Attentive visual tracking

The research reported here addresses the problem of detecting and tracking independently moving objects from a moving observer in real time, using corners as object tokens. Local image-plane constraints are employed to solve the correspondence problem removing the need for a 3D motion model. The approach relaxes the restrictive static-world assumption conventionally made, and is therefore capable of tracking independently moving and deformable objects. The technique is novel in that feature detection and tracking is restricted to areas likely to contain meaningful image structure. Feature instantiation regions are defined from a combination of odometry informatin and a limited knowledge of the operating scenario. The algorithms developed have been tested on real image sequences taken from typical driving scenarios. Preliminary experiments on a parallel (transputer) architecture indication that real-time operation is achievable.

Intelligent collision avoidance, control and guidance

This paper reviews a variety of advanced signal processing algorithms that have been developed at the University of Southampton as part of the Prometheus (Programme for European traffic flow with highest efficiency and unprecedented safety) programme to achieve an intelligent driver warning system (IDWS). The IDWS includes the detection of road edges, lanes, obstacles and their tracking and identification, estimates of time to collision, and behavioural modelling of drivers for a variety of scenarios. The underlying algorithms are briefly discussed in support of the IDWS.

A neurofuzzy approach to future intelligent driver support systems

This paper reviews a variety of advanced signal processing algorithms that have been developed at the University of Southampton as part of the Prometheus (PROgraMme for European Traffic flow with Highest Efficiency and Unprecedented Safety) research programme to achieve an intelligent driver warning system (IDWS). The IDWS includes: visual detection of both generic obstacles and other vehicles, together with their tracking and identification, estimates of time to collision and behavioural modelling of drivers for a variety of scenarios. These application areas are used to show the applicability of neurofuzzy techniques to the wide range of problems required to support an IDWS, and for future fully autonomous vehicles.

Rejected! The harmful effects of workgroup mistreatment and the moderating role of organisational norms

This program of research investigated the harmful effects of mistreatment by the workgroup, and the role of perceived rejection as a critical mediator linking mistreatment and outcomes. This research program had three primary purposes. First, the research aimed to examine the important role of workgroup mistreatment as an independent predictor of negative outcomes, over and above the influence of supervisor mistreatment. Second, the research aimed to examine the effect of perceived rejection as an explanatory variable linking workgroup mistreatment and outcomes. Finally, the moderating effect of organizational norms on the relationship between workgroup mistreatment and perceived rejection was examined. The relationships of interest were examined over four studies, using multiple methods of data collection, across part-time and full-time working samples. In Study 1 (Chapter 2), the independent role of workgroup mistreatment and the mediating role of perceived rejection were examined. One hundred and forty two part-time working participants took part in the study. The participants completed a questionnaire on workplace behaviors in their organizations. The results of hierarchical regression analyses revealed a strong harmful effect of workgroup mistreatment, independent of mistreatment by the supervisor. In addition, the results showed that perceived rejection fully mediated the relationship between workgroup mistreatment and depression and organizational based self esteem. The study highlighted that perceived rejection acts as a key underlying psychological mechanism involved in the effect of workgroup mistreatment. This study has been published in the Journal of Occupational Health Psychology. Study 2 and Study 3 were presented as one paper in Chapter 3. The aims of these two studies was to explore the effects of workgroup mistreatment on a wider range of individual and organizational level outcomes, and to provide further evidence of the mediating role of perceived rejection as observed in Study 1. The results from both studies demonstrated that workgroup mistreatment had a significant and independent role in predicting negative individual and organizational level outcomes, providing support for the findings of Study 1. In the first study, 189 participants received scenarios manipulating workgroup mistreatment and supervisor mistreatment. The results of hierarchical regression analyses revealed that workgroup mistreatment harmfully affected participants, over and above that of the supervisor. The results also demonstrated that perceived rejection mediated the positive relationships between workgroup mistreatment and depression and organizational deviance, and also the negative relationships between workgroup mistreatment and organizational based self esteem and organizational citizenship behaviors. The second study included an additional aim, to examine the moderating role of supportive organizational norms. Two hundred and twenty nine participants read scenarios that manipulated workgroup mistreatment, supervisor mistreatment and organizational norms. The results of hierarchical regression analyses revealed the significant harmful effects of workgroup mistreatment, over and above the influence of supervisor mistreatment. The results also revealed the mediating role of perceived rejection. The direct effect of positive organizational norms also emerged, consistent with previous research. In addition, the result revealed that employees who experienced supportive organizational norms were more likely to reconcile with their workgroup members after experiencing mistreatment compared to employees who experienced hostile organizational norms. Finally, an unexpected pattern on the key affective variables of depression and organizational based self esteem emerged, such that mistreatment led to more negative outcomes in the supportive norms condition than in the hostile condition, where employees appeared to be desensitized. This paper is currently under review at the Journal of Applied Social Psychology. In Study 4 (Chapter 4), the overall model of workplace mistreatment was tested on a sample of full-time workers in an applied setting. One hundred and seventy two adults took part in the study. Participants were required to evaluate their workplace regarding mistreatment and organizational norms and to report their own psychological, behavioral and organizational outcomes. The results revealed that workgroup mistreatment was associated with increased depression, stress and avoidance, over and above supervisor mistreatment. In addition, the results revealed that perceived rejection acted as an explanatory variable linking workgroup mistreatment to a number of outcomes. Furthermore, the moderating role of hostile organizational norms emerged on depression, stress, reconciliation and avoidance. This paper is currently under review at the Journal of Occupational Health Psychology. Overall, the four studies provided empirical support for the majority of the hypotheses. The effects were demonstrated for a range of psychological, behavioral, and organizational level outcomes, using multiple methods of data collection, across part-time and full-time workers. At the conclusion of the thesis (Chapter 5), an overall summary is provided of the findings across all four studies, practical and theoretical implications and research directions.

