Comparativism and the Measurement of Partial Belief

According to comparativism, degrees of belief are reducible to a system of purely ordinal comparisons of relative confidence. (For example, being more confident that P than that Q, or being equally confident that P and that Q.) In this paper, I raise several general challenges for comparativism, relating to (i) its capacity to illuminate apparently meaningful claims regarding intervals and ratios of strengths of belief, (ii) its capacity to draw enough intuitively meaningful and theoretically relevant distinctions between doxastic states, and (iii) its capacity to handle common instances of irrationality

Machine Learning and Galaxy Formation

Galaxy formation and evolution involves the interplay of a large number of complex, non-linear processes, many of which act at scales beneath those accessible to even the most modern galaxy formation simulations. Galaxy formation models therefore include parameterised sub-grid processes, which must be calibrated against selected observational constraints. In this thesis, I explore the application of machine learning and optimisation methods to characterize and calibrate a semi-analytic model of galaxy formation, GALFORM. I investigate the application of deep learning to this problem, building an accurate emulator of the full model over a ten dimensional parameter space from just 1000 GALFORM evaluations. I investigate the calibration of GALFORM to a large number of datasets, and investigate tensions between different choices of calibration datasets and the parameters themselves. Next, I present an investigation into the controversial requirement for a top-heavy stellar initial mass function in starbursts in the GALFORM model, which it was argued was necessary for the model to match the constraints from the number counts of sub-millimeter galaxies, their redshift distribution, and the local K-band luminosity function. Here, I apply Bayesian Optimisation to search the model parameter space for optimal fits to these datasets, and demonstrate that GALFORM is not capable of reproducing these data simultaneously with a solar neighbourhood IMF, and that the top-heavy IMF alleviates this problem

The spermatogenesis of Sceloporus undulatus

Text taken from page 8 of the Introduction section of this thesis: The present research was undertaken in the spring of 1913 at the suggestion of Dr. George Lefevre and is an attempt at tracing the behavior of the chromosomes in the common fence swift, Sceloporus undulatus

‘Global Britain’? assessing Boris Johnson’s major changes to national security and foreign policy

There is a real risk that the shake-up of UK national security and foreign policy currently being orchestrated by Number 10 will not provide the solutions the country needs, write Edward Elliott and Sam Goodman. Here they interview former National Security Advisers, former Foreign Secretaries, former foreign policy advisers to PMs, and former senior diplomats, to assess recent developments and their potential repercussions

GelSlim: A High-Resolution, Compact, Robust, and Calibrated Tactile-sensing Finger

This work describes the development of a high-resolution tactile-sensing finger for robot grasping. This finger, inspired by previous GelSight sensing techniques, features an integration that is slimmer, more robust, and with more homogeneous output than previous vision-based tactile sensors. To achieve a compact integration, we redesign the optical path from illumination source to camera by combining light guides and an arrangement of mirror reflections. We parameterize the optical path with geometric design variables and describe the tradeoffs between the finger thickness, the depth of field of the camera, and the size of the tactile sensing area. The sensor sustains the wear from continuous use -- and abuse -- in grasping tasks by combining tougher materials for the compliant soft gel, a textured fabric skin, a structurally rigid body, and a calibration process that maintains homogeneous illumination and contrast of the tactile images during use. Finally, we evaluate the sensor's durability along four metrics that track the signal quality during more than 3000 grasping experiments.Comment: RA-L Pre-print. 8 page

Unawareness and Implicit Belief

Possible worlds models of belief have difficulties accounting for unawareness, the inability to entertain (and hence believe) certain propositions. Accommodating unawareness is important for adequately modelling epistemic states, and representing the informational content to which agents have in principle access given their explicit beliefs. In this paper, I develop a model of explicit belief, awareness, and informational content, along with an sound and complete axiomatisation. I furthermore defend the model against the seminal impossibility result of Dekel, Lipman and Rustichini, according to which three intuitive conditions preclude non-trivial unawareness on any possible worlds model of belief