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In recent years, hemp or flax fibers have shown a reinforcement potential that is not fully exploited, because reinforcements often come in short fibers and agro-composites are very sensitive to the quality and type of reinforcements. Associated with a polymer matrix, these reinforcements make it possible to develop agro-composites with high mechanical, thermal, phonic performance, etc. as well as good fitness. In this context, we want to master the development and characterization of high-performance agro-composites based on natural fibers by different shaping techniques (compression, injection or 3D manufacturing)., Ces dernières années, les fibres de chanvre ou du lin affichent un potentiel de renforcement qui n’est pas entièrement exploité, car les renforts se présentent souvent en fibres courtes et les agro-composites sont très sensibles à la qualité et au type de renforts. Associé à une matrice polymère, ces renforts permettent d’élaborer des agro-composites avec de hautes performances mécaniques, thermiques, phonique etc. ainsi qu’une bonne aptitude à la mise en forme. Dans ce contexte nous souhaitons maitriser l’élaboration et la caractérisation des agro-composites hautes performances à base de fibres naturelles par différentes techniques de mise en forme (compression, injection ou fabrication 3D).

National audience; The recent multiplication of autonomous visiting devices in cities of art and history calls for a conceptual framework that makes it possible to reverse design these devices, to identify the visiting strategies to which they respond, to map the strategies that are widely instrumented and those that are more neglected, and thus to open up avenues for the design of complementary devices. Integrating the results of the literature on the diversity of visiting strategies, our conceptual framework is built around five functionalities that are combined to respond to these strategies: (1) discovering an item of interest, (2) accessing the related information, (3) receiving what is transmitted, (4) engaging, (5) reasoning. Each functionality is then broken down into “Form”, then “Conceptual approach” and finally “Implementation”. The use of this framework in reverse design and design is illustrated by the autonomous visit devices of the city of Troyes and its stained glass.; La multiplication récente des dispositifs de visite autonome dans les villes d'art et d'histoire nécessite un cadre conceptuel permettant de rétro-concevoir ces dispositifs, d'identifier à quelles stratégies de visite elles répondent, de cartographier les stratégies qui sont largement instrumentées et celles qui ont été plus délaissées, et ainsi d'ouvrir des pistes pour la conception de dispositifs complémentaires. Intégrant les résultats de la littérature sur la diversité des stratégies de visite, notre cadre conceptuel est construit autour de cinq fonctionnalités à combiner pour répondre à ces stratégies : (1) découvrir un élément d‘intérêt, (2) accéder à l’information associée, (3) accueillir ce qui est transmis, (4) s'engager, (5) raisonner. Chaque fonctionnalité se décline en « Forme », puis en « Approche conceptuelle », et enfin en « Implémentation ». L'usage de ce cadre en rétro-conception et en conception est illustré sur les dispositifs de visite autonome de la ville de Troyes et de ses vitraux.

International audience; Following the trend towards open data, various cultural organisations offer information about their collections. However, these knowledge bases are not used to accompany a visit to historical monuments. We think that a possible explanation for this observation lies in the distinction between availability and accessibility of the knowledge offered: although these knowledge bases make this knowledge available, it is difficult for non-experts to make use of it and make it their own. Rather than a semantic approach to visiting based on description, we advocate an active and semiotic approach based on comparison. We have identi- fied four challenges in applying this approach to church stained-glass windows. The first two challenges are to link the physical space of the building and the stained glass with the documentary space so that visitors can move between the two. Visitors also need to understand and use 'reading keys' to match a represen- tation with its subject. Visitors should afterward finally be able to use their knowledge and skills on other visits. Through interviews and observations, we have iteratively designed paper and digital prototypes to meet these challenges.