One step closer into the design of fall protective device for individuals fitted with a bone-anchored prosthesis

The consequences of falls are often dreadful for individuals with lower limb amputation using bone-anchored prosthesis.[1-5] Typically, the impact on the fixation is responsible for bending the intercutaneous piece that could lead to a complete breakage over time. .[3, 5-8] The surgical replacement of this piece is possible but complex and expensive. Clearly, there is a need for solid data enabling an evidence-based design of protective devices limiting impact forces and torsion applied during a fall. The impact on the fixation during an actual fall is obviously difficult to record during a scientific experiment.[6, 8-13] Consequently, Schwartze and colleagues opted for one of the next best options science has to offer: simulation with an able-bodied participant. They recorded body movements and knee impacts on the floor while mimicking several plausible falling scenarios. Then, they calculated the forces and moments that would be applied at four levels along the femur corresponding to amputation heights.[6, 8-11, 14-25] The overall forces applied during the falls were similar regardless of the amputation height indicating that the impact forces were simply translated along the femur. As expected, they showed that overall moments generally increased with amputation height due to changes in lever arm. This work demonstrates that devices preventing only against force overload do not require considering amputation height while those protecting against bending moments should. Another significant contribution is to provide, for the time, the magnitude of the impact load during different falls. This loading range is crucial to the overall design and, more precisely, the triggering threshold of protective devices. Unfortunately, the analysis of only a single able-bodied participant replicating falls limits greatly the generalisation of the findings. Nonetheless, this case study is an important milestone contributing to a better understanding of load impact during a fall. This new knowledge will improve the treatment, the safe ambulation and, ultimately, the quality of life of individuals fitted with bone-anchored prosthesis.

Barriers, drivers and enablers for transitioning towards innovation in the Australian water sector

The Australian water sector needs to adapt to effectively deal with the impacts of climate change on its systems. Challenges as a result of climate change include increasingly extreme occurrences of weather events including flooding and droughts (Pittock, 2011). In response to such challenges, the National Water Commission in Australia has identified the need for the water sector to transition towards being readily adaptable and able to respond to complex needs for a variety of supply and demand scenarios (National Water Commission, 2013). To successfully make this transition, the sector will need to move away from business as usual, and proactively pursue and adopt innovative approaches and technologies as a means to successfully address the impacts of climate change on the Australian water sector. In order to effectively respond to specific innovation challenges related to the sector, including climate change, it is first necessary to possess a foundational understanding about the key elements related to innovation in the sector. This paper presents this base level understanding, identifying the key barriers, drivers and enablers, and elements for innovative practise in the water sector. After initially inspecting the literature around the challenges stemming from climate change faced by the sector, the paper then examines the findings from the initial two rounds of a modified Delphi study, conducted with experts from the Australian water sector, including participants from research, government and industry backgrounds. The key barriers, drivers and enablers for innovation in the sector identified during the initial phase of the study formed the basis for the remainder of the investigation. Key elements investigated were: barriers – scepticism, regulation systems, inconsistent policy; drivers – influence of policy, resource scarcity, thought leadership; enablers – framing the problem, effective regulations, community acceptance. There is a convincing argument for the water sector transitioning to a more flexible, adaptive and responsive system in the face of challenges resulting from climate change. However, without first understanding the challenges and opportunities around making this transition, the likelihood of success is limited. For that reason, this paper takes the first step in understanding the elements surrounding innovation in the Australian water sector.

