Academic literature on the topic 'Non convexes particules'
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Journal articles on the topic "Non convexes particules"
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Arnott, Richard. "Essai sur le risque moral." L'Actualité économique 63, no. 2-3 (2009): 74–97. http://dx.doi.org/10.7202/601411ar.
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Résumé Cet essai présente quelques-uns des résultats obtenus dans un projet de recherche à long terme sur le risque moral entrepris par l’auteur et Joseph Stiglitz. Le message central est que la présence du risque moral modifie radicalement les propriétés positives et normatives de l’équilibre concurrentiel. En particulier, le risque moral peut générer des courbes d’indifférence non convexes et un ensemble de possibilités non convexe. Principalement à cause de ces non-convexités, la définition de l’équilibre concurrentiel devient subtile. Selon la définition choisie, à un extrême, l’équilibre peut ne pas exister et, à l’autre extrême, il se peut qu’il y ait une infinité d’équilibres. De plus, l’équilibre concurrentiel peut être caractérisé par le rationnement des achats d’assurances, des profits positifs, de l’inactivité du marché même s’il y a des gains à l’échange, et/ou de l’assurance aléatoire. Finalement, sous le risque moral, ni le premier ni le second théorème de l’économie du bien-être ne sont valides et les prix du marché ne reflètent pas les coûts d’opportunité sociaux.
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Pronk, Matthijs, and Mark Veraar. "Forward integration, convergence and non-adapted pointwise multipliers." Infinite Dimensional Analysis, Quantum Probability and Related Topics 18, no. 01 (2015): 1550005. http://dx.doi.org/10.1142/s0219025715500058.
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In this paper we study the forward integral of operator-valued processes with respect to a cylindrical Brownian motion. In particular, we provide conditions under which the approximating sequence of processes of the forward integral, converges to the stochastic integral process with respect to Sobolev norms of smoothness α < 1/2. This result will be used to derive a new integration by parts formula for the forward integral.
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Pruschke, Thilo. "Notes on questions of W. Vogel concerning the converse to Bézout's theorem." Proceedings of the Edinburgh Mathematical Society 36, no. 3 (1993): 427–45. http://dx.doi.org/10.1017/s0013091500018526.
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Lazarsfeld proved a bound for the excess dimension of an intersection of irreducible and reduced schemes. Flenner and Vogel gave another approach for reduced, non-degenerate schemes which are connected in codimension one, using the intersection algorithm of Stückrad and Vogel and defining a new multiplicity k. Renschuch and Vogel considered a condition to ensure that there is no degeneration for more than two schemes. We define an integer which enables us to unify these methods. This allows us to generalize the result of Flenner and Vogel to non-reduced schemes by comparing the multiplicities j and k. Using this point of view we give applications to converses of Bézout's theorem; in particular we investigate the Cohen-Macaulay case.
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González-Cuerva, Rubén. "The Cloistered Ambassador: non-European Agents in the Convents of Madrid (1585-1701)." Culture & History Digital Journal 11, no. 1 (2022): e007. http://dx.doi.org/10.3989/chdj.2022.007.
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In line with its medieval predecessors, the Habsburg court had no particular problem in receiving representatives from outside the Christendom’s framework. Until 1580 these usually included Maghrebi envoys with an ambiguous status and without a notable diplomatic presence. Subsequently, the aggregation of the crown of Portugal to the Spanish Monarchy and the ceremonial standardization that gradually took place led, on the one hand, to the arrival of African and Asian agents of a different profile, with whom there was less familiarity, and on the other, to an attempt to assign them to the existing diplomatic categories. Among the numerous problems of Madrid as a reception centre for “exotic embassies,” we will look at the use of the city’s monasteries as accommodation for some of these agents and their entourage. Instead of being offered houses, these individuals were left in a provisional situation in accordance with their dubious diplomatic status, a policy that triggered problems of public order and decorum because of their difficult coexistence with the monastic communities. These and other monasteries played a further role as places of sociability and exchange for people who were not accustomed to such institutions. This will provide a glimpse into the complementarity between palaces and monasteries in a strongly confessionalised court and, paradoxically, into a kind of ceremonial flexibility that bordered on tolerance.
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Deugoué, Gabriel, та Mamadou Sango. "Strong solutions for the stochastic 3D LANS-α model driven by non-Gaussian Lévy noise". Stochastics and Dynamics 15, № 02 (2015): 1550011. http://dx.doi.org/10.1142/s0219493715500112.
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We establish the existence, uniqueness and approximation of the strong solutions for the stochastic 3D LANS-α model driven by a non-Gaussian Lévy noise. Moreover, we also study the stability of solutions. In particular, we prove that under some conditions on the forcing terms, the strong solution converges exponentially in the mean square and almost surely exponentially to the stationary solution.
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Feckan, Michal, and Kateryna Marynets. "Non-local fractional boundary value problems with applications to predator-prey models." Electronic Journal of Differential Equations 2023, no. 01-?? (2023): 58. http://dx.doi.org/10.58997/ejde.2023.58.
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We study a nonlinear fractional boundary value problem (BVP) subject to non-local multipoint boundary conditions. By introducing an appropriate parametrization technique we reduce the original problem to an equivalent one with already two-point restrictions. Using a notion of Chebyshev nodes and Lagrange polynomials we construct a successive iteration scheme, that converges to the exact solution of the non-local problem for particular values of the unknown parameters, which are calculated numerically.
 For mote information see https://ejde.math.txstate.edu/Volumes/2023/58/abstr.html
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BACCHELLI, BARBARA, MIRA BOZZINI, and MILVIA ROSSINI. "ON THE ERRORS OF MULTIDIMENSIONAL MRA BASED ON NON-SEPARABLE SCALING FUNCTIONS." International Journal of Wavelets, Multiresolution and Information Processing 04, no. 03 (2006): 475–88. http://dx.doi.org/10.1142/s0219691306001397.
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In this paper, we deal with two different problems. First, we provide the convergence rates of multiresolution approximations, with respect to the supremum norm, for the class of elliptic splines defined in Ref. 10, and in particular for polyharmonic splines. Secondly, we consider the problem of recovering a function from a sample of noisy data. To this end, we define a linear and smooth estimator obtained from a multiresolution process based on polyharmonic splines. We discuss its asymptotic properties and we prove that it converges to the unknown function almost surely.
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Thakur, Gauri, and J. K. Saini. "Comparative Study of Iterative Methods for Solving Non-Linear Equations." Journal of University of Shanghai for Science and Technology 23, no. 07 (2021): 858–66. http://dx.doi.org/10.51201/jusst/21/07229.
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In numerical analysis, methods for finding roots play a pivotal role in the field of many real and practical applications. The efficiency of numerical methods depends upon the convergence rate (how fast the particular method converges). The objective of this study is to compare the Bisection method, Newton-Raphson method, and False Position Method with their limitations and also analyze them to know which of them is more preferred. Limitations of these methods have allowed presenting the latest research in the area of iterative processes for solving non-linear equations. This paper analyzes the field of iterative methods which are developed in recent years with their future scope.
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Lederman, Jakob, Caroline Löfvenmark, Therese Djärv, Veronica Lindström, and Carina Elmqvist. "Assessing non-conveyed patients in the ambulance service: a phenomenological interview study with Swedish ambulance clinicians." BMJ Open 9, no. 9 (2019): e030203. http://dx.doi.org/10.1136/bmjopen-2019-030203.
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ObjectivesTo combat overcrowding in emergency departments, ambulance clinicians (ACs) are being encouraged to make on-site assessments regarding patients’ need for conveyance to hospital, and this is creating new and challenging demands for ACs. This study aimed to describe ACs’ experiences of assessing non-conveyed patients.DesignA phenomenological interview study based on a reflective lifeworld research approach.SettingThe target area for the study was Stockholm, Sweden, which has a population of approximately 2.3 million inhabitants. In this area, 73 ambulances perform approximately just over 200 000 ambulance assignments annually, and approximately 25 000 patients are non-conveyed each year.Informants11 ACs.MethodsIn-depth open-ended interviews.ResultsACs experience uncertainty regarding the accuracy of their assessments of non-conveyed patients. In particular, they fear conducting erroneous assessments that could harm patients. Avoiding hasty decisions is important for conducting safe patient assessments. Several challenging paradoxes were identified that complicate the non-conveyance situation, namely; responsibility, education and feedback paradoxes. The core of the responsibility paradox is that the increased responsibility associated with non-conveyance assessments is not accompanied with appropriate organisational support. Thus, frustration is experienced. The education paradox involves limited and inadequate non-conveyance education. This, in combination with limited support from non-conveyance guidelines, causes the clinical reality to be perceived as challenging and problematic. Finally, the feedback paradox relates to the obstruction of professional development as a result of an absence of learning possibilities after assessments. Additionally, ACs also described loneliness during non-conveyance situations.ConclusionsThis study suggests that, for ACs, performing non-conveyance assessments means experiencing a paradoxical professional existence. Despite these aggravating paradoxes, however, complex non-conveyance assessments continue to be performed and accompanied with limited organisational support. To create more favourable circumstances and, hopefully, safer assessments, further studies that focus on these paradoxes and non-conveyance are needed.
