Multisegmented optimal trajectories

Bolza problem of calculus of variations in terms of control coding applied to trajectorie

The case of muddled units in temporal discounting

While parameters are crucial components of cognitive models, relatively little importance has been given to their units. We show that this has lead to some parameters to be contaminated, introducing an artifactual correlation between them. We also show that this has led to the illegal comparison of parameters with different units of measurement – this may invalidate parameter comparisons across participants, conditions, groups, or studies. We demonstrate that this problem affects two related models: Stevens' power law and Rachlin's delay discounting model. We show that it may even affect models which superficially avoid the incompatible units problem, such as hyperbolic discounting. We present simulation results to demonstrate the extent of the issues caused by the muddled units problem. We offer solutions in order to avoid the problem in the future or to aid in re-interpreting existing datasets

hp-adaptive discontinuous Galerkin solver for elliptic equations in numerical relativity

A considerable amount of attention has been given to discontinuous Galerkin methods for hyperbolic problems in numerical relativity, showing potential advantages of the methods in dealing with hydrodynamical shocks and other discontinuities. This paper investigates discontinuous Galerkin methods for the solution of elliptic problems in numerical relativity. We present a novel hp-adaptive numerical scheme for curvilinear and non-conforming meshes. It uses a multigrid preconditioner with a Chebyshev or Schwarz smoother to create a very scalable discontinuous Galerkin code on generic domains. The code employs compactification to move the outer boundary near spatial infinity. We explore the properties of the code on some test problems, including one mimicking Neutron stars with phase transitions. We also apply it to construct initial data for two or three black holes

PERFORMANCE EVALUATION OF FORMULATED AND COMMERCIALLY AVAILABLE DE-EMULSIFIERS

The de-emulsification of water-in-oil emulsion of Ogharefe crude oil samples was studied by using formulated polyester based de-emulsifier sample A and a commercially available de-emulsifier sample C. The bottle test method was used to screen the de-emulsifier samples. The performance of the de-emulsifiers was expressed in terms of percentage of water separated from 100 ml samples of emulsions. For both the formulated and commercial de-emulsifiers, the performance increased with increased concentration of the de-emulsifiers, separation time and operating temperature. The effect of the operating temperature was much higher and there was a linear between performance and temperature. The performance of the best of the formulated de-emulsifiers, sample A, was better than that of the commercial de-emulsifier under all the conditions of this study- the volume of water expelled by sample A was 5 times that of the commercial one at 30oC. At 70oC, this ratio increased to 14

Applications of the calculus of variations to aircraft performance

Variational calculus used to describe optimum aircraft flight trajectorie

The social geography of childcare: 'making up' the middle class child

Childcare is a condensate of disparate social forces and social processes. It is gendered and classed. It is subject to an excess of policy and political discourse. It is increasingly a focus for commercial exploitation. This is a paper reporting on work in progress in an ESRC funded research project (R000239232) on the choice and provision of pre-school childcare by middle class (service class) families in two contrasting London locations. Drawing on recent work in class analysis the paper examines the relationships between childcare choice, middle class fractions and locality. It suggests that on the evidence of the findings to date, there is some evidence of systematic differences between fractions in terms of values, perspectives and preferences for childcare, but a more powerful case for intra-class similarities, particularly when it comes to putting preferences into practice in the 'making up of a middle class child' through care and education