42 research outputs found
Efficient block designs for comparing dual with single treatments.
No full textExperiments in blocks having two treatment factors are considered in which a particular treatment must be excluded. The work is motivated by medical trials of two drugs in which a double placebo cannot be administered on ethical grounds. The contrasts of interest compare the effects of having both treatment factor at non-zero labelled levels with the effects of having only one treatment factor at a non-zero labelled level. For nx2 experiments, a class of designs containing highly efficient members is identified and a lower bound on the efficiencies of designs in this class is derived. Tables of efficient designs are provided
Efficient crossover designs in the presence of interactions between direct and carry-over treatment effects
No full textCrossover designs, or repeated measurements designs, are used for experiments in which t treatments are applied to each of n experimental units successively over p time periods. Such experiments are widely used in areas such as clinical trials, experimental psychology and agricultural field trials. In addition to the direct effect on the response of the treatment in the period of application, there is also the possible presence of a residual, or carry-over, effect of a treatment from one or more previous periods. We use a model in which the residual effect from a treatment depends upon the treatment applied in the succeeding period; that is, a model which includes interactions between the treatment direct and residual effects. We assume that residual effects do not persist further than one succeeding period.A particular class of strongly balanced repeated measurements designs with n=t2 units and which are uniform on the periods is examined. A lower bound for the A-efficiency of the designs for estimating the direct effects is derived and it is shown that such designs are highly efficient for any number of periods p=2,…,2
“The Goal is Human Rights as Women’s Rights”
No full textFrauen, die im Schatten der großen Männern standen, werden als eigenständige Persönlichkeiten im Buch von Gisela Notz reflektiert. Sie, die schon immer Geschichte machten, blieben allzu lange im Hintergrund. Die Historikerin und Sozialwissenschaftlerin Gisela Notz holt sie ans Licht und erteilt ihnen das Wort. Es ist ihr dabei gelungen, mit konkreten biographischen Geschichten der 26 Frauen ein wichtiges Basiswerk zu schaffen. Die Autorin setzt sich mit den Brüchen des Werdeganges dieser Frauen auseinander und berührt die Schwachstellen der sozialdemokratischen Frauenpolitik. Ein Buch, dass nicht nur jungen Frauen als eine gute Tischlektüre empfohlen werden kann, sondern auch erfahrenere Frauen mit den entscheidenden gesellschaftlichen Umständen bekannt macht und sie durch die persönlichen Begegnungen mit diesen Politikerinnen bereichert.Women who stood in the shadow of great men are reflected upon as independent personalities in this book by Gisela Notz. They, who had always made history, remained in the background for too long. The historian and social scientist Gisela Notz brings them to light and provides the opportunity for them to speak. She has hereby succeeded in creating an important foundational work with concrete biographical stories of 26 women. The author deals with the breaches in their biographies and touches upon the weaknesses of Social Democratic women’s politics. This book can not only be recommended to younger women, but can also familiarize experienced women with the decisive societal circumstances and enrich them with the personal acquaintances made with these female politicians
Customized Sequential Designs for Random Simulation Experiments: Kriging Metamodelling and Bootstrapping
No full textThis paper proposes a novel method to select an experimental design for interpolation in random simulation.(Though the paper focuses on Kriging, this method may also apply to other types of metamodels such as linear regression models.)Assuming that simulation requires much computer time, it is important to select a design with a small number of observations (or simulation runs).The proposed method is therefore sequential.Its novelty is that it accounts for the specific input/output behavior (or response function) of the particular simulation at hand; i.e., the method is customized or application-driven.A tool for this customization is bootstrapping, which enables the estimation of the variances of predictions for inputs not yet simulated.The new method is tested through the classic M/M/1 queueing simulation.For this simulation the novel design indeed gives better results than a Latin Hypercube Sampling (LHS) with a prefixed sample of the same size.simulation;statistical methods;bootstrap
Two-Dimensional Minimax Latin Hypercube Designs
No full textWe investigate minimax Latin hypercube designs in two dimensions for several distance measures.For the l-distance we are able to construct minimax Latin hypercube designs of n points, and to determine the minimal covering radius, for all n.For the l1-distance we have a lower bound for the covering radius, and a construction of minimax Latin hypercube designs for (infinitely) many values of n.We conjecture that the obtained lower bound is attained, except for a few small (known) values of n.For the l2-distance we have generated minimax solutions up to n = 27 by an exhaustive search method.The latter Latin hypercube designs will be included in the website www.spacefillingdesigns.nl.minimax;Latin hypercube designs;circle coverings
Secondary Qualitative Analysis of Interviews. A Method Used for Gaining Insight Into the Work/Life Balance of Middle Managers in Germany
No full textThis paper outlines a secondary analysis of interviews from an application-oriented perspective. We conducted secondary analysis in a project focusing on "work/life balance of managers". The original data came from a study that investigated "interest orientations of middle managers", in which the author was directly involved in. This paper describes the methodological steps as well as the benefits and limitations that were faced by the application of this approach.
URN: urn:nbn:de:0114-fqs050134