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Diu Tran, Thi Thanh. "Asymptotic behavior for quadratic variations of non-Gaussian multiparameter Hermite random fields." Probability and Mathematical Statistics 39, no. 2 (2019): 385–401. http://dx.doi.org/10.19195/0208-4147.39.2.8.
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Let Zt q,H t∈[0,1]d denote a d-parameter Hermite random field of order q ≥ 1 and self-similarity parameter H = H₁, . . . ,Hd ∈ ½, 1d. This process is H-self-similar, has stationary increments and exhibits long-range dependence. Particular examples include fractional Brownian motion q = 1, d = 1, fractional Brownian sheet q = 1, d ≥ 2, the Rosenblatt process q = 2, d = 1 as well as the Rosenblatt sheet q = 2, d ≥ 2. For any q ≥ 2, d ≥ 1 and H ∈ ½, 1d we show in this paper that a proper renormalization of the quadratic variation of Zq,H converges in L2Ω to a standard d-parameter Rosenblatt random variable with self-similarity index H' = 1 + 2H − 2/q.
Dissertations / Theses on the topic "Non convexes particules"
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Aponte, David. "Experimental and numerical investigation of geometric cohesion in granular systems composed ofhighly non-convex particles." Electronic Thesis or Diss., Université de Montpellier (2022-....), 2024. http://www.theses.fr/2024UMONS049.
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La résistance au cisaillement dans les matériaux granulaires s'explique souvent à l'aide du critère de rupture de Mohr-Coulomb. Ce critère repose sur deux paramètres clés : l'angle de frottement interne et la cohésion. L'angle de frottement interne est généralement lié à la rugosité et à la forme des particules, tandis que la cohésion est associée aux forces d'adhérence agissant entre les grains. Des recherches récentes ont introduit un nouveau domaine d'étude, mettant l'accent sur le potentiel des effets cohésifs dans les matériaux granulaires, sans nécessiter de forces d'adhérence. Ces études ont montré que dans les systèmes composés de particules de formes allongées (telles que les particules en forme de bâtonnet) ou de formes très non convexes (comme les particules en forme d'étoile), des effets cohésifs macroscopiques peuvent se développer en conséquence de la forme des particules et du frottement de contact. Cette thèse présente une étude sur ce phénomène, communément appelé ``cohésion géométrique''.Nous avons étudié la stabilité des systèmes colonnaires en utilisant à la fois des expériences et des simulations numériques. Notre objectif est d’explorer la relation entre la forme des particules et le développement de la cohésion géométrique au sein du système.Nos résultats réaffirment, dans la continuité des études précédentes, que la forme des particules est un facteur clé dans l’émergence de la cohésion géométrique et apportent un nouvel éclairage sur ce phénomène. En faisant varier systématiquement la forme des particules au sein d'une famille géométrique donnée, nous avons pu déterminer les formes optimales pour lesquelles les effets de cohésion sont maximisés. Nous avons également mis en évidence une relation claire entre le frottement de contact et la cohésion géométrique.Enfin, nous avons analysé la densité et la connectivité des systèmes bidimensionnels, en identifiant les caractéristiques microstructurales qui favorisent l’émergence d’un comportement de type solide dans ce type de systèmes granulaires<br>Shear strength in granular materials is often explained using the Mohr-Coulomb failure criterion.This criterion relies on two key parameters: internal friction angle and cohesion.The internal friction angle is typically linked to the roughness and shape of the particles, while cohesion is related to the adhesive forces acting between the grains.Recent research has introduced a new area of study, emphasizing the potential for cohesive effects in granular materials without the need for adhesive forces.These studies have shown that in systems composed of particles with elongated shapes (such as rod-shaped particles) or highly non-convex shapes (like star-shaped particles), macroscopic cohesive effects can develop as a consequence of particle shape and contact friction.This thesis presents an investigation on this phenomenon, commonly termed ``geometric cohesion''.We investigated the stability of columnar systems using both experiments and numerical simulations.Our objective was to investigate the relationship between particle shape and the development of geometric cohesion within the system.Our results reaffirm, in line with previous studies, that the shape of the particles is a key factor in the emergence of geometric cohesion, shedding new light on this phenomenon.By systematically varying the shape of the particles within a given geometric family, we were able to determine the optimal shapes for which the cohesive effects are maximized.We also found a clear relationship between contact friction and geometric cohesion.Finally, we analyzed the density and connectivity of two-dimensional systems, identifying the microstructural features that enable the emergence of solid-like behavior in this type of granular systems
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Saint-Cyr, Baptiste. "Modélisation des matériaux granulaires cohésifs à particules non convexes : Application à la compaction des poudres d'UO2." Phd thesis, Université Montpellier II - Sciences et Techniques du Languedoc, 2011. http://tel.archives-ouvertes.fr/tel-00660146.
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On s'intéresse à la modélisation des matériaux granulaires composé d'agrégats non convexes et cohésifs en vue d'application à la rhéologie des poudres d'UO2 . L'influence du degré de non-convexité des particules est analysé en termes de grandeurs macroscopiques (frottement interne et cohésion de Coulomb) et de paramètres micro-mécaniques tels que l'anisotropie de la texture et la transmission des efforts. Il apparaît en particulier que la compacité évolue d'une manière complexe avec la non-convexité et que la résistance au cisaillement augmente mais sature sous l'effet d'imbrication entre agrégats. Des modèles simples sont introduits pour décrire ces comportements en termes de paramètres micro-mécaniques. De même, des études systématiques par cisaillement, compaction uniaxiale et compression simple montrent que la cohésion interne augmente avec la non-convexité mais est fortement contrôlée par les conditions aux limites et l'apparition de bandes de cisaillement ou de concentrations de contraintes.
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Olmedilla, González de Mendoza Antonio. "Grain motion and packing : application to metallic alloy solidification." Thesis, Université de Lorraine, 2017. http://www.theses.fr/2017LORR0265/document.
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La modélisation multi-échelle multi-physique de la solidification d'alliages métalliques demande de combiner des phénomènes à l'échelle macroscopique du produit et microscopiques à l'échelle des structures de solidification. Dans cette thèse, l'empilement aléatoire des grains équiaxes avec des morphologies typiques de solidification est étudié. Nous mettons tout d'abord en évidence les paramètres hydrodynamiques adimensionnels qui régissent l'empilement de grains équiaxes : le nombre de Stokes, St, le nombre d'Archimède, Ar, et le rapport entre le temps caractéristique de la croissance et le temps caractéristique du mouvement, Γ. Un dispositif expérimental a été conçu par similitude hydrodynamique avec le phénomène réel de l'empilement de la solidification afin d'étudier l'influence de la géométrie des grains équiaxes et l'influence des conditions hydrodynamiques sur la fraction d'empilement. En outre, un outil numérique basé sur le méthode des éléments discrets a été développé pour compléter le travail expérimental de détermination de : la fraction d'empilement locale, le nombre de particules voisines en contact et l'orientation des particules. Des fractions d'empilement entre environ 0,53 et 0,67 ont été mesurées et calculées pour les grains sphériques non-cohésifs, alors que des valeurs allant jusqu'à environ 0,30 sont trouvées pour les grains dendritiques non-cohésifs. Enfin, nous étudions la dynamique de l'empilement, qui est la transition d'un régime de sédimentation à l'équilibre mécanique. L'évolution des variables comme la fraction locale de solide, le nombre de particules voisines en contact et l'orientation du grain en fonction du temps est présentée<br>Solidification multiphase multiscale modeling of metal alloys is based on the combination of the phenomena at the macroscopic scale of the product and at the microscopic scale of the solidification structures. In this thesis, the random packing of the typical equiaxed grain morphologies in metal alloy solidification is investigated. Firstly, we highlight the hydrodynamic dimensionless parameters governing the grain packing in the melt: the Stokes number, St, the Archimedes number, Ar, and the growth-to-motion ratio, Γ. Subsequently, an experimental setup is designed by hydrodynamic similarity with the actual solidification packing phenomenon in order to investigate the influence of the equiaxed grain geometry and the hydrodynamic conditions on the average solid packing fraction. Additionally, a numerical Discrete Element Method tool is developed to complement the experimental work by accessing to those granular variables which result difficult to be experimentally obtained such as the local packing fraction, the contacting neighbors and the particle orientation. Packing fractions between approximately 0.53 and 0.67 are measured and computed for the spherical noncohesive grains, for different hydrodynamic, frictional and polydispersity conditions, whereas values down to approximately 0.30 are found for noncohesive dendrite envelopes. Finally, we investigate the packing dynamics, which is the transition from a sedimentation regime to the mechanical equilibrium (packing). The evolution of the local solid fraction, contacting neighbors, mechanical contacts and grain orientation are given
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Rakotonirina, Andriarimina. "Fluid-solid interaction in a non-convex granular media : application to rotating drums and packed bed reactors." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEN047/document.
