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• Variational Quantum Circuits (VQCs) play a key role in several applications. • VQCs are parameterized quantum circuits trained by using classical optimizers. • The paper proposes to apply memetic algorithms to train VQCs. • The designed memetic algorithm outperforms the state-of-the-art classical optimizers. Among the ready-to-implement quantum algorithms, Variational Quantum Circuits (VQCs) play a key role in several applications, including machine learning. Their strength lies in the use of a parameterized quantum circuit that is trained by means of an optimization algorithm run on a classical computer. In such a scenario, there is a strong need to design appropriate classical optimization schemes that deal efficiently with VQCs and pave the way for quantum advantage in machine learning. Among possible optimization schemes, those based on evolutionary computation are finding increasing interest, given the unconventional and nonanalytical nature of the problem to be solved. This paper proposes to apply memetic algorithms to train VQCs used as quantum classifiers and shows the benefits of exploiting this evolutionary optimization technique through a comparative experimental session. [ABSTRACT FROM AUTHOR]

The Black Hole Clustering (BHC) algorithm is a density-based partitional clustering method inspired by the Density-based Spatial Clustering of Applications with Noise (DBSCAN). It does not require the number of clusters nor the computation of the pair-wise distance matrix between the data points, making it faster than DBSCAN. Also, it only needs one parameter that is intuitively easier to set than the epsilon parameter of DBSCAN. However, BHC needs the allocation of the so-called black holes that have to be linearly independent, making the algorithm in its current version suitable only for two or three-dimensional data sets. In this paper, we propose a generalized version of the black hole clustering algorithm (GBHC) by introducing a novel black hole allocation procedure for higher-dimensional data spaces. Furthermore, the proposed method is data-independent, so we have to run it once to obtain the black hole positions for all finite-dimensional metric spaces. We performed extensive computational experiments to compare GBHC with DBSCAN. The results show that both algorithms obtain comparable clustering solutions. GBHC, however, outperforms DBSCAN in computational complexity and explainability. • We propose a novel method to place the black holes for high-dimensional data sets. • This method is called Generalized Black Hole Clustering and it is data-independent. • We run the new method once to get black hole positions in all finite metric spaces. • We compare the GBHC and DBSCAN algorithms using several validation measures. [ABSTRACT FROM AUTHOR]

In view of the ability of the three-way concept lattices to describe the correlations and hierarchical relationships among the knowledge points, this paper proposes a knowledge point navigation approach based on the three-way concept lattices for autonomous learning. First, this paper constructs the formal context of the exercises-knowledge points according to the corresponding relationship between the exercises and knowledge points; then, the three-way concept lattice generation algorithms are used to obtain the AE-concept lattice and OE-concept lattice; finally, this paper provides students with an effective autonomous learning path and knowledge points navigation Hasse diagram to achieve efficient guidance of autonomous learning. [ABSTRACT FROM AUTHOR]

• The accuracy is greatly improved after replacing SCS module with the CSC module in Shift-GCN. • Inspired by shift CNNs, we replace shift space convolution in Shift-GCN with a sparse shift and named SparseShift-GCN. • The accuracy of algorithm was further improved after introduction of OHEM into SparseShift-GCN. Skeleton-based action recognition is widely used due to its advantages of lightweight and strong anti-interference. Recently, graph convolutional networks (GCNs) have been applied to action recognition and have made breakthrough progress. The shift convolution operator can effectively replace the spatial convolution and greatly reduce the computational complexity of the algorithm. This article first applies the Conv-Shift-Conv (CSC) module and the Shift-Conv-Shift-Conv (SC2) module to replace the Shift-Conv-Shift (SCS) module in spatial graph convolution of Shift-GCN respectively. This design can reorder the shifted channels more effectively. The experimental results show that the CSC module has the best effect and effectively improves accuracy of model. After that, this article proposes to replace the shift module in the original Shift-GCN with a sparse shift module and named SparseShift-GCN. This structure can reduce the redundancy of features, prevent overfitting and improve the generality of the model. Based on the improvement in the previous step, better results have been achieved. Finally, this paper uses OHEM Loss and Weighted Loss to carefully design the loss function of the model and introduces it into the model proposed in this paper. Experimental results show that OHEM Loss further improves the accuracy of algorithm. After a series of improvements, our proposed model has improved the accuracy of 4 different streams to varying degrees, which improves the overall performance of the network. [ABSTRACT FROM AUTHOR]

• The two change detection algorithms proposed in this paper use KFCM gradient clustering algorithm. • KFCM algorithm is a classic clustering algorithm in unsupervised clustering, which can effectively cluster most of the data. • We will study how to use the special features of the image to complete the clustering of the difference maps. In recent years, computer vision, especially deep learning, has been widely used in various fields. Through the deep learning aerial image detection gradient clustering algorithm automatic recognition, it can solve the limitations of manual shooting by humans, can shoot from a high altitude to a panoramic view of a specific area, and provide a more comprehensive solution. The traditional forest resource management and management work is mainly carried out by forestry personnel to carry out a large number of investigations and investigations on the forest. This method not only consumes a lot of manpower and material resources, but also does not have real-time nature. It is difficult to deal with all kinds of forest management. Problems, causing unnecessary losses. In this regard, this paper proposes an aerial image change detection algorithm based on H-KFCM, and designs related experiments to verify and demonstrate the performance of the algorithm. In this paper, we conduct a parallel study based on deep learning on the gradient clustering algorithm of deep learning in aerial image processing. By using CUDA (Compute Unified Device Architecture) to perform large-scale parallel processing of aerial data. Can greatly shorten the time to obtain results, improve the efficiency of relevant personnel. Experiment analysis. It can be seen from the results that the deep learning parallelization program implemented in this paper has a faster calculation speed and uses less time in high-resolution images, and has a good acceleration ratio compared to the CPU. [ABSTRACT FROM AUTHOR]

For the problems of inconsistent sample duration and unbalance of sample categories in the speech emotion corpus, this paper proposes a speech emotion recognition model based on Bi-GRU (Bidirection Gated Recurrent Unit) and Focal Loss. The model has been improved on the basis of learning CRNN (Convolutional Recurrent Neural Network) deeply. In CRNN, Bi-GRU is used to effectively lengthen the samples of the speech with short duration, and Focal Loss function is used to deal with the difficulties in classification caused by the imbalance of emotional categories of the samples. Through different methods for experimental comparison, weighted average recall (WAR), unweighted average recall (UAR) and confusion matrix (CM) are used as evaluation index of the algorithm. The experimental results show that the speech emotion recognition model proposed in this paper improves the recognition accuracy and the imbalance of IEMOCAP database samples, and can effectively prove that the improvement of speech emotion recognition performance is not due to the adjustment of model parameters or the change of the model topology. [ABSTRACT FROM AUTHOR]

