Summary The messages in microblogs, like Twitter, present a wealth of information around the hot topics and public opinions. Topic detection and tracking enables a better understanding of the incoming information from social networks. Many of the studies performed in this field consider a set of predefined number of topics (clusters) which remain constant during the detection process. Such approaches are not efficient when data is dynamic and cumulative. In addition, nonparametric evolutionary topic models do not have an accurate performance on short texts due to the data deficiency. In this article, we propose an evolutionary clustering model based on the Bayesian nonparametric Dirichlet process mixture model, which automatically determines the number of clusters. To improve the algorithm performance when dealing with short social media texts, temporal information of tweets and other social network parameters are used in a weighted combination to augment the text similarity in detecting topics. Model evaluation is performed on the data gathered from the Twitter during a 2.5‐month period. Results reveal that the social network information can promote the topic detection performance. The proposed model outperforms previous study in terms of topic coherence and clustering performance, leading to a better clustering on short texts.

In many popular applications like peer-to-peer systems, large amounts of data are distributed among multiple sources. Analysis of this data and identifying clusters is challenging due to processing, storage, and transmission costs. In this paper, we propose GDCluster, a general fully decentralized clustering method, which is capable of clustering dynamic and distributed data sets. Nodes continuously cooperate through decentralized gossip-based communication to maintain summarized views of the data set. We customize GDCluster for execution of the partition-based and density-based clustering methods on the summarized views, and also offer enhancements to the basic algorithm. Coping with dynamic data is made possible by gradually adapting the clustering model. Our experimental evaluations show that GDCluster can discover the clusters efficiently with scalable transmission cost, and also expose its supremacy in comparison to the popular method LSP2P.

It has become essential to scrutinize and evaluate software development methodologies, mainly because of their increasing number and variety. Evaluation is required to gain a better understanding of the features, strengths, and weaknesses of the methodologies. The results of such evaluations can be leveraged to identify the methodology most appropriate for a specific context. Moreover, methodology improvement and evolution can be accelerated using these results. However, despite extensive research, there is still a need for a feature/criterion set that is general enough to allow methodologies to be evaluated regardless of their types. We propose a general evaluation framework which addresses this requirement. In order to improve the applicability of the proposed framework, all the features - general and specific - are arranged in a hierarchy along with their corresponding criteria. Providing different levels of abstraction enables users to choose the suitable criteria based on the context. Major evaluation frameworks for object-oriented, agent-oriented, and aspect-oriented methodologies have been studied and assessed against the proposed framework to demonstrate its reliability and validity.