1,059 research outputs found

    Living lab methodology as an assessment tool for mass customization

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    Mass customization has been regularly used as a growth strategy during the last decades. The strength of this approach stems from offering products adjusted to customers' individual needs, resulting in added value. The latter resides in the word 'custom,' implying unique and utilitarian products allowing for self-expression of the consumer. Researchers and practitioners however predominantly focused on the company's internal processes to optimize mass customization, often resulting in market failure. As a response, a framework with five factors determining the success of mass customization was developed. Additionally, Living Lab methodologies have been used to improve innovation contexts that were too closed. This paper will fill a gap in the literature by demonstrating that the integration of the five-factor framework in the Living Lab methodology is well suited to determine the possible success or failure of a mass-customized product in the market by means of a single case study

    Deuteron Spin Structure Functions at Small Bjorken-x

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    We investigate polarized deuteron structure functions at small values of the Bjorken variable, x < 0.1. In this region contributions from the coherent interaction of diffractively excited hadronic states with both nucleons become important. A proper treatment of this process requires an extension of the Glauber-Gribov multiple scattering theory to include spin degrees of freedom. In the kinematic domain of current fixed target experiments we observe that shadowing effects in g_1d are approximately twice as large as for the unpolarized structure function F_2d. Furthermore at x < 0.1 the tensor structure function b_1 is found to receive significant contributions from coherent double scattering.Comment: 30 pages, Revtex, include discussion on t-dependence of diffractive production processes, to appear in Phys. Rev.

    Minimisation du Content par une méthode d'active set pour les équations d'équilibrage hydraulique conduites par la pression

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    International audienceA new content-based, box-constrained, active-set projected Newton method is presented that solves for the heads, the pipe flows, and the nodal outflows of a water distribution system in which nodal outflows are pressure dependent. The new method is attractive because, by comparison with the previously published weighted least-squares energy and mass residuals (EMR) damped Newton method, (1) it typically takes fewer iterations, (2) it does not require damping, (3) it takes less wall-clock time, (4) it does not require the addition of any virtual elements, and (5) it is algorithmically easier to deal with. Various pressure-outflow relationships (PORs), which model nodal outflows, were considered and two new PORs are presented. The new method is shown, by application to eight previously published case study networks with up to about 20,000 pipes and 18,000 nodes, to be up to five times faster than the EMR method and to take between 34% and 70% fewer iterations than the EMR method

    Estimation de la demande pour les réseaux d'alimentation en eau potable : résolution d'un problème sous-déterminé par des algorithmes génétiques

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    International audienceModeling of water distribution systems is fundamental for the design, analysis and operation of any water network. As with all hydraulic models, water demands are one of the most important input components in the model. However, estimation of the demand parameters is usually complicated due to the stochastic behavior of the water consumptions. Several methods have been proposed for estimating water demands. Most of them have been developed based on given frameworks where the number of unknown parameters is assumed to be equal or less than the number of measurements. The outcomes, therefore, rely on this assumption, which can lead to significant approximation errors in real water distribution systems. The approach proposed in this paper does not require the number of known inputs to be equal to the number of variables. In fact, nodes in the model could each have a different demand pattern. The genetic algorithm approach adopted here shows that the average results of multiple GA runs can estimate the demand patterns at each node. Moreover, the model can also be used to estimate the flow rates and nodal heads at non-measured locations of the water network, although the accuracy of the estimation depends on number, type and location of the measurements. Results are shown and discussed for a literature case study tested for a 24-hour time period

    Des indicateurs clés de performances pour accroître la résilience des réseaux sur trois étapes

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    International audienceWater distribution networks (WDNs) are critical infrastructures that should face multiple and continuous changes and adverse operative conditions (due to abnormal events) that alter their normal service provision. The main objective of a WDN is to deliver the required amount of water to the customer under a certain threshold of the desired pressure and quality. Therefore, ensuring resilience and safety of WDSs are big concerns for water utilities. Several resilience key performance indicators have been suggested to quantify and assessing WDN resilience. Regarding the objectives of resilience, water utility managers require modelling tools to be able to predict how the WDN will perform during disruptive events and understand how the system can better absorb them. Tools such as: demand-driven modelling (DDM) for sufficient pressure conditions, and pressure-driven modelling (PDM) for insufficient pressure conditions, aid to simulate WDNs performance under adverse operative conditions. This work attempts to evaluate the network resilience. The proposed approach is based on an event-driven methodology and there is considered the time when the event occurs, when it evolves, and the sequence of the events. It should be carefully selected the type of the approach (PDM or DDM) used for the hydraulic model, as well as the system performance state and the uses of resilience power-based indicators. The results are promising in order to provide to water managers with a great depth of information and support better preparedness for WDNs

    Nuclear Quark and Gluon Distributions in Coordinate Space

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    In coordinate space, quark and gluon distributions of the nucleon are defined as correlation functions involving two field operators separated by a light-cone distance y+=2ly^+ = 2l. We study the nuclear modifications of these distributions. The largest effect is a strong depletion of parton distributions (shadowing) at large longitudinal distances, which starts for all parton species at l=2l=2 fm, i.e. at the average nucleon-nucleon separation in nuclei. On the other hand, the nuclear radius does not play a significant role. At $l intrinsic structure of individual nucleons is evidently not very much affected by nuclear binding. In particular, there is no evidence for a significant increase of the quark or gluon correlation length in bound nucleons

    Structure Functions are not Parton Probabilities

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    The common view that structure functions measured in deep inelastic lepton scattering are determined by the probability of finding quarks and gluons in the target is not correct in gauge theory. We show that gluon exchange between the fast, outgoing partons and target spectators, which is usually assumed to be an irrelevant gauge artifact, affects the leading twist structure functions in a profound way. This observation removes the apparent contradiction between the projectile (eikonal) and target (parton model) views of diffractive and small x_{Bjorken} phenomena. The diffractive scattering of the fast outgoing quarks on spectators in the target causes shadowing in the DIS cross section. Thus the depletion of the nuclear structure functions is not intrinsic to the wave function of the nucleus, but is a coherent effect arising from the destructive interference of diffractive channels induced by final state interactions. This is consistent with the Glauber-Gribov interpretation of shadowing as a rescattering effect.Comment: 35 pages, 8 figures. Discussion of physical consequences of final state interactions amplified. Material on light-cone gauge choices adde
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