Application of Computational Mechanics to the Analysis of Seismic Time-series via Numerical Optimisation

We apply the Computational Mechanics approach to the analysis of time-series representative of geophysical measurements. The algorithm employed is the Causal-State Splitting Reconstruction (CSSR) algorithm. We address a number of data pre-processing steps which are necessary when analysing complex time-series and specific to symbolised time-series analysis tools such as CSSR. We cast the choice of input parameters for the CSSR algorithm and time-series symbolisation, into an optimisation problem, with the aim of maximising the predictability of events of specific interest. Our approach is problem independent and can be easily extended to other applications. This research highlights the challenges to be overcome when analysing complex time-series using the Computational Mechanics approach. We also discuss further developments necessary to extend the approach to real data applications.

Slippage of binary fluid mixtures in a nanopore

This work focuses on the slip phenomenon at the fluid–solid interface accompanying Poiseuille flow of simple binary miscible fluids in a slit nanopore. To explore such flows, molecular dynamics simulations are used on Lennard–Jones binary mixtures composed of species of varying affinities with the walls. The results have shown that the apparent slip magnitude at the fluid–solid interface depends largely on the species that is dominant in contact with the walls. In addition, it has been shown that the velocity profiles of each species (of different “wettability”) does not superpose with the velocity profile of the mixture and such a result points out the limitations of the classical approaches based on a single momentum conservation equation to deal with mixtures flow in nanochannels.     

IpMorph: fingerprinting spoofing unification

There is nowadays a wide range of TCP/IP stack identification tools that allow to easily recognize the operating system of foreseen targets. The object of this article is to show that fingerprint concealment and spoofing are uniformly possible against different known fingerprinting tools. We present IpMorph, counter-recognition software implemented as a user-mode TCP/IP stack, ensuring session monitoring and on the fly packets re-writing. We detail its operation and use against tools like Nmap, Xprobe2, Ring2, SinFP and p0f, and we evaluate its efficiency thanks to a first technical implementation that already covers most of our objectives.     

Malicious origami in PDF

People have now come to understand the risks associated with MS Office documents: whether those risks are caused by macros or associated breaches. PDF documents on the contrary seem to be much more secure and reliable. This false sense of security mainly comes from the fact that these documents appear to be static. The widespread use of Acrobat Reader is most likely also accountable for this phenomenon to the detriment of software that modifies PDFs. As a consequence, PDF documents are perceived as images rather than active documents. And as everyone knows, images are not dangerous, so PDFs aren’t either. In this article we present the PDF language and its security model, and then the market leader of PDF software, Acrobat Reader. Finally, we will show how this format can be used for malicious purposes.     

Molybdocobaltate cobalt salts: New starting materials for hydrotreating catalysts

This paper deals with the use of Anderson heteropolyanions as alternative starting materials to the ammonium heptamolybdate and cobalt nitrate for the preparation of hydrotreatment oxidic precursors. Ammonium and cobalt salts of molybdocobaltate anions were synthesized and impregnated on alumina. The evolution of these compounds along the different steps of preparation of the oxidic precursors has been followed using various physical techniques such as Raman, XAS and UV–vis spectroscopies. It has been shown that the nature of the surface oxomolybdenum phase strongly depends on the nature of the starting salt. After sulfidation under H₂/H₂S, the performances of these new catalysts have been evaluated in hydrodesulfuration of thiophene. It appears that the cobalt salt of the decamolybdocobaltate anion [Co₂Mo₁₀O₃₈H₄]⁶⁻, with a Co/Mo ratio equal to 0.5, allows us to improve the catalytic conversion by comparison to reference catalysts prepared with ammonium heptamolybdate and cobalt nitrate as starting materials. It has been shown that this improvement is due to the preservation of the heteropolyanionic structure up to the drying step.     

A new CAD mesh segmentation method, based on curvature tensor analysis

This paper presents a new and efficient algorithm for the decomposition of 3D arbitrary triangle meshes and particularly optimized triangulated CAD meshes. The algorithm is based on the curvature tensor field analysis and presents two distinct complementary steps: a region based segmentation, which is an improvement of that presented by Lavoue et al. [Lavoue G, Dupont F, Baskurt A. Constant curvature region decomposition of 3D-meshes by a mixed approach vertex-triangle, J WSCG 2004;12(2):245-52] and which decomposes the object into near constant curvature patches, and a boundary rectification based on curvature tensor directions, which corrects boundaries by suppressing their artefacts or discontinuities. Experiments conducted on various models including both CAD and natural objects, show satisfactory results. Resulting segmented patches, by virtue of their properties (homogeneous curvature, clean boundaries) are particularly adapted to computer graphics tasks like parametric or subdivision surface fitting in an adaptive compression objective.     

Firm strategic profile and IT outsourcing

IT outsourcing research has often been at the transaction level, focusing on the role of the characteristics of the IT activities as the antecedents of outsourcing decisions. The present study extends past research efforts examining the relationships between organizational level variables—in particular the business strategy—and the decision to outsource. Results show that prospectors and analyzers are more aggressive in their use of outsourcing for IT operations. However, no differences between the behaviour of the different strategic groups were found for maintenance activities, suggesting that these activities are too far from the core of the organization to be influenced by strategic profile.

SweetWiki: A semantic wiki

Everyone agrees that user interactions and social networks are among the cornerstones of “Web 2.0”. Web 2.0 applications generally run in a web browser, propose dynamic content with rich user interfaces, offer means to easily add or edit content of the web site they belong to and present social network aspects. Well-known applications that have helped spread Web 2.0 are blogs, wikis, and image/video sharing sites; they have dramatically increased sharing and participation among web users. It is possible to build knowledge using tools that can help analyze users’ behavior behind the scenes: what they do, what they know, what they want. Tools that help share this knowledge across a network, and that can reason on that knowledge, will lead to users who can better use the knowledge available, i.e., to smarter users. Wikipedia, a wildly successful example of web technology, has helped knowledge-sharing between people by letting individuals freely create and modify its content. But Wikipedia is designed for people—today's software cannot understand and reason on Wikipedia's content. In parallel, the “semantic web”, a set of technologies that help knowledge-sharing across the web between different applications, is starting to gain attraction. Researchers have only recently started working on the concept of a “semantic wiki”, mixing the advantages of the wiki and the technologies of the semantic web. In this paper we will present a state-of-the-art of semantic wikis, and we will introduce SweetWiki, an example of an application reconciling two trends of the future web: a semantically augmented web and a web of social applications where every user is an active provider as well as a consumer of information. SweetWiki makes heavy use of semantic web concepts and languages, and demonstrates how the use of such paradigms can improve navigation, search, and usability.