Asymptotic throughput capacity analysis of VANETs exploiting mobility diversity

Vehicular ad hoc networks (VANETs) rely on intervehicle relay to extend the communication range of individual vehicles for message transmissions to roadside units (RSUs). With the presence of a large number of quickly moving vehicles in the network, the end-to-end transmission performance from individual vehicles to RSUs through intervehicle relaying is, however, highly unreliable due to the violative intervehicle connectivity. As an effort toward this issue, this paper develops an efficient message routing scheme that can maximize the message delivery throughput from vehicles to RSUs. Specifically, we first develop a mathematical framework to analyze the asymptotic throughput scaling of VANETs. We demonstrate that in an urban-like layout, the achievable uplink throughput per vehicle from vehicle to RSUs scales as Θ(1/ log n) when the number of RSUs scales as Θ(n/log n) with n denoting vehicle population. By noting that the network throughput is bottlenecked by the unbalanced data traffic generated by hotspots of realistic urban areas, which may overload the RSUs nearby, a novel packet-forwarding scheme is proposed to approach the optimal network throughput by exploiting the mobility diversity of vehicles to balance the data traffic across the network. Using extensive simulations based on realistic traffic traces, we demonstrate that the proposed scheme can improve the network throughput approaching the asymptotic throughput capacity.

The diversity of emergency code telephone numbers in Australian hospitals: the feasibility of an Australian standard emergency code

This study explored the diversity of emergency code telephone numbers currently in use in Australian hospitals and examined the feasibility of a standard emergency code telephone number for all Australian hospitals, based on the United Kingdom experience. An email and telephone convenience survey of Australian hospitals from six states and two territories was conducted. Of the 108 hospitals surveyed, seven did not use a telephone number system and used a button/ pager system to call an emergency. Of the 101 hospitals surveyed that used a telephone number system, 40 different emergency telephone numbers were in place, and in nine hospitals the telephone number used for Code Blue (medical emergency) was different to the telephone number used for other emergency codes. With increasing mobility of staff across hospitals, uniformity of emergency code telephone numbers is required to reduce confusion, potential danger and improve staff response in emergency situations. A single Australian standard emergency telephone number for all Australian hospitals is advocated.

Does reduced mobility through fragmented landscapes explain patch extinction patterns for three honeyeaters?

1.Habitat loss and associated fragmentation are major drivers of biodiversity decline, and understanding how they affect population processes (e.g. dispersal) is an important conservation goal. In a large-scale test employing 10 × 10 km units of replication, three species of Australian birds, the fuscous honeyeater, yellow-tufted honeyeater and white-plumed honeyeater, responded differently to fragmentation. The fuscous and yellow-tufted honeyeaters are ‘decliners’ that disappeared from suitable habitat in landscapes where levels of tree-cover fell below critical thresholds of 17 and 8%, respectively. The white-plumed honeyeater is a ‘tolerant’ species whose likelihood of occurrence in suitable habitat was independent of landscape-level tree-cover. 2.To determine whether the absence of the two decliner species in low tree-cover landscapes can be explained by reduced genetic connectivity, we looked for signatures of reduced mobility and gene flow in response to fragmentation across agricultural landscapes in the Box-Ironbark region of north-central Victoria, Australia. 3.We compared patterns of genetic diversity and population structure at the regional scale and across twelve 100 km2 landscapes with different tree-cover extents. We used genetic data to test landscape models predicting reduced dispersal through the agricultural matrix. We tested for evidence of sex-biased dispersal and sex-specific responses to fragmentation. 4.Reduced connectivity may have contributed to the disappearance of the yellow-tufted honey-eater from low tree-cover landscapes, as evidenced by male bias and increased relatedness among males in low tree-cover landscapes and signals of reduced gene flow and mobility through the agricultural matrix. We found no evidence for negative effects of fragmentation on gene flow in the other decliner, the fuscous honeyeater, suggesting that undetected pressures act on this species. As expected, there was no evidence for decreased movement through fragmented landscapes for the tolerant white-plumed honeyeater. 5.We demonstrated effects of habitat loss and fragmentation (stronger patterns of genetic differentiation, increased relatedness among males) on the yellow-tufted honeyeater above the threshold at which probability of occurrence dropped. Increasing extent and structural connectivity of habitat should be an appropriate management action for this species and other relatively sedentary woodland specialist species for which it can be taken as representative.

Cultural diversity through transformative action research: translating ideas into real world impact

According to the World Bank, in 2013 more than 215 million people were living outside their countries of birth, and the United Nations Population Fund outlined that if all international migrants lived in the same place they would constitute the world’s fifth most populous country. In other words, the world’s migrant population is greater than at any other time in history and is expected to grow further. As a result of this ever-increasing human mobility, cultural diversity is a fait accompli. For this reason the mission of the Alfred Deakin Research Institute for Citizenship and Globalisation (ADRI-CG), since its inception in 2001, has been to work towards fostering intercultural understanding, human rights and social inclusion through transformative action research and within multidisciplinary approaches. Further, the Institute is mindful that academic work alone is not enough to effect lasting change in both policy and practice, and as such continually seeks strategic partnerships and effective dissemination strategies to influence public policy, and reach communities both locally and globally.

Paranormal politics and the romance of urban subcultures: youth mobility in Cassandra Clare’s and Melissa Marr’s fantasy texts

This essay examines the political and social significance of the intrusion of the supernatural into youth subcultures in two urban fantasy series: Cassandra Clare’s Mortal Instruments and Melissa Marr’s Wicked Lovely. Both series represent the idea of human youth mobility and social affiliation based on volition. The tolerant urban spaces through which their girl protagonists initially move accommodate a diversity of subcultural aesthetics. By contrast, the supernatural subcultures with which these girls become involved are fraught with conflict, and the mobility of their members is limited. Drawing on post-subcultural theory, we identify a tension between late modern and premodern social organization and political values in contemporary urban fantasy for young adults and compare how it is resolved in Clare’s and Marr’s texts.