391 research outputs found

    From MANET to people-centric networking: Milestones and open research challenges

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    In this paper, we discuss the state of the art of (mobile) multi-hop ad hoc networking with the aim to present the current status of the research activities and identify the consolidated research areas, with limited research opportunities, and the hot and emerging research areas for which further research is required. We start by briefly discussing the MANET paradigm, and why the research on MANET protocols is now a cold research topic. Then we analyze the active research areas. Specifically, after discussing the wireless-network technologies, we analyze four successful ad hoc networking paradigms, mesh networks, opportunistic networks, vehicular networks, and sensor networks that emerged from the MANET world. We also present an emerging research direction in the multi-hop ad hoc networking field: people centric networking, triggered by the increasing penetration of the smartphones in everyday life, which is generating a people-centric revolution in computing and communications

    Joint Power Control and Structural Health Monitoring in Industry 4.0 Scenarios using Eclipse Arrowhead and Web of Things

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    The integration of legacy IoT ecosystems in Industry 4.0 scenarios requires human effort to adapt single devices. This process would highly benefit from features like device lookup, loose coupling and late binding. In this paper, we tackle the issue of integrating legacy monitoring systems and actuation systems in an industrial scenario, by looking into the Web of Things (WoT) as a communication standard and the Eclipse Arrowhead Framework (AHF) as a service orchestrator. More specifically, we propose a general architectural approach to enable closed-loop automation between the above mentioned legacy systems by leveraging the adaptation of the WoT to the AHF. Then, we develop a rule-based engine that enables the control of the actuation based on sensor values. Finally, we present a proof-of-concept use case where we integrate a Structural Health Monitoring (SHM) scenario with a power control actuation subsystem using the developed component

    A web application to optimization of transport in military operations

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    Transport is an operation necessary to carry out any logistical mission, especially in times of war, peace or natural disasters. The distribution of the necessary demanded resources is done from a military unit, to the different locations or military bases. However, operational efficiency depends on the planners. In more than 60% of trips, shipping and return isn’t efficient, even between the same units. The cause is the non-consolidation of trips and the lack of return load, coming from perimeter units. Planning is done without consolidating trips and in many cases on demand. It’s presented a web application, a parametric framework to any geographical area, given the integration with applications such as Google Maps®. Computational times are reasonable, given a to hardiness to the problem. The software architecture is scalable and extensible, complying with software quality practices present in ISO 25000

    Resource dedication problem in a multi-project environment

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    There can be different approaches to the management of resources within the context of multi-project scheduling problems. In general, approaches to multiproject scheduling problems consider the resources as a pool shared by all projects. On the other hand, when projects are distributed geographically or sharing resources between projects is not preferred, then this resource sharing policy may not be feasible. In such cases, the resources must be dedicated to individual projects throughout the project durations. This multi-project problem environment is defined here as the resource dedication problem (RDP). RDP is defined as the optimal dedication of resource capacities to different projects within the overall limits of the resources and with the objective of minimizing a predetermined objective function. The projects involved are multi-mode resource constrained project scheduling problems with finish to start zero time lag and non-preemptive activities and limited renewable and nonrenewable resources. Here, the characterization of RDP, its mathematical formulation and two different solution methodologies are presented. The first solution approach is a genetic algorithm employing a new improvement move called combinatorial auction for RDP, which is based on preferences of projects for resources. Two different methods for calculating the projects’ preferences based on linear and Lagrangian relaxation are proposed. The second solution approach is a Lagrangian relaxation based heuristic employing subgradient optimization. Numerical studies demonstrate that the proposed approaches are powerful methods for solving this problem

