69 research outputs found

    Honeypot for Wireless Sensor Networks

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    People have understood that computer systems need safeguarding and require knowledge of security principles for their protection. While this has led to solutions for system components such as malware-protection, firewalls and intrusion detection systems, the ubiquitous usage of tiny microcomputers appeared at the same time. A new interconnectivity is on the rise in our lives. Things become “smart” and increasingly build new networks of devices. In this context the wireless sensor networks here interact with users and also, vice versa as well; unprivileged users able to interact with the wireless sensor network may harm the privileged user as a result. The problem that needs to be solved consists of possible harm that may be caused by an unprivileged user interacting with the wireless sensor network of a privileged user and may come via an attack vector targeting a vul- nerability that may take as long as it is needed and the detection of such mal-behaviour can only be done if a sensing component is implemented as a kind of tool detecting the status of the attacked wireless sensor network component and monitors this problem happening as an event that needs to be researched further on. Innovation in attack detection comprehension is the key aspect of this work, because it was found to be a set of hitherto not combined aspects, mechanisms, drafts and sketches, lacking a central combined outcome. Therefore the contribution of this thesis consists in a span of topics starting with a summary of attacks, possible countermeasures and a sketch of the outcome to the design and implementation of a viable product, concluding in an outlook at possible further work. The chosen path for the work in this research was experimental prototype construction following an established research method that first highlights the analysis of attack vectors to the system component and then evaluates the possibilities in order to im- prove said method. This led to a concept well known in common large-scale computer science systems, called a honeypot. Its common definitions and setups were analy- sed and the concept translation to the wireless sensor network domain was evaluated. Then the prototype was designed and implemented. This was done by following the ap- proach set by the science of cybersecurity, which states that the results of experiments and prototypes lead to improving knowledge intentionally for re-use

    Optimisation de réseaux de capteurs sans fil pour le suivi de cibles mobiles

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    Wireless sensor networks have received a particular attention during the last years, involving many applications, such as vehicle tracking or battlefield monitoring.A set of sensors is randomly dispatched in a region in order to monitor moving targets.Each sensor has a limited battery lifetime and two states: active or inactive.An active sensor is able to monitor targets inside its sensing radius, which consumes energy.In this thesis, the studied problems consist in deciding an optimal schedule of sensing activities, in order to cover all the targets at any instant of the mission.First, we study a robust scheduling problem.A target such that the spatial trajectory is exactly known is subject to temporal uncertainties.This context is met for a plane flying in an airline route, a train running on a railway, or any vehicle following a predetermined path.The objective is to compute a schedule of activities able to resist to the largest uncertainties.This first problem is solved using an exact pseudo-polynomial algorithm, relying on a dichotomy.Second, we study a problem aiming at preserving enough sensor network capacity in order to perform further missions.For this problem, the targets are subject to spatial uncertainties, i.e. their actual position may be at a distance ÎŽ\delta of their expected position.This second problem is solved using an exact algorithm based on column generation, accelerated by a metaheuristic.All the proposed methods have a common phase, called discretization, that leads to reformulate the original problems as activity scheduling problems.The monitored area is split into faces, that are defined as sets of points covered by the same set of sensors.Computing the stay duration of targets inside each face leads to split the mission duration into time windows, so the moving target tracking problem can be seen as a sequence of static target tracking problems.The proposed algorithms are tested on many instances, and the analysis of the results is provided.Numerous open perspectives of this work are also given.Les rĂ©seaux de capteurs sans fil suscitent une attention croissante depuis quelques annĂ©es, tant les applications sont nombreuses, incluant notamment le suivi de vĂ©hicules ou la surveillance de champs de bataille.Un ensemble de capteurs dissĂ©minĂ© alĂ©atoirement a pour but de surveiller des cibles se dĂ©plaçant dans une rĂ©gion donnĂ©e.Chaque capteur a une durĂ©e de vie limitĂ©e et deux Ă©tats : actif ou inactif.Un capteur actif peut surveiller des cibles dans son rayon de portĂ©e, au prix d'une consommation d'Ă©nergie.Dans cette thĂšse, les problĂšmes Ă©tudiĂ©s consistent Ă  dĂ©terminer un ordonnancement optimal d'activitĂ©s de surveillance, afin de couvrir toutes les cibles Ă  tout instant de la mission.Nous abordons en premier lieu un problĂšme d'ordonnancement robuste.Une cible dont on connaĂźt la trajectoire spatiale avec prĂ©cision est sujette Ă  incertitude temporelle.Cette situation est rencontrĂ©e lorsqu'un avion vole dans un couloir aĂ©rien, qu'un train circule sur une voie ferrĂ©e, ou que de tout autre vĂ©hicule suit un itinĂ©raire prĂ©-dĂ©terminĂ©.L'objectif est de calculer un ordonnancement d'activitĂ©s capable de rĂ©sister au plus grand Ă©cart par rapport aux dates prĂ©visionnelles de passage de la cible.Ce premier problĂšme est rĂ©solu Ă  l'aide d'un algorithme exact pseudo-polynomial, reposant sur une dichotomie.En second lieu, nous Ă©tudions le problĂšme visant Ă  prĂ©server la capacitĂ© de surveillance du rĂ©seau de capteurs dans un contexte multi-missions.Les cibles sont maintenant sujettes Ă  une incertitude spatiale, c'est-Ă -dire susceptibles de se trouver Ă  une distance infĂ©rieure Ă  un seuil ÎŽ\delta de leur position prĂ©visionnelle.Ce second problĂšme est rĂ©solu Ă  l’aide d’un algorithme exact basĂ© sur la gĂ©nĂ©ration de colonnes, et accĂ©lĂ©rĂ© par une mĂ©taheuristique.Les mĂ©thodes de rĂ©solution proposĂ©es ont en commun une Ă©tape prĂ©liminaire, appelĂ©e discrĂ©tisation, qui conduit Ă  reformuler les problĂšmes originaux comme des problĂšmes d'ordonnancement d'activitĂ©s de surveillance.L'espace de surveillance est dĂ©coupĂ© en faces, ensembles de points couverts par un mĂȘme sous-ensemble de capteurs.Le calcul des durĂ©es de sĂ©jour des cibles dans chaque face permet de dĂ©couper la durĂ©e de la mission en fenĂȘtres de temps, et d'envisager le problĂšme de couverture de cibles mobiles comme une sĂ©quence de problĂšmes de couverture de cibles immobiles.Les algorithmes proposĂ©s pour aborder ces problĂšmes sont testĂ©s sur de nombreuses instances, et leurs rĂ©sultats sont analysĂ©s.De nombreuses perspectives ouvertes par ces travaux sont Ă©galement prĂ©sentĂ©es

