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In recent years, research on location predictions by mining trajectories of users has attracted a lot of attentions. Existing studies on this topic mostly focus on individual movements, considering the trajectories as solo movements. However, a user usually does not visit locations just for the personal interest. The preference of a travel group has significant impacts on the places they have visited. In this paper, we propose a novel personalized location prediction approach which further takes into account users' travel group type. To achieve this goal, we propose a new group pattern discovery approach to extract the travel groups from spatial-temporal trajectories of users. Type of the discovered groups, then, are identified through utilizing the profile information of the group members. The core idea underlying our proposal is the discovery of significant movement patterns of users to capture frequent movements by considering the group types. Finally, the problem of location prediction is formulated as an estimation of the probability of a given user visiting a given location based on his/her current movement and his/her group type. To the best of our knowledge, this is the first work on location prediction based on trajectory pattern mining that investigates the influence of travel group type. By means of a comprehensive evaluation using various datasets, we show that our proposed location prediction framework achieves significantly higher performance than previous location prediction methods.

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With the development of new networking paradigms and wireless protocols, nodes with different capabilities are used to form a heterogeneous network. The performance of this kind of networks is seriously deteriorated because of the bottlenecks inside the network. In addition, because of the application requirements, different routing schemes are required toward one particular application. This needs a tool to design protocols to avoid the bottlenecked nodes and adaptable to application requirement. Polychromatic sets theory has the ability to do so. This paper demonstrates the applications of polychromatic sets theory in route discovery and protocols design for heterogeneous networks. From extensive simulations, it shows the nodes with high priority are selected for routing, which greatly increases the performance of the network. This demonstrates that a new type of graph theory could be applied to solve problems of complex networks.

Software defect prediction (SDP) is used to perform the statistical analysis of historical defect data to find out the distribution rule of historical defects, so as to effectively predict defects in the new software. However, there are redundant and irrelevant features in the software defect datasets affecting the performance of defect predictors. In order to identify and remove the redundant and irrelevant features in software defect datasets, we propose ReliefF-based clustering (RFC), a clusterbased feature selection algorithm. Then, the correlation between features is calculated based on the symmetric uncertainty. According to the correlation degree, RFC partitions features into k clusters based on the k-medoids algorithm, and finally selects the representative features from each cluster to form the final feature subset. In the experiments, we compare the proposed RFC with classical feature selection algorithms on nine National Aeronautics and Space Administration (NASA) software defect prediction datasets in terms of area under curve (AUC) and Fvalue. The experimental results show that RFC can effectively improve the performance of SDP.