Assisted Tandem Palladium(II)/Palladium(0)‐Catalyzed C‐ and N‐Arylations of Quinoxalin‐2(1 H)‐ones in Water

A straightforward assisted tandem palladium(II)‐ and palladium(0)‐catalyzed direct C‐3 and N‐4 arylation of quinoxalin‐2(1 H)‐ones with boronic acids and aryl halides in water as safe and cheap solvent is reported. This environmentally friendly catalytic protocol is compatible with a wide range of functional groups and allows construction of various biologically important quinoxalin‐2(1 H)‐one backbones.

     

Modelling approaches for the estimation of irreducible water saturation and heterogeneities of the commercial Ashtart reservoir from the Gulf of Gabès, Tunisia

Oil production based on reserves in place in the Ashtart oilfield required the precise knowledge of the main reservoir parameters including porosity, permeability and irreducible water saturation. The reservoir series is comprised of Nummulitid but heterogeneous limestones of the El Garia Formation, the petrofacies texture, geometry and petrophysical parameters of which were apprehended using seismic profiles; gamma-ray and sonic lateral logs, as well as cores and cuttings taken in drillwells. The evaluation of residual oil saturation, multiphase flow and oil production techniques from the Ashtart reservoir also depend on variations and zoning of the irreducible water saturation. Estimation of the initial water saturation and hence variations in the capillary pressure in the reservoir, required compilations of porosity data measured on cores, supplemented by additional but computed porosities based on acoustic log diagrams. Furthermore, Gamma Ray, Sonic log, and well to well correlations tied to core results and well cuttings, help recognize the layered lithologies within the El Garia flat lying but stratified, Ypresian in origin reservoir rocks. Abundant permeability and porosity values compiled in the light of seismic sequence and Gamma Ray and Sonic log details, were integrated in an empirical approach using the Leverett J function, to model the irreducible water saturation depending on the capillary pressure distribution in the whole reservoir. Variations of this principal hydraulic parameter in a wide range (S_wir: 12 to 40%) compared to the preceding lithostratigraphic, petrographical and petrophysical results help recognize four main rock pore types in the commercial Ashtart reservoir. These vary from (1) a zone with a rock pore type showing an irreducible water saturation as low as 12%, and a fairly good reservoir character in the lower third part of the lithologic column which is thought to channelize a multiphase fluid flow in the global oilfield, (2) to those zones built-up of rock pore types with higher initial water saturation amounts which in certain cases tend to indicate zones of degraded reservoir. Our study suggests that diagenesis prevalently controls porosity, due to operative dissolutions of the Nummulitid tests/bioclasts, and cementation; moreover, diagenesis exerts effects on permeability by interconnecting intergranular and intratest pore spaces. In contrast, microfracturing enhances permeability of the reservoir. This is notably the case in the fairly permeable central zone in the Ashtart reservoir with excellent petrophysical parameters, but which were found to degrade gradually towards its peripheries.     

On-line resources allocation for ATM networks with rerouting

This paper presents an application we developed for France Telecom R&D to solve a difficult real-life network problem. The problem takes place in an Asynchronous Transfer Mode (ATM) network administration context and consists in planning demands of connection over a period of 1 year. A new demand is accepted if both bandwidth and Quality of Service (QoS) requirements are satisfied. Demands are not known prior to the assignment and must be performed on-line according to their arrival. Moreover, the acceptance or the reject of a demand must be decided within a given time of 1 min.     

A multi-level conceptual data reduction approach based on the Lukasiewicz implication

Starting from fuzzy binary data represented as tables in the fuzzy relational database, in this paper, we use fuzzy formal concept analysis to reduce the tables size to only keep the minimal rows in each table, without losing knowledge (i.e., association rules extracted from reduced databases are identical at given precision level). More specifically, we develop a fuzzy extension of a previously proposed algorithm for crisp data reduction without loss of knowledge. The fuzzy Galois connection based on the Lukasiewicz implication is mainly used in the definition of the closure operator according to a precision level, which makes data reduction sensitive to the variation of this precision level.     

Some experiments with the interpretation strategy of a modular computer vision system

This paper is concerned with the general problem of computer vision. That is, given a colored input picture, design a system which segments the objects in the scene and interprets them appropriately. During the past few years, we have been engaged in the development of a modular, data-driven computer vision system to achieve this goal. The details have appeared elsewhere, so here we have primarily emphasized the mechanism for updating the hypothesized region interpretations. This is achieved by means of a relaxation labeling process which has continuous access to a scene model describing the picture under consideration.     

Bayesian prediction for business mortality analysis

Summary This paper is concerned with business mortality analysis in a Bayesian setting. We assume that a businessman startsN businesses at different points of time and at a certain epoch referred to as the ‘present’, the failure times of the failed businesses and the survival times of the still surviving businesses are recorded. Bayesian prediction for business mortality or survival up to a future time pointt ₀ is made under the assumptions of a Weibull business survival distribution (WBSD) and the squared error loss function (SELF). The results are extended to the situation where one of the observed times of business failure may possibly be an outlier.