A model for collaboration networks giving rise to a power-law distribution with an exponential cutoff

Recently several authors have proposed stochastic evolutionary models for the growth of complex networks that give rise to power-law distributions. These models are based on the notion of preferential attachment leading to the “rich get richer” phenomenon. Despite the generality of the proposed stochastic models, there are still some unexplained phenomena, which may arise due to the limited size of networks such as protein, e-mail, actor and collaboration networks. Such networks may in fact exhibit an exponential cutoff in the power-law scaling, although this cutoff may only be observable in the tail of the distribution for extremely large networks. We propose a modification of the basic stochastic evolutionary model, so that after a node is chosen preferentially, say according to the number of its inlinks, there is a small probability that this node will become inactive. We show that as a result of this modification, by viewing the stochastic process in terms of an urn transfer model, we obtain a power-law distribution with an exponential cutoff. Unlike many other models, the current model can capture instances where the exponent of the distribution is less than or equal to two. As a proof of concept, we demonstrate the consistency of our model empirically by analysing the Mathematical Research collaboration network, the distribution of which has been shown to be compatible with a power law with an exponential cutoff.     

Experiencing Work: Values, Attitudes, and Moods

This paper describes a model (the VAM model)which integrates three of the most significantdimensions of the work experience, work values,attitudes, and moods, into one overarching framework.The VAM model proposes that a rich and more completeunderstanding of the experience of work necessitates thesimultaneous consideration of work values, attitudes,and moods. After describing how work values, attitudes, and moods, each capture key aspects ofexperiencing work, we discuss three important dimensionsalong which they vary: time, dynamism, and focus. Thesedimensions underscore the need for the simultaneous consideration of values, attitudes, and moodsfor a fuller understanding of the work experience. Wethen describe how work values, attitudes, and moods havethe potential to influence each other. Finally, we discuss the implications of the VAM modelfor understanding important organizational outcomesincluding extra-role behavior, job performance, socialloafing, absenteeism, and turnover.     

Pitfalls in multi-national long-range planning

The authors of this article argue that too many companies are not getting the benefits which should be produced by their long-range planning systems. Of the many possible explanations for this, the authors concentrate on the major pitfalls which should be avoided in order to ensure good results. The article is based upon the results of a survey of planning pitfalls among corporations in six industrialized countries.     

International alliance commitment and performance of small and medium-size enterprises: The mediating role of process control

Improving alliance performance is a critical issue that both managers and researchers have attempted to resolve. Recently scholars have suggested that firms can use alliance commitment and process controls to improve alliance performance. Yet research has only found weak support for these direct effects. In this paper we examine the mediating role of process controls on the relationship between alliance commitment and alliance performance. When tested on samples of SMEs we find support for our theoretical predictions. We then discuss the managerial implications of using commitment and process controls in SME international alliances.     

OCCUPATIONAL SEX SEGREGATION AND ECONOMIC INEQUALITY UNDER SOCIALISM:

An increase in scholarly attention to income differences between sex-typed occupations has generated a burgeoning literature. Typically-female occupations require preemployment education, not prolonged on-the-job training; receive less renumeration for work autonomy than male-typed occupations; and are concentrated in economically disadvantaged industrial sectors. However, these issues have received only preliminary consideration regarding noncapitalist societies and research has lacked an integrative, analytical focus. This study compares the earnings effects of education, type of work, and industrial sector between female- and male-dominated occupations in socialist Yugoslavia. As expected, average earnings are significantly higher in male than in female occupations. The results from the earnings regressions reveal a higher explained variance and larger economic returns to education among female- dominated occupations, especially in the managerial and professional strata. A decomposition of the earnings difference between sex-typed occupations suggests a variation in the source of inequality across skill strata. In the discussion, a comparison of capitalism and socialism reveals that while some aspects of the earnings attainment process may be unique to socialism, others are not.     

A Screening Methodology for the Identification and Ranking of Infrastructure Vulnerabilities Due to Terrorism

The extreme importance of critical infrastructures to modern society is widely recognized. These infrastructures are complex and interdependent. Protecting the critical infrastructures from terrorism presents an enormous challenge. Recognizing that society cannot afford the costs associated with absolute protection, it is necessary to identify and prioritize the vulnerabilities in these infrastructures. This article presents a methodology for the identification and prioritization of vulnerabilities in infrastructures. We model the infrastructures as interconnected digraphs and employ graph theory to identify the candidate vulnerable scenarios. These scenarios are screened for the susceptibility of their elements to a terrorist attack, and a prioritized list of vulnerabilities is produced. The prioritization methodology is based on multiattribute utility theory. The impact of losing infrastructure services is evaluated using a value tree that reflects the perceptions and values of the decisionmaker and the relevant stakeholders. These results, which are conditional on a specified threat, are provided to the decisionmaker for use in risk management. The methodology is illustrated through the presentation of a portion of the analysis conducted on the campus of the Massachusetts Institute of Technology.