Adding Network Coding Capabilities to the WSNet Simulator

This technical report presents the implementation of a Network Coding module in WSNet - a Wireless Sensor Network simulator. This implementation provides a generic programming interface to allow an easy specialization of different coding strategies: random, source/destination-oriented, intra/inter-flow, etc

Multi-mode relaying for energy consumption reduction

Today mobile terminals offer today the possibility of switching between different physical layers of radio protocols. With a generalization of Software Defined Radio, this multi-mode property improves the connectivity but has an important cost in terms of energy consumption. In this paper, we study the possibility of reducing energy consumption by using a relay on possibly different communication modes. We show that a multi-mode relay, compared to simple (mono-mode) relay, has an impact on energy consumption. We propose an analytical study of energy consumption in multi-mode terminals. Then, we will compare the network energy consumption following two scenarios: in the first one, a mobile terminal relays other users, in the second one terminals connect directly to an Access Point. We evaluate the consumption of the terminals in an 802.11g-to-UMTS and an 802.15.4-to-802.11g relay scheme. We isolate rules to minimize the network global energy consumption through multi-mode relaying. We show that the most intuitive solution is not always the best one and that a very precise simulation is necessary to make good choices at run time.Aujourd'hui, les terminaux mobiles permettent de choisir parmi différentes couches physiques de protocoles radios. Avec la généralisation de la Radio Logicielle, cette propriété multi-mode améliore la connectivité, mais rajoute un important surcoût à la consommation d'énergie. Dans ce papier, nous étudions la possibilité de réduire la consommation d'énergie en proposant un relais peut communiquer sur ces différents modes. Nous montrons qu'un relais multi-mode a un impact sur la consommation d'énergie, en comparaison à un simple relais mono-mode. Nous proposons une étude analytique de la consommation d'énergie pour les terminaux multi-modes. Puis, nous comparons la comsommation d'énergie du réseau suivant deux scénarios: dans le premier, un terminal mobile joue le rôle de relais pour d'autres utilisateurs ; dans le second, tous les terminaux se connectent directement au point d'accès. Nous évaluons la consommation des terminaux dans des scénarios de relais 802.11g-vers-UMTS et 802.15.4-vers-802.11g. Nous isolons des règles qui permettent de minimiser la consommation global du réseau au travers des relais multi-modes. Nous montrons que la solution la plus intuitive n'est pas toujours la meilleure, et qu'une évaluation précise au travers de simulations est nécessaire afin de procéder à un bon choix de paramètres

A Cross-layer Framework for Multiobjective Performance Evaluation of Wireless Ad Hoc Networks

International audienceIn this paper we address the problem of finding the optimal performance region of a wireless ad hoc network when multiple performance metrics are considered. Our contribution is to propose a novel cross-layer framework for deriving the Pareto optimal performance bounds for the network. These Pareto bounds provide key information for understanding the network behavior and the performance trade-offs when multiple criteria are relevant. Our approach is to take a holistic view of the network that captures the cross-interactions among interference management techniques implemented at various layers of the protocol stack (e.g. routing and resource allocation) and determines the objective functions for the multiple criteria to be optimized. The resulting complex multiobjective optimization problem is then solved by multiobjective search techniques. The Pareto optimal sets for an example sensor network are presented and analyzed when delay, reliability and energy objectives are considered

Load balancing and context aware enhancements for RPL routed Internet of Things.

