Continuous Time Channels with Interference

Khanna and Sudan \cite{KS11} studied a natural model of continuous time channels where signals are corrupted by the effects of both noise and delay, and showed that, surprisingly, in some cases both are not enough to prevent such channels from achieving unbounded capacity. Inspired by their work, we consider channels that model continuous time communication with adversarial delay errors. The sender is allowed to subdivide time into an arbitrarily large number $M$ of micro-units in which binary symbols may be sent, but the symbols are subject to unpredictable delays and may interfere with each other. We model interference by having symbols that land in the same micro-unit of time be summed, and we study $k$-interference channels, which allow receivers to distinguish sums up to the value $k$. We consider both a channel adversary that has a limit on the maximum number of steps it can delay each symbol, and a more powerful adversary that only has a bound on the average delay. We give precise characterizations of the threshold between finite and infinite capacity depending on the interference behavior and on the type of channel adversary: for max-bounded delay, the threshold is at D_{\text{max}}=\ThetaM \log\min{k, M})), and for average bounded delay the threshold is at $D_{\text{avg}} = \Theta(\sqrt{M \cdot \min\{k, M\}})$.Comment: 7 pages. To appear in ISIT 201

The Evolution of Male-Biased Dispersal under the Joint Selective Forces of Inbreeding Load and Demographic and Environmental Stochasticity

Acknowledgments We thank G. Bocedi, S. Palmer, and three anonymous reviewers for helpful comments on earlier drafts. R.C.H. was funded by the Natural Environment Research Council (1271380). Simulations were performed on the University of Aberdeen’s Maxwell high performance computing cluster.Peer reviewedPublisher PD

Inter-annual variability influences the eco-evolutionary dynamics of range-shifting

Peer reviewedPublisher PD

Lankapura: The Legacy of the Ramayana in Sri Lanka

The five articles which make up this special issue of South Asia explore the role of the Ramayana in Sri Lankan art, literature, religious ritual and political discourse in shaping Sinhala Buddhist and Tamil Saiva perceptions of the island’s distant past. Contributors work to answer the question as to when and how Sri Lanka came to be equated with the mythic ‘Lankapura’ of Valmiki’s epic, exploring both positive and negative portrayals of Ravana (ruler of Lanka antagonist of the Ramayana) in Sinhala and Tamil literature from the late medieval period to the present day. Authors work to account for the politicisation and historicisation of the Ramayana in twenty-first century Sri Lanka (including similarities to and differences from the contemporary Indian situation), along with the appropriation of Ravana as a Sinhala Buddhist cultural hero, and the incorporation of Vibhishana as a ‘guardian deity’ in the Sinhala Buddhist pantheon

Soil assessment of the Weaber Plain (Goomig) farmlands

In 2008, the Ord Irrigation Expansion Project was approved by the Western Australian Government to develop irrigated agriculture on the Weaber Plain (Goomig) As part of the environmental planning and approvals process, the WA Government was required to prepare a groundwater management plan and a hydrodynamic plan. As a result, the Department of Agriculture and Food, Western Australia (DAFWA) was requested to lead an investigative program to support a second phase of modelling. The project was divided into five components: two addressing deficiencies related to groundwater, two relating to soils and subsoils, and one addressing surface and groundwater quality aspects. This report summarises the two soil assessment components of the project