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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...

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,...

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...

2015

Kouritzin, Michael A., Newton, Fraser, Wu, Biao

A real-time algorithm to produce correlated random fields on general undirected graphs has been used in CAPTCHA generation and optical character recognition. This algorithm can not simulate all possible joint graph distributions but does match all marginal vertex distributions as well as...

2021-01-01

Pouria Ramazi, Mélodie Kunegel-Lion, Russell Greiner, Mark A. Lewis

2024-02-05

Heggerud, Christopher M., Xu, Jingjing, Wang, Hao, Lewis, Mark A., Zurawell, Ron W., Loewen, Charlie J. G., Vinebrooke, Rolf D., Ramazi, Pouria

Abstract (description taken from article) Toxic cyanobacterial blooms (CBs) are becoming more frequent globally, posing a threat to freshwater ecosystems. While making long-range forecasts is overly challenging, predicting imminent CBs is possible from precise monitoring data of the underlying...

2024-06-09

Heggerud, Christopher M., Xu, Jingjing, Wang, Hao, Lewis, Mark A., Zurawell, Ron W., Loewen, Charlie J. G., Vinebrooke, Rolf D., Ramazi, Pouria

Abstract (description taken from article) In this paper, we consider a diffusive-advective predator-prey system in a spatially heterogeneous environment subject to a hostile boundary condition, where the interaction term is governed by a Holling type II functional response. We investigate the...

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...

2001

Ballantyne, David, Hoffman, John, Kouritzin, Michael

Particle-based nonlinear filters provide a mathematically optimal (in the limit) and sound method for solving a number of difficult filtering problems. However, there are a number of practical difficulties that can occur when applying particle-based filtering techniques to real world problems....

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...