Search

The magnetostatic vector fields in terms of harmonic scalar potentials scattered by near–surface air inclusion of arbitrary shape, embedded in a conductive ferromagnetic medium, are investigated. The hollow inclusion is illuminated by a current–carrying coil, which serves as the primary field. The do-main of interest is separated into homogeneous subdomains under the assumption of a suitable truncation of the region of magnetostatic activity at a long distance from the incident source. Therein, the field is considered negligible and consequently a perfect magnetic boundary condition is implied. On the other hand, the introduced methodology addresses the full coupling between the two interfaces, i.e. the plane that distinguishes the half–space ferromagnetic material from the open air and the arbitrary surface among the inclusion and the ferromagnetic region. To this end, continuity conditions are applied in a rigorous way, while the expected behavior of the fields, either as ascending or as descending are taken into account. The scattering problem is solved by means of a modal approach, where potentials associated with the half–space are expanded via cylindrical harmonic eigenfunctions, while those related with the inclusion’s arbitrary geometry admit a generalized–type formalism, being the key to our method. However, since the transmission conditions involve potentials with different eigenexpansions, we are obliged to rewrite cylindrical to generalized functions and vice versa, obtaining handy relationships in terms of easy–to–handle integrals, where orthogonality then would be feasible. Once done, the calculation of the exact solutions leads to infinite linear algebraic systems, whose solution is achieved trivially through standard cut–off techniques. Thus, we obtain the implicated fields in a general analytical and compact fashion, independent of the inclusion’s geometry. In order to demonstrate the efficiency of the analytical model approach, we assume the degenerate case of a spherical inclusion, whereas the air–cored coil simulation via a numerical procedure validates our generalized method. The calculation is very fast, rendering it suitable for use with parametric inversion algorithms.

International audience; A fast model for the eddy-current signal calculation of thin cracks at the vicinity of a conducting tube edge is presented. The model is based on the surface integral equation formalism using a dedicated Green's function. The approach followed for the construction of the Green's kernel and the primary field is the Truncated Region Eigenfunction Expansion (TREE) method.

International audience; Simulation of flaw detection by eddy-current testing requires the calculation of the eddy-current signal due to the presence of the flaw. In this paper, the surface integral method (SIM) is applied for the calculation of the crack signal in work-pieces composed of a conducting plate with a borehole. The adopted approach makes use of a Green’s operator that takes into account the effect of the borehole, thus the integral formalism is restricted to the crack surface only. The truncated region eigenfunction expansion (TREE) method is followed for the construction of the Green’s operator. Comparisons of the computed crack signal with numerical simulations carried out using a hybrid VIM-SIM approach and experimental results show excellent agreement.

International audience; The solution of the eigenvalue problem in bounded domains with planar and cylindrical stratification is a necessary preliminary task for the construction of modal solutions to canonical problems with discontinuities. The computation of the complex eigenvalue spectrum must be very accurate since losing or misplacing one of the thereto linked modes will have an important impact on the field solution. The approach followed in a number of previous works is to construct the corresponding transcendental equation and locate its roots in the complex plane using the Newton–Raphson method or Cauchy-integral-based techniques. Nevertheless, this approach is cumbersome, and its numerical stability decreases dramatically with the number of layers. An alternative, approach consists in the numerical evaluation of the matrix eigenvalues for the weak formulation for the respective 1D Sturm–Liouville problem using linear algebra tools. An arbitrary number of layers can thus be easily and robustly treated, with continuous material gradients being a limiting case. Although this approach is often used in high frequency studies involving wave propagation, this is the first time that has been used for the induction problem arising in an eddy current inspection situation. The developed method is implemented in Matlab and is used to deal with the following problems: magnetic material with a hole, a magnetic cylinder, and a magnetic ring. In all the conducted tests, the results are obtained in a very short time, without missing a single eigenvalue.

International audience; A fast model for the eddy-current signal calculation of thin cracks at the vicinity of a conducting tube edge is presented. The model is based on the surface integral equation formalism using a dedicated Green’s function. The approach followed for the construction of the Green’s kernel and the primary field is the Truncated Region Eigenfunction Expansion (TREE) method.

International audience; A semianalytical solution to the eddy-current induction problem in a conducting, nonmagnetic plate near a cylindrical through-holeis derived by means of the second-order vector potential and the domain truncation technique. The construction of a solution, which simultaneously satisfies the field continuity across the cylindrical surface of the hole and the planar interfaces of the plate, proves to be a very challenging problem, and thus, a special superposition of partial subsolutions is proposed. The presented solution is part of a more general development aiming at the calculation of the probe interaction with material flaws located in the vicinity of the hole by means of the integral equation formalism. These tasks will be the subject of a future paper. The comparison of the semianalytical results against both finite-element simulations as well as experimental data demonstrates excellent agreement.