• The scale factor is introduced to deal with the oral cavity registration of multi-source data sets. • Correntropy is introduced into the scaling registration algorithm to suppress noise and outliers interference. • Bi-directional distance is used to ensure the robustness of the proposed algorithm. In orthodontics, a patient is collected a lot of 3D oral cavity data, including oral cavity gypsum and scan data sets. To accurately measure the patient's tooth movement, this paper proposes a robust and precise isotropic scaling registration algorithm using bi-directional distance and correntropy. Firstly, because the oral cavity gypsum data sets have a lot of gypsum tumors and bubbles, which can cause the accuracy of registration results to decrease. Then, we introduce the correntropy into the traditional scaling registration model. Secondly, since unconstrained scaling registration is an ill-posed problem, bi-directional distance is used to enhance the robustness. In this way, a registration model using bi-directional distance and correntropy is established. In order to solve this problem, this paper proposes a new registration algorithm with iterative closest point. Moreover, the convergence of the algorithm is proved theoretically. Finally, the proposed algorithm is tested on the orthodontic database, and our experimental results demonstrate that our algorithm performs robust and high accuracy. [ABSTRACT FROM AUTHOR]

• A new algorithm for computing all the shortest reducts of a decision system is introduced. • Some of the most effective pruning properties for computing all reducts are adapted to compute only the shortest reducts. • Our algorithm uses binary cumulative operations and a fast candidate evaluation process unlike other algorithms. • Our proposal is the fastest in decision systems whose simplified binary discernibility matrices have medium or high density. This paper deals with the problem of computing the shortest reducts of a decision system. The shortest reducts are useful for attribute reduction in classification problems and data size reduction. Unfortunately, finding all the shortest reducts is an NP-hard problem. There are some algorithms reported in the literature to overcome the complexity of computing the shortest reducts. However, most of these algorithms relay on costly operations for candidate evaluation. In this paper, we propose a new algorithm for computing all the shortest reducts; based on binary cumulative operations over a pair-wise comparison matrix, and a fast candidate evaluation process. Binary cumulative operations save computation time by avoiding repetitive calculations. Furthermore, unlike other algorithms reported in the literature, our candidate evaluation process relays on low-cost operations which reduce the runtime in most cases. Our experiments over synthetic and real-world decision systems show that our proposal is faster than state of the art algorithms in most decision systems. [ABSTRACT FROM AUTHOR]

• Adaptively allocate computing resource to input regions for better network inference. • Patch sampling algorithm reduces redundant calculation costs in overlapping regions. • Comparable performance is achieved on two datasets by comparing with SOTA methods. [Display omitted] In this paper, we propose an entropy-dynamic resolution detection (EDRdet) method for object detection in aerial images. Most conventional object detection methods usually detect each region in aerial images directly with a fixed resolution, so that the resolution of the hard-to-detect region in the whole aerial image is not enough and that of the easy-to-detect region is not necessary. We argue that different resolutions of regions are required for efficient and accurate object detection in aerial images. Our EDRdet dynamically adjusts the resolution of each region via measuring the challenge of the detection process, therefore, our model can achieve a good trade-off between the computational cost and the accuracy effectively. Specifically, our EDRdet searches hard-to-detect regions through low-resolution global context information, and inputs higher-resolution patches to supplement lost feature at low resolution for fine-grained detection. We apply the entropy to determine the regions in aerial images required to be detected at higher resolutions, and where the entropy represents the uncertainty of the detection result. Moreover, we design a patch sampling algorithm to make the selected regions sparse to further improve the efficiency of patch generation. Extensive experiments on the DOTA and Visdrone2019 datasets verify that our EDRdet can reduce the computational cost and improve the model accuracy effectively. [ABSTRACT FROM AUTHOR]

• This paper discusses the weighted tensor nuclear norm in the framework of tensor-SVD. • The subgradient of the weighted tensor nuclear norm is studied. • The KKT condition of the proposed nonsmooth nonconvex problem is proved. In this paper, we consider the tensor completion problem, which aims to estimate missing values from limited information. Our model is based on the recently proposed tensor-SVD, which uses the relationships among the color channels in an image or video recovery problem. To improve the availability of the model, we propose the weighted tensor nuclear norm whose weights are fixed in the algorithm, study its properties and prove the Karush-Kuhn-Tucker (KKT) conditions of the proposed algorithm. We conduct extensive experiments to verify the recovery capability of the proposed algorithm. The experimental results demonstrate improvements in computation time and recovery effect compared with related methods. [ABSTRACT FROM AUTHOR]

• Optimized incremental bit-quads count in component trees. • The intuition of incremental bit-quad count in component trees correctness. • A Fast method to compute area, perimeter and Euler Number in grayscale images. • A Fast algorithm to compute continuous perimeter approximation in grayscale images. • Software applications were rewritten using attributes computed by bit-quads. Component tree is a full image representation which encodes all connected components from upper (resp. lower) level sets of a given image through the inclusion relation. Information from this representation can be used in many image processing and computational vision applications, e.g. connected filtering, image segmentation, feature extraction, among others. In general, each node of a component tree represents a connected component of a level set and stores attributes which describes features of this connected component. This paper presents a review of a previously published method to compute attributes such as area, perimeter, and number of Euler by incrementally counting patterns while traversing nodes of a component tree. This method foundation is further detailed in this paper by presenting a novel theoretical background and algorithm correctness intuition. We also present a novel approach for this algorithm showing improvements for run-time execution and precision analysis. [ABSTRACT FROM AUTHOR]

• An efficient algorithm to update non-flat and incremental attributes in morphological trees. • Concepts and properties about updating non-flat and incremental attributes in morphological trees. • Adaptations of filter rules to compute additional structures for updating non-flat and incremental attributes. • Our algorithm is suitable for improving computation of composition of attribute filters [Display omitted] Attribute Filters are powerful image simplification operators that have very good contour-preservation properties. They can be efficiently computed using morphological trees. The most common strategy to compute attribute filters using morphological trees is based on three steps: (i) tree construction: the tree is built along with its attributes; (i i) filtering: we simplify the tree by removing some of its nodes based on some attribute and a filtering rule defined on a threshold value; and (i i i) image reconstruction: this is the final phase where the tree is converted back to an image leading to an attribute filter. However, after filtering a few attributes in tree may change (we call them as non-flat attributes) and they must be updated, when other attribute filters are applied to the simplified tree again, with either a different or the same threshold value. In this paper we present an efficient algorithm to update non-flat and incremental attributes in morphological trees with low memory consumption and fast computation. [ABSTRACT FROM AUTHOR]

