Teses / dissertações sobre o tema "Chiffrement basé sur les réseaux"
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Siad, Amar. "Protocoles de génération des clés pour le chiffrement basé sur de l'identité". Paris 8, 2012. http://www.theses.fr/2012PA083660.
Texto completo da fonteIdentity-Based Encryption suffers from the problem of trust in the key generation authority PKG (Private Key Generator), which results in the ability of this authority to produce and distribute, without the knowledge a genuine user, multiple private-keys or multiple copies of a single key. This problem makes the deployment of these systems limited to areas where trust in the PKG must have a fairly high level. An important and natural question is to ask how can we reduce the trust one should have in the PKG. In this thesis, after conducting a development of the state of the art on the subject, we answer this question by studying this problem in its theoretical and practical aspects. On the theoretical stage, we present constructions of distributed cryptographic protocols that reduce the trust to its lowest level never reached before. We develop protocols for private-key generation in different security models while presenting real-world applications using these new protocols in the setting of searchable encryption. Furthermore, we develop necessary infrastructures needed for the deployment of our protocols. In practical terms, we implement KGLib: the first complete, efficient and modular library which brings together the most known techniques for private-key generation for identity-based cryptosystems. This library aims at providing robust tools designed in a modular and reusable way to allow easy implementation and rapid prototyping of the latest results coming from theoretical cryptography
Chinthamani, Dwarakanath Nagarjun. "Theoretical and practical contributions to homomorphic encryption". Electronic Thesis or Diss., université Paris-Saclay, 2021. http://www.theses.fr/2021UPASG103.
Texto completo da fonteIn conventional encryption schemes, the primary aim of the scheme is to ensure confidentiality of the data. Fully Homomorphic Encryption (FHE), a variant first realized by Gentry, is an encryption scheme which also allows for computation over the encrypted data, without ever needing to decrypt it. Using this, any untrusted third party with the relevant key material can perform homomorphic computations, leading to many applications where an untrusted party can still be allowed to compute over encryptions of sensitive data (cloud computing), or where the trust needs to be decentralized (multi-party computation).This thesis consists of two main contributions to Fully Homomorphic Encryption. In the first part, we take an FHE based on Fermat numbers and extend it to work with multi-bit numbers. We also add the ability to homomorphically evaluate small functions, with which we can compute additions and multiplication with only a few bootstrappings, and these can be used as building blocks for larger computations. Some newer results on sub-Gaussian random variables are adapted to give a better error analysis.One of the obstacles in bringing FHE to the mainstream remains its large computational complexity, and optimized architectures to accelerate FHE computations on reconfigurable hardware have been proposed. The second part of our thesis proposes an architecture for the polynomial arithmetic used in FV-like cryptosystems. This can be used to compute the sum and product of ring polynomials, using a pair of NTT algorithms which avoids the use of bit reversal, and subsumes the need for multiplication by weight vectors. For the cost of storing twiddle factors in a ROM, we avoid twiddle updates leading to a much smaller cycle count
Laganier, Julien. "Architecture de sécurité décentralisée basée sur l'identification cryptographique". Lyon, École normale supérieure (sciences), 2005. http://www.theses.fr/2005ENSL0354.
Texto completo da fonteThis thesis studies the problem of securing large scale and dynamic communication, execution and storage infrastructures. The majority of existing security solutions relies on the existence of a global public key infrastructure. The deployment of such a global infrastructure is problematic at technical, administrative and political levels. In order to relieve solutions from this constraint, we propose a decentralized security approach based on cryptographic identifiers (CBID, CGA, HBA and HIP) and delegation (SPKI certificates). We show that this security approach fits better to the intrinsical decentralized nature of the large scale, shared and open systems like Internet or grid computing. To validate the approach, we instantiate it into several security solutions for existing protocols using the IP security (IPsec) and host identity (HIP) protocols. In particular, security solutions for the IPv6 (Internet Protocol version 6) network layer and its ND (Neighbor Discovery) component, as well as for virtualization of the execution, communication and storage infrastructure of grid computing (Supernet, HIPernet and Internet Backplane Protocol) are presented and analysed
Ricosset, Thomas. "Signature électronique basée sur les réseaux euclidiens et échantillonnage selon une loi normale discrète". Thesis, Toulouse, INPT, 2018. http://www.theses.fr/2018INPT0106/document.
Texto completo da fonteLattice-based cryptography has generated considerable interest in the last two decades due toattractive features, including conjectured security against quantum attacks, strong securityguarantees from worst-case hardness assumptions and constructions of fully homomorphicencryption schemes. On the other hand, even though it is a crucial part of many lattice-basedschemes, Gaussian sampling is still lagging and continues to limit the effectiveness of this newcryptography. The first goal of this thesis is to improve the efficiency of Gaussian sampling forlattice-based hash-and-sign signature schemes. We propose a non-centered algorithm, with aflexible time-memory tradeoff, as fast as its centered variant for practicable size of precomputedtables. We also use the Rényi divergence to bound the precision requirement to the standarddouble precision. Our second objective is to construct Falcon, a new hash-and-sign signaturescheme, based on the theoretical framework of Gentry, Peikert and Vaikuntanathan for latticebasedsignatures. We instantiate that framework over NTRU lattices with a new trapdoor sampler
Prest, Thomas. "Gaussian sampling in lattice-based cryptography". Thesis, Paris, Ecole normale supérieure, 2015. http://www.theses.fr/2015ENSU0045/document.
