254 research outputs found

    Sporadic cloud-based mobile augmentation on the top of a virtualization layer: a case study of collaborative downloads in VANETs

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    Current approaches to Cloud-based Mobile Augmentation (CMA) leverage (cloud-based) resources to meet the requirements of rich mobile applications, so that a terminal (the so-called application node or AppN) can borrow resources lent by a set of collaborator nodes (CNs). In the most sophisticated approaches proposed for vehicular scenarios, the collaborators are nearby vehicles that must remain together near the application node because the augmentation service is interrupted when they move apart. This leads to disruption in the execution of the applications and consequently impoverishes the mobile users’ experience. This paper describes a CMA approach that is able to restore the augmentation service transparently when AppNs and CNs separate. The functioning is illustrated by a NaaS model where the AppNs access web contents that are collaboratively downloaded by a set of CNs, exploiting both roadside units and opportunistic networking. The performance of the resulting approach has been evaluated via simulations, achieving promising results in terms of number of downloads, average download times, and network overheadMinisterio de Educación y Ciencia | Ref. TIN2017-87604-

    Cyclic lateral response of FRP-confined circular concrete-filled steel tubular columns

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    Concrete-filled steel tubular (CFT) columns are widely used as columns in many structural systems and a common failure mode of such tubular columns is inelastic outward local buckling near a column end. The use of fibre-reinforced polymer (FRP) jackets/wraps for the suppression of such local buckling has recently been proposed and has been proven to possess excellent potential in both retrofit/strengthening and new construction. This paper presents the results of an experimental study into the behaviour of large-scale FRP-confined CFT (CCFT) columns under combined axial compression and lateral loading. The test parameters included the stiffness of the FRP jacket and the loading scenario. The test results showed that the FRP jacket can effectively delay or even prevent outward local buckling at the end of a cantilevered CFT column, leading to significantly improved structural performance under combined constant axial compression and cyclic lateral loading. Compared to monotonic lateral loading, cyclic lateral loading was found to introduce more severe localized deformation near the column end and may lead to earlier FRP rupture within that region

    Exploiting multi-verse optimization and sine-cosine algorithms for energy management in smart cities

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    [EN] Due to the rapid increase in human population, the use of energy in daily life is increasing day by day. One solution is to increase the power generation in the same ratio as the human population increase. However, that is usually not possible practically. Thus, in order to use the existing resources of energy efficiently, smart grids play a significant role. They minimize electricity consumption and their resultant cost through demand side management (DSM). Universities and similar organizations consume a significant portion of the total generated energy; therefore, in this work, using DSM, we scheduled different appliances of a university campus to reduce the consumed energy cost and the probable peak to average power ratio. We have proposed two nature-inspired algorithms, namely, the multi-verse optimization (MVO) algorithm and the sine-cosine algorithm (SCA), to solve the energy optimization problem. The proposed schemes are implemented on a university campus load, which is divided into two portions, morning session and evening session. Both sessions contain different shiftable and non-shiftable appliances. After scheduling of shiftable appliances using both MVO and SCA techniques, the simulations showed very useful results in terms of energy cost and peak to average ratio reduction, maintaining the desired threshold level between electricity cost and user waiting timeUllah, B.; Hussain, I.; Uthansakul, P.; Riaz, M.; Khan, MN.; Lloret, J. (2020). Exploiting multi-verse optimization and sine-cosine algorithms for energy management in smart cities. Applied Sciences. 10(6):1-21. https://doi.org/10.3390/app1006209512110

    Networking vendor strategy and competition and their impact on enterprise network design and implementation

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    Thesis (M.B.A.)--Massachusetts Institute of Technology, Sloan School of Management; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science; in conjunction with the Leaders for Manufacturing Program at MIT, 2006.Includes bibliographical references (leaves 93-99).While a significant amount of literature exists that discuss platform strategies used by general IT vendors, less of it has to do with corporate networking technology vendors specifically. However, many of the same strategic principles that are used to analyze general IT vendors can also be used to analyze networking vendors. This paper extends the platform model that was developed by Michael Cusumano and Annabel Gawer to networking vendors, outlining the unique strategic aspects that the networking market possesses. The paper then reviews the strategy of the first dominant corporate datacom vendor, IBM, how it achieved its dominance, and how it lost it. The paper then discusses the strategies of various vendors who attempted to replace IBM as the dominant networking platform vendor and how they failed to do so. Finally, the paper discusses Cisco Systems, a vendor who did manage to achieve a level of dominance that parallels IBM's, and how that company has utilized its strategy to achieve and maintain its current dominance. Finally, Cisco's current strategic challenges are discussed. The impact of the strategies of the various vendors on the evolution of corporate networking is also discussed.by Ray Fung.S.M.M.B.A

    Semi-blind Channel Estimation Based on Superimposed Pilots for Single-Carrier MIMO Systems

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    On the geological significance of clastic parasequences

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    Parasequences recognized in clastic sedimentary successions of shallow-marine origin are considered by some geologists to be the fundamental building blocks of depositional sequences, even though problems in their definition and application have been identified by others, who instead advocate their abandonment as formal sequence stratigraphic units. To elucidate the geological significance of clastic parasequences and inform the debate on their use in stratigraphy, a quantitative characterization of the geometry, facies characteristics and timescale of deposition of 1163 parasequences has been undertaken based on a synthesis of data from outcrop and subsurface studies that are available in the scientific literature. Through a database compilation, the attributes of the studied parasequences are analysed with respect to the interpreted geological origin of the units, and with consideration of sources of bias and uncertainty. Particular emphasis is placed on assessing the following: (i) the importance of heuristics, and of data types and coverage in the recognition of parasequences; (ii) differences in parasequence characteristics observed across deltaic and shoreface depositional systems, and between the Quaternary and the ancient rock record; (iii) possible explanations for the range in timescales of deposition of parasequences; and (iv) the role of autogenic dynamics on the development of deltaic parasequences, partly based on a comparison with the recent evolution of modern deltas. The results demonstrate that parasequence definition and physical correlation suffer from subjectivity, and that significant variability exists in the spatio-temporal and architectural attributes of clastic parasequences. This gives rise to uncertainty that affects the use of parasequences as a framework for comparison of the architecture of packages of strata originating via shoreline regression: this uncertainty must be considered when using analogue data for subsurface predictions or when attempting comparative studies of clastic successions
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