International audience; The progress of science and technology has considerably increased the quality of life - especially the material standard of living - (e.g. disappearance of famines, increase in life expectancy) On the other hand, climate change, reduction of biodiversity, decrease of natural resources, and increase of environmental risks are some of the consequences of this human activities. Addressing these new challenges will require holistic comprehension and actionable approaches. The mitigation of these consequences requires effective responses in terms of transition. In this context, engineering and design students need time but also adapted curricula focused on sustainability and eco design concepts to support evolution of their skills, their knowledge and their culture. This article discusses the integration of a strong sustainability knowledge within the ideation process through a pedagogical experience, in order to develop new knowledge-based approaches, methodologies and tools

International audience

International audience; The Reverse JPEG Compatibility Attack can be used for steganalysis of JPEG images compressed with Quality Factor 100 by detecting increased variance of decompression rounding errors. In this work, we point out the dangers associated with this attack by showing that in an uncontrolled environment, the variance can be elevated simply by using a different JPEG compressor. If not careful, the steganalyst can wrongly misclassify cover images. In order to deal with the diversity associated to the devices or softwares generating JPEGs, we propose in this paper to build a deep learning detector trained on a huge dataset of downloaded images. Experimental evaluation shows that such a detector can provide operational false alarms as small as 10^{−4} , while still correctly classifying 90% of stego images. Furthermore, it is shown that this performance is directly applicable to other image datasets. As a side product, we indicate that the attack is not applicable to images developed with a specific JPEG compressor based on the trunc quantization function.

International audience; In this paper we conduct a qualitative case study on how knowledge management occurs within a regulated safety context that seeks to make its knowledge sustainable. Thus, organizations, which operate in this context, try jointly, to create, share and, above all, sustain this knowledge for a long time. The most effective way to meet their objectives is to redesign their inter-organizational architecture into a non-competitive knowledge ecosystem. The back and forth between the research field and the theory, led us to ask the following research question: how a regulated safety context should evolve into a non-pre-competitive knowledge ecosystem? To answer this research question, we adopted an organizational perspective, integrating knowledge management and organizational innovation streams. Our results show the emergence of a non-pre-competitive knowledge ecosystems where actors’ interactions are strictly collaborative due to its main goal: sustainable and inter-organizational knowledge management. This emergence is enabled by internal and inter-organizational innovation, i.e., the development of a knowledge management process. Organizational innovation is articulated within the actors’ own (intra-organizational) knowledge systems, but also through the knowledge flow that is exchanged at the inter-organizational level. To achieve this, ecosystem governance is ensured by a focal actor (through regulatory legitimacy) who assumes the role of orchestrator, to sustain the knowledge flow through coordination and collaboration of ecosystem members.

Nickel titanium alloys are capable of inducing a large reversible deformation or recovery force due to martensitic transformation induced by thermomechanical loading. This research project aims to provide a tool to help design innovative medical applications to optimize material microstructure cell in relation to the desired functionality (recovery force, damping, energy absorption), to lighten the structure and to 3D additive manufacturing; Les alliages de nickel-titane sont capables d'induire une grande force de déformation ou de récupération réversible due à la transformation martensitique induite par le chargement thermomécanique. Ce projet de recherche vise à fournir un outil d'aide à la conception d'applications médicales innovantes permettant d'optimiser la microstructure cellulaire des matériaux par rapport à la fonctionnalité recherchée (force de rappel, amortissement, absorption d'énergie), d'alléger la structure et de faire de la fabrication additive 3D.

International audience

The objective of this research project is to develop a digital tool to assist in the design of innovative AMF applications integrating a material and geometric optimization approach with respect to an objective of maximizing a functionality/weight ratio ( actuation/weight, damping/weight, activation energy/weight, etc…)., L’objectif de ce projet de recherche consiste à développer un outil numérique d’aide à la conception d’applications innovantes en AMF intégrant une démarche d’optimisation matérielle et géométrique par rapport à un objectif de maximisation d’un ratio fonctionnalité/poids (actionnement/poids, amortissement/poids, énergie d’activation/poids, etc…).