Texto completo da fonteAlthough rather recent, lattice-based cryptography has stood out on numerous points, be it by the variety of constructions that it allows, by its expected resistance to quantum computers, of by its efficiency when instantiated on some classes of lattices. One of the most powerful tools of lattice-based cryptography is Gaussian sampling. At a high level, it allows to prove the knowledge of a particular lattice basis without disclosing any information about this basis. It allows to realize a wide array of cryptosystems. Somewhat surprisingly, few practical instantiations of such schemes are realized, and the algorithms which perform Gaussian sampling are seldom studied. The goal of this thesis is to fill the gap between the theory and practice of Gaussian sampling. First, we study and improve the existing algorithms, byboth a statistical analysis and a geometrical approach. We then exploit the structures underlying many classes of lattices and apply the ideas of the fast Fourier transform to a Gaussian sampler, allowing us to reach a quasilinearcomplexity instead of quadratic. Finally, we use Gaussian sampling in practice to instantiate a signature scheme and an identity-based encryption scheme. The first one yields signatures that are the most compact currently obtained in lattice-based cryptography, and the second one allows encryption and decryption that are about one thousand times faster than those obtained with a pairing-based counterpart on elliptic curves
Garcia, Emmanuel. "Tatouage d'objets 3D basé sur la texture". Nice, 2004. http://www.theses.fr/2004NICE4025.
Texto completo da fonteThe goal of all current 3D object watermarking algorithms is to protect either the computer data representing an object's geometry or the intrinsic shape of a 3D object. Observing that these methods cannot protect the use of 3D objects in terms of visual representation, we propose a completely different approach, based on the texture of 3D objects. The idea is to watermark the texture of a 3D object and then be able to retrieve the watermark from any 2D representation of the object. This method works by reconstructing the object's texture from a given 2D view of it. For this, the rendering parameters must be known or estimated. After evaluating our algorithm in a controlled environment we thus propose a projective registration algorithm allowing us to accurately estimate the perspective projection used to produce a given 2D view. The last part of this thesis presents an algorithm for hiding the geometry of a 3D object into its texture image. The originality of this data-hiding algorithm is that the hidden information is intimately linked to the host information. We want to preserve this link of spatial coherence as well as ensure that the retrieved data degrades progressively when the host information is degraded. This is achieved through a spatio-frequential representation of geometry and texture, which are both represented as a function of cylindrical coordinates
Brini, Asma Hedia. "Un modèle de recherche d'information basé sur les réseaux possibilistes". Toulouse 3, 2005. http://www.theses.fr/2005TOU30224.
Texto completo da fonteWe propose an approach to Information Retrieval (IR) where relevance is flexible. The model is based on possibilistic networks where documents, index terms and query are binary variables and arcs are quantified in the theory of possibility framework. This model should provide proposition like : (i) it is plausible to a certain degree that the document is relevant ; (ii) it is necessary that the document is relevant given the query. The first kind of answer is meant to eliminate irrelevant documents (weak plausibility). The second answer focuses attention on what looks very relevant. Besides, we proposed three new discriminant factors that penalise documents not containing query important terms. These factors can be adaptable to any existing models. The results obtained show the effectiveness of our approach
Aussibal, Julien. "Rsids : un IDS distribué basé sur le framework CVSS". Pau, 2009. http://www.theses.fr/2009PAUU3044.
Texto completo da fonteIntrusion detection is a method that ensures the availability concept in systems and computer networks. This availability is generally undermined by various anomalies. These anomalies can be caused either legitimately unintended result has operations working on these systems (broken link, traffic, or. . . ), so illegitimate with malicious operations designed to undermine the availability of these systems. The implementation of these various anomalies detection tools, such as IDS (Intrusion Detection System), contribute to early identification of these anomalies and to block them. This thesis has enabled us to develop a new generation platform to generate legitimate and illegitimate anomalies. This work was carried out under the project METROSEC. This platform has enabled us to obtain various traffic captures containing these anomalies. The various illegimitate anomalies were performed with classic tools to make Denial of Service like TFN2k or Trinoo. Legitimate Anormalies were also conducted with flash crowd phenomenon. All these catch real traffic were used in further research on intrusion detection for the evaluation of new methods of detection. In a second part, the implementation of a new detection tool seems necessary to improve the quality of detection of these anomalies. This new distributed IDS, called RSIDS (Risk Scored Intrusion Detection System), will retrieve the results of a multitude of heterogeneous probes. The use of probes will remove the risk of false alarms. Indeed, a probe is not able to detect all anomalies that occur on a system or network. Each alert provided by its probes will be evaluated according to their degree of dangerousness. The assessment of dangerousness based on the framework CVSS (Common Vulnerability Scoring System)
Royer, Mickaël. "Routage basé sur le contenu dans les réseaux ad-hoc aéronautiques". Thesis, Toulouse 3, 2016. http://www.theses.fr/2016TOU30047/document.
Texto completo da fonteIn a context of growing needs of communication means to increase ight safety and meet the expectations of companies and passengers, the world of civil aviation seeks new communication systems that can meet these objectives. The Aeronautical Ad-Hoc Networks, AANETs represent an innovative approach to address this problem. It is self-configured networks, using no fixed infrastructure where the nodes are commercial aircraft. The AANETs can be seen as a subset of the VANET (Vehicular Ad-Hoc Networks) since they share many features as the constraints imposed on the trajectories. In order to use these mobile networks more eficiently while meeting the needs of new applications, such as the transmission of weather information in real time, requiring air to air communications. , we propose in this thesis to use the paradigm of content based routing above AANET. In this kind of routing, it is not a destination address that is used to identify the recipients, but the message content itself. In this paradigm, a transmitter sends a message having attributes and the message is then transmitted by the network to nodes interested by the content of the message. Applied to weather information update, this approach allows an aircraft detecting a dangerous phenomenon such as a thunderstorm to only prevent interested nodes, ie those whose the trajectorycome close to the storm during the lifetime of the event. In this thesis, we have chosen to rely on the popular Publish / Subscribe (P/S) paradigm to provide a content based routing service. In this approach, publishers publish events. On the other side, nodes send subscriptions to declare their interest and the system is then in charge of forward events to nodes that match their needs. After a state of the art about existing P / S systems, particularly those adapted to VANETs, we choose to test the solutions seemed interesting in a AANET context. To accomplish this, we have developed as a Omnet ++ mobility model using real position reports to replay a full day of trafic of aircraft and several aeronautical applications based on a P / S system to generate realistic data. The results show that these solutions are not completely suitable for AANET context. Therefore, in a second step, we proposed a new P / S system which is more eficient on a AANET. This solution is based on an overlay network built thanks to a new of 1-hopping clustering algorithm suitable for AANET. In order to increase the stability of the overlay architecture, this algorithm is based on the number of neighbors and the relative mobility between the nodes to define groups. The tests show that the P/S system based on this overlay provides better results than the previously tested solutions, whether in terms of network load or percentage of transmitted events
Frainay, Clément. "Système de recommandation basé sur les réseaux pour l'interprétation de résultats de métabolomique". Thesis, Toulouse 3, 2017. http://www.theses.fr/2017TOU30297/document.
