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Physical Sciences and Mathematics Commons

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Articles 1 - 5 of 5

Full-Text Articles in Physical Sciences and Mathematics

The Limits To Prediction In Ecological Systems, Brian Beckage, Louis J. Gross, Stuart Kauffman Nov 2011

The Limits To Prediction In Ecological Systems, Brian Beckage, Louis J. Gross, Stuart Kauffman

College of Agriculture and Life Sciences Faculty Publications

Predicting the future trajectories of ecological systems is increasingly important as the magnitude of anthropogenic perturbation of the earth systems grows.We distinguish between two types of predictability: the intrinsic or theoretical predictability of a system and the realized predictability that is achieved using available models and parameterizations. We contend that there are strong limits on the intrinsic predictability of ecological systems that arise from inherent characteristics of biological systems. While the realized predictability of ecological systems can be limited by process and parameter misspecification or uncertainty, we argue that the intrinsic predictability of ecological systems is widely and strongly limited …


Predictability Time Of Chaotic Cosmologies, John Max Wilson May 2011

Predictability Time Of Chaotic Cosmologies, John Max Wilson

Mahurin Honors College Capstone Experience/Thesis Projects

We examine the predictability time scales for a cosmological model from the Einstein field equations coupled to the Klein-Gordon equations for a spin zero scalar field with an interaction potential V(φ). The cosmological equations resulting from this coupling are nonlinear in the scale cosmic parameter and scalar field, thus exhibiting characteristics of chaos. The equations can be linearized in the neighborhood of equilibrium points and then diagonalized to yield its Lyapunov exponents. One e-folding time of the system is then found to estimate the predictability time. This time is compared to the Big Rip time theorized by Yurov, Moruno, and …


A Primer On Chaos And Fractals, Bruce Kessler Mar 2011

A Primer On Chaos And Fractals, Bruce Kessler

Bruce Kessler

This is a prelude to a performance of the play "Arcadia" exclusively for the science and math majors of Lipscomb University. One of the main characters of the story is a mathematical genius, and has realized the power and limitations of iterations in generating mathematical models and structures, although she is living in the early 1800's. This talk gives an introduction to the ideas of chaos theory, fractals, and randomness.


A Primer On Chaos And Fractals, Bruce Kessler Mar 2011

A Primer On Chaos And Fractals, Bruce Kessler

Mathematics Faculty Publications

This is a prelude to a performance of the play "Arcadia" exclusively for the science and math majors of Lipscomb University. One of the main characters of the story is a mathematical genius, and has realized the power and limitations of iterations in generating mathematical models and structures, although she is living in the early 1800's. This talk gives an introduction to the ideas of chaos theory, fractals, and randomness.


Strong Optical Injection Locked Semiconductor Laser For High Bit Rate Chaotic Optical Communications, Muzahim Ibrahim Azawe, Ragaad Habib Saied Jan 2011

Strong Optical Injection Locked Semiconductor Laser For High Bit Rate Chaotic Optical Communications, Muzahim Ibrahim Azawe, Ragaad Habib Saied

Turkish Journal of Physics

We present in this article how strong optical injection can produce chaotic dynamics in the output of the semiconductor laser that is preferable for perfect encrypted optical communication networks. Significant increase in the relaxation resonance frequency was found implying higher degree of enhancement in modulation bandwidth. Numerical investigations under the condition of strong optical injection locking of the slave laser shows that instabilities in the photon number was observed and had settled down after a time of in the order of carrier lifetime. The model presented can be used to extract the characteristic parameters of the injection locking for detuning …