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Cette thèse porte sur l'étude numérique des écoulements fluide-particules rencontrés dans l'industrie. Ces travaux se situent dans le cadre de la compréhension des phénomènes qui se déroulent dans des tambours tournants et réacteurs à lit fixe en présence de particules de forme non convexe. En effet, la forme des particules influence de manière importante la dynamique de ces milieux. A cet effet, nous nous sommes servis de la plateforme numérique parallèle Grans3D pour la dynamique des milieux granulaires et PeliGRIFF pour les écoulements multiphasiques. Dans la première partie de cette thèse, nous avons développé une nouvelle stratégie numérique qui permet de prendre en compte des particules de forme arbitrairement non convexe dans le solveur Grains3D. Elle consiste à décomposer une forme non convexe en plusieurs formes convexes quelconques. Nous avons nommé cette méthode « glued-convex ». Le modèle a été validé avec succès sur des résultats théoriques et expérimentaux de tambours tournants en présence de particules en forme de croix. Nous avons aussi utilisé le modèle pour simuler le chargement de réacteurs à lits fixes puis des lois de corrélation sur les taux de vide ont été déduites de nos résultats numériques. Dans ces travaux, nous avons aussi testé les performances parallèles de nos outils sur des simulations numériques à grande échelle de divers systèmes de particules convexes. La deuxième partie de cette thèse a été consacrée à l'extension du solveur PeliGRIFF à pouvoir prendre en compte la présence de particules multilobées (non convexes) dans des écoulements monophasiques. Une approche du type Simulation Numérique Directe, basée sur les Multiplicateurs de Lagrange Distribués / Domaine Fictif (DLM/FD), a alors été adoptée pour résoudre l'écoulement autour des particules. Une série d'études de convergence spatiale a été faite basée sur diverses configurations et divers régimes. Enfin, ces outils ont été utilisés pour simuler des écoulements au travers de lits fixes de particules de forme multi-lobée dans le but d'étudier l'influence de la forme des particules sur l'hydrodynamique dans ces lits. Les résultats ont montré une consistance avec les résultats expérimentaux disponibles dans la littérature<br>Non convex granular media are involved in many industrial processes as, e.g., particle calcination/drying in rotating drums or solid catalyst particles in chemical reactors. In the case of optimizing the shape of catalysts, the experimental discrimination of new shapes based on packing density and pressure drop proved to be difficult due to the limited control of size distribution and loading procedure. There is therefore a strong interest in developing numerical tools to predict the dynamics of granular media made of particles of arbitrary shape and to simulate the flow of a fluid (either liquid or gas) around these particles. Non-convex particles are even more challenging than convex particles due to the potential multiplicity of contact points between two solid bodies. In this work, we implement new numerical strategies in our home made high-fidelity parallel numerical tools: Grains3D for granular dynamics of solid particles and PeliGRIFF for reactive fluid/solid flows. The first part of this work consists in extending the modelling capabilities of Grains3D from convex to non-convex particles based on the decomposition of a non-convex shape into a set of convex particles. We validate our numerical model with existing analytical solutions and experimental data on a rotating drum filled with 2D cross particle shapes. We also use Grains3D to study the loading of semi-periodic small size reactors with trilobic and quadralobic particles. The second part of this work consists in extending the modelling capabilities of PeliGRIFF to handle poly-lobed (and hence non-convex) particles. Our Particle Resolved Simulation (PRS) method is based on a Distributed Lagrange Multiplier / Fictitious Domain (DLM/FD) formulation combined with a Finite Volume / Staggered Grid (FV/SG) discretization scheme. Due to the lack of analytical solutions and experimental data, we assess the accuracy of our PRS method by examining the space convergence of the computed solution in assorted flow configurations such as the flow through a periodic array of poly-lobed particles and the flow in a small size packed bed reactor. Our simulation results are overall consistent with previous experimental work
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Liu, Yating. "Optimal Quantization : Limit Theorem, Clustering and Simulation of the McKean-Vlasov Equation." Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS215.
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Cette thèse contient deux parties. Dans la première partie, on démontre deux théorèmes limites de la quantification optimale. Le premier théorème limite est la caractérisation de la convergence sous la distance de Wasserstein d’une suite de mesures de probabilité par la convergence simple des fonctions d’erreur de la quantification. Ces résultats sont établis en Rd et également dans un espace de Hilbert séparable. Le second théorème limite montre la vitesse de convergence des grilles optimales et la performance de quantification pour une suite de mesures de probabilité qui convergent sous la distance de Wasserstein, notamment la mesure empirique. La deuxième partie de cette thèse se concentre sur l’approximation et la simulation de l’équation de McKean-Vlasov. On commence cette partie par prouver, par la méthode de Feyel (voir Bouleau (1988)[Section 7]), l’existence et l’unicité d’une solution forte de l’équation de McKean-Vlasov dXt = b(t, Xt, μt)dt + σ(t, Xt, μt)dBt sous la condition que les fonctions de coefficient b et σ sont lipschitziennes. Ensuite, on établit la vitesse de convergence du schéma d’Euler théorique de l’équation de McKean-Vlasov et également les résultats de l’ordre convexe fonctionnel pour les équations de McKean-Vlasov avec b(t,x,μ) = αx+β, α,β ∈ R. Dans le dernier chapitre, on analyse l’erreur de la méthode de particule, de plusieurs schémas basés sur la quantification et d’un schéma hybride particule- quantification. À la fin, on illustre deux exemples de simulations: l’équation de Burgers (Bossy and Talay (1997)) en dimension 1 et le réseau de neurones de FitzHugh-Nagumo (Baladron et al. (2012)) en dimension 3<br>This thesis contains two parts. The first part addresses two limit theorems related to optimal quantization. The first limit theorem is the characterization of the convergence in the Wasserstein distance of probability measures by the pointwise convergence of Lp-quantization error functions on Rd and on a separable Hilbert space. The second limit theorem is the convergence rate of the optimal quantizer and the clustering performance for a probability measure sequence (μn)n∈N∗ on Rd converging in the Wasserstein distance, especially when (μn)n∈N∗ are the empirical measures with finite second moment but possibly unbounded support. The second part of this manuscript is devoted to the approximation and the simulation of the McKean-Vlasov equation, including several quantization based schemes and a hybrid particle-quantization scheme. We first give a proof of the existence and uniqueness of a strong solution of the McKean- Vlasov equation dXt = b(t, Xt, μt)dt + σ(t, Xt, μt)dBt under the Lipschitz coefficient condition by using Feyel’s method (see Bouleau (1988)[Section 7]). Then, we establish the convergence rate of the “theoretical” Euler scheme and as an application, we establish functional convex order results for scaled McKean-Vlasov equations with an affine drift. In the last chapter, we prove the convergence rate of the particle method, several quantization based schemes and the hybrid scheme. Finally, we simulate two examples: the Burger’s equation (Bossy and Talay (1997)) in one dimensional setting and the Network of FitzHugh-Nagumo neurons (Baladron et al. (2012)) in dimension 3
Books on the topic "Non convexes particules"
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Epstein, Charles L., and Rafe Mazzeo. Wright-Fisher Geometry. Princeton University Press, 2017. http://dx.doi.org/10.23943/princeton/9780691157122.003.0002.
