Belief Peaks Clustering (BPC) algorithm is a new variant of Density Peaks Clustering (DPC) algorithm based on fuzzy perspective. It uses fuzzy mathematics to describe the distribution characteristics and correlation of data. However, BPC algorithm mainly relies on the information of local data points in the calculation of belief values, instead of investigating the distribution and structure of the whole dataset. Moreover, the robustness of the original allocation strategy is weak. To solve these problems, a fuzzy Clustering algorithm based on Belief Subcluster Cutting (BSCC) was proposed by combining belief peaks and spectral method. Firstly, the dataset was divided into many high-purity subclusters by local belief information. Then, the subcluster was regarded as a new sample, and the spectral method was used for cutting graph clustering through the similarity relationship between clusters, thus coupling local information and global information. Finally, the points in the subcluster were assigned to the class cluster where the subcluster was located to complete the final clustering. Compared with BPC algorithm, BSCC has obvious advantages on datasets with multiple subclusters, and it has the ACCuracy (ACC) improvement of 16.38 and 21.35 percentage points on americanflag dataset and Car dataset, respectively. Clustering experimental results on synthetic datasets and real datasets show that BSCC outperforms BPC and the other seven clustering algorithms on the three evaluation indicators of Adjusted Rand Index (ARI), Normalized Mutual Information (NMI) and ACC.
Aiming at the problems that the degree of support is not a good indicator for the interestingness of sequential patterns and the quality of reported sequential patterns is not evaluated in traditional sequential patterns mining algorithms, a statistically significant sequential patterns mining algorithm under influence degree, calling ISSPM (Influence-based Significant Sequential Patterns Mining), was proposed. Firstly, all sequential patterns meeting the interestingness constraint were mined recursively. Then, the itemset permuting method was introduced to construct permutation test null distribution for these sequential patterns. Finally, the statistical measures of the evaluated sequential patterns were calculated from this distribution, and all statistically significant sequential patterns were found from the above sequential patterns. In the experiments with the PSPM (Prefix-projected Sequential Patterns Mining), SPDL (Sequential Patterns Discovering under Leverage) and PSDSP (Permutation Strategies for Discovering Sequential Patterns) algorithms on the real-world sequential record datasets, ISSPM algorithm reports fewer but more interesting sequential patterns. Experimental results on the synthetic sequential record datasets show that the average proportion of the false positive sequential patterns reported by the ISSPM algorithm is 3.39%, and the discovery rate of embedded patterns of this algorithm is not less than 66.7%, which are significantly better than those of the above three algorithms to compare. It can be seen that the statistically significant sequential patterns reported by ISSPM algorithm can reflect more valuable information in sequential record datasets, and the decisions made based on the information are more reliable.
When mining news features and user features, the existing news recommendation models often lack comprehensiveness since they often fail to consider the relationship between the browsed news, the change of time series, and the importance of different news to users. At the same time, the existing models also have shortcomings in more fine-grained content feature mining. Therefore, a news recommendation model with deep feature fusion injecting attention mechanism was constructed, which can comprehensively and non-redundantly conduct user characterization and extract the features of more fine-grained news fragments. Firstly, a deep learning-based method was used to deeply extract the feature matrix of news text through the Convolutional Neural Network (CNN) injecting attention mechanism. By adding time series prediction to the news that users had browsed and injecting multi-head self-attention mechanism, the interest characteristics of users were extracted. Finally, a real Chinese dataset and English dataset were used to carry out experiments with convergence time, Mean Reciprocal Rank (MRR) and normalized Discounted Cumulative Gain (nDCG) as indicators. Compared with Neural news Recommendation with Multi-head Self-attention (NRMS) and other models, on the Chinese dataset, the proposed model has the average improvement rate of nDCG from -0.22% to 4.91% and MRR from -0.82% to 3.48%. Compared with the only model with negative improvement rate, the proposed model has the convergence time reduced by 7.63%. on the English dataset, the proposed model has the improvement rates reached 0.07% to 1.75% and 0.03% to 1.30% respectively on nDCG and MRR; At the same time this model always has fast convergence speed. Results of ablation experiments show that adding attention mechanism and time series prediction module is effective.
Fake news not only leads to misconceptions and damages people's right to know the truth, but also reduces the credibility of news websites. In view of the occurrence of fake news in news websites, a fake news detection method based on blockchain technology was proposed. Firstly, the smart contract was invoked to randomly assign reviewers for the news for determining the authenticity of the news. Then, the credibility of the review results was improved by adjusting the number of reviewers and ensuring the number of effective reviewers. At the same time, the incentive mechanism was designed with rewards distributed according to the reviewers' behaviors, and the reviewers' behaviors and rewards were analyzed by game theory. In order to gain the maximum benefit, the reviewers' behaviors should be honest. An auditing mechanism was designed to detect malicious reviewers to improve system security. Finally, a simple blockchain fake news detection system was implemented by using Ethereum smart contract and simulated for fake news detection, and the results show that the accuracy of news authenticity detection of the proposed method reaches 95%, indicating that the proposed method can effectively prevent the release of fake news.
A fast and effective quality assessment algorithm of no-reference blurred image based on improving the classic Repeat blur (Reblur) processing algorithm was proposed for the high computational cost in traditional methods. The proposed algorithm took into account the human visual system, selected the image blocks that human was interested in instead of the entire image using the local variance, constructed blurred image blocks through low-pass filter, calculated the difference of the adjacent pixels between the original and the blurred image blocks to obtain the original image objective quality evaluation parameters. The simulation results show that compared to the traditional method, the proposed algorithm is more consistent with the subjective evaluation results with the Pearson correlation coefficient increasing 0.01 and less complex with half running time.