Showing papers in "CTIT technical reports series in 2018"

Updated statewide abundance estimates for the Florida manatee

Abstract: Knowing how many manatees live in Florida is critical for conservation and management of this threatened species. Martin et al. (2015) flew aerial surveys in 2011–2012 and estimated abundance in those years using advanced techniques that incorporated multiple data sources. We flew additional aerial surveys in 2015–2016 to count manatees and again applied advanced statistical techniques to estimate their abundance. We also made several methodological advances over the earlier work, including accounting for how sea state (water surface conditions) and synchronous surfacing behavior affect the availability of manatees to be detected and incorporating all parts of Florida in the area of inference. We estimate that the number of manatees in Florida in 2015–2016 was 8,810 (95% Bayesian credible interval 7,520–10,280), of which 4,810 (3,820–6,010) were on the west coast of Florida and 4,000 (3,240–4,910) were on the east coast. These estimates and associated uncertainty, in addition to being of immediate value to wildlife managers, are essential new data for incorporation into integrated population models and population viability analyses.

Geospatial data for developing nutrient SPARROW models for the Midcontinental region of Canada and the United States

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Extremum-seeking control for steady-state performance optimization of nonlinear plants with time-varying steady-state outputs

Abstract: Extremum-seeking control is a useful tool for the steady-state performance optimization of plants for which the dynamics and disturbance situation can be unknown. The case when steady-state plant outputs are constant received a lot of attention, however, in many applications time-varying outputs characterize plant performance. As a result, no static parameter-to-steady-state performance map can be obtained. Recently, we proposed an extremum-seeking control method that uses a so-called dynamic cost function to cope with these time-varying outputs. We showed that, under appropriate conditions, the solutions of the extremum-seeking control scheme are uniformly ultimately bounded in view of bounded and time-varying external disturbances, and the region of convergence towards the optimal tunable plant parameters can be made arbitrarily small. In this technical report, a proof of the local stability result is presented.

Opinion forming in the digital age

Abstract: The Internet provides fast and ubiquitous communication that enables all kinds of communities and provides citizens with easy access to vast amounts of information, although the information is not necessarily verified and may present a distorted view of real events or facts. The Internet’s power as an instant source of mass information can be used to influence opinions, which can have far-reaching consequences. This report’s purpose is to provide input into the advisory processes that determine European support for research into the effects and management of Fake News (e.g. deliberate misinformation), Echo Chambers (e.g. closed communities where biases can be reinforced through lack of diversity in opinions), and the Internet’s influence on social and political movements such as Populism; to provide insight into how innovation that takes these aspects into account can be supported. To address this aim, this report concerns socio-technical implications of the Internet related to the impact of closed communities and misinformation and makes recommendations derived from a consultation with domain experts concerning the research needed to address specific challenges. This study has used the Delphi Method, an iterative consultation mechanism aimed at consensus building within a targeted panel of experts. Three rounds of iteration were undertaken and a total of fourteen experts participated in all three rounds. The result of the consultation is 67 assertion statements that reached consensus amongst the experts in five broad themes, and these are presented in this report and summarised into key recommendations. The key overarching recommendation is that we need to understand how opinions are formed and are influenced in the current digital age. Investigations are needed to understand the underlying cognitive and emotional processes that enable peoples’ opinions to be influenced in the context of a hybrid media system that mixes online and offline channels and broadcast and interactive social media.

Static Serializability Analysis for Causal Consistency (extended version)

Abstract: Many distributed databases provide only weak consistency guarantees to reduce synchronization overhead and remain available under network partitions. However, this leads to behaviors not possible under stronger guarantees. Such behaviors can easily defy programmer intuition and lead to errors that are notoriously hard to detect. In this paper, we propose a static analysis for detecting non-serializable behaviors of applications running on top of causally-consistent databases. Our technique is based on a novel, local serializability criterion and combines a generalization of graph-based techniques from the database literature with another, complementary analysis technique that encodes our serializability criterion into first-order logic formulas to be checked by an SMT solver. This analysis is more expensive yet more precise and produces concrete counterexamples. We implemented our methods and evaluated them on a number of applications from two different domains: cloudbacked mobile applications and clients of a distributed database. Our experiments demonstrate that our analysis is able to detect harmful serializability violations while producing only a small number of false alarms.

A Test of Sex Specific Genetic Markers in the Hawaiian Hoary Bat and Relevance to Population Studies

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