469 research outputs found
Promoting business process management excellence in Russia: Proceedings and report of the PropelleR 2012 Workshop held in Moscow, April 24 to 26, 2012
BPM research has been of great importance in Germany since the early 1990s. In Russia, increased competition and new IT possibilities have only recently forced both companies and governmental institutions to start taking benefits from BPM. Against this background, the workshop PropelleR 2012 brought together German and Russian BPM researchers as well as practitioners in order to discuss recent BPM trends and challenges. The guiding question addressed by PropelleR 2012 was: 'How can the growing complexity of business processes in German-Russian relations be addressed by a holistic BPM approach?' This report includes a set of articles that reflect the PropelleR workshop participants' viewpoints on this question
Cosmic Strings from Supersymmetric Flat Directions
Flat directions are a generic feature of the scalar potential in
supersymmetric gauge field theories. They can arise, for example, from D-terms
associated with an extra abelian gauge symmetry. Even when supersymmetry is
broken softly, there often remain directions in the scalar field space along
which the potential is almost flat. Upon breaking a gauge symmetry along one of
these almost flat directions, cosmic strings may form. Relative to the standard
cosmic string picture based on the abelian Higgs model, these flat-direction
cosmic strings have the extreme Type-I properties of a thin gauge core
surrounded by a much wider scalar field profile. We perform a comprehensive
study of the microscopic, macroscopic, and observational characteristics of
this class of strings. We find many differences from the standard string
scenario, including stable higher winding mode strings, the dynamical formation
of higher mode strings from lower ones, and a resultant multi-tension scaling
string network in the early universe. These strings are only moderately
constrained by current observations, and their gravitational wave signatures
may be detectable at future gravity wave detectors. Furthermore, there is the
interesting but speculative prospect that the decays of cosmic string loops in
the early universe could be a source of ultra-high energy cosmic rays or
non-thermal dark matter. We also compare the observational signatures of
flat-direction cosmic strings with those of ordinary cosmic strings as well as
(p,q) cosmic strings motivated by superstring theory.Comment: 58 pages, 16 figures, v2. accepted to PRD, added comments about
baryogenesis and boosted decay products from cusp annihilatio
A Test of Star Formation Laws in Disk Galaxies
We use observations of the radial profiles of the mass surface density of
total, Sigma_g, and molecular, Sigma_H2, gas, rotation velocity and star
formation rate surface density, Sigma_sfr, of the molecular dominated regions
of 12 disk galaxies from Leroy et al. to test several star formation laws: a
"Kennicutt-Schmidt power law", Sigma_sfr=A_g Sigma_{g,2}^{1.5}$; a "Constant
molecular law", Sigma_sfr = A_H2 Sigma_{H2,2}; the "Turbulence-regulated laws"
of Krumholz & McKee (KM) and Krumholz, McKee & Tumlinson (KMT), a "Gas-Omega
law", Sigma_sfr = B_Omega Sigma_g Omega; and a shear-driven "GMC collisions
law", Sigma_sfr = B_CC Sigma_g Omega (1 - 0.7beta), where beta is d ln v_circ /
d ln r. We find the constant molecular law, KMT turbulence law and GMC
collision law are the most accurate, with an rms error of a factor of 1.5 if
the normalization constants are allowed to vary between galaxies. Of these
three laws, the GMC collision law does not require a change in physics to
account for the full range of star formation activity seen from normal galaxies
to circumnuclear starbursts. A single global GMC collision law with
B_CC=8.0x10^{-3}, i.e. a gas consumption time of 20 orbital times for beta=0,
yields an rms error of a factor of 1.8.Comment: 6 pages, including 2 figures, matches version published in ApJ
Conceptualizing smart service systems.
