10,307 research outputs found
Scalability and Robustness of a Network Resource Allocation System Using Market-Based Agents
No full textIn this paper, we consider issues associated with scalability and robustness in designing a market-based multi-agent system that allocates bandwidth in a communications network. Specifically, an empirical evaluation is carried out to assess the system performance under a variety of design configurations in order to provide an insight into network deployment issues. This extends our previous work in which we developed an application that makes use of market-based software agents that compete in decentralised marketplaces to buy and sell bandwidth resources in a network that is partitioned into regions, each with a separate market server. We investigate the average call success rate and average message load per market server, as the number of markets are scaled up in a fixed size network. The same investigations are performed in the presence of single market failures. Finally, for both the failure and non-failure cases, a trade-off is found between their average call success rates and message load per server in order to find an optimum number of regions to deploy in the network
N° 28 — René MOREAU
No full textMoreau René, Bernard Danièle, Lepagnot-Leca Françoise. N° 28 — René MOREAU. In: Témoins et acteurs des politiques de l'éducation depuis la Libération. Tome 3 - Inventaire de quarante entretiens. Paris : Institut national de recherche pédagogique, 2002. pp. 84-87. (Témoins et acteurs des politiques de l'éducation, 1
N° 46 — MOREAU Yannick
No full textMoreau Yannick, Stern Marie, Mignaval Pierre. N° 46 — MOREAU Yannick. In: Témoins et acteurs des politiques de l'éducation depuis la Libération. Tome 4 - Inventaire de soixante-quatre entretiens. Paris : Institut national de recherche pédagogique, 2005. pp. 130-131. (Témoins et acteurs des politiques de l'éducation, 1
The Fables: Gustave Moreau
No full textOccasional mention of Gustave Moreau and sample offerings of specific work of his did not prepare me for this revelation of the extent of his work on fables. Moreau created some 64 watercolor illustrations of La Fontaine's fables, first exhibited in 1886 and last exhibited in 1906. This present book is the catalogue of a recent exhibit at the Rothschilds' Waddesdon Manor. The book's author, Juliet Carey, was curator of that exhibit. The book, large format (9¾" x 12") and 168 pages long, gives accounts of Moreau's life, including the fable watercolors; of La Fontaine and the fables; and of animal studies by Moreau that prepared for this work. The bulk of the book is then an impressive catalogue featuring a large colored illustration of each of the 35 fables in the exhibit, starting with "Allegory of Fable," in which fable rides on a chimaera. Among the best, for me, are WS; "The Monkey and the Dolphin"; "Death and the Woodcutter," in which death is a seductive woman; and FK. The book's last pictorial section is a brief account of Felix Bracquemond's black and white etchings based on Moreau's fables. Of the many critical comments included here, the most helpful for me is that Moreau "explored states of consciousness." Moreau achieved early fame with popular works exploring mythology, e.g., "Oedipus and the Sphinx." This book is a new treasure in the collection!Juliet Care
Scalability and robustness of a market-based network resource allocation system
No full textIn this paper, we consider issues related to scalability and robustness in designing a market-based multi-agent system that allocates bandwidth in a communications network. Specifically, an empirical evaluation is carried out to assess the system performance under a variety of design configurations in order to provide an insight into network deployment issues. This extends our previous work in which we developed an application that makes use of market-based software agents that compete in decentralised marketplaces to buy and sell bandwidth resources. Our new results show that given a light to moderate network traffic load, partitioning the network into a few regions, each with a separate market server, gives a higher call success rate than by using a single market. Moreover, a trade-off in the number of regions was also noted between the average call success rate and the number of messages received per market server. Finally, given the possibility of market failures, we observe that the average call success rates increase with an increasing number of markets until a maximum is reached
Implementation and Evaluation of a Protocol for Recording Process Documentation in the Presence of Failures
No full textThe provenance of a particular data item is the process that led to that piece of data. Previous work has enabled the creation of detailed representation of past executions for determining provenance, termed process documentation. However, current solutions to recording process documentation assume a failure free environment. Failures result in process documentation not being recorded, thereby causing the loss of evidence that a process occurred. We have designed F-PReP, a protocol to guarantee the recording of process documentation in the presence of failures. This paper discusses its implementation and evaluates its performance. The result reveals that it introduces acceptable overhead
The Foundations for Provenance on the Web
