The Polymatroid Steiner Problems

The Steiner tree problem asks for a minimum cost tree spanning a given set of terminals S⊂eqV in a weighted graph G = (V,E,c), c:E→ R⁺. In this paper we consider a generalization of the Steiner tree problem, so called Polymatroid Steiner Problem, in which a polymatroid P = P(V) is defined on V and the Steiner tree is required to span at least one base of P (in particular, there may be a single base S⊂eqV). This formulation is motivated by the following application in sensor networks – given a set of sensors S = {s₁,…,s_k}, each sensor s_i can choose to monitor only a single target from a subset of targets X_i, find minimum cost tree spanning a set of sensors capable of monitoring the set of all targets X = X₁ ∪ … ∪ X_k. The Polymatroid Steiner Problem generalizes many known Steiner tree problem formulations including the group and covering Steiner tree problems. We show that this problem can be solved with the polylogarithmic approximation ratio by a generalization of the combinatorial algorithm of Chekuri et al. (2002).We also define the Polymatroid directed Steiner problem which asks for a minimum cost arborescence connecting a given root to a base of a polymatroid P defined on the terminal set S. We show that this problem can be approximately solved by algorithms generalizing methods of Chekuri et al. (2002).A preliminary version of this paper appeared in ISAAC 2004     

Early Retirement: The Case of The Netherlands

ABSTRACT This article takes a closer look at the scope of actual early retirements, reasons for choosing early retirement, the popularity of different types of flexible retirement schemes, and the status of elderly employees within their own organization. It appears that positive reasons for choosing early retirement are more often mentioned by persons in higher professional groups, by those with a higher level of education, and by those who work in the civil service or the service sector. Neutral and negative reasons are mentioned more often by persons in lower professional groups, by those with a lower level of education, and by those working in the industrial sector. Although the motives for opting for early retirement differ, there do not appear to be great differences between categories of respondents if they have been able to choose their age at retirement personally, within specified age limits. Approximately a quarter of the respondents indicated they would leave work at the age of 60, even if this meant a 30% drop in net income.     

Trust in leadership: A multi-level review and integration

Leaders have been argued to play a key role in determining organizational effectiveness across all levels (e.g., individual, team, unit) that exist within organizations. A key component in a leader's ability to be effective within such environments is the degree to which subordinates and co-workers trust him/her. Therefore, it is not surprising that researchers and practitioners alike are interested in identifying the mechanisms through which trust in leadership can be developed as well as those factors which moderate this relationship [e.g., Gillespie, N. A., Mann, L. (2004). Transformational leadership and shared values: The building blocks of trust. Journal of Managerial Psychology, 19, 588–607; Kouzes and Posner, 1995; Roberts, K. H., O'Reilly, C. A. (1974). Failures in upward communication in organizations: Three possible culprits. Academy of Management Journal, 17, 205–215; Whitener, E. M. (1997). The impact of human resource activities on employee trust. Human Resource Management Review, 7, 389–404]. Despite this, research that has addressed the factors that foster trust in leaders and the outcomes of this trust has been disjointed and, as yet, no comprehensive model has been presented to systematically examine these factors. Therefore, the purpose of this article will be to present an integrative model of trust in leadership.     

Grey Advantage: New strategies for the old

With nearly one fifth of the population of the industrialized world soon to be beyond a traditional retirement age, businesses need to re-appraise their attitudes towards both older workers and older customers. Whilst some public and private sector organizations may have signalled such intentions, the gap between the rhetoric and reality of ‘third age’ employment and grey market development is still substantial. Analysing the ‘Age-Quake’, this article reviews current ageing population trends and associated business agendas. Using case study analysis, it then challenges three perceived ‘grey discontinuities’, as well as the traditional perception of simplistic step-change declines in physical and mental abilities and economic activity at the traditional retirement age. Deriving from this, the article challenges the older received wisdom by offering the individual assessment of ‘third-agers’ in terms of abilities as employees and tastes as customers as two generic strategies to assist managers in the strategic alignment of their organizations in pursuit of “grey advantage”.     