In this paper, regularised regression for sequential data is investigated and a new ridge regression algorithm is proposed. It uses the Aggregating Algorithm (AA) to devise an iterative version of ridge regression (IRR). This algorithm is called AAIRR. A competitive analysis is conducted to show that the guarantee on the performance of AAIRR is better than that of the known online ridge regression algorithms. Moreover, an empirical study is carried out on real-world datasets to demonstrate the superior performance over those state-of-the-art algorithms. [ABSTRACT FROM AUTHOR]

• This paper proposes a k-center algorithm estimating the center of a binary template cluster. • This paper proposes to use weighted bidirectional distance to avoid the center's convergence to zero vector. • The k-center algorithm makes hierarchical binary template tree construction and matching more efficient. • It can set the center existing in the space between the lower level clusters. To construct a hierarchical template tree of binary templates, the dissimilarity between templates was defined using distance transform, and a k-medoid algorithm was applied to select the representative of a template cluster. However, this method has a limitation in that the representative of a higher level cluster cannot exist in the space between the lower level clusters. In order to solve this problem, this paper proposes a k-center algorithm that finds a template that minimizes the distance to templates belonging to a cluster by using a genetic algorithm regarding each pixel of a binary template as a gene. The search space can be limited by randomly selecting the initial population from the templates belonging to the cluster. In particular, the weighted bidirectional distance is used as the dissimilarity between templates to prevent the cluster center from shrinking. By applying the proposed method to pedestrian silhouettes, it is possible to confirm that a leaf node similar to the given template is better detected and its performance is more stable. [ABSTRACT FROM AUTHOR]

Highlights • We propose a TT-PCA algorithm for estimating structured subspace from the data. • TT-PCA is empirically shown to be more robust to noise as compared to PCA or Tucker-PCA. • The approach is validated on Extended YaleFace Dataset B. • Storage, computation, and classification performance tradeoffs are investigated. Abstract Tensor train is a hierarchical tensor network structure that helps alleviate the curse of dimensionality by parameterizing large-scale multidimensional data via a set of network of low-rank tensors. Associated with such a construction is a notion of Tensor Train subspace and in this paper we propose a TT-PCA algorithm for estimating this structured subspace from the given data. By maintaining low rank tensor structure, TT-PCA is empirically more robust to noise as compared to PCA or Tucker-PCA. This is borne out numerically by testing the proposed approach on the Extended YaleFace Dataset B, MINIST Dataset, CIFAR-10 dataset. This paper shows that the TT-PCA methods achieve less storage requirements, and have computationally faster online implementation with improved classification performance. [ABSTRACT FROM AUTHOR]

• A lightweight CNN is designed for efficient gait recognition. • A joint knowledge distillation algorithm is proposed for boosting the performance of the simplified model. • Extensive experiments on two public datasets demonstrate the effectiveness of the proposed method. Gait recognition has made significant progress recently. However, most of existing methods utilize complicated neural networks, which lead to high computation cost. In this paper, a lightweight model named Distilled Light GaitSet (DLGS) is proposed for efficient gait recognition. More specifically, a lightweight CNN is designed for efficient computation, and a Joint Knowledge Distillation algorithm is proposed to boost the accuracy of the simplified model. Extensive experiments on the CASIA-B dataset and the OU-MVLP dataset show that the proposed DLGS can reduce the number of parameters and computation cost significantly while achieving the state-of-the-art performance. [ABSTRACT FROM AUTHOR]

• A novel PDE-constrained optimization problem is proposed for MRI denoising task. • The proposed optimization procedure computes the variable exponent and the clean image for MRI images. • The comparative results demonstrates the performance on two MRI datasets This paper investigates a novel PDE-constrained optimization model with discontinuous variable exponent p (x) identification. Since the parameter p is always related to a better approximation of the image gradient, its computation plays a critical role in preserving the image texture. Analytically, we include results on the approximation of this parameter as well as the resolution of the encountered PDE in a well posed framework. In addition, to resolve the PDE-constrained minimization problem, we proposed a modified primal-dual algorithm. Finally, numerical results are provided to compute the parameter p and also to remove high intensity of noise. The proposed algorithm simultaneously keep safe fine details and important features in medical image applications (Magnetic Resonance Images (MRI)) with numerous comparisons to show the performance of the proposed approach. [ABSTRACT FROM AUTHOR]

• Near optimal results, with a less than 5% deviation from optimal results of a DFS algorithm. • Fast execution time. • Scalable since it can deal with large data-sets in small execution time. • report tight upper-bounds for large data-sets. Graph Edit Distance (GED) problem is a well-known tool used to measure the similarity/dissimilarity between two graphs. It searches for the best set of edit operations (in terms of cost) that transforms one graph into another. Due to the NP-hardness nature of the problem, the search space increases exponentially making exact approaches impossible to use for large graphs. In this context, there is a huge need for approaches that give near-optimal results in reasonable time. In this paper, we propose a tree-based approximate approach for dealing with GED problem. It operates on a search tree that models all possible solutions of the problem. Since exploring the whole tree is impractical; this approach keeps only the best k nodes at each level of the tree for further exploration. This reduces enormously the execution time without scarifying the solution quality. Experiments using small and medium size data-sets show the low deviation of our results as compared to the optimal results of a Depth First Search algorithm. Moreover, our approach show a strong scalability potential by dealing with large data-sets in low execution time. [ABSTRACT FROM AUTHOR]

• A distributed algorithm is proposed to solve graph semi-supervised learning problem by leveraging the graph topology. • The convergence of the distributed algorithm is explicitly proved. • Numerical results verify the good performance and low cost of the distributed algorithm. Graph semi-supervised learning (GSSL) plays an important role in data classification by leveraging the similarity across the graph topology and convex optimization with Laplacian-based regularization. However, the current algorithm to solve the problem is centralized approach calling for heavy computational cost, particularly when the data is of large volume. In this paper, an innovate distributed algorithm is proposed to solve the problem, which is based on the decomposition of the similar graph. Contrary to the centralized approach, the distributed algorithm only requires the neighboring information for solving the optimization. It is proved that difference between the solutions of the distributed algorithm and centralized counterpart is upper bounded. We apply the proposed algorithm to both the synthetic and real-world datasets. The numerical results verify the effectiveness of the proposed distributed algorithm. [ABSTRACT FROM AUTHOR]

• A new branch is added to process structured data. • The objective function is modified to adapt to the new branch. • Detailed comparisons are made between our algorithm and the other classical models. The semi-supervised learning(SSL) was proposed to deal with the situation that only a few samples were labeled, so how to make the most use of the existing samples is crucial. In general, we apply data augmentation methods, like Generative Adversarial Networks(GAN), to increase the number of data when facing unstructured data. However, things get totally different with structured data, the continuity of neural networks limits their use in category variables. In this paper, we propose a semi-supervised Embedding GAN(EmGAN) to solve that problem. We add an embedding layer before the discriminator to better characterize category features and design a new loss function to further train our model. Moreover, the structures of the generator and discriminator are modified to match structured data. With the experiments of nonparametric statistical test, EmGAN shows its advantages in processing structured samples. [ABSTRACT FROM AUTHOR]

