Conception d'un modèle architectural collaboratif pour l'informatique omniprésente à la périphérie des réseaux mobiles

Le progrès des technologies de communication pair-à-pair et sans fil a de plus en plus permis l’intégration de dispositifs portables et omniprésents dans des systèmes distribués et des architectures informatiques de calcul dans le paradigme de l’internet des objets. De même, ces dispositifs font l'objet d'un développement technologique continu. Ainsi, ils ont toujours tendance à se miniaturiser, génération après génération durant lesquelles ils sont considérés comme des dispositifs de facto. Le fruit de ces progrès est l'émergence de l'informatique mobile collaborative et omniprésente, notamment intégrée dans les modèles architecturaux de l'Internet des Objets. L’avantage le plus important de cette évolution de l'informatique est la facilité de connecter un grand nombre d'appareils omniprésents et portables lorsqu'ils sont en déplacement avec différents réseaux disponibles. Malgré les progrès continuels, les systèmes intelligents mobiles et omniprésents (réseaux, dispositifs, logiciels et technologies de connexion) souffrent encore de diverses limitations à plusieurs niveaux tels que le maintien de la connectivité, la puissance de calcul, la capacité de stockage de données, le débit de communications, la durée de vie des sources d’énergie, l'efficacité du traitement de grosses tâches en termes de partitionnement, d'ordonnancement et de répartition de charge. Le développement technologique accéléré des équipements et dispositifs de ces modèles mobiles s'accompagne toujours de leur utilisation intensive. Compte tenu de cette réalité, plus d'efforts sont nécessaires à la fois dans la conception structurelle tant au matériel et logiciel que dans la manière dont il est géré. Il s'agit d'améliorer, d'une part, l'architecture de ces modèles et leurs technologies de communication et, d'autre part, les algorithmes d'ordonnancement et d'équilibrage de charges pour effectuer leurs travaux efficacement sur leurs dispositifs. Notre objectif est de rendre ces modèles omniprésents plus autonomes, intelligents et collaboratifs pour renforcer les capacités de leurs dispositifs, leurs technologies de connectivité et les applications qui effectuent leurs tâches. Ainsi, nous avons établi un modèle architectural autonome, omniprésent et collaboratif pour la périphérie des réseaux. Ce modèle s'appuie sur diverses technologies de connexion modernes telles que le sans-fil, la radiocommunication pair-à-pair, et les technologies offertes par LoPy4 de Pycom telles que LoRa, BLE, Wi-Fi, Radio Wi-Fi et Bluetooth. L'intégration de ces technologies permet de maintenir la continuité de la communication dans les divers environnements, même les plus sévères. De plus, ce modèle conçoit et évalue un algorithme d'équilibrage de charge et d'ordonnancement permettant ainsi de renforcer et améliorer son efficacité et sa qualité de service (QoS) dans différents environnements. L’évaluation de ce modèle architectural montre des avantages tels que l’amélioration de la connectivité et l’efficacité d’exécution des tâches. Advances in peer-to-peer and wireless communication technologies have increasingly enabled the integration of mobile and pervasive devices into distributed systems and computing architectures in the Internet of Things paradigm. Likewise, these devices are subject to continuous technological development. Thus, they always tend to be miniaturized, generation after generation during which they are considered as de facto devices. The success of this progress is the emergence of collaborative mobiles and pervasive computing, particularly integrated into the architectural models of the Internet of Things. The most important benefit of this form of computing is the ease of connecting a large number of pervasive and portable devices when they are on the move with different networks available. Despite the continual advancements that support this field, mobile and pervasive intelligent systems (networks, devices, software and connection technologies) still suffer from various limitations at several levels such as maintaining connectivity, computing power, ability to data storage, communication speeds, the lifetime of power sources, the efficiency of processing large tasks in terms of partitioning, scheduling and load balancing. The accelerated technological development of the equipment and devices of these mobile models is always accompanied by their intensive use. Given this reality, it requires more efforts both in their structural design and management. This involves improving on the one hand, the architecture of these models and their communication technologies, and, on the other hand, the scheduling and load balancing algorithms for the work efficiency. The goal is to make these models more autonomous, intelligent, and collaborative by strengthening the different capabilities of their devices, their connectivity technologies and the applications that perform their tasks. Thus, we have established a collaborative autonomous and pervasive architectural model deployed at the periphery of networks. This model is based on various modern connection technologies such as wireless, peer-to-peer radio communication, and technologies offered by Pycom's LoPy4 such as LoRa, BLE, Wi-Fi, Radio Wi-Fi and Bluetooth. The integration of these technologies makes it possible to maintain the continuity of communication in the various environments, even the most severe ones. Within this model, we designed and evaluated a load balancing and scheduling algorithm to strengthen and improve its efficiency and quality of service (QoS) in different environments. The evaluation of this architectural model shows payoffs such as improvement of connectivity and efficiency of task executions

Internet-of-Things (IoT) shortest path algorithms and communication case studies for maintaining connectivity in harsh environements

