Cumulants of random sum distributions

Consider a random variable S being the sum of a number N of independent and identically distributed random variables X_j (j = 1, 2, ...) where the number N is itself a non-negative integer-valued random variable independent of the X_j An explicit expression of the r-th cumulant of S is given in terms of the cumulants of N and X_j, Asymptotic properties of the distribution of S are also discussed.     

Service robotics: do you know your new companion? Framing an interdisciplinary technology assessment

Service-Robotic—mainly defined as “non-industrial robotics”—is identified as the next economical success story to be expected after robots have been ubiquitously implemented into industrial production lines. Under the heading of service-robotic, we found a widespread area of applications reaching from robotics in agriculture and in the public transportation system to service robots applied in private homes. We propose for our interdisciplinary perspective of technology assessment to take the human user/worker as common focus. In some cases, the user/worker is the effective subject acting by means of and in cooperation with a service robot; in other cases, the user/worker might become a pure object of the respective robotic system, for example, as a patient in a hospital. In this paper, we present a comprehensive interdisciplinary framework, which allows us to scrutinize some of the most relevant applications of service robotics; we propose to combine technical, economical, legal, philosophical/ethical, and psychological perspectives in order to design a thorough and comprehensive expert-based technology assessment. This allows us to understand the potentials as well as the limits and even the threats connected with the ongoing and the planned implementation of service robots into human lifeworld—particularly of those technical systems displaying increasing grades of autonomy.     

Disaster Management from a POM Perspective: Mapping a New Domain

We have reviewed disaster management research papers published in major operations management, management science, operations research, supply chain management and transportation/logistics journals. In reviewing these studies, our objective is to assess and present the macro level “architectural blue print” of disaster management research with the hope that it will attract new researchers and motivate established researchers to contribute to this important field. The secondary objective is to bring this disaster research to the attention of disaster administrators so that disasters are managed more efficiently and more effectively. We have mapped the disaster management research on the following five attributes of a disaster: (1) Disaster Management Function (decision‐making process, prevention and mitigation, evacuation, humanitarian logistics, casualty management, and recovery and restoration), (2) Time of Disaster (before, during and after), (3) Type of Disaster (accidents, earthquakes, floods, hurricanes, landslides, terrorism and wildfires etc.), (4) Data Type (Field and Archival data, Real data and Hypothetical data), and (5) Data Analysis Technique (bidding models, decision analysis, expert systems, fuzzy system analysis, game theory, heuristics, mathematical programming, network flow models, queueing theory, simulation and statistical analysis). We have done cross tabulations of data among these five parameters to gain greater insights into disaster research. Recommendations for future research are provided.     

Recurrence formula on the joint distribution of sample skewness and kurtosis under normality

Abstract

Two recurrence relations with respect to sample size are given concerning the joint distribution of skewness and kurtosis of random observations from a normal population: one between the probability density functions and the other between the product moments. As a consequence, the latter yields a recurrence formula for the moments of sample kurtosis. The exact moments of Jarque-Bera statistic is also given.     

The Gap in the Subjective Wellbeing of M��ori and New Zealand Europeans Widened Between 2005 and 2009

We compared the self-reported subjective wellbeing of M??ori and New Zealand (NZ) Europeans in two NZ national postal samples. The first sample was collected in 2005 before the global financial crisis of 2007/2010. The second was collected in 2009 while the crisis was ongoing. Both samples contained large and arguably representative samples of the indigenous peoples of NZ, M??ori (Ns = 289 and 964) as well as the now-majority group, NZ Europeans (Ns = 2,769 and 4,073). NZ Europeans?? scores on the Personal Wellbeing Index (PWI) were near-identical across the 2005 and 2009 samples. However, M??ori, who were already lower than NZ Europeans on the PWI in 2005, showed a further decrease in 2009. We argue that this gap in wellbeing widened because material advantages experienced by NZ Europeans as a social group provides a systemic buffer which protects their personal wellbeing from the impact of economic privation. M??ori, who had already experienced systemic disadvantage, were not privileged with this buffer, and thus, the effects of the 2007/2010 global financial crisis impacted their personal wellbeing to a greater extent.     

Equilibrium unemployment and the duration of unemployment benefits

This paper uses microdata to evaluate the impact on the steady-state unemployment rate of an increase in maximum benefit duration. We evaluate a policy change in Austria that extended maximum benefit duration and use this policy change to estimate the causal impact of benefit duration on labor market flows. We find that the policy change leads to a significant increase in the steady-state unemployment rate and, surprisingly, most of this increase is due to an increase in the inflow into rather than the outflow from unemployment.     

Correspondence

Cooperative learning has long been at the disposal of school teachers. However, it is often misunderstood by some teachers as just another form of collaborative group work. This article revisits cooperative learning, including a sampling of its popular variations, with practical approaches toward effectively integrating it into classroom instruction. Moreover, this article highlights the promise that cooperative learning holds for democratic education in the twenty-first century with special attention paid to its social implications.     

Performance of procrastinators: on the value of deadlines

Earlier study has shown that procrastination can be explained by quasi-hyperbolic discounting. We present a model of effort choice over time that shifts the focus from completion of to performance on a single task. We find that being aware of the own self-control problems may reduce a person??s performance as well as his or her overall well-being, which is in contrast to the existing literature on procrastination. Extending this framework to a multi-task model, we show that interim deadlines help a quasi-hyperbolic discounter to structure his or her workload more efficiently, which in turn leads to better performance. Moreover, being restricted by deadlines increases a quasi-hyperbolic discounter??s well-being. Thus, we provide a theoretical underpinning for recent empirical evidence and numerous casual observations.     

Wage dynamics and promotions inside and between firms

We focus on the dynamic relation between wage increases, promotions and job changes. In the empirical analyses, we use the Portuguese-matched employer–employee data Quadros de Pessoal. We find substantial wage returns to both promotions and job-to-job transitions. Our results are not consistent with models of full information and symmetric learning in a competitive and frictionless market. This might suggest that there is asymmetric information. An alternative explanation is that workers might search for a good match. Finally, we show that employer-reported promotions differ to a large extent from changes in hierarchical levels.