Many applications, such as robotics, are increasingly utilizing Reinforcement Learning (RL). The current implementation of RL typically assumes that the state update from the previous actions happens instantaneously, and thus can be used for making future decisions. However, this may not always be true. When the state update is not available, the decision is taken partly in the blind since it cannot rely on the current state information. This paper proposes an approach, where the delay in the knowledge of the state can be used, and the decisions are made based on the available information which may not include the current state information. One approach could be to include the actions after the last-known state as a part of the state information, however, that leads to an increased state-space making the problem complex and slower in convergence. The proposed algorithm gives an alternate approach where the state space is not enlarged, as compared to the case when there is no delay in the state update. Evaluations on the control environments further illustrate the improved performance of the proposed algorithm. [ABSTRACT FROM AUTHOR]

• The proposed method only needs a single discrete input parameter. • The proposed method has a robust performance in the different density scenario. • The proposed method can automatically detect the number of clusters. • We adapt the cluster stability for our method and find a new way to calculate it. The density-peak clustering (DPC) method (Rodriguez and Laio, 2014) clusters the data efficiently by fast searching density peaks. Recently, an improved DPC algorithm named 3DC method (Liang and Chen, 2016) was proposed for automatically detecting the correct structure of the clusters. However, it is difficult to select correct parameters for the DPC and 3DC methods and the local property of data set can't be revealed due to their global density assumption in some scenarios. To overcome this drawback, the K-nearest neighbor (KNN) framework is adapted for defining the density of the DPC method. Nevertheless, such KNN-based methods can't automatically detect the number of the clusters compared with the 3DC method. In this paper, an automatic clustering method is proposed, which needs only a discrete input parameter. Meanwhile, by utilizing the cluster stability for the Chameleon framework, the proposed method can automatically detect the correct structure of the clusters. The experimental results on the synthetic and real world data demonstrate that the proposed method has a more robust performance. Besides, the proposed method is robust to the choices of the input parameter. [ABSTRACT FROM AUTHOR]

• Optimizes the clustering result and the common representation subspace simultaneously across multiple views. • Untangle heavily mixed clusters by optimizing a single continuous objective. • Without the requirement of the number of clusters given in advance. • Not prone to stick into bad local minima even with outliers in data. This paper proposed a novel Robust Multi-View Continuous Subspace Clustering (RMVCSC) algorithm, which can untangle heavily mixed clusters by optimizing a single continuous objective. The proposed objective uses robust estimators to automatically clip specious inter-cluster connections while maintaining convincing intra-cluster correspondences in the common representation subspace learned from multiple views. The common representation subspace can reveal the underlying cluster structure in data. RMVCSC is optimized in an alternating minimization scheme, in which the clustering result and the common representation subspace are simultaneously optimized. Since different views can describe distinct perspectives of input data, the proposed algorithm has more accurate clustering performance than conventional algorithms by exploring information among multi-view data. In other words, the proposed algorithm optimizes a novel continuous objective in the simultaneously learned common representation subspace across multiple views. By using robust redescending estimators, the proposed algorithm is not prone to stick into bad local minima even with outliers in data. This kind of robust continuous clustering methods has never been used for multi-view clustering before. Moreover, the convergence of the proposed algorithm is theoretically proved, and the experimental results show that the proposed RMVCSC can outperform several very recent proposed algorithms in terms of clustering accuracy. [ABSTRACT FROM AUTHOR]

• We propose a DSNnet optimization model with non-convex equality constraints for unsupervised representation learning. • We design a neural network based algorithm to solve the proposed DSNnet model. • We introduce a novel similarity measurement between input data and learned features as a regularization term of DSNnet. Deep Semi-NMF (DSN), which learns hierarchical representations by stacking multiple layers Semi-NMF, shows competitive performance in unsupervised data analysis. However, the features learned from DSN always lack of representativity and discriminativity. In this paper, we build a novel Deep Semi-NMF network (DSNnet) to address the issues of DSN. Specifically, DSNnet contains multiple fully-connected layers, in which the activation function of each layer adopts Smoothly Clipped Absolute Deviation (SCAD). The non-negative hidden features are computed forwardly, while the network parameters are updated by the stochastic gradient descent method. Moreover, to enhance the discriminativity of features, we suggest simultaneously minimizing the reconstruction error of input and output, and maximizing the similarity between input and learned features. The proposed similarity measurement, which consists of global geometric similarity and local pointwise similarity, encourages the compactness between similar points and separateness between dissimilar points in the feature space, and is beneficial to preserve intrinsic information of original data. Extensive experiments conducted on several datasets illustrate the superiority of the proposed approach in comparison with state-of-the-art methods. [ABSTRACT FROM AUTHOR]

• A triple cross-domain collaborative filtering recommendation method is proposed. • An extended codebook construction algorithm is designed. • A transfer learning method based on extended codebook is presented. • Empirical results show the proposed method is superior to state-of-the-art methods. Recently, data sparsity is still one of the critical problems faced by recommendation systems. Although many existing methods based on cross-domain can alleviate it to a certain extent, these methods only use the information of single-domain (e.g., user-side, item-side and rating-side) or dual-domain (e.g., user-rating-side, user-item-side and item-rating-side) to make recommendations, which results in performance degradation. In this paper, we propose a triple cross-domain collaborative filtering method to alleviate data sparsity, named TCD-CF. In TCD-CF method, the triple-side intrinsic characteristics are first obtained by using the joint nonnegative matrix factorization to integrate the user-side, item-side and rating-side domain knowledge. Then the extended codebook (as knowledge to transfer) based on these intrinsic characteristics is constructed by using the orthogonal nonnegative matrix tri-factorization. Finally, the codebook-based transfer method for cross-system CF is applied into the source domain and target domain to predict the missing ratings and perform recommendation in the target domain. Extensive experiments on two real-world datasets demonstrate that the proposed method outperforms the state-of-the-art methods for the cross-domain recommendation task. [ABSTRACT FROM AUTHOR]

• Propose fast novel hard clustering algorithm for multi-type relational data. • Extend the popular NNDSVD method initialisation of our algorithm. • Propose internal performance clustering measure for assessing cluster similarity. Several cyber-security data sources are collected in enterprise networks providing relational information between different types of nodes in the network, namely computers, users and ports. This relational data can be expressed as adjacency matrices detailing inter-type relationships corresponding to relations between nodes of different types and intra-type relationships showing relationships between nodes of the same type. In this paper, we propose an extension of Non-Negative Matrix Tri-Factorisation (NMTF) to simultaneously cluster nodes based on their intra and inter-type relationships. Existing NMTF based clustering methods suffer from long computational times due to large matrix multiplications. In our approach, we enforce stricter cluster indicator constraints on the factor matrices to circumvent these issues. Additionally, to make our proposed approach less susceptible to variation in results due to random initialisation, we propose a novel initialisation procedure based on Non-Negative Double Singular Value Decomposition for multi-type relational clustering. Finally, a new performance measure suitable for assessing clustering performance on unlabelled multi-type relational data sets is presented. Our algorithm is assessed on both a simulated and real computer network against standard approaches showing its strong performance. [ABSTRACT FROM AUTHOR]

