An optimal control approach to testing theories of human information processing constraints

This thesis is concerned with explaining human control and decision making behaviours in an integrated framework. The framework provides a means of explaining human behaviour in terms of adaptation to the constraints imposed by both the task environment and the information processing mechanisms of the mind. Some previous approaches tended to have been polarised between those that have focused on rational analyses of the task environment, on the one hand, and those that have focused on the mechanisms that give rise to cognition on the other hand. The former usually is based on the assumption that rational human beings adapt to the external environment by achieving 'goals' defined only by the task environment and with minimal consideration of the mechanisms of the human mind; while the latter focuses on information processing mechanisms that are hypothesised to generate behaviour, e.g., heuristics, or rules. In contrast, in the approach explored in this thesis, mechanism and rationality are tightly integrated. This thesis investigates a $state$ $estimation$ $and$ $optimal$ $control$ approach, in which human behavioural strategies and heuristics, rather than being programmed into the model, emerge as a consequence of rational adaptation given a theory of the information processing constraints

A STUDY ON STRUCTURAL, VISCOELASTIC PROPERTY AND OSTEOBLAST CHANGES IN OSTEOLYTIC METASTASES

Ph.DDOCTOR OF PHILOSOPH

Highly Sensitive Surface-Enhanced Raman Scattering Sensing of Heparin Based on Antiaggregation of Functionalized Silver Nanoparticles

We report a simple and sensitive surface-enhanced Raman scattering (SERS) platform for the detection of heparin, based on antiaggregation of 4-mercaptopyridine (4-MPY) functionalized silver nanoparticles (Ag NPs). Here, protamine was employed as a medium for inducing the aggregation of negatively charged 4-MPY functionalized Ag NPs through surface electrostatic interaction, which resulted in significantly enhanced Raman signal of the Raman reporter. However, in the presence of heparin, the interaction between heparin and protamine decreased the concentration of free protamine, which dissipated the aggregated 4-MPY functionalized Ag NPs and thus decreased Raman enhancement effect. The degree of aggregation and Raman enhancement effect was proportional to the concentration of added heparin. Under optimized assay conditions, good linear relationship was obtained over the range of 0.5-150 ng/mL (R-2 = 0.998) with a minimum detectable concentration of 0.5 ng/mL in standard aqueous solution. Furthermore, the developed method was also successfully applied for detecting heparin in fetal bovine serum samples with a linear range of 1-400 ng/mL.We report a simple and sensitive surface-enhanced Raman scattering (SERS) platform for the detection of heparin, based on antiaggregation of 4-mercaptopyridine (4-MPY) functionalized silver nanoparticles (Ag NPs). Here, protamine was employed as a medium for inducing the aggregation of negatively charged 4-MPY functionalized Ag NPs through surface electrostatic interaction, which resulted in significantly enhanced Raman signal of the Raman reporter. However, in the presence of heparin, the interaction between heparin and protamine decreased the concentration of free protamine, which dissipated the aggregated 4-MPY functionalized Ag NPs and thus decreased Raman enhancement effect. The degree of aggregation and Raman enhancement effect was proportional to the concentration of added heparin. Under optimized assay conditions, good linear relationship was obtained over the range of 0.5-150 ng/mL (R-2 = 0.998) with a minimum detectable concentration of 0.5 ng/mL in standard aqueous solution. Furthermore, the developed method was also successfully applied for detecting heparin in fetal bovine serum samples with a linear range of 1-400 ng/mL

The dissociable effects of reward on sequential motor behavior

Reward has consistently been shown to enhance motor behavior; however, its beneficial effects appear to be largely unspecific. For example, reward is associated with both rapid and training-dependent improvements in performance, with a mechanistic account of these effects currently lacking. Here we tested the hypothesis that these distinct reward-based improvements are driven by dissociable reward types: monetary incentive and performance feedback. Whereas performance feedback provides information on how well a motor task has been completed (knowledge of performance), monetary incentive increases the motivation to perform optimally without providing a performance-based learning signal. Experiment 1 showed that groups who received monetary incentive rapidly improved movement times (MTs), using a novel sequential reaching task. In contrast, only groups with correct performance-based feedback showed learning-related improvements. Importantly, pairing both maximized MT performance gains and accelerated movement fusion. Fusion describes an optimization process during which neighboring sequential movements blend together to form singular actions. Results from experiment 2 served as a replication and showed that fusion led to enhanced performance speed while also improving movement efficiency through increased smoothness. Finally, experiment 3 showed that these improvements in performance persist for 24 h even without reward availability. This highlights the dissociable impact of monetary incentive and performance feedback, with their combination maximizing performance gains and leading to stable improvements in the speed and efficiency of sequential actions. NEW & NOTEWORTHY Our work provides a mechanistic framework for how reward influences motor behavior. Specifically, we show that rapid improvements in speed and accuracy are driven by reward presented in the form of money, whereas knowledge of performance through performance feedback leads to training-based improvements. Importantly, combining both maximized performance gains and led to improvements in movement quality through fusion, which describes an optimization process during which sequential movements blend into a single action

Study on Effect of Product Liability to Inherent Safety

AbstractMany industry accidents and product liability problems occur in China in recent years. The safety of products not only influents public daily life, also affects industrial production. Product safety concept reflects the attitude of people to product safety, and is reflected in product liability system. The influences of different product liability system to the status of inherent safety were studied based on the analysis of the doctrine of liability fixation in different technology development period. It can be seen that there were still many problems in the product liability acts such as the standard and identification of product defects, compensation liability, which were not beneficial to improve the industry safety though strict liability has been accepted in our country. Therefore, product liability system should be improved, and the method of design defect determination should be established. At the same time, carrying out the risk evaluation of the products, increasing the amount and scope of compensation are also important to realize the product safety and industrial inherent safety