Texto completo da fonteMetabolomics allows large-scale studies of the metabolic profile of an individual, which is representative of its physiological state. Metabolic markers characterising a given condition can be obtained through the comparison of those profiles. Therefore, metabolomics reveals a great potential for the diagnosis as well as the comprehension of mechanisms behind metabolic dysregulations, and to a certain extent the identification of therapeutic targets. However, in order to raise new hypotheses, those applications need to put metabolomics results in the light of global metabolism knowledge. This contextualisation of the results can rely on metabolic networks, which gather all biochemical transformations that can be performed by an organism. The major bottleneck preventing this interpretation stems from the fact that, currently, no single metabolomic approach allows monitoring all metabolites, thus leading to a partial representation of the metabolome. Furthermore, in the context of human health related experiments, metabolomics is usually performed on bio-fluid samples. Consequently, those approaches focus on the footprints left by impacted mechanisms rather than the mechanisms themselves. This thesis proposes a new approach to overcome those limitations, through the suggestion of relevant metabolites, which could fill the gaps in a metabolomics signature. This method is inspired by recommender systems used for several on-line activities, and more specifically the recommendation of users to follow on social networks. This approach has been used for the interpretation of the metabolic signature of the hepatic encephalopathy. It allows highlighting some relevant metabolites, closely related to the disease according to the literature, and led to a better comprehension of the impaired mechanisms and as a result the proposition of new hypothetical scenario. It also improved and enriched the original signature by guiding deeper investigation of the raw data, leading to the addition of missed compounds. Models and data characterisation, alongside technical developments presented in this thesis, can also offer generic frameworks and guidelines for metabolic networks topological analysis
Kanazy, Redouane. "Pronostic des événements de défaillance basé sur les réseaux de Petri Temporels labellisés". Thesis, Lyon, 2020. http://theses.insa-lyon.fr/publication/2020LYSEI132/these.pdf.
Texto completo da fonteThe deployment of decision-support tools increases agility efficiency while reducing the cost of maintaining proper operation. Accidental or intentional shutdowns have disastrous and costly consequences. The scientific community of discrete event systems (DES), has been interested in the cause-effect relationships between certain nominal and dysfunctional states, to propose solutions responding to this problem. Our work is part of the framework of a steering of a system subject to failure events (FE). We have developed a model-based prognostic approach, which predicts the earliest date of occurrence of an FE, allowing the operator to plan repair interventions on components before altering the proper functioning. We modeled the system using labeled temporal Petri nets (RdPTL), since the analysis of its behavioral model is based on the sequentiality and date of occurrence of events. We have represented these dynamics through modeling in a context of mode analysis, limited to 3 modes of operation (nominal, degraded and critical). From its accessibility graph, we have built a prognosticator, which allows us to identify all the sequences of events ending with an FE. We used the notion of parameterization of the system states i.e. the introduction of a clock and a system of clock inequation (SE) for each state of the system. The states obtained from the discretization of time are then grouped in a single state and the SE will determine the values of the clocks. The prognosis cannot always be guaranteed. We then established the prognosticability property, to distinguish the sequences that are prognosticable from those that are not. To validate our approach, we chose a battery cell as a benchmark and the INA tool to generate the accessibility graph
Grida, Ben Yahia Imen. "Mécanisme de gestion basé sur les principes de l'informatique autonome pour les services de la nouvelle génération". Evry, Institut national des télécommunications, 2008. http://www.theses.fr/2008TELE0012.
Texto completo da fonteVautherin, Jacques. "Un modèle algébrique, basé sur les réseaux de Petri, pour l'étude des systèmes parallèles". Paris 11, 1985. http://www.theses.fr/1985PA112219.
Texto completo da fonteWe present a method of formal specification for parallel systems which combines abstract data types theory and Petri nets (PN) theory. We also introduce some analysis tools for such specifications: we examine how the properties of the models of a specification are related to the properties of an ordinary underlying PN; also, by extending the usual concept of semi-flow for ordinary PN, we show how it is possible to compute on a specification some invariants of the behaviour of its models. Finally, we present, for some "regular" models, an extension of the structural characterization of vivacity already known for some ordinary PN (states machines, events graphs)
Künzle, Luis Allan. "Raisonnement temporel basé sur les réseaux de Petri pour les systèmes manipulant des ressources". Toulouse 3, 1997. http://www.theses.fr/1997TOU30150.
Texto completo da fonteMoussaoui, Omar. "Routage hiérarchique basé sur le clustering : garantie de QoS pour les applications multicast et réseaux de capteurs". Cergy-Pontoise, 2006. http://biblioweb.u-cergy.fr/theses/06CERG0300.pdf.
Texto completo da fonteAdvances in networks and computers have prompted the development of very vast and various fields of applications. This diversity leads the networks ta support various types of traffic and to provide services which must be at the same time generic and adaptive because properties of quality of service (QoS) differ from a type of application to another. For example, the multi-media and real-time applications require low end-ta-end delays, bandwidth guarantee and low drop rate, whereas prolonged network lifetime is the main requirement for many Wireless Sensor Networks (WSN) applications. However, these two types of applications are established against the problem of scalability. Accordingly, the hierarchical routing based on the clustering is an effective approach for solving this problem. Indeed, clustering-based approach allow to reduce the complexity of the routing on a large scale by the means of (i) the division of the network into differem clusters based on sorne criteria of QoS, and (ii) the management of the intra-cluster communications locally by the elected nodes as Cluster Heads (CHs). Since the requirements in QoS depend on the applications type, the clustering procedure must be adapted to fulfil the requiremems of each application type. Our work through this thesis is related ta the hierarchical routing protocol based on the clustering and its application in various environments to offer a good QoS to the multi-media real-time applications, and the WSN applications
Zerioul, Lounis. "Modélisation comportementale d'un réseau sur puce basé sur des interconnexions RF". Thesis, Cergy-Pontoise, 2015. http://www.theses.fr/2015CERG0776/document.
