Max‐infinitely divisible models and inference for spatial extremes

For many environmental processes, recent studies have shown that the dependence strength is decreasing when quantile levels increase. This implies that the popular max‐stable models are inadequate to capture the rate of joint tail decay, and to estimate joint extremal probabilities beyond observed levels. We here develop a more flexible modeling framework based on the class of max‐infinitely divisible processes, which extend max‐stable processes while retaining dependence properties that are natural for maxima. We propose two parametric constructions for max‐infinitely divisible models, which relax the max‐stability property but remain close to some popular max‐stable models obtained as special cases. The first model considers maxima over a finite, random number of independent observations, while the second model generalizes the spectral representation of max‐stable processes. Inference is performed using a pairwise likelihood. We illustrate the benefits of our new modeling framework on Dutch wind gust maxima calculated over different time units. Results strongly suggest that our proposed models outperform other natural models, such as the Student‐t copula process and its max‐stable limit, even for large block sizes.     

How much is too much: Does the size of income support transfers affect labor supply?

Cash transfer programs pursue mainly protective objectives, but can also impact rural livelihoods by inducing investments in productive activities and changing household labor allocation. We adopt a continuous treatment approach to quantify how households’ labor supply responds to transfer size. We find a shift from paid labor to own farm labor and find that the transfer size is well within a level that would have disincentive effects on time spent on own farm activities. The switch from paid to own farm labor occurs at lower levels of transfers for labor-constrained households, and at higher levels for non-labor constrained households.     

Finding common ground: how superdiversity is unsettling social work education

For social work education in the Netherlands, the rapid transition towards superdiversity means that its capacity to adapt to this new reality and to adjust to diverse students’ backgrounds is fiercely challenged. The key aim of this article is to discuss how social work educators are dealing with the unsettling challenges of increasing diversity, based on the research outcomes of an explorative study amongst Turkish–Dutch and Moroccan–Dutch female professionals. Two different groups of educators were asked to comment on the outcomes of this study. One of the dilemmas for educators is to determine what can be considered supportive and inclusive and as reducing inequality in education. The authors used two key theoretical concepts, ‘superdiversity’ and ‘the capability approach’. These theoretical perspectives were used to deconstruct the rather massive concepts of diversity and social justice, by emphasising contextual approaches. Both perspectives stress the urgent need to involve students as ‘active agents of change’, by building a social work community to stimulate and facilitate an on-going dialogue. To successfully fulfil a pivotal role in the upward mobility or emancipation of ethnic minority students, social work education needs to be adjusted to accommodate diverse student groups.     

Uniform consistency rate of kNN regression estimation for functional time series data

In this paper, we investigate the k-nearest neighbours (kNN) estimation of nonparametric regression model for strong mixing functional time series data. More precisely, we establish the uniform almost complete convergence rate of the kNN estimator under some mild conditions. Furthermore, a simulation study and an empirical application to the real data analysis of sea surface temperature (SST) are carried out to illustrate the finite sample performances and the usefulness of the kNN approach.     

Application of hybrid framework to facilitate lean six sigma implementation: a manufacturing company case experience

This study aims to propose a hybrid framework for lean six sigma (LSS) based on the prioritisation of barriers and solution approaches, to facilitate hassles free applications for handling the challenges of wastes reduction and quality improvement. The study identifies 27 LSS barriers and 22 solution approaches through literature review and utilises feedback from industry experts. For framework, study uses fuzzy AHP-PROMETHEE to prioritise LSS barriers and solution approaches. Incorporating fuzzy sets in analytical hierarchy process (AHP) ensures the optimality of barrier weights. Whereas, preference ranking organisation method for enrichment of evaluations (PROMETHEE) helps in pairwise comparisons of solution approaches with respect to each LSS barrier, facilitating fair judgements. This research guides regarding the development of framework and checks its suitability and robustness through case application of an Indian manufacturing organisation. Authors expect that researchers and practitioners will find study useful for LSS and multi criteria decision making(MCDM) domains.     

Focusing on Focusing Events: Event Selection,Media Coverage,and the Dynamics of Contentious Meaning‐Making

Despite the prevalent assumption among scholars of social movements and contentious politics that transformative contentious events are also the focus of public attention and discussion, there has been little attempt to substantiate this. After making a case for why to focus on focusing events and suggesting that these events should be thought of as products of a dialogical contentious meaning‐making process, we develop a coverage attribute‐based method for identifying focusing events. For illustrative purposes, we apply our method to the coverage of contentious events during the “first” intifada by Israeli‐Jewish, Jewish settler, and Palestinian newspapers. Findings from analyses of 11,868 news items reveal that newspapers are likely to strategically quiet contentious events that are strategically amplified by newspapers affiliated with opposing or targeted parties, and vice versa, depending on their interpretation of these events as political opportunities or threats. Analyses of variations across and within contending parties reveal the role of structure and agency in the dialogical seesaw‐like dynamics of contentious meaning‐making.     

Deliberative democracy in the real world,the contribution of the capability approach

ABSTRACT

Drawing on Amartya Sen’s writings, this article presents the capability approach to democracy and shows its relevance for the sociological reflection and research on democratic processes conceived as ways to convert individual preferences into collective norms or decisions. Two moments are key in this respect: the formation of individual preferences and their translation into collective norms in the course of public debates. The initial sections present Sen’s conception of democracy, particularly emphasizing its articulation with the notions of ‘positional objectivity’ and ‘conversion’. Then, this conception is compared with two other mechanisms that may be used to coordinate individual decisions or preferences, namely the market and idealistic views on deliberative democracy. The article emphasizes how the capability approach departs from these two conceptions with regard to the two key concepts of capacity to aspire and capability for voice. The final section shows how Sen’s notion of democracy may open up a new field for research, namely the sociological investigation of the informational (or knowledge) basis of democracy.     

Alternative estimation methods for identifying contagion effects in dynamic social networks: A latent-space adjusted approach

Contagion effects, also known as peer effects or social influence process, have become more and more central to social science, especially with the availability of longitudinal social network data. However, contagion effects are usually difficult to identify, as they are often entangled with other factors, such as homophily in the selection process, the individual’s preference for the same social settings, etc. Methods currently available either do not solve these problems or require strong assumptions. Following Shalizi and Thomas (2011), I frame this difficulty as an omitted variable bias problem, and I propose several alternative estimation methods that have potentials to correctly identify contagion effects when there is an unobserved trait that co-determines the influence and the selection. The Monte-Carlo simulation results suggest that a latent-space adjusted estimator is especially promising. It outperforms other estimators that are traditionally used to deal with the unobserved variables, including a structural equation based estimator and an instrumental variable estimator.     

Discriminant coordinates analysis for multivariate functional data

Abstract

One of the basic statistical methods of dimensionality reduction is analysis of discriminant coordinates given by Fisher (1936 Fisher, R. A. 1936. The use of multiple measurements in taxonomic problem. Annals of Eugenics 7 (2):179–88. doi:10.1111/j.1469-1809.1936.tb02137.x.[Crossref] , [Google Scholar]) and Rao (1948). The space of discriminant coordinates is a space convenient for presenting multidimensional data originating from multiple groups and for the use of various classification methods (methods of discriminant analysis). In the present paper, we adapt the classical discriminant coordinates analysis to multivariate functional data. The theory has been applied to analysis of textural properties of apples of six varieties, measured over a period of 180?days, stored in two types of refrigeration chamber.