• Three-way concept stability and its properties. • Algorithm for the computation of three-way concept stability. • A case study on natural language generation scenario. Three-way concept analysis (3WCA) has been an emerging and important methodology for knowledge discovery and data analysis. Particularly, 3WCA can efficiently characterize the information of "jointly possessed" and "jointly not possessed" compared to the classical formal concept only can describe common attributes owned by objects. This property, typical of 3WCA has a huge potential in the field of Natural Language Generation (NLG). However, the construction of a three-way concept lattice is proved as an NP-complete problem and even harder than the construction of conventional concept lattice. This could negatively affect the use of 3WCA for NLG in real contexts. Hence, it is necessary to prune the three-way concept lattice and extract more interesting three-way concepts for knowledge acquisition. To this end, this paper defines the stability of a three-way concept and analyzes the relevant properties. An efficient computational algorithm for calculating the stability of three-way concepts is developed and evaluated by an experiment. In addition, a case study on NLG is conducted for demonstrating the applicability of the proposed technique. [ABSTRACT FROM AUTHOR]

This paper examines the issues of constrained clustering and active selection of clustering constraints in a unified approach. A fuzzy clustering method specially crafted to deal with non-spherical clusters and explicit pairwise constraints is proposed in this paper as a core clustering method. An active method for constraints selection is embedded into the core clustering method for querying beneficial constraints during clustering. The proposed approach has two major advantages relative to traditional methods. First, it considers the dependency of constraints effectiveness on the clustering algorithm by unifying both clustering and constraints selection in a uniform, principled framework. Second, a constraints selection method is embedded into the core clustering method based on the fact that constraints will be more useful if they are selected according to the current state of clustering. Experiments conducted on synthetic and real-world datasets show the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

• A scene image and human skeleton based dual-stream model is proposed. • A sparse sampling and video-level scene image classification method is adopted. • Spatio-temporal graph convolution is used for human skeleton feature extraction. • The proposed model has advantage of robustness to optical flow change. The dual stream-based human action recognition model offers the advantage of high recognition accuracy, but the algorithm is less robust in case of lighting changes. The human skeleton has a strong ability to express human behavior and actions; however, the scene information is ignored. Drawing on the idea of the dual-stream model, this paper proposes a human skeleton and scene image-based dual-stream model for human action recognition. The motion features are extracted through the spatio-temporal graph convolution of the human skeleton, and a scene recognition model is proposed based on the sparse frame sampling of video and video-level consensus strategy to process the scene video and gather the visual scene information. The proposed model exploits the advantages of skeleton information in motion expression and the superiority of the image in scene presentation. The scene information and spatio-temporal graph convolution-based human skeleton limbs are fused complementarily to achieve human action recognition. Compared to the conventional optical flow-based dual-stream action recognition method, this model is verified by experimenting under unstable light conditions, and the performance of human action recognition is robust and promising. [ABSTRACT FROM AUTHOR]

• A valid user modeling method which combines stable centroids and centroid fluctuation ranges. • A data cleaning algorithm in order to remove abnormal data. • A fixed centroid clustering algorithm by using the stable cluster centroids as the initial centroids. • An authentication method based on fluctuation ranges of centroid positions. User authentication of mobile devices is an important means to protect data security and user privacy. Low overhead, high accuracy and continuous authentication are challenging problems in user authentication. Aiming at the disadvantages of current authentication methods based on keystroke dynamics such as low accuracy and one-time authentication, this paper proposes a new authentication method named UIKI (User Identity authentication method based on clusters of Keystroke time Intervals). UIKI consists of the valid user modeling phase and the runtime user authentication phase. In the valid user modeling phase, UIKI uses a clustering algorithm to find the stable centroids and the fluctuation range of a valid user's centroid positions. In the runtime user authentication phase, UIKI clusters the data to be authenticated with the stable centroids as the initial centroids, and compares the results of clustering with the stable centroids and the centroid fluctuation range of the valid user to determine whether the input data are from the valid user. Experimental results prove that UIKI has the average FAR (False Accept Rate) of 0.082 and the average FRR (False Reject Rate) of 0.052, which can effectively authenticate a user's identity. UIKI has the advantages of high accuracy, low overhead and continuous authentication, which is suitable for the user authentication of mobile devices. [ABSTRACT FROM AUTHOR]

To help human markers mark many answers in the form of online handwritten mathematical expressions (OHMEs), this paper proposes bag-of-features for clustering OHMEs. It consists of six levels of features from low-level pattern features to high-level symbolic and structural features obtained from a state-of-the-art OHME recognizer. Then, it introduces distance-based representation (DbR) to reduce the dimensionality of our proposed feature spaces. Moreover, it presents a method for combining the proposed features to improve the performance. Experiments using the k-means++ algorithm are conducted on a set of 3,150 OHMEs (Dset_50) and an answer dataset (Dset_Mix) of 200 OHMEs intermixed between real patterns and synthesized patterns for each of 10 questions. When the number of clusters is set as the true number of categories, the best purity around 0.99 is produced by bag-of-symbols with DbR for Dset_50, which is better than state-of-the-art methods for clustering offline patterns converted from their OHMEs. The combination of both low-level and high-level features with DbR achieves a purity of around 0.777, increases to more than 0.90 and reduce the marking cost by more than 0.35 point than manually marking OHME answers by adjusting the number of clusters for Dset_Mix. • Bag-of-features for clustering handwritten mathematical answers written on tablet. • Low-level image-based features and high-level recognition-based features. • Weighted combination enhances performance of the clustering. • We achieved a purity of around 0.777 on an answer dataset. • Purity increased to more than 0.90 by adjusting the number of clusters. [Display omitted] [ABSTRACT FROM AUTHOR]

In this paper, we propose a new unsupervised and simple approach to local symmetry detection of ribbon-like structure in natural images. The proposed model consists in quantifying the presence of a partial medial axis segment, existing between each pair of (preliminary detected) line segments delineating the boundary of two textured regions, by a set of heuristics related both to the geometrical structure of each pair of line segments and its ability to locally delimit a homogeneous texture region in the image. This semi-local approach is finally embedded in a two-step algorithm with an amplification step, via a Hough-style voting approach achieved at different scales and coordinate spaces which aims at determining the dominant local symmetries present in the image and a final denoising step, via an averaging procedure, which aims at removing noise and spurious local symmetries. The experiments, reported in this paper and conducted on the recent extension of the Berkeley Segmentation Dataset for the local symmetry detection task, demonstrate that the proposed symmetry detector performs well compared to the best existing state-of-the-art algorithms recently proposed in the literature. [ABSTRACT FROM AUTHOR]

