Sektion Wissenssoziologie

Ohne Zusammenfassung unter Mithilfe von Jule Lorenzen, Sabine Petschke, Lisa-Marian Schmidt und René Tuma     

On Integer Programming Approaches for Morphological Template Decomposition Problems in Computer Vision

In morphological image processing and analysis, a template or structuringelement is applied to an image. Often savings in computation time and abetter fit to the given computer architecture can be achieved by using thetechnique of template decomposition. Researchers have written a multitude ofpapers on finding such decompositions for special classes of templates.Justifying recent integer programming approaches to the morphologicaltemplate decomposition problem in its general form, this paper proves theNP-completeness of this problem.     

Principal component and correspondence analysis of compositional data: some similarities

Principal component and correspondence analysis can both be used as exploratory methods for representing multivariate data in two dimensions. Circumstances under which the, possibly inappropriate, application of principal components to untransformed compositional data approximates to a correspondence analysis of the raw data are noted. Aitchison (1986) has proposed a method for the principal component analysis of compositional data involving transformation of the raw data. It is shown how this can be approximated by a correspondence analysis of appropriately transformed data. The latter approach may be preferable when there are zeroes in the data.     

Regularities and irregularities in a random 0,1 sequence

A few properties of the random 0,1 sequences are studied. These properties can be utilized to test the randomness of a 0,1 sequence produced by a computer (random generator). This test seems to be appropriate for discovering the periodicity (or the length of the period) of a pseudorandom sequence. A possible application of the presented results in regression analysis is also discussed.     

Return Migrations of African‐Americans to the South: Reclaiming a Land of Promise,Going Home,or Both?*

Abstract Using samples of census data from the University of Minnesota Population Center's “Integrated Public Use Microdata Series” (IPUMS), we describe trends in African‐American migration to the South across recent decades, and explore the applicability of the concept of “return migration” to various demographic patterns. Our findings suggest that the return movement contains multiple migration streams involving African‐Americans of higher socio‐economic status (compared with both origin and destination populations) moving to both urban and rural destinations. These patterns represent clear differences from the earlier 20^th century's “Great Migration” of African‐Americans from South to North. The recent return migration streams suggest that the South may be replacing the North as a “land of promise” for some upwardly mobile African‐Americans, and may also reflect what Carol Stack (1996) has termed a “call to home” as a motivating factor shaping recent African‐American migration to the rural South.     

Revisiting the Moderating Effect of Social Support on Strain: A Gendered Test

Agnew's General Strain Theory (GST) has both revived and advanced strain theory. It has recently been applied to topics ranging from gender differences in delinquency to differences in community crime rates. Tests of GST are now focusing on the intermediate variables that fall between GST and delinquency, such as anger and social support, but these tests have produced varying results. This paper adds to GST literature by empirically analyzing whether social support moderates individuals' responses to strain and whether this moderating effect varies by gender. Testing is conducted using data from wave six of the National Youth Survey (NYS). Results provide support for GST and suggest that there are gender differences in the types and levels of strain experienced during the late teens. Further, there is evidence to support the hypothesis that social support does moderate females' responses to certain types of strain.     

Minimax-variance L- and R-estimators of location

We consider the problem of minimax-variance, robust estimation of a location parameter, through the use of L- and R-estimators. We derive an easily checked necessary condition for L-estimation to be minimax, and a related sufficient condition for R-estimation to be minimax. Those cases in the literature in which L-estimation is known not to be minimax, and those in which R-estimation is minimax, are derived as consequences of these conditions. New classes of examples are given in each case. As well, we answer a question of Scholz (1974), who showed essentially that the asymptotic variance of an R-estimator never exceeds that of an L-estimator, if both are efficient at the same strongly unimodal distribution. Scholz raised the question of whether or not the assumption of strong unimodality could be dropped. We answer this question in the negative, theoretically and by examples. In the examples, the minimax property fails both for L-estimation and for R-estimation, but the variance of the L-estimator, as the distribution of the observation varies over the given neighbourhood, remains unbounded. That of the R-estimator is unbounded.     

Discourses about Righting the Business ← → Society Relationship

This article engages the question—what is the right business‐society relationship? We consider three perspectives that seek to address the relationship: corporate social responsibility (CSR), social entrepreneurship (SE), and conscious capitalism (CC). We take a macroapproach considering how commentary about these approaches establishes a direction for corporate practice and its relationship to key stakeholder groups. We argue that these perspectives are ‘D'iscourses that provide arguments for and articulations about the direction of corporate practice and the business‐society relationship. To organize our review of each perspective, and focus our critique, for each we highlight (a) drivers and influencers, (b) core assumptions and defining features, and (c) approaches and exemplars. Although distinct, all emphasize effective business practices as key to meeting social needs. CSR suggests legitimizing business practice; SE relocates business practices; and CC seeks to reimagine/rehabilitate business for social good. Ultimately, we conclude that these Discourses lack a clear communicative focus in terms of decision making within these organizations. We attend to this and other implications, and offer avenues for further research.