165 research outputs found
A model-based approach to language integration
The interactions of several languages within a soft- ware system pose a number of problems. There is several anecdotal and empirical evidence supporting such concerns. This paper presents a solution to achieve proper language integration in the context of language workbenches and with limited effort. A simple example is presented to show how cross- language constraints can be addressed and the quality of the support attainable, which covers error-checking and refactoring. A research agenda is then presented, to support future work in the area of language integration, taking advantage of modern language workbenches features
Glauber dynamics of phase transitions: SU(3) lattice gauge theory
Motivated by questions about the QCD deconfining phase transition, we studied
in two previous papers Model A (Glauber) dynamics of 2D and 3D Potts models,
focusing on structure factor evolution under heating (heating in the gauge
theory notation, i.e., cooling of the spin systems). In the present paper we
set for 3D Potts models (Ising and 3-state) the scale of the dynamical effects
by comparing to equilibrium results at first and second order phase transition
temperatures, obtained by re-weighting from a multicanonical ensemble. Our
finding is that the dynamics entirely overwhelms the critical and non-critical
equilibrium effects.
In the second half of the paper we extend our results by investigating the
Glauber dynamics of pure SU(3) lattice gauge on
lattices directly under heating quenches from the confined into the deconfined
regime. The exponential growth factors of the initial response are calculated,
which give Debye screening mass estimates. The quench leads to competing vacuum
domains of distinct triality, which delay equilibration of pure gauge
theory forever, while their role in full QCD remains a subtle question. As in
spin systems we find for pure SU(3) gauge theory a dynamical growth of
structure factors, reaching maxima which scale approximately with the volume of
the system, before settling down to equilibrium. Their influence on various
observables is studied and different lattice sizes are simulated to illustrate
an approach to a finite volume continuum limit. Strong correlations are found
during the dynamical process, but not in the deconfined phase at equilibrium.Comment: 12 pages, 18 figure
The bioliq process for producing synthetic transportation fuels
Biofuels of the second generation can contribute significantly to the replacement
of the currently used fossil energy carriers for transportation fuel production.
The lignocellulosic biomass residues used do not compete with food and feed
production, but have to be collected from wide-spread areas for industrial largescale
use. The two-stage gasification concept bioliq offers a solution to this problem.
It aims at the conversion of low-grade residual biomass from agriculture
and forestry into synthetic fuels and chemicals. Central element of the bioliq
process development is the 2–5 MW pilot plant along the complete process
chain: fast pyrolysis for pretreatment of biomass to obtain an energy dense, liquid
intermediate fuel, high-pressure entrained flow gasification providing low
methane synthesis gas free of tar, hot synthesis gas cleaning to separate acid
gases, and contaminants as well as methanol/dimethyl ether and subsequent following
gasoline synthesis. After construction and commissioning of the individual
process steps with partners from industry, first production of synthetic fuel
was successfully achieved in 2014. In addition to pilot plant operation for technology
demonstration, a research and development network has been established
providing the scientific basis for optimization and further development of
the bioliq process as well as to explore new applications of the technologies and
products involved
Feasibility of simultaneous PET/MR imaging in the head and upper neck area
Objective: The aim of this pilot study was to test and demonstrate the feasibility of simultaneous positron emission tomography (PET) and magnetic resonance imaging (MRI) of the head and upper neck area using a new hybrid PET/MRI system. Methods: Eight patients with malignant head and neck tumours were included in the pilot study. Directly after routine PET/CT imaging with a whole-body system using the glucose derivative 2-[18F]fluoro-2deoxy-D-glucose (FDG) as a radiotracer additional measurements were performed with a prototype PET/MRI system for simultaneous PET and MR imaging. Physiological radiotracer uptake within regular anatomical structures as well as tumour uptake were evaluated visually and semiquantitatively (metabolic ratios) in relation to cerebellar uptake on the PET/MRI and PET/CT systems. Results: The MR datasets showed excellent image quality without any recognisable artefacts caused by the inserted PET system. PET images obtained with the PET/MRI system exhibited better detailed resolution and greater image contrast in comparison to those from the PET/CT system. An excellent agreement between metabolic ratios obtained with both PET systems was found: R = 0.99 for structures with physiological tracer uptake, R = 0.96 for tumours. Conclusion: Simultaneous PET/MRI of the head and upper neck area is feasible with the new hybrid PET/MRI prototyp
Preoperative Volume Determination for Pituitary Adenoma
The most common sellar lesion is the pituitary adenoma, and sellar tumors are
approximately 10-15% of all intracranial neoplasms. Manual slice-by-slice
segmentation takes quite some time that can be reduced by using the appropriate
algorithms. In this contribution, we present a segmentation method for
pituitary adenoma. The method is based on an algorithm that we have applied
recently to segmenting glioblastoma multiforme. A modification of this scheme
is used for adenoma segmentation that is much harder to perform, due to lack of
contrast-enhanced boundaries. In our experimental evaluation, neurosurgeons
performed manual slice-by-slice segmentation of ten magnetic resonance imaging
(MRI) cases. The segmentations were compared to the segmentation results of the
proposed method using the Dice Similarity Coefficient (DSC). The average DSC
for all datasets was 75.92% +/- 7.24%. A manual segmentation took about four
minutes and our algorithm required about one second.Comment: 7 pages, 6 figures, 1 table, 16 references in Proc. SPIE 7963,
Medical Imaging 2011: Computer-Aided Diagnosis, 79632T (9 March 2011). arXiv
admin note: text overlap with arXiv:1103.177
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