The modern communications landscape requires reliable, high-speed, high- throughput and secure links and sessions between user equipment instances and the data network. The 5G core implements the newly defined 3GPP network ar- chitecture enabling faster connectivity, low latency, higher bit rates and network reliability. The full potential of this set of networks will support a set of critical Internet of Things (IoT) and industrial use cases. Nevertheless, several compo- nents and interfaces of the Next-Generation Radio Access Network (NG-RAN) have proven to be vulnerable to attacks that can potentially obstruct the net- work’s capability to provide reliable end-to-end communication services. Various inherent security flaws and protocol-specific weaknesses have also been identified within the 5G core itself. However, little to no research has gone into testing and exposing said core-related weaknesses, contrary to those concerning the NG-RAN. In this paper, we investigate, describe, develop, implement and finally test a set of attacks on the Packet Forwarding Control Protocol (PFCP) inside the 5G core. We find that, by transmitting unauthorised session control packets, we were able to disrupt established 5G tunnels without disrupting subscribers’ connectivity to the NG-RAN, thus hindering the detection of said attacks. We evaluate the identi- fied PFCP attacks in a drone-based scenario involving 5G tunnelling between two swarms.

International audience; A fast model for the eddy-current signal calculation of thin cracks emanating from a borehole in a conducting plate is presented. The model is based on the surface integral equation formalism using a dedicated Green’s function, which takes into account the effect of the borehole. The approach followed for the construction of the Green’s kernel and the primary field is the Truncated Region Eigenfunction Exapnsion (TREE) method

International audience; Rapid and accurate modeling of Eddy Current Testing (ECT) signal is required in many industrial areas. For example, crack detection via ECT is widely employed in aeronautics and aerospace industry to inspect riveted planar multilayered structures. In these structures, small narrow cracks (e.g. micro-cracks) may initiate at the edge of rivet holes (which can be considered as large volumetric flaws) and propagate through the PMS. This article proposes a new and efficient model, based on a coupled approach between Volume Integral Method (VIM) and Boundary Element Method (BEM), simulating ECT probe signals due to the presence of both narrow cracks located near volumetric flaws within a given PMS. Simulation results are compared with experimental and simulated signals obtained with a numerical code. The performance of the method, in terms of accuracy and computational time, is discussed and the perspectives opened are presented.

978-1-4613-8027-6; International audience; A fast integral equation model for the eddy-current signal calculation of thin cracks breaking the wall of a boreholein a conducting plate is presented. The model is based on the surface integral equation formalism using a dedicated Green’sfunction, which takes into account the effect of the borehole. The approach followed for the construction of the Green’s kerneland the primary field is the Truncated Region Eigenfunction Expansion (TREE) method.

International audience; A fast simulation tool of Eddy Current Testing (ECT) inspections, based on a Boundary Element Method (BEM), is proposed in this paper. Simulated signals consist in impedance variation of a coil due to multiple narrow cracks located in conductive planar multilayered structures (MLS). The cracks can have various shapes or orientations and can lie in any layers of the structure inspected. After a presentation of the method, validations results, consisting in comparison of simulated signals with experimental data and results obtained with finite element calculations, are presented. In all the problems tested, a very good accuracy and a very low computation time have been observed. Further perspective and conclusions of this work are detailed at the end of the paper.

International audience; Efficient modeling of Eddy Current Testing (ECT) signals is needed in many areas of industry. Probes design may be improved, and experimental signals interpretation may be better understood by using dedicated numerical simulation tools, provided that they are computationally effective and accurate, while remaining easy enough to be employed at end-user's level. A Boundary Element Method (BEM), dedicated to the numerical simulation of ECT signals due to complex narrow cracks affecting a Planar Multilayered Structure (PMS) and presenting arbitrary orientations is investigated herein. The theoretical formulation relies on the calculation of the dyadic Green operator, associated to the PMS, via appropriate vector wave functions expansions. Then, the use of the Discrete Complex Image Method followed by the application of the Generalized Pencil of Function (GPOF) method is proposed for the efficient computation of this operator. Validation results of the complete model, by comparison with experimental data in laboratory controlled condition and with data provided by a finite-element code, are presented and discussed.

International audience; Learning constraint networks is known to require a number of membership queries exponential in the number of variables. In this paper, we learn constraint networks by asking the user partial queries. That is, we ask the user to classify assignments to subsets of the variables as positive or negative. We provide an algorithm, called QuAcq2, that, given a negative example, elucidates a constraint of the target network in a number of queries logarithmic in the size of the example. The whole constraint network can then be learned with a polynomial number of partial queries. We give information theoretic lower bounds for learning some simple classes of constraint networks and show that our generic algorithm is optimal in some cases. We provide a version of QuAcq2 with a cutoff mechanism that controls the time to generate a query. Our experiments illustrate the good behavior of QuAcq2 in practice, especially in the case where QuAcq2 is executed to learn the missing constraints in a partially filled constraint model. Our experiments also show that QuAcq2 requires significantly fewer queries to learn a network than its predecessor QuAcq1.