Research on the shortest path in networks to maintain connectivity in the Internet of Things (IoT) remains an important issue for determining minimal routes, especially in terms of time and distance, between two devices at distinct points (i.e., nodes) of the network. Many constraints exist for IoT smart devices for transmitting a large amount of information and data, such as limited resources, energy, and time consumption, as well as the potential for overwhelmed communication traffic. Several algorithms were designed and implemented to address these problems that can be simulated and considered as information message passing. The search space is often modeled by a graph, where each node corresponds to a location of a smart device, and the edges represent the paths or links that carry messages, while the absence of a path between two nodes designates a communication breakdown or obstacle. Existing pathfinding algorithms are incorporated in applications, such as Google Maps, rescue people, video games, online packet routing, and rescue applications used in harsh environments. For these latter scenarios, the infrastructure for various technologies of communication becomes vulnerable and dysfunctional, so maintaining connectivity and finding the shortest path becomes a priority. Our goal is to remedy this problem by taking advantage of modernized peer-to-peer wireless technologies, such as Wi-Fi Direct, which can be improved through autonomous wireless technology kits like Lopy 4 of Pycom, and through two alternatives of moving devices (nodes) or service drones. This paper investigates several shortest path algorithms and identifies three case studies to maintain connectivity in harsh environments

Molecular characterization of staphylococcal cassette chromosome mec and virulence encoding genes in methicillin-resistant staphylococci at a medical center in Lebanon

Background: Methicillin-resistant staphylococci (MRS) are major human pathogens accounting for most hospital-acquired (HA) and community acquired (CA) infections worldwide. The recent increase in MRS in a medical center in Lebanon elicited the determination of SCCmec types, genotypes, and prevalence of Panton-Valentine leucociden (PVL) and toxic shock syndrome toxin-1 (TSST-1) among the MRS isolates.   Methods: Thirty-six MRS isolates collected between October 2010 and September 2011 at a medical center, Lebanon were typed using phenotypic and genotypic methods. Antimicrobial susceptibility was determined using the disk diffusion agar method. SCCmec typing was performed by multiplex PCR and sequence analysis. The prevalence of the genes encoding PVL and TSST-1 virulence factors and their transcription levels, were determined respectively by PCR and semi-quantitative real-time PCR. The genomic relatedness of the isolates was assessed by random amplified polymorphic DNA (RAPD) analysis.Results: Antimicrobial susceptibility revealed three distinct antibiotypes. The predominant SCCmec type found among the MRS isolates was type IVa (51%). Twenty-nine percent harbored SCCmec type III and 14% harbored SCCmec type II. One isolate harbored SCCmec type IVc, and another  harbored SCCmec type I. All methicillin-resistant Staphylococcus aureus (MRSA) isolates were negative for the gene encoding for PVL, and two were positive for the gene encoding for TSST-1. RAPD analysis demonstrated high genomic diversity among the MRS isolates.Conclusion: This study demonstrated the SCCmec types and the clonality of the MRS strains, allowing the differentiation between HA and CA-MRS strains. CA-MRS have  increased  in the hospital environment and rendered highly resistant to erythromycin and clindamycin

Génération de plans réactifs basée sur l'abstraction

La planification peut être définie comme un processus permettant de poursuivre et d'atteindre des objectifs précis. L'abstraction a longtemps été perçue par les chercheurs comme une manière subtile d'analyser et de simplifier les systèmes de grande taille. Dans ce mémoire, nous proposons une approche de planification qui, croyons-nous, accroîtra le rendement dans les systèmes de grande taille. Lorsque le problème à étudier est modélisé par un graphe, nous créons un autre graphe abstrait en groupant des parties du graphe initial. Dans chaque sous-graphe, nous appliquons l'algorithme d'itération de politique, ceci en vue de produire une politique partielle optimale. Les politiques assemblées à partir des sous-graphes forment une politique optimale du graphe initial

Génération de plans réactifs basée sur l'abstraction

La planification peut être définie comme un processus permettant de poursuivre et d'atteindre des objectifs précis. L'abstraction a longtemps été perçue par les chercheurs comme une manière subtile d'analyser et de simplifier les systèmes de grande taille. Dans ce mémoire, nous proposons une approche de planification qui, croyons-nous, accroîtra le rendement dans les systèmes de grande taille. Lorsque le problème à étudier est modélisé par un graphe, nous créons un autre graphe abstrait en groupant des parties du graphe initial. Dans chaque sous-graphe, nous appliquons l'algorithme d'itération de politique, ceci en vue de produire une politique partielle optimale. Les politiques assemblées à partir des sous-graphes forment une politique optimale du graphe initial

Layered architectural model for collaborative computing in peripheral autonomous networks of mobile devices

