A circular-arc model (C,A) is a circle C together with a collection A of arcs of C. If A satisfies the Helly Property then (C,A) is a Helly circular-arc model. A (Helly) circular-arc graph is the intersection graph of a (Helly) circular-arc model. Circular-arc graphs and their subclasses have been the object of a great deal of attention, in the literature. Linear time recognition algorithm have...

We discuss the use of K-terminal networks to represent arbitrary clutters. A given clutter has many di¤erent representations, and there does not seem to be any set of simple transformations that can be used to transform one representation of a clutter into any other. We observe that for t 2 the class of clutters that can be represented using no more than t terminals is closed under minors, and ...

A generalized Davenport-Schinzel sequence is one over a finite alphabet that contains no subsequences isomorphic to a fixed forbidden subsequence. One of the fundamental problems in this area is bounding (asymptotically) the maximum length of such sequences. Following Klazar, let Ex(σ, n) be the maximum length of a sequence over an alphabet of size n avoiding subsequences isomorphic to σ. It ha...

Reservoir characterization This paper gives an overview of the activities in geostatistics for the Petroleum industry in the domain of reservoir characterization. This description has been simplified in order to emphasize the original techniques involved. The main steps of a study consist in successively building: • the reservoir architecture where the geometry of the units is established, • th...

This paper characterizes revenue maximizing auctions for a …nite horizon version of the standard IV P model of Myerson (1981) for a seller who cannot commit not to propose a new mechanism, if previously chosen ones fail to allocate the object. We show that a revenue maximizing mechanism in the …rst period assigns the good to the buyer with the highest virtual valuation, provided that it is abov...

In this paper we present a novel approach for brain surfacec characterization based on convexity and concavity analysis of cortical surface mesh. Initially, volumetric Magnetic Resonance Images (MRI) data is processed to generate a discrete representation of cortical surface using low-level segmentation tools and LevelSets method. Afterward, pipeline procedure for brain characterization/labelin...

pure anatase titania (tio2), mixed 1.0 wt.% cerium-anatase titania (1.0 wt.%ceo2-tio2), and mixed 1.0 wt.% zirconia-anatase titania (1.0 wt.%zro2-tio2) nano powders were synthesized by co-precipitation method and characterized using x-ray diffraction (xrd), brunauer-emmett-teller (bet) surface area analysis, uv-vis diffuse reflectance spectroscopy (drs), and transmission electron microscope (te...

background and objectives: biomaterials are widely used in medical devices such as urinary catheters. one of the main problems associated with long term using of the urinary catheters is biofilm formation on their surfaces. many techniques have been presented to reduce the biofilm formation. one of the most revolutionary techniques allowing such surface fictionalization is plasma surface modific...