86 research outputs found

    Automatic Identification of Structural Process Weaknesses – Experiences with Semantic Business Process Modeling in the Financial Sector

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    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

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    The conversion factor αCO\alpha_{\rm CO} 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 αCO\alpha_{\rm CO} 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 αCO\alpha_{\rm CO}. We report significant variations of αCO\alpha_{\rm CO}, 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 αCO\alpha_{\rm CO} 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 αCO\alpha_{\rm CO} 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

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    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

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    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

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    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

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    We detect bright emission in the far infrared fine structure [O III] 88μ\mum line from a strong lensing candidate galaxy, H-ATLAS J113526.3-014605, hereafter G12v2.43, at z=3.127, using the 2nd\rm 2^{nd} 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 7.1×109(10μ)L7.1\times10^{9}\,\rm(\frac{10}{\mu})\,\rm{L_{\odot}}\, likely arises from HII regions around massive stars, and the amount of Lyman continuum photons required to support the ionization indicate the presence of (1.25.2)×106(10μ)(1.2-5.2)\times10^{6}\,\rm(\frac{10}{\mu}) equivalent O5.5 or higher stars; where μ\mu would be the lensing magnification factor. The observed line luminosity also requires a minimum mass of 2×108(10μ)M\sim 2\times 10^{8}\,\rm(\frac{10}{\mu})\,\rm{M_{\odot}}\, in ionized gas, that is 0.33%0.33\% of the estimated total molecular gas mass of 6×1010(10μ)M6\times10^{10}\,\rm(\frac{10}{\mu})\,\rm{M_{\odot}}\,. 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 (10μ)Myr1\rm(\frac{10}{\mu})\,\rm{M_{\odot}}\,\rm{yr^{-1}} and already has a stellar mass of 8×1010(10μ)M8\times 10^{10}\,\rm(\frac{10}{\mu})\,\rm{M_{\odot}}\,. We also constrain the age of the current starburst to be \leqslant 5 million years, making G12v2.43 a gas rich galaxy lying above the star-forming main sequence at z\sim3, undergoing a growth spurt and, could be on the main sequence within the derived gas depletion timescale of \sim66 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

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    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

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    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

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    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 (H13^{13}CN, HC15^{15}N, H15^{15}NC), abundant HC3_3N, SO and S18^{18}O, SO2_2, and H2_2CS. 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 SO2_2. The widespread existence of vibrationally excited HCN and HC3_3N 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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