ISBN-13: 978-0-7354-1129-6 ; ISSN: 0094-243X (print) - 1551-7616 (online); Simulation of Eddy Current Testing (ECT) signals due to real cracks constitutes a matter of interest in many industrial fields. Such complex flaws can be modeled as a succession of narrow crack with canonical shapes (i.e. slot, elliptical, semi-elliptical, etc.) having arbitrary positions and orientations. This paper present a semi-analytical model dedicated to the simulation of ECT inspections of stratified planar structures, affected by narrow crack. Validation of the developments, carried out with experimental data or by comparison with other numerical results, are then discussed.

Part 5: Autonomous Agents; International audience; Autonomous Vehicles (AVs) can potentially reduce the accident risk while a human is driving. They can also improve the public transportation by connecting city centers with main mass transit systems. The development of technologies that can provide a sense of security to the passenger when the driver is missing remains a challenging task. Moreover, such technologies are forced to adopt to the new reality formed by the COVID-19 pandemic, as it has created significant restrictions to passenger mobility through public transportation. In this work, an image-based approach, supported by novel AI algorithms, is proposed as a service to increase autonomy of non-fully autonomous people such as kids, grandparents and disabled people. The proposed real-time service, can identify family members via facial characteristics and efficiently ignore face masks, while providing notifications for their condition to their supervisor relatives. The envisioned AI-supported security framework, apart from enhancing the trust to autonomous mobility, could be advantageous in other applications also related to domestic security and defense.

Learning constraint networks is known to require a number of membership queries exponential in the number of variables. In this paper, we learn constraint networks by asking the user partial queries. That is, we ask the user to classify assignments to subsets of the variables as positive or negative. We provide an algorithm, called QUACQ, that, given a negative example, focuses onto a constraint of the target network in a number of queries logarithmic in the size of the example. The whole constraint network can then be learned with a polynomial number of partial queries. We give information theoretic lower bounds for learning some simple classes of constraint networks and show that our generic algorithm is optimal in some cases.

International audience; Interactive constraint acquisition is a special case of query-directed learning, also known as "exact" learning. It is used to assist non-expert users in modeling a constraint problem automatically by posting examples to the user that have to be classified as solutions or non-solutions. One significant issue that has not been addressed in the literature of constraint acquisition is the possible presence of uncertainty in the answers of the users. We address this by introducing Limited Membership Queries, where the user has the option of replying "I don't know", corresponding to "omissions" in exact learning. We present two algorithms for handling omissions. The first one deals with omissions that are independent events, while the second assumes that omissions are related to gaps in the user's knowledge. We present theoretical results about both methods and we evaluate them on benchmark problems. Importantly, our second algorithm can not only learn (a part of) the target network, but also the constraints that cause the user's uncertainty.

Neighbor discovery, one of the most fundamental bootstrapping networking primitives, is particularly challenging in decentralized wireless networks where devices have directional antennas. In this paper, we study the following fundamental problem, which we term oblivious neighbor discovery: How can neighbor nodes with heterogeneous antenna configurations discover each other within a bounded delay in a fully decentralised manner without any prior coordination or synchronisation? We establish a theoretical framework on the oblivious neighbor discovery and the performance bound of any neighbor discovery algorithm achieving oblivious discovery. Guided by the theoretical results, we then devise an oblivious neighbor discovery algorithm, which achieves guaranteed oblivious discovery with order-minimal worst case discovery delay in the asynchronous and heterogeneous environment. We further demonstrate how our algorithm can be configured to achieve a desired tradeoff between average and worst case performance.

© 2019 IEEE. We target the minimum cost design of a 5G network exploiting Small Cells (SCs) carried by Unmanned Aerial Vehicles (UAVs). In our architecture, UAV-SCs can be recharged by a set of ground sites, which provide energy capabilities thanks to the exploitation of micro-generation (i.e., locally produced energy) and batteries. In addition, the ground sites are connected by means of a set of optical fibers forming a tree-based topology. We then define an optimization problem to minimize the total installation costs of the ground sites, the optical network, the batteries, and the sources of micro-generation, while ensuring the coverage of the territory through the UAV-SCs. Results demonstrate that it is possible to notably reduce the total costs compared to a legacy solution, which assumes the installation of fixed Base Stations (BSs) to provide full territory coverage.

