A Branch and Cut solver for the maximum stable set problem

This paper deals with the cutting-plane approach to the maximum stable set problem. We provide theoretical results regarding the facet-defining property of inequalities obtained by a known project-and-lift-style separation method called edge-projection, and its variants. An implementation of a Branch and Cut algorithm is described, which uses edge-projection and two other separation tools which have been discussed for other problems: local cuts (pioneered by Applegate, Bixby, Chvátal and Cook) and mod-k cuts. We compare the performance of this approach to another one by Rossi and Smiriglio (Oper. Res. Lett. 28:63–74, 2001) and discuss the value of the tools we have tested.     

Estimation in semiparametric models using an auxiliary model

Two classes of semiparametric and nonparametric mixture models are defined to represent general kinds of prior information. For these models the nonparametric maximum likelihood estimator (NPMLE) of an unknown probability distribution is derived and is shown to be consistent and relative efficient. Linear functionals are used for the estimation of parameters. Their consistency is proved, the gain of efficiency is derived and asymptotical distributions are given.     

An adolescent services plan to incorporate status offenders into the child welfare system

A model plan is presented for adolescent services that would facilitate the current trend to shift troubled but nondelinquent youngsters from the juvenile justice system into the child welfare system.     

THE EFFECTS OF DEGENERACY ON COST-COEFFICIENT RANGES AND AN ALGORITHM TO RESOLVE INTERPRETATION PROBLEMS

The problems of determining valid shadow prices and of performing a valid sensitivity analysis for managerial purposes are considered. For primal degenerate optima, earlier results on finding shadow prices are used to propose a clear and efficient method for finding valid cost-coefficient ranges. An example is used to demonstrate how managerial information can be obtained at degenerate optima.     

Zum Zusammenhang von Führungsqualität und Burnout- bzw. Mobbingprävention

The author discusses how workplace-related phenomena with a high socio-emotional pressure like burn out or workplace bullying relate to the leadership quality or leadership culture of an organisation. Workplace bullying and burn out are thus not understood as mere individual problems but rather are analyzed in an organisational context. The hypothesis developed in this article is that leadership quality can make a considerable contribution to preventing workplace bullying and burn out. The author develops a frame of action at which intervention levels and with what intervention forms one can pro-actively and preventively counteract workplace bullying and burn out.     

On the definition of public relations: a European view

The article confronts a U.S.-based definition of public relations as relationship management with a European view that besides a relational, argues also for a reflective paradigm that is concerned with publics and the public sphere; not only with relational (which can in principle be private), but also with public consequences of organizational behavior. The article is based on a three year research project on the European Public Relations Body of Knowledge and it reflects on the consequence of that project for definitional activities in the US practitioner and academic communities.     

Alienation,indifference and the choice of ideological position

In this paper we describe a simple model of individual voting behavior and present its implications for the candidate positioning problem under both vote and plurality maximization. Under our assumptions, some voters at the extremes of the ideological spectrum typically will not vote because they are alienated by the equilibrium location of candidates. There will also be some voters in the middle of the ideological spectrum who will not vote because they are indifferent between the equilibrium locations of the candidates. Both the abstention from alienation and from indifference arise explicitly from utility maximization. Once we allow for alienation and indifference, the two alternative candidate objective functions (vote maximization and plurality maximization) yield different outcomes. In particular, we show that under vote maximization the Median Voter (or Minimum Differentiation) outcome will not arise. On the other hand, under plurality maximization, the Median Voter outcome may or may not hold, depending on the distribution of voter preferences.We should like to thank Jerry Fusselman, Jon Hamilton, Mel Hinich, Charlie Holt and participants at seminars at the University of Virginia, Northwestern University and the 1989 Meetings of the Public Choice Society and the Economic Science Association for their helpful comments.     

Opting out of publicly provided services: A majority voting result

Our objective in this paper is to examine majority voting in an environment where both public and private alternatives coexist. We construct a model in which households are differentiated by income and have the option of choosing between publicly provided services and private services. Publicly provided services are financed through income tax revenues and made available to all citizens at zero price. Majority voting determines the tax rate. Even though preferences over tax rates are not single peaked, we provide conditions under which a majority voting equilibrium exists. We illustrate our existence result with CES preferences and a Dagum income distribution. Received: 21 December 1993 / Accepted: 2 September 1996