86 research outputs found
Automatic Identification of Structural Process Weaknesses – Experiences with Semantic Business Process Modeling in the Financial Sector
Business process reengineering (BPR) has been a core research topic for at least the last twenty years. As banks have realized the need to look on their business in a process-oriented way, they have been engaged in numerous business process reengineering projects to make their organizations more efficient. However, the success of BPR projects in banks varies significantly and it remains a challenge to systematically discover weaknesses in business process landscapes. Based on the Semantic Business Process Modeling Language (SBPML) this paper introduces a new approach for pattern-based automatic process model analysis, with a focus on identifying structural process weaknesses such as organizational process fragmentation, possibly unnecessary process complexity or multiple resource usage or other process inefficiencies. Additionally, this approach also allows for a benchmarking of different process path alternatives in the same process or among different processes. In this article, this approach is applied and evaluated in the financial sector, but it can possibly also be used in other domains. It contributes to a more efficient and more effective identification of possible weaknesses in process models in comparison to today’s manual analysis of process models
Three regimes of CO emission in galaxy mergers
The conversion factor from the observable CO(1-0)
luminosity to the mass of molecular gas is known to vary between isolated
galaxies and some mergers, but the underlying reasons are not clearly
understood. Thus, the value(s) of to be adopted remain highly
uncertain. To provide better constraints, we apply the large velocity gradient
method to a series of hydrodynamical simulations of galaxies and derive the
evolution of . We report significant variations of
, and identify three distinct regimes: disk galaxies,
starbursts and post-burst phases. We show that estimating the star formation
rate over 20 Myr smooths out some of these differences, but still maintains a
distinction between disks and starbursts. We find a tighter correlation of
with the gas depletion time than with star formation rate,
yet with deviations induced by the transitions to and from the starburst
episodes. We conclude that fluctuates because of both the
feedback energy and the velocity dispersion. Identifying the phase of an
interaction by classical means (e.g. morphology, luminosity) could then help
selecting the relevant conversion factor to be used and get more accurate
estimates of the molecular masses of galaxies.Comment: A&A accepted, 6 pages, 5 figure
Exploring the Status Quo of Business Process Modelling Languages in the Banking Sector – An Empirical Insight into The Usage of Methods in Banks
There are many business process modelling languages (BPML) available on the market for business process modelling. To date, however, it remains unclear how satisfied institutions are with various modelling languages as there is a lack of studies on modelling and analyzing business processes. In order to provide a better understanding of this issue, an exploratory survey with a focus on the banking sector was conducted. Due to a structural crisis in the financial sector (esp. in Germany, where the market is seen as “over-banked” and “over- branched”), banks are currently forced to improve their business processes to save costs and work more efficiently. Thus, they focus on business process management (BPM) and in particular on the preliminary steps of business process modelling. In this paper, key findings from a survey are presented and discussed as a basis for a more sophisticated approach to business process modelling and analysis in the future and also as an insight into the state of the art of business process modelling in general
First Detection of Ammonia in the Large Magellanic Cloud: The Kinetic Temperature of Dense Molecular Cores in N159W
The first detection of ammonia (NH3) is reported from the Magellanic Clouds.
