1,872 research outputs found
Ask questions, get sales : close the deak and create long-term relationships / Stephan Schiffman.
No full textIncludes index.v, 168 pages ;In Ask Questions, Get Sales, the author and sales guru Stephan Schiffman helps readers boost their careers to the gold-medal level by teaching them how to strengthen their questioning skills during the sales process. The premise is simple yet effective: In order to be successful, salespeople need to change their mindset from "need-orientated" to "do-orientated". The message of the book centers around six core "do" questions: What do you do? How do you do it? When and where do you do it? Why do you do it that way? Who do you do it with? How can we help you do it better? With this indispensable guide in their briefcase, salespeople will have information at the ready to score big sales over the short term and the long term
Unemployment Benefits and Unemployment Rates of Low-Skilled and Elder Workers in West Germany: A Search Equilibrium Approach
No full textApproach Author & abstract Download 16 References 1 Citations Related works & more Corrections Author Listed: Launov, Andrey ([email protected]) (University of Kent) Wolff, Joachim ([email protected]) (Institute for Employment Research (IAB), Nuremberg) Klasen, Stephan ([email protected]) (University of Göttingen) Registered: Stephan Klasen Abstract In this paper we investigate whether the extension of the entitlement to unemployment benefits in the mid 80s can explain the increase in the unemployment rates of unskilled and elder workers in western Germany. To answer this question we estimate a version of the Burdett-Mortensen search equilibrium model and analyze how workers’ search behaviour responded to these reforms. We try both nonparametric and fully-parametric estimation methods and identify the cases in which the nonparametric approach cannot be applied. We find that the entitlement reforms are largely responsible for the increase of unemployment among unskilled workers
Unemployment Benefits and Unemployment Rates of Low-Skilled and Elder Workers in West Germany: A Search Equilibrium Approach
No full textApproach Author & abstract Download 16 References 1 Citations Related works & more Corrections Author Listed: Launov, Andrey ([email protected]) (University of Kent) Wolff, Joachim ([email protected]) (Institute for Employment Research (IAB), Nuremberg) Klasen, Stephan ([email protected]) (University of Göttingen) Registered: Stephan Klasen Abstract In this paper we investigate whether the extension of the entitlement to unemployment benefits in the mid 80s can explain the increase in the unemployment rates of unskilled and elder workers in western Germany. To answer this question we estimate a version of the Burdett-Mortensen search equilibrium model and analyze how workers’ search behaviour responded to these reforms. We try both nonparametric and fully-parametric estimation methods and identify the cases in which the nonparametric approach cannot be applied. We find that the entitlement reforms are largely responsible for the increase of unemployment among unskilled workers
Measuring Vulnerability to Poverty Using Long-Term Panel Data
No full textMeasuring Vulnerability to Poverty Using Long-Term Panel Data Author & abstract Download & other version 16 References 4 Citations Related works & more Corrections Author Listed: Katja Landau (Georg-August-University Göttingen) Stephan Klasen (Georg-August-University Göttingen) Walter Zucchini (Georg-August-University Göttingen) Registered: Stephan Klasen Abstract We investigate the accuracy of ex ante assessments of vulnerability to income poverty using cross-sectional data and panel data. We use long-term panel data from Germany and apply di fferent regression models, based on household covariates and previous-year equivalence income, to classify a household as vulnerable or not. Predictive performance is assessed using the Receiver Operating Characteristics (ROC), which takes account of false positive as well as true positive rates. Estimates based on cross-sectional data are much less accurate than those based on panel data, but for Germany, the accuracy of vulnerability predictions is limited even when panel data are used. In part this low accuracy is due to low poverty incidence and high mobility in and out of poverty
Measuring Vulnerability to Poverty Using Long-Term Panel Data
