Human responses to demanding mental and physical work

Research into relationships between physiological activity and behaviour in humans has mainly considered performance at light work tasks. Furthermore, models of integrated activity have often been formulated around hypotheses of the arousal type, which were not particularly explicit about the interaction of the variables observed. [Continues.

Minimum-Fuel Low-Thrust Trajectory Optimization Via a Direct Adaptive Evolutionary Approach

Space missions with low-thrust propulsion systems are of appreciable interest to space agencies because of their practicality due to higher specific impulses. This research proposes a technique to the solution of minimum-fuel non-coplanar orbit transfer problem. A direct adaptive method via Fitness Landscape Analysis (FLA) is coupled with a constrained evolutionary technique to explore the solution space for designing low-thrust orbit transfer trajectories. Taking advantage of the solution for multi-impulse orbit transfer problem, and parameterization of thrust vector, the orbital maneuver is transformed into a constrained continuous optimization problem. A constrained Estimation of Distribution Algorithms (EDA) is utilized to discover optimal transfer trajectories, while maintaining feasibility of the solutions. The low-thrust trajectory optimization problem is characterized via three parameters, referred to as problem identifiers, and the dispersion metric is utilized for analyzing the complexity of the solution domain. Two adaptive operators including the kernel density and outlier detection distance threshold within the framework of the employed EDA are developed, which work based on the landscape feature of the orbit transfer problem. Simulations are proposed to validate the efficacy of the proposed methodology in comparison to the non-adaptive approach. Results indicate that the adaptive approach possesses more feasibility ratio and higher optimality of the obtained solutions.BEAZ Bizkaia, 3/12/DP/2021/00150; SPRI Group, Ekintzaile Program EK-00112-202

In-flight maintenance study Final report

Sample system analysis, MF requirements, redesign, and packaging desig

The Relationship Between Childhood Trauma, Person Beliefs and Trust in a Clinical Sample of People Experiencing Paranoia in Psychosis

The current thesis investigated two factors associated with psychosis; childhood trauma and person beliefs. Part one was a systematic review that quantitatively synthesised the existence of person beliefs in people with psychosis and at risk mental state (ARMS) compared to healthy controls, and the association of person beliefs with paranoia. More negative and less positive person evaluations were present in those with psychosis and ARMS, and negative person beliefs were consistently associated with paranoia. The greatest differences and associations were at the lower end of the psychosis continuum. A correlational meta-analysis for positive beliefs and paranoia could not be conducted due to the low number of studies available. The results are discussed in relation to models of persecutory delusions and help-seeking behaviour. Part two used an interactive virtual reality scene with a friendly avatar to examine the impact of childhood trauma and person evaluations on trust (trust appraisal and trusting behaviour). Twenty-two male participants with psychosis experiencing paranoia were recruited. Virtual reality was reported to be a safe and valid tool. Trust appraisal was predicted by childhood trauma exposure, symptom severity and positive other-evaluations, whilst positive self-beliefs predicted trusting behaviour. The implications for clinical work and research were discussed. Part three was a critical appraisal which reflected on the process of recruitment, the complexity of studying psychosis and trauma and methodological considerations from both parts of the thesis. This was a joint project with a fellow trainee, Kate Watchorn. Each thesis had a different focus and work was completed and presented separately

Using Prior Knowledge and Learning from Experience in Estimation of Distribution Algorithms

Estimation of distribution algorithms (EDAs) are stochastic optimization techniques that explore the space of potential solutions by building and sampling explicit probabilistic models of promising candidate solutions. One of the primary advantages of EDAs over many other stochastic optimization techniques is that after each run they leave behind a sequence of probabilistic models describing useful decompositions of the problem. This sequence of models can be seen as a roadmap of how the EDA solves the problem. While this roadmap holds a great deal of information about the problem, until recently this information has largely been ignored. My thesis is that it is possible to exploit this information to speed up problem solving in EDAs in a principled way. The main contribution of this dissertation will be to show that there are multiple ways to exploit this problem-specific knowledge. Most importantly, it can be done in a principled way such that these methods lead to substantial speedups without requiring parameter tuning or hand-inspection of models

Determinants of IS continuance: the use of mobile computing services by field service staff in a South African mandatory setting

M.Com (Information Systems) by Research 8/31/2015 Research report submitted to the University of Witwatersrand in fulfilment of the requirements for the degree of Master of Commerce (Information Systems)Rugged mobile computing devices have enhanced durability and protection, thus allowing these devices to be used in the field as opposed to the office. These rugged mobile computing devices provide organisations with the ability to extend their information system services to their field staff, such as delivery persons, transport drivers and field technicians. Bhattacherjee's (2001) IS continuance model appears to fall short in explaining IS continuance in the context of field service staff who often perform repetitive tasks as part of their job as opposed to doing more complex tasks as performed by office bound knowledge workers. An IS continuance-based study in a South African organisation, where field service staff use rugged mobile devices, will improve our understanding of user behaviour towards technology within the body of IS knowledge. This study makes a contribution to theory by demonstrating that the core IS Continuance model by Bhattacherjee (2001), can be extended to include additional constructs to better predict IS continuance. This study proposes and tests an extension of Bhattacherjee’s (2001) IS continuance model, which explains the determinants of IS continuance intention in terms of affective and cognitive factors. The cognitive factors are task technology fit, perceived service availability, result demonstrability and the affective factor is the construct of familiarity. The study is carried out in a mandatory setting within the context of field technicians (working for a South African utility organisation) using application services on rugged mobile devices. To date, most IS continuance studies appear to have been carried out in a voluntary setting or an academic institution setting and very few of them have been conducted in organisations (mandatory settings). A structured questionnaire with closed questions was developed to capture field data from 144 participants on each of the study’s variables The hypotheses were tested using both parametric and non-parametric correlation and regression statistical analyses. The independent variables of perceived post-usage usefulness, familiarity and satisfaction explain approximately 51% of the variance in IS continuance intention. One of the key findings of the research is that perceived post usage usefulness loses its significance in the presence of Familiarity in predicting IS continuance intention. Thus, familiarity (affective factor) is the stronger predictor of IS continuance intention as opposed to the cognitive factors. In summary, this study showed that the affective factor is a stronger predictor of IS continuance intention than the cognitive factors, thus providing a richer understanding of IS continuance and a foundation for future research. Thus, in addition to methodological and contextual contributions, this study also contributes to theory

