The influence of organisational typology, strategy, leadership and psychological forces on UK offshore oil and gas industry safety performance.

The UK Offshore Oil and Gas Industry is recognised as having made significant safety performance improvement progress, following the Piper Alpha disaster (6th July 1988), subsequent Public Inquiry and 106 recommendations made by the Cullen Report. However, accidents continue to occur on offshore assets due to leadership and organisational failures, poor behaviours, lack of operating discipline, asset integrity challenges and an absence of aligned safety strategy. Research was conducted through a strategic lens, looking across a typical operator company's value chain, and going beyond the predominant technical and engineering safety focus. Utilising safety climate as a leading indicator of safety performance, research explored the ways in which organisational typology, strategy, leadership and psychological forces contribute to safety performance on offshore assets. Research of this nature had not previously been conducted in the UK offshore oil and gas industry - triangulation of qualitative and quantitative data was utilised. Semi-structured interviews were conducted onshore with managers and supervisors to determine the organisational typology make-up of the value chain and associated safety strategy, with consideration for leadership and the psychological forces dynamic of human factors. An offshore workforce safety study was deployed at seven offshore assets. Under academic licence, the study utilised proven and validated data collection tools: authentic leadership questionnaire (ALQ); psychological capital questionnaire (PCQ); and the safety climate tool (SCT). The research identified organisational typology patterns across the value chain. Operator and contractor organisations were determined to typically identify as defenders and prospectors, while sub-contractors identified as analyzers and reactors. Considering safety performance at the offshore assets as measured by safety climate perception, it was concluded that organisational typology had no influence. There was no statistically significant difference between the safety performance indicator of safety climate perceptions across the typologies associated with the operator, contractor and sub-contractor value chain groups. Strict compliance with the operator control of work arrangements plus consistent operator safety messaging was concluded to be the mediating factor. Authentic leadership and psychological capital constructs were both demonstrated to be positively correlated with safety climate scores. Each of the seven assets studied returned 'Good' safety climate scores on a validated scoring system. However, there was no significant difference determined across operator, contractor and sub-contractor groups for safety climate scores by authentic leadership and psychological capital. Strict compliance with the operator control of work arrangements plus consistent operator safety messaging was again concluded to be the mediating factor. Persisting with current compliance-based practices was determined to possess a limiting effect over the ability to evolve from 'Good' to 'Excellent' safety climate scores in future offshore asset operations. Contributions to practice, knowledge and method were derived from the research findings and conclusion. Four specific recommendations were made for practice, plus four for future safety science research

Investigating the modulation of cognition and event-related potentials relating to visual attention, working memory, and executive control in habitual videogame players

The overall objective of this thesis was to produce a document that investigated whether habitual videogame playing modulated cognitive processes related to visual processing and where in the processing stream these modulations occur. In this thesis, the term ‘cognitive modulation’ refers to any neurological differences (as identified through ERP) between videogame players and non-videogame players that theoretically may have been a result of videogame playing. Using this method, I am able to ascertain whether differences between the two groups are observed in early sensory ERPs, in which case VGPs might possess an advantage in bottom-up visual processing, later selective attention which might indicate alterations in top-down attentional processing, motor-response waveforms that may indicate difference in stimulus response mappings, and finally any differences in working memory capacity that might be the underlying cause of supposed attentional differences. An example of cognitive modulation was observed by Wu et al., (2012) and discussed in more detail in the introduction of this thesis. Indeed these modulations should also be accompanied by a behavioural difference between the two groups. As ERP was the primary source of neurophysiological recordings in this thesis, modulations could occur in the amplitude, mean activity, or peak latency of ERP waveforms.The paradigms employed in this thesis were chosen and designed so that in combination they provide a measure of potential cognitive modulation across the entire processing stream. That is, from early sensory ERPs, through selective attentional ERPs, including executive control ERPs and concluding at ERPs related to motor response priming. As these studies primarily focused on attentional processes, an ERP chapter towards the end of this thesis was included to identify whether any modulations in attentional ERPs were an indirect result of modulated working memory.Chapters 2 and 3 in this thesis focus on attentional control, resources, and the inhibitory processes of attention. Specifically, these chapters related to the attentional control each group employed when being presented with distracting items. Indeed, I observed modulated cognitive processes in chapter 3 related inhibitory processing in both attention and executive control related processes. In addition to this, the flanker task in Chapter 3 also allowed me to measure and modulation in motor priming between videogame players and non-videogame players.Chapters 4 and 5 looked more closely at ERPs related to selective attention such as the N2pc and P3, alongside early sensory ERPs (N1, P1, etc.). In response to observing differences in how each group processed distractors (related to the N2pc in Chapter 4), Chapter 5 employed a very specific test in order to split the N2pc into its component parts to further investigate whether any cognitive modulation between groups was a result of altered priority on processing targets or inhibiting distractors.Chapter 6 in this thesis sought to identify whether any differences observed in the attentional processing stream was actually the result of modulations in working memory, a cognitive process theoretically closely related to selective attention. Chapter 6 measured the contralateral delay activity, a neurological waveform that correlates with items held in visual working memory.Chapter 7 provided further exploratory psychophysical testing to identify whether any potential behavioural between-group differences extend beyond the usual visual field our groups would play videogames in. This involved testing the crowding phenomenon whereby participants are unable to identify a stimulus when closely flanked by distractors.This these concludes with Chapter 8, an overall discussion of each chapters results and how these theoretically synthesise with one another in relation to the two objectives of this thesis; does videogame playing modulate cognitive, and where in the attentional processing stream does this occur

How robust are reconstruction thresholds for community detection?