Collaborative mobile computing is today one of the most popular paradigms of computing because of its impact on the performance and expansion of distributed systems and therefore on the development of Internet of Things. Due to the rapid progress in technologies of communication and smart mobile devices with the growing trend towards its use, many architectures of mobile collaborative computing have emerged to improve and organize the expand of Internet of Things, such as Cloud, Cloudlet, Fog, Edge, Mobile Edge, Mobile Cloudlet Computing, etc. In this paper, we first review their current layered architectural models and discuss their limits and challenges. Then, we will present a new architectural model: Collaborative Autonomous Networks of Mobile Devices Using Peer-to-Peer Communication that can be applied in many areas. Finally, a scenario of an emergency situation is presented to illustrate and highlight its requirements, such as supporting connectivity and engineering of data and services. Also, how the rescue process is addressing across different architecture layers

A Greedy Scheduling Approach for Peripheral Mobile Intelligent Systems

Smart, pervasive devices have recently experienced accelerated technological development in the fields of hardware, software, and wireless connections. The promotion of various kinds of collaborative mobile computing requires an upgrade in network connectivity with wireless technologies, as well as enhanced peer-to-peer communication. Mobile computing also requires appropriate scheduling methods to speed up the implementation and processing of various computing applications by better managing network resources. Scheduling techniques are relevant to the modern architectural models that support the IoT paradigm, particularly smart collaborative mobile computing architectures at the network periphery. In this regard, load-balancing techniques have also become necessary to exploit all the available capabilities and thus the speed of implementation. However, since the problem of scheduling and load-balancing, which we addressed in this study, is known to be NP-hard, the heuristic approach is well justified. We thus designed and validated a greedy scheduling and load-balancing algorithm to improve the utilization of resources. We conducted a comparison study with the longest cloudlet fact processing (LCFP), shortest cloudlet fact processing (SCFP), and Min-Min heuristic algorithms. The choice of those three algorithms is based on the efficiency and simplicity of their mechanisms, as reported in the literature, for allocating tasks to devices. The simulation we conducted showed the superiority of our approach over those algorithms with respect to the overall completion time criterion

A Pervasive Collaborative Architectural Model at the Network’s Periphery

Pervasive collaborative computing within the Internet of Things (IoT) has progressed rapidly over the last decade. Nevertheless, emerging architectural models and their applications still suffer from limited capacity in areas like power, efficient computing, memory, connectivity, latency and bandwidth. Technological development is still in progress in the fields of hardware, software and wireless communications. Their communication is usually done via the Internet and wireless via base stations. However, these models are sometimes subject to connectivity failures and limited coverage. The models that incorporate devices with peer-to-peer (P2P) communication technologies are of great importance, especially in harsh environments. Nevertheless, their power-limited devices are randomly distributed on the periphery where their availability can be limited and arbitrary. Despite these limitations, their capabilities and efficiency are constantly increasing. Accelerating development in these areas can be achieved by improving architectures and technologies of pervasive collaborative computing, which refers to the collaboration of mobile and embedded computing devices. To enhance mobile collaborative computing, especially in the models acting at the network’s periphery, we are interested in modernizing and strengthening connectivity using wireless technologies and P2P communication. Therefore, the main goal of this paper is to enhance and maintain connectivity and improve the performance of these pervasive systems while performing the required and expected services in a challenging environment. This is especially important in catastrophic situations and harsh environments, where connectivity is used to facilitate and enhance rescue operations. Thus, we have established a resilient mobile collaborative architectural model comprising a peripheral autonomous network of pervasive devices that considers the constraints of these resources. By maintaining the connectivity of its devices, this model can operate independently of wireless base stations by taking advantage of emerging P2P connection technologies such as Wi-Fi Direct and those enabled by LoPy4 from Pycom such as LoRa, BLE, Sigfox, Wi-Fi, Radio Wi-Fi and Bluetooth. Likewise, we have designed four algorithms to construct a group of devices, calculate their scores, select a group manager, and exchange inter- and intra-group messages. The experimental study we conducted shows that this model continues to perform efficiently, even in circumstances like the breakdown of wireless connectivity due to an extreme event or congestion from connecting a huge number of devices

MCCM: an approach for connectivity and coverage maximization

The internet of Things (IoT) has attracted significant attention in many applications in both academic and industrial areas. In IoT, each object can have the capabilities of sensing, identifying, networking and processing to communicate with ubiquitous objects and services. Often this paradigm (IoT) using Wireless Sensor Networks must cover large area of interest (AoI) with huge number of devices. As these devices might be battery powered and randomly deployed, their long-term availability and connectivity for area coverage is very important, in particular in harsh environments. Moreover, a poor distribution of devices may lead to coverage holes and degradation to the quality of service. In this paper, we propose an approach for self-organization and coverage maximization. We present a distributed algorithm for “Maintaining Connectivity and Coverage Maximization” called MCCM . The algorithm operates on different movable devices in homogeneous and heterogeneous distribution. It does not require high computational complexity. The main goal is to keep the movement of devices as minimal as possible to save energy. Another goal is to reduce the overlapping areas covered by different devices to increase the coverage while maintaining connectivity. Simulation results show that the proposed algorithm can achieve higher coverage and lower nodes’ movement over existing algorithms in the state of the art