820 research outputs found

    Brascamp-Lieb Inequality and Its Reverse: An Information Theoretic View

    Full text link
    We generalize a result by Carlen and Cordero-Erausquin on the equivalence between the Brascamp-Lieb inequality and the subadditivity of relative entropy by allowing for random transformations (a broadcast channel). This leads to a unified perspective on several functional inequalities that have been gaining popularity in the context of proving impossibility results. We demonstrate that the information theoretic dual of the Brascamp-Lieb inequality is a convenient setting for proving properties such as data processing, tensorization, convexity and Gaussian optimality. Consequences of the latter include an extension of the Brascamp-Lieb inequality allowing for Gaussian random transformations, the determination of the multivariate Wyner common information for Gaussian sources, and a multivariate version of Nelson's hypercontractivity theorem. Finally we present an information theoretic characterization of a reverse Brascamp-Lieb inequality involving a random transformation (a multiple access channel).Comment: 5 pages; to be presented at ISIT 201

    The performance of socially responsible mutual funds: the role of fees and management companies

    Get PDF
    In this paper, we shed light on the debate about the financial performance of socially responsible investment (SRI) mutual funds by separately analyzing the contributions of before-fee performance and fees to SRI funds' performance and by investigating the role played by fund management companies in the determination of those variables. We apply the matching estimator methodology to obtain our results and find that in the period 1997-2005, US SRI funds had significantly higher fees and better before- and after-fee performance than conventional funds with similar characteristics. Differences, however, were driven exclusively by SRI funds run by management companies specialized in socially responsible investment.Socially responsible investment, Mutual fund fees, Mutual fund performance, Matching estimators

    Filtenna Integration Achieving Ideal Chebyshev Return Losses

    Get PDF
    This paper demonstrates that it is possible to find an ideal filter response (Chebyshew, Butterworth,..) considering the antenna as the last resonator of a filter under certain circumstances related with the antenna performance and the bandwidth of the filtenna device. If these circumstances are not accomplished, we can achieve excellent performance as well, by means of an iterative process the goal of which is defined by either a filter mask or a classical filter function itself. The methodology is based on the conventional coupling matrix technique for filter design and has been validated by fabricating a microstrip prototype using hairpin resonators and a rectangular patch antenna

    Nonlinear Performance of BAW Filters Including BST Capacitors

    Get PDF
    This paper evaluates the nonlinear effects occurring in a bulk acoustic wave (BAW) filter which includes barium strontium titanate (BST) capacitors to cancel the electrostatic capacitance of the BAW resonators. To do that we consider the nonlinear effects on the BAW resonators by use of a nonlinear Mason model. This model accounts for the distributed nonlinearities inherent in the materials forming the resonator. The whole filter is then implemented by properly connecting the resonators in a balanced configuration. Additional BST capacitors are included in the filter topology. The nonlinear behavior of the BST capacitors is also accounted in the overall nonlinear assessment. The whole circuit is then used to evaluate its nonlinear behavior. It is found that the nonlinear contribution arising from the ferroelectric nature of the BST capacitors makes it impractical to fulfill the linearity requirements of commercial filters

    Development and characterization of a new natural fiber reinforced thermoplastic (NFRP) with Cortaderia selloana (Pampa grass) short fibers

    Full text link
    [EN] In this work, fully bio-based thermoplastic composites are manufactured with bio-based polyethylene (from sugarcane) and short fibers coming from Cortaderia selloana (CS) wastes. These wastes are characterized by high cellulose content, which can provide high stiffness to the polymeric matrix. The effect of Cortaderia selloana short fibers on thermal properties has been evaluated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The effect of the filler load on mechanical properties has also been evaluated by tensile and impact tests as well as the effects of different coupling agents. Fiber-matrix interactions have been studied by scanning electron microscopy (SEM). The addition of 15-30 wt% Cortaderia selloana short fiber leads to high elastic and flexural modulus without remarkable changes in thermal degradation of the polymer composite. (C) 2017 Elsevier Ltd. All rights reserved.This work was funded by the Conselleria d'Educacio, Cultura i Esport (Generalitat Valenciana) Ref: GV/2014/008. The authors declare that they have no conflict of interest.Jorda-Vilaplana, A.; Carbonell-Verdu, A.; Samper, M.; Pop, A.; García Sanoguera, D. (2017). Development and characterization of a new natural fiber reinforced thermoplastic (NFRP) with Cortaderia selloana (Pampa grass) short fibers. Composites Science and Technology. 145:1-9. https://doi.org/10.1016/j.compscitech.2017.03.036S1914

