61 research outputs found
Scoring dynamics across professional team sports: tempo, balance and predictability
Despite growing interest in quantifying and modeling the scoring dynamics
within professional sports games, relative little is known about what patterns
or principles, if any, cut across different sports. Using a comprehensive data
set of scoring events in nearly a dozen consecutive seasons of college and
professional (American) football, professional hockey, and professional
basketball, we identify several common patterns in scoring dynamics. Across
these sports, scoring tempo---when scoring events occur---closely follows a
common Poisson process, with a sport-specific rate. Similarly, scoring
balance---how often a team wins an event---follows a common Bernoulli process,
with a parameter that effectively varies with the size of the lead. Combining
these processes within a generative model of gameplay, we find they both
reproduce the observed dynamics in all four sports and accurately predict game
outcomes. These results demonstrate common dynamical patterns underlying
within-game scoring dynamics across professional team sports, and suggest
specific mechanisms for driving them. We close with a brief discussion of the
implications of our results for several popular hypotheses about sports
dynamics.Comment: 18 pages, 8 figures, 4 tables, 2 appendice
Detecting Friendship Within Dynamic Online Interaction Networks
In many complex social systems, the timing and frequency of interactions
between individuals are observable but friendship ties are hidden. Recovering
these hidden ties, particularly for casual users who are relatively less
active, would enable a wide variety of friendship-aware applications in domains
where labeled data are often unavailable, including online advertising and
national security. Here, we investigate the accuracy of multiple statistical
features, based either purely on temporal interaction patterns or on the
cooperative nature of the interactions, for automatically extracting latent
social ties. Using self-reported friendship and non-friendship labels derived
from an anonymous online survey, we learn highly accurate predictors for
recovering hidden friendships within a massive online data set encompassing 18
billion interactions among 17 million individuals of the popular online game
Halo: Reach. We find that the accuracy of many features improves as more data
accumulates, and cooperative features are generally reliable. However,
periodicities in interaction time series are sufficient to correctly classify
95% of ties, even for casual users. These results clarify the nature of
friendship in online social environments and suggest new opportunities and new
privacy concerns for friendship-aware applications that do not require the
disclosure of private friendship information.Comment: To Appear at the 7th International AAAI Conference on Weblogs and
Social Media (ICWSM '13), 11 pages, 1 table, 6 figure
Heat-Labile Enterotoxin: Beyond GM1 Binding
Enterotoxigenic Escherichia coli (ETEC) is a significant source of morbidity and mortality worldwide. One major virulence factor released by ETEC is the heat-labile enterotoxin LT, which is structurally and functionally similar to cholera toxin. LT consists of five B subunits carrying a single catalytically active A subunit. LTB binds the monosialoganglioside GM1, the toxinβs host receptor, but interactions with A-type blood sugars and E. coli lipopolysaccharide have also been identified within the past decade. Here, we review the regulation, assembly, and binding properties of the LT B-subunit pentamer and discuss the possible roles of its numerous molecular interactions
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Dynamics and Structure in Competitive Social Systems
Competition is ubiquitous in complex social systems, from informal online gaming environments to professional sports, to workers competing for jobs in the labor market. Given its universality, understanding the complex relationships between a competition\u27s dynamics, competitor behavior, and environmental structure is of great interest to the scientific community and society at large. In this thesis, we analyze the structure of and behav- ioral dynamics in three different competitive social systems: a massive online game, four professional sports, and a network of occupations. Our results shed new light on how a competition\u27s environment can predict its dynamics, what types of temporal and pro-social behaviors are indicative of friendship between competitors, how those friendships evolve over time, and how the structural properties of an occupation network inform career path decisions and forecast the long term distribution of incomes in an economy
Crossed-Field Sampling of Picosecond Optical Signals
127 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1978.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD
Two-way TCP Connections: Old Problem, New Insight
International audienceMany papers explain the drop of download performance when two TCP connections in opposite directions share a common bottleneck link by ACK compression, the phenomenon in which download ACKs arrive in bursts so that TCP self clocking breaks. Efficient mechanisms to cope with the performance problem exist and we do not consider proposing yet another solution. We rather thoroughly analyze the interactions between connections and show that actually ACK compression only arises in a perfectly symmetrical setup and it has little impact on performance. We provide a different explanation of the interactions---data pendulum, a core phenomenon that we analyze in this paper. In the data pendulum effect, data and ACK segments alternately fill only one of the link buffers (on the upload or download side) at a time, but almost never both of them. We analyze the effect in the case in which buffers are structured as arrays of bytes and derive an expression for the ratio between the download and upload throughput. Simulation results and measurements confirm our analysis and show how appropriate buffer sizing alleviates performance degradation. We also consider the case of buffers structured as arrays of packets and show that it amplifies the effects of data pendulum
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