221 research outputs found
Bivariate modelling of precipitation and temperature using a non-homogeneous hidden Markov model
Aiming to generate realistic synthetic times series of the bivariate process
of daily mean temperature and precipitations, we introduce a non-homogeneous
hidden Markov model. The non-homogeneity lies in periodic transition
probabilities between the hidden states, and time-dependent emission
distributions. This enables the model to account for the non-stationary
behaviour of weather variables. By carefully choosing the emission
distributions, it is also possible to model the dependance structure between
the two variables. The model is applied to several weather stations in Europe
with various climates, and we show that it is able to simulate realistic
bivariate time series
Inferring Peer-Related Emotions in a Collaborative Learning Game
Este artigo apresenta um modelo afetivo para inferir emoções do aluno em um jogo de aprendizagem colaborativa. O modelo é focado na representação e reconhecimento de emoções vinculadas a uma dinâmica de colaboração (tais como orgulho, vergonha, admiração e reprovação). O modelo emprega uma abordagem cognitiva em que as emoções do aluno são representadas e inferidas pela representação da avaliação cognitiva que o aluno faz sobre a “louvabilidade” das interações colaborativas durante o jogo, de acordo com suas expectativas de padrões comportamentais. O modelo afetivo do aluno se apóia em Redes Bayesianas, através das quais são mapeadas dependências causais entre traços da personalidade, objetivos, padrões comportamentais, interações e emoções do aluno. Um jogo colaborativo que suporta mecanismos simples de interação foi implementado como protótipo de teste. Ao fazer uso deste jogo, alunos podem construir soluções compartilhadas de uma classe de problemas lógicos. As variáveis afetivas e cognitivas do modelo e suas relações probabilísticas são detalhadas e a captura de evidências da interação a partir do jogo protótipo é discutida
Species richness and abundance of native leaf miners are affected by the presence of the invasive horse-chestnut leaf miner
The effect of the alien horse-chestnut leaf miner, Cameraria ohridella, on native fauna was studied by comparing the species richness of native leaf miner communities and the abundance of selected native leaf miner species in the presence and absence of horse-chestnut trees infested by C. ohridella, in various environments in Europe. The species richness of native leaf miner communities in Switzerland was lower at sites where C. ohridella was present than at control sites. In Switzerland, France and Bulgaria, several native leaf miner species were significantly less abundant in the vicinity of infested horse-chestnuts. The native species most affected by the presence of the invasive alien species were those occurring early in the year and sharing their parasitoid complex with C. ohridella. These results suggest apparent competition mediated by shared natural enemies because these are the only link between C. ohridella and native leaf miners using other food resource
Opportunistic Composition of Human-Computer Interactions in Ambient Spaces
International audienceWe propose an approach based on Adaptive Multi-Agent Systems, using the principles of Meta-User Interfaces and Opportunism in order to solve Human-Computer Interaction Composition in Ambient interactive spaces. The idea of this approach is to see every component as an agent able to interact with other components to compose autonomously in order to opportunistically suggest to users smart compositions of his interactive ambient environment. We present the notions of component, composition, and human-computer interaction composition. We chose mainly two aspects of the composition of human-computer interaction which are the controllability and finality of the composition. Finally, we illustrate our approach with use cases taken from the neoCampus project
Composition opportuniste de fragments d'IHM pour une interaction adaptative en environnement ambiant
International audienceDans ce papier nous proposons une approche basée sur un système multi-agents adaptatif, en utilisant les principes de Méta-Interactions Homme-Machine et d'Opportunisme dans le but de résoudre le problème de la Composition d'Interactions Homme-Machine dans les espaces interactifs ambiants. L'idée de cette approche est de voir chaque composant comme un agent capable d'interagir avec les autres composants pour composer de manière autonome et ainsi suggérer à l'utilisateur de manière opportuniste des compositions de son environnement ambiant interactif. Nous avons choisi de présenter principalement deux aspects de la composition d'interactions homme-machine, la contrôlabilité et l'objectif de la composition. Enfin nous illustrons notre approche avec des cas d'utilisation dans le cadre d'un projet nommé neoCampus. Mots-clés informatique ubiquitaire ; espaces ambiants interactifs ; interactions homme-machine ; composition opportuniste de composants ; méta-interactions homme-machine ; théorie des systèmes multi-agents adaptatif
Systèmes Agroforestiers A Garcinia Kola Heckel Au Sud-Est Du Bénin : Distribution Géographique, Connaissances Endogènes Et Retombées Financières