No full textMeasuring Vulnerability to Poverty Using Long-Term Panel Data Author & abstract Download & other version 16 References 4 Citations Related works & more Corrections Author Listed: Katja Landau (Georg-August-University Göttingen) Stephan Klasen (Georg-August-University Göttingen) Walter Zucchini (Georg-August-University Göttingen) Registered: Stephan Klasen Abstract We investigate the accuracy of ex ante assessments of vulnerability to income poverty using cross-sectional data and panel data. We use long-term panel data from Germany and apply di fferent regression models, based on household covariates and previous-year equivalence income, to classify a household as vulnerable or not. Predictive performance is assessed using the Receiver Operating Characteristics (ROC), which takes account of false positive as well as true positive rates. Estimates based on cross-sectional data are much less accurate than those based on panel data, but for Germany, the accuracy of vulnerability predictions is limited even when panel data are used. In part this low accuracy is due to low poverty incidence and high mobility in and out of poverty
Evaluation of in-store processes related to returnable packaging services offered in grocery stores - the store management perspective
No full textAuthor Stephan LehnerMasterarbeit Universität Linz 202
Evaluation of in-store processes related to returnable packaging services offered in grocery stores - the store management perspective
No full textAuthor Stephan LehnerMasterarbeit Universität Linz 202
Ultraschnelle kohärente Abbildung von Nanopartikeln mit Hilfe von Röntgen- Laser Strahlung
No full textAbstract Zusammenfassung Publications Introduction Currently used imaging
techniques Towards a new method Free-electron lasers Serial coherent
diffractive imaging Sorting diffraction patterns The orientation problem
Motivation and outline Part I Background 1 The theory of coherent X-ray
diffractive imaging 1.1 Lensless imaging: the phase problem 1.1.1 Phase
retrieval 1.1.2 Iterative phase retrieval algorithms 1.2 The orientation
problem 1.3 Resolution and the number of required diffraction snapshots 2
Digital image analysis and pattern recognition 2.1 Classification 2.2 Feature
extraction 2.2.1 Intensity variations 2.2.2 Rotation symmetry 2.2.3
"Eigenpatterns" 2.3 Supervised classification 2.3.1 Partitioning the feature
space 2.3.2 Random forest classifier Part II Results 3 Geodesic orientation
recovery 3.1 Establishing and interpreting similarities among diffraction
patterns 43 3.2 Identifying in-plane and out-of-plane rotations and combining
them to span the orientation space 3.3 gipral - an orientation recovery
algorithm in ten steps 3.4 Computational complexity 3.5 Generalization to
symmetric objects 4 On-line analysis 4.1 On-line hit rate estimation 4.2 On-
line size estimation 4.3 On-line feedback on sample concentration 4.4 CASS - a
framework for on-line analysis 5 Application 5.1 nanorice - an ellipsoidal
iron oxide nanoparticle 5.1.1 Data acquisition 5.1.2 Classification results
5.1.3 Orientation recovery results 5.1.4 Phase retrieval 5.1.5 Data
inhomogeneity 5.1.6 Using a simple geometric consideration as a control 5.2
Preliminary application to virus diffraction data 5.2.1 Samples 5.2.2 Results
- aerosol injection 5.2.3 Results - liquid jet injection x Table of Contents 6
Discussion 6.1 Comparison to other orientation recovery approaches 6.2 Towards
the imaging of biological samples 6.3 Room for improvements / outlook 6.3.1
Technical improvements 6.3.2 direct measurement and manipulation of
orientations 6.4 Conclusions Appendix A Existing approaches to the orientation
problem A.1 Correlation A.2 Common arc A.3 Bayesian methods A.4 Diffusion map
/ graph theory Appendix B Implementation B.1 Hardware optimization B.2
Parallelization B.2.1 Shared memory parallelization B.2.2 Distributed memory
parallellization B.3 Class hierarchies Appendix C Mathematical Tools C.1
Rodrigues Frank parametrization C.2 Object symmetries in Rodrigues-Frank space
C.3 extending geodesics C.4 Projections and mirror symmetry C.5
Orthogonalizing in-plane and out-of-plane rotations C.6 Discontinued:
neighborhood preserving embedding Appendix D Publications Acknowledgments
Index ReferencesCoherent diffractive imaging with X-ray free-electron lasers (X-FEL) promises
high-resolution structure determination of single microscopic particles
without the need for crystallization. The diffraction signal of small samples
can be very weak, a difficulty that can not be countered by merely increasing
the number of photons because the sample would be damaged by a high absorbed
radiation dose. Traditional X-ray crystallography avoids this problem by
bringing many sample particles into a periodic arrangement, which amplifies
the individual signals while distributing the absorbed dose. Depending on the
sample, however, crystallization can be very difficult or even impossible.
