Hold Safety Inventory Before,At, or After the Fan‐Out Point?

We consider a product sold in multiple variants, each with uncertain demand, produced in a multi‐stage process from a standard (i.e., generic) sub‐assembly. The fan‐out point is defined as the last process stage at which outputs are generic (outputs at every subsequent stage are variant‐specific). Insights gained from an analytical study of the system are used to develop heuristics that determine the stage(s) at which safety inventory should be held. We offer a relatively‐simple heuristic that approaches globally‐optimal results even though it uses only two relatively‐local parameters. We call this the VAPT, or value‐added/processing time heuristic, because it determines whether a (local) stage should hold inventory based only on the value added at that local stage relative to its downstream stage, along with the processing time at that local stage relative to its downstream stage. Another key insight is that, contrary to possible intuition, safety inventory should not always be held at the fan‐out point, although a fan‐out point does hold inventory under a wider range of conditions. We also explore when postponement is most valuable and illustrate that postponement may often be less beneficial than suggested by Lee and Tang (1997).     

New Product Development Decision‐Making Effectiveness: Comparing Individuals,Face‐To‐Face Teams,and Virtual Teams*

A total of 411 subjects participated in two decision‐making experiments in order to examine the effectiveness of new product development project continuation decisions. Using escalation of commitment theory, in Study 1, individual versus face‐to‐face team decision‐making effectiveness was compared. Study 2, an extension of Study 1, compared the new product development decision‐making effectiveness of individuals, face‐to‐face teams, and virtual teams. A virtual team is a geographically and temporally dispersed and electronically communicating work group. In Study 2, the virtual teams communicated asynchronously via groupware technology. Our findings suggest that teams make more effective decisions than individuals, and virtual teams make the most effective decisions.     

On the parameterized complexity of the Multi-MCT and Multi-MCST problems

The comparison of tree structured data is widespread since trees can be used to represent wide varieties of data, such as XML data, evolutionary histories, or carbohydrate structures. Two graph-theoretical problems used in the comparison of such data are the problems of finding the maximum common subtree (MCT) and the minimum common supertree (MCST) of two trees. These problems generalize to the problem of finding the MCT and MCST of multiple trees (Multi-MCT and Multi-MCST, respectively). In this paper, we prove parameterized complexity hardness results for the different parameterized versions of the Multi-MCT and Multi-MCST problem under isomorphic embeddings.     

Technologiebasierte Spin-offs ?C Ein Forschungs??berblick zu Einflussgr??en ihrer Entwicklung

Technology-based spin-offs from academic institutions and private corporations represent an important proportion of young innovation-oriented ventures. They encounter specific starting conditions in terms of their core technology, the composition of the founding team, and the critical junctures during their establishment. This study analyses the state-of-the-art in quantitative empirical research on factors impacting the development of these types of firms. We present findings of both research fields and discuss them critically. Methodological and measurement issues receive particular attention in our analysis. Based on the literature review we identify factors impacting the development of both types of firms. Additionally we expose gaps in past and current research on academic and corporate spin-offs and suggest interesting opportunities for future research. Methodological shortcomings of existing studies are discussed. We derive implications for research on academic and corporate spin-offs and for the management of these types of firms.     

Governing Sleepiness: Somnolent Bodies, Discourse, and Liquid Modernity

This paper is an inquiry into how a new truth about sleepiness is being produced in a society increasingly organized around the primacy of expertise and its representation in print and visual media. Sleepiness originally described a benign, naturally occurring corporeal moment, a precursor to sleep. Increasingly, however, a new and disturbing meaning of somnolence is found in a juncture of medical and epidemiological research, social movements, and popular culture. Alongside the idea that sleepiness is a tranquil promise of repose is another, emerging truth. Sleepiness, we are told, is hazardous to self and others, and, importantly, it is each person's responsibility to resist this seductive call of the body. How, we ask, is a private, routinely occurring state of partial consciousness deprivatized, linked to public health vernaculars, and transformed into a reprobate condition? This alternative, disturbing truth about sleepiness is shown to be emerging from several disparate, seemingly unrelated caches of scientific studies, social movement literatures, magazines and newspapers, and web sites. The ideas of Michel Foucault, who pioneered the contemporary study of discourse, are shown to be particularly apropos to this inquiry, though not without some modification to make them more amenable to a contemporary society shaped increasingly by what Zygmunt Bauman calls “liquid modernity.”     

