Agent-oriented techniques for network supervision

This paper presents the results of the Réseau futé (smart net) project, the goal of which is to use distributed AI and multi-agent techniques for network management and supervision. More precisely, these techniques have been applied to the partial automation of the dynamic processing (what is known about a network is always incomplete and can change at any time) of alarms and of various event notifications received by network management platforms. The system that we propose is able for example to automatically handle some alarms or to filter events of no-interest for a given operator. To achieve this goal, an assistant, or interface agent according to the model proposed by Patti Maes [MK93], has been realized. The goal of the assistant is first to learn, by observation, the behavior of the network supervision operator and second to reproduce such a behavior when the conditions in which the behavior has been learned are detected again. The learned information are stored using chronicles [Gha94]. A chronicle is a data-structure allowing programmers to represent sequences of events while taking temporal knowledge into account. Our assistant has been implemented and tested within Magenta which is a program, written in Smalltalk, that simulates (in a simplified way) a network management platform. This program respects roughly the gdmo and cmis standards.     

A semantics of introspection in a reflective prototype-based language

In Malenfant et al. [19], we have described a reflective model for a prototype-based language based on thelookup o apply reflective introspection protocol. In this paper, we augment our previous protocol by converting it to handle continuations reified as first-class objects. First-class continuations provide much more control over the current computation; during the introspection phase fired by message sending, they make it possible not only to change the behavior of the program for that message but also for the entire future computation. In this paper, we provide this introspection protocol with a formal semantics. This result is obtained by exhibiting a mapping from program configurations to priority rewrite systems (PRS) as well as a mapping from message expressions to ground first-order terms used to query the PRS. Other advantages of this approach are: to ensure the termination of the introspection using the smallest set of formally justified conditions and to provide a clear declarative account of this reflective protocol. The PRS also appears as a meta-level to the base language, independent of the implementation, but from which we derive fundamental clues to obtain an efficient language processor. By our new model, we finally highlight the link between reflection in object-oriented languages and the one originally proposed by 3-Lisp [24], although object-orientation provides reusability to reflection, making it easier to use.     

Properties of bituminous mixtures at low temperatures and relations with binder characteristics

Within the framework of a partnership between the “Département Génie Civil et Batiment” of the ENTPE, Eurovia and Appia, a research work including a large experimental campaign on the thermomechanical behavior of bituminous materials at low temperatures is proposed. The aim is to establish the links between the characteristics of the binder and the properties of bituminous mixes at low temperatures. Four different bitumens have been used with one type of aggregate and grading. The low temperature behavior of binders was evaluated with three fundamental tests: the complex modulus determination, the Bending Beam Rheometer and the tensile strength at a constant strain rate and constant temperatures. The thermomechanical behavior of bituminous mixes has been studied by performing complex modulus tests, measurements of the coefficient of thermal dilatation and contraction, tensile tests at constant temperatures and strain rates, and Thermal Stress Restrained Specimen Tests. The results are analyzed considering a rational approach. Some pertinent links between binders and mixes properties are established. Characteristics which are pertinent and discriminating enough with regard to the thermal cracking of bituminous mixes at low temperatures are presented.

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Résumé Dans le cadre d'un partenariat entre le “Département Génie Civil et Batiment” de l'école Nationale des TPE, Eurovia (groupe VINCI) et Appia (groupe EIFFAGE), une vaste campagne de recherche sur le comportement thermo-mécanique des matériaux bitumineux a été menée. Le but de cette étude est d'établir les liens existants entre les caractéristiques du liant et les propriétés de l'enrobé à basses températures. Quatre bitumes différents et une seule formulation d'enrobé ont ici été étudiés. Le comportement à basse température des bitumes a été évalué avec trois tests fondamentaux: i) l'essai de module complexe, ii) l'essai de fluage au rhéomètre BBR, iii) l'essai de traction directe SHRP à vitesse de déformation constante et températures constantes. le comportement thermo-mécanique des enrobés bitumineux a été étudié en réalisant i) des essais de module complexe, ii) des mesures du coefficient de dilatation-contraction thermique, iii) des essais de traction à vitesses de déformation constantes, ainsi que iv) des essais de retrait thermique empêché (TSRST). A partir des résultats obtenus, des liens pertiments entre les propriétés des liants et des enrobés, et des caractéristiques suffisamment discriminantes au regard des propriétés à basse température des enrobés sont mis en évidence.