PurposeMost of the existing studies on the evolution of emergency topics in social media focused on the emergency information demand of fixed user type in emergency while ignoring the changing roles of stakeholders during the emergency. Thus in this study, a three-dimensional dynamic topic evolution model is proposed, in which fine grained division of time, dynamic identification of stakeholders in the emergency, and emergency topic evolution based on both timeline and stakeholder's type are all considered.Design/methodology/approachParticularly the relevance between the tweets posted and the topic of emergency, the influence on the social network, and the attention of emergency topic are as well taken into account to quantitatively calculate the weight and ranking of stakeholders at different stages of the emergency. To verify the proposed model, an experimental demonstration was carried out under an emergency event posted on social media.FindingsThe results show that (1) based on the three-dimensional dynamic topic evolution model, the composition and ranking of stakeholders have obvious differences at different stages; (2) the emergency information needs and the sharing behavior of stakeholders on emergency information also indicate different preferences where the topic concerns of stakeholders at different stages have a strong relationship with their weight ranking; (3) the emergency topic evolution considering both the dynamics of emergency stakeholders and emergency information demand could more accurately reflect the changing regularity of social media users' attention to information in emergency events.Originality/valueThis study is one of first to investigate the emergency topic evaluation on social media by considering the dynamic changes of various stakeholders in emergency. It could not only theoretically provide more accurate method to understand how users share and search emergency information in social media, but also practically signify an information recommendation way in social media for emergency tracking.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/OIR-02-2021-0098.

International audience; The automated conveyor system, as the core component in the modern manufacturing world, has gained lots of attention from researchers. To optimize the operation of the conveyor system, range-inspection control (RIC) has been considered an efficient strategy to bring this conventional technology to an intelligent level. Various algorithms have been put into use to achieve optimal control. However, the current methodologies are only focusing on control optimization, not scaled into the smart manufacturing framework. The schema of alignment and corporation between the physical and virtual spaces for the system remains an important problem. Therefore, the work in this article aims for an effective framework of implementation between the physical and virtual stations in an automated conveyor system. Since increasingly more application scenarios rely on the digital twin (DT) technology to realize the integration of physical and virtual systems, we proposed the DT automated conveyor system (DT-ACS) that constructs the road map to implement the RIC-based conveyor system under the background of a smart factory. Besides, profit-sharing-based deep Q-networks (PDQNs) have been proposed to cope with the RIC optimization problem. The robustness and efficiency of the proposed PDQN were evaluated via sets of experiments. The discussion and conclusion are presented at last accordingly.

COVID’19 crisis management revealed several relationships problems due to missed collaboration between healthcare actors and socio-economic organizations. In fact, these actors didn’t work usually together indeed their interdependencies tasks. The government Healthcare authority asks to identify these types of problems. In this paper, first results of interviews with these actors are presented.This experience feedback formalization is focused on the influence of relationships between these actors and the consequences on the large sanitary crisis management as COVID’19 one.

International audience

International audience; We are interested in how issues relating to privacy and confidentiality are incorporated when using interactive services. Two smart home services based on the use of data from "smart" electricity meters have been evaluated to establish the guarantees and forms of interaction necessary for their appropriation. We show that, given the contextual, dynamic and social nature of privacy, normative responses such as those promoted by the regulator (predefinition of sensitive data, prior to use consent, privacy as the default setting) are insufficient. As mentioned in previous works, the design choices must promote as components of the systems the user control of data throughout the interaction, as well as transparency of the data, processing and actors. However, our results highlight an important dimension not previously addressed: the need to adopt a temporal and diachronic vision of privacy and to broaden the question of interaction beyond use by considering the life cycle of the service and of the relationship with its suppliers.; Nous nous intéressons à la façon dont les questions de vie privée et de sa préservation s'instancient dans l'utilisation de services interactifs. Deux services relatifs à l'habitat et basés sur l'exploitation de données issues de compteurs électriques « intelligents » ont été évalués pour établir les garanties et formes d'interactions nécessaires à leur appropriation. Nous montrons que, compte tenu de la nature contextuelle, dynamique et sociale de la privacy, les réponses normatives telles que celles promues par le législateur (prédéfinition des données sensibles, consentement a priori, privacy intégrée seulement au stade de la conception du système) sont insuffisantes. Comme cela a pu être évoqué dans des travaux antérieurs, les choix de conception doivent favoriser la maîtrise des données dans l'interaction en proposant des moyens d'actions et une transparence des données, traitements et acteurs, en tant que composantes des systèmes. Toutefois, nos résultats mettent en exergue une dimension importante non traitée jusqu'alors : la nécessité d'adopter une vision temporelle et diachronique de la privacy, pour élargir la question de l'interaction au-delà de l'utilisation en considérant la durée de vie du service et de la relation avec ses fournisseurs.