    Teaching tolerance

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    Babies born with Pompe disease require life-long treatment with enzyme-replacement therapy (ERT). Despite the human origin of the therapy, recombinant human lysosomal acid α glucosidase (GAA, rhGAA), ERT unfortunately leads to the development of high titers of anti-rhGAA antibody, decreased effectiveness of ERT, and a fatal outcome for a significant number of children who have Pompe disease. The severity of disease, anti-drug antibody (ADA) development, and the consequences thereof are directly related to the degree of the enzyme deficiency. Babies born with a complete deficiency GAA are said to have cross-reactive immunologic material (CRIM)–negative Pompe disease and are highly likely to develop GAA ADA. Less frequently, GAA ADA develop in CRIM-positive individuals. Currently, GAA-ADA sero-positive babies are treated with a combination of immunosuppressive drugs to induce immunological tolerance to ERT, but the long-term effect of these regimens is unknown. Alternative approaches that might redirect the immune response toward antigen-specific tolerance without immunosuppressive agents are needed. Methods leading to the induction of antigen-specific regulatory T cells (Tregs), using peptides such as Tregitopes (T regulatory cell epitopes) are under consideration for the future treatment of CRIM-negative Pompe disease. Tregitopes are natural T cell epitopes derived from immunoglobulin G (IgG) that cause the expansion and activation of regulatory T cells (Treg). Teaching the immune system to tolerate GAA by co-delivering GAA with Tregitope peptides might dramatically improve the lives of CRIM-negative babies and could be applied to other enzyme replacement therapies to which ADA have been induced

    GASP XXX. The spatially resolved SFR-Mass relation in stripping galaxies in the local universe

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    The study of the spatially resolved Star Formation Rate-Mass (Sigma_SFR-Sigma_M) relation gives important insights on how galaxies assemble at different spatial scales. Here we present the analysis of the Sigma_SFR-Sigma_M of 40 local cluster galaxies undergoing ram pressure stripping drawn from the GAs Stripping Phenomena in galaxies (GASP) sample. Considering their integrated properties, these galaxies show a SFR enhancement with respect to undisturbed galaxies of similar stellar mass; we now exploit spatially resolved data to investigate the origin and location of the excess. Even on ~1kpc scales, stripping galaxies present a systematic enhancement of Sigma_SFR (~0.35 dex at Sigma_M =108^M_sun/kpc^2) at any given Sigma_M compared to their undisturbed counterparts. The excess is independent on the degree of stripping and of the amount of star formation in the tails and it is visible at all galactocentric distances within the disks, suggesting that the star formation is most likely induced by compression waves from ram pressure. Such excess is larger for less massive galaxies and decreases with increasing mass. As stripping galaxies are characterised by ionised gas beyond the stellar disk, we also investigate the properties of 411 star forming clumps found in the galaxy tails. At any given stellar mass density, these clumps are systematically forming stars at a higher rate than in the disk, but differences are reconciled when we just consider the mass formed in the last few 10^8yr ago, suggesting that on these timescales the local mode of star formation is similar in the tails and in the disks.Comment: 20 pages, 13 figures, accepted for publication in Ap

    Dissecting the Mid-Infrared Heart of M83 with JWST

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    We present a first look at the MRS observations of the nucleus of the spiral galaxy M83, taken with MIRI onboard JWST. The observations show a rich set of emission features from the ionized and warm molecular gas, as well as traces of the dust properties in this highly star forming environment. To begin dissecting the complex processes taking place in this part of the galaxy, we divide the nucleus observations into four different regions. We find that the strength of the emission features appears to strongly vary in all four regions, with the south-east region displaying the weakest features tracing both the dust continuum and ISM properties. Comparison between the cold molecular gas traced by the 12^{12}CO (1-0) transition with ALMA and the H2_2 0-0 S(1) transition showed a similar spatial distribution throughout the nucleus. This is in contrast to the distribution of the much warmer H2_2 emission from the S(7) transition found to be concentrated mainly around the optical nucleus. We modeled the H2_2 excitation using the rotational emission lines and estimate a total molecular gas mass accounting for the warm H2_2 component of M(>>50 K)H2_{\rm H_{2}} = 59.33 (±4.75\pm 4.75) ×\times 106^{6} M_{\odot}. We compared this value to the total molecular gas mass inferred by probing the cold H2_2 gas through the 12^{12}CO (1-0) emission, M(CO)H2_{\rm H_{2}} = 14.99 ×\times 106^{6} M_{\odot}. Our findings indicate that \sim75\% of the total molecular gas mass in the core of M83 is contained in the warm H2_2 component. We also identify [OIV]25.89 μ\mum and [FeII]25.99 μ\mum emission (indicative of shocks) in all four nuclear regions with the strongest emission originating from the north-west section. We propose that the diffuse [FeII]25.99 μ\mum emission is an indication of the combined effects of both the collective supernova explosions and the starbursts themselves.Comment: 13 pages, 3 Tables, 8 Figures, to be submitted to Ap

