Human sound localisation cues and their relation to morphology

Binaural soundfield reproduction has the potential to create realistic threedimensional sound scenes using only a pair of normal headphones. Possible applications for binaural audio abound in, for example, the music, mobile communications and games industries. A problem exists, however, in that the head-related transfer functions (HRTFs) which inform our spatial perception of sound are affected by variations in human morphology, particularly in the shape of the external ear. It has been observed that HRTFs simply based on some kind of average head shape generally result in poor elevation perception, weak externalisation and spectrally distorted sound images. Hence, HRTFs are needed which accommodate these individual differences. Direct acoustic measurement and acoustic simulations based on morphological measurements are obvious means of obtaining individualised HRTFs, but both methods suffer from high cost and practical difficulties. The lack of a viable measurement method is currently hindering the widespread adoption of binaural technologies. There have been many attempts to estimate individualised HTRFs effectively and cheaply using easily obtainable morphological descriptors, but due to an inadequate understanding of the complex acoustic effects created in particular by the external ear, success has been limited. The work presented in this thesis strengthens current understanding in several ways and provides a promising route towards improved HRTF estimation. The way HRTFs vary as a function of direction is compared with localisation acuity to help pinpoint spectral features which contribute to spatial perception. 50 subjects have been scanned using magnetic resonance imaging to capture their head and pinna morphologies, and HRTFs for the same group have been measured acoustically. To make analysis of this extensive data tractable, and so reveal the mapping between the morphological and acoustic domains, a parametric method for efficiently describing head morphology has been developed. Finally, a novel technique, referred to as morphoacoustic perturbation analysis (MPA), is described. We demonstrate how MPA allows the morphological origin of a variety of HRTF spectral features to be identified

Command & Control: Understanding, Denying and Detecting - A review of malware C2 techniques, detection and defences

In this survey, we first briefly review the current state of cyber attacks, highlighting significant recent changes in how and why such attacks are performed. We then investigate the mechanics of malware command and control (C2) establishment: we provide a comprehensive review of the techniques used by attackers to set up such a channel and to hide its presence from the attacked parties and the security tools they use. We then switch to the defensive side of the problem, and review approaches that have been proposed for the detection and disruption of C2 channels. We also map such techniques to widely-adopted security controls, emphasizing gaps or limitations (and success stories) in current best practices.Comment: Work commissioned by CPNI, available at c2report.org. 38 pages. Listing abstract compressed from version appearing in repor

Camouflage covert communication in air by imitating cricket’s sound

When the radio communication of an armed squad fighting in a jungle is interfered with by enemy’s radio jamming equipment and their command and intelligence cannot be transmitted and exchanged, are there any other communication methods that can be used to solve such an emergency and covert communication problem? Focusing on this problem, a camouflage covert communication method (CCCM) in air is proposed by imitating cricket’s sound. As well-known, there exist all kinds of animals’ sounds in the jungle; however, hearing these animals’ sounds, people generally considers them as background noise and ignores them. Based on this fact, the proposed CCCM uses the cricket’s sound as the carrier wave, imitates the features of the cricket’s call sequence to construct the camouflage communication sequence, and utilizes the time interval (TI) between two adjacent pulses to encode information. Meanwhile, other animals’ sound is superimposed to the camouflage communication sequence to improve the camouflage ability of the generated communication sequence. Experimental results are provided to demonstrate the performance of the proposed CCCM

The Notion of Cyber Operations

The aim of this chapter, is to elaborate on the notion of ‘cyber operations’ as they seem to be used in a generic manner in popular media as well as in academics.This chapter differentiates for actors and motives, covering operations conducted by both state and non-state entities. Special attention will be paid to governmental cyber operations that are characterized by five distinct roles and paradigms: governance, protection, law enforcement, intelligence and military operations. In addition, governmental response mechanisms, based on the paradigms, are explained and operations themselves are operationalised