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This chapter introduces the geometric preliminaries needed to analyze generalized Kimura diffusions, with particular emphasis on Wright–Fisher geometry. It begins with a discussion of the natural domains of definition for generalized Kimura diffusions: polyhedra in Euclidean space or, more generally, abstract manifolds with corners. Amongst the convex polyhedra, the chapter distinguishes the subclass of regular convex polyhedra P. P is a regular convex polyhedron if it is convex and if near any corner, P is the intersection of no more than N half-spaces with corresponding normal vectors that are linearly independent. These definitions establish that any regular convex polyhedron is a manifold with corners. The chapter concludes by defining the general class of elliptic Kimura operators on a manifold with corners P and shows that there is a local normal form for any operator L in this class.
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Yacovazzi, Cassandra L. Escaped Nuns. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780190881009.001.0001.
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Just five weeks after its publication in January 1836, Awful Disclosures of the Hotel Dieu Nunnery sold over 20,000 copies. By “escaped nun,” Maria Monk, the book provided a shocking exposé of convent life, from licentious priests to tortured nuns to infanticide. Despite Maria Monk’s unveiling as an imposter, her book went on to become the second bestseller before the Civil War, after Uncle Tom’s Cabin. Far from representing a curious aberration, Monk’s book was part of a larger phenomenon, involving riots, propaganda, and politics. The campaign against convents was intimately connected with cultural concerns regarding reform, religion, immigration, and in particular the role of women in the republic. At a time when concern for “female virtue” consumed many Americans, nuns were a barometer of attitudes toward women. The veiled nun stood as the inversion of the true woman, needed to sustain the purity of the nation. She was a captive for a foreign foe, a fallen woman, a “white slave,” and a “foolish virgin.” In the first half of the nineteenth century, ministers, vigilantes, politicians, and writers, both male and female, crafted this image of the nun, locking arms against convents. The result was a far-reaching antebellum movement that would shape perceptions of nuns and women more broadly in America.
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Marcus, Smith, and Leslie Nico. Part IV Intangible Property that is Incapable of Transfer, 24 Personal Obligations. Oxford University Press, 2018. http://dx.doi.org/10.1093/law/9780198748434.003.0024.
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This chapter focuses on personal obligations. As has been described, one of the reasons contractual burdens are generally unassignable is because the beneficiary of the promise cannot, without his consent, be deprived of his rights as against his contractual counterparty. Here the concern is with the converse situation, where the beneficiary of a right wishes to transfer that right to someone else. The chapter then considers the reasons for the rule that a personal contractual obligation should not be assignable to a third party, analyses the test established by the relevant case law for determining whether a particular obligation is indeed a personal obligation, and sets out a number of the ways in which this test has been applied to specific factual scenarios.
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Ali, Muna. “Pure/True” Islam versus “Cultural” Islam. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780190664435.003.0004.
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This chapter examines the salient idea of a “pure/true” Islam as compared to a presumably “cultural” Islam. It argues that this narrative frame has multiple stories and meanings woven into it by Muslims and non-Muslims alike. Those Muslims drawing on it come from across the ideological spectrum, in groups labeled as “fundamentalists/Islamists,” “modernists,” “traditionalists,” and “secularists.” This chapter explores how this narrative speaks to fundamental questions about the definition of religion in general and to the anthropology of Islam in particular. Are there one or multiples islam(s), and who decides which is pure or true? It shows that younger generations of Muslim Americans, as well as many converts to Islam, invoke this narrative to argue that immigrant Muslim Americans’ understanding and practice of the religion is colored by their “back-home culture,” which privileges certain norms and traditions and relegates anything different, especially Western, to the category of un-Islamic.
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Regalado, Samuel O. The New Bushido. University of Illinois Press, 2017. http://dx.doi.org/10.5406/illinois/9780252037351.003.0002.
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This chapter examines the emergence of baseball within the changing political landscapes in both Japan and the United States, with an emphasis on the former. In particular, it explores baseball's origins in Japan and how it had come to be accepted during the Meiji era—a time when the nation took on new ideological approaches and sought to modernize and engage with the wider world. Baseball had landed in Japan equipped with all of the proper ingredients—patriotism, industrial productivity, and modernization—to support the reform mentality of the Meiji leaders. Moreover, American promoters of baseball tirelessly reminded potential converts of the game's democratic values. And most importantly, here was a Western activity that seemingly posed no threat to Japanese tradition.
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Wilkinson, Sam, and Charles Fernyhough. When Inner Speech Misleads. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198796640.003.0010.
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This chapter examines whether and when the experience of inner speech can be inaccurate and thereby mislead the subject. It presents a view about the representational content of speech experience generally and then applies it to inner speech in particular. On such a view, speech experience typically presents us with far more than simply the low-level acoustic properties of speech: it conveys the relevant mental states of the (actual or hypothetical) speaker. Similarly, inner speech presents inner speakers with their own mental states. In light of this, inner speech can mislead either by presenting the subject with mental states they do not in fact have, or by presenting these mental states as belonging to another agent. The chapter reflects on the sorts of contexts in which either of these could occur.
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Chi, Sang, and Emily Moberg Robinson, eds. Voices of the Asian American and Pacific Islander Experience. ABC-CLIO, LLC, 2012. http://dx.doi.org/10.5040/9798216032991.
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This unique work presents an extraordinary breadth of contemporary and historical views on Asian America and Pacific Islanders, conveyed through the voices of the men and women who lived these experiences over more than 150 years. In 1848, the "First Wave" of Asian immigration arrived in the United States. By the first decade of the 21st century, Asian Americans were the nation's fastest growing racial group. Through a far-ranging array of primary source documents,Voices of the Asian American and Pacific Islander Experienceshares what it was like for these diverse peoples to live and work in the United States, for better and for worse. Organized chronologically by ethnicity, the book covers a panoply of ethnic groups, including recent Asian immigrants and mixed race/mixed heritage Asian Americans. There is also a topical section that showcases views on everything from politics to class to gender dynamics, underscoring that the Asian American population is not—nor has it ever been—monolithic. In choosing material, the editors strove to make the volume as comprehensive as possible. Thus, readers will discover documents written by transnational, adopted, and homosexual Asian Americans, as well as documents written from particular religious positions.
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Vera, Alejandro. The Sweet Penance of Music. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780190940218.001.0001.
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This book provides a fresh, comprehensive view of the musical life and its cultural context in Santiago, Chile, from its foundation in 1541 to the end of the colonial period, roughly in 1810. Combining the study of archival documents, secondary sources, and music scores, it deals with different aspects of musical life in the cathedral (Chapter 1), convents and monasteries (Chapter 2), private houses (Chapter 3), and public spaces (Chapter 4), considering, as well, the life and function of musicians as crucial agents in the music field (Chapter 5). Despite its focus on a particular city of Latin America, it raises this issue from a broad perspective that explores its links with other urban centers (especially Lima), within the globalizing framework of the colonial system. The idea of music as a “sweet penance,” belonging to a nun harpist in a convent of Santiago at the end of the eighteenth century, gives rise to the consideration of duality as an essential trait of the period and its music.
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De Souza, Jonathan. Music at Hand. Oxford University Press, 2017. http://dx.doi.org/10.1093/acprof:oso/9780190271114.001.0001.
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Musical instruments ground players’ actions and the sounds they create. Yet this book further claims that instruments mediate perception and imagination. Practicing an instrument builds bodily skills, while also fostering auditory-motor connections in players’ brains. These intersensory links reflect the ways that a particular instrument converts action into sound, the ways that it coordinates tonal and physical space. Reactivated in various ways, these connections can influence instrumentalists’ listening, improvisation, and composition. To investigate these effects, the book engages both classical and popular styles, from Bach to electronic music, from Beethoven to the blues. It uses Lewinian transformational theory to model instrumental interfaces and to analyze patterns of body-instrument interaction. Though based in music theory and analysis, the book also draws on psychology, including cognitive neuroscience, and the phenomenological philosophy of Maurice Merleau-Ponty and Martin Heidegger. Ultimately, it argues that music cognition is not simply embodied; it is also conditioned by musical technology.
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Duffley, Patrick. Linguistic Meaning Meets Linguistic Form. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780198850700.001.0001.