No full textProvenance, i.e., the origin or source of something, is becoming an important concern, since it offers the means to verify data products, to infer their quality, to analyse the processes that led to them, and to decide whether they can be trusted. For instance, provenance enables the reproducibility of scientific results; provenance is necessary to track attribution and credit in curated databases; and, it is essential for reasoners to make trust judgements about the information they use over the Semantic Web. As the Web allows information sharing, discovery, aggregation, filtering and flow in an unprecedented manner, it also becomes very difficult to identify, reliably, the original source that produced an information item on the Web. Since the emerging use of provenance in niche applications is undoubtedly demonstrating the benefits of provenance, we contend that provenance can and should reliably be tracked and exploited on the Web, and we survey the necessary foundations to achieve such a vision. Using multiple data sources, we have compiled the largest bibliographical database on provenance so far. This large corpus allows us to analyse emerging trends in the research community. Specifically, using the CiteSpace tool, we identify clusters of papers that constitute research fronts, from which we derive characteristics that we use to structure our foundational framework for provenance on the Web. We note that such an endeavour requires a multi-disciplinary approach, since it requires contributions from many computer science sub-disciplines, but also other non-technical fields given the human challenge that is anticipated. To develop our vision, it is necessary to provide a definition of provenance that applies to the Web context. Our conceptual definition of provenance is expressed in terms of processes, and is shown to generalise various definitions of provenance commonly encountered. Furthermore, by bringing realistic distributed systems assumptions, we refine our definition as a query over assertions made by processes. Given that the majority of work on provenance has been undertaken by the database, workflow and e-science communities, we review some of their work, contrasting approaches, and focusing on important topics we believe to be crucial for bringing provenance to the Web, such as abstraction, collections, storage, queries, workflow evolution, semantics and activities involving human interactions. However, provenance approaches developed in the context of databases and workflows essentially deal with closed systems. By that, we mean that workflow or database management systems are in full control of the data they manage, and track their provenance within their own scope, but not beyond. In the context of the Web, a broader approach is required by which chunks of provenance representation can be brought together to describe the provenance of information flowing across multiple systems. This is the specific purpose of the Open Provenance Vision, which is an approach that consists of controlled vocabulary, serialization formats and interfaces that allow the provenance of individual systems to be expressed, connected in a coherent fashion, and queried seamlessly. In this context, the Open Provenance Model is an emerging community-driven representation of provenance, which has been actively used by some twenty teams to exchange provenance information according to the Open Provenance Vision. Having identified an open approach and a model for provenance, we then look at techniques that have been proposed to expose provenance over the Web. We also study how Semantic Web technologies have been successfully exploited to express, query and reason over provenance. Symmetrically, we also identify how Semantic Web technologies such as RDF underpinning the Linked Data effort bring their own difficulties with respect to provenance. A powerful argument for provenance is that it can help make systems transparent, so that it becomes possible to determine whether a particular use of information is appropriate under a set of rules. Such capability helps make systems and information accountable. To offer accountability, provenance itself must be authentic, and rely on security approaches that we review. We then discuss systems where provenance is the basis of an auditing mechanism to check past processes against rules or regulations. In practice, not all users want to check and audit provenance, instead, they may rely on measures of quality or trust; hence, we review emerging provenance-based approaches to compute trust and quality of data
La grève des cheminots en 1968. Entretien avec Daniel Moreau
No full textDreyfus-Armand Geneviève, Moreau Daniel. La grève des cheminots en 1968. Entretien avec Daniel Moreau. In: Matériaux pour l'histoire de notre temps, n°11-13, 1988. Mai-68 : Les mouvements étudiants en France et dans le monde, sous la direction de Stéphane Courtois. pp. 214-221
Learning users' interests by quality classification in market-based recommender systems
No full textRecommender systems are widely used to cope with the problem of information overload and, to date, many recommendation methods have been developed. However, no one technique is best for all users in all situations. To combat this, we have previously developed a market-based recommender system that allows multiple agents (each representing a different recommendation method or system) to compete with one another to present their best recommendations to the user. In our system, the marketplace encourages good recommendations by rewarding the corresponding agents who supplied them according to the users’ ratings of their suggestions. Moreover, we have theoretically shown how our system incentivises the agents to bid in a manner that ensures only the best recommendations are presented. To do this effectively in practice, however, each agent needs to be able to classify its recommendations into different internal quality levels, learn the users’ interests for these different levels, and then adapt its bidding behaviour for the various levels accordingly. To this end, in this paper we develop a reinforcement learning and Boltzmann exploration strategy that the recommending agents can exploit for these tasks. We then demonstrate that this strategy does indeed help the agents to effectively obtain information about the users’ interests which, in turn, speeds up the market convergence and enables the system to rapidly highlight the best recommendations
- …
