630 research outputs found
Data-driven Modeling and Coordination of Large Process Structures
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
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
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
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
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
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
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 HCS and HCS in four interacting excited vibrational states and an account on the rotational spectrum of thioketene, HCCS
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 HCS and HCS 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 HCS 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 HCS and HCS. The HCS data
were supplemented with two sets of high-resultion IR data in two separate
analyses. The state has been included in analyses of Coriolis
interactions of low-lying fundamental states of HCS for the first time and
this improved the quality of the fits substantially. We extended furthermore
assignments in 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?
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
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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