Internet of Things (IoT) has been paving the way for a plethora of potential applications, which becomes more spatial and demanding. The goal of this work is to optimise the performance within the IPv6 Routing Protocol for Low-Power and Lossy Networks (RPL) in the network layer.RPL still suffers from unbalanced load traffic among the candidate parents. Consequently, the overloaded parent node drains its energy much faster than other candidate parent nodes. This may lead to an early disconnection of a part of the network topology and affect the overall network reliability. To solve this problem, a new objective function (OF) has been proposed to usher better load balancing among the bottleneck candidate parents, and keep the overloaded nodes lifetime thriving to longer survival.Moreover, several IoT applications have antagonistic requirements but pertinent, which results in a greater risk of affecting the network reliability, especially within the emergency scenarios. With the presence of this challenging issue, the current standardised RPL OFs cannot sufficiently fulfil the antagonistic needs of Low-power and Lossy Networks (LLNs) applications. In response to the above issues, a context adaptive OF has been proposed to facilitate exchanging the synergy information between the application and network layers. Thus, the impact of the antagonistic requirements based on context parameters will be mitigated via rationalizing the selection decision of the routing path towards the root node.We implemented the proposed protocol and verified all our findings through excessive measurements via simulations and a realistic deployment using a real testbed of a multi-hop LLNs motes. The results proved the superiority of our solution over the existing ones with respect to end-to-end delay, packet delivery ratio and network lifetime. Our contribution has been accepted initially to be adopted within the standard body Internet Engineering Task Force (IETF)

Virtual innovation lab

Dissertação de mestrado em Engenharia e Gestão de Sistemas de InformaçãoO tema que se propõe estudar é a maneira como as pequenas e médias empresas (PMEs) podem aprender sobre o potencial transformador das tecnologias emergentes, adquirindo uma melhor preparação para a Transformação Digital de produtos/serviços, processos e modelos de negócio. As PMEs têm maior dificuldade em avaliar o potencial transformador das tecnologias emergentes. Esta dificuldade advém da complexidade destas tecnologias, as quais estão frequentemente em estado muito imaturo de desenvolvimento. Assim a experimentação com estas tecnologias num ambiente seguro torna-se fundamental para uma decisão de investimento bem fundamentada. O primeiro objetivo deste trabalho é explorar os desafios da transformação digital com os quais os gestores das PMEs se defrontam, em particular o desafio de compreender o potencial transformador das tecnologias emergentes. Este trabalho parte do pressuposto que a aprendizagem por simulação é um meio eficaz para atingir esta compreensão. Neste trabalho apresentamos uma visão geral sobre como a simulação tem vindo a ser aplicada para promover a aprendizagem de processos e tecnologias complexas, nomeadamente em áreas como enfermagem e aviação. A experiência relatada nestas áreas é importante para informar a utilização da simulação na área dos Sistemas de Informação bem como fundamentar as decisões deste trabalho. Assim, o nosso trabalho foca três áreas centrais: (1) a implementação de estratégias de transformação digital nas PMEs, (2) as tecnologias emergentes com potencial transformador dos modelos de negócio das PMEs, e (3) a aprendizagem baseada na simulação da utilização de tecnologias emergentes. O nosso trabalho fornece recomendações para o desenvolvimento de competências digitais avançadas nas PMEs e apresenta um ambiente virtual de apoio à transformação digital nestas empresas. As recomendações e ambiente virtual são úteis aos gestores das PMEs e apontam caminhos para futura investigação na área da aprendizagem por simulação no contexto da transformação digital das PMEs.The theme we propose to study is the way in which small and medium-sized companies (SMEs) can learn about the transformative potential of emerging technologies, acquiring a better preparation for the Digital Transformation of products/services, processes and business models. SMEs find it more difficult to assess the transformative potential of emerging technologies. This difficulty come from the complexity of these technologies, which are often in a very immature state of development. Thus, experimentation with these technologies in a safe environment becomes essential for a well-founded investment decision. The first objective of this work is to explore the challenges of digital transformation that SME managers face, in particular the challenge of understanding the transformative potential of emerging technologies. This work assumes that simulation learning is an effective way to achieve this understanding. In this work we present an overview of how simulation has been applied to promote the learning of complex processes and technologies, namely in areas such as nursing and aviation. The experience reported in these areas is important to inform the use of simulation in the area of Information Systems as well as to base the decisions of this work. Thus, our work focuses on three central areas: (1) the implementation of digital transformation strategies in SMEs, (2) the emerging technologies with the transforming potential of SME business models, and (3) learning based on the simulation of use emerging technologies. Our work provides recommendations for the development of advanced digital skills in SMEs and presents a virtual environment to support digital transformation in these companies. The recommendations and virtual environment are useful to SME managers and point out ways for future research in the area of learning by simulation in the context of the digital transformation of SMEs

