Mathematical Foundations of the Non-Hermitian Skin Effect.

We study the skin effect in a one-dimensional system of finitely many subwavelength resonators with a non-Hermitian imaginary gauge potential. Using Toeplitz matrix theory, we prove the condensation of bulk eigenmodes at one of the edges of the system. By introducing a generalised (complex) Brillouin zone, we can compute spectral bands of the associated infinitely periodic structure and prove that this is the limit of the spectra of the finite structures with arbitrarily large size.

Anderson Localization in the Subwavelength Regime.

In this paper, we use recent breakthroughs in the study of coupled subwavelength resonator systems to reveal new insight into the mechanisms responsible for the fundamental features of Anderson localization. The occurrence of strong localization in random media has proved difficult to understand, particularly in physically derived multi-dimensional models and systems with long-range interactions. We show here that the scattering of time-harmonic waves by high-contrast resonators with randomly chosen material parameters reproduces the characteristic features of Anderson localization.

Practical utility of a head-mounted gaze-directed beamforming system.

Assistive auditory devices that enhance signal-to-noise ratio must follow the user's changing attention; errors could lead to the desired source being suppressed as noise. A method for measuring the practical benefit of attention-following speech enhancement is described and used to show a benefit for gaze-directed beamforming over natural binaural hearing. First, participants watched a recorded video conference call between two people with six additional interfering voices in different directions.

Robustness of subwavelength devices: a case study of cochlea-inspired rainbow sensors.

We derive asymptotic formulae describing how the properties of subwavelength devices are changed by the introduction of errors and imperfections. As a demonstrative example, we study a class of cochlea-inspired rainbow sensors. These are graded metamaterials which have been designed to mimic the frequency separation performed by the cochlea.

The ASVIN Project: a study of electronic and printed veterinary science journals in the UK and Ireland.

ASVIN was a Research Support for Libraries Programme (RSLP) Funded Project, whose principal aim was to develop better co-operation between nine libraries in the veterinary and animal health field. The project examined a number of library-related areas, such as journal archiving, collection development policies, development of a common Z39.50 catalogue interface, grey literature, and printed and electronic journals.