Geographically weighted elastic net logistic regression

This paper develops a localized approach to elastic net logistic regression, extending previous research describing a localized elastic net as an extension to a localized ridge regression or a localized lasso. All such models have the objective to capture data relationships that vary across space. Geographically weighted elastic net logistic regression is first evaluated through a simulation experiment and shown to provide a robust approach for local model selection and alleviating local collinearity, before application to two case studies: county-level voting patterns in the 2016 USA presidential election, examining the spatial structure of socio-economic factors associated with voting for Trump, and a species presence–absence data set linked to explanatory environmental and climatic factors at gridded locations covering mainland USA. The approach is compared with other logistic regressions. It improves prediction for the election case study only which exhibits much greater spatial heterogeneity in the binary response than the species case study. Model comparisons show that standard geographically weighted logistic regression over-estimated relationship non-stationarity because it fails to adequately deal with collinearity and model selection. Results are discussed in the context of predictor variable collinearity and selection and the heterogeneities that were observed. Ongoing work is investigating locally derived elastic net parameters

Search and Rescue at Sea: Do New Challenges Require New Rules?

Search and rescue at sea (SAR) has been always carried out under principles of customary law of the sea obliging vessels and states to help persons whose ships are in distress at sea. International treaties define more detailed conditions and obligations to provide adequate SAR. The rationale of all these principles and rules, as well as of the associated duties affecting the obliged persons/states to carry out and organize SAR activities, was that of increasing safety at sea and taking care of seafarers and fishermen (or passengers onboard vessels) who were at sea mainly for the purpose of work. The safety of ships has increased enormously in recent decades. Therefore the number of classical SAR operations has become a minimal fraction of those actually carried out to rescue, for example, leisure yachts, migrants and cruise ship tourists that venture into dangerous waters (including the Arctic) in pursuit of adventure. Thus, the original SAR rationale has drastically changed. We need to consider whether the obligations set at the international level for rescuers and affected states should be updated to deal with current rescue missions. To deal with the migration problem in the Mediterranean, the normal SAR schemes \u2013 while not being abandoned \u2013 have been largely supplemented by other forms of international cooperation. This chapter investigates these new forms of cooperation and presents some proposals for updating the SAR international regime to meet the new challenges posed by persons venturing to sea. The Author wishes to thank Chiara Cellerino and Lorenzo Schiano di Pepe for valuable comments on the draft of this paper. Neither of them is, however, even partly responsible for any remaining mistake or inaccuracy