We focus our attention on the classification of fuzzy time trajectories with triangular membership function, described by
a given set of individuals. To this purpose, we adopt a fullyinformational approach, explicitly recognizing the informational nature shared by the ingredients of the classification procedure: the
observed data (Empirical Information) and the classification model (Theoretical Information). In particular, by supposing that the informational paradigm has a fuzzy nature, we suggest three fuzzy clustering models
allowing the classification of the triangular fuzzy time trajectories, based on the analysis of the cross sectional and/or
longitudinal characteristics of their components (centers and spreads). Two applicative examples are illustrated. 相似文献
ABSTRACTThis paper approaches the African-European migration industry as a complex web of relations in which different actors liaise, objectives oppose each other, and roles overlap. Starting from this notion, the question emerges: How do migrants navigate this fuzzy web of migration facilitation/control? To answer this question, this paper uses a ‘trajectory ethnography’ that follows the im/mobility processes of migrants from West – and Central Africa to, and inside, Europe. In so doing, it particularly focuses on two practices that are related to the concept of social navigation. First, it concerns débrouillardise, a term that points to the power of improvisation, creativity and hustling. Second, it regards social negotiation, a term referring to the process of how migrants ‘massage’ their relations with important actors in the field. The findings stress the relational dimension of the migration industry in the sense that the functioning of one actor depends so much on the intentions and efforts of others. I conclude that we could enhance our knowledge on migration industries with studies that constantly shift between the perspective of the migrant, the social network, the facilitator and controller. Such a dynamic approach unpacks further the multiple efforts that produce migrant im/mobility. 相似文献
This study examined the trajectory of problem behaviours in domestically adopted children in South Korea as they aged. This study used the Panel Study on Korean Adopted Children's longitudinal, three‐wave data (2006, 2008 and 2010). Although data were collected at three time points, our data consisted of six time points, which covered the 5–10 years age range of the adopted children at the time of survey. One hundred sixty‐four children were included in the analysis, 75 of whom contributed to one time point, 74 to two time points and 15 to three time points. The trajectory of the problem behaviours of adopted children was examined using a piecewise hierarchical linear growth model. Because the initial exploration of the data suggested non‐linear changes in behaviour problems over time, we split the growth trajectory into two time periods: Time 1 (5–7 years) and Time 2 (7–10 years). A two‐rate model was used to estimate separate slopes for the two time periods. Results showed that the externalizing and internalizing problems of adopted children have different trajectories. Internalizing problems did not show significant changes after 5 years of age, while externalizing problems increased until 7 years of age and decreased significantly thereafter. 相似文献
Objective: The aim of this study was to analyze the age-related recession trajectory of reproductive health indices in middle-aged and elderly Chinese men.
Methods: A population-based cross-sectional study was conducted in Jiashan County, Zhejiang in 2012. Healthy men between 40 and 80 years of age were considered eligible for the study. Physical examination and the sex hormones were measured. The subjects were assessed based on the 5-item version of the International Index of Erectile Function (IIEF-5) for Erectile Dysfunction (ED), and Aging Males’ Symptoms (AMS) scale for Symptomatic Late-Onset Hypogonadism (SLOH).
Results: TG showed a decrease at age 60 years. Testis volume and TT did not show significant difference among the four age groups; cFT began to decrease at age 50 years and Bio-T decreased faster at age 50 years. SHBG and LH increased faster at age 50 and 70 years, respectively. IIEF5 score decrease faster at age 60 years. AMS scores increased faster at age 70 years. With the increase in age, the symptoms of ED and SLOH became severer.
Conclusion: Different indices on reproductive health of men showed turning points at different ages. At first, androgenic sex hormones decreased faster, and then erectile dysfunction got severer, and the last overall male syndromes declined. 相似文献
In contrast to conventional models of positively “becoming” an identity through social interaction, this article explores the inverse, negational process of “non‐becoming,” whereby actors start but do not continue along an identity career trajectory. Through cumulative attrition, interactions and encounters at key moments create an overall pattern of non‐progression. Using asexuality as an example, we identify three main trajectory stages of non‐awareness, communicative negation and non‐consolidation, each involving interactional contingencies. With a wider applicability to other repudiated identities, this model shows how even negational symbolic social objects (non‐issues, non‐events, and non‐identities) are constituted through social interaction. 相似文献
Research has demonstrated that son preference has a serious impact on the survival and well-being of female infants and children in some parts of South and East Asia, but little is known about the consequences of son preference in later childhood and adolescence. We compare children's growth trajectories in height over childhood and adolescence in China, where the level of son preference is relatively high, and the Philippines, where it is relatively low. Children's height reflects long-term nutritional status and exposure to infectious diseases, both influenced by household decision-making and, presumably, by a preference for sons. Using data from two high-quality longitudinal studies and multilevel growth models, we find that male children in China show an additional height advantage relative to their female counterparts, when compared to the sex difference in growth trajectories in the Philippines. Further analysis reveals that the additional advantage of males in China is stronger in rural areas. 相似文献
A large literature demonstrates the direct and indirect influence of health on socioeconomic attainment, and reveals the ways in which health and socioeconomic background simultaneously and dynamically affect opportunities for attainment and mobility. Despite an increasing understanding of the effects of health on social processes, research to date remains limited in its conceptualization and measurement of the temporal dimensions of health, especially in the presence of socioeconomic circumstances that covary with health over time. Guided by life course theory, we use data from the British National Child Development Study, an ongoing panel study of a cohort born in 1958, to examine the association between lifetime health trajectories and socioeconomic attainment in middle age. We apply finite mixture modeling to identify distinct trajectories of health that simultaneously account for timing, duration and stability. Moreover, we employ propensity score weighting models to account for the presence of time-varying socioeconomic factors in estimating the impact of health trajectories. We find that, when poor health is limited to the childhood years, the disadvantage in socioeconomic attainment relative to being continuously healthy is either insignificant or largely explained by time-varying socioeconomic confounders. The socioeconomic impact of continuously deteriorating health over the life course is more persistent, however. Our results suggest that accounting for the timing, duration and stability of poor health throughout both childhood and adulthood is important for understanding how health works to produce social stratification. In addition, the findings highlight the importance of distinguishing between confounding and mediating effects of time-varying socioeconomic circumstances. 相似文献
Random effects regression mixture models are a way to classify longitudinal data (or trajectories) having possibly varying lengths. The mixture structure of the traditional random effects regression mixture model arises through the distribution of the random regression coefficients, which is assumed to be a mixture of multivariate normals. An extension of this standard model is presented that accounts for various levels of heterogeneity among the trajectories, depending on their assumed error structure. A standard likelihood ratio test is presented for testing this error structure assumption. Full details of an expectation-conditional maximization algorithm for maximum likelihood estimation are also presented. This model is used to analyze data from an infant habituation experiment, where it is desirable to assess whether infants comprise different populations in terms of their habituation time. 相似文献
Previous work has shown an association between mothers' nonstandard work schedules and children's well-being. We built on this research by examining the relationship between parental shift work and children's reading and math trajectories from age 5/6 to 13/14. Using data (N=7,105) from the National Longitudinal Survey of Youth and growth curve modeling, we found that children's math and reading trajectories were related to parents' type of nonstandard shifts (i.e., evening, night, or variable). We found that having a mother who worked more years at a night shift was associated with lower reading scores, having a mother work more years at evening or night shifts was associated with reduced math trajectories, and having a father work more years at an evening shift was associated with reduced math scores. Mediation tests suggest that eating meals together, parental knowledge about children's whereabouts, and certain after-school activities might help explain these results. 相似文献