288 research outputs found
A one hop overlay system for Mobile Ad Hoc Networks
Peer-to-Peer (P2P) overlays were initially proposed for use with wired networks.
However, the very rapid proliferation of wireless communication technology has
prompted a need for adoption of P2P systems in mobile networks too. There are
many common characteristics between P2P overlay networks and Mobile Ad-hoc
Networks (MANET). Self-organization, decentralization, a dynamic nature and
changing topology are the most commonly shared features. Furthermore, when
used together, the two approaches complement each other. P2P overlays provide
data storage/retrieval functionality and MANET provides wireless connectivity
between clients without depending on any pre-existing infrastructure. P2P overlay
networks can be deployed over MANET to address content discovery issues.
However, previous research has shown that deploying P2P systems straight over
MANET does not exhibit satisfactory performance. Bandwidth limitation, limited
resources and node mobility are some of the key constraints.
This thesis proposes a novel approach, OneHopOverlay4MANET, to exploit the
synergies between MANET and P2P overlays through cross-layering. It combines
Distributed Hash Table (DHT) based structured P2P overlays with MANET underlay
routing protocols to achieve one logical hop between any pair of overlay
nodes. OneHopOverlay4MANET constructs a cross-layer channel to permit direct
exchange of routing information between the Application layer, where the overlay
operates, and the MANET underlay layer. Consequently, underlay routing information
can be shared and used by the overlay. Thus, OneHopOverlay4MANET
reduces the typical management traffic when deploying traditional P2P systems
over MANET. Moreover, as a result of building one hop overlay, OneHopOverlay4MANET
can eliminate the mismatching issue between overlay and underlay
and hence resolve key lookups in a short time, enhancing the performance of the
overlay.
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In this thesis, we present OneHopOverlay4MANET and evaluate its performance
when combined with different underlay routing protocols. OneHopOverlay4MANET
has been combined with two proactive underlays (OLSR and BATMAN)
and with three reactive underlay routing protocols (DSR, AODV and
DYMO). In addition, the performance of the proposed system over OLSR has
been compared to two recent structured P2P over MANET systems (MA-SP2P
and E-SP2P) that adopted OLSR as the routing protocol. The results show that
better performance can be achieved using OneHopOverlay4MANET
Attack-Surface Metrics, OSSTMM and Common Criteria Based Approach to “Composable Security” in Complex Systems
In recent studies on Complex Systems and Systems-of-Systems theory, a huge effort has been put to cope with behavioral problems, i.e. the possibility of controlling a desired overall or end-to-end behavior by acting on the individual elements that constitute the system itself. This problem is particularly important in the “SMART” environments, where the huge number of devices, their significant computational capabilities as well as their tight interconnection produce a complex architecture for which it is difficult to predict (and control) a desired behavior; furthermore, if the scenario is allowed to dynamically evolve through the modification of both topology and subsystems composition, then the control problem becomes a real challenge. In this perspective, the purpose of this paper is to cope with a specific class of control problems in complex systems, the “composability of security functionalities”, recently introduced by the European Funded research through the pSHIELD and nSHIELD projects (ARTEMIS-JU programme). In a nutshell, the objective of this research is to define a control framework that, given a target security level for a specific application scenario, is able to i) discover the system elements, ii) quantify the security level of each element as well as its contribution to the security of the overall system, and iii) compute the control action to be applied on such elements to reach the security target. The main innovations proposed by the authors are: i) the definition of a comprehensive methodology to quantify the security of a generic system independently from the technology and the environment and ii) the integration of the derived metrics into a closed-loop scheme that allows real-time control of the system. The solution described in this work moves from the proof-of-concepts performed in the early phase of the pSHIELD research and enrich es it through an innovative metric with a sound foundation, able to potentially cope with any kind of pplication scenarios (railways, automotive, manufacturing, ...)
Distributed feedback-aided subspace concurrent opportunistic communications
© 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.This paper deals with the distributed subspace agreement problem for opportunistic communications in time division duplex (TDD) distributed networks. Since scenario-adapted opportunistic transmission schemes rely on locally sampled observations from the wireless environment, degrees-of-freedom (DoF) sensed as available at any node may differ. Transmitting information without agreeing the common active subspace may incur in a performance loss due to noise enhancement, energy loss and inter-system interference. In this context, we propose two subspace concurrence schemes with and without side information about neighboring user's DoF.Peer ReviewedPostprint (published version
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