A Generalized Model of Regional Economic Growth in the European Union

Understanding the forces driving regional growth in the EU is a major challenge for theory and policy. The opening of national borders, together with the rapid technological and scientific progress, has exposed regional economies to an extremely competitive, free-market, integrated economic environment, affecting their patterns of development. EU regions should, thus, be understood not only as national, geographic and administrative sub-divisions, but also as integral parts of the EU economic space. The paper develops a generalized econometric model for the investigation of the determinants of regional economic growth in 249 EU NUTS II regions, for the period 1990-2003. The model provides critical insight with important implications for theory and policy.DYNREG, regional economic growth, EU regions

Phase Gradient Metasurface Radome Offering Beam Angle Translation and Wideband Absorption

A novel metasurface radome design is presented which combines the properties of a rasorber as well as a phase gradient metasurface (PGMS). By replacing the traditional frequency selective surface or lossless layer, in a radar absorber (i.e. a rasorber) with a PGMS, a new structure can be realised which provides dual-functionality in terms of both beam pattern control and wideband absorption. In particular, a 60 ∘ phase gradient metasurface is designed which is composed of six different unit cells (with the same periodicity) while being placed a quarter-wavelength below two lossy (or resistive) layers. By this stack-up configuration, the radome structure supports complimentary beam steering translation whilst providing absorption bands from about 1.3 GHz to 5.5 GHz and 6.1 GHz to beyond 10 GHz. This design, to the best knowledge of the authors, is the first example of a phase gradient metasurface rasorber (PGMSR) and has many interesting applications for future multi-functional radomes. It can also help to reduce the requirements for mechanical steering, antenna beamformers as well as array phase shifting networks

A Computer Controlled Phase and Magnitude Self-Calibration Methodology for Phased Array Antennas

A circuit-based calibration system is presented for active phased arrays. In particular, to achieve the desired (and corrected) consecutive phase differences and relative magnitudes between RF channels, a computer controlled circuit system was developed for dynamic adjustment. The proof-of-concept demonstrator uses a phase sensor, phase shifters (PSs), and variable gain amplifiers, along with other active hardware, to realize a self-calibrating circuit system which achieves the required magnitude and phase for each array element. In addition, measured magnitude and phase imbalances are less than 0.10 dB and 3 ∘ , respectively. The computer-controlled feed network is then used to demonstrate that the system can automatically calibrate an active antenna array for various beam steering examples. Also, the S-band feed system can self-calibrate due to any monitored magnitude and phase drifts due to temperature changes and practical component ageing, or, other general channel offsets. This can be considered advantageous and simpler when compared to more established approaches which characterize the coupling between elements or the response of the entire array in the near- or far-field for example

HiPart: Hierarchical Divisive Clustering Toolbox

This paper presents the HiPart package, an open-source native python library that provides efficient and interpret-able implementations of divisive hierarchical clustering algorithms. HiPart supports interactive visualizations for the manipulation of the execution steps allowing the direct intervention of the clustering outcome. This package is highly suited for Big Data applications as the focus has been given to the computational efficiency of the implemented clustering methodologies. The dependencies used are either Python build-in packages or highly maintained stable external packages. The software is provided under the MIT license. The package's source code and documentation can be found at https://github.com/panagiotisanagnostou/HiPart

Tailorable optical scattering properties of the V-shaped plasmonic nano-antennas: a computationally efficient and fast analysis

We introduce an efficient computational scheme based on Macro Basis Function (MBF) method, to analyze the scattering of a plane wave by the V-shaped plasmonic optical nano-antennas. The polarization currents and the scattered fields for symmetric and anti-symmetric excitations are investigated. We investigate how the resonant frequency of the plasmonic V-shaped nanoantenna is tailored by engineering the geometrical parameters and by changing the polarization state of the incident plane wave. The computational model presented herein is faster by orders of magnitude than commercially available finite methods and is capable to characterize also other nanoantennas comprising of junctions and bends of nanorods.Comment: Final version published in JOSA A (6 pages, 9 figures). Work sponsored by DARPA/MTO Young Faculty Award #N66001-11-1-414