7,727 research outputs found
Towards a Formal Framework for Mobile, Service-Oriented Sensor-Actuator Networks
Service-oriented sensor-actuator networks (SOSANETs) are deployed in
health-critical applications like patient monitoring and have to fulfill strong
safety requirements. However, a framework for the rigorous formal modeling and
analysis of SOSANETs does not exist. In particular, there is currently no
support for the verification of correct network behavior after node failure or
loss/addition of communication links. To overcome this problem, we propose a
formal framework for SOSANETs. The main idea is to base our framework on the
\pi-calculus, a formally defined, compositional and well-established formalism.
We choose KLAIM, an existing formal language based on the \pi-calculus as the
foundation for our framework. With that, we are able to formally model SOSANETs
with possible topology changes and network failures. This provides the basis
for our future work on prediction, analysis and verification of the network
behavior of these systems. Furthermore, we illustrate the real-life
applicability of this approach by modeling and extending a use case scenario
from the medical domain.Comment: In Proceedings FESCA 2013, arXiv:1302.478
Task allocation in dynamic networks of satellites
The management of distributed satellite systems requires the coordination of a large number of heterogeneous spacecraft. Task allocation in such a system is complicated by limited communication and individual satellite dynamics. Previous work has shown that task allocation using a market-based mechanism can provide scalable and efficient management of static networks; in this paper we extend this work to determine the impact of dynamic topologies. We develop a Keplerian mobility model to describe the topology of the communication network over time. This movement model is then used in simulation to show that the task allocation mechanism does not show a significant decrease in effectiveness from the static case, reflecting the suitability distributed market-based control to the highly dynamic environment
Evaluation of network coding techniques for a sniper detection application
This paper experimentally studies the reliability and delay of flooding based multicast protocols for a sniper detection application. In particular using an emulator it studies under which conditions protocols based on network coding deliver performance improvements compared to classic flooding. It then presents an implementation of such protocols on mobile phones
OpenKnowledge at work: exploring centralized and decentralized information gathering in emergency contexts
Real-world experience teaches us that to manage emergencies, efficient crisis response coordination is crucial; ICT infrastructures are effective in supporting the people involved in such contexts, by supporting effective ways of interaction. They also should provide innovative means of communication and information management. At present, centralized architectures are mostly used for this purpose; however, alternative infrastructures based on the use of distributed information sources, are currently being explored, studied and analyzed. This paper aims at investigating the capability of a novel approach (developed within the European project OpenKnowledge1) to support centralized as well as decentralized architectures for information gathering. For this purpose we developed an agent-based e-Response simulation environment fully integrated with the OpenKnowledge infrastructure and through which existing emergency plans are modelled and simulated. Preliminary results show the OpenKnowledge capability of supporting the two afore-mentioned architectures and, under ideal assumptions, a comparable performance in both cases
Electronically-switched Directional Antennas for Low-power Wireless Networks: A Prototype-driven Evaluation
We study the benefits of electronically-switched directional antennas in low-power wireless networks. This antenna technology may improve energy efficiency by increasing the communication range and by alleviating contention in directions other than the destination, but in principle requires a dedicated network stack. Unlike most existing works, we start by characterizing a real-world antenna prototype, and apply this to an existing low-power wireless stack, which we adapt with minimal changes. Our results show that: i) the combination of a low-cost directional antenna and a conventional network stack already brings significant performance improvements, e.g., nearly halving the radio-on time per delivered packet; ii) the margin of improvement available to alternative clean-slate protocol designs is similarly large and concentrated in the control rather than the data plane; iii) by artificially modifying our antenna's link-layer model, we can point at further potential benefits opened by different antenna designs
A Faster Counting Protocol for Anonymous Dynamic Networks
We study the problem of counting the number of nodes in a slotted-time
communication network, under the challenging assumption that nodes do not have
identifiers and the network topology changes frequently. That is, for each time
slot links among nodes can change arbitrarily provided that the network is
always connected. Tolerating dynamic topologies is crucial in face of mobility
and unreliable communication whereas, even if identifiers are available, it
might be convenient to ignore them in massive networks with changing topology.
Counting is a fundamental task in distributed computing since knowing the size
of the system often facilitates the design of solutions for more complex
problems. Currently, the best upper bound proved on the running time to compute
the exact network size is double-exponential. However, only linear complexity
lower bounds are known, leaving open the question of whether efficient Counting
protocols for Anonymous Dynamic Networks exist or not. In this paper we make a
significant step towards answering this question by presenting a distributed
Counting protocol for Anonymous Dynamic Networks which has exponential time
complexity. Our algorithm ensures that eventually every node knows the exact
size of the system and stops executing the algorithm. Previous Counting
protocols have either double-exponential time complexity, or they are
exponential but do not terminate, or terminate but do not provide running-time
guarantees, or guarantee only an exponential upper bound on the network size.
Other protocols are heuristic and do not guarantee the correct count
PADS: Practical Attestation for Highly Dynamic Swarm Topologies
Remote attestation protocols are widely used to detect device configuration
(e.g., software and/or data) compromise in Internet of Things (IoT) scenarios.
Unfortunately, the performances of such protocols are unsatisfactory when
dealing with thousands of smart devices. Recently, researchers are focusing on
addressing this limitation. The approach is to run attestation in a collective
way, with the goal of reducing computation and communication. Despite these
advances, current solutions for attestation are still unsatisfactory because of
their complex management and strict assumptions concerning the topology (e.g.,
being time invariant or maintaining a fixed topology). In this paper, we
propose PADS, a secure, efficient, and practical protocol for attesting
potentially large networks of smart devices with unstructured or dynamic
topologies. PADS builds upon the recent concept of non-interactive attestation,
by reducing the collective attestation problem into a minimum consensus one. We
compare PADS with a state-of-the art collective attestation protocol and
validate it by using realistic simulations that show practicality and
efficiency. The results confirm the suitability of PADS for low-end devices,
and highly unstructured networks.Comment: Submitted to ESORICS 201
Formal analysis techniques for gossiping protocols
We give a survey of formal verification techniques that can be used to corroborate existing experimental results for gossiping protocols in a rigorous manner. We present properties of interest for gossiping protocols and discuss how various formal evaluation techniques can be employed to predict them
MAGDA: A Mobile Agent based Grid Architecture
Mobile agents mean both a technology
and a programming paradigm. They allow for a
flexible approach which can alleviate a number
of issues present in distributed and Grid-based
systems, by means of features such as migration,
cloning, messaging and other provided mechanisms.
In this paper we describe an architecture
(MAGDA – Mobile Agent based Grid Architecture)
we have designed and we are currently
developing to support programming and execution
of mobile agent based application upon Grid
systems
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