On the Size Distribution of Autonomous Systems

This paper explores reasons for the high degree of variability in the sizes of ASes that have recently been observed, and the processes by which this variable distribution develops. AS size distribution is important for a number of reasons. First, when modeling network topologies, an AS size distribution assists in labeling routers with an associated AS. Second, AS size has been found to be positively correlated with the degree of the AS (number of peering links), so understanding the distribution of AS sizes has implications for AS connectivity properties. Our model accounts for AS births, growth, and mergers. We analyze two models: one incorporates only the growth of hosts and ASes, and a second extends that model to include mergers of ASes. We show analytically that, given reasonable assumptions about the nature of mergers, the resulting size distribution exhibits a power law tail with the exponent independent of the details of the merging process. We estimate parameters of the models from measurements obtained from Internet registries and from BGP tables. We then compare the models solutions to empirical AS size distribution taken from Mercator and Skitter datasets, and find that the simple growth-based model yields general agreement with empirical data. Our analysis of the model in which mergers occur in a manner independent of the size of the merging ASes suggests that more detailed analysis of merger processes is needed.

On the Emergence of Highly Variable Distributions in the Autonomous System Topology

Recent studies have noted that vertex degree in the autonomous system (AS) graph exhibits a highly variable distribution [15, 22]. The most prominent explanatory model for this phenomenon is the Barabási-Albert (B-A) model [5, 2]. A central feature of the B-A model is preferential connectivity—meaning that the likelihood a new node in a growing graph will connect to an existing node is proportional to the existing node’s degree. In this paper we ask whether a more general explanation than the B-A model, and absent the assumption of preferential connectivity, is consistent with empirical data. We are motivated by two observations: first, AS degree and AS size are highly correlated [11]; and second, highly variable AS size can arise simply through exponential growth. We construct a model incorporating exponential growth in the size of the Internet, and in the number of ASes. We then show via analysis that such a model yields a size distribution exhibiting a power-law tail. In such a model, if an AS’s link formation is roughly proportional to its size, then AS degree will also show high variability. We instantiate such a model with empirically derived estimates of growth rates and show that the resulting degree distribution is in good agreement with that of real AS graphs.

Ganz Berlin muß nach Wien, Jegen die Croaten ziehn! Dann is Windischjrätz verloren! Karbe hat es uns jeschworen: Eene Rede, jered't von Herr Karben, am 31. October, uf de Kummödientreppe, un wortjetrei abjekuppirt: Freinde! Brüder! Mitbürger! Berliner! Souveränet Volk! ...

Welsch (Projektbearbeiter): Satire auf den Werdegang der sehr weitgehenden und radikalen Forderungen der Berliner Volksredner, der immer nach demselben Muster abläuft: die Forderungen werden auf einer Volksversammlung vom Redner formuliert und von der Versammlung gutgeheißen. Darauf wird eine Deputation gebildet, die die fraglichen Forderungen der Nationalversammlung als Petition übergibt. Nach dem Empfang der Deputation durch die Nationalversammlung macht sich der Abgeordnete D'Ester die Petition zu eigen und übergibt sie dem Präsidenten, der sie in die Kommissionen verweist. Die Kommissionen wiederum beraten darüber und erstatten am nächsten Tag Bericht. "Un so war et, un so is et, un so wird et bleiben." Geschildert vor dem Hintergrund der Niederschlagung der Wiener Revolution am Beispiel einer - fiktiven - Rede von Adolph Friedrich Karbe

ETO, fusion partner in t(8;21) acute myeloid leukemia, represses transcription by interaction with the human N-CoR/mSin3/HDAC1 complex

The t(8;21) translocation between two genes known as AML1 and ETO is seen in approximately 12–15% of all acute myeloid leukemia (AML) and is the second-most-frequently observed nonrandom genetic alteration associated with AML. AML1 up-regulates a number of target genes critical to normal hematopoiesis, whereas the AML1/ETO fusion interferes with this trans-activation. We discovered that the fusion partner ETO binds to the human homolog of the murine nuclear receptor corepressor (N-CoR). The interaction is mediated by two unusual zinc finger motifs present at the carboxyl terminus of ETO. Human N-CoR (HuN-CoR), which we cloned and sequenced in its entirety, encodes a 2,440-amino acid polypeptide and has a central domain that binds ETO. N-CoR, mammalian Sin3 (mSin3A and B), and histone deacetylase 1 (HDAC1) form a complex that alters chromatin structure and mediates transcriptional repression by nuclear receptors and by a number of oncoregulatory proteins. We found that ETO, through its interaction with the N-CoR/mSin3/HDAC1 complex, is also a potent repressor of transcription. This observation provides a mechanism for how the AML1/ETO fusion may inhibit expression of AML1-responsive target genes and disturb normal hematopoiesis.

University of Michigan Football Team, 1901

Top Row: Wesley Winkler, Ralph Drake, Charles Rothschild, Norman Sterry, Kenneth Robinson, Alfred Chadwick, Weldon Fix, Ross Kidston, Les Barkenbus, Harrison Weeks, David Dunlap, George Gregory, Harold Baker, Cecil Gooding, George Sadler

Third Row: student mngr. H.C. Crafts, Edward Dickey(?), David Beardsley, William Snushall, ? Smith, George Davison, Kennedy Potter, ? Clark, Charles Van Valkenberg, Neil Snow, Joseph Horgan, James Forrest, William Foote, Webb Sadler, ? Hayes

Second Row: trainer Keene Fitzpatrick, ? Smith, Samuel Sackett, Everett Sweeley, Herbert Graver, Walter Shaw, Hugh White, Albert Herrnstein, Curtis Redden, Dan McGugin, Ebin Wilson, Bruce Shorts, Arthur Redner, Temple Owens

Front Row: Ralph Husson, Albert Preussman, Arthur Urquhart, Willie Heston, Benjamin Southworth, coach Fielding Yost, Charles Crane, Jerome (mascot), John Lewis, Frank Doty, Frank Belknap

1900 University of Michigan Football Team

1901 University of Michigan Football Team

1901 University of Michigan Football Team

1954 University of Michigan Men's Golf Team

Back Row: Coach Bert Katzenmeyer, captain Jack Stumfig, Charles Blackett, Richard Harrison, Thad Stanford, Robert McMasters.

Front Row: Boyd Redner, Harold Andrews

Großbritannien nach der Europa-Wahl:Abkehr von Europa, Abkehr vom Vereinigten Königreich?

Die britische Politik wird gerade jetzt aufmerksam von anderen europäischen Ländern verfolgt. Die britischen Wähler/innen schicken den Rechtspopulisten Nigel Farage wieder nach Brüssel. Er gilt als unterhaltsamer und charismatischer Redner, sein Markenzeichen ist das Pint Beer in der Hand. Die britischen Parteien zeigen sich derzeit oft skeptisch gegenüber der EU: seien es Labour-Vertreter, die alles andere als Begeisterung bei der Aufstellung des Spitzenkandidaten Martin Schulz zeigten, oder die Tories, die eine Volksabstimmung über den Europa-Austritt im Jahr 2017 im Falle eines Wahlsieges im Jahr 2015 angekündigt haben und in der Zwischenzeit so tun, als wären sie wirklich lieber schon draußen. Zu dem schwierigen Verhältnis zu Europa kommt derzeit noch die brisante innenpolitische Situation mit dem möglichen Austritt von Schottland aus dem Vereinigten Königreich hinzu. Die Schotten stimmen in einer Volksabstimmung im September 2014 ab, der Ausgang wird derzeit laut Umfragen immer knapper.