An Object model for engineering design

Applications requiring sophisticated modeling techniques raise challenging issues to software designers. CAD/CAM and genetics are example of applications that call for powerful modeling techniques. Existing approaches seem limited in their ability to supports their demands. Relational database systems for example support only simple tables. The need to enhance their capabilities led to non-normalized relational data models. Object-oriented programming languages and databases propose new solutions to the problem of complex and composite object modeling and manipulation. Yet, severe shortcomings impede their practicability, e.g., their inability to model multiple object representations and complex semantic relationships. This paper is an informal overview of a data model called SHOOD implements sophisticated features, such as : o object persistence, multi-methods along a specific specialization hierarchy (which is independent of the class hierarchy), o sophisticated semantic relationships, e.g., dependency relationships between objects (which are totally independent of the composition relationship), o multiple object representations, allowing the users to manipulate the objects from several points of views simultaneously, o the systematic use of a powerful meta-object kernel, which is used to implement a reflexive architecture. The paper focuses on the last two issues

The nature and origin of heavy tails in retweet activity

WWW 2017 CompanionModern social media platforms facilitate the rapid spread of information online. Modelling phenomena such as social contagion and information diffusion are contingent upon a detailed understanding of the information-sharing processes. In Twitter, an important aspect of this occurs with retweets, where users rebroadcast the tweets of other users. To improve our understanding of how these distributions arise, we analyse the distribution of retweet times. We show that a power law with exponential cutoff provides a better fit than the power laws previously suggested. We explain this fit through the burstiness of human behaviour and the priorities individuals place on different tasks.Peter Mathews, Lewis Mitchell, Giang Nguyen, Nigel Bea

Representation de connaissances dynamiques dans SHERPA

On decrit un modele de representation des connaissances developpe dans le cadre du projet Sherpa. L'objectif du projet est de definir, mettre en oeuvre et experimenter un systeme de representation de connaissances dynamiques base sur un modele a objets. Sherpa est un projet commun Imag et Inria. Les racines du modele se trouvent en intelligence artificielle, dans le domaine des bases de donnees orientees-objet et en CAO. Le modele presente ici integre en effet des concepts issus des langages de frames, des langages orientes-objets et repond a certains besoins d'applications qui doivent gerer des objets evolutifs. On presente les concepts de base du modele, puis la semantique et la mise en oeuvre de l'heritage. On decrit ensuite la notion de relation semantique entre objets. On evoque enfin la gestion d'objets evolutifs

Structured specifications for better verification of heap-manipulating programs

Abstract. Conventional specifications typically have a flat structure that is based primarily on the underlying logic. Such specifications lack structures that could have provided better guidance to the verification process. In this work, we propose to add three new structures to a specification framework for separation logic to achieve a more precise and better guided verification for pointer-based programs. The newly introduced structures empower users with more control over the verification process in the following ways: (i) case analysis can be invoked to take advantage of disjointness conditions in the logic. (ii) early, as opposed to late, instantiation can minimise on the use of existential quantification. (iii) formulae that are staged provide better reuse of the verification process. Initial experiments have shown that structured specifications can lead to more precise verification without incurring any performance overhead.

A Reduction in Time with Electronic Monitoring In Stroke (ARTEMIS): study TA protocol for a randomised multicentre trial

Neuro Imaging Researc

First Observation of Coherent π0\pi^0 Production in Neutrino Nucleus Interactions with Eν<E_{\nu}< 2 GeV

The MiniBooNE experiment at Fermilab has amassed the largest sample to date of $\pi^0$s produced in neutral current (NC) neutrino-nucleus interactions at low energy. This paper reports a measurement of the momentum distribution of $\pi^0$s produced in mineral oil (CH$_2$) and the first observation of coherent $\pi^0$ production below 2 GeV. In the forward direction, the yield of events observed above the expectation for resonant production is attributed primarily to coherent production off carbon, but may also include a small contribution from diffractive production on hydrogen. Integrated over the MiniBooNE neutrino flux, the sum of the NC coherent and diffractive modes is found to be (19.5 $\pm$1.1 (stat) $\pm$2.5 (sys))% of all exclusive NC $\pi^0$ production at MiniBooNE. These measurements are of immediate utility because they quantify an important background to MiniBooNE's search for $\nu_{\mu} \to \nu_e$ oscillations.Comment: Submitted to Phys. Lett.

Global agricultural intensification during climate change: A role for genomics

Summary: Agriculture is now facing the 'perfect storm' of climate change, increasing costs of fertilizer and rising food demands from a larger and wealthier human population. These factors point to a global food deficit unless the efficiency and resilience of crop production is increased. The intensification of agriculture has focused on improving production under optimized conditions, with significant agronomic inputs. Furthermore, the intensive cultivation of a limited number of crops has drastically narrowed the number of plant species humans rely on. A new agricultural paradigm is required, reducing dependence on high inputs and increasing crop diversity, yield stability and environmental resilience. Genomics offers unprecedented opportunities to increase crop yield, quality and stability of production through advanced breeding strategies, enhancing the resilience of major crops to climate variability, and increasing the productivity and range of minor crops to diversify the food supply. Here we review the state of the art of genomic-assisted breeding for the most important staples that feed the world, and how to use and adapt such genomic tools to accelerate development of both major and minor crops with desired traits that enhance adaptation to, or mitigate the effects of climate change. &gt