West Nile virus meningoencephalitis during pregnancy: Case report with MR imaging findings

AbstractMR imaging findings of West Nile virus meningoencephalitis during pregnancy are unknown. We report the first case of serologically proved West Nile virus meningoencephalitis complicating pregnancy with MRI findings. MR imaging of the brain revealed abnormal hyperintensity in the periventricular white matter near the left frontal horn and insular left lobe on fluid-attenuated inversion recovery and T2-weighted images. Evolution was favorable, and no obvious fetal consequences of infection were noted after birth. Recognition of the MR imaging appearance of this entity is important because of the expanding epidemic

LNT: A logical neighbor tree secure group communication scheme for wireless sensor networks

Secure group communication is a paradigm that primarily designates one-to-many communication security. The proposed works relevant to secure group communication have predominantly considered the whole network as being a single group managed by a central powerful node capable of supporting heavy communication, computation and storage cost. However, a typical Wireless Sensor Network (WSN) may contain several groups, and each one is maintained by a sensor node (the group controller) with constrained resources. Moreover, the previously proposed schemes require a multicast routing support to deliver the rekeying messages. Nevertheless, multicast routing can incur heavy storage and communication overheads in the case of a wireless sensor network. Due to these two major limitations, we have reckoned it necessary to propose a new secure group communication with a lightweight rekeying process. Our proposal overcomes the two limitations mentioned above, and can be applied to a homogeneous WSN with resource-constrained nodes with no need for a multicast routing support. Actually, the analysis and simulation results have clearly demonstrated that our scheme outperforms the previous well-known solutions

LNT: a Logical Neighbor Tree for Secure Group Management in Wireless Sensor Networks

Secure group management is an important issue in Wireless Sensor Networks (WSNs). The most of previous works consider the whole network as a single group managed by a central, powerful node (e.g., the base station) capable of supporting heavy communication, computation and storage cost. However, typical WSNs applications may benefit from being designed and implemented as a collection of multiple logical groups, each one is maintained by a sensor node (the group controller) with constrained resources. Furthermore, previous schemes require multicast support at the routing level to deliver rekeying messages. Unfortunately, multicast may cause a storage and communication overhead that are not a_ordable in a WSN. In order to go beyond these two limitations, we propose a new secure group management scheme with a lightweight re-keying process. The scheme allows multiple logical groups, each one is maintained and rekeyed separately by a resource-constrained sensor node without requiring multicast routing support. We prove that the scheme is secure and we evaluate its performance from several view points. Actually, we show that our scheme outperforms some previous well-known schemes such as LKH

Probabilistic Bandwidth Assignment in Wireless Sensor Networks

Abstract. With this paper we offer an insight in designing and analyzing wireless sensor networks in a versatile manner. Our framework applies probabilistic and component-based design principles for the wireless sensor network modeling and consequently analysis; while maintaining flexibility and accuracy. In particular, we address the problem of allocating and reconfiguring the available bandwidth. The framework has been successfully implemented in IEEE 802.15.4 using an Admission Control Manager (ACM); which is a module of the MAC layer that guarantees that the nodes respect their probabilistic bandwidth assignment as well as the bandwidth assignment policy applied. The proposed framework also aims to accurately analyze the behaviors of communication protocols for energy-consumption and reliability purposes. We evaluate the probabilistic bandwidth assignment methods using CSMA/CA access protocol of IEEE 802.15.4. Furthermore, we analyze the behavior of the ACM and compare the performance of the network with and without using the ACM against the original standard. The simulation results show that the use of ACM increases the overall performance of the network. 4