1.
Oskar Morgenstern als wirtschaftspolitischer Berater in den 1930er-Jahren - Klausinger, Hansjörg
The point of departure of this study is that in the 1930s Oskar Morgenstern, well-known as the co-founder of game theory, was preoccupied by his activities in Austrian economic policy, possibly even more so than with his project to revolutionize economic theory. The main questions to be examined in this regard are, first, to what extent Morgenstern?s advice did conform to the teachings of the Austrian school and, second, if he really exerted an influence on economic policy-making in Austria during this period. In order to answer this question the paper draws to a large part on unpublished sources from...
3.
Motive und Konsequenzen einer Familiennachfolge - Diwisch, Sandra D.; Weiss, Christoph R.
Familienunternehmen spielen im wirtschaftlichen und gesellschaftlichen Kontext eine zentrale Rolle. Ein unterscheidendes Charakteristikum des Familienunternehmens gegenüber anderen Unternehmen ist per Definition die Unternehmensnachfolge, da der Fortbestand eines Familienunternehmens als solches nur dann gesichert ist, wenn dieses an ein Familienmitglied übertragen wird. Die vorliegende Arbeit fasst die ökonomische Literatur zu den Motiven und Konsequenzen der Unternehmensnachfolge zusammen. Ausführlicher wird auf empirische Ergebnisse für Österreich eingegangen, wobei die Konsequenzen von Unternehmensnachfolgen für das Beschäftigungswachstum des betrachteten Unternehmens untersucht werden. Unter Anwendung des nichtparametrischen Propensity Score Matching Ansatzes wird ein positiver und signifikanter Zusammenhang zwischen einer realisierten Nachfolge und dem Beschäftigungswachstum gefunden, der...
4.
Einsatz und Auswahl von Managementunterstützungssystemen in österreichischen Großunternehmen - Meyer, David
Einsatz und Reifegrad von Business Intelligence (BI)-Systemen werden in Deutschland laufend untersucht. Diese Arbeit präsentiert die Ergebnisse einer sowohl auf Fragebögen wie auch Experteninterviews basierenden Umfrage bei österreichischen Großunternehmen hinsichtlich Einsatz und Auswahl von BI-Werkzeugen. Die Kernaussagen sind konsistent mit den vorherigen Studien: es liegt ein mittlerer Reifegrad der Systeme vor, wobei jedoch sektorale Unterschiede bestehen, und es zeigen sich durchgängig starke Integrationstendenzen bei der Gestaltung des BI-Portfolios. (Autorenref.)
5.
Einsatz und Auswahl von Managementunterstützungssystemen in österreichischen Großunternehmen - Meyer, David
Einsatz und Reifegrad von Business Intelligence (BI)-Systemen werden in Deutschland laufend untersucht. Diese Arbeit präsentiert die Ergebnisse einer sowohl auf Fragebögen wie auch Experteninterviews basierenden Umfrage bei österreichischen Großunternehmen hinsichtlich Einsatz und Auswahl von BI-Werkzeugen. Die Kernaussagen sind konsistent mit den vorherigen Studien: es liegt ein mittlerer Reifegrad der Systeme vor, wobei jedoch sektorale Unterschiede bestehen, und es zeigen sich durchgängig starke Integrationstendenzen bei der Gestaltung des BI-Portfolios. (Autorenref.)
6.
Universal Generators for Correlation Induction - Hörmann, Wolfgang; Derflinger, Gerhard
Compared with algorithms specialized for a single distribution universal (also called automatic or black-box) algorithms for continuous distributions were relatively seldom discussed. But they have important advantages for the user: One algorithm coded and tested only once can do the same or even more than a whole library of standard routines. It is only necessary to have a program available that can evaluate the density of the distribution up to a multiplicative factor. In this paper we show that transformed density rejection is well suited to construct universal algorithms suitable for correlation induction which is important for variance reduction in...
7.