Recent years have seen the emergence of physical products that are digitally networked with other products and with information systems to enable complex business scenarios in manufacturing, mobility, or healthcare. These "smart products", which enable the co-creation of "smart service" that is based on monitoring, optimization, remote control, and autonomous adaptation of products, profoundly transform service systems into what we call "smart service systems". In a multi-method study that includes conceptual research and qualitative data from in-depth interviews, we conceptualize "smart service" and "smart service systems" based on using smart products as boundary objects that integrate service consumers' and service providers' resources and activities. Smart products allow both actors to retrieve and to analyze aggregated field evidence and to adapt service systems based on contextual data. We discuss the implications that the introduction of smart service systems have for foundational concepts of service science and conclude that smart service systems are characterized by technology-mediated, continuous, and routinized interactions
On the stability of Cosmic String Y-junctions
We study the evolution of non-periodic cosmic string loops containing
Y-junctions, such as may form during the evolution of a network of (p,q) cosmic
superstrings. We set up and solve the Nambu-Goto equations of motion for a loop
with junctions, focusing attention on a specific static and planar initial loop
configuration. After a given time, the junctions collide and the Nambu-Goto
description breaks down. We also study the same loop configuration in a
U(1)xU(1) field theory model that allows composite vortices with corresponding
Y-junctions. We show that the field theory and Nambu-Goto evolution are
remarkably similar until the collision time. However, in the field theory
evolution a new phenomenon occurs: the composite vortices can unzip, producing
in the process new Y-junctions, whose separation may grow significantly,
destabilizing the configuration. In particular, an initial loop with two
Y-junctions may evolve to a configuration with six Y-junctions (all distant
from each other). Setting up this new configuration as an initial condition for
Nambu Goto strings, we solve for its evolution and establish conditions under
which it is stable to the decay mode seen in the field theory case. Remarkably,
the condition closely matches that seen in the field theory simulations, and is
expressed in terms of simple parameters of the Nambu-Goto system. This implies
that there is an easy way to understand the instability in terms of which
region of parameter space leads to stable or unstable unzippings.Comment: 16 pages, 11 figures, typos correcte
Conceptualizing smart service systems
Recent years have seen the emergence of physical products that are digitally networked with other products and with information systems to enable complex business scenarios in manufacturing, mobility, or healthcare. These “smart products”, which enable the co-creation of “smart service” that is based on monitoring, optimization, remote control, and autonomous adaptation of products, profoundly transform service systems into what we call “smart service systems”. In a multi-method study that includes conceptual research and qualitative data from in-depth interviews, we conceptualize “smart service” and “smart service systems” based on using smart products as boundary objects that integrate service consumers’ and service providers’ resources and activities. Smart products allow both actors to retrieve and to analyze aggregated field evidence and to adapt service systems based on contextual data. We discuss the implications that the introduction of smart service systems have for foundational concepts of service science and conclude that smart service systems are characterized by technology-mediated, continuous, and routinizedinteractions
A cluster of outflows in the Vulpecula Rift
We present CO, CO and CO (J=32) observations of a new
cluster of outflows in the Vulpecula Rift with HARP-B on the JCMT. The mass
associated with the outflows, measured using the CO HARP-B observations
and assuming a distance to the region of 2.3 kpc, is 129 \msol{}, while the
mass associated with the dense gas from CO observations is 458 \msol{}
and the associated sub-millimeter core has a mass of 327 112 \msol{}
independently determined from Bolocam 1.1mm data. The outflow-to-core mass
ratio is therefore 0.4, making this region one of the most efficient
observed thus far with more than an order of magnitude more mass in the outflow
than would be expected based on previous results. The kinetic energy associated
with the flows, 94 ergs, is enough to drive the turbulence in
the local clump, and potentially unbind the local region altogether. The
detection of SiO (J=87) emission toward the outflows indicates that the flow
is still active, and not simply a fossil flow. We also model the SEDs of the