    Poly(lactic acid) formulations with improved toughness by physical blending with thermoplastic starch

    Full text link
    This is the peer reviewed version of the following article: Ferri, J.M., Garcia-Garcia, D., Carbonell-Verdu, A., Fenollar, Octavio, Balart, Rafael. (2018). Poly(lactic acid) formulations with improved toughness by physical blending with thermoplastic starch.Journal of Applied Polymer Science, 135, 4, 45751-. DOI: 10.1002/app.45751, which has been published in final form at http://doi.org/10.1002/app.45751. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.[EN] This work focuses on poly(lactic acid) (PLA) formulations with improved toughness by physical blending with thermoplastic maize starch (TPS) plasticized with aliphatic¿aromatic copolyester up to 30 wt %. A noticeable increase in toughness is observed, due to the finely dispersed spherical TPS domains in the PLA matrix. It is worth to note the remarkable increase in the elongation at break that changes from 7% (neat PLA) up to 21.5% for PLA with 30 wt % TPS. The impact-absorbed energy is markedly improved from the relatively low values of neat PLA (1.6 J/m2) up to more than three times. Although TPS is less thermally stable than PLA due to its plasticizer content, in general, PLA/TPS blends offer good balanced thermal stability. The morphology reveals high immiscibility in PLA/TPS blends, with TPS-rich domains with an average size of 1 micrometre, finely dispersed which, in turn, is responsible for the improved toughness.Authors thank the Ministry of Economy and Competitiveness (MINECO), Ref.: MAT2014–59242-C2-1-R for their support. Authors also thank “Conselleria d’Educacio, Cultura i Esport”- Generalitat Valenciana, Ref.: GV/2014/008 for financial support.Ferri, J.; Garcia-Garcia, D.; Carbonell-Verdu, A.; Fenollar, O.; Balart, R. (2018). Poly(lactic acid) formulations with improved toughness by physical blending with thermoplastic starch. Journal of Applied Polymer Science. 135(4). https://doi.org/10.1002/app.45751S45751135

    Dynamical replica theoretic analysis of CDMA detection dynamics

    Full text link
    We investigate the detection dynamics of the Gibbs sampler for code-division multiple access (CDMA) multiuser detection. Our approach is based upon dynamical replica theory which allows an analytic approximation to the dynamics. We use this tool to investigate the basins of attraction when phase coexistence occurs and examine its efficacy via comparison with Monte Carlo simulations.Comment: 18 pages, 2 figure

    Plasticization effect of epoxidized cottonseed oil (ECSO) on poly(lactic acid)

    Full text link
    [EN] In this work, the use of an environmentally friendly plasticizer derived epoxidized cottonseed oil (ECSO) for poly(lactic acid) (PLA) is proposed. Melt extrusion was used to plasticize PLA formulations with different ECSO contents in the 0 - 10 wt.%. PLA formulation with 10 wt.% shows a remarkable increase in mechanical ductile properties with a percentage increase in elongation at break of more than 1100% and a noticeable increase in the impact absorbed energy. Differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA) revealed a clear decrease in the glass transition temperature of neat PLA as the ECSO content increased. Field emission scanning electron microscopy (FESEM) of fractured surfaces from impact tests showed an improvement of ductility with typical rough and porous topographies. Migration tests in n-hexane at different temperatures revealed very low migration properties thus leading to new interesting plasticizers for improved PLA industrial formulations.This research was supported by the Spanish Ministry of Economy and Competitiveness - MINECO, Ref: MAT2014-59242-C2-1-R. Authors also thank to "Conselleria d'Educacio, Cultura i Esport" - Generalitat Valenciana, Ref: GV/2014/008 for financial support. A. Carbonell-Verdu wants to thank Universitat Politecnica de Valencia for financial support through an FPI grant. D. Garcia-Garcia wants to thanks the Spanish Ministry of Education, Culture and Sports for their financial support through an FPU grant (FPU13/06011).Carbonell-Verdu, A.; Samper, M.; Garcia-Garcia, D.; Sanchez-Nacher, L.; Balart, R. (2017). Plasticization effect of epoxidized cottonseed oil (ECSO) on poly(lactic acid). Industrial Crops and Products. 104:278-286. https://doi.org/10.1016/j.indcrop.2017.04.050S27828610
    corecore