745 research outputs found
A new model based analysis method for regional economic development effects
It is the aim of this paper to provide a new method for the estimation and evaluation of long time ago implemented transport infrastructure and policy measures. This requires before and after data on a small spatial aggregation level. The main problem consists in the separation of the overall economic development, from the spatial impact of the implemented measures. Therefore, timeseries data of economic growth seem to be necessary, at least for some selected variables. However, longterm data series are rather difficult to find, and data uncertainties may lead to fluctuations in the estimated growth rates. In addition, it is an empirical fact that the spatial development of a region, even without any specific infrastructure investment, is not homogeneous. In order to take into account the usual data restrictions and uncertainties as well as the further requirements mentioned above, the spatial dependency and the growth effect will be modeled. It seems to be reasonable, that the rate of change of the regional growth factor depends on the kind of the infrastructure investment implemented, as well as on the 'distances' of the zone is under consideration to different appropriate junction points (e.g. stops of a train, exits to a motorway,...) to the infrastructure. Furthermore, it is reasonable to assume, that the impact of the implemented infrastructure exhibits a strong distance dependence. Of course, a specific investment may have different impacts on the considered socioeconomic indicators. The different spatial growth factors and the parameters describing the spatial impact of the infrastructure investment will be estimated via a nonlinear optimization procedure. The method is applied to the determination and separation of the economic development effects of a light rail system and of a motorway in the Stuttgart Region.
Static and Dynamic Critical Behavior of a Symmetrical Binary Fluid: A Computer Simulation
A symmetrical binary, A+B Lennard-Jones mixture is studied by a combination
of semi-grandcanonical Monte Carlo (SGMC) and Molecular Dynamics (MD) methods
near a liquid-liquid critical temperature . Choosing equal chemical
potentials for the two species, the SGMC switches identities () to generate well-equilibrated configurations of the system on
the coexistence curve for and at the critical concentration, ,
for . A finite-size scaling analysis of the concentration susceptibility
above and of the order parameter below is performed, varying the
number of particles from N=400 to 12800. The data are fully compatible with the
expected critical exponents of the three-dimensional Ising universality class.
The equilibrium configurations from the SGMC runs are used as initial states
for microcanonical MD runs, from which transport coefficients are extracted.
Self-diffusion coefficients are obtained from the Einstein relation, while the
interdiffusion coefficient and the shear viscosity are estimated from
Green-Kubo expressions. As expected, the self-diffusion constant does not
display a detectable critical anomaly. With appropriate finite-size scaling
analysis, we show that the simulation data for the shear viscosity and the
mutual diffusion constant are quite consistent both with the theoretically
predicted behavior, including the critical exponents and amplitudes, and with
the most accurate experimental evidence.Comment: 35 pages, 13 figure
Korrekturverfahren zur Berechnung der Einkommen über der Beitragsbemessungsgrenze
"Der durchschnittliche Bruttojahreslohn pro Beschäftigtem in einer Region liefert wertvolle Informationen über die regionalen Verdienstmöglichkeiten. Bedingt durch das Meldeverfahren an die Sozialversicherungsträger werden die Einkommen jedoch nicht mit ihrer vollen Höhe erfasst, sondern nur bis zur jeweils gültigen Beitragsbemessungsgrenze. Alle Einkommen über der Beitragsbemessungsgrenze werden abgeschnitten. Der in einer Region gemessene durchschnittliche Bruttojahreslohn pro Beschäftigtem aller Beschäftigungsverhältnisse liegt somit niedriger als der 'tatsächliche' Mittelwert. Um die realen Verdienstmöglichkeiten in den einzelnen Regionen dennoch möglichst exakt abzubilden, muss dieser durch das institutionelle Abschneideverfahren bedingte Fehler bereinigt werden. Dazu wird die Einkommensverteilung über der Beitragsbemessungsgrenze sowie die 'abgeschnittene' Bruttolohn- und Gehaltssumme hinzugeschätzt und damit der Mittelwert für jede Region einzeln korrigiert. Das Verfahren dieser Lohnkorrektur wird in dem Beitrag ausführlich beschrieben." (Autorenreferat, IAB-Doku)Einkommenshöhe, Bruttolohn, Sozialversicherung, Versicherungsbeitrag, Bemessungsgrundlage, Einkommensverteilung, regionale Verteilung, Fehler, sozialversicherungspflichtige Arbeitnehmer, Verteilungstheorie
Neuer Gebietszuschnitt der Arbeitsmarktregionen im Raum Berlin und Brandenburg : kritische Überprüfung der bisher gültigen Arbeitsmarktregionen und Vorschläge für einen Neuzuschnitt
