The sensor nodes in wireless sensor networks may be deployed in unattended and possibly hostile environments. The ill-disposed environment affects the monitoring infrastructure that includes the sensor nodes and the network. In addition, node failures and environmental hazards cause frequent topology changes, communication failures, and network partitioning. This in turn adds a new dimension to the fragility of the network topology. Such perturbations are far more common than those found in conventional wireless networks thus, demand efficient techniques for discovering disruptive behavior in such networks. Traditional fault diagnosis techniques devised for multiprocessor systems are not directly applicable to wireless sensor networks due to their specific requirements and limitations. This survey integrates research efforts that have been produced in fault diagnosis specifically for wireless sensor networks. The survey aims at clarifying and uncovering the potential of this technology by providing the technique-based taxonomy. The fault diagnosis techniques are classified based on the nature of the tests, correlation between sensor readings and characteristics of sensor nodes and the network.

Vehicular communication is an important and emerging area of research in the field of vehicular technology. The development of software and hardware in communication systems leads to the generation of new networks. Many researches and projects have been conducted in this upcoming area. Many government projects have been implemented in the USA, Japan and the European Union. The main objective of using this new technology is to create an accident free environment. New architectures, protocols and implementations of vehicular ad‐hoc network (VANET) have been made in recent years to provide Intelligent Transportation Services. In this study, the authors survey the current issues like development, deployment, security challenges and about the current projects running in different countries. They also survey the mobility models and simulators required to implement VANET. They have also reviewed the emerging applications of VANET which provides services to the end users. At last, they have presented future research problems in VANET. The main motive of this survey is to explore the current ideas in vehicular communication.