A Study of Techniques for Calculating Motion Drive Signals for Flight Simulators

Development and evaluation of experimental test plan for solutions of motion drive problem in formation flying task with flight simulator

OPTIMAL GRADE DEFINITIONS FOR MULTIPLE QUALITY CHARACTERISTICS

The growing importance of quality in agricultural markets makes effective segregation and grading essential to efficient marketing strategy. In this paper, we develop an economic model, potentially applicable to many products, to determine optimal segregation strategies based on multiple stochastic quality measures. The model is applied to Oklahoma wheat quality data.Marketing,

How Does Law Affect Finance? An Empirical Examination of Tunneling in an Emerging Market

This paper documents that law affects finance in emerging markets through the methods used by controlling shareholders to “tunnel” wealth out of the firm. We find that Bulgarian securities law enabled financial tunneling via dilution and freeze-out tender offers. During the period 1999- 2001, about two-thirds of the 1,040 firms on the Bulgarian Stock Exchange were delisted. Freeze-out tender offers for minority shares averaged about 25% of the shares’ intrinsic value. Bulgarian securities law changes in 2002 made financial tunneling more costly for controlling shareholders. Subsequent increases in stock market valuations and liquidity suggest that controlling shareholders have shifted from financial tunneling to less value-destroying methods, such as transfer pricing, to extract wealth from firms.Tunneling, freeze-out, controlling shareholders, appraisal rights, preemptive rights

Accelerating Asymptotically Exact MCMC for Computationally Intensive Models via Local Approximations

We construct a new framework for accelerating Markov chain Monte Carlo in posterior sampling problems where standard methods are limited by the computational cost of the likelihood, or of numerical models embedded therein. Our approach introduces local approximations of these models into the Metropolis-Hastings kernel, borrowing ideas from deterministic approximation theory, optimization, and experimental design. Previous efforts at integrating approximate models into inference typically sacrifice either the sampler's exactness or efficiency; our work seeks to address these limitations by exploiting useful convergence characteristics of local approximations. We prove the ergodicity of our approximate Markov chain, showing that it samples asymptotically from the \emph{exact} posterior distribution of interest. We describe variations of the algorithm that employ either local polynomial approximations or local Gaussian process regressors. Our theoretical results reinforce the key observation underlying this paper: when the likelihood has some \emph{local} regularity, the number of model evaluations per MCMC step can be greatly reduced without biasing the Monte Carlo average. Numerical experiments demonstrate multiple order-of-magnitude reductions in the number of forward model evaluations used in representative ODE and PDE inference problems, with both synthetic and real data.Comment: A major update of the theory and example

Can a 3+2 Oscillation Model Explain the NuTeV Electroweak Results?

The weak mixing angle result from NuTeV falls three standard deviations above the value determined by global electroweak fits. It has been suggested that one possible explanation for this result could be the oscillation of electron neutrinos in the NuTeV beam to sterile neutrinos. This article examines several cases of masses and mixings for 3+2 neutrino oscillation models which fit the current oscillation data at 99% CL. We conclude that electron to sterile neutrino oscillations can account for only up to a third of a standard deviation between the NuTeV determination of the weak mixing angle and the standard model.Comment: 3 pages, 2 figures, submitted to Brief Report

Limits of stakeholder participation in sustainable development : "where facts are few, experts are many"

Extract from: The Mediterranean coastal areas from watershed to the sea : interactions and changes / by L.F. Cassar ... [et al.]. Proceedings of the MEDCORE International conference, Florence, 10th-14th November 2005The notion of including stakeholders, those affected (positively or negatively) by a sustainable development programme in both its design and implementation, has become a central concern for those implementing such programmes. Such an approach is often referred to as ‘stakeholder participation’, as ‘participatory development’ or more simply still as ‘participation’. How best to achieve this has been the topic of a substantial literature, with a host of different methodologies presented and promoted. Each has its own advantages and disadvantages, but there has been surprisingly little discussion in the sustainable development literature as to the limits and dangers of participation irrespective of the approach employed to ‘best’ facilitate it. Inter-linked with the limits of participation is the role of specialists and expert opinion in sustainable development. This paper discusses the results of participatory exercises conducted in Gozo (Malta) between 2003 and 2005. On the positive side, participation yielded many useful and interesting insights and invoked a sense of ‘involvement’ in sustainable development, but there were problems and these are discussed in this paper. For example, the outcome of the exercise crucially depends upon representation, and a simplified vision of ‘community’ often employed in participation to make it practicable can load the process in favour of certain stakeholder groups at the expense of others.peer-reviewe

The sensitivity of Cherenkov telescopes to dark matter and astrophysical anisotropies in the diffuse gamma-ray background

In this article, the capability of present (H.E.S.S., MAGIC, VERITAS) and planned (CTA) ground-based Cherenkov telescope systems for detecting angular anisotropies in the diffuse gamma-ray background is investigated. Following up on a study of the impact of instrumental characteristics (effective area, field of view, angular resolution, and background rejection efficiency), the first part examines the influence of different observational strategies, i.e. whether a single deep observation or a splitting over multiple shallow fields is preferred. In the second part, the sensitivity to anisotropies generated by self-annihilating dark matter is studied for different common dark matter models. We find that a relative contribution of ~10% from dark matter annihilation to the extra-galactic diffuse gamma-ray background can be detected with planned configurations of CTA. In terms of the thermally-averaged self-annihilation cross section, the sensitivity of CTA corresponds to values below the thermal freeze-out expectation = 3 x 10-26 cm3s-1 for dark matter particles lighter than ~200 GeV. We stress the importance of constraining anisotropies from unresolved astrophysical sources with currently operating instruments already, as a novel and complementary method for investigating the properties of TeV sources.Comment: 27 pages, 6 figures, 2 tables; v2: new paragraphs and figures added. Improvements in clarity of the text and readability of the figures. Conclusions unchanged. Matches published version on JCA

To Tube or Not to Tube? The Role of Intubation during Stroke Thrombectomy.

In the 10 years since the FDA first cleared the use of endovascular devices for the treatment of acute stroke, definitive evidence that such therapy improves outcomes remains lacking. The decision to intubate patients undergoing stroke thrombectomy impacts multiple variables that may influence outcomes after stroke. Three main areas where intubation may deleteriously affect acute stroke management include the introduction of delays in revascularization, fluctuations in peri-procedural blood pressure, and hypocapnia, resulting in cerebral vasoconstriction. In this mini-review, we discuss the evidence supporting these limitations of intubation during stroke thrombectomy and encourage neurohospitalists, neurocritical care specialists, and neurointerventionalists to carefully consider the decision to intubate during thrombectomy and provide strategies to avoid potential complications associated with its use in acute stroke