3,12-Diaza-6,9-diazo­nia-2,13-dioxotetra­decane bis­(perchlorate)

The crystal structure of the title diprotonated diacetyl­triethyl­ene­tetra­mine (DAT) perchorate salt, C10H24N4O2 2+·2ClO4 −, can be described as a three-dimensional assembly of alternating layers consisting of diprotonated diacetyl­triethyl­ene­tetra­mine (H2DAT)2+ strands along [100] and the anionic species ClO4 −. The (H2DAT)2+ cations in the strands are connected via N—H⋯O hydrogen bonding between the acetyl groups and the amine groups of neighbouring (H2DAT)2+ cations. Layers of (H2DAT)2+ strands and perchlorate anions are connected by a network of hydrogen bonds between the NH and NH2 groups and the O atoms of the perchlorate anion. The asymmetric unit consits of one perchlorate anion in a general position, as well as of one cation that is located on a center of inversion

Understanding the potential of Self-Protection Jamming on board of miniature UAVs

Unarmed Aerial Vehicle (UAV) systems are very challenging targets due to their small size and ability to fly in low altitudes and speed. Particularly, in radar systems UAVs can exhibit similar radar cross section and Doppler parameters to clutter returns such as birds and trees. For this reason, often the micro-Doppler signature of the detected target is employed as discriminative characteristic. This work aims to examine micro-Doppler jamming solutions that could be implemented on board of miniature UAV platforms in order to deploy electronic countermeasures to radar sensors, with the aim to provide useful information to the radar community to counter these

SISAR imaging for space debris based on nanosatellites

The increasing amount of space debris poses a growing challenge in the development of space travel. In previous work, a proposed system comprising of a low budget space-borne passive radar based on CubeSAT, flying in Low Earth Orbit (LEO), demonstrated promising results in terms of space debris detection performance. In this work, a novel shadow inverse synthetic aperture radar (SISAR) model for space debris imaging based on nanosatellite is presented. An analysis of the received forward scattering signal is provided along with a novel model for moving transmitters and receivers SISAR imaging. Using simulated data and assuming different scenarios, the performance of the new algorithm is assessed; wherein, a classification scheme is applied using the output of the SISAR algorithm for classification between simple target shapes

Ambiguity function for distributed MIMO radar systems

In this paper a multi-static ambiguity function (AF) based on the Kullback directed divergence (KDD) and a distributed multiple-input and multiple-output radar system (DMRS) framework is introduced. Additionally a mathematical analysis is used to derive the AF in terms of signal-to-noise ratios (SNRs) and matched filter outputs. This method manages to extract an upper bound and properly define an AF bounded from 0 to 1. Moreover, this method leads in avoidance of large matrices inversions allowing less complex and more accurate computations. Finally the performance of the proposed method in localisation problems is assessed by comparing the proposed AF with the squared summation of the matched filter outputs at each receiver at different SNR scenarios

Interference mitigation for a joint radar communication system based on the FrFT for automotive applications

In multi user scenarios to prevent interference between users that share the same bandwidth at the same time,each user has to transmit wave forms that are uncorrelated with those of other users. However, due to spectrum limitations, the uncorrelated property cannot always be satisfied meaning that interference is unavoidable. In order to alleviate the interference, a framework for interference mitigation is presented. The performance of the proposed framework is tested on simulated and real signals. The real signal is acquired in a controlled laboratory environment using a Software Defined Radio (SDR). The simulated and experimental results show that the proposed framework is capable of mitigating the interference from other users

Interoperability Challenges in the Cybersecurity Information Sharing Ecosystem

Threat intelligence helps businesses and organisations make the right decisions in their fight against cyber threats, and strategically design their digital defences for an optimised and up-to-date security situation. Combined with advanced security analysis, threat intelligence helps reduce the time between the detection of an attack and its containment. This is achieved by continuously providing information, accompanied by data, on existing and emerging cyber threats and vulnerabilities affecting corporate networks. This paper addresses challenges that organisations are bound to face when they decide to invest in effective and interoperable cybersecurity information sharing and categorises them in a layered model. Based on this, it provides an evaluation of existing sources that share cybersecurity information. The aim of this research is to help organisations improve their cyber threat information exchange capabilities, to enhance their security posture and be more prepared against emerging threats

Edge Detection in SAR images using phase stretch transform

In this work a novel approach to edge detection on Synthetic Aperture Radar (SAR) images is introduced. The proposed method uses an optics inspired transform which emulates the diffraction of an image through a medium with nonlinear dispersive properties. The experimental results show that the output of the introduced Phase Stretch Transform (PST) in conjunction with further morphological operations can be effectively used for image edge detection

2-[Bis(2-amino­ethyl)amino]ethanaminium chloride dichloro­methane solvate

In the title compound, C6H19N4 +·Cl−·CH2Cl2, the non-H atoms of the ammonium ion show non-crystallographic C 3 symmetry. The chloride ion is embedded in a framework of seven crystallographically independent hydrogen bonds (five N—H⋯Cl and two C—H⋯Cl), which form layers parallel to the (100) plane. Two N---H...N bonds also occur