Representation Of Moments Research Articles

Black swan, white masks: Contesting cosmopolitanism and double misrecognition in a gay tourist town

This article discusses the effects that constructions of lesbianism – generated and circulated widely throughout Anglo-American media – had on normative discourses of gender and sexuality amongst British migrants, living in the affluent coastal tourist town of Sitges, in Spain. Marketed as a cosmopolitan location par excellence, Sitges’ identity is built largely on its reputation for playing host to an internationally diverse gay community, subsequently understood to evince an atmosphere of openness and tolerance. And yet drawing on the work of Frantz Fanon (1952/1967) and Kelly Oliver (2001), I suggest that the visibility of feminine lesbianism in this context was resignified through those media images, constituting a ‘double misrecognition’, which saw all female homosexuality paradoxically become invisible at the exact moment representation was explicitly deemed to have been achieved. Far from elaborating a cosmopolitan ‘openness towards difference’, I argue that the resulting double misrecognition actually substantiated highly conservative gender norms, even as it masqueraded as the opposite.

Many-Dimensional Generalized Moment Representations and Padé -Type Approximants for Functions of Many Variables

We propose an approach to the construction of multidimensional Pad´e-type approximants for analytic functions based on the extension of Dzyadyk’s method of generalized moment representations.

On push-forward representations in the standard gyrokinetic model

Two representations of fluid moments in terms of a gyro-center distribution function and gyro-center coordinates, which are called push-forward representations, are compared in the standard electrostatic gyrokinetic model. In the representation conventionally used to derive the gyrokinetic Poisson equation, the pull-back transformation of the gyro-center distribution function contains effects of the gyro-center transformation and therefore electrostatic potential fluctuations, which is described by the Poisson brackets between the distribution function and scalar functions generating the gyro-center transformation. Usually, only the lowest order solution of the generating function at first order is considered to explicitly derive the gyrokinetic Poisson equation. This is true in explicitly deriving representations of scalar fluid moments with polarization terms. One also recovers the particle diamagnetic flux at this order because it is associated with the guiding-center transformation. However, higher-order solutions are needed to derive finite Larmor radius terms of particle flux including the polarization drift flux from the conventional representation. On the other hand, the lowest order solution is sufficient for the other representation, in which the gyro-center transformation part is combined with the guiding-center one and the pull-back transformation of the distribution function does not appear.

Effective elastic moduli of a particulate composite in terms of the dipole moments and property contribution tensors

The paper focuses on the comparison of two approaches used for calculation of the effective elastic properties of particulate composites: the dipole moments representation and the technique based on property contribution tensors. Its specific goal is to bridge the gap between the two methods and to identify the key microstructural parameters affecting overall elastic stiffness of heterogeneous materials. The basic concepts of the homogenization theory including a consistent way of introducing the macroscopic field parameters are discussed and clarified. We provide a detailed comparison of the analytical expressions for the dipole moment tensors obtained by the multipole expansion method and for the stiffness contribution tensors and show that they coincide.

High-energy damping by particle-hole excitations in the spin-wave spectrum of iron-based superconductors

Using a degenerate double-exchange model, we investigate the spin excitation spectra of iron pnictides. The model consists of local spin moments on each Fe site, as well as itinerant electrons from the degenerate $d_{xz}$ and $d_{yz}$ orbitals. The local moments interact with each other through antiferromagnetic $J_{1}$-$J_{2}$ Heisenberg interactions, and they couple to the itinerant electrons through a ferromagnetic Hund coupling. We employ the fermionic spinon representation for the local moments and perform a generalized random-phase approximation calculation on both spinons and itinerant electrons. We find that in the $\left(\pi,0\right)$ magnetically-ordered state, the spin-wave excitation at $\left(\pi,\pi\right)$ is pushed to a higher energy due to the presence of itinerant electrons, which is consistent with a previous study using the Holstein-Primakoff transformation. In the paramagnetic state, the particle-hole continuum keeps the collective spin excitation near $\left(\pi,\pi\right)$ at a higher energy even without any $C_{4}$ symmetry breaking. The implications for recent high temperature neutron scattering measurements will be discussed.

A new method for evaluating Borgonovo moment-independent importance measure with its application in an aircraft structure

The moment-independent importance measure proposed by Borgonovo, which is defined as the average shift between the unconditional and conditional probability density functions (PDFs) of model output, is widely used to evaluate the influence of input uncertainty on the entire output distribution. And how to exactly and efficiently estimate the PDFs remains a crucial and challenging problem. In this paper, a novel PDF estimation based method is proposed to efficiently evaluate the moment-independent index. Firstly, the PDF of the model output is obtained based on the concepts of maximum entropy, fractional moment and high dimensional model representation. Secondly, the Nataf transformation is utilized to estimate the joint PDF of the output and input variable. Finally, the index can be easily computed using the generated correlated standard normal samples. Thus the importance measure can be calculated with high efficiency and accuracy using this proposed composited method. Several examples are employed to demonstrate the advantages of the proposed method. Meanwhile, the importance analysis of a stiffening rib of the wing leading edge in a certain aircraft also verifies its good engineering applicability.

