630 research outputs found

    Data-driven Modeling and Coordination of Large Process Structures

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    In the engineering domain, the development of complex products (e.g., cars) necessitates the coordination of thousands of (sub-)processes. One of the biggest challenges for process management systems is to support the modeling, monitoring and maintenance of the many interdependencies between these sub-processes. The resulting process structures are large and can be characterized by a strong relationship with the assembly of the product; i.e., the sub-processes to be coordinated can be related to the different product components. So far, sub-process coordination has been mainly accomplished manually, resulting in high efforts and inconsistencies. IT support is required to utilize the information about the product and its structure for deriving, coordinating and maintaining such data-driven process structures. In this paper, we introduce the COREPRO framework for the data-driven modeling of large process structures. The approach reduces modeling efforts significantly and provides mechanisms for maintaining data-driven process structures

    Data-driven Design of Engineering Processes with COREPROModeler

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    Enterprises increasingly demand IT support for the coordination of their engineering processes, which often consist of hundreds up to thousands of sub-processes. From a technical viewpoint, these sub-processes have to be concurrently executed and synchronized considering numerous interdependencies. So far, this coordination has mainly been accomplished manually, which has resulted in errors and inconsistencies. In order to deal with this problem, we have to better understand the interdependencies between the subprocesses to be coordinated. In particular, we can benefit from the fact that sub-processes are often correlated to the assembly of a product (represented by a product data structure). This information can be utilized for the modeling and execution of so-called data-driven process structures. In this paper, we present the COREPRO demonstrator that supports the data-driven modeling of these process structures. The approach explicitly establishes a close linkage between product data structures and engineering processes

    LIINUS/SERPIL: a design study for interferometric imaging spectroscopy at the LBT

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    LIINUS/SERPIL is a design study to augment LBTs interferometric beam combiner camera LINC-NIRVANA with imaging spectroscopy. The FWHM of the interferometric main beam at 1.5 micron will be about 10 mas, offering unique imaging and spectroscopic capabilities well beyond the angular resolution of current 8-10m telescopes. At 10 mas angular scale, e.g., one resolution element at the distance of the Galactic Center corresponds to the average diameter of the Pluto orbit (79 AU), hence the size of the solar system. Taking advantage of the LBT interferometric beam with an equivalent maximum diameter of 23 m, LIINUS/SERPIL is an ideal precursor instrument for (imaging) spectrographs at extremely large full aperture telescopes. LIINUS/SERPIL will be built upon the LINC-NIRVANA hardware and LIINUS/SERPIL could potentially be developed on a rather short timescale. The study investigates several concepts for the optical as well as for the mechanical design. We present the scientific promises of such an instrument together with the current status of the design study.Comment: 12 pages, SPIE conference proceeding, Orlando, 200

    COREPRO-Sim: A Tool for Modeling, Simulating and Adapting Data-driven Process Structures

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    Industry is increasingly demanding IT support for large engineering process structures consisting of hundreds up to thousands of synchronized processes. In technical domains, such process structures are characterized by their strong relation to the assembly of a product (e.g., a car); i.e., resulting process structures are data-driven. The strong linkage between data and processes can be utilized for automatically creating process structures as well as for (dynamically) adapting them at a high level of abstraction. This paper presents the COREPRO-Sim demonstrator which enables sophisticated support for modeling, coordinating and (dynamically) adapting data-driven process structures. COREPRO-Sim substantiates the COREPRO approach which provides a new paradigm for the integration of data and and process structures

    Local Equation of State and Velocity Distributions of a Driven Granular Gas

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    We present event-driven simulations of a granular gas of inelastic hard disks with incomplete normal restitution in two dimensions between vibrating walls (without gravity). We measure hydrodynamic quantities such as the stress tensor, density and temperature profiles, as well as velocity distributions. Relating the local pressure to the local temperature and local density, we construct a local constitutive equation. For strong inelasticities the local constitutive relation depends on global system parameters, like the volume fraction and the aspect ratio. For moderate inelasticities the constitutive relation is approximately independent of the system parameters and can hence be regarded as a local equation of state, even though the system is highly inhomogeneous with heterogeneous temperature and density profiles arising as a consequence of the energy injection. Concerning the local velocity distributions we find that they do not scale with the square root of the local granular temperature. Moreover the high-velocity tails are different for the distribution of the x- and the y-component of the velocity, and even depend on the position in the sample, the global volume fraction, and the coefficient of restitution.Comment: 14 pages, 14 figures of which Figs. 13a-f and Fig. 14 are archived as separate .gif files due to upload-size limitations. A version of the paper including all figures in better quality can be downloaded at http://www.theorie.physik.uni-goettingen.de/~herbst/download/LocEqSt.ps.gz (3.8 MB, ps.gz) or at http://www.theorie.physik.uni-goettingen.de/~herbst/download/LocEqSt.pdf (4.9 MB, pdf

