Besser entscheiden im Team — aber wie?

Investment committees of banks, pension funds or investment clubs meet regularly. The members decide together about the allocation and the timing of their own assets or their customers assets. This article will point out some pitfalls and chances that are typical in this decision making process. Especial focus is set on financial psychological aspects with regards to information processing and decision making processes. At the end of the article the author will indicate a sustainable way to improve the quality of team decisions.     

Können Organisationen nicht lernen? Facetten organisationaler Lernkulturen

Recently, the concept of ‘learning culture’ has entered the discussion on learning organizations and organizational learning, especially in the German speaking countries. Most of the academics, but also practitioners seem to use the term ‘learning culture’ in a particular sense as nurturing a self-directed, on-the-job learning of all employees. An implicit, often neglected assumption of this conception is that organizations can be divided into those who have a learning culture and those who do not. Although this idea of a dichotomy is also found in the discussion on learning organizations, it can be called into question. Past research has shown that (organizational) learning is a multifaceted phenomenon. Different organizations engage in very diverse kinds of learning due to the fact that they are facing varying environmental conditions. This brings us to doubt the idea of a ?one-best-way“ learning culture. Following the basic question, who learns what, how, when and why, the article presents a set of distinguishing attributes to distinguish between different types of learning cultures. Finally, yet unanswered questions and paths for future research are discussed.     

Eine integrative Theorie des Problemlösens in Gruppen: Problemlöseprozess und Problemlöseerfolg

This paper is the first paper in a three-part article series presenting an integrative theory of problem solving in groups on the basis of theory and research on group processes, problem solving and decision making. Group problem solving is differentiated into three main focuses of action, namely taskwork, group organisation and socio-emotional regulation. The present paper focuses on aspects of group organization. A theory of the structure of group mental models is developed. The mental model of problem solving groups is differentiated into a short-term and a long-term memory system. Under each memory system, several memory units are proposed containing declarative and procedural knowledge on aspects of the problem at hand and aspects of the group. Based on the assumption that success in problem solving results from the group’s success in solving various subproblems, recommendations for structuring the problem solving process are being drafted. It is suggested that during an initial orientation stage all occurring subproblems be rated according to their need for action and stored in the short term memory system. In the following action stage, the various subproblems stored in the short term memory system should be worked off in the order of their respective need for action. Based on characteristics of the subproblems at hand and on situative constraints, propositions concerning the resources needed for belabouring the various subproblems are established. Consequences with regard to the working mode of the group are derived.     

Convexity-based clustering criteria: theory,algorithms, and applications in statistics

This paper deals with the construction of optimum partitions of for a clustering criterion which is based on a convex function of the class centroids as a generalization of the classical SSQ clustering criterion for n data points. We formulate a dual optimality problem involving two sets of variables and derive a maximum-support-plane (MSP) algorithm for constructing a (sub-)optimum partition as a generalized k-means algorithm. We present various modifications of the basic criterion and describe the corresponding MSP algorithm. It is shown that the method can also be used for solving optimality problems in classical statistics (maximizing Csiszárs -divergence) and for simultaneous classification of the rows and columns of a contingency table.     

Marginal Means/Rates Models for Multiple Type Recurrent Event Data

Recurrent events are frequently observed in biomedical studies, and often more than one type of event is of interest. Follow-up time may be censored due to loss to follow-up or administrative censoring. We propose a class of semi-parametric marginal means/rates models, with a general relative risk form, for assessing the effect of covariates on the censored event processes of interest. We formulate estimating equations for the model parameters, and examine asymptotic properties of the parameter estimators. Finite sample properties of the regression coefficients are examined through simulations. The proposed methods are applied to a retrospective cohort study of risk factors for preschool asthma.     

Estimating the fundamental frequency of a periodic function

In this paper we consider the problem of estimation of the fundamental frequency of a periodic function, which has several applications in Speech Signal Processing. The problem was originally proposed by Hannan (1974) and later on Quinn and Thomson (1991) provided an estimation procedure of the unknown parameters. It is observed that the estimation procedure of Quinn and Thomson (1991) is quite involved numerically. In this paper we propose to use two simple estimators and it is observed that their performance are quite satisfactory. Asymptotic properties of the proposed estimators are obtained. The large sample properties of the estimators are compared theoretically. We present some simulation results to compare their small sample performance. One speech data is analyzed using this particular model.