Тривимірні узагальнені моментні зображення та апроксимації типу Паде для функцій трьох змінних

Тривимірні узагальнені моментні зображення та апроксимації типу Паде для функцій трьох змінних

Probabilistic approach to Appell polynomials

In this paper we study Appell polynomials by connecting them to random variables. This probabilistic approach yields, e.g., the mean value property which is fundamental in the sense that many other properties can be derived from it. We also discuss moment representations of Appell polynomials. In the latter part of the paper the presented general theory is applied to study some classical explicitly given polynomials.

Risk-Adjusted Option-Implied Moments

Option-implied moments, like implied volatility, contain useful information about an underlying asset's return distribution but are derived under the risk-neutral probability measure. This paper provides a direct way of converting risk-neutral moments into the corresponding physical moments, which are required for many applications. The main result is a representation of physical moments in terms of observed option prices and a representative investor's preferences. As an empirical application of this result, we provide implied estimates of the representative stock market investor's disappointment aversion using S&P 500 index option prices. We find that disappointment aversion has a procyclical pattern. It is high in times of high index levels and declines when the index falls. We confirm the view that investors with high risk aversion and disappointment aversion leave the stock market during times of turbulence and reenter it after a period of high returns.

Female trauma in the films of Szabolcs Hajdu, David Lynch, Cristian Mungiu and Peter Strickland

A number of twenty-first century art films, set in an ‘Eastern European’ linguistic, cultural or mythical background have traumatized female leads: Tamara (Szabolcs Hajdu, 2004), Inland Empire (David Lynch, 2006), 4 luni, 3 săptămâni şi 2 zile/4 months, 3 weeks, and 2 days (Cristian Mungiu, 2007), Katalin Varga (Peter Strickland, 2009) and Bibliothèque Pascal (Szabolcs Hajdu, 2010). Since the audio-visual representation of moments of trauma is quite consistent in these films, despite their belonging to different production models and artistic canons (New Hungarian Cinema, American postmodern indie, Romanian New Wave, British transnational cinema), the article presents a detailed analysis of their ‘traumatic moments’, using Michel Chion's model of sound in film, and trauma theory. The author argues that the traumatized female leads can be interpreted as allegorical representations of ‘Eastern Europe’ and its collectivities, also haunted by traumatic recurring experiences. This interpretation is inspired by Ismail Xavier's allegorical reading of female characters in Latin American cinema and by Mark Betz’ concept of ‘wandering women’ in European art cinema. The author also reinterprets Fredric Jameson's well known idea of the ‘national allegory in third-world literature’ to apply it to transnational cinematic material.

Accurate Coulomb Potentials for Periodic and Molecular Systems through Density Fitting

We present a systematically improvable density fitting scheme designed for accurate Coulomb potential evaluation of periodic and molecular systems. The method does not depend on the way the density is calculated, allowing for a basis set expansion as well as a numerical representations of the orbitals. The scheme is characterized by a partitioning of the density into local contributions that are expanded by means of cubic splines. For three-dimensional periodic systems, the long-range contribution to the Coulomb potential is treated with the usual reciprocal space representation of the multipole moments, while in one- and two-dimensional systems, it is calculated via a new algorithm based on topological extrapolation. The efficiency and numerical robustness of the scheme is assessed for a number of periodic and nonperiodic systems within the framework of density-functional theory.

Letter to the Editor: Joint Moments in the Joint Coordinate System, Euler or Dual Euler Basis

Letter to the Editor: Joint Moments in the Joint Coordinate System, Euler or Dual Euler Basis

Two-Dimensional Generalized Moment Representations and Padé Approximations for Some Humbert Series

By extending Dzyadyk’s method of generalized moment representations to the case of two-dimensional number sequences, we construct and study Pade approximants for some confluent Humbert hypergeometric series.

Time varying moments, regime switch, and crisis warning: The birth–death process with changing transition probability

The sub-prime crisis in the U.S. reveals the limitation of diversification strategy based on mean–variance analysis. A regime switch and a turning point can be observed using a high moment representation and time-dependent transition probability. Up–down price movements are induced by interactions among agents, which can be described by the birth–death (BD) process. Financial instability is visible by dramatically increasing 3rd to 5th moments one-quarter before and during the crisis. The sudden rising high moments provide effective warning signals of a regime-switch or a coming crisis. The critical condition of a market breakdown can be identified from nonlinear stochastic dynamics. The master equation approach of population dynamics provides a unified theory of a calm and turbulent market.