Texto completo da fonteThe development of multiprocessor systems integrated on chip (MPSoC) respondsto the growing need for intensive computation systems. However, the evolutionof their performances is hampered by their communication networks on chip(NoC) due to their energy consumption and delay. It is in this context that the wired RF network on chip (RFNoC) was emerged. In order to better manage and optimize the design of an RFNoC, it is necessary to develop a simulation platform adressing both analog and digital circuits.First, a time domaine simulation of an RFNoC with components whose modelsare ideal is used to optimize the allocation of the available spectrum resources. Where appropriate, we provide solutions to improve the quality of transmitted signal. Secondly, we have developed, in VHDL-AMS, behavioral and accurate models of all RFNoC components. The models of the low noise amplifier (LNA) and the mixer take into account the parameters for the amplification, nonlinearities, noise and bandwidth. The model of the local oscillator considers the conventional parameters, including its phase noise. Concerning the transmission line, an accurate frequency model, including the skin effect is adapted for time domaine simulations. Then, the impact of component parameters on RFNoC performances is evaluatedto anticipate constraints of the RFNoC design
Komarova, Maryna. "Authentification rapide et contrôle d'accès basé sur la confiance dans les réseaux sans fil hétérogène". Phd thesis, Télécom ParisTech, 2008. http://pastel.archives-ouvertes.fr/pastel-00003793.
Texto completo da fonteEiche, Antoine. "Ordonnancement temps réel pour architectures hétérogènes reconfigurables basé sur des structures de réseaux de neurones". Phd thesis, Université Rennes 1, 2012. http://tel.archives-ouvertes.fr/tel-00783893.
Texto completo da fonteLahlou, Omar. "Routage multi-chemin basé sur la fiabilité des routes dans les réseaux mobiles Ad Hoc". Mémoire, Université de Sherbrooke, 2005. http://savoirs.usherbrooke.ca/handle/11143/1286.
Texto completo da fonteKarbaschi, Golnaz. "Routage basé sur la qualité des liens dans des réseaux multi-sauts IEEE 802. 11". Paris 6, 2008. http://www.theses.fr/2008PA066055.
Texto completo da fonteRodrigues, de Araujo Ricardo. "Traitement spatio-temporel basé sur l'utilisation de bases orthonormales généralisées : application aux réseaux de paquets". Paris 11, 2003. http://www.theses.fr/2003PA112101.
Texto completo da fonteThe packet radio access is an interesting option for multimedia traffic in radio mobile networks. This technique allows a radio resource allocation based on the user's activity in such a way that the canal may be used in a multi-user mode. So, the MAC protocol plays a fundamental role in this context. The S-Aloha and R-Aloha protocols are the most popular schemes due to their simplicity. Nevertheless, they offer a poor spectral efficiency. The use of smart antennas is widely proposed as a way of increasing the spectral efficiency of these MAC protocols. Actually, several papers were dedicated to performance analysis of packet networks with smart antennas. However, most of then have focussed only on the systemic aspects in detriment of signal processing ones. In this work, we evaluate the advantage of using smart antennas in a packet network with S-Aloha and R-Aloha MAC. We focus on the channel and the array geometry influences over the network performances. In the packet networks, the signal processing must be accomplished within the packet transmission time slot. That is the why the algorithm complexity must be limited. In order to decrease the overall system complexity, we propose the use of generalized orthonormal basis for the space-time equalizers. This strategy allows an equalizer order reduction if the base poles are correctly chosen. In this thesis, we compare the proposed structure performance with the conventional FIR one. Our simulations show that the proposed strategy leads to an efficient equalizer order reduction
Komarova, Maryna. "Authentification rapide et contrôle d'accès basé sur la confiance dans les réseaux sans fil hétérogènes". Paris, ENST, 2008. http://pastel.archives-ouvertes.fr/pastel-00003793/fr/.
Texto completo da fonteIn this thesis, we study the current situation and trends in wireless technologies development. We discuss the problems related to security mechanisms specific to each technology, and in particular the possibilities for integration and interworking. We first study the possibility of authentication latency decreasing in a scenario where the network access authentication is decoupled from the service access authentication. An authorized user is granted network and service access as a result of a single authentication process that combines 802. 1X and PANA operations. Then we introduce the Fast re-Authentication Protocol (FAP) for inter-domain roaming, which aims to reduce the authentication delay for a mobile user in a visited administrative domain. The approach eliminates the need for communication between the target and the user's home networks for credentials verification. We develop the Fast re-Authentication Protocol by suggesting a ticket distribution scheme for inter-domain roaming. This method decreases the number of tickets sent and consequently the overhead and delay of the ticket acquisition phase of the protocol. Numerical results obtained from experiments on a test-bed and a series of simulations show that the proposed scheme enhances inter-domain handover parameters such as authentication latency and signalling cost. To improve the access control to network resources we propose the adjustable trust model. The purpose of this work is to provide the network with the opportunity to react to user behaviour. Users are motivated to gain higher trust because trusted users have access to a larger set of services with higher quality of service. Validation of the proposed trust-based access control method has been done via simulations. Finally, we discuss how the proposed solutions can be implemented in a single framework
Nguyen, Van-Lu. "Padre : un langage d'expérimentation de programmation parallèle et distribuée basé sur les réseaux de Petri". Paris 6, 1986. http://www.theses.fr/1986PA066594.
Texto completo da fonteEmeriau, Samuel. "Caractérisation des réseaux multi-sujets en IRMf : apport du clustering basé sur la connectivité fonctionnelle". Thesis, Reims, 2011. http://www.theses.fr/2011REIMS018/document.
