205 research outputs found
A Survey on Handover Management in Mobility Architectures
This work presents a comprehensive and structured taxonomy of available
techniques for managing the handover process in mobility architectures.
Representative works from the existing literature have been divided into
appropriate categories, based on their ability to support horizontal handovers,
vertical handovers and multihoming. We describe approaches designed to work on
the current Internet (i.e. IPv4-based networks), as well as those that have
been devised for the "future" Internet (e.g. IPv6-based networks and
extensions). Quantitative measures and qualitative indicators are also
presented and used to evaluate and compare the examined approaches. This
critical review provides some valuable guidelines and suggestions for designing
and developing mobility architectures, including some practical expedients
(e.g. those required in the current Internet environment), aimed to cope with
the presence of NAT/firewalls and to provide support to legacy systems and
several communication protocols working at the application layer
Mobile Computing in Digital Ecosystems: Design Issues and Challenges
In this paper we argue that the set of wireless, mobile devices (e.g.,
portable telephones, tablet PCs, GPS navigators, media players) commonly used
by human users enables the construction of what we term a digital ecosystem,
i.e., an ecosystem constructed out of so-called digital organisms (see below),
that can foster the development of novel distributed services. In this context,
a human user equipped with his/her own mobile devices, can be though of as a
digital organism (DO), a subsystem characterized by a set of peculiar features
and resources it can offer to the rest of the ecosystem for use from its peer
DOs. The internal organization of the DO must address issues of management of
its own resources, including power consumption. Inside the DO and among DOs,
peer-to-peer interaction mechanisms can be conveniently deployed to favor
resource sharing and data dissemination. Throughout this paper, we show that
most of the solutions and technologies needed to construct a digital ecosystem
are already available. What is still missing is a framework (i.e., mechanisms,
protocols, services) that can support effectively the integration and
cooperation of these technologies. In addition, in the following we show that
that framework can be implemented as a middleware subsystem that enables novel
and ubiquitous forms of computation and communication. Finally, in order to
illustrate the effectiveness of our approach, we introduce some experimental
results we have obtained from preliminary implementations of (parts of) that
subsystem.Comment: Proceedings of the 7th International wireless Communications and
Mobile Computing conference (IWCMC-2011), Emergency Management: Communication
and Computing Platforms Worksho
Network Localization by Shadow Edges
Localization is a fundamental task for sensor networks. Traditional network
construction approaches allow to obtain localized networks requiring the nodes
to be at least tri-connected (in 2D), i.e., the communication graph needs to be
globally rigid. In this paper we exploit, besides the information on the
neighbors sensed by each robot/sensor, also the information about the lack of
communication among nodes. The result is a framework where the nodes are
required to be bi-connected and the communication graph has to be rigid. This
is possible considering a novel typology of link, namely Shadow Edges, that
account for the lack of communication among nodes and allow to reduce the
uncertainty associated to the position of the nodes.Comment: preprint submitted to 2013 European Control Conference, July 17-19
2013, Zurich, Switzerlan
Resilience in Critical Infrastructures: The Role of Modelling and Simulation
Resilience and risk are fundamental concepts for critical infrastructure protection, but it is complex to assess them. Modelling critical infrastructure interdependency helps in evaluating the resilience and risk metrics. We propose the MHR approach as a road-map to model infrastructures and it is implemented using CISIApro 2.0. MHR suggests considering three different layers in each infrastructure: holistic, service and reductionist agents. In this chapter, this framework has been tested in a scenario made of a modern telecommunication network, a hospital ward and a smart factory. The scenario takes into account cyber attacks and their consequences on the components, services and holistic nodes. The proposed framework is under validation within the EU H2020 RESISTO project with good results and in various test-beds
Reconstruction of Riser Profiles by an Underwater Robot Using Inertial Navigation
This paper proposes a kinematic model and an inertial localization system architecture
for a riser inspecting robot. The robot scrolls outside the catenary riser, used for underwater
petroleum exploration, and is designed to perform several nondestructive tests. It
can also be used to reconstruct the riser profile. Here, a realistic simulation model of robot
kinematics and its environment is proposed, using different sources of data: oil platform
characteristics, riser static configuration, sea currents and waves, vortex-induced vibrations,
and instrumentation model. A dynamic finite element model of the riser generates
a nominal riser profile. When the robot kinematic model virtually scrolls the simulated
riser profile, a robot kinematic pattern is calculated. This pattern feeds error models of a
strapdown inertial measurement unit (IMU) and of a depth sensor. A Kalman filter fuses
the simulated accelerometers data with simulated external measurements. Along the riser
vertical part, the estimated localization error between the simulated nominal and Kalman
filter reconstructed robot paths was about 2 m. When the robot model approaches the
seabed it assumes a more horizontal trajectory and the localization error increases significantly
Model Predictive Control for Building Active Demand Response Systems
The Active Demand Response (ADR), integrated with the distributed energy generation and storage systems, is the most common strategy for the optimization of energy consumption and indoor comfort in buildings, considering the energy availability and the balancing of the energy production from renewable sources. In the paper an overview of basic requirements and applications of ADR management is presented. Specifically, the model predictive control (MPC) adopted in several applications as optimal control strategy in the ADR buildings context is analysed. Finally the research experience of the authors in this context is described
Multiplicities of charged pions and unidentified charged hadrons from deep-inelastic scattering of muons off an isoscalar target
Multiplicities of charged pions and unidentified hadrons produced in
deep-inelastic scattering were measured in bins of the Bjorken scaling variable
, the relative virtual-photon energy and the relative hadron energy .
Data were obtained by the COMPASS Collaboration using a 160 GeV muon beam and
an isoscalar target (LiD). They cover the kinematic domain in the photon
virtuality > 1(GeV/c, , and . In addition, a leading-order pQCD analysis was performed using the
pion multiplicity results to extract quark fragmentation functions
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