorously analyze the convergence of MS - ADTD , the theoretical results show that the local estimation can converge linearly to the optimal neighborhood. Meanwhile, the theoretical results are verified by simulation experiments. • This paper proposes a distributed adaptive TD learning algorithm under Markovian sampling. • It theoretically analyzes the non-asymptotic convergence performance of the proposed algorithm. • It verifies the performance of the proposed algorithm by experiments. [ABSTRACT FROM AUTHOR]

• Applying MSE to the field of lithology discrimination. • Designing a lithology recognition model based on SA optimized SVM algorithm. • Forming a set of lithology recognition methods based on machine learning. • Establishing a lithology intelligent recognition model. Lithology identification is an important part of petroleum drilling engineering. Accurate identification of lithology is the foundation to ensure the smooth operation of drilling engineering. Conventional lithology recognition mainly relies on human experience. The recognition accuracy depends on the level of technical personnel and the recognition response time is lagging. It is difficult to meet the demand. How to achieve rapid and intelligent recognition of lithology is one of the core technical problems faced by oil drilling. In order to solve this problem, this paper uses the mechanical specific energy and other ground parameters to establish a rapid and intelligent recognition method of lithology based on the simulated annealing optimization support vector machine model. In order to improve the accuracy of the model recognition, a large number of methods have been developed from two classes and multiple classes, simulation analysis results show that the lithology recognition model based on the principle of mechanical specific energy and the simulated annealing optimization support vector machine algorithm can predict a priori unknown data with a prediction accuracy of over 90%. Compared with the support vector machine model and the K-means model, simulated annealing optimization support vector machine is used for comparative analysis, the algorithm to establish a lithology recognition model has better performance and higher accuracy. The intelligent identification model of lithology based on the principle of mechanical specific energy and simulated annealing optimization support vector machine algorithm established in this paper can quickly and accurately identify lithology, and provide new technical support for oil drilling formation analysis. [ABSTRACT FROM AUTHOR]

Feature selection (FS) is recognized as one of the majority public and challenging problems in the Machine Learning domain. FS can be examined as an optimization problem that needs an effective optimizer to determine its optimal subset of more informative features. This paper proposes a wrapper FS method that combines chaotic maps (CMs) and binary Group Search Optimizer (GSO) called CGSO, which is used to solve the FS problem. In this method, five chaotic maps are incorporated with the GSO algorithm's main procedures, namely, Logistic, Piecewise, Singer, Sinusoidal, and Tent. The GSO algorithm is used as a search strategy, while k-NN is employed as an induction algorithm. The objective function is to integrate three main objectives: maximizing the classification accuracy value, minimizing the number of selected features, and minimizing the complexity of generated k-NN models. To evaluate the proposed methods' performance, twenty well-known UCI datasets are used and compared with other well-known published methods in the literature. The obtained results reveal the superiority of the proposed methods in outperforming other well-known methods, especially when using binary GSO with Tent CM. Finally, it is a beneficial method to be utilized in systems that require FS pre-processing. • A novel feature selection method is proposed for classification task. • Five Chaotic Group Search Optimizers are investigated. • Twenty UCI datasets were used in the experiments. • Our methods got a higher accuracy results using a fewer number of features. [ABSTRACT FROM AUTHOR]

Corporate financial distress prediction research has been ongoing for more than half a century, during which many models have emerged, among which ensemble learning algorithms are the most accurate. Most of the state-of-the-art methods of recent years are based on gradient boosted decision trees. However, most of them do not consider using feature importance for feature selection, and a few of them use the feature importance method with bias, which may not reflect the true importance of features. To solve this problem, a heuristic algorithm based on permutation importance (PIMP) is proposed to modify the biased feature importance measure in this paper. This method ranks and filters the features used by machine learning models, which not only improves accuracy but also makes the results more interpretable. Based on financial data from 4,167 listed companies in China between 2001 and 2019, the experiment shows that compared with using the random forest (RF) wrapper method alone, the bias in feature importance is indeed corrected by combining the PIMP method. After the redundant features are removed, the performance of most machine learning models is improved. The PIMP method is a promising addition to the existing financial distress prediction methods. Moreover, compared with traditional statistical learning models and other machine learning models, the proposed PIMP-XGBoost offers higher prediction accuracy and clearer interpretation, making it suitable for commercial use. • The model Combines a corrected feature selection measure and XGBoost. • Permutation importance can correct the bias of feature importance. • The model is validated on Chinese listed companies datasets over five metrics. • The model is proved to outperform several benchmark techniques. • The feature importance and partial dependence plot enhance model interpretation. [ABSTRACT FROM AUTHOR]

Due to the actual operation of the wind turbine, the collected fault data sets are limited, and it is difficult to realize fault diagnosis through the correlation between variables. To solve this problem, a fault diagnosis method based on virtual expansion and spherical mapping model is proposed in this paper. Firstly, Hermite interpolation is applied to discrete wind power data samples to obtain an interpolation curve about the characteristics of the sample, and a synchronous sampling method is adopted for the interpolation curve to construct a virtual sample. Then, the features of the virtual sample are mapped to a three-dimensional space. Define the spherical data model and perform spherical fitting in a three-dimensional coordinate system. Finally, feature extraction is performed on the fitted spherical surface for training and testing extreme learning machine (ELM). The distribution law of fault data in the spherical model is summarized. Using the data generated based on the Bootstrap method as a control group, comparative experiments were carried out in back-propagation neural network (BP), Probabilistic Neural Network (PNN), General Regression Neural Network (GRNN), and Support Vector Machine (SVM), which verified the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

[Display omitted] • Two novel DR methods are proposed to extract critical discriminative information. • Neighborhood size parameters of DR models are decided adaptively via data similarity. • Outside data can be projected directly through SD-IsoP that prevents over-fitting. • Margins between classes in reduced space can be maximized by proposed methods. As one of the most popular nonlinear dimensionality reduction methods, Isomap has been widely used in pattern recognition and machine learning. However, Isomap has the following problems: (1) Isomap is an unsupervised dimensionality reduction method, it cannot use class label information to obtain discriminative low dimensional embedding for classification; (2) The embedding performance of Isomap is sensitive to neighborhood size parameter; (3) Isomap cannot deal with outside new data by direct embedding. In this paper, a novel dimensionality reduction method called supervised discriminant Isomap is proposed to solve the first two problems mentioned above. Specifically, first, raw data points are partitioned into different manifolds by using their class label information. Then, supervised discriminant Isomap aims at seeking an optimal nonlinear subspace to preserve the geometrical structure of each manifold according to the Isomap criterion, and to enhance the discriminating capability by maximizing the distances between data points of different classes and the maximum margin graph regularization term. Finally, the corresponding optimization problems are solved by using eigen-decomposition algorithm. Further, we extend supervised discriminant Isomap to a linear dimensionality reduction method called supervised discriminant Isomap projection for handling the above three problems. Moreover, our approaches have three important characteristics: (1) Proposed methods adaptively estimate the local neighborhood surrounding each sample based on data density and similarity; (2) The objective functions of proposed methods can maximize margins between the each classes in the dimension-reduced feature space; (3) The objective functions of proposed methods have closed-form solutions. Furthermore, our methods can capture more discriminative information from raw data than other Isomap based methods. Extensive experiments on nine data sets demonstrate that the proposed methods are superior to the related state-of-the-art methods. [ABSTRACT FROM AUTHOR]