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This book steers a middle course between two opposing conceptions that currently dominate the field of semantics, the logical and cognitive approaches. It brings to light the inadequacies of both frameworks, and argues along with the Columbia School that linguistic semantics must be grounded on the linguistic sign itself and the meaning it conveys across the full range of its uses. The book offers 12 case studies demonstrating the explanatory power of a sign-based semantics, dealing with topics such as complementation with aspectual and causative verbs, control and raising, wh- words, full-verb inversion, and existential-there constructions. It calls for a radical revision of the semantics/pragmatics interface, proposing that the dividing-line be drawn between semiologically-signified notional content (i.e. what is linguistically encoded) and non-semiologically-signified notional content (i.e. what is not encoded but still communicated). This highlights a dimension of embodiment that concerns the basic design architecture of human language itself: the ineludable fact that the fundamental relation on which language is based is the association between a mind-engendered meaning and a bodily produced sign. It is argued that linguistic analysis often disregards this fact and treats meaning on the level of the sentence or the construction, rather than on that of the lower-level linguistic items where the linguistic sign is stored in a stable, permanent, and direct relation with its meaning outside of any particular context. Building linguistic analysis up from the ground level provides it with a more solid foundation and increases its explanatory power.
Book chapters on the topic "Non convexes particules"
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Wu, Haoze, Aleksandar Zeljić, Guy Katz, and Clark Barrett. "Efficient Neural Network Analysis with Sum-of-Infeasibilities." In Tools and Algorithms for the Construction and Analysis of Systems. Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-99524-9_8.
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AbstractInspired by sum-of-infeasibilities methods in convex optimization, we propose a novel procedure for analyzing verification queries on neural networks with piecewise-linear activation functions. Given a convex relaxation which over-approximates the non-convex activation functions, we encode the violations of activation functions as a cost function and optimize it with respect to the convex relaxation. The cost function, referred to as the Sum-of-Infeasibilities (SoI), is designed so that its minimum is zero and achieved only if all the activation functions are satisfied. We propose a stochastic procedure, , to efficiently minimize the SoI. An extension to a canonical case-analysis-based complete search procedure can be achieved by replacing the convex procedure executed at each search state with . Extending the complete search with achieves multiple simultaneous goals: 1) it guides the search towards a counter-example; 2) it enables more informed branching decisions; and 3) it creates additional opportunities for bound derivation. An extensive evaluation across different benchmarks and solvers demonstrates the benefit of the proposed techniques. In particular, we demonstrate that SoI significantly improves the performance of an existing complete search procedure. Moreover, the SoI-based implementation outperforms other state-of-the-art complete verifiers. We also show that our technique can efficiently improve upon the perturbation bound derived by a recent adversarial attack algorithm.
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García-Sancho, Miguel, and James Lowe. "Making Reference Genomes Useful: Annotation." In A History of Genomics across Species, Communities and Projects. Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-06130-1_6.
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AbstractThrough examining how the reference genomes of yeast, human and pig were annotated, in this chapter we further identify how the involvement or non-involvement of particular communities in the creation of a reference genome can affect the nature of the product. We therefore continue to distinguish the qualities of separate reference genomes, which are otherwise rendered as commensurate and equivalent objects by data repositories such as RefSeq. In doing so, we present alternative historical trajectories to the narrative centred around the Human Genome Project. In particular, this chapter conveys how the relationship between pig genomicists and a key annotation group at the Sanger Institute shaped the direction of annotation at that institution. This led the Sanger Institute group to formulate a new way of conducting ‘community annotation’, an approach that had previously been performed in a limited and attenuated fashion, for example at the jamboree meetings of Celera Genomics.
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Treis, Yvonne, and Martine Vanhove. "Converb constructions and clause chaining in Cushitic." In Clause Chaining in the Languages of the World. Oxford University PressOxford, 2024. https://doi.org/10.1093/oso/9780198870319.003.0028.
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Abstract This chapter describes the morphology and syntax of converbs in eleven Cushitic languages, with a special focus on Beja and Kambaata. Cushitic converbs are used in clause chaining function, but chains are considerably shorter than in e.g. Papuan languages. In some languages, converbal clauses qualify as embedded clauses. Across the Cushitic family, converbs display considerable formal and functional variation. On a morphological cline of finiteness, converbs range from strictly non-finite to partially finite forms. Between one and six converb types, with different degrees of semantic specialization, are distinguished in individual languages. Only in one genetic subgrouping are converbs marked for switch-reference. The final part of this chapter discusses the use of converbs beyond clause combining and provides examples of lexicalization and grammaticalization, in particular as part of complex predicates.
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Plummer, Marjorie Elizabeth. "The Fight for Keys." In Stripping the Veil. Oxford University Press, 2022. http://dx.doi.org/10.1093/oso/9780192857286.003.0003.
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Chapter 2 shows how secular convent reform policies evolved between 1525 and the mid-1540s in reaction to the violence against convents and nuns during the 1525 Peasants’ War. It explores the emerging convent reform policies after 1525 until the Schmalkaldic War (1546–47), when secular authorities sought to confiscate and close convents in non-violent ways. Changes from convent destruction to convent reform also occurred when reformers and secular rulers made concessions on monasticism in response to imperial pressure and legal changes on property law. In particular, the principle of freedom from compulsion (force) in matters of conscience, espoused by both Martin Luther and Emperor Charles V, and the legal protection of convent property in imperial law altered how secular officials approached convent reform. Most secular authorities grudgingly allowed local convents to remain open, although most refused to permit convent congregations to admit new novices.
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Katz, Larissa. "When it is Wrong to Hold On." In Oxford Studies in Private Law Theory: Volume I. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780198851356.003.0002.
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Private law as a rule presumes we hold on to what we have. A principle of non-derogation from the grant seems to be at odds with this: far from presuming that grantors part with the least they could on making a grant, the principle generates the presumption that a grantor conveys all she has to give. In this paper I explain the principle of non-derogation from the grant in terms of an appointment of a successor to a position of authority, and so the ideal of a grant as a conveyance of the full authority associated with that position. Voluntarist as to whether a legal power is exercised, the law’s approach is rationalist as to the effects of its exercise, making sense of particular grants in terms of the ideal of a grant. This explains both why there is a strong presumption against change in our relations with others (and the demand for juridical reasons to explain any change) and at the same time, once rebutted, a presumption that the grant conveys what is reasonably necessary for it to operate as the appointment of another fully to that position of authority.
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Luo, Kangyang, Kunkun Zhang, Shengbo Zhang, Xiang Li, and Ming Gao. "Decentralized Local Updates with Dual-Slow Estimation and Momentum-Based Variance-Reduction for Non-Convex Optimization." In Frontiers in Artificial Intelligence and Applications. IOS Press, 2023. http://dx.doi.org/10.3233/faia230445.
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Decentralized learning (DL) has recently employed local updates to reduce the communication cost for general non-convex optimization problems. Specifically, local updates require each node to perform multiple update steps on the parameters of the local model before communicating with others. However, most existing methods could be highly sensitive to data heterogeneity (i.e., non-iid data distribution) and adversely affected by the stochastic gradient noise. In this paper, we propose DSE-MVR to address these problems. Specifically, DSE-MVR introduces a dual-slow estimation strategy that utilizes the gradient tracking technique to estimate the global accumulated update direction for handling the data heterogeneity problem; also for stochastic noise, the method uses the mini-batch momentum-based variance-reduction technique. We theoretically prove that DSE-MVR can achieve optimal convergence results for general non-convex optimization in both iid and non-iid data distribution settings. In particular, the leading terms in the convergence rates derived by DSE-MVR are independent of the stochastic noise for large-batches or large partial average intervals (i.e., the number of local update steps). Further, we put forward DSE-SGD and theoretically justify the importance of the dual-slow estimation strategy in the data heterogeneity setting. Finally, we conduct extensive experiments to show the superiority of DSE-MVR against other state-of-the-art approaches. We provide our code here: https://anonymous.4open.science/r/DSE-MVR-32B8/.
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"Jerold S. Auerbach, Print to Fit: The New York Times, Zionism and Israel 1896–2016. Boston: Academic Studies Press, 2019. xii + 309 pp." In No Small Matter, edited by Anat Helman. Oxford University Press, 2021. http://dx.doi.org/10.1093/oso/9780197577301.003.0028.
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This chapter examines Jerold S. Auerbach's Print to Fit (2019). In this book, Auerbach charges that the New York Times consistently slanted its treatment of Israel in ways that discredited its struggle for survival and instead sympathized with the enemies of Zionism. Having assiduously combed through close to a century of articles, editorials, and op-ed pieces, Auerbach has discovered, especially in recent decades, a “preoccupation with Palestinian victimization — even when Israelis were the victims.” Print to Fit is especially harsh in its treatment of two of the Times' stars, the late Anthony Lewis and Thomas L. Friedman for having so often conveyed their own disenchantment with what they held to be the moral and political failings of Israel — in particular, the extension of Jewish settlements into the West Bank. Written from the political periphery of American Jewish life, Print to Fit risks overstating its case by simplifying it.
