Distributed software built from components has become a mainstay of service-oriented applications, which frequently undergo reconfigurations to adapt to changes in their operating environment or their functional requirements. Given the complexity of distributed software and the adverse effects of incorrect reconfigurations, a suitable methodology is needed to ensure the correctness of reconfigurations in component-based systems. This survey gives the reader a global perspective over existing formal techniques that pursue this goal. It distinguishes different ways in which formal methods can improve the reliability of reconfigurations, and lists techniques that contribute to solving each of these particular scientific challenges.

For over a decade, MapReduce has become a prominent programming model to handle vast amounts of raw data in large scale systems. This model ensures scalability, reliability and availability aspects with reasonable query processing time. However these large scale systems still face some challenges: data skew, task imbalance, high disk I/O and redistribution costs can have disastrous effects on performance.In this paper, we introduce MRFA-Join algorithm: a new frequency adaptive algorithm based on MapReduce programming model and a randomised key redistribution approach for join processing of large-scale datasets. A cost analysis of this algorithm shows that our approach is insensitive to data skew and ensures perfect balancing properties during all stages of join computation. These performances have been confirmed by a series of experimentations

Internet of Things (IoT) applications are becoming increasingly critical and require rigorous formal verification. In this paper we target Contiki, a widely used open-source OS for IoT, and present a verification case study of one of its most critical modules: that of linked lists. Its API and list representation differ from the classical linked list implementations, and are particularly challenging for deductive verification. The proposed verification technique relies on a parallel view of a list through a companion ghost array. This approach makes it possible to perform most proofs automatically using the Frama-C/WP tool, only a small number of auxiliary lemmas being proved interactively in the Coq proof assistant. We present an elegant segment-based reasoning over the companion array developed for the proof. Finally, we validate the proposed specification by proving a few functions manipulating lists.