ELICITING A DIRECTED ACYCLIC GRAPH FOR A MULTIVARIATE TIME SERIES OF VEHICLE COUNTS IN A TRAFFIC NETWORK

The problem of modelling multivariate time series of vehicle counts in traffic networks is considered. It is proposed to use a model called the linear multiregression dynamic model (LMDM). The LMDM is a multivariate Bayesian dynamic model which uses any conditional independence and causal structure across the time series to break down the complex multivariate model into simpler univariate dynamic linear models. The conditional independence and causal structure in the time series can be represented by a directed acyclic graph (DAG). The DAG not only gives a useful pictorial representation of the multivariate structure, but it is also used to build the LMDM. Therefore, eliciting a DAG which gives a realistic representation of the series is a crucial part of the modelling process. A DAG is elicited for the multivariate time series of hourly vehicle counts at the junction of three major roads in the UK. A flow diagram is introduced to give a pictorial representation of the possible vehicle routes through the network. It is shown how this flow diagram, together with a map of the network, can suggest a DAG for the time series suitable for use with an LMDM.     

Leslie matrix models

A review of the Leslie matrix model theory and its literature 1941-1987 is presented. The point of view is that of a mathematician who focuses on the parts of the theory which are relevant to demography. Works of a decidedly applied nature are not dealt with.     

Schooling a European Identity: ethno‐cultural exclusion and nationalist resonance within the EU policy of “The European dimension of education”

This article aims to explore how the role of education as an aide in the process of “European” identity formation is being articulated in the European Union's (EU) policy of “The European dimension of education”. After having located the EU's views on education in the context of the neo‐liberal discourse on economic globalization, the article goes on to trace EU discussions of the European dimension of education historically. Subsequently, it deliberates on the understanding of European culture and identity which the European dimension of education endeavours to advance. Here a critique is developed of the policy's ethno‐culturalism, thereby excluding delineation of a collective identity in the EU. Basing itself on a notion of cultural identity which, implicitly, includes only those who fit certain versions of European historical “roots” and cultural “heritage”, the policy, it is argued, impedes a discussion of how a trans‐ethnic identity formation could be created in today's EU. Towards the end of the article, a scrutiny of the European dimension's perception of the so‐called “language diversity” in the EU seeks to illustrate this issue further.     

‘There is always this feeling of otherness’: exploring the lived experiences of visually impaired immigrant women in Canada

This paper explores the experiences of immigrant women with visual impairment in the Greater Toronto and Hamilton Area (GTHA) of Canada. Conceptually, the paper draws from feminist disability theory and critical scholarship on blindness to consider the discursive and material processes shaping women’s experiences across different socio-cultural contexts. Empirically, the paper draws from in-depth interviews with seven women. The analysis is organized around three themes. The first explores women’s understandings of visual impairment. The second examines the ways in which women’s experiences of visual impairment are shaped by meanings and attitudes that circulate within their cultural communities, and the extent to which immigration might challenge or reinforce these meanings. The third examines the shifting barriers and opportunities women face with respect to social and economic participation. We close by identifying the conceptual implications of our research.     

The Risk of James–Stein and Lasso Shrinkage

This article compares the mean-squared error (or ?₂ risk) of ordinary least squares (OLS), James–Stein, and least absolute shrinkage and selection operator (Lasso) shrinkage estimators in simple linear regression where the number of regressors is smaller than the sample size. We compare and contrast the known risk bounds for these estimators, which shows that neither James–Stein nor Lasso uniformly dominates the other. We investigate the finite sample risk using a simple simulation experiment. We find that the risk of Lasso estimation is particularly sensitive to coefficient parameterization, and for a significant portion of the parameter space Lasso has higher mean-squared error than OLS. This investigation suggests that there are potential pitfalls arising with Lasso estimation, and simulation studies need to be more attentive to careful exploration of the parameter space.     

One does not simply meme about organizations: Exploring the content creation strategies of user-generated memes on Imgur

This study explores how online publics are engaging with organizations by creating and sharing brand-related content online, outside corporate-controlled communication environments. This research employs a quantitative content analysis of memes shared on the social networking site Imgur to reveal how user-generated content conveys meaning about organizations. The analysis reveals brand-centric memes are generally classified as orphan memes, or memes that have distinct textual and visual characteristics separating them from established or emerging meme families. Memes about organizations are neither an overwhelming reflection of biting criticism or support, but rather a reflection of online public engagement with organizations that primarily use humor and textual brand features (or quiddities) to convey their commitment and satisfaction with the organization and unite meme families.     

Framing the Women’s March on Washington: Media coverage and organizational messaging alignment

Half a million citizens participated in the Women’s March on Washington the day after President Trump’s inauguration, starting a political movement. The march communicated key messages to the public directly and via the media. This study explores how media coverage framed those key messages through content analysis. Media frames mentioned all key messages, emphasizing solidarity and activation at the grassroots, and in a way that both supported and challenged organizational messages. Theoretical and practical implications are discussed.