On the Super-Additivity and Estimation Biases of Quantile Contributions

Sample measures of top centile contributions to the total (concentration) are downward biased, unstable estimators, extremely sensitive to sample size and concave in accounting for large deviations. It makes them particularly unfit in domains with power law tails, especially for low values of the exponent. These estimators can vary over time and increase with the population size, as shown in this article, thus providing the illusion of structural changes in concentration. They are also inconsistent under aggregation and mixing distributions, as the weighted average of concentration measures for A and B will tend to be lower than that from A U B. In addition, it can be shown that under such fat tails, increases in the total sum need to be accompanied by increased sample size of the concentration measurement. We examine the estimation superadditivity and bias under homogeneous and mixed distributions

Policy-based autonomic control service

Recently, there has been a considerable interest in policy-based, goal-oriented service management and autonomic computing. Much work is still required to investigate designs and policy models and associate meta-reasoning systems for policy-based autonomic systems. In this paper we outline a proposed autonomic middleware control service used to orchestrate selfhealing of distributed applications. Policies are used to adjust the systems autonomy and define self-healing strategies to stabilize/correct a given system in the event of failures

A deliberative model for self-adaptation middleware using architectural dependency

A crucial prerequisite to externalized adaptation is an understanding of how components are interconnected, or more particularly how and why they depend on one another. Such dependencies can be used to provide an architectural model, which provides a reference point for externalized adaptation. In this paper, it is described how dependencies are used as a basis to systems' self-understanding and subsequent architectural reconfigurations. The approach is based on the combination of: instrumentation services, a dependency meta-model and a system controller. In particular, the latter uses self-healing repair rules (or conflict resolution strategies), based on extensible beliefs, desires and intention (EBDI) model, to reflect reconfiguration changes back to a target application under examination

Essai de conceptualisation de l’attractivite des espaces ruraux Algeriens

L’article est une réflexion sur les espaces ruraux algériens et leur devenir. La progression rapide de  l’urbanisation, l’exode rural qui en découle et l’accentuation de la dépendance alimentaire posent la question du devenir des espaces ruraux dans un contexte d’ouverture économique et d’une volonté d’encourager la  métropolisation exprimée dans le schéma national d’aménagement du territoire (SNAT). Cette réflexion est un prolongement d’un travail de terrain effectué dans le cadre de la thèse de doctorat. A partir d’une enquête  auprès d’industriels ayant choisi de localiser leur entreprise dans des zones rurales pour connaître leurs motivations, nous nous interrogeons sur les facteurs d’attractivité des espaces ruraux algériens.MOTS CLEFS: Espaces ruraux, espaces urbains, attractivité, compétitivité, aménagement du territoir

REFWA: An Efficient and Fair Congestion Control Scheme for LEO Satellite Networks

科研費報告書収録論文(課題番号:17500030/研究代表者:加藤寧/インターネットと高親和性を有する次世代低軌道衛星ネットワークに関する基盤研究

The Future Has Thicker Tails than the Past: Model Error As Branching Counterfactuals

Abstract Ex ante forecast outcomes should be interpreted as counterfactuals (potential histories), with errors as the spread between outcomes. We reapply measurements of uncertainty about the estimation errors of the estimation errors of an estimation treated as branching counterfactuals. Such recursions of epistemic uncertainty have markedly different distributial properties from conventional sampling error, and lead to fatter tails in the projections than in past realizations. Counterfactuals of error rates always lead to fat tails, regardless of the probability distribution used. A mere .01% branching error rate about the STD (itself an error rate), and .01% branching error rate about that error rate, etc. (recursing all the way) results in explosive (and infinite) moments higher than 1. Missing any degree of regress leads to the underestimation of small probabilities and concave payoffs (a standard example of which is Fukushima). The paper states the conditions under which higher order rates of uncertainty (expressed in spreads of counterfactuals) alters the shapes the of final distribution and shows which a priori beliefs about conterfactuals are needed to accept the reliability of conventional probabilistic methods (thin tails or mildly fat tails)

A Dynamic Service Level Negotiation Mechanism for QoS Provisioning in NGEO Satellite Networks

科研費報告書収録論文(課題番号:17500030/研究代表者:加藤寧/インターネットと高親和性を有する次世代低軌道衛星ネットワークに関する基盤研究