Random Information Spread in Networks

Let G=(V,E) be an undirected loopless graph with possible parallel edges and s and t be two vertices of G. Assume that vertex s is labelled at the initial time step and that every labelled vertex copies its labelling to neighbouring vertices along edges with one labelled endpoint independently with probability p in one time step. In this paper, we establish the equivalence between the expected s-t first arrival time of the above spread process and the notion of the stochastic shortest s-t path. Moreover, we give a short discussion of analytical results on special graphs including the complete graph and s-t series-parallel graphs. Finally, we propose some lower bounds for the expected s-t first arrival time.Comment: 17 pages, 1 figur

Electrical properties of epitaxial films of PbTe, PbSe and PbS

Imperial Users onl

A Survey of Agent-Based Modeling Practices (January 1998 to July 2008)

In the 1990s, Agent-Based Modeling (ABM) began gaining popularity and represents a departure from the more classical simulation approaches. This departure, its recent development and its increasing application by non-traditional simulation disciplines indicates the need to continuously assess the current state of ABM and identify opportunities for improvement. To begin to satisfy this need, we surveyed and collected data from 279 articles from 92 unique publication outlets in which the authors had constructed and analyzed an agent-based model. From this large data set we establish the current practice of ABM in terms of year of publication, field of study, simulation software used, purpose of the simulation, acceptable validation criteria, validation techniques and complete description of the simulation. Based on the current practice we discuss six improvements needed to advance ABM as an analysis tool. These improvements include the development of ABM specific tools that are independent of software, the development of ABM as an independent discipline with a common language that extends across domains, the establishment of expectations for ABM that match their intended purposes, the requirement of complete descriptions of the simulation so others can independently replicate the results, the requirement that all models be completely validated and the development and application of statistical and non-statistical validation techniques specifically for ABM.Agent-Based Modeling, Survey, Current Practices, Simulation Validation, Simulation Purpose

The Effects of Pension Rights and Retirement Age on Training Participation: Evidence from a Natural Experiment

This paper uses a natural experiment approach to identify the effects of an exogenous change in future pension benefits on workers' training participation. We use unique matched survey and administrative data for male employees in the Dutch public sector who were born in 1949 or 1950. Only the latter were subject to a major pension reform that diminished their pension rights. We find that this exogenous shock to pension rights postpones expected retirement and increases participation in training courses among older employees, although exclusively for those employed in large organizations.natural experiment, retirement, training

The effects of pension rights and retirement age on training participation: Evidence from a natural experiment

This paper uses a natural experiment approach to identify the effects of an exogenous change in future pension benefits on workers'' training participation. We use unique matched survey and administrative data for male employees in the Dutch public sector who were born in 1949 or 1950. Only the latter were subject to a major pension reform that diminished their pension rights. We find that this exogenous shock to pension rights postpones expected retirement and increases participation in training courses among older employees, although exclusively for those employed in large organizations.labour economics ;

The effects of pension rights and retirement age on training participation: Evidence from a natural experiment

This paper uses a natural experiment approach to identify the effects of an exogenouschange in future pension benefits on workers’ training participation. We use uniquematched survey and administrative data for male employees in the Dutch public sectorwho were born in 1949 or 1950. Only the latter were subject to a major pension reformthat diminished their pension rights. We find that this exogenous shock to pension rightspostpones expected retirement and increases participation in training courses amongolder employees, although exclusively for those employed in large organizations.education, training and the labour market;

Training Background and Early Retirement

Several studies show that employees with firm-specific skills are more likely to be covered by employer-sponsored pension schemes than workers with general skills. Therefore it can be expected that workers with firm-specific skills retire earlier. This paper tests this prediction using US data from the National Longitudinal Survey of Older Men. We find that workers who participated in firm-specific training in their early careers retire earlier than workers with a general training background. This indicates that shared investments in firm-specific training are embedded in implicit contracts that induce early retirement. The results remain robust when controlling for technological change and work commitment.retirement, training, deferred compensation

Training and early Retirement

In this paper we analyze how retirement behavior is affected by a worker’s firm-specific or general training history. Using US data from the National Longitudinal Survey of Older Men and controlling for the effects of technological change and workers’ retirement preferences, we find that workers with a firm-specific training history retire earlier than workers with a general training background. This indicates that shared investments in firm-specific training are embedded in upward sloping earning profiles that create productivity-wage differentials for older workers.education, training and the labour market;