283 research outputs found

    An Analytical Overview of Urban Information Systems in the United States

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    Urban governments are becoming increasingly interested in modern management techniques such as computerized information systems. This paper presents an analytical state-of-the-art review of the uses, impacts and problems of computer technology in local governments in the United States. It reports the results of a questionnaire survey conducted by URBIS (Urban Information System) Research Group, University of California at Irvine to determine the uses of computer technology and the policies governing those uses within local governments. The organization and research strategy of the URBIS Project is presented by way of introduction and is followed by a discussion of the role IIASA might play in the study of Urban Information Systems

    Taking Cooperative Decisions in Group-Based Wireless Sensor Networks

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    Several studies have demonstrated that communications are more efficient when cooperative group-based architectures are used in wireless sensor networks (WSN). This type of architecture allows increasing sensor nodes' lifetime by decreasing the number of messages in network. But, the main gap is to know how to take cooperative decisions in order to make the right communication. In this paper, we analyze the main aspects related to collaborative decisions in WSNs. A mathematical analysis will be presented in order to take the correct decision. Finally, the simulations will show the efficiency of the method used to make cooperative decisions in WSNs. © 2011 Springer-Verlag.GarcĂ­a Pineda, M.; Lloret, J.; Sendra Compte, S.; Rodrigues, JJPC. (2011). Taking Cooperative Decisions in Group-Based Wireless Sensor Networks. En Lecture Notes in Computer Science. Springer Verlag (Germany). 61-65. doi:10.1007/978-3-642-23734-8_9S6165Garcia, M., Bri, D., Sendra, S., Lloret, J.: Practical Deployments of Wireless Sensor Networks: a Survey. Int. Journal on Advances in Networks and Services 3(3-4), 170–185 (2010)Lloret, J., Garcia, M., Tomas, J.: Improving Mobile and Ad-hoc Networks performance using Group-Based Topologies. In: Wireless Sensor and Actor Networks II. IFIP, vol. 264, pp. 209–220 (2008)Garcia, M., Lloret, J.: A Cooperative Group-Based Sensor Network for Environmental Monitoring. In: Luo, Y. (ed.) CDVE 2009. LNCS, vol. 5738, pp. 276–279. Springer, Heidelberg (2009)Garcia, M., Sendra, S., Lloret, J., Lacuesta, R.: Saving Energy with Cooperative Group-Based Wireless Sensor Networks. In: Luo, Y. (ed.) CDVE 2010. LNCS, vol. 6240, pp. 73–76. Springer, Heidelberg (2010)Parsa, S., Parand, F.-A.: Cooperative decision making in a knowledge grid environment. Future Generation Computer Systems 23, 932–938 (2007)Soubie, J.-L., ZaratĂ©, P.: Distributed Decision Making: A Proposal of Support Through Cooperative Systems. J. Group Decisions and Negotiation 14(2), 147–158 (2005)Kraemer, K.L., King, J.L.: Computer-based systems for cooperative work and group decision making. ACM Computer Survey 20(2), 115–146 (1988)Kernan, J.B.: Choice Criteria, Decision Behavior, and Personality. Journal of Marketing Research 5(2), 155–164 (1968

    Measurement of W Polarisation at LEP

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    The three different helicity states of W bosons produced in the reaction e+ e- -> W+ W- -> l nu q q~ at LEP are studied using leptonic and hadronic W decays. Data at centre-of-mass energies \sqrt s = 183-209 GeV are used to measure the polarisation of W bosons, and its dependence on the W boson production angle. The fraction of longitudinally polarised W bosons is measured to be 0.218 \pm 0.027 \pm 0.016 where the first uncertainty is statistical and the second systematic, in agreement with the Standard Model expectation

    Search for Anomalous Couplings in the Higgs Sector at LEP

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    Anomalous couplings of the Higgs boson are searched for through the processes e^+ e^- -> H gamma, e^+ e^- -> e^+ e^- H and e^+ e^- -> HZ. The mass range 70 GeV < m_H < 190 GeV is explored using 602 pb^-1 of integrated luminosity collected with the L3 detector at LEP at centre-of-mass energies sqrt(s)=189-209 GeV. The Higgs decay channels H -> ffbar, H -> gamma gamma, H -> Z\gamma and H -> WW^(*) are considered and no evidence is found for anomalous Higgs production or decay. Limits on the anomalous couplings d, db, Delta(g1z), Delta(kappa_gamma) and xi^2 are derived as well as limits on the H -> gamma gamma and H -> Z gamma decay rates

