912 research outputs found
Performance optimization of a UWB-based network for safety-critical avionics
To reduce the aircraft weight and maintenance costs while guaranteeing system performance and reliability, an alternative avionic communication architecture based on Ultra Wide Band (UWB) and TDMA protocol is proposed to replace the back-up part of safety-critical avionics network. The analysis and performance optimization of such a proposal is tackled as follows. First, appropriate system modeling and timing analysis, using Network Calculus and Integer Linear Programing (ILP) approach, are provided to evaluate the end-to-end delays and verify system predictability. Then, an optimization approach to find the optimal TDMA cycle duration, which minimizes the end-to-end delays, is proposed. Finally, the efficiency of our proposal to enhance the system performance is validated through a realistic avionic case study
A Survey of Air-to-Ground Propagation Channel Modeling for Unmanned Aerial Vehicles
In recent years, there has been a dramatic increase in the use of unmanned
aerial vehicles (UAVs), particularly for small UAVs, due to their affordable
prices, ease of availability, and ease of operability. Existing and future
applications of UAVs include remote surveillance and monitoring, relief
operations, package delivery, and communication backhaul infrastructure.
Additionally, UAVs are envisioned as an important component of 5G wireless
technology and beyond. The unique application scenarios for UAVs necessitate
accurate air-to-ground (AG) propagation channel models for designing and
evaluating UAV communication links for control/non-payload as well as payload
data transmissions. These AG propagation models have not been investigated in
detail when compared to terrestrial propagation models. In this paper, a
comprehensive survey is provided on available AG channel measurement campaigns,
large and small scale fading channel models, their limitations, and future
research directions for UAV communication scenarios
Determinism Enhancement and Reliability Assessment in Safety Critical AFDX Networks
RĂSUMĂ AFDX est une technologie basĂ©e sur Ethernet, qui a Ă©tĂ© dĂ©veloppĂ©e pour rĂ©pondre aux dĂ©fis qui dĂ©coulent du nombre croissant dâapplications qui transmettent des donnĂ©es de criticitĂ© variable dans les systĂšmes modernes dâavionique modulaire intĂ©grĂ©e (Integrated Modular
Avionics). Cette technologie de sĂ©curitĂ© critique a Ă©tĂ© notamment normalisĂ©e dans la partie 7 de la norme ARINC 664, dont le but est de dĂ©finir un rĂ©seau dĂ©terministe fournissant des garanties de performance prĂ©visibles. En particulier, AFDX est composĂ© de deux rĂ©seaux redondants, qui fournissent la haute fiabilitĂ© requise pour assurer son dĂ©terminisme. Le dĂ©terminisme de AFDX est principalement rĂ©alisĂ© par le concept de liens virtuels (Virtual Links), qui dĂ©finit une connexion unidirectionnelle logique entre les points terminaux (End Systems). Pour les liens virtuels, les limites supĂ©rieures des dĂ©lais de bout en bout peuvent ĂȘtre obtenues en utilisant des approches comme calcul rĂ©seau, mieux connu sous lâappellation Network Calculus. Cependant, il a Ă©tĂ© prouvĂ© que ces limites supĂ©rieures sont pessimistes dans de nombreux cas, ce qui peut conduire Ă une utilisation inefficace des ressources et augmenter la complexitĂ© de la conception du rĂ©seau. En outre, en raison de lâasynchronisme de leur fonctionnement, il existe plusieurs sources de non-dĂ©terminisme dans les rĂ©seaux AFDX. Ceci introduit un problĂšme en lien avec la dĂ©tection des dĂ©fauts en temps rĂ©el. En outre, mĂȘme si un mĂ©canisme de gestion de la redondance est utilisĂ© pour amĂ©liorer la fiabilitĂ© des rĂ©seaux AFDX, il y a un risque potentiel soulignĂ© dans la partie 7 de la norme ARINC 664. La situation citĂ©e peut causer une panne en dĂ©pit des transmissions redondantes dans certains cas particuliers. Par consĂ©quent, lâobjectif de cette thĂšse est dâamĂ©liorer la performance et la fiabilitĂ© des rĂ©seaux AFDX.
