Non-parametric Curve Estimation by Wavelet Thresholding with Locally Stationary Errors

An important aspect in the modelling of biological phenomena in living organisms, whether the measurements are of blood pressure, enzyme levels, biomechanical movements or heartbeats, etc., is time variation in the data. Thus, the recovery of a 'smooth' regression or trend function from noisy time-varying sampled data becomes a problem of particular interest. Here we use non-linear wavelet thresholding to estimate a regression or a trend function in the presence of additive noise which, in contrast to most existing models, does not need to be stationary. (Here, non-stationarity means that the spectral behaviour of the noise is allowed to change slowly over time). We develop a procedure to adapt existing threshold rules to such situations, e.g. that of a time-varying variance in the errors. Moreover, in the model of curve estimation for functions belonging to a Besov class with locally stationary errors, we derive a near-optimal rate for the -risk between the unknown function and our soft or hard threshold estimator, which holds in the general case of an error distribution with bounded cumulants. In the case of Gaussian errors, a lower bound on the asymptotic minimax rate in the wavelet coefficient domain is also obtained. Also it is argued that a stronger adaptivity result is possible by the use of a particular location and level dependent threshold obtained by minimizing Stein's unbiased estimate of the risk. In this respect, our work generalizes previous results, which cover the situation of correlated, but stationary errors. A natural application of our approach is the estimation of the trend function of non-stationary time series under the model of local stationarity. The method is illustrated on both an interesting simulated example and a biostatistical data-set, measurements of sheep luteinizing hormone, which exhibits a clear non-stationarity in its variance.     

欧洲化和一体化:欧盟研究中的概念

欧洲化和一体化是欧盟研究的两个核心概念。近年来越来越多地使用"欧洲化"概念不仅反映了欧洲一体化的发展历程,也反映了这种发展对成员国巨大的反作用。欧洲化既不是新瓶装旧酒,也不是根本的概念创新,而是一个很抽象的概念,它的过程和有关特征还不能作为可操作的概念来研究,大多数研究只是把国家层级的变化作为欧洲一体化的结果。欧洲化概念的使用者在诸多方面对新功能主义进行了修正,更加强调政治运行的复杂性,更加关注欧洲和国家发展之间转化机制的系统研究,强调在变化的机会结构框架中的利益诉求以及传播、学习和社会化进程。     

Approximate and exact optimal designs for paired comparisons of partial profiles when there are two groups of factors

For paired comparison experiments involving pairs of multifactor options differing in a specified number of factors the problem of finding optimal designs is considered, when only main effects are to be estimated. It is presumed that the set of factors can be partitioned into two groups such that the number of levels is constant within each group. The optimal designs for this frequently encountered case are also optimal for the corresponding choice experiments under the hypothesis that the parameters in the multinomial logit model are equal to zero.     

Exploring user experience and technology acceptance for a fall prevention system: results from a randomized clinical trial and a living lab

Background

Falls are common in older adults and can result in serious injuries. Due to demographic changes, falls and related healthcare costs are likely to increase over the next years. Participation and motivation of older adults in fall prevention measures remain a challenge. The iStoppFalls project developed an information and communication technology (ICT)-based system for older adults to use at home in order to reduce common fall risk factors such as impaired balance and muscle weakness. The system aims at increasing older adults’ motivation to participate in ICT-based fall prevention measures. This article reports on usability, user-experience and user-acceptance aspects affecting the use of the iStoppFalls system by older adults.

Methods

In the course of a 16-week international multicenter study, 153 community-dwelling older adults aged 65+ participated in the iStoppFalls randomized controlled trial, of which half used the system in their home to exercise and assess their risk of falling. During the study, 60 participants completed questionnaires regarding the usability, user experience and user acceptance of the iStoppFalls system. Usability was measured with the System Usability Scale (SUS). For user experience the Physical Activity Enjoyment Scale (PACES) was applied. User acceptance was assessed with the Dynamic Acceptance Model for the Re-evaluation of Technologies (DART). To collect more detailed data on usability, user experience and user acceptance, additional qualitative interviews and observations were conducted with participants.