Emerging organizational forms: Work and organization in the 21st century

This article begins with the premise that there is continuous and accelerating change in the Western World in the nature of work and how it is organized. An important contributory force is information technology — itself changing rapidly.When the dynamics of the external environment of organizations are added to changes in IT, we will see new forms of organizations evolving in the business world, such as the ‘starburst’ and ‘internal market’ structures.Michael Scott Morton supplies a diagram to illustrate the framework of research which the ‘1990s’ program at MIT is following — how to balance the dynamic tension between external forces and the internal dimensions of organizations to reward shareholders adequately. He refers to one of Peter Senge's ideas in The Fifth Dimension which is central in creating an organization which learns how to innovate constantly: System Thinking — the search for systemic patterns. It reinforces Scott Morton's argument, and seems a particularly appropriate discipline in a continuously turbulent business environment.     

Animating leadership: Crisis and renewal of governance in 4 mythic narratives

This paper analyzes four animated films in order to explore themes of leadership crises and leadership emergence. Drawing on psychoanalysis and structuralist film studies, this paper explores leadership emergence as a mythic structure within the four films, arguing that these myths are structured around a struggle of a young novice against an evil power figure, and the overcoming of this figure through a process of self-discovery and maturation. Central themes include the relations between self-realization of leaders and the social harmony, the battle with evil leaders as an ego-struggle, and exile and journey as a precursor to mature leadership competence. The paper attempts to show how, following Miendl et al. [Meindl, J. R., Erlich, S. B. & Dukerich, J. M. (1985). The romance of leadership. Administrative Science Quarterly, 30, 78–102] leadership myths often conflate individual psychological well-being with social well-being, and add to this perspective that such a conflation may be key to understanding leadership myths as projections of internal psychological dynamics. More generally, it is argued that treating popular culture such as animated allegories as contemporary myth offers scholars a view into popular conceptions of leadership, possible illuminating the relationships between leadership and social organization.     

Future of European human resource management: A contingent approach

The ability to cope with an increasingly open European Market, enhanced mobility between nation states and the threat of competition from the Far East will be highly prized organisational skills in the third millenium. Many commentators have argued that ‘Europeanisation’ (broadly defined) is an irreversible process and companies will have to cope proactively with this or perish. However, in this article we argue that many of these predictions are based on an uncritical acceptance of the ‘internationalisation’ thesis, and on subjective assessments of possible future trends — rather than on sound empirical research within strong theoretical frameworks. Accordingly, this article takes a critical look at some widely-held assumptions about internationalisation, Europeanisation and the (potential) development of European Human Resource Management (EHRM). It then goes on to suggest a framework of research which will be more able to capture future developments in EHRM and thereby facilitate more robust exchanges on strategic HRM with those companies operating in a European setting.     

The contingent nature of best practices in national competitiveness: The case of American and Japanese innovation processes

We propose that the differences in competitiveness of companies from different countries is not just a question of the adoption of ‘better’ management models, as conventional wisdom would have us believe; rather, we contend that national competitiveness can change radically over time without significant changes in management practices. Contrary to much of the management literature we hold that changes in the global business environment often determine to a large degree the competitiveness of companies. Based on our assumptions we offer four specific lessons of how companies can increase their competitiveness within the constraints of the socio-cultural context in which they operate.     

Tenacity: The American Pursuit of Corporate Responsibility

This article attempts to answer the question, “What are the most important ideas from serving as Executive Editor of the five‐year history project that culminated in the book, Corporate Responsibility: The American Experience?” The ideas focus on (1) clarifying the phenomenon of tenacity; (2) looking at three foundations of our tenacity; and (3) asking “How fragile is our tenacity?” This article also presents three foundational principles that underlie the American experience of corporate responsibility. First, the Checks & Balances Principle tells us that there are checks and balances in democratic capitalism which give us confidence that the pursuit of economic goals will be moderated for the common good. Second, the Moral Projection Principle shows that there is good reason to consider the corporation not only as a legal person under corporate law but also as a moral person. And, last, the Moral Common Ground Principle reflects that there are shared moral values ascertainable by well‐developed consciences in individuals and in corporations. The article concludes with this argument: The tenacity regarding corporate responsibility that has been so characteristic of American capitalism is fragile—calling for serious vigilance if it is to endure.     