Real-world data are usually noisy, causing many machine-learning algorithms to overfit their data. Various Instance Reduction (IR) techniques have been proposed to filter out noisy instances and clean the data. This paper presents Partial Instance Reduction (PIR) or partial outlier elimination techniques. Unlike IR techniques, which eliminate all suspicious instances, PIR techniques partially eliminate a suspicious instance by eliminating some of its attribute values. If this fails to change the status of an instance from outlier to normal, the entire instance is eliminated. The main advantage of partial elimination is that it allows us to retain significant parts of instances, which is particularly useful when the training data is scarce. This paper compares PIR and IR techniques using 50 benchmark data sets, both with and without noise. Our empirical results show that PIR techniques significantly outperform the IR techniques on many benchmark datasets. Whereas IR techniques eliminate a large number of instances that are not outliers, PIR techniques manage to save parts of these instances that are useful for classification. [ABSTRACT FROM AUTHOR]

• Efficient quantification based clustering. • Clustering of functional data. • Manhattan distance. In this paper we propose a simple new algorithm to perform clustering, based on the Alter algorithm proposed in [1] but lowering significantly the algorithmic complexity with respect to the number of clusters. An empirical study states the relevance of our iterative process and a confrontation on simulated multivariate and functional data shows the benefits of our algorithm. [ABSTRACT FROM AUTHOR]

• Comprehensive study of attribution with mixed media. • A more efficient mixed-media attribution algorithm with higher performance. • An efficient and more accurate scaling factor search method. Photo Response Non-Uniformity (PRNU) based source camera attribution is an effective method to determine an image or a video's origin camera. However, modern devices, especially smartphones, capture images and videos at different resolutions using the same sensor array, PRNU attribution can become ineffective as the camera fingerprint and query object can be misaligned. While capturing visual objects (either image or video), cameras may use different in-camera operations as well as they may use different parts of the sensor. In this paper, we investigate the problem of source camera attribution of a visual object by doing a thorough investigation of a comprehensive dataset, NYUAD Mixed Media Dataset. This investigation takes many factors into accounts, such as the fact that visual objects may have been captured using different resolution and aspect ratios. Furthermore, the visual objects may use different regions of the sensor, including the usage of boundary pixels for videos. Taking these various cases into account, we propose an efficient search which not only gives the state-of-the-art results but also performs significantly faster compared to existing methods. [ABSTRACT FROM AUTHOR]

• A remote sensing image scene classification algorithm base on neural architecture search (NAS) is proposed. • A search strategy is proposed to search for the most appropriate neural architecture in the pre-defined search space. • A performance estimation strategy to evaluate the performance of search strategy. • The proposed method saves time and manpower while achieves better accuracy compared with the manually design method. Remote sensing image scene classification (RSISC) is one of the bases of visual question answering for remote sensing data (RSVQA). In the conventional deep learning based solutions of RSISC, domain experts have to manually design the neural architecture, which is costly in both time and manpower. In this paper, AutoRSISC, a high resolution remote sensing image scene classification method based on neural architecture search (NAS) is proposed. AutoRSISC algorithm samples the neural architecture in a certain proportion to reduce the redundancy in the search space which is based on the continuous relaxation of the neural architecture representation. Edge normalization is introduced to make architecture search more efficient. The conventional deep learning approaches take days or more just to manually design the appropriate neural architecture according to the current data set. The experimental results show that our method saves time and manpower compared with the existing manually designed RSISC methods. Our AutoRSISC algorithm took 7.6 h from the automatic design of the most appropriate neural architecture to the end of all experiments according to the UCM data set, and the classification accuracy rate of the final test set reached 97.85%. And our AutoRSISC algorithm took 101.7 h from the automatic design of the most appropriate neural architecture to the end of all experiments according to the NWPU45 data set, and the classification accuracy rate of the final test set reached 94.66%. [ABSTRACT FROM AUTHOR]

• A novel method for the removal of salt-and-pepper noise using information set concept is proposed. • The proposed noise removal filter is capable of reducing both low and high noise densities while preserving fine details. • The experiments are performed on the standard dataset and also on medical and real images. • A comparative analysis with the state-of-the-art methods is done. • The proposed filter provides the best qualitative and quantitative results. An efficient filtering algorithm is required to remove noise and simultaneously protect fine details and important features in the medical images. In this paper, a noise adaptive information set based switching median (NAISM) filter is proposed for the removal of impulse noise. NAISM filter is inspired from fuzzy switching median filter and works on the concept of information sets. Information sets are derived from fuzzy sets to deal with the uncertainty. It works in two phases; first phase identifies noisy pixels and second applies filtering based on an adaptive switching criterion. It is by virtue of this switching criterion and the local effective information surrounding the noisy pixel, the best calculated value replaces the noisy pixel in the selected window. The proposed information set based filter is capable of removing both low and high noise densities and can preserve image details better than the fuzzy filter. The applicability of the proposed filter is demonstrated on different datasets including Berkeley Segmentation Dataset (BSD), medical and real images. The qualitative and quantitative results demonstrate the effectiveness of the proposed approach in suppressing noise over the existing approaches. [ABSTRACT FROM AUTHOR]

• Embedding capacity is increased by embedding n (n = 2,3,4...) secret bits per block. • After decryption, secret message is extracted and cover image is recovered using spatial correlation of image. • The proposed method demonstrates higher PSNR values as compared to Zhang [12] and Young et al. [17] for all test images. Earlier joint EIRDH (Encrypted Image Reversible Data Hiding) techniques divided cover image into equal sized blocks and embedded one secret bit per block and after decryption of stego image with same key as encryption key, secret message is extracted through data hiding key and original cover image is recovered using spatial correlation of the image. After carrying out a feasibility analysis, improved block based joint EIRDH algorithm is employed in this paper which embedded n (n = 2 , 3 , 4.....) secret bits per block by dividing blocks of same size (4 × 4, 8 × 8, 16 × 16, 32 × 32.....)into n sub-blocks. Optimal visual quality and enhanced embedding rate are acquired by the proposed scheme. Test results and correlations are exhibited to outline the viability and focal points of the proposed technique with conventional ones. [ABSTRACT FROM AUTHOR]