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Editorial Note Presented at the 6^th International RILEM Symposium on Performance Testing and Evaluation of Bituminous Materials (PTEBM'03), held on 14^th–16^th April 2003, in Zurich, Switzerland, this paper was selected as an outstanding communication and peer-reviewed by the Scientific Committee of the JournalMaterials and Structures. Mr. Hervé Di Benedetto participates in RILEM TCs 182-PEB ‘Performance testing and evaluation of bituminous materials’, ATB ‘Advanced testing and characterization of bituminous materials’ and CAP ‘Cracking in Asphalt Pavements’.     

Probabilistic parametric approach for rutting evaluation: application to hot and warm asphalt

This paper deals with a stochastic approach to evaluate the rut depth of hot and warm bituminous mixtures. First, the rutting performance of both mixtures using the French rutting tester device was evaluated. Given the random uncertainties derived from the numerous experimental measurements of the rut depth, statistical information was collected. Accordingly, the entropy maximum principle was used here to define adequate probability density function of the rut. Confidence regions with a high probability of 99% were determined for the estimation of the rut depth. In addition, comparison of mechanical and rheological results is performed with aged bitumen recovered from reclaimed asphalt and virgin bitumen to analyse the effect of ageing on bitumen viscoelastic properties. The experimental characterisation of the different binders based on rheological and conventional tests showed stiffening and hardening effects due to bitumen ageing.     

Ultraviolet radiation aging impact on physicochemical properties of crosslinked polyethylene cable insulation

This article deals within the study of the effect of artificial radiations on physical and chemical properties of the crosslinked polyethylene (XLPE) material, widely used for manufacturing high-voltage cables. Within this framework, several experimental tests, using essential characterization techniques, were performed to study XLPE behavior under ultraviolet (UV) aging. Attenuated total reflection Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, X-ray diffraction, and scanning electron microscopy were thus carried out to identify the main structure changes of the material before and after exposure to UV. In addition, appearance changes and DC (Direct Current) volume resistivity were evaluated. The obtained results showed that UV radiation has a great effect on the physicochemical properties of XLPE cable insulation. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48575.     

ReTiNbO6系微波介质陶瓷的研究现状及展望

综述了ReNbTiO6系微波介质陶瓷的发展过程和研究现状,并且介绍了在研究中存在的问题及未来发展趋势.     

Optimally adaptive transform coding

The optimal linear block transform for coding images is well known to be the Karhunen-Loeve transformation (KLT). However, the assumption of stationarity in the optimality condition is far from valid for images. Images are composed of regions whose local statistics may vary widely across an image. While the use of adaptation can result in improved performance, there has been little investigation into the optimality of the criterion upon which the adaptation is based. In this paper we propose a new transform coding method in which the adaptation is optimal. The system is modular, consisting of a number of modules corresponding to different classes of the input data. Each module consists of a linear transformation, whose bases are calculated during an initial training period. The appropriate class for a given input vector is determined by the subspace classifier. The performance of the resulting adaptive system is shown to be superior to that of the optimal nonadaptive linear transformation. This method can also be used as a segmentor. The segmentation it performs is independent of variations in illumination. In addition, the resulting class representations are analogous to the arrangement of the directionally sensitive columns in the visual cortex.     

The contribution of CT to perinatal intracranial hemorrhage including that accompanying apparently uncomplicated delivery at full term

The clinical and CT evolution of intracranial bleeding in six neonates (four full-term and two premature) has been followed. Clinical symptoms, risk factors, evolution, sequellae and prognostic factors of intracranial hemorrhage in the newborn are reviewed. The routine use of CT for detection and survey of perinatal hemorrhage and its sequellae is recommended.     

Image Compression Using KLT, Wavelets and an Adaptive Mixture of Principal Components Model

In this paper, we present preliminary results comparing the nature of the errors introduced by the mixture of principal components (MPC) model with a wavelet transform and the Karhunen Loève transform (KLT) for the lossy compression of brain magnetic resonance (MR) images. MPC, wavelets and KLT were applied to image blocks in a block transform coding scheme. The MPC model partitions the space of image blocks into a set of disjoint classes and computes a separate KLT for each class. In our experiments, though both the wavelet transform and KLT obtained a higher peak signal to noise ratio (PSNR) than MPC, according to radiologists, MPC preserved the texture and boundaries of gray and white matter better than the wavelet transform or KLT.