Answering Regular Path Queries on Workflow Provenance

This paper proposes a novel approach for efficiently evaluating regular path queries over provenance graphs of workflows that may include recursion. The approach assumes that an execution g of a workflow G is labeled with query-agnostic reachability labels using an existing technique. At query time, given g, G and a regular path query R, the approach decomposes R into a set of subqueries R1, ..., Rk that are safe for G. For each safe subquery Ri, G is rewritten so that, using the reachability labels of nodes in g, whether or not there is a path which matches Ri between two nodes can be decided in constant time. The results of each safe subquery are then composed, possibly with some small unsafe remainder, to produce an answer to R. The approach results in an algorithm that significantly reduces the number of subqueries k over existing techniques by increasing their size and complexity, and that evaluates each subquery in time bounded by its input and output size. Experimental results demonstrate the benefit of this approach

Numerical aerodynamic simulation facility preliminary study: Executive study

A computing system was designed with the capability of providing an effective throughput of one billion floating point operations per second for three dimensional Navier-Stokes codes. The methodology used in defining the baseline design, and the major elements of the numerical aerodynamic simulation facility are described

Development of paper membrane switches for fully featured computer keyboards

This paper documents the successful development and evaluation of a novel membrane switch. The process results in lower environmental burdens and manufacturing costs than current screen-printed polyester solutions. Detailed is the evaluation of offset lithographically printed conductive tracks on paper substrates for application in computer keyboard assemblies. Offset lithographic printing of conductive tracks is an emerging fabrication technique finding application in low-cost, high volume, flexible circuitry applications. Several fully featured demonstration keyboards and switch membranes have been constructed and tested. These are currently in use in office environments and are presented

Fast and Tiny Structural Self-Indexes for XML

XML document markup is highly repetitive and therefore well compressible using dictionary-based methods such as DAGs or grammars. In the context of selectivity estimation, grammar-compressed trees were used before as synopsis for structural XPath queries. Here a fully-fledged index over such grammars is presented. The index allows to execute arbitrary tree algorithms with a slow-down that is comparable to the space improvement. More interestingly, certain algorithms execute much faster over the index (because no decompression occurs). E.g., for structural XPath count queries, evaluating over the index is faster than previous XPath implementations, often by two orders of magnitude. The index also allows to serialize XML results (including texts) faster than previous systems, by a factor of ca. 2-3. This is due to efficient copy handling of grammar repetitions, and because materialization is totally avoided. In order to compare with twig join implementations, we implemented a materializer which writes out pre-order numbers of result nodes, and show its competitiveness.Comment: 13 page

An industrial scale process for the enzymatic removal of steryl glucosides from biodiesel

Background: Biodiesels produced from transesterification of vegetable oils have a major quality problem due to thepresence of precipitates, which need to be removed to avoid clogging of filters and engine failures. These precipitateshave been reported to be mostly composed of steryl glucosides (SGs), but so far industrial cost-effective methods toremove these compounds are not available. Here we describe a novel method for the efficient removal of SGs frombiodiesel, based on the hydrolytic activity of a thermostable β-glycosidase obtained from Thermococcus litoralis.Results: A steryl glucosidase (SGase) enzyme from T. litoralis was produced and purified from Escherichia coli culturesexpressing a synthetic gene, and used to treat soybean-derived biodiesel. Several optimization steps allowed for theselection of optimal reaction conditions to finally provide a simple and efficient process for the removal of SGs fromcrude biodiesel. The resulting biodiesel displayed filterability properties similar to distilled biodiesel according to thetotal contamination (TC), the cold soak filtration test (CSFT), filter blocking tendency (FBT), and cold soak filter blockingtendency (CSFBT) tests. The process was successfully scaled up to a 20 ton reactor, confirming its adaptability toindustrial settings.Conclusions: The results presented in this work provide a novel path for the removal of steryl glucosides from biodieselusing a cost-effective, environmentally friendly and scalable enzymatic process, contributing to the adoption ofthis renewable fuel.Fil: Peirú, Salvador. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; Argentina. Keclon; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Aguirre, Andres. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; Argentina. Keclon; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Eberhardt, Maria Florencia. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Braia, Mauricio Javier. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Cabrera, Rodolfo Ariel. Unitec Bio; ArgentinaFil: Menzella, Hugo Gabriel. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; Argentina. Keclon; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin