59 research outputs found
On the Relationships between Decision Management and Performance Measurement
Decision management is of utmost importance for the achievement of strategic and operational goals in any organisational context. Therefore, decisions should be considered as first-class citizens that need to be modelled, analysed, monitored to track their performance, and redesigned if necessary. Up to now, existing literature that studies decisions in the context of business processes has focused on the analysis of the definition of decisions themselves, in terms of accuracy, certainty, consistency, covering and correctness. However, to the best of our knowledge, no prior work exists that analyses the relationship between decisions and performance measurement. This paper identifies and analyses this relationship from three different perspectives, namely: the impact of decisions on process performance, the performance measurement of decisions, and the use of performance indicators in the definition of decisions. Furthermore, we also introduce solutions for the representation of these relationships based, amongst others, on the DMN standard.Ministerio de Economía y Competitividad BELI (TIN2015-70560-R)Junta de Andalucía P12-TIC-1867Junta de Andalucía P10-TIC-590
A new bond fluctuation method for a polymer undergoing gel electrophoresis
We present a new computational methodology for the investigation of gel
electrophoresis of polyelectrolytes. We have developed the method initially to
incorporate sliding motion of tight parts of a polymer pulled by an electric
field into the bond fluctuation method (BFM). Such motion due to tensile force
over distances much larger than the persistent length is realized by non-local
movement of a slack monomer at an either end of the tight part. The latter
movement is introduced stochastically. This new BFM overcomes the well-known
difficulty in the conventional BFM that polymers are trapped by gel fibers in
relatively large fields. At the same time it also reproduces properly
equilibrium properties of a polymer in a vanishing filed limit. The new BFM
thus turns out an efficient computational method to study gel electrophoresis
in a wide range of the electric field strength.Comment: 15 pages, 11 figure
Phase Transitions of Single Semi-stiff Polymer Chains
We study numerically a lattice model of semiflexible homopolymers with
nearest neighbor attraction and energetic preference for straight joints
between bonded monomers. For this we use a new algorithm, the "Pruned-Enriched
Rosenbluth Method" (PERM). It is very efficient both for relatively open
configurations at high temperatures and for compact and frozen-in low-T states.
This allows us to study in detail the phase diagram as a function of
nn-attraction epsilon and stiffness x. It shows a theta-collapse line with a
transition from open coils to molten compact globules (large epsilon) and a
freezing transition toward a state with orientational global order (large
stiffness x). Qualitatively this is similar to a recently studied mean field
theory (Doniach et al. (1996), J. Chem. Phys. 105, 1601), but there are
important differences. In contrast to the mean field theory, the
theta-temperature increases with stiffness x. The freezing temperature
increases even faster, and reaches the theta-line at a finite value of x. For
even stiffer chains, the freezing transition takes place directly without the
formation of an intermediate globule state. Although being in contrast with
mean filed theory, the latter has been conjectured already by Doniach et al. on
the basis of low statistics Monte Carlo simulations. Finally, we discuss the
relevance of the present model as a very crude model for protein folding.Comment: 11 pages, Latex, 8 figure
Polydisperse star polymer solutions
We analyze the effect of polydispersity in the arm number on the effective
interactions, structural correlations and the phase behavior of star polymers
in a good solvent. The effective interaction potential between two star
polymers with different arm numbers is derived using scaling theory. The
resulting expression is tested against monomer-resolved molecular dynamics
simulations. We find that the theoretical pair potential is in agreement with
the simulation data in a much wider polydispersity range than other proposed
potentials. We then use this pair potential as an input in a many-body theory
to investigate polydispersity effects on the structural correlations and the
phase diagram of dense star polymer solutions. In particular we find that a
polydispersity of 10%, which is typical in experimental samples, does not
significantly alter previous findings for the phase diagram of monodisperse
solutions.Comment: 14 pages, 7 figure
A New Monte Carlo Algorithm for Protein Folding
We demonstrate that the recently proposed pruned-enriched Rosenbluth method
(P. Grassberger, Phys. Rev. E 56 (1997) 3682) leads to extremely efficient
algorithms for the folding of simple model proteins. We test them on several
models for lattice heteropolymers, and compare to published Monte Carlo
studies. In all cases our algorithms are faster than all previous ones, and in
several cases we find new minimal energy states. In addition to ground states,