National audience

In this technical report , we aim to combine different protfolio allocation techniques with covariance matrix estimators to meet two types of clients' requirements: client A who wants to invest money wisely, not taking too much risk, and not willing to pay too much in rebalancing fees; and client B who wants to make money quickly, benefit from market's short-term volatility, and ready to pay rebalancing fees. Four portfolio techniques are considered (mean-variance, robust portfolio, minimum-variance, and equi-risk budgeting), and four covariance estimators are applied (sample covariance, ordinary least squares (OLS) covariance, cross-validated eigenvalue shrinkage covariance, and eigenvalue clipping). Some comparisons between the covariance estimators in terms of eigenvalue stability and four metrics (i.e. expected risk, gross leverage, Sharpe ratio and effective diversification) exhibit the superiority of the eigenvalue clipping covariance estimator. The experiments on the Russel1000 dataset show that the minimum-variance with eigenvalue clipping is the model suitable for client A, whereas robust portfolio with eigenvalue clipping is the one suitable for client B.

IHM'23 - 34e Conférence Internationale Francophone sur l'Interaction Humain-MachineAFIHM, Université de Technologie de Troyes; The attempt to link digital and ecological transitions is becoming increasingly present in scientific papers. Since the early 2000s, several new fields of research have developed, covering a very broad spectrum of domains, ranging from environmental computing to the sustainability of human-machine interactions. The diversity of research in these domains has allowed to explore different ways of understanding computing in relation to the ecological transition: at the technical level, at the interaction level, at the impact on social structures, and so on. This article aims at describing to what extent Sustainable HCI (SHCI) needs to deal with alignments between HCI and stakeholders’ values in the sustainable transition of socio-technical systems.; La tentative de lier les transitions numériques et écologiques est de plus en plus présente dans les articles scientifiques. Depuis le début des années 2000, plusieurs nouveaux champs de recherche se sont développés, couvrant un très large spectre de domaines, allant de l'informatique environnementale à la soutenabilité des interactions humain-machine. La diversité des recherches dans ces domaines a permis d'explorer différentes manières de comprendre l'informatique en relation avec la transition écologique : au niveau technique, au niveau des interactions, au niveau de l'impact sur les structures sociales, etc. Cet article vise à décrire dans quelle mesure l’interaction humain-machine soutenable (IHMS) doit traiter des alignements entre l'informatique et les valeurs des parties prenantes dans la transition soutenable des systèmes socio-techniques.

This study introduces new probabilistic constraints and objective functions to manage the uncertain nature of the renewable energy sources in single-item capacitated lot sizing problem for flow-shop configurations by integrating the capacity contract selection problem with multiple energy sources. The aim of the probabilistic models built by considering the different probabilistic constraints and objective functions is to provide a decision-making tool and to promote the use of renewable energy sources in manufacturing industry despite of their stochastic nature. Mixed Integer Non-Linear Programming models are proposed by integrating the uncertainty of the renewable energy sources based on different features. The developed models are tested on a small-size instance and the results of the models are compared in terms of economical, ecological and reliability aspects.

This article presents the GREENHOME environment, a toolkit providing several data analytical tools for metering household energy consumption and CO 2 footprint under different perspectives. GREENHOME enables a multi-perspective analysis of household energy consumption and CO 2 footprint using and combining several variables through various statistics and data mining algorithms. To test GREENHOME, the article reports on experiments conducted for modelling and forecasting energy consumption and CO 2 footprint in the context of the Triple-A European project.

International audience; The growing use of teleconsultation, especially since the start of the Covid-19 pandemic, changes physicians' work at the hospital. In this paper, we set out to study how physicians have integrated teleconsultation into their healthcare practices. Moreover, we are interested in how teleconsultation software contributes to developing new medical practices and how the design of teleconsultation software can better support them. Based on 16 months of fieldwork in a general hospital that offers two different teleconsultation software, we have investigated teleconsultation practices through interviews and observations involving ten physicians doing teleconsultation and a telemedicine secretary. Unlike the existing informal remote care by phone, we observe that teleconsultation supports new formal healthcare practices, particularly for patient care management and inter-organizational cooperation. While analyzing the integration of teleconsultation in physicians' practices, we highlight that both pieces of software do not support those practices on equal terms according to their design. We argue that teleconsultation software design can limit the spread of these new healthcare practices and that the artifact ecology of physicians should be considered during the design process.

