Der kontrollierte Stoß Mathelitsch, Leopold; Thaller, Sigrid
Physik in unserer Zeit,
July 2020, Letnik:
51, Številka:
4
Journal Article
Zusammenfassung
Das Billardspiel ist über ein halbes Jahrtausend alt. Seine Physik fasziniert die Forschung seit Huygens bis heute. Die aus der Perspektive der Physik entscheidenden Elemente sind der ...Stoß mit dem Queue, der Kontakt zwischen den Bällen und der Kontakt zwischen Ball und Bande. Gestoßen werden kann die Kugel zentral, ober‐ oder unterhalb ihres Mittelpunkts sowie seitlich versetzt. Davon hängt ihr Verhalten ab, ob sie rollt, gleitet, etwa einen Topspin oder einen sonstigen Effet mitbekommt. Während der Kontakt zwischen zwei Bällen wegen der geringen Reibung wie ein elastischer Stoß behandelbar ist, spielt der Effet beim Kontakt mit der Bande eine wichtige Rolle. Beim Sinai‐Billard besitzt der Tisch runde Ecken oder ein rundes Hindernis, die Folge ist chaotisches Verhalten. Das wurde mit ultrakalten Atomen in entsprechend geformten Lichtpotentialen demonstriert.
Das trickreiche Stoßen der Billardkugeln über Banden fasziniert Physiker seit Jahrhunderten. Heute dürfen es gerne auch ultrakalte Atome sein.
We are very sad to say that Professor Roland Billard, emeritus professor at the French Museum of Natural History passed away on 26 March 2019, however, his presence will remain in our memory. Prof. ...Billard was a brilliant scientist and an outstandingly generous man, all who knew him will appreciate these attributes.
•We are very sad to say that Professor Roland Billard, emeritus professor at the French Museum of Natural History passed away on 26 March 2019.•He was Director of the Museum’s General and Applied Ichthyology Laboratory in Paris from 1986-2000.•The basic topics of his research dealt with teleost fish physiology, more specifically the aspects relating to spermatogenesis.
Over thirty years of topographical inventory performed by the service of Ile-de-France have permitted to acquire in-depth knowledge of this territory. Despite the pervasiveness of holiday resort ...heritage - you can find it in famous places such as Le Vésinet but also in the less conspicuous towns like Porcheville – villégiature has never been the subject of a thematic study. In Ile-de-France, the presence of elites close to the king is the decisive factor underpinning the development of the “villegiatura”. In the 18th century, “maisons de plaisance” and “maisons de campagne” are built in beautiful places, creating a long-lasting typology in three points (“eccentricity”, “simplicity” or “castle”). These characteristics pervade the 19th century without any disruption through geographical and a social extension. Planned lots, “colonies”, scattered lots yearn for the same privileged sites, parks of castle, forests and rivers. Villégiatures integrate significant elements such as belvedere, billiard room, music room, garden with artificial caves; all inherited from past centuries and integrated into urban architecture, so much that the suburban landscape is directly marked by the villégiature landscape.
A Conversation with Lynne Billard Billard, Lynne; Mukhopadhyay, Nitis
Statistical science,
02/2017, Letnik:
32, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Lynne Billard was born in Toowomba, Australia. She earned her B.Sc. (Honors I) in 1966, and a Ph.D. degree in 1969, both from the University of New South Wales, Australia. She is perhaps best known ...for her ground breaking research in the areas of HIV/AIDS and Symbolic Data Analysis. Broadly put, Professor Billard's research interests include epidemic theory, stochastic processes, sequential analysis, time series analysis and symbolic data. She has written extensively in all these areas and more through numerous fundamental contributions. She has published more than 200 research papers in some of the leading international journals including Australian Journal of Statistics, Biometrika, Journal of American Statistical Association, Journal of Applied Probability, Journal of Royal Statistical Society, Journal of Time Series Analysis, Nature, Sequential Analysis, Statistical Science, Statistics in Medicine and Stochastic Processes and Their Applications, plus book chapters in a number of acclaimed edited volumes. Professor Billard has (co-)edited or (co-)authored eight prestigious books including her authoritative text (co-authored with E. Diday), Symbolic Data Analysis: Conceptual Statistics and Data Mining (2006) published by Wiley. During the period 1969 through 1980, the career path took her to travel to University of Birmingham (U.K., 1969–1970), State University of New York at Buffalo (1971, 1974–1975), University of Waterloo (Canada, 1971–1974), Stanford University (California, 1974), Florida State University at Tallahassee (1975–1980), Naval Postgraduate School (U.S.A., 1979), University of California (Berkeley, 1979), Imperial College (1986), Isaac Newton Institute, Cambridge (1993), and other prestigious places. She had joined the Department of Statistics at Florida State University as an Associate Professor in 1975 and during 1976–1978 she served as the Associate Head there. She became a Professor at Florida State in 1980 but went on leave to visit the Department of Computer Science and Statistics at University of Georgia, Athens. She joined the same department in Georgia permanently as Professor of Statistics and Head in 1980. When the Department of Statistics was formed in Georgia under Professor Billard's leadership, she became its Professor and Head (1984–1989). Since 1992, she has held the most prestigious and coveted position, the University Professor, in the University of Georgia. She served as an Associate Editor for numerous journals including the Journal of American Statistical Association and Statistical Analysis and Data Mining. All her life, she has served extensively by holding high-level offices as well as memberships of both national and international committees at several scholarly international societies including the American Statistical Association (ASA), the Institute of Mathematical Statistics (IMS), International Biometrics Society (IBS) and Eastern North American Region (ENAR), Bernoulli Society and the International Statistical Institute (ISI). For example, Professor Billard was elected President of ENAR (1985), International Vice President (1993, 1996) and International President (1994, 1995) of IBS and President of ASA (1996). She has earned many honors and awards, including Fellow of the IMS (1988), Fellow of the ASA (1980), Fellow of the American Association for the Advancement of Science (2001) and elected membership in the ISI (1980). Professor Billard received several prestigious awards including the S. S. Wilks Medal (1999) of the ASA. Its citation read, "For significant contributions to the theory and methodology of statistics and the advancement of scientific knowledge in a variety of fields, especially in the area of HIV/AIDS; for effective leadership on issues of public interest, particularly with respect to the decennial census; for energetic professional service nationally and internationally; and for influential dedication to the statistical education of both statisticians and the public at large." She was honored by the Founders Award (2003) from the ASA. She received the Committee of Presidents of Statistical Societies (COPSS) Elizabeth Scott Award (2008) and FN David Award (2013), as well as the Janet L Norwood Award (2011). In 2015, she was installed as an Honorary Member of the Statistical Society of Slovenia. Professor Billard travels extensively to scientific conferences as an invited participant, works harder than many half her age, and continues to inspire through her writings and uniquely affectionate presence. The following conversation began August 1, 2011, at the Joint Statistical Meetings held in Miami, Florida.
