Generating Correlation Matrices With Specified Eigenvalues Using the Method of Alternating Projections

ABSTRACT

This article describes a new algorithm for generating correlation matrices with specified eigenvalues. The algorithm uses the method of alternating projections (MAP) that was first described by Neumann. The MAP algorithm for generating correlation matrices is both easy to understand and to program in higher-level computer languages, making this method accessible to applied researchers with no formal training in advanced mathematics. Simulations indicate that the new algorithm has excellent convergence properties. Correlation matrices with specified eigenvalues can be profitably used in Monte Carlo research in statistics, psychometrics, computer science, and related disciplines. To encourage such use, R code (R Core Team) for implementing the algorithm is provided in the supplementary material.     

Estimation in Epidemics with Incomplete Observations

The construction of estimating equations by martingale methods is generalized to yield estimators with explicit expressions for the parameters of the birth-and-death and the general epidemic processes when only partial observations are available. (For the birth-and-death process the death process is observed but the number of births is observed only at the end and for the general epidemic process only the removal process is observed.) For large populations, the use of the martingale central limit theorem yields asymptotic confidence regions for the parameters. Explicit expressions are derived for estimators of the variances of the large sample distributions. The range of validity and usefulness of the new estimators is determined by simulation.     

“It’s not tolerance I’m asking for, it’s respect!” A conceptual framework to differentiate between tolerance, acceptance and (two types of) respect

Due to a rising interest in empirical ‘respect’ research but at the same time a somewhat fuzzy use of the term and its semantically close neighbors, we introduce a conceptual framework. The framework draws on existing philosophical traditions and empirical psychological works alike. It is pointed out that respect, acceptance, and tolerance are all attitudes of a subject towards an object which are not aligned on one dimension, but are concerned with quite different issues. Moreover, we propose that research needs to differentiate between two very different kinds of respect. Whereas appraisal respect, acceptance, and tolerance are attitudinal reflections of a subject’s decisions on certain issues (i.e., on influence, membership, and presence), recognition respect is proposed to be an overarching processing mode, i.e., a general attitude on how to confront others.     

The aura of charisma: A review on the embodiment perspective as signaling

Charismatic leaders have consistently been shown to affect followers' performance, motivation, and satisfaction. Yet, what precisely constitutes charisma still remains somewhat enigmatic. So far, research has mainly focused on leader traits, leader behaviors, or the leader follower-relationship, and the subsequent consequences of each on followers' self-concepts. All of these approaches share the notion that leader charisma depends on an explicit interaction between leader and follower. With the present review paper, we extend extant theorizing by arguing that charisma is additionally informed by embodied signals that flow directly from either the leader or the immediate environment. We introduce the embodiment perspective on human perception and describe its utility for theoretically understanding the charismatic effect. Correspondingly, we review studies that show which concrete embodied cues can support the charismatic effect. Finally, we discuss the variety of new theoretical and practical implications that arise from this research and how they can complement existing approaches to charismatic leadership.     

The recalibration of the Danish old-age pension system

Pension reform in Denmark in the 1990s is of general interest owing to the development of a system of funded, defined contribution pension schemes based on collective agreement between the parties in the labour market. The resulting pension system seems to hold some answers to the critique of funded pension schemes. This paper analyses the process which led to the 1991 pension reform and relates the discussions and solutions found in Denmark to the international debate on pension reform.     

Imposing the Regular Ultra Passum law in DEA models

Recently there has been some discussion in the literature concerning the nature of scale properties in the Data Envelopment Model (DEA). It has been argued that DEA may not be able to provide reliable estimates of the optimal scale size. We argue in this paper that DEA is well suited to estimate optimal scale size, if DEA is augmented with two additional maintained hypotheses which imply that the DEA-frontier is consistent with smooth curves along rays in input and in output space that obey the Regular Ultra Passum (RUP) law, i.e. monotonically decreasing scale elasticities. A necessary condition for a smooth curve passing through all vertices to obey the RUP-law is presented. If this condition is satisfied then upper and lower bounds for the marginal product at each vertex are presented. It is shown that any set of feasible marginal products will correspond to a smooth curve passing through all points with a monotonic decreasing scale elasticity. The proof is constructive in the sense that an estimator of the curve is provided with the desired properties. A typical DEA based return to scale analysis simply reports whether or not a DMU is at the optimal scale based on point estimates of scale efficiency. A contribution of this paper is that we provide a method which allows us to determine in what interval optimal scale is located.