International audience; Providing adapted e-health services, applications, and platforms responds to a growing need for medical institutions like hospitals or even homes. Patients with long-term conditions, elderly, and dependent persons need to receive e-health services and assistance in a simple, continuous, and nonintrusive way. When the e-health ecosystem meets the needs of targeted people, and gains their acceptance, provided services help tackle the problems that face the world's population nowadays such as dependency, aging, and healthcare for all. According to the United Nations projections, in 2050, the old-age dependency ratio of the population aged over 65 years will be ~51.70%. This situation points to an issue of developing autonomic healthcare systems and platforms that help people manage their own health with new services and better adapt institutionally based services. Different standards can be used within the e-health ecosystem hence the network interoperability has to be considered carefully in the design of context-aware applications and services. Heterogeneity is present at different levels, and is still an open issue in e-health systems. In addition to the heterogeneity of patients' profiles and service characteristics, the health environment involves a wide range of required sensors and actuators (e.g., blood pressure and temperature, insulin delivery, appliance control, and presence sensors) that can be sometimes very close to the user like in Body Area Networks (BAN). Sensors usually use different wireless access methods that need to work together and communicate with the rest of the infrastructure (if it exists): gateways, servers, local smart objects, or with the intelligence existing in the medical institution, home, or in the cloud [4]. Due to the strong environmental heterogeneity where e-health services are provided, mechanisms of making autonomic decisions (e.g., diagnostics, continuous monitoring, alerts, and assistance) have to be identified and studied on different levels. For a given service or application, the automatic identification of required sensors and actuators should be ensured and tailored to the context of the person (e.g., health status, mobility, and dependency degree), and the characteristics/constraints of the communication technology and the platform being used. Other open issues concern the deployment and placement of sensors in the communication architecture. Service deployment should be optimized to guarantee the best network coverage, coordination between sensors and middleware or gateways, possible attachment to the network infrastructure, and delay tolerant networking aspects. Cohabitation of different access methods and communication technologies of sensors and other devices involves sensor/device discovery, network

International audience; In diesem Artikel werden die wesentlichen Ergebnisse einer Umfrage, die im Rahmen des NEARCH Projektes durchgeführt wurde, vorgestellt. Unsere Untersuchung betrifft drei Hauptpunkte, die von großer Bedeutung für die heutige Praxis der Archäologie sind. Erstens betrachten wir, wie sich die Öffentlichkeit die Archäologie vorstellt. Zweitens befassen wir uns mit den Werten, für welche die Archäologie in der öffentlichen Wahrnehmung steht. Und drittens untersuchen wir die sozialen Erwartungen, die in die Archäologie und den Archäologen gesetzt werden. Die NEARCH Umfrage zeigt deutlich, dass die Europäer viel von der Archäologie erwarten, und zwar in einem breiten Spektrum von Bereichen, und dass die Bodendenkmalpflege allgemein mit den verschiedenen archäologischen und kulturerblichen Gruppen konstruktiver zusammenarbeiten muss.; This article presents the key results of a major survey carried out by the NEARCH project on the public perception of archaeology and heritage across Europe. The analysis focuses on three main points of significance for contemporary archaeological practice. The first is the image of archaeology and its definition in the perception of the general public. The second concerns the values that archaeology represents for the public. The third focuses on the social expectations placed on archaeologists and archaeology. The NEARCH survey clearly indicates that there is a significant public expectation by Europeans that archaeology should work comprehensively across a broad range of areas, and that cultural heritage management in general needs to engage more with different archaeological and heritage groups.; Cet article présente les principaux résultats d'une grande enquête conduite dans le cadre du projet NEARCH sur la perception qu'a le public européen de l'archéologie et du patrimoine. L'analyse se concentre sur trois aspects d'importance pour la pratique contemporaine de l'archéologie. Le premier concerne l'image qu'a le grand public de l'archéologie et la définition qu'il en donne. Le second a trait aux valeurs que l'archéologie représente pour ce public. Le troisième porte sur les attentes de la société envers les archéologues et l'archéologie. L'enquête du projet NEARCH démontre clairement qu'il existe une forte demande du public européen pour la contribution de l'archéologie à de nombreux domaines, et pour une gestion du patrimoine culturel impliquant plus fortement les différents groupes intéressés par l'archéologie et le patrimoine.

International audience; Table constraints are important in constraint programming as they are present in many real problems from areas such as configuration and databases. As a result, numerous specialized algorithms that achieve generalized arc consistency (GAC) on table constraints have been proposed. Since these algorithms achieve GAC, they operate on one constraint at a time. In this paper we propose new filtering algo- rithms for positive table constraints that achieve stronger local consistency proper- ties than GAC by exploiting intersections between constraints. The first algorithm, called maxRPWC+, is a domain filtering algorithm that is based on the local con- sistency maxRPWC and extends the GAC algorithm of Lecoutre and Szymanek [23]. The second algorithm extends the state-of-the-art STR-based algorithms to stronger relation filtering consistencies, i.e., consistencies that can remove tu- ples from constraints’ relations. Experimental results from benchmark problems demonstrate that the proposed algorithms are quite competitive with standard GAC algorithms like STR2 in some classes of problems with intersecting table con- straints, being orders of magnitude faster in some cases.

