Selective removal of organics for water reclamation

Electrolysis has been investigated as a means of purifying waste water. The feasibility of the direct electrochemical oxidation of urea has been demonstrated. Urea levels were reduced from 1200 ppm to 1 ppm forming the basis for a new approach to urine purification where the only consumable is electrical energy. Preliminary estimates of the energy requirements are 270 W/hr per liter of urine. Urea oxidation rates of around 350 mg urea/hr/m2 were observed. It is anticipated that a 1 m2 geometric area of electrode could treat urine for a crew of several persons. The low levels of organic contaminants resulting from this treatment indicate that the approach may have an impact as a post treatment process. Experiments are planned to investigate this later possibility

Fine Scale Structure in Cometary Dust Tails

Cometary dust tails often contain particularly striking fine structure. Unexplained alone by bulk dust properties, features such as the highly notable striae form due to as-yet unconstrained processes. This fine structure appears to be quite dynamic around perihelion, with little in the way of literature fully explaining what, how or why. This thesis focuses on the creation of this fine structure and its temporal evo- lution close to the sun. It shows the importance of the local conditions in the solar wind in explaining the behaviour of dust in a region of the heliosphere only recently probed by in-situ missions. To enable this analysis, a new technique has been developed – temporal map- ping – that displays cometary dust tails directly in the radiation beta (ratio of radi- ation pressure to gravity) and dust ejection time phase space. This allows for the combination of data sets and the removal of transient motion and scaling effects. The analysis makes use of serendipitous data from the SOHO and STEREO solar missions, and focuses on three comets, C/2006 P1 McNaught, C/2011 L4 Pan-STARRS and C/2002 V1 NEAT. At C/2006 P1, striae formation is directly shown through temporal mapping; the first observations of striae forming at any comet. A period of morphological change where striae undergo a reorganisation is also displayed and attributed to Lorentz forces caused by the comet’s dust tail crossing the heliospheric current sheet. The study of C/2011 L4 also reveals a period of striae reorganisation also cor- related with heliospheric current sheet crossings. Reorganised striae at both C/2006 P1 and C/2011 L4 display alignments that may be compatible with an additional solar wind influence. C/2002 V1 shows an interaction where a coronal mass ejection appears to affect dust tail orientation. The possibility of high solar wind pressure affecting dust morphology is ruled out. Changes in tail structure would therefore seem to be caused by Lorentz force effects

Its Not All About the Money: Self-efficacy and Motivation in Defensive and Offensive Cyber Security Professionals

Two important factors that define how humans go about performing tasks are self-efficacy and motivation. Through a better understanding of these factors, and how they are displayed by professionals in different roles within the cyber security discipline we can start to explore better ways to exploit the human capability within our cyber security. From our study of 137 cyber security professionals we found that those in attack-focussed roles displayed significantly higher-levels of self-efficacy than those in defensive-focussed roles. We also found those in attack-focussed roles demonstrated significantly higher levels of intrinsic motivation and significantly lower levels of externally regulated motivation. It should be noted we found no correlation with age or experience with either the focus of the practitioners task (whether offensive or defensive focussed) or their levels of motivation or self-efficacy. These striking findings further highlight the differences between those performing tasks that are self-described as offensive and those that are self-described as defensive. This also demonstrates the asymmetry that has long existed in cyber security from both a technical and opportunity viewpoint also exists in the human dimension

Reconstructing what you said: Text Inference using Smartphone Motion

Smartphones and tablets are becoming ubiquitous within our connected lives and as a result these devices are increasingly being used for more and more sensitive applications, such as banking. The security of the information within these sensitive applications is managed through a variety of different processes, all of which minimise the exposure of this sensitive information to other potentially malicious applications. This paper documents experiments with the 'zero-permission' motion sensors on the device as a side-channel for inferring the text typed into a sensitive application. These sensors are freely accessible without the phone user having to give permission. The research was able to, on average, identify nearly 30 percent of typed bigrams from unseen words, using a very small volume of training data, which was less than the size of a tweet. Given the natural redundancy in language this performance is often enough to understand the phrase being typed. We found that large devices were typically more vulnerable, as were users who held the device in one hand whilst typing with fingers. Of those bigrams which were not correctly identified over 60 percent of the errors involved the space bar and nearly half of the errors are within two keys on the keyboard

Principal Component Analysis and Radiative Transfer modelling of Spitzer IRS Spectra of Ultra Luminous Infrared Galaxies

