Multidimensional sampling for simulation and integration: measures, discrepancies, and quasi-random numbers

This is basically a review of the field of Quasi-Monte Carlo intended for computational physicists and other potential users of quasi-random numbers. As such, much of the material is not new, but is presented here in a style hopefully more accessible to physicists than the specialized mathematical literature. There are also some new results: On the practical side we give important empirical properties of large quasi-random point sets, especially the exact quadratic discrepancies; on the theoretical side, there is the exact distribution of quadratic discrepancy for random point sets.Comment: 51 pages. Full paper, including all figures also available at: ftp://ftp.nikhef.nl/pub/preprints/96-017.ps.gz Accepted for publication in Comp.Phys.Comm. Fixed some typos, corrected formula 108,figure 11 and table

On the computation of the maximal structured singular value for aeronautical applications

peer-reviewed                                                                                                                             This paper considers the necessary transformations and the computational issues associated with the determination of the maximal structured singular value without the use of a frequency gridding strategy. It is shown that, for the case of purely real model perturbations, convergence difficulties exist in determining bounds on the maximal structured singular value using existing Matlab software. A new computational scheme is presented which improves on existing methods for the computation of the worst case combination of real uncertain parameters. This scheme easily outperforms regularisation type solutions, which have been suggested as one way of improving the convergence properties of a strictly real robustness analysis. The improvement is illustrated on a well known civil aircraft robustness analysis example.    ACCEPTEDpeer-reviewe

Studies in the cycloproparene series: cycloaddition reactions of diarylmethylidenecycloproparenes

Journal ArticleDiarylmethylidenecyclopropanaphthalenes 4b-d add diphenylisobenzofuran (DPIBF) and α-pyrone across the exocyclic double bond to give ring expanded products 11b-d and 13b-d that result from subsequent relief of ring strain in the non-isolable spirocyclic intermediates 10 and 12, respectively. The benzene homologues 3b and 3c add DPIBF across the bridge bond to give the norcaradiene adducts 19b and 19c

When The Moon Begins To Shine : Through The Pines Of Carolin\u27

https://digitalcommons.library.umaine.edu/mmb-vp/2724/thumbnail.jp

The Impact of Emigration on Real Wages in Ireland, 1850-1914

[Excerpt] The chapter is organized as follows. First, we examine the growth of Irish wages and living standards in comparison with other countries. Second, we examine the hypothesis that the Irish agricultural wage was responsive to movements in the male population. Third, we attempt to estimate the effect of emigration on the population and labor force of Ireland from 1851-1911. In order to estimate the impact of faster labor force growth, we specify a computable general equilibrium model of the Irish economy. Then the effects of emigration are evaluated in a general equilibrium framework. Finally, we summarize the main findings of the chapter in a short conclusion

Optimal strategies for a game on amenable semigroups

The semigroup game is a two-person zero-sum game defined on a semigroup S as follows: Players 1 and 2 choose elements x and y in S, respectively, and player 1 receives a payoff f(xy) defined by a function f from S to [-1,1]. If the semigroup is amenable in the sense of Day and von Neumann, one can extend the set of classical strategies, namely countably additive probability measures on S, to include some finitely additive measures in a natural way. This extended game has a value and the players have optimal strategies. This theorem extends previous results for the multiplication game on a compact group or on the positive integers with a specific payoff. We also prove that the procedure of extending the set of allowed strategies preserves classical solutions: if a semigroup game has a classical solution, this solution solves also the extended game.Comment: 17 pages. To appear in International Journal of Game Theor

On a Tree and a Path with no Geometric Simultaneous Embedding

Two graphs $G_1=(V,E_1)$ and $G_2=(V,E_2)$ admit a geometric simultaneous embedding if there exists a set of points P and a bijection M: P -> V that induce planar straight-line embeddings both for $G_1$ and for $G_2$. While it is known that two caterpillars always admit a geometric simultaneous embedding and that two trees not always admit one, the question about a tree and a path is still open and is often regarded as the most prominent open problem in this area. We answer this question in the negative by providing a counterexample. Additionally, since the counterexample uses disjoint edge sets for the two graphs, we also negatively answer another open question, that is, whether it is possible to simultaneously embed two edge-disjoint trees. As a final result, we study the same problem when some constraints on the tree are imposed. Namely, we show that a tree of depth 2 and a path always admit a geometric simultaneous embedding. In fact, such a strong constraint is not so far from closing the gap with the instances not admitting any solution, as the tree used in our counterexample has depth 4.Comment: 42 pages, 33 figure

Against the Tide. A Critical Review by Scientists of How Physics and Astronomy Get Done

Nobody should have a monopoly of the truth in this universe. The censorship and suppression of challenging ideas against the tide of mainstream research, the blacklisting of scientists, for instance, is neither the best way to do and filter science, nor to promote progress in the human knowledge. The removal of good and novel ideas from the scientific stage is very detrimental to the pursuit of the truth. There are instances in which a mere unqualified belief can occasionally be converted into a generally accepted scientific theory through the screening action of refereed literature and meetings planned by the scientific organizing committees and through the distribution of funds controlled by "club opinions". It leads to unitary paradigms and unitary thinking not necessarily associated to the unique truth. This is the topic of this book: to critically analyze the problems of the official (and sometimes illicit) mechanisms under which current science (physics and astronomy in particular) is being administered and filtered today, along with the onerous consequences these mechanisms have on all of us.\ud \ud The authors, all of them professional researchers, reveal a pessimistic view of the miseries of the actual system, while a glimmer of hope remains in the "leitmotiv" claim towards the freedom in doing research and attaining an acceptable level of ethics in science