    Mopra line survey mapping of NGC6334I and I(N) at 3mm

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    A 5'x5' region encompassing NGC6334I and I(N) has been mapped at a wavelength of 3mm (from 83.5 to 115.5GHz) with the Mopra telescope at an angular resolution between 33 arcsec and 36 arcsec. This investigation has made use of the recently installed 3mm MMIC receiver and the Mopra Spectrometer (MOPS) with broadband capabilities permitting total coverage of the entire frequency range with just five different observations. In total, the spatial distribution of nineteen different molecules, ions and radicals, along with additional selected isotopologues have been studied. Whilst most species trace the sites of star formation, CH_3CN appears to be most closely associated with NGC6334I and I(N). Both CN and C_2H appear to be widespread, tracing gas that is not associated with active star formation. Both N_2H^+ and HC_3N closely resemble dust continuum emission, showing they are reliable tracers of dense material, as well as the youngest stages of high mass star formation. Hot (E_u/k>100K) thermal CH_3OH emission is preferentially found towards NGC6334I, contrasting with I(N), where only cold (E_u/k<22K) thermal CH_3OH emission is found.Comment: Accepted by MNRA

    First astronomical detection of the CF+ ion

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    We report the first astronomical detection of the CF+ (fluoromethylidynium) ion obtained by recent observations of its J = 1 - 0 (102.6 GHz), J = 2 - 1 (205.2 GHz), and J = 3 - 2 (307.7 GHz) pure rotational emissions toward the Orion Bar. Our search for CF+, carried out using the IRAM 30m and APEX 12m telescopes, was motivated by recent theoretical models that predict CF+ abundances of a few x E-10 in UV-irradiated molecular regions where C+ is present. The measurements confirm the predictions. They provide support for our current theories of interstellar fluorine chemistry, which suggest that hydrogen fluoride should be ubiquitous in interstellar gas clouds.Comment: 2 pages, 1 figure (uses iaus.sty), to appear in IAU Symposium No. 231, Astrochemistry - Recent Successes and Current Challenges, eds. D. C. Lis, G. A. Blake & E. Herbst (Cambridge Univ. Press

    Rotational spectroscopy of the thioformaldehyde isotopologues H2_2CS and H2_2C34^{34}S in four interacting excited vibrational states and an account on the rotational spectrum of thioketene, H2_2CCS

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    An investigation of the rotational spectrum of the interstellar molecule thioformaldehyde between 110 and 377 GHz through a pyrolysis reaction revealed a multitude of absorption lines assignable to H2_2CS and H2_2C34^{34}S in their lowest four excited vibrational states besides lines of numerous thioformaldehyde isotopologues in their ground vibrational states reported earlier as well as lines pertaining to several by-products. Additional transitions of H2_2CS in its lowest four excited vibrational states were recorded in selected regions between 571 and 1386 GHz. Slight to strong Coriolis interactions occur between all four vibrational states with the exception of the two highest lying states because both are totally symmetric vibrations. We present combined analyses of the ground and the four interacting states for our rotational data of H2_2CS and H2_2C34^{34}S. The H2_2CS data were supplemented with two sets of high-resultion IR data in two separate analyses. The v2=1v_2 = 1 state has been included in analyses of Coriolis interactions of low-lying fundamental states of H2_2CS for the first time and this improved the quality of the fits substantially. We extended furthermore assignments in JJ of transition frequencies of thioketene in its ground vibrational state.Comment: 23 pages including figures, tables, and references; Mol. Phys., accepted (for the Tim Lee memorial issue

    Wie Studierende Formeln gliedern?

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    Die vorgestellte Studie behandelt das Verhalten von Studierenden gegenüber Formeln. Hierbei wurde untersucht wie Studierende vorgelegte Formeln aufteilen, gliedern sowie nach eigenen Vorstellungen neu zusammensetzen und interpretieren. Die Arbeit stellt eine Erweiterung einer bereits mit Schülerinnen und Schülern durchgeführten Studie dar.Die in der ersten Studie gefundenen Kategorien, in denen Formelbestanteile eingeteilt wurden, konnten bestätigt und um zwei Unterkategorien erweitert werden. Die Neustrukturierung der Formeln ergab ähnliche Ergebnisse wie in der ersten Studie. Die Interpretation der Formeln zeigt auch bei Studierenden ein heterogenes Feld

    Arcsecond resolution images of the chemical structure of the low-mass protostar IRAS 16293-2422

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    It remains a key challenge to establish the molecular content of different components of low-mass protostars, like their envelopes and disks, and how this depends on the evolutionary stage and/or environment of the young stars. Observations at submillimeter wavelengths provide a direct possibility to study the chemical composition of low-mass protostars through transitions probing temperatures up to a few hundred K in the gas surrounding these sources. This paper presents a large molecular line survey of the deeply embedded protostellar binary IRAS 16293-2422 from the Submillimeter Array (SMA) - including images of individual lines down to approximately 1.5-3" (190-380 AU) resolution. More than 500 individual transitions are identified related to 54 molecular species (including isotopologues) probing temperatures up to about 550 K. Strong chemical differences are found between the two components in the protostellar system with a separation between, in particular, the sulfur- and nitrogen-bearing species and oxygen-bearing complex organics. The action of protostellar outflow on the ambient envelope material is seen in images of CO and SiO and appear to influence a number of other species, including (deuterated) water, HDO. The effects of cold gas-phase chemistry is directly imaged through maps of CO, N2D+ and DCO+, showing enhancements of first DCO+ and subsequently N2D+ in the outer envelope where CO freezes-out on dust grains.Comment: Accepted for publication in A&A, 30 pages, 22 figure
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