HAL Portal Univ-Côtedazur
Not a member yet
95391 research outputs found
Sort by
Unbalanced Triangle Detection and Enumeration Hardness for Unions of Conjunctive Queries
No full textInternational audienceWe study the enumeration of answers to Unions of Conjunctive Queries (UCQs) with optimal time guarantees. More precisely, we wish to identify the queries that can be solved with linear preprocessing time and constant delay. Despite the basic nature of this problem, it was shown only recently that UCQs can be solved within these time bounds if they admit free-connex union extensions, even if all individual CQs in the union are intractable with respect to the same complexity measure. Our goal is to understand whether there exist additional tractable UCQs, not covered by the currently known algorithms.As a first step, we show that some previously unclassified UCQs are hard using the classic 3SUM hypothesis, via a known reduction from 3SUM to triangle listing in graphs. As a second step, we identify a question about a variant of this graph task that is unavoidable if we want to classify all self-join-free UCQs: is it possible to decide the existence of a triangle in a vertex-unbalanced tripartite graph in linear time? We prove that this task is equivalent in hardness to some family of UCQs. Finally, we show a dichotomy for unions of two self-join-free CQs if we assume the answer to this question is negative.In conclusion, this paper pinpoints a computational barrier in the form of a single decision problem that is key to advancing our understanding of the enumeration complexity of many UCQs. Without a breakthrough for unbalanced triangle detection, we have no hope of finding an efficient algorithm for additional unions of two self-join-free CQs. On the other hand, a sufficiently efficient unbalanced triangle detection algorithm can be turned into an efficient algorithm for a family of UCQs currently not known to be tractable
Etude et amélioration de la localisation via RSSI BLE dans un contexte de sécurité d'accès
No full text
Model Agnostic Differentially Private Causal Inference
No full textEstimating causal effects from observational data is essential in fields such as medicine, economics and social sciences, where privacy concerns are paramount. We propose a general, model-agnostic framework for differentially private estimation of average treatment effects (ATE) that avoids strong structural assumptions on the data-generating process or the models used to estimate propensity scores and conditional outcomes. In contrast to prior work, which enforces differential privacy by directly privatizing these nuisance components and results in a privacy cost that scales with model complexity, our approach decouples nuisance estimation from privacy protection. This separation allows the use of flexible, state-of-the-art blackbox models, while differential privacy is achieved by perturbing only predictions and aggregation steps within a fold-splitting scheme with ensemble techniques. We instantiate the framework for three classical estimators-the G-formula, inverse propensity weighting (IPW), and augmented IPW (AIPW)-and provide formal utility and privacy guarantees. Empirical results show that our methods maintain competitive performance under realistic privacy budgets. We further extend our framework to support meta-analysis of multiple private ATE estimates. Our results bridge a critical gap between causal inference and privacy-preserving data analysis
Deconstructing the ADCs Paradigms
No full textBook of abstracts https://eventos.ull.es/file_manager/getFile/196877.htmlInternational audienceAndi-body conjugates (ADCs) are being touted as game-changing drugs in several cancers with once dismal prognoses, such as breast (HER2+, Her2 low, triple negative) or urothelial cancers. An elegant blend of biotechnology, chemistry and cytotoxicity, ADCs represent the state of the art in targeted therapies. ADCs are expected to embody the "magic bullet" first conceptualised by Paul Erlich in the early 20th century by delivering highly potent payloads to tumour cells in a targeted manner. The extent to which the concepts underlying the success of ADCs (such as targeting cancer antigens, specific distribution to tumours, extended therapeutic window, stable payload delivery) resist the facts is surprisingly not a question, as the scientific community has accepted these features as obvious. Here we list the main characteristics of ADCs and confront the claims with published data: are ADCs really the biological missiles they claim to be
Avoiding Pitfalls for Privacy Accounting of Subsampled Mechanisms Under Composition
