Ant colony optimisation-based radiation pattern manipulation algorithm for electronically steerable array radiator antennas

A new algorithm for manipulating the radiation pattern of Electronically Steerable Array Radiator Antennas is proposed. A continuous implementation of the Ant Colony Optimisation (ACO) technique calculates the optimal impedance values of reactances loading different parasitic radiators placed in a circle around a centre antenna. By proposing a method to obtain a suitable sampling frequency of the radiation pattern for use in the optimisation algorithm and by transforming the reactance search space into the search space of associated phases, special care was taken to create a fast and reliable implementation, resulting in an approach that is suitable for real-time implementation. The authors compare their approach to analytical techniques and optimisation algorithms for calculating these reactances. Results show that the method is able to calculate near-optimal solutions for gain optimisation and side lobe reduction

Closed-form 2D angle estimation with a spherical array via spherical phase mode excitation and ESPRIT

We present a new spherical ESPRIT algorithm, being a closed-form algorithm for use in conjunction with spherical arrays that provides automatically paired source azimuth and elevation estimates. It is a numerically efficient 2D angle-of-arrival estimation algorithm which does not rely on extensive spectral searches or iterative solutions to multi-dimensional optimization problems. The spherical ESPRIT is based on the spherical phase mode excitation principle, enabling us to exploit the spherical symmetry of the antenna array by relying on a recursive relationship between spherical harmonics

Rural Malta : first results of the joint Belgo-Maltese survey project

The paper presents the first interdisciplinary results of a joint survey project in the north-west of Malta, with finds ranging from the Prehistoric till the Early Modern period. Three permanently inhabited sites were encountered dating to at least the late 6th or early 5th century BCE, with a clearer attestation in the Hellenistic/Roman and Late Antique periods. The resulting reconstructed settlement pattern of the Phoenician/Punic period suggests a managed landscape that seems to be a good reflexion of what is happening in North Africa and elsewhere in the central and western Mediterranean. At least from the Roman period on, these sites seem to have specialised on the production of olive oil.peer-reviewe