MANETs are widely used to communicate with each other wireless devices via bidirectional wireless links either directly or indirectly and these functionalities are performed by collection of mobile nodes equipped with both wireless transmitter and a receiver. However, the open medium and wide distribution of nodes make MANET vulnerable to malicious attackers. In this case, it is crucial to develop efficient intrusion-detection mechanisms to protect MANET from attacks. To overcome this problem a new approach for intrusion-detection system named Enhanced Adaptive Acknowledgment (EAACK) is proposed for MANETs. Compared to contemporary approaches, EAACK demonstrates higher malicious-behavior-detection rates in certain circumstances while does not greatly affect the network performances.
MANETs have unique characteristics like dynamic topology, wireless radio medium, limited resources and lack of centralized administration, as a result, they are vulnerable to different types of attacks in different layers of protocol stack. Each node in a MANET is capable of acting as a router. Routing is one of the aspects having various security concerns. In this paper, we will present survey of common Denial-of-Service (DoS) attacks on network layer namely Wormhole attack, Black hole attack and Gray hole attack which are serious threats for MANETs. We will also discuss some proposed solutions to detect and prevent these attacks. As MANETs are widely used in many vital applications, lots of research work has to be done to find efficient solutions against these DoS attacks that can work for different routing protocols.
Purpose ::: The aim of this study was to determine whether high keV monoenergetic reconstruction of dual energy computed tomography (DECT) could be used to overcome the effects of beam hardening artefact that arise from preferential deflection of low energy photons.