The problem of determining economic production quantities and demands, with respect to prices for a hybrid manufacturing / remanufacturing system is addressed in this paper. Most of studies in the literature consider same market for new and remanufactured (as-good-as new assumption) and separate production line. We consider in this paper that products are processed on a common line and are sold in distinct market with price sensitive demands. The problem is modelled and solved with a non-linear model. A numerical analysis is developed to validate the model and analyze its feasibility and limits.

International audience; Objectives: Convolutional neural networks (CNNs) have established state-of-the-art performance in computer vision tasks such as object detection and segmentation. One of the major remaining challenges concerns their ability to capture consistent spatial and anatomically plausible attributes in medical image segmentation. To address this issue, many works advocate to integrate prior information at the level of the loss function. However, prior-based losses often suffer from local solutions and training instability. The CoordConv layers are extensions of convolutional neural network wherein convolution is conditioned on spatial coordinates. The objective of this paper is to investigate CoordConv as a proficient substitute to convolutional layers for medical image segmentation tasks when trained under prior-based losses.Methods: This work introduces CoordConv-Unet which is a novel structure that can be used to accommodate training under anatomical prior losses. The proposed architecture demonstrates a dual role relative to prior constrained CNN learning: it either demonstrates a regularizing role that stabilizes learning while maintaining system performance, or improves system performance by allowing the learning to be more stable and to evade local minima.Results: To validate the performance of the proposed model, experiments are conducted on two well-known public datasets from the Decathlon challenge: a mono-modal MRI dataset dedicated to segmentation of the left atrium, and a CT image dataset whose objective is to segment the spleen, an organ characterized with varying size and mild convexity issues.Conclusion: Results show that, despite the inadequacy of CoordConv when trained with the regular dice baseline loss, the proposed CoordConv-Unet structure can improve significantly model performance when trained under anatomically constrained prior losses.

International audience

International audience

Effective capture of polar volatile organic compounds under environmental conditions is a challenge owing to the adsorption competition between polar volatile organic compounds and water.

International audience; The growth of e-commerce, stimulated by wider access to Internet services for both customers and companies buying and selling products through this channel, has generated a huge potential for consolidation and coordination of flows through multi-level distribution systems. In addition, to address the particular challenges of the last mile, the transition from the use of internal combustion engine vehicles (ICEVs) to alternative fuel vehicles (AFVs), the implementation of access restrictions in densely populated areas, and the integration of Customer-to-Parcel (C2P) stations (e.g., lockers and pick-up points) have become frequently adopted measures. In contrast to the classical two-echelon vehicle tour problem (2E-VRP), in this study, customers can be served either at C2P stations or by home delivery within a specified time window. We consider the satellites of the second echelon as potential C2P stations, and the grey areas are the home delivery customers located at the borders of the urban centres.; La croissance du e-commerce, stimulée par un accès plus large aux services Internet, tant pour les clients que pour les entreprises qui achètent et vendent leurs produits par ce canal, a généré un énorme potentiel de consolidation et de coordination des flux à travers des systèmes de distribution multi-échelons. De plus, pour répondre aux défis particuliers du dernier kilomètre, la transition de l'utilisation de véhicules à moteur à combustion interne (ICEV) vers des véhicules à carburant alternatif (AFV), la mise en place de restrictions d'accès dans les zones densément peuplées et l'intégration de stations Customer-to-Parcel (C2P) (par exemple, des casiers et des points de retrait) sont devenues des mesures fréquemment adoptées. Contrairement au problème classique de tournées de véhicules à deux échelons (2E-VRP), dans cette étude, les clients peuvent être servis soit dans des stations C2P, soit par une livraison à domicile dans une fenêtre de temps spécifiée. Nous considérons les satellites du second échelon comme des potentielles stations C2P, et les zones grises sont constituées des clients en livraison à domicile situés aux frontières des centres urbains.

