6,383 research outputs found
Beyond Control-Flow: Extending Business Process Configuration to Roles and Objects
A configurable process model is an integrated representation of multiple variants of a business process. It is designed to be individualized to meet a particular set of requirements. As such, configurable process models promote systematic reuse of proven or common practices. Existing notations for configurable process modeling focus on capturing tasks and control-flow dependencies, neglecting equally important aspects of business processes such as data flow, material flow and resource management. This paper fills this gap by proposing an integrated meta-model for configurable processes with advanced features for capturing resources involved in the performance of tasks (through task-role associations) as well as flow of data and physical artifacts (through task-object associations). Although embodied as an extension of a popular process modeling notation, namely EPC, the meta-model is defined in an abstract and formal manner to make it applicable to other notations
Dynamical Backreaction in Robertson-Walker Spacetime
The treatment of a quantized field in a curved spacetime requires the study
of backreaction of the field on the spacetime via the semiclassical Einstein
equation. We consider a free scalar field in spatially flat Robertson-Walker
space time. We require the state of the field to allow for a renormalized
semiclassical stress tensor. We calculate the sigularities of the stress tensor
restricted to equal times in agreement with the usual renormalization
prescription for Hadamard states to perform an explicit renormalization. The
dynamical system for the Robertson Walker scale parameter coupled to the
scalar field is finally derived for the case of conformal and also general
coupling.Comment: Obtained equation of motion for non-conformal coupling, not just
counter terms as in previous version. Typos fixed, renormalization term
proportional to R adde
Beam Test of BTeV Pixel Detectors
The silicon pixel vertex detector is one of the key elements of the BTeV
spectrometer. Detector prototypes were tested in a beam at Fermilab. We report
here on the measured spatial resolution as a function of the incident angles
for different sensor-readout electronics combinations. We compare the results
with predictions from our Monte Carlo simulation.Comment: 7 pages, 5 figures, Invited talk given by J.C. Wang at "Vertex 2000,
9th International Workshop on Vertex Detectors", Michigan, Sept 10-15, 2000.
To be published in NIM
On Hausdorff dimension of the set of closed orbits for a cylindrical transformation
We deal with Besicovitch's problem of existence of discrete orbits for
transitive cylindrical transformations
where is an
irrational rotation on the circle \T and \varphi:\T\to\R is continuous,
i.e.\ we try to estimate how big can be the set
D(\alpha,\varphi):=\{x\in\T:|\varphi^{(n)}(x)|\to+\infty\text{as}|n|\to+\infty\}.
We show that for almost every there exists such that the
Hausdorff dimension of is at least . We also provide a
Diophantine condition on that guarantees the existence of
such that the dimension of is positive. Finally, for some
multidimensional rotations on \T^d, , we construct smooth
so that the Hausdorff dimension of is positive.Comment: 32 pages, 1 figur
Changes in specific metabolic pathways are essential steps in the early apoptotic process in the liver
the immunosuppressant Cyclosporine A (CsA), we used multinuclear NMR spectroscopy and molecular studies to characterize metabolic pathways in mice liver during anti-Fas-induced apoptosis. An upregulation of specific metabolic pathways of glucose was the earliest indicator of the effect of Fas on the liver. CsA prevented apoptosis and energy failure at late stages, while the reversal of Fas-induced metabolic upregulation at early stages preceded the protective effect of EGF on programmed cell death. These phenomena provide useful hints for the understanding of early mechanisms controlling apoptotic cell death
Flexible and reusable parylene C mask technology for applications in cascade impactor air quality monitoring systems
The development of traceable new methodologies to quantify elemental air pollutants in particulate matter (PM) supports modernization of methods used in air quality monitoring networks in Europe. In the framework of the EURAMET EMPIR AEROMET II project, the combination of cascade impactor aerosol sampling and total reflection X-ray fluorescence elemental spectroscopy (TXRF) was investigated. This technique requires a traceable calibration based on reference samples. This paper describes a new, simple and effective method to produce such reference samples using flexible, reusable, and low-cost parylene C shadow masks, fabricated by photolithographic steps. These shadow masks can be used to produce reference samples that mimic the Dekati cascade impactor's deposition patterns by applying as-prepared micro stencils to 30 mm acrylic substrates and evaporating a reference material (Ti) in arrangements of thin circular dots. The highly flexible direct patterning of acrylic discs with reference material, otherwise impossible with conventional photolithography, allows multiple reusing of the same micro stencils. The aspect ratios of the dots could be repeated with an error less than 4%. A first set of standard reference samples for the 13 stages of the Dekati cascade impactor was produced and preliminary TXRF measurements of the deposited Ti masses were performed. The centricity of the deposition patterns turned out to be an important parameter for the quality of the TXRF results. The parylene mask technology for the production of reference samples turns out to be a promising new approach for the traceable calibration of TXRF spectrometers for the quantification of element concentrations in environmental aerosol samples but, due to its great versatility, it could be used for several other micropatterning applications on conventional and unconventional substrates
- …