We propose a generalization of a classical result on random Fourier series, namely the Billard Theorem, for random Fourier series over the
d
-dimensional torus. We provide an investigation of the ...independence with respect to a choice of a sequence of partial sums (or
method of summation
). We also study some probabilistic properties of the resulting sum field such as stationarity and characteristics of the marginal distribution.
When Australian Luke de Castro plays poolbillard, it sometimes looks like he's overriding physical rules: Bullets roll around the corner or suddenly just roll back. In his clip\ "Impossible Trick ...Shots\" he shows the whole range of his ability More than two million users have already marveled at it
Wenn der Australier Luke de Castro Poolbillard spielt, sieht es manchmal so aus, als würde er physikalische Regeln außer Kraft setzen: Kugeln rollen um die Ecke oder plötzlich einfach zurück. In seinem Clip "Impossible Trick Shots" zeigt er die ganze Bandbreite seines Könnens. Mehr als zwei Millionen User haben schon darüber gestaunt.
Malice Jean-Jacques Honegger; Jean Rose
1958
Video Recording
Ein Mann schiesst eine Billardkugel so schwungvoll über den Tisch hinaus, dass sie gleich die Treppe runter rollt. Er geht ihr nach, aber als er sie aufheben will, rollt sie wieder die Treppe hinauf ...und führt ihn daraufhin noch ein paar Mal in die Irre. Schliesslich lockt sie ihn ins Wasser.
A billiard ball plays tricks on a billiard player.
Outer billiards on kites Schwartz, Richard Evan; Schwartz, Richard Evan
2009., 20091005, 2009, 2010-01-01, Letnik:
171
eBook
Outer billiards is a basic dynamical system defined relative to a convex shape in the plane. B. H. Neumann introduced this system in the 1950s, and J. Moser popularized it as a toy model for ...celestial mechanics. All along, the so-called Moser-Neumann question has been one of the central problems in the field. This question asks whether or not one can have an outer billiards system with an unbounded orbit. The Moser-Neumann question is an idealized version of the question of whether, because of small disturbances in its orbit, the Earth can break out of its orbit and fly away from the Sun. In Outer Billiards on Kites, Richard Schwartz presents his affirmative solution to the Moser-Neumann problem. He shows that an outer billiards system can have an unbounded orbit when defined relative to any irrational kite. A kite is a quadrilateral having a diagonal that is a line of bilateral symmetry. The kite is irrational if the other diagonal divides the quadrilateral into two triangles whose areas are not rationally related. In addition to solving the basic problem, Schwartz relates outer billiards on kites to such topics as Diophantine approximation, the modular group, self-similar sets, polytope exchange maps, profinite completions of the integers, and solenoids--connections that together allow for a fairly complete analysis of the dynamical system.
Cette thèse porte sur le comportement asymptotique des systèmes dynamiques et contient cinq chapitres indépendants.Nous considérons dans la première partie de la thèse trois systèmes dynamiques ...concrets. Les deux premiers chapitres présentent deux modèles de systèmes physiques : dans le premier, nous étudions la structure géométrique des langues d'Arnold de l'équation modélisant le contact de Josephson; dans le deuxième, nous nous intéressons au problème de Lagrange de recherche de la vitesse angulaire asymptotique d'un bras articulé sur une surface. Dans le troisième chapitre nous étudions la géométrie plane du billard elliptique avec des méthodes de la géométrie complexe.Les quatrième et cinquième chapitres sont dédiés aux méthodes générales d'étude asymptotique des systèmes dynamiques. Dans le quatrième chapitre nous prouvons la convergence des moyennes sphériques pour des actions du groupe libre sur un espace mesuré. Dans le cinquième chapitre nous fournissons une forme normale pour un produit croisé qui peut s'avérer utile dans l'étude des attracteurs étranges de systèmes dynamiques.
This thesis deals with the questions of asymptotic behavior of dynamical systems and consists of six independent chapters. In the first part of this thesis we consider three particular dynamical systems. The first two chapters deal with the models of two physical systems: in the first chapter, we study the geometric structure and limit behavior of Arnold tongues of the equation modeling a Josephson contact; in the second chapter, we are interested in the Lagrange problem of establishing the asymptotic angular velocity of the swiveling arm on the surface. The third chapter deals with planar geometry of an elliptic billiard.The forth and fifth chapters are devoted to general methods of studying the asymptotic behavior of dynamical systems. In the forth chapter we prove the convergence of markovian spherical averages for free group actions on a probablility space. In the fifth chapter we provide a normal form for skew-product diffeomorphisms that can be useful in the study of strange attractors of dynamical systems.
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