    Shaken, not blown: the gentle baryonic feedback of nearby starburst dwarf galaxies

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    Baryonic feedback is expected to play a key role in regulating the star formation of low-mass galaxies by producing galaxy-scale winds associated with mass-loading factors β ⁣ ⁣1 ⁣ ⁣50\beta\!\sim\!1\!-\!50. We have tested this prediction using a sample of 19 nearby systems with stellar masses 107 ⁣< ⁣M/M ⁣< ⁣101010^7\!<\!M_\star/{\rm M}_{\odot}\!<\!10^{10}, mostly lying above the main sequence of star-forming galaxies. We used MUSE@VLT optical integral field spectroscopy to study the warm ionised gas kinematics of these galaxies via a detailed modelling of their Hα\alpha emission line. The ionised gas is characterised by irregular velocity fields, indicating the presence of non-circular motions of a few tens of km/s within galaxy discs, but with intrinsic velocity dispersion of 4040-6060 km/s that are only marginally larger than those measured in main-sequence galaxies. Galactic winds, defined as gas at velocities larger than the galaxy escape speed, encompass only a few percent of the observed fluxes. Mass outflow rates and loading factors are strongly dependent on MM_\star, star formation rate (SFR), SFR surface density and specific SFR. For MM_\star of 10810^8 M_\odot we find β0.02\beta\simeq0.02, which is more than two orders of magnitude smaller than the values predicted by theoretical models of galaxy evolution. In our galaxy sample, baryonic feedback stimulates a gentle gas cycle rather than causing a large-scale blow out.Comment: 20 pages, 11 figures, submitted to A&A. Comments are welcome

    MOKA3D: An innovative approach to 3D gas kinematic modelling. I. Application to AGN ionized outflows

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    Studying the feedback process of Active Galactic Nuclei (AGN) requires characterising multiple kinematical components, such as rotating gas and stellar disks, outflows, inflows, and jets. To compare the observed properties with theoretical predictions of galaxy evolution and feedback models and to assess the mutual interaction and energy injection rate into the interstellar medium (ISM), one usually relies on simplified kinematic models. These models have several limitations, as they often do not take into account projection effects, beam smearing and the surface brightness distribution of the emitting medium. Here, we present MOKA3D, an innovative approach to model the 3D gas kinematics from integral field spectroscopy observations. In this first paper, we discuss its application to the case of AGN ionised outflows, whose observed clumpy emission and apparently irregular kinematics are only marginally accounted for by existing kinematical models. Unlike previous works, our model does not assume the surface brightness distribution of the gas, but exploits a novel procedure to derive it from the observations by reconstructing the 3D distribution of emitting clouds and providing accurate estimates of the spatially resolved outflow physical properties (e.g. mass rate, kinetic energy). As an example, we demonstrate the capabilities of our method by applying it to three nearby Seyfert-II galaxies observed with MUSE at the VLT and selected from the MAGNUM survey, showing that the complex kinematic features observed can be described by a conical outflow with a constant radial velocity field and a clumpy distribution of clouds.Comment: 17 pages, 14 figure
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