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Jetpurwala, Abdulkadeer M., Nilesh Rathi, and Ritesh Kalaskar. "Traumatic Injuries to Anterior Teeth: Etiology, Predisposing Factors and Examination." In Illustrated Pediatric Dentistry - Part 3. BENTHAM SCIENCE PUBLISHERS, 2023. http://dx.doi.org/10.2174/9789815080803123030014.
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Traumatic injuries are commonly seen in children. There are various causes and factors that make an individual or a particular tooth more susceptible to traumatic injury. Owing to factors like early fine motor development of infants and toddlers, participation in sports and other physical activities, accidental and non-accidental injuries or common reasons, children may suffer from dental trauma. Many facial types like convex facial profiles, class malocclusions and malposition of teeth also make the teeth prone to trauma. This section describes the etiologic and predisposing factors and sketches an outline for a detailed examination of traumatic dental injuries.
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Borsay, Peter. "Biography." In The Image of Georgian Bath, 1700–2000. Oxford University PressOxford, 2000. http://dx.doi.org/10.1093/oso/9780198202653.003.0004.
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Abstract The previous section of this book sought to demonstrate that the image of Georgian Bath is something which has been created and re-created, interpreted and re-interpreted; in other words, that it has a genesis and a history. This section will focus on the image as an artefact, with a specific formal content, expressed through particular media. To take the analogy of a painting. What is produced, at least in non-abstract art, has a recognizable subject-matter—such as people, buildings, and natural features—and this matter is conveyed through various media, like oils, watercolours, and inks. Chapters 4 to 6 will explore the subject-matter or form of Bath’s Georgian image, Chapter 7 the materials or media used to transmit it.
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Butchvarov, Panayot. "The Untruth And The Truth Of Skepticism." In Skepticism About The External World. Oxford University PressNew York, NY, 1998. http://dx.doi.org/10.1093/oso/9780195117196.003.0007.
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Abstract We are now ready to attempt another answer to the skeptic, one based on the preceding considerations regarding the concept of reality. Can what I have called the particular (nonmodal epistemic) question, namely, Do we know or at least have evidence, in some particular perceptual situation, that what we perceive is a real material object? be given a nonskeptical answer, just as in chapter 4 I gave a nonskeptical answer to the general (non modal epistemic) question, namely, Do we know or at least have evidence that material objects exist? If it can, then we would also have a second nonskeptical answer to the general question, since a nonskeptical answer to the particular question entails a nonskeptical answer to the general question, though not vice versa. Thus my argument in chapter 4 in favor of the latter would receive welcome supplementation. But, as we shall see, we would still need that argument at a crucial point in our search in this chapter for a complete nonskeptical answer to the particular question. The fact is that both answers are needed. There is no circularity here, since the argument in chapter 4 is independent of the argument to be offered in this chapter. It’s just that the converse is not quite the case.
Conference papers on the topic "Non convexes particules"
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Everaere, Patricia, Sébastien Konieczny, and Ramón Pino Pérez. "Weighted Merging Operators: Product, Utility-based Operators and Egalitarianism." In 21st International Conference on Principles of Knowledge Representation and Reasoning {KR-2023}. International Joint Conferences on Artificial Intelligence Organization, 2024. http://dx.doi.org/10.24963/kr.2024/31.
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We propose new operators for weighted propositional belief merging operators. We introduce distance-based operators that use the product as aggregation function. In social choice theory, the product, called the Nash welfare function, is known to be a more equitable social welfare function than the classical utilitarian welfare function (based on a sum). We study which properties are satisfied by the obtained corresponding weighted merging operators. In particular, we show that, unlike the Nash welfare function, distance-based operators using the product do not satisfy the Pigou-Dalton property. Then, we introduce a new family of weighted merging operators, which we call utility-based weighted merging operators, where the utility is roughly the converse of a distance for distance-based operators. For most well-known distance-based operators, it is easy to find the corresponding utility-based merging operators. But an interesting result is that the utility-based weighted merging operator based on the product does not correspond to any standard distance-based weighted merging operator, and this operator satisfies the Pigou-Dalton property.
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Morel, Yannick, and Alexander Leonessa. "Observer-Based Output Feedback Control of Nonlinear Systems Non-Affine in the Unmeasured States." In ASME 2009 Dynamic Systems and Control Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/dscc2009-2620.
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The presented work addresses the output feedback control problem for a large class of nonlinear systems. The control strategy shares similarities to separation-based algorithms commonly found in the literature, in the sense that the control problem is solved using an observer-predictor, in conjunction with a state feedback control law. The approach however distinguishes itself in significant ways. In particular, the control algorithm is not designed to control the actual system’s output, as is usually the case in separation-based approaches, but it is rather designed to control the output of the observer-predictor. The latter is designed to ensure that, for any admissible control signal, its output converges to a neighborhood of the corresponding output of the real system. The observer-predictor is thus used to indirectly control the real system. Results of numerical simulations are provided to illustrate performance of the obtained control algorithm.
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Suilen, Marnix, Nils Jansen, Murat Cubuktepe, and Ufuk Topcu. "Robust Policy Synthesis for Uncertain POMDPs via Convex Optimization." In Twenty-Ninth International Joint Conference on Artificial Intelligence and Seventeenth Pacific Rim International Conference on Artificial Intelligence {IJCAI-PRICAI-20}. International Joint Conferences on Artificial Intelligence Organization, 2020. http://dx.doi.org/10.24963/ijcai.2020/569.
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We study the problem of policy synthesis for uncertain partially observable Markov decision processes (uPOMDPs). The transition probability function of uPOMDPs is only known to belong to a so-called uncertainty set, for instance in the form of probability intervals. Such a model arises when, for example, an agent operates under information limitation due to imperfect knowledge about the accuracy of its sensors. The goal is to compute a policy for the agent that is robust against all possible probability distributions within the uncertainty set. In particular, we are interested in a policy that robustly ensures the satisfaction of temporal logic and expected reward specifications. We state the underlying optimization problem as a semi-infinite quadratically-constrained quadratic program (QCQP), which has finitely many variables and infinitely many constraints. Since QCQPs are non-convex in general and practically infeasible to solve, we resort to the so-called convex-concave procedure to convexify the QCQP. Even though convex, the resulting optimization problem still has infinitely many constraints and is NP-hard. For uncertainty sets that form convex polytopes, we provide a transformation of the problem to a convex QCQP with finitely many constraints. We demonstrate the feasibility of our approach by means of several case studies that highlight typical bottlenecks for our problem. In particular, we show that we are able to solve benchmarks with hundreds of thousands of states, hundreds of different observations, and we investigate the effect of different levels of uncertainty in the models.
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Kumabe, Soh, and Takanori Maehara. "Convexity of b-matching Games." In Twenty-Ninth International Joint Conference on Artificial Intelligence and Seventeenth Pacific Rim International Conference on Artificial Intelligence {IJCAI-PRICAI-20}. International Joint Conferences on Artificial Intelligence Organization, 2020. http://dx.doi.org/10.24963/ijcai.2020/37.
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The b-matching game is a cooperative game defined on a graph. The game generalizes the matching game to allow each individual to have more than one partner. The game has several applications, such as the roommate assignment, the multi-item version of the seller-buyer assignment, and the international kidney exchange. Compared with the standard matching game, the b-matching game is computationally hard. In particular, the core non-emptiness problem and the core membership problem are co-NP-hard. Therefore, we focus on the convexity of the game, which is a sufficient condition of the core non-emptiness and often more tractable concept than the core non-emptiness. It also has several additional benefits. In this study, we give a necessary and sufficient condition of the convexity of the b-matching game. This condition also gives an O(n log n + m α(n)) time algorithm to determine whether a given game is convex or not, where n and m are the number of vertices and edges of a given graph, respectively, and α(・) is the inverse-Ackermann function. Using our characterization, we also give a polynomial-time algorithm to compute the Shapley value of a convex b-matching game.
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Hawthorn, A., D. Groves, and G. Osunjaye. "Real-Time Downhole Data Transforms the Efficiency and Safety of Tubing Conveyed Deepwater Multizone Perforation Operations." In Offshore Technology Conference. OTC, 2024. http://dx.doi.org/10.4043/35165-ms.
