OATAO is an open access repository that collects the work of Toulouse researchers and makes it freely available over the web where possible.

The Internet of Things (IoT) enables producers of context data like sensors to interact with remote consumers of context data like smart pervasive applications in an entirely decoupled way. However, two important issues are faced by context data distribution, namely providing context information with a sufficient level of quality-i.e. quality of context, QoC-while preserving the privacy of context owners. This article presents the solutions provided by the INCOME middleware framework for addressing these two potentially contradictory issues while hiding the complexity of context data distribution in heterogeneous and large-scale environments. Context producers and consumers not only express their needs in context contracts but also the guarantees they are ready to fulfil. These contracts are then translated into advertisement and subscription filters to determine how to distribute context data. Our experiments on a first open source prototype show that QoC-based filtering and privacy protection using attributed-based access control can be performed at a reasonable cost.

International audienceMobile ad-hoc networks, MANETs, are self-organized and very dynamic systems where processes have no global knowledge of the system. In this paper, we propose a model that characterizes the dynamics of MANETs in the sense that it considers that paths between nodes are dynamically built and the system can have infinitely many processes but the network may present finite stable partitions. We also propose an algorithm that implements an eventually perfect partition participant detector PD which eventually detects the participant nodes of stable partitions

International audienceDistributed Event-Based System (DEBS) provides a versatile solution for asynchronously exchanging data in a distributed system, loosely-coupled in space and time. The software architecture of a DEBS is composed of an over-lay network of brokers that are responsible for routing data from producers to consumers. An important issue is the cost (in terms of exchanged messages) of the installation of advertisement or subscription filters on the brokers and the cost of routing notifications. The problem is exacerbated in large and heterogeneous systems involving clouds, cloudlets, desktops, laptops, mobile phones, and smart objects of the Internet of Things (IoT). In this paper, we associate the system concept of scale (of multiscale distributed systems) with the concept of scope (of DEBS) and we introduce DEBS with multiscoping. We also extend the requirements of distributed routing to deal with multiscoping. In the context of the IoT, we show in an illustrative example that the solution allows application designers and system administrators to tag advertisements and subscriptions for semantically delimiting scopes that are superpose

A 6-week-old female infant presented with pallor, hepatosplenomegaly and a leucocyte count of 329 9 10 9 /l (91% blasts). Light microscopy of the peripheral blood film showed blasts with rounded nuclei and scanty cytoplasm. No intracytoplasmic vacuoles were present (top left). Immunophenotyping by flow cytometry using peripheral blood (bottom panels) showed expression of CD10, surface membrane immunoglobulin (mu heavy chain and kappa light chain) with no expression of nuclear terminal deoxynucleotidyl transferase or CD34, indicating mature B-cell leukaemia. Cytogenetic studies showed an abnormal karyotype, 46,XX, t(X;11)(q13;q23), suggesting translocation between the MLL gene on chromosome 11 and the FOXO4 gene on chromosome X (top middle). Interphase fluorescence in situ hybridization using dual-colour break-apart probes showed the presence of an MLL gene rearrangement (top right). She was treated with a protocol designed for precursor B-cell acute lymphocytic leukaemia. However, she succumbed to sepsis in the fifth week of induction therapy.

The Internet of Things paradigm calls for exchanging data among dynamic and heterogeneous producer and consumer entities at unprecedented scales. The approach used in this paper to address IoT heterogeneity and scalability is through the modelling of multiple heterogeneous scales along dimensions of the application domain. Then, the concepts of scale and dimension of multiscalability are mapped to the concepts of scope and graph of scopes of distributed event-based systems, which have long been recognised as enabling scalable and flexible communication in a space-, time-and synchronisation-decoupled way. This multiscale approach for a distributed event-based Internet of Things enables the modelling of the decentralisation with human-centred edge computing solutions placing control at the edges of the IoT by leveraging localised scalability. Our implementation and experimentations with the MUDEBS framework show that multiscoping helps to drastically diminish the number of exchanged messages for both subscriptions and notifications.

International audienceGroup membership is a fundamental building block that facilitates the development of fault-tolerant systems. The specification of group membership in partitionable systems has not yet reached the same level of maturity as in primary partition systems. Existing specifications do not satisfy the following two antagonistic requirements: (i) the specification must be weak enough to be solvable (implementable); (ii) it must be strong enough to simplify the design of fault-tolerant distributed applications in partitionable systems. In this article, we propose: (1) a new distributed system model that takes into account the formation of dynamic paths, (2) a specification of partitionable group membership for MANETS called PGM, and (3) an implementation of PGM designed by adapting a well-known solution of primary partition group membership, namely Paxos. This results in the specification of an abortable consensus as the combination of two abstractions: an eventual α partition-participant detector and an eventual register per partition that guarantee liveness and safety per partition, respectively. Then, partitionable group membership is solved by transformation into a sequence of abortable consensusGroup membership is a fundamental building block that facilitates the development of fault-tolerant systems. The specification of group membership in partitionable systems has not yet reached the same level of maturity as in primary partition systems. Existing specifications do not satisfy the following two antagonistic requirements: (i) the specification must be weak enough to be solvable (implementable); (ii) it must be strong enough to simplify the design of fault-tolerant distributed applications in partitionable systems. In this article, we propose: (1) a new distributed system model that takes into account the formation of dynamic paths, (2) a specification of partitionable group membership for MANETS called PGM, and (3) an implementation of PGM designed by adapting a well-known solution of primary partition group membership, namely Paxos. This results in the specification of an abortable consensus as the combination of two abstractions: an eventual α partition-participant detector and an eventual register per partition that guarantee liveness and safety per partition, respectively. Then, partitionable group membership is solved by transformation into a sequence of abortable consensus

The tremendous amount of context information that can be generated by the Internet of Things (IoT) calls for new solutions able to dig for the relevant information fitting applications' needs. This paper proposes to leverage multiscale-, Quality of Context (QoC)-and privacy-awareness for the efficient filtering of context information disseminated between the decoupled producers and consumers of the IoT. We first discuss some specific challenges that must be addressed by next generation context managers, including multiscalability, distributed push and pull communications, and the consideration of both QoC and privacy constraints. We then answer these challenges with a new context dissemination framework involving visibility and forwarding filters and illustrate it through the implementation of a collaborative social welfare scenario.