The stochastic block model is one of the oldest and most ubiquitous models for studying clustering and community detection. In an exciting sequence of developments, motivated by deep but non-rigorous ideas from statistical physics, Decelle et al. conjectured a sharp threshold for when community detection is possible in the sparse regime. Mossel, Neeman and Sly and Massoulié proved the conjecture and gave matching algorithms and lower bounds. Here we revisit the stochastic block model from the perspective of semirandom models where we allow an adversary to make 'helpful' changes that strengthen ties within each community and break ties between them. We show a surprising result that these 'helpful' changes can shift the information-theoretic threshold, making the community detection problem strictly harder. We complement this by showing that an algorithm based on semidefinite programming (which was known to get close to the threshold) continues to work in the semirandom model (even for partial recovery). This suggests that algorithms based on semidefinite programming are robust in ways that any algorithm meeting the information-theoretic threshold cannot be. These results point to an interesting new direction: Can we find robust, semirandom analogues to some of the classical, average-case thresholds in statistics? We also explore this question in the broadcast tree model, and we show that the viewpoint of semirandom models can help explain why some algorithms are preferred to others in practice, in spite of the gaps in their statistical performance on random models.National Science Foundation (U.S.). Faculty Early Career Development Program (Award CCF-1453261)Google Faculty Research AwardNihon Denki Kabushiki Kaish

An electron Talbot interferometer

The Talbot effect, in which a wave imprinted with transverse periodicity reconstructs itself at regular intervals, is a diffraction phenomenon that occurs in many physical systems. Here we present the first observation of the Talbot effect for electron de Broglie waves behind a nanofabricated transmission grating. This was thought to be difficult because of Coulomb interactions between electrons and nanostructure gratings, yet we were able to map out the entire near-field interference pattern, the "Talbot carpet", behind a grating. We did this using a Talbot interferometer, in which Talbot interference fringes from one grating are moire'-filtered by a 2nd grating. This arrangement has served for optical, X-ray, and atom interferometry, but never before for electrons. Talbot interferometers are particularly sensitive to distortions of the incident wavefronts, and to illustrate this we used our Talbot interferometer to measure the wavefront curvature of a weakly focused electron beam. Here we report how this wavefront curvature demagnified the Talbot revivals, and we discuss applications for electron Talbot interferometers.Comment: 5 pages, 5 figures, updated version with abstrac

Human Interpretation of Trade-Off Diagrams in Multi-Objective Problems: Implications for Developing Interactive Decision Support Systems

The growing need for efficient and effective human decision-makers warrants a better understanding of how decision support systems (DSS) guide users to improved decisions. Decision support approaches utilize visual aids to assist decision-making, including trade-off diagrams. These visualizations help comprehension of key trade-offs among decision alternatives. However, little is known about the role of trade-off diagrams in human decision-making and the best way to present them. Here, we discuss an empirical study with two goals: 1) evaluating DSS interactivity and 2) identifying decision-making strategies with trade-off diagrams. We specifically investigate the value of interface interactivity and problem context as users make nine increasingly complex decisions. Our results suggest that problem context and interactivity separately influence ability to navigate trade-off diagrams

Wave-induced loss of ultra-relativistic electrons in the Van Allen radiation belts.

The dipole configuration of the Earth's magnetic field allows for the trapping of highly energetic particles, which form the radiation belts. Although significant advances have been made in understanding the acceleration mechanisms in the radiation belts, the loss processes remain poorly understood. Unique observations on 17 January 2013 provide detailed information throughout the belts on the energy spectrum and pitch angle (angle between the velocity of a particle and the magnetic field) distribution of electrons up to ultra-relativistic energies. Here we show that although relativistic electrons are enhanced, ultra-relativistic electrons become depleted and distributions of particles show very clear telltale signatures of electromagnetic ion cyclotron wave-induced loss. Comparisons between observations and modelling of the evolution of the electron flux and pitch angle show that electromagnetic ion cyclotron waves provide the dominant loss mechanism at ultra-relativistic energies and produce a profound dropout of the ultra-relativistic radiation belt fluxes

Skill assessment of models relevant for the implementation of ecosystem-based fisheries management

The advance of ecosystem-based fisheries management worldwide has made scientific advice on fisheries related questions more complex. However, despite the need to take interactions between fish stocks, and between stocks and their environment into account, multispecies and ecosystem models are still hardly used as a basis for fishery advice. Although reasons are numerous, the lack of high-level guidance for target-oriented skill assessments of such models contributes to the mistrust to use such models for advice. In this study, we propose a framework of guiding questions for a pragmatic and target-oriented skill assessment. The framework is relevant for all models irrespective of their complexity and approach. It starts with general questions on the advice purpose itself, the type of model(s) and data available for performance testing. After this, the credibility of the hindcasts are evaluated. A special emphasis is finally put on testing predictive skills. The skill assessment framework proposed provides a tool to evaluate a model's suitability for the purpose of providing specific advice and aims to avoid the bad practice of incomplete skill assessments. In the case of multiple models available, it can facilitate the evaluation or choosing of the best model(s) for a given advice product and intends to ensure a level playing field between models of different complexities. The suite of questions proposed is an important step to improve the quality of advice products for a successful implementation of ecosystem-based fisheries management