Data generated on Twitter has become a rich source for various data mining tasks. Those data analysis tasks that are dependent on the tweet semantics, such as sentiment analysis, emotion mining, and rumor detection among others, suffer considerably if the tweet is not credible, not real, or spam. In this paper, we perform an extensive analysis on credibility of Arabic content on Twitter. We also build a classification model (CAT) to automatically predict the credibility of a given Arabic tweet. Of particular originality is the inclusion of features extracted directly or indirectly from the author's profile and timeline. To train and test CAT, we annotated for credibility a data set of 9, 000 Arabic tweets that are topic independent. CAT achieved consistent improvements in predicting the credibility of the tweets when compared to several baselines and when compared to the state-of-the-art approach with an improvement of 21% in weighted average Fmeasure. We also conducted experiments to highlight the importance of the userbased features as opposed to the contentbased features. We conclude our work with a feature reduction experiment that highlights the best indicative features of credibility.

DR-BIP is an extension of the BIP component framework intended for programming reconfigurable systems encompassing various aspects of dynamism. It relies on architectural motifs to structure the architecture of a system and to coordinate its reconfiguration at runtime. An architectural motif defines a set of interacting components that evolve according to reconfiguration rules. With DR-BIP, the dynamism can be captured as the interplay of dynamic changes in three independent directions 1) the organization of interactions between instances of components in a given configuration; 2) the reconfiguration mechanisms allowing creation/deletion of components and management of their interaction according to a given architectural motif; 3) the migration of components between predefined architectural motifs which characterizes dynamic execution environments. The paper lays down the formal foundation of DR-BIP, illustrates its expressiveness on few examples and discusses avenues for dynamic reconfigurable system design.

DR-BIP is an extension of the BIP component framework intended for programming reconfigurable systems encompassing various aspects of dynamism. A system is built from instances of types of components characterized by their interfaces. The latter consist of sets of ports through which data can be exchanged when interactions take place. DR-BIP allows the description of parametric exogenous interactions and reconfiguration operations. To naturally model self-organization and mobility of components, a system is composed of several architecture motifs, each motif consisting of a set of component instances and coordination rules. The use of motifs allows a disciplined management of dynamically changing coordination rules. The paper illustrates the basic concepts of DR-BIP through a collection of four non-trivial exercises from different application areas: fault-tolerant systems, mobile systems and autonomous systems. The presented solutions show that DR-BIP is both minimal and expressive allowing concise and natural description of nontrivial systems.

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