Results

Participants evaluated the usability of the system with an overall score of 62 (Standard Deviation, SD 15.58) out of 100, which suggests good usability. Most users enjoyed the iStoppFalls games and assessments, as shown by the overall PACES score of 31 (SD 8.03). With a score of 0.87 (SD 0.26), user acceptance results showed that participants accepted the iStoppFalls system for use in their own home. Interview data suggested that certain factors such as motivation, complexity or graphical design were different for gender and age.

Conclusions

The results suggest that the iStoppFalls system has good usability, user experience and user acceptance. It will be important to take these along with factors such as motivation, gender and age into consideration when designing and further developing ICT-based fall prevention systems.

     

Meet the Parents? Family Size and the Geographic Proximity Between Adult Children and Older Mothers in Sweden

The aim of this study is to estimate the causal effect of family size on the proximity between older mothers and adult children by using a large administrative data set from Sweden. Our main results show that adult children in Sweden are not constrained by sibship size in choosing where to live: for families with more than one child, sibship size does not affect child-mother proximity. For aging parents, however, having fewer children reduces the probability of having at least one child living nearby, which is likely to have consequences for the intensity of intergenerational contact and eldercare.     

Should “open innovation” change innovation policy thinking in catching-up economies? Considerations for policy analyses

This paper provides a review of the current state of academic and policy-level debates on “open innovation” by elaborating on the relevance of the concept of open innovation for innovation policy-making in catching-up economies. The paper shows that paradoxes and contradictions exist between the “mainstream” innovation discourse and the development challenges of the catching-up countries that have lead to “de-contextualization” of the innovation policy discourse. The paper argues that applying the concept of open innovation in its ideal-type form to the catching-up context is likely to reinforce these de-contextualization tendencies. This problem can be remedied by more conscious attention to the basic contradictions and paradoxes, which requires a more comprehensive and systemic analytical focus on innovation and technological development at the levels of firm, industry and policy.     

Work-Related Demands Emanating from Social Change and Their Relation to Trait-Like and Occasion-Specific Aspects of Subjective Well-Being

Following current macro-level social change people are increasingly confronted with new demands encompassing perceived uncertainties concerning their job and career prospects. Studies utilizing concurrent assessments showed that perceiving a high accumulation (“load”) of such demands is negatively related to individuals’ subjective well-being. Without further evidence the interpretation of the direction of these effects, however, is equivocal. Based on the concept that individuals have a rather stable trait-like level of subjective well-being from which they may vary when confronted with changes of the external ecology, the current study examined the relationship between the reported load of demands and subjective well-being assessed as general life satisfaction and average satisfaction in domains of life (i.e., family, work, finances, and leisure). We expected that a higher load of demands corresponds to a temporary decline in well-being, while at the same time differences in the stable trait-like level of well-being account for differences in the reported demand load. For the purpose of our study, we analyzed three annual waves of assessment of German adults aged between 18 and 43 years (N = 488). Utilizing a trait-state-occasion model, we separated trait-like aspects of well-being from occasion-specific deviations. Overall, our results confirmed our expectation that effects indeed run in both directions. The higher the reported load of work-related demands, the more respondents’ well-being negatively deviated from the stable trait-like level. Beyond that a higher trait-like level of well-being corresponded to a lower demand load. Both effects revealed almost equal strength and remained stable after controlling for participants’ employment status, family status, and educational attainment.     

Social Participation in Poland: Links to Emotional Well-Being and Risky Alcohol Consumption

Social participation has been hypothesised to have both positive and negative impact on health outcomes via a variety of pathways, but previous studies have found few significant effects of social participation, and there is a lack of research from post-communist societies, which are known to be low on social capital. Using cross-sectional data from Poland on 2,970 individuals surveyed in 2009, we investigated the individual-level relationships between formal and informal social participation, emotional well-being, and risky alcohol consumption while controlling for demographic variables, socioeconomic status, employment and partnership status, health, religiosity, and generalised trust. Frequent joint activities with friends and neighbours were related to higher positive affect but also to more risky alcohol consumption. Membership in voluntary organisations was associated with more risky alcohol consumption, especially among younger males and for certain types of organisations. In contrast, volunteer work was related to higher positive affect and fewer depressive symptoms in the whole sample and to less risky alcohol consumption among the younger participants. The findings illustrate that some types of social participation, even if they are not typical of a given context (e.g., volunteering in Poland), may be more beneficial than others.