Using dual-network-analyser for communities detecting in dual networks

Background Representations of the relationships among data using networks are widely used in several research fields such as computational biology, medical informatics and social network mining. Recently, complex networks have been introduced to better capture the insights of the modelled scenarios. Among others, dual networks (DNs) consist of mapping information as pairs of networks containing the same set of nodes but with different edges: one, called physical network, has unweighted edges, while the other, called conceptual network, has weighted edges. Results We focus on DNs and we propose a tool to find common subgraphs (aka communities) in DNs with particular properties. The tool, called Dual-Network-Analyser, is based on the identification of communities that induce optimal modular subgraphs in the conceptual network and connected subgraphs in the physical one. It includes the Louvain algorithm applied to the considered case. The Dual-Network-Analyser can be used to study DNs, to find common modular communities. We report results on using the tool to identify communities on synthetic DNs as well as real cases in social networks and biological data. Conclusion The proposed method has been tested by using synthetic and biological networks. Results demonstrate that it is well able to detect meaningful information from DNs.

Design and Implementation of Fractal Antenna For SWB applications

The miniaturized wideband antennas are used widely in modern communication systems. Fractal geometries can be used to fabricate multi-band and broad-band antennas. One of the main components of super wideband communication systems is a SWB antenna. Applying fractals to the antenna elements allows for smaller size, multiband and broad band properties. The term fractal, which means broken or irregular fragments, each of which having reduced size and copy of the whole. This paper focuses the design and analysis of star triangular fractal antenna. The designed structure offers maximum gain and bandwidth ratio greater than 10:1 for SWB (2.18 to 44.5 GHz) applications. The purpose of the iteration is to reduce the size of the fractal antenna. The proposed antenna has been analysed for the part of SWB band from 1 GHz to 30 GHz. The proposed antenna structure can be designed using design equations and simulated using computer simulation technology (CST). Finally prototype has been developed and parameters are measure using network analyser. The observed results show that the proposed antenna structure can be used for wideband wireless communication applications with minimum loss and excellent radiation.

An RF Approach to Modelling Gallium Nitride Power Devices Using Parasitic Extraction

This paper begins with a comprehensive review into the existing GaN device models. Secondly, it identifies the need for a more accurate GaN switching model. A simple practical process based on radio frequency techniques using Vector Network Analyser is introduced in this paper as an original contribution. It was applied to extract the impedances of the GaN device to develop an efficient behavioural model. The switching behaviour of the model was validated using both simulation and real time double pulse test experiments at 500 V, 15 A conditions. The proposed model is much easier for power designers to handle, without the need for knowledge about the physics or geometry of the device. The proposed model for Transphorm GaN HEMT was found to be 95.2% more accurate when compared to the existing LT-Spice manufacturer model. This work additionally highlights the need to adopt established RF techniques into power electronics to reduce the learning curve while dealing with these novel high-speed switching devices.

Developments in GPR Based NDT for Ballastless Track of High-Speed Railways

For the past decades, ballastless track has been developed and used successfully throughout the world. Due to the multi-layer concrete structure of a ballastless track, timely detection of problems becomes a significant challenge. Ground Penetrating Radar (GPR), as an effective nondestructive method, has been applied to ballastless track in the last ten years. This paper reviews the state-of-the-art of GPR for the ballastless track. The challenges and problems are highlighted and discussed. A Vector Network Analyser (VNA) based stepped-frequency GPR system is considered for the problems and detection requirements. The experimental results show that the proposed system can detect narrow cracks in the depth up to 50cm.