350 research outputs found

    The Hanabi Challenge: A New Frontier for AI Research

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    From the early days of computing, games have been important testbeds for studying how well machines can do sophisticated decision making. In recent years, machine learning has made dramatic advances with artificial agents reaching superhuman performance in challenge domains like Go, Atari, and some variants of poker. As with their predecessors of chess, checkers, and backgammon, these game domains have driven research by providing sophisticated yet well-defined challenges for artificial intelligence practitioners. We continue this tradition by proposing the game of Hanabi as a new challenge domain with novel problems that arise from its combination of purely cooperative gameplay with two to five players and imperfect information. In particular, we argue that Hanabi elevates reasoning about the beliefs and intentions of other agents to the foreground. We believe developing novel techniques for such theory of mind reasoning will not only be crucial for success in Hanabi, but also in broader collaborative efforts, especially those with human partners. To facilitate future research, we introduce the open-source Hanabi Learning Environment, propose an experimental framework for the research community to evaluate algorithmic advances, and assess the performance of current state-of-the-art techniques.Comment: 32 pages, 5 figures, In Press (Artificial Intelligence

    Complete genome sequence of streptococcus pneumoniae virulent phage MS1

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    The lytic Streptococcus pneumoniae phage MS1 was isolated from a throat swab of a patient with symptoms of upper respiratory tract infection. The genome of this siphophage has 56,075 bp, 42.3% GC content, and 77 open reading frames, including queuosine biosynthesis genes. Phage MS1 is related to pneumococcal phage Dp-1

    Preferential homologous chromosome pairing in a tetraploid intergeneric somatic hybrid (Citrus reticulata + Poncirus trifoliata)revealed by molecular marker inheritance

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    The creation of intergeneric somatic hybrids between Citrus and Poncirus is an efficient approach for citrus rootstock breeding, offering the possibility of combining beneficial traits from both genera into novel rootstock lineages. These somatic hybrids are also used as parents for further tetraploid sexual breeding. In order to optimize these latter breeding schemes, it is essential to develop knowledge on the mode of inheritance in the intergeneric tetraploid hybrids. We assessed the meiotic behavior of an intergeneric tetraploid somatic hybrid resulting from symmetric protoplast fusion of diploid Citrus reticulata and diploid Poncirus trifoliata. The analysis was based on the segregation patterns of 16 SSR markers and 9 newly developed centromeric/pericentromeric SNP markers, representing all nine linkage groups of the Citrus genetic map. We found strong but incomplete preferential pairing between homologues of the same ancestral genome. The proportion of gametes that can be explained by random meiotic chromosome associations (τ) varied significantly between chromosomes, from 0.09 ± 0.02 to 0.47 ± 0.09, respectively, in chromosome 2 and 1. This intermediate inheritance between strict disomy and tetrasomy, with global preferential disomic tendency, resulted in a high level of intergeneric heterozygosity of the diploid gametes. Although limited, intergeneric recombinations occurred, whose observed rates, ranging from 0.09 to 0.29, respectively, in chromosome 2 and 1, were significantly correlated with τ. Such inheritance is of particular interest for rootstock breeding because a large part of the multi-trait value selected at the teraploid parent level is transmitted to the progeny, while the potential for some intergeneric recombination offers opportunities for generating plants with novel allelic combinations that can be targeted by selection

    Surveillance des centres d'usinage grande vitesse par approche cyclostationnaire et vitesse instantanée