Using the Australia Telescope Compact Array, we present a targeted search for
the (J,K) = (1,1) and (2,2) inversion lines towards seven prominent
star-forming regions in the Large Magellanic Cloud (LMC). Both lines are
detected in the massive star-forming region N159W, which is located in the
peculiar molecular ridge south of 30 Doradus, a site of extreme star formation
strongly influenced by an interaction with the Milky Way halo. Using the
ammonia lines, we derive a kinetic temperature of ~16K, which is 2-3 times
below the previously derived dust temperature. The ammonia column density,
averaged over ~17" is ~6x10^{12} cm^{-2} <1.5x10^{13} cm^{-2} over 9" in the
other six sources) and we derive an ammonia abundance of ~4x10^{-10} with
respect to molecular hydrogen. This fractional abundance is 1.5-5 orders of
magnitude below those observed in Galactic star-forming regions. The nitrogen
abundance in the LMC (~10% solar) and the high UV flux, which can
photo-dissociate the particularly fragile NH3 molecule, must both contribute to
the low fractional NH3 abundance, and we likely only see the molecule in an
ensemble of the densest, best shielded cores of the LMC.Comment: 7 pages, 2 figures, 2 tables, accepted for publication in the
Astrophysical Journa
Dense Molecular Gas Excitation in Nuclear Starbursts at High Redshift: HCN, HNC, and HCO+(J=6-5) Emission in the z=3.91 Quasar Host of APM08279+5255
We report the detection of surprisingly strong HCN, HNC, and HCO+(J=6-5)
emission in the host galaxy of the z=3.91 quasar APM08279+5255 through
observations with CARMA. HCN, HNC, and HCO+ are typically used as star
formation indicators, tracing dense molecular hydrogen gas [n(H2) > 10^5,cm^-3]
within star-forming molecular clouds. However, the strength of their respective
line emission in the J=6-5 transitions in APM08279+5255 is extremely high,
suggesting that they are excited by another mechanism besides collisions in the
dense molecular gas phase alone. We derive J=6-5 line luminosities of
L'(HCN)=(4.9+/-0.6), L'(HNC)=(2.4+/-0.7), and L'(HCO+)=(3.0+/-0.6)x10^10
(mu_L)^-1 K km/s pc^2 (where mu_L is the lensing magnification factor),
corresponding to L' ratios of ~0.23-0.46 relative to CO(J=1-0). Such high line
ratios would be unusual even in the respective ground-state (J=1-0)
transitions, and indicate exceptional, collisionally and radiatively driven
excitation conditions in the dense, star-forming molecular gas in
APM08279+5255. Through an expansion of our previous modeling of the HCN line
excitation in this source, we show that the high rotational line fluxes are
caused by substantial infrared pumping at moderate opacities in a ~220K warm
gas and dust component. This implies that standard M_dense/L' conversion
factors would substantially overpredict the dense molecular gas mass M_dense.
We also find a HCN J=6-5/5-4 L' ratio greater than 1 (1.36+/-0.31) - however,
our models show that the excitation is likely not `super-thermal', but that the
high line ratio is due to a rising optical depth between both transitions.
These findings are consistent with the picture that the bulk of the gas and
dust in this source is situated in a compact, nuclear starburst, where both the
highly active galactic nucleus and star formation contribute to the heating.Comment: 8 pages, 5 figures, to appear in ApJ (accepted October 8, 2010
Detection of [O III] at z~3: A Galaxy above the Main Sequence, Rapidly Assembling its Stellar Mass
We detect bright emission in the far infrared fine structure [O III] 88m
line from a strong lensing candidate galaxy, H-ATLAS J113526.3-014605,
hereafter G12v2.43, at z=3.127, using the generation Redshift (z)
and Early Universe Spectrometer (ZEUS-2) at the Atacama Pathfinder Experiment
Telescope (APEX). This is only the fifth detection of this far-IR line from a
sub-millimeter galaxy at the epoch of galaxy assembly. The observed [O III]
luminosity of likely
arises from HII regions around massive stars, and the amount of Lyman continuum
photons required to support the ionization indicate the presence of
equivalent O5.5 or higher stars;
where would be the lensing magnification factor. The observed line
luminosity also requires a minimum mass of in ionized gas, that is
of the estimated total molecular gas mass of
. We compile multi-band
photometry tracing rest-frame UV to millimeter continuum emission to further
constrain the properties of this dusty high redshift star-forming galaxy. Via
SED modeling we find G12v2.43 is forming stars at a rate of 916
and already has a stellar
mass of . We also
constrain the age of the current starburst to be 5 million years,
making G12v2.43 a gas rich galaxy lying above the star-forming main sequence at
z3, undergoing a growth spurt and, could be on the main sequence within