International audience; CP solvers predominantly use arc consistency (AC) as the default propagation method. Many stronger consistencies, such as triangle consistencies (e.g. RPC and maxRPC) exist, but their use is limited despite results showing that they outperform AC on many problems. This is due to the intricacies involved in incorporating them into solvers. On the other hand, singleton consistencies such as SAC can be easily crafted into solvers but they are too expensive. We seek a balance between the efficiency of triangle consistencies and the ease of implementation of singleton ones. Using the recently proposed variant of SAC called Neighborhood SAC as basis, we propose a family of weaker singleton consistencies. We study them theoretically, comparing their pruning power to existing consistencies. We make a detailed experimental study using a very simple algorithm for their implementation. Results demonstrate that they outperform the existing propagation techniques, often by orders of magnitude, on a wide range of problems.

In manufacturing environments where the production horizon for a specific product can be limited to a few hours or shifts, statistical process monitoring based on control charts is strategic to cut scrap, rework costs, and meet due dates. In this article, a Markov chain model is proposed to design a fully adaptive Shewhart control chart in a process with finite production horizon. The proposed Markov chain model allows the exact computation of several statistical performance metrics, as well as the expected cost of the monitoring and operation process for any adaptive Shewhart control chart with an unknown but finite number of inspections. Illustrative examples show the implementation of the Vp chart in short runs producing a finite batch of products.

International audience; Mobile ad-hoc social networks (MASNs) are emerging as a self-configuring and self-organizing social networking paradigm, which enhance local interactions among mobile and handheld device users. However, the MASNs cannot be directly derived on demand for various Android systems from existing social networks (SNs) without having access to end-to-end IT network infrastructure. In this article, we propose a detailed solution called BASA which would help in rapidly building local mobile ad-hoc social networks on top of the current Android platform. BASA establishes a four-layer system architecture according to the underlying challenges and requirements in MASNs. BASA is implemented in an EU project named "SOCITIES". Our prototype shows that BASA is flexible to expedite various services

Recently, control charts plotting a statistic having a Student's t distribution have been proposed as an efficient solution to perform Statistical Process Control (SPC) in short production runs where the shift size of the in-control process mean from @m"0 to @m"1 is known a priori. The shift size is usually measured as a multiple @d of the in-control process standard deviation @s"0: but in practice, at the beginning of the production run, both the value of next shift @d and @s"0 are unknown. As a consequence, when the actual shift size differs from the value assumed at the chart design stage, the performance of the control chart can be seriously affected. To overcome this problem, this paper investigates the statistical performance of the Shewhart, EWMA and CUSUM t charts for short production runs when the shift size is unknown and modeled by means of a statistical distribution. An extensive numerical analysis allows the properties of the three charts to be compared and discussed when uniform and triangular distributions are used by quality practitioners to fit the unknown shift size. An illustrative example is utilized to demonstrate a practical implementation of the best performing among the three investigated charts.

Part 6: PLM Tools; International audience; When it comes to Engineering-To-Order (ETO) products, neither the exact number nor the form of the components in them can be predefined. Thus, existing assembly models and generative design techniques are not adequate to support development of design automation tools for ETO products. ETO companies usually use custom libraries with past case designs that are adjusted to a customer’s requirements. This method is not cost effective and it is prone to human errors. In this work, we present the Automatic Assembly Synthesis Model (AASM), connecting a Knowledge Based Engineering (KBE) system and a CAD system to automate routine design tasks for ETO mechanical products.

Conference of 42nd Annual Review of Progress in Quantitative Nondestructive Evaluation, QNDE 2015, Incorporating the 6th European-American Workshop on Reliability of NDE ; Conference Date: 26 July 2015 Through 31 July 2015; Conference Code:119404; International audience; In this paper, a numerical solution of WFNDEC 2015 eddy current benchmark is presented. In particular, the Surface Integral Equation (SIE) method has been employed for numerically solving the benchmark problem. The SIE method represent an effective and efficient alternative to standard numerical solver like Finite Element Method (FEM) when electromagnetic fields need to be calculated in problems involving homogeneous media. The formulation of SIE method allows to properly solve the electromagnetic problem by meshing the surface of the media instead to the complete media volume as done in FEM. The surface meshing enables to describe the problem with a smaller number of unknowns with respect to FEM. This property is directly translated in an obvious gain in terms of CPU time efficiency.

Part 1: Full Papers; International audience; Maintenance is one of the most effort consuming activities in the software development lifecycle. Efficient maintenance within short release cycles depends highly on the underlying source code structure, in the sense that complex modules are more difficult to maintain. In this paper we attempt to unveil and discuss relationships between maintenance productivity, the structural quality of the source code and process metrics like the type of a release and the number of downloads. To achieve this goal, we developed a Bayesian Belief Network (BBN) involving several maintainability predictors and three managerial indices for maintenance (i.e., duration, production, and productivity) on 20 open source software projects. The results suggest that maintenance duration depends on inheritance, coupling, and process metrics. On the other hand maintenance production and productivity depend mostly on code quality metrics.