Arterial stiffness is a major condition related to many cardiovascular diseases. Traditional approaches in the assessment of arterial stiffness supported by machine learning techniques are limited to the pulse wave velocity (PWV) estimation based on pressure signals from the peripheral arteries. Nevertheless, arterial stiffness can be assessed based on the pressure–strain relationship by analyzing its hysteresis loop. In this work, the capacity of deep learning models based on generative adversarial networks (GANs) to transfer pressure signals from the peripheral arterial region to pressure and area signals located in the central arterial region is explored. The studied signals are from a public and validated virtual database. Compared to other works in which the assessment of arterial stiffness was performed via PWV, in the present work the pressure–strain hysteresis loop is reconstructed and evaluated in terms of classical machine learning metrics and clinical parameters. Least-square GAN (LSGAN) and Wasserstein GAN with gradient penalty (WGAN-GP) adversarial losses are compared, yielding better results with LSGAN. LSGAN mean ± standard deviation of error for pressure and area pulse waveforms are 0.8 ± 0.4 mmHg and 0.1 ± 0.1 cm2, respectively. Regarding the pressure–strain elastic modulus, it is achieved a mean absolute percentage error of 6.5 ± 5.1%. GAN-based deep learning models can recover the pressure–strain loop of central arteries while observing pressure signals from peripheral arteries.

International audience; A system subject to degradation is considered. The degradation is modelled by a gamma process. A condition-based maintenance policy with perfect corrective and an imperfect preventive actions is proposed. The maintenance cost is derived considering a Markov-renewal process. The statistical inference of the degradation and maintenance parameters by the maximum likelihood method is investigated. A sensibility analysis to different parameters is carried out and the perspectives are detailed.

National audience; Jusqu'à présent, la recherche sur la soutenabilité s’est centrée principalement au niveau macro sur les acteurs institutionnels et les efforts de changement systémique. Au niveau micro, les chercheurs ont étudié le choix des produits par les consommateurs et leur élimination après usage [1].Le projet D-TechnoSS, financé par l'Agence nationale de la recherche (ANR) (ANR-20-CE10-0006), vise à développer une meilleure compréhension des mécanismes de prise de conscience et de changements des comportements associés à l’adoption de démarches de conception participatives dans une posture de soutenabilité forte.Le projet D-TechnoSS vise à explorer la proposition d’une intégration forte entre société et système de production. Dans le cadre du projet, il sera question de favoriser la prise de conscience des défis sociétaux, de faciliter le changement de comportements peu soutenables et d’accompagner le système productif dans on retour au seuil des limites planétaires. La méthode de recherche est basée sur une approche expérimentale, pour proposer un modèle d’évaluation de la soutenabilité dans une posture de soutenabilité forte.Le projet D-TechnoSS a donc pour ambition de mieux comprendre et accompagner les transitions sociales ainsi que l’adaptation nécessaire du système de production et des méthodes de conception.

International audience; New services with low-latency (LL) requirements are one of the major challenges for the envisioned Internet. Many optimizations targeting the latency reduction have been proposed, and among them, jointly rearchitecting congestion control and active queue management (AQM) has been particularly considered. In this effort, the L4S (Low Latency, Low Loss and Scalable Throughput) proposal aims at allowing both Classic and LL traffic to cohabit within a single node architecture. Although this architecture sounds promising for latency improvement, it can be exploited by an attacker to perform malicious actions whose purposes are to defeat its LL feature and consequently make their supported applications unusable. In this paper, we exploit different vulnerabilities of L4S which are the root of possible attacks and we show that application-layer protocols such as QUIC can easily be hacked in order to exploit the over-sensitivity of those new services to network variations. By implementing such undesirable flows in a real testbed and characterizing how they impact the proper delivery of LL flows, we demonstrate their reality and give insights for research directions on their detection.; De nouveaux services avec des exigences de faible latence constituent un des défis majeurs de l'Internet envisagé pour le futur. Beaucoup d'optimisations ciblant la latence ont été proposés, et parmi elles, la ré-architecture conjointe du contrôle de congestion avec la gestion active des files d'attentes a été particulièrement considéré. Dans cette optique, la proposition L4S (Low Latency, Low Loss and Scalable Throughput) vise à permettre la coexistence entre du trafic classique et du trafic faible latence au sein du même noeud réseau. Bien que cette architecture semble prometteuse pour l'amélioration de la latence, elle peut être exploitée par un attaquant réalisant des actions malicieuses ayant pour but de déjouer la garantie de faible latence, rendant de fait les services associés instables.Dans cet article, nous exploitons différentes vulnérabilités de L4S qui sont au coeur des attaques possibles et nous montrons que des protocoles de niveau applicatif tel que QUIC peuvent être facilement détournés dans le but d'exploiter l'hypersensibilité de ces nouveaux services aux variations réseaux. En implémentant de tels flux indésirables dans un banc de tests réaliste, et en caractérisant de quelle manière ils impactent la cadence de livraison des paquets des flux faibles latence, nous démontrons leur réalité et donnons des pistes de recherche pour leur détection.