    Software Defined Applications in Cellular and Optical Networks

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    abstract: Small wireless cells have the potential to overcome bottlenecks in wireless access through the sharing of spectrum resources. A novel access backhaul network architecture based on a Smart Gateway (Sm-GW) between the small cell base stations, e.g., LTE eNBs, and the conventional backhaul gateways, e.g., LTE Servicing/Packet Gateways (S/P-GWs) has been introduced to address the bottleneck. The Sm-GW flexibly schedules uplink transmissions for the eNBs. Based on software defined networking (SDN) a management mechanism that allows multiple operator to flexibly inter-operate via multiple Sm-GWs with a multitude of small cells has been proposed. This dissertation also comprehensively survey the studies that examine the SDN paradigm in optical networks. Along with the PHY functional split improvements, the performance of Distributed Converged Cable Access Platform (DCCAP) in the cable architectures especially for the Remote-PHY and Remote-MACPHY nodes has been evaluated. In the PHY functional split, in addition to the re-use of infrastructure with a common FFT module for multiple technologies, a novel cross functional split interaction to cache the repetitive QAM symbols across time at the remote node to reduce the transmission rate requirement of the fronthaul link has been proposed.Dissertation/ThesisDoctoral Dissertation Electrical Engineering 201

    Design and optimization of optical grids and clouds

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    Design of interface selection protocols for multi-homed wireless networks

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    The IEEE 802.11/802.16 standards conformant wireless communication stations have multi-homing transmission capability. To achieve greater communication efficiency, multi-homing capable stations use handover mechanism to select appropriate transmission channel according to variations in the channel quality. This thesis presents three internal-linked handover schemes, (1) Interface Selection Protocol (ISP), belonging to Wireless Local Area Network (WLAN)- Worldwide Interoperability for Microwave Access (WiMAX) environment (2) Fast Channel Scanning (FCS) and (3) Traffic Manager (TM), (2) and (3) belonging to WiMAX Environment. The proposed schemes in this thesis use a novel mechanism of providing a reliable communication route. This solution is based on a cross-layer communication framework, where the interface selection module uses various network related parameters from Medium Access Control (MAC) sub-layer/Physical Layer (PHY) across the protocol suite for decision making at the Network layer. The proposed solutions are highly responsive when compared with existing multi-homed schemes; responsiveness is one of the key factors in the design of such protocols. Selected route under these schemes is based on the most up to date link-layer information. Therefore, such a route is not only reliable in terms of route optimization but it also fulfils the application demands in terms of throughput and delay. Design of ISP protocol use probing frames during the route discovery process. The 802.11 mandates the use of different rates for data transmission frames. The ISP-metric can be incorporated into various routing aspects and its applicability is determined by the possibility of provision of MAC dependent parameters that are used to determine the best path metric values. In many cases, higher device density, interference and mobility cause variable medium access delays. It causes creation of ‘unreachable zones’, where destination is marked as unreachable. However, by use of the best path metric, the destination has been made reachable, anytime and anywhere, because of the intelligent use of the probing frames and interface selection algorithm implemented. The IEEE 802.16e introduces several MAC level queues for different access categories, maintaining service requirement within these queues; which imply that frames from a higher priority queue, i.e. video frames, are serviced more frequently than those belonging to lower priority queues. Such an enhancement at the MAC sub-layer introduces uneven queuing delays. Conventional routing protocols are unaware of such MAC specific constraints and as a result, these factors are not considered which result in channel performance degradation. To meet such challenges, the thesis presents FCS and TM schemes for WiMAX. For FCS, Its solution is to improve the mobile WiMAX handover and address the scanning latency. Since minimum scanning time is the most important issue in the handover process. This handover scheme aims to utilize the channel efficiently and apply such a procedure to reduce the time it takes to scan the neighboring access stations. TM uses MAC and physical layer (PHY) specific information in the interface metric and maintains a separate path to destination by applying an alternative interface operation. Simulation tests and comparisons with existing multi-homed protocols and handover schemes demonstrate the effectiveness of incorporating the medium dependent parameters. Moreover, show that suggested schemes, have shown better performance in terms of end-to-end delay and throughput, with efficiency up to 40% in specific test scenarios.EThOS - Electronic Theses Online ServiceGBUnited Kingdo
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