Mostrando recursos 1 - 16 de 16

  1. Comparing Structural Efficiency of Unbalanced Subsamples: A Resampling Adaptation of Data Envelopment Analysis

    Gstach, Dieter
    At a general level the question is adressed, how to compare structural efficiencies for subgroups in the framework of data envelopment analysis. If a multiproduct technology is employed in estimating the production possibility frontier and if the subgroups are distinguished by products, then specific problems arise. It is illustrated by Monte-Carlo techniques that there may be considerable bias in relative structural efficiencies due to unbalanced numbers of observations for different subgroups. A resampling procedure is shown to outperform the simple estimators from data envelopment analysis in such circumstances. The method proposed is applied to austrian farming data to derive conclusions about the relationship...

  2. Silicon Glenn; a technological Brigadoon? an analysis of the electronics and IT industries in Scotland

    Sutherland, Ewan
    Series: IIR-Discussion Papers

  3. Regional Networks of High-Technology Firms The Case of the Greater Boston Region

    Tödtling, Franz
    The creation and application of new technologies in the form of new products or new processes is increasingly becoming a collective effort in which firms, universities and research laboratories as well as public and other institutions at various spatial scales are engaged. Some of these "networks" are international or even global, such as strategic alliances and R&D joint ventures, which are undertaken to mobilize complementary assets and to provide distant market access. However, it is at the the local and regional level that the development of technology-based firms is most often stimulated. The example of the Greater Boston region shows...

  4. Zur Entwicklung des grenzüberschreitenden Warenverkehrs im Einzugsbereich der AMD-Wasserstraße und der Mengenpotentiale der Binnenschiffahrt.

    Fischer, Manfred M.; Rammer, Christian; Essletzbichler, Jürgen
    (no abstract available)

  5. Tschechisches und slowakisches Aktienrecht

    Dedic, Jan
    Mit Einführung des neuen tschechoslowakischen Handelsgesetzbuches wurde auch das Gesellschaftsrecht im allgemeinen und das Aktienrecht im besonderen auf eine neue Basis gestellt. Diese Arbeit bietet einen systematischen Überblick über dieses Rechtsgebiet und berücksichtigt die Novelle des HGB zum 1. 1. 1993. Das HGB bleibt auch nach der Teilung der CSFR in beiden neuen Republiken in kraft. (Autorenref.)

  6. Ausgewählte Fragen des neuen russischen Wirschaftsrechts

    Sadikov, Oleg Nikolaewitsch; Micheler, Eva Maria
    Der Übergang Rußlands zur Marktwirtschaft machte radikale Reformen der Rechtsordnung nötig, da die alten Gesetze die Ideen der Planwirtschaft umsetzten. Diese Reformen wurden in mehreren Schritten verwirklicht und sind noch nicht vollendet. In der ersten Phase wurden Gesetze prinzipieller Art erlassen. Dazu zählen unter anderem das Eigentumsgesetz vom 25. Dezember 1990, das Gesetz über Unternehmen und unternehmerische Tätigkeit vom 25. Dezember 1990 und das Gesetz über die Privatisierung staatlicher und munizipaler Unternehmen vom 3. Juli 1991 sowie zahlreiche Novellierungen der russischen Verfassung. Die genannten Gesetze wurden in der Auslandspresse bereits besprochen und teilweise übersetzt. Gegenstand dieser Arbeit werden daher einige...

  7. Discrimination Between Two Binary Data Models. Sequentially Designed Experiments.

    Müller, Werner; Ponce de Leon, Antonio C.
    In this paper we describe and illustrate a sequential approach for the problem of designing experiments to discriminate between binary data models as efficiently as possible. The models considered ought to belong to the class of binary response models which is conveniently regarded as a subclass of Generalized Linear Models. Further they may be either nested or non-nested, and theirlinear predictor structures must be given. We examine this problem for the case of two rival models. Optimal design theory is utilized so as to derive important properties of and relevant results with respect to optimal experimental designs. Two sequential methods...

  8. Behaviour on the Length Test for Medium Sample Sizes

    Dittrich, Regina; Reschenhofer, Erhard; Bomze, Immanuel
    In this note it is shown that even for relatively large sample sizes the asymptotic distribution of the smoothed length as derived in Reschenhofer and Bomre (1991) should not be used for the determination of critical values. Therefore extended tables of critical values for both the 1% and 5% levels of significance generated by simulation are presented. (author's abstract)

  9. Applied State Space Modelling of Non-Gaussian Time Series using Integration-based Kalman-filtering

    Frühwirth-Schnatter, Sylvia
    The main topic of the paper is on-line filtering for non-Gaussian dynamic (state space) models by approximate computation of the first two posterior moments using efficient numerical integration. Based on approximating the prior of the state vector by a normal density, we prove that the posterior moments of the state vector are related to the posterior moments of the linear predictor in a simple way. For the linear predictor Gauss-Hermite integration is carried out with automatic reparametrization based on an approximate posterior mode filter. We illustrate how further topics in applied state space modelling such as estimating hyperparameters, computing model...