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Abstract Tubing conveyed perforating (TCP) is an essential part of the completion in many fields in the Gulf of Mexico and elsewhere. However, there are many risks associated with the operation which can cause significant non-productive time (NPT). These are generally to do with not having visibility of what is actually happening downhole below closed multistage valves. Until recently there has been no real-time data available to understand this. In particular, the pressure reading below the closed valve has not been known. Different operators perforate in different ways as regards the pressure balance in the well, some prefer to perforate over balanced and some under balanced. Before the valve is opened the well is "balanced" to what is assumed to be the pressure regime below the valve after perforation. If this assumption of the pressure is incorrect then the well can either go on losses or can induce an influx into the well depending on whether you are overbalanced or underbalanced to the now perforated zones. This is further exacerbated if you are attempting to perforate several zones in the same run with different zones being at differing pressures in relations to each other. This can cause crossflow and backflow between the various zones making an understanding of what the pressure regime is likely to be more complicated. To counteract this then often in multi-zone wells each zone may be perforated separately with a follow up deburring run in between each perforation run. This method particularly on deepwater vessels can be time consuming and therefore costly, whilst still not knowing exactly what the pressure is under the closed valve after perforation. This paper will demonstrate how an acoustic telemetry and measurement system can communicate data in real-time below the closed valve and then back along the drill pipe to allow for safely managing the well if there is an influx. This allowed multiple zones to be safely perforated in the same run. Additionally, the system can be used for improving the torque and drag models for the subsequent lower completions runs which are difficult to manage in multi zone completions. We will show with data from a sequence of wells how this was introduced and implemented into the tubing conveyed perforating operations eliminating multiple runs and derisking the operations through the use of real-time downhole data. In particular how the processes were changed to deal with influxes over the campaign of wells.
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Stark, Henry, and Peyma Oskoui-Fard. "Image reconstruction in tomography using convex projections." In OSA Annual Meeting. Optica Publishing Group, 1986. http://dx.doi.org/10.1364/oam.1986.mr4.
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The method of projections onto convex sets (POCS) has been widely used in image recovery and synthesis problems but it has never been used as an actual reconstruction algorithm in tomography. Yet POCS offers certain advantages over methods such as convolution backprojection or direct Fourier inversion. What are these advantages? First, POCS does not require a particular data gathering geometry (e.g., parallel beam or fan beam projections); it can be used with any arbitrary set of projection data. Second, POCS furnishes a systematic technique for incorporating a priori information about the image. It is interesting to note that when POCS is used in its most primitive mode, i.e., the only constraints are those imposed by the line-integral projections, it becomes the well-known ART algorithm. We describe how POCS is used to reconstruct images in tomography and present computer simulations to verify the feasibility of the procedure.
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Gutman, Georgy, Kevin Parker, James L. Wood, and Richard Watts. "Multilayer Performance for Soft X-ray Schwarzchild Optics." In Soft X-Ray Projection Lithography. Optica Publishing Group, 1992. http://dx.doi.org/10.1364/sxray.1992.tub4.
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One of the most important requirements for soft x-ray optics is high normal incidence reflectivity. But to ensure a high throughput optical system, Schwarzchild objectives in particular, it is not only necessary to fabricate multilayer coatings with the highest possible reflectivity but to achieve the designed d-spacing uniformity/grading and match the d-spacings of the concave and convex mirrors. The latter is especially important for high throughput multi-mirror lithography optical schemes.[1]
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Jiang, Qiang, and Michael Ng. "Robust Low-Tubal-Rank Tensor Completion via Convex Optimization." In Twenty-Eighth International Joint Conference on Artificial Intelligence {IJCAI-19}. International Joint Conferences on Artificial Intelligence Organization, 2019. http://dx.doi.org/10.24963/ijcai.2019/368.
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This paper considers the problem of recovering multidimensional array, in particular third-order tensor, from a random subset of its arbitrarily corrupted entries. Our study is based on a recently proposed algebraic framework in which the tensor-SVD is introduced to capture the low-tubal-rank structure in tensor. We analyze the performance of a convex program, which minimizes a weighted combination of the tensor nuclear norm, a convex surrogate for the tensor tubal rank, and the tensor l1 norm. We prove that under certain incoherence conditions, this program can recover the tensor exactly with overwhelming probability, provided that its tubal rank is not too large and that the corruptions are reasonably sparse. The number of required observations is order optimal (up to a logarithm factor) when comparing with the degrees of freedom of the low-tubal-rank tensor. Numerical experiments verify our theoretical results and real-world applications demonstrate the effectiveness of our algorithm.
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Vanem, Erik. "On the Influence of Environmental Contour Method in Estimating Extreme Structural Response." In ASME 2017 36th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/omae2017-61047.
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Environmental contours are often applied in probabilistic structural reliability analysis in order to identify extreme environmental conditions that may give rise to extreme loads and responses. The perhaps most common way of establishing such environmental contours are based on the Rosenblatt transform and the IFORM approximation (Inverse First Order Reliability Method), but recently an alternative approach based on direct Monte Carlo simulations with importance sampling has been proposed. A recent comparison study revealed that there might be rather large differences in certain parts of the contours and for certain joint environmental models. In particular, the alternative contour method yields convex contours by design, whereas the traditional contours may be convex or non-convex. In this paper, comparison studies that include applications on a few structural examples are presented. Comparing the contours with known response surfaces, one may investigate how large the differences between the contour methods may be, and compare this to the correct extreme response estimated by simulation studies. These case studies clearly illustrate the influence of the environmental contour calculation method on the estimated extreme response. Whereas the different methods yield comparable results for some structural problems, they may give very different estimates of the extreme response for other. It is demonstrated that in certain cases, the estimates from some of the contour methods are highly conservative, whereas they in other cases might be very optimistic. The reason for these results are discussed and some requirements on the response functions for obtaining conservative estimates will be stated.
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Bailey, Mike, Dru Clark, and John Rapp. "A 3D Graphical Method for Interactively Determining the Vertical Convexity of Designs to be Molded." In ASME 2007 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/detc2007-35165.
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The Center for 3D Visualization Hardcopy (C3VH) was initiated in 1995 as a web-accessible facility to create 3D physical models. By making such prototyping hardware easy to access and the geometry files easy to check and correct, we have been able to drive the model-making process into the less traditional manufacturing area of scientific visualization. But, there have been requests for many copies of a single model. As “rapid” prototyping is actually quite slow and unsuitable for mass production, these requests have required us to enter the world of molding for mass production. As part of this, we have needed to quickly determine how feasible it is to mold a particular model. This paper shows an interactive OpenGL method that we developed for determining the optimal orientation for a model’s parting line. By using a novel OpenGL stencil buffer technique, the user can reorient the model on the screen, and see from the colors in the display how vertically convex it is in that orientation, and in what parts of the model it is not vertically convex.
Reports on the topic "Non convexes particules"
1
Hellström, Anders. How anti-immigration views were articulated in Sweden during and after 2015. Malmö University, Malmö Institute for Studies of Migration, Diversity and Welfare (MIM), 2021. http://dx.doi.org/10.24834/isbn.9789178771936.
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The development towards the mainstreaming of extremism in European countries in the areas of immigration and integration has taken place both in policy and in discourse. The harsh policy measures that were implemented after the 2015 refugee crisis have led to a discursive shift; what is normal to say and do in the areas of immigration and integration has changed. Anti-immigration claims are today not merely articulated in the fringes of the political spectrum but more widely accepted and also, at least partly, officially sanctioned. This study investigates the anti-immigration claims, seen as (populist) appeals to the people that centre around a particular mythology of the people and that are, as such, deeply ingrained in national identity construction. The two dimensions of the populist divide are of relevance here: The horizontal dimension refers to articulated differences between "the people", who belong here, and the "non-people" (the other), who do not. The vertical dimension refers to articulated differences between the common people and the established elites. Empirically, the analysis shows how anti-immigration views embedded in processes of national myth making during and after 2015 were articulated in the socially conservative online newspaper Samtiden from 2016 to 2019. The results indicate that far-right populist discourse conveys a nostalgia for a golden age and a cohesive and homogenous collective identity, combining ideals of cultural conformism and socioeconomic fairness.
2
Katzenberger, John, and Susan Joy Hassol. Elements of Change Series: Characterizing and Communicating Scientific Uncertainty. Aspen Global Change Institute, 1997. http://dx.doi.org/10.69925/kncp4820.
