144 research outputs found

    Integrating business-to-business customers in original equipment manufacturers’ supply chains through information systems integration

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    Original equipment manufacturers (OEMs) are increasingly being urged to integrate their business-to-business customers into their supply chain. This involves integrating the information systems of the OEM’s supply chain with those of the customers. However, the literature has little to say about what it takes to integrate the information systems of OEMs’ supply chain and business customers. This paper develops a framework that identifies different levels of integration of business customers’ information systems with those of the OEM’s supply chain. It then discusses how this integration affects market performance and strategic gains that accrue to the chain. However, if such systems are integrated without appropriate conditions within and outside the OEM’s supply chain, it may not be possible to actualise the potential of such integration. Therefore, we also identify and examine how a variety of contextual factors moderate the effectiveness of customers’ systems integration in a supply chain.info:eu-repo/semantics/publishedVersio

    A Model for Using the Internet and the Web Technologies for New Product Development

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    Recent developments in Internet technology and the World Wide Web have the potential of making the product development process truly integrated, simultaneous, flexible, and responsive. However, little is known about how the Web can be effectively used for new product development. Based on the premise that Internet technology can be an agent of enterprise information integration, information enabled organization, and customer responsiveness, we develop a reference model which lays out the scope and benefits of using the Web for new product development. We also develop an implementation framework that informs product development managers about a variety of Web technologies that can be used for Web-based product development

    Duality and Non-Commutative Gauge Theory

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    We study the generalization of S-duality to non-commutative gauge theories. For rank one theories, we obtain the leading terms of the dual theory by Legendre transforming the Lagrangian of the non-commutative theory expressed in terms of a commutative gauge field. The dual description is weakly coupled when the original theory is strongly coupled if we appropriately scale the non-commutativity parameter. However, the dual theory appears to be non-commutative in space-time when the original theory is non-commutative in space. This suggests that locality in time for non-commutative theories is an artifact of perturbation theory.Comment: 7 pages, harvmac; a typo fixe

    Pinned Branes and New Non Lorentz Invariant Theories

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    We describe a mechanism for localising branes in ambient space. When a 3-form flux is turned on in a Taub-NUT space, an M5-brane gets an effective potential that pins it to the center of the space. A similar effect occurs for M2-branes and D-branes with appropriate fluxes. In carefully chosen limits of the external parameters, this leads to new theories that are decoupled from gravity and appear to break Lorentz invariance. For example, we predict the existence of a new 5+1D theory that breaks Lorentz invariance at high-energy and has a low-energy description of N tensor multiplets with (1,0) supersymmetry. We also predict a new type of theory that, similarly to the little-string theory decouples from gravity by a dynamical (rather than kinematical) argument.Comment: 29pp LaTeX, formulas in section 7 corrected, ref added, final version to appear in Nucl. Phys.

    Tangled magnetic fields and CMBR signal from reionization epoch

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    We compute the secondary CMBR anisotropy signal from the reionization of the universe in the presence of tangled magnetic fields. We consider the tangled magnetic-field-induced scalar, vector, and tensor modes for our analysis. The most interesting signal for l<10 arise from tensor perturbations. In particular, we show that the enhancement observed by WMAP in the TE cross-correlation signal for l<10 could be explained by tensor TE cross-correlation from tangled magnetic fields generated during the inflationary epoch for magnetic field strength B_0=4.5*10^{-9}G and magnetic field power spectrum spectral index n=-2.9. Alternatively, a mixture of tensor mode signal with primordial scalar modes give weaker bounds on the value of the optical depth to the reionization surface, tau_{reion}=0.11 +/- 0.02. This analysis can also be translated to a limit on the magnetic field strength of nearly 5*10{-9}G for wave-numbers < 0.05 Mpc^{-1}Comment: 28 pages, 6 figures, submitted to Physical Review

    Time-Dependent Warping, Fluxes, and NCYM

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    We describe the supergravity solutions dual to D6-branes with both time-dependent and time-independent B-fields. These backgrounds generalize the Taub-NUT metric in two key ways: they have asymmetric warp factors and background fluxes. In the time-dependent case, the warping takes a novel form. Kaluza-Klein reduction in these backgrounds is unusual, and we explore some of the new features. In particular, we describe how a localized gauge-field emerges with an analogue of the open string metric and coupling. We also describe a gravitational analogue of the Seiberg-Witten map. This provides a framework in supergravity both for studying non-commutative gauge theories, and for constructing novel warped backgrounds.Comment: 32 pages, LaTeX, references adde

    Duality in Heterotic Vacua With Four Supercharges

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    We study heterotic vacua with four supercharges in three and four space-time dimensions and their duals obtained as M/F-theory compactified on Calabi-Yau fourfolds. We focus on their respective moduli spaces and derive the Kahler potential for heterotic vacua obtained as circle compactifications of four-dimensional N=1 heterotic theories. The Kahler potential of the dual theory is computed by compactifying 11-dimensional supergravity on Calabi-Yau fourfolds. The duality between these theories is checked for K3-fibred fourfolds and an appropriate F-theory limit is discussed.Comment: 28 pages, LaTe

    Five-Brane Superpotentials and Heterotic/F-theory Duality

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    Under heterotic/F-theory duality it was argued that a wide class of heterotic five-branes is mapped into the geometry of an F-theory compactification manifold. In four-dimensional compactifications this identifies a five-brane wrapped on a curve in the base of an elliptically fibered Calabi-Yau threefold with a specific F-theory Calabi-Yau fourfold containing the blow-up of the five-brane curve. We argue that this duality can be reformulated by first constructing a non-Calabi-Yau heterotic threefold by blowing up the curve of the five-brane into a divisor with five-brane flux. Employing heterotic/F-theory duality this leads us to the construction of a Calabi-Yau fourfold and four-form flux. Moreover, we obtain an explicit map between the five-brane superpotential and an F-theory flux superpotential. The map of the open-closed deformation problem of a five-brane in a compact Calabi-Yau threefold into a deformation problem of complex structures on a dual Calabi-Yau fourfold with four-form flux provides a powerful tool to explicitly compute the five-brane superpotential.Comment: 43 pages, v2: minor correction

    Proton Decay, Yukawa Couplings and Underlying Gauge Symmetry in String Theory

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    In string theory, massless particles often originate from a symmetry breaking of a large gauge symmetry G to its subgroup H. The absence of dimension-4 proton decay in supersymmetric theories suggests that (\bar{D},L) are different from \bar{H}(\bar{\bf 5}) in their origins. In this article, we consider a possibility that they come from different irreducible components in g/h\mathfrak{g}/\mathfrak{h}. Requiring that all the Yukawa coupling constants of quarks and leptons be generated from the super Yang--Mills interactions of G, we found in the context of Georgi--Glashow H=SU(5) unification that the minimal choice of G is E_7 and E_8 is the only alternative. This idea is systematically implemented in Heterotic String, M theory and F theory, confirming the absence of dimension 4 proton decay operators. Not only H=SU(5) but also G constrain operators of effective field theories, providing non-trivial information.Comment: 73 page
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