Network Classification Problem Research Articles

Data-Driven DOA Estimation Methods Based on Deep Learning for Underwater Acoustic Vector Sensor Array

Abstract Direction of arrival (DOA) estimation is a fundamental problem in underwater acoustic vector sensor array signal processing. Because of the advantages of deep learning technology, this paper proposes two categories of data-driven DOA estimation methods for underwater acoustic vector sensor array, which transform the DOA estimation problem into a neural network classification problem. Specifically, one is the DOA estimation method of convolutional neural network based on teacher-student noise reduction (TS-CNN), which considers the covariance matrix as the training data set; the other is a DOA estimation method based on long-short term memory network and attention mechanism (LSTM-ATT), which applies the time-domain signal as the training data set. The experimental simulation results show that: 1) when the number of array elements is small, the accuracy of the DOA estimation method based on TS-CNN is equivalent to that of traditional methods, and it can effectively suppress the influence of noise when the signal-to-noise ratio (SNR) is low; 2) the accuracy of DOA estimation method based on LSTM-ATT is much higher than that of traditional Multiple Signal Classification method, especially in the case of low SNR, which also proves the importance of temporal characteristics for DOA estimation in a real environment.

Joint Inference of Diffusion and Structure in Partially Observed Social Networks Using Coupled Matrix Factorization

Access to complete data in large-scale networks is often infeasible. Therefore, the problem of missing data is a crucial and unavoidable issue in the analysis and modeling of real-world social networks. However, most of the research on different aspects of social networks does not consider this limitation. One effective way to solve this problem is to recover the missing data as a pre-processing step. In this paper, a model is learned from partially observed data to infer unobserved diffusion and structure networks. To jointly discover omitted diffusion activities and hidden network structures, we develop a probabilistic generative model called “DiffStru.” The interrelations among links of nodes and cascade processes are utilized in the proposed method via learning coupled with low-dimensional latent factors. Besides inferring unseen data, latent factors such as community detection may also aid in network classification problems. We tested different missing data scenarios on simulated independent cascades over LFR networks and real datasets, including Twitter and Memetracker. Experiments on these synthetic and real-world datasets show that the proposed method successfully detects invisible social behaviors, predicts links, and identifies latent features.

Graph-Based Motion Artifacts Detection Method from Head Computed Tomography Images.

Computed tomography (CT) images play an important role due to effectiveness and accessibility, however, motion artifacts may obscure or simulate pathology and dramatically degrade the diagnosis accuracy. In recent years, convolutional neural networks (CNNs) have achieved state-of-the-art performance in medical imaging due to the powerful learning ability with the help of the advanced hardware technology. Unfortunately, CNNs have significant overhead on memory usage and computational resources and are labeled ‘black-box’ by scholars for their complex underlying structures. To this end, an interpretable graph-based method has been proposed for motion artifacts detection from head CT images in this paper. From a topological perspective, the artifacts detection problem has been reformulated as a complex network classification problem based on the network topological characteristics of the corresponding complex networks. A motion artifacts detection method based on complex networks (MADM-CN) has been proposed. Firstly, the graph of each CT image is constructed based on the theory of complex networks. Secondly, slice-to-slice relationship has been explored by multiple graph construction. In addition, network topological characteristics are investigated locally and globally, consistent topological characteristics including average degree, average clustering coefficient have been utilized for classification. The experimental results have demonstrated that the proposed MADM-CN has achieved better performance over conventional machine learning and deep learning methods on a real CT dataset, reaching up to 98% of the accuracy and 97% of the sensitivity.

How Do Successful and Failed Projects Differ? A Socio-Technical Analysis

Software development is at the intersection of the social realm , involving people who develop the software, and the technical realm , involving artifacts (code, docs, etc.) that are being produced. It has been shown that a socio-technical perspective provides rich information about the state of a software project. In particular, we are interested in socio-technical factors that are associated with project success . For this purpose, we frame the task as a network classification problem. We show how a set of heterogeneous networks composed of social and technical entities can be jointly embedded in a single vector space enabling mathematically sound comparisons between distinct software projects. Our approach is specifically designed using intuitive metrics stemming from network analysis and statistics to ease the interpretation of results in the context of software engineering wisdom. Based on a selection of 32 open source projects, we perform an empirical study to validate our approach considering three prediction scenarios to test the classification model’s ability generalizing to (1) randomly held-out project snapshots, (2) future project states, and (3) entirely new projects. Our results provide evidence that a socio-technical perspective is superior to a pure social or technical perspective when it comes to early indicators of future project success. To our surprise, the methodology proposed here even shows evidence of being able to generalize to entirely novel (project hold-out set) software projects reaching predication accuracies of 80%, which is a further testament to the efficacy of our approach and beyond what has been possible so far. In addition, we identify key features that are strongly associated with project success. Our results indicate that even relatively simple socio-technical networks capture highly relevant and interpretable information about the early indicators of future project success.