European management: An emerging competitive advantage of European nations

This article extends the debate begun in the June 1992 issue of EMJ when the authors first criticized Michael Porter's explanatory framework in his Competitive Advantage of Nations (1990), over the role of national culture on the competitive advantage of nations. In this paper, Frans van den Bosch and Arno van Prooijen stress that Europe is a locus of competitive advantage if one is prepared to pay attention to the possibility of ‘European Management’ as a potential asset of European firms. In this connection, the transnationalization of European firms is of importance.     

The Effect of a Longer Eligibility to a Labour Market Programme for Dismissed Workers

Liste di Mobilità is an Italian programme targeted to dismissed workers. It combines a ‘passive’ and an ‘active’ component. Eligibility duration varies with the worker's age at dismissal. Using a new panel data set, we identify the impact of extending the duration of eligibility on re‐employment probabilities and wages, via Regression Discontinuity Design. We validate the design by a set of overidentification tests. For most subgroups we find no significant impact, with a peculiar pattern for women entitled to monetary benefits. A major negative impact emerges for workers aged 50 or more granted monetary benefits, likely due to the fact that they can use the programme as a bridge to retirement.     

Managerial value and belief systems in a cross-national context: The case of thetrivial significance

This article discusses potential theoretical and methodological flaws in value-based research in a cross-national context. Using data from a comparative study of American and Indian CEOs, it is shown that some managerial beliefs and value systems do vary as a function of national background. While this is neither surprising nor exciting, whether this significantheterogeneity offers nontrivial predictive utilityin explaining the observed variance in a large number of structural, strategic, and other critical variables at the organizational level is the more important question. This study offers preliminary evidence to the contrary.In this era of multinational corporations and an emerging global market for executive and managerial talent, the question of whether some managerial beliefs and value systems persist in spite of extensive acculturation and socialization has been an issue of concern — especially in the United States because of a large and continuing flow of immigrants. Our results show in essence that this question, though important and interesting from a sociological angle, is perhaps not as crucial as one might suppose in influencing the strategic thrust, structural configurations, or certain aspects of performance of an organization.     

The Future is Now: Reducing Psychological Distance to Increase Public Engagement with Climate Change

Many people perceive climate change as psychologically distant—a set of uncertain events that might occur far in the future, impacting distant places and affecting people dissimilar to themselves. In this study, we employed construal level theory to investigate whether a climate change communication intervention could increase public engagement by reducing the psychological distance of climate change. Australian residents (N = 333) were randomly assigned to one of two treatment conditions: one framed to increase psychological distance to climate change (distal frame), and the other framed to reduce psychological distance (proximal frame). Participants then completed measures of psychological distance of climate change impacts, climate change concern, and intentions to engage in mitigation behavior. Principal components analysis indicated that psychological distance to climate change was best conceptualized as a multidimensional construct consisting of four components: geographic, temporal, social, and uncertainty. Path analysis revealed the effect of the treatment frame on climate change concern and intentions was fully mediated by psychological distance dimensions related to uncertainty and social distance. Our results suggest that climate communications framed to reduce psychological distance represent a promising strategy for increasing public engagement with climate change.     