No full textInternational audienceWe consider the problem of computing tight privacy guarantees for the composition of subsampled differentially private mechanisms. Recent algorithms can numerically compute the privacy parameters to arbitrary precision but must be carefully applied.Our main contribution is to address two common points of confusion. First, some privacy accountants assume that the privacy guarantees for the composition of a subsampled mechanism are determined by self-composing the worst-case datasets for the uncomposed mechanism. We show that this is not true in general. Second, Poisson subsampling is sometimes assumed to have similar privacy guarantees compared to sampling without replacement. We show that the privacy guarantees may in fact differ significantly between the two sampling schemes. In particular, we give an example of hyperparameters that result in ε ≈ 1 for Poisson subsampling and ε > 10 for sampling without replacement. This occurs for some parameters that could realistically be chosen for DP-SGD
Restricted Chase Termination: You Want More than Fairness
No full textInternational audienceThe chase is a fundamental algorithm with ubiquitous uses in database theory. Given a database and a set of existential rules (aka tuple-generating dependencies), it iteratively extends the database to ensure that the rules are satisfied in a most general way. This process may not terminate, and a major problem is to decide whether it does. This problem has been studied for a large number of chase variants, which differ by the conditions under which a rule is applied to extend the database. Surprisingly, the complexity of the universal termination of the restricted (aka standard) chase is not fully understood. We close this gap by placing universal restricted chase termination in the analytical hierarchy. This higher hardness is due to the fairness condition, and we propose an alternative condition to reduce the hardness of universal termination
Actes de la 12ème Conférence sur les Environnements Informatiques pour l'Apprentissage Humain
No full textInternational audienceLa conférence EIAH 2025 se développe, sous un prisme interdisciplinaire, autour des travaux sur les environnements informatiques pour l’apprentissage humain (EIAH) développés dans le cadre de différentes disciplines, parmi lesquelles la didactique, l’informatique, la psychologie, les sciences de l’éducation, les sciences du langage, les sciences de l’information et de la communication, la sociologie, etc.Le champ des EIAH couvre toutes les questions concernant la conception, la réalisation, la mise en œuvre, la validation, l'évaluation, la diffusion, l'usage et les effets des dispositifs informatiques destinés à faciliter les enseignements et les apprentissages, en contexte présentiel, à distance et/ou hybride, à destination des publics de l’enseignement primaire, secondaire, universitaire et/ou de la formation professionnelle
Le père et la mère des jeunes : référents de l’Aide Sociale à l’Enfance et intervenants associatifs comme associés-rivaux dans la prise en charge des MNA en région parisienne
No full textInternational audienc
Crise des savoirs scolaires et réponses aux défis globaux
No full textInternational audienceCet ouvrage examine en profondeur l’actuelle crise des savoirsscolaires à l’ère des défis globaux (environnement, sécurité,interculturalité, inégalités, énergies, laïcité, fake news, etc.). D’unepart, ces savoirs manquent de légitimité scientifique en l’absencede cursus universitaire capable de prendre en charge les enjeuxprécédents dans leur globalité et, d’autre part, ils apparaissent commetrop « empilés » face aux urgences politiques et sociétales, c’est-à-dire sans être appuyés sur une vraie réflexion épistémologique.Pour autant, l’institution scolaire continue d’évaluer, d’orienter et dedélivrer des diplômes dont la valeur s’érode peu à peu.Il y a donc urgence à repenser la pertinence des savoirs scolaires dansnos sociétés contemporaines afin de pouvoir aborder les problèmesdont on ne connaît pas encore les solutions. En explorant les enjeuxactuels de plusieurs « éducations à », les auteurs proposent despistes de réflexion et des réponses concrètes pour former les élèvesà une véritable pensée critique et créative. Ils donnent les clefs d’une« éducation au politique » susceptible de préparer les futurs citoyensaux défis auxquels ils auront à faire face, immanquablement.Un ouvrage essentiel pour tous ceux qui s’intéressent aux évolutionsde l’éducation et à la manière dont les savoirs peuvent répondre auxdéfis du XXIe siècle