Today, many companies use job production to produce small batches of work output according to customised specifications required by customers. With job production, the quantity of parts to be produced is finite and can be limited to a few thousands or hundreds (low-volume production). Usually, job production requires high-quality standards. When 100% sampling is not possible, online monitoring is a viable solution to immediately start process quality control. However, knowledge about the process distribution is frequently unavailable. Recently, it has been shown that the distribution-free Shewhart sign control chart is an efficient means to monitor processes performing high-volume production within a finite production horizon. In this paper, we reconsider the definition of the Shewhart sign chart statistic when the population size is small and we propose an approach that extends its implementation to finite batch sizes of work to be produced. Tables presenting the statistical properties of the Shewhart si...

International audience; A 2D numerical model for the solution of the eddy-current induction problem in non-linear hysteretic media is presented. The convergence of the iterative algorithm for the inversion of the non-linear operator is discussed. The numerical results are compared with simulations carried our using a commercial finite elements solver. Finally, an experimental procedure for obtaining the input material curves is presented.

International audience; In this paper, we study game dynamics and learning schemes for heterogeneous 4G networks. We introduce a novel learning scheme called cost-to-learn that incorporates the cost to switch, the switching delay, and the cost of changing to a new action and, captures the realistic behavior of the users that we have experimented on OPNET simulations. Considering a dynamic and uncertain environment where the users and operators have only a numerical value of their own payoffs as information, we construct various heterogeneous combined fully distributed payoff and strategy reinforcement learning (CODIPAS-RL): the users try to learn their own optimal payoff and their optimal strategy simultaneously. We establish the asymptotic pseudo-trajectories as solution of differential equations. Using evolutionary game dynamics, we prove the convergence and stability properties in specific classes of dynamic robust games. We provide various numerical examples and OPNET simulations in the context network selection in wireless local area networks (WLAN) and Long Term Evolution (LTE).

The recently proposed General Molecular Knotting algorithm and its associated package, MolKnot, introduce programming into certain sections of stereochemistry. This work reports the g-MolKnot procedure that was deployed over the Grid infrastructure; it applies a divide-and-conquer approach to the problem by splitting the initial search space into multiple independent processes and, combining the results at the end, yields significant improvements with regards to the overall efficiency. The algorithm successfully detected the smallest ever-reported alkane configured to an open-knotted shape with four crossings. fpsom@issel.ee.auth.gr (Psomopoulos, Fotis Evangelos) mitkas@eng.auth.gr (Mitkas, Pericles A) me00599@cc.uoi.gr (Krinas, Christos S) idimitr@uowm.gr (Demetropoulos, Ioannis Nikolaos) Aristotle University of Thessaloniki, Electrical and Computer Engineering - Thessaloniki - GREECE (Psomopoulos, Fotis Evangelos) Aristotle University of Thessaloniki, Electrical and Computer Engineering - Thessaloniki - GREECE (Mitkas, Pericles A) Democritus University of Thrace, Molecular Biology and Genetics - Alexandroupolis - GREECE (Krinas, Christos S) University of Western Macedonia, Department of Engineering Informatics and Telecommunications - K. Karamanli ang Lygeris--> - 50100 - Kozani - GREECE (Demetropoulos, Ioannis Nikolaos) GREECE

In many manufacturing environments, the production horizon of the same part code between two consecutive set-ups should be limited to a few hours or shifts. When 100 % sampling is not possible, on-line quality control on a quality characteristic should be immediately started by means of a control chart. In this paper, we investigate the statistical performance of a nonparametric (distribution-free) Shewhart Sign (SN) control chart for monitoring the location of a quality characteristic in a production process with a finite horizon and a small number of scheduled inspections. The observations taken from the process are assumed to be continuous random variables. By implementing a SN control chart, any model assumption about the distribution of observations is needless to guarantee a nominal in-control (IC) performance: after each process set-up, this overcomes the important problem of lack of information about the distribution of the observations collected for the quality characteristic to be monitored. An extensive simulation study is conducted to compare the statistical performance of the distribution-free Shewhart SN control chart to the normal theory-based Shewhart Student’s t control chart: several types of distributions of observations and different numbers of scheduled inspections are considered to show the advantages related to the implementation of the Shewhart SN control chart. An illustrative example presents the implementation of the Shewhart SN control chart on a real data set collected in a beverage company.

International audience; The poster reports on the design and the implementation of a pilot teaching intervention – part of my ongoing research – with two historical texts. The sample was a small group of Greek students of the 6th grade. On the poster I present the texts, the design, and photos of student’s activities.