• An effective approach to fill large gap(s) in univariate time series is proposed. • Apply DTW algorithm to find similar pattern(s) to the sub-sequence before the gap. • Combine shape-features extraction and DTW methods to reduce insignificant solutions. • Quantitative and visual performance of 6 methods are compared on 8 time series. • We implemented all methods using R language. Time series with missing values occur in almost any domain of applied sciences. Ignoring missing values can lead to a loss of efficiency and unreliable results, especially for large missing sub-sequence(s). This paper proposes an approach to fill in large gap(s) within time series data under the assumption of effective information. To obtain the imputation of missing values, we find the most similar sub-sequence to the sub-sequence before (resp. after) the missing values, then complete the gap by the next (resp. previous) sub-sequence of the most similar one. Dynamic Time Warping algorithm is applied to compare sub-sequences, and combined with the shape-feature extraction algorithm for reducing insignificant solutions. Eight well-known and real-world data sets are used for evaluating the performance of the proposed approach in comparison with five other methods on different indicators. The obtained results proved that the performance of our approach is the most robust one in case of time series data having high auto-correlation and cross-correlation, strong seasonality, large gap(s), and complex distribution. [ABSTRACT FROM AUTHOR]

• Rectification of problems due to sudden illumination changes and proper alignment of feature set for an effective FER. • Isolation of foreground from the background of an image to facilitate the facial key points extraction. • Elimination of unwanted noise and smoothen by using AMF filtering technique. • MATP-based texture pattern and DESURF-LOP-based facial key points to the FER outperform the traditional methods. • PPCSO-based feature selection and LSTM-CNN based classification recognize the expressions accurately. Facial Expression Recognition (FER) plays the vital role in the Human Computer Interface (HCI) applications. The illumination and pose variations affect the FER adversely. The projection of complex 3D actions on the image plane and the inaccurate alignment are the major issues in the FER process. This paper presents the novel Multi-Angle Optimal Pattern-based Deep Learning (MAOP-DL) method to rectify the problem from sudden illumination changes, find the proper alignment of a feature set by using multi-angle-based optimal configurations. The proposed method includes the five major processes as Extended Boundary Background Subtraction (EBBS), Multi-Angle Texture Pattern+STM, Densely Extracted SURF+Local Occupancy Pattern (LOP), Priority Particle Cuckoo Search Optimization (PPCSO) and Long Short-Term Memory -Convolutional Neural Network (LSTM-CNN). Initially, the EBBS algorithm subtracts the background and isolates the foreground from the images which overcome the illumination and pose variation. Then, the MATP-STM extracts the texture patterns and DESURF-LOP extracts the relevant key features of the facial points. The PPCSO algorithm selects the relevant features from the MATP-STM feature set to speed up the classification. The employment of LSTM-CNN predicts the required label for the facial expressions.The major key findings of the proposed work are clear image analysis, effective handling of pose/illumination variations and the facial alignment. The proposed MAOP-DL validates its effectiveness on two standard databases such as CK+ and MMI regarding various metrics and confirm their assurance of wide applicability in recent applications. [ABSTRACT FROM AUTHOR]

• A distributed discrete-time optimization algorithm is designed. • The communication can be reduced over network via event-triggered mechanism. • The Zeno behavior is naturally excluded based on discrete iteration scheme. • The optimal value is obtained with discrete exponential convergence rate. In this paper, a distributed discrete-time event-triggered algorithm is proposed to deal with the economic dispatch problem with equality constraint. The communication can be reduced and the energy of systems can be saved by adopting event-triggered communication mechanism. The Zeno behavior is naturally excluded based on discrete iteration scheme. Moreover, the proposed algorithm has been proved to be exponentially convergent with the aid of convex optimization and Lyapunov stability theory that the optimal value is obtained with discrete exponential convergence rate. Finally, the effectiveness of the proposed algorithm is verified via a numerical example. [ABSTRACT FROM AUTHOR]

• The greedy AutoAugment is proposed to find the best augmentation policies. • It reduces the exponential growth of the number of possible trials to linear growth. • The algorithm is computationally efficient and can concatenate many sub-policies. • The greedy approach helps the algorithm to increase the accuracy of the network. A major problem in data augmentation is to ensure that the generated new samples cover the search space. This is a challenging problem and requires exploration for data augmentation policies to ensure their effectiveness in covering the search space. In this paper, we propose Greedy AutoAugment as a highly efficient search algorithm to find the best augmentation policies. We use a greedy approach to reduce the exponential growth of the number of possible trials to linear growth. The Greedy Search also helps us to lead the search towards the sub-policies with better results, which eventually helps to increase the accuracy. The proposed method can be used as a reliable addition to the current artifitial neural networks. Our experiments on four datasets (Tiny ImageNet, CIFAR-10, CIFAR-100, and SVHN) show that Greedy AutoAugment provides better accuracy, while using 360 times fewer computational resources. [ABSTRACT FROM AUTHOR]

• Automatic reconstruction of destroyed frescoes. • Efficiency with respect to a large number of irregular and spurious fragments. • Color-constrained matching between keypoints. • Analysis of the fresco and fragment features impacting the performance. Virtually recomposing destroyed frescoes is of great importance for heritage conservation. Given a digitized fresco image and a digitized set of fragments, such a problem is challenging due to the potentially large number of fragments, their irregular shape, uniqueness and non-overlapping constraints, the possible absence of fragments and the possible presence of small, homogeneous, eroded and/or spurious fragments. To cope with these specific features, we propose in this paper a fast and efficient non-dense approach benefiting from previous developments in pattern matching. Preliminary experiments led on simulations exhibit a mean accuracy above 90% with a mean translation error of less than 4 pixels and a mean orientation error of about 1 degree. An analysis of fresco and fragment features impacting the algorithm is also provided. Compared to a dense approach and the recent DeepMatch approach, the proposed one remains competitive both in running time and accuracy. [ABSTRACT FROM AUTHOR]

• A novel weighted capsule fuzzy gaussian model (WCFGM) routing algorithm is proposed to improve the original EM routing. • WCFGM routing prohibits atypical child capsules to contaminate the parent capsules. • A pose loss is introduced to provide the best inter-class separation. • The ability of pattern classification is improved in terms of accuracy. Capsule network (CapsNet) is a novel architecture that takes into account the hierarchical pose relationships between object parts, which had achieved desirable results on image classification. EM-Routing (EM-R) used in CapsNet is the process of assigning child capsules (parts) to each parent capsule (objects) based on a level of agreement, which is similar to the fuzzy clustering process. However, CapsNet still struggles with backgrounds and the presence of noise. In this paper, a new routing algorithm based on a weighted capsule fuzzy gaussian model (WCFGM-R) and a pose loss function are proposed. The proposed algorithm aims to prohibit atypical child capsules from contaminating the parent capsules by incorporating the activations of capsules in a lower layer as weights that play the role of precision. The pose loss provides the best inter-class separation and improves the ability of pattern classification. Indeed, the experimental analyses demonstrate that CapsNet with WCFGM-R outperforms the CapsNet with EM-R in which it shows excellent results on three datasets (MNIST-bg-img, MNIST-bg-rnd, and CIFAR10). [ABSTRACT FROM AUTHOR]