four YSOs associated with the molecular material, finding them all to be of mid
to early B spectral type. The energetic nature of the outflows and significant
reservoir of cold dust detected in the sub-mm suggest that these intermediate
mass YSOs will continue to accrete and become massive, rather than reach the
main sequence at their current mass.Comment: 11 pages, 8 figures and 3 tables. Accepted to MNRAS. A
higher-resolution version of figure 1 will be included in the published
version and is available from the authors upon request. Updated with red and
blue wings swapped to match doppler shif
Unleashing Digital Process Innovation with Process Mining: Designing a Training Concept with Action Design Research
Process mining (PM) is an emerging trend across many industries. To exploit its potential of increased transparency and organizational efficiency, PM needs to be implemented successfully. Due to its specific characteristics, knowledge on the implementation of other information systems cannot be transferred seamlessly. Applying an action design research (ADR) approach in a mixed team with the PM provider Celonis, we develop a training solution to facilitate PM implementation from a third-party implementation partner’s perspective. Therefore, we first formulate the problem by investigating challenges in the implementation process. Next, we derive a training concept as an artifact, using the theoretical foundation of IT implementation models. We evaluate the artifact, reflect on, and formalize the learning. The paper contributes to the PM knowledge base by identifying 38 implementation challenges like quantifying the value of PM and transferring those insights into practice by developing a prototype solution
BLAST: The Mass Function, Lifetimes, and Properties of Intermediate Mass Cores from a 50 Square Degree Submillimeter Galactic Survey in Vela (l = ~265)
We present first results from an unbiased 50 deg^2 submillimeter Galactic
survey at 250, 350, and 500 micron from the 2006 flight of the Balloon-borne
Large Aperture Submillimeter Telescope (BLAST). The map has resolution ranging
from 36 arcsec to 60 arcsec in the three submillimeter bands spanning the
thermal emission peak of cold starless cores. We determine the temperature,
luminosity, and mass of more than one thousand compact sources in a range of
evolutionary stages and an unbiased statistical characterization of the
population. From comparison with C^(18)O data, we find the dust opacity per gas
mass, kappa r = 0.16 cm^2 g^(-1) at 250 micron, for cold clumps. We find that
2% of the mass of the molecular gas over this diverse region is in cores colder
than 14 K, and that the mass function for these cold cores is consistent with a
power law with index alpha = -3.22 +/- 0.14 over the mass range 14 M_sun < M <
80 M_sun. Additionally, we infer a mass-dependent cold core lifetime of t_c(M)
= 4E6 (M/20 M_sun)^(-0.9) years - longer than what has been found in previous
surveys of either low or high mass cores, and significantly longer than free
fall or likely turbulent decay times. This implies some form of non-thermal
support for cold cores during this early stage of star formation.Comment: Accepted for publication in the Astrophysical Journal. Maps available
at http://blastexperiment.info
Star Formation in Disk Galaxies. I. Formation and Evolution of Giant Molecular Clouds via Gravitational Instability and Cloud Collisions
We investigate the formation and evolution of giant molecular clouds (GMCs)
in a Milky-Way-like disk galaxy with a flat rotation curve. We perform a series
of 3D adaptive mesh refinement (AMR) numerical simulations that follow both the
global evolution on scales of ~20kpc and resolve down to scales ~<10pc with a
multiphase atomic interstellar medium (ISM). In this first study, we omit star
formation and feedback, and focus on the processes of gravitational instability
and cloud collisions and interactions. We define clouds as regions with
n_H>=100cm^-3 and track the evolution of individual clouds as they orbit
through the galaxy from their birth to their eventual destruction via merger or
via destructive collision with another cloud. After ~140Myr a large fraction of
the gas in the disk has fragmented into clouds with masses ~10^6 Msun and a
mass spectrum similar to that of Galactic GMCs. The disk settles into a quasi
steady state in which gravitational scattering of clouds keeps the disk near
the threshold of global gravitational instability. The cloud collision time is
found to be a small fraction, ~1/5, of the orbital time, and this is an
efficient mechanism to inject turbulence into the clouds. This helps to keep
clouds only moderately gravitationally bound, with virial parameters of order
unity. Many other observed GMC properties, such as mass surface density,
angular momentum, velocity dispersion, and vertical distribution, can be
accounted for in this simple model with no stellar feedback.Comment: 21 pages ApJ format, including 16 figures, accepted to Ap
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