Melanoma cell colony expansion parameters revealed by approximate Bayesian computation

In vitro studies and mathematical models are now being widely used to study the underlying mechanisms driving the expansion of cell colonies. This can improve our understanding of cancer formation and progression. Although much progress has been made in terms of developing and analysing mathematical models, far less progress has been made in terms of understanding how to estimate model parameters using experimental in vitro image-based data. To address this issue, a new approximate Bayesian computation (ABC) algorithm is proposed to estimate key parameters governing the expansion of melanoma cell (MM127) colonies, including cell diffusivity, D, cell proliferation rate, λ, and cell-to-cell adhesion, q, in two experimental scenarios, namely with and without a chemical treatment to suppress cell proliferation. Even when little prior biological knowledge about the parameters is assumed, all parameters are precisely inferred with a small posterior coefficient of variation, approximately 2–12%. The ABC analyses reveal that the posterior distributions of D and q depend on the experimental elapsed time, whereas the posterior distribution of λ does not. The posterior mean values of D and q are in the ranges 226–268 µm2h−1, 311–351 µm2h−1 and 0.23–0.39, 0.32–0.61 for the experimental periods of 0–24 h and 24–48 h, respectively. Furthermore, we found that the posterior distribution of q also depends on the initial cell density, whereas the posterior distributions of D and λ do not. The ABC approach also enables information from the two experiments to be combined, resulting in greater precision for all estimates of D and λ.

A new constraint handling method for wind farm layout optimization with lands owned by different owners

For wind farm optimizations with lands belonging to different owners, the traditional penalty method is highly dependent on the type of wind farm land division. The application of the traditional method can be cumbersome if the divisions are complex. To overcome this disadvantage, a new method is proposed in this paper for the first time. Unlike the penalty method which requires the addition of penalizing term when evaluating the fitness function, it is achieved through repairing the infeasible solutions before fitness evaluation. To assess the effectiveness of the proposed method on the optimization of wind farm, the optimizing results of different methods are compared for three different types of wind farm division. Different wind scenarios are also incorporated during optimization which includes (i) constant wind speed and wind direction; (ii) various wind speed and wind direction, and; (iii) the more realisticWeibull distribution. Results show that the performance of the new method varies for different land plots in the tested cases. Nevertheless, it is found that optimum or at least close to optimum results can be obtained with sequential land plot study using the new method for all cases. It is concluded that satisfactory results can be achieved using the proposed method. In addition, it has the advantage of flexibility in managing the wind farm design, which not only frees users to define the penalty parameter but without limitations on the wind farm division.

Sectionalizing strategies for minimizing outage durations of critical loads in parallel power system restoration with bi-level programming

Fast restoration of critical loads and non-black-start generators can significantly reduce the economic losses caused by power system blackouts. In a parallel power system restoration scenario, the sectionalization of restoration subsystems plays a very important role in determining the pickup of critical loads before synchronization. Most existing research mainly focuses on the startup of non-black-start generators. The restoration of critical loads, especially the loads with cold load characteristics, has not yet been addressed in optimizing the subsystem divisions. As a result, sectionalized restoration subsystems cannot achieve the best coordination between the pickup of loads and the ramping of generators. In order to generate sectionalizing strategies considering the pickup of critical loads in parallel power system restoration scenarios, an optimization model considering power system constraints, the characteristics of the cold load pickup and the features of generator startup is proposed in this paper. A bi-level programming approach is employed to solve the proposed sectionalizing model. In the upper level the optimal sectionalizing problem for the restoration subsystems is addressed, while in the lower level the objective is to minimize the outage durations of critical loads. The proposed sectionalizing model has been validated by the New-England 39-bus system and the IEEE 118-bus system. Further comparisons with some existing methods are carried out as well.