All Outputs (61)

Low-gain Integral Control for Multi-Input, Multi-Output Linear Systems with Input Nonlinearities (2017)
Journal Article
Guiver, C., Logemann, H., & Townley, S. (2017). Low-gain Integral Control for Multi-Input, Multi-Output Linear Systems with Input Nonlinearities. IEEE Transactions on Automatic Control, 62(9), 4776-4783. https://doi.org/10.1109/TAC.2017.2691301

We consider the inclusion of a static anti-windup component in a continuous-time low-gain integral controller in feedback with a multi-input multi-output stable linear system subject to an input nonlinearity (from a class of functions that includes c... Read More about Low-gain Integral Control for Multi-Input, Multi-Output Linear Systems with Input Nonlinearities.

A necessary condition for dispersal driven growth of populations with discrete patch dynamics (2017)
Journal Article
Guiver, C., Packman, D., & Townley, S. (2017). A necessary condition for dispersal driven growth of populations with discrete patch dynamics. Journal of Theoretical Biology, 424, 11-25. https://doi.org/10.1016/j.jtbi.2017.03.030

We revisit the question of when can dispersal-induced coupling between discrete sink populations cause overall population growth? Such a phenomenon is called dispersal driven growth and provides a simple explanation of how dispersal can allow populat... Read More about A necessary condition for dispersal driven growth of populations with discrete patch dynamics.

The converging-input converging-state property for Lur’e systems (2017)
Journal Article
Bill, A., Guiver, C., Logemann, H., & Townley, S. (2017). The converging-input converging-state property for Lur’e systems. Mathematics of Control, Signals, and Systems, 29, Article 4 (2017). https://doi.org/10.1007/s00498-016-0184-3

Using methods from classical absolute stability theory, combined with recent results on input-to-state stability (ISS) of Lur{\textquoteright}e systems, we derive necessary and sufficient conditions for a class of Lur{\textquoteright}e systems to hav... Read More about The converging-input converging-state property for Lur’e systems.

Simple adaptive feedback control for positive state control systems (2016)
Presentation / Conference Contribution
Guiver, C., Logemann, H., & Townley, S. (2016, September). Simple adaptive feedback control for positive state control systems. Paper presented at POSTA 2016, the 5th International Symposium on Positive Systems, Rome, Italy

A note on the eigenvectors of perturbed matrices with applications to linear positive systems (2016)
Journal Article
Guiver, C., Hodgson, D., & Townley, S. (2016). A note on the eigenvectors of perturbed matrices with applications to linear positive systems. Linear Algebra and its Applications, 509, 143-167. https://doi.org/10.1016/j.laa.2016.07.010

A result is presented describing the eigenvectors of a perturbed matrix, for a class of structured perturbations. One motivation for doing so is that positive eigenvectors of nonnegative, irreducible matrices are known to induce norms — acting much l... Read More about A note on the eigenvectors of perturbed matrices with applications to linear positive systems.

Stability of Non-Negative Lur'e Systems (2016)
Journal Article
Bill, A., Guiver, C., Logemann, H., & Townley, S. (2016). Stability of Non-Negative Lur'e Systems. SIAM Journal on Control and Optimization, 54(3), 1176-1211. https://doi.org/10.1137/140994599

A stability/instability trichotomy for a class of nonnegative continuous-time Lur'e systems is derived. Asymptotic, exponential, and input-to-state stability concepts are considered. The presented trichotomy rests on Perron–Frobenius theory, absolute... Read More about Stability of Non-Negative Lur'e Systems.

Simple adaptive control for positive linear systems with applications to pest management (2016)
Journal Article
Guiver, C., Edholm, C., Jin, Y., Mueller, M., Powell, J., Rebarber, R., Tenhumberg, B., & Townley, S. (2016). Simple adaptive control for positive linear systems with applications to pest management. SIAM Journal on Applied Mathematics, 76(1), 238-275. https://doi.org/10.1137/140996926

Pest management is vitally important for modern arable farming, but models for pest species are often highly uncertain. In the context of pest management, control actions are naturally described by a nonlinear feedback that is generally unknown, whic... Read More about Simple adaptive control for positive linear systems with applications to pest management.

Robust set-point regulation for ecological models with multiple management goals (2015)
Journal Article
Guiver, C., Mueller, M., Hodgson, D., & Townley, S. (2016). Robust set-point regulation for ecological models with multiple management goals. Journal of Mathematical Biology, 72, 1467-1529. https://doi.org/10.1007/s00285-015-0919-7

Population managers will often have to deal with problems of meeting multiple goals, for example, keeping at specific levels both the total population and population abundances in given stage-classes of a stratified population. In control engineering... Read More about Robust set-point regulation for ecological models with multiple management goals.

The role of population inertia in predicting the outcome of stage-structured biological invasions (2015)
Journal Article
Guiver, C., Dreiwi, H., Filannino, D. M., Hodgson, D., Lloyd, S., & Townley, S. (2015). The role of population inertia in predicting the outcome of stage-structured biological invasions. Mathematical Biosciences, 265, 1-11. https://doi.org/10.1016/j.mbs.2015.04.005

Deterministic dynamic models for coupled resident and invader populations are considered with the purpose of finding quantities that are effective at predicting when the invasive population will become established asymptotically. A key feature of the... Read More about The role of population inertia in predicting the outcome of stage-structured biological invasions.