International audience

International audience; Nowadays, energy saving is one of the main concerns of companies. Therefore, different studies have developed and integrated methods to measure the energy consumption of machine tools. In this paper, an integrated economic production quantity (EPQ) model that considers energy consumption is analyzed. The concept of specific energy consumption (SEC) is used to evaluate the energy consumption during the production time of the machine.Three types of SEC, depending on the production rate, were considered. By minimizing the total cost, the status of the machine in the non-production phase, the optimal production rate, the optimal cycle time, and the influence of these different methods of measuring energy consumption are defined. The results of the study show that the difference in using the SEC -types model does not affect the state selection of the machine during the non-production phase but can change the optimal solutions of the overall system. From the manager's point of view, the choice of different models to represent the energy consumption of the machine leads to different optimal decisions. Numerical analysis are performed, and results are discussed.

International audience

International audience; In this paper, the maintenance optimization problem of multi-component system is considered. It is assumed that the exact cause of system failure might be masked. That is, the exact cause of failure is unknown, and we only know that it belongs to a set called mask set. Both opportunistic perfect preventive maintenance (OPPM) and perfect corrective maintenance are considered. Threshold of OPPM and inter-inspection interval are considered as decision parameters which are optimized using long-run cost rate criteria. The applicability of the proposed maintenance policy is investigated using an illustrative example.

Retailers with short lifetime products in stock always face a problem of whether new products should be ordered when on-hand products partially decay and how to deal with the old products if a new batch is ordered. In this article, we consider the sales of a perishable product with a fixed short lifetime in two shelves, where new items of the product in a regular shelf are sold in a preset normal price, and old items in a markdown (discount) shelf are sold in a discounted price. We study the problem of the joint ordering of new items and pricing of old items and propose a joint ordering and markdown policy when the demand of the product depends on its price, and freshness as well as unsatisfied demand is lost. First, we formulate a one-period model, in which the present shelf ages of items in the two shelves are considered and use the Karush–Kuhn–Tucker condition to analytically obtain the optimal solution of the joint ordering and markdown problem. Second, numerical experiments are conducted to evaluate the performance of the two-shelf policy when the optimal solution of the one-period model is applied to the multiperiod problem in the form of a myopic policy. The results show that the proposed two-shelf joint ordering and markdown policy for perishable products performs better than the traditional one-shelf policy. Note to Practitioners —In this article, we develop a joint ordering and markdown policy for perishable products deployed on two shelves: a regular shelf for fresh products and a markdown shelf for less fresh products. Although the closed-form policy is obtained for the one-period situation with deterministic demand, it is not difficult to extend it to the multiperiod case with random demand. This article not only reveals the underlying reason of employing both regular shelf and markdown shelf in the practice of retailing management for perishable products but also proposes an easy-to-implement ordering and markdown policy, which will bring higher profit than the traditional one-shelf policy and will improve the performance of managing a perishable products retailing system.

International audience

International audience; In this work, a multi-component series system is considered. The failure is not self-announced and the systemis periodically inspected. At inspection times, the failed components are repaired and the type of repairdepends on the failure time. The general maintenance actions are perfect corrective maintenance, imperfectcorrective maintenance and minimal corrective maintenance actions for the failed component, which can beconsidered as imperfect corrective maintenance for the whole system. The inspection interval is consideredas a decision parameter, and the maintenance policy is optimized using the long-run cost rate function basedon the renewal reward theorem.It is assumed that there is historical data storage for the system that includes information related to pastrepairs. It is considered that there is no information related to components’ lifetime distributions and theirparameters. The optimal decision parameter is derived considering historical data using density estimationand statistical learning algorithms like the random forest, KNN and Naïve Bayes. Eventually, the efficiencyof the proposed optimal decision parameter according to available data is compared to the one derived whereall information on the system is available.