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Characterizing uncertainty is a major issue in all scientific discourse, but it is of particular importance in climate change research. Widely publicized climate change findings, such as the periodic reports authored by the Intergovernmental Panel on Climate Change (IPCC), must find precision in their language so that the published findings are neither understated nor exaggerated and can be taken seriously by policymakers, the media, and the public. This Elements of Change report tackles this problem by summarizing the proceedings of a 1996 AGCI meeting that was convened to discuss how uncertainty is communicated in reports such as the one put out by the IPCC. In attendance were climate change researchers, policy analysts, and media experts, and this report addresses scientific, media, and policy related issues pertaining to uncertainty.
3
Hrynick, Tabitha, and Megan Schmidt-Sane. Roundtable Report: Discussion on mpox in DRC and Social Science Considerations for Operational Response. Institute of Development Studies, 2024. http://dx.doi.org/10.19088/sshap.2024.014.
Full textAbstract:
On 28 May 2024, the Social Science in Humanitarian Action Platform (SSHAP) organised a roundtable discussion on the mpox (formerly known as monkeypox) outbreak which has been spreading in the Democratic Republic of the Congo (DRC) since early 2023.1 The objective was to appraise the current situation, with a particular focus on social science insights for informing context-sensitive risk communication and community engagement (RCCE) and wider operational responses. The roundtable was structured into two sessions: 1) an overview of the situation in DRC, including the current knowledge of epidemiology and 2) contextual considerations for response. This was followed by an hour-long panel discussion on operational considerations for response. Each session was initiated by a series of catalyst presentations followed by a question-and-answer session (Q&A). Details of the agenda, speakers and discussants can be found below. Despite estimates that less than 10% of suspected cases in DRC are being laboratory screened, the country is currently reporting the highest number of people affected by mpox in sub-Saharan Africa. It is notable that clade 1 of mpox is linked to this outbreak, which results in more severe disease and a higher fatality rate. While early cases of mpox were reported to be in gay, bisexual, and other men who have sex with men (GBMSM), the disease is now being detected more widely in DRC. The majority of those affected are children (up to 70% by some estimates2), which is a cause for concern. The outbreak is occurring on top of an overall high burden of disease and significant challenges to the health system and humanitarian interventions. The apparently heterogeneous picture of mpox across DRC – affecting different geographies and population groups – is shaped in part by social, economic and political factors. For instance, in South Kivu, accounts indicate that transmission via intimate and sexual contact is significant in mining areas, with an estimated one third of cases of disease reported in female sex workers. This raises questions about transactional sex and related stigma in these areas, as well as the implications of cross-border mobility linked to mining livelihoods for the spread of disease. A history of conflict and militia activity has additional implications for humanitarian intervention and is a factor in uptake and implementation of control strategies such as vaccination. Severe limitations in government health facilities in remote areas and a plural landscape of biomedical and non-biomedical providers are additional factors to consider for patterns of care-seeking and the timely provision of biomedical care. The limited reach of formal healthcare, including surveillance, makes it difficult to estimate the extent of cases and control disease spread through conventional epidemiological strategies. There are likely further challenges in accessing less visible populations such as GBMSM, as research in Nigeria has suggested.3,4 These complex contextual realities raise significant questions for mpox response. The roundtable convened a diverse range of expertise to offer perspectives from existing research and knowledge, with an emphasis on social science evidence. This roundtable report presents a synthesised version of the roundtable discussion with additional context as needed.
4
Whitham, Steven A., Amit Gal-On, and Tzahi Arazi. Functional analysis of virus and host components that mediate potyvirus-induced diseases. United States Department of Agriculture, 2008. http://dx.doi.org/10.32747/2008.7591732.bard.
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The mechanisms underlying the development of symptoms in response to virus infection remain to be discovered in plants. Insight into symptoms induced by potyviruses comes from evidence implicating the potyviral HC-Pro protein in symptom development. In particular, recent studies link the development of symptoms in infected plants to HC-Pro's ability to interfere with small RNA metabolism and function in plant hosts. Moreover, mutation of the highly conserved FRNK amino acid motif to FINK in the HC-Pro of Zucchini yellow mosaic virus (ZYMV) converts a severe strain into an asymptomatic strain, but does not affect virus accumulation in cucurbit hosts. The ability of this FINK mutation to uncouple symptoms from virus accumulation creates a unique opportunity to study symptom etiology, which is usually confounded by simultaneous attenuation of both symptoms and virus accumulation. Our goal was to determine how mutations in the conserved FRNK motif affect host responses to potyvirus infection in cucurbits and Arabidopsis thaliana. Our first objective was to define those amino acids in the FRNK motif that are required for symptoms by mutating the FRNK motif in ZYMV and Turnip mosaic virus (TuMV). Symptom expression and accumulation of resulting mutant viruses in cucurbits and Arabidopsis was determined. Our second objective was to identify plant genes associated with virus disease symptoms by profiling gene expression in cucurbits and Arabidopsis in response to mutant and wild type ZYMV and TuMV, respectively. Genes from the two host species that are differentially expressed led us to focus on a subset of genes that are expected to be involved in symptom expression. Our third objective was to determine the functions of small RNA species in response to mutant and wild type HC-Pro protein expression by monitoring the accumulation of small RNAs and their targets in Arabidopsis and cucurbit plants infected with wild type and mutant TuMV and ZYMV, respectively. We have found that the maintenance of the charge of the amino acids in the FRNK motif of HC-Pro is required for symptom expression. Reduced charge (FRNA, FRNL) lessen virus symptoms, and maintain the suppression of RNA silencing. The FRNK motif is involved in binding of small RNA species including microRNAs (miRNA) and short interfering RNAs (siRNA). This binding activity mediated by the FRNK motif has a role in protecting the viral genome from degradation by the host RNA silencing system. However, it also provides a mechanism by which the FRNK motif participates in inducing the symptoms of viral infection. Small RNA species, such as miRNA and siRNA, can regulate the functions of plant genes that affect plant growth and development. Thus, this binding activity suggests a mechanism by which ZYMVHC-Pro can interfere with plant development resulting in disease symptoms. Because the host genes regulated by small RNAs are known, we have identified candidate host genes that are expected to play a role in symptoms when their regulation is disrupted during viral infections. As a result of this work, we have a better understanding of the FRNK amino acid motif of HC-Pro and its contribution to the functions of HC-Pro, and we have identified plant genes that potentially contribute to symptoms of virus infected plants when their expression becomes misregulated during potyviral infections. The results set the stage to establish the roles of specific host genes in viral pathogenicity. The potential benefits include the development of novel strategies for controlling diseases caused by viruses, methods to ensure stable expression of transgenes in genetically improved crops, and improved potyvirus vectors for expression of proteins or peptides in plants.
5
Accelerating Digital Payments in Latin America and the Caribbean. Inter-American Development Bank, 2022. http://dx.doi.org/10.18235/0004256.
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Between the first and second quarters of 2020, e-commerce website traffic from five of the regions major markets increased by over 150%. The COVID-19 pandemic has pushed and pulled tens of thousands of businesses in the region to go digital. The impact and advantages of such digitalization are quite telling for small and medium-sized enterprises (SMEs) in particular. SMEs in LAC can diversify their customer base and reach 20 foreign markets when operating online, while those that operate offline can only reach from two to five. As todays digital economy becomes the norm, universal basic services such as education and medical care are also taking place online. Digital payments are critical to enabling this transformation at both domestic and cross-border levels. But many challenges still exist that preclude the broadening of digital payment use throughout the region from a lack of access, regulatory harmonization and affordable payment solutions, to a need for further public and private sector cooperation, consumer protections and an open, inclusive and interoperable payment ecosystem. In 2021, the World Economic Forum and the innovation laboratory of the Inter-American Development Bank, IDB Lab, jointly launched the Payments to Advance Growth for All (PAGA) initiative to address these challenges. This initiative has convened a diverse community of over 100 public and private sector representatives to explore, through dialogue, how to best unlock the true benefits of digital payments in LAC. As digital payments continue to thrive and drive financial inclusion and economic growth, we hope this paper will provide a timely snapshot of the most pressing issues and highlight the importance of public-private and private-private cooperation to advance digital payments for all in an open, inclusive and safe manner. * The opinions expressed in this work are those of the authors and do not necessarily reflect the views of the IDB, its Board of Directors or the countries they represent, nor of the MIF (IDB Lab) Donors Committee or the countries it represents.