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.     

Forecasting Multivariate Road Traffic Flows Using Bayesian Dynamic Graphical Models,Splines and Other Traffic Variables

Traffic flow data are routinely collected for many networks worldwide. These invariably large data sets can be used as part of a traffic management system, for which good traffic flow forecasting models are crucial. The linear multiregression dynamic model (LMDM) has been shown to be promising for forecasting flows, accommodating multivariate flow time series, while being a computationally simple model to use. While statistical flow forecasting models usually base their forecasts on flow data alone, data for other traffic variables are also routinely collected. This paper shows how cubic splines can be used to incorporate extra variables into the LMDM in order to enhance flow forecasts. Cubic splines are also introduced into the LMDM to parsimoniously accommodate the daily cycle exhibited by traffic flows. The proposed methodology allows the LMDM to provide more accurate forecasts when forecasting flows in a real high‐dimensional traffic data set. The resulting extended LMDM can deal with some important traffic modelling issues not usually considered in flow forecasting models. Additionally, the model can be implemented in a real‐time environment, a crucial requirement for traffic management systems designed to support decisions and actions to alleviate congestion and keep traffic flowing.     

'Du hast jar keene Ahnung': African American English dubbed into German

This paper explores the translation of sociolinguistic variation by examining the ways that African American English (AAE) is dubbed into German. In discussing this ubiquitous yet poorly studied area of language use, I show that ideas about language as an index to social groupings are transferable to the degree that the ideas overlap in the cultures in question. In the case of German, if the character being dubbed is young, male and tied to the street cultures of the urban inner city, then AAE is dubbed using a form of German that has links to the urban youth cultures of north‐central Germany. The transferability of sociolinguistic variation is important to issues related to cross‐cultural communication and the ideologies that may play a role in the outcomes of that communication as well as to linguistic creativity and language style more generally.     

The Impact of Lower Level Management on Volunteers’ Workplace Outcomes in South African Non-profit Organisations: The Mediating Role of Supportive Supervisor Communication

VOLUNTAS: International Journal of Voluntary and Nonprofit Organizations - This study examined the influence of leader–member exchange on volunteers’ job satisfaction and intention to...     

Staff perceptions of staff-family interactions in nursing homes

Each year thousands of older adults are admitted to nursing homes. Following admission, nursing home staff and family members must interact and communicate with each other. This study examined relationship and communication patterns between nursing home staff members and family members of nursing home residents, as part of a larger multi-method comparative case study. Here, we report on 6-month case studies of two nursing homes where in-depth interviews, shadowing experiences, and direct observations were completed. Staff members from both nursing homes described staff–family interactions as difficult, problematic and time consuming, yet identified strategies that when implemented consistently, influenced the staff–family interaction positively. Findings suggest explanatory processes in staff–family interactions, while pointing toward promising interventions.     

Wheelchair coasting downhill is a reliable work task

OBJECTIVE: To measure test-retest reliability of physiological responses during submaximal wheelchair downhill and horizontal treadmill ergometry. DESIGN: A test-retest design was used on a convenience sample. Four male and three female non-wheelchair users, (22-43 years of age) propelled or coasted in a wheelchair under steady-state conditions. Four minute work bouts were performed at 1, 2, 3, and 4 km/hr. (0.62, 1.24, 1.86 and 2.5 mph, respectively) at 0 degrees, -2 degrees, and -4 degrees. Subjects were studied twice under each of the 12 conditions. Six tests were performed daily, with testing occurring over four days. Dependent variables included oxygen consumption, minute ventilation and heart. Intraclass correlation coefficients were determined for each set of paired tests. RESULTS: Intraclass correlation coefficients were high for absolute VO_{2}(R=0.84-0.99), V_{E} (R=0.86-0.98) and HR (R=0.95-1.0) over the range of 4 speeds and 3 inclinations studied. On average, % differences from test 1 to test 2 were less than 3%. CONCLUSION: At the treadmill speeds and inclinations (positive and negative) studied in this investigation, untrained wheelchair users responded in a physiologically reliable manner.