We propose two local consistencies that extend bounds consistency (BC) by simultaneously considering combinations of constraints as opposed to single constraints. We prove that these two local consistencies are both stronger than BC, but are NP-hard to enforce even when constraints are linear. Hence, we propose two polynomial-time techniques to enforce approximations of these two consistencies on linear constraints. One is a reformulation of the constraints on which we enforce BC whereas the other is a polynomial time algorithm. Both achieve stronger pruning than BC. Our experiments show large differences in favor of our approaches.

International audience; Book Front Matter of LNCS 9248

Part 2: Open and Smart Government; International audience; A significant part of open data provided by governments and international organizations concerns statistics such as demographics and economic indicators. The real value, however, of open statistical data will unveil from performing analytics on top of combined datasets from disparate sources. Linked data provide the most promising technological paradigm to enable such analytics across the Web. Currently, however, relevant processes and tools do not fully exploit the distinctive characteristics of statistical data. The aim of this paper is to present a process that enables publishing statistical raw data as linked data, combining statistics from multiple sources, and exploiting them in data analytics and visualizations. Moreover, the capability of existing software tools to support the vision of linked statistical data analytics is evaluated. We anticipate that the proposed process will contribute to the development of a roadmap for future research and development in the area.

Molecular Communication (MC) is an emerging and promising communication paradigm for several multi-disciplinary domains like bio-medical, industry and military. Differently to the traditional communication paradigm, the information is encoded on the molecules, that are then used as carriers of information. Novel approaches related to this new communication paradigm have been proposed, mainly focusing on architectural aspects and categorization of potential applications. So far, security and privacy aspects related to the molecular communication systems have not been investigated at all and represent an open question that need to be addressed. The main motivation of this paper lies on providing some first insights about security and privacy aspects of MC systems, by highlighting the open issues and challenges and above all by outlining some specific directions of potential solutions. Existing cryptographicmethods and security approaches are not suitable for MC systems since do not consider the pecific issues and challenges, that need ad-hoc solutions.We will discuss directions in terms of potential solutions by trying to highlight the main advantages and potential drawbacks for each direction considered. We will try to answer to the main questions: 1) why this solution can be exploited in the MC field to safeguard the system and its reliability? 2) which are the main issues related to the specific approach?

International audience; The low-frequency electromagnetic scattering problem of a near-surface hollow spherical inclusion is solved by means of a modal approach. The primary field is excited using a current-carrying coil. The presented solution addresses the full coupling between the two interfaces of the geometry in a rigorous way. There is a direct physical interpretation of the different occurring terms in the formal solution, which provides a deeper understanding of the underlying phenomena. The calculation is very fast, which makes the proposed model suitable for use with parametric inversion algorithms.

41st Annual Review of Progress in Quantitative Nondestructive Evaluation (QNDE), Boise, ID, JUL 20-25, 2014; International audience; This work proposes a solution to the 2014 eddy current testing benchmark, published by the WFNDEC and proposed by the authors. The aim of this benchmark is to provide reference data for eddy current testing configurations involving magnetic sensors here Hall sensors as receivers, as they present some advantages in terms of resolution and sensitivity. After a presentation of the benchmark cases, the theoretical approach used to solve the equivalent electromagnetic problem is detailed and a alternative computation of eddy current signals is proposed. Then, simulations are quantitatively compared to experimental data in each case and the results are discussed.

The majority of work in cognitive radio networks have focused on single-hop networks with mainly challenges at the physical and MAC layers. Recently, multi-hop secondary networks have gained attention as a promising design to leverage the full potential of cognitive radio networks. One of the main features of routing protocols in multi-hop networks is the routing metric used to select the best route for forwarding packets. In this paper, we survey the state-of-the-art routing metrics for cognitive radio networks. We start by listing the challenges that have to be addressed in designing a good routing metric for cognitive radio networks. We then provide a taxonomy of the different metrics and a survey of the way they have been used in different routing protocols. Then we present a case study to compare different classes of metrics. After that, we discuss how to combine individual routing metrics to obtain a global one. We end the paper with a discussion of the open issues in the design of future metrics for cognitive radio networks.

International audience; Cloud computing is today’s most emphasized Information and Communications Technology (ICT) paradigm that is directly or indirectly used by almost every online user. However, such great significance comes with the support of a great infrastructure that includes large data centers comprising thousands of server units and other supporting equipment. Their share in power consumption generates between 1.1% and 1.5% of the total electricity use worldwide and is projected to rise even more. Such alarming numbers demand rethinking the energy efficiency of such infrastructures. However, before making any changes to infrastructure, an analysis of the current status is required. In this article, we perform a comprehensive analysis of an infrastructure supporting the cloud computing paradigm with regards to energy efficiency. First, we define a systematic approach for analyzing the energy efficiency of most important data center domains, including server and network equipment, as well as cloud management systems and appliances consisting of a software utilized by end users. Second, we utilize this approach for analyzing available scientific and industrial literature on state-of-the-art practices in data centers and their equipment. Finally, we extract existing challenges and highlight future research directions.

