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Co magnetic bilayer films with different stacking structures of fcc/hcp and hcp/fcc were successfully prepared on Al2O3(0001) substrates employing Au and Cu underlayers. The structure and the magnetic properties of these bilayer films were investigated. The crystal structure and the strain of Co layers are influenced by the underlayer. Q-band ferromagnetic resonance analysis has shown that the Co bilayer films consist magnetically of fcc and hcp phases. It has been shown possible to prepare hcp/fcc Co epitaxial magnetic bilayer films that can be used for patterned media applications.

WiFi Peer to Peer (P2P) aka WiFi Direct enables devices to communicate with each other in a peer to peer manner without requiring any Access Point at typical WiFi speed with WPA2 security. With its huge prospect in revolutionizing device to device communication, WiFi P2P can potentially play a much larger role amid the growing interest in M2M communication and Internet of Things. However, unlike a conventional P2P network which operates on mesh topology, WiFi P2P requires one of its group members to act as Group Owner, with whomall the other devices in the group stay associated. The group suffers from a temporary network disruption when the Group Owner suddenly leaves the group without any prior notice. In addition, restoration of the group connectivity consumes much time which is intolerable for most delay sensitive applications. In this paper, we address this issue using our proposed concept of Seamless Group Reformation which helps in maintaining near continuous connectivity and alleviates overdependence of the group on the Group Owner. The concept is seconded by the proposed mechanism of Dormant Backend Links to cut down the total group-disruption time. We implement the mechanism of Dormant Backend Links on a practical WiFi P2P testbed and present an experimental evaluation.

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This paper describes an architecture for deploying virtual IP networks with P2P-like dynamic topology and routing management. Existing virtual IP network deployment mechanisms do not allow for dynamic topology adaptation and fault-tolerance because provisioning of IP tunnels is performed only once-when a virtual network is deployed. We propose a P2P-XBone, in which a P2P protocol such as DHT drives the topology and the routing table of a virtual IP network consistent with its neighbor node state. We describe how to extend both the existing X-Bone system and P2P mechanisms to achieve interworking between them. The P2P-XBone not only provides P2P's characteristics such as self-organization, fault-tolerance and content-based routing to virtual IP networks but also provides higher forwarding performance and simpler implementation to P2P systems due to the support for the use of existing network services. We also show several results on the evaluation of overhead of P2P-driven provisioning and on forwarding performance.