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2013

Kouritzin, Michael, Wu, B., Newton, F.

Herein, we propose generating CAPTCHAs through random field simulation and give a novel, effective and efficient algorithm to do so. Indeed, we demonstrate that sufficient information about word tests for easy human recognition is contained in the site marginal probabilities and the...

2015-01-01

Peacock, Stephanie J., Krkošek, Martin, Bateman, Andrew W., Lewis, Mark A.

There is an increasing realization of the diverse mechanisms by which parasites and pathogens influence the dynamics of host populations and communities. In multi‐host systems, parasites may mediate food web dynamics with unexpected outcomes for host populations. Models have been used to explore...

2019-01-01

Yu Jin, Qihua Huang, Julia Blackburn, Mark A. Lewis

The study of population persistence in river ecosystems is key for understanding population dynamics, invasions, and instream flow needs. In this paper, we extend theories of persistence measures for population models in one-dimensional rivers to a benthic-drift model in two-dimensional...

2011-01-01

Molnár, Péter K., Derocher, Andrew E., Klanjscek, Tin, Lewis, Mark A.

Predicting the ecological impacts of climate warming is critical for species conservation. Incorporating future warming into population models, however, is challenging because reproduction and survival cannot be measured for yet unobserved environmental conditions. In this study, we use...

2016-01-01

Qihua Huang, Yu Jin, Mark A. Lewis

One key issue for theory in stream ecology is how much stream flow can be changed while still maintaining an intact stream ecology, instream flow needs (IFNs); the study of determining IFNs is challenging due to the complex and dynamic nature of the interaction between the stream environment and...

2005

Kouritzin, Michael, Sun, W.

Herein, we analyze an efficient branching particle method for asymptotic solutions to a class of continuous-discrete filtering problems. Suppose that t→Xt is a Markov process and we wish to calculate the measure-valued process t→μt(⋅)≐P{Xt∈⋅|σ{Ytk, tk≤t}}, where tk=kɛ and Ytk is a distorted,...

1992

Kouritzin, Michael, Heunis, A.J.

Let μ be a positive finite Borel measure on the real line R. For t ≥ 0 let et · E1 and E2 denote, respectively, the linear spans in L2(R, μ) of {eisx, s > t} and {eisx, s < 0}. Let θ: R → C such that ∥θ∥ = 1, denote by αt(θ, μ) the angle between θ · et · E1 and E2. The problems considered here...

2015-09-21

Kouritzin, Michael

2007-01-01

Nisbet, Roger, Anderson, Kurt E., McCauley, Edward, Lewis, Mark A.

Much ecological research involves identifying connections between abiotic forcing and population densities or distributions. We present theory that describes this relationship for populations in media with strong unidirectional flow (e.g., aquatic organisms in streams and rivers). Typically,...

2011-01-01

Lewis, Mark A., Derocher, Andrew E., Auger-Méthé, Marie, St. Clair, C. C.