Texto completo da fonteThe comprehension of cerebral operations is in constant evolution since the rise of the neurosciences.New methods of imagery made it possible to highlight an architecture of our brain in complex networks.The purpose of my work is to develop a method to find the most representative networks of a group of subjects in Functional MRI.In the first step, I developed a method to reduce the fMRI data size based on clustering. I introduced a new characterization of functional information by the profile of connectivity. This one makes it possible to reduce the variance induced by the noise present within the data of Functional MRI.Moreover this profile does not require a priori information on the data contrary to the traditional inferential methods.In the second step, I developed a method to identify common networks on a group of subjects while taking into account of spatial and functional inter-subjects variability. The networks obtained can then be characterized by their spatial organization but also by their inner connectivity links.This method also allows the comparison of the networks of various groups of subjects, making it possible to highlight the implications of different networks according to different stimulations or pathological states
Vidal, Martin. "Architecture systolique pour un algorithme basé sur les réseaux de neurones pour l'égalisation de canaux". Thèse, Université du Québec à Trois-Rivières, 1999. http://depot-e.uqtr.ca/3409/1/000662425.pdf.
Texto completo da fonteGhadi, Abderrahim. "Modèle hiérarchique de contrôle d'accès d'UNIX basé sur un graphe de rôles". Strasbourg, 2010. http://www.theses.fr/2010STRA6005.
Texto completo da fonteConcerning access control, can the following question be addressed : "Is the access control system decidable ?". In other words : is it true that starting from a safe state of protection, we can assume at any time that is no intrusion which will endanger our system ?. In order to answer this question, we propose to model the access control system in the form of a graph of roles. The roles, which represent the vertices of graph contain, according to the security-policy, certain number of privileges. Every privilege represents one or several access rights on a given object. We presented two methods of use of this graph : The first consists in using an algorithm, which we developed by basing itself on the algorithms of the theory of the graphs, permit to search all over the path of the graph in order to find illicit privilege transfer. The second consists in storing our graph in a directory LDAP, this which brings us to develop a new plan LDAP to represent our graph of roles
Moussa, Ali Abdellatif Karim. "Chiffrement authentifié sur FPGAs de la partie reconfigurable à la partie static". Electronic Thesis or Diss., Paris 6, 2014. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2014PA066660.pdf.
Texto completo da fonteCommunication systems need to access, store, manipulate, or communicate sensitive information. Therefore, cryptographic primitives such as hash functions and block ciphers are deployed to provide encryption and authentication. Recently, techniques have been invented to combine encryption and authentication into a single algorithm which is called Authenticated Encryption (AE). Combining these two security services in hardware produces better performance compared to two separated algorithms since authentication and encryption can share a part of the computation. Because of combining the programmability with the performance ofcustom hardware, FPGAs become more common as an implementation target for such algorithms. The first part of this thesis is devoted to efficient and high-speed FPGA-based architectures of AE algorithms, AES-GCM and AEGIS-128, in order to be used in the reconfigurable part of FPGAs to support security services of communication systems. Our focus on the state of the art leads to the introduction of high-speed architectures for slow changing keys applications like Virtual Private Networks (VPNs). Furthermore, we present an efficient method for implementing the GF(2¹²⁸) multiplier, which is responsible for the authentication task in AES-GCM, to support high-speed applications. Additionally, an efficient AEGIS-128is also implemented using only five AES rounds. Our hardware implementations were evaluated using Virtex-5 and Virtex-4 FPGAs. The performance of the presented architectures (Thr./Slices) outperforms the previously reported ones.The second part of the thesis presents techniques for low cost solutions in order to secure the reconfiguration of FPGAs. We present different ranges of low cost implementations of AES-GCM, AES-CCM, and AEGIS-128, which are used in the static part of the FPGA in order to decrypt and authenticate the FPGA bitstream. Presented ASIC architectures were evaluated using 90 and 65 nm technologies and they present better performance compared to the previous work
Guyot, Dimitri. "Evaluation sur modèle de simulation thermique dynamique calibré des performances d’un contrôleur prédictif basé sur l’utilisation de réseaux de neurones". Thesis, Paris, HESAM, 2020. http://www.theses.fr/2020HESAC022.
Texto completo da fonteThe development of machine learning techniques, particularly neural networks, combined with the development of new information and communication technologies, is shaking up our societies through technological advances in a variety of sectors. The building sector is not spared, so these techniques may represent an interesting opportunity in a context where greenhouse gas emissions must be drastically reduced. The objective of this work is to assess the interest of these techniques in the field of building energy, with the aim of reducing energy consumption and improving thermal comfort. In addition, we ensure that this evaluation is carried out with a global vision, by placing the possible advantages in front of the different needs relating to the development of these technologies. This thesis work is organized in three parts preceded by a detailed introduction intended to give the reader an overview of the various contextual elements, thus allowing the thesis work to be placed in perspective. We then give in the first part the theoretical framework needed to understand the problems encountered during the elaboration and creation of neural networks for building energy applications. Then, a bibliographical study giving the reader a broad overview of the various applications of neural networks in the field of building energy is presented. The second part is devoted to the calibration of the building model that is then used to test and evaluate a predictive controller implementing neural networks. After an explanation of the method used and a detailed presentation of the model, a complete analysis of the calibration results is carried out. We conclude this part with observations and recommendations regarding the standard calibration guidelines recommended by three international organizations. Finally, a practical application using neural networks for the predictive control of indoor temperature is presented in the third part. After a theoretical introduction concerning predictive control, we detail the method employed to train the neural networks used. The results obtained in simulation with a predictive controller are then analyzed and compared with those obtained with two reference controllers for various simulation hypothesis. The predictive controller is thus tested in several scenarios, ranging from an ideal situation to more realistic operating conditions, including two different types of heat emitters, namely radiant ceilings and underfloor heating
Abdelmalek, Saif Eddine. "Algorithme de transfert intercellulaire vertical pour les réseaux sans fil hétérogènes basé sur le filtrage de Kalman". Mémoire, École de technologie supérieure, 2011. http://espace.etsmtl.ca/936/1/ABDELMALEK_Saif_Eddine.pdf.