  10. Bayesian Model Discrimination and Bayes Factors for Normal Linear State Space Models

    Frühwirth-Schnatter, Sylvia
    It is suggested to discriminate between different state space models for a given time series by means of a Bayesian approach which chooses the model that minimizes the expected loss. Practical implementation of this procedures requires a fully Bayesian analysis for both the state vector and the unknown hyperparameters which is carried out by Markov chain Monte Carlo methods. Application to some non-standard situations such as testing hypotheses on the boundary of the parameter space, discriminating non-nested models and discrimination of more than two models is discussed in detail. (author's abstract)

  11. Single and Twin-Heaps as Natural Data Structures for Percentile Point Simulation Algorithms

    Hatzinger, Reinhold; Panny, Wolfgang
    Sometimes percentile points cannot be determined analytically. In such cases one has to resort to Monte Carlo techniques. In order to provide reliable and accurate results it is usually necessary to generate rather large samples. Thus the proper organization of the relevant data is of crucial importance. In this paper we investigate the appropriateness of heap-based data structures for the percentile point estimation problem. Theoretical considerations and empirical results give evidence of the good performance of these structures regarding their time and space complexity. (author's abstract)

  12. Optimal Design of an Experiment in Economics

    Müller, Werner; Ponce de Leon, Antonio C.
    This paper deals with the application of optimal design principles in an experiment examining individual decision making under risk. It provides general principles on how to conduct experiments in a probit model estimation situation and illust rates the benefit of those techniques through equivalent number of observations. (author's abstract)

  13. A universal generator for discrete log-concave distributions

    Hörmann, Wolfgang
    We give an algorithm that can be used to sample from any discrete log-concave distribution (e.g. the binomial and hypergeometric distributions). It is based on rejection from a discrete dominating distribution that consists of parts of the geometric distribution. The algorithm is uniformly fast for all discrete log-concave distributions and not much slower than algorithms designed for a single distribution. (author's abstract)

  14. The quality of non-uniform random numbers

    Hörmann, Wolfgang
    The quality of non-uniform random numbers is not only influenced by the quality of the uniform generator that is used but also by the transformation method applied to the uniform random numbers. This differences in quality between ``exact" methods were almost entirely neglected in literature. So we compare the behaviour of four different transformation methods when combined with a linear congruential uniform generator (LCG). Heuristic considerations, the computation of two measures of approximation and a statistical test show that the inversion method performs best. Among the others rejection, when combined with a LCG with small multiplier, and ratio of uniforms...

  15. On the number of nodal domains of spherical harmonics

    Leydold, Josef
    It is well known that the n-th eigenfunction to one-dimensional Sturm-Liouville eigenvalue problems has exactly n-1 nodes, i.e. non-degenerate zeros. For higher dimensions, it is much more complicated to obtain general statements on the zeros of eigenfunctions. The author states a new conjecture on the number of nodal domains of spherical harmonics, i.e. of connected components of S^2 \ N(u) with the nodal set N(u) = (x in S^2 : u(x) = 0) of the eigenfunction u, and proves it for the first six eigenvalues. It is a sharp upper bound, thus improving known bounds as the Courant nodal domain...

  16. A note on the quality of random variates generated by the ratio of uniforms method

    Hörmann, Wolfgang
    The one-dimensional distribution of pseudo-random numbers generated by the ratio of uniforms methods using linear congruential generators (LCGs) as the source of uniform random numbers is investigated in this paper. Due to the two-dimensional lattice structure of LCGs there is always a comparable large gap without a point in the one-dimensional distribution of any ratio of uniforms method. Lower bounds for these probabilities only depending on the modulus and the Beyer quotient of the LCG are proved for the case that the Cauchy the normal or the exponential distribution are generated. These bounds justify the recommendation not to use the...

Aviso de cookies: Usamos cookies propias y de terceros para mejorar nuestros servicios, para análisis estadístico y para mostrarle publicidad. Si continua navegando consideramos que acepta su uso en los términos establecidos en la Política de cookies.