Psychosocial safety climate as an antecedent of work characteristics and psychological strain: A multilevel model

Abstract

Psychosocial safety climate (PSC) refers to a specific organizational climate for the psychological health of workers. It is largely determined by management and at low levels is proposed as a latent pathogen for psychosocial risk factors and psychological strain. Using an extended Job Demands-Control-Support framework, we predicted the (24 month) cross-level effects of PSC on psychological strain via work conditions. We used a novel design whereby data from two unrelated samples of nurses working in remote areas were used across time (N=202, Time 1; N=163, Time 2), matched at the work unit level (N= 48). Using hierarchical linear modelling we found that unit PSC assessed by nurses predicted work conditions (workload, control, supervisor support) and psychological strain in different nurses in the same work unit 24 months later. There was evidence that the between-group relationship between unit PSC and psychological strain was mediated via Time 2 work conditions (workload, job control) as well as Time 1 emotional demands. The results support a multilevel work stress model with PSC as a plausible primary cause, or “cause of the causes”, of work-related strain. The study adds to the literature that identifies organizational contextual factors as origins of the work stress process.     

Being flexible and accommodating diversity: The challenge for multinational management

This article presents an opposing view to the current populist position that corporate culture can be utilised to bind the multinational together. It critically examines the appropriateness of corporate culture as a ‘soft’ control mechanism, concluding that highly committed, inculcated managers (believers) may actually be a barrier to the goals of flexibility, responsiveness and innovativeness in the face of rapidly changing, diverse global operations. However, the calculatively compliant manager is not proferred as an alternative. Rather, we argue that the quest for conformity to a given corporate culture may be counterproductive. The real challenge for multinationals is to develop mechanisms that encourage mixed voices and messages, and support a diversity of perspectives. It is suggested that multinationals might even look at the university model, in which it has long been recognised that knowledge advances in a climate of critique and dissent.     

The managerial implications of networking

Recent years have shown a proliferation of publications about interaction and networks. All in all, these articles and books tend to focus on the formulation of theory and hypotheses. Despite the relevance of further development of theoretical thought, managers display more interest in scientifically-based recommendations with direct practical relevance. Wim Biemans presents the findings of an in-depth analysis of seventeen cases of new product development in the Dutch medical equipment industry by discussing eight critical success factors related to networking. He maintains that, while the existence of networks offers great opportunities to management, the practice of networking involves some serious potential pitfalls and problems as well. The conclusions are summarized by The Five C's of Innovation Management.“Marketing can be seen as relationship management: creating, developing, and maintaining a network in which the firm thrives”(Gummesson).     

The stability of strategic alliances: Characteristics, factors and stages

This paper presents a theoretical framework for understanding the evolutionary dynamics of strategic alliances. Using an integrated process model, we analyze the conceptual characteristics and antecedents of the stability of strategic alliances. The primary purpose of this study is to (1) conceptualize and characterize alliance stability to fill the academic gap in the literature, and (2) identify a range of endogenous factors underlying alliance stability across four developmental stages — partner selection, structuring/negotiation, implementation and performance evaluation — so as to fill the managerial relevance gap. From the discussion, we develop a number of propositions to facilitate future empirical testing of our conceptual model. Finally, we indicate some key implications for theoretical research and managerial practice.     

Construct validation in leadership research: Explication and illustration

The field of leadership typically employs constructs—variables that cannot be directly measured—in its research. Yet, our measures are rarely subjected to systematic assessment of their construct validity. This paper presents arguments about the importance of the construct validation process and illustrates why such concerns are well founded by examining the most commonly used measure of subordinate-perceived leader–member exchange, the LMX-7 scale. Using bakery workers (N = 379) and employed MBA students (N = 350), discriminant validity was investigated by exploratory factor analysis in the first sample, confirmatory factor analysis in the second sample, and correlation and multiple regression analysis in a subset of the second sample (N = 220). The results suggested poor subordinate LMX-7 discriminant validity and that subordinate LMX-7 scores were substantially predicted by measures of supportive leadership and supervisor satisfaction (R² = .71). Implications for future LMX theory and research are discussed as well as the types of construct validity evidence that we need to gather on our research instruments before and while they are employed in substantive studies of leadership phenomena.