This thesis presents algorithms for a new imaging approach using X-FEL
radiation that works with single, non-crystalline sample particles. X-FELs can
deliver X-rays with a peak brilliance many orders of magnitude higher than
conventional X-ray sources, compensating for their weak interaction cross
sections. At the same time, FELs can produce ultra-short pulses down to a few
femtoseconds. In this way it is possible to perform ultra-fast imaging,
essentially “freezing” the atomic positions in time and terminating the
imaging process before the sample is destroyed by the absorbed radiation. This
thesis primarily focuses on the three-dimensional reconstruction of single
(and not necessarily crystalline) particles using coherent diffractive imaging
at X-FELs: in order to extract three-dimensional information from scattering
data, two-dimensional diffraction patterns from many different viewing angles
must be combined. Therefore, the diffraction signal of many identical sample
copies in random orientations is measured. The main result of this work is a
globally optimal algorithm that can recover the sample orientations solely
based on the diffraction signal, enabling three-dimensional imaging for
arbitrary samples. The problem of finding three-dimensional orientations is
reduced to one-dimensional sub-problems by arranging diffraction patterns in
geodesic similarity sequences. Relations between the one-dimensional sub-
problems are established by identifying rotations about the X-ray axis and
one-dimensional solutions are combined into a three-dimensional orientation
recovery. The global optimization approach ensures that information is
extracted from the whole diffraction dataset, not only individual diffraction
patterns. Therefore this method can cope with diffraction data sets consisting
of individual diffraction patterns with weak signals. The geodesic approach
can handle datasets from inhomogeneous samples as well as samples with
symmetries. A successful application to experimental X-FEL data is shown,
resulting in the first three-dimensional reconstruction of a nanoparticle
using X-FEL coherent diffractive imaging.Kohärente Abbildung mit Röntgenlasern (X-ray free-electron lasers, X-FEL)
ermöglicht die Strukturbestimmung von einzelnen mikroskopischen Teilchen mit
hoher Auflösung, ohne dass ihre Kristallisation notwendig ist. Das gestreute
Signal von kleinen Proben kann jedoch sehr schwach sein. Diese Schwierigkeit
kann nicht einfach durch mehr einfallende Photonen umgangen werden, da die
Probe bei der Absorption einer hohen Strahlendosis Schaden nimmt. Herkömmliche
Kristallographie vermeidet dieses Problem durch das periodische Anordnen
vieler Probenteilchen, wodurch das Signal verstärkt und die Strahlendosis
verteilt wird. Je nach Probe kann die Kristallisation jedoch sehr aufwändig
oder gar unmöglich sein. Diese Arbeit behandelt Algorithmen für ein neues
bildgebendes Verfahren mit X-FEL Strahlung, das ohne Kristallisation auskommt.
Mit X-FELs können Röntgenstrahlen mit sehr viel höherer Spitzenbrillanz
erzeugt werden als mit herkömmlichen Röntgenquellen; somit können die
schwachen Wechselwirkungsquerschnitte von Röntgenphotonen mit Materie
kompensiert werden. Gleichzeitig können diese Röntgenstrahlen sehr kurz
gepulst werden, bis hin zu wenigen Femtosekunden. Dadurch kann eine Bildgebung
erreicht werden, die so schnell ist, dass die Atompositionen zeitlich
„eingefroren“ werden und ein Abbild der Probe erzeugt wird, bevor diese durch
die absorbierte Strahlung zerstört wird. Das Hauptaugenmerk dieser Arbeit
liegt auf der dreidimensionalen Rekonstruktion: Um dreidimensionale
Information aus Streudaten zu gewinnen ist es erforderlich viele
zweidimensionale Streubilder aus verschiedenen Blickwinkeln zusammenzufassen.
Dazu werden Streubilder von vielen identischen Kopien der Probe sequentiell
gesammelt, wobei jede Probenkopie eine zufällige Orientierung hat. Das
wichtigste Ergebnis dieser Arbeit ist ein global optimaler Algorithmus, der
die Orientierungen allein mit Hilfe der Streubilder rekonstruiert, wodurch
eine dreidimensionale Bildgebung für beliebige Proben möglich wird. Dazu wird
das Problem dreidimensionale Orientierungen zu rekonstruieren in
eindimensionale Teilprobleme unterteilt, indem Streubilder aufgrund ihrer
Ähnlichkeit in geodätische Bildfolgen angeordnet werden. Die eindimensionalen
Teilprobleme werden dann miteinander in Bezug gebracht, indem gemeinsame
Drehungen um die Röntgenachse identifiziert werden. Somit können
eindimensionale Lösungen in eine dreidimensionale Rekonstruktion der
Orientierungen kombiniert werden. Die globale Optimierung stellt dabei sicher,
dass die Information des gesamten Datensatz genutzt wird, anstatt nur einzelne
Streubilder zu berücksichtigen. Aus diesem Grund kann diese Methode auch bei
Datensätzen eingesetzt werden, bei denen einzelne Streubilder nur ein
schwaches Signal erhalten. Die auf Geodäten beruhende Methode kann sowohl
Datensätze von inhomogenen Proben bewältigen, als auch mit Objektsymmetrien
umgehen. In dieser Arbeit wird eine erfolgreiche Anwendung auf experimentelle
X-FEL Daten gezeigt, die die erste dreidimensionalen Rekonstruktion eines
Nanopartikels mit Hilfe von kohärenten Abbildungen mit X-FELs ermöglichte
Ultrafast coherent diffractive imaging of nanoparticles using X-ray free electron laser radiation
No full textHybrid simulation of wake vortices of landing aircraft in a turbulent environment
No full textWake-vortex evolution during landing of a long range aircraft is investigated in a turbulent environment. The simulations cover final approach, touchdown on the tarmac, and the evolution of the wake after touchdown. An ambient turbulent crosswind and headwind field is generated in a pre-simulation. The wake is initialized using a RANS-LES coupling approach. The further development of the vortical wake is investigated by large-eddy simulation until final decay. Strong three-dimensional deformations appearing after touchdown and linkings with the ground are studied. The downwind vortex is strongly advected with crosswind and decays quickly. The interaction of plate line disturbances and end effects in a turbulent environment leads to irregular decay pattern
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