Chronicles from Majnun until Layla

Abstract Chronicles from Majnun until Layla is a film project structured in three stages: 1.) The Museum of Modern Iranian History (2011–2013), 2.) Layla and Majnun (in preparation), and 3.) The Film (in preparation). Each stage bears its own approach, format, and mode of presentation. The first two stages are conceived as preparation for the third and final stage: the merging moment, which will be in the form of a feature-length, hybrid fiction/documentary film. The film depicts a couple, lovers, visiting a virtual museum of modern Iranian history. The lovers appear both as themselves and as “Layla and Majnun,” characters adapted from a classical Middle Eastern love tale. As they walk the museum, the couple engages in dialogue about their individual and collective stories, memories, dreams, rages, and desires. The lovers' affairs and conversations interact with the representations of the major historical moments of Iran being documented in the museum. In Stage 1, through the museum's architectural design and references to an official Iranian narrative taken from a high-school textbook, the various historical periods of Iran get transformed into Kairos (the Now), contradicting Chronos and scientific and analytical historiography.

Two-Dimensional Generalized Moment Representations and Rational Approximations of Functions of Two Variables

The Dzyadyk method of generalized moment representations is extended to the case of two-dimensional sequences and used to construct Pade approximants for functions of two variables.

Why the Show Must Not Go On: “Real Character” and the Absence of Theatrical Performances in Mansfield Park

This article revisits the question of why Jane Austen refuses to portray any theatrical performances within Mansfield Park (1814), even though much of the plot concerns a group of young people attempting to put on a play. While scholars have generally abandoned the idea that this choice reveals Austen’s puritanical distaste for the theatre, it remains unusual in the context of other roughly contemporary novels that also involve the theatre or theatricals. Looking at examples of such theatrical novels shows that their staging of performances tends to disrupt the idea of character as stable identity, in much the same way that Lisa Freeman has suggested theatre itself did at the time. Though her use of interiority has been much discussed as the tool Austen employs to construct a sense of essential identity for her characters, her decision to forego the direct representation of various theatrical moments while focusing readers’ attention on their consequences is another way Austen convinces us that the novel is able to distinguish “real” character from the performance of it.

Estimating ensemble average power delivered by a piezoelectric patch actuator to a non-deterministic subsystem

Abstract Engineering systems such as aircraft, ships and automotive are considered built-up structures. Dynamically they are taught of as being fabricated from many components that are classified as ‘deterministic subsystems’ (DS) and ‘non-deterministic subsystems’ (Non-DS). Structures' response of the DS is deterministic in nature and analysed using deterministic modelling methods such as finite element (FE) method. The response of Non-DS is statistical in nature and estimated using statistical modelling technique such as statistical energy analysis (SEA). SEA method uses power balance equation, in which any external input to the subsystem must be represented in terms of power. Often, input force is taken as point force and ensemble average power delivered by point force is already well-established. However, the external input can also be applied in the form of moments exerted by a piezoelectric (PZT) patch actuator. In order to be able to apply SEA method for input moments, a mathematical representation for moment generated by PZT patch in the form of average power is needed, which is attempted in this paper. A simply-supported plate with attached PZT patch is taken as a benchmark model. Analytical solution to estimate average power is derived using mobility approach. Ensemble average of power given by the PZT patch actuator to the benchmark model when subjected to structural uncertainties is also simulated using Lagrangian method and FEA software. The analytical estimation is compared with the Lagrangian model and FE method for validation. The effects of size and location of the PZT actuators on the power delivered to the plate are later investigated.

Optimal and suboptimal quadratic forms for noncentered Gaussian processes

Individual random trajectories of stochastic processes are often analyzed by using quadratic forms such as time averaged (TA) mean square displacement (MSD) or velocity auto-correlation function (VACF). The appropriate quadratic form is expected to have a narrow probability distribution in order to reduce statistical uncertainty of a single measurement. We consider the problem of finding the optimal quadratic form that minimizes a chosen cumulant moment (e.g., the variance) of the probability distribution, under the constraint of fixed mean value. For discrete noncentered Gaussian processes, we construct the optimal quadratic form by using the spectral representation of cumulant moments. Moreover, we obtain a simple explicit formula for the smallest achievable cumulant moment that may serve as a quality benchmark for other quadratic forms. We illustrate the optimality issues by comparing the optimal variance with the variances of the TA MSD and TA VACF of fractional Brownian motion superimposed with a constant drift and independent Gaussian noise.

On Representations for Joint Moments Using a Joint Coordinate System

In studies of the biomechanics of joints, the representation of moments using the joint coordinate system has been discussed by several authors. The primary purpose of this technical brief is to emphasize that there are two distinct, albeit related, representations for moment vectors using the joint coordinate system. These distinct representations are illuminated by exploring connections between the Euler and dual Euler bases, the "nonorthogonal projections" presented in a recent paper by Desroches et al. (2010, "Expression of Joint Moment in the Joint Coordinate System," ASME J. Biomech. Eng., 132(11), p. 11450) and seminal works by Grood and Suntay (Grood and Suntay, 1983, "A Joint Coordinate System for the Clinical Description of Three-Dimensional Motions: Application to the Knee," ASME J. Biomech. Eng., 105(2), pp. 136-144) and Fujie et al. (1996, "Forces and Moment in Six-DOF at the Human Knee Joint: Mathematical Description for Control," Journal of Biomechanics, 29(12), pp. 1577-1585) on the knee joint. It is also shown how the representation using the dual Euler basis leads to straightforward definition of joint stiffnesses.