Texto completo da fonteAbdelhamid, Zebdi. "DZ-MAODV : nouveau protocole de routage multicast pour les réseaux adhoc mobiles basé sur les zones denses". Thèse, Université du Québec à Trois-Rivières, 2006. http://depot-e.uqtr.ca/1323/1/000135082.pdf.
Texto completo da fonteBergeron, Cyril. "Optimisation conjointe source/canal d'une transmission vidéo H. 264/AVC sur lien sans fil". Paris, ENST, 2007. https://pastel.hal.science/pastel-00004234.
Texto completo da fonteMoussa, Ali Abdellatif Karim. "Chiffrement authentifié sur FPGAs de la partie reconfigurable à la partie static". Thesis, Paris 6, 2014. http://www.theses.fr/2014PA066660/document.
Texto completo da fonteCommunication systems need to access, store, manipulate, or communicate sensitive information. Therefore, cryptographic primitives such as hash functions and block ciphers are deployed to provide encryption and authentication. Recently, techniques have been invented to combine encryption and authentication into a single algorithm which is called Authenticated Encryption (AE). Combining these two security services in hardware produces better performance compared to two separated algorithms since authentication and encryption can share a part of the computation. Because of combining the programmability with the performance ofcustom hardware, FPGAs become more common as an implementation target for such algorithms. The first part of this thesis is devoted to efficient and high-speed FPGA-based architectures of AE algorithms, AES-GCM and AEGIS-128, in order to be used in the reconfigurable part of FPGAs to support security services of communication systems. Our focus on the state of the art leads to the introduction of high-speed architectures for slow changing keys applications like Virtual Private Networks (VPNs). Furthermore, we present an efficient method for implementing the GF($2^{128}$) multiplier, which is responsible for the authentication task in AES-GCM, to support high-speed applications. Additionally, an efficient AEGIS-128is also implemented using only five AES rounds. Our hardware implementations were evaluated using Virtex-5 and Virtex-4 FPGAs. The performance of the presented architectures (Thr./Slices) outperforms the previously reported ones.The second part of the thesis presents techniques for low cost solutions in order to secure the reconfiguration of FPGAs. We present different ranges of low cost implementations of AES-GCM, AES-CCM, and AEGIS-128, which are used in the static part of the FPGA in order to decrypt and authenticate the FPGA bitstream. Presented ASIC architectures were evaluated using 90 and 65 nm technologies and they present better performance compared to the previous work
Chevobbe, Stéphane. "Unité de commande pour systèmes parallèles : contrôleur basé sur la mise en oeuvre dynamique de réseaux de Pétri". Rennes 1, 2005. http://www.theses.fr/2005REN1S173.
Texto completo da fonteOkouyi, Antsina W'Ampoumou Rodrigue. "Faisabilité d'un système basé sur le DS-CDMA pour les futurs réseaux locaux sans fil à 60 GHz". Lille 1, 2006. http://www.theses.fr/2005LIL12024.
Texto completo da fonteRenault, Éric. "Étude de l'impact de la sécurité sur les performances dans les grappes de PC". Versailles-St Quentin en Yvelines, 2000. http://www.theses.fr/2000VERS0016.
Texto completo da fonteAït, Ali Ahmed. "Amélioration de la mesure de la bande passante dans un réseau basé sur IP". Thesis, Nancy 1, 2007. http://www.theses.fr/2007NAN10088/document.
Texto completo da fonteThis thesis work is focused on the end-to-end available bandwidth measurement that has attracted extensive attentions this last decade. This parameter is useful for several network applications, however, its measurement with good accuracy still stays a challenge to take up. To improve the performance of the available bandwidth measurement techniques, we developed a new deterministic model of packet pair delays that takes into account the probing packet size parameter; and implemented it in a new measurement tool called IGMPS. Through measurements on several network testbed configurations, we evaluated IGMPS and found that it provides available bandwidth measurements with high accuracy. Using sensitivity and uncertainty analysis to study the proposed model, we investigated the sources of observed errors on the measurement tools. We found that these errors are likely to be inherent in delay measurement. Indeed, the timestamping operations at the sender end the receiver are mainly at the origin of the inaccuracy of the estimates provided by the available bandwidth measurement tools
Rekik, Mouna. "Routage géographique multi-chemin basé sur l’intelligence d’essaim pour réseaux de capteurs et d’actionneurs sans fil : application aux Smart Grids". Thesis, Lille 1, 2016. http://www.theses.fr/2016LIL10059/document.
Texto completo da fonteThe Smart Grid (SG) enables an intelligent management of the electrical grid. The implementation of SGs is conditional to the implementation of a communication infrastructure to exchange data between the entities connected to the grid. This thesis is positioned in the context of wireless sensor networks (WSN) in SGs. Through this work, we have proposed a data routing protocol for the communication network at the distribution level. First, we proposed GRACO, a new geographical routing protocol based on swarm intelligence for WSNs. GRACO uses the geographic routing as a main data routing mechanism, and a recovery process based on ant colony optimization to bypass communication voids. The protocol performances were validated through simulations. By comparing the results to the state of the art, the proposed protocol improves the network performances in terms of data delivery rate, end-to-end delay and delivery cost. Second, we proposed GRACO as the routing protocol for wireless neighborhood area networks (NANs) in SG. GRACO ensures all communication schemes, especially Point-to-Point communication while providing scalability and self-healing capabilities. The feasibility of the protocol in NANs was confirmed through simulations using parameters defined by NIST.Finally, we focused on the qualities of service (QoS) required by NAN's applications. We have added a QoS model to the proposed routing protocol to take account of NAN's communication requirements. The performances of the new protocol were validated through simulations. The results showed that the protocol can satisfy the most severe requirements in terms of reliability and end-to-end delay
Pardo, Fabrice. "Étude et réalisation d'un dispositif bistable optique basé sur l'excitation d'un mode guidé couplé par réseau dans une couche mince de silicium sur saphir". Paris 11, 1986. http://www.theses.fr/1986PA112161.