The mid-infrared spectra of ultraluminous infrared galaxies (ULIRGs) contain a variety of spectral features that can be used as diagnostics to characterise the spectra. However, such diagnostics are biased by our prior prejudices on the origin of the features. Moreover, by using only part of the spectrum they do not utilise the full information content of the spectra. Blind statistical techniques such as principal component analysis (PCA) consider the whole spectrum, find correlated features and separate them out into distinct components. We further investigate the principal components (PCs) of ULIRGs derived in Wang et al.(2011). We quantitatively show that five PCs is optimal for describing the IRS spectra. These five components (PC1-PC5) and the mean spectrum provide a template basis set that reproduces spectra of all z<0.35 ULIRGs within the noise. For comparison, the spectra are also modelled with a combination of radiative transfer models of both starbursts and the dusty torus surrounding active galactic nuclei. The five PCs typically provide better fits than the models. We argue that the radiative transfer models require a colder dust component and have difficulty in modelling strong PAH features. Aided by the models we also interpret the physical processes that the principal components represent. The third principal component is shown to indicate the nature of the dominant power source, while PC1 is related to the inclination of the AGN torus. Finally, we use the 5 PCs to define a new classification scheme using 5D Gaussian mixtures modelling and trained on widely used optical classifications. The five PCs, average spectra for the four classifications and the code to classify objects are made available at: http://www.phys.susx.ac.uk/~pdh21/PCA/Comment: 11 pages, 12 figures, accepted for publication in MNRA

Deconstructing who you play: character choice in online gaming

The major growth in gaming over the last five to ten years has been through the expansion in online gaming, with the most frequent gamers now playing more games online than with others in person. The increase in cooperative multiplayer online gaming, where players who do not know each other come together in teams to achieve a common goal, leads to interesting social situations. The research in this paper is focussed on the online multiplayer game Overwatch, in this game playable characters are grouped into a number of classes and characters within these classes. A player chooses the character at the start of a given round, and whilst they can change the character during the game round this is generally undesirable. In this research we were interested in how players go about selecting a character for a given round of the game, this is a complex interaction where a player has to balance between personal character preference (either a character they enjoy playing or is well-mapped to their playstyle and skill) and ensuring a team has a balance of player classes. The interaction is complicated by the online nature meaning it is difficult to reward a team-mate for selecting a character they may not wish to play or playing a character which may mean they will perform poorly but the team will win. We recruited over 1000 Overwatch players and surveyed them on how they make their character choices within the game, they were also asked to complete various psychometric tests. We found that a gamers player ‘type’ (i.e. Killer, Achiever, Explorer or Socialiser) was defined by their agreeableness and their gender. We also found that player’s choice of character class was related to their level of agreeableness and extroversion modulated by the player’s gender. We also found that those who rate highly in conscientiousness and agreeableness and are socialisers or achievers were more likely to choose a character in order to achieve a balanced team rather than personal preference. The research is unique in the scale and number of respondents, it also addresses a problem in co-operative gaming where players must negotiate the composition of a team. This negotiation is often performed without any background knowledge of other player’s skill levels, this is the first study at this scale considering this within the context of co-operative online gaming

Delensing CMB Polarization with External Datasets

One of the primary scientific targets of current and future CMB polarization experiments is the search for a stochastic background of gravity waves in the early universe. As instrumental sensitivity improves, the limiting factor will eventually be B-mode power generated by gravitational lensing, which can be removed through use of so-called delensing algorithms. We forecast prospects for delensing using lensing maps which are obtained externally to CMB polarization: either from large-scale structure observations, or from high-resolution maps of CMB temperature. We conclude that the forecasts in either case are not encouraging, and that significantly delensing large-scale CMB polarization requires high-resolution polarization maps with sufficient sensitivity to measure the lensing B-mode. We also present a simple formalism for including delensing in CMB forecasts which is computationally fast and agrees well with Monte Carlos.Comment: typos correcte

Chemical nonlinearities in relating intercontinental ozone pollution to anthropogenic emissions

Model studies typically estimate intercontinental influence on surface ozone by perturbing emissions from a source continent and diagnosing the ozone response in the receptor continent. Since the response to perturbations is non-linear due to chemistry, conclusions drawn from different studies may depend on the magnitude of the applied perturbation. We investigate this issue for intercontinental transport between North America, Europe, and Asia with sensitivity simulations in three global chemical transport models. In each region, we decrease anthropogenic emissions of NOx and nonmethane volatile organic compounds (NMVOCs) by 20% and 100%. We find strong nonlinearity in the response to NOx perturbations outside summer, reflecting transitions in the chemical regime for ozone production. In contrast, we find no significant nonlinearity to NOx perturbations in summer or to NMVOC perturbations year-round. The relative benefit of decreasing NOx vs. NMVOC from current levels to abate intercontinental pollution increases with the magnitude of emission reductions