Conference of 40th Annual Review of Progress in Quantitative Nondestructive Evaluation, QNDE 2013, Incorporating the 10th International Conference on Barkhausen and Micro-Magnetics, ICBM 2013 ; Conference Date: 21 July 2013 Through 26 July 2013; Conference Code:105840; International audience; This work proposes a solution to the 2013 eddy current testing benchmark, published by the WFNDEC. The simulated results have been obtained by employing a newly developed semi-analytical approach, based on the coupled use of the classical Volume Integral Method (VIM) and the Boundary Element Method (BEM). An analytical overview on the coupled VIM-BEM approach is first given, in order to explain its theoretical background. Then, the results obtained are discussed from the points of view of accuracy and efficiency, respectively.

International audience; The solution to the eddy-current interaction problem between a probe coil and a cylindrical borehole in a planar conducting sheet is solved using the truncated region eigenfunction expansion (TREE) approach and decomposition into two subproblems of different parities: odd and even. The impedance variation of the probe is calculated and the theoretical results are compared with numerical ones obtained by the finite elements method as well as with measurements.

International audience; Book Front Matter of LNCS 8075

This article belongs to the Special Issue Vehicular Communications and Networking; International audience; Recent vehicular networking activities include novel automotive applications, such as public vehicle to vehicle/infrastructure (V2X), large scale deployments, machine-to-machine (M2M) integration scenarios, and more. The platform described in this paper focuses on the integration of eHealth in a V2I setting. This is to allow the use of Internet from a vehicular setting to disseminate health-related information. From an eHealth viewpoint, the use of remote healthcare solutions to record and transmit a patient’s vital signs is a special telemedicine application that helps hospital resident health professionals to optimally prepare the patient’s admittance. From the automotive perspective, this is a typical vehicle-to-infrastructure (V2I) communication scenario. This proposal provides an IPv6 vehicular platform, which integrates eHealth devices and allows sending captured health-related data to a personal health record (PHR) application server in the IPv6 Internet. The collected data is viewed remotely by a doctor and supports his diagnostic decision. In particular, our work introduces the integration of vehicular and eHealth testbeds, describes related work and presents a lightweight auto-configuration method based on a DHCPv6 extension to provide IPv6 connectivity with a few numbers of messages

Conference of 3rd International ICST Conference on Ambient Media and Systems, AMBI-SYS 2013 ; Conference Date: 14 March 2013 Through 15 March 2013; Conference Code:114922; International audience; Several convenience and efficiency applications have been proposed as part of recent vehicular networks (a.k.a. VANET) activities. Among these proposals, eHealth has often been studied as a time-critical application to emulate an ambulance. The Vehicle-To-Infrastructure (V2I) setting is the typical communication scenario to carry out the data in this case. From a user perspective, combining vehicular networking and eHealth to record and transmit a patient's vital signs is a special telemedicine application that helps hospital resident professionals to optimally prepare the patient's admittance. The current proposal pro-vides an IPv6 vehicular platform which integrates eHealth devices and allows sending captured user health-related data to a Personal Health Record (PHR) application server on the IPv6 Internet. The collected data are viewed remotely by a doctor and supports diagnostic decision. The resulting platform is then compared to the state-of-the-art related architectures. � Institute for Computer Sciences, Social Informatics and Telecommunications Engineering 2013.

One of the most widely studied classes of constraints in constraint programming (CP) is that of table constraints. Numerousspecialized filtering algorithms, enforcing the wellknown property called generalized arc consistency (GAC),have been developed for such constraints. Among the most successful GAC algorithms for table constraints, we find variants of simple tabular reduction (STR), like STR2. In this paper,we propose an extension of STR-based algorithms that achieves full pairwise consistency (FPWC), a consistency stronger than GAC and max restricted pairwise consistency (maxRPWC). Our approach involves counting the number of occurrences of specific combinations of values in constraint intersections. Importantly, the worst-case time complexity of one call to the basic filtering procedure at the heart of our new algorithm is quite close to that of STR algorithms. Experiments demonstrate that our method can outperform STR2 in many classes of problems, being significantly faster in some cases. Also, it is clearly superior to maxRPWC+, an algorithm that has been recently proposed.

International audience; Eddy current testing (ECT) of narrow cracks is an important issue in several industrial areas. Efficient modeling tools are required in order to better interpret measurements, to design adapted probes, and to assess the reliability of testing procedures. A dedicated boundary element model (BEM) suitable for eddy current inspection of several narrow cracks affecting a planar-stratified conductive medium is proposed. The cracks' openings can be arbitrarily small, and their respective orientations be along parallel or orthogonal directions. The approach alleviates most of the computational difficulties of classical methods in such peculiar cases. Comparisons of the results with experimental and simulated data taken from the literature, completed with in-house experiments, illustrate its good accuracy and low computational burden.