4,115 research outputs found

    Elements of Design for Containers and Solutions in the LinBox Library

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    We describe in this paper new design techniques used in the \cpp exact linear algebra library \linbox, intended to make the library safer and easier to use, while keeping it generic and efficient. First, we review the new simplified structure for containers, based on our \emph{founding scope allocation} model. We explain design choices and their impact on coding: unification of our matrix classes, clearer model for matrices and submatrices, \etc Then we present a variation of the \emph{strategy} design pattern that is comprised of a controller--plugin system: the controller (solution) chooses among plug-ins (algorithms) that always call back the controllers for subtasks. We give examples using the solution \mul. Finally we present a benchmark architecture that serves two purposes: Providing the user with easier ways to produce graphs; Creating a framework for automatically tuning the library and supporting regression testing.Comment: 8 pages, 4th International Congress on Mathematical Software, Seoul : Korea, Republic Of (2014

    Do we need a zero pure time preference or the risk of climate catastrophes to justify a 2C global warming target ?

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    This paper confronts the wide political support for the 2C objective of global increase in temperature, reaffirmed in Copenhagen, with the consistent set of hypotheses on which it relies. It explains why neither an almost zero pure time preference nor concerns about catastrophic damages in case of uncontrolled global warming are prerequisites for policy decisions preserving the possibility of meeting a 2C target. It rests on an optimal stochastic control model balancing the costs and benefits of climate policies resolved sequentially in order to account for the arrival of new information (the RESPONSE model). This model describes the optimal abatement pathways for 2,304 worldviews, combining hypotheses about growth rates, baseline emissions, abatement costs, pure time preference, damages, and climate sensitivity. It shows that 26 percent of the worldviews selecting the 2C target are not characterized by one of the extreme assumptions about pure time preference or climate change damages.Climate Change Mitigation and Green House Gases,Climate Change Economics,Science of Climate Change,Global Environment Facility,Environment and Energy Efficiency

    From volatility smiles to the volatility of volatility

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    Social studies in West German schools

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    Includes bibliographical references and index.The authors describe the process and results of the implementation of a social sciences curriculum in German schools after World War II, and compares this curriculum with that of American schools.Authority and the unpolitical German : The cultural context of German "politische Bildung" -- The contemporary political-educational context -- The school system -- The new "politische Bildung" : The curriculum plans of the Social Democratic Party -- The curriculum -- Instructional goals -- Methods, materials, and classroom tone -- Education of teachers -- Questions for social-studies educators -- Glossary of German terms.Digitized at the University of Missouri--Columbia MU Libraries Digitization Lab in 2013. Digitized at 600 dpi with Zeutschel, OS 15000 scanner. Access copy, available in MOspace, is 400 dpi, grayscale

    Translating standard process models to BPEL

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    Standardisation of languages in the field of business process management has long been an elusive goal. Recently though, consensus has built around one process implementation language, namely BPEL, and two fundamentally similar process modelling notations, namely UML Activity Diagram (UML AD) and BPMN. This paper presents a technique for generating BPEL code from process models expressed in a core subset of BPMN and UML AD. This model-to-code translation is a necessary ingredient to the emergence of model-driven business process development environments based on these standards. The proposed translation has been implemented as an open source tool

    Near-infrared spatially resolved spectroscopy of (136108) Haumea's multiple system

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    The transneptunian region of the solar system is populated by a wide variety of icy bodies showing great diversity. The dwarf planet (136108) Haumea is among the largest TNOs and displays a highly elongated shape and hosts two moons, covered with crystalline water ice like Hamuea. Haumea is also the largest member of the sole TNO family known to date. A catastrophic collision is likely responsible for its unique characteristics. We report here on the analysis of a new set of observations of Haumea obtained with SINFONI at the ESO VLT. Combined with previous data, and using light-curve measurements in the optical and far infrared, we carry out a rotationally resolved spectroscopic study of the surface of Haumea. We describe the physical characteristics of the crystalline water ice present on the surface of Haumea for both regions, in and out of the Dark Red Spot (DRS), and analyze the differences obtained for each individual spectrum. The presence of crystalline water ice is confirmed over more than half of the surface of Haumea. Our measurements of the average spectral slope confirm the redder characteristic of the spot region. Detailed analysis of the crystalline water-ice absorption bands do not show significant differences between the DRS and the remaining part of the surface. We also present the results of applying Hapke modeling to our data set. The best spectral fit is obtained with a mixture of crystalline water ice (grain sizes smaller than 60 micron) with a few percent of amorphous carbon. Improvements to the fit are obtained by adding ~10% of amorphous water ice. Additionally, we used the IFU-reconstructed images to measure the relative astrometric position of the largest satellite Hi`iaka and determine its orbital elements. An orbital solution was computed with our genetic-based algorithm GENOID and our results are in full agreement with recent results.Comment: Accepted for publication in A&

    Extreme AO Observations of Two Triple Asteroid Systems with SPHERE

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    We present the discovery of a new satellite of asteroid (130) Elektra - S/2014 (130) 1 - in differential imaging and in integral field spectroscopy data over multiple epochs obtained with SPHERE/VLT. This new (second) moonlet of Elektra is about 2 km across, on an eccentric orbit and about 500 km away from the primary. For a comparative study, we also observed another triple asteroid system (93) Minerva. For both systems, component-resolved reflectance spectra of the satellites and primary were obtained simultaneously. No significant spectral difference was observed between the satellites and the primary for either triple system. We find that the moonlets in both systems are more likely to have been created by sub-disruptive impacts as opposed to having been captured.Comment: 8 pages, 4 figures, 1 table, accepted to be published in the Astrophysical Journal Letter

    Photoinduced oxidation of sea salt halides by aromatic ketones: a source of halogenated radicals

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    The interactions between triplet state benzophenone and halide anion species (Cl<sup&minu;</sup>, Br<sup&minu;</sup> and I<sup&minu;</sup> have been studied by laser flash photolysis (at 355 nm) in aqueous solutions at room temperature. The decay of the triplet state of benzophenone was followed at 525 nm. Triplet lifetime measurements gave rate constants, <i>k<sub>q</sub></i> (M<sup>−1</sup> s<sup−1</sup>), close to diffusion controlled limit for iodide (~8×10<sup>9</sup> M<sup>−1</sup> s<sup−1</sup>), somewhat less for bromide (~3×10<sup>8</sup> M<sup>−1</sup> s<sup−1</sup>) and much lower for chloride (<10<sup>6</sup> M<sup>−1</sup> s<sup−1</sup>). The halide (X<sup>−</sup>) quenches the triplet state; the resulting product has a transient absorption at 355 nm and a lifetime much longer than that of the benzophenone triplet state, is formed. This transient absorption feature matches those of the corresponding radical anion (X<sub>2</sub><sup&minu;</sup>). We therefore suggest that such reactive quenching is a photosensitized source of halogen in the atmosphere or the driving force for the chemical oxidation of the oceanic surface micro layer
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