"Im Rahmen eines Gutachtens zur Neuabgrenzung der Fördergebiete ab dem Jahr 2007 für die Gemeinschaftsaufgabe (GA) 'Verbesserung der regionalen Wirtschaftsstruktur' wurden der derzeit gültige Gebietszuschnitt der Arbeitsmarktregionen der Länder Berlin und Brandenburg in Kooperation mit dem Steinbeis-Transferzentrum Angewandte Systemanalyse (STASA), Stuttgart überprüft und Vorschläge für einen künftigen kreisscharfen Neuzuschnitt entwickelt. In dem Beitrag werden die angewandten graphentheoretische Methoden und Aggregationsverfahren über Pendlerverflechtungen sowie die Ergebnisse für einen kreisscharfen Gebietszuschnitt der Arbeitsmarktregionen der Länder Berlin und Brandenburg vorgestellt." (Autorenreferat, IAB-Doku)Gemeinschaftsaufgabe Regionale Wirtschaftsförderung, Fördergebiet, Arbeitsmarktregion, Berlin-Brandenburg, Bundesrepublik Deutschland
Electronic and Structural Properties of the Ge/GeO2 Interface through Hybrid Functionals
The performance of silicon based microelectronic circuits reaches the end of the roadmap. New material systems are required for further improvements in speed and power consumption. Germanium is a possible candidate to substitute silicon for microelectronic devices. Its hole mobility is the highest of all semiconductor materials. Together with its lower band gap it could be an ideal material for energy-saving devices. This thesis is dedicated to first principles studies of the Ge/GeO2 interface through hybrid density functional theory. The substoichiometric region of the interface is of special interest. A wide substoichiometric region is supported by total energy calculations of a set of crystalline model systems. An unexpected structure organization was found through molecular dynamics simulations of substoichiometric GeO. We found that a majority of germanium and oxygen atoms are threefold coordinated, forming valence alternation pairs (VAPs). A detailed energetic analysis located the VAPs in the low-oxygen region of the interface. VAPs show interesting properties : They are prone to charge trapping. The electron trapping level might explain the bad performance of n-type doped devices. Furthermore, VAPs might be at the origin of the difficulties of H passivation at the Ge/GeO2 interface. Since threefold Ge atoms are negatively charged and threefold O atoms are positively charged, VAPs give rise to dipoles. These dipoles may reduce the interface dipole created by the electronegativity difference in the Ge-3O bond. With this mechanism, we can explain the wide range of experimental valence band offsets (VBOs) with the occurrence of different density levels of VAPs at the Ge/GeO2 interface. This suggestion is further confirmed by the determination of the VBO and Ge 3d core-level shift for an atomistic model structure of the Ge/GeO2 interface. Both values are systematically lower than typical experimental values for the Ge/GeO2 interface. Taking the extra dipole into account, our calculated VBOs and XPS shifts are in excellent agreement with experimental values. These results confirm that the structural properties of the Ge/GeO2 interface deviate significantly from its Si counterpart
Excited bound states and their role in dark matter production
We explore the impact of highly excited bound states on the evolution of
number densities of new physics particles, specifically dark matter, in the
early Universe. Focusing on dipole transitions within perturbative, unbroken
gauge theories, we develop an efficient method for including around a million
bound state formation and bound-to-bound transition processes. This enables us
to examine partial-wave unitarity and accurately describe the freeze-out
dynamics down to very low temperatures. In the non-Abelian case, we find that
highly excited states can prevent the particles from freezing out, supporting a
continuous depletion in the regime consistent with perturbativity and
unitarity. We apply our formalism to a simplified dark matter model featuring a
colored and electrically charged -channel mediator. Our focus is on the
regime of superWIMP production which is commonly characterized by a mediator
freeze-out followed by its late decay into dark matter. In contrast, we find
that excited states render mediator depletion efficient all the way until its
decay, introducing a dependence of the dark matter density on the mediator
lifetime as a novel feature. The impact on the viable dark matter mass can
amount to an order of magnitude, relaxing constraints from Lyman-
observations.Comment: 21 pages + references, 10 figure
iGraph: Intelligent Enterprise Information Logistics
Engineers in the automotive domain are confronted with a huge load of information making it difficult for them to identify the information relevant for performing their tasks. Particularly challenging is the alignment of process information, such as office files, checklists, and guidelines with business processes. In previous work, we introduced the concept of process-oriented information logistics (POIL) enabling the intelligent delivery of process information along business processes. In this paper, we present iGraph, an application implementing POIL.