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    Dans l industrie de fabrication mécanique et notamment pour l utilisation des centres d usinage haute vitesse, la connaissance des propriétés dynamiques du système broche-outil-pièce en opération est d une grande importance. L accroissement des performances des machines-outils et des outils de coupe a œuvré au développement de ce procédé compétitif. D innombrables travaux ont été menés pour accroître les performances et les remarquables avancées dans les matériaux, les revêtements des outils coupants et les lubrifiants ont permis d accroître considérablement les vitesses de coupe tout en améliorant la qualité de la surface usinée. Cependant, l utilisation rationnelle de cette technologie est encore fortement pénalisée par les lacunes dans la connaissance de la coupe, que ce soit au niveau microscopique des interactions fines entre l outil et la matière coupée, aussi bien qu au niveau macroscopique intégrant le comportement de la cellule élémentaire d usinage, si bien que le comportement dynamique en coupe garde encore une grande part de questionnement et exige de l utilisateur un bon niveau de savoir-faire et parfois d empirisme pour exploiter au mieux les capacités des moyens de production. Le fonctionnement des machines d usinage engendre des vibrations qui sont souvent la cause des dysfonctionnements et accélère l usure des composantes mécaniques (roulements) et outils. Ces vibrations sont une image des efforts internes des systèmes, d où l intérêt d analyser les grandeurs mécaniques vibratoires telle que la vitesse ou l accélération vibratoire. Ces outils sont indispensables pour une maintenance moderne dont l objectif est de réduire les coûts liés aux pannesIn machining field, chatter phenomenon takes a lot of interest because manufacturing enterprises are turning to the automation system and the development of reliable and robust monitoring system to provide increased productivity, improved part quality and reduced costs. Chatter occurrence has several negatives effects: a) Poor surface quality, b) Unacceptable inaccuracy, c) Excessive noise, d) Machine tool damage, e) Reduced material removal rate, f) Increase costs in terms of production time, g) Waste of material, h) Environmental impact in terms of materials and energy. Moreover, chatter monitoring is not an easy task for various reasons. Firstly, the non linearity of machining processes and the time-varying of systems complicate this task. Secondly, the sensitivity and the dependency of acquired signals from sensors on different factors, such as machining condition, cutting tool geometry and workpiece material. Thirdly, at high rotating speeds, the gyroscopic effects on the spindle dynamics in addition to the centrifugal force on the bearings and thermal effects become more relevant thus affecting the stability of the system. For these reasons, demands for an advanced automatic chatter detection and monitoring system for optimizing and controlling machining processes becomes a topic of enormous interest. Several researches in this field are performed. Advanced monitoring and detection methods are developed mostly relying on time, frequency and time-frequency analysis. In order to detect chatter in milling centers, three new methods are studied and developed using advanced techniques of signal processing and exploiting cyclostationarity property of signals acquiredST ETIENNE-Bib. électronique (422189901) / SudocSudocFranceF

    Performance on an Everyday Life Activity in Persons Diagnosed with Alcohol Dependency Compared to Healthy Controls: Relations between a Computerized Shopping Task and Cognitive and Clinical Variables†

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    Aim: Persons diagnosed with alcohol dependency often suffer from cognitive impairments. Little is known, however, concerning how these cognitive deficits impact complex, everyday life activities. We set out to better characterize the nature of everyday life difficulties in patients with alcohol dependency using a computerized shopping task. Methods: A computerized real-life activity task (shopping task) required participants to shop for a list of eight grocery store items. Twenty individuals diagnosed with alcohol dependency and 20 healthy controls were administered a battery of cognitive tests, clinical scales and the shopping task. Results: Performance on the shopping task significantly differentiated patients and healthy controls for several variables and, in particular, for total time. Total time to complete the task correlated significantly with poor performance on measures of processing speed, verbal episodic memory, cognitive flexibility and inhibition. Total time was significantly correlated with poorer everyday life functioning and longer duration of illness. Conclusion: This computerized task is a good proxy measure of the level of everyday life and cognitive functioning of persons diagnosed with alcohol dependenc

    Security Evaluation and Hardening of Free and Open Source Software (FOSS)

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    Recently, Free and Open Source Software (FOSS) has emerged as an alternative to Commercial-Off- The-Shelf (COTS) software. Now, FOSS is perceived as a viable long-term solution that deserves careful consideration because of its potential for significant cost savings, improved reliability, and numerous advantages over proprietary software. However, the secure integration of FOSS in IT infrastructures is very challenging and demanding. Methodologies and technical policies must be adapted to reliably compose large FOSS-based software systems. A DRDC Valcartier-Concordia University feasibility study completed in March 2004 concluded that the most promising approach for securing FOSS is to combine advanced design patterns and Aspect-Oriented Programming (AOP). Following the recommendations of this study a three years project have been conducted as a collaboration between Concordia University, DRDC Valcartier, and Bell Canada. This paper aims at presenting the main contributions of this project. It consists of a practical framework with the underlying solid semantic foundations for the security evaluation and hardening of FOSS
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