Modelling Clock Synchronization in the Chess gMAC WSN Protocol

We present a detailled timed automata model of the clock synchronization algorithm that is currently being used in a wireless sensor network (WSN) that has been developed by the Dutch company Chess. Using the Uppaal model checker, we establish that in certain cases a static, fully synchronized network may eventually become unsynchronized if the current algorithm is used, even in a setting with infinitesimal clock drifts

Proposition et vérification formelle de protocoles de communications temps-réel pour les réseaux de capteurs sans fil

Les RCsF sont des réseaux ad hoc, sans fil, large échelle déployés pour mesurer des paramètres de l'environnement et remonter les informations à un ou plusieurs emplacements (nommés puits). Les éléments qui composent le réseau sont de petits équipements électroniques qui ont de faibles capacités en termes de mémoire et de calcul ; et fonctionnent sur batterie. Ces caractéristiques font que les protocoles développés, dans la littérature scientifique de ces dernières années, visent principalement à auto-organiser le réseau et à réduire la consommation d'énergie. Avec l'apparition d'applications critiques pour les réseaux de capteurs sans fil, de nouveau besoins émergent, comme le respect de bornes temporelles et de fiabilité. En effet, les applications critiques sont des applications dont dépendent des vies humaines ou l'environnement, un mauvais fonctionnement peut donc avoir des conséquences catastrophiques. Nous nous intéressons spécifiquement aux applications de détection d'événements et à la remontée d'alarmes (détection de feu de forêt, d'intrusion, etc), ces applications ont des contraintes temporelles strictes. D'une part, dans la littérature, on trouve peu de protocoles qui permettent d'assurer des délais de bout en bout bornés. Parmi les propositions, on trouve des protocoles qui permettent effectivement de respecter des contraintes temporelles mais qui ne prennent pas en compte les spécificités des RCsF (énergie, large échelle, etc). D'autres propositions prennent en compte ces aspects, mais ne permettent pas de garantir des bornes temporelles. D'autre part, les applications critiques nécessitent un niveau de confiance très élevé, dans ce contexte les tests et simulations ne suffisent pas, il faut être capable de fournir des preuves formelles du respect des spécifications. A notre connaissance cet aspect est très peu étudié pour les RcsF. Nos contributions sont donc de deux types : * Nous proposons un protocole de remontée d'alarmes, en temps borné, X-layer (MAC/routage, nommé RTXP) basé sur un système de coordonnées virtuelles originales permettant de discriminer le 2-voisinage. L'exploitation de ces coordonnées permet d'introduire du déterminisme et de construire un gradient visant à contraindre le nombre maximum de sauts depuis toute source vers le puits. Nous proposons par ailleurs un mécanisme d'agrégation temps-réel des alarmes remontées pour lutter contre les tempêtes de détection qui entraînent congestion et collision, et donc limitent la fiabilité du système. * Nous proposons une méthodologie de vérification formelle basée sur les techniques de Model Checking. Cette méthodologie se déroule en trois points, qui visent à modéliser de manière efficace la nature diffusante des réseaux sans fil, vérifier les RCsF en prenant en compte la non-fiabilité du lien radio et permettre le passage à l'échelle de la vérification en mixant Network Calculus et Model Checking. Nous appliquons ensuite cette méthodologie pour vérifier RTXP.Wireless Sensor Networks (WSNs) are ad hoc wireless large scale networks deployed in order to monitor physical parameters of the environment and report the measurements to one or more nodes of the network (called sinks). The small electronic devices which compose the network have low computing and memory capacities and run on batteries, researches in this field have thus focused mostly on self-organization and energy consumption reduction aspects. Nevertheless, critical applications for WSNs are emerging and require more than those aspects, they have real-time and reliability requirements. Critical applications are applications on which depend human lives and the environment, a failure of a critical application can thus have dramatic consequences. We are especially interested in anomaly detection applications (forest fire detection, landslide detection, intrusion detection, etc), which require bounded end to end delays and high delivery ratio. Few WSNs protocols of the literature allow to bound end to end delays. Among the proposed solutions, some allow to effectively bound the end to end delays, but do not take into account the characteristics of WSNs (limited energy, large scale, etc). Others, take into account those aspects, but do not give strict guaranties on the end to end delays. Moreover, critical applications require a very high confidence level, simulations and tests are not sufficient in this context, formal proofs of compliance with the specifications of the application have to be provided. The application of formal methods to WSNs is still an open problem. Our contributions are thus twofold : * We propose a real-time cross-layer protocol for WSNs (named RTXP) based on a virtual coordinate system which allows to discriminate nodes in a 2-hop neighborhood. Thanks to these coordinates it is possible to introduce determinism in the accesses to the medium and to bound the hop-count, this allows to bound the end to end delay. Besides, we propose a real-time aggregation scheme to mitigate the alarm storm problem which causes collisions and congestion and thus limit the network lifetime. * We propose a formal verification methodology based on the Model Checking technique. This methodology is composed of three elements, (1) an efficient modeling of the broadcast nature of wireless networks, (2) a verification technique which takes into account the unreliability of the wireless link and (3) a verification technique which mixes Network Calculus and Model Checking in order to be both scalable and exhaustive. We apply this methodology in order to formally verify our proposition, RTXP.VILLEURBANNE-DOC'INSA-Bib. elec. (692669901) / SudocSudocFranceF