    Measurement of W Polarisation at LEP

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    The three different helicity states of W bosons produced in the reaction e+ e- -> W+ W- -> l nu q q~ at LEP are studied using leptonic and hadronic W decays. Data at centre-of-mass energies \sqrt s = 183-209 GeV are used to measure the polarisation of W bosons, and its dependence on the W boson production angle. The fraction of longitudinally polarised W bosons is measured to be 0.218 \pm 0.027 \pm 0.016 where the first uncertainty is statistical and the second systematic, in agreement with the Standard Model expectation

    Neutral-Current Four-Fermion Production in e+e- Interactions at LEP

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    Neutral-current four-fermion production, e+e- -> ffff is studied in 0.7/fb of data collected with the L3 detector at LEP at centre-of-mass energies root(s)=183-209GeV. Four final states are considered: qqvv, qqll, llll and llvv, where l denotes either an electron or a muon. Their cross sections are measured and found to agree with the Standard Model predictions. In addition, the e+e- -> Zgamma* -> ffff process is studied and its total cross section at the average centre-of-mass energy 196.6GeV is found to be 0.29 +/- 0.05 +/- 0.03 pb, where the first uncertainty is statistical and the second systematic, in agreement with the Standard Model prediction of 0.22 pb. Finally, the mass spectra of the qqll final states are analysed to search for the possible production of a new neutral heavy particle, for which no evidence is found

    Measurement of Exclusive rho+rho- Production in Mid-Virtuality Two-Photon Interactions and Study of the gamma gamma* -> rho rho Process at LEP

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    Exclusive rho+rho- production in two-photon collisions between a quasi-real photon, gamma, and a mid-virtuality photon, gamma*, is studied with data collected at LEP at centre-of-mass energies root(s)=183-209GeV with a total integrated luminosity of 684.8pb^-1. The cross section of the gamma gamma* -> rho+ rho- process is determined as a function of the photon virtuality, Q^2, and the two-photon centre-of-mass energy, W_gg, in the kinematic region: 0.2GeV^2 < Q^2 <0.85GeV^2 and 1.1GeV < W_gg < 3GeV. These results, together with previous L3 measurements of rho0 rho0 and rho+ rho- production, allow a study of the gamma gamma* -> rho rho process over the Q^2-region 0.2GeV^2 < Q^2 < 30 GeV^2

    Bose-Einstein Correlations of Neutral and Charged Pions in Hadronic Z Decays

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    Bose-Einstein correlations of both neutral and like-sign charged pion pairs are measured in a sample of 2 million hadronic Z decays collected with the L3 detector at LEP. The analysis is performed in the four-momentum difference range 300 MeV < Q < 2 GeV. The radius of the neutral pion source is found to be smaller than that of charged pions. This result is in qualitative agreement with the string fragmentation model

    Z Boson Pair-Production at LEP

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    Events stemming from the pair-production of Z bosons in e^+e^- collisions are studied using 217.4 pb^-1 of data collected with the L3 detector at centre-of-mass energies from 200 GeV up to 209 GeV. The special case of events with b quarks is also investigated. Combining these events with those collected at lower centre-of-mass energies, the Standard Model predictions for the production mechanism are verified. In addition, limits are set on anomalous couplings of neutral gauge bosons and on effects of extra space dimensions

    Measurement of the Running of the Electromagnetic Coupling at Large Momentum-Transfer at LEP

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    The evolution of the electromagnetic coupling, alpha, in the momentum-transfer range 1800GeV^2 < -Q^2 < 21600GeV^2 is studied with about 40000 Bhabha-scattering events collected with the L3 detector at LEP at centre-of-mass energies 189-209GeV. The running of alpha is parametrised as: alpha(Q^2) = alpha_0/(1-C Delta alpha(Q^2)), where alpha_0=\alpha(Q^2=0) is the fine-structure constant and C=1 corresponds to the evolution expected in QED. A fit to the differential cross section of the e+e- ->e+e- process for scattering angles in the range |cos theta|<0.9 excludes the hypothesis of a constant value of alpha, C=0, and validates the QED prediction with the result: C = 1.05 +/- 0.07 +/- 0.14, where the first uncertainty is statistical and the second systematic
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