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To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ejor.2006.06.055 Byline: Kaushik Dutta (a), Debra VanderMeer (a), Anindya Datta (b)(c), Pinar Keskinocak (d), Krithi Ramamritham (e) Keywords: Data mining; e-Commerce; Graph theory; Applied probability Abstract: Web sites allow the collection of vast amounts of navigational data - clickstreams of user traversals through the site. These massive data stores offer the tantalizing possibility of uncovering interesting patterns within the dataset. For e-businesses, always looking for an edge in the hyper-competitive online marketplace, the discovery of critical edge sequences (CESs), which denote frequently traversed sequences in the catalog, is of significant interest. CESs can be used to improve site performance and site management, increase the effectiveness of advertising on the site, and gather additional knowledge of customer behavior patterns on the site. Using web mining strategies to find CESs turns out to be expensive in both space and time. In this paper, we propose an approximate algorithm to compute the most popular traversal sequences between node pairs in a catalog, which are then used to discover CESs. Our method is both fast and space efficient, providing a vast reduction in both the run time and storage requirements, with minimum impact on accuracy. Author Affiliation: (a) Department of Decision Sciences and Information Systems, Florida International University, Miami, Florida 33199, United States (b) Walking Stick Solutions, 75 Fifth Street NW, Suite 218, Atlanta, Georgia 30308, United States (c) School of Information Systems, Singapore Management University, 80 Stamford Rd, Singapore 178902 (d) School of Industrial and Systems Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States (e) Department of Computer Science and Engineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India Article History: Received 23 July 2005; Accepted 30 June 2006 Article Note: (footnote) [star] An early version of this work appeared in the ACM Conference on Electronic Commerce, 2001.

This paper reports large eddy simulations (LES) of a premixed turbulent round methane-air jet flame at an equivalence ratio of 0.8 and unburnt gas temperature of 800 K using the explicit filtering LES (EFLES) method. The nominal 1D premixed flame speed, s L = 2.05 ms − 1 and thermal thickness, δ L = 300 μ m. EFLES is formally derived from the approximate deconvolution method for LES computations. The nominal turbulent Reynolds number R e t = 34 and the turbulent Karlovitz number K a = 25 places the present flame in the thin reaction zones regime of turbulent premixed combustion. LES and DNS results are obtained by solving species transport equations using a reduced 13-species chemical mechanism. Chemical source terms in the LES are computed using resolved species and temperature fields in all simulations. Conditional means of net heat release rate predicted by the LES and DNS show excellent agreement. The LES results show a marginally thicker flame brush and a shorter mean flame height when compared to the DNS results. Good agreement between LES and DNS for mean quantities is seen upstream of the tip. Larger quantitative differences are seen at the tip due to the difference in flame height between LES and DNS cases, as may be expected. Even at these positions, qualitative features of the DNS results and peak mean values are recovered correctly. Agreement between conditional mean statistics from both LES and DNS is good. RMS fluctuation amplitudes show larger quantitative differences between LES and DNS when compared to mean statistics while still capturing the correct qualitative features of the DNS profiles. The radial profiles of unconditioned RMS fluctuations are broader by O (δ L) in the LES results, with increasing downstream distance. The smaller range of resolved scales in the LES causes the resolved flow motions to be more energetic resulting in increased turbulent transport rates for mean and RMS quantities. This results in the observed broadening of flow statistics in the LES when compared to the DNS. With mesh refinement, differences between LES and DNS results for all statistics are found to diminish smoothly. [ABSTRACT FROM AUTHOR]

Abstract: Besides supersymmetry, the other prime candidate of physics beyond the Standard Model (SM), crying out for verification at the CERN Large Hadron Collider (LHC), is extra-dimension. To hunt for effects of Kaluza–Klein (KK) excitations of known fermions and bosons is very much in the agenda of the LHC. These KK states arise when the SM particles penetrate in the extra space-like dimension(s). In this paper, we consider a 5d scenario, called ‘Universal Extra Dimension’, where the extra space coordinate, compactified on an orbifold , is accessed by all the particles. The KK number (n) is conserved at all tree level vertices. This entails the production of KK states in pairs and renders the lightest KK particle stable, which leaves the detector carrying away missing energy. The splitting between different KK flavors is controlled by the zero mode masses and the bulk- and brane-induced one-loop radiative corrections. We concentrate on the production of an KK electroweak gauge boson in association with an KK quark. This leads to a signal consisting of only one jet, one or more leptons and missing . For definiteness we usually choose the inverse radius of compactification to be , which sets the scale of the lowest lying KK states. We show on a case-by-case basis (depending on the number of leptons in the final state) that with 10 fb−1 integrated luminosity at the LHC with this signal can be detected over the SM background by imposing appropriate kinematic cuts. We record some of the expectations for a possible intermediate LHC run at and also exhibit the integrated luminosity required to obtain a 5σ signal as a function of . [Copyright &y& Elsevier]

Abstract: We discuss the phenomenology of -mode adjoint scalars in the framework of two Universal Extra Dimensions. The Kaluza–Klein (KK) towers of these adjoint scalars arise in the 4-dimensional effective theory from the 6th component of the gauge fields after compactification. Adjoint scalars can have KK-number conserving as well as KK-number violating interactions. We calculate the KK-number violating operators involving these scalars and two Standard Model fields. Decay widths of these scalars into different channels have been estimated. We have also briefly discussed pair-production and single production of such scalars at the Large Hadron Collider. [Copyright &y& Elsevier]

Abstract: We study the power law running of gauge, Yukawa and quartic scalar couplings in the universal extra dimension scenario where the extra dimension is accessed by all the standard model fields. After compactifying on an orbifold, we compute one-loop contributions of the relevant Kaluza–Klein (KK) towers to the above couplings up to a cutoff scale Λ. Beyond the scale of inverse radius, once the KK states are excited, these couplings exhibit power law dependence on Λ. As a result of faster running, the gauge couplings tend to unify at a relatively low scale, and we choose our cutoff also around that scale. For example, for a radius , the cutoff is around 30 TeV. We then examine the consequences of power law running on the triviality and vacuum stability bounds on the Higgs mass. We also comment that the supersymmetric extension of the scenario requires to be larger than in order that the gauge couplings remain perturbative up to the scale where they tend to unify. [Copyright &y& Elsevier]

We argue that the ZZH coupling constitutes a simple probe of the nature of the scalar sector responsible for electroweak symmetry breaking. We demonstrate the efficacy of this measure through an analysis of four-dimensional models containing scalars in arbitrary representation of SU(2)×U(1), as well as extra-dimensional models with a non-factorizable geometry. A possible role for the tt¯H couplings is also discussed. [Copyright &y& Elsevier]