Wireless propagation studies in highly resonant and dynamic environments

This thesis develops efficient tools for modelling wireless communications within highly resonant environments. The aim of these tools is to augment analysis of wireless systems inside closed metallic cavity environments. The primary application for these systems is within the aerospace industry where weight and space are restricted and robustness is critical. The use of ever-advancing wireless communication options would offer significant weight and cost savings and increase safety through supplementing or the replacement of wired systems. The use of a low power wireless system offers the greatest advantage in terms of flexibility and weight. Accordingly, the most suitable applications of the wireless systems are discussed in terms of existing avionic systems. The electromagnetic properties of the aircraft environment and parameters to characterise both the properties of the environment and the wireless signal are introduced. Efficient models are then developed, which characterise the resonant and associated multipath nature of the cavity based on an equivalent circuit approach. The efficiency of these models permits the use of a statistical modelling approach, akin to reverberation chamber measurement techniques, in order to generalise the results for typically non-constant modal structures. Finally, a fractional boundary placement model is developed to augment the transmission line modelling method and permit boundary placement at non-integer positions within a structured mesh. The technique provides a semi-conformal capability with no deleterious impact on the modelling time step. This is then extended to a dynamic model for modelling structural variations during the simulation. A subset of wireless communication approaches is presented and the effectiveness and suitability of such systems are discussed. The developed models are applied to characteristic environments and a selection of the wireless communication methodologies in order to provide examples of their use and an insight into the effect of these environments upon a wireless system

Recent Advances in Wireless Communications and Networks

This book focuses on the current hottest issues from the lowest layers to the upper layers of wireless communication networks and provides "real-time" research progress on these issues. The authors have made every effort to systematically organize the information on these topics to make it easily accessible to readers of any level. This book also maintains the balance between current research results and their theoretical support. In this book, a variety of novel techniques in wireless communications and networks are investigated. The authors attempt to present these topics in detail. Insightful and reader-friendly descriptions are presented to nourish readers of any level, from practicing and knowledgeable communication engineers to beginning or professional researchers. All interested readers can easily find noteworthy materials in much greater detail than in previous publications and in the references cited in these chapters

Smart data management with BIM for Architectural Heritage

In the last years smart buildings topic has received much attention as well as Building Information Modelling (BIM) and interoperability as independent fields. Linking these topics is an essential research target to help designers and stakeholders to run processes more efficiently. Working on a smart building requires the use of Innovation and Communication Technology (ICT) to optimize design, construction and management. In these terms, several technologies such as sensors for remote monitoring and control, building equipment, management software, etc. are available in the market. As BIM provides an enormous amount of information in its database and theoretically it is able to work with all kind of data sources using interoperability, it is essential to define standards for both data contents and format exchange. In this way, a possibility to align research activity with Horizon 2020 is the investigation of energy saving using ICT. Unfortunately, comparing the Architecture Engineering and Construction (AEC) Industry with other sectors it is clear how in the building field advanced information technology applications have not been adopted yet. However in the last years, the adoption of new methods for the data management has been investigated by many researchers. So, basing on the above considerations, the main purpose of this thesis is investigate the use of BIM methodology relating to existing buildings concerning on three main topics: • Smart data management for architectural heritage preservation; • District data management for energy reduction; • The maintenance of highrises. For these reasons, data management acquires a very important value relating to the optimization of the building process and it is considered the most important goal for this research. Taking into account different kinds of architectural heritage, the attention is focused on the existing and historical buildings that usually have characterized by several constraints. Starting from data collection, a BIM model was developed and customized in function of its objectives, and providing information for different simulation tests. Finally, data visualization was investigated through the Virtual Reality(VR) and Augmented Reality (AR). Certainly, the creation of a 3D parametric model implies that data is organized according to the use of individual users that are involved in the building process. This means that each 3D model can be developed with different Levels of Detail/Development (LODs) basing on the goal of the data source. Along this thesis the importance of LODs is taken into account related to the kind of information filled in a BIM model. In fact, basing on the objectives of each project a BIM model can be developed in a different way to facilitate the querying data for the simulations tests.\ud The three topics were compared considering each step of the building process workflow, highlighting the main differences, evaluating the strengths and weaknesses of BIM methodology. In these terms, the importance to set a BIM template before the modelling step was pointed out, because it provides the possibility to manage information in order to be collected and extracted for different purposes and by specific users. Moreover, basing on the results obtained in terms of the 3D parametric model and in terms of process, a proper BIM maturity level was determined for each topic. Finally, the value of interoperability was arisen from these tests considering that it provided the opportunity to develop a framework for collaboration, involving all parties of the building industry

AI Knowledge Transfer from the University to Society

AI Knowledge Transfer from the University to Society: Applications in High-Impact Sectors brings together examples from the "Innovative Ecosystem with Artificial Intelligence for Andalusia 2025" project at the University of Seville, a series of sub-projects composed of research groups and different institutions or companies that explore the use of Artificial Intelligence in a variety of high-impact sectors to lead innovation and assist in decision-making. Key Features Includes chapters on health and social welfare, transportation, digital economy, energy efficiency and sustainability, agro-industry, and tourism Great diversity of authors, expert in varied sectors, belonging to powerful research groups from the University of Seville with proven experience in the transfer of knowledge to the productive sector and agents attached to the Andalucía TECH Campu