Specifically, iGraph demonstrates how engineers can be supported with relevant process information during the review of product requirements
Modification of emission properties of ZnO layers due to plasmonic near-field coupling to Ag nanoislands
A simple fabrication method of Ag nanoislands on ZnO films is presented.
Continuous wave and time-resolved photoluminescence and transmission are
employed to investigate modifications of visible and UV emissions of ZnO
brought about by coupling to localized surface plasmons residing on Ag
nanoislands. The size of the nanoislands, determining their absorption and
scattering efficiencies, is found to be an important factor governing plasmonic
modification of optical response of ZnO films. The presence of the Ag
nanoislands of appropriate dimensions causes a strong (threefold) increase in
emission intensity and up to 1.5 times faster recombination. The experimental
results are successfully described by model calculations within the Mie theory.Comment: 14 pages, 5 figure
Neuer Gebietszuschnitt der Arbeitsmarktregionen im Raum Berlin und Brandenburg: kritische Überprüfung der bisher gültigen Arbeitsmarktregionen und Vorschläge für einen Neuzuschnitt
"Im Rahmen eines Gutachtens zur Neuabgrenzung der Fördergebiete ab
dem Jahr 2007 für die Gemeinschaftsaufgabe (GA) „Verbesserung der regionalen
Wirtschaftsstruktur“ wurde der derzeit gültige Gebietszuschnitt
der Arbeitsmarktregionen der Länder Berlin und Brandenburg in Kooperation
mit dem Steinbeis-Transferzentrum Angewandte Systemanalyse
(STASA), Stuttgart überprüft und Vorschläge für einen künftigen kreisscharfen
Neuzuschnitt entwickelt. Im vorliegenden Beitrag werden die angewandten
graphentheoretische Methoden und Aggregationsverfahren
über Pendlerverflechtungen sowie die Ergebnisse für einen kreisscharfen
Gebietszuschnitt der Arbeitsmarktregionen der Länder Berlin und Brandenburg
vorgestellt." [Autorenreferat
Korrekturverfahren zur Berechnung der Einkommen über der Beitragsbemessungsgrenze
"Der durchschnittliche Bruttojahreslohn pro Beschäftigtem in einer Region
liefert wertvolle Informationen über die regionalen Verdienstmöglichkeiten.
Bedingt durch das Meldeverfahren an die Sozialversicherungsträger
werden die Einkommen jedoch nicht mit ihrer vollen Höhe erfasst, sondern
nur bis zur jeweils gültigen Beitragsbemessungsgrenze. Alle Einkommen
über der Beitragsbemessungsgrenze werden abgeschnitten. Der in einer
Region gemessene durchschnittliche Bruttojahreslohn pro Beschäftigtem
aller Beschäftigungsverhältnisse liegt somit niedriger als der „tatsächliche“
Mittelwert. Um die realen Verdienstmöglichkeiten in den einzelnen Regionen
dennoch möglichst exakt abzubilden, muss dieser durch das institutionelle
Abschneideverfahren bedingte Fehler bereinigt werden. Dazu wird
die Einkommensverteilung über der Beitragsbemessungsgrenze sowie die
„abgeschnittene“ Bruttolohn- und Gehaltssumme hinzugeschätzt und damit
der Mittelwert für jede Region einzeln korrigiert. Das Verfahren dieser
Lohnkorrektur wird in dem vorliegenden Beitrag ausführlich beschrieben." [Autorenreferat
- …