Texto completo da fonteThis thesis presents a theoretical study and the realization of an original all optical device allowing ultrafast switching, taking advantage of the excitation of guided modes in a non-linear thin film, equivalent to a high finesse resonant system. In the theoretical study carried out to describe resonant optical bistable devices, all first order effects related ta refractive index local variations in the non-linear medium are taken into account, for a high finesse resonator. Characteristics of the device, as the threshold for bistability, can then be determined with a better precision than in the "mean field" method. The theory, developed for a planar system, is extended ta a grating coupled system. The realization of silicon on sapphire (SOS) non-linear wave-guide is described, especially the etching of a diffraction grating with a 0. 33 um groove-spacing by photolithography technics. Stationary waves appearing in the photoresist deposited on the silicon layer con lead ta large variations of exposure in the resist depth and then ta large fluctuations of the silicon grating modulation depth, obtained by ionic etching. A linear study of the device has been performed ta determine the guided TE and TM mode characteristics ta carry out the non-linear study, 20 ns duration light pulses have been used. Highly contrasted subnanosecond switching has been observed
Lai, Cristian. "Modèle d'indexation sémantique de ressources de mémoires personnelle et collective basé sur une approche pair à pair". Compiègne, 2011. http://www.theses.fr/2011COMP1953.
Texto completo da fonteThe present thesis explores the use of a semantic approach for indexing resources that are shared among a community of users who are scattered in a peer-to-peer network. The thesis contributes to the studies of Semantic Indexing approaches that can be used both with resources owned within personal memories, and with resources that are shared in a distributed network. Because the system is generic, the exact nature of the distributed community can be left undefined but our narrower focus is on applications in the e-learning domain. To address the problem that resources have different types, an indexing system is proposed that is based on the user point of view and is performed manually. Indeed, because indices refer to the subjective information that is not necessarily contained in the resources or that are hard to extract from documents that are not textual, the indexing of such type of resources can only be done in an interactive way. We show that a unique approach can be taken that allows one to store documents in personal or collective memories. The approach requires suitable browsing interfaces for accessing ontologies that satisfy and facilitate indexing. We therefore also define an Indexing Patterns system for managing ontologies that can be utilized for creating indices. The method is intended to facilitate the browsing of ontologies by showing only that part of the ontology that is useful for indexing and can be employed by users of various operating systems. A related problem that we address concerns the difference between the publication context and the retrieval context. The solution poroposed in this thesis foresees different retrieval situations and queries during the time a resource is published and builds the index based on those assumptions. The intended practical application encapsulates in a transparent manner the functionalities that the user requires for managing the resources. The development of a prototype is guided by Architectural and Implementation descriptions of the indexing system, both of which are described in the thesis. Although the solution we offer is generic and can be used by different user communities, the approach benefits Domain Specific Communities in particular, by assisting specilized loose communities that are structured as peer to peer networks and that allow publishing and searching of documents
Jiao, Yunlong. "Pronostic moléculaire basé sur l'ordre des gènes et découverte de biomarqueurs guidé par des réseaux pour le cancer du sein". Thesis, Paris Sciences et Lettres (ComUE), 2017. http://www.theses.fr/2017PSLEM027/document.
Texto completo da fonteBreast cancer is the second most common cancer worldwide and the leading cause of women's death from cancer. Improving cancer prognosis has been one of the problems of primary interest towards better clinical management and treatment decision making for cancer patients. With the rapid advancement of genomic profiling technologies in the past decades, easy availability of a substantial amount of genomic data for medical research has been motivating the currently popular trend of using computational tools, especially machine learning in the era of data science, to discover molecular biomarkers regarding prognosis improvement. This thesis is conceived following two lines of approaches intended to address two major challenges arising in genomic data analysis for breast cancer prognosis from a methodological standpoint of machine learning: rank-based approaches for improved molecular prognosis and network-guided approaches for enhanced biomarker discovery. Furthermore, the methodologies developed and investigated in this thesis, pertaining respectively to learning with rank data and learning on graphs, have a significant contribution to several branches of machine learning, concerning applications across but not limited to cancer biology and social choice theory
Tournoux, Pierre Ugo. "Un protocole de fiabilité basé sur un code à effacement "on-the-fly"". Phd thesis, Université Paul Sabatier - Toulouse III, 2010. http://tel.archives-ouvertes.fr/tel-00547003.
Texto completo da fonteGénevé, Lionel. "Système de déploiement d'un robot mobile autonome basé sur des balises". Thesis, Strasbourg, 2017. http://www.theses.fr/2017STRAD024/document.
Texto completo da fonteThis thesis is part of a project which aims at developing an autonomous mobile robot able to perform specific tasks in a preset area. To ease the setup of the system, radio-frequency beacons providing range measurements with respect to the robot are set up beforehand on the borders of the robot’s workspace. The system deployment consists in two steps, one for learning the environment, then a second, where the robot executes its tasks autonomously. These two steps require to solve the localization and simultaneous localization and mapping problems for which several solutions are proposed and tested in simulation and on real datasets. Moreover, to ease the setup and improve the system performances, a beacon placement algorithm is presented and tested in simulation in order to validate in particular the improvement of the localization performances
Mouelhi-Chibani, Wiem. "Apprentissage autonome de réseaux de neurones pour le pilotage en temps réel des systèmes de production basé sur l'optimisation via simulation". Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2009. http://tel.archives-ouvertes.fr/tel-00725259.
Texto completo da fonteRitty, Alexandre. "CONCEPTION, RÉALISATION ET CARACTÉRISATION D'UN HAUT-PARLEUR ULTRA-DIRECTIF BASÉ SUR L'AUTO-DÉMODULATION NON LINÉAIRE". Phd thesis, Université du Maine, 2007. http://tel.archives-ouvertes.fr/tel-00201456.
