A general approach to Bayesian portfolio optimization

We develop a general approach to portfolio optimization taking account of estimation risk and stylized facts of empirical finance. This is done within a Bayesian framework. The approximation of the posterior distribution of the unknown model parameters is based on a parallel tempering algorithm. The portfolio optimization is done using the first two moments of the predictive discrete asset return distribution. For illustration purposes we apply our method to empirical stock market data where daily asset logreturns are assumed to follow an orthogonal MGARCH process with t-distributed perturbations. Our results are compared with other portfolios suggested by popular optimization strategies. --Bayesian portfolio optimization,Gordin's condition,Markov chain Monte Carlo,Stylized facts

Reconstruction of Residual Stress in a Welded Plate Using the Variational Eigenstrain Approach

We present the formulation for finding the distribution of eigenstrains, i.e. the sources of residual stress, from a set of measurements of residual elastic strain (e.g. by diffraction), or residual stress, or stress redistribution, or distortion. The variational formulation employed seeks to achieve the best agreement between the model prediction and some measured parameters in the sense of a minimum of a functional given by a sum over the entire set of measurements. The advantage of this approach lies in its flexibility: different sets of measurements and information about different components of the stress-strain state can be incorporated. We demonstrate the power of the technique by analysing experimental data for welds in thin sheet of a nickel superalloy aerospace material. Very good agreement can be achieved between the prediction and the measurement results without the necessity of using iterative solution. In practice complete characterisation of residual stress states is often very difficult, due to limitations of facility access, measurement time or specimen dimensions. Implications of the new technique for experimental analysis are all the more significant, since it allows the reconstruction of the entire stress state from incomplete sets of data.Comment: 16 pages, 17 figure

Systematic study of infrared energy corrections in truncated oscillator spaces

We study the convergence properties of nuclear binding energies and two-neutron separation energies obtained with self-consistent mean-field calculations based on the Hartree-Fock-Bogolyubov (HFB) method with Gogny-type effective interactions. Owing to lack of convergence in a truncated working basis, we employ and benchmark one of the recently proposed infrared energy correction techniques to extrapolate our results to the limit of an infinite model space. We also discuss its applicability to global calculations of nuclear masses.Comment: 12 pages, 12 figure

Restriction of odd degree characters and natural correspondences

Let $q$ be an odd prime power, $n > 1$, and let $P$ denote a maximal parabolic subgroup of $GL_n(q)$ with Levi subgroup $GL_{n-1}(q) \times GL_1(q)$. We restrict the odd-degree irreducible characters of $GL_n(q)$ to $P$ to discover a natural correspondence of characters, both for $GL_n(q)$ and $SL_n(q)$. A similar result is established for certain finite groups with self-normalizing Sylow $p$-subgroups. We also construct a canonical bijection between the odd-degree irreducible characters of $S_n$ and those of $M$, where $M$ is any maximal subgroup of $S_n$ of odd index; as well as between the odd-degree irreducible characters of $G = GL_n(q)$ or $GU_n(q)$ with $q$ odd and those of $N_{G}(P)$, where $P$ is a Sylow $2$-subgroup of $G$. Since our bijections commute with the action of the absolute Galois group over the rationals, we conclude that the fields of values of character correspondents are the same. We use this to answer some questions of R. Gow

Black Bottom

For this paper, I chose to examine the character of Beneatha Younger from A Raisin in the Sun, her relationships with other characters, and how it relates to Afrocentrism

Body randomization reduces the sim-to-real gap for compliant quadruped locomotion

Designing controllers for compliant, underactuated robots is challenging and usually requires a learning procedure. Learning robotic control in simulated environments can speed up the process whilst lowering risk of physical damage. Since perfect simulations are unfeasible, several techniques are used to improve transfer to the real world. Here, we investigate the impact of randomizing body parameters during learning of CPG controllers in simulation. The controllers are evaluated on our physical quadruped robot. We find that body randomization in simulation increases chances of finding gaits that function well on the real robot

Cognitive-linguistic manipulation and persuasion in Agatha Christie

This thesis presents some of the many methods which Agatha Christie uses to manipulate readers away from and towards the eventual resolutions of her fiction. It draws on a variety of linguistic, psychological, narratological and stylistic models to describe the specific techniques employed by Christie to manipulate and distract her readers. The research undertaken employs practical studies in schemata, scenario-dependence, depth of cognitive processing, rhetorical-structural persuasion, unreliable narration, social cognition theories of character attribution, and ideas from the study of mind style to analyse manipulation in some of Christie’s most notable works. These works include the novels Murder on the Orient Express, The Murder of Roger Ackroyd, Death in the Clouds, Cards on the Table and The ABC Murders, in addition to lesser-known short stories from The Thirteen Problems and Poirot Investigates. More specifically, following the introduction, the analyses in Chapter 2 operate through models of the psychological processing of texts and the way that linguistic indicators are interpreted by readers. ‘Red herrings’ and ‘buried clues’ are defined and examined using cognitive theories of schemata (information networks), scenario-dependence and a reader’s depth of processing. This is followed by Chapter 3, a rhetorical and structural analysis of persuasive practices within an extract of Christie’s fiction, where her detective Hercule Poirot attempts to convince both the assembled characters and the novel’s reader of the necessary truth of the solution he is presenting. In this chapter I introduce my own adaptation of Rhetorical Structure Theory designed for analyses of long extracts of a narrative text is also introduced. Chapter 4 looks at narratological and cognitive methods of describing character and narrator unreliability and ambiguity, through studies of an unreliable narrator, the nature of some witnesses’ minds within different novels, and the presentation of the ambiguous thoughts of an important suspect using techniques taken from the study of mind style. The thesis aims primarily to describe and illustrate in a systematic manner a selection of the many different ways in which Christie manipulates readers, and points the way to other techniques of this sort. The breadth of the frameworks employed is intended to emphasise the range of Christie’s techniques, and to demonstrate that detective fiction contains many uses of complex manipulation which would bear further study

Elkouri: HOW ARBITRATION WORKS.

A Review of HOW ARBITRATION WORKS. By Frank Elkouri