A Universal Generator for Bivariate Log-Concave Distributions - Hörmann, Wolfgang
Different universal (also called automatic or black-box) methods have been suggested to sample from univariate log-concave distributions. The description of a universal generator for bivariate distributions has not been published up to now. The new algorithm for bivariate log-concave distributions is based on the method of transformed density rejection. In order to construct a hat function for a rejection algorithm the bivariate density is transformed by the logarithm into a concave function. Then it is possible to construct a dominating function by taking the minimum of several tangent planes which are by exponentiation transformed back into the original scale. The...
8.
A Faber-Krahn-type Inequality for Regular Trees - Leydold, Josef
In the last years some results for the Laplacian on manifolds have been shown to hold also for the graph Laplacian, e.g. Courant's nodal domain theorem or Cheeger's inequality. Friedman (Some geometric aspects of graphs and their eigenfunctions, Duke Math. J. 69 (3), pp. 487-525, 1993) described the idea of a ``graph with boundary". With this concept it is possible to formulate Dirichlet and Neumann eigenvalue problems. Friedman also conjectured another ``classical" result for manifolds, the Faber-Krahn theorem, for regular bounded trees with boundary. The Faber-Krahn theorem states that among all bounded domains $D \subset R^n$ with fixed volume, a...
9.
Rejection-Inversion to Generate Variates from Monotone Discrete Distributions - Hörmann, Wolfgang; Derflinger, Gerhard
For discrete distributions a variant of rejection from a continuous hat function is presented. The main advantage of the new method, called rejection-inversion, is that no extra uniform random number to decide between acceptance and rejection is required which means that the expected number of uniform variates required is halved. Using rejection-inversion and a squeeze, a simple universal method for a large class of monotone discrete distributions is developed. It can be used to generate variates from the tails of most standard discrete distributions. Rejection-inversion applied to the Zipf (or zeta) distribution results in algorithms that are short and simple...
10.
Semiparametric and Nonparametric Testing for Long Memory - Hauser, Michael A.
The finite sample properties of three semiparametric estimators, several versions of the modified rescaled range, MMR, and three versions of the GHURST estimator are investigated. Their power and size for testing for long memory under short-run effects, joint short and long-run effects, heteroscedasticity and t-distributions are given using Monte Carlo methods. The MMR with the Barlett window is generally robust with the disadvantage of a relatively small power. The trimmed Whittle likelihood has high power in general and is robust expect for large short-run effects. The tests are applied to chandes in exchange rate series (daily data) of 6 major...
11.
The Generation of Stationary Gaussian Time Series - Hauser, Michael A.; Hörmann, Wolfgang
Three different algorithms for the generation of stationary Gaussian time series with given autocorrelation function are presented in this paper. The algorithms have already been suggested in the literature but are not well known and have never been compared before. Interrelations between the different methods, advantages and disadvantages with respect to speed and memory requirements and the range of autocorrelation functions for which the different methods are stable are discussed. The time-complexity of the algorithms and the comparisons of their implementations show that the method twice using the Fourier transform is by far the most efficient if time series of...
12.
A Sweep-Plane Algorithm for Generating Random Tuples in Simple Polytopes - Leydold, Josef; Hörmann, Wolfgang
A sweep-plane algorithm by Lawrence for convex polytope computation is adapted to generate random tuples on simple polytopes. In our method an affine hyperplane is swept through the given polytope until a random fraction (sampled from a proper univariate distribution) of the volume of the polytope is covered. Then the intersection of the plane with the polytope is a simple polytope with smaller dimension. In the second part we apply this method to construct a black-box algorithm for log-concave and T-concave multivariate distributions by means of transformed density rejection. (author's abstract)
13.