the derived gas depletion timescale of 66 million years.Comment: 11 pages, 3 figures, accepted for publication in The Astrophysical
Journa
A Sensitive Search For [NII] Emission in a z=6.4 Quasar Host Galaxy
We present a sensitive search for the ^3P_1->^3P_0 ground state fine
structure line at 205 microns of ionized nitrogen ([NII]) in one of the highest
redshift quasars (J1148+5251 at z=6.42) using the IRAM 30m telescope. The line
is not detected at a (3 sigma) depth of 0.47 Jy km s^-1, corresponding to a
[NII] luminosity limit of L_[NII] < 4.0x10^8 L_sun and a L_[NII]/L$_FIR ratio
of <2x10^-5. In parallel, we have observed the CO(J=6-5) line in J1148+5251,
which is detected at a flux level consistent with earlier interferometric
observations. Using our earlier measurements of the [CII] 158 micron line
strength, we derive an upper limit for the [NII]/[CII] line luminosity ratio of
~1/10 in J1148+5251. Our upper limit for the [CII]/[NII] ratio is similar to
the value found for our Galaxy and M82 (the only extragalactic system where the
[NII] line has been detected to date). Given the non-detection of the [NII]
line we can only speculate whether or not high-z detections are within reach of
currently operating observatories. However, [NII] and other fine strucure lines
will play a critical role in characterizing the interstellar medium at the
highest redshifts (z>7) using the Atacama Large Millimeter/submillimeter Array
(ALMA), for which the highly excited rotational transitions of CO will be
shifted outside the accessible (sub-)millimeter bands.Comment: Accepted for publication in the ApJ Letter
The Molecular Ridge Close to 30 Doradus in the Large Magellanic Cloud
With the ATNF Mopra telescope we are performing a survey in the 12CO(1-0)
line to map the molecular gas in the Large Magellanic Cloud (LMC). For some
regions we also obtained interferometric maps of the high density gas tracers
HCO+ and HCN with the Australia Telescope Compact Array (ATCA). Here we discuss
the properties of the elongated molecular complex that stretches about 2 kpc
southward from 30 Doradus. Our data suggests that the complex, which we refer
to as the ``molecular ridge,'' is not a coherent feature but consists of many
smaller clumps that share the same formation history. Likely molecular cloud
formation triggers are shocks and shearing forces that are present in the
surrounding south-eastern HI overdensity region, a region influenced by strong
ram pressure and tidal forces. The molecular ridge is at the western edge of
the the overdensity region where a bifurcated velocity structure transitions
into a single disk velocity component. We find that the 12CO(1-0) and HI
emission peaks in the molecular ridge are typically near each other but never
coincide. A likely explanation is the conversion of warmer, low-opacity HI to
colder, high-opacity HI from which H2 subsequently forms. On smaller scales, we
find that very dense molecular gas, as traced by interferometric HCO+ and HCN
maps, is associated with star formation along shocked filaments and with rims
of expanding shell-like structures, both created by feedback from massive
stars.Comment: accepted for publication in the Publications of the Astronomical
Society of Australi
The Molecular ISM in the Super Star Clusters of the Starburst NGC 253
We present submillimeter spectra of the (proto-)super star cluster (SSC)
candidates in the starbursting center of the nearby galaxy NGC 253 identified
by Leroy et al. (2018). The 2.5pc resolution of our ALMA cycle 3 observations
approach the size of the SSCs and allows the study of physical and chemical
properties of the molecular gas in these sources. In the 14 SSC sources and in
the frequency ranges 342.0-345.8 GHz and 353.9-357.7 GHz we detect 55 lines
belonging to 19 different chemical species. The SSCs differ significantly in
chemical complexity, with the richest clusters showing 19 species and the least
complex showing 4 species. We detect HCN isotopologues and isomers (HCN,
HCN, HNC), abundant HCN, SO and SO, SO, and
HCS. The gas ratios CO/HCN, CO/HCO are low, ~1-10, implying high dense
gas fractions in the SSCs. Line ratio analyses suggests chemistry consistent
with photon-dominated regions and mechanical heating. None of the SSCs near the
galaxy center show line ratios that imply an X-ray dominated region, suggesting
that heating by any (still unknown) AGN does not play a major role. The gas
temperatures are high in most sources, with an average rotational temperature
of ~130 K in SO. The widespread existence of vibrationally excited HCN and
HCN transitions implies strong IR radiation fields, potentially trapped by
a greenhouse effect due to high continuum opacities.Comment: 20 pages, 4 figures, 6 tables; accepted for publication in the
Astrophysical Journa
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