44,334 research outputs found

    Infrared regulators and SCETII

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    We consider matching from SCETI, which includes ultrasoft and collinear particles, onto SCETII with soft and collinear particles at one loop. Keeping the external fermions off their mass shell does not regulate all IR divergences in both theories. We give a new prescription to regulate infrared divergences in SCET. Using this regulator, we show that soft and collinear modes in SCETII are sufficient to reproduce all the infrared divergences of SCETI. We explain the relationship between IR regulators and an additional mode proposed for SCETII.Comment: 9 pages. Added discussion about relationship between IR regulators and messenger mode

    An Approach for Supporting Ad-hoc Modifications in Distributed Workflow Management Systems

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    Supporting enterprise-wide or even cross-organizational business processes is a characteristic challenge for any workflow management system (WfMS). Scalability at the presence of high loads as well as the capability to dynamically modify running workflow (WF) instances (e.g., to cope with exceptional situations) are essential requirements in this context. Should the latter one, in particular, not be met, the WfMS will not have the necessary flexibility to cover the wide range of process-oriented applications deployed in many organizations. Scalability and flexibility have, for the most part, been treated separately in the relevant literature thus far. Even though they are basic needs for a WfMS, the requirements related with them are totally different. To achieve satisfactory scalability, on the one hand, the system needs to be designed such that a workflow instance can be controlled by several WF servers that are as independent from each other as possible. Yet dynamic WF modifications, on the other hand, necessitate a (logical) central control instance which knows the current and global state of a WF instance. For the first time, this paper presents methods which allow ad-hoc modifications (e.g., to insert, delete, or shift steps) to be performed in a distributed WfMS; i.e., in a WfMS with partitioned WF execution graphs and distributed WF control. It is especially noteworthy that the system succeeds in realizing the full functionality as given in the central case while, at the same time, achieving extremely favorable behavior with respect to communication costs

    Plasma Formation Dynamics in Intense Laser-Droplet Interaction

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    We study the ionization dynamics in intense laser-droplet interaction using three-dimensional, relativistic particle-in-cell simulations. Of particular interest is the laser intensity and frequency regime for which initially transparent, wavelength-sized targets are not homogeneously ionized. Instead, the charge distribution changes both in space and in time on a sub-cycle scale. One may call this the extreme nonlinear Mie-optics regime. We find that - despite the fact that the plasma created at the droplet surface is overdense - oscillating electric fields may penetrate into the droplet under a certain angle, ionize, and propagate in the just generated plasma. This effect can be attributed to the local field enhancements at the droplet surface predicted by standard Mie theory. The penetration of the fields into the droplet leads to the formation of a highly inhomogeneous charge density distribution in the droplet interior, concentrated mostly in the polarization plane. We present a self-similar, exponential fit of the fractional ionization degree which depends only on a dimensionless combination of electric field amplitude, droplet radius, and plasma frequency with only a weak dependence on the laser frequency in the overdense regime.Comment: 5 pages, 6 figure

    Magnetic moment of the Roper resonance

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    The magnetic moment of the Roper resonance is calculated in the framework of a low-energy effective field theory of the strong interactions. A systematic power-counting procedure is implemented by applying the complex-mass scheme.Comment: 13 pages, 4 figure

    Parameterizable Views for Process Visualization

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    In large organizations different users or user groups usually have distinguished perspectives over business processes and related data. Personalized views on the managed processes are therefore needed. Existing BPM tools, however, do not provide adequate mechanisms for building and visualizing such views. Very often processes are displayed to users in the same way as drawn by the process designer. To tackle this inflexibility this paper presents an advanced approach for creating personalized process views based on well-defined, parameterizable view operations. Respective operations can be flexibly composed in order to reduce or aggregate process information in the desired way. Depending on the chosen parameterization of the applied view operations, in addition, different "quality levels" with more or less relaxed properties can be obtained for the resulting process views (e.g., regarding the correctness of the created process view scheme). This allows us to consider the specific needs of the different applications utilizing process views (e.g., process monitoring tools or process editors). Altogether, the realized view concept contributes to better deal with complex, long-running business processes with hundreds up to thousands of activities

    Measuring the degree of virtualization. An empirical analysis in two Austrian industries.

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    Strategic management literature suggests that especially in young and dynamic industries Virtual Corporations are more likely to emerge, as this type of organization is flexible enough to deal with rapidly changing environments. This paper challenges the proposition that environ-mental uncertainty and technological change lead to organizational adaptation towards virtual structures. We analyzed companies of two Austrian industries, data processing and engineering, which are characterized by different rates of innovation and environmental uncertainty, and compare their strategic, structural, and process characteristics by measuring their Degree of Virtualization. Results indicate almost no difference in the Degree of Virtualization. From these findings, we draw implications for the theoretical concept of Virtual Corpora-tions as well as for empirical research. (author's abstract)Series: Report Series SFB "Adaptive Information Systems and Modelling in Economics and Management Science

    Electromagnetic form factors of the nucleon in effective field theory

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    We calculate the electromagnetic form factors of the nucleon to third chiral order in manifestly Lorentz-invariant effective field theory. The rho and omega mesons as well as the Delta(1232) resonance are included as explicit dynamical degrees of freedom. To obtain a self-consistent theory with respect to constraints we consider the proper relations among the couplings of the effective Lagrangian. For the purpose of generating a systematic power counting, the extended on-mass-shell renormalization scheme is applied in combination with the small-scale expansion. The results for the electric and magnetic Sachs form factors are analyzed in terms of experimental data and compared to previous findings in the framework of chiral perturbation theory. The pion-mass dependence of the form factors is briefly discussed.Comment: 26 pages, 9 figure
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