An Automatic Generator for a Large Class of Unimodal Discrete Distributions - Hörmann, Wolfgang; Derflinger, Gerhard
The automatic Algorithm ARI developed in this paper can generate variates from a large class of unimodal discrete distributions. It is only necessary to know the mode of the distribution and to have a subprogram available that can evaluate the probabilities. In a set up step the algorithm constructs a table mountain shaped hat function. Then rejection inversion, a new variant of the rejection method for discrete distributions that needs only one uniform random number per iteration, is used to sample from the desired distribution. It is shown that the expeceted number of iterations is uniformly bounded for all T-concave...
14.
The Automatic Generation of One- and Multi-dimensional Distributions with Transformed Density Rejection - Leydold, Josef; Hörmann, Wolfgang
A rejection algorithm, called ``transformed density rejection", is presented. It uses a new method for constructing simple hat functions for a unimodal density $f$. It is based on the idea of transforming $f$ with a suitable transformation $T$ such that $T(f(x))$ is concave. The hat function is then constructed by taking the pointwise minimum of tangents which are transformed back to the original scale. The resulting algorithm works very well for a large class of distributions and is fast. The method is also extended to the two- and multidimensional case. (author's abstract)
15.
A Rejection Technique for Sampling from Log-Concave Multivariate Distributions - Leydold, Josef
Different universal methods (also called automatic or black-box methods) have been suggested to sample from univariate log-concave distributions. The description of a suitable universal generator for multivariate distributions in arbitrary dimensions has not been published up to now. The new algorithm is based on the method of transformed density rejection. To construct a hat function for the rejection algorithm the multivariate density is tranformed by a proper transformation T into a concave function (in the case of log-concave density T(x) = log(x).) Then it is possible to construct a dominating function by taking the minimum of several tangent hyperplanes which...
16.
Maximum Likelihood Estimators for ARMA and ARFIMA Models - Hauser, Michael
We analyze by simulation the properties of two time domain and two frequency domain estimators for low order autoregressive fractionally integrated moving average Gaussian models, ARFIMA (p,d,q). The estimators considered are the exact maximum likelihood for demeaned data, EML, the associated modified profile likelihood, MPL, and the Whittle estimator with, WLT, and without tapered data, WL. Length of the series is 100. The estimators are compared in terms of pile-up effect, mean square error, bias, and empirical confidence level. The tapered version of the Whittle likelihood turns out to be a reliable estimator for ARMA and ARFIMA models. Its small...
17.
Reasons for the U.S. growth period in the nineties: non-keynesian effects, asset wealth and productivity - Burger, Anton
This paper investigates several possible reasons for the exceptional period of growth in the nineties in the US.. These years can be characterised as a case of an expansionary fiscal consolidation as strong growth and structural surpluses were observed. Five different channels, the literature suggests for relationships between government spending and consumption are investigated. There are hints that the economy did not work in a Keynesian way but there is no proof of the existence of a Non-Keynesian effect. Expectational effects could not be separated empirically from asset wealth. Whereas standard consumption estimations failed, a model adding a factor containing...
18.
Minimal Cycle Bases of Outerplanar Graphs - Leydold, Josef; Stadler, Peter F.
2-connected outerplanar graphs have a unique minimal cycle basis with length 2|E|-|V|. They are the only Hamiltonian graphs with a cycle basis of this length. (author's abstract)
19.
The Geometry of Regular Trees with the Faber-Krahn Property - Leydold, Josef
In this paper we prove a Faber-Krahn-type inequality for regular trees and give a complete characterization of extremal trees. It extends a former result of the author. The main tools are rearrangements and perturbation of regular trees. (author's abstract)
20.
Higher-Dimensional Properties of Non-Uniform Pseudo-Random Variates - Leydold, Josef; Leeb, Hannes; Hörmann, Wolfgang
In this paper we present the results of a first empirical investigation on how the quality of non-uniform variates is influenced by the underlying uniform RNG and the transformation method used. We use well known standard RNGs and transformation methods to the normal distribution as examples. We find that except for transformed density rejection methods, which do not seem to introduce any additional defects, the quality of the underlying uniform RNG can be both increased and decreased by transformations to non-uniform distributions. (author's abstract)
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