Search results for "Distributed System"
showing 10 items of 48 documents
Mutual entity authentication for LTE
2011
In this paper we outline the Authentication and Key Agreement protocol (EPS-AKA) found in Long-Term Evolution (LTE) systems. This architecture is the 3GPP version of a 4G access security architecture. The LTE security architecture is a mature evolved architecture, with both strengths and weaknesses. In this paper we propose an amendment to the EPS-AKA protocol to make it a full mutual (online) entity authentication protocol. We also analyze the proposal, highlighting both the improvements and the drawbacks of the new AKA protocol.
The Max-Product Algorithm Viewed as Linear Data-Fusion: A Distributed Detection Scenario
2019
In this paper, we disclose the statistical behavior of the max-product algorithm configured to solve a maximum a posteriori (MAP) estimation problem in a network of distributed agents. Specifically, we first build a distributed hypothesis test conducted by a max-product iteration over a binary-valued pairwise Markov random field and show that the decision variables obtained are linear combinations of the local log-likelihood ratios observed in the network. Then, we use these linear combinations to formulate the system performance in terms of the false-alarm and detection probabilities. Our findings indicate that, in the hypothesis test concerned, the optimal performance of the max-product a…
Statistical Modeling and Analysis of Mobile-to-Mobile Fading Channels in Cooperative Networks Under Line-of-Sight Conditions
2009
Published version of an article from the journal: Wireless Personal Communications. The original publication is available at Springerlink. http://dx.doi.org/10.1007/s11277-009-9721-4 Recently, mobile-to-mobile (M2M) cooperative network technology has gained considerable attention for its promise of enhanced system performance with increased mobility support. As this is a new research field, little is known about the statistical properties of M2M fading channels in cooperative networks. So far, M2M fading channels have mainly been modeled under the assumption of non-line-of-sight (NLOS) conditions. In this paper, we propose a new model for M2M fading channels in amplify-and-forward relay lin…
Tracking control of network distributed systems in presence of variable time delay and loss of information
2006
This paper deals with the control of network distributed systems which has been at the centre of interest in a wide area of research in the last few year. The control of such systems is very difficult because the communication networks inevitably introduce variable time delays and possible lost of samples. In particular, it is proposed an extension of the approach, derived in the contest of the optimal stochastic regulator problem [1], [2], to the remote tracking problem considering a distributed control system in which the signals from the transducers to the controller and from the controller to the actuator are transmitted through a communication network with variable delays and possible …
A distributed genetic algorithm for restoration of vertical line scratches
2008
This paper reports a distributed algorithm for the restoration of still frames corrupted by vertical line scratches. The restoration is here approached as an optimisation problem, and is solved using an ad-hoc Genetic Algorithm. The distributed algorithm is designed following a pipeline logical structure. The front end is a network of standard workstations with heterogeneous operating systems. The quality of image is appreciable and the computational time is quite low with respect the sequential version.
Testing wearable IoT applications through sensor virtualization
2020
The development of distributed IoT applications requires the integration of data provided by different sensors embedded in multiple devices. As an example, an application for health monitoring in an assisted living scenario may include several wearable and fixed nodes each carrying different sensors and running specific code. Verifying that the application is properly working according to the specifications requires assessing that the code of each node behaves consistently in all the possible use cases. Tests involving sensor data may be difficult or costly to replicate realistically and this could also slow down the development of the application in its early stages. In this paper we intro…
A secure architecture for P2PSIP-based communication systems
2009
Today, Peer-to-Peer SIP based communication systems have attracted much attention from both academia and industry. The decentralized nature of P2P might provide the distributed peer-to-peer communication system without help of the traditional SIP server. However, it comes to the cost of reduced manageability and therefore causes security problems, e.g. distrust, privacy leaks, unpredictable availability, etc. In this paper, we investigate on P2PSIP security issues and propose a proxy-based system architecture that improves security during P2PSIP session initiation. The main issues considered in this architecture include Source inter-working, Encryption & Decryption, Policy Management, Desti…
Logical Consensus for Distributed Network Agreement
2008
In this paper we introduce a novel consensus mechanism where agents of a network are able to share logical values, or Booleans, representing their local opinions on e.g. the presence of an intruder or of a fire within an indoor environment. Under suitable joint conditions on agents? visibility and communication capability, we provide an algorithm generating a logical linear consensus system that is globally stable. The solution is optimal in terms of the number of messages to be exchanged and the time needed to reach a consensus. Moreover, to cope with possible sensor failure, we propose a second design approach that produces robust logical nonlinear consensus systems tolerating a maximum n…
Design and Simulation of Narrowband Indoor Radio Propagation Channels under LOS and NLOS Propagation Conditions
2010
Paper presented at the 2010 IEEE 71st Vehicular Technology Conference. (c) 2010 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, 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 components of this work in other works. Paper also available from the publisher: http://dx.doi.org/10.1109/VETECS.2010.5494116 This paper deals with the design and simulation of narrowband indoor propagation channels under line-of-sight (LOS) and non-LOS (NLOS) propagation conditions. We propose a reference cha…
An Exact Solution for the Level-Crossing Rate and the Average Duration of Fades of the Envelope of Sum-of-Cisoids Processes
2012
Authors version of an article published in the journal: Procedia Technology. Also available from the publisher at: http://dx.doi.org/10.1016/j.protcy.2012.03.004 Sum-of-cisoids (SOC) processes provide a physically and numerically appealing framework for the modelling and simulation of a wide class of mobile radio channels. This paper is concerned with the problem of finding a general solution for the level-crossing rate (LCR) and the average duration of fades (ADF) of the envelope of SOC processes. Exact expressions are derived for the LCR and the ADF by taking into account that the inphase component, the quadrature component, and the time derivatives of the inphase and quadrature component…