268,632 research outputs found

    Tag-Cloud Drawing: Algorithms for Cloud Visualization

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    Tag clouds provide an aggregate of tag-usage statistics. They are typically sent as in-line HTML to browsers. However, display mechanisms suited for ordinary text are not ideal for tags, because font sizes may vary widely on a line. As well, the typical layout does not account for relationships that may be known between tags. This paper presents models and algorithms to improve the display of tag clouds that consist of in-line HTML, as well as algorithms that use nested tables to achieve a more general 2-dimensional layout in which tag relationships are considered. The first algorithms leverage prior work in typesetting and rectangle packing, whereas the second group of algorithms leverage prior work in Electronic Design Automation. Experiments show our algorithms can be efficiently implemented and perform well.Comment: To appear in proceedings of Tagging and Metadata for Social Information Organization (WWW 2007

    Recommending Items in Social Tagging Systems Using Tag and Time Information

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    In this work we present a novel item recommendation approach that aims at improving Collaborative Filtering (CF) in social tagging systems using the information about tags and time. Our algorithm follows a two-step approach, where in the first step a potentially interesting candidate item-set is found using user-based CF and in the second step this candidate item-set is ranked using item-based CF. Within this ranking step we integrate the information of tag usage and time using the Base-Level Learning (BLL) equation coming from human memory theory that is used to determine the reuse-probability of words and tags using a power-law forgetting function. As the results of our extensive evaluation conducted on data-sets gathered from three social tagging systems (BibSonomy, CiteULike and MovieLens) show, the usage of tag-based and time information via the BLL equation also helps to improve the ranking and recommendation process of items and thus, can be used to realize an effective item recommender that outperforms two alternative algorithms which also exploit time and tag-based information.Comment: 6 pages, 2 tables, 9 figure

    Central area fisheries annual report 1994

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    The purpose of this report is to record key events/data and to outline the activities of the NRA Central Area Fisheries Function during 1994. The Rivers looked at include the Ribble, Lune, Hodder and Wyre. The issues that the report looks at includes Hydrological and meterological data, catch data for salmon and sea trout, fish kills, and fish stocking. It also lists the Micro-tag returns for 1994 and the six key objectives that the Central Area Fisheries Function has set itself for 1995. The report uses a range of different graphs and tables to display their data

    Precision Predictions for (Un)Stable WW/4f Production in e +e- Annihilation: YFSWW3/KoralW-1.42/YFSZZ

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    We present precision calculations of the processes e+ e- -> 4-fermions in which the double resonant W+ W- and ZZ intermediate states occur. Referring to these latter intermediate states as the 'signal processes', we show that, by using the YFS Monte Carlo event generators YFSWW3-1.14 and KoralW-1.42 in an appropriate combination, we achieve a physical precision on the WW signal process, as isolated with LEP2 MC Workshop cuts, below 0.5 per cent. We stress the full gauge invariance of our calculations and we compare our results with those of other authors where appropriate. In particular, sample Monte Carlo data are explicitly illustrated and compared with the results of the program RacoonWW of Denner et al. In this way, we cross check that the total (physical oplus technical) precision tag for the WW signal process cross section is 0.4 per cent for 200 GeV, for example. Results are also given for 500 GeV with an eye toward the LC. For the analogous ZZ case, we cross check that our YFSZZ calculation yields a total precision tag of 2 per cent, when it is compared to the results of ZZTO and GENTLE of Passarino and Bardin et al., respectively.Comment: 14 pages, 1 figure, 4 tables, presented at RADCOR2000 by B.F.L. War

    Two-loop contribution to the pion transition form factor vs. experimental data

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    We present predictions for the pion-photon transition form factor, derived with the help of light-cone sum rules and including the main part of the NNLO radiative corrections. We show that, when the Bakulev-Mikhailov-Stefanis (BMS) pion distribution amplitude is used, the obtained predictions agree well with the CELLO and the CLEO data. We found that no model distribution amplitude can reproduce the observed Q2Q^2 growth of the new BaBar data, though the BMS model complies with several BaBar data points.Comment: 5 pages, 2 figures, 3 tables. Presented by the first author at 3rd joint International HADRON STRUCTURE'09 Conference at Tatranska Strba, Slovakia, August 30th - September 3rd, 2009. v2 Eqs. (9), (10) corrected; wrong reference tag removed. v3 Fig. 2 and Ref. [13] correcte

    Pion transition form factor at the two-loop level vis-\`a-vis experimental data

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    We use light-cone QCD sum rules to calculate the pion-photon transition form factor, taking into account radiative corrections up to the next-to-next-to-leading order of perturbation theory. We compare the obtained predictions with all available experimental data from the CELLO, CLEO, and the BaBar Collaborations. We point out that the BaBar data are incompatible with the convolution scheme of QCD, on which our predictions are based, and can possibly be explained only with a violation of the factorization theorem. We pull together recent theoretical results and comment on their significance.Comment: 10 pages, 4 figures, 3 tables. Presented by the first author at Workshop "Recent Advances in Perturbative QCD and Hadronic Physics", 20--25 July 2009, ECT*, Trento (Italy), in Honor of Prof. Anatoly Efremov's 75th Birthday. v2 wrong reference tag removed. v3 Fig. 4 and Ref. [27] correcte

    Study of π0\pi^0 pair production in single-tag two-photon collisions

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    We report a measurement of the differential cross section of π0\pi^0 pair production in single-tag two-photon collisions, γγπ0π0\gamma^* \gamma \to \pi^0 \pi^0, in e+ee^+ e^- scattering. The cross section is measured for Q2Q^2 up to 30 GeV2^2, where Q2Q^2 is the negative of the invariant mass squared of the tagged photon, in the kinematic range 0.5 GeV < W < 2.1 GeV and cosθ|\cos \theta^*| < 1.0 for the total energy and pion scattering angle, respectively, in the γγ\gamma^* \gamma center-of-mass system. The results are based on a data sample of 759 fb1^{-1} collected with the Belle detector at the KEKB asymmetric-energy e+ee^+ e^- collider. The transition form factor of the f0(980)f_0(980) and that of the f2(1270)f_2(1270) with the helicity-0, -1, and -2 components separately are measured for the first time and are compared with theoretical calculations.Comment: 36 pages, 37 figures, 11 tables, Belle Preprint 2015-15, KEK Preprint 2015-2

    Overview of the Path to 0.01%\% Theoretical Luminosity Precision for the FCCee and Its Possible Synergistic Effects for Other FCC Precision Theory Requirements

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    To exploit properly the precision physics program at the FCC-ee, the theoretical precision tag on the respective luminosity will need to be improved from the 0.054%\% (0.061%\%) results at LEP to 0.01%\%, where the former (latter) LEP result has (does not have) the pairs correction. We present an overview of the roads one may take to reach the required 0.01%\% precision tag at the FCC-ee and we discuss possible synergistic effects of the walk along these roads for other FCC precision theory requirements.Comment: 6 pages, 3 tables, presented by B.F.L. Ward at ICHEP2020, Prague, CZ, July 29, 2020. arXiv admin note: substantial text overlap with arXiv:1902.0591
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