Tout dâabord, un mĂ©canisme fondĂ© sur lâinsertion de trames est proposĂ© pour renforcer le dĂ©terminisme de lâarrivĂ©e des trames au sein des rĂ©seaux AFDX. Parce que la charge du
rĂ©seau et la bande passante moyenne utilisĂ©e augmente due Ă lâinsertion de trames, une stratĂ©gie dâagrĂ©gation des Sub-Virtual Links est introduite et formulĂ©e comme un problĂšme
dâoptimisation multi-objectif. En outre, trois algorithmes ont Ă©tĂ© dĂ©veloppĂ©s pour rĂ©soudre le problĂšme dâoptimisation multi-objectif correspondant. Ensuite, une approche est introduite pour incorporer lâanalyse de la performance dans lâĂ©valuation de la fiabilitĂ© en considĂ©rant les violations des dĂ©lais comme des pannes.----------ABSTRACT AFDX is an Ethernet-based technology that has been developed to meet the challenges due to the growing number of data-intensive applications in modern Integrated Modular Avionics systems. This safety critical technology has been standardized in ARINC 664 Part 7, whose purpose is to define a deterministic network by providing predictable performance guarantees. In particular, AFDX is composed of two redundant networks, which provide the determinism
required to obtain the desired high reliability.
The determinism of AFDX is mainly achieved by the concept of Virtual Link, which defines a logical unidirectional connection from one source End System to one or more destination End Systems. For Virtual Links, the end-to-end delay upper bounds can be obtained by using the Network Calculus. However, it has been proved that such upper bounds are pessimistic in many cases, which may lead to an inefficient use of resources and aggravate network design
complexity. Besides, due to asynchronism, there exists a source of non-determinism in AFDX networks, namely frame arrival uncertainty in a destination End System. This issue introduces a problem in terms of real-time fault detection. Furthermore, although a redundancy management mechanism is employed to enhance the reliability of AFDX networks, there
still exist potential risks as pointed out in ARINC 664 Part 7, which may fail redundant transmissions in some special cases. Therefore, the purpose of this thesis is to improve the performance and the reliability of AFDX networks. First, a mechanism based on frame insertion is proposed to enhance the determinism of frame arrival within AFDX networks. As the network load and the average bandwidth used by a Virtual Link increase due to frame insertion, a Sub-Virtual Link aggregation strategy, formulated as a multi-objective optimization problem, is introduced. In addition, three algorithms have been developed to solve the corresponding multi-objective optimization problem. Next, an approach is introduced to incorporate performance analysis into reliability assessment
by considering delay violations as failures. This allowed deriving tighter probabilistic upper bounds for Virtual Links that could be applied in AFDX network certification. In order to conduct the necessary reliability analysis, the well-known Fault-Tree Analysis technique is employed and Stochastic Network Calculus is applied to compute the upper bounds with various probability limits
Transport Protocol for Future Aeronautics
Space scienc
Secure Wireless Avionics Intra-Communications the SCOTT approach
Paper presented at DecPS 2018 (held in conjunction with Ada-Europe 2018, 18-22 June, Lisbon, Portugal).This paper presents the objectives and architecture
of the use case of secure wireless avionics intracommunications of the European Project SCOTT
(secure connected trustable things). SCOTT aims to
build trust of the Internet of Things (IoT) in
industrial applications. SCOTT addresses multiple
issues such as security, safety, privacy, and
dependability across 5 industrial domains:
automotive, aeronautics, railway, building and
healthcare. The aeronautics use case focuses on the
application for active flow control (AFC) based on
dense wireless sensor and actuator networks
(DWSANs). Topics about security, vulnerabilities
and safety in the general field of wireless avionics
intra-communications (WAICs) will be addressed.
The paper presents preliminary conclusions of the
vulnerabilities and security solutions across
different entities and layers of the aeronautics IoT
architecture.info:eu-repo/semantics/publishedVersio
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