Self-control demands, cognitive control deficits, and burnout

Self-control involves inhibiting undesired behaviours and emotions, and it can be particularly relevant in the service sectors. Recent theoretical developments in cognitive and social psychology suggest that the demands on an individual of exercising self-control have an effect as a source of stress at work. In turn, burnout could be associated with being unable to meet those demands. It was expected that cognitive control deficits, as assessed by a questionnaire measure of self-reported failures in perception, memory, and action, would function as a vulnerability factor in the relationship between self-control demands and indicators of job strain. Data from 630 staff members of a German municipal administration revealed significant main effects of both self-control demands and cognitive control deficits on the burnout dimensions of emotional exhaustion and depersonalization. Both predictors were positively related to burnout. In addition, the results provided clear evidence of the vulnerability hypothesis of cognitive control deficits. By way of contrast, musculoskeletal complaints did not reflect similar main and interactive effects of self-control demands and cognitive control deficits. The requirements for self control in the service sector are expected to increase as the sector expands, and the practical implications for this are discussed.     

Towards contract based coordination of distributed product development processes with complete substitution

In distributed product development processes system integrators collaborate with suppliers to provide marketable products. We analyze contract structures in their ability to coordinate such processes. A converging supply chain with two suppliers and one system integrator is considered. Each supplier develops one component and faces uncertainty with regard to development results. For the system integrator the specifications of both components are substitutive in terms of the specification of the final product (e.g., recycling quotas). Depending on the resulting specification of the final product, the system integrator generates revenues under a maximum price clause. We apply a game-theoretic framework: the system integrator is the Stackelberg leader and the suppliers are Stackelberg followers. Assuming uniformly distributed development results, we analyze two typical development contracts: a wholesale price contract and a penalty contract. We present numerical illustrations of centralized and decentralized solutions to gain qualitative insights about the optimal decisions and the coordination ability of the two contracts. Accordingly, both contracts coordinate the supply chain only under forced compliance.     

Optimal cutpoints for random observations

For the discretisation of a continuous random variable into different categories the choice of cutpoints is essential. A popular application is the contingent valuation method. In a parametric approach, the choice of cutpoints directly effects the quality of the estimates. Therefore, optimal cutpoints are desirable in order to estimate the parameters most accurately. We consider an arbitrary number of cutpoints and determine optimal cutpoints for the exponential and Gumbel distribution and prove that the c-optimal cutpoints for the location parameter of the logistic distribution have corresponding equal category probabilities. Furthermore, we show that in the limiting case for infinitely many cutpoints there is no loss of information.     

Successes,Failures and Prospects for the Common Transport Policy

The paper reviews the development of the Common Transport Policy from a historical perspective and assesses its successes and failures as measured by its direct outputs, i.e. the regulatory, economic and other measures established to achieve its objectives. Despite significant progress with regard to the removal of barriers to competition either through positive regulation - the harmonization of social and technical standards - or through negative regulation - the liberalization and harmonization of the criteria for market access - several problems remain and solutions are outstanding with regard to the main challenges posed by sustainable mobility, namely environmental protection and social cohesion. In relevant action areas the Common Transport Policy is reluctant about following through as strict a regime of policy formulation and implementation as that adopted with regard to market-access-related regulations since 1985. The main reason, the authors argue, has to do with the implications of this for national sovereignty and for subsidiarity as currently interpreted. In the absence of a suitable regulatory framework the approach taken is that of negotiation and incremental improvement. Whether this is appropriate to the challenges faced remains an open question.