our algorithms give estimates for the partition sum at finite temperatures.Comment: 4 pages, Latex incl. 3 eps-figs., submitted to Phys. Rev. Lett.,
revised version with changes in the tex
Scaling of Star Polymers with one to 80 Arms
We present large statistics simulations of 3-dimensional star polymers with
up to arms, and with up to 4000 monomers per arm for small values of
. They were done for the Domb-Joyce model on the simple cubic lattice. This
is a model with soft core exclusion which allows multiple occupancy of sites
but punishes each same-site pair of monomers with a Boltzmann factor . We
use this to allow all arms to be attached at the central site, and we use the
`magic' value to minimize corrections to scaling. The simulations are
made with a very efficient chain growth algorithm with resampling, PERM,
modified to allow simultaneous growth of all arms. This allows us to measure
not only the swelling (as observed from the center-to-end distances), but also
the partition sum. The latter gives very precise estimates of the critical
exponents . For completeness we made also extensive simulations of
linear (unbranched) polymers which give the best estimates for the exponent
.Comment: 7 pages, 7 figure
A review of Monte Carlo simulations of polymers with PERM
In this review, we describe applications of the pruned-enriched Rosenbluth
method (PERM), a sequential Monte Carlo algorithm with resampling, to various
problems in polymer physics. PERM produces samples according to any given
prescribed weight distribution, by growing configurations step by step with
controlled bias, and correcting "bad" configurations by "population control".
The latter is implemented, in contrast to other population based algorithms
like e.g. genetic algorithms, by depth-first recursion which avoids storing all
members of the population at the same time in computer memory. The problems we
discuss all concern single polymers (with one exception), but under various
conditions: Homopolymers in good solvents and at the point, semi-stiff
polymers, polymers in confining geometries, stretched polymers undergoing a
forced globule-linear transition, star polymers, bottle brushes, lattice
animals as a model for randomly branched polymers, DNA melting, and finally --
as the only system at low temperatures, lattice heteropolymers as simple models
for protein folding. PERM is for some of these problems the method of choice,
but it can also fail. We discuss how to recognize when a result is reliable,
and we discuss also some types of bias that can be crucial in guiding the
growth into the right directions.Comment: 29 pages, 26 figures, to be published in J. Stat. Phys. (2011
Theta-point behavior of diluted polymer solutions: Can one observe the universal logarithmic corrections predicted by field theory?
In recent large scale Monte-Carlo simulations of various models of
Theta-point polymers in three dimensions Grassberger and Hegger found
logarithmic corrections to mean field theory with amplitudes much larger than
the universal amplitudes of the leading logarithmic corrections calculated by
Duplantier in the framework of tricritical O(n) field theory. To resolve this
issue we calculate the universal subleading correction of field theory, which
turns out to be of the same order of magnitude as the leading correction for
all chain lengths available in present days simulations. Borel resummation of
the renormalization group flow equations also shows the presence of such large
corrections. This suggests that the published simulations did not reach the
asymptotic regime. To further support this view, we present results of
Monte-Carlo simulations on a Domb-Joyce like model of weakly interacting random
walks. Again the results cannot be explained by keeping only the leading
corrections, but are in fair accord with our full theoretical result. The
corrections found for the Domb-Joyce model are much smaller than those for
other models, which clearly shows that the effective corrections are not yet in
the asymptotic regime. All together our findings show that the existing
simulations of Theta-polymers are compatible with tricritical field theory
since the crossover to the asymptotic regime is very slow. Similar results were
found earlier for self avoiding walks at their upper critical dimension d=4.Comment: 15 pages,6 figure
Managing Decision Tasks and Events in Time-Aware Business Process Models
Time-aware business process models capture processes where temporal properties and constraints have to be suitably managed to achieve proper completion. Temporal aspects also constrain how decisions are made in processes: while some constraints hold only along certain paths, decision outcomes may be restricted to satisfy temporal constraints. In this paper, we present time-aware BPMN processes and discuss how to: (i) add temporal features to process elements, by considering also the impact of events on temporal constraint management; (ii) characterize decisions based on when they are made and used within a process; (iii) specify and use two novel kinds of decisions based on how their outcomes are managed; (iv) deal with intertwined temporal and decision aspects of time-aware BPMN processes to ensure proper execution
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