This study was carried out in three districts (Avrankou, Adjarra, and Ifangni) of south-eastern Benin, and aimed to analyze the socio-economic and ethnobotanical importance of Garcinia kola Heckel, in order to contribute to their sustainable management. Focus groups were conducted with three groups, composed of 10 owners of G. kola per district each and the result showed that Garcinia kola Heckel became extinct in their naturally occurring state in Benin. Besides, a survey was conducted among 140 owners of G. kola randomly selected in the study area. The results showed that the average number of G. kola feet per owner varies between 3 and 4, and the annual income generated from seeds marketing by an owner is XOF 1036000 in Adjarra district, XOF 356250 in Avrankou district, and XOF 290892 in Ifangni district. Furthermore, the ethnobotanical study showed that G. kola organs are well known and used by local people for medicine, food (for both humans and animals), commercial, spiritual purpose, and for timber and shading. The medicinal use was the most widespread with a diversity of uses (UD = 0.64 in Adjarra, UD = 0.61 in Avrankou and UD = 0.68 in Ifangni). The old men held more knowledge about the use of various organs of the species (ID = 0.91, IE = 0.91), while young women hold less knowledge (ID = 0.20, IE = 0.20). The seeds are the most common part used regardless of the district considered
Floristic and structural changes in secondary forests following agricultural disturbances: the case of Lama forest reserve in Southern Benin
Structural changes in secondary forests are less known in West Africa, and this precludes their management. This study aims at providing quantitative information on floristic composition and structure of the Lama secondary forests (Benin), so as to contribute to their restoration, and fill part of knowledge gaps on West African secondary forests. Data of 77 permanent plots each of 0.5 ha were used to analyze the floristic composition, the trajectory of the recovery and the recovery of stocking in these forests, compared to nearby old-growth forests. The results showed that the forests were less diversified with few species very common in the forest stands; the most dominant were Lonchocarpus sericeus and Anogeissus leiocarpa in the secondary forests, and Dialium guineense, Diospyros mespiliformis and Afzelia africana in the old-growth forests. The secondary forests hold more species than the mature ones. Their compositions will recover that of the original forest because species of the original forest were actively regenerating in the secondary forests. About 28 years after recovery, large trees were insufficient and basal area was about 60% of those of the mature forests. Further studies are needed to elucidate barriers to tree regeneration and dynamics of tree population.© 2016 International Formulae Group. All rights reserved.Keywords: Secondary forest, recovery, diversity, species composition, timber stock, Beni
Erbium Silicide Growth in the Presence of Residual Oxygen
The chemical changes of Ti/Er/n-Si(100) stacks evaporated in high vacuum and
grown ex situ by rapid thermal annealing were scrutinized. The emphasis was
laid on the evolution with the annealing temperature of (i) the Er-Si
solid-state reaction and (ii) the penetration of oxygen into Ti and its
subsequent interaction with Er. For that sake, three categories of specimens
were analyzed: as-deposited, annealed at 300{\deg}C, and annealed at
600{\deg}C. It was found that the presence of residual oxygen into the
annealing atmosphere resulted in a substantial oxidation of the Er film
surface, irrespective of the annealing temperature. However, the part of the Er
film in intimate contact with the Si bulk formed a silicide (amorphous at
300{\deg}C and crystalline at 600{\deg}C) invariably free of oxygen, as
testified by x-ray photoelectron spectroscopy depth profiling and Schottky
barrier height extraction of 0.3 eV at 600{\deg}C. This proves that, even if Er
is highly sensitive to oxygen contamination, the formation of low Schottky
barrier Er silicide contacts on n-Si is quite robust. Finally, the production
of stripped oxygen-free Er silicide was demonstrated after process
optimization
Deletion of endogenous Tau proteins is not detrimental in Drosophila
Human Tau (hTau) is a highly soluble and natively unfolded protein that binds to microtubules within neurons. Its dysfunction and aggregation into insoluble paired helical filaments is involved in the pathogenesis of Alzheimer’s disease (AD), constituting, together with accumulated β-amyloid (Aβ) peptides, a hallmark of the disease. Deciphering both the loss-of-function and toxic gain-of-function of hTau proteins is crucial to further understand the mechanisms leading to neurodegeneration in AD. As the fruit fly Drosophila melanogaster expresses Tau proteins (dTau) that are homologous to hTau, we aimed to better comprehend dTau functions by generating a specific tau knock-out (KO) fly line using homologous recombination. We observed that the specific removal of endogenous dTau proteins did not lead to overt, macroscopic phenotypes in flies. Indeed, survival, climbing ability and neuronal function were unchanged in tau KO flies. In addition, we did not find any overt positive or negative effect of dTau removal on human Aβ-induced toxicity. Altogether, our results indicate that the absence of dTau proteins has no major functional impact on flies, and suggests that our tau KO strain is a relevant model to further investigate the role of dTau proteins in vivo, thereby giving additional insights into hTau functions
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