• Differentiable reformulation of the k -Means problem in a learned embedding space. • Proposition of an alternative to pretraining based on deterministic annealing. • Straightforward training algorithm based on stochastic gradient descent. • Careful comparison against k -Means-related and deep clustering approaches. We study in this paper the problem of jointly clustering and learning representations. As several previous studies have shown, learning representations that are both faithful to the data to be clustered and adapted to the clustering algorithm can lead to better clustering performance, all the more so that the two tasks are performed jointly. We propose here such an approach for k -Means clustering based on a continuous reparametrization of the objective function that leads to a truly joint solution. The behavior of our approach is illustrated on various datasets showing its efficacy in learning representations for objects while clustering them. [ABSTRACT FROM AUTHOR]

• Propose a weighted hybrid multi-view fusion method for the semi-supervised classification problem. • Introduce Variant Alternating Splitting Augmented Lagrangian Method to solve the rank consistency problem. • Design an efficient iterative algorithm to optimize the objective function. This paper proposes a weighted hybrid multi-view fusion method for the semi-supervised classification problem. Instead of getting access to the features from different views directly, this method utilizes the square losses of the multi-view classifiers to exploit the between-view relationship, which preserves the privacy of data. Considering the different prediction capability of classifiers on multiple views, an objective function with the constraint of rank consistency is constructed to weight view-specific learners adaptively, where the constraint makes each view-specific learner improve its performance by exploring the predicted results of other learners. Furthermore, an iterative algorithm based on the Variant Alternating Splitting Augmented Lagrangian Method (VASALM) and the quadratic programming method is developed to optimize the objective function. Experimental results on different real-world datasets demonstrate the effectiveness of the proposed method for multi-view learning. The experiments also analyze parameter sensitivity and convergency of the optimization algorithm. [ABSTRACT FROM AUTHOR]

• A supervised classification based MRF model is proposed for depth map up-sampling. • Low-resolution depth segmentation is used to supervise color image classification. • Classification result is further introduced in the design of MRF energy function. • The designed MRF energy function is optimized with a gradient descent algorithm. • Comparisons with the state-of-the-art show the superiority of the proposed SC-MRF model. In this paper, a Supervised Classification assisted Markov Random Field (SC-MRF) model is proposed for generating high-quality up-sampled depth maps. The proposed model aims to reduce depth bleeding and depth confusion artifacts that can be produced at boundary regions of the up-sampled depth maps. In the proposed model, segmentation of low-resolution (LR) depth map is first used to supervise the classification of corresponding high-resolution (HR) color image. With this supervised classification, not only can the depth edges be retained, but redundant textures in the HR color image can be omitted. The classification result is then introduced into the design of a MRF energy function, and the final up-sampled depth map is obtained by optimizing this energy function with the gradient descent algorithm. For simplicity, classical K -means clustering is adopted to segment the LR depth map into several classes, and a feature-based K -nearest neighbour (K -NN) method is utilized for the supervised classification. With the proposed SC-MRF model, interaction between depths of different classes will be strongly suppressed, meaning depth edges are well preserved. Comparisons with the state-of-the-art demonstrate the strong performance of the proposed method both visually and by quantitative evaluation. [ABSTRACT FROM AUTHOR]

• A novel Particle swarm optimization based algorithm (PSO-GES), is introduced. • A guided exploration strategy in order to generate high-quality rules, is proposed. • A new fitness funtion for obtain the fitness value in a shorter runtime, is introduced. • PSO-GES uses a summary matrix with a smaller number of rows than the original database. • PSO-GES mines a set of better quality rules than the association rules mining algorithms compared. Association rule mining is one of the most important and active research areas in data mining. In the literature, several association rule miners have been proposed; among them, those based on particle swarm optimization (PSO) have reported the best results. However, these algorithms tend to prematurely fall into local solutions, avoiding a wide exploration that could produce even better results. In this paper, an algorithm based on PSO, called PSO-GES, for mining association rules using a Guided Exploration Strategy is introduced. Our experiments, over real-world transactional databases, show that our proposed algorithm mines better quality association rules than the most recent PSO-based algorithms for mining association rules of the state of the art. [ABSTRACT FROM AUTHOR]

• A new graph-based data classification method is presented. • The method can be applied to both semi-supervised and unsupervised learning tasks. • Some of its properties allow it to perform well with small labeled training sets. • It is unconditionally stable, incorporates class size information and efficient. • Experiments are performed on classification of 3D sensory data such as point clouds. Data classification, where the goal is to divide data into predefined classes, is a fundamental problem in machine learning with many applications, including the classification of 3D sensory data. In this paper, we present a data classification method which can be applied to both semi-supervised and unsupervised learning tasks. The algorithm is derived by unifying complementary region-based and edge-based approaches; a gradient flow of the optimization energy is performed using modified auction dynamics. In addition to being unconditionally stable and efficient, the method is equipped with several properties allowing it to perform accurately even with small labeled training sets, often with considerably fewer labeled training elements compared to competing methods; this is an important advantage due to the scarcity of labeled training data. Some of the properties are: the embedding of data into a weighted similarity graph, the in-depth construction of the weights using, e.g., geometric information, the use of a combination of region-based and edge-based techniques, the incorporation of class size information and integration of random fluctuations. The effectiveness of the method is demonstrated by experiments on classification of 3D point clouds; the algorithm classifies a point cloud of more than a million points in 1–2 min. [ABSTRACT FROM AUTHOR]

• The integer-valued vector representing a candidate solution encodes all dataset features. • The feature subset size is determined by using an additional element in the vector. • Feature relevance is represented through its relative position in the vector. • A permutation-matrix-based mutation operator can be used to create new solutions. • A simple repair-based recombination operator is used to ensure feasible solution creation. This paper describes a permutational-based Differential Evolution algorithm implemented in a wrapper scheme to find a feature subset to be applied in the construction of a near-optimal classifier. In this approach, the relevance of a feature chosen to build a better classifier is represented through its relative position in an integer-valued vector, and by using a permutational-based mutation operator, it is possible to create new feasible candidate solutions only. Furthermore, to provide a controlled diversity rate in the population, a straightforward repair-based recombination operator is utilized to evolve a population of candidate solutions. Unlike the other approaches in the existing literature using integer-valued vectors and requiring a predefined subset size, in this approach, this size is determined by an additional element included in the encoding scheme, allowing to find an adequate feature subset size to each specific dataset. Experimental results show that this approach is an effective way to create more accurate classifiers as they are compared with those obtained by other similar approaches. [ABSTRACT FROM AUTHOR]