Texto completo da fonteCe travail de thèse vise à améliorer les systèmes existants. Pour ce faire, un outil de dimensionnement et un prototype de démonstration sont réalisés.
Dans un premier temps, les principes fondamentaux de l'acoustique non linéaire permettant de comprendre le phénomène d'auto-démodulation sont rappelés. Ceci permet de conclure sur l'influence du champ d'ondes primaires sur le champ d'ondes secondaires et de déterminer les propriétés nécessaires au champ d'ondes primaires pour une utilisation comme haut-parleur directif. Les distorsions induites par l'auto-démodulation sont également mises en évidence. Les prétraitements usuels de réduction des distorsions sont ensuite détaillés et évalués à l'aide d'un algorithme de simulation afin de conclure sur leurs avantages et leurs conditions d'utilisation.
Afin d'obtenir une directivité très étroite et un fort niveau aux fréquences ultrasonores, un réseau de transducteurs est utilisé. Nous avons choisi de travailler avec des transducteurs à base de film PVDF. Dans un second temps, une modélisation décrivant le comportement des transducteurs réalisés à l'aide de film PVDF couplé à une cavité est proposée. Celle-ci permet d'estimer la pression acoustique rayonnée par une cellule élmentaire en fonction de différents paramètres tels que les dimensions de la cavité et les propriétés du film. Enfin, l'utilisation du modèle de rayonnement d'un réseau de sources permet de définir un réseau de cellules répondant aux exigences de cette application.
Finalement, un prototype de haut-parleur directif est réalisé. Il est caractérisé expérimentalement en régime linéaire (sans auto-démodulation) ainsi que pour une utilisation comme haut-parleur directif afin de réaliser une validation des différentes parties de l'étude.
Fenet, Serge. "Vers un paradigme de programmation pour les applications distribuées basé sur le comportement des insectes sociaux : application à la sécurité des réseaux". Lyon 1, 2001. http://www.theses.fr/2001LYO10261.
Texto completo da fonteVoiry, Matthieu. "Étude et conception d'un système automatisé de contrôle d'aspect des pièces optiques basé sur des techniques connexionnistes". Thesis, Paris Est, 2008. http://www.theses.fr/2008PEST0077/document.
Texto completo da fonteIn various industrial fields, the problem of diagnosis is of great interest. For example, the check of surface imperfections on an optical device is necessary to guarantee its operational performances. The conventional control method, based on human expert visual inspection, suffers from limitations, which become critical for some high-performances components. In this context, this thesis deals with the design of an automatic system, able to carry out the diagnosis of appearance flaws. To fulfil the time constraints, the suggested solution uses two sensors working on different scales. We present one of them based on Normarski microscopy, and the image processing methods which allow, starting from issued data, to detect the defects and to determine roughness in a reliable way. The development of an operational prototype, able to check small optical components, validates the proposed techniques. The final diagnosis also requires a classification phase. Indeed, if the permanent defects are detected, many “false” defects (dust, cleaning marks. . . ) are emphasized as well. This complex problem is solved by a MLP Artificial Neural Network using an invariant description of the defects. This representation, resulting from the Fourier-Mellin transform, is a high dimensional vector, what implies some problems linked to the “curse of dimensionality”. In order to limit these harmful effects, various dimensionality reduction techniques (Self Organizing Map, Curvilinear Component Analysis and Curvilinear Distance Analysis) are investigated. On one hand we show that CCA and CDA are more powerful than SOM in terms of projection quality. On the other hand, these methods allow using more simple classifiers with equal performances. Finally, a modular neural network, which exploits local models, is developed. We proposed a new classification problems decomposition scheme, based on the intrinsic dimension concept. The obtained data clusters of homogeneous dimensionality have a physical meaning and permit to reduce significantly the training phase of the classifier, while improving its generalization performances
Négru, Daniel. "Un Eco-système de Médias Réseaux basé sur la Conscience du Contexte, du Réseau et du Contenu à destination de l'Internet Media du Futur". Habilitation à diriger des recherches, Université Sciences et Technologies - Bordeaux I, 2013. http://tel.archives-ouvertes.fr/tel-01012046.
Texto completo da fonteSahade, Mohamad. "Un démonstrateur automatique basé sur la méthode de tableaux pour les logiques modales : implémentation et études de stratégies". Toulouse 3, 2006. http://www.theses.fr/2006TOU30055.
Texto completo da fonteBelloum, Adam Scander. "Étude d'un système multiprocesseurs reconfigurable dédié aux traitements d'images basé sur les processeurs de signaux". Compiègne, 1996. http://www.theses.fr/1996COMPD877.
Texto completo da fonteHillali, Yassin El. "Etude et réalisation d'un système de communication et de localisation, basé sur les techniques d'étalement de spectre, dédié aux transports guidés". Valenciennes, 2005. http://ged.univ-valenciennes.fr/nuxeo/site/esupversions/bc65c6c9-a961-4f5e-88e5-cac7be0268f3.
Texto completo da fonteThe aim of this work is to design a localization and communication system dedicated to guided automatic trains in order to enhance their exploitation and to increase their reliability. The principal function of this radar is to reduce the lost exploitation time caused by a broken-down train to allow the following train to estimate in real time the distance between them. The sensor is a cooperative radar composed by two couples of interrogators– transponders which equip the front and the rear of each train following a complete loop. The choice of the sensor type is directed towards the correlation radar, because it maximizes the output signal to noise ratio. Some original multiplexing techniques based on spreading spectrum have been developed to combine the localization and the communication functions inside the same device. This system must be able to work on open area and also in tunnel. The choice of Hyperfrequency front-ends has been done following this important characteristic. The whole system (Transmitter/Receiver) have been simulated in real conditions in order to validate the selected technical choices. Finally, we present some solutions to implement the computing algorithms on a FPGA devices. A mock-up has been realized and the first tests have been carried out on open area. The obtained results show that a range of about 700m could be reached. The proposed multiplexing techniques allow the system to establish a communication with different data rates among (97kb/s, 1. 6Mb/S, 5. 4Mb/s and 11. 27Mb/s)