Next-Generation Public Safety Systems Based on Autonomous Vehicles and Opportunistic Communications

An emergency scenario is characterized by the unpredictability of the environment conditions and by the scarcity of the available communication infrastructures. After a natural or human disaster, the main public and private infrastructures are partially damaged or totally destroyed. These infrastructures include roads, bridges, water supplies, electrical grids, telecommunications and so on. In these conditions, the first rescue operations executed by the public safety organizations can be very difficult, due to the unpredictability of the disaster area environment and the lack in the communications systems. The aim of this work is to introduce next-generation public safety systems where the main focus is the use of unmanned vehicles that are able to exploit the self-organizing characteristics of such autonomous systems. With the proposed public safety systems, a team of autonomous vehicles will be able to overcome the hazardous environments of a post disaster scenario by introducing a temporary dynamic network infrastructure which enables the first responders to cooperate and to communicate with the victims involved. Furthermore, given the pervasive penetration of smart end-user devices, the emergence of spontaneous networks could constitute promising solutions to implement emergency communication systems. With these systems the survivors will be able to self-organize in a communication network that allows them to send alerts and information messages towards the rescue teams, even in absence of communication infrastructures

Wireless Sensor Networks

The aim of this book is to present few important issues of WSNs, from the application, design and technology points of view. The book highlights power efficient design issues related to wireless sensor networks, the existing WSN applications, and discusses the research efforts being undertaken in this field which put the reader in good pace to be able to understand more advanced research and make a contribution in this field for themselves. It is believed that this book serves as a comprehensive reference for graduate and undergraduate senior students who seek to learn latest development in wireless sensor networks

A distributed data extraction and visualisation service for wireless sensor networks

With the increase in applications of wireless sensor networks, data extraction and visualisation have become a key issue to develop and operate these networks. Wireless sensor networks typically gather data at a discrete number of locations. By bestowing the ability to predict inter-node values upon the network, it is proposed that it will become possible to build applications that are unaware of the concrete reality of sparse data. The aim of this thesis is to develop a service for maximising information return from large scale wireless sensor networks. This aim will be achieved through the development of a distributed information extraction and visualisation service called the mapping service. In the distributed mapping service, groups of network nodes cooperate to produce local maps which are cached and merged at a sink node, producing a map of the global network. Such a service would greatly simplify the production of higher-level information-rich representations suitable for informing other network services and the delivery of field information visualisations. The proposed distributed mapping service utilises a blend of both inductive and deductive models to successfully map sense data and the universal physical principles. It utilises the special characteristics of the application domain to render visualisations in a map format that are a precise reflection of the concrete reality. This service is suitable for visualising an arbitrary number of sense modalities. It is capable of visualising from multiple independent types of the sense data to overcome the limitations of generating visualisations from a single type of a sense modality. Furthermore, the proposed mapping service responds to changes in the environmental conditions that may impact the visualisation performance by continuously updating the application domain model in a distributed manner. Finally, a newdistributed self-adaptation algorithm, Virtual Congress Algorithm,which is based on the concept of virtual congress is proposed, with the goal of saving more power and generating more accurate data visualisation.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Optimization-Based Methodology for the Exploration of Cyber-Physical System Architectures

In this thesis, we address the design space exploration of cyber-physical system architectures to select correct-by-construction configuration and interconnection of system components taken from pre-defined libraries. We formulate the exploration problem as a mapping problem and use optimization to solve it by searching for a minimum cost architecture that meets system requirements. Using a graph-based representation of a system architecture, we define a set of generic mixed integer linear constraints over graph vertices, edges and paths, and use these constraints to instantiate a variety of design requirements (e.g., interconnection, flow, workload, timing, reliability, routing). We implement a comprehensive toolbox that supports all steps of the proposed methodology. It provides a pattern-based formal language to facilitate requirements specification and a set of scalable algorithms for encoding and solving exploration problems. We prove our concepts on a set of case studies for different cyber-physical system domains, such as electrical power distribution networks, reconfigurable industrial production lines and wireless sensor networks