Diametrical Risk Minimization: theory and computations

The theoretical and empirical performance of Empirical Risk Minimization (ERM) often suffers when loss functions are poorly behaved with large Lipschitz moduli and spurious sharp minimizers. We propose and analyze a counterpart to ERM called Diametrical Risk Minimization (DRM), which accounts for worst-case empirical risks within neighborhoods in parameter space. DRM has generalization bounds that are independent of Lipschitz moduli for convex as well as nonconvex problems and it can be implemented using a practical algorithm based on stochastic gradient descent. Numerical results illustrate the ability of DRM to find quality solutions with low generalization error in sharp empirical risk landscapes from benchmark neural network classification problems with corrupted labels.

A novel Chaotic Flower Pollination-based intrusion detection framework

With the rise of network on handheld devices, security of the network has become critical issue. Intrusion detection system is used to predict intrusive packets on network; two-step procedure has been used to predict the intrusion, i.e., feature selection and then classification. Firstly, unwanted and expandable features in data lead to network classification problem which affect the decision capability of the classifiers, so we need optimize feature selection technique. Feature selection technique used in this paper is based on the correlation information known as correlation-based feature selection (CFS). In this paper, CFS’s search algorithm is implemented using Chaotic Flower Pollination Algorithm (CFPA) that logically selects the most favorable features for classification referred as CFPA-CFS. Further, hybridization of CFPA and support vector machine classifier is implemented and named as CFPSVM. Finally, novel IDS framework uses CFPA-CFS and CFPSVM in sequence to predict the intrusion. Further, performance of proposed framework is evaluated using two intrusion detection evaluation datasets, namely KDDCup99 and NSL-KDD. The results demonstrate that proposed CFPA-CFS contributes more critical features for CFPSVM to achieve better accuracy compared with the state-of-the-art methods.

ИСПОЛЬЗОВАНИЕ ГЕНЕТИЧЕСКОГО АЛГОРИТМА ДЛЯ НАСТРОЙКИ ГЛУБОКИХ НЕЙРОННЫХ СЕТЕЙ В ЗАДАЧАХ КЛАССИФИКАЦИИ КОМПЬЮТЕРНЫХ АТАК

The task of multiclass network classification of computer attacks is given. The applicability of deep neural network technology in problem solving has been considered. Deep neural network architecture was chosen based on the strategy of combining a set of convolution and recurrence LSTM layers. Op-timization of neural network parameters based on genetic algorithm is proposed. The presented results of modeling show the possibility of solving the network classification problem in real time.

NETWORK CLASSIFICATION WITH APPLICATIONS TO BRAIN CONNECTOMICS.

While statistical analysis of a single network has received a lot of attention in recent years, with a focus on social networks, analysis of a sample of networks presents its own challenges which require a different set of analytic tools. Here we study the problem of classification of networks with labeled nodes, motivated by applications in neuroimaging. Brain networks are constructed from imaging data to represent functional connectivity between regions of the brain, and previous work has shown the potential of such networks to distinguish between various brain disorders, giving rise to a network classification problem. Existing approaches tend to either treat all edge weights as a long vector, ignoring the network structure, or focus on graph topology as represented by summary measures while ignoring the edge weights. Our goal is to design a classification method that uses both the individual edge information and the network structure of the data in a computationally efficient way, and that can produce a parsimonious and interpretable representation of differences in brain connectivity patterns between classes. We propose a graph classification method that uses edge weights as predictors but incorporates the network nature of the data via penalties that promote sparsity in the number of nodes, in addition to the usual sparsity penalties that encourage selection of edges. We implement the method via efficient convex optimization and provide a detailed analysis of data from two fMRI studies of schizophrenia.

Flower Pollination Algorithm for feature analysis of Kyoto 2006+ data set

Unwanted and large features in data contributes to network classification problem. Features can be selected to improve the performance. In this paper, Flower Pollination Algorithm (FPA) has been proposed to select the optimal features. Further, three predefined feature selection algorithms have been used to selects the most critical attributes for anomaly detection. The performance of FPA and three predefined algorithms have been compared on fifteen features of kyoto 2006+ of Intrusion Detection System (IDS). The evaluation results show that ‘Service (2), Srv_serror_rate (8) and Flag (14) features are the most critical features.

Classification of complex networks based on similarity of topological network features.

Over the past few decades, networks have been widely used to model real-world phenomena. Real-world networks exhibit nontrivial topological characteristics and therefore, many network models are proposed in the literature for generating graphs that are similar to real networks. Network models reproduce nontrivial properties such as long-tail degree distributions or high clustering coefficients. In this context, we encounter the problem of selecting the network model that best fits a given real-world network. The need for a model selection method reveals the network classification problem, in which a target-network is classified into one of the candidate network models. In this paper, we propose a novel network classification method which is independent of the network size and employs an alignment-free metric of network comparison. The proposed method is based on supervised machine learning algorithms and utilizes the topological similarities of networks for the classification task. The experiments show that the proposed method outperforms state-of-the-art methods with respect to classification accuracy, time efficiency, and robustness to noise.