Tilted rotors in multirotor vehicles have shown to be useful for different practical reasons. For instance, increasing yaw maneuverability or enabling full position and attitude control of hexarotor vehicles. It has also been proven that a hexagon-shaped multirotor is capable of complete attitude and altitude control under failures of one of its rotors. However, when a rotor fails, the torque that can be reached in the worst- case direction decreases considerably.This work proposes to actively change the tilt angle of the rotors when a failure occurs. This rotor reconfiguration increases the maximum torque that can be achieved in the most stressful direction, reducing maneuverability limitations. Experimental validations are shown, where the proposed reconfigurable tilted rotor is used in order to control a hexarotor vehicle when a failure appears mid-flight. The impact of the delay in the reconfiguration when a failure occurs is also addressed.

Software defined networking (SDN) and Network Function Virtualization (NFV) are new approaches to next generation network architecture for operator networks that have received much discussion in the research literature and in new forums organized to standardize their interfaces. While these approaches to network architecture are important, they only cover part of the problem. A fundamental property required from any next generation architecture is support for rapid, cross-domain service innovation. In this paper, we discuss Service Provider SDN (SP-SDN), an architectural approach to rapid service innovation based on exposure of functionality for cross-domain control at the service layer. The functionality is exposed through Web-style interfaces that feature abstractions crafted by suppressing detail irrelevant for the majority of the created services. The control spans mobile, fixed and cloud operator networks, allowing the rapid and flexible provisioning of services across all three domains. We compare this approach to SDN and NFV, and find that SP-SDN complements rather than competes with the two. We present two examples of prototype systems built with SP-SDN.

The tasks of entrapping/escorting and patrolling around an autonomous target are presented making use of the multi-robot cluster space control approach. The cluster space control technique promotes simplified specification and monitoring of the motion of mobile multi-robot systems of limited size. Previous work has established the conceptual foundation of this approach and has experimentally verified and validated its use for 2-robot, 3-robot and 4-robot systems, with varying implementations ranging from automated trajectory control to human-in-the-loop piloting. In this publication, we show that the problem of entrapping/escorting/patrolling is trivial to define and manage from a cluster space perspective. Using a 3-robot experimental testbed, results are shown for the given tasks. We also revise the definition of the cluster space framework for a three-robot formation and incorporate a robot-level obstacle avoidance functionality.

The cluster space control technique promotes simplified specification and monitoring of the motion of mobile multi-robot systems of limited size. Previous work has established the conceptual foundation of this approach and has experimentally verified and validated its use for two diverse 2- robot systems and with varying implementations ranging from automated trajectory control to human-in-the-loop piloting. In this paper, we present the cluster space control of a 3-robot system. In doing so, we develop the fundamental kinematic relationships, illustrate the closed-loop control framework, describe the simulation and hardware testbed environments used for verification, and present initial experimental results of the successfully implemented system.

The session initiation protocol (SIP) is an application-layer protocol to establish and manage sessions. SIP provides user mobility by having user agents register their location with a server in the network. The host identity protocol (HIP) is a shim layer between the network and the transport layers to establish and manage secure connections between hosts which may be mobile. In this paper, we propose a framework to combine SIP and HIP, and discuss the advantages of doing so. The advantages this framework provides relate to security, mobility, and multihoming. Additionally, we discuss how a P2P SIP (peer- to-peer SIP) system can be implemented on top of a HIP-based overlay network and the characteristics of such a system. We also offer some insights into an experimental prototype implemented as a proof-of-concept of the SIP-HIP interaction.