The Tour de Maths Reaches Out in Cornwall (2015)
Newspaper / Magazine
Guiver, C., Mueller, M., Lloyd, S., & Townley, S. (2015). The Tour de Maths Reaches Out in Cornwall

A stability/instability trichotomy for non-negative Lur'e systems (2014)
Presentation / Conference Contribution
Bill, A., Guiver, C., Logemann, H., & Townley, S. (2014, July). A stability/instability trichotomy for non-negative Lur'e systems. Presented at 21st International Symposium on Mathematical Theory of Networks and Systems, Groningen, The Netherlands

We identify a stability/instability trichotomy for a class of non-negative continuous-time Lur'e systems. Asymptotic as well as input-to-state stability concepts (ISS) are considered. The presented trichotomy rests on Perron-Frobenius theory, absolut... Read More about A stability/instability trichotomy for non-negative Lur'e systems.

Controllability for positive discrete–time linear systems with positive state (2014)
Presentation / Conference Contribution
Guiver, C., & Townley, S. (2014, July). Controllability for positive discrete–time linear systems with positive state. Presented at The 21st International Symposium on Mathematical Theory of Networks and Systems, Groningen, The Netherlands

Controllability of componentwise nonnegative discrete-time linear systems is considered. The key difference here from the well-established positive systems theory is that we permit the case where the input takes negative values, provided that the sta... Read More about Controllability for positive discrete–time linear systems with positive state.

Bounds on the dynamics of sink populations with noisy immigration (2014)
Journal Article
Eager, E. A., Guiver, C., Hodgson, D., Rebarber, R., Stott, I., & Townley, S. (2014). Bounds on the dynamics of sink populations with noisy immigration. Theoretical Population Biology, 92, 88-96. https://doi.org/10.1016/j.tpb.2013.12.004

Sink populations are doomed to decline to extinction in the absence of immigration. The dynamics of sink populations are not easily modelled using the standard framework of per capita rates of immigration, because numbers of immigrants are determined... Read More about Bounds on the dynamics of sink populations with noisy immigration.

Integral control for population management (2014)
Journal Article
Guiver, C., Logemann, H., Rebarber, R., Bill, A., Tenhumberg, B., Hodgson, D., & Townley, S. (2015). Integral control for population management. Journal of Mathematical Biology, 70, 1015-1063. https://doi.org/10.1007/s00285-014-0789-4

We present a novel management methodology for restocking a declining population. The strategy uses integral control, a concept ubiquitous in control theory which has not been applied to population dynamics. Integral control is based on dynamic feedba... Read More about Integral control for population management.

Model reduction by balanced truncation for systems with nuclear Hankel operators (2014)
Journal Article
Guiver, C., & Opmeer, M. R. (2014). Model reduction by balanced truncation for systems with nuclear Hankel operators. SIAM Journal on Control and Optimization, 52(2), 1366-1401. https://doi.org/10.1137/110846981

We prove the H-infinity error bounds for Lyapunov balanced truncation and for optimal Hankel norm approximation under the assumption that the Hankel operator is nuclear. This is an improvement of the result from Glover, Curtain, and Partington [SIAM... Read More about Model reduction by balanced truncation for systems with nuclear Hankel operators.

Positive state controllability of positive linear systems (2014)
Journal Article
Guiver, C., Hodgson, D., & Townley, S. (2014). Positive state controllability of positive linear systems. Systems and Control Letters, 65, 23-29. https://doi.org/10.1016/j.sysconle.2013.12.002

Controllability of positive systems by positive inputs arises naturally in applications where both external and internal variables must remain positive for all time. In many applications, particularly in population biology, the need for positive inpu... Read More about Positive state controllability of positive linear systems.

Error bounds in the gap metric for dissipative balanced approximations (2013)
Journal Article
Guiver, C., & Opmeer, M. R. (2013). Error bounds in the gap metric for dissipative balanced approximations. Linear Algebra and its Applications, 439(12), 3659-3698. https://doi.org/10.1016/j.laa.2013.09.032

We derive an error bound in the gap metric for positive real balanced truncation and positive real singular perturbation approximation. We prove these results by working in the context of dissipative driving-variable systems, as in behavioral and sta... Read More about Error bounds in the gap metric for dissipative balanced approximations.

Bounded real and positive real balanced truncation for infinite-dimensional systems (2013)
Journal Article
Guiver, C., & Opmeer, M. R. (2013). Bounded real and positive real balanced truncation for infinite-dimensional systems. Mathematical Control and Related Fields, 3(1), 83-119. https://doi.org/10.3934/mcrf.2013.3.83

Bounded real balanced truncation for infinite-dimensional systems is considered. This provides reduced order finite-dimensional systems that retain bounded realness. We obtain an error bound analogous to the finite-dimensional case in terms of the bo... Read More about Bounded real and positive real balanced truncation for infinite-dimensional systems.

A counter-example to “Positive realness preserving model reduction with H-\infty norm error bounds” (2011)
Journal Article
Guiver, C., & Opmeer, M. R. (2011). A counter-example to “Positive realness preserving model reduction with H-\infty norm error bounds”. IEEE Transactions on Circuits and Systems I: Regular Papers, 58(6), 1410-1411. https://doi.org/10.1109/tcsi.2010.2097750

We provide a counter example to the H∞ error bound for the difference of a positive real transfer function and its positive real balanced truncation stated in “Positive realness preserving model reduction with H-\infty norm error bounds” IEEE Trans.... Read More about A counter-example to “Positive realness preserving model reduction with H-\infty norm error bounds”.

Non-dissipative boundary feedback for elastic beams (2010)
Presentation / Conference Contribution
Guiver, C., & Opmeer, M. R. (2010, July). Non-dissipative boundary feedback for elastic beams. Presented at 19th International Symposium on Mathematical Theory of Networks and Systems, Budapest, Hungary

We show that a non-dissipative feedback that has been shown in the literature to exponentially stabilize an Euler-Bernoulli beam makes a Rayleigh beam and a Timoshenkobeam unstable.