Attitudes Towards Saving in Polish Society During Transformation

Since 1999 the complex reform of the old-age pension system was introduced in Poland and the process of changes is still ongoing. The multi-pillar system replaced the pay-as-you-go system. Voluntary third pillar will guarantee higher pensions for those that decide to save more. However, the systemic changes were placed in the new market economy just being implemented in Poland. New economic reality involves serial of processes influencing management of the current budget. On one hand the principles of market economy impose rigorous environment for management of the disposal income while on the other the dynamically developing market of goods, services and modern banking systems create pressure to spend. The evolution of pension system naturally poses questions concerning how the savings and saving behaviour are perceived in the Polish society during economic transformation. The results of survey conducted in the end of 2004 show that the precaution and life cycle motives of saving are observable in the Polish society but restrain seems to be marginal. In addition, attitudes towards saving are varied by some demographic and socio-economic features. These findings confirm statements referring to relation between the growth in material and social standards and acceptance of consumption style of life [i.e. Katona: 1975, Psychological Economics (Elsevier, New York); Lunt and Livingston: 1992, Mass Consumption and Personal Identity (Open University Press, Buckingham)]. Poles with higher social-economic position are rejecting self-restraint shifting towards consumerism. Nevertheless, common opinion of the respondents advocated savings is in contrary with declared avoiding restraint what is in line with other authors describing attitudes towards saving in conflict [Webley and Nyhus: 2001, Everyday representation of the Economy (WUV Universitätsverlag, Wien)].     

Empirical likelihood confidence intervals under imputation for missing survey data from stratified simple random sampling

Missing observations due to non‐response are commonly encountered in data collected from sample surveys. The focus of this article is on item non‐response which is often handled by filling in (or imputing) missing values using the observed responses (donors). Random imputation (single or fractional) is used within homogeneous imputation classes that are formed on the basis of categorical auxiliary variables observed on all the sampled units. A uniform response rate within classes is assumed, but that rate is allowed to vary across classes. We construct confidence intervals (CIs) for a population parameter that is defined as the solution to a smooth estimating equation with data collected using stratified simple random sampling. The imputation classes are assumed to be formed across strata. Fractional imputation with a fixed number of random draws is used to obtain an imputed estimating function. An empirical likelihood inference method under the fractional imputation is proposed and its asymptotic properties are derived. Two asymptotically correct bootstrap methods are developed for constructing the desired CIs. In a simulation study, the proposed bootstrap methods are shown to outperform traditional bootstrap methods and some non‐bootstrap competitors under various simulation settings. The Canadian Journal of Statistics 47: 281–301; 2019 © 2019 Statistical Society of Canada     

A survey of scheduling problems with late work criteria

The paper presents the first complete survey of scheduling problems with the late work criteria. Late work objective functions estimate the quality of a schedule based on durations of late parts of jobs, not taking into account the amount of delay for fully late jobs. The paper provides a formal definition of the late work parameter and compares the criteria based on it with other classical performance measures. It shows the relationship between the late work model and the imprecise computation model known from the hard real-time literature. Moreover, the paper presents a few real world applications of the late work objective function. The paper lists results obtained for nearly forty problems of scheduling jobs on a single machine, parallel (identical and uniform) machines and dedicated machines, investigated in the literature since 1984.     

Internal Migration and Life Satisfaction: Well-Being Paths of Young Adult Migrants

Internal migration is typically associated with higher income, but its relation with life satisfaction remains unclear. Is internal migration accompanied by an increase in life satisfaction and does this increase depend on the reason for moving? What are the aspects of life underlying overall life satisfaction that change following migration? These questions are addressed using longitudinal data from the Swedish Young Adult Panel Study. Migration is defined as a change in municipality of residence. Comparing migrants to non-migrants, it is found that internal migration is accompanied by a short to medium term increase in life satisfaction for those who move due to work (work migrants), as well as those who move for other reasons (non-work migrants). However, only work migrants display an improvement in life satisfaction that remains significant 6 or more years following the move. Work and non-work migrants also differ in the aspects of life that change following migration. For work migrants the move is accompanied by an improvement in occupational status positively associated with well-being 6–10 years after the move. For non-work migrants, a persisting increase in housing satisfaction follows migration, but this housing improvement is accompanied by only a short to medium term increase in overall well-being.     

Comparing the relative abilities of tree species to cool the urban environment

Increasing urbanisation poses numerous challenges to human quality of life. Cities are particularly vulnerable to the urban heat-island effect, which will be amplified by climate change. Increasing tree cover may be one of the most cost-effective ways of moderating urban temperatures. Trees cool their surroundings by casting shade, reflecting solar radiation, transpiring, and intercepting rainfall that subsequently evaporates. However, the potential of trees to reduce the urban heat-island effect is underutilised. The aim of this study was to synthesise understanding of the relative abilities of different tree species to provide urban cooling in temperate regions of the world and thereby develop a pragmatic approach for choosing those trees that have greatest potential in that regard. Based on a literature review and semi-structured interviews with leading experts, we developed a series of scenarios to illustrate the impacts of a tree’s cooling mechanisms and tree species’ attributes on components of the surface-energy balance equation. This enabled us to select parameters and propose simple equations that can be used to compare the relative abilities of tree species in relation to each of the cooling mechanisms. The parameters selected were for: transpiration – crown diameter, Leaf Area Index (LAI), canopy aspect ratio, and stomatal conductance or growth rate; reflection – albedo, crown diameter and LAI; shading – canopy aspect ratio, crown diameter, LAI and tree height. The approach is intended for use by urban planners and managers who wish to make informed decisions about which tree species to select for planting to counter the urban heat-island effect.