Specific Feature Space Research Articles

Graph Representation Learning With Adaptive Metric

Contrastive learning has been widely used in graph representation learning, which extracts node or graph representations by contrasting positive and negative node pairs. It requires node representations (embeddings) to reflect their correlations in topology, increasing the similarities between an anchor node and its positive nodes, or reducing the similarities with its negative nodes in embedding space. However, most existing contrastive models measure similarities through a fixed metric that equally scores all sample pairs in a specific feature space, but ignores the varieties of node attributes and network topologies. Moreover, these fixed metrics are always defined explicitly and manually, which makes them unsuitable for applying to all graphs and networks. To solve these problems, we propose a novel graph representation learning model with an adaptive metric, called GRAM, which produces appropriate similarity scores of node pairs according to the different significance of each dimension in their embedding vectors and adaptive metrics based on data distribution. With these scores, it is better to train a graph encoder and obtain representative embeddings. Experimental results show that GRAM has strong competitiveness in multiple tasks.

RnRTD: Intelligent Approach Based on the Relationship-Driven Neural Network and Restricted Tensor Decomposition for Multiple Accusation Judgment in Legal Cases.

The use of intelligent judgment technology to assist in judgment is an inevitable trend in the development of judgment in contemporary social legal cases. Using big data and artificial intelligence technology to accurately determine multiple accusations involved in legal cases is an urgent problem to be solved in legal judgment. The key to solving these problems lies in two points, namely, (1) characterization of legal cases and (2) classification and prediction of legal case data. Traditional methods of entity characterization rely on feature extraction, which is often based on vocabulary and syntax information. Thus, traditional entity characterization often requires extensive energy and has poor generality, thus introducing a large amount of computation and limitation to subsequent classification algorithms. This study proposes an intelligent judgment approach called RnRTD, which is based on the relationship-driven recurrent neural network (rdRNN) and restricted tensor decomposition (RTD). We represent legal cases as tensors and propose an innovative RTD method. RTD has low dependence on vocabulary and syntax and extracts the feature structure that is most favorable for improving the accuracy of the subsequent classification algorithm. RTD maps the tensors, which represent legal cases, into a specific feature space and transforms the original tensor into a core tensor and its corresponding factor matrices. This study uses rdRNN to continuously update and optimize the constraints in RTD so that rdRNN can have the best legal case classification effect in the target feature space generated by RTD. Simultaneously, rdRNN sets up a new gate and a similar case list to represent the interaction between legal cases. In comparison with traditional feature extraction methods, our proposed RTD method is less expensive and more universal in the characterization of legal cases. Moreover, rdRNN with an RTD layer has a better effect than the recurrent neural network (RNN) only on the classification and prediction of multiple accusations in legal cases. Experiments show that compared with previous approaches, our method achieves higher accuracy in the classification and prediction of multiple accusations in legal cases, and our algorithm is more interpretable.

Hyper-Clique Graph Matching and Applications

This paper proposes a method for hyper-clique graph (HCG) generation, which can be considered an extension of classical graphs and hyper-graphs in which the node is replaced with the clique (a set of neighboring nodes in a specific feature space) and the hyper-edge linking multiple nodes is replaced with the hyper-edge linking multiple cliques. In addition, we propose the HCG matching method by preserving global and local structures. Specifically, we embed the clique relations of arbitrary orders in a high-order similarity tensor in a recursive manner. Then, we formulate the objective function of HCG matching with respect to two latent variables: the latent clique structure information in the original graph and the similarity measure of clique sets from pairwise HCGs. Since the objective function is not jointly convex with respect to both latent variables, we decompose it into two consecutive measurements for optimization: 1) a clique-to-clique similarity measurement by preserving local unary and pairwise correspondences and 2) a graph-to-graph similarity measurement by preserving global clique-to-clique correspondence. We suitably adopt the affinity-preserving reweighted random walks to optimize the objective function. We extensively evaluate the HCG matching performance on multiple applications: 1) we evaluate the robustness of HCG with respect to the deformation noise, the number of outliers, and the edge density on synthetic data and explore the effects of both the clique order and hyper-edge order on performance; 2) we explore HCG matching for feature point matching on multiple image data sets (CMU house sequence, Caltech+MSRC, and Car+Motor); and 3) we explore HCG matching for multi-view object retrieval, which is a much more challenging task since multi-view objects contain significant variations of illumination, viewpoint, and so on, using popular data sets (MV-RED and NTU). A comparison against the state-of-the-art methods demonstrates the superior performance of the proposed method.

Identifying the semantic orientation of terms using S-HAL for sentiment analysis

Sentiment analysis continues to be a most important research problem due to its abundant applications. Identifying the semantic orientation of subjective terms (words or phrases) is a fundamental task for sentiment analysis. In this paper, we propose a new method for identifying the semantic orientation of subjective terms to perform sentiment analysis. The method takes a classification approach that is based on a novel semantic orientation representation model called S-HAL (Sentiment Hyperspace Analogue to Language). S-HAL basically produces a set of weighted features based on surrounding words, and characterizes the semantic orientation information of words via a specific feature space. Because the method incorporates the idea underlying HAL and the hypothesis verified by the method of semantic orientation inference from pointwise mutual information (SO-PMI), it can quickly and accurately identify the semantic orientation of terms without the use of an Internet search engine. The results of an empirical evaluation show that our method outperforms other known methods.

Audio steganalysis with Hausdorff distance higher order statistics using a rule based decision tree paradigm

The aim of this paper is to construct a practical forensic steganalysis tool for audio signals that can properly analyze the statistics disturbed by stego embedding and classify them to selected current steganographic methods. The objective of this paper is to prove that the choice of effective stego sensitive features and a proficient machine learning paradigm enhances the detection accuracy of the steganalyser. In this paper a rule based approach with a family of six decision tree classifiers viz., Alternating Decision Tree, Decision Stump, J48, Logical Model Tree, Naïve Baye’s Tree and Fast Decision Tree learner, to perform the detection of audio subliminal channel is introduced. In particular the higher order statistics extracted from the Hausdorff distance are investigated for an improvement of the detection performance, as competent audio steganalytic features. The evaluation of the enhanced feature space and the decision tree paradigm, on a database containing 4800 clean and stego audio files is performed for classical steganographic as well as for watermarking algorithms. With this strategy it is shown how general forensic approach can detect information hiding techniques in the field of covert communication as well as for DRM applications. For the latter case, the detection of the presence of a potential watermark in a specific feature space can lead to new attacks or to a better design of the watermarking pattern.