Summary report on work package 3 "Types of Factors"

This summary report presents the main results of Work Package 3 "Types of Factors" of the TRACE Project. The work as performed in the tasks 3.1 (accident related factors), 3.2 (sociological and cultural factors), 3.3 (trip-related factors), and 3.4 (driving-task associated factors) and presented in the Deliverables 3.1 to 3.4 and an additional internal TRACE Report (Collection of Sub-Reports for task 3.3) is summarized and discussed. The objective of defining relevant accident related factors first and the objective of analysing traffic accident causation - from a factor's point of view while taking traditional views into account - on different levels - by using statistic methods for existing databases as provided by the Work Package 3 Partners and - by using new (developed in Work Package 5 of the TRACE project) methods on new case analysis in order to gain new knowledge on accident causation was possible to reach. The scope of the identified key aspects as found by the Partners in their work for the relevance in EU27 is discussed. In accordance, even further, appropriate suggestions for prevention of traffic accidents can be derived

Investigation Into the Physical Environmental Correlates of Aggressive Behaviour in Children with Neurodevelopmental Disorders (NDDs)

Background: Physical environmental influences on childhood aggression in children with neurodevelopmental disabilities is a severely under-researched research locus. The aim of this doctorate was to elucidate specific associations between children’s developmental environment and aggressive behaviours, using this evidence to reciprocally inform an experimental psychology project to investigate underlying mechanisms. To explore these effects, the programme of study was broadly divided into three reflexive workstreams using diverse research methodologies. Methods: In the first workstream, I conducted a systematic review of the current literature examining physical environmental influences on childhood aggressive behaviours in both typically developing children (aged 0 – 18) and those diagnosed with NDDs. The literature on children with NDDs was substantially limited in comparison to peers without NDDs. The second workstream was comprised of a large-scale secondary data analysis (multiply imputed growth curve modelling) to investigate environmental influences on conduct problems across early development. I used data from the Millennium Cohort Study (MCS) to assess how physical environmental metrics, such as neighbourhood greenspace, air pollution, household crowding, and presence of home damp influenced the development and severity of conduct problems in children with (n=8013) and without NDDs (n=155) between the ages of 3 – 11 years. Finally, building upon evidence from the previous two workstreams, I designed a proof-of-principle psychological experiment to examine the influence of urban nature exposure on children with NDDs. Specifically, simulating a real-world urban greenspace using a Person-Environment-Activity Research Laboratory (PEARL). This facilitated the ability to manipulate and isolate individual environmental aspects of urban nature exposure (light, sound, and projection). Following ethical review and approval, I recruited 3 children (100% male) with mild and moderate intellectual disability aged between 12 – 15 years (Mean age = 14) attending a local school for children with special educational needs. We examined their physiological reactions to four simulated urban green space aspects (light, sound, landscape projections, and vegetation) against a baseline control condition. I also collected demographic information on parent reported aggressive behaviours, exposure to local greenspace(s), physical and mental health history, medication, and adaptive behaviours (ABAS-3). This research lays the foundation for future large scale experimental paradigms that can disentangle the effects of nature exposure in these children, with the aim of translating these findings into real world therapeutic design interventions and relevant policy changes to improve the quality of the built environment for these children. Findings: From articles retrieved from my systematic review I found evidence for the beneficial influences of nature in both populations, and simultaneously negative effects of both noise and air pollution in typically developing children only. Evidence for other environmental aspects such as crowding, music, urbanicity, meteorology, and interior design had either insufficient or inconsistent evidence to extrapolate concreate conclusions. More evidence on the effect of these exposures on child aggression outcomes is recommended. From the analysis of the MCS cohort I found various sociodemographic factors (ethnicity, sex, poverty, family structure, maternal distress) and internal residential conditions were associated with increased childhood conduct problem trajectories in both groups of children. I also discovered potential evidence of a moderating influence effect of intellectual disability on the relationship between spatial density and conduct problems. From the final experimental project, I report preliminary evidence for the influence of urban greenspaces to reduce physiological arousal in children with complex neurodisability profiles. Initial evidence for the hierarchical nature of urban greenspace sensorial aspects was reported, for example: that urban nature soundscapes maybe a more influential environmental stimuli than lighting or landscape projections. Conclusion: Drawing together multi-disciplinary research methodologies facilitated the ability to identify disparities in research examining physical environmental determinants of aggression in neurodiverse child populations. Reciprocally, the systematic review and secondary data analysis contributed incrementally to filling this lacuna of research. Using findings from these two work streams, I identified that exploring the potentially therapeutic influences of urban nature exposure on children with neurodevelopmental disorders may provide novel indicators of its aetiological mechanisms. I reported original findings supporting these research aims, elucidating the potential hierarchical nature of urban greenspace elements. This was also the first study of its kind reporting the potential for simulated urban park spaces to reduce physiological arousal in neurodivergent children with aggressive behavioural difficulties