International audience; When thousands of employees in a company meet a variety of resources and tools to build long term projects, the result is a knowledge explosion! the goal of companies since several years ago, is to build a successful strategy to manage knowledge. Traditional methods proved their limits in the era of data and connected devices, especially in enhancing links data among several services. In the current chapter we propose an approach based on profiling techniques as one support of knowledge sharing in large companies. Documents classification process allow us to link automatically profiles with documents that may potentially interest them. For this propose we present an algorithm of multi-labeled classification. On our behalf, building a list of profiles with indexed resources is not a finality, knowledge access and retrieval could be improved to more than 50% as our preliminary results proved, by exploring semantic links between profiles which are expressed deeply in documents.

International audience

This study reports research on Nickel etch mask used for deep plasma etching of silicon carbide (SiC) substrates, aiming to fabricate power integrated devices. Ni masks with significant thicknesses are requested when performing deep etches of SiC, which are less compatible with classic thin film physical vapor deposition (PVD) methods. Uniform and smooth plasma etched surfaces of SiC were obtained without micromasking phenomena upon using Ni masks deposed by electroplating. Detailed here is this Ni masks based technology we developed beyond its limitation, in order to obtain a high-etched thickness of silicon carbide substrates.

The objective of this paper is to discuss the problem of maintenance modelling and optimisation for a deteriorating Photo- voltaic panel system. In this paper, we model the dust accumulation process as PV panels’ as the main degradation cause considering the wind conditions as covariates. The dust accumulation process is mod- eled by a non-homogeneous compound Poisson process (NHCPP). The covariates process is assumed to be a time-homogenous Markov chain with finite state space. A model similar to the proportional hazards model is used to show the influence of covariates on the degradation process. In the framework of the system under consideration, an appropriate maintenance policy which minimises the long run average maintenance cost and maximises the long run average profits is derived. Numerical implementations are presented to illustrate the performance of the proposed model.

ERI Network & Telecom - EUt+ Workshop; New services are designed for the future of Internet, and some of them will require the network to provide low latency traffic. Many optimizations targeting latency reduction have been proposed. Among them, re-architecting congestion control and active queue management (AQM) has been particularly studied. L4S [1,2,3] (Low Latency, Low Loss and Scalable Throughput) is a new network architecture that aims at allowing coexistence between low latency traffic and classic traffic within a single node, involving a dual queue coupled AQM. Although this architecture sounds promising for latency improvement, an attacker can exploit some vulnerabilities to defeat its low-latency features and consequently make some services unusable. In addition, we prove that application-layer protocols such as QUIC can easily be hacked in order to exploit the over sensitivity of those new services to network variations. By implementing undesirable flows in a testbed and evaluating how they impact the delivery of low-latency flows, we demonstrate their reality and the need of research in the detection of this new kind of threats [4,5].; De nouveaux services sont conçus pour l'avenir de l'Internet, et certains d'entre eux exigeront que le réseau fournisse un trafic à faible latence. De nombreuses optimisations visant à réduire la latence ont été proposées. Parmi elles, la réarchitecture du contrôle de la congestion et de la gestion active des files d'attente (AQM) a été particulièrement étudiée. L4S [1,2,3] (Low Latency, Low Loss and Scalable Throughput) est une nouvelle architecture de réseau qui vise à permettre la coexistence du trafic à faible latence et du trafic classique au sein d'un même nœud, en faisant intervenir un AQM couplé à une double file d'attente. Bien que cette architecture semble prometteuse en termes d'amélioration de la latence, un attaquant peut exploiter certaines vulnérabilités pour contourner ses caractéristiques de faible latence et, par conséquent, rendre certains services inutilisables. En outre, nous prouvons que les protocoles de la couche application tels que QUIC peuvent facilement être piratés afin d'exploiter la sensibilité excessive de ces nouveaux services aux variations du réseau. En implémentant des flux indésirables dans un banc d'essai et en évaluant leur impact sur la livraison des flux à faible